Manual on Hydrocarbon Analysis (Astm Manual Series)

100 ~I:ARS

A PRO\T_NPARTNERSHIP

M alilla 011

6th Edition A, W, Drews, editor

Manual on Hydrocarbon

Analysis: 6th Edition A. W. Drews editor

ASTM Manual Series: MNL3 ASTM Stock #: MNL3

100 Barr Harbor Drive, West Conshohocken, PA 19428-2959

Library of Congress Cataloging-in-Publication Data Manual on hydrocarbon analysis--6th ed./A. W. Drews, editor (ASTM manual series: MNL 3) ASTM Stock #: MNL3 Includes bibliographical references and index ISBN 0-8031-2080-X 1. Petroleum productswAnalysis. 2. Hydrocarbons--Analysis. I. Drews, A.W. II. Series. TP691.M358 1998 665.5---dc21 98-25886 CIP

Copyright © 1998 by the AMERICAN SOCIETY FOR TESTING AND MATERIALS, West Conshohocken, PA. All rights reserved. This material may not be reproducedor copied, in whole or in part, in any printed, mechanical, electronic, film, or other distribution and storage media, without the written consent of the publisher.

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NOTE: This manual does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this manual to establish appropriate safety and health practices and determine the applicability of regulatory limitations pnor to use.

NOTE: The Society is not responsible, as a body, for the statements and opinions advanced in this publication.

Printed in Baltimore June 1998

Foreword THIS SIXTHEDITIONOF THE Manual on Hydrocarbon Analysis, sponsored by ASTM Committee D02 on Petroleum Products and Lubricants, has been expanded even further than the fifth edition. First appearing in 1963 as STP332, this manual was updated by Committee D02 in 1968, 1977, 1987, and 1992. In this 1998 edition, Part 2 has been expanded to include 26 additional ASTM test methods. Furthermore, the number of chapters has been increased from five to seven through the creation of a separate chapter, "Analysis of Kerosine, Diesel and Aviation Turbine Fuels," and a totally new chapter, "Analysis of Waxes." For additional information on the significance of tests, the reader is encouraged to consult the

Industry and governmental requirements for accurate, more detailed data in a shorter time frame have resulted in substantial method changes. Rapid instrumental techniques, incorporating automatic sampling and on-line instrumentation, are replacing many of the time-honored empirical and, even, wet-chemical procedures. Yet many of the established techniques are still utilized and, thus, they are included in this manual along with the methods that are replacing them. It is exciting to speculate what further changes will occur before issuance of the next edition. Publication of this manual would not have been possible without the efforts of the ASTM staff, the authors--N. G. Johansen, J. M. McCann, G. Hemighaus, T. M. Warne, A. J. Lubeck, A. D. Barker, C.H. Pfeiffer, the reviewers--S. E. Litka and N. D. Smith, and to L. A. Drews for collating, formatting, and reviewing the texts. I express my appreciation to all those who made this sixth edition a reality.

Manual on Significance of Tests for Petroleum Products, 6th Edition. Methodology is changing quickly, requiring revisions to existing methods and the standardization of new ones. The impact of computerization and microprocessors cannot be overemphasized. Modern data-handling capabilities allow highly detailed compositional analyses to be performed that were once only a vision. Some of these resulting methods have been standardized; others will follow rapidly as experience is gained.

A. W. Drews, editor Subcommittee D02.04 on Hydrocarbon Analysis

ool

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Purpose of Manual THE PURPOSEOF THIS MANUALis two-fold. The seven imroductory chapters provide the analyst with a comprehensive overview of current practices and tests relating to the analysis of hydrocarbons. The accompanying collection of ASTM test methods furnishes a convenient reference within a single volume. It is hoped that this combination will provide the reader with a clearer understanding and appreciation of this diversified subject.

iv

Contents INTRODUCTORY INFORMATION

Introduction Table 1--Summary of Product Types Produced from Petroleum Table 2--Summary of ASTM Test Methods (by subject) Table 3--Number of Isomeric Paraffins Table 4--Summary of Hydrocarbon Types in Petroleum Fractions

3 4 5 11 11

PART 1--DISCUSSIONOF ANALYSES BY PRODUCT TYPE Analysis of Cs and Lighter Hydrocarbons by N. G. J o h a n s e n Introduction Current Practices Future Trends 2 Analysis of Gasoline a n d Other Light Distillate Fuels by J. M. M c C a n n Introduction Current Practices Future Trends

Analysis o f Kerosine, Diesel, a n d Aviation T u r b i n e Fuel by G. H e m i g h a u s Introduction Current Practices Future Trends 4 Analysis of Viscous Oils by T. M. W a r n e Introduction Current Practices Future Trends

15 15 15 16 18 18 18 20

22 22 22 23 25 25 25 30

Analysis o f Waxes by A. D. B a r k e r Introduction Current Practices Future Trends

31 31 31 32 34 34 35 39

6 Analysis o f Crude Otis by A. J. L u b e c k Introduction Current Practices Future Trends Analysis o f A r o m a t i c Hydrocarbons by C. H. P f e i f f e r Introduction Current Practices Future Trends V

41 41 41 42

vi

CONTENTS PART 2 - - A S T M

TEST METHODS

The test methods in this section are arranged in alphanumeric sequence. The page numbers apply only to this manual and not to the standard documents as they appear in the annual ASTM Book of Standards. See Table 2 for a list of test methods by subject. The following is a list of all test methods included in Part 2. It includes all test methods referenced in the seven chapters except as indicated in the chapters. It does not include all of the test methods cited in Table 2. D5 D36 D56 D86 D87 D96 D97 D127 D130 D 189 D287 D323 D341 D445 D447 D473 D482 D524 D611 D664 D721 D848 D849 D850 D852 D853 D972 D976 D 1078 D1133 D 1142 D 1159 Dl160 D 1209 D1218 D1250 D1265 D1298 D1319 D1322 D1492 D1552 D1685 D1747 D1840

Test Method for Penetration of Bituminous Materials Test Method for Softening Point of Bitumen (Ring-and-Ball Apparatus) Test Method for Flash Point by Tag Closed Tester Test Method for Distillation of Petroleum Products at Atmospheric Pressure Test Method for Melting Point of Petroleum Wax (Cooling Curve) Test Method for Water and Sediment in Crude Oil by Centrifuge Method (Field Procedure) Test Method for Pour Point of Petroleum Oils Test Method for Drop Melting Point of Petroleum Wax Including Petrolatum Test Method for Detection of Copper Corrosion from Petroleum Products by the Copper Strip Tarnish Test Test Method for Conradson Carbon Residue of Petroleum Products Test Method for API Gravity of Crude Petroleum and Petroleum Products (Hydrometer Method) Test Method for Vapor Pressure of Petroleum Products (Reid Method) Viscosity-Temperature Charts for Liquid Petroleum Products Test Method for Kinematic Viscosity of Transparent and Opaque Liquids (and the Calculation of Dynamic Viscosity) Test Method for Distillation of Plant Spray Oils Test Method for Sediment in Crude Oils and Fuels Oils by the Extraction Method Test Method for Ash from Petroleum Products Test Method for Ramsbottom Carbon Residue of Petroleum Products Test Methods for Aniline Point and Mixed Aniline Point of Petroleum Products and Hydrocarbon Solvents Test Method for Acid Number of Petroleum Products by Potentiometric Titration Test Method for Oil Content of Petroleum Waxes Test Method for Acid Wash Color of Industrial Aromatic Hydrocarbons Test Method for Copper Strip Corrosion of Industrial Aromatic Hydrocarbons Test Method for Distillation of Industrial Aromatic Hydrocarbons and Related Materials Test Method for Solidification Point of Benzene Test Method for Hydrogen Sulfide and Sulfur Dioxide Content (Qualitative) of Industrial Aromatic Hydrocarbons Test Method for Evaporation Loss of Lubricating Greases and Oils Test Method for Calculated Cetane Index of Distillate Fuels Test Method for Distillation Range of Volatile Organic Liquids Test Method for Kauri-Butanol Value of Hydrocarbon Solvents Test Method for Water Vapor Content of Gaseous Fuels by Measurement of Dew-Point Temperature Test Method for Bromine Number of Petroleum Distillates and Commercial Aliphatic Olefins by Electrometric Titration Test Method for Distillation of Petroleum Products at Reduced Pressure Test Method for Color of Clear Liquids (Platinum-Cobalt Scale) Test Method for Refractive Index and Refractive Dispersion of Hydrocarbon Liquids Guide for Petroleum Measurement Tables Practice for Sampling Liquefied Petroleum (LP) Gases (Manual Method) Practice for Density, Relative Density (Specific Gravity) or API Gravity of Crude Petroleum and Liquid Petroleum Products by Hydrometer Method Test Method for Hydrocarbon Types in Liquid Petroleum Products by Fluorescent Indicator Adsorption Test Method for Smoke Point of Aviation Turbine Fuels Test Method for Bromine Index of Aromatic Hydrocarbons by Coulometric Titration Test Method for Sulfur in Petroleum Products (High-Temperature Method) Test Method for Traces of Thiophene in Benzene by Spectrophotometry Test Method for Refractive Index of Viscous Materials Test Method for Naphthalene Hydrocarbons in Aviation Turbine Fuels by Ultra Violet Spectrophotometry

47 50 54 64 77 80 87 95 97 103 109 112 120 126 134 137 141 144 152 159 166 172 175 177 182 184 186 190 193 200 202 213 222 240 243 247 249 252 257 263 269 272 277 280 284

CONTENTS D1945 D1946 D1988 D2007 D2158 D2163 D2171 D2306 D2360 D2386 D2425 D2426 D2500 D2501 D2502 D2503 D2504 D2505 D2549 D2593 D2597 D2622 D2650 D2710 D2712 D2784 D2786 D2878 D2887 D2892 D3054 D3120 D3205 D3227 D3230 D3235 D3239 D3241 D3246 D3279 D3524 D3606 D3700 D3701

Test Method for Analysis of Natural Gas by Gas Chromatography Practice for Analysis of Reformed Gas by Gas Chromatography Test Method for Mercaptans in Natural Gas Using Length-of-Stain Detector Tubes Test Method for Characteristic Groups in Rubber Extender and Processing Oils and Other Petroleum-Derived Oils by Clay-Gel Absorption Chromatographic Method Test Method for Residues in Liquefied Petroleum (LP) Gases Test Method for Analysis of Liquefied Petroleum (LP) Gases and Propene Concentrates by Gas Chromatography Test Method for Viscosity of Asphalts by Vacuum Capillary Viscometer Test Method for C8 Aromatic Hydrocarbon Analysis by Gas Chromatography Test Method for Trace Impurities in Monocyclic Aromatic Hydrocarbons by Gas Chromatography Test Method for Freezing Point of Aviation Fuels Test Method for Hydrocarbon Types in Middle Distillates by Mass Spectrometry Test Method for Butadiene Dimer and Styrene in Butadiene Concentrates by Gas Chromatography Test Method for Cloud Point of Petroleum Oils Test Method for Calculation of Viscosity-Gravity Constant (VGC) of Petroleum Oils Test Method for Estimation of Molecular Weight (Relative Molecular Mass) of Petroleum Oils from Viscosity Measurements Test Method for Relative Molecular Mass (Molecular Weight) of Hydrocarbons by Thermoelectric Measurement of Vapor Pressure Test Method for Noncondensable Gases in C2 and Lighter Hydrocarbon Products by Gas Chromatography Test Method for Ethylene, Other Hydrocarbons, and Carbon Dioxide in High-Purity Ethylene by Gas Chromatography Test Method for Separation of Representative Aromatics and Nonaromatics Fractions of High Boiling Oils by Elution Chromatography Test Method for Butadiene Purity and Hydrocarbon Impurities by Gas Chromatography Test Method for Analysis of Demethanized Hydrocarbon Liquid Mixtures Containing Nitrogen and Carbon Dioxide by Gas Chromatography Test Method for Sulfur in Petroleum Products by X-Ray Spectrometry Test Method for Chemical Composition of Gases by Mass Spectrometry Test Method for Bromine Index of Petroleum Hydrocarbons by Electrometric Titration Test Method for Hydrocarbon Traces in Propylene Concentrates by Gas Chromatography Test Method for Sulfur in Liquefied Petroleum Gases (Oxy-Hydrogen Burner or Lamp) Test Method for Hydrocarbon Types Analysis of Gas-Oil Saturates Fractions by High Ionizing Voltage Mass Spectrometry Test Method for Estimating Apparent Vapor Pressures and Molecular Weights of Lubricating Oils Test Method for Boiling Range Distribution of Petroleum Fractions by Gas Chromatography Test Method for Distillation of Crude Petroleum (15-Theoretical Plate Column) Test Method for Purity and Benzene Content of Cyclohexane by Gas Chromatography Test Method for Trace Quantities of Sulfur in Light Liquid Petroleum Hydrocarbons by Oxidative Microcoulometry Test Method for Viscosity of Asphalt with Cone and Plate Viscometer Test Method for Mercaptan Sulfur in Gasoline, Kerosine, Aviation Turbine, and Distillate Fuels (Potentiometric Method) Test Method for Salts in Crude Oil (Electrometric Method) Test Method for Solvent Extractables in Petroleum Waxes Test Method for Aromatic Types Analysis of Gas-Oil Aromatic Fractions by High Ionizing Voltage Mass Spectrometry Test Method for Thermal Oxidation Stability of Aviation Turbine Fuels (JFTOT Procedure) Test Method for Sulfur in Petroleum Gas by Oxidative Microcoulometry Test Method for Heptane Insolubles Test Method for Diesel Fuel Diluent in Used Diesel Engine Oils by Gas Chromatography Test Method for the Determination of Benzene and Toluene in Finished Motor and Aviation Gasoline by Gas Chromatography Practice for Containing Hydrocarbon Fluid Samples Using a Floating Piston Cylinder Test Method for Hydrogen Content of Aviation Turbine Fuels by Low Resolution Nuclear Magnetic Resonance Spectrometry

vii 287 302 307 311 318 322 327 334 337 342 346 352 355 358 361 365 368 373 379 385 392 402 406 413 420 426 432 439 444 455 484 488 494 498 503 508 514 527 538 545 548 552 559 563

viii

CONTENTS

D3710 D3760 D3797 D3798 D3961 D4006 D4007 D4045 D4052 D4053 D4057 D4177 D4291 D4294 D4307 D4367 D4377 D4419 D4423 D4424 D4492 D4530 D4534 D4628 D4629 D4735 D4737 D4808 D4810 D4815 D4864 D4888 D4927 D4928 D4929 D4951 D4953 D5002 D5060 D5134 D5135 D5185

D5186 D5190 D5191

Test Method for Boiling Range Distribution of Gasoline and Gasoline Fractions by Gas Chromatography Test Method for Analysis of Isopropyl Benzene (Cumene) by Gas Chromatography Test Method for Analysis of o-Xylene by Gas Chromatography Test Method for Analysis of p-Xylene by Gas Chromatography Test Method for Trace Quantities of Sulfur in Liquid Aromatic Hydrocarbons by Oxidative Microcoulometry Test Method for Water in Crude Oil by Distillation Test Method for Water and Sediment in Crude Oil by the Centrifuge Method (Laboratory Procedure) Test Method for Sulfur in Petroleum Products by Hydrogenolysis and Rateometric Colorimetry Test Method for Density and Relative Density of Liquids by Digital Density Meter Test Method for Benzene in Motor and Aviation Gasoline by Infrared Spectroscopy Practice for Manual Sampling of Petroleum and Petroleum Products Practice for Automatic Sampling of Petroleum and Petroleum Products Test Method for Trace Ethylene Glycol in Used Engine Oil Test Method for Sulfur in Petroleum Products by Energy-Dispersive X-Ray Fluorescence Spectroscopy Practice for Preparation of Liquid Blends for Use as Analytical Standards Test Method for Benzene in Hydrocarbon Solvents by Gas Chromatography Test Method for Water in Crude Oils by Potentiometric Karl Fischer Titration Test Method for Measurement of Transition Temperatures of Petroleum Waxes by Differential Scanning Calorimetry Test Method for Determination of Carbonyls in C4 Hydrocarbons Test Method for Butylene Analysis by Gas Chromatography Test Method for Analysis of Benzene by Gas Chromatography Test Method for Determination of Carbon Residue (Micro Method) Test Method for Benzene Content of Cyclic Products by Gas Chromatography Test Method for Analysis of Barium, Calcium, Magnesium and Zinc in Unused Lubricating Oils by Atomic Absorption Test Method for Trace Nitrogen in Liquid Petroleum Hydrocarbons by Syringe/Inlet Oxidative Combustion and Chemiluminescence Detection Test Method for Determination of Trace Thiophene in Refined Benzene by Gas Chromatography Test Method for Calculated Cetane Index by Four Variable Equation Test Method for Hydrogen Content of Light Distillates, Middle Distillates, Gas Oils, and Residua by Low Resolution Nuclear Magnetic Resonance Spectroscopy Test Method for Hydrogen Sulfide in Natural Gas Using Length-of-Stain Detector Tubes Test Method for Determination of MTBE, ETBE, TAME, DIPE, tertiary-Amyl Alcohol and Cl to C4 Alcohols in Gasoline by Gas Chromatography Test Method for Determination of Traces of Methanol in Propylene Concentrates by Gas Chromatography Test Method for Water Vapor in Natural Gas Using Length-of-Stain Detector Tubes Test Method for Elemental Analysis of Lubricant and Additive Components--Barium, Calcium, Phosphorus, Sulfur and Zinc by Wavelength-Dispersive X-Ray Fluorescence Spectroscopy Test Method for Water in Crude Oils by Coulometric Karl Fischer Titration Test Method for Determination of Organic Chloride Content in Crude Oil Test Method for Determination of Additive Elements in Lubricating Oils by Inductively Coupled Plasma Atomic Emission Spectrometry Test Method for Vapor Pressure of Gasoline and Gasoline-Oxygenate Blends (Dry Method) Test Method for Density and Relative Density of Crude Oils by Digital Density Analyzer Test Method for Determining Impurities in High-Purity Ethylbenzene by Gas Chromatography Test Method for Detailed Analysis of Petroleum Naphthas Through Nonane by Capillary Gas Chromatography Test Method for Analysis of Styrene by Capillary Gas Chromatography Test Method for Determination of Additive Elements, Wear Metals, and Contaminants in Used Lubricating Oils and Determination of Selected Elements in Base Oils by Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES) Test Method for the Determination of the Aromatic Content and Polynuclear Aromatic Content of Diesel Fuels and Aviation Turbine Fuels by Supercritical Fluid Chromatography Test Method for Vapor Pressure of Petroleum Products (Automatic Method) Test Method for Vapor Pressure of Petroleum Products (Mini Method)

567 578 582 586 590 596 606 617 621 625 628 646 670 673 676 679 684 688 691 694 696 700 705 708 712 716 720 723 728 731 739 744 747 753 760 766 771 778 783 786 797 800

806 811 816

CONTENTS D5194 D5234 D5236 D5273 D5274 D5287 D5291 D5292 D5303 D5307 D5384 D5386 D5442 D5443 D5453 D5454 D5482 D5503 D5504 D5580 D5599 D5622 D5623 D5708 D5713 D5762 D5769 D5776 D5799 D5808 D5842 D5845 D5853 D5863 D5917 D5986 D6069 D6144 D6159

Test Method for Trace Chloride in Liquid Aromatic Hydrocarbons Guide for Analysis of Ethylene Product Test Method for Distillation of Heavy Hydrocarbon Mixtures (Vacuum Potstill Method) Guide for Analysis of Propylene Concentrates Guide for Analysis of 1,3-Butadiene Product Practice for Automatic Sampling of Gaseous Fuels Test Method for Instrumental Determination of Carbon, Hydrogen, and Nitrogen in Petroleum Products and Lubricants Test Method for Aromatic Carbon Content of Hydrocarbon Oils by High Resolution Nuclear Magnetic Resonance Spectroscopy Test Method for Trace Carbonyl Sulfide in Propylene by Gas Chromatography Test Method for Determination of the Boiling Range Distribution of Crude Petroleum by Gas Chromatography Test Method for Chlorine in Used Petroleum Products (Field Test Kit Method) Test Method for Color of Liquids Using Tristimulus Colorimetry , Test Method for Analysis of Petroleum Waxes by Gas Chromatdgraphy Test Method for Paraffin, Naphthene and Aromatic Hydrocarbon Type Analysis in Petroleum Distillates Through 200°C by Multi-Dimensional Gas Chromatography Test Method for Determination of Total Sulfur in Light Hydrocarbons, Motor Fuels, and Oils by Ultraviolet Fluorescence Test Method for Water Vapor Content of Gaseous Fuels Using Electronic Moisture Analyzers Test Method for Vapor Pressure of Petroleum Products (Mini Method-Atmospheric) Practice for Natural Gas Sample-Handling and Conditioning Systems for Pipeline Instrumentation Test Method for Determination of Sulfur Compounds in Natural Gas and Gaseous Fuels by Gas Chromatography and Chemiluminescence Test Method for Determination of Benzene, Toluene, Ethylbenzene, p/m-Xylene, o-Xylene, C9 and Heavier Aromatics, and Total Aromatics in Finished Gasoline by Gas Chromatography Test Method for Determination of Oxygenates in Gasoline by Gas Chromatography and Oxygen Selective Flame Ionization Detection Test Method for the Determination of Total Oxygen in Gasoline and Methanol Fuels by Reductive Pyrolysis Test Method for Sulfur Compounds in Light Petroleum Liquids by Gas Chromatography and Sulfur Selective Detection Test Method for Determination of Nickel, Vanadium, and Iron in Crude Oils and Residual Fuels by Inductively Coupled Plasma (ICP) Atomic Emission Spectrometry Test Method for Analysis of High Purity Benzene for Cyclohexane Feedstock by Capillary Gas Chromatography Test Method for Nitrogen in Petroleum and Petroleum Products by Boat-Inlet Chemiluminescence Test Method for Determination of Benzene, Toluene and Total Aromatics in Finished Gasoline by Gas Chromatography/Mass Spectrometry Test Method for Bromine Index of Aromatic Hydrocarbons by Electrometric Titration Test Method for Determination of Peroxides in Butadiene Test Method for Determining Organic Chloride in Aromatic Hydrocarbons and Related Chemicals by Microcoulometry Practice for Sampling and Handling of Fuels for Volatility Measurement Test Method for the Determination of MTBE, ETBE, TAME, DIPE, Methanol, Ethanol and tertButanol in Gasoline by Infrared Spectroscopy Test Method for Pour Point of Ct:ude Oils Test Method for Determination of Nickel, Vanadium, Iron, and Sodium in Crude Oils and Residual Fuels by Flame Atomic Absorption Spectrometry Test Method for Trace Impurities in Monocyclic Aromatic Hydrocarbons by Gas Chromatography and External Calibration Test Method for the Determination of Oxygenates, Benzene, Toluene, Cs-C12 Aromatics and Total Aromatics in Finished Gasolines by Gas Chromatography/Fourier Transform Infrared Spectroscopy (GC/FTIR) Test Method for Trace Nitrogen in Aromatic Hydrocarbons by Oxidative Combustion and Reduced Pressure Chemiluminescence Detection Test Method for Analysis of AMS (ct-Methylstyrene) by Gas Chromatography Test Method for Determination of Hydrocarbon Impurities in Ethylene by Gas Chromatography

ix 821 824 826 842 845 847 852 857 864 870 877 88O 883 890 900 906 908 912 917 922 931 939 943 948 953 956 961 972 975 977 981 988 993 1000 1005 1011

1025 1030 1034

x

CONTENTS

D6160 D6212

Test Method for Determination of Polychlorinated Biphenyls (PCBs) in Waste Materials by Gas Chromatography Test Method for Total Sulfur in Aromatic Compounds by Hydrogenolysis and Rateometric Colorirnetry

1039 1054

Introductory Information

Introduction

THE PETROLEUMANALYSTis a problem solver and, as such, is constantly required to make method choices. In the past, two questions were most frequently associated with the method selection process. • What properties can be determined to solve a particular production problem? • What methods are appropriate to determine a specific property? Now the analyst is faced with additional complications. These include the need to produce results faster, in more detail, at lower concentration levels; to reduce costs (usually in the form of analyst labor); and to provide higher-quality results. In addition, federal and state regulations, particularly on spark-ignition engine fuels, influence method choice. Thus, method choice is now even more difficult. Fortunately, technology has advanced dramatically. Instrumental techniques have prospered and continue to improve rapidly. Gas chromatography, long a mainstay, is using faster, more efficient columns along with element-specific detectors. Furthermore, hyphenated techniques such as gas chromatography-mass spectrometry (GC/MS) and liquid chromatography-mass spectrometry (LC/MS) are providing separations that were once only a vision. Other spectrometric techniques--near infrared (NIR), Fourier transform infrared (FTIR), and nuclear magnetic resonance (NMR), to name a few, are being utilized on-line virtually unattended to provide real-time data. Nevertheless, the method of choice will still depend on the boiling range (or carbon number) of the sample to be analyzed, and, following this, the resources available to the analyst. Therefore, in this manual, the hydrocarbons, along with their associated methods, are discussed according to boiling range. The first five chapters of this manual are arranged beginning with "Analysis of C5 and Lighter Hydrocarbons," followed by "Analysis of Gasoline and Other Light Distillate Fuels," "Analysis of Kerosine, Diesel, and Aviation Turbine Fuel," "Analysis of Viscous Oils," and "Analysis of Waxes." Chapter 6, "Analysis of Crude Oils," deals with the total span of compounds, from gases to non-distillables. Chapter 7, "Analysis of Aromatics Hydrocarbons," is a special case that discusses a particular class of compounds that has increasingly gained importance in octane enhancing and, particularly, in petrochemicals.

Table 1 shows the carbon number range and boiling points (of normal paraffins) for some of the more common petroleum products of commerce. ASTM methods that may be applied to these boiling ranges are shown in Table 2. These tables are provided as an overview of the complex hydrocarbon analysis field; they do not show all of the methods that might be applicable. Details on many of these analytical methods, as well as techniques and procedures under development, are discussed in the appropriate chapters. Crude petroleum and fractions (or products) obtained from it contain a complex variety of compounds. It is interesting to note that as the number of carbon atoms increases, the possible complexity of petroleum mixtures also rapidly increases (see Table 3). Consequently, detailed analysis of the higher boiling fractions becomes increasingly difficult. Instrumental techniques have improved this situation, and the data being obtained provide extremely valuable input for the design, control, and evaluation of petroleum processes. Traditionally, however, these techniques were not available, It was necessary (and in many cases, satisfactory) to empirically determine specific physical properties that could be related to product quality and process control. Although the number of these tests is diminishing, many of them are still in common use. Some appear in this text because product specifications reference them and some referee methods still utilize the more basic testing procedures. Additionally, "classes" or types of hydrocarbons were and still are determined based on the capability to isolate them by separation techniques. The four types usually sought are paraffins, olefins, naphthenes, and aromatics. Paraffinic hydrocarbons include both normal and branched alkanes. Olefins refer to normal and branched alkenes that contain one or more double or triple carbon-carbon bonds. Naphthene (not to be confused with "naphthalene") is a term of the petroleum industry that refers to the saturated cyclic hydrocarbons or "cycloalkanes." Finally, aromatics include all hydrocarbons containing one or more rings of the benzenoid structure. These general hydrocarbon classifications are complicated by many combinations of the above types, for example, olefinic aromatics (styrene) or alkylbenzenes (cumene). Table 4 presents a summary of the hydrocarbon types usually found in specific petroleum fractions.

4

MANUAL ON HYDROCARBON ANALYSIS

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V

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INTRODUCTORY INFORMATION Table 2--Summary of ASTM Test Methods Number of CarbonAtoms Boiling Rangeof Normal Paraffmsat 760 mm Hg, °C

C1-C2 -161 to -89

C:Cs -42to +36

Physical Methods D5, Penetration of bituminous materials D36, Ring and ball softening point D56, Flash by tag closed cup tester D86, Distillation of petroleum products D87, Melting point of wax

Co.-CIo 6 9 t o 174

X X

X X

X

X X

X X X

X

X X X X X

X

X

X

X X X

X X X

X

X X

X X

X

X

X

X

X

X

D852, Solidification point of benzene D972, Evaporation losses of greases & oils DlOIS, Purity from freezing point DI016, Purity from freezing point D 1078, Distillation of volatile organic liquids

D1837, Volatility of LP gases D2158; Residue in LP gases D2171, Viscosity of asphalts D2386, Freezing point of aviation fuels D2500, Cloud point of peltoleum oils

>(2)) >355

X

13482, Ash from petroleum products D524, Ramsbottom carbon residue D611, Aniline point D721, Oil content of petroleura waxes D850, Distillation of industrial aromatics

D 1322, Smoke point of aviation turbine fuels D 1493, Solidification point of organic chemicals D 1657, Relative density of light hydrocarbons D 1747, Refractive index of viscous materials D 1807, Refractive index of insulating oils

X

X X

D287, API gravity by hydrometer D323, Vapor pressure (Reid method) D445, Kinematic viscosity D447, Distillation of plant spray oils D473, Sediment by extraction

Water vapor of gaseous fuels Distillation at reduced pressure Refractive index & dispersion Vapor pressure of LP gases Relative density of liquids

C~s-Czo 287 to 343

X X

D92, Flash and fire Cleveland open cup D93, Flash and fire by Pensky-Martens closed cup D97, Pour point D 127, Melting point of wax D189, Couradson carbon residue

D1142, D 1160, D 1218, D1267, D 1298,

CH-CI~ 196 to 270

X

x

X X X

X

X

X

X

X

X

X

X

X

X X

X

X

X X X X

I

X X

X X X X

X X

X

5

6

MANUAL ON HYDROCARBON ANALYSIS T a b l e 2 - continued Number of Carbon Atoms Boiling Range of Normal Paraffins at 760 nun Hg, °C

CI-C2 -161 to -89

C3-C~ -42to +36

D2503, Molecular weight D2533, Vapor-liquid ratio of gasoline D2892, Distillation of crude oil D3205, Viscosity of asphalt (cone & plate) D3279, n-Heptane insolubles

C6-C1o 6 9 t o 174

X X

X X X X

D4809, Precise heat of combustion D4953, Vapor pressure of gasoline oxygenate blends D5002, Density of erude oil D5 ! 90, Vapor pressure (automatic method) D5 ! 91, Vapor pressure (mini method)

X X

>C~ >355

X

X

X

X X X

X X X X X

X X X

X

X

X

X

X X

X X

D5236, Distillation of heavy oils D5482, Vapor pressure of petroleum products D5853, Pour point of crude oils

X X

Correlative Methods D341, Viscosity-temperature charts for hydrocarbons D976, Calculation of octane index of distillate fuels D 1250, Petroleum measurement tables D2270, Calculation of viscosity index D250 !, Viscosity-gravityconstant of oils

X

X

X X

X X

X X

X

X X X

X X X X X

X

X

X

X X

X

X

X X

Liquid Chromatographic Methods D 1319, Hydrocarbon types by FIA D2007, Rubber extender & processing oils D2549, Aromatics & nonaromatics in distillates D5186, Aromatics in diesel fuel by SFC X X X

X X

X

D3343, Hydrogen content of aviation gasoline D4529, Estimation of heat of combustion of aviation fuels D4737, Calculated oetane index

Gas Chromatographic Methods D1945, Analysis of natural gas D1946, Analysis of reformed gas D2163, LP gases & propylene concentrates D2268, High-purity heptane & isooctane D2306, Xylene isomers in xylene

X

Ct,-C2o 287 to 343

X

D3828, Flash point by Seta flash closed tester D4052, Density by digital density meter D4206, Sustained burning test by Seta flash D4207, Sustained burning test by wick method D4530, Micro carbon residue

D2502, Molecular weight of oils D2598, Physical properties of LP gases D2889, Calculation of true vapor pressure D3238, Carbon distribution & structure analysis, n-d-M D3338, Estimation of heat of combustion of aviation fuels

Cu-C~5 196 to 270

X X X

X X X

X

X

X

X X X X X

X X X X

X X

INTRODUCTORY INFORMATION Table 2 - continued Number of Cazbon Atoms

BoilingRange of NormalPaxaffmsat 760 mm Hg, °C

CcC~

C~'Cs

-161to -89

-42to +36

Cs-Clo

69to 174

C.-Cis 196 to 270

C,6-C~ 287 to 343

>C= >355

X

X

X

X X

X

....,

D2360, D2426, D2427, D2504, D2505, ,,

Trace impurities in aromatics Butadiene dimer & styrene C2-C5 in gasoline Nonenndensibles in C3 & lighter Analysis of high-purity ethylene

X X X X

X X X

X

,

D2593, D2597, D2712, D2820, D2887,

Butadiene purity and hydrocarbon impurities Natural gas-liquid mixtures Hydrocarbon Iraces in propylene C,-C~ hydrocarbons in atomosphere Boiling range distribution of petroleum fractions

D3054, D3524, D3525, D3606, D3710,

Cyolohexane purity & benzene content Diesel fuel in used iubc oils Gasoline diluent m engine oils Benzene & toluene in gasoline Boiling range distribution of gasoline

D3760. D3797, D3798. D3962, D4367,

Analysis of isopropylbenzene Purity of o-xylene Purity of p-xylene Analysis of styrene Benzene content of solvents

D4420, D4424, D4492, D4534, D4626,

Aromatics in finished gasolines Butane-butene mixtures Purity of benzene Benzene content of cyclic hydrocarbons Calculation of response factors

D4735. IM815, D4864, D5060, D5134, D5135,

Trace thiophene in benzene Alcohols and MTBE in gasoline Methanol in propylene Impurities in ethylbenzene Analysis of naphthas Analysis of styrene

D5303, D5307, D5442, D5443, D5504,

Trace COS in propylene Boiling range distribution of crude oil Petroleum wax Hydrocarbon types Sulfur compounds by GC & chemiluminescence

D5580, Aromatics in gasoline D5599,'Oxygenates in gasoline by GC & OFID D5623, Sulfur compounds by GC & sulfur selective detector D5713, Benzene purity D5769, Aromatics in gasoline by GC-MS

X X X

X X X X X

X

X X

X X

X X X

X

X X X X X X X

X

X

X X X

X

X

X

X

X X

X X

X X X X X X X

X X

X

X

X X X X X X X

X

7

8

MANUAL ON HYDROCARBON A N A LYSI S T a b l e 2 - continued Number o f Carbon Atoms Boiling Range o f Normal Paraffins at 760 m m Hg, °C

D5917, Trace impurities in aromatics D5986, Oxygenates and aromatics in gasoline by GC/FTIR I)6144, Analysis of cx-methylstyrene 136159, Impurities in ethylene D6160, PCBs in waste material Spectroscopic Methods D 1840, Naphthalenes in aviation turbine fuels D2425, Hydrocarbon types in distillates by MS D2650, Chemical composition of gases by MS D2786, Analysis of gas-oil saturate fractions by MS D2789, Hydrocarbon types in gasoline by MS

C~-C2 -161 to -89

C:Cs -42 to +36

D 1492, Bromine index of aromatics D2710, Bromine index by electrometric titration D4423, Carbonyl in C4 hydrocarbons D5776, Bromine index D5799, Peroxides in butadiene

Cu-Cls 196to 270

C,6-C20 287to 343

>Cm >355

X

X

X

X X

X X

X X X X

X

X X

D3239, Aromatic types in gas oil aromatic fractions by MS D3701, Hydrogen content of fuels by NMR D4053, Benzene content of gasoline by IR D4808, Hydrogen content of petroleum products by NMR D5292, Aromatic carbon and hydrogen by NMR D5845, Oxygenates in gasoline by IR Chemical Methods D483, Unsulfonated residue of spray oils I)664, Neutralization number by potentiometric titration D847, Acidity in solvent naphthas and aromatics D974, Neutralization number by color-indicator method D 1159, Bromine number by electrome~c titration

C6-Cio 69to 174

X X

X

X

X X

X

X X X

X X

X

X

X

X X X

X X X X

X X

X X

X X

X X

X X

X X

X X

X X X X

X

X X

Miscellaneous Methods

D 130, Copper strip corrosion D156, Saybolt color D ! 87. Burning quality of kerosine D381, Existent gum in fuels D525, Oxidation stability of gasoline (induction period)

X X X X X

D613, Cetane quality of diesel fuels D848, Acid wash color of aromatics D849, Copper corrosion of aromatics D873, Oxidation stability of aviation fuels D909, Knock characteristics of aviation fuels

X X

D 1133, Kauri-Butanol value D1265, Sampling LP gas D2121, Polymer in styrene D2274, Oxidation stability of distillate fuels D2276, Particulate contamination in aviation turbine fuels

X

X X X

X

X X X X

X X

INTRODUCTORY INFORMATION

T a b l e 2 - continued Number of Carbon Atoms Boiling Range of Normal P~affms at 760 mm Hg, °C

CcC~ -161 to -89

D2624, Electrical conductivity of aviation and distillate fuels D2699, Knock characteristics by research octane D2700, Knock characteristics by motor octane D2713, Dryness of propane (valve freeze) D2780, Solubility of fixed gases in liquids

D2878, D2885, D3235, D3241, D3700,

Estimating vapor pressure of lubricating oils Knock characteristics by on-line analyzers Solvent extractables in waxes Thermal oxid. stab. of aviation turbine fuel (JFTOT) Sampling using floating piston cylinder

D5274, Guide for analysis of butadiene D5287, Automatic sampling of gaseous fuels D5386, Color of liquids D5503, Natural gas sample-handling D5842, Sampling of fuels for volatility

D2622, Sulfur by X-ray D2709, Water and sediment in fuels D2784, Sulfur in LP gases D3120, Trace sulfur by oxidative microcoulometry D3227, Mercaptans in distillates (potentiometric)

Cn-Cts 196 to 270

C~6-C~o 287 to 343

X

X

>(22o >355

X X

X X

X

X X

X

X X X

X

X

X X

X X X

X X X X X

X X X X

X X

X X X

X

X X

X X X

X X X X

X X X X

X X

X

X

X X

X X

X X X

X X X

X X

Non-Hydrocarbon Methods D95, Water by distillation D96, Water and sediment in crude oils D129, Sulfur by bomb method D808, Chlorine in petroleum products D853, H2S and SO2in aromatics D!266, Sulfur by lamp method D1552, Sulfur by high-temperature method D1685, Thiophene in benzene D1988, Mercaptans in natural gas D2420, Hydrogen sulfide in LP gases

Ce,-CIo 69to 174

X X

D3948, Water separation charact, of aviation turbine fuel D4057, Manual sampling of petroleum D4 i 77, Automatic sampling of petroleum D4291, Ethylene glycol in used engine oil D4307, Preparation of liquid blends D4419, Transition temperatures of wax by DSC D4740, Stability of residual oils by spot test D5184, AI and Si in fuel oils by ICP-AES and AAS D5234, Guide for analysis of ethylene D5273, Guide for analysis of propylene

C3-Cs -42 to +36

X

X

X X

X X

X

X X

X X

X

X

X X

X X

X

9

10

MANUAL ON HYDROCARBON A N A L Y S I S Table 2 - continued

Number of Carbon Atoms Boiling Range of Normal Paraffins at 760 mm Hg, °C D3230. D3231, D3237, D3246, D3341,

Salt in crude oil Phosphorus in gasoline Lead in gasoline by AAS Sulfur in gases by oxidative microcoulometry Lead in gasoline (iodine monochloride)

CfC~ -161 to -S9

X

X

134951, D5185, D5194, D5291, D5384,

Additive elements in lube oils by ICP-AES Additive elements in lube oils by ICP-AES Trace chloride in aromatics C, H and N in petroleum products Chlorine in used oils

D5453, D5454, D5622, D5708, D5762,

Sulfur in fuels and oils Water vapor in gaseous fuels Total oxygen by reductive pyrolysis Ni, V and Fe in crude oil by ICP-AES Nflrogen by chemiluminescence

D5808, D5863, D6069, D6212,

Organic chloride in aromatics by microenulometry Ni, V, Fe and Na in crude oil by AAS Trace nitrogen in aromatics by chemiluminescence Total sulfur in aromatics by rateometric colorimetry

X X X

Cn'C~5 196 to 270

C~6-C2o 287 to 343

>C~ >355

X

X

X

X

X X

IM047, Phosphorus in lubricating oils D4294, Total sulfur by XRF D4377, Water in crude oil by Karl Fischer D4628, Ba, Ca, Mg, and Zn in oils by AAS D4629, Trace nitrogen by chemiluminescence D4888, Water in natural gas D4927, Ba, Ca, P, S and Zn by XRF D4928, Water in crude oils IM929, Chloride in crude oils

c.-c,o 69to 174

X

D3605, Trace metals in fuels by AAS D3961, Sulfur in aromatics by oxidative microcoulometry D4006, Water in crude oil by distillation D4007, Water and sediment in crude oil by centrifuge D4045, Sulfur by hydrogenolysis and rateometric colorimetry

1)4810, H2Sin natural gas

C.-Cs -42 to +36

X

X X

X

X

X X X X

X X X

X X X

X X

X X

X X

X

X

X X X X X

X X X X X

X X

X X

X X X

X X X

X X

X X

X X

X

X X

X

X

X X X

X X

X X

X

X

X

X

X X X X

X

X

X X

X

X X X X

INTRODUCTORY

INFORMATION

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12

MANUAL ON HYDROCARBON A N A L Y S I S

A manual on hydrocarbon analysis would not be complete without considerable attention to non-hydrocarbons that occur in all crude oils and products. These impurities can range in concentration from parts-per-billion to percent levels, depending on the type of crude oil or specific fraction. Accurate determination of elements such as sulfur, nitrogen, or oxygen as well as numerous metals can be of the utmost importance. The analyst is constantly being challenged to determine these materials at lower and lower levels. Even minute concentrations of these elements can be fatal to sensitive catalytic systems that are now being used in most refining processes. With the introduction of oxygenated motor fuels, the determination of oxygen-containing compounds has become mandatory while complicating the determination of hydrocarbons in their presence. Finally, a word on correlative methods. Numerous calculation methods have been developed to relate chemical or physical properties to composition or processability. Other correlative methods allow direct comparison of data that have been obtained by totally different procedures. A particularly good example of this is the correlation of boiling range by gas

chromatography (ASTM Test Methods D2887 on Boiling Range Distribution of Petroleum Fractions by Gas Chromatography and D3710 on Boiling Range Distribution of Gasoline and Gasoline Fractions by Gas Chromatography) as compared to physical distillation (ASTM Test Methods D86 on Distillation of Petroleum Products at Atmospheric Pressure and D 1160 on Distillation of Petroleum Products at Reduced Pressures). ASTM Subcommittee D02.04 on Hydrocarbon Analysis is actively engaged in finalizing this particular correlation. Other correlation methods are available, some of which are listed in Table 2. As analytical technology and the petroleum industry change, older methods will be revised or discontinued and new ones developed. Within this dynamic system, new challenges will continue to face the analyst as quickly as older problems are solved. Through the efforts of ASTM members, new concepts will be evaluated, proven, and formalized as consensus test methods. A. W. Drews Subcommittee D02.04 on Hydrocarbon Analysis

Part l--Discussion of Analyses

by Product Type

Analysis of Cs and Lighter Hydrocarbons

1

by Neil G. Johansen

INTRODUCTION

ble among these are ASTM Standard Practices D5287, Automatic Sampling of Gaseous Fuels,1 D5503, Natural Gas Sample-Handling and Conditioning Systems for Pipeline Instrumentation, I D1265, Sampling Liquefied Petroleum (LP) Gases (Manual Method), l and D3700, Containing Hydrocarbon Fluid Samples Using a Floating Piston Cylinder? Sampling of low-pressure materials is described in ASTM Standard Practices D4057, Manual Sampling of Petroleum and Petroleum Products/ D4177, Automatic Sampling of Petroleum and Petroleum Products, ~ and D5842, Sampling and Handling of Fuels for Volatility Measurement. 1 The preparation of gaseous and liquid blends is described in ASTM Standard Practices D4051, Preparation of LowPressure Gas Blends, 2 and D4307, Preparation of Liquid Blends for Use as Analytical Standards. 1 While sampling of C1 and C2 hydrocarbons is typically performed using stainless steel cylinders, either lined or unlined, other containers are employed dependent upon particular situations; for example, glass cylinder containers or PVF sampling bags. The preferred method for sampling C a and C4 hydrocarbons is by the use of piston cylinders, ASTM Standard Practice D3700, although sampling these materials as gases is also acceptable in many cases. The sampling of C5 and higher hydrocarbons is dependent upon the vapor pressure of the sample. Piston cylinders or pressurized steel cylinders are advisable for high-vapor pressure samples (containing significant amounts of light gases), while atmospheric sampling may be used for low-vapor pressure samples.

THE LIGHTHYDROCARBONS--methane (C~), ethane (C2), propane (Ca), and the butanes (C4), either in the gas phase or liquefied, are primarily used for heating, motor fuels, and as feedstocks for chemical processing. The pentanes/pentenes (C5) are products of natural gas or petroleum fractionation or refinery operations (i.e., reforming and cracking) that are removed for use as chemical feedstocks. The olefins--ethene (ethylene), propene (propylene), butenes (butene-1, isobutylene, cis- and trans-butene-2, and the butadienes), pentenes, and pentadienes are materials produced by various refining processes involving the use of the saturated hydrocarbons as feedstocks. Mixtures of these hydrocarbons are commonly encountered in material testing, and the composition varies depending upon the source and intended use of the material. Other non-hydrocarbon constituents of these mixtures are important analytes since they may be useful products or may be undesirable as a source of processing problems. Some of these components are helium, hydrogen, argon, oxygen, nitrogen, carbon monoxide, carbon dioxide, sulfur, and nitrogen containing compounds, as well as heavier hydrocarbons. Desired testing of these hydrocarbon mixtures usually involves the determination of bulk physical or chemical properties and component speciation and quantitation. ASTM addresses the characterization and specification of the C~ to C5 hydrocarbon materials and products through several venues. Committee D03 is responsible for gaseous fuels; Committee D02, Subcommittee H is responsible for liquefied petroleum gas; Committee D02, Subcommittee D is responsible for hydrocarbons for chemical and special uses, while Committee D02, Subcommittee 4 has responsibility for test methods involving hydrocarbons in general. Committees D19 (Water) and D22 (Sampling and Analysis of Atmospheres) address environmental concerns involving light hydrocarbons.

Analysis ASTM test methods for gaseous fuels and petroleum products have been developed over many years, extending back into the 1930s. Bulk physical property tests, such as density and heating value, as well as some compositional tests, such as the Orsat analysis and the mercuric nitrate method for the determination of unsaturation, were widely used. Mass spectrometry became the method of choice for compositional analysis of light hydrocarbons, and ASTM Test Method D2650, Chemical Composition of Gases by Mass Spectrometry/ was standardized in 1967 to replace several older methods. Currently the mass spectrometry method has been replaced, in practice, by gas chromatography as the technique of choice for fixed gas and hydrocarbon speciation.

CURRENT PRACTICES

Sampling One of the more critical aspects for the analysis of light hydrocarbons is the question of sampling. Sampling of gaseous and liquefied materials is addressed in a variety of specific sampling methods, and many of the test methods themselves contain additional sampling requirements. Nota-

1Appears in this publication. 2Annual Book of ASTM Standards, Vol. 05.02.

15

16

MANUAL ON HYDROCARBON ANALYSIS

Natural and Reformed Gas

Light Olefins (C2, C3, C. and C5)

ASTM Test Method D1945, Analysis of Natural Gas by Gas Chromatography, ~and ASTM Practice D 1946, Analysis of Reformed Gas by Gas Chromatography, 1 describe procedures for the determination of hydrogen, helium, oxygen, nitrogen, carbon monoxide, carbon dioxide, methane, ethene, ethane, propane, butanes, pentanes, and hexanes-plus in natural and reformed gases by packed column gas chromatography. These compositional analyses are used to calculate many other properties of gases, such as density, heating value, and compressibility. The first five components listed are determined using a molecular sieve 13X column (argon carrier gas), while the remaining components are determined using polydimethylsiloxane partition or porous polymer columns. The hexanes-plus analysis is accomplished by backflushing the column after the elution of pentane or by the use of a bacldlushed precolumn. Important constituents of natural gas not accounted for in these analyses are moisture (water) and hydrogen sulfide, as well as other sulfur compounds. Water content is determined by ASTM Test Methods D 1142, Water Vapor Content of Gaseous Fuels by Measurement of Dew-Point Temperature, ~ D5454, Water Vapor Content of Gaseous Fuels Using Electronic Moisture Analyzers, ~ or D4888, Water Vapor in Natural Gas Using Length-of-Stain Detector Tubes) ASTM Test Method D5504, Sulfur Compounds in Natural Gas and Gaseous Fuels by Gas Chromatography and Chemiluminescence, I best accomplishes sulfur compound determination, although ASTM Test Methods D 1988, Mercaptans in Natural Gas Using Length-of-Stain Detector Tubes, ~ and D4810, Hydrogen Sulfide in Natural Gas Using Length-ofStain Detector Tubes, ~ can also be used with some loss in accuracy.

Characteristics and corresponding test methods for these materials have been outlined in three ASTM standard guides: D5234, Analysis of Ethylene Product, ~ D5273, Analysis of Propylene Concentrates, 1 and D5274, Analysis of 1,3Butadiene Product. 1 A proposed Guide for the Analysis of Isoprene is being developed. These guides list properties to be measured and the range of values expected, as well as appropriate test methods where available. Hydrocarbon analysis of ethene is accomplished using ASTM Test Methods D2505, Ethylene, Other Hydrocarbons, and Carbon Dioxide in High-Purity Ethylene by Gas Chromatography, l and ASTM Test Method D6159, Hydrocarbon Impurities in Ethylene by Gas Chromatography.l D6159 is a new test method using wide-bore (0.53-mm) capillary columns, including a A1203/KCI PLOT column. Currently, ASTM Test Method D2504 is recommended for determination of noncondensable gases, and ASTM Test Method D2505 is used for the determination of carbon dioxide; however, a new method is under development in ASTM to address these analyses. ASTM Test Methods D2712, Hydrocarbon Traces in Propylene Concentrates by Gas Chromatography, 1 and D2163, also a gas chromatographic method, are currently recommended for the determination of hydrocarbon impurities in propene. ASTM Test Method D4864, Determination of Traces of Methanol in Propylene Concentrates by Gas Chromatography, l is used for methanol determination. ASTM Test Method D5303, Trace Carbonyl Sulfide in Propylene by Gas Chromatography, 1 is used for carbonyl sulfide determination with a flame photometric detector. ASTM Test Method D3246, Sulfur in Petroleum Gas by Oxidative Microcoulometry, 1 is currently recommended for the determination of total sulfur, and the method is being revised to be more generally applicable to light hydrocarbon analysis. Commercial butylenes, high-purity butylenes, and butanebutylene mixtures are analyzed for hydrocarbon constituents by ASTM Test Method D4424, Butylene Analysis by Gas Chromatography) Hydrocarbon impurities in 1,3-butadiene are determined by ASTM Test Method D2593, Butadiene Purity and Hydrocarbon Impurities by Gas Chromatography) Butadiene dimer and styrene are determined in butadiene using ASTM Test Method D2426, Butadiene Dimer and Styrene in Butadiene Concentrates by Gas Chromatography) Carbonyls in C4 hydrocarbons are determined by a titrimetric technique using ASTM Test Method D4423, Determination of Carbonyls in C4 Hydrocarbons. ~ ASTM Test Method D5799, Determination of Peroxides in Butadiene, t is used for peroxide determination.

Liquefied Petroleum (LP) Gases Propane, iso-butane, and butane generally constitute this sample type and are used for heating, motor fuels, and as chemical feedstocks. ASTM Test Methods D2597, Analysis of Demethanized Hydrocarbon Liquid Mixtures Containing Nitrogen and Carbon Dioxide by Gas Chromatography,l D2163, Analysis of Liquefied Petroleum (LP) Gases and Propene Concentrates by Gas Chromatography, l and D2504, Noncondensable Gases in C2 and Lighter Hydrocarbon Products by Gas Chromatography, ~ are methods for determining light hydrocarbons and some fixed gases in LP gases. Total sulfur is determined by ASTM Test Method D2784, Sulfur in Liquefied Petroleum Gases (Oxy-Hydrogen Burner or Lamp). ) Sulfur compound determination is made using ASTM Test Method D5623, Sulfur Compounds in Light Petroleum Liquids by Gas Chromatography and Sulfur Selective Detection. ~Trace total organic and bound nitrogen is determined using ASTM Test Method D4629, Trace Nitrogen in Liquid Petroleum Hydrocarbons by Syringe/Inlet Oxidative Combustion and Chemiluminescence Detection.~ The current test method for heavy residues in LP gases is ASTM Test Method D2158, Residues in Liquefied Petroleum (LP) Gases, t which involves evaporation of an LP Gas sample, measuring the volume of residue and observing the residue for oil stain on a piece of filter paper.

FUTURE TRENDS In general, gas chromatography will undoubtedly continue to be the method of choice for characterization of light hydrocarbon materials. New developments in higher-speed techniques for gas chromatographic instrumentation and data processing will lead to new and revised test methods. New and improved detection devices and techniques, such as chemiluminescence, atomic emission, and mass spectroscopy, will enhance selectivity, detection limits, and analytical productivity. Laboratory automation through autosampling,

CHAPTER 1--ANALYSIS OF Cs AND LIGHTER HYDROCARBONS computer control, and data handling will provide improved precision and productivity, as well as simplified method operation. Development of test methods for process (on-line) analysis and validation of these analyses are continuing under the direction of ASTM Committee D02.0D, Section l and D02.25. A proposed gas chromatographic/selective detection method is under development for the trace analysis of sulfur compounds in ethene and propene. ASTM Test Method D2163 is quite old. It utilizes lower resolution packed columns, a less sensitive detector, and manual peak area measurement. Thus, it is technically out of date, and Committee D02.0D is currently in the process of developing a revision for the determination of hydrocarbons in LP gases and lower-purity mixtures of C3 and C4 hydrocarbons. The revision will still be performance based, but the recommended column will be the A1203/KC1 PLOT column, as used in the recently standardized ASTM Test Method D6159,

17

as well as in another test method under development for high-purity propene. A continuing problem for LP gas characterization is the accurate determination of heavy residues (i.e., oils) in LP gas. New test methods have been proposed using procedures similar to those employed in gas chromatographic simulated distillation, and this development work is continuing. The development of test methods for C5 hydrocarbons (olefins) has begun recently and should result in ASTM standards in the near future. Various petroleum refinery process streams, often containing olefinic compounds, are generically referred to as "refinery gas." Although no ASTM test method is available for this determination, several instrumentation and technology suppliers market automated gas chromatographic systems as "refinery gas analyzers." ASTM standardization of this technology would be beneficial to users of these analyzers.

Analysis of Gasoline and Other Light Distillate Fuels by James M. McCann

INTRODUCTION

During the early 1950s, instrumental analytical techniques, such as mass spectrometry, infrared, and ultraviolet spectroscopy, were being explored and used for hydrocarbon composition and structural analysis. Beginning with the mid 1950s, publications on gas chromatography began to appear in the literature, and this new technique was soon being used for analyzing a wide variety of hydrocarbon streams. As commercial instrumentation was developed, the application of gas chromatography grew rapidly, with volumes of information being published from its beginning up to the present time. Recently, more rapid spectrometry methods such as infrared and near-infrared and the use of hyphenated analytical techniques, for example GC-MS, have been applied.

THE CHALLENGETO DEVELOPmore accurate and precise test methods for the analysis of gasoline or automotive sparkignition engine fuel has been tremendously influenced by federal and state regulations covering the production of reformulated gasolines (RFG) with tight limits on many parameters [1]. 1 Examples of these new fuels include U.S. Environmental Protection Agency (EPA) RFG and California Air Resources Board (CARB) Phase 2 Gasoline. The regulated RFG test parameters include vapor pressure, distillation, benzene content, total aromatics, total olefins, individual oxygenates, oxygen content, and total sulfur. Regulatory requirements have enhanced the need for better test methods to control manufacturing and the distribution of gasolines. The addition of alcohol and ether as important blending components to gasoline to meet air quality standards has necessitated modifying some existing test methods and the development of new procedures. The desire to reduce manufacturing costs, coupled with the regulatory requirements, have enhanced the application of more cost effective test methods including rapid screening procedures and wider use of online analyzers. In this chapter, a brief history of ASTM method development for hydrocarbon analysis of gasoline is given. The focus, however, will be on some of the test parameters required for today's reformulated gasolines including many of the new test methodologies. ASTM standardization of methods for hydrocarbon analysis started in 1942 when Committee D02, Technical Division on Gasoline, established a subgroup to standardize a procedure for the determination of aromatics in gasolines for use by the military. This method was first issued in March of 1943 as Emergency Standard ES 45, Test for Olefins, Aromatics, Paraffins, and Naphthenes in Aviation Gasoline (Without Distillation Into Fractions). 2 This method was a combination of several procedures, some of which are still commonly used. In 1948, a procedure was described by A. L. Conrad and later refined by D. W. Cridle and R. L. LeTourneau for determining olefins, aromatics, and saturates in cracked gasoline. This procedure evolved into ASTM Test Method D1319, Hydrocarbon Types in Liquid Petroleum Products by Fluorescent Indicator Adsorption, 3 often abbreviated as "FIA."

CURRENT PRACTICES Analysis of Gasoline Range Hydrocarbons The following is a review of applicable test methods that can be used to measure some of the key parameters in gasoline range hydrocarbons.

Distillation The primary method specified for determining boiling range of gasoline continues to be ASTM Test Method D86, Distillation of Petroleum Products at Atmospheric Pressure. 3 The use of automated instrumentation has been incorporated into the method. ASTM Test Method D3710, Boiling Range Distribution of Gasoline and Gasoline Fractions by Gas Chromatography, 3 (GC), can be used for determining the boiling point properties of oxygenate-free gasoline distillates. ASTM D3710 has the advantage that it uses a smaller sample size and can be more easily automated, but D3710 data are not directly equivalent to that obtained by D86 distillation. ASTM D3710 data are being used by some companies and vendors by applying correlations to predict D86 distillation data for various refinery streams. Improvements in the GC simulated distillation procedures have been implemented in some laboratories and are being evaluated in ASTM D02.04, Section H. Improvements include rapid gas chromatography techniques using very narrow bore capillary gas chromatography columns that will potentially reduce analysis time to a few minutes [2].

~The italic numbers in brackets refer to the references at the end of this chapter. 21944 Annual Book of ASTM Standards, Part III. 3Appears in this publication.

Vapor Pressure The vapor pressure of gasoline is a critical physical test parameter for today's gasoline. ASTM Test Method D323,

18

CHAPTER 2--ANALYSIS OF GASOLINE AND OTHER DISTILLATE FUELS Vapor Pressure of Petroleum Products (Reid Method), 3 had been widely used in the past. ASTM Test Method D5191, Vapor Pressure of Petroleum Products (Mini Method), 3 is now most commonly referenced in gasoline regulations. This method requires less sample and is much easier and faster to run. Other ASTM Test Methods for vapor pressure of gasoline include D4953, Vapor Pressure of Gasoline and Gasoline-Oxygenate Blends (Dry Method), a D5190, Vapor Pressure of Petroleum Products (Automatic Method), 3 and D5482, Vapor Pressure of Petroleum Products (Mini MethodAtmospheric). 3

Oxygenates ASTM test methods have been developed to measure ethers and alcohols in gasoline range hydrocarbons, because oxygenated components such as methyl-tert-butylether and ethanol are common blending components in current gasolines. ASTM Test Methods D4815, MTBE, ETBE, TAME, DIPE, tertiary-Amyl Alcohol and C1 to C4 Alcohols in Gasoline by Gas Chromatography, a and D5599, Oxygenates in Gasoline by Gas Chromatography and Oxygen Selective Flame Ionization Detection, 3 were adopted for measuring oxygenates and oxygen content. ASTM D4815 is a widely used method and is currently the designated test method in California. ASTM D5599 is a GC capillary column method employing an oxygen selective flame ionization detector and was based upon the EPA designated test for oxygenates in gasoline [3 ]. It can detect any oxygenated component that elutes from the gas chromatographic (GC) column. ASTM D5986, Oxygenates, Benzene, Toluene, C8-C12 Aromatics and Total Aromatics in Finished Gasoline by Gas Chromatography/Fourier Transform Infrared Spectroscopy (GC/FTIR), 3 is more complex, but it can determine oxygenates, benzene, and total aromatics in a single analysis. ASTM Test Method D5622, Total Oxygen in Gasoline and Methanol Fuels by Reductive Pyrolysis, 3 can be used to directly determine mass percent total oxygen in fuels. ASTM Test Method D5845, MTBE, ETBE, TAME, DIPE, Methanol, Ethanol and tert-Butanol in Gasoline by Infrared Spectroscopy,3 is particularly useful as a rapid portable screening tool for oxygenates in gasoline. In addition, gas chromatography with an atomic emission detector has been used by laboratories to measure specific oxygenated components in gasoline [4,5 ].

Benzene and Aromatics The accurate measurements of benzene and total aromatics in gasoline are regulated test parameters in modern gasoline. ASTM Test Method D3606, Benzene and Toluene in Finished Motor and Aviation Gasoline by Gas Chromatography, 3 (GC), is a procedure accepted by the EPA as the designated test for benzene in gasoline. The precision and accuracy of D3606 is diminished in gasolines containing ethanol or methanol, since these components do not completely separate from the benzene peak. A modified version of D3606 is practiced using a different internal standard and a different set of gas chromatographic columns that gives better separation of ethanol or methanol containing fuels. This modified version of the test has not been cooperatively tested by ASTM. ASTM Test Method D5580, Benzene, Toluene, Ethylbenzene, p/m-Xylene, o-Xylene, C9 and Heavier Aromatics and Total Aromatics in Finished Gasoline by Gas Chromatography, 3

19

was developed to include fuels containing commonly encountered alcohols and ethers. D5580 has been accepted as the designated test for determining benzene and total aromatics in California Phase 2 gasolines. Hyphenated analytical instrumental methods including ASTM Test Method D5769, Benzene, Toluene and Total Aromatics in Finished Gasolines by Gas Chromatography/Mass Spectrometry3 (GC/MS), and ASTM D5986, (GC/FTIR), also accurately measure benzene in gasoline. ASTM D5769 is based upon the EPA GC/MS procedure for aromatics [6 ]. The results of ASTM D02 Subcommittee 4 round robin studies have shown that there is no significant bias among methods D5769, D5580, and D5986 for benzene in gasoline. Benzene can also be measured by ASTM Test Method D4053, Benzene in Motor and Aviation Gasoline by Infrared Spectroscopy? Other improved infrared procedures are being considered for standardization in ASTM. ASTM D 1319 (FIA) has traditionally been used to measure aromatics as well as olefins and saturates in gasoline. ASTM Test Method D5443, Paraffin, Naphthene, and Aromatic Hydrocarbon Type Analysis in Petroleum Distillates through 200°C by Multi-Dimensional Gas Chromatography, 3 can be used to measure hydrocarbon types by carbon number. Olefins, if present, are converted to saturates and are included in the paraffin and naphthene distribution. The scope of ASTM D5443 excludes hydrocarbons containing oxygenates. An extended version of the technique, which has not been standardized, measures paraffins, isoparaffins, olefins, naphthenes, and aromatics (PIONA) in gasoline range hydrocarbons [6 ]. ASTM Test Methods D5580 (GC), D5769 (GC/ MS), and D5986 (GC/FTIR) were adopted as a new test methods for aromatics in gasoline including fuels containing oxygenates. ASTM D5769 is based upon an EPA procedure for aromatics in gasoline [7 ]. The results of these total aromatics tests are not necessarily equivalent.

Total Olefins ASTM Test Method D 1319 (FIA) is widely used for measuring total olefins in gasoline fractions as well as aromatics and saturates. D 1319 results must be corrected for the presence of oxygenates, and the precision of the method is poor. A titration procedure, ASTM Test Method D 1159, Bromine Number of Petroleum Distillates and Commercial Aliphatic Olefins by Electrometric Titration, 3 provides an approximation of olefin content within a sample, while ASTM Test Method D2710, Bromine Index of Petroleum Hydrocarbons by Electrometric Titration, 3 can be valuable for determining trace olefin levels. These methods do not directly measure total olefins, and the results are affected by the type of olefinic compound present. Cooperative studies are underway in ASTM D02.04 to find a better test method for total olefins. Cooperative work has been done to validate new gas chromatographic methods that trap the olefins on silver nitrate impregnated traps. These include a gas chromatographic multi-dimensional procedure for oxygenates and paraffin, olefin, naphthene, aromatic (O-PONA) hydrocarbon types in petroleum distillates and a GC fast total olefins analyzer (FTO) method. The FTO method has the advantage that the analysis time is quicker. The O-PONA method is an expanded version of ASTM D5443 and

20

MANUAL ON HYDROCARBON ANALYSIS

gives a detailed breakdown of the oxygenates and hydrocarbon types by carbon number. The use of supercritical fluid chromatography, (SFC), applied to gasoline analysis with a flame ionization detector, was first reported in 1984 by T. A. Norris [8 ]. Studies in Section C of ASTM D02.04 found the chromatographic column difficult to reproduce. Recent work has begun on a new multi-dimensional column approach for determining total olefins in gasoline by SFC. SFC combined with gas chromatography and or mass spectrometry has been reported giving a more detailed hydrocarbon type characterization [9,10 ]. Mass spectrometry techniques have also recently been reported for the determination of olefins in hydrocarbons or gasoline. These include the use of hydrogenation techniques and acetone chemical ionization mass spectrometry [11,12 ].

Detailed Hydrocarbon Analysis ASTM Test Method D5134, Detailed Analysis of Petroleum Naphthas through n-Nonane by Capillary Gas Chromatography, a is applicable to olefin-free liquid hydrocarbon mixtures including virgin naphthas, reformates, and alkylates. Higher resolution gas chromatography capillary column techniques are in routine use in petroleum laboratories today to provide a detailed analysis of most of the individual hydrocarbons in gasoline, including many of the oxygenated blending components. Software is also available that allows one to summarize the data according to hydrocarbon type and predict other parameters such as vapor pressure and distillation from the results. High-resolution GC procedures for the detailed analysis of gasoline are being considered for adoption as standard ASTM test methods. Capillary GC techniques can be combined with mass spectrometry [13 ] to enhance the identification of the individual components and hydrocarbon types.

Sulfur Content Sulfur-containing components exist in gasoline range hydrocarbons. Individual sulfur components can be speciated using ASTM Test Method D5623, Sulfur Compounds in Light Petroleum Liquids by Gas Chromatography and Sulfur Selective Detection) This method uses a gas chromatographic capillary column coupled with either a sulfur chemiluminescence detector or atomic emission detector (AED). The total sulfur content is an important test parameter in gasoline. The most widely specified method for total sulfur content is ASTM Test Method D2622, Sulfur in Petroleum Products by X-Ray Spectrometry. 3 ASTM Test Methods D5453, Total Sulfur in Light Hydrocarbons, Motor Fuels and Oils by Ultraviolet Fluorescence, 3 and D4045, Sulfur in Petroleum Products by Hydrogenolysis and Rateometric Colorimetry, 3 are also applicable, particularly at lower sulfur levels. Studies have also been conducted in ASTM D02.03 on Elemental Analysis to improve these tests and evaluate newer methods.

Octane N u m b e r ASTM Test Methods D2700, Motor Octane Number of Spark-Ignition Engine Fuel, 4 D2699, Research Octane Number of Spark-Ignition Engine Fuel, 4 and D2885, Research and Motor Method Octane Ratings Using On-Line Analyzers, 4 are

4Annual Book of ASTM Standards, Vol. 05.04.

standardized tests used to determine the ignition quality of gasoline. Aviation gasolines are tested by ASTM Test Method D909, Knock Characteristics of Aviation Gasolines by the Supercharge Method. 4 Calculation of octane numbers based on compositional analysis obtained by gas chromatography has also been practiced by some companies. Octane can be predicted by using principle component regression of chromatographic data [14 ]. Today, spectroscopy techniques such as near-infrared (NIR), infrared (IR) spectroscopy, and nuclear magnetic resonance (NMR) are applied by many companies and instrument vendors for the prediction of octane numbers and other parameters of gasoline [15-18 ].

Analysis of Hydrocarbon Solvents Although "hydrocarbon solvents" are not considered "fuels," it is appropriate to mention them because they are hydrocarbon distillates. Solvent tests are generally performed to ensure the quality of a given product as supplied by the producer to the consumer. Many solvent tests are of a somewhat empirical nature such as aniline point, ASTM Test Method D611, Aniline Point and Mixed Aniline Point of Petroleum Products and Hydrocarbon Solvents, 3 and kauributanol number, ASTM Test Method D1133, Kauri-Butanol Value of Hydrocarbon Solvents. 3 These are cited in specifications and serve a useful function as control tests. Solvent purity, however, is monitored mainly by gas chromatography, with individual non-standardized tests routinely being used by the associated industry. One method that resulted from health concerns and the need to reduce the benzene contents of solvents is ASTM Test Method D4367, Benzene in Hydrocarbon Solvents by Gas Chromatography. 3

FUTURE TRENDS It is anticipated that regulations and specifications for gasoline will continue to evolve. To meet these future regulations and the changing requirements of the automotive industry, the composition of gasoline will also be changed and improved. New analytical methods will be developed to accurately test these new fuels. Petroleum-testing laboratories will apply more rapid spectroscopy techniques, faster chromatography methods, and hyphenated analytical techniques capable of measuring multiple parameters in a single analysis. More precise test methods will be implemented employing smaller sample sizes, less toxic reagents, and fewer calibration materials. The acceptance of alternative test methodologies will expand as government agencies recognize performance-based test methods for fuel analysis. In particular, the utilization and acceptance of more cost effective on-line test methods, including techniques such as NIR, FTIR, NMR, and Fiber-Optic FT Raman Spectrometry, will continue to expand [19,20 ].

REFERENCES [1 ] McCann, J. M., "ASTM Faces New Testing Challenges Created by Reformulated Gasoline Regulations," ASTM Standardization News, June 1994, pp. 23-25.

C H A P T E R 2 - - A N A L Y S I S OF G A S O L I N E A N D O T H E R D I S T I L L A T E F U E L S [2 ] Giarrocco, V., "Two-Minute Simulated Distillation Analysis of Gasoline Range Materials Using Short 100-/zm Diameter Caprilary Columns," Hewlett-Packard Company Application Note 228-370, Publication Number 23-5965-6416E, January 1997, Hewlett-Packard Company, Wilmington, DE. [3 ] EPA GC/OFID Method, EPA, Dec. 15, 1993, Final Rulemaking on Reformulated Gasoline. [4 ] Quimby, Giarrocco, V. and Sullivan, J., "Fast Analysis of Oxygen and Sulfur Compounds in Gasoline by GC-AED,"Journal of High Resolution Chromatography, Vol. 15, November 1992, pp. 705-709. [5 ] Diehl, J., Finkbeiner, J., and DiSanzo, F., "Determination of Ethers and Alcohols in Reformulated Gasolines by GC/AED," Journal of High Resolution Chromatography, Vol. 18, No. 2, February 1995, pp. 108-110. [6 ] DiSanzo, F. P. and Giarrocco, V. J., "Analysis of Pressurized Gasoline-Range Liquid Hydrocarbon Samples by Capillary Column and PIONA Analyzer Gas Chromatography," Journal of Chromatographic Science, Vol. 26, 1988, pp. 258-401. [7 ] EPA GC/MS Method, EPA, Dec. 15, 1993, Final Rulemaking on Reformulated Gasoline. [8 ] Norris, T. A. and Rawdon, M. G., "Determination of Hydrocarbon Types in Petroleum Liquids by Supercritical Fluid Chromatography with Flame Ionization Detection," Analytical Chemistry, Vol. 56, 1984, pp. 1767-1769. [9] Chen, E.N. Jr., Drinkwater, D.E., and McCann, J.M., "Compositional Analysis of Hydrocarbon Groups in GasolineRange Materials by Multidimensional SFC-Capillary GC," Journal of Chromatographic Science, Vol. 33, 1995, pp. 353-359. [10 ] Drinkwater, D. E., Chen, E.N. Jr., and Nero, V. P., "Direct Analysis of Fuels by Supercritical Fluid Chromatography/Mass Spectrometry," Proceedings, 44th ASMS Conference on Mass Spectrometry and Allied Topics, 1997, Portland, Oregon. [11 ] Roussis, S. G. and Fedora, J. S., "Determination of Alkenes in Hydrocarbon Matrices by Acetone Chemical Ionization Mass

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Spectrometry," Analytical Chemist~, Vol. 97, 1997, pp. 15501556.

[12 ] Cheng, M., Hudson, J., Drinkwater, D., and Nero, V., "Total Olefin in Gasoline Determined by Mass Spectrometry and Hydrogenation," Proceedings, 44th ASMS Conference on Mass Spectrometry and Allied Topics, 1997, Portland, Oregon. [13 ] Teng, S. T. and Williams, A. D., "Detailed Hydrocarbon Analysis of Gasoline by GC-MS (SI-PIONA)," Journal of High Resolution Chromatography, Vol. 19, 1994, pp. 469-475. [14 ] Crawford, N. F. and Hellmuth, W. W., "Refinery Octane Blend Modeling Using Principle Components Regression of Gas Chromatographic Data," Fuel, Vol. 69, 1990, pp. 443-447. [15 ] Welch, W. T., Bain, M. L., Russell, K., Maggard, S. M., and May, J. M., "Experience Leads to Accurate Design of NIR Gasoline Analysis Systems," Oil & Gas Journal, June 27, 1994, pp. 48-56. [16 ] Myers, M. E., Stollsteimer, J., and Wims, A. M., "Determination of Gasoline Octane Numbers from Chemical Composition," Analytical Chemistry, Vol. 47, No. 13, November 1975, pp. 23012304. [17 ] Ichikawa, M., Nonaka, N., Amono, H., Takada, I., Ishimori, H., Andoh, H., and Kumamoto, K., "Proton NMR Analysis of Octane Number for Motor Gasoline: Part IV," Applied Spectroscopy, Vol. 46, No. 8, 1992, p. 1294. [18 ] Andrade, J. M., Muniategui, S., and Prada, D., "Prediction of Clean Octane Numbers of Catalytic Reformed Naphthas Using FT-MIR and PLS," Fuel, Vol. 76, 1997, pp. 1035-1042. [19 ] Meusinger, R., "Gasoline Analysis by 1H Nuclear Magnetic Resonance Spectroscopy," Fuel, Vol. 75, 1996, pp. 1235-1243. [20 ] deBakker, C. J. and Fredericks, P. M., "Determination of Petroleum Properties by Fiber-Optic Fourier Transform Raman Spectrometry and Partial Least-Squares Analysis," Applied Spectroscopy, Vol. 49, No. 12, 1995, pp. 1766-1771.

Analysis of Kerosine, Diesel, and Aviation Turbine Fuel by GregoryHemighaus Chromatographic Methods

INTRODUCTION

The first level of compositional information is group-type totals. ASTM Test Method D1319, Hydrocarbon Types in Liquid Petroleum Products by Fluorescent Indicator Adsorption, ~ gives volume percent saturates, olefins, and aromatics in materials that boil below 315°C (600°F). This covers jet fuels but not all diesel fuels, most of which have an end point above 315°C. Despite this limitation, the method has been used widely for diesel fuel due to the lack of a suitable alternative. In 1988 the California Air Resources Board issued regulations that limited the aromatic content of diesel fuel sold in California starting in 1993. This heightened awareness that ASTM D1319 was not appropriate for diesel fuels led to efforts being initiated though ASTM to develop a suitable alternative. This led to the development of ASTM Test Method D5186, Determination of the Aromatic Content and Polynuclear Aromatic Content of Diesel Fuels and Aviation Turbine Fuels by Supercritical Fluid Chromatography. 1 This method does not separate saturates and olefins, so it cannot be used as a replacement for ASTM D1319. Another complication in comparing the two methods is that ASTM D1319 gives results in volume-percent while ASTM D5186 results are in mass-percent. Another approach to the determination of aromatics in middle distillates is high performance liquid chromatography, (HPLC), with refractive index (RI) detection [2 ]. The Institute of Petroleum has standardized this technique as IP-391. ASTM is currently considering this method and may adopt it as a standard. HPLC with dielectric constant detection [3 ] was considered by ASTM, but problems with detector stability prevented standardization.

KEROSINE, DIESEL, AND AVIATIONturbine fuel (jet fuel) are members of the class of petroleum products known as middle distillates. As the name implies, these products are heavier than gasoline but lighter than gas oils. Middle distillates cover the boiling range from approximately 175°C to 375°C (350°F to 700°F) and the carbon number range from about Cs to C24. Besides these products, gas turbine fuel, fuel oil (heating oil), and some marine fuels are also classified as middle distillates because they have a wide boiling range that overlaps the lighter fuels. These products have similar properties but different specifications as appropriate for their intended use. Methods for determining physical properties of these products are well established. They are listed in Table 2 and most will not be discussed further. Table 2 also lists methods for elemental analysis of middle distillates. This chapter will focus on compositional analysis of these products. Because of the number of isomers in this carbon number range (see Table 3), complete speciation of individual hydrocarbons is not possible for middle distillates. Compositional analysis of middle distillates is obtained in terms of hydrocarbon group type totals. These groups are most often defined by a chromatographic separation or a mass spectral Z-series.

CURRENT

PRACTICES

Distillation One of the most important physical parameters defining these products is their boiling range distribution. Historically, this has been measured by ASTM Test Method D86, Distillation of Petroleum Products at Atmospheric Pressure. ASTM D86 is a low-efficiency, one theoretical plate distillation. This has been adequate for product specification purposes; however, engineering studies require true boiling point (TBP) data. TBP data can be provided by ASTM Test Method D2892, Distillation of Crude Petroleum (15-Theoretical Plate Column)J However, this method is rather difficult, time consuming, and expensive to run. TBP data are most often obtained using ASTM Test Method D2887, Boiling Range Distribution of Petroleum Fractions by Gas Chromatography ~ (simulated distillation). Use of simulated distillation has been recently reviewed [1 ].2

Coupled Chromatographic Techniques The combination of HPLC with GC can provide more detailed compositional information than either technique alone. Typically HPLC is used to separate a particular hydrocarbon group (saturates, mono-aromatics, di-aromatics) and transfer it to a high-resolution GC column that can resolve many of the individual compounds [4,5 ]. Supercritical fluid chromatography, (SFC), can be used instead of HPLC to make the primary separation [6 ]. These are rather sophisti2The italic face numbers in brackets refer to references at the end of this chapter.

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CHAPTER 3 - - A N A L Y S I S OF KEROSINE, DIESEL, AND AVIATION TURBINE FUEL cated techniques that are not yet suitable for routine analysis or standardization.

Spectrometric Methods Mass spectrometry has been a powerful technique for hydrocarbon-type analysis of middle distillates. It can provide more compositional detail than chromatographic analysis. Hydrocarbon types are classified in terms of a Z-series. Z in the empirical formula CnH2n+z is a measure of the hydrogen deficiency of the compound. ASTM Test Method D2425, Hydrocarbon Types in Middle Distillates by Mass Spectrometry/ determines eleven hydrocarbon types ranging from Z = + 2 (paraffins) to Z = - 18 (tticyclic aromatics). This method requires that the sample be separated into saturate and aromatic fractions before mass spectrometric analysis. This separation is standardized as ASTM Test Method D2549, Separation of Representative Aromatics and Nonaromatics Fractions of High-Boiling Oils by Elution Chromatography. I This separation is applicable to diesel fuel but not to jet fuel, since it is impossible to evaporate the solvent used in the separation without also losing the light ends of the jet fuel. Combined gas chromatography/mass spectrometry with Townsend discharge nitric oxide chemical ionization (TDNOCI GC/MS) has been used to give similar group-type results to ASTM D2425 but without pre-separation into saturates and aromatics [7 ]. In addition, this method can give the Z series information by carbon number showing how the composition changes with boiling point. Solid phase extraction followed by capillary GC/MS has been used for detailed analysis of aromatic hydrocarbons in diesel fuel [8 ]. The percentage of aromatic hydrogen atoms and aromatic carbon atoms can be determined by ASTM Test Method D5292, Aromatic Carbon Content of Hydrocarbon Oils by High Resolution Nuclear Magnetic Resonance Spectroscopy, ~ (NMR). Results from this test are not equivalent to mass- or volume-percent aromatics determined by the chromatographic methods. The chromatographic methods determine the mass- or volume-percentage of molecules that have one or more aromatic tings. Any alkyl substituents on the rings contribute to the percentage of aromatics determined by chromatographic techniques. ASTM D5292 gives the toolpercent of aromatic hydrogen or carbon atoms. NMR can also be used to determine mass-percent hydrogen in jet fuel by ASTM Test Method D3701, Hydrogen Content of Aviation Turbine Fuels by Low Resolution Nuclear Magnetic Resonance Spectrometry, 1 and in diesel fuels by ASTM Test Method D4808, Hydrogen Content of Light Distillates, Middle Distillates, Gas Oils, and Residua by Low Resolution Nuclear Magnetic Resonance Spectroscopy. ~ Naphthalene content is an important quality parameter of jet fuel. It can be determined by ASTM Test Method D1840, Naphthalene Hydrocarbons in Aviation Turbine Fuels by Ultraviolet Spectrophotometry. ~ This method uses an average absorptivity for C~0to C~3 naphthalenes so that two fuels with the same volume-percent naphthalenes but a different distribution of isomers could give different results.

23

Correlative Methods Correlative methods have long been used as a way of dealing with the complexity of petroleum fractions. Relatively easy to measure physical properties such as density, viscosity, and refractive index have been correlated to hydrocarbon composition. Several examples of this type of correlative methods are listed in Table 2. In recent years an entirely new class of correlative methods has been developed. These use near-infrared (NIR) or midinfrared spectra together with sophisticated chemometric techniques to predict a wide variety of properties. Properties such as saturates, aromatics, and freezing point of jet fuel [9 ] and density, viscosity, aromatics, heat of combustion, and cetane index of diesel fuel [10] have been successfully predicted. It is important to recognize that these methods are correlations and should not be used to estimate properties of fuels that are outside of the calibration set. There are currently no standard methods using these techniques that are applicable to middle distillates.

Non-Hydrocarbon Methods Although the focus of this book is hydrocarbon analysis, heteroatoms, mainly sulfur and nitrogen compounds, cannot be ignored. Methods for determining the concentration of these elements are well established and listed in Table 2. The combination of gas chromatography with element selective detection gives information about the distribution of the element. In addition, many individual heteroatomic compounds can be determined. Selective sulfur and nitrogen GC detectors, exemplified by the flame photometric detector (FPD) and the nitrogenphosphorus detector (NPD), have been available for many years. However, these detectors have limited selectivity for the element over carbon, exhibit non-uniform response, and have other problems that limit their usefulness. A new generation of element selective detectors has become available based on chemiluminescence and plasma emission spectroscopy that have excellent sensitivity, uniformity of response, and selectivity over carbon. Nitrogen compounds in middle distillates can be selectively detected by chemiluminescence [11 ]. Individual nitrogen compounds can be detected down to 100 ppb nitrogen. Gas chromatography with either sulfur chemiluminescence detection [12 ] or atomic emission detection [13 ] has been used for sulfur selective detection.

FUTURE TRENDS The trend toward more detailed compositional information is expected to continue. The combination of multiple chromatographic separations and spectroscopic detection is a very powerful approach to the analysis of complex petroleum fractions. The mass spectrometry group-type methods, including ASTM D2425, were developed on magnetic sector instruments that are no longer in use. ASTM is working on updat-

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MANUAL ON HYDROCARBON ANALYSIS

ing these methods to be used on m o d e r n quadrupole mass spectrometers. The ability to rapidly predict m a n y fuel properties suggests that the infrared/chemometric correlative techniques m a y find their best applications in on-line process control rather t h a n in the laboratory.

REFERENCES [1 ] Abbott, D.J., "Chromatography in the Petroleum Industry," Journal of Chromatography Library Series, E. R. Adlard, Ed., Vol. 56, 1995, Elsevier, New York. [2 ] Sink, C. W. and Hardy, D. R., "Quantification of Compound Classes in Complex Mixtures and Fuels Using HPLC with Differential Refractive Index Detection," Analytical Chemistry, Vol. 66, 1994, pp. 1334-1338. [3 ] Hayes, P. C., Jr. and Anderson, S. D., "The Analysis of Hydrocarbon Distillates for Group Types Using HPLC with Dielectric Constant Detection: A Review," Journal of Chromatographic Science, Vol. 26, 1988, pp. 210-217. [4 ] Trisciani, A. and Munari, F., "Characterization of Fuel Samples by On-Line LC-GC with Automatic Group-Type Separation of Hydrocarbons," Journal of High Resolution Chromatography, Vol. 17, 1994, pp. 452-456. [5 ] Kelly, G. W. and Bartle, K. D., "The Use of Combined LC-GC for the Analysis of Fuel Products: A Review," Journal of High Resolution Chromatography, Vol. 17, 1994, pp. 390-397. [6 ] Lynch, T. P. and Heyward, M. P., "Coupled Packed SFC and Capillary GC for the Quantitative Analysis of Complex Petro-

leum Fractions," Journal of Chromatographic Science, Vol. 32, 1994, pp. 534-540. [7 ] Dzidic, I., Petersen, H. A., Wadsworth, P. A., and Hart, H. V., "Townsend Discharge Nitric Oxide Chemical Ionization Gas Chromatography/Mass Spectrometry for Hydrocarbon Analysis of the Middle Distillates," Analytical Chemistry, Vol. 64, 1992, pp. 2227-2232. [8 ] Bundt, J. et al., "Structure-Type Separation of Diesel Fuels by Solid Phase Extraction and Identification of the Two- and Three-Ring Aromatics by Capillary GC-Mass Spectrometry," Journal of High Resolution Chromatography, Vol. 14, 1991, pp. 91-98. [9 ] Lysaght, M. A., Kelly, J. J., and Callis, J. B., "Rapid Spectroscopic Determination of Percent Saturates and Freezing Point of JP-4 Aviation Fuel," Fuel, Vol. 72, 1993, pp. 623-631. [10 ] Fodor, G.E. and Kohl, K. B., "Analysis of Middle Distillate Fuels by Midband Infrared Spectroscopy," Energy and Fuels, Vol. 7, 1993, pp. 598-601. [11 ] Chawha, B., "Speciation of Nitrogen Compounds in Gasoline and Diesel Range Process Streams by Capillary Column Gas Chromatography with Chemiluminescence Detection," Journal of Chromatographic Science, Vol. 35, 1997, pp. 97-104. [12 ] Kabe, T., Ishihara, A., and Tajima, H., "Hydrodesulfurization of Sulfur-Containing Polyaromatic Compounds in Light Oil," Industrial Engineering Chemistry Research, Vol. 31, 1992, pp. 1577-1580. [13] Hutte, R. S., "Chromatography in the Petroleum Industry," Journal of Chromatography Library Series, E. R. Adlard, Ed., Vol. 56, 1995, Elsevier, New York.

Analysis of Viscous Oils by Thomas M. Warne

range; those methods that are used to measure chemical composition such as elemental and molecular structure analysis; and derivative methods that correlate measured properties with aspects of chemical composition.

INTRODUCTION VISCOUSOILSare those petroleum fractions and derived products that have higher boiling points than distillate fuels and are liquid at, or slightly above, room temperature. They contain 20 to 50+ carbon atoms and distill at temperatures above 260°C (500°F). Examples include refinery streams such as gas oils and residuum, heavier fractions obtained from refining processes such as catalytic cracking, reforming, polymerization, solvent extraction, and hydro- and thermal cracking. Viscous oils include finished products such as lubricants, process oils, and insulating oils. Asphalt and coke are discussed only incidentally. These hydrocarbons are important commercially, providing both finished products for sale and feedstocks for further processing, primarily to fuels. The hydrocarbon composition of the viscous oils and the presence of heteroatoms and metals as contaminants or additives are the major determinant of the quality of finished products prepared from them. Detailed analysis of viscous oils is far more complex than the analysis of hydrocarbon gases and lower molecularweight liquids. The number of types of molecules present increases rapidly as the number of carbon atoms per molecule increases. Hydrocarbons in the viscous oil range are generally extremely complex mixtures. Characterization does not focus on identifying specific molecular structures, but on classes of molecules (paraffins, naphthenes, aromatics, polycyclic compounds, polar compounds, etc.). Besides complexity, analysis of viscous oils may be complicated by handling problems. The higher viscosity of the fluids makes them more difficult to sample and transfer. Many viscous oils have a very dark color, which causes problems with some test methods. Finally, besides carbon and hydrogen, high molecular weight fractions of crude oil often contain oxygen, sulfur, and nitrogen compounds; trace quantities of metals may also be present. Determining the chemical form present for these elements provides additional important information. Finished products made using viscous oils may contain additives or contaminants that also require analysis.

Physical Tests Density (Gravity) Density or relative density (specific gravity) is used whenever conversions must be made between mass (weight) and volume measurements. This property is often used in combination with other test results to predict oil quality. Five ASTM procedures for measuring density or gravity are generally applicable to measurements on viscous oils. ASTM Test Method D287, API Gravity of Crude Petroleum and Petroleum Products (Hydrometer Method)/ and ASTM Practice D1298, Density, Relative Density (Specific Gravity), or API Gravity of Crude Petroleum and Liquid Petroleum Products by Hydrometer Method, t use an immersed hydrometer for measurement. ASTM D287 is a special case of the hydrometer method that provides results as API gravity. Two other ASTM Test Methods, D1480, Density and Relative Density (Specific Gravity) of Viscous Materials by Bingham Pyncnometer, 2 and D1481, Density and Relative Density of Viscous Materials by Lipkin Bicapillary Pycnometer, 2 use a pycnometer to measure density or specific gravity and have the advantage of requiring a smaller sample size. Finally, ASTM Test Method D4052, Density and Relative Density of Liquids by Digital Density Meter 1 (and the related ASTM Test Method D5002, Density and Relative Density of Crude Oils by Digital Density Analyzer)/ measure density with a digital density analyzer. This device, which has gained wide acceptance, determines density by analysis of the change in oscillating frequency of a sample tube when filled with test oil. Viscous oils generally do not create problems because of sample volatility; however, all of the test methods are sensitive to the presence of gas bubbles in the fluid. With viscous oils, particular care must be taken to exclude or remove gas bubbles before measurement. With dark-colored samples, it may be difficult to determine whether all air bubbles have been eliminated.

C U R R E N T PRACTICES Test methods of interest for hydrocarbon analysis of viscous oils include tests that measure physical properties such as density, refractive index, molecular weight, and boiling

~Appears in this publication. 2Annual Book of ASTM Standards, Vol. 05.01.

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26

MANUAL ON HYDROCARBON ANALYSIS

Refractive Index Refractive index is the ratio of the velocity of light in air to the velocity of light in the measured substance. The numerical value of the refractive index varies inversely with the wavelength of light used and the temperature at which the measurements are taken. The refractive index of a substance is related to its chemical composition and may be used to draw conclusions about molecular structure. Two ASTM test methods are available for measuring the refractive index of viscous liquids. Both methods are limited to lighter-colored samples for best accuracy. Both methods were written for instruments which are no longer manufactured. ASTM Test Method D 1218, Refractive Index and Refractive Dispersion of Hydrocarbon Liquids/ is designed to use the Bausch & Lomb Precision Refractometer. This model is no longer manufactured. ASTM Test Method D 1747, Refractive Index of Viscous Materials,~ uses the Abbe type (Valentine) refractometer, which is no longer made. In both cases, other refractometers are available, but no cooperative work has been conducted to verify equivalence. There are also limitations on the availability of thermometers with suitable range and accuracy that will fit the instruments. ASTM Subcommittee D02.04.0D plans cooperative testing of modern commercial refractometers to develop precision data, but data are not yet available.

Molecular Weight Since viscous oils are commonly broad-boiling mixtures, measurements of molecular weight commonly provide massaverage or number-average measurements. A variety of methods are available. Molecular weight may be calculated from viscosity data using ASTM Test Method D2502, Estimation of Molecular Weight (Relative Molecular Mass) of Petroleum Oils from Viscosity Measurements. ~The current version requires centistoke viscosity at 100 and 210°F. The method is generally applicable to "average" petroleum fractions with molecular weight in the range 250 to 700. Samples with unusual composition, such as aromatic-free white mineral oils, or oils with very narrow boiling range, may give atypical results. For samples with higher molecular weight (up to 3000 or more) with unusual composition or for polymers, ASTM Test Method D2503, Relative Molecular Mass (Molecular Weight) of Hydrocarbons by Thermoelectric Measurement of Vapor Pressure, ~ is recommended. This method uses a vapor pressure osmometer to determine molecular weight. Low boiling samples may not be suitable if their vapor pressure interferes with the method. The method has only been standardized by ASTM for samples up to a molecular weight of 800. A third method is also available. ASTM Test Method D2878, Estimating Apparent Vapor Pressures and Molecular Weights of Lubricating Oils, ~ provides a procedure to calculate these properties from test data on evaporation. The procedure is based on ASTM Test Method D972, Evaporation Loss of Lubricating Greases and Oils.I The sample is partly evaporated at a temperature of 250 to 500°C; fluids not stable in this temperature range may require special treatment [1]. 3 3The italic numbers in brackets refer to the list of references at the end of this chapter.

Other approaches to determining molecular weight include distillation (gas chromatography) and mass spectroscopy. These are discussed separately.

Distillation Four distillation methods are in common use for determining the boiling range and for collecting fractions from viscous oils. ASTM Test Method D1160, Distillation of Petroleum Products at Reduced Pressure, 1 is probably the best known and most widely used of the methods for distillation of higherboiling petroleum products. The method is a vacuum distillation, applicable to samples that can be at least partially volatilized at temperature up to 400°C and pressure in the range 1 to 50 mm Hg. The distillation temperature at vacuum is converted to atmospheric equivalent temperatures. ASTM Test Method D447, Distillation of Plant Spray Oils/ is a method designed for characterization of these narrowboiling fractions. (Optimal persistence with minimal damage to plant fruit and foliage is obtained when narrow boiling petroleum fractions of appropriate volatility are used.) ASTM Test Method D2892, Distillation of Crude Petroleum (15-Theoretical Plate Column)/ applies to a wide range of products. The procedure uses a column with 15 theoretical plates and a 5"1 reflux ratio. The distillation is started at atmospheric pressure until the vapor temperature reaches 210°C. Distillation is continued at vacuum (100 mm Hg) until the vapor temperature again reaches 210°C or cracking is observed. With very heavy crudes or viscous products, a preferred alternate distillation method is ASTM Test Method D5236, Distillation of Heavy Hydrocarbon Mixtures (Vacuum Potstill Method). 1 This method should be used instead of ASTM D2892 for heavy crudes above a 400°C cutpoint. Unless a distillation method is required by specification or the collected fractions are needed for further testing, gas chromatographic methods have become preferred for determining the boiling range of petroleum fractions. ASTM Test Method D2887, Boiling Range Distribution of Petroleum Fractions by Gas Chromatography/ gives detailed information for samples with a final boiling point no higher than 538°C (1000°F) at atmospheric pressure and a boiling range greater than 55°C (100°F). Some laboratories have used modified procedures to analyze fractions boiling higher than 538°C. ASTM Subcommittee D02.04 has prepared a draft method that covers products boiling to 838°C; this method should be standardized in the near future.

Chemical Composition Elemental Analysis In elemental analysis of viscous oils, the analyst is most commonly interested in the presence of contaminant metals, nitrogen, and sulfur present in the hydrocarbon fraction. For finished products, additional information is sought regarding elements contributed by additives. While there exist many classical, wet chemical methods for determination of metals and certain elements, routine analysis generally involves instrumental methods based on spectrometric techniques including atomic absorption, emission, X-ray and plasma spectrometry.

C H A P T E R 4 - - A N A L Y S I S OF V I S C O U S O I L S Carbon and hydrogen are commonly determined by combustion analysis. There are numerous commercial instruments designed for this purpose. Generally, the sample is burned in an oxygen stream where carbon is converted to carbon dioxide and hydrogen to water. These compounds are absorbed and the composition is determined automatically from mass increase. Some instruments also measure nitrogen. ASTM Test Method D5291, Instrumental Determination of Carbon, Hydrogen and Nitrogen in Petroleum Products and Lubricants, 1 is a guide that summarizes general instructions to supplement manufacturers' instructions for their apparatus. It includes a list of recommended calibration standards for carbon, hydrogen, and nitrogen analyses.

Sulfur Sulfur is naturally present in many crude oils and petroleum fractions, most commonly as organic sulfides and heterocyclic compounds. Many refining steps aim to reduce this sulfur content to improve stability and reduce environmentally harmful emissions. Sulfur is also a component of wear-reducing and load-carrying additives, corrosion inhibitors, detergents, and emulsifiers. The methods used to measure sulfur content vary depending on the sulfur concentration, viscosity or boiling range, and presence of interfering elements. ASTM Test Method D129, Sulfur in Petroleum Products (General Bomb Method), 2 uses sample combustion in oxygen and conversion of the sulfur to barium sulfate, which is determined by mass. This method is suitable for samples containing 0.1 to 5.0 mass-% sulfur and can be used for most low-volatility petroleum products. Elements that produce residues insoluble in hydrochloric acid interfere with this method--this includes aluminum, calcium, iron, lead, and silicon, plus minerals such as asbestos, mica, and silica. For such samples, ASTM Test Method D1552, Sulfur in Petroleum Products (High Temperature Method), ~ is preferred. This method describes three procedures: the sample is first pyrolyzed in either an induction furnace or a resistance furnace; the sulfur is then converted to sulfur dioxide and either titrated with potassium iodate-starch reagent or the sulfur dioxide is analyzed by infrared spectroscopy. This method is generally suitable for samples containing from 0.06 to 8.0 mass-% sulfur and that distill at temperatures above 177°C. Two methods describe the use of X-ray techniques for sulfur determination. ASTM Test Method D2622, Sulfur in Petroleum Products by X-Ray Spectrometry, ~ can be used for samples with sulfur content of 0.001 to 5.0 mass-%. ASTM Test Method D4294, Sulfur in Petroleum Products by EnergyDispersive X-Ray Fluorescence Spectroscopy/ is useful at sulfur concentrations of 0.05 to 5.0 mass-%. Oil viscosity is not a critical factor with these two methods, but interference may affect test results when chlorine, phosphorus, heavy metals, and possibly silicon are present. For very low sulfur concentrations, a method that may be used is ASTM Test Method D4045, Sulfur in Petroleum Products by Hydrogenolysis and Rateometric Colorimetry? This is normally used for lower-viscosity fractions, but may be used for some viscous oils that boil below 371°C. The method is designed to measure sulfur in the range 0.02 to 10 mass-ppm.

27

Sulfur may also be determined along with metals by using ASTM Test Methods D4927, D4951, or D5185. These methods are described below under "Metals."

Nitrogen Nitrogen is present in viscous oils primarily as amines and heterocyclic ring compounds. Nitrogen is also a component of many additives used in petroleum products, including oxidation and corrosion inhibitors and dispersants. There are four ASTM standards describing analytical methods for nitrogen in viscous oils. ASTM Test Method D3228, Total Nitrogen in Lubricating Oils and Fuel Oils by Modified Kjeldahl Method, 4 is a standard wet chemical method. It is useful for determining the nitrogen content of most viscous oils in the range from 0.03 to 0.10 mass-%. The other three methods are instrumental techniques; one involves nitrogen reduction, the other two nitrogen oxidation. ASTM Test Method D3431, Trace Nitrogen in Liquid Petroleum Hydrocarbons (Microcoulometric Method), 5 is an instrumental method where nitrogen is pyrolyzed under reducing conditions and converted to ammonia, which is measured coulometrically. This method is very useful in assessing feeds for catalytic hydrogenation processes where nitrogen may act as a catalyst poison. ASTM Test Method D4629, Trace Nitrogen in Liquid Petroleum Hydrocarbons by Syringe/Inlet Oxidative Combustion and Chemiluminescence Detection/ is useful for samples containing 0.3 to 100 ppm nitrogen and boiling higher than 400°C but with viscosities of 10 cSt or less. Organic nitrogen is converted to NO and then to excited NO2 by reaction with oxygen and then ozone. Energy emitted during decay of the excited NO2 is measured with a photomultiplier tube. ASTM Test Method D5762, Nitrogen in Petroleum and Petroleum Products by Boat-Inlet Chemiluminescence, ~ is a complementary method suitable for more viscous samples that contain from 40 to 10,000 ppm nitrogen.

Metals The viscous fractions of crude oil often contain heavy metals such as iron, nickel, and vanadium. Catalytic refining processes are often sensitive to metal contamination and, therefore, the type and quantity of metals must be determined. In other cases such as lubricating oils, some metals are parts of compounds added to the petroleum component to enhance performance. Quantitative analysis for these metals is an important quality control step. ASTM Test Method D811, Chemical Analysis for Metals in New and Used Lubricating Oils, 6 is a standard wet cb_emical analysis method for aluminum, barium, calcium, magnesium, potassium, silicon, sodium, tin, and zinc. The procedure involves a series of chemical separations with specific elemental analysis performed using appropriate gravimetric or volumetric analyses. The method is very labor-intensive and is used primarily as a referee method or to calibrate standards for instrumental methods.

4Annual Book of ASTM Standards, Vol. 05.02. 5Discontinued; see 1993 Annual Book of ASTM Standards, Vol. 05.02. 6Discontinued; see 1989 Annual Book of ASTM Standards, Vol. 05.01.

28

MANUAL ON HYDROCARBON ANALYSIS

The most commonly used methods for determining metal content in viscous oils are spectroscopic techniques. Six ASTM standard methods exist that are applicable to viscous oils. Most methods permit simultaneous analysis of several elements; commercial instruments are readily available. Two use atomic absorption, one uses X-ray fluorescence, and three use inductively coupled plasma (ICP) spectroscopy. ASTM Test Method D4628, Analysis of Barium, Calcium, Magnesium and Zinc in Unused Lubricating Oils by Atomic Absorption Spectrometry, 1 is designed primarily for quality control analysis of additive metals in finished lubricants. The sample is diluted in kerosine and burned in an acetylenenitrous oxide flame of an AA spectrophotometer. The method is suitable for oils in the lubricating oil viscosity range. It is designed to measure barium at concentrations of 0.005 to 1.0 mass-%, calcium and magnesium at 0.002 to 0.3 mass-%, and zinc at 0.002 to 0.2 mass-%. Higher metal concentrations, such as are present in additives, can be determined by dilution. Lower concentrations in the range of 10 to 50 ppm can also be determined; however, the precision is poorer. An alternate test method is ASTM Test Method D4927, Elemental Analysis of Lubricant and Additive Components--Barium, Calcium, Phosphorus, Sulfur and Zinc by WavelengthDispersive X-Ray Fluorescence Spectroscopy. ~ The techniques are designed for unused lube oils containing metals at concentration levels from 0.03 to 1.0 mass-% and sulfur at 0.01 to 2.0 mass-%. Higher concentrations can be determined after dilution. A third technique is ASTM Test Method D4951, Determination of Additive Elements in Lubricating Oils by Inductively Coupled Plasma Atomic Emission Spectrometry (ICP/AES). 1 Determined elements are barium, boron, calcium, copper, magnesium, phosphorus, sulfur, and zinc in unused lubricating oils and additive packages. Elements can generally be determined at concentrations of 0.01 to 1.0 mass-%. The sample is diluted in mixed xylenes or other solvents containing an internal standard. ASTM Test Method D5185, Determination of Additive Elements, Wear Metals and Contaminants in Used Lubricating Oils and Determination of Selected Elements in Base Oils by Inductively Coupled Plasma Atomic Emission Spectrometry (ICP/AES),~ describes a modified ICP method. Although these methods are designed for used lubricating oils, they are also applicable to unused oils. Sensitivity and useable range varies from one element to another, but the method is generally applicable from 1 to 100 ppm for contaminants and up to 1000 to 9000 ppm for additive elements. The method covers: Additive Elements calcium magnesium phosphorus potassium sulfur zinc

aluminum barium boron chromium copper iron

Contaminant Elements lead sodium manganese tin molybdenum titanium nickel vanadium silicon silver

A third ICP method is ASTM Test Method D5708, Determination of Nickel, Vanadium and Iron in Crude Oils and Residual Fuels by Inductively Coupled Plasma (ICP) Atomic Emission Spectrometry. I Two procedures are described whereby the sample is either treated with acid to decompose

the organic material and dissolve the metals or, alternatively, the sample is dissolved in an organic solvent. The second procedure measures oil-soluble metals only and not insoluble particles. This inability to accurately measure metals in larger particles is true for many related methods. The method is sensitive down to about 1 ppm; the precision statement is based on samples containing i to 10 ppm iron, 10 to 100 ppm nickel, or 50 to 500 ppm vanadium. Finally, a second method provides an alternate method for analysis of crude oils and residuum: ASTM Test Method D5863, Determination of Nickel, Vanadium, Iron and Sodium in Crude Oils and Residual Fuels by Flame Atomic Absorption Spectrometry. 1 Pretreatment and limitations on determination of insoluble materials are identical to ASTM D5708. The sensitivity range is 3.0 to 10 ppm for iron, 0.5 to 100 ppm for nickel, 0.1 to 20 ppm for sodium, and 0.5 to 500 ppm for vanadium. Higher concentrations may be determined after dilution.

Miscellaneous E l e m e n t s Chlorine is present in some metalworking fluids as a chlorinated hydrocarbon or ester. It is less common in other viscous oils, but may be present in crude oils from brine contamination. Chlorine in lubricating oils can be determined using ASTM Test Method D808, Chlorine in New and Used Petroleum Products (Bomb Method), 2 or ASTM Test Method D1317, Chlorine in New and Used Lubricants (Sodium Alcoholate Method). 7 A rapid test method suitable for analysis of samples by non-technical personnel is ASTM Test Method D5384, Chlorine in Used Petroleum Products (Field Test Kit Method)? This method uses a commercial test kit where the oil sample is reacted with metallic sodium to convert organic halogens to halide, which is titrated with mercuric nitrate using diphenyl carbazone indicator. Iodides and bromides are reported as chloride. A special concern is contamination of viscous oils with polychlorinated biphenyls (PCBs). Electrical insulating oils require analysis before disposal to ensure the absence of PCBs. ASTM Test Method D6160, Determination of Polychlorinated Biphenyls (PCBs) in Waste Materials by Gas Chromatography, ~ is a newly introduced and widely applicable method. Standard reference samples for nine commercial PCBs (Aroclors) are available. Phosphorus is a common component of lubricating oil additives. It appears most commonly as a zinc dialkyl dithiophosphate or a tri-aryl phosphate ester, but other forms also occur. Two wet chemical methods are available. ASTM Test Method D1091, Test Methods for Phosphorus in Lubricating Oils and Additives, 2 describes an oxidation procedure that converts phosphorus to aqueous ortho-phosphate anion. This is then determined by mass as magnesium pyro-phosphate or photochemically as molybdi-vanadophosphoric acid. Phosphorus concentrations of 0.0002 to 20.0 mass-% can be accommodated by these procedures. An alternate test is ASTM Test Method D4047, Phosphorus in Lubricating Oils and Additives by Quinoline Phosphomolybdate Method. 4 Samples are oxidized to phosphate with zinc oxide, dissolved in acid, precipitated as quinoline phosphomolybdate, treated with excess standard alkali, and back-titrated with standard 7Discontinued; see 1994 Annual Book of ASTM Standards, Vol. 05.01.

CHAPTER 4--ANALYSIS OF VISCOUS OILS

29

acid. Both of these methods are primarily used for referee samples. Phosphorus is most commonly determined using X-ray fluorescence or ICP by ASTM Test Methods D4927 or D4951, which have been described previously under Metals.

mixture during processing. They are less reliable when comparing materials of different origin and can be very misleading when applied to atypical or unusual compositions.

Hydrocarbon Structure

A major use for gas chromatography for hydrocarbon analysis has been simulated distillation, as discussed previously. Other gas chromatographic methods have been developed for contaminant analysis. These include: ASTM Test Methods D3524, Diesel Fuel Diluent in Used Diesel Engine Oils by Gas Chromatography,1 and D4291, Trace Ethylene Glycol in Used Engine Oil. Column chromatography is used for several hydrocarbon type analyses that involve fractionation of viscous oils. Examples are: ASTM Test Methods D2007, Characteristic Groups in Rubber Extender and Processing Oils and Other Petroleum-Derived Oils by the Clay-Gel Absorption Chromatographic Method/ and D2549, Separation of Representative Aromatics and Nonaromatics Fractions of High-Boiling Oils by Elution Chromatography.~ ASTM D2007 uses absorption on clay and clay-silica gel, followed by elution of the clay with pentane to separate saturates; elution of clay with acetonetoluene to separate polar compounds; and elution of the silica gel fraction with toluene to separate aromatic compounds. ASTM D2549 uses absorption on a bauxite-silica gel column. Saturates are eluted with pentane; aromatics are eluted with ether, chloroform, and ethanol. A new method for hydrocarbon type analysis using supercritical fluid chromatography is under development by ASTM Subcommittee D02.04 and should be available shortly. Several promising chromatographic techniques have been reported for the analysis of lubricant base oils. Rod thin layer chromatography (TLC), high-performance liquid chromatography (HPLC), and supercritical fluid chromatography (SFC) have all been used for base oil analysis and base oil content [3-6 ]. Work to develop test methods is underway. Chromatographic methods are also extremely useful for isolation and identification of lubricant additives. Some recent papers reporting these techniques are available [7-9 ]. These methods have not yet been developed as standardized procedures.

Compositional analysis is concerned with determining structural relationships in the molecules present in a sample. Infrared spectroscopy is the most commonly used tool for qualitative chemical analysis of viscous oils. Descriptions and tables of characteristic absorbance for a variety of organic functional groups are readily available in many textbooks. Techniques for quantitative analysis for many additives and some hydrocarbon types are available, although few have been issued as ASTM standards. Reports on new methods are commonly reported in the chemistry literature. To locate information on new analytical methods, a most useful reference is the bi-annual Application Review published by the American Chemical Society. These have appeared recently in the June 15 issue of Analytical Chemistry in odd-numbered years. Recent reviews cover coal, crude oil, shale oil, heavy oils (natural and refined), lubricants, natural gas, and refined products and source rocks. Extensive references to original research papers are provided. A complimentary Fundamental Review covering the basic analytical techniques is published in even-numbered years. This review will emphasize those methods standardized by ASTM or under study within the committee.

Correlative Methods Correlative methods are derived relationships between fundamental chemical properties of a substance and measured physical or chemical properties. They provide information about an oil from readily measured properties. Examples of correlative methods of use with viscous oils are: ASTM Test Methods D2140, Carbon Type Composition of Insulating Oils of Petroleum Origin; a D2501, Calculation of Viscosity-Gravity Constant (VGC) of Petroleum Oils; ~D2502, Estimation of Molecular Weight (Relative Molecular Mass) of Petroleum Oils from Viscosity Measurements; ~ and D3238, Calculation of Carbon Distribution and Structural Analysis of Petroleum Analysis by the n-d-M Method. 4 D2501 describes the calculation of the viscosity-gravity coefficient. The VGC is a parameter derived from kinematic viscosity and density that has been found [2 ] to relate to the saturate/aromatic composition. D2502 permits estimation of molecular weight from kinematic viscosity measurements. This can be used with other properties to characterize hydrocarbon mixtures. ASTM D2140 and D3238 use correlations between the viscosity-gravity coefficient (or molecular weight and density) and refractive index to calculate carbon type composition in percent of aromatic, naphthenic, and paraffinic carbon atoms and an estimate of the number of aromatic and naphthenic rings present. Data from correlative methods must not be confused with more fundamental measurements obtained by chromatography or mass spectroscopy. Correlative methods can be extremely useful when used to follow changes in a hydrocarbon

8Annual Book of ASTM Standards, Vol. 10.03.

Chromatography

Spectrometric Methods Perhaps the most commonly used spectrometric method for analysis of viscous oils is infrared spectroscopy. General instructions for qualitative hydrocarbon type and functional group analysis are widely available. Papers have also been published for quantitative analysis of hydrocarbon types [10]. FT-IR techniques have been reported for use in predictive maintenance programs to monitor the concentration of additives and degradation products in used oils [11 ]. Two methods have been standardized using NMR for hydrocarbon characterization. An alternative to ASTM D5291 for determining hydrogen content of viscous oils is ASTM Test Method D4808, Hydrogen Content of Light Distillates, Middle Distillates, Gas Oils and Residua by Low Resolution Nuclear Magnetic Resonance Spectroscopy? The NMR method is simpler and more precise than techniques previously described in ASTM D5291. Procedures are described that cover light distillates with a 15 to 260°C boiling range, middle distillates and gas oils with boiling ranges of 200 to 370°C and 370 to 510°C, and residuum boiling above 510°C.

30

MANUAL ON H YD R O C A R B O N A N A L Y S I S

ASTM Test M e t h o d D5292, A r o m a t i c C a r b o n Contents of H y d r o c a r b o n Oils b y High Resolution N u c l e a r Magnetic Reso n a n c e Spectroscopy, 1 p e r m i t s d e t e r m i n a t i o n of a r o m a t i c h y d r o g e n a n d a r o m a t i c c a r b o n content of gas oils, lubricating oils, a n d other h y d r o c a r b o n fractions that are completely soluble in c h l o r o f o r m a n d c a r b o n t e t r a c h l o r i d e at a m b i e n t t e m p e r a t u r e s . Concentrations as low as 0.1 mol-% h y d r o g e n a n d 0.5 mol-% c a r b o n can be d e t e r m i n e d . Olefins a n d p h e n o lic c o m p o u n d s above 1 mass-% interfere. ASTM C o m m i t t e e D02 has s t a n d a r d i z e d three m e t h o d s for h y d r o c a r b o n c o m p o s i t i o n a l analysis using m a s s spectrometry. One of these is ASTM Test M e t h o d D2786, H y d r o c a r b o n Types Analysis of Gas-Oil S a t u r a t e s F r a c t i o n s by High Ionizing Voltage Mass S p e c t r o m e t r y ? A c o m p l e m e n t a r y m e t h o d is ASTM Test M e t h o d D3239, A r o m a t i c Types Analysis of Gas-Oil Aromatic F r a c t i o n s by High Ionizing Voltage Mass Spectrometry.1 These m e t h o d s require p r e l i m i n a r y sepa r a t i o n using elution c h r o m a t o g r a p h y , ASTM D2549, or similar method. A third m e t h o d , ASTM Test Method D2425, H y d r o c a r b o n Types in Middle Distillates by Mass Spectromet r y / m a y be applicable to s o m e viscous oil samples in the lower m o l e c u l a r weight range. The p r o c e d u r e s used in these m e t h o d s were originally developed a n d r e p o r t e d in 1969 [12 ]. They were developed using the Consolidated E l e c t r o d y n a m i c s Corp. Type 103 series (Model 21-100 a n d later the DuPont 21-103 a n d 21-104 instruments). These i n s t r u m e n t s are no longer in production. While n e w e r i n s t r u m e n t s are r e p o r t e d to give satisfactory results, the p r o c e d u r e s for their use have not been s t a n d a r d ized. Efforts are now in progress to provide test m e t h o d s using newer, lower-cost instruments. The use of q u a d r u p o l e i n s t r u m e n t s a n d a c o m b i n a t i o n of m a s s spectroscopy with gas or liquid c h r o m a t o g r a p h y should p r o d u c e useful new procedures.

FUTURE TRENDS As n o t e d in previous editions, the t r e n d in h y d r o c a r b o n analysis is away from m a n u a l test m e t h o d s a n d increasingly favors a u t o m a t e d i n s t r u m e n t a l methods. C o m m e r c i a l instrum e n t s are available that will p e r f o r m m a n y of the p r o c e d u r e s d e s c r i b e d in this chapter. While ASTM c o m m i t t e e s have stand a r d i z e d tests b a s e d on s o m e of these instruments, c o m m e r cial d e v e l o p m e n t is r a p i d a n d new analytical i n s t r u m e n t s are

constantly available. This t r e n d is expected to continue. A m a j o r challenge is to m a t c h s t a n d a r d test m e t h o d s with new e q u i p m e n t so that m e t h o d s do not b e c o m e obsolete. C o m b i n i n g s e p a r a t i o n a n d analysis techniques (hyphena t e d techniques) can p r o d u c e powerful tools for characterizing viscous oils. Thus, liquid c h r o m a t o g r a p h y o r gas c h r o m a t o g r a p h y can be used to s e p a r a t e a s a m p l e for subsequent c h a r a c t e r i z a t i o n by m a s s s p e c t r o m e t r y (LC/MS o r GC/MS). Research into suitable m e t h o d s for the analysis of viscous oils is underway, b u t no s t a n d a r d tests have yet b e e n prepared. Extensive r e s e a r c h on b o t h p r o t o n a n d carbon-13 nuclear m a g n e t i c r e s o n a n c e s p e c t r o s c o p y shows p r o m i s e as a tool for the analysis of lubricant base oils and other viscous oils. Both n e a r - i n f r a r e d spectroscopy (NIR) a n d F o u r i e r - t r a n s f o r m IR (FTIR) are the subjects of active research into m e t h o d s to characterize h y d r o c a r b o n s a n d for quality control d u r i n g p r o d u c t i o n of p e t r o l e u m products. S t a n d a r d test m e t h o d s using these techniques should b e c o m e available in the future.

REFERENCES [1 ] Coburn, J. F, "Lubricant Vapor Pressure Derived From Evaporation Loss," Transactions, American Society of Lubricating Engineers, ASLTA, Vol. 12, 1969, pp. 129-134. [2 ] Coats, H. B. and Hill, J. B., Industrial & Engineering Chemist~, Vol. 20, 1928, p. 641. [3 ] Barman, B. N., Journal of Chromatographic Science, Vol. 34, No. 5, 1996, pp. 219-225. [4 ] Sassiat, P. et al., Anal. Chim. Acta, Vol. 306, No. 1, 1995, pp. 73-79. [5 ] Kagdiyal, R. et al., Proceedings, Adv. Prod. Appl. Lube Base Stocks, 1994, pp. 295-302. [6 ] Jain, M. C. et al., Adv. Prod. Appl. Lube Base Stocks, 1994, pp. 272-279. [7] Hui, R. and Rosset, R.,Anal. Chim. Acta, Vol. 314, No. 3, 1995, pp. 1650-1657. [8 ] Machtalere, G. et al., Anal. Chim. Acta, Vol. 322, Nos. 1-2, 1996, pp. 31-41. [9 ] Lambroupoulos, N. et al., Journal of Chromatography, Vol. 749, Nos. 1-2, 1996, pp. 87-94. [10 ] Brandes, G., Brennstoff-Chemie, Vol. 37, 1956; Erdol und Kohle, Vol. 11, No. 10, 1958. [11 ] Powell, J. R. and Compton, D. A. C., Lub Eng., Vol. 49, No. 3, 1993, pp. 233-239. [12 ] Robinson, C. J. and Cook, G. L., Analytical Chemistry A, Vol. 41, 1969, p. 1548 ft.

Analysis of Waxes by Arthur D. Barker

INTRODUC~ON

ASTM Test Method D4419, Measurement of Transition Temperatures of Petroleum Waxes by Differential Scanning Calorimetry, 2 was produced in 1984 as a more accurate means of evaluating the melt characteristics of a wax. In the 1980s, ASTM D02.04 developed a gas chromatographic method, originally intended for the analysis of wax blends used in the rubber industry'. However, by the time the method was published, in 1993, the scope of the method had changed to ASTM Test Method D5442, Analysis of Petroleum Waxes by Gas Chromatography. 2 More recent innovations in nuclear magnetic resonance (NMR) instrumentation for measuring the oil content of waxes has led to the possibility of an alternative test to replace the lengthy ASTM Test Methods D721, Oil Content of Petroleum Waxes, 2 and D3235, Solvent Extractables in Petroleum Waxes. 2

PETROLEUM WAXES are the solid hydrocarbon residues remaining at the end of the refining process either in the lube stream (as mainly paraffin and intermediate waxes) or in the residual lube stock "tank bottoms" (as higher melting microcrystalline waxes). The waxy oil is fractionated to produce an oily wax, called slackwax. This is separated by solvent extraction and fractionated into different melting point ranges to give waxes with a variety of physical characteristics. Paraffin waxes consist mainly of straight chain alkanes (also called normal alkanes), with small amounts (3 to 15%) of branched chain alkanes (or iso-alkanes), cycloalkanes, and aromatics. Microcrystalline waxes contain high levels of branched chain alkanes (up to 50%) and cycloalkanes, particularly in the upper end of the molecular weight distribution. Paraffin waxes contain alkanes up to approximately 600 molecular weight, whereas microcrystalline waxes can contain alkanes up to 1100 molecular weight. Today refinery crude oils tend to be purchased from a variety of sources, which leads to variations in the wax products from the lube stream. Also paraffin and microcrystalline waxes have a large range of uses, either singly or as blends, or blended with other polymers. Therefore there is a need to characterize the refinery waxes, blended waxes, and end-user products. The main problems in characterizing waxes arise from the solid nature of the material and the difficulty in separating the material into its components, particularly in the case of microcrystalline waxes.

Gas Liquid Chromatography The separation of waxes on packed columns has been carried out since the 1960s [2,3 ], and capillary column chromatography was used in 1970 to separate a microcrystalline wax up to carbon chain length (also known as carbon number) n-Csa [4]. In the early 1980s, tire manufacturers requested ASTM D02.04 to produce a capillary column gas chromatography method to analyze rubber waxes (with oil content of less than 10%) from carbon number n-C~7 to n-C44. ASTM D02.10, the Subcommittee on Petroleum Wax, was asked by D02.04 to carry out the development of the method. By the time ASTM D5442 was issued, the scope of the method had been changed to encompass all petroleumderived waxes, including blends of waxes, from n-C17 to n-C44 using an n-Cl~ internal standard. The sample is diluted in a suitable solvent (cyclohexane is suggested), containing the n-C~6 internal standard. It is then injected into a capillary column, meeting a specified resolution, and the components are detected using a flame ionization detector. The eluted components are identified by comparison to a standard mixture containing every fourth alkane from n-Ct6 to n-C44. The resulting chromatogram is complex, and the area of each straight chain and branched chain alkane must be measured using a programmable integrator or computer chromatography software. ASTM Method D5442 outlines a complex procedure for measuring the amount of each n-alkane and associated iso-alkanes, which is difficult to carry out in an accurate manner. Immediately after the issuance of D5442, it was realized that the Scope of the method (alkanes from n-CI 7 to n-C44) was applicable only to the analysis of paraffin waxes, exclud-

CURRENT PRACTICES Analytical methods for waxes were originally based on physical tests, which are clearly explained in the ASTM Manual on Significance of Tests for Petroleum Products [1 ].1 Waxes are traded on the basis of the melting point range (e.g., 130 to 135°F melting point) as defined by ASTM Test Methods D87, Melting Point of Petroleum Wax (Cooling Curve), 2 or D127, Drop Melting Point of Petroleum Wax Including Petrolatum. 2 The growth in the reliability of sophisticated instrumentation has coincided with the need by wax blenders and users for more detailed "fingerprinting" of materials to obtain more precise quality control and detailed information. ~The italic numbers in brackets refer to references at the end of this chapter. 2Appears in this publication. 31

32 MANUAL ON H Y D R O C A R B O N A N A L Y S I S ing h i g h e r c a r b o n n u m b e r waxes. The availability of n-Cs0 a n d n-C60 s t a n d a r d s enables the m e t h o d to be extended to m i c r o c r y s t a l l i n e waxes. Also, the existing m e t h o d does not (1) take into account r e s e a r c h w o r k c a r r i e d out in the later p a r t of the 1980s on the effect of different integration methods that w o u l d result in i m p r o v e d a c c u r a c y of wax c h r o m a t o g r a p h y results a n d (2) include the use of p r o g r a m m a b l e t e m p e r a t u r e v a p o r i z e r (PTV) injectors [5,6]. The accurate quantitative analysis of microcrystalline waxes up to n-CT0 using the PTV injector was further amplified by Ludwig [7 ] in 1995 (30 years after his original p a p e r on w a x c h r o m a t o g r a p h y [3 ]). A review of the m e t h o d has t a k e n place, a n d it is h o p e d that a new r o u n d - r o b i n evaluation can be c a r r i e d out before the next revision of D5442 to validate (1) the use of the PTV injector, (2) use of the n-Cs0 a n d n-C60 standards, a n d (3) substitution of a new s i m p l e r calculation methodology.

An N M R m e t h o d has n o w b e e n developed, in conjunction with Oxford I n s t r u m e n t s , as a suitable alternative to ASTM Methods D721 a n d D3235. The N M R m e t h o d provides a r a p i d d e t e r m i n a t i o n of oil content, a unified m e t h o d for all wax oil content/solvent extractables analysis (covering the r a n g e 0.2 to 35% oil content), the exclusion of hot solvents, a n d it is easy to analyze the oil c o n t e n t of microcrystalline waxes. The c a l i b r a t i o n for this m e t h o d can n o w be c o m p a r e d with the present ASTM D721 b y using the LGC3004, 0.54% oil in wax s t a n d a r d CRM. A p r o p o s e d draft ASTM m e t h o d is being written for circulation a m o n g i n s t r u m e n t m a n u f a c t u r ers a n d users. It is h o p e d that the final draft will be jointed with the Institute of P e t r o l e u m a n d other s t a n d a r d i z a t i o n bodies so that a n i n t e r n a t i o n a l r o u n d r o b i n test can be carried out with sufficient participants.

FUTURE TRENDS

Oil Content Analysis During wax refining, increasing a m o u n t s of oil are removed, a n d this process needs to be controlled. Also, the oil content of slackwaxes, petrolatum, a n d waxes m u s t be assessed for end user specification. F o r high oil content waxes (i.e., greater t h a n 15%), ASTM Test M e t h o d D3235 was devised. This m e t h o d involves a lengthy p r o c e d u r e of dissolving a weighed a m o u n t of wax in a mixture of methyl ethyl ketone (MEK) a n d toluene, followed b y cooling to - 32°C to precipitate the wax. The oil a n d solvent are removed; then the solvent is e v a p o r a t e d off to p r o d u c e a weighable a m o u n t of oil. GLC analysis of the solvent-extracted m a t e r i a l has shown that the d e t e r m i n e d "oil" contains a small a m o u n t of additional wax, Y/-CI7to r/-C22 alkanes, t h e r e b y p r o d u c i n g a small error. ASTM Test M e t h o d D721 was devised for waxes containing less t h a n 15% oil. It is used in the specification of food-contact a p p r o v e d waxes a n d for waxes used in explosives. This m e t h o d is similar to ASTM D3235, b u t uses only M E K as the solvent. Both m e t h o d s take over half a day to complete, are l a b o r intensive, p r o d u c e variable results, a n d c a n n o t easily be used to analyze the oil content of microcrystalline waxes. This is not very useful for refinery process control, n o r for the analysis of wax m a t e r i a l s used in food-contact applications, etc. Refineries have o v e r c o m e this lengthy p r o c e d u r e by using various n u c l e a r m a g n e t i c r e s o n a n c e (NMR) techniques, calib r a t e d using waxes analyzed by either ASTM D721 o r D3235. In 1997 the UK L a b o r a t o r y of the G o v e r n m e n t Chemist (LGC) p r o d u c e d a wax certified reference m a t e r i a l with an oil content of 0.54% (Reference CRM:LGC 3004) [8]. This is useful as a n analytical quality control s t a n d a r d a n d overcomes the p r o b l e m of i n t e r l a b o r a t o r y disputes. Over the p a s t three years there has been a growing interest in the use of pulse NMR for the analysis of waxes for oil content. This technique relies on the fact that, after a wax has experienced a pulse of r a d i o - f r e q u e n c y radiation, the signals received f r o m the solid a n d liquid phases decay at different rates a n d that the a m p l i t u d e of each signal is p r o p o r t i o n a l to each p h a s e present. The solid signal decays r a p i d l y whereas the liqu!d signal lasts m u c h longer. The s a m p l e is cooled so that the wax is totally solid a n d the liquid signal is p r o p o r tional to the oil content.

In the next five years the p r o b l e m s associated w i t h the GLC analysis of waxes should be resolved, a n d there should be a n e w ASTM m e t h o d using N M R to m e a s u r e the oil content/ solvent extractables. Also, ASTM Test Method D4419 needs to be u p d a t e d a n d e x p a n d e d to i n c o r p o r a t e the m e a s u r e m e n t of wax enthalpy so t h a t the degree of crystallinity can be estimated. There also needs to be i m p r o v e m e n t s to ASTM Test M e t h o d D1833, Test M e t h o d for O d o r of Petroleum Wax, a w h i c h requires at least five people examining the o d o r of a wax u n d e r rigorous conditions. It is not a very practical test for small, m o d e r n laboratories. Solvent odors can be quantified by h e a d s p a c e GLC, but o t h e r odors, such as those due to oxidation, are m o r e complex a n d difficult to detect. F o r several years the possibility has b e e n explored of using a new type of i n s t r u m e n t a t i o n that consists of up of 32 sensors acting as an "electronic nose" to analyze h e a d s p a c e emissions. The responses from the multi-elements of the detector are complex a n d variable. Therefore, the electronic signals m u s t be processed as a neural network, a n d each a r o m a has to be "learned" by the software. These i n s t r u m e n t s are capable of m e a s u r i n g odors from individual waxes b u t will need further d e v e l o p m e n t to be of practical use for analyzing a variety of waxes. This example illustrates that there is still plenty of scope for the d e v e l o p m e n t of new m e t h o d s for the analysis of h y d r o c a r b o n s in waxes.

REFERENCES [1 ] Dyroff, G. V., Ed., Manual on Significance of Tests for Petroleum Products, Chap. 10, ASTM Manual Series MNL1, 6th ed., 1993. [2 ] Scott, C. G. and Rowel1, D. A., Nature, Vol. 187, 1960, p. 143. [3 ] Ludwig, F. J., Analytical Chemistry, Vol. 37, 1965, p. 1732. [4 ] Gouw, T. H., Whittemore, I. M., and Rentoft, R. E., Analytical Chemistry, Vol. 42, 1970, p. 1394. [5 ] Barker, A. D. in "Wax Chromatography--The 80's Crossroads," Petroanalysis '87, G. B. Crump, Ed., John Wiley & Sons Ltd., New York, 1988. [6 ] Barker, A. D., "The Chromatographic Analysis of Refined and Synthetic Waxes," Journal Chromatography Library, Vol. 56,

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C H A P T E R 5 - - A N A L Y S I S OF W A X E S Chromatography in the Petroleum Indust~, E. R. Adlard, Ed., Elsevier Science B.V., New York, 1995. [7 ] Ludwig, Sr., F. J., Journal of Chromatography A., Vol. 718, 1995, p. 119.

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[8 ] Petroleum Wax Oil Content CRM: Reference No. LGC 3004; Office of Reference Materials, Laboratory of the Government Chemist, Queens Road, Teddington, Middlesex, TW11 0LY, England.

Analysis of Crude Oils

6

by Axel J. Lubeck

INTRODUCTION

ently similar methods than are analyses on any single refined petroleum product except, possibly, gasoline. The overriding issue when performing comprehensive crude oil assays is economics. Crude oils are assayed to determine: (a) the slate of products that can be produced with a given refinery's process technology; (b) the processing difficulties that may arise as a result of inherent impurities; and (c) the downstream processing and upgrading that may be necessary to optimize yields of high-value, specification products. The analytical results are typically stored in an electronic database that can be accessed by computer models that generate refinery-specific economic valuations of each crude or crude slate (i.e., mixture of crudes processed together). Analyses are also performed to determine whether each batch of crude oil received at the refinery gate meets expectations. Does the crude receipt match the database assay so that the projected economic valuations and operational strategies are valid? Has any unintentional contamination or purposeful adulteration occurred during gathering, storage, or transport of the crude oil that may increase the processing cost or decrease the value of the refined products? The information needed to answer these questions is often refinery-specific--a function of the refinery's operating constraints and product slate. To obtain the desired information, two different analytical schemes are commonly used, namely, an inspection assay and a comprehensive assay. Inspection assays usually involve determination of a few key whole crude oil properties such as API gravity, sulfur content, and pour point--principally as a means of determining if major changes in a crude oil stream's characteristics have occurred since the last comprehensive assay was performed. Additional analyses may be performed to help ensure that the cargo or shipment received is that which is expected; to ascertain the quantity of impurities such as salt, sediment, and water; and to provide other critical refinery-specific information. Inspection assays are routinely performed on all shipments received at a refinery. The comprehensive assay, on the other hand, is complex, costly, and time-consuming and is normally performed only when a new field comes on stream, or when the inspection assay indicates that significant changes in the stream's composition have occurred. Except for these circumstances, a comprehensive assay of a particular crude oil stream may not be updated for several years.

CRUDE OILS are a highly complex combination of hydrocarbons; heterocyclic compounds of nitrogen, oxygen, and sulfur; organometallic compounds; inorganic sediment; and water. Approximately 600 different hydrocarbons have been identified in crude oil, and it is likely that thousands of compounds occur, many of which probably will never be identified. In a study sponsored by the American Petroleum Institute (API), nearly 300 individual hydrocarbons were identified in Ponca City, Oklahoma crude oil [1,2 ].2 Some 200 individual sulfur compounds were identified in a 20-year systematic study of four crude oils [3 ]. Not only is the composition of crude oil highly complex, it is also highly variable from field-to-field, and even within a given field it is likely to exhibit inhomogeneity. Physical and chemical characterization of this complex mixture is further complicated for the analyst by the fact that crude oils are not pure solutions, but commonly include colloidally suspended components, dispersed solids, and emulsified water. Compared to refined products such as gasoline and aviation turbine fuel, there is relatively little in the literature on the analysis and characterization of crude oils. Indeed, for many years, there were relatively few ASTM methods specific to crude oils, although a number of ASTM methods had been adapted for use in analyzing crudes. This situation may have resulted, at least in part, from the historical tendency of refinery chemists to independently develop or modify analytical methods specific to their needs and subsequently for the methods to become company proprietary. In recent years, the unique problems associated with sampling and analysis of crude oils have received more attention, and more methods for determining selected constituents and characteristics of crude oils are now being standardized. A series of articles [4-9 ] illustrate the diversity of crude oil assay practices employed by major refiners in the United States and Austria. The dissimilarity of results reported in the literature [10 ] is a reflection of this independent development of analytical schemes, even though standardized approaches to crude oil analysis have previously been published [11,12 ]. Despite the complexity of crude oil composition and the diversity of analytical methodology, probably more crude oil analyses are routinely performed on a daily basis using inher~This chapter is an updated and modified version of the chapter, authored by H. N. Giles, found in the previous edition of this manual. 2The italic numbers in brackets refer to the list of references at the end of this chapter. 34

CHAPTER 6 - - A N A L Y S I S OF CRUDE OILS

CURRENT PRACTICES Inspection Assays Inspection assays comprise a limited number of tests generally restricted to the whole crude oil. Based on published data, there is little agreement as to what constitutes an inspection assay. As the data are primarily for intra-company use, there is little driving force for a standard scheme. At a bare minimum, API gravity and sulfur content are usually determined, although it is useful to also know the pour point, which provides some basic perception of the crude oil's aromaticity. A more detailed inspection assay might consist of the following tests: API gravity (or density or relative density), total sulfur content, pour point, viscosity, salt content, and water and sediment content. Individual refiners may substitute or add tests (e.g., trace metals or organic halides) that may be critical to their operations. Coupling the results from these few tests of a current crude oil batch with the archived data from a comprehensive assay, the process engineer will be able to estimate generally the product slate that the crude will yield and any extraordinary processing problems that may be encountered.

API Gravity Accurate determination of the gravity of crude oil is necessary for the conversion of measured volumes to volumes at the standard temperature of 15.56°C (60°F) (ASTM D1250, Petroleum Measurement Tables). 3 Gravity is also a factor reflecting the quality of crude oils. API gravity is a special function of relative density (specific gravity) represented by the following: API gravity, deg -- (141.5/sp gr 60/60°F) - 131.5 API gravity, or density or relative density, can be determined easily using one of two hydrometer methods [ASTM Test Method D287, API Gravity of Crude Petroleum and Petroleum Products (Hydrometer Method) 3 or ASTM Test Method D1298, Density, Relative Density (Specific Gravity) or API Gravity of Crude Petroleum and Liquid Petroleum Products by Hydrometer Method ].3 An instrumental method that is finding increasing popularity (ASTM Test Method D5002, Density and Relative Density of Crude Oils by Digital Density Analyzer)3 may also be used.

35

a sample in oxygen to convert the sulfur to sulfur dioxide, which is collected and subsequently titrated iodometrically or detected by non-dispersive infrared [ASTM Test Method D1552, Sulfur in Petroleum Products (High-Temperature Method) ].3 An even older method involving combustion in a bomb with subsequent gravimetric determination of sulfur as barium sulfate [ASTM Test Method D129, Sulfur in Petroleum Products (General Bomb Method)]4 is not as accurate as the high-temperature method, possibly because of interference from the sediment inherently present in crude oil. The older, classical techniques are being supplanted by two instrumental methods (ASTM Test Method D4294, Sulfur in Petroleum Products by Energy-Dispersive X-Ray Fluorescence Spectroscopy and ASTM Test Method D2622, Sulfur in Petroleum Products by X-Ray Spectrometry). 3 D4294 has slightly better repeatability and reproducibility than the hightemperature method and is adaptable to field applications; however, this method can be affected by some commonly present interferences such as halides. D2622 has even better precision and the capability of correcting for interferences, but is currently limited to laboratory use, and the equipment is more expensive. Hydrogen sulfide and mercaptans are commonly determined by non-aqueous potentiometric titration with silver nitrate [13 ].

Salt Content The salt content of crude oil is highly variable and results principally from production practices used in the field and, to a lesser extent, from its handling aboard tankers bringing it to terminals. The bulk of the salt present will be dissolved in coexisting water and can be removed in desalters, but small amounts of salt may be dissolved in the crude oil itself. Salt may be derived from reservoir or formation waters, or from other waters used in secondary recovery operations. Aboard tankers, ballast water of varying salinity may also be a source of salt contamination. Salt in crude oil may be deleterious in several ways. Even in small concentrations, salts will accumulate in stills, heaters, and exchangers leading to fouling that requires expensive cleanup. More importantly, during flash vaporization of crude oil certain metallic salts can be hydrolyzed to hydrochloric acid according to the following reactions: 2NaC1 + H20--~ 2 HC1 + Na20

Sulfur Content The sulfur content of a crude oil, which may vary from less than 0.1 to over 5 mass-%, is one of its most important quality attributes. Sulfur compounds contribute to corrosion of refinery equipment and poisoning of catalysts, cause corrosiveness in refined products, and contribute to environmental pollution as a result of the combustion of fuel products. Sulfur compounds may be present throughout the boiling range of crude oils although, as a rule, they are more abundant in the heavier fractions. In some crude oils, thermallylabile sulfur compounds can decompose on heating to produce hydrogen sulfide that is highly toxic and very corrosive. Until recently, one of the most widely used methods for determination of total sulfur content has been combustion of 3Appears in this publication.

MgC12 + H20--* 2 HCI + MgO The hydrochloric acid evolved is extremely corrosive, necessitating the injection of a basic compound, such as ammonia, into the overhead lines to minimize corrosion damage. Salts and evolved acids can also contaminate both overhead and residual products, and certain metallic salts can deactivate catalysts. A thorough discussion of the effects of salt on crude processing is included in a manual on impurities in petroleum [14 ]. The salt content is routinely determined by comparing the conductivity of a solution of crude oil in a polar solvent to that of a series of standard salt solutions in the same solvent [ASTM Test Method D3230, Salts in Crude Oil (Electrometric

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MANUAL ON H YD R O C A R B O N A N A LYSI S

Method)]. 3 It is necessary, however, to employ other methods, such as atomic absorption, inductively-coupled argon plasma spectrophotometry, and ion-chromatography to determine the composition of the salts present.

Water and Sediment The water and sediment content of crude oil, like salt, results from production and transportation practices. Water, with its dissolved salts, may occur as easily removable suspended droplets or as an emulsion. The sediment dispersed in crude oil may be comprised of inorganic minerals from the production horizon or from drilling fluids, and scale and rust from pipelines and tanks used for oil transportation and storage. Usually water is present in far greater amounts than sediment but, collectively, it is unusual for them to exceed one percent of the crude oil on a delivered basis. Like salt, water and sediment can foul heaters, stills, and exchangers and can contribute to corrosion and to deleterious product quality. Also, water and sediment are principal components of the sludge that accumulates in storage tanks and must be disposed of periodically in an environmentally acceptable manner. Knowledge of the water and sediment content is also important in accurately determining net volumes of crude oil in sales, taxation, exchanges, and custody transfers. A number of methods exist for the determination of water and sediment in crude oil. Centrifugal separation of the water and sediment [ASTM Test Methods D96, Water and Sediment in Crude Oil by Centrifuge Method (Field Procedure) or D4007, Water and Sediment in Crude Oil by the Centrifuge Method (Laboratory Procedure)]a is rapid, relatively inexpensive, and adaptable to field conditions but, almost invariably, the amount of water detected is lower than the actual water content. A more accurate method for sediment entails extraction with hot toluene in a refractory thimble (ASTM Test Method D473, Sediment in Crude Oils and Fuels Oils by the Extraction Method).3 Improved techniques for measuring water content include heating under reflux conditions with a water immiscible solvent that distills as an azeotrope with the water (ASTM Test Method D4006, Water in Crude Oil by Distillation), 3 potentiometric titration (ASTM Test Method D4377, Water in Crude Oils by Potentiometric Karl Fischer Titration), 3 or the more generally preferred coulometric titration (ASTM Test Method D4928, Water in Crude Oils by Coulometric Karl Fischer Titration). 3 The latter two Karl Fischer methods include a homogenization step designed to re-disperse any water that has separated from the crude oil since the original sample was taken.

Pour Point and Viscosity Pour point and viscosity determinations of crude oils are performed principally to ascertain their handling characteristics at low temperatures. There are, however, some general relationships about crude oil composition that can be derived from pour point and viscosity data. Commonly, the lower the pour point of a crude oil the more aromatic it is, and the higher the pour point, the more paraffinic it is. There are numerous exceptions to this rule-of-thumb, and other data must be used to verify a crude oil's character. Probably the most widely used index is the Characterization or K Factor [15 ], which was originally defined as the cube root of the average molal boiling point in °F absolute (Rankine) tempera-

ture divided by the specific gravity, at 60/60°F. It has conveniently been related to viscosity and API gravity [16 ]. Typically, paraffin base crudes have K > 12.2, intermediate base crudes have K values of 11.4 to 12.2, and naphthene base crudes have K < 11.4 [17 ]. Pour point is determined by cooling a preheated sample at a specified rate and examining its flow characteristics at intervals of 3°C (ASTM Test Method D5853, Pour Point of Crude Oils). 3 Viscosity is determined by measuring the time for a volume of liquid to flow under gravity through a calibrated glass capillary viscometer [ASTM Test Method D445, Kinematic Viscosity of Transparent and Opaque Liquids (and the Calculation of Dynamic Viscosity)]. 3 Tables are available for converting kinematic viscosity in centistokes at any temperature to Sayholt Universal viscosity in Sayhoh Universal seconds at the same temperature, and for converting kinematic viscosity in centistokes at 122 and 210°F to Saybolt Furol viscosity in Saybolt Furol seconds at the same temperatures (ASTM Method D2161, Conversion of Kinematic Viscosity to Sayholt Universal Viscosity or to Saybolt Furol Viscosity). 4 By determining viscosity at two temperatures such as 25 and 37.78°C, viscosity at any other temperature over a limited range may be interpolated or extrapolated using viscosity-temperature charts (ASTM D341, Viscosity-Temperature Charts for Liquid Petroleum Products). 3

Trace Elements A number of trace elements have been detected in crude oil but, aside from nickel and vanadium, which are usually the most abundant, relatively little systematic analytical work has been carried out. Over 30 trace metals are known to occur naturally in crude oils [l&19] and, with the increasing sophistication of analytical methodology, it is likely that other elements will be detected. Knowledge of the trace element constituents is important because they can have an adverse effect on petroleum refining and product quality. Elements such as iron, arsenic, and lead are catalyst poisons. Vanadium compounds can cause refractory damage in furnaces, and sodium compounds have been found to cause superficial fusion on fire bricks [20 ]. Some organometallic compounds are volatile, which can lead to contamination of distillate fractions [21 ] and a reduction in their stability or malfunctions of equipment when they are combusted. Concentration of the non-volatile organometallics in heavy products (e.g., premium coke) can have a significant impact on price, salability, and use. Several analytical methods are available for the routine determination of trace elements in crude oil, some of which allow direct aspiration of the samples (diluted in a solvent) instead of the time-consuming sample preparation procedures such as wet ashing (acid decomposition) or flame or dry ashing (removal of volatile/combustible constituents). Among the techniques used for trace element determinations are flameless and flame atomic absorption (AA) spectrophotometry (ASTM Test Method D5863, Determination of Nickel, Vanadium, Iron, and Sodium in Crude Oils and Residual Fuels by Flame Atomic Absorption Spectrometry) 3 and inductively-coupled argon plasma spectrophotometry [ASTM Test Method D5708, Determination of Nickel, Vanadium, and Iron in Crude Oils and Residual Fuels by Inductively-Coupled Plasma (ICP) Atomic Emission Spectrometry]. 3 ICP has an

CHAPTER 6--ANALYSIS OF CRUDE OILS advantage over AA because it can determine a number of elements simultaneously, although detection limits by AA are often better. X-ray fluorescence spectrophotometry is also sometimes used, although matrix effects can be a problem. The method to be used is generally a matter of individual preference.

Other Tests Other properties that are determined on a more limited basis include the following:

Vapor Pressure--[ASTM Test Method D323, Vapor Pressure of Petroleum Products (Reid Method) or ASTM D5191, Vapor Pressure of Petroleum Products (Mini Method)]) Total Acid Number--to provide an indication of the naphthenic acids content (ASTM Test Method D664, Acid Number of Petroleum Products by Potentiometric Titration). 3 Carbon Residue--amount left after evaporation and pyrolysis to provide some indication of relative coke-forming propensity (ASTM Test Method D189, Conradson Carbon Residue of Petroleum Products, ASTM Test Method D524, Ramsbottom Carbon Residue of Petroleum Products, or ASTM Test Method D4530, Determination of Carbon Residue (Micro Method)), 3 ASTM Method D4530 having gained wide acceptance. Total Nitrogen Content--(ASTM Test Method D3228, Total Nitrogen in Lubricating Oils and Fuel Oils by Modified Kjeldahl Method), 5 (ASTM Test Method D4629, Trace Nitrogen in Liquid Petroleum Hydrocarbons by Syringe/ Inlet Oxidative Combustion and Chemiluminescence Detection, ASTM Test Method D5762, Nitrogen in Petroleum and Petroleum Products by Boat-Inlet Chemiluminescence)) Organic Chloride Content--by distillation and sodium biphenyl reduction or microcoulometry (ASTM Test Method D4929, Determination of Organic Chloride Content in Crude Oil). 3 Waxes and Asphaltenes--by solvent extraction; and determination of optical density color by spectrophotometrically measuring the absorbance of a solution of the crude oil in isooctane (2,2,4-trimethylpentane) or other suitable solvent. With increasing frequency, refinery engineers desire an estimate of the distillation yields of a crude oil. These can be provided rapidly, without the performance of a conventional pot distillation, using gas chromatography (ASTM Test Method D5307, Determination of the Boiling Range Distribution of Crude Petroleum by Gas Chromatography). 3 The inspection assay tests discussed above are undoubtedly not exhaustive, but are the ones most commonly used. These tests will provide the refiner with data on the impurities present and a general idea of the products that may be recoverable. However, they will not provide the data essential to determining whether a given crude oil or blend of crude oils will yield an economically attractive product slate. This requires that a comprehensive assay be performed.

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37

Comprehensive Assays In addition to the whole crude oil tests performed as part of the inspection assay, a comprehensive or full assay requires that the crude be fractionally distilled and the fractions characterized by appropriate tests. This is necessary so that the refiner can assess the quantity and quality of products recoverable from a given crude oil and determine if that product slate economically satisfies the market requirements of a particular refinery. Refiners tailor a comprehensive assay to their individual needs, and the number of cuts or fractions taken may vary from as few as 4 to as many as 24. The following eight fractions will provide the basis for a moderately thorough evaluation: C2-C5 C5-79°C 79-121°C 121-191°C 191-277°C 277-343°C 343-566°C 566°C +

Gas Light naphtha Medium naphtha Heavy naphtha Kerosine Distillate fuel oil Gas oil or lube stock Residuum

Commonly, from five to 50 L of crude oil will be needed for a comprehensive assay, depending on the number of cuts to be taken and the tests to be performed on the fractions. Fractionation of the crude oil begins with a true boiling point (TBP) distillation employing a fractionating column having an efficiency of 14 to 18 theoretical plates and operated at a reflux ratio of 5 : 1 [ASTM Test Method D2892, Distillation of Crude Petroleum (15-Theoretical Plate Column)]) The TBP distillation may be used for all fractions up to a maximum cut point of about 350°C atmospheric equivalent temperature (AET), provided reduced pressure is used to minimize cracking. Beyond an AET of 350°C, it is necessary to continue the distillation at further reduced pressures under conditions that provide approximately a one-theoretical plate fractionation (ASTM Test Method D1160, Distillation of Petroleum Products at Reduced Pressure). 3 This fractionation may be continued up to a maximum liquid temperature of approximately 400°C at a pressure of 0.13 kPa (1 mm Hg)(640°C AET) provided significant cracking does not occur. In 1992 a new standard was published [ASTM Test Method D5236, Distillation of Heavy Hydrocarbon Mixtures (Vacuum Potstill Method)]3 that is seeing increasingly more use and appears to be supplanting D 1160 as the method of choice for crude assay vacuum distillations. Wiped-wall or thin-film molecular stills can also be used to separate the higher boiling fractions under conditions that minimize cracking. In these units, however, cut points cannot be directly selected, because vapor temperature in the distillation column cannot be measured accurately under operating conditions. Instead, the wall (film) temperature, pressure, and feed rate that will produce a cut equivalent to a D 1160 (or D5236) fraction with a given end point are determined from in-house correlations developed by matching yields between the wiped-wall distillation and the D1160 (or D5236) distillation. Despite the indirect approach, wiped-wall stills are often used because they allow higher end points than the D1160 or D5236 test methods and can easily provide large quantities of material for characterization.

38

MANUAL ON HYDROCARBON ANALYSIS

Following fractionation of the crude oil, each of the fractions is analyzed to determine one or more of its physical or chemical characteristics depending on the needs of the refiner. All of the various tests that could be performed on each of the fractions are too numerous to be included here. In the following discussion, the properties or constituents generally measured in a detailed analysis of each of the above eight fractions are listed. Gas

Typically, the gas or debutanization fraction is analyzed by high-resolution gas chromatography for quantitative determination of individual C2 to C4 and total C5 ÷ hydrocarbons. Relative density (specific gravity) can be calculated from the compositional analysis.

Light Naphtha Density or specific gravity by hydrometer or (ASTM Test Method D4052, Density and Relative Density of Liquids by Digital Density Meter), 3 total sulfur (ASTM Test Method D2622, ASTM Test Method D3120, Trace Quantities of Sulfur in Light Liquid Petroleum Hydrocarbons by Oxidative Microcoulometry, or ASTM Test Method D5453, Determination of Total Sulfur in Light Hydrocarbons, Motor Fuels, and Oils by Ultraviolet Fluorescence), 3 mercaptan sulfur [ASTM Test Method D3227, Mercaptan Sulfur in Gasoline, Kerosine, Aviation Turbine, and Distillate Fuels (Potentiometric Method)], 3 hydrogen sulfide, and organic chlorides are typically determined on this fraction. Because this fraction is important both as a petrochemical feedstock and as a gasoline blending component, it is likely that it would also be analyzed by high-resolution gas chromatography for quantitative determination of its paraffin, isoparaffin, aromatic, naphthene (cycloparaffin), and olefin, if any, components (PIANO analysis). Octane numbers would also be determined for this fraction if it were to be included as a gasoline blending component. Typically, octane numbers are determined using special engines that require relatively large volumes of sample (ASTM Test Method D2699, Knock Characteristics of Motor Fuels by the Research Methods and ASTM Test Method D2700, Knock Characteristics of Motor and Aviation Fuels by the Motor Method). 6 Some companies are now using semi-micro methods that require considerably less sample than the above standard methods for determination of octane numbers [22 ]. Other laboratories use PIANO data to calculate octane numbers [5 ].

Medium and Heavy Naphthas Density or specific gravity, total sulfur, mercaptan sulfur, hydrogen sulfide, organic chloride, and PIANO determinations would normally be determined on these fractions. Included in the information that can be derived from the PIANO analysis are the concentrations of benzene and benzene precursors (compounds that ultimately form benzene in a refinery's reforming unit). These data are important because of governmental regulations limiting the maximum concentration of benzene in reformulated gasoline. 6Annual Book of ASTM Standards, Vol. 05.04.

Kerosine Typically, density or specific gravity, total sulfur, mercaptan sulfur, hydrogen sulfide, aniline point (ASTM Test Method D611, Aniline Point and Mixed Aniline Point of Petroleum Products and Hydrocarbon Solvents), 3 total acid or neutralization number, naphthalenes content (ASTM Test Method D 1840, Naphthalene Hydrocarbons in Aviation Turbine Fuels by UV Spectrophotometry), 3 smoke point (ASTM Test Method D1322, Smoke Point of Aviation Turbine Fuels), 3 total nitrogen (see Note 1), viscosity, and freezing point (ASTM Test Method D2386, Freezing Point of Aviation Fuels) 3 would be determined for this fraction and a cetane index calculated (ASTM Test Method D976, Calculated Cetane Index of Distillate Fuels or ASTM Test Method D4737 for Calculated Cetane Index by Four Variable Equation). 3 Other tests that might be performed, depending on the intended end use of the fraction, are flash point (ASTM Test Method D56, Flash Point by Tag Closed Tester), 3 corrosiveness (ASTM Method D130, Detection of Copper Corrosion from Petroleum Products by the Copper Strip Tarnish Test), 3 and thermal stability [ASTM Test Method D3241, Thermal Oxidation Stability of Aviation Turbine Fuels (JFTOT Procedure)] .3

Note 1--In general, the ratio of basic to total nitrogen is practically constant at 0.3:1 for crude oils and virgin stocks. It also appears that the types of nitrogen compounds present in various crude oils are essentially the same, although the actual amounts may vary considerably [23 ]. Consequently, in most assays it is sufficient to determine total nitrogen (by the modified Kjeldahl or chemiluminescence methods).

Distillate Fuel Oil Tests of the fuel oil fraction normally include determination of density or specific gravity, total sulfur, aniline point, total acid number, naphthalenes content, smoke point, total nitrogen, viscosity, cloud point (ASTM Test Method D2500, Cloud Point of Petroleum Oils), 3 pour point (ASTM Test Method D97, Pour Point of Petroleum Oils), 3 and calculation of cetane index. Corrosiveness, ash (ASTM Test Method D482, Ash from Petroleum Products), 3 and carbon residue might also be determined in more thorough evaluations.

Gas Oil and Lube Stocks Density or specific gravity, total sulfur, aniline point, total nitrogen, viscosity, cloud point, pour point, trace metals (Fe, Ni, V), and carbon residue would normally be determined on this fraction. If the fraction is to be used as catalytic cracker feedstock, asphaltenes would also be determined by precipitation with normal-heptane (ASTM Test Method D3279, Heptane Insolubles). 3 Wax content determination by solvent reflux [24 ] might be included in a lube stock evaluation. Hydrocarbon-type analysis by mass spectrometry or other means is an important part of lube stock evaluation, but this is beyond the scope of this chapter.

Residuum Tests of the residuum typically include density or specific gravity, total sulfur, total nitrogen, viscosity, trace metals, and carbon residue. Determination of the properties of asphalt such as penetration (ASTM Test Method D5, Penetra-

C H A P T E R 6 - - A N A L Y S I S OF C R U D E O I L S tion of Bituminous Materials), 3 softening point [ASTM Test Method D36, Softening Point of Bitumen (Ring-and-Ball Apparatus) ],3 and viscosity (ASTM Test Method D2171, Viscosity of Asphalts by Vacuum Capillary Viscometer or ASTM Test Method D3205, Viscosity of Asphalt with Cone and Plate Viscometer) 3 would also be included in some assays. However, new specifications for asphalt have been developed by the Strategic Highway Research Program (SHRP) and test methods are being standardized by the American Association of State Highway and Transportation Officials (AASHTO) and ASTM. These test methods will replace some of the existing asphalt test methods as states adopt the SHRP specifications. The tests listed for each fraction and for the whole crude oil assay are not exhaustive but are illustrative of those used to evaluate quality. A more thorough discussion [25 ] of the significance of many of the above tests, as well as methods for the assessment of product quality, is available. As noted earlier, refiners tailor their analytical scheme to their particular crude oil and product slates, although one refiner is reported to have said "The best crude oil assay is a 100,000 bbl run through my refinery" [26 ]. While this opinion carries some validity, the assay methods presented here provide quantity and quality data that are sufficient for most refiners to evaluate crude oil streams, and, in some instances, assay information is the ounce of prevention that precludes the need for a refinery to apply the pound of cure. With the proliferation of computer "assay" programs [9 ], many refiners no longer need to perform comprehensive assays as frequently as in the past. An inspection assay is all that is required for them to anticipate and plan for processing problems that will be caused by varying levels of impurities in the crude oil stream.

FUTURE TRENDS The crude oils being processed in refineries are on average becoming increasingly heavier (more residuum) and more sour (higher sulfur content). To produce a viable product slate with these crudes, refiners must add to or expand existing treatment and processing options. The high sulfur content of crude coupled with government regulations limiting the maximum sulfur content of fuels makes sulfur removal a priority in refinery processing. In addition, refinery economics dictate that the "bottom of the barrel" (residuum) must be upgraded to higher value products. New treatment and process units in the refinery usually translate into a need for new analytical test methods that can adequately evaluate feedstocks and monitor product quality. Sulfur reduction processes are sensitive to both amount and structure of the sulfur compounds being removed. Tests that can provide information about both are becoming increasingly important. A number of laboratories have combined the separation power of gas chromatography with sulfur-selective detectors to provide data on the boiling range distribution of the sulfur compounds and probable molecular types, as well. A method (ASTM Test Method D5623, Sulfur Compounds in Light Petroleum Liquids by Gas Chromatography and Sulfur Selective Detection) 3 has been standardized for sulfur compounds in the gasoline boiling range. Work on extending this type of analysis to higher boiling ranges is on-

39

going. In addition, gas chromatography detectors that provide selectivity for other constituents of interest (e.g., nitrogen, organometallics) are also available and being used for characterization. Upgrading the "bottom of the barrel" involves taking more (ideally all) of the residuum and processing it into a more salable, higher valued product. Whatever the means to this end, improved characterization methods are necessary for process design, crude oil evaluation, and operational control. Among the characterization methods under development by industry, instrument vendor, and commercial laboratories are ones that define the boiling range and the hydrocarbontype distribution. Boiling range distribution of heavy distillates and residua are increasingly being carried out by hightemperature simulated distillation (HTSD) by gas chromatography. An HTSD test method applicable to distillates with end points up to 700°C is currently in the balloting process as a proposed ASTM standard. A separate HTSD method is in use for residuum-containing materials, including crude oils [27 ]. This method provides a quantitative boiling range distribution (that accounts for non-eluting components) in a single analysis as opposed to two analyses required by D5307. However, the method has not yet been submitted to ASTM for standardization. The distributions of hydrocarbon types in gas oil and heavier materials are important in evaluating them as feedstocks for further processing. Some ASTM member laboratories are working to update older mass spectrometric methods for determining hydrocarbon types (ASTM Test Method D3239, Aromatic Types Analysis of Gas-Oil Aromatic Fractions by High Ionizing Voltage Mass Spectrometry and ASTM Test Method D2786, Hydrocarbon Types Analysis of Gas Oil Saturates Fractions by High Ionizing Voltage Mass Spectrometry) 3 for use with modern quadrupole mass spectrometers, either with batch inlets or with gas chromatographic inlets (GC/MS). Another technique that has been successfully applied for determining hydrocarbon types in these materials involves use of high-performance liquid chromatography [28]. Providing comparable information to the mass spectrometric methods, the HPLC method is yet to be submitted to ASTM for standardization. From the examples above, it is obvious that automated, instrumental analyses continue to be the option of choice when developing new methods. There is no indication that this propensity will wane. The primary motivation for this trend, if anything, is increasing. Labs are continually seeking to reduce analysis time (especially analyst's time) and improve the quality of test results (in these cases by eliminating dependency on the manual skills of the analyst). Fueled by rapid advances in technology, more of the same is expected as the analytical challenges of the industry are met.

REFERENCES [l ] Rossini, F. D.. "Hydrocarbons in Petroleum," Journal of Chemical Education, Vol. 37, 1960, pp. 554-561. [2 ] Mair, B. J., "Annual Report for the Year Ending, June 30, 1967," American Petroleum Institute Research Project 6" Pittsburgh, PA, Carnegie Institute of Technology, 1967. [3 ] Rail, H.T., Thompson, C.J., Coleman, H.J., and Hopkins, R. L., "Sulfur Compounds in Oil," Bulletin 659, U.S. Department of the Interior, Bureau of Mines, 1972.

40

MANUAL ON HYDROCARBON

ANALYSIS

[4 ] Csoklich, Ch., Ebner, B., and Schenz, R., "Modern Crude Oil Practices-Austria's OEMV," The Oil and Gas Journal, March 21, 1983, pp. 86-90. [5 ] O'Donnell, R. J., "Modern Crude Oil Practices--Standard Oil of California Companies," The Oil and Gas Journal, pp. 90-93. [6 ] McNelis, F. B., "Modern Crude Oil Practices--Exxon Organizations," The Oil and Gas Journal, pp. 94-97. [7 ] Wampler, R. J. and Kirk, E. L., "Modern Crude Oil Practices-Gulf Companies," The Oil and Gas Journal, pp. 98-104. [8 ] Nelson, G.V., Schierberg, G. R., and Sequeira, A., "Modern Crude Oil Practices--The Texaco System," The Oil and Gas Journal, pp. 108, 112, 116, 118-120. [9 ] McCleskey, G. and Joffe, B. L., "Modern Crude Oil Practices-Phillips Petroleum Co.," The Oil and Gas Journal, pp. 124, 126-127. [10] Aalund, L. R., "Guide to Export Crudes for the '80s--1 to 13," The Oil and Gas Journal, April 11, May 2, 23, June 6, 20, July 4, 25, Aug. 22, Sept. 5, Oct. 24, Nov. 7, 21, Dec. 12, 19, 1983. [11 ] O'Donnell, J., "Crude Oils," Criteria for Quality of Petroleum Products, J. P. Allison, Ed., John Wiley, New York, 1973, pp. 10-21. [12 ] Smith, N. A. C., Smith, H. M., Blade, O. C., and Garton, E. L., "The Bureau of Mines Routine Method for the Analysis of Crude Petroleum 1. The Analytical Method," Bulletin 490, U.S. Department of the Interior, Bureau of Mines, 1951. [13 ] Hydrogen Sulfide and Mercaptan Sulfur in Liquid Hydrocarbons by Potentiometric Titration, Method 163, UOP Laboratory Test Methods for Petroleum and Its Products, UOP Inc., Des Plaines, IL, 1989. [14 ] Impurities in Petroleum, Petrolite Corporation, Houston, 1958. [15 ] Watson, K. M., Nelson, E. F., and Murphy, G. B., "Characterization of Petroleum Fractions," Industrial and Engineering Chemistry, Vol. 27, 1935, pp. 1460-1464. [16 ] Calculation of UOP Characterization Factor and Estimation of Molecular Weight of Petroleum Oils, Method 375, UOP Laboratory Test Methods for Petroleum and Its Products, UOP Inc., Des Plaines, IL, 1986.

[17] Nelson, W. L., "Which Base of Crude Oil is Best?" The Oil and Gas Journal, Jan. 8, 1979, pp. 112-113. [18 ] Valkovi6, V., Trace Elements in Petroleum, The Petroleum Publishing Co., Tulsa, OK, 1978. [19 ] Yen, T. F., Ed., The Role of Trace Metals in Petroleum, Ann Arbor Science Publishers, Inc., Ann Arbor, MI, 1975. [20 ] Jones, M. C. K. and Hardy, R. L., "Petroleum Ash Components and Their Effect on Refractories," Industrial and Engineering Chemistry, Vol. 44, 1952, pp. 2615-2619. [21 ] Woodle, R. A. and Chandler, W. B., Jr., "Mechanisms of Occurrence of Metals in Petroleum Distillates," Industrial and Engineering Chemistry, Vol. 44, 1952, pp. 2591-2596. [22 ] Childs, W. V. and Vickery, E. H., "The Phillips Small Sample Octane Number Methods, Automation of a Knock-Test Engine," Symposium on Laboratory and Pilot Plant Automation, Washington, DC, August 28-September 2, 1983, American Chemical Society, Washington, DC, 1983, pp. 979-990. [23 ] Richter, F.P., Caesar, P.D., Meisel, S.L., and Offenhauer, R. D., "Distribution of Nitrogen in Petroleum According to Basicity," Industrial and Engineering Chemistry, Vol. 44, 1952, pp. 2601-2605. [24] Asphaltene Precipitation with Normal Heptane, IP 143/84, Standard Methods for Analysis and Testing of Petroleum and Related Products, Vol. 1, Institute of Petroleum, London, 1988. [25 ] Dyroff, George V., Ed., Manual on Significance of Tests for Petroleum Products, 6th ed., American Society for Testing and Materials, West Conshohocken, PA, 1993. [26 ] Aalund, L. R., "Guide to Export Crudes for the '80s-- 1," The Oil and Gas Journal, April 1, 1983, p. 71. [27 ] Villalanti, D. C., Janson, D., and Colle, P., "Hydrocarbon Characterization by High Temperature Simulated Distillation," Session 4, AIChE Spring Meeting, Houston, TX, March 19-23, 1995. [28 ] Application Note 9701, "Characterization of Vacuum Gas Oils by the AC Heavy Distillates Analyzer," AC--Analytical Controls Inc., Bensalem, PA.

7

Analysis of Aromatic Hydrocarbons by Charles H. Pfeiffer INTRODUCTION

Eventually all of the light aromatics obtainable from the coking operation were being used and shortages occurred. The world needed another source, and that source was petroleum. Even as early as the late 1920s, crude oil was evaluated as a source of light aromatics. Not until the late 1940s, however, did the development of catalytic reforming and liquidliquid extraction provide large quantities of aromatic hydrocarbons for use by the chemical industry and as a blending ingredient in high-octane gasoline.

THE HISTORYOF INDUSTRIALanalyses of aromatic hydrocarbons began in the 1920s when the production of benzene from coke by-products became commercially viable. By the 1930s, the rapid growth in demand for benzene as well as the commercial production of heavier aromatics led to the formulation of a considerable number of empirical analytical procedures. At this time, ASTM Committee D16 on Aromatic Hydrocarbons was formed. In the more than 50 years that this group has been active, the changes in analytical techniques have progressed hand-in-hand with the advancements in process technology and the expansion in the demand for high-purity aromatic products. As coal was heated in the absence of oxygen to produce coke, the lighter chemicals were vaporized and separated from the coal. Cooling the vapors condensed a highly aromatic liquid. Fractional distillation was used to separate the hydrocarbons into narrow-boiling fractions representing single aromatics, such as benzene, or groups of aromatics, such as xylenes. The contaminants were largely sulfur-, oxygen-, and nitrogen-containing hydrocarbons. Estimates of the purity of these products were determined in laboratories using procedures such as ASTM Test Methods D850, Distillation of Industrial Aromatic Hydrocarbons and Related Materials, 1 and D852, Solidification Point of Benzene. t Contaminants in the products caused corrosion and product degradation in the downstream units. The following ASTM Test Methods were developed to address these problems: ASTM Test Methods D853, Hydrogen Sulfide and Sulfur Dioxide Content (Qualitative) of Industrial Aromatic Hydrocarbons/ D848, Acid Wash Color of Industrial Aromatic H y d r o c a r b o n s / a n d D849, Copper Strip Corrosion of Industrial Aromatic Hydrocarbons. ~ As processes improved, aromatic hydrocarbons became available at substantially higher purities. The higher product purities opened up new industrial applications and required new standards. To make these materials easier to buy, sell, and trade, ASTM Test Methods D1015, Freezing Points of High-Purity Hydrocarbons,2 D 1016, Purity of Hydrocarbons from Freezing Points, 2 and D 1078, Distillation Range of Volatile Organic Liquids/ were published. Later, methods that gave more specific compositional information would supplant these empirical tests.

CURRENT PRACTICES Cyclohexane, made from benzene, is a chemical intermediate in the production of nylon. Polyester is made from p-xylene, which is extracted from mixed xylenes. Synthetic rubber is made from styrene, which is made from ethylbenzene. Resins are made from phenol, which is made from cumene. Each of these feedstocks and intermediates requires a specific purity level as well as limits on specific impurities and groups of impurities. ASTM test methods were developed and revised in ASTM Committee D16 as each of these needs were identified and as requirements for each of the materials changed. Gas chromatography (GC) has become a primary technique for determining hydrocarbon impurities in individual aromatic hydrocarbons and the composition of mixed aromatic hydrocarbons. Although a measure of purity by GC is often sufficient, GC is not capable of measuring absolute purity; not all possible impurities will pass through the GC column, and not all those that do will be measured by the detector. Absolute purity is best measured by distillation range or freeze or solidification points. Despite this caveat, GC is a standard, widely used technique and is the basis of many current ASTM Committee D16 test methods for aromatic hydrocarbons. Most of these methods, listed below, were written with, or converted to, fused silica capillary columns. D2306 D2360 D3054 D3760

1Appears in this publication.

D3797

2Annual Book of ASTM Standards, Vol. 05.01.

41

Cs Aromatic Hydrocarbon Analysis by Gas Chromatography ~ Trace Impurities in Monocyclic Aromatic Hydrocarbons by Gas Chromatography 1 Purity and Benzene Content of Cyclohexane by Gas Chromatography I Analysis of Isopropylbenzene (Cumene) by Gas Chromatography ~ Analysis of o-Xylene by Gas Chromatography ~

42

MANUAL ON HYDROCARBON ANALYSIS

D3798 D4492 D4534 D4735 D5060 D5135 D5713 D5917

D6144

Analysis of p-Xylene by Gas Chromatography ~ Analysis of Benzene by Gas Chromatography 1 Benzene Content of Cyclic Products by Gas Chromatography 1 Determination of Trace Thiophene in Refined Benzene by Gas Chromatography ~ Determining Impurities in High-Purity Ethylbenzene by Gas Chromatography ~ Analysis of Styrene by Capillary Gas Chromatography 1 Analysis of High Purity Benzene for Cyclohexane Feedstock by Capillary Gas Chromatography 1 Trace Impurities in Monocyclic Aromatic Hydrocarbons by Gas Chromatography and External Calibration 1 Analysis of AMS (a-Methylstyrene) by Gas Chromatography I

When classes of hydrocarbons, such as olefins, need to be measured, techniques such as bromine index are used. ASTM Test Method D1492, Bromine Index of Aromatic Hydrocarbons by Coulometric Titration/ continues as a useful method, but D1491, Bromine Index of Aromatic Hydrocarbons by Potentiometric Titration, 3 was withdrawn in 1985 because of health concerns regarding its use of carbon tetrachloride as a solvent. It was eventually replaced by D5776, Bromine Index of Aromatic Hydrocarbons by Electrometric Titration,~ which is based on D2710, Bromine Index of Petroleum Hydrocarbons by Electrometric Titration, ~but uses the less toxic 1-methyl-2-pyrrolidinone as a solvent. Impurities other than hydrocarbons are of concern in the petroleum industry. For example, many catalytic processes are sensitive to sulfur contaminants. Consequently, ASTM committees responded by developing a series of state-of-theart methods to determine trace concentrations of sulfur-containing compounds. These methods included ASTM Test Methods D 1685, Traces of Thiophene in Benzene by Spectrophotometry/D3961, Trace Quantities of Sulfur in Liquid Aromatic Hydrocarbons by Oxidative Microcoulometry, D4045, Sulfur in Petroleum Products by Hydrogenolysis and Rateometric Colorimetry, 1 and D4735, Trace Thiophene in Refined Benzene by Gas ChromatographyJ Chloride-containing impurities are determined by ASTM Test Methods D5194, Trace Chloride in Liquid Aromatic Hydrocarbons/ and D5808, Determining Organic Chloride in Aromatic Hydrocarbons and Related Chemicals by Microcoulometry. l Nitrogen-containing impurities are determined by ASTM Test Method D6069, Trace Nitrogen in Aromatic Hydrocarbons by Oxidative Combustion and Reduced Pressure Chemiluminescence DetectionJ Many of these test methods have sensitivity to 1 mg/kg, reflecting the needs of industry to determine very low levels of these contaminants. In addition to those tests previously mentioned, a number of other ASTM Test Methods are regularly used for the analysis of aromatics and are listed below: D847

Acidity of Benzene, Toluene, Xylenes, Solvent Naphthas, and Similar Industrial Aromatic Hydrocarbons 4

3Discontinued; see 1985 Annual Book of ASTM Standards, Vol. 06.03.

D1493 D1555 D1686

D2119 D2121 D2340 D2935 D3160 D3505 D3799 D4590

Solidification Point of Industrial Organic Chemicals 4 Calculation of Volume and Weight of Industrial Aromatic Hydrocarbons4 Color of Solid Aromatic Hydrocarbons and Related Materials in the Molten State (Platinum-Cobalt Scale) 4 Aldehydes in Styrene Monomer 4 Polymer Content of Styrene Monomer 4 Peroxides in Styrene Monomer 4 Apparent Density of Industrial Aromatic Hydrocarbons 4 Phenol Content of Cumene (Isopropylbenzene) or AMS (~-Methylstyrene) 4 Density or Relative Density of Pure Liquid Chemicals 4 Purity of Styrene by Freezing Point Method 4 Colorimetric Determination of p-tert-Butylcatechol in Styrene Monomer or AMS (a-Methylstyrene) by Spectrophotometry4

FUTURE TRENDS Timeliness of analyses and the amount of labor required to perform them continue to grow in importance. Although many laboratories have limits on staffing, they may still be able to make a one-time capital purchase of equipment to make the available staff more productive. Instrumental and automated methods are replacing chemical and physical methods in the laboratories, and ASTM is supporting this trend by writing test methods using contemporary technology and by listing these test methods in ASTM specifications. The ability of ASTM Committee D16 to write these methods in a timely manner has been made possible, in part, by increased vendor activity, a trend that is expected to continue. For relative density, most labs now use ASTM Test Method D4052, Density and Relative Density of Liquids by Digital Density Meter. 1 Distillation methods have been or are being rewritten to include automated distillation apparatus. For trace sulfur, D4045 has become the industry standard. Recently, this method has been optimized for aromatics analysis as ASTM Test Method D6212, Total Sulfur in Aromatic Compounds by Hydrogenolysis and Rateometric ColorimetryJ Development in D16.0E on a proposed method, "Total Sulfur in Aromatic Compounds by Oxyhydropyrolysis and Difference Photometry," is continuing, utilizing new equipment. Methods for trace sulfur and trace nitrogen by electrochemical detection have also been proposed. The classic platinum-cobalt color method, ASTM Test Method D1209, Color of Clear Liquids (Platinum-Cobalt Scale)/which requires subjective visual color comparison, is slowly being replaced by methods such as ASTM Test Method D5386, Color of Liquids Using Tristimulus Colorimetry.l This new standard is currently limited to a maximum color of 30 because, for higher color values, the vendors' algorithms to convert tristimulus values to Pt-Co color produce different results. Currently, three major instrument manufacturers are 4Annual Book of ASTM Standards, Vo]. 06.04.

CHAPTER 7 - - A N A L Y S I S OF AROMATIC HYDROCARBONS working together on a common algorithm, which may be published as an appendix to the standard. The labor requirements of GC methods are also being addressed. Traditionally, trace analyses by GC have been quantitated using an internal standard for calibration. These test methods require careful weighing procedures for each sample. Now, with the routine use of autosamplers to provide repeatable injections, an external standard procedure is preferred as a means of saving analyst time. Trace impurities by GC, ASTM Test Method D5917, was written as an equivalent to the internal standard GC method D2360. Because of continuing concerns over labor requirements, ASTM Committee D 16 is currently trying to eliminate redundant tests in Committee DI6 Specifications. For example, if a specification for high-purity benzene includes distillation range, purity by GC, and solidification point, a density or

43

relative density test is not justified. Similarly, current commercial high-purity aromatic hydrocarbons always pass acidity, copper corrosion, hydrogen sulfide, and sulfur dioxide tests, so the continuing need for these tests on a routine basis is being questioned. More stringent product requirements, advanced catalytic processing techniques, improved feedstock purification for specific downstream processes, and health and environmental requirements are driving the limits of impurities into the less than parts-per-million range. Efforts to provide quantitative analyses at this level continue. As raw material sources, product distributions, and methodologies change, efforts to publish methods based on current technology will continue to go hand-in-hand with these industrial technological changes.

Part 2--ASTM Test Methods The test m e t h o d s herein are a r r a n g e d in a l p h a n u m e r i c sequence. The page n u m b e r s a p p l y only to this m a n u a l a n d not to the s t a n d a r d d o c u m e n t s as they a p p e a r in the a n n u a l ASTM Book of Standards. See Table 2 in the front of this m a n u a l for a list of test m e t h o d s b y subject.

45

l]~ Designation:

D

5 - 95

Standard Test Method for Penetration of Bituminous Materials I This standard is issued under the fixed de~gnation D 5; the number immediately following the de~gnation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (E) indicates an editorial change since the last revision or reapproval.

This test method has been approved for use by agencies of the Department of Defense. Consult the DoD Index of Specifications and Standards for the specific year of issue which has been adopted by the Department of Defense.

1. Scope 1. I This test method covers determination of the penetration of semi-solid and solid bituminous materials. 1.2 The needles, containers and other conditions described in this test method provide for the determinations of penetrations up to 500. 1.3 The values stated in SI units are to be considered standard. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

5. Significance and Use 5.1 The penetration test is used as a measure of consistency. Higher values of penetration indicate softer consistency. 6. Apparatus 6.1 Penetration ApparatusDAny apparatus that permits the needle holder (spindle) to move vertically without measurable friction and is capable of indicating the depth of penetration to the nearest 0.1 ram, will be acceptable. The weight of the spindle shall be 47.5 + 0.05 g. The total weight of the needle and spindle assembly shall be 50.0 + 0.05 g. Weights of 50 + 0.05 g and 100 ± 0.05 g shall also be provided for total loads of I00 g and 200 g, as required for some conditions of the test.The surface on which the sample container rests shall be flatand the axis of the plunger shall be at approximately 90" to this surface. The spindle shall be easily detached for checking its weight. 6.2 Penetration Needle: 6.2.1 The needle (see Fig. 1) shall be made from fully hardened and tempered stainless steel, Grade 440-C or equal, HRC 54 to 60. The standard needle shall be approximately 50 mm (2 in.) in length, the long needle approximately 60 mm (24 in.). 6 The diameter of all needles shall be 1.00 to 1.02 mm (0.0394 to 0.0402 in.). It shall be symmetrically tapered at one end by grinding to a cone having an angle between 8.7 and 9.7" over the entire cone length. The cone should be coaxial with the straight body of the needle. The total axial variation of the intersection between the conical and straight surfaces shall not be in excess of 0.2 mm (0.008 in.). The truncated tip of the cone shall be within the diameter limits of 0.14 and 0.16 mm (0.0055 and 0.0063 in.) and square to the needle axis within 2". The entire edge of the truncated surface at the tip shall be sharp and free of burrs. When the surface texture is measured in accordance with American National Standard B46.1 the surface roughness height of the tapered cone shall be 0.2 to 0.3 ~tm (8 to 12 ~tin.) arithmetic average. The needle shall be mounted in a non-corroding metal ferrule. The ferrule shall be 3.2 ± 0.05 mm (0.12 ± 0.003 in.) in diameter and 38 ± 1 mm (1.50 ± 0.04 in.) in length. The exposed length of the standard nee~e shall be within the limits of 40 to 45 mm (1.57 to 1.77 in.), and the exposed length of the long needle shall be 50 to 55 mm (1.97 to 2.19 in.). The needle shall be rigidly mounted in the ferrule. The run-out (total-indicator reading) of the needle tip and any portion of the needle relative to the

2. Referenced Documents 2.1 A S T M Standards: C 670 Practice for Preparing Precision and Bias Statements for Test Methods for Construction Materials2 D 36 Test Method for Softening Point of Bitumen (Ringand-Ball Apparatus) 3 E 1 Specification for ASTM Thermometers4 E 77 Test Method for Inspection and Verification of Liquid-in-Glass Thermometers4 2.2 ANSI Standard? B 46.1 Surface Texture 3. Terminology 3.1 Definition: 3.1.1 penetration, n--consistency of a bituminous material expressed as the distance in tenths of a millimeter that a standard needle vertically penetrates a sample of the material under known conditions of loading, time, and temperature.

4. Summary of Test Method 4.1 The sample is melted and cooled under controlled conditions. The penetration is measured with a penetrometer by means of which a standard needle is applied to the sample under specificconditions. i This test method is under the jurisdiction of ASTM Committee D-4 on Road and Paving Materials and is the direct responsibility of Subcommittee 1304.44 on

Rheolngical Tests. Current edition approved Sept. 10, 1995. Published February 1996. Originally published as D 5 - 59 T. Last previous edition D 5 - 94. 2 Annual Book of ASTM Standards, Vol 04.02. 3 Annual Book of ASTM Standards, Vol 04.04. 4 Annual Book of ASTM Standards, Vol 14.03. 5 Available from American National Standards Institute, I I W. 42nd St., 13th Floor, New York, NY 10036.

e Long needles are available from Stanhope-Seta, Park Close, Englefleld Green, Eglmm, Surrey, U.K. TW20 OXD.

47

~ DS ,100 /o /02mm

e ......... FiG. 1

6.7 Thermometers--Calibrated liquid-in-glass thermometers of suitable range with subdivisions and maximum scale error of 0. I*C (0.2*F) or any other thermometric device of equal accuracy, precision and sensitivity shall be used. Thermometers shall conform to the requirements of Specification E 1. 6.7.1 Suitable thermometers commonly used are:

0./4/o 0./6 m m d~°4-O' to 9°dO '.- .

"'r approx. lL _1 as required----L~-J~--"-'-"-~--'~=~----"

Needle for Penetration Test

ferrule axis shall not exceed 1 mm (0.04 in.). The weight of the ferrule needle assembly shall be 2.50 _.+ 0.05 g. (A drill hole at the end of the ferrule or a fiat on the side is permissible to control the weight.) Individual identification markings shall be placed on the ferrule of each needle; the same markings shall not be repeated by a manufacturer within a 3-year period. 6.2.2 Needles used in testing materials for conformance to specifications shall be shown to have met the requirements of 6.2.1 when tested by a qualified agency. 6.3 Sample ContainerV--A metal or glass cylindrical, fiat-bottom container of essentially the following dimensions shall be used:

Range

17C or 17F

19 to 27*(2 (66 to 80°F)

63C or 63F 64(2 or 64F

- 8 to +32"(2 (18 to 89"F) 25 to 55"C (77 to 131"F')

6.7.2 The thermometer used for the water bath shall periodically be calibrated in accordance with Test Method E77.

7. Preparation of Test Specimen 7.1 Heat the sample with care, stirring when possible to prevent local overheating, until it has become sufficiently fluid to pour. In no ease should the temperature be raised to more than 60"C above the expected softening point for tar pitch in accordance with Test Method D 36, or to more than 90"C above it for petroleum asphalt (bitumen). Do not heat samples for more than 30 min. Avoid incorporating bubbles into the sample. 7.2 Pour the sample into the sample container to a depth such that, when cooled to the temperature of test, the depth of the sample is at least 10 mm greater than the depth to which the needle is expected to penetrate. Pour two separate portions for each variation in test conditions. 7.3 Loosely cover each container as a protection against dust (a convenient way of doing this is by covering with a lipped beaker) and allow to cool in air at a temperature between 15 and 30"C for 1 to 1.5 h for the small container and 1.5 to 2 h for the taller. Then place the two samples together with the transfer dish, if used, in the water bath maintained at the prescribed temperature of test. Allow the smaller container to remain for 1 to 1.5 h and the taller (6 oz) container to remain for 1.5 to 2 h.

For penetrations below 200:

Diameter, mm Internal depth, mm For penetrations between 200 and 350: Diameter, mm Internal depth, mm

ASTM Number

55 35 55 70

6.4 Water B a t h - - A bath having a capacity of at least 10 L and capable of maintaining a temperature of 25 + 0. I*C or any other temperature of test within 0. I*C. The bath shall have a perforated shelf supported in a position not less than 50 mm from the bottom and not less than 100 mm below the liquid level in the bath. If penetration tests are to be made in the bath itself, an additional shelf strong enough to support the penetrometer shall be provided. Brine may be used in the bath for determinations at low temperatures. NoTE l - - T h e use o f distilled water is recommended for the bath. Take care to avoid contamination o f the bath water by surface active agents, release agents, or other chemicals; as their presence may affect the penetration values obtained.

8. Test Conditions 8.1 Where the conditions of test are not specifically mentioned, the temperature, load, and time are understood to be 25"C (77"F), 100 g, and 5 s, respectively. Other conditions may be used for special testing, such as the following:

6.5 Transfer D i s h - - W h e n used, the transfer dish shall have a capacity of at least 350 mL and of sufficient depth of water to cover the large sample container. It shall be provided with some means for obtaining a firm bearing and preventing rocking of the container. A three-legged stand with three-point contact for the sample container is a convenient way of ensuring this. 6.6 Timing Device--For hand-operated-penetrometers any convenient timing device such as an electric timer, a stop watch, or other spring activated device may be used provided it is graduated in 0.1 s or less and is accurate to within +0.1 s for a 60-s interval. An audible seconds counter adjusted to provide 1 beat each 0.5 s may also be used. The time for a 1 l-count interval must be 5 + 0.1 s. Any automatic timing device attached to a penetrometer must be accurately calibrated to provide the desired test interval within +0.1 s.

Temperature, "C ('F) 0 (32) 4 (39.2) 45 (113) 46.1 (I 15)

Load, g

Time, s

200 200 50 50

60 60 5 5

In such cases the specific conditions of test shall be reported. 9. Procedure 9. I Examine the needle holder and guide to establish the absence of water and other extraneous materials. If the penetration is expected to exceed 350 use a long needle, otherwise use a short needle. Clean a penetration needle with toluene or other suitable solvent, dry with a clean cloth, and insert the needle into the penetrometer. Unless otherwise specified place the 50-g weight above the needle, making the total weight 100 + 0.1 g.

vSample Containers are available from Ellisco Inc., 6301 Eastern Ave., Baltimore MD, 21224 and Freund Can Co., 155 West 84th St., Chicago IL, 60620-1298.

48

(I~Ti~ D S TABLE 1

9.2 If tests are to be made with the penetrometer in the bath, place the sample container directly on the submerged stand of the penetrometer (Note 2). Keep the sample container completely covered with water in the bath. If the tests are to be made with the penetrometer outside the bath, place the sample container in the transfer dish, cover the container completely with water from the constant temperature bath and place the transfer dish on the stand of the penetrometer. NOTE 2--For referee tests, penetrationsat temperatures other than 25°C (77"F) should be made without removing the sample from the bath.

Matedal

Single-operator predsion: Asphalts at 77"F (25*(3) below 50 Asphalts at 77"F (25"C) 50 penetration lull above, percent of thelr mean Tar pltct~s at 770F (250C)A percent of thelr mean Asphalts at 770F (250C) below 50 penetration, units Asphalts at 770F (2SoC) 50 penetration and above, percent of thelr rnean Tar pitches at 770F (25*C),A units

49

149

249

500

2

4

12

20

1

1.1

3

5.2

15

1.4 2.8 1.4

precision at other temperatures is being determined. 11.1.1 Single Operator PrecisionmThe single operator coefficient of variation has been found to be 1.4 % for penetrations above 60, and the single operator standard deviation has been found to be 0.35 % for penetrations below 50. Therefore, the results of two properly conducted tests by the same operator on the same material of any penetration, using the same equipment, should not differ from each other by more than 4 % of their mean, or I unit, whichever is larger. 11.1.2 Multilaboratory Precision--The multilaboratory coefficient of variation has been found to be 3.8 % for penetrations above 60, and the multilaboratory standard deviation has been found to be 1.4 for penetrations below 50. Therefore, the results of two properly conducted tests on the same material of any penetration, in two different laboratories, should not differ from each other by more than 11% of their mean, or 4 units, whichever is larger.

10. Report 10.1 Report to nearest whole unit the average of three penetrations whose values do not differ by more than the following: Penetration Maximum difference between highest and lowest penetration

0.35

,~ ~ N of predsk~ for tar pltches are _~___,~'Jon results from 2 pitches with penetraUonof 7 and 24. Estimates may not be appUcal~ to apprec/ablyharder or softer matsdm.

9.4 Make at least three determinations at points on the surface of the sample not less than 10 mm from the side of the container and not less than 10 mm apart. If the transfer dish is used, return the sample and transfer dish to the constant temperature bath between determinations. Use a clean needle for each determination. If the penetration is greater than 200, use at least three needles leaving them in the sample until the three determinations have been completed.

250to

(d2s) or (d2s ~)

MulBaboratoryprec~¢~:

NOTE 3--The positioning of the needle can be materially aided by

150to

Acceptable Range of Two Test Results

penetration,units

using an illuminatedpoly-methylmethacrylatetube.

50to

Standard Deviation or Coefficient of Variation (Is) or

(is x)

9.3 Position the needle by slowly lowering it until its tip just makes contact with the surface of the sample. This is accomplished by bringing the actual needle tip into contact with its image reflected on the surface of the sample from a properly placed source of fight (Note 3). Either note the reading of the penetrometer dial or bring the pointer to zero. Quickly release the needle holder for the specified period of time and adjust the instrument to measure the distance penetrated in tenths of a millimetre. If the container moves, ignore the result.

0to

Precision Cr~llrli

NOTE 4---These values represent, respectively, the dls (or dls %) and

d2s (or d2s %) limits as d__~cri_ "bed in PracticeC 670. 11.1.3 Bias--This test method has no bias because the values determined arc defined only in terms of the test method.

11. Precision and Bias 11.1 Use the following criteria for judging the acceptability of penetration results for asphalt at 25"C. The

12. Keywords 12.1 asphalt; bitumen; penetration

The American Society for Testing and Materials takes no position respecting the vahdity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the vahdity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting ol the responsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 100 Barr Herbor Drive, West Conshohocken, PA 19428.

49

(~~ll~ Designation: D 36 - 95 Standard Test Method for Softening Point of Bitumen (Ring-and-Ball Apparatus) 1 This standard is issued under the fixed designation D 36; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (~) indicates an editorial change since the last revision or reapproval.

bitumens, as one element in establishing the uniformity of shipments or sources of supply, and is indicative of the tendency of the material to flow at elevated temperatures encountered in service.

1. Scope 1.1 This test method covers the determination of the softening point of bitumen in the range from 30 to 157"C (86 to 315"F) using the ring-and-ball apparatus immersed in distilled water (30 to 80"C), USP glycerin (above 80 to 157"C), or ethylene glycol (30 to 110*C). 1.2 The values stated in SI units are to be regarded as the standard. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

5. Apparatus 5.1 Rings--Two square-shouldered brass rings conforming to the dimensions shown in Fig. l(a). 5.2 Pouring Plate--A fiat, smooth, brass plate approximately 50 by 75 mm (2 by 3 in.). 5.3 Balls--Two steel balls, 9.5 mm (3/8 in.) in diameter, each having a mass of 3.50 _ 0.05 g. 5.4 Ball-Centering Guides--Two brass guides for centering the steel balls, one for each ring, conforming to the general shape and dimensions shown in Fig. 1 (b). 5.5 Bath--A glass vessel, capable of being heated, not less than 85 mm in inside diameter and not less than 120 mm in depth from the bottom of the flare.

2. Referenced Documents

2.1 ASTM Standards." C 670 Practice for Preparing Precision and Bias Statements for Test Methods for Construction Materials 2 D 92 Test Method for Flash and Fire Points by Cleveland Open Cup 3 D 140 Practice for Sampling Bituminous Materials4 D 3461 Test Method for Softening Point of Asphalt and Pitch (Mettler Cup-and-Ball Method) s E 1 Specification for ASTM Thermometers 6

NOTe I - - A n 800-mL, low-form Griffin beaker of heat-resistant glass meets this requirement.

5.6 Ring Holder and Assembly--A brass holder designed to support the two rings in a horizontal position, conforming to the shape and dimensions shown in Fig. 1 (c), supported in the assembly illustrated in Fig, 1 (d). The bottom of the shouldered rings in the ring holder shall be 25 mm (I.0 in.) above the upper surface of the bottom plate, and the lower surface of the bottom plate shall be 16 + 3 mm (% _+ I/s in.) from the bottom of the bath. 5.7 Thermometers: 5.7.1 An ASTM Low Softening Point Thermometer, having a range from - 2 to + 80"C or 30 to 180*F, and conforming to the requirements for Thermometer 15C or 15F as prescribed in Specification E 1. 5.7.2 An ASTM High Softening Point Thermometer, having a range from 30 to 200"C or 85 to 392"F, and conforming to the requirements for Thermometer 16C or 16F as prescribed in Specification E 1. 5.7.3 The appropriate thermometer shall be suspended in the assembly as shown in Fig. I (d) so that the bottom of the bulb is level with the bottom of the rings and within 13 mm (0.5 in.) of the rings, but not touching them or the ring holder. Substitution of other thermometers shall not be permittted.

3. Summary of Test Method 3.1 Two horizontal disks of bitumen, cast in shouldered brass rings, are heated at a controlled rate in a liquid bath while each supports a steel ball. The softening point is reported as the mean of the temperatures at which the two disks soften enough to allow each ball, enveloped in bitumen, to fall a distance of 25 mm (1.0 in.). 4. Significance and Use 4.1 Bitumens are viscoelastic materials without sharply defined melting points; they gradually become softer and less viscous as the temperature rises. For this reason, softening points must be determined by an arbitrary and closely defined method if results are to be reproducible. 4.2 The softening point is useful in the classification of This test method is under the jurisdhction of ASTM Committee D-8 on Roofing, Waterproofing, and Bituminous Materials and is the direct responsibdity of Subcommittee I:)08.03 on Surfacing and Bituminous Materials for Membrane Waterproofing and Builtup Roofing. Current edition approved Oct. 10, 1995. Published December 1995. Originally published as D 36 - 62T. Last previous edition D 36 - 86 (1993) ~j. 2 Annual Book ¢fASTM Standards, Vol 04.02. 3 Annual Book ¢fASTM Standards, Vol 05.01. 4 Annual Book of ASTM Standards, Vol 04.03. 5 Annual Book of ASTM Standards, Vol 04.04. 6 Annual Book of ASTM Standards, Vol 14.03.

6. Reagents and Materials 6.1 Bath Liquids: 6.1.1 Freshly Boiled Distilled Water. NOTE 2 - - T h e use o f freshly boiled distilled water is essential to avoid trapping air bubbles on the surface o f the specimen which m a y affect the

results.

50

I1~ D 36 I

Q

.. - "1 ZO~ ss

, / ~ slightly (opprox/motely O.OJ mmll /l. _.~ Iorger Ihon 9 ~ m m to o/Iowploc/n~:'~;-'~ ond centerin~ 9.5-ram steel boll.

Note: This diomefer to be

I---,.

--19.0- - ~

Th/s ring.

I

r/~

rtld

l.-- ..o--J Inside "D/ometer Full 23.0ram to slide over ring

"

vIA

'

"... -J

Note: diometer to be ~" full lg.0mm t o ~ r m # I n s e r t i o n ,, s of

-4 s.61,,

]0o

_L

(o) Shouldered Ring

¢~

iI i

q.

P,'-- 15.9- ~1

I.

, ,

i~qo. ~ ~,

.-Rounded lrillef • -z3.o

"%~

rid

(b) Boll Centering Guide

1/ '

rr a

(c) Ring Holder

(d) Two-Ring Assembly NOTE~AIIdimensionsare in millimetres. FIG. 1 Shouldered Ring, Bali-Centering Guide, Ring Holder, and Assembly of Apparatus Showing Two Rings 6.1.2

USPGlycerin,or

in other tests such as those for penetration and flash point.

NOTE 3--CAUTION:--Glycerin has a flash point of 160"C (320"F) in accordance with Test Method D 92.

7. Sampling

EthyleneGlycol,

7.1 Sample the material in accordance with Practice D 140.

6.1.3 with a boiling point between 195 and 197"C (383 and 387"F). NOTE 4--CAUTION:--Ethylene glycol is toxic when taken internally or inhaled as a vapor. Avoid prolonged or repeated skin contact and inhalation of vapors. Its flash point is 115°C (239°F) in accordance with Test Method D 92. When using this bath liquid, conduct the test in a vented laboratory hood with adequate exhaust fan capacity to ensure removal of toxic vapors.

8. Test

Specimens

8.1 Do not start unless it is planned to complete preparation and testing o f all asphalt specimens within 6 h and all coal-tar pitch specimens within 41/2 h. Heat the bitumen sample with care, stirring frequently to prevent local overheating, until it has become sufficiently fluid to pour (Note 6). Stir carefully to avoid incorporation of air bubbles in the sample.

ReleaseAgenls."

6.2 6.2.1 To prevent adhesion of bitumen to the pouring plate when casting disks, the surface of the brass pouring plate may be thinly coated just before use with silicone oil or grease (Note 5), a mixture o f glycerin and dextrin, talc, or china clay.

NOTE 6--An electric hot plate having a minimum power to unitsurface-area ratio of 37 k W / m 2 has been found satisfactory for this purpose.

NOTE 5--CAUTION:--Isolate silicones from other bituminous testing equipment and samples to avoid contamination, and wear disposable rubber gloves whenever handling silicones or apparatus coated with them. Silicone contamination can produce erroneous results

8. I. l Take no more than 2 h to heat an asphalt sample to its pouring temperature; in no case shall this be more than 110*C (200*F) above the expected softening point o f the asphalt. 51

~ 8.1.2 Take no more than 30 min to heat a coal-tar pitch sample to its pouring temperature; in no case shall this be more than 55"C (100*F) above the expected softening point of the coal-tar-pitch. 8.1.3 If the test must be repeated later, do not reheat this sample; use a fresh sample in a clean container to prepare new test specimens. 8.2 Heat the two brass rings (but not the pouring plate) to the approximate pouring temperature, and place them on the pouring plate treated with one of the release agents. 8.3 Pour a slight excess of the heated bitumen into each ring, and then allow the specimens to cool in ambient air for at least 30 min. For materials that are soft at room temperature, cool the specimens for at least 30 min at an air temperature at least 10*C (18*F) below the expected softening point. From the time the specimen disks are poured, no more than 240 min shall elapse before completion of the test. 8.4 When the specimens have cooled, cut away the excess bitumen cleanly with a slightly heated knife or spatula, so that each disk is flush and level with the top of its ring.

D 36 (_ 1.0*F). Reject any test in which the rate of temperature rise does not fall within these limits. NOTE 7--Rigid adherence to the prescribed heating rate is essential to reproducibility of results. Either a gas burner or electric heater may be used, but the latter must be of the low-lag, variable output type to maintain the prescribed rate of heating. 9.6 Record for each ring and ball the temperature indicated by the thermometer at the instant the bitumen surrounding the ball touches the bottom plate. Make no correction for the emergent stem of the thermometer. If the difference between the two temperatures exceeds I*C (2*F), repeat the test. 10. Calculation 10.1 For a given bitumen specimen, the softening point determined in a water bath will be lower than that determined in a glycerin bath. Since the softening point determination is necessarily arbitrary, this difference matters only for softening points slightly above 80"C (176*F). 10.2 The change from water to glycerin for softening points above 80"C creates a discontinuity. With rounding, the lowest possible asphalt softening point reported in glycerin is 84.5"C (184"F), and the lowest possible coal-tar pitch softening point reported in glycerin is 82.0"C (180*F). Softening points in glycerin lower than these translate to softening points in water of 80"C (176"F) or less, and shall be so reported. 10.2. l The correction for asphalt is -4.2"C (-7.6"F), and for coal-tar pitch is -1.7*C (-3.0*F). For referee purposes, repeat the test in a water bath. 10.2.2 Under any circumstances, if the mean of the two temperatures determined in glycerin is 80.0"C (176.0*F) or lower for asphalt, or 77.5"C (171.5*F) or lower for coal-tar pitch, repeat the test in a water bath. 10.3 To convert softening points slightly above 80"C (176"F) determined in water to those determined in glycerin, the correction for asphalt is +4.2"C (+7.6"F) and for coal-tar pitch is + 1.7*C (+3.0*F). For referee purposes, repeat the test in a glycerin bath. 10.3.1 Under any circumstances, if the mean of the two temperatures determined in water is 85.0"C (185.0"F) or higher, repeat the test in a glycerin bath. 10.4 Results obtained by using an ethylene glycol bath will vary from those using water and glycerin. The following formulas shall be used to calculate the differences:

9. Procedure 9.1 Select one of the following bath liquids and thermometers appropriate for the expected softening point: 9.1.1 Freshly boiled distilled water for softening points between 30 and 80"C (86 and 176"F); use Thermometer 15C or 15F. The starting bath temperature shall be 5 +I*C (41 + 2*F). 9.1.2 U S P glycerin for softening points above 80"C (176"F) and up to 157"C (315"F); use Thermometer 16C or 16F. The starting bath temperature shall be 30 + I*C (86 ± 2*F). 9.1.3 Ethylene glycol for softening points between 30 and 110°C (86 and 230°F); use Thermometer 16C or 16F. The starting bath temperature shall be 5 ± I°C (41 ± 2*F). 9.1.4 For referee purposes, all softening points up to 80*C (176°F) shall be determined in a water bath and all softening points above 80°C (176°F) shall be determined in a glycerin bath. 9.2 Assemble the apparatus in the laboratory hood with the specimen rings, ball-centering guides, and thermometer in position, and fill the bath so that the liquid depth will be 105 ± 3 mm (4'/8,± '/s in.) with the apparatus in place. If using ethylene glycol, make sure the hood exhaust fan is turned on and operating properly to remove toxic vapors. Using forceps, place the two steel balls in the bottom of the bath so they will reach the same starting temperature as the rest of the assembly. 9.3 Place the bath in ice water, if necessary, or gently heat to establish and maintain the proper starting bath temperature for 15 min with the apparatus in place. Take care not to contaminate the bath liquid. 9.4 Again using forceps, place a ball from the bottom of the bath in each ball-centering guide. 9.5 Heat the bath from below so that the temperature indicated by the thermometer rises at a uniform rate of 5"C (9*F)/min (Note 7). Protect the bath from drafts, using shields if necessary. Do not average the rate of temperature rise over the test period. The maximum permissible variation for any l-rain period after the first 3 rain shall be ± 0.5"C

Asphalt: SP (glycerin) -- 1.026583 × SP (ethylene glycol) - 1.334968°C SP (water) = 0.974118 x SP (ethylene glycol) - 1.44459°C

Coal Tar." SP (glycerin) = 1.044795 x SP (ethylene glycol) - 5.063574°C fSP (water) = 1.061111 x SP (ethylene glycol) - 8.413488°C 11. Report 11.1 When using ASTM Thermometer 15C or 15F, report to the nearest 0.2"C or 0.5*F the mean or corrected mean of the temperatures recorded in 9.6 as the softening point. ? Editoriallycorrected. 52

o a6 same sample of bitumen from two laboratories should not differ by more than 2.0"C (3.5"17).7 12.2 With ethylene glycol, the following criteria shall be used for judging the acceptability of results: 12.2. l Single-Operator Precision--The single-operator standard deviation has been found to be 0.72"C (1.29"F). Therefore, results of two properly conducted tests by the same operator on the same sample of bitumen should not differ by more than 2.0"C (3.5"F). 7 12.2.2 Multilaboratory Precision--The multilaboratory standard deviation has been found to be 1.08*C (1.95"F). Therefore, results of two properly conducted tests on the same sample of bitumen from two laboratories should not differ by more than 3.0"C (5.5"F). 7 12.3 BiasmThe procedure in Test Method D 36 has no bias because the value of the softening point of the bitumen test is defined in terms of this test method.

11.2 When using ASTM Thermometer 16C or 16F report to the nearest 0.5"C or 1.0*F the mean or corrected mean of the temperatures recorded in 9.6 as the softening point. 11.3 Report the bath liquid used in the test. 12. Precision and Bias 12.1 With distilled water or USP glycerin, the following criteria shall be used for judging the acceptability of results (95 % probability): 12.1.1 Single-Operator Precision--The single-operator standard deviation has been found to be 0.41°C (0.73°F). Therefore, results of two properly conducted tests by the same operator on the same sample of bitumen should not differ by more than 1.2°C (2.0°F). 7 12.1.2 Multilaboratory Precision--The multilaboratory standard deviation has been found to be 0.70°C (1.26°F). Therefore, results of two properly conducted tests on the

13. Keywords 13.1 asphalt; ball and ring; bitumen; coal tar; softening point

These numbers represent, respectively, the (IS) and (D2S) limits as described in Practice C 670.

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connechon with any item mentioned in this standard. Users o! this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reapproved or withdrawn, Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meebng of the responsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 100 Barr Harbor Drive, West Conshohocken, PA 19428.

53

( ~ , ) Designation:D 56 - 97a Standard Test Method for Flash Point by Tag Closed Tester 1 This standard is issued under the fixed designation D 56; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last renpproval. A superscript epsilon (e) indicates an editorial f~han~since the last revision or reapprovai.

This test method ha~ been approvedfor use by agencies of the Department of Defense. Consult the DoD Index of SpecOqcations and Standards for the specific year of issue which has been adopted by the Department of Defense. This test method has been adoptedfor use by gowrnment agencies to replaceMethod 1101 of Federal Test Method Standard No. 791b, and Method 4291 of Federal Test Method Standard No. 141A. INTRODUCTION

To ensure an acceptable precision, this dynamic flash point test employs a prescribed rate o f temperature rise for the material under test. The rate of heating may not in all cases give the precision quoted in the test method because of the low thermal conductivity o f certain materials. To improve the prediction of flammability, Test Method D 3941, which utiliT~s a slower heating rate, was developed. Test Method D 3941 provides conditions closer to equilibrium where the vapor above the liquid and the liquid are at about the same temperature. If a specification requires Test Method D 56, do not change to D 3941 or other test method without permission from the specifier. 1. Scope 1.1 This test method covers the determination of the Flash Point, by Tag manual and automated closed testers, of liquids with a viscosity below 5.5 mm2/s (cSt) at 40°C (104°F), or below 9.5 mm2/s (cSt) at 25"C (77°F), and a flash point below 93°C (200"F). 1.1.1 For the closed-cup flash point of liquids with the following properties: a viscosity of 5.5 mm2/s (cSt) or more at 40°C (104"1=); a viscosity o f 9.5 mm2/s (cSt) or more at 25°C (77°F); a flash point o f 93°C (200°F) or higher; a tendency to form a surface film under test conditions; or containing suspended solids, Test Method D 93 can be used. 1.1.2 For cut-back asphalts refer to Test Methods D 1310 and D 3143.

and cannot be used to describe or appraise the fire hazard or fire risk o f materials, products, or assemblies under actual fire conditions. However, results of this test can be used as elements of fire risk assessment which takes into account all of the factors which are pertinent to an assessment of the fire hazard of a particular end use. 1.3 Related Standards are Test Methods D 93, D 1310, D 3828, D 3278, and D 3941. 1.4 The values stated in SI units are to be regarded as standard. The values in parentheses are for information only. 1.5 This standard does not purport to address all of the

safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific

NOTE l--The U.S. Department of Transportation (RSTA)2 and U.S. Department of Labor (OSHA) have established that liquids with a flash point under 37.8"C (100"F) are flammable as determined by this test method for those liquids which have a viscosityless than 5.5 mm2/s (cSt) at 40"C (104"F) or 9.5 mm2/s (cSt) or less at 25"C (77°F), or do not contain suspended solids or do not have a tendency to form a surface film while under test. Other flash point classifications have been established by these departments for liquids using this test.

hazard statements see Note 4 and refer to Material Data Sheets.

Safety

2. R e f e r e n c e d D o c u m e n t s

2.1 A S T M Standards: D93 Test Methods for Flash Point by Pensky-Martens Closed Cup Tester3 D 850 Test Method for Distillation of Industrial Aromatic Hydrocarbons and Related Materials4 D 1015 Test Method for Freezing Points of High-Purity Hydrocarbons3 D 1078 Test Method for Distillation Range of Volatile Organic Liquids4 D 1310 Test Method for Flash Point and Fire Points of Liquids by Tag Open-Cup Apparatus 5

1.2 This standard can be used to measure and describe the properties o f materials, products, or assemblies in response to heat and flame under controlled laboratory conditions i This test method is under the joint jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommince 1302.08 on Volatility. Current edition approved May 10, 1997 and July 10, 1997. Published October 1997. Originally published as D 56 - 18 T. Last previous edition D 56 - 96. 2 For information on United States Department of Transportation regulations, see Codes of United States Regulation 49 CFR Chapter ! and for information on United States Department of Labor regulations, see Code of United States Regulation 29 CFR Chapter XVIL Each of these items are revised annually and may be procured from the Superintendent of Documents, Government Printing Office, Washington, DC 20402.

s Annual Book of ASTM Standards, Vol 05.01. 4 Annual Book of ASTM Standards, Vo106.04. s Annual Book of ASTM Standards, Vo106.01.

54

~[~ D 5e D 3143 Test Method for Flash Point of Cutback Asphalt with Tag Open-Cup Apparatus 6 D 3278 Test Methods for Flash Point of Liquids by Small Scale Closed Cup Apparatus 5 D3798 Test Method for Analysis of p-Xylene by Gas Chromatography 4 D3828 Test Methods for Flash Point by Small Scale Closed Tester7 D3941 Test Method for Flash Point by the Equilibrium Method with a Closed-Cup Apparatus s D4057 Practice for Manual Sampling for Petroleum and Petroleum Products 7 E 1 Specification for ASTM Thermometers s 2.2 Federal Test Method Standards: Method 1101, Federal Test Method Standard No. 791b 9 Method 4291, Federal Test Method Standard No. 141A9 2.3 ISO Standards: ° Guide 34 Quality Systems Guidelines for the Production of Reference Materials Guide 35 Certification of Reference Materials--General and Statistical Principles

4. Summary of Test Method 4.1 The specimen is placed in the cup of the tester and, with the lid closed, heated at a slow constant rate. An ignition source is directed into the cup at regular intervals. The flash point is taken as the lowest temperature at which application of the ignition source causes the vapor above the specimen to ignite. 5. Significance and Use 5.1 Flash point measures the tendency of the specimen to form a flammable mixture with air under controlled laboratory conditions. It is only one of a number of properties that must be considered in assessing the overall flammability ha,nrd of a material. 5.2 Flash point is used in shipping and safety regulations to define flammable and combustible materials. One should consult the particular regulation involved for precise definitions of these classes. 5.3 Flash point can indicate the possible presence of highly volatile and flammable materials in a relatively nonvolatile or nonflammable material. For example, an abnormally low flash point on a sample of kerosene can indicate gasoline contamination.

3. Terminology 3.1 Definition: 3.1.1 flash point--the lowest temperature corrected to a pressure of 101.3 kPa (760 mm Hg) at which application of an ignition source causes the vapors of a specimen of the sample to ignite under specified conditions of test. 3.1.1.1 Discussion--The specimen is deemed to have flashed when a flame appears and instantaneously propagates itself over the entire surface of the fluid. 3.1.1.2 Discussion--When the ignition source is a test flame, the application of the test flame may cause a blue halo or an enlarged flame prior to the actual flash point. This is not a flash and should be ignored. 3.2 Definitions of Terms Specific to This Standard: 3.2.1 dynamic (non-equilibrium)--in this type of flash point apparatus, the condition of the vapor above the specimen and the specimen are not at the same temperature at the time that the ignition source is applied. 3.2.1.1 Discussion--This is primarily caused by the heating of the specimen at the constant prescribed rate with the vapor temperature ]a~,~rtg behind the specimen temperature. The resultant flash point temperature is generally within the reproducibility of the method. 3.2.2 equilibrium--in that type of flash point apparatus or test method, the vapor above the specimen and the specimen are at the ~ m e temperature at the time the ignition source is applied. 3.2.2.1 Discussion--This condition may not be fully achieved in practice, since the temperature is not uniform throughout the specimen and the test cover and shutter is generally cooler.

6. Sampling 6.1 Erroneously high flash points will be obtained when precautions are not taken to avoid the loss of volatile material. Containers should not be opened unnecessarily, to prevent loss of volatile material and possible introduction of moisture. Transfers should not be made unless the sample temperature is at least 10"C (18"F) below the expected flash point. When possible, flash point must be the first test performed on a sample and the sample must be stored at low temperature. 6.2 Samples are not to be stored in plastic (polyethylene, polypropylene, etc.) bottles, since volatile materials may diffuse through the walls of the bottle. Samples in leaky containers are suspect and not a source of valid results and shall be discarded in accordance with local regulations for flammable materials. 6.3 At least 50 mL of sample is required for each test. Refer to sampling Practice D 4057.

7. Apparatus (Manual Instrument) 7.I Tag Closed Tester--The apparatus is shown in Fig. I and described in detailin Annex A I. 7.2 Shield--A shield460 m m (18 in.)square and 610 m m (24 in.)high, open in front,is recommended. 7.3 Thermometers--For the test cup thermometer, use one as prescribed in Table 1. For the bath thermometer, any convenient type that has an adequately open scale covering the required range may be used; it is often convenient to use the same type of thermometer as used in the test cup. NOTE 2--Whenever thermomete~ complying with ASTM require. ments ate not available, thermometers complying with the requirements for The Institute of Petroleum thermometer IP 15C PM-Low can be

used.

e Annua/Book ofASTM .,~nnd~'ds, Vol 04.03. ' Annua/Book o f A S T M , S ~ , Vo105.02. s Annua/Book ¢fASTM,S~andards, Vol 14.03. 9 Available from Supez~tendent of Document& U.S. Government Printing Office, Wmlfington, DC 20402. ,o Available from American National Standard11n~itute, II W. 42nd St., 13th Floor, New York, NY 10036.

8. Preparation of Apparatus (Manual) 8.1 Support the tester on a level steady table. Unless tests are made in a draft-free room or compartment, surround the tester on three sides by the shield for protection from drafts. 55

(~

D 56 by carefully lubricating the slide shutter with high-vacuum silicone lubricant.

Both Thermometer

Cup Thermometer

8.4 Verify the performance of the manual apparatus at least once per year by determining the flash point of a certified reference material (CRM), such as those listed in Annex A2, which is reasonably close to the expected temperature range of the samples to be tested. The material shall be tested according to the procedure of this test method and the observed flash point obtained in 9.5 shall be corrected for barometric pressure (see Section 13). The flash point obtained shall be within the limits stated in Table A2.1 for the identified CRM or within the limits calculated for an unlisted CRM (see Annex A.2). 8.5 Once the performance of the apparatus has been verified, the flash point of secondary working standards (SWSs) can be determined along with their control limits. These secondary materials can then be utilized for more frequent performance checks (see Annex A2). 8.6 When the flash point obtained is not within the limits stated in 8.4 or 8.5, check the condition and operation of the apparatus to ensure conformity with the details listed in Annex A1, especially with regard to tightness of the lid (A1.1.2), the action of the shutter, the position of the ignition source (AI. 1.2.3), and the angle and position of the temperature measuring device (A1.1.2.4). After any adjustment, repeat the test in 8.4 or 8.5 using fresh test specimen, with special attention to the procedural details prescribed in the test method.

\

Flame Size Bead

FlameTip / O=1 Chamber

Test Cup

Both

Bath Stand for Gas Burner

I~

9. Procedure (Manual) 9.1 Using a graduated cylinder and taking care to avoid wetting the cup above the final fiquid level, measure 50 :t: 0.5 mL of the sample into the cup, both the sample and graduated cylinder being precooled, when necessary, so that the specimen temperature at the time of measurement will be 27 + 5"C (80 + 10"F) or at least 10"C (18°F) below the expected flash point, whichever is lower. It is essential that the sample temperature be maintained at least 10"C (18°F) below the expected flash point during the transfers from the sample container to the cylinder and from the cylinder to the test cup. Destroy air bubbles on the surface of the specimens by use of knife point or other suitable device. Wipe the inside of the cover with a clean cloth or absorbent tissue paper; then attach the cover, with the thermometer in place, to the bath collar. 9.2 Light the test flame, when used, adjusting it to the size of the small bead on the cover. Operate the mechanism on the cover in such a manner as to introduce the ignition source into the vapor space of the cup, and immediately bring it up again. The time consumed for the full operation should be 1 s, allowing equal time periods for the introduction and return. Avoid any hesitation in the operation of depressing and raising the ignition source. When a flash is observed on the initial operation of the mechanism, discontinue the test and discard the result. In this case, a fresh sample shall be cooled an additional 10°C (18"F), below the original specimen installation temperature. 9.2.1 Care must be exercised when using a test flame, if the flame is extinguished it cannot ignite the specimen and the gas entering the vapor space can influence the result. When the flame is prematurely extinguished the test must be

Gas Burner

,

RG. 1 Tag ClosedFluh Tester(Ihnuell Tests are not to be made in a laboratory draft hood or near ventilators. 8.2 Natural gas and bottled gas flame and electric ignitors have been found acceptable for use as the ignition source. NOTE 3: Warning--Gas pressure should not be allowed to exceed 300 mm (11.8 in.) of water pressure. 8.3 For flash points below 13°C (55°F) or above 60"(3 (140°F), use as a bath liquid a 1+ 1 mixture of water and ethylene glycol (see Warning--Note 4). For flash points between 130C (55"F) and 600C (1400F), either water or a water-glycol mixture can be used as bath liquid. The temperature of the liquid in the bath shall be at least 10"C (18"F) below the expected flash point at the time of introduction of the sample into the test cup. Do not cool bath liquid by direct contact with dry ice (solid carbon dioxide). NOTe 4: Warning--EthyleneGlycol--Poison. Harmful or fatal if swallowed.Vapor harmful.Avoidcontactwith skin. NOTI~5--Due to possible difficultyin maintainingthe prescribed rate of temperatureriseand due to the formationof ice offthe lid, results by this methodfor sampleshavingflashpointsbelow0"C (32"F)may be unreliable. Trouble due to ice formationon the slidecan be minimized 56

~[~ D 56 discontinued and any result discarded. 9.3 Flash Points Below 60"C (140°F)--When the flash point of the sample is known to be below 60°C (140"F), apply and adjust the heat so that the temperature of the portion will rise at a rate of I°C (2°F)/min :1:6 s. When the temperature of the specimen in the test cup is 5°C (10"F) below its expected flash point, apply the ignition source in the manner just described in 9.2 and repeat the application of the ignition source after each 0.5°C (1 °F) rise in temperature of the specimen. 9.4 Flash Points at 60°C (140°F) or Above--If the flash point of the sample is known to be 60°C (140°F) or higher, apply and adjust the heat so that the temperature of the specimen will rise at a rate of 3°C (5°F)/min + 6 s. When the temperature of the specimen in the test cup is 5°C (10°F) below its expected flash point, apply the ignition source in the manner just described in 9.2 and repeat the application of the ignition source each l°C (2"F) rise in temperature of the specimen. 9.5 When the application of the ignition source causes a distinct flash in the interior of the cup, as defined in 3.1.1, observe and record the temperature of the specimen as the flash point. Do not confuse the true flash with the bluish halo which sometimes surrounds the ignition source during applications immediately preceding the actual flash. 9.6 Discontinue the test and remove the source of heat. the lid and wipe the thermometer bulb. Remove the test cup, empty, and wipe dry. 9.7 If, at any time between the firstintroduction of the ignition source and the observation of the flashpoint, the rise in temperature of the specimen is not within the specified rate, discontinue the test, discard the result and repeat the test,adjusting the source of heat to secure the proper rate of temperature rise,or using a modified "expected flash point," or both, as required. 9.8 Never make a repeat test on the same specimen of sample; always take fresh specimen of sample for each test.

TABLE 1

11mnnometem

For tests

Below 4=C (40°F)

Use ASTM 11'wacme~ '~

570 or (571=)

At 4 to 49°0 (40 to 120°F) 9(3 o¢ (gF) 57C or (57F)

A Gomplom ~,,;_~:~ueatiol~for these them~motem are ~

Above 49°C (120°F) 9(3 or (91=) In ~

El.

a certified reference material (CRM) such as those listed in Annex A2, which is reasonably close to the expected temperature range of the samples to be tested. The material shall be tested according to the procedure of this test method and the observed flash point obtained in 9.5 shall be corrected for barometric pressure (see Section 13). The flash point obtained shall be within the limits stated in Table A2.1 for the identified CRM or within the limits calculated for an unlisted CRM (see Annex A2.) I 1.2.4 Once the performance of the apparatus has been verified, the flash point of secondary working standards (SWSs) can be determined along with their control limits. These secondary materials can then be utilized for more frequent performance checks (see Annex A2). 11.2.5 When the flash point obtained is not within the limits stated in 11.2.3 or 11.2.4, check the condition and operation of the apparatus to ensure conformity with the details listed in Annex AI, especially with regard to tightness of the lid (Al.l.2), the action of the shutter, the position of the ignition source (Al.l.2.3), and the angle and position of the temperature measuring device (AI.I.2.4). After any adju,mnent, repeat the test in I 1.2.3 or 11.2.4 using fresh test specimen, with special attention to the procedural derails prescribed in the test method.

12. Procedure (Automated) 12.1 Adjust the external cooling system, if required, to a temperature necessary to cool the heating area 10"C below the expected flash point. 12.2 Place the test cup in position in the instrument. 12.3 When using a gas test flame, light the pilot flame and the test flame and adjust the test flame to 4 m m (5/32 in.) in diameter. If the instrument is equipped with an electrical ignition device, adjust according to the manufacturer's instructions. 12.4 Enter the Expected Flash Point; this will allow the heating area to be cooled to the required minimum starting temperature. NOTe 6---Toavoidan abnormal heating rate when the specimenis at a low temperature, it is recommendedto precoolthe test cup and cover. This may be accomplished by placing the assemblyinto position in the instrument while it is cooling to 10"C (18*F) below the programmed Expected ~ Point.

10. Apparatus (Automated Instrument) 10.1 An automated flash point instrument is used that is capable of performing the test in accordance with Section 9, Procedure (Manual) of the test method. The apparatus can use a gas test flame or electric ignitor. The dimensions for the test cup and test cover are shown in Figs. A 1.1 and A 1.2. 10.2 Samples with low flash point may require a source of cooling for the heating area. 11. Preparation of Apparatus (Automted Instrument) 11.1 Support the tester on a level, steady table. Unless tests are made in a draR-free compartment, it is a good practice, but not required, to surround the tester with a shield to prevent draft. 11.2 The user of the automatic instrument must be sure that all of the manufacturer's instructions for calibrating, checking, and operating the equipment are followed. 11.2.1 Adjust the detection system per manufacturer's instructions. 11.2.2 Calibrate the temperature measuring device per manufacturer's instructions. 11.2.3 Verify the performance of the automated apparatus at least once per year by determining the flash point of

NOTe 7--Flash Point results determined in an "unknown Expected Flash Point mode" should be considered approximate. This value can be

used as the ExpectedHash Point when a fresh specimen is tested in the standard mode of operation. 12.5 Using a graduated cylinder and taking care to avoid wetting the cup above the final liquid level, measure 50 + 0.5 mL of the sample into the cup, both the sample and the graduated cylinder being precooled, when necessary, so that the specimen temperature at the time of the measurement is 27 + 5"C (80 + 10"F) or at least 10"C (18"F) below the expected flash point, whichever is lower. It is essential that the sample temperature be maintained at least 10°C (18°F) 57

~

D 56

below the expected flash point during the transfers from the sample container to the cylinder and from the cylinder to the test cup. Destroy air bubbles on the surface of the specimen by use of knife point or other suitable device. Wipe the inside of the cover with a clean cloth or absorbent tissue paper; then attach the cover, with the temperature measuring device in place, to the bath collar. Connect the shutter and ignition source activator, if so equipped, into the lid housing. Readjust the size of the test flame or the setting of the electrical ignition device. Test the ignition source dipping action, if so equipped, and observe if the apparatus functions correctly. Press the start key. If a flash is observed upon initial operation, discontinue the test and discard the result. In this case a fresh specimen shall be cooled to an additional 10*C (18"17)below the original specimen installation temperature.

weather stations and airports, are precorrected to give sea level readings; these must not be used. 13.3 Report the corrected flash point to the nearest 0.5°C (or I°F). 14. Precision and Bias 14.1 Precision--The following criteria shall be used for judging the aceeptabifity of results (95 % probability): 14.1.1 Repeatability---The difference between successive test results, obtained by the same operator with the same apparatus under constant operating conditions on identical test material, would in the long run, in the normal and correct operation of the test method, exceed the following values only in one case in twenty: Flash Point,"(2('F) Rentability, "(2('F) Below 60"C(I40"F) 1.2"(2(2.0"F) At and Above60"C(138.2"F) 1.6"(2(3.0"F)

NOTE S---Careshould be taken when cleaning and positioning the lid assembly so not to damage or dislocate the flash detection system or temperature measuring device. See manufacturer's instructions for proper care and maintenance.

14.1.2 Reproducibility---The difference between two single and independent results, obtained by different operators working in different laboratories on identical test material, would in the long run, in the normal and correct operation of the test method, exceed the following values only in one case in twenty: Flash Point,"(2('F) Reproducibility,"12CF) Below60"(2(140"F) 4.YC (8"F) At and Above60"C(138.2"F) 5.8"(2(10"F) 14.2 Bias--The procedure in Test Method D 56 for measuring flash point has no bias since the Tag Flash Point can be defined only in terms of this test method. The current interlaboratory tests confirm that there is no relative bias between manual and automated procedures. In any case of dispute the flash point as determined by the manual procedure shall be considered the referee test. NOTE 9--Mixtures such as, but not limited, to those that are chlorinated or include water may cause there to be significantdifferences in the results obtained by manual and automatic instruments. For these mixtures, the precision statement may not apply. NoTE 10---The precision data were developed in a 1991 cooperative test programII using eight (8) samples. Twelve (12) laboratories participated with the manual apparatus and seventeen (17) laboratories participated with the automatic equipment. Information on the type of samples and their averageflashpointsare in the research report available at ASTM Headquarters.

12.6 The apparatus shall automatically control the test procedure as described in this test method. When the flash point is detected, the apparatus will record the temperature and automatically discontinue the test. If a flash is detected on the first application, the test should be discontinued, the result must be discarded and the test repeated with a fresh specimen. 12.7 When the apparatus has cooled down to a safe handling temperature (less than 55*(2 (130°F)) remove the cover and the test cup and clean the apparatus as recommended by the manufacturer. 13. Report 13.1 Correction for barometric pressure. Observe and record the ambient barometric pressure at the time and place of the test. When the pressure differs from 101.3 kPa (760 mm Hg), correct the flash point as follows: (1) Corrected flash point ffi C + 0.25 (101.3 - p) (2) Corrected flash point = F + 0.06 (760 - P) (3) Corrected flash point ffi C + 0.033 (760 - P) where: C ffi observed flash point, *C, F ffi observed flash point, *F, p = ambient barometric pressure, kPa, and P = ambient barometric pressure, m m Hg. 13.2 The barometric pressure used in this calculation must be the ambient pressure for the laboratory at the time of test. Many aneroid barometers, such as those used at

15. Keywords 15.1 combustible; fire risk; flammable; flash point; tag closed cup it Data is availablefromASTMHe~_dquarter~RequestRR:D02-1350.

58

~

D 56

ANNEXES (Mandatory Information) A1. APPARATUS AI.I The Tag closed tester shall consist of the test cup, lid with ignition source, and liquid bath conforming to the following requirements: A I.I.I Test Cup, of brass or other nonrusting metal of equivalent heat conductivity, conforming to dimensional requirements prescribed in Fig. AI.1. It shall weigh 68 + 1 g` AI.I.2 Lid: Al.l.2.1 The lid comprises a circle of nonmsting metal with a rim projecting downward about 15.9 mm (% in.), a slide shutter, a device which simultaneously opens the shutter and depresses the ignition source, and a slanting collar in which the cup-thermometer ferrule is inserted. Figure A 1.2 gives a diagram of the upper surface of the lid, showing dimensions and positions of the three holes opened and closed by the shutter, and the size and position of the opening for the cup thermometer. A1.1.2.2 The rim shall fit the collar of the liquid bath with a clearance not exceeding 0.4 mm (0.002 in.) and shah be slotted in such a manner as to press the lid firmly down on the top of the cup when the latter is in place in the bath. When this requirement is not met, the vertical position of the cup in the bath shall be suitably adjusted, as by placing a thin ring of metal under the flange of the cup. A1.1.2.3 The shutter shall be o~such size and shape that it covers the three openings in the lid when in the closed position and uncovers them completely when in the open position. The nozzle of the flame-exposure device, when

used, shall conform to the dimensions given in Table A I. I. The ignition source device shall be designed and constructed so that opening the shutter depresses the tip to a point approximately 2 mm (0.08 in.) to the right of the horizontal center of the middle opening of the lid (refer to lower part of Fig. AI.3). This will bring the ignition source to the approximate center of the opening` The plane of the underside of the lid shall be between the t o p and bottom of the t i p of the ignition source when the latter is fully depressed. A 1.1.2.4 The collar for the cup-thermometer ferrule shall be set at an angle which permits placement of the thermometer with its bulb approximately in the horizontal center of the cup, at a depth prescribed in Table A 1. I. Al.l.3 Liquid Bath, conforming to the limiting or minimum dimension shown in Fig. AI.3. It shall be of brass, copper, or other noncorroding metal of substantial construction. Sheet metal of about No. 20 B&S gage (0.812 ram) is satisfactory. It may, ff desired, be lagged with heat-insulating material to facilitate control of temperature. A I.I.4 Heater, of any type (electric, gas, alcohol, etc.) capable of controlling temperature as required in Section 9. An external electric heater, controlled by a variable voltage transformer, is recommended, AI.1.5 Bath Stand--For electric heating, any type of stand may be used. For alcohol lamp or gas burner, a stand, as illustrated in Fig` 1, to protect the ignition source from air currents (unless tests can be made in a draft-free room) is required.

~: 2.0 "=~----" 6 3 . 5 - - - - - ~

TABLE A1,1

Dimensional Requirements

Depth of I~Ul k~d surfacebelowtop of test cup

+o.Ts "---54.0

Depth of satn~e surface below top of test cup .J

Depth of bottom of bulb of test thermometerbelow

±0.5

top of cup when in place Insicle diameter of test cup

~'0.90 ~1.0

Diameter ol beacl on top of cover

+7,s

54.5

Diameter of opermg in tip of test flame nozzle

1

Outstcle diameter of tlp of test flame nozzle FIG. A1.1

Specimen Cup

59

27.8 + 0.4 mm (I .094 + 0.016 in. 29.4 + 0.8 mm (1.156 + 0.031 in. 45.0 ± 0.8 mm (1.77 ± 0.031 in. 54.0±0.1 mm (2.125 + 0.005 in. 4.0 + O.B rnm (0.156 -4- 0.031 in. 1.2 + 0.3 mm (0.049 + 0.010 in. 2.0 mm max (0.079 in. max)

D 56

+o

,iCJ

_ZJ

,"

I

A - - 7.15 mm B --

4.78 mm

C --

15.10 mm

D-

11.92 mm

E --

10.32 mm

Flame Size ~ Flame Size Bead U .~djustrn~i~t Burner~

Note: All dimensions!-0.13 mm unlessotherwiseshown. ,_ 2 0 . 6

/

i

# ~

Chamber

,

~k F - mm -'~, ,/

mm ,~ \~,~_

I 1 ~

ID-9 • •

84 mm •

, E E

Inch-Pound Equivalents mm 0.03 0.13 4.78 7.15 9.84

in. 0.001 0.005 0.188 0.281 0.387

mm 10.32 11.92 15.10 18.0 20.6

in. 0.406 0.469 0.594 0.71 0,81

NoTE--Dimensions relating to the size and position of the thermonteter colar are recommendedbut not mandatory. FIG. A1.2 Top of Ud Showing Position and Dimensions of Openings

95.3 mm Min. Dia.

In~-eoundSqulvslem

FIG. A1.3

60

mm

In.

6.4 82.6 95.3

0.25 3.25 3.75

Section of Liquid Bath end Test Cup (Manual Apparatus)

~

D 56

A2. VERIFICATION OF APPARATUS PERFORMANCE A2.1 Certified Reference Material (CRM)--CRM is a stable, pure (99+ mole % purity) hydrocarbon or other stable petroleum product with a method-specific flash point established by a method-specific interlabomtory study following ASTM RR:D02-1007 guidelines or ISO Guide 34 and 35. A2.1.1 Typical values of the flash point corrected for barometric pressure for some reference materials and their typical limits are given in Table A2.1 (see Note A2.3). Suppliers of CRMs will provide certificates stating the method-specific flash point for each material of the current production batch. Calculation of the limits for these other CRMs can be determined from the reproducibility value of this test method, reduced by interlaboratory effect and then multiplied by 0.7 (see Research Report RR:$15-1007).

NOTe A2.3---Materiah, purities, flash point values and limits stated in Table A2.1 were developed in an ASTM interlaboratory program (see RR:SIS-1010) to determine $uitability of use for verification fluids in

flash point test methods. Other natedals, purities, flash point values, and limi~l can be suitable when produced acoordin~ to the practices of

ASTM RR:D02-1007 or ISO Guides 34 and 35. Certificatesof performance of such materiah should be consultedbefore use, as the flash point value will vary dependent on the composition of each CRM batch. A2.2 Secondary Working Standard (SWS)---SWS is a stable, pure (99+ mole % purity) hydrocarbon, or other petroleum product whose composition is known to remain appreciably stable. A2.2.1 Establish the mean flash point and the statistical control limits (3#) for the SWS using standard statistical techniques. 12 NOTE A2.4---Thetypicalprocedureto arrive at the mean flashpoint is achieved by testing representative subsamples three times in an apparatus previouslyverifiedusing a CRM, statisticallyanalyzingthe results and, after outlier removal, calculatingthe arithmetical mean or by conductingan inteflaboratoryprogramwith three laboratories,each testing the representativesamplein duplicateand calculatingthe mean using standard statisticaltechniques.

NOTE A2.1--Supporting data for the interlaboratorystudy to generate the flash point in Table A2.1 can be found in research report RR:SI5-1010. TABLE A2.1

Hyemcmtxz n-decane n-undecam

D 56 Typical Flash Point VMues lind Typical Limits for CRM

Pumy(moteS)

FlashPo~t(°C)

Um~ (°f)

99+ 99+

50.9 67.1

:1:2.3 :e2.3

IsA S T M M N L 7 Manual on the Presen~ion of Dola ControlChart Analys~, 6th ed.,ASTM, 1990.

A3. CHECKING CONDITION CALIIIRATION AND OPERATION OF TAG CLOSED TESTER A3.1 Material: A3.1.1 1,4 Dimethylbenzene13 (p-Xylene), conforming to the following requirements: Specific gravity (15.6/15.6"C) (60/60"F), 0.860 min~ 0.866

A3.2 Procedure: A3.2.1 Determine the flash point of the 1,4 Dimethylbenzene, following the test procedures. When the tester is operating properly, a value of 27.2 :t: 0.6°C (81 :t: I°F) will be obtained. A3.2.2 When the flash point obtained on 1,4 Dimethylbenzene is not within the limits stated in A2.2.1, check the condition and operation of the apparatus to ensure conformity with the details listed in Annex A I, especially with regard to lightness of the lid (A1.1.2.2), the action of the shutter and the position of the ignition source (Al. 1.2.3), and the angle and position of the thermometer (Al.l.2.4). After adjustment, when necessary, repeat the test, with special attention to the procedural details prescribed in the test method. Also test a sample of Dimethylbenzene by gas chromatography to assure that it contains less than 500 ppm of Ca and hydrocarbons. Be sure to specify this level of purity.

max.

Boiling range . . . 2"C max from start to dry point, when tested by Test Method D 850 or Test Method D 1078. The range shall include the boiling point of pure 1,4 Dimethylbenzene, which is 138.4°C (281"F). Freezing p o i n t . . . 12.44°C (54.4°F), rain (99 % molal purity) as determined by Test Method D 1015. Contains less than 500 ppm of Ca and lighter hydrocarbons determined by gas chromatography using D 3798 (modified to allow reporting of Ce and fighter hydrocarbons) or a capillary boiling point column. n p-xylen¢obtainedfromany reputablechemicalsuppliermy be reed m calibratingfluidas longas theymeetthe _%~'scJ~,,mdetailedin A2.1.1.

A4. MANUFACrURING STANDARDIZATION A4.1 The cup thermometer, which conforms also to the specifications for the low-range thermometer used in the Pensky=Martens flash tester, Test Method D 93, is frequently supplied by the thermometer manufacturer with a metal or polytetrafluoroethylene ferrule intended to fit the collar on

the lid of the flash tester, This ferrule is frequently supple= mented by an adapter which is used in the larger=diameter collar of the Pensky=Martens apparatus, Differences in dimensions of these collars, which are immaterial in their effect on the result of tests, are a source of considerable

61

~ ) D 56

r.i

L.,

I I I

I

'I I

i I i

'I

I

I I I

I

I

!

f 5.3 mm

l

8.6 mm Dia. Min.

'

V"I __

!

Packing Ring

I

Soft Aluminum) 8.40 mm OD 7.23 mm ID 1.5 mm Thick

17.3 mm

I

]Y,;

-0.05 mm Inch-Pound Equivalents mm 0.05 5.3 7.1 FIG. A3.1

In. 0.002 0.21 0.28 Dimensions for Thermometer

mm 8.6 9.8 17.3

in. 0.34 0.385 0.68

Inch-Pound Equlv,,lents mm in. 1.5 0.06 7.23 0.284 8.40 0.3,30

Ferrule (Not Mandatory) FIG. A3.2

Dimensions for Thermometer

Mandatory)

Packing Ring (Not

A4. MANUFACTURING STANDARDIZATION unnecessary trouble to manufacturers and suppliers of instruments, as well as to users. A4.2 Subcommittee 21 on Metalware Laboratory Apparatus, of ASTM Committee E- 1 on Methods of Testing, has studied this problem and has established some dimensional requirements which are shown, suitably identified, in Figs. AI.I, A3.1, and A3.2. Conformity to these requirements is not mandatory but is desirable to users as well as suppliers of Tag closed testers.

A4.1 The cup thermometer, which conforms also to the specifications for the low-range thermometer used in the Pensky-Martens flash tester, Test Method D 93, is frequently supplied by the thermometer manufacturer with a metal or polytetrafluoroethylene ferrule intended to fit the collar on the lid of the flash tester. This ferrule is frequently supplemerited by an adapter which is used in the larger
62

~1~ D 56 The American $ooiaty for Testing and Materials takes no position respecting the validity of any patent rights asserted In connection with any item mentioned In this standard. Users of this standard are expresaly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, ere entirely their own responsibility. This standard Is subject to revision at any time by the responsible technical commlUes and must be reviewed every five years and if not ~ , alther respprovad or withdrawn. Your comments are Invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your oomments will receive careful consideration at a meeting of the responsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 100 Berr Harbor Drive, West Conshohockan, PA 19428.

63

(~)

Designation: D 86 - 96

An American NaUonal Standard

Standard Test Method for Distillation of Petroleum Products 1 This standard is issued under the fixed designation D 86; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in lxtrentheses indlcates the year of last reapproval. A superscript eix~lon (d indicates an editorial change since the last revision or reappmval.

This standard has been approved for use by agencies of the Department of Defense. Consult the DoD Index of Specifications and Standards for the specO°tcyear of issue which has been adopted by the Department of Defense.

D 5191 Test Method for Vapor Pressure of Petroleum Products (Mini Method) s D 5482 Test Method for Vapor Pressure of Petroleum Products (Mini Method-Atmospheric) 5 E 1 Specification for ASTM Thermometers ~ E 77 Test Method for Inspection and Verification of Thermometers 6 E 133 Specification for Distillation Equipment 7 IP 69 Determination of Vapour Pressure-Reid Method s IP 171 Vapour Pressure Micro Method 9

1. Scope 1.1 This test method covers the distillation of natural gasolines, motor gasolines, aviation gasolines, aviation turbine fuels, special boiling point spirits, naphthas, white spirit, kerosines, gas oils, distillate fuel oils, and similar petroleum products, utilizing either manual or automated equipment. 1.2 In cases of dispute, the referee test method is the manual test method prepared as directed for the indicated group. 1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are provided for information only. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

3. Terminology

3.1 Definitions of Terms Specific to This Standard: 3.1.1 decomposition point--the thermometer reading that coincides with the first indications of thermal decomposition of the liquid in the flask. 3.1.1.1 Discussion--Characteristic indications of thermal decomposition are an evolution of fumes, and erratic thermometer readings that usually decrease after any attempt is made to adjust the heat. 3.1.2 drypoint--the thermometer reading that is observed at the instant the last drop of liquid evaporates from the lowest point in the flask. Any drops or film of liquid on the side of the flask or on the thermometer are disregarded. 3.1.2.1 Discussion--The end point (final boiling point), rather than the dry point, is intended for general use. The dry point can be reported in connection with special purpose naphthas, such as those used in the paint industry. Also, it is substituted for the end point (finalboiling point) whenever the sample is of such a nature that the precision of the end point (final boiling point) cannot consistently meet the requirements given in the Precision Section. 3.1.3 end point or final boiling point--the maximum thermometer reading obtained during the test. This usually occurs after the evaporation of all liquid from the bottom of the flask. The term maximum temperature is a frequently used synonym. 3.1.4 initial boiling point--the thermometer reading that is observed at the instant that the first drop of condensate falls from the lower end of the condenser tube.

2. Referenced Documents 2.1 A S T M Standards: D323 Test Method for Vapor Pressure of Petroleum Products (Reid Method) 2 D 396 Specification for Fuel Oils2 D 850 Test Method for Distillation of Industrial Aromatic Hydrocarbons and Related Materials 3 D 975 Specification for Diesel Fuel Oils 2 D 1078 Test Method for Distillation Range of Volatile Organic Liquids 3 D 2892 Test Method for Distillation of Crude Petroleum (15-Theoretical Plate Column) 4 D4057 Practice for Manual Sampling of Petroleum and Petroleum Products 4 D 4177 Practice for Automatic Sampling of Petroleum and Petroleum Products 4 D 4953 Test Method for Vapor Pressure of Gasoline and Gasoline Oxygenate Blends (Dry Method) 5 D 5190 Test Method for Vapor Pressure of Petroleum Products (Automatic Method) 5 t This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct resl~nsibility of Subcommittee 1:}02.08 on Volatility. In the IP, this test method is under the jurisdiction of the Standardization Committee. Current edition approved Apr. 10, 1996. Published June 1996. Originally published as D 86 - 21. Last previous edition D 86 - 95. 2 Annual Book of ASTM Standards, Vol 05.0 I. 3 Annual Book of A~l'M Standards, Vol 06.04. 4 Annual Book of ASTM Standards, Vol 05.02. 5 Annual Book of ASTM Standards, Voi 05.03.

6 Annual Book OfASTM Standards, Vol 14.03. 7 Annual Book OfAA'TM Standards, Vol 14.02. t Available from The Institute of Petroleum, 61 New Cavendish St., London, WIM 8AR, England. 9 Withdrawn 1992, contact The Institute of Petroleum for availability.

64

~

D 86 NS 19/26

3.1.5 percent evaporated--the sum of the percent recovered and the percent loss. 3.1.6 percent loss--one hundred minus the percent total recovery.

3.1.7 percent recovered--the volume in millilitres of condensate observed in the receiving graduate, in connection with a simultaneous thermometer reading. 3.1.8 percent recoverymthe maximum percent recovered, as observed in accordance with 9.10. 3.1.9 percent residuemthe volume of residue in millilitres measured in accordance with 9.11. 3.1.10 percent total recovery---the combined percent recovery and residue in the flask, as determined in accordance with 9.12. 3.1.11 thermometer reading--the temperature of the saturated vapor measured in the neck of the flask below the vapor tube.

line Marking

4. Summary of Test Method 4.1 A 100 mL sample is distilled under prescribed conditions that are appropriate to its nature. Systematic observations of thermometer readings and volumes of condensate are made, and from these data, the results of the test are calculated and reported. Dimensions in mm

5. Significance and Use 5.1 The distillation (volatility) characteristics of hydrocarbons often have an important effect on their safety and performance, especially in the case of fuels and solvents. Volatility is the major determinant of the tendency of a hydrocarbon to produce potentially explosive vapors. It is also critically important for both automotive and aviation gasolines, affecting starting, warmup, and tendency to vapor lock at high operating temperature or at high altitude, or both. The presence of high boiling point components in these and other fuels can significantly affect the degree of formation of solid combustion deposits. 5.2 Volatility, as it affects rate of evaporation, is also an important factor in the application of many solvents, particularly those used in paints. 5.3 Petroleum product specifications generally include distillation limits to assure products of suitable volatility performance.

RG. l a

Distillation Flask with Ground Glass Joint

GO ~'

!

I

Knuded knob

•¢i ' ~'-"i~

if:

t

~

i i<
6. Apparatus 6.1 Unless noted otherwise, all of the section and figure reference numbers in 6.2 through 6.8 refer to Specification E 133, the specification to which all the items listed shall conform. 6.2 Flask--Flask A (100 mL), as shown in Fig. 3 (of Specification E 133) for natural gasolines. Flask B 0 2 5 mL), as shown in Fig. 1a of this test method or as shown in Fig. 3 (of Specification E 133) for all others. 6.3 Condert~er and Cooling Bath--Section 5, and Figs. 1 and 2 of Specification E 133. 6.4 Shield--Section 6, and Figs. l and 2 of Specification E 133. 6.5 Heater--Section 7, and Figs. l and 2 of Specification E 133. 6.6 Flask Support--Table 2 (of Specification E 133),

Cone 1:10 Male NS 19/26

I J /

,

/

,

,.6

PTI=E Centodno Device f = ground Glass Joint

Boards A 32-ram (1.25-in.) B 38-mm (l.5-in.) or C 50-mm (2-in.) hole. 6.7 Graduated Cylinder--Section 9; Graduate B, 100 mL, as shown in Fig. 4 of Specification E 133. The cylinder must have graduations at the 5 mL level and from 90 to 100 mL in 1-mL increments. For automatic apparatus, the cylinder shall conform to the physical specifications described in this section, with the exception of the graduations. 6.7.1 For automatic apparatus, the level follower/ recording mechanism of the apparatus will have a resolution of 0.1 mL with an accuracy of:l: 1 mL. The calibration of the assembly should be confirmed according to manufacturer's instructions at regular intervals. The typical calibration procedure involves verif~ng the output with the receiver containing 5 and 100 mL of material respectively. 65

~) D 86 6.8.2 The temperature sensor shall be mounted through a snug-fitting device designed to mechanically center the sensor in the neck of the flask. The use of a cork or silicone stopper with a hole drilled through the center is not acceptable for this purpose. Examples of acceptable centering devices are shown in Figs. l and 2.

Thermometer or PT-IO0 ..~

1 =i

Compression Nut

7. Sampling 7.1 Determine the GROUP characteristics that correspond to the sample to be tested (see Table l). Where the procedure is dependent upon the group the section headings will be so marked. 7.2 Sampling shall be done in accordance with Practice D 4057 or Test Method D 4177 and as described in Table 2. 7.2.1 GROUP 0--Collect the sample in a bottle previously cooled to 0 to 4.5°C (32 to 40°F) preferably by immersing the bottle in the liquid, where possible, and discarding the first sample. Where immersion is not possible, the sample shall be drawn off into the previously cooled bottle in such a manner that agitation is kept at a minimum. Close the bottle immediately with a tight-fitting stopper and place the sample in an ice bath or refrigerator to maintain the sample at that temperature. 7.2.2 GROUPS 1 and 2--Collect and maintain the sample as described in 7.2.1 at a temperature of 0 to 10°C (32 to 50"F). 7.2.3 GROUPS 3 and 4--Maintain the sample at ambient temperature. I f sample is not fluid at ambient temperature, it is to be maintained at a temperature of 11°C (20°F) above its pour point. 7.3 Samples of materials that visibly contain water are not suitable for testing. 7.3.1 GROUPS 0, 1, and 2--If the sample is not dry, obtain another sample that is free from suspended water for the test. 7.3.2 GROUPS 3 and 4--In cases where a water free sample is not practical, the suspended water can be removed by shaking the sample with anhydrous sodium sulfate or other suitable drying agent and separating it from the drying agent by decanting.

Threads

Compression O-Ring j~. e PTFE Body

m

I

"

}

./

I Neck of Distilling Flask

m m m

Double O-Rings 41 Viton or Perfluorof L, Elastomer.

Flask ID to be Precision Bore

FIG. 2 Centering Device for Straight-Bore Neck

6.8 Temperature Sensor--Section 10 of Specification E 133, ASTM Thermometers 7C (71=) and 8C (8F) or IP Thermometers 5C (low distillation) and 6C (high distillation) conforming to the IP Specifications for Standard Thermometers. Under certain test conditions the bulb of the thermometer can be 28"(3 (50°1=) above the temperature indicated, and at an indicated temperature of 371°C (700"1=) the temperature of the bulb is approaching a critical range in the glass. Thermometers that have been exposed to such conditions are not to be reused without checking their ice point to verify calibration as prescribed in Specification E 1 and Test Method E 77. 6.8.1 Temperature measurement systems using thermocouples or resistance thermometers must exhibit the same temperature lag and accuracy as the equivalent mercury in glass thermometer. Confirmation of the calibration of these temperature sensors is to be made on a regular basis. This can be accomplished potentiometricagy by the use of standard precision resistance, depending on the type of probe. Another technique is to distill pure toluene in accordance with Test Method D 850 and compare the temperature indicated with that shown by the above mentioned mercury in glass thermometers when carrying out a manual test under the same conditions. NOTE l--When running the test by the manual method, products with a low initialboilingpoint may have one or more readingsobscured by the centeringdevice. NOTe 2--Toluene is shown in reference manuals as boiling at 110.6"Cunder the conditionsof Test MethodD 1078 that uses a partial immersionthermometer.Becausethis test methodusestotal immersion thermometers the results will be lower and different with each. The approximate figures are Thermometer 7C (TF) or IP 5C at 109"C (228"F), and Thermometer8C (8F) or IP 6C at 110"C(230"F).

8. Preparation of Apparatus 8.1 Refer to Table 3 and prepare the apparatus as directed for the indicated group. Bring the temperature of the graduate, the flask, the temperature sensor, and the cooling bath to the indicated temperature. 8.2 Make any necessary provisions so that the temperature of the cooling bath and the graduate will be maintained at their respective temperatures. The cooling bath must have a liquid level above the highest point of the condenser. If necessary, make suitable provision for circulation, stirring, or air blowing to provide a uniform temperature throughout the bath. The graduate must be in a bath such that either the liquid level is at least as high as the 100 mL mark, or the entire graduate is surrounded by an air circulation chamber. 8.2. I GROUPS 0, 1, 2, and 3--Snitable media for low temperature baths include chopped ice and water, refrigerated brine, and refrigerated ethylene glycol. 8.2.2 GROUP 4--Suitable media for ambient and higher bath temperatures can include cold water, hot water, or heated ethylene glycol. 8.3 Remove any residual liquid in condenser tube by 66

~1~ D 8 6 TABLE 1 Group 0 Sample Characteristics: Distillate Type: Vapor pressure at 37.8°C, kPa 100°F, psi (Test Methods D 323, O 4953, D 5190, D 5191, D 5482, IP 69 or IP 171) Dlst~latlon, IPB °C •F EP °C •F

Group Characteristics Group 1

Group 2

Group 3

Group 4

> 65.5 > 9.5

< 65.5 < 9.5

< 65.5 < 9.5

< 65.5 < 9.5

s250 s482

~1~ s212 >250 > ~2

>1~ >212 >2~ >482

Group 3

Group 4

Natural Gasoine

s250 s482 TABLE 2

Sampling

Group I 0to10 32 to 50 0to10

Group 2

Temperature of Sample Bottle: oC °F Tempembxe of Stored Sarape: oC

Group 0 0 to 4.5 32 to 40 0 to 4.5

°F

32 to 40

32 to 50

32 to 50

Resample

Resample

Res~p~

If esmple Is wet:

~0 Flesk, ml. ASTM Dbthtion IP DisSlatkxl ~

~

Sup~xt Dt.mter of ho~, mm ~n.)

Temperature at start of Test: FIMk and thermometer, °C =F

Fmk ~ a o r t and ¢~e~ GrlKluate and 100 mL charge, oC °F

0to10

T~31W~l~ratlon~~s ~1

Ambient Ambient 11°C alx~ve pour point ~ Ambient 20eF above pour point Dry in _-l:~--~moe Dry in with 7.3.2 with 7.3.2

~2

~3

100

125

125

125

125

7c FF)

7C p'F)

7C FF)

7C (7F)

eC (eF)

5C A 32 (1.25)

5C B 38 (1.5)

5C B 38 (1.S)

5C C 50 (2.0)

6C C 50 (2.0)

13to is ss to65

Not'hOve amUent

Not ~ v e

...

13 tO 18 55 tO 65

13 tO llmblent 55 tO Ilnlblent

o to4.5

13to is

13to 18

32 to40 Not W~'¢

53 to 65 Not~

s6 to65 Not ~ o v e

0 tO 4.5 32 tO 40

~ 13 tO 18 55 tO 65

xm~nt 13 tO 18 55 tO 65

swabbing with a piece of soft, tint-free cloth attached to a cord or copper wire. 8.4 GROUPS 0, 1, 2, and 3--Fit a thermometer 7C (7F), prodded with a snug-fitting, well-rolled cork or siliconerubber stopper, tightly into the neck of the sample container and bring the temperature of the sample to the temperature indicated in Table 3. 8.5 Measure 100 mL of sample in the graduate and transfer as completely as practical the contents of the graduate to the distillation flask, taking care that none of the liquid flows into the vapor tube. 8.6 Fit the temperature sensor through a snug.fitting device designed to mechanically center the sensor in the neck of the flask. In the case of a thermometer, the bulb is centered in the neck and the lower end of the capillary is level with the highest point on the bottom of the inner wall of the vapor tube (see Fig. 3). In the case of thermocouple/ resistance thermometer, follow the manufacturer's instructions as to placement. 8.7 Fit the flask vapor tube, provided with a snug-fitting, well-rolled cork or silicone rubber stopper, tightly into the condenser tube. Adjust the flask in a vertical position and so that the vapor tube extends into the condenser tube for a distance of 25 to 50 mm (1 to 2 in). Raise and adjust the flask support board to fit snugly against the bottom of the flask. 8.8 Place the graduate that was used to measure the

~4

charge, without drying, into its bath under the lower end of the condenser tube so that the end of the condenser tube is centered in the graduate and extends therein for a distance of at least 25 m m (1 in), but not below the 100-mL mark. Cover the graduate closely with a piece of blotting paper, or similar material, that has been cut to fit the condenser tube snugly. 8.9 Record the room temperature and prevailing barometric pressure. Proceed at once with the distillation, as given in the Procedure Section.

w

RG. 3

67

Position of Thermometer in Distillation Flask

D 86 9. Procedure 9. I Apply heat to the distillationflask and contents. The heating at this stage must be so regulated that the time interval between the firstapplication of heat and the initial boiling point is as indicated in Table 4. 9.2 Observe and record the initial boring point. If a receiver deflector is not being used, immediately move the graduate so that the tip of the condenser touches its inner wall. 9.3 Regulate the heating so that the time from initial boiling point to 5 or I0 % recovered is as indicated in Table 4. 9.4 Continue to regulate the heating so that the uniform average rate of condensation from 5 or I0 % recovered to 5 m L residue in the flask is 4 to 5 m L per rain. 9.5 Repeat any distillationthat did not meet the foregoing conditions. 9.6 If a decomposition point is observed, discontinue the heating and proceed as directed in 9. I0. 9.7 In the interval between the initial boiling point and the end of the distillation,observe and record data necessary for the calculation and reporting of the results of the test as required by the specification involved, or as previously established for the sample under test. These observed data can include thermometer readings at prescribed percentages recovered, or percentages recovered at prescribed thermometer readings, or both. Record all volumes in the graduate to the nearest 0.5 or 0. I mL, and all thermometer readings to the nearest 0.5"C (l.0°F) or 0.1"C (0.1°F) as appropriate to the apparatus being used. 9.7.1 G R O U P 0--1n cases in which no specific data requirements have been indicated, record the initialboiling point, the end point (final boring point) and thermometer readings at each I0 % multiple of volume recovered from I0 to 90, inclusive. 9.7.2 G R O U P I, 2, 3, and 4--1n cases in which no specific data requirements have been indicated, record the initial boring point, the end point (final boring point) or dry point, or both, and thermometer readings at 5, 15, 85 and 95 % recovered, and at each 10 % multiple of volume recovered from 10 to 90, inclusive. TABLE 4 Group 0

9.7.3 If it is required to report the thermometer reading at a prescribed percent evaporated or recovered for a sample which has a rapidly changing slope of the distillation curve in the region of the prescribed percent evaporated or recovered reading, record temperature readings at more frequent intervals. Intervals as small as every 1% recovered may be required depending on the magnitude of the change of slope. The slope is considered rapidly changing if the Change in Slope (C) is greater than 0.6 [Change of Slope (F) is greater than l.O] as calculated by Eqs (1) and (2)]. Change of Slope (C) I

[(C= -- C|)/(V

2 -- V|)]

- - C,m]I)/(V~

-- [(C3

-- V = ) ]

([)

Change of Slope (F) - [(F, - F,)I(V z - V,)] - [(F, - F=)I(V, - V2)] (2) where: C! = Temperature at the volume % recorded one reading prior to the volume % in question, "(3, Temperature at the volume % recorded in question, "C, c 3 = Temperature at the volume % recorded following the volume % in question, °C, Temperature at the volume % recorded one reading F1 prior to the volume % in question, °F, F2 Temperature at the volume % recorded in question, "F, Temperature at the volume % recorded following the volume % in question, "F, v , = Volume % recorded one reading prior to the volume % in question, V2 = Volume % recorded at the volume % in question, and V3 ffi Volume % recorded following the volume % in question. 9.8 When the residual I/quid in the flask is approximately 5 mL, make a final adjustment of the heat so that the time from the 5 mL of liquid residue in the flask to the end point (final boiling point) shall be within the limits prescribed in Table 4. If this condition is not satisfied, repeat the test, with appropriate modification of the final heat adjustment. 9.9 Observe and record the end point (final boiling point) or dry point, or both, as required, and discontinue the heating. =

Conditions During Test Procedure Group I

Group 2

Group 3

Group 4

Temperature of cooling bathA, =C °F Temperature of bath around graduate, °C °F

0 to 1 32 to 34 0 to 4 32 to 40

0to1 32 to 34 13 to 18 55 tO 65

0to4 32 to 40 13 to 18 55 to 65

0to4 32 to 40 13 to 18 5§ to 65

0to60 32 to 140 :t 3 :1:5 of charge

Tlrne from first appfcatlon of heat to Initial boiling point, minutes Time from initial boiling point to 5 '~ recovered, seconds to 10 ~ moovemd, minutes Unlfotm everage rate of condensation from 5 'J; reoovemd to 5 mL residue In flask, mL/rnln Time reoorded from 5 mL resldua to end point, min

2 to 5

5to10

5tO10

5to10

... 3to4 4to5

60 to 75

60 to 75

o.

4to5

4to5

4to5

4to5

3to5

3~5

3~5

5max

5max

ta~0a~um

.

5to15

.

.

.

'~The ixoper condenser bath temperature wa depend upon the wax content of the sample and of Its distillation fractions. The minimum temperature that permlts satlsfacto~/opwstlon shall be used. In general, a bath tomperature In the 0 ~ 4°C (32 ~ 40°~ ~ ~~ ~ k ~ ~ ~ ~ ~ ~ ~ Grade No. I fuel olI as pmscrlbed in Sl)ecif~a~on D 396, and those meeting the speclflcatk:ns ~ ~ ~. I~ ~ ~ ~ ~ ~ ~~ D 975. ~ ~ cases involvlng Grade No.2 fu~ oi (see Speciflcatlon D 396), Grade No. 2.D dlesel fual oU (see S ~ t J o n D 975), gas oils and slmllar d l s ~ , ~ ~y ~ ~ to hold the condenser bath temperature at some point in the 38 to 60°C (100 to 140°F) range, in order to avoid the ¢o'¢lensatlon of solid waxy matodals in the condenm" tube.

68

~

D 86 IP Thermometer 5C can be reported in place of the obscured ASTM Thermometer 8C (8F) or IP Thermometer 6C readings, and the test report shall so indicate. If, by agreement, the obscured readings are waived, the test report shall so indicate. 10.3 Thermometer readings shall be corrected to 101.3 kPa (760 mm HI;) pressure except when product definitions, specifications, or agreements between the purchaser and the seller indicate, specifically, that such correction is not required or that correction shall be made to some other base pressure. This report shall include the observed pressure and shall state whether corrections have or have not been applied. When the report is based on thermometer readings corrected to 101.3 kPa (760 mm Hg), obtain the correction to be appfied to each thermometer reading by means of the Sydney Young equation as given in Eqs. 3, 4, or 5, or by the use of Table 5. For Celsius temperatures:

9.10 While the condenser tube continues to drain into the graduate, observe the volume of condensate at 2 min intervals until two successive observations agree. Measure this volume accurately, and record it, to the nearest 0.5 or 0. l mL as appropriate to the apparatus being used, as percent recovery. If the distillation was previously discontinued under the conditions of a decomposition point, deduct the percent recovery from 100, report this difference as percent residue and loss, and omit the procedure given in 9.11. 9.11 After the flask has cooled, pour its contents into a 5 mL graduated cylinder, and with the flask suspended over the 5 mL graduate, allow the flask to drain until no appreciable increase in the volume of liquid in the 5 mL graduate is observed. 9.11. l GROUP 0--Cool the graduate to 0 to 4.5"C (32 to 40"F). Record the volume in the graduate, to the nearest 0.1 mL, as percent residue. 9.11.2 GROUPS 1, 2, 3, and 4---Record the volume in the graduate, to the nearest 0.1 mL, as percent residue. 9.12 The sum of the percent recovery (see 9.10) and the percent residue (see 9.11) is the percent total recovery. Deduct the percent total recovery from 100 to obtain the percent loss.

where: C# and

"C

"F

10 tO 30 30 to 50 50 to 70 70 to 90 90to 110 1I0 to 130 130 to 150 150 tO 170 170 to 190 190 tO 210 210 to 230 230 to 250 250 to 270 270 tO 290 290 to 310 310 tO 330 330 to 380 350 tO 370 370 tO 390 390 to 410

50 to 86 86 to 122 122 to 158 158 to 194 134 to 230 230 tO 266 266 to 302 302 to 338 338 to 374 374 to 410 410 to 446 446 to 462 482 to 518 518 to 554 554 to 590 590 to 626 638 tO 982 662 tO 698 698 to 734 734 to 770

t:)

(5)

C/:

TABLE 6

A per 1.3 kPa (10 mm) Dlfbmnce fn _Pr,~,_ _ ,re "C "F 0.35 0.38 0.40 0.42 0.46 0.47 0.50 0.52 0.54 0.57 0.59 0.62 0.64 0.66 0.69 0.71 0.74 0.78 0.78 0.81

0.00012 (760 - PX4~o +

corrections tO be added algebraically to the observed thermometer readings t# or th respectively, Pk = barometric pressure, kPa, prevailing at the time and location of the test, and P : barometric pressure, mm H~, prevailing at the time and location of the test. After applying the corrections and rounding each result to the nearest 0.5"C (1.0"F) or 0.1"C (0.1"F) as appropriate to the apparatus being used, use the corrected thermometer readings in all further calculations and reporting. 10.4 After barometric corrections of the thermometer readings have been made, if required (see 10.3), the following data require no further calculation prior to reporting: initial boiling point, dry point, end point (final boiling point), decomposition point, and all pairs of corresponding values

Approximate Thermometer Reading Corrections ~

(4)

c:-

10.1 For each test, calculate and report whatever data are required by the specification involved, or as previously established for the sample under test (see 9.7). Report all percentages to the nearest 0.5 or 0.1, and all thermometer readings to the nearest 0.5"C (I.0"F) or 0.1"C (0.1"F) as appropriate to the apparatus being used. Report the barometric pressure to the nearest 0.1 kPa (l mm Hg). 10.2 GROUP 4--When ASTM Thermometer 8C (SF) or IP Thermometer 6C is used in testing aviation turbine fuels and similar products, pertinent thermometer readings can be obscured by the cork. To provide the desired data, a second distillation according to Group 3 may have to be performed. In such cases, reading from ASTM thermometer 7C (7F) or

Temperature Range

(3)

For Fahrenheit temperatures:

10. Calculations and Report

TABLE 5

C c - 0.0009 (I01.3 - Pk)(273 + tc) Cc = 0.00012 (760 - PX273 + tc)

Values of Constants A and B Used in Obtaining Corrected DlsUllation Le_-_-

Otwn~d EWm~etflc P r m g n kPa mm Hg

0.63 0.98 0.72 0.76 0.81 0.85 0.90 0.94 0.98 1.03 1.06 1.12 1.15 1.19 1.24 1.28 1.33 1.37 1.40 1.46

74.6 76.0 77.3 78.6 50.0 81.3 82.6 84.0 e5.3 86.6 88.0 89.3 90.6 92.0 93.3 94.6 96.0 07.3 98.0 100.0 101.3

A TO be added when Imromelrlc pmuure Is below I01.3 kPa (750 mm l-lg); to be subtrm:~Kl when ~ pmuure Is AbOVeI01.3 IdNi (750 mm Hg).

69

560 57O 580 580 500 610 620 630 640 650 660 670 680 690 700 710 720 730 740 750 760

A

B

0.231 0240 0~58 0.261 0.273 0.286 0.300 0.316 0.333 0.353 0.375 0.400 0.428 0.461 0.500 0.545 0.50O 0.687 0.750 0.857 1.000

0.384 0.38O 0.375 0.369 0.363 0.357 0.350 0.342 0.333 0.323 0.312 0.300 0.286 0.269 0,250 0.227 O2OO 0.166 0.125 0.071 0.000

D 86 TABLE 7

involving percentages recovered and thermometer readings. 10.5 When thermometer readings are corrected to 101.3 kPa (760 mm Hg) pressure, the actual loss shall be corrected to 101.3 kPa (760 mm Hg) pressure, according to the following equation: L c ffi A L + B (6)

Repeatability and Reproducibility for Group 1 (Manual)

Evaporated Point

where: L

ffi percent loss as calculated from test data, Lc = corrected loss, and A and B = numerical constants. 10.5.1 The values of A and B that depend upon the prevailing barometric pressure are listed in Table 6. The following equation can be substituted: Lc ffi {(L - 0.499287)/(13.65651 - 0.12492914 Pk)} (7) + 0.4997299 Lc ffi ((L - 0.499287)/(13.65651 - 0.01665174 P)} (8) + 0.4997299

Repeatab~llty A *C °F

ReWoduclbMtyA °C °F

IBP 5',r,

3.3 ro + 0.66

6 re + 1.2

5.6 Ro + 1.11

10 Ro + 2.0

10 to80% 90 ~; 95 •

ro ro ro

ro ro ro

Ro Ro - 1.22 Ro - 0.94

Ro Ro - 2.2 Ro - 1.7

FBP

3.9

7

7.2

13

• Read ro and Ro from the graph ln either Ftg. 4 ('C) or Ftg. 5 ('F).

dures, and indicate on the report whether the graphical procedure or the arithmetical procedure has been used. 10.8.1 A r i t h m e t i c a l P r o c e d u r e . - - D e d u c t the observed distillation loss from each prescribed percentage evaporated in order to obtain the corresponding percentage recovered. Calculate each required thermometer reading as follows: T= Tt.+

where: L = percent loss as calculated from test data, Lc ffi corrected loss, Pk ffi pressure, kPa, and P = pressure, mm Hg. 10.5.2 The corresponding corrected percent recovery is calculated according to the following equation: R c ffi R + ( L - L¢) (9)

(T+l - T L X R - RL)

RH - Rl,

(11)

where: R ffi percent recovered corresponding to the prescribed percent evaporated, R H = percent recovered adjacent to, and higher than R, RL - percent recovered adjacent to, and lower than R, T ffi thermometer reading at the prescribed percent evaporated. TH ffi thermometer reading recorded at RH and T L = thermometer reading recorded at R L. Values obtained by the arithmetical procedure are affected by the extent to which the distillation graphs are nonlinear. Intervals between successive data points can, at any stage of the test, be no wider than the intervals indicated in 9.7. In no case shall a calculation be made that involves extrapolation. 10.8.2 Graphical P r o c e d u r e - - U s i n g graph paper with uniform subdivisions, plot each thermometer reading corrected for barometric pressure, if required (see 10.3), against its corresponding percent recovered. Plot the initial boiling point at 0 % recovered. Draw a smooth curve connecting the points. For each prescribed percent evaporated, deduct the distillation loss, in order to obtain the corresponding percent recovered, and take from the graph the thermometer reading which this percent recovered indicates. Values obtained by graphical interpolation procedures are affected by the care with which the plot is made.

where: L = observed loss, Lc ffi corrected loss, R -- observed recovery, and Rc ffi corrected recovery. 10.5.3 When the thermometer readings have not been corrected to 101.3 kPa (760 mm Hg) pressure, the percent residue and percent loss are to be reported as observed in accordance with 9.11 and 9.12 respectively. 10.5.4 When reporting data, state whether the corrections have or have not been applied. 10.5.5 The corrected loss shall not be used in the calculation of percentages evaporated. 10.6 It is advisable to base the report on relationships between thermometer readings and percentages evaporated in any case in which the sample is a gasoline, or any other product classed under GROUP 1, or in which the percent loss is greater than 2.0. Otherwise, the report can be based on relationships between thermometer readings and percentages evaporated or recovered. Every report must indicate dearly which basis has been used. 10.7 To report percentages evaporated at prescribed thermometer readings, add the percent observed loss to each of the observed percentages recovered at the prescribed thermometer readings, and report these results as the respective percentages evaporated, that is: P, = P, + L (10)

NOTE 3--See AppendixX ! for numericalexamplesillustratingthese arithmeticalprocedures. I I. Precision and Bias

II. I The precision of this test method as determined by the statistical examination of interlaboratory test results is described below. Table A I. I lists which tables and figures are to be used for the different fuel groups, distillation methods, and temperature scales. 11.2 Repeatability: I 1.2. I GROUP 0--With proper care and strict attention to details, duplicate results obtained for endpoint should not differ from each other by more than 3.5"C (6"F). Differences in duplicate temperature readings for each prescribed percentage point should not exceed the amounts equivalent to 2 mL of distillate at each point in question.

where: L -- observed loss, Pe ffi percentage evaporated, and P, = percentage recovered. 10.8 To report thermometer readings at prescribed percentages evaporated, use either of the two following proce70

41~ D 86 11

10-

J

J ..

/,//~

7 ~

J f

j

,/

6~

l

f

4 ~

J

2

/

IlL

J

J

3

f

II.

j~

4

J

10

J

I/" J

J

11

f

f

J

f

I

3

f

:t

j

J

~

I 0

0 0.5

I.O

1.5

2.0

2.5

3.0

3.S

O.S

4.0

1~

1A

3.~

NOTE--

ro - 0.864 (°C/V %) + 1.214 (14) ,, 1.736 (°C/V %) + 1.994 (15) GROUP lmRepeatability, r o and Reproducibility, Res°

NOTE--

Ro

FIG. 4

FIG. 6

Z2,

:'Z

20.

Z0

J

3JI

/

10

.J

O z..

_ I

8

J

$

Ro /

O¢ 12

8

4

j

f

S

va

j

4

Z

ro

NOTE m

FIG. S

2

s

3

4

S

6

F/V%

Y

0

ro

0

I

1

0

%) + 2.186 (18) %) + 3.589 (17) GROUP l mRepeatabiUty, r o and Reproducibility, R¢s°

r o - 0.864 (°F/V Ro - 1.736 (°F/V

7

Repeatability and Reproducibility for Group 1 Repeatab~ A °C °F

ReproducibilityA °C °F

IBP

3.9

7

7.2

13

5 %

r o + 1.0 r o + 0.56

r o + 1.8 ro + 1.0

Ro + Ro +

Ro +

10 % 20 % 30 to70% 80 % 90%

95 % FBP

ro

ro

1.78 0.72 Ro + 0.72

ro ro ro r o + 1.4

ro ro ro ro +

Ro R o - 0.94 Ro-1.9 Ro

Ro Ro - 1.7 Ro-3.5 Ro

4.4

8

8.9

16

2.5

"ReadroandRofrOmU~egraphIn ~th~

F~.

3

4

5

G

?

8

9

ro - 0.673 ('F/V Ro - 1.998 (*F/V

%) + 2.036 (20) %) + 4.711 (21) GROUP 1--Repeatability, re and Reproducibility, Rols TABLE 9 Repeatability and Reproducibility for Groups 2, 3, and 4 ( A u t o m a t )

(A.tom~) Evaporated Point

2

F/V%

NOTE.~ FIG.

TABLE 8

l

f

l

2

0 0

4,8

f

J

.J

14 O

Ro

4JI

r o - 0.873 (°C/V %) + 1.131 (18) Ro - 1.998 {°C/V %) + 2.617 (19) GROUP 1--Repeatability, ro l i n d Reproducibility, Ross

16 --

f

t4, 12

O t.

3.0

15

18.

o

¢4i

"C/V~

"CIV%

S

3.2 Ro + 1.3 Ro + 1.3

R(meatab~A

ReWodudb~A

Colected

°C

°F

°C

°F

IBP 2% 5% 10% 20 to 70 % 80% 90 to 95 % FBP

3.5 3.5 1.1 + 1.08 S 1.2 + 1.42S 1.2 + 1.42 S 1.2+1.425 1.1 + 1.08 S 3.5

8.3 6.3 2.0 + 1.08 S 2.2+1.425 2.2 + 1.42 S 2.2+1.425 2.0 + 1.08 S 6.3

8.5 2.6 + 1.92 S 2.0 + 2.53 S 3.0+2.645 2.9 + 3.97 S 3.0+2.645 2.0 + 2.53 S 10.5

15.3 4.7 + 1.92 $ 3.8 + 2.53 S 5.4+2.645 5.2 + 3.97 S 5.4 + 2.94 S 3.6 + 2.53 $ 18.9

A S IS the ilverage idope calculated In _.wx~darce ___ wflh 11.4.

5 (o¢)or Rg. 7 ('F).

twenty.

11.2.2 GROUP 1--The difference between successive results obtained by the same operator with the same apparatus under constant operating conditions on identical test material would, in the long run, in the normal and correct operation of this test method, exceed the values indicated in Table 7 (Manual) or Table 8 (Automatic) in one case in

11.2.3 GROUPS 2, 3, and 4--The difference between successive results obtained by the same operator with the same apparatus under constant operating conditions on identical test materials would in the normal and correct operation of this test method, exceed the values indicated in

91

~ R(P(ATAIllLITY

D 86

RLrpRoDucIBILITY

R(P(ATABILIT Y

REPRODUCIBILITY -8

'7

'[ 'I

. •

'-.0

£

s-

5

4

3

"1

o •"J 1

E

T P

I

I~ E T

0

(

T

P

!

(

T

P

P NOTE~ I .= ~

NOTE---I " Initial boiling point, °C, E .. end poklt (final boiling point) or dry point, oC, T = thermometer reading at Wescdbed percent evaporated or recovered0 "C, and P -- pe,-~nt evaporated or recovered at prescribed thermometer reading, °C. FIG. 8 Groups 2, 3, 4 - - M a n u a l Method-Celsius Preclslon of Distillation Test Method O 86 - IP 123

boiling point, °F,

E = end Point(f~J ~

p~nt) or dry p~nt, °F,

T = thermometer reading at prescribed percent evaporated or recovered, °F, and P - percent evaporated or recovered at prescribed thermometer reading, °F. FIG. 9 Groups 2, 3, 4 ~ M a n u a l Method-Fahrenheit Precision of Distillation Test Method D 86 - IP 123

of change in thermometer readings in degrees Celsius (Fahrenheit) per the percentage recovered, at any point between the 10 and 90 % point, is assumed to be the same as the average rate between two data points that are equidistant above and below the point in question. The span from the point in question to either of the other data points does not represent more than 10 % recovered in any case, nor more than 5 % if the point in question is the 5 % point. Precision values for typical values of slope for GROUPS 2, 3, and 4 (Automatic) are given in Table 10. 11.4.1 The equations that follow are used as guidelines in calculating C/V % (F/V %). In the event the distillation end point occurs prior to the 95 % point, then appropriate modifications to the use of these equations must be made. 11.4.2 For Group 1 in the manual method and for all groups in the automatic method, the initial boiling point and end point do not require C/V % (F/V %). 11.4.3 For Groups 2, 3, and ~; in the manual method, the rate of change in thermometer readings in degrees Celsius per percentage recovered should be calculated from the nearest reading (5 % in the case of the IBP, and either 90 or

Fig. 8 (Manual, °C) or Fig. 9 (Manual, "F) or Table 9 (Automatic) in one case in twenty. 1°'1s

11.3 Reproducibility: 11.3.1 GROUP l m T h e difference between two single and independent results obtained by different operators working in different laboratories on identical test material would in the normal and correct operation of this test method, exceed the values indicated in Table 7 (Manual) or Table 8 (Automatic) in one case in twenty. 11.3.2 GROUPS 2, 3, and 4--The difference between two single and independent results obtained by different operators working in different laboratories on identical test material would in the normal and correct operation of this test method, exceed the values indicated in Fig. 6 (Manual, "C) or Fig. 8 (Manual, "F) or Table 9 (Automatic) in only one case in twenty, t°.st 11.4 To facilitate the use of the tables and figures, the rate ~oTest Method D 86 Manual Method North American and IP Lat~ '~ Test Method D 86 Automatic Method North American and IP L a ~

72

@

D 86

95 % in the case of FBP) and the corresponding IBP or FBP. 11.4.4 5 % recovered is calculated as follows:

TABLE 10

C/V%, F/V% 0.1(Tm - TIBP) (12) 11.4.5 10 tO 80 % recovered is calculated as follows: C/V%, FlY% -- 0.05(T(v+lo) - T(v_lo)) (13) 11.4.6 90 % recovered is calculated as follows: C/V%, FlY% 0.1(Tgo ?'so) (14) 11.4.7 95 % recovered is calculated as follows: (15) C[V%, F/V% = 0.2(7"95 - T9o) where: C/V% = rate of change in temperature at the volume percent in question, *C, F/V% = rate of change in temperature at the volume percent in question, *F, and T = temperature at the percent volume recovered indicated by the subscript, *C or *F, subscripts: V = volume percent recovered in question, V - I0 = 10 % less than volume percent in question, V + I0 = I0 % more than volume percent in question, and IBP, 5, I0, 80, 90, 95 = appropriate volume percent indicated. 11.5 Bias: I 1.5. l Absolute Bias--Due to the use of total immersion thermometers or temperature sensing systems designed to emulate them, the distillation temperatures in this test method are somewhat lower than the true temperature. The amount of absolute bias has not been determined.

Collect~

:

=

20 to 70 •

10 and 80 Y.

- -

5, 90, and 95 ~.

2~

IBP FBP

Observed Precision Values for Typical Values of Slope Groups 2, 3, and 4 (AutomaUc) Slope *C/XV *F/XV 0,5 1,0 1.5 2.0 2.5 0.5 1.0 1.5 2.0 2~ 1.0 2.0 3.0 4.0 2.0 3.0 4.0 5.0 ...... ......

0,9 1.8 2.7 3.6 4.5 0.9 1.8 2.7 3.6 4.5 1.8 3.6 5.4 7.2 3.6 5.4 7.2 9.0

Summary of Aids for Definition of Repeatability and Reproducibility Distillation Method

Temperature Scale *C or =F

11.2.1

1

Manual or Automatic Manual

1

Automatic

2,3,4

Manual

2,3,4

Automatic

=C OF °C °F °C OF °C °F

Table 7 and Fig. 4 Table 7 and Fig. 5 Table 8 and Fig. 6 Table 8 and Fig. 7 Fig. 8 Fig. 9 Tables 9 or 10 Tables 9 or 10

0

1.5 2.5 3,0 4,0 4.5 1.5 2.5 3.0 4.0 4.5 2.0 3.0 4.0 5.0 3.5 3.5 3.5 3.5 3.5 3,5

4.5 6.5 8.5 10.5 12.5 4.0 5.5 7.0 8.0 9.5 4.5 7.0 9.5 12,0 6.0 8.0 10.0 12.0 8.5 10.5

2.7 4,5 5,4 7.2 8.1 2.7 4.5 5.4 7.2 8.1 3.6 5,4 7.2 9.0 6,3 6.3 8.3 6.3 6.3 6.3

12. Keywords 12.1 distillates; distillation; petroleum products

(Mandatory Information)

Group

Re~ucl~l~ *C *F 8.1 11.7 15.3 18.9 22.5 7.2 9,9 12.6 14.4 17.1 8.1 12.6 17.1 21.6 10.8 14.4 16.0 21.6 15,3 18.9

11.5.2 Relative Bias--There exists a bias between the empirical results of distillation properties obtained by this test method and the true boiling point distillation curve obtained by Test Method D 2892. The amount of relative bias between the two test methods has not been determined. 11.5.2.1 Groups 1, 2, 3, and 4mRefer to Tables AI.2 A I.3, and A 1.4 for the statement of bias between automatic and manual apparatus.

ANNEX

TABLE A1.1

Repeatabll~ *C *F

73

Table, Section, and Figure to Use

(~) D 86 TABLE A1.2 Condensed Summary of C o m p a r a t i v e Manual and Automatic Distillation Results NOTE---All thermometer readings were oerrected to 101.3 kPa (760 mm Hg) pressure. The left-hand figures were manually obtained, and the right-hand figures represent commpond~g resu~ from the automatic apparatus. Celsius Gaso/ine.--Twenty six laboratories and fourteen samples (see Table A1.3) Kerosine--Eight tests in four laboratories for manual, and six tests in three laboratodes for automatic 176.5, 174.5 193.5, 193 215.5, 215.5 248, 248.5 171.5, 172 191, 193.5 213.5, 214 245.5, 248.5 174.5, 173.5 191.5, 191.5 214.5, 214.5 245, 247 Diesel Fuel--Ten tests in five laboratorkls for manual and for autornat~ 190.5, 189 215, 218 268.5, 269 322, 323 179.5, 179.5 208.5, 208.5 264, 264 318, 316 185.5, 134.4 213, 214 266, 266 319.5, 318.5 Fahrenheit

Max Min Average Max MIn Average

268, 268.5 264, 265 265.5, 268.5 341.5, 343 337, 338.5 340, 340,5

Gasoline---Twenty six laboratories and fourteen samples (See Table A1.4) Initial Boiling 10 • 50 ~ 90 • Point Evaporated Evlq~xlltsd Evaporated Keros/ne---EIght tests In four labomtodw for manual, and six tests In three laboraterles for automatlo 350, 346 380, 379 420, 420 478, 479 341,342 376, 375 416, 417 474, 476 346, 344 377, 377 418, 418 475, 477 D/ese/Fue/s Ten tests in five laboratories for manual and for lutomatlo 375, 372 419, 424 515, 516 612, 613 355, 355 407, 407 507, 507 804, 601 366, 364 415, 417 511,511 607, 605

Max M~ Average Max Min Average

TABLE A1.3

End Point (Final Boiling Point) 514, 515 507, 509 510, 512 647, 649 639, 641 644, 645

Bias B e t w e e n Methods (ADA-Manual) °C (Based on A v e r a g e s of ABTM and IP Data)

Sample

IBP

5~

10~;

20S

30"~

408

50~

60~

70~

80S

90~

95~

FBP

1 2 3 4 5 6 7 8 9 10 11 12 13A 14A

+1.1 (+0.9) +0.7 +0.3 +0.5 +1.2 +0.3 +0.3 +1.7 +1.5 +0.9 +1.0 +0.3 +0.5

+1.9 (0.0) +1.4 +0.6 +1.3 +1.2 +0.8 +0.5 +2.0 +1.6 +1.1 (+2.4) a +0.3 +0.4

+2.2 +0.8 +1.6 +0.8 +1.3 +1.6 +0.8 +0.7 +1.8 +1.2 +1.2 +2.3 +0.4 +0.7

+1.6 +0.5 +1.0 +0.8 +1.3 +1.2 +0.7 +0.6 +1.5 +0.7 +0.8 +1.2 +0.3 +0.5

+1.4 +0.4 +0.8 +0.3 +1.2 +1.2 +0.8 +0.7 +1.5 +0.4 +0.7 +1.2 +0.2 +0.8

+0.7 +0.6 +0.6 +0.7 +1.0 +1.1 +0.8 +1.2 +1.5 +0.5 +0.6 +1.2 +0.9 +1.1

+0.8 +0.2 +0.3 +0.5 +0.9 +0.8 +1.0 +1.2 +1.2 +0.9 +1.1 +1.2 +1.4 +1.7

+0.7 +0.1 +0.1 +0.8 +0.6 +1.1 +1.5 +1.1 +0.9 +1.0 +1.0 +0.9 +1.0 +1.7

+0.7 +0.1 +0.2 +1.1 +0.8 +1.2 +1.6 +1.3 +1.3 +1.4 +0.4 +1.1 +0.1 +1.0

+0.1 +0.4 +0.8 +1.2 +1.0 +0.2 +1.6 +1.9 +0.8 +1.9 +0.5 +02 +1.1 +0.8

+0.4 (+4.7)a +0.5 +0.8 +0.4 -0.1 +1.5 +1.1 -0.4 +0.9 -0.4 -0.7 +1.2 +0.3

+0.7 (+1.3)m +0.1 t-0.8 +0.4 +02 +1.7 +1.2 +0.4 +0.1 +0.1 (-0.8) I +1.0 0.0

-0.4 (-1.2) n -0.8 -0.9 -0.8 -0.3 -0.7 -0.8 -1.2 -2.1 -0.8 -0.9 -1.2 -0.8

1 2 3 4 5 5 7 8 9 10 11 12 13A 14A

A (3esOI~s. a ( ) Points not Inolucled in the wedal(~ analysis. TABLE A1.4

Bias B e t w e e n Methods (ADA-Manual) °F (Based on A v e r a g e s of ASTM and IP Data)

Sample

IBP

5•

10 "/,

20 Ii

30 I~

40 ~;

50 ~

60 S

70 S

80 ~

90 ~

95 •

FBP

Sample

1 2 3 4 5 6 7 8 9 10 11 12 13A 14A

+1.9 (+1.6)m +1.2 +0.5 +0.9 +2.1 +0.6 +0.6 +3.1 +2.7 +1.6 +1.8 +0~ +0.9

+3.4 (0.0)a +2.5 +1.1 +2.3 +2.2 +1.4 +0.9 +3.5 +2.7 +2.0 (+4.2) m +0.5 +0.7

+4.0 +1.5 +2.8 +1.5 +2.3 +2.8 +1.4 +1.3 +3.2 +2.1 +2.1 +4.1 +0.7 +1.2

+2.9 +0.9 +1.7 +1.4 +2.3 +22 +1.3 +1.0 +2.7 +1.2 +1.4 +2.1 +0.5 +0.9

+2.5 +0.7 +1.4 +0.6 +2.1 +2.1 +1.5 +1.2 +2.6 +0.8 +1.2 +2.2 +0.3 +1.4

+1.2 +1.1 +1.0 +1.2 +1.7 +2.0 +1 • +2.1 +2.7 +1.0 +1.0 +2.1 +1.6 +2.0

+1.4 +0.4 +0.5 +1.1 +1.5 +1.4 +1.8 +2.1 +2.1 +1.5 +1.9 +2.1 +2.5 +3.0

+1 2 +0.2 +0.1 +1.4 +1.0 +2.0 +2.6 +2.0 +1.6 +1.7 +1.7 +1.6 +1.7 +3.0

+1.3 +0.1 +0.4 +1.9 +1.4 +2.1 +2.8 +2.4 +2.3 +2.5 +0.8 +1.9 +0.2 +1.8

+0.1 +0.7 +1.5 +2.1 +1.8 +0.4 +2.8 +3.4 +1.1 +3.4 +0.9 +0.4 +2.0 +1.5

+0.8 (+8.4) s +0.9 +1.4 +0.7 -0.1 +2.6 +2.0 -0.7 +1.6 -0.7 -1.2 +2.1 +0.6

+1.2 (+2.3)m +0.1 +0.9 +0.8 +0.4 +3.1 +2.1 +0.8 +02 +02 (-1.5) a +1.8 0.0

-0.7 (-2.2) B -1.4 -1.7 -1.7 -0.6 -1.3 -1.4 -2.1 -3.8 -1.4 -1.7 -2.2 -1.4

1 2 3 4 5 6 7 8 9 10 11 12 13a 14 m

A euohols.

?4

~

D 86

APPENDIXES (Nonmandatory

XI. EXAMPLES

ILLUSTRATING

Information)

CALCULATIONS

correction ('F) = 0.00012 (760 - 740) (460 + ~).

T ~ o ~ ' C ) = 9 4 + [(109 - 94)(45.3 - 40)/(50 - 40)]

- lo2.o'c (xi.7)

(XI.I)

Tso~'F)

corrected loss = (0.750 x 4.7) + 0.125 = 3.6. corrected recovery

=

94.2 + (4.7 - 3.6)

=

95.3.

=

33.5 + [(40.5

-

33.5)(5.3

-

5)/(10

5)] = 33.9"C

-

Tlon('F) = 92 + [(104 - 92X5.3 - 5)/(10 - 5)] = 92.7"F

TABLE X1.1

+

[(228

-

201)(45.3

(XI.3)

Init~ Boiling Point 6 ~ recovered 10 • recovered 15 ~; recovered 20 ~t recovered 80 ~t recovered 40 ~ re(~)ver~ 50 ~t reoovemd 60 Y, reoovemd 70 ~ recovered 80 Y, reoovemd 85 Y, reoovemd 90 • recovered 95 • recovered End Point

40)/(50

-

40)]

(XI.8)

TgoE(*C) - 181.5 + [(201.0 -

(XI.4)

1 8 1 . 5 ) ( 8 5 . 3 - 8 5 ) / ( 9 0 - 85)] = 182.7"C

Tgo~('F) = 359 + [(394 - 359)(85.3 - 85)/(90 - 85)] - 361.1"F

(XI.9)

(XI.10)

X 1 . 2 . 4 Thermometer Reading at 90 % Evaporated (85.3 % Recovered) Not Corrected to 101.3 kPa Pressure (See 10.8.1): T g o ~ ( ' C ) - 180.5 + [(200.4 -

(XI.5)

1 8 0 . 5 ) ( 8 5 . 3 - 8 5 ) / ( 9 0 - 85)] -

181.7"C

TgoE('F) = 357 + [(392 - 357X85.3 - 85)/(90 - 85)] - 359.1"F

(XI.6)

Thermometer Readings Corrected to 101.3 kPa (780 mm HO) Pressure

B,ewnetrk: Pm__~__~e

-

X 1.2.3 Thermometer Reading at 90 % Evaporated (85.3 % Recovered) (See 10.8.1):

X I.2 Thermometer Readings at Prescribed Percentages Evaporated: X 1.2.1 Thermometer Reading at 10 % Evaporated (5.3 % Recovered) (see 10.8.1): Tto~'C )

201

(X 1.2)

Recovery Correction to 101.3 kPa (see 10.5.2):

Xl.I.3

-

- 215.3"F

Loss Correction to 101.3 kPa (see 10.5):

XI.1.2

OF DATA

X I . 2 . 2 Thermometer Reading at 50 % Evaporated (45.3 % Recovered) (See 10.8.1):

X I . I Thermometer Readings Corrected to 101.3 kPa (760 mm Hg) Pressure: X I . I . 1 Thermometer Readings Correction to 101.3 kPa (see 10.3): correction ('C) -- 0.0009 (101.3 - 98.6) (273 + to)

FOR REPORTING

Observed 98.6 kPa (740 mm HO) oc OF

Coffered 101.3 kPa (780 mm HO) oC OF

25.5 33.0 39.8 48.0 54.5 74.0 93.0 108.0 123.0 142.0 166.8 180.5 200.4

78 91 133 115 133 165 199 228 253 255 332 357 392

26.0 88.8 40.0 48.8 55.0 75.0 94.0 109.0 124.0 143.5 155.0 181.6 201.0

79 92 104 116 131 187 201 228 258 290 3,34 359 394

ii5.0

4i9

~)i(5

;'~i

z

54.2

.

Residue. Y,

1.1

...

1.1

...

Los,

4.7

...

3.8

...

75

983

..

(XI.II)

(Xl.12)

~1~) D 86

X2. CALCULATION OF REPEATABILITY AND REPRODUCIBILITY OF VOLUME % (RECOVERED OR EVAPORATED) AT A PRESCRIBED TEMPERATURE READING X2.1 Some specifications require the reporting of the volume % evaporated or recovered at a prescribed temperature. The statistical determination of the precision of the volume % evaporated or recovered at a prescribed temperature has not been directly measured for Groups 0 or 1 in an interlaboratory program. The following procedure makes the assumption that the precision of the volume % evaporated or recovered at a prescribed temperature is equivalent to the precision of the temperature measurement at that point divided by the rate of change of temperature versus volume % evaporated or recovered. The estimation becomes less valid at high slope values. X2.2 Calculate the rate of change in thermometer reading in degrees Celsius (or Fahrenheit) per the volume % evaporated or recovered ( ' C ( F ) / V % ) in accordance with 11.4 using temperature values which are higher and lower than the prescribed temperature in question. X2.3 Calculate the repeatability (ro) or reproducibility of temperature (Ro) or both of the temperature using the value of " C ( F ) / V % as determined in X2.2 and the appropriate table or figure as indicated in Table AI.I. X2.4 Determine the repeatab'dity or reproducibility or both of the volume % evaporated or recovered at a prescribed temperature from the following formulas: rVOI % == r J ( ' C ( F ) I V % )

'%ol % - RJ('C(F)/V%)

TABLE X2.1 DiatlllatlonPoint Recovered, mL

Temperature, °C

Temperature, °F

10 20 30 40

84 94 103 112

183 202 217 233

DletBationPoint Evaporated, mL

Temperature, °C

Temperatt~, °F

10 20 30 40

83 94 103 111

182 201 217 232

Volume (mL) Recoveredat

93.8 (200) °C (F) 18.0

voeme (rat.) Evaporated at

93.a (2oo) "c (F) 18.4

X2.5 E x a m p l e Calculation: X2.5.1 For a Group 1 sample exhibiting distillation characteristics as per Table X2.1. To determine 'vol % evaporated at 93.YC (200"F) (from 11.4.5). "C/V %, F/V % - 0.05 (T(,+,o) •C / V % , F / Y % - 0.05 (7"(,+,0) T(,-,0)) - 7"(,-,o9 "C/V% = 0.05 (Too) - TOo)) • F / v ~ - 0.05 (Too) - 1"(,=) "C/V% = 0.05 (103 - 83) " F / V % - 0.05 (217 - 182) •C l V % - 0 . 0 5 (20) "F/V% - 0.05 (35) -

(X2.1)

where: Wol %

Distillation Data From • Group 1 Sample Manual Distillation

•CIV%

= repeatability of the volume % evaporated or

= 1.0

X2.5.2 From Fig. 4 (°C) or ro - 0.864 ( ' C / V % ) + 1.214 ro - 0.864 (1.0) + 1.214 re - 2.078 X2.5.3 From X2.4: 'vol % = r J ( ' C / V %)

recovered, = reproducibility of the volume % evaporated or recovered, ro = repeatabifity of the temperature at the prescribed temperature, Ro = reproducibility of the temperature at the prescribed temperature, and " C ( F ~ I V % = rate of change in thermometer reading in degrees Celsius (Fahrenheit) per the volume % evaporated or recovered. Rvol %

"vol % = 2.078/I.0 "vol % = 2. I

•F / V % = 1.75

Fig. 5 ('F): ro - 0.864 ( ' F / V ~ ) + 2.186 r o - 0.864 (1.75) + 2.186 r e " 3.698 rVOl % = r J ( ' F / V %) "vol % = 3.698/1.75 'vol% = 2.1

The Amerioan ~ for Tutlng and Material° taku no poaltlon re~m=tlr~ the validity of any patant r l ~ aim°fred In oonnectk~ with any Item mentioned In this Mandard. U~mraof thll Itandetd are exprmmly advlHd that detocn'dtmtlon of the validlly of any auch patent rights, end the risk of Infringement of auch rights, are entirely their own relponalblllty. Thl8 atandard le subject to revlalonat any time by the ruponalble teohnlcalcommittee and must be revlewed every llveyears and Ifnot revlsed,eitherr m ~ or withdrawn. Your comments are invitedeitherfor~ of thlaalandard or foradditlonalBtandarda and eheuld be a d d ~ to A S T M Headquarter. Your comments willreceive carefuloonalderatlonat a meetlng of the re~oo~Ible teohnlcal ¢aynmittee. which you may attend. Ifyou feel that your comments have not ~ a falrhearing you should make your views known to the ASTM Comm~ee on Standard& 100 Barr Harbor Drive, West Conshehockon, PA 19428.

76

( 1 ~ ) Designation: D 87 - 87 (Reapproved 1993) (1

An AmericanNational Standard Technical Assoc~ti0t~of Pulp and PlkowIndulW Standard MethodT 630 m-61 Method 1462-FecW'alTest Method Standard No. 791b Brim Standard 4695

Designation:55•83 m t,t~m ~uM

Standard Test Method for Melting Point of Petroleum Wax (Cooling Curve) 1 This standard is issued under the fixed designation D 87; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript e~ilon (() indicates an editorial change since the last revision or reapproval. This test method was adopted as a joint ASTM-IP standard in 1966.

~' NoTE--Keywords were added editorially in October 1993.

1. Scope 1.1 This test method covers the determination of the melting point (cooling curve) of petroleum wax. It is unsuitable for waxes of the petrolatum group, microcrystalline waxes, or blends of such waxes with paraffin wax or scale wax.

4. Summary of Test Method

4.1 A specimen of molten wax in a test tube fitted with a thermometer is placed in an air bath, which in turn is surrounded by a water bath held at 16 to 28"C (60 to 80"1='). As the molten wax cools, periodic readings of its temperature are taken. When solidification of the wax occurs, the rate of temperature decreases, yielding a plateau in the cooling curve. The temperature at that point is recorded as the melting point (cooling curve) of the sample.

NOTE I - - F o r additional m e t h o d s used for testing petroleum waxes, see Test Method D 127 and Test Method D 938. Results m a y differ, depending on the m e t h o d used. For pharmaceutical petrolatum, Test M e t h o d D 127 usually is used.

5. Significance and Use

1.2 The values stated in SI units are to be regarded as the standard. The values in parentheses are for information only. 1.3 This standard does not purport to address all of the

5.1 Melting point (cooling curve) is a test that is widely used by wax suppliers and consumers, it is particularly applied to petroleum waxes that are rather highly paraffinic or crystalline in nature. A plateau occurs with specimens containing appreciable amounts of hydrocarbons that crystallize at the same temperature, giving up heat of fusion, thus temporarily retarding the cooling rate. In general, petroleum waxes with large amounts of non-normal hydrocarbons or with amorphous solid forms will not show the plateau.

safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applica. bility of regulatory limitations prior to use. 2. Referenced Documents

2. I A S T M Standard: D 127 Test Method for Drop Melting Point of Petroleum Wax, Including Petrolatum2 D 938 Test Method for Congealing Point of Petroleum Waxes, Including Petrolatum2 E 1 Specification for ASTM Thermometers3

6. Apparatus

6.1 The necessary apparatus is described in Annex A 1. 7. Test Specimen

7.1 Obtain a sample ofwax representative of the shipment to be tested. From each test unit obtain a portion of wax weighing at least 25 g for each melting point determination.

3. Definition

3.1 melting point (cooling curve) of petroleum wax-temperature at which melted petroleum wax first shows a minimum rate of temperature change when allowed to cool under prescribed conditions.

8. Procedure 8.1 Support the air bath in its proper position in the water bath. Fill the water bath to within 13 mm (I/2 in.) of the top with water at a temperature of 16 to 28"C (60 to 80"F). The bath temperature is kept within these limits throughout the test. 8.2 Heat the wax sample to at least 8"C (15"F) above its expected melting point (see Note 3). To heat the wax sample use a suitable container in an oven or water bath which is held at a temperature not exceeding 9YC (200"F). Avoid the use of direct heat such as flame or hot plate. Do not keep the sample in the molten state longer than l h. NOTE 3--If no estimate of the melting point is available, heat the wax sample to 10"C (15°F) above the temperature at which the wax is

NOTE 2--The so-called "American Melting Point" is arbitrarily 1.65"C (3°F) above the Melting Point (Cooling Curve) of Petroleum Wax.

' This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcom, mitte¢ D02.10 on Properties of Petroleum Wax. In the IP, this test method is under the jurisdiction of the Standardization Committee. Current edition approved Oct. 30, 1987. Published December 1987, Originally published as D 87 - 21 T. Last previous edition D 87 - 77 (1982). 2 Annual Book of ASTM Standards, Vol 05.01. 3 Annual Bcu)k of ASTM Standards, Vols 05.03 and 14.03.

77

~) D 87 completely molten, or to from 90 to 93"C (195 to 200"F) before proceeding to the next step. 8.3 Fill the test tube to a height of 51 mm (2 in.) with the melted sample. Insert the melting point thermometer through the center of a cork so that the 79-mm (Y/g-in.) immersion line is at the lower surface of the cork. Insert the cork into the test tube so that the bottom of the thermometer bulb is 10 mm (3/s in.) from the bottom of the test tube. Support the test tube assembly in the air bath as shown in Fig. 1 while the temperature of the molten wax is still at least 8°C (15°F) above its expected melting point (Note 3). 8.4 Read the melting point thermometer every 15 s. Record each reading to the nearest estimated 0.05"C (0.1 °F). Observe the progress of these sequential readings to determine the appearance of the plateau. Identify the plateau as the first five consecutive readings all of which agree within 0. I°C (0.2°F). Discontinue the test after obtaining these five plateau readings. NOTE 4mlf no plateau appears as defined above, the reading procedure is continued until either (1) the temperature reached 38"C (100"F) or (2) the temperature reaches a point 8"{=(15"F) below a temperature where the wax has solidified(as may be observed through a transparent bath). In either of these cases the test is discontinuedand the method is judged Not Applicable to the sample (see Note I for other methods).

9. Calculation and Report 9.1 Average the first five consecutive thermometer readings of the identified plateau, which agree within 0.1"C (0.2°F). Correct this average for error in the thermometer scale where necessary. 9.2 Report the result to the nearest 0.05°C (0. l'F) as the Petroleum Wax Melting Point (Cooling Curve), Test Method D 87.

10. Precision and Bias 10.1 Precision--The precision of this test method as determined by statistical examination of inteflaboratory results is as follows: NOTE 5--This method is considered suitable for waxes of melting point between 38"C(100"F) and 82"C(180"F). The precisiondata below were obtained in interlaboratorystudiesby ASTM CommitteeD-2 using waxes in 127 to 144"F range and by IP using waxes in 108 to 151"F range. 10.1.1 Repeatability--Tbe difference between two test results, obtained by the same operator with the same apparatus under constant operating conditions on identical test material, would in the long run, in the normal and correct operation of the test method, exceed the following values only in one case in twenty: 0. I'C (I.0"F) 10.1.2 Reproducibility---The difference between two single and independent results obtained by different operators working in different laboratories on identical test material would, in the long run, in the normal and correct operation of the test method, exceed the following values only in one case in twenty: 0.5"C ( 1.0"1=) 10.2 These precision values have been obtained by statistical examination of interlaboratory test results and were first published in 1965. These values are based on a study among 15 laboratories, using five paraffin waxes with a melting point range of 53 to 66°C (128 to 151°F). 10.3 Bias--The procedure in this test method for has no bias because the value of melting point can be defined only in terms of a test method. 11. Keywords 11.1 cooling curve; melting point; petroleum wax; wax

78

~

D 87

ANNEX

(Mandatory Information) A1. APPARATUS in.) above the bottom, and a reference line for positioning of the bottom oftbe thermometer at 10 mm (3/s in.) above the bottom. AI.2 Air Bath--A cylinder 51 mm (2 in.) in inside diameter and 114 mm (4'/2 in.) in depth. Provide the air bath with a tightly fitting cork having a central opening for holding the test tube firmly in a vertical position in the center of the air bath. A1.3 Water Bath--A suitable cylindrical vessel, 130 mm (51/s in.) in inside diameter and 152 mm (6 in.) in depth. Provide a fitted cover equipped to support the air bath vertically so that the sides and bottom of the air bath are surrounded by a layer of water 38 mm (1'/2 in.) thick. Provide the cover with an opening through which the bath thermometer may be suspended 19 mm (3/4in.) from the outside wall of the water bath.

AI. 1 Test Tube--A standard glass test tube, 25 mm (1 in.) in outside diameter, and 100 mm (4 in.) in length. It may be marked with a reference line for sample filling at 51 mm (2

i ;nLLINL~INE "-'l-

NOT~ A l . l - - T h e air bath, water bath, and water bath cover may be

made in one assemblyas shown in Fig. AI.I. AI.4 Melting Point Thermometer--A Wax Melting Point Thermometer having the range shown below and conforming to the requirements as prescribed in Specification E 1 or in the specifications for IP thermometers: Thermometer Number

L

(Sll

Temperature Range

ASTM

lP

38 to 82"C 100 to 180"F

14C 14F

17C 17F

A 1.5 Bath Thermometer--Any suitable partial immersion thermometer, accurate to 1.0"C (2"F) throughout the required range. AI.6 Timer--Interval timer or stop watch.

NoTE--Dimensionsin inches(milUmetres). FIG. A1.1 Apparatus for Determination of Melting Point (Cooling Curve) of Petroleum Wax

The American Society for Tasting and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technicet committee and must be reviewed every five years and if not revised, either raspproved or withdrawn. YOurcomments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. YOurcomments will receive careful consideration at a meeting of the responsible technical committee, which you may attend, if you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103.

79

(]~l~ Designation: D 96-88 (Reapproved 1994)~1 ~ I)

An American National Standard Bntish Standard 4385 American Association State Htghway Transportation Standard AASHTO No. 3"55

Designation: MPMS Chapter 10.4

Standard Test Method for Water and Sediment in Crude Oil by Centrifuge Method (Field Procedure) 1 This standard is issued under the fixed designation D 96; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript cpsilon (~) indicates an editorial change since the last revision or re.approval.

This method has been approved by the sponsoring committees and accepted by the Cooperating Societies in accordance with established procedttres. This test method has been adopted for use by government agencies to replace Method 3003 of Federal Test Method Standard No. 791b. Annex A 1 is under revision and will be included in subsequent revisions to this standard. o NOTE--Section 11 was added editorially in May 1994.

D 3699 Specification for Kerosine4 D 4006 Test Method for Water in Crude Oil by Distillation 4 D 4057 Practice for Manual Sampling of Petroleum and Petroleum Products 4 D4177 Practice for Automatic Sampling of Petroleum and Petroleum Products 4 D4377 Test Method for Water in Crude Oils by Potentiometric Karl Fischer Titration 4 E 1 Specification for ASTM Thermometers 5 E 542 Practice for Calibration of Volumetric Ware 6 2.2 AP1 Standards: 7

1. Scope 1.1 This test method covers the centrifuge method for determining sediment and water in crude oil during field custody transfers. This test method may not always provide the most accurate results, but it is considered the most practical method for field determination of sediment and water. When a higher degree of accuracy is required, the laboratory procedure described in Test Methods D 4006, D 4377 or D 473 should be used. NOTE l - - W a t e r by distillation a n d sediment by extraction are considered the most accurate m e t h o d s o f d e t e r m i n i n g sediment and water in crude oils. As such, these m e t h o d s s h o u l d be employed to resolve differences in results from variations o f this procedure or between this procedure a n d other methods, or in the case o f a dispute between parties.

Manual of Petroleum Measurement Standards Chapter 8, Sampling Petroleum and Petroleum Products Chapter 10, Sediment and Water

1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

3. Summaryof Test Method 3.1 Known volumes of crude oil and solvent (water saturated if required) are placed in a centrifuge tube and heated to 60"C + 3"C (140*F _+ 5*F). After centrifugation, the volume of the sediment-and-water layer at the bottom of the tube is read. NOTE 2--It has been observed that for some waxy crude oils, temperatures of 71"C(160°F) or higher may be required to melt the wax crystals completely so that they are not measured as sediment. If temperatures higher than 60"(2 (140"1=.) are necessary to eliminate this problem, they may be used with the consent of the parties involved. If water saturation of the solvent is required, it must be done at the same temperature.

2. ReferencedDocuments 2. I A S T M Standards: D 235 Specification for Mineral Spirits (Petroleum Spirits) (Hydrocarbon Drycleaning Spirits)2 D 362 Specification for Industrial Grade Toluene 2 D 473 Test Method for Sediment in Crude Oils and Fuel Oils by the Extraction Method 3 D 846 Specification for Ten-Degree Xylene 2 D 1209 Test Method for Color of Clear Liquids (PlatinumCobalt Scale)2

4. Significanceand Use 4.1 A determination of sediment and water content is required to determine accurately the net volumes of crude oil involved in sales, taxation, exchanges, inventories, and

This test method is under the jurisdiction of Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.02.OB on Sediment and Water (Joint ASTMdP). Current edition approved March 25, 1988. Published December 1988. Originally published as D 96 - 63T. Last previous edition D 96 - 73 (1984). ~l 2 Annual Book of ASTM Standards, Vol 06.04. 3 Annual B¢~)k of ASTM Standards, Vol 05.01.

4 Annual Book of ASTM Standards, Vol 05.02. Annual Book of ASTM Standards, Vol 14.03. 6 Annual Book of ASTM Standards, Vol 14.02. 7Available from American Petroleum Institute, 1220 L St., Northwest, Washington, DC 20005.

80

q~ D 96 TABLE 1 Rotation Speeds Necessary to Produce a Relative Centrifugal Force of 500 for Centrifuges of Various Diameters of Swing Diameter of SwingA Millimeters Inches 305 330 356 381 406 432 457 483 508 533 559 584 610

12 13 14 15 16 17 18 19 20 21 22 23 24

TABLE 2 Minimum Graduation Requirements and Maximum Calibration Tolerances for 203-ram (8-in.) Cone-Shaped Tubes

Rotation Speed (r/min) 1710 1640 1580 1530 1480 1440 1400 1360 1325 1290 1260 1240 1210

Range, mL

Subdivision, mL

Volume Tolerance. mL

0-0.1 >0.1-0.3 >0,3--0,5 >0.5-1.0 >1.0-2.0 >2.0-3.0 >3.0-5.0 >5.0-10 >1 0-25 >25-100

0.05 0.05 0.05 0.10 0.10 0.20 0.5 1 5 25

+0.02 +0.03 +0.05 ¢0.05 +0.10 ±0.10 ¢0.20 ¢-0.50 +1.00 ± 1.00

TABLE 3 Minimum Graduation Requirements and Maximum Calibration Tolerancea for 167-mm (6-in.) Cone-Shaped Tubes

A Measured between the tips of the opposite tubes when lhe tubes are in

rotat~ posroon.

Range, mL

Subdivision, mL

>O-0.1 >0.1-0.3 >0.3-0.5 >0.5-1.0 >1,0-1.5 >1.5-2.0 >2.0-3.0 >3.0-5.0 >5.0-10 >10-25 >25-103

custody transfers. An excessive amount of sediment and water in crude oil is significant because it can cause corrosion of equipment and problems in processing and transporting and may violate federal, state, or municipal regulations. 5. Apparatus

5.1 Centrifuge--A centrifuge shall be capable of spinning two or more centrifuge tubes at a speed that can be controlled to give a minimum relative centrifugal force of 500 at the tip of the tubes. The rotation speed necessary to produce a relative centrifugal force of 500 for various diameters of swing can be determined from Table 1 or from one of the following equations: r/min ffi 1335 J - ~ (l) r/rain ffi 265 v r ~ (2) where: rgm = rotation speed, in revolutions per minute. rcf = relative centrifugal force, d = diameter of swing, in mm (Eel 1) or in. (Eq 2), measured between the tips of opposite tubes when the tubes are in their rotating position. The revolving head, trunnion rings, and trunnion cups, including the cushions, shall be constructed to withstand the maximum centrifugal force capable of being delivered by the power source. The trunnion cups and cushions shall firmly support the tubes when the centrifuge is in motion. The centrifuge shall be enclosed by a metal shield or case strong enough to contain flying debris in the event a tube breaks or the centrifuge malfunctions. 5.1.1 The centrifuge shall be heated and shall be capable of maintaining the sample at a temperature of 60°C +_ 3°C (140°F _+ 5°F). The minimum allowable temperature in the field shall be 52"C (125°F). 5.2 Centrifuge Tubes: 5.2.1 Centrifuge tubes shall be cone shaped and 203 mm (8 in.) or 167 mm (6 in.) in length. Tubes shall conform to the dimensions given in Fig. I (203 ram) or Fig. 2 (167 mm) and shall be made of thoroughly annealed glass. A 200-part tube shall conform to the dimensions shown in Fig. 2, with the marking for each division multiplied by 2 (for example, 25 mL = 50 parts). The mouth of each tube shall be constricted for closure with a stopper. Graduations for the

0.05 0.05 0.05 0.10 0.10 0.10 0.20 0.50 1 5 ~

Volume Tolerance, mL +0.02 +0.03 +0.05 +0.07 ¢0.10 +0.20 :L-0.30 ±0.50 +0.75 +1.0 +1.5

A Graduations at 50 anti 100.

203-mm (8-in.) and 167-mm (6-in.) tubes shall be in accordance with the requirements of Tables 2 and 3, respectively. The scale errors for a centrifuge tube shall not exceed the tolerances specified in Tables 2 and 3. The graduation requirements and scale-error tolerances shown in Tables 2 and 3 apply to calibrations made by reading the bottom of the shaded meniscus of air-free water at a temperature of 20"C (68"F). The graduations on each tube shall be clearly numbered as shown in Figs. I and 2. 5.2.2 The tube graduation marks' accuracy shall be volumetrically verified or gravimetrically certified before field use of the tube, in accordance with Practice E 542 using National Institute of Standards and Technology-traceable equipment. The verification or certification shall include a calibration check at each mark up through the 0.5-mL (l-part) mark; at the 1-, 1.5-, and 2-mL (2-, 3-, and 4-part) marks: and at the 50- and 100.mL (100- and 200-part) marks. The tube shall not be used ff the scale error at any mark exceeds the applicable tolerance from Table 2 or 3. 5.3 Preheater--The preheater shall be either a metal block or a liquid bath of sufficient depth to permit immersion of the centrifuge tube in the vertical position to the 100-mL litre (200.part) mark and capable of heating the sample to 60"C + 3"C (140°F + 5°F). 5.4 Thermometer shall have graduations at intervals of I°C (2"F) or less and shall be accurate to + I'C (+2"F). A thermometer such as ASTM IC or IF is suitable as shown in Specification E 1. 6. Reagents

6.1 The reagents listed in this section are satisfactory for use in field testing. 6.2 Demulsifier--When necessary, a demulsifier should 81

~ D 96 t

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Cone-Shaped Centrifuge Tube, 167 mm (6 in.)

saturated with water, since the solubility of water in these solvents is not significant at 60°C (140°F). NOTe 3: Warning--Kerosine is combustible(See Annex AI.I). 6.4 Stoddard Solvent (Specification D 235): 6.4.1 The typical characteristics of Stoddard solvent are a distillation range of 149-208"C (300--407"F), a minimum flash point of 38"C (100*F), and aromatics plus olefins content of less than 20 % by volume.

INSIDE TAPER SHAPE FIG. 1 Cone-Shaped Centrifuge Tube, 203 mm (8 in.)

be used to promote the separation of water from the sample, to prevent water from the sample, clinging to the walls of the centrifuge tube, and to enhance the distinctiveness of the water-oil interface. In some eases a demulsifier is required to attain agreement with the base method (see Note 1). When a demulsifier is used, it should be mixed according to the manufacturer's recommendations and should never add to the volume of sediment and water determined. The demulsifier should always be used in the form of a demulsifier-solvent stock solution or be premixed with the solvent to be used in the test. 6.3 Kerosine (Specification D 3699) 6.3.1 The typical characteristics of kerosine are a distillation range of 205-300"C (401-572"F), a maximum freezing point of -30"C (-22"F), and a minimum flash point of 38"C (100"F). 6.3.2 Stoddard solvent and kerosine do not have to be

NOTI~ 4: Warning--Stoddard solvent is combustible (See Annex

AI.2). 6.4.2 See 6.3.2. 6.5 Toluene (Specification D 362): 6.5.1 The typical characteristics of toluene are a molecular weight of 92, an American Public Health Association (APHA) color of 10 (per D 1209), a boiling range (initial to dry point) of 2.0"C (3.6"F) [recorded boiling point of I 10.6"C (231.1"F)], and 0.001% residue after evaporation. Toluene passes the American Chemical Society (ACS) test for substances darkened by H2SO4. NOTE 5: Warning--Toluene is flammable (See Annex A1.3).

6.5.2 Toluene and xylene shall be saturated with water at 60*C + 3"C (140°F + 5*F) and maintained at this tempera82

~ D 96 ture until used. A procedure for the saturation of solvents is given in the appendix. The water-saturated solvent shall be free from suspended water at the time of use. Toluene and xylene are recommended for sediment-and-water determinations involving asphaltenic crude oils. 6.6 Xylene (Specification D 846): 6.6.1 The typical characteristics of xylene are a molecular weight of 106, an APHA color of not more than 10 (in accordance with Test Method D 1209), a boiling range of 137 to 144"C (279 to 291"F), and 0.002 % residue after evaporation. Xylene passes the ACS test for substances darkened by sulfuric acid. NOTE 6: Warning--Xylene is flammable (See Annex AI.4).

6.6.2 See 6.5.2. 7. Sampling 7. I Sampling is defined as all steps required to obtain a representative quantity of the contents of any pipeline, tank, or other system and to place it in an appropriate centrifuge tube. 7.2 The sample shall be thoroughly representative of the crude oil in question, and the portion of the sample used for the sediment and water determination shall be thoroughly representative of the sample itself. If an automatic custody transfer (LACT) unit is involved, vigorous agitation of the sample container is required before the sample is transferred to the centrifuge tube or tubes. Only representative samples obtained as specified in Practices D 4057 or D 4177 shall be used for this test method. 8. Procedure 8.1 Fill each of two centrifuge tubes to exactly the 50-mL (100-part) mark with a sample taken directly from the sampling device (for example, a thief bottle, beaker, or LACT sample container) or the container in which the sample was collected. Then fill each tube with solvent to exactly the 100-mL (200-part) mark. Read the top of the meniscus at both the 50- and 100-mL (100- and 200-part) marks. If experience indicates that a demulsifier is required and one has not already been added to the solvent, add to each tube quantity of demulsifier-solvent stock solution that has previously been determined to be satisfactory for the crude oil under test. Stopper each tube tightly and invert the tubes a minimum of l0 times to ensure that the oil and solvent are uniformly mixed.

8.4 Place the tubes in the trunnion cups on opposite sides of the centrifuge to establish a balanced condition. Retighten the stoppers and spin for at least 5 minutes at a minimum relative centrifugal force of 500. 8.5 Immediately after the centrifuge comes to rest, verify the temperature. Do not disturb the oil-water interface with the thermometer. The test is invalid if the final temperature after centrifugation is below 52"C (125"F). NOTE 8mlf the final temperature is found to be below 52°C (125"F), adjust the centrifuge heater to increase the final test temperature and reinitiate the procedure, beginning with 8.2.

8.5.1 Read and record the combined volume of sediment and water at the bottom of each tube as indicated in Table 4 and Fig. 3 (Table 5 and Fig. 4 for 200-part tubes). Reheat both tubes to 60"C ± 3"C (140*F ___ 5*F), return the tubes without agitation to the centrifuge, and spin for another 5 rain at the same rate. Repeat this operation until two consecutive consistent readings are obtained on each tube. 8.6 For the test to be considered valid, a clear interface must be observed between the oil layer and the separated water. No identifiable layering (that is, an emulsion) should be present immediately above the oil-water interface. In such cases, one or more of the following remedies may be effective: 8.6. I Shake the mixture between whirlings in the centrifuge just enough to disperse the emulsion. 8.6.2 Use a different or an increased amount of demulsifier. (The demulsifier should not, however, contribute to the volume of sediment and water.) 8.6.3 Use a different or an increased amount of solvent. After a satisfactory procedure for a particular type of oil has been worked out, it will ordinarily be suitable for all samples of the same crude oil. 9. Calculation and Report 9. I Compare the readings of the two tubes. If the difference between the two readings is greater than one subdivision on the centrifuge tube (see Table 2 or 3) or 0.025 mL (0.05 % for 200-part tubes) for readings of 0.10 mL (0.20 % for 200-part tubes) and below, the readings arc inadmissible and the determination shall be repeated. 9.2 If tubes graduated in 100 mL have been used for the determination, record the sum of the final volumes of sediment and water in each tube obtained, as specified in Section 8, and report this sum as the percentage of sediment and water (see Fig. 3 for reading and reporting sediment and water when using 100-mL cone-shaped centrifuge tubes). Report the results as shown in Table 6. 9.3 If direct-reading 200-part tubes have been used for the determination, the percentage of sediment and water is the average, to three decimal places, of the values read directly from the two tubes. The percentage can only be read directly from a 200-part tube if the tube contains 50 mL or 100 parts of oil.

NOTE 7: Caution--In general, the vapor pressures of hydrocarbons at 60"C (140°F) are approximately double those at 40"C (104°F). Consequently, tubes should always be inverted at a position below eye level.

8.1.1 Where the crude oil is very viscous and mixing of the solvent with the oil is difficult, the solvent may be added to the centrifuge tube prior to the oil to facilitate mixing. In this case, extreme care must be taken to fill the centrifuge tube to exactly the 50-mL (100-part) mark with solvent and then to exactly the 100-mL (200-part) mark with the sample. 8.2 Loosen the stoppers to prevent pressure buildup during heating and immerse the tubes to the 100-mL (200-part) mark in a preheater. Heat the contents to 60"C __. 3"C (140*F ± 5*F). 8.3 Secure the stoppers and again invert the tubes 10 times to ensure uniform mixing of the oil and solvent.

TABLE 4

Procedure for Reading a 100-mL Cone-Shaped Tube

Volume of Sedimentand Water, mL 0.0-0.2 0.2-1.0 >1.0

83

Read to Nearest, mL

0.025 0.05 0.10

D 96 TABLE 5

TABLE 6

Procedure for Reading a 200-Part Cone-Shaped Tube

Volume of Sediment and Water, ~0

Read to Nearest, %

0.O-0.4 0.4-2.0 >2.0

0.05 0.10 0.20

Expression of Results

Volume of Sedimentand Water, mL

9.4 If the volume of oil is greater or less than 50 mL, or 100 parts, calculate the percentage of sediment and water as follows: Sediment and water, percent = (S/V) x 100 where: S -- volume of sediment and water, mL or parts and V = volume of oil tested, mL or parts. For example, if the total volume of oil tested (V) is 20 mL and the volume of sediment and water (S) is 0.15 mL: Sediment and water, % = (0.15/20) x 100 = 0.75 9.5 If the test conditions outlined in Section 6 are not followed exactly, the following must also be reported: 9.5.1 The solvent used and the water saturation temperature. 9.5.2 The type and amount of demulsifier (if used). 9.5.3 The temperatures of the sample and solvent, the

Tube I

Tube 2

None visible None visible 0.025 0.025 0.05 0.05 0.075 0.075 0.10 0.10

Trace 0.025 0.025 0.05 0.05 0.075 0.075 0.10 0.10 0.15

Total Sediment and Water, % 0 0.025 0.5 0.075 0.10 0.125 0.15 0.175 0.20 0.25

preheater temperature, the centrifuge temperature, and the temperature of the final mixture after centrifuging. 9.5.4. The number of samples or tubes used in the determination. 10. Precision and Bias 10.1 Precision--The precision of this test method is being determined.

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Procedure for Reading Sediment and Water When Using a Tube Reading in 100 mL

FIG. 4

84

Procedure for Reading Sediment and Water When Using a Tube Reading in 200 Parts

~

D 96

10.2 BiasmSince there is no accepted reference material suitable for determining the bias, no statement about bias is being made.

11. Keywords 11.1 centrifuge; centrifuge tube; crude oil; field procedure; sampling; sediment and water; solvent

ANNEX

(Mandatory Information) A1. Precautionary Statements AI.I Kerosine--Keep away from heat, sparks, or open flame. Keep container closed when not in use. Kerosine's vapor is harmful. Provide adequate ventilation when kerosine is used. Neither an Occupational Safety and Health Administration permissible exposure limit nor an American Conference of Governmental Industrial Hygienists threshold limit value has been established for kerosine. Ingestion of kerosine may cause irritation of the digestive tract; ingestion of large amounts may cause signs of central nervous system depression. Aspiration of this material into the nervous system depression. Repetitive applications of kerosine directly to the skin of laboratory animals over their lifetimes has resulted in skin cancer in the animals. Petroleum hydrocarbons of similar composition and boiling range have been shown to produce kindey damage and tumors in laboratory animals. Avoid skin contact with kerosine. Prolonged or repeated skin contact may cause defatting and drying of the skin. A I.2 Stoddard Solvent--Keep away from heat, sparks, or open flame. Its container should be kept closed when not in use. The solvent's vapor is harmful. Adequate ventilation should be provided when the solvent is used, and airborne concentrations should be kept below the established exposure limits. The permissible exposure limit established by the Occupational Safety and Health Administration for Stoddard solvent is 500 parts/million.The American Conference of Governmental IndustrialHygienists has establisheda threshold limit value of I00 parts per million. Inhalation of vapors or spray mist should be avoided. Acute overexposure may result in irritation of the throat and lungs. High concentrations may cause central nervous system depression. Aspiration of thismaterial into the lungs may cause chemical pneumonia. Long-term exposure can cause chronic health effects.Chronic overexposure has resulted in liver,heart, and blood disorders. Intense and protracted exposure to the solvent may be associated with an increased risk of kidney cancer, kidney disease, and nerve and brain damage. Avoid skin contact with the solvent. Prolonged or repeated contact with the liquid can resultin drying and defatting of the skin that may result in irritationand dermatitis. AI.3 Toluene--Keep away from heat, sparks, or open

flame. Keep container closed when not in use. Toluene's vapor is harmful. Provide adequate ventilation when toluene is used, and airborne concentrations should be kept below the established exposure limits. The Occupational Safety and Health Administrator has established a permissible exposure limit of 200 parts/million, with an acceptable ceiling of 300 parts/million and an acceptable maximum peak of 500 parts/million for 10 min. The American Conference of Governmental Industrial Hygienists has established a threshold limit value of 100 parts/million, with a short-term exposure limit of 150 parts/million for 1 min. Prolonged overexposure through inhalation may cause coughing, shortness of breath, dizziness and intoxication. Aspiration of this material into the lungs may cause chemical pneumonia. Long-term exposure to this material may cause chronic health effects. Toluene may remove fats from the skin and cause chronic dermatitis. Other potential hazards include possible liver, kidney, and nervous system damage and cardiac sensitization to epinephrine. In addition, toluene has been shown to be toxic to the embryo and fetus at high concentrations in animal experiments, however, such studies have failed to demonstrate frank birth defects. Prolonged or repeated skin contact may cause skin to become dry or cracked. AI.4 Xylene--Keep away from heat, sparks, or open flame. Keep container closed when not in use. Xylene's vapor is harmful. Provide adequate ventilation when xylene is used, and keep airborne concentrations below established exposure limits. The Occupational Safety and Health Administration's permissible exposure limit for xylene is 100 parts/million. The American Conference of Governmental Industrial Hygienists has established a threshold limit value of 100 parts/million with a 15-min short-term exposure limit of 150 parts/million. Overexposure through inhalation may cause shortness of breath, dizziness, intoxication, and collapse. Aspiration of this material into the lungs may cause chemical pneumonia. Long-term exposure to this material can cause chronic health effects. Prolonged, repeated exposure to high levels of xylene can induce central nervous system problems and may cause liver and kidney damage. Avoid prolonged or repeated skin contact with xylene. Skin contact may result in delayed skin irritation and blistering.

85

~) D 96

APPENDIX

(NonmandatoryInformation) X1. DEMUI.~IFIERS AND WATER SATURATION OF SOLVENTS XI. I Water Saturation of Solvents: X I.I.I Fill each of two centrifuge tubes to the 2-mL (4-part) mark with water and then to the 100-mL (200-part) mark with the solvent to be saturated. X I. 1.2 Stopper the tubes and shake vigorously for 30 s, holding the tubes below eye level, to disperse the water in the solvent. Loosen the stoppers. X1.1.3 Place the tubes containing the water/solvent mixture into a sample preheater or heated (nonspinning) centrifuge maintained at a temperature of 60"C (140*F) for a minimum of 30 min. Xl.l.4 Inspect the water/solvent mixture for suspended water droplets before use. If any suspended water is visible, the tubes must be centrifuged at a temperature of 60"C (140*F) for 5 rain at a speed sufficient to give a relative centrifugal force of 500 at the tube tip. X1.1.5 Use the top 50 mL (100 parts) of the mixture from each tube for test purposes. Take particular care not to pour any of the free water in the tip of each tube into the sample. X 1.2 Demulsifiers: X 1.2.1 Although a good commercial crude-oil demulsifier will work effectively with a wide range of crude oils, there are

some etudes for which one demulsifier is more effective than another. If the selected demulsifier does not provide the desired results, others should be tried. XI.2.20vertreatment with a demulsifier can add erroneously to the apparent sediment and water level. Demulsifiers do not in general contain water, but they do have a limited solubility in the solvent-sample and, if added in excessive quantities, can show up after centrifuging as a separate immiscible component at the bottom of the tube. To prevent this problem, the demulsifier should always be used in the form of a demulsifier-solvent stock solution or should be premixed with the solvent to be used in the test. In either case, the quantity of demulsifier to be added to the solvent should be based on tests for the particular demulsifier solvent combination. The demulsifier manufacturer's instructions should be followed when a demulsifier solution is prepared. X1.3 Demuisiliers and demulsifier-solvent solutions should always be stored in accordance with the manufacturer's recommendations. Each container used to store a demulsifier or demulsifier-solvent solution should be dated, and the contents should be discarded when they reach the demulsifier manufacturer's recommended shelf life.

The American Society for Testing and Materials takes no postt~on respecting the vahdity of any patent rights asserted in connection with any/tern mentioned in this standard. Users of this standard are expressly advised that determination of the vahdlty of any such patent rights, and the risk of mfringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every hve years and ff not revised, either reapproved or withdrawn Your comments are tnwted either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, whtch you may attend, if you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 100 Barr Harbor Drive, West Conshohocken, PA 19428,

86

q~)

Designation: D 97 - 96a

IPW Designation: 15/95 rHt I~lTur~

Standard Test Method for Pour Point of Petroleum Products I This standard is issued under the fixed desit~mtion D 97; the number immediately following the d ~ a f i o n indicates the year of originaladoption or, in the case of revision,the year of lustrevision.A number in parenthesesindicatesthe year oflastreapproval.A superscript cpsilon (d indicates an editorialchan~ since the last rcvi~on or rcapproval.

This testmethod has been adopted for use by government agencies to replaceMethod 201 of Federal Test Method Standard No. 791b, and Method 4452 of Federal Test Method Standard No. 141.4. This test method was adopted as a joint ASTM-IP Standard in 1965.

1. Scope 1.1 This test method is intended for use on any petroleum product, a A procedure suitable for black specimens, cylinder stock, and nondistillate fuel oil is described in 7.8. A procedure for testing the fluidity of a residual fuel oil at a specified temperature is described in the appendix. 1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements, see Section 6.

3. Terminology 3.1 Definitions: 3.1.1 black oil, n--lubricant containing asphaltic materials. Black oils are used in heavy-duty equipment applications, such as mining and quarrying, where extra adhesiveness is desircxi. 3.1.2 cylinder stock, n--lubricant for independently lubricated engine cylinders, such as those of steam engines and air compressors. Cylinder stock are also used for lubrication of valves and other elements in the cylinder area. 3.1.3 residual fuel, n--a liquid fuel containing bottoms remaining from crude distillation or thermal cracking; sometimes referred to as heavy fuel oil. 3.1.3.1 Discussion--Residual fuels comprise Grades 4, 5, and 6 fuel oils, as defined in Speofication D 396.

2. Referenced Documents 2.1 A S T M Standards: D 117 Guide to Test Methods and Specifications for Electrical Insulating Oils of Petroleum Origin 4 D 396 Specification for Fuel Oils5 D 1659 Test Method for Maximum Fluidity Temperature of Residual Fuel Oil6 D 2500 Test Method for Cloud Point of Petroleum Oils5 D 3245 Test Method for Pumpability of Industrial Fuel Oils7 E 1 Specification for ASTM Thermometers 8 E 77 Test Method for Inspection and Verification of Thermometers 8 2.2 IP Standards: Specifications for IP Standard Thermometers 9

4. Summary of Test Method 4.1 After preliminary heating, the sample is cooled at a specified rate and examined at intervals of 3°C for flow characteristics. The lowest temperature at which movement of the specimen is observed is recorded as the pour point. 5. Significance and Use 5.1 The pour point of a petroleum specimen is an index of the lowest temperature of its utility for certain applications. 6. Apparatus 6.1 Test Jar, cylindrical, of clear glass, fiat bottom, 33.2 to 34.8-mm outside diameter, and 115 to 125 mm in height. The inside diameter of the jar can range from 30.0 to 32.4 ram, within the constraint that the wall thickness be no greater than 1.6 ram. The jar shall have a line to indicate a sample height 54 _+ 3 mm above the inside bottom. 6.2 Thermometers, having the following ranges and conforming to the requirements prescribed in Specification E l for thermometers:

This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.07 on Flow Properties. Current edition approved Nov. 10, 1996. Published January 1997. Originally published as D 97 - 27. In 1927, revised and repl_~ed__former D 47. Last previous edition D 97 - 96. In the IP, this test method is under the jurisdiction of the Standardization Committee. 2 The cloud point procedure formerly part of thistestmethod now ~ as Test Method D 2500. 3 Statements defining this test and its .significance when appfied to electrical insulating oils of mineral origin will be found in Guide D 117. 4 Annual Book of A S T M Standards, Vol 10.03. s Annual Book of A S T M Standards, Vol 05.01. 6 Discontinued; see 1984 Annual Book of A S T M Standards, Voi 05.01. 7 Annual Book of ASTM Standards, Vol 05.02 a Annual Book of A S T M Standards, Vol 14.03. 9 Methods for Analysis and Testing, IP Standards for Petroleum and its Products, Part 1, Vol 2.

Thermometer High cloud and pour Low cloud and pour Melting point

Temperature Range -38 to + 50"C -80 to +20"C +32 to + 127"C

Theilnometer Number ASTM IP 5C 6C 6 IC

IC 2C 63C

6.2.1 Since separation of liquid column thermometers occasionally occurs and may escape detection, thermometers should be checked immediately prior to the test and used 87

~) D 97 only if they prove accurate within _I°C (for example ice point). 6.3 Cork, to fit the test jar, bored centrally for the test thermometer. 6.4 Jacket, watertight, cylindrical, metal, flat-bottomed, 115 + 3-mm depth, with inside diameter of 44.2 to 45.8 mm. It shall be supported in a vertical position in the cooling bath (see 5.7) so that not more than 25 mm projects out of the cooling medium, and shall be capable of being cleaned. 6.5 Disk, cork or felt, 6 mm thick to fit loosely inside the jacket. 6.6 Gasket, to fit snugly around the outside of the test jar and loosely inside the jacket. The gasket may be made of rubber, leather, or other material that is elastic enough to cling to the test jar and hard enough to hold its shape. Its purpose is to prevent the test jar from touching the jacket. 6.7 Bath or Baths, maintained at prescribed temperatures with a firm support to hold the jacket vertical. The required bath temperatures may be obtained by refrigeration if available, otherwise by suitable freezing mixtures. Freezing mixtures commonly used for temperatures down to those shown are as follows:

NOTE 7 - - I t is known that some materials, when heated to a temperature higher than 45"C during the preceding 24 h, do not yield the same pour point results as when they are kept at room temperature for 24 h prior to testing. Examples of materials which are known to show sensitivity to thermal history are residual fuels, black oils, and cylinder stocks.

8. l. l Samples of residual fuels, black oils, and cylinder stocks which have been heated to a temperature higher than 45"C during the preceding 24 h, or when the thermal history of these sample types is not known, shall be kept at room temperature for 24 h before testing. Samples which are known by the operator not to be sensitive to thermal history need not be kept at room temperature for 24 h before testing. 8.1.2 Experimental evidence supporting elimination of the 24-h waiting period for some sample types is contained in a research report, t0 8.2 Close the test jar with the cork carrying the high-pour thermometer (5.2). In the case of pour points above 36"C, use a higher range thermometer such as IP 3C or ASTM 61C. Adjust the position of the cork and thermometer so the cork fits tightly, the thermometer and the jar are coaxial, and the thermometer bulb is immersed so the beginning of the capillary is 3 mm below the surface of the specimen. 8.3 For the measurement of pour point, subject the specimen in the test jar to the following preliminary treatment: 8.3.1 Specimens Having Pour Points Above -33"C--Heat the specimen without stirring to 9"C above the expected pour point, but to at least 45"C, in a bath maintained at 12°C above the expected pour point, but at least 48°C. Transfer the test jar to a water bath maintained at 24°C and commence observations for pour point. 8.3.2 Specimens Having Pour Points of-33=C and Below-Heat the specimen without stirring to 45°C in a bath maintained at 48"(2 and cool to 150C in a water bath maintained at 6*C. Remove the high cloud and pour thermometer, and place the low cloud and pour thermometer in position. 8.4 See that the disk, gasket, and the inside of the jacket are clean and dry. Place the disk in the bottom of the jacket. Place the gasket around the test jar, 25 mm from the bottom. Insert the test jar in the jacket. Never place a jar directly into the cooling medium. 8.5 After the specimen has cooled to allow the formation of paraffin wax crystals, take great care not to disturb the mass of specimen nor permit the thermometer to shift in the specimen; any disturbance of the spongy network of wax crystals will lead to low and erroneous results. 8.6 Pour points are expressed in integers that are positive or negative multiples of 30C. Begin to examine the appearance of the specimen when the temperature of the specimen is 9"C above the expected pour point (estimated as a multiple of 3=C). At each test thermometer reading that is a multiple of 30C below the starting temperature remove the test jar from the jacket. To remove condensed moisture that limits visibility wipe the surface with a clean cloth moistened in alcohol (ethanol or methanol). Tilt the jar just enough to ascertain whether there is a movement of the specimen in the test jar. The complete operation of removal, wiping, and

For Temperatures Down Ice and water

Crushed ice and sodium chloride Crushed ice and calcium chloride crystals Acetone or petroleum naphtha (see Section 6) chilled in a covered metal beaker with an ice-salt mixture to -12°C then with enough solid carbon dioxide to give the desired temperature.

9"C -12"C -27"(2 -57"(2

NOTE l - - T h e r e are automatic pour point testers available and in use which may be advantageous in the saving of test time, permit the use of smaller samples, and have other factors which may merit their use. If automatic testers are used, the user must ensure that all of the manufacturer's instructions for calibration, adjustment, and operation of the instrument are followed. It must be reported that the pour point was determined by an automatic instrument. Precision of automatic pour point testers has not been determined. In any case of dispute, the pour point as determined by the manual method described herein shall be considered the reference test.

7. Reagents and Materials 7.1 The following solvents of technical grade are appropriate for low-temperature bath media. 7.1.1 Acetone NOTE 2: Warning--Extremely flammable.

7.1.2 Alcohol, Ethanol NOTE 3: WarningmFlammable.

7.1.3 Alcohol, Methanol NOTE 4: Warnlng--Flammable. Vapor harmful.

7.1.4 Petroleum Naphtha NOTE 5: Warning---Combustible. Vapor harmful. 7.1.5 Solid Carbon Dioxide NOTE 6: Warning--Extremely cold -78.5°C.

8. Procedure 8.1 Pour the specimen into the test jar to the level mark. When necessary, heat the specimen in a water bath until it is just sufficiently fluid to pour into the test jar.

mo Available from ASTM Headquarters. Request RR:D02-1377.

88

10 D 97 replacement shall require not more than 3 s. 8.6.1 If the specimen has not ceased to flow when its temperature has reached 27"C, transfer the test jar to the next lower temperature bath in accordance with the following schedule: Specimen Specimen Specimen Specimen Specimen

is at is at is at is at is at

in 7.1 through 7.7 is the upper (maximum) pour point. If required, determine the lower (minimum) pour point by heating the sample while stirring to 105*C, pouring it into the jar, and determining the pour point as described in 7.4 through 7.7.

+27°C, move to 0°C bath, +9°C, move to -18"C bath, -6°C, move to -33"C bath, -24"C, move to -51"C bath, -42"C, move to -69°C bath.

9. Calculation and Report 9.1 Add 3"C to the temperature recorded in 7.7 and report the result as the Pour Point, ASTM D 97. For black oil, and so forth, add 3"C to the temperature recorded in 7.7 and report the result as Upper Pour Point, ASTM D 97, or Lower Pour Point, ASTM D 97, as required.

8.6.2 As soon as the specimen in the jar does not flow when tilted, hold the jar in a horizontal position for 5 s, as noted by an accurate timing device and observe carefully. If the specimen shows any movement, replace the test jar immediately in the jacket and repeat a test for flow at the next temperature, 3"C lower. 8.7 Continue in this manner until a point is reached at which the specimen shows no movement when the test jar is held in a horizontal position for 5 s. Record the observed reading of the test thermometer.

lO. Precision and Bias 10.I Lubricating Oil and Distillate and Residual Fuel Oil.2 10.1.1 Repeatability--The difference between successive test results, obtained by the same operator using the same apparatus under constant operating conditions on identical test material, would in the long run, in the normal and correct operation of this test method, exceed 3"C only in one case in twenty. Differences greater than this should be considered suspect. 10.1.2 Reproducibility--The difference between two single and independent test results, obtained by different operators working in different laboratories on identical test material, would in the long run, in the normal and correct operation of this test method, exceed 6"C only in one case in twenty. Differences greater than this should be considered suspect.

NOTE 8--To determine compliance with existing specifications having pour point limits at temperatures not divisible by YC, it is acceptable practice to conduct the pour point measurement according to the following schedule: Begin to examine the appearance of the specimen when the temperature of the specimen is 9"C above the specification pour point. Continue observations at 3"C intervals as described in 7.6 and 7.7 until the specificationtemperature is reached. Report the sample as passing or failing the specification limit. 8.8 For black specimen, cylinder stock, and nondistillate fuel specimen, the result obtained by the procedure described THERMOMETER

44.2 - 45.8 I9. 3e - 32.4 I D 332 - 3'~80D

CORK

JACKET 25 MAX.

I~ L TEST JAR FILL

LEVEL

GASKET

COOLING

BATH

~o

L

DIS< N O ~ E ~ X . ' m i O e S are in ~

(not to scale). FIG. 1

Apparatus for Pour Point Test

89

COCLANT LEVEL

~) D 97 10.2 Bias--There being no criteria for measuring bias in these test-product combinations, no statement of bias can be made. 10.3 The precision statements were prepared with data on ten new (unused) mineral oil-based lubricants and sixteen assorted fuel oils tested by twelve cooperators. The mineral oil-based lubricants had pour points ranging from - 4 8 to

-6"C while the fuel oils had pour points ranging from - 3 3 to +51 °C. The following precision data were obtained:

95 % Confidence Repeatability, "C Reproducibility, *C

Mineral Oil Lubricants

Fuel Oils

2.87 6.43

2.52 6.59

APPENDIX

(Nonmandatory Information) Xl. TEST FOR FLUIDITY OF A RESIDUAL F U E L OIL AT A SPECIFIED T E M P E R A T U R E Xl.1 General

cooled at the specified temperature for 30 rain in the standard U-tube and is tested for movement under prescribed pressure conditions.

X I.I.1 The low-temperature flow properties of a waxy fuel oil depend on handling and storage conditions. Thus, they may not be truly indicated by pour point. The pour point test does not indicate what happens when an oil has a considerable head of pressure behind it, such as when gravitating from a storage tank or being pumped along a pipeline. Failure to flow at the pour point is normally attributed to the separation of wax from the fuel; however, it can also be due to the effect of viscosity in the case of very viscous fuel oils. In addition pour points of residual fuels are influenced by the previous thermal history of the specimens. A loosely knit wax structure built up on cooling of the oil can be normally broken by the application of relatively little pressure. X1.1.2 The usefulness of the pour point test in relation to residual fuel oils is open to question, and the tendency to regard the pour point as the limiting temperature at which a fuel will flow can be misleading. The problem of accurately specifying the handling behavior of fuel oil is important, and because of the technical limitations of the pour point test, various pumpability tests have been devised to assess the low-temperature flow characteristics of heavy residual fuel oils. Test Method D 3245 is one such method. However, most alternative methods tend to be time-consuming and as such do not find ready acceptance as routine control tests for determining low-temperature flow properties. One method which is relatively quick and easy to perform and has found limited acceptance as a "go-no-go" method is based on the appendix method to the former Test Method D 1659 - 65. The method is described as follows.

Xl.5 Significance and Use X1.5.1 This method may be used as a "go-no-go" procedure for operational situations where it is necessary to ascertain the fluidity of a residual oil under prescribed conditions in an as-received condition. The conditions of this method simulate those of a pumping situation where the oil is expected to flow through a 12-mm pipe under slight pressure at a specified temperature. Fluidity, like Test Method D 97, is used to define cold flow properties. It differs from D 97, however, in that (a) it is restricted to residual fuel oil and (b) a prescribed pressure is applied to the sample. The latter represents an attempt to overcome the technical limitations of the Pour Point Method where gravity-induced flow is the criterion. Test Method D 3245, represents another method for predicting field performance in cold flow conditions. Test Method D 3245, however, does have limitations and may not be suitable for use with very waxy fuel oils which solidify so rapidly in the chilling bath that a reading cannot be obtained under the conditions of the test. It is also a time-consuming test and therefore not suitable for routine control testing.

Xl.6 Apparatus Xl.6.1 Glass U-Tubes, 150 m m high, having a uniform internal diameter of 12.5 + 1 m m and a radius of curvature, measured to the outside curve of the tube of 35 m m (Fig. Xl.l). XI.6.2 Thermometers--Thermometers having a range from - 3 8 to +50"C and conforming to the requirements of Thermometer 5C as prescribed in Specification E 1, shall be used for insertion in the glass U-tubes and for measuring the temperatures of the baths. XI.6.3 Fluidity Temperature Test Bath ~ consists of a reservoir, a stirrer, and a motor and pump to circulate coolant through the coils of the tubing placed in the bottom of the test bath and passing through the cold bath. The flow of coolant through these coils can be controlled by a thermostat and a solenoid valve. It is possible that, where

Xl.2 Scope X I.2.1 This method covers the determination of the

fluidity of a residual fuel oil at a specified temperature in an as-received condition.

Xl.3 Definition X1.3.1 fluidity temperature--the sample when tested in an as-received condition is considered "fluid at the temperature of the test" if it will flow 2 m m in 1 min in a 12.5 m m U-tube under a maximum pressure of 152 m m of mercury.

Xl.4 Summary of Test Method X 1.4.1 A sample of fuel in its as-received condition is

t I A kinematic viscosity bath is usually satisfactory.

90

ll~ D 97 ASTM 5C Thermometer

To Vacuum Controller

Bung

2J/l ,

I

Bath Medium

150

l

75 m

Sample~ _ NOTE--NI dimensionsare In mlmeVes FIG. X1.1

I)iq~

of U-tube in Flukll~/Tea~pemture Test Bath

Xl.7 Preparation of Apparatus

justified by the quantity of work, more than one such bath could be utilized to permit concurrent testing at more than one temperature (Fig. X1.2). X1.6.4 Mercury Manometer calibrated in lO-mm divisions with a distinguishing mark at 152 m m (equivalent to 20.3 Ida). X1.6.5 Automatic Vacuum Controller 12 as shown in Figs XI.3 and XI.4---a device that gradually increased the vacuum applied to one end of the U-tube at the specified rate of I0 mm/4S.

XI.7.1 Adjust the automatic vacuum controller as follows: close the stopcock on the tube connecting the automatic vacuum controller to the fluidity tester. A pinchcock on the rubber tube will serve as well as a stopcock. Wind the thread attached to the steel rod around the pulley on the synchronous motor until the end of the rod is about 15 m m above the zero level of the mercury in the control manometer. Turn on the power switch. The thread will begin to unwind, lowering the steel rod. When the rod contacts the mercury, the relay will open the solenoid valve in the vacuum line and air will be pumped from the system at a rate limited by the needle valve. Adjust this needle valve

t2 T I ~ appmatus may be shop fabricated. Details of special parts ate indicated in Figs. XI.3 and XI.4. Alternatively the appmatus can be purchased.

91

o 97 sample in the U-tube is 38 mm. Insert in one leg of each U-tube an ASTM Thermometer 5C in a cork that has been grooved to permit the passage of air. The thermometer must be placed in the center of the tube and its bulb immersed so that the beginning of the capillary is 3 m m below the surface of the specimen. X1.8.2 Fix the tube in the bath set at the specific temperature, immersed to a depth of approximately 75 ram. Control the bath and sample temperatures within __.I*C and _0.5"C, respectively, of the specified temperature of the test. XI.8.3 Maintain the sample at the specified temperature for 30 min __+ 30 s, with the U-tube connected to the

until the descending mercury in the control manometer just leads the rod, reducing the relay operation to a minimum. When properly adjusted, the pulsations caused by the opening and closing of the solenoid valve should not exceed +__1 ram. In this manner the pressure in the system will be reduced gradually at a rate governed by the descent of the steel rod. Xl.8 Procedure X1.8.1 Pour the sample as received into a thoroughly cleaned and dry standard fluidity U-tube, without contacting the upper walls of the tube, until the vertical height of the

FIG. X1.2

Fluidity Temperature Apparatus

92

dl~ D 97 C 0

Wiring

Diogrom

Flexible Wirey ~

O_

E E b

O3 ~r _.m

5~

355-mm

:

m Wire Iocl

0-ram Front

Bock View

View

+--26mm d~un.facepuny.

1 1 ~

2--Thread 3--Steel rod.

12~Syr~'-.-cq-~.~smoto¢.

cord to outlet

13--Plywood of approximately 10rnm thickness 14= M.'tliT~terscale.

4---Swltch-DPST. 5~Tee 90ram long. 6--Needle valve.

15~4 liter boffie 16--0.5 mm heat resistant gdassCal01ary. 17--To vaoJum line.

7--Rubber or plastic tublng. 8--6mm heat ~ glass tube. 9.--Solene~ valve. lO--Electric relay.

18---Rod hogder.

FiG. X l . 3

AssemMy Automatic Vacuum Controller Apparatus

thread. If the specimen has moved 2 mm or more during the time (1 min) the suction was applied, the specimen is considered fluid at the temperature of the test.

automatic vacuum controller, and the stopcock or pinchclamp open. Wind the thread on the pulley attached to the synchronous motor. Turn the power switch to the ON position. Apply suction automatically to the U-tube at the prescribed rate. Observe any movement of the specimen during a one-minute interval which is the time required to apply 152-mm Hg vacuum to the specimen in the U-tube. Immediately disconnect the U-tube from the automatic vacuum controller, turn off the power switch and rewind the

X1.9 Report X1.9.1 Report the fluidity of the sample at a specified temperature as follows: X 1.9.1.1 If the sample fulfdls the conditions of flow, as 93

(1~) D 97

1- rpm Synchronous Motor

6-m! ,,=-.--Thread

Steel

To Flu=dtty

Tester

,~

Face Pulley

Rod

~

-

A-Liter

To Vacuum

Bottle

~

Pump-,~---~-

>.-.---6- mm Heot-Resistant

Needle Volvo

220/110V

--

Gloss Tube

-

i

AC¢

i

o.5-mm

Heot-Ressstont Gloss Copdlary

Mercury------;~

FIG. Xl.4 Detail of Automatic Vacuum Controller defined in X l.3.1, report fluidity: "Fluid at (temperature of test)" or fluidity at (temperature of test): "Pass." X I.9.1.2 If the sample does not fulfill the conditions of flow, as defined in X1.3.1, report fluidity: "Not fluid at (temperature of test)" or fluidity at (temperature of test): "Fail."

XI.IO Precision and Bias X l. 10.1 As in the case of pass-fail data, no statement is made about either the precision or the bias of this method for measuring the fluidity of a residual fuel specimen since the result merely states whether there is conformance to the criteria for success specified in the procedure.

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, end the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee end must be reviewed every five years and if not revised, either reepproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at • meeting of the responsible technical committee, which you may attend, ff you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 100 Barr Harbor Drive, West Conshohockeno PA 19428.

94

Designation: D 127 - 87 (Reapproved 1993) el

IPW lrNL INSI'ITU~ IW r t l r l l o t J m ~ l

An American Na~n~ Standard of Pu~ md Paper Industry Tmtaavl MethodT 634ta-64

Technical ~

Designation: 133/79 (87)

Standard Test Method for Drop Melting Point of Petroleum Wax Including Petrolatum 1 This standard is issued under the fixed designation D 127; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (0 indicates an editorial change since the last revision or reapproval.

This test method is sponsoredjoimly by the TechnicalAssociation of Pulp and Paper Industry and the American Societyfor Testing and Materials. This test method was adopted as a joint ASTM-IP standard in 1964. This test method has been adoptedfor use by government agencies to replace Method 1401 of Federal Test Method Standard No. 791b. ~t NOTE--Keywords were added editorally in October 1993.

I. Scope I.I This test method covers the determination of the drop melting point of petroleum wax. It is used primarily for petrolatums and other microcrystalline wax.

ture at which material becomes sufficiently fluid to drop from the thermometer used in making the determination under definite prescribed conditions.

NOTE l--Additional methods used for petroleum waxes are Test Method D 87 and Test Method D 938. Resultsobtained may differ, depending on the method used. For pharmaceuticalpetrolatum,Test Method D 127 usuallyisused.

4. Summary of Test Method 4.1 Specimens are deposited on two thermometer bulbs by dipping chilled thermometers into the sample. The thermometers bearing the specimens are placed in test tubes and heated by means of a water bath until the specimens melt and the first drop falls from each thermometer bulb. The average of the temperatures at which these drops fall is the drop melting point of the sample.

1.2 The values stated in SI units are to be regarded as the standard. The values in parentheses are for information only.

1.3 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

5. Significance and Use 5.1 Melting point is a wax property that is of interest to most wax consumers. It can be an indication of the performanc¢ properties of the wax. Drop melting point, Test Method D 127, is oRen used to measure the melting characteristics of petrolatums and other high viscosity petroleum waxes.

2. Referenced Documents

2.1 ASTM Standards: D 87 Test Method for Melting Point of Petroleum Wax (Cooling Curve) 2 D 938 Test Method for Congealing Point of Petroleum Waxes, Including Petrolatum 2 E 1 Specification for ASTM Thermometers 3

6. Apparatus 6.1 Test Tubes--Standard test tubes, 25 mm (1 in.) in outside diameter and 150 mm (6 in.) long. The test tubes shall be supplied with corks grooved at the sides to permit air circulation and bored in the exact center to receive the thermometer. 6.2 Bath--A transparent container of not less than I S00mL capacity, that will permit the immersion of the test tubes to a depth of at least I00 mrn and still leave a depth of I S mm of water below the bottoms of the test tubes. 6.3 Thermometer, having a range as shown below and conforming to the requirements as prescribed in Specifications E 1 or in specifications for IP Standard Thermometers:

3. Definition

3.1 drop melting point of petroleum wax--The temperai This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of subcommittee 1302.10 on Properties of Petroleum Wax. In the IP, this method is under the jurisdiction of Standardization Committee. Current edition approved Oct. 30, 1987. Published December 1987. Originally published as D 127 - 22. Last previous edition D 127 - 63 (1982). In 1963, the title, scope, and definition were changed to define the determination of "drop melting point." Sections on procedure, report, and precision were revised, and a new section on significance was added. In 1964, minor editorial changes and additions to this method were made for its publication as a joint ASTM-IP standard. 2 Annual Book of ASTM Standards, Vo105.01. 3 Annual Book of ASTM Standards, Vols 05.03 and 14.03.

Thermometer Number

95

Thermometer Range

ASTM

lP

32 to 127"C 90 to 260"F

61C 61F

63C

~1~ D 127 6.4 Bath Thermometer, any suitable type, accurate to 0.5"C (I'F) throughout the required range.

8. Report 8.1 Report the average of the two determinations as the drop melting point of the sample under test.

7. Procedure 7.1 Secure a sample of sufficient size that is representative of the material under inspection. Use a fresh portion of the sample for each set of two determinations. Melt the sample slowly until the temperature reaches 93"C (200"F), or about 1 I°C (20°F) above the expected drop melting point, whichever is higher. Place sufficient sample in a flat bottom container to give a sample depth of 12 + 1 ram. Adjust the temperature ofthe sample to 6 to 1 I'C (10 to 20"F) (Note 2) above its drop melting point using any general laboratory thermometer for measurement. Chill one of the test thermometer bulbs to 4"C (40"F). Wipe dry, and, quickly but carefully, immerse the chilled bulb vertically into the heated sample until it touches the bottom of the container (12 mm submerged) and withdraw it immediately. Hold the thermometer vertically away from the heat until the surface dulls, and then place it for 5 rain in water having a temperature of 16°C (60"F). Prepare another specimen from the same sample using this procedure.

9. Precision and Bias

9.1 Precision--The precision of this test method as determined by statistical examination of interlaboratory results is as follows: 9.1.1 Repeatability-The difference between two test results, obtained by the same operator with the same apparatus under constant operating conditions on identical test material, would in the long run, in the normal and correct operation of the test method, exceed the following values only in one case in twenty: 0.8"C (I.4"F)

9.1.2 Reproducibility.-Thedifference between two single and independent results obtained by different operators working in different laboratories on identical test material would, in the long run, in the normal and correct operation of the test method, exceed the following values only in one case in twenty: 1.3°C (2.4"F) NOTe 3--The following information on the precision of this test method has been developedby the Institute of Petroleum (London) and is being investigated: (a) Results of duplicate tests should not differ by more than the followingamounts: Repeatability Reproducibility

NOTE 2--A dipping temperature of I I'C (20"1=) above the congealing point in accordance with Test Method D 938 usually will be 6 to 1I'C (10 to 20"1:) above the actual drop melting point.

7.2 Securely fix the thermometers in the test tubes by means of corks so that the tip of each thermometer is 15 mm above the bottom o f its test tube. Insert the test tubes in the water bath which is at 16°C (60"F) and adjust the height of the test tubes so that the immersion marks on the thermometers are level with the top surface of the water. Raise the temperature of the bath at a rate of (3"1=) 1.7"C/min to 38"C (100°F), then at a rate of I'C (2"F)/min until the first drop of material leaves each thermometer. Record in each case the temperature at which the first drop falls from the thermometer.

I'C (2"F)

1.2"C (2.2"F)

(b) These precision values were obtained in 1954 by statistical examination of inteflaboratory test results. 9.2 Bias--The procedure in this test method has no bias because the value of drop melting point can be defined only in terms of a test method. 10. Keywords 10.1 drop melting point; petrolatum; petroleum wax; wax

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any Item mentioned in this standard. Users of this standard ere expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and If not revised, either respproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive oareful oonsldarMIon at a meeting of the responslbie technical committee, which you may attend. If you feel that your comments have not received e fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103.

96

Designation: D 130 - 94

IPW

An American Natiomd Standard Federation of Societies for Paint Tectmok:,~/Standard NO. Dt-28-65 British Standard 4351

Designation: 154/93

Standard Test Method for Detection of Copper Corrosion from Petroleum Products by the Copper Strip Tarnish Test This standard is issued under the fixed designation D 130; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (() indicates an editorial change since the last revision or reapproval. This is also a standard of the Institute of Petroleum issued under the fixed designation IP 154. The final number indicates the year of last revision.

This test method has been approved by the sponsoring committees and accepted by the cooperating societies in accordance with established procedures. This standard has been approved for use by agencies of the Department of Defense to replace Method 5325 of Federal Test Method Standard No. 791h. Cnnsult the DoD Index nf Specificalions and Standards for the specific year of issue which has been adopted by the Department qJ De]¢'nw.

2.2 ASTM Adjunct." Copper Strip Corrosion Standard 3

1. Scope 1.1 This test method covers the detection of the corrosiveness to copper of aviation gasoline, aviation turbine fuel, automotive gasoline, natural gasoline or other hydrocarbons having a Reid vapor pressure no greater than 18 psi (124 kPa) (Caution--see Note 1 and Annex A2.), cleaners (Stoddard) solvent, kerosine, diesel fuel, distillate fuel oil, lubricating oil, and certain other petroleum products.

3. Summary of Test Method 3.1 A polished copper strip is immersed in a given quantity of sample and heated at a temperature and for a time characteristic of the material being tested. At the end of this period the copper strip is removed, washed, and compared with the ASTM Copper Strip Corrosion Standards.

NOTE I: C a u t i o n - - S o m e products, particularly natural gasoline, m a y have a m u c h higher vapor pressure than would normally be characteristic o f automotive or aviation gasolines. For this reason, extreme caution m u s t be exercised to ensure that the test b o m b containing natural gasoline or other products o f high vapor pressure are not placed in the 100°C (212"F) bath. Samples having Reid vapor pressures in excess of 18 psi (124 kPa) m a y develop sufficient pressure at 100"C to cause rupture of the test b o m b . For a n y sample having a Reid vapor pressure above 18 psi (124 kPa), use Test Method D 1838.

4. Significance and Use 4. I Crude petroleum contains sulfur compounds, most of which are removed during refining. However, of the sulfur compounds remaining in the petroleum product, some can have a corroding action on various metals and this corrosivity is not necessarily related directly to the total sulfur content. The effect can vary according to the chemical types of sulfur compounds present. The copper strip corrosion test is designed to assess the relative degree of corrosivity of a petroleum product.

1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements, see Notes 1 and 2, and Annex A2.

5. Apparatus 5.1 Test Tubes, 25 by 150-ram. 5.1.1 Provide a bath capable of being maintained at a constant temperature of 50 ± I'C (122 ± 2"17) or 100 :t: I°C (212 + 2°F), or both, and having suitable supports to hold the test tubes in a vertical position and immersed to a depth of about 100 mm (4 in.). Either water, oil, or aluminum block baths are suitable. 5.2 Copper Strip Corrosion Test Bomb, constructed of stainless steel according to the dimensions as given in Fig. 1, and capable of withstanding a test pressure of 100 psi (689 kPa). Alternative designs for the bomb cap and synthetic rubber gasket may be used provided that the internal dimensions of the bomb are the same as those shown in Fig.

2. Referenced Documents

2.1 ASTM Standards: D 396 Specification for Fuel Oils 2 D 975 Specification for Diesel Fuel Oils 2 D 1655 Specification for Aviation Turbine Fuels2 D 1838 Test Method for Copper Strip Corrosion by Liquefied Petroleum (LP) Gases 2 J This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee I)02.05 on Physical Analysis of Fuels and Light Distillates. In the IP, this test method is under the jurisdiction of the Standardization Committee. Currenl edition approved Feb. 15. 1994. Published April 1994. Originally published as D 1 3 0 - 2 2 T , replacing former D89. Last previous edition D 130 - 88. 2 Anmlal Book O[..ISTM Standard~. Vol 05.01.

J Available from ASTM Headquarters, 1916 Race Street, Philadelphia, PA. 19103. Request Adjunct No. 12-401300-00. Names of suppliers in the United Kingdom can be obtained from the Institute of Petroleum. Two master standards are held by the IP for reference.

97

~ 3,2 WIDEGROOVEFORPRESSURERELIEF

(v,")

D 130

../- LIFTING EYE

/-KNURLEB CAP

~'SYNTHETIC RUBBER'O' RING FREE FROM FREE SULPHUR ,\ ~--CHttMFER INSIDE CAP TO PROTECT 'O' RING WHEN CLOSING BOMB

TPI NF THREAD (OR EQUIVALENT)

I~t~-12

MAX TEST PRESSURE lOB LBF/IN z (?O3Kg~mz) ---

-16 WALL SEAMLESS TUBE ('h6") MATERIAL' STAINLESS STEEL WELDED CONSTRUCTION

. . . .

_ g'IT////NZ///A~

FIG. 1 Copper Strip Corrosion Test Bomb

1. Provide a 25 by 150-mm test tube as a liner for holding the sample. 5.2.1 Provide liquid baths capable of being maintained at 40 _+_I*C (104 ___2*F) or 100 ± I'C (212 +__2*F), or both, and having suitable supports to hold the test bomb in a vertical position. The bath must be deep enough so that the entire bomb will be submerged during the test. As the bath medium, use water or any other liquid which can be satisfactorily controlled at the specified test temperatfare. 5.3 Thermometers, total immersion, for indicating the required test temperature, with smallest graduations of I*C (2*F) or less. No more than 25 mm (1 in.) of the mercury thread should extend above the surface of the bath at the test temperature. The ASTM 12C (12F) or IP 64C (64F) thermometer is suitable. 5.4 Polishing Vise, for holding the copper strip firmly without marring the edges while polishing. Any convenient type of holder (see Appendix) may be used provided that the strip is held tightly and that the surface of the strip being polished is supported above the surface of the holder. 5.5 Viewing Test Tubes, flat glass test tubes, are convenient for protecting corroded strip for close inspection or storage (see Appendix). 6. Materials

6.1 Wash Solvent--Any volatile, sulfur-free hydrocarbon solvent may be used provided that it shows no tarnish at all when tested at 50"C (122"F). Knock test grade isooctane is a suitable solvent and should be used in case of dispute. NOTE 2: Warning--Extremely flammable, see Annex A2.1.

to 3.0 mm (V,6 to I/8 in.) thick, cut 75 mm (3 in.) long from smooth-surfaced, hard-temper, cold-finished copper of 99.9 + % purity; electrical bus bar stock is generally suitable (see Appendix). The strips may be used repeatedly but should be discarded when the surfaces become deformed on handling. 6.3.2 Surface Preparation--Remove all surface blemishes from all six sides of the strip with silicon carbide paper of such degrees of fineness as are needed to accomplish the desired results efficiently. Finish with 65-1am (240-grit) silicon carbide paper or cloth, removing all marks that may have been made by other grades of paper used previously. Immerse the strip in wash solvent from which it can be withdrawn immediately for final preparation (polishing) or in which it can be stored for future use. 6.3.2.1 As a practical manual procedure for surface preparation, place a sheet of the paper on a fiat surface, moisten it with kerosine or wash solvent, and rub the strip against the paper with a rotary motion, protecting the strip from contact with the fingers with an ashless filter paper. Alternatively, the surface of the strip can be prepared by use of motor-driven machines using appropriate grades of dry paper or cloth. 6.3.3 Final PreparationmRemove a strip from the wash solvent. Holding it in the fingers protected with ashless filter paper, polish first the ends and then the sides with the 105-1~m (150-mesh) silicon carbide grains picked up from a clean glass plate with-a pad of cotton (cotton wool) moistened with a drop of wash solvent. Wipe vigorously with fresh pads of cotton (cotton wool) and subsequently handle only with stainless steel forceps; do not touch with the fingers. Clamp in a vise and polish the main surfaces with siliconcarbide grains on absorbent cotton. Do not polish in a circular motion. Rub in the direction of the long axis of the strip, carrying the stroke beyond the end of the strip before reversing the direction. Clean all metal dust from the strip by rubbing vigorously with clean pads of absorbent cotton until a fresh pad remains unsoiled. When the strip is clean, immediately immerse it in the prepared sample. 6.3.3.1 It is important to polish the whole surface of the strip uniformly to obtain a uniformly stained strip. If the edges show wear (surface elliptical) they will likely show more corrosion than the center. The use of a vise (see Appendix) will facilitate uniform polishing. 6.3.3.2 It is important to follow the order of preparation with the correctly sized silicon carbide material as described in 6.3.2 and 6.3.3. The final preparation is with 105-1~m silicon carbide grains. This is a larger grain size than the 65 micron paper used in the surface preparation stage. The reason for this use of larger silicon carbide grains in the final preparation is to produce asperities (controlled roughness) on the surface of the copper which acts as sites for the initiation of corrosion reactions. 7. Corrosion Standards

7.1 ASTM Copper Strip Corrosion Standards 4 consist of reproductions in color of typical test strips representing increasing degrees of tarnish and corrosion, the reproductions being encased in plastic in the form of a plaque. 7.1.1 Keep the plastic-encased printed ASTM Copper Strip Corrosion Standards protected from light to avoid the possibility of fading. Inspect for fading by comparing two different plaques, one of which has been carefully protected

6.2 Polishing Materials--Silicon carbide grit paper of varying degrees of fineness including 65-~tm (240-grit) paper or cloth; also a supply of 105-1am (150-mesh) silicon carbide grain and pharmaceutical grade absorbent cotton (cotton

wool). 6.3 Copper Strips: 6.3. I Specification--Use strips 12.5 mm (t/2 in.) wide, 1.5 98

D 130 from light (new). Observe both sets in diffused daylight (or equivalent) first from a point directly above and then from an angle of 45*. When any evidence of fading is observed, particularly at the left-hand end of the plaque, it is suggested that the one that is the more faded with respect to the other be discarded. 7.1.1.1 Alternatively, place a 20-mm (3/4-in.) opaque strip (masking tape) across the top of the colored portion of the plaque when initially purchased. At intervals remove the opaque strip and observe. When there is any evidence of fading of the exposed portion, it is suggested that the standards be replaced. 7.1.1.2 These plaques are full-color reproductions of typical strips. They have been printed on aluminum sheets by a 4-color process and are encased in plastic for protection. Directions for their use are given on the reverse side of each plaque. 7.1.2 If the surface of the plastic cover shows excessive scratching it is suggested that the plaque be replaced. 8. Samples 8.1 It is particularly important that all types of fuel samples, which pass a low-tarnish strip classification, be collected in clean, dark glass bottles, plastic bottles, or other suitable containers that will not affect the corrosive properties of the fuel. Avoid the use of tin plate containers for collection of samples, since experience has shown that they may contribute to the corrosiveness of the sample. 8.2 Fill the containers as completely as possible and close them immediately after taking the sample. Take care during sampling to protect the samples from exposure to direct sunlight or even diffused daylight. Make the test as soon as possible after receipt in the laboratory and immediately after opening the container. 8.3 When suspended water (haze) is observed in the sample, dry by filtering a sufficient volume of sample through a medium rapid qualitative filter, into the prescribed clean, dry test tube. Carry out this operation in a darkened room or under a light-protected shield. 8.3.1 Contact of the copper strip with water before, during, or after the completion of the test run, will cause staining, making it difficult to evaluate the strips. 9. Procedure 9.1 Those product classes, to which given procedural variations are intended to be applied, are listed below. Some product classes, being quite broad, may be tested by more than one set of conditions; in such cases the copper strip quality requirement for a given product should be limited to a single set of conditions. The conditions of time and temperature given below are those most commonly used and are quoted in the ASTM specifications for these products where such specifications exist. However, other conditions can also be used as and when required by specifications or by agreement between parties.

into the test bomb (Fig. I) and screw the lid on tight. Completely immerse the bomb in a boiling water bath at 100 -4- I*C (212 ___2*F). After 2 h _ 5 min in the bath, withdraw the bomb and immerse for a few minutes in tap water. Open the bomb, withdraw the test tube and examine the strip as described in 9.2. 9.1.2 For natural gasoline--Carry out the test exactly as described in 9.1.1 but at 40"C (104*F) and for 3 h + 5 min. 9.1.3 For diesel fuel, fuel oil, automotive gasolinemPlace 30 mL of sample, completely clear and free of any suspended or entrained water (see 8.3), into a chemically clean, dry 25 by 150-ram test tube and, within 1 min after completing the final preparation (polishing), slide the copper strip into the sample tube. Stopper with a vented cork and place in a bath maintained at 50 _ I°C (122 ___2°F) (see 5.1.1). Protect the contents of the test tube from strong light during the test. After 3 h + 5 rain in the bath, examine the strip as described in 9.2. For tests on fuel oil and diesel fuel, to specifications other than Specifications D 396 and D 975, a temperature of 100°C (212"F) for 3 h is often used as an alternative set of conditions. 9.1.4 For cleaners (Stoddard) solvent and kerosine-Carry out the test exactly as described in 9.1.3 but at 100 :t: I*C (212:1: 2*F). 9.1.5 For lubricating oilmTests can be carried out for varying times and at elevated temperatures other than 100°C (212°F). For the sake of uniformity, it is suggested that even increments of 50°F beginning with 250"F (or Celsius equivalents to the nearest whole degree) be used. 9.2 Strip Examination. 9.2.1 Empty the contents of the test tube into a 150-mL tall-form beaker, letting the strip slide in gently so as to avoid breaking the beaker. Immediately withdraw the strip with stainless steel forceps and immerse in wash solvent. Withdraw the strip at once, dry with quantitative filter paper (by blotting and not by wiping), and inspect for evidences of tarnishing or corrosion by comparison with the Copper Strip Corrosion Standards. Hold both the test strip and the standard strip plaque in such a manner that light reflected from them at an angle of approximately 45" will be observed. 9.2.2 In handling the test strip during the inspection and comparison, the danger of marking or staining can be avoided if it is inserted in a flat glass tube (see Appendix X l) which can be stoppered with absorbent cotton.

10. Interpretation 10.1 Interpret the corrosiveness of the sample accordingly as the appearance of the test strip agrees with one of the strips of the ASTM Copper Strip Corrosion Standards. 10.1.1 When a strip is in the obvious transition state between that indicated by any two adjacent standard strips, judge the sample by the more tarnished Standard Strip. Should a strip appear to have a darker orange color than Standard Strip l b, consider the observed strip as still belonging in Classification 1; however, if any evidence of red color is observed, the observed strip belongs in Classification 2. 10.1.2 A claret red strip in Classification 2 can be mistaken for a magenta overcast on brassy strip in Classification 3 if the brassy underlay of the latter is completely masked by a magenta overtone. To distinguish, immerse the strip in

9.1.1 For aviation gasoline, and aviation turbine fuelm Place 30 mL of sample, completely clear and free of any suspended or entrained water (see 8.3) into a chemically clean, dry 25 by 150-ram test tube, and within 1 min after completing the final preparation (polishing), slide the copper strip into the sample tube. Carefully slide the sample tube 99

~ TABLE 1 Classif'mation

D 130

Copper Strip Classifications

Designation

Description A

Freshly polished strip

...

e

1

sl~jht tamish

a. Light orange, almost the same as freshly polished strip b. Dark orange

2

moderate tarnish ... •.. ... •..

a. b. c. d. e.

3

dark tarnish ...

a• Magenta overcast on brassy strip b. Multicolored with red and green =~owlng (peacock), but no gray

4

corrosion •.. •..

a. Transparent black, dark gray or brown with peacock green barely showing b. Graphite or lusteriess black c. Glossy or jet black

Claret red Lavender Muiticcdored with lavender blue or silver, or both, ovedaid on claret red Silvery Brassy or gold

A The ASTM Copper Strip Corrosion Standard is a colored reproduction of strips characteristic of these descriptions. a The freshly polished strip is included in the series only as an indication of the appearance of a propedy polished strip before a test run; it is not possible to dul~icete this appearance after a test even with a completely noncorrosive sample.

the greater portion of the strip; in this case it is likely that the edges were burnished during preparation (polishing).

wash solvent; the former will appear as a dark orange strip while the latter will not change. 10.1.3 To distinguish multicolored strips in Classifications 2 and 3, place a test strip in a 20 by 150-mm test tube and bring to a temperature of 315 to 370"C (600 to 700*F) in 4 to 6 min with the tube lying on a hot plate. Adjust to temperature by observing a high distillation thermometer inserted into a second test tube. If the strip belongs in Classification 2, it will assume the color of a silver and then a gold strip, if in Classification 3 it will take on the appearance of a transparent black, etc., as described in Classification 4. 10.1.4 Repeat the test if blemishes due to finger prints are observed, or due to spots from any particles of water droplets that may have touched the test strip during the digestion period. 10.1.5 Repeat the test also if the sharp edges along the flat faces of the strip appear to be in a classification higher than

11. Report 11.1 Report the corrosiveness in accordance with one of the classifications listed in Table 1. State the duration of the test and the test temperature.

12. Precision and Bias 12.1 In the case of pass/fail data no generally accepted method for determining precision or bias is currently available. 13. Keywords 13.1 automotive gasoline; aviation gasoline; aviation turbine fuel; copper corrosion; copper strip finish; corrosiveness to copper; natural gasoline

ANNEXES

(Mandatory Information) AI. COPPER Q U A L I T Y AI.I Copper Quality A I. 1.1 Hard-temper, cold-finished type-(ETP) electrolytic tough pitch copper. 4

4 Conforming to Copper Development Assn. (CDA), United States of America No. 110, or to British Standard (BS) 1036: 1952, which have proper quality•

A2. PRECAUTIONARY STATEMENT

A2.1 Isooctane

Avoid prolonged breathing of vapor or spray mist. Avoid prolonged or repeated skin contact.

Harmful if inhaled• Vapors may cause flash fire. Keep away from heat, sparks, and open flame. Keep container closed. Use with adequate ventilation. Avoid build-up of vapors and eliminate all sources of ignition, especially nonexplosion proof electrical apparatus and heaters.

A2.2 Aviation Turbine Fuel (Jet A or A-l, see Specification D 1655) Keep away from heat, sparks, and open flames. Keep container closed. Use with adequate ventilation. I00

0

D 130

Avoid build-up of vapors and eliminate all sources of ignition, especially nonexplosion-proof electrical apparatus and heaters. Avoid prolonged breathing of vapor or spray mist. Avoid prolonged or repeated skin contact.

Avoid breathing vapor or spray mist. Avoid prolonged or repeated contact with skin. A2.3 Gasoline (Containing Lead) Keep away from heat, sparks, and open flame. Keep container closed. Use with adequate ventilation. Avoid build-up of vapors and eliminate all sources of ignition, especially nonexplosion-proof electrical apparatus and heaters. Avoid prolonged breathing of vapor or spray mist. Avoid prolonged or repeated skin contact.

A2.5 Kerosine Keep away from heat, sparks, and open flame. Keep container closed. Use with adequate ventilation. Avoid breathing vapor or spray mist. Avoid prolonged or repeated contact with skin. A2.6 Stoddard Solvent Keep away from heat, sparks, and open flame. Keep container closed. Use with adequate ventilation. Avoid breathing vapor or spray mist. Avoid prolonged or repeated contact with skin.

A2.4 Gasoline (White or Unleaded) Keep away from heat, sparks, and open flame. Keep container closed. Use with adequate ventilation.

APPENDIX (Nonmandatory Information) XI. OPTIONAL USEFUL EQUIPMENT XI.I Viewing Tube X I. !. 1 A useful flat glass test tube for holding tarnished copper strips for inspection or for storage for later inspection is illustrated and dimensioned in Fig. X 1.1.

•

Xl.2 Strip Vise X I.2.1 A useful and convenient vise for holding up to four copper strips during final polishing is illustrated and dimensioned in Fig. X 1.2.

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Designation: D 189 - 97

IPW TIN. i % t i i H i n tit ptll~tl41 thl

AMERICAN SOCIETY FOR TESTING AND MATERIALS 100 Ban" Harbor Dr., West Conshehocken, PA 19428 Repnnted from the Annual Book of ASTM Standards. Copynght ASTM If not listed in the current combined index, will appear in the next edition.

An Amedcan NatkmaJ Stsndud Bttlsh Standard 4380

Designation: 13/94

Standard Test Method for Conradson Carbon Residue of Petroleum Products I This standard is issued under the fixed designation D 189; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of lust reapproval. A supel~ript epsilon (0 indicates an editorial change since the last revision or reapproval. This is also a standard of the Institute of Petroleum issued under the fixed designation IF 13. The final number indicates the year of last revision.

This test method has been approved for use by agencies of the Department of Defense. Consult the DaD Index of Specifications and Standards for the specOqcyear of issue which has been adopted by the Department of Defense. This method was adopted as a joint ASTM~IP standard in 1964. This method has been adoptedfor use by government agencies to replace Method 5001 of Federal Test Method Standard No. 791b.

1. Scope 1.1 This test method covers the determination of the amount of carbon residue (Note 1) left after evaporation and pyrolysis of an oil, and is intended to provide some indication of relative coke-forming propensities. This test method is generally applicable to relatively nonvolatile petroleum products which partially decompose on distillation at atmospheric pressure. Petroleum products containing ash-forming constituents as determined by Test Method D 482 or IP Method 4 will have an erroneously high carbon residue, depending upon the amoiant of ash formed (Notes 2 and 4). NOTE l - - T h e

standard. T h e values given in parentheses are for information only.

1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 2. Referenced Documents

2.1 A S T M Standards: D 482 Test Method for Ash from Petroleum Products 2 D 524 Test Method for Ramsbottom Carbon Residue of Petroleum Products 2 D 4046 Test Method for Alkyl Nitrate in Diesel Fuels by Spectrophotometry3 D4057 Practice for Manual Sampling of Petroleum and Petroleum Products 3 D4175 Terminology Relating to Petroleum, Petroleum Products, and Lubricants 3 D 4177 Practice for Automatic Sampling of Petroleum and Petroleum Products 3 D4530 Test Method for Determination o f Carbon Residue (Micro Method) 3 E l Specification for ASTM Thermometers4 E 133 Specification for Distillation Equipment 5

t e r m carbon residue is used t h r o u g h o u t this test

method to designate the carbonaceous residue formed after evaporation and pyrolysis of a petroleum product. The residue is not composed entirely of carbon, but is a coke which can be further changed by pyrolysis.The term carbon residueis continued in this test method only in deferenceto its wide common usage. NOTE 2--Values obtained by this test method are not numerically the same as those obtained by Test Method D 524. Approximate correlations have been derived (see Fig Xl.l), but need not apply to all materials which can be tested because the carbon residue test is applied to a wide variety of petroleum products. NOTE 3--The testresultsare equivalent to Test Method D 4530, (see Fig. XI.2). Note 4---In diesel fuel, the presence of alkyl nitrates such as arnyl

nitrate, hexyl nitrate, or oetyl nitrate causes a higher residue value than observed in untreated fuel, which can lead to erroneous conclusions as

to the coke forming propensity of the fuel. The presence of alkyl nitrate in the fuel can be detected by Test Method D 4046.

3. Terminology

1.2 The values stated in SI units are to be regarded as the

3.1 Definitions: 3.1.1 carbon residue, n - - t h e residue formed by evaporation and thermal degradation of a carbon containing material. D 4175 3.1.1.1 Discussion--The residue is not composed entirely of carbon but is a coke that can be further changed by carbon pyrolysis. The term carbon residue is retained in deference to its wide common usage.

t This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibili't¥ of Subcommittee D02.06 on Analysis of Lubricants. Current edition approved Jan. 10, 1997. Published October 1997. Ot~inally published as D 189 - 24 T. Last previous edition D 189 - 95. In the IP, this method is under the jurisdiction of the Standardization Committee. This procedure .is a modification of the original Conradson method and apparatus for Carbon Test and Ash Residue in Petroleum Lubricating Oils. See Proceedings, Eighth International Congress of Applied Chemistry, New York, Vol 1, p. 131, September 1912; also Journal oflndustrial and Engineering Chemistry, IECHA, Voi 4, No. 11, December 1912. In 1965, a new Fig. 2 on reproducibility and repeatability combining ASTM and IP precision data replaced old Fig. 2 and Note 4.

2 Annual Book of ASTM Standards, Vol 05.01. s Annual Book of ASTM Standards, Vo105.02. 4 Annual Book of ASTM Standards, Vol 14.03. 5 Annual Book of ASTM Standards, Vol 14.02.

103

~)

D 189 an ash-forming detergent additive may increase the carbon residue value of an oil yet will generally reduce its tendency to form deposits. 5.3 The carbon residue value ofgas oil is useful as a guide in the manufacture of gas from gas oil, while carbon residue values of crude oil residuums, cylinder and bright stocks, are useful in the manufacture of lubricants.

4. Summary of Test Method 4.1 A weighed quantity of sample is placed in a crucible and subjected to destructive distillation. The residue undergoes cracking and coking reactions during a fixed period of severe heating. At the end of the specified heating period, the test crucible containing the carbonaceous residue is cooled in a desiccator and weighed. The residue remaining is calculated as a percentage of the original sample, and reported as Conradson carbon residue.

6. Apparatus (see Fig. 1)

6.1 Porcelain Crucible, wide form, glazed throughout, or a silica crucible; 29 to 3 l-mL capacity, 46 to 49 mm in rim diameter. 6.2 Iron Crucible--Skidmore iron crucible, flanged and ringed, 65 to 82-mL capacity, 53 to 57 mm inside and 60 to 67 mm outside diameter of flange, 37 to 39 mm in height supplied with a cover without delivery tubes and having the vertical opening closed. The horizontal opening of about 6.5 mm shall be kept clean. The outside diameter of the flat bottom shall be 30 to 32 mm. 6.3 Iron Crucible--Spun sheet-iron crucible with cover;, 78 to 82 mm in outside diameter at the top, 58 to 60 mm in height, and approximately 0.8 mm in thickness. Place at the bottom of this crucible, and level before each test, a layer of

5. Significance and Use 5.1 The carbon residue value of burner fuel serves as a rough approximation of the tendency of the fuel to form deposits in vaporizing pot-type and sleeve-type burners. Similarly, provided alkyl nitrates are absent (or if present, provided the test is performed on the base fuel without additive) the carbon residue of diesel fuel correlates approximately with combustion chamber deposits. 5.2 The carbon residue value of motor oil, while at one time regarded as indicative of the amount of carbonaceous deposits a motor oil would form in the combustion chamber of an engine, is now considered to be of doubtful significance due to the presence of additives in many oils. For example, 150-175 120-130 50 -56

I

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FIG. 1 Apparatus for DeterminingConradsonCarbon Residue 104

q~ D 189 about 25 mL of dry sand, or enough to bring the Skidmore crucible, with cover on, nearly to the top of the sheet-iron crucible. 6.4 Wire Support--Triangle of bare Nichrome wire of approximately No. 13 B & S gage having an opening small enough to support the bottom of the sheet-iron crucible at the same level as the bottom of the asbestos block or hollow sheet-metal box (6.6). 6.5 HoodmCircular sheet-iron hood from 120 to 130 mm in diameter the height of the lower perpendicular side to be from 50 to 53 mm; provided at the top with a chimney 50 to 60 mm in height and 50 to 56 mm in inside diameter, which is attached to the lower part having the perpendicular sides by a cone-shaped member, bringing the total height of the complete hood to 125 to 130 ram. The hood can be made from a single piece of metal, provided it conforms to the foregoing dimensions. As a guide for the height of the flame above the chimney, a bridge made of approximately 3-mm iron or Nichrome wire, and having a height of 50 mm above the top of the chimney, shall be attached. 6.6 InsulatormAsbestos block, refractory ring, or hollow sheet-metal box, 150 to 175 mm in diameter if round, or on a side if square, 32 to 38 mm in thickness, provided with a metal-lined, inverted cone-shaped opening through the center; 83 mm in diameter at the bottom, and 89 mm in diameter at the top. In the case of the refractory ring no metal lining is necessary, providing the ring is of hard, heat-resistant material. 6.7 Burner, Meker type, having an orifice approximately 24 mm in diameter.

crucible for the purpose of igniting the vapors. Then remove the heat temporarily, and before replacing adjust by screwing down the pinch-cock on the gas tubing so that the ignited vapors burn uniformly with the flame above the chimney but not above the wire bridge. Heat can be increased, if necessary, when the flame does not show above the chimney. The period of burning the vapors shall be 13 ± 1 min. If it is found impossible to meet the requirements for both flame and burning time, the requirement for burning time is the more important. 8.4 When the vapors cease to burn and no further blue smoke can be observed, readjust the burner and hold the heat as at the beginning so as to make the bottom and lower part of the sheet-iron crucible a cherry red, and maintain for exactly 7 min. The total period of heating shall be 30 ± 2 min, which constitutes an additional limitation on the tolerances for the pre-ignition and burning periods. There should be no difficulty in carrying out the test exactly as directed with the gas burner of the type named, using city gas (20 to 40 MJ/m3), with the top of the burner about 50 mm below the bottom of the crucible. The time periods shall be observed with whatever burner and gas is used. 8.5 Remove the burner and allow the apparatus to cool until no smoke appears, and then remove the cover of the Skidmore crucible (about 15 min). Remove the porcelain or silica crucible with heated tongs, place in the desiccator, cool, and weigh. Calculate the percentage of carbon residue on the original sample.

7. Sampling 7.1 For sampling techniques see Practices D 4057 and D4177. 8. Procedure 8.1 Shake thoroughly the sample to be tested, f'wstheating to 50° + 1O°Cfor 0.5 h when necessary to reduce its viscosity. Immediately following the heating and shaking, filter test portion through a 100 mesh screen. Weigh to the nearest 5 mga 1O-gsample of the oil to be tested, free of moisture and other suspended matter, into a tared porcelain or silica crucible containing two glass beads about 2.5 mm in diameter. Place this crucible in the center of the Skidmore crucible. Level the sand in the large sheet-iron crucible and set the Skidmore crucible on it in the exact center of the iron crucible. Apply covers to both the Skidmore and the iron crucible, the one on the latter fitting loosely to allow free exit to the vapors as formed. 8.2 On a suitable stand or ring, place the bare Nichrome wire triangle and on it the insulator. Next center the sheet-iron crucible in the insulator with its bottom resting on top of the triangle, and cover the whole with the sheet-iron hood in order to distribute the heat uniformly during the process (see Fig. 1). 8.3 Apply heat with a high, strong flame from the Mekcr-type gas burner, so that the pre-ignition period will be I0 ± 1.5 rain (a shorter time can start the distillation so rapidly as to cause foaming or too high a flame). W h e n smoke appears above the chimney, immediately move or tilt the burner so that the gas flame plays on the sides of the 105

9. Procedure for Residues Exceeding 5 % 9.1 This procedure is applicable to such materials as heavy crude oils, residuums, heavy fuel oils, and heavy gas oils. 9.2 When the carbon residue as obtained by the procedure described in Section 8 (using a 1O-g sample) is in excess of 5 %, difficulties can be experienced due to boiling over ofthe sample. Trouble also can be encountered with samples of heavy products which are difficult to dehydrate. 9.3 For samples showing more than 5.0 and less than 15.0 % carbon residue by the procedure described in 6.1, repeat the test using a 5 + 0.5 g sample weighed to the nearest 5 rag. In event that a result greater than 15.0 % is obtained, repeat the test, reducing the sample size to 3 + 0.1 g, weighed to the nearest 5 mg. 9.4 If the sample boils over, reduce the sample size fwst to 5 g and then to 3 g as necessary to avoid the difficulty. 9.5 When the 3-g sample is used, it can be impossible to control the preignition and vapor burning times within the limits specified in 8.3, and in such cases, the results are valid. 10. Procedure for Carbon Residue on 10 % Distillation Residue 10.1 This procedure is applicable to light distillate oils, such as ASTM No. 1 and No. 2 fuel oils. 10.2 Assemble the distillation apparatus described in Specification E 133 using flask D (250-mL bulb volume), flask support board with 51-ram diameter opening, and graduated cylinder C (200-mL capacity). A thermometer is not required but the use of the ASTM High Distillation Thermometer 8F or 8C as prescribed in Specification E 1 or the IP High Distillation Thermometer 6C, as prescribed in

D 189

then represents a 10 % distillation residue from the original product. 10.6 While the distillation residue is warm enough to flow freely, pour approximately 10 + 0.5 g of it in the previously weighed crucible to be used in the carbon residue test. After cooling, determine the weight of the sample to the nearest 5 mg and carry out the carbon residue test in accordance with the procedure described in Section 8.

the IP Thermometer Specifications is recommended. 10.3 Place a volume of sample equivalent to 200 mL at 13 to 18°C in the flask. Maintain the condenser bath at 0 to 4°C (for some oils it may be necessary to hold the temperature between 38 and 60°C to avoid solidification of waxy material in the condenser tube). Use, without cleaning, the cylinder from which the sample was measured as the receiver and place it so that the tip of the condenser does not touch the wall of the cylinder. 10.4 Apply the heat to the flask at a uniform rate so regulated that the first drop of condensate exits from the condenser between 10 and 15 min after initial application of heat. After the fn'st drop falls, move the receiving cylinder so that the tip of the condenser tube touches the wall of the cylinder. Then regulate the heat so that the distillation proceeds at a uniform rate of 8 to 10 mL/min. Continue the distillation until 178 mL of distillate has been collected, then discontinue heating and allow the condenser to drain until 180 mL (90 % of the charge to the flask) has been collected in the cylinder. 10.5 Immediately replace the cylinder with a small Erlenmeyer flask and catch any final drainage in the flask. Add to this flask, while still warm, the distillation residue left in the distilling flask, and mix well. The contents of the flask

11. Calculation 11.1 Calculate the carbon residue of the sample or of the 10 % distillation residue as follows: Carbon residue = (A x IO0)IW (1) where: A = mass of carbon residue, g, and W = mass of sample, g. 12. Report

12.1 Report the value obtained as Conradson Carbon Residue, percent or as Conradson Carbon Residue on 10 % distillation residue, percent, Test Method D 189.

5 4 3

O5

z

03 0.2

0.1 w

¢r

w .05

.05 .02

.01

.005.01

.02 .03

,05

0,1

0.2 O5

0.5

I

2

3

CONRADSON CARBON RESIDUE, AVERAGE %. NoTe--Log n - 0.B92 + 0.847 log x + 0.087 (log x)e Log R - -0.516 + 0.676 Log x + 0.050 (log x)• x - average of ~ being compared

FIG. 2

Precision 106

5

IO

20

30

189 13. Precision and Bias 6 13.1 The precision of this test method as determined by statistical examination of interlaboratory results is as follows: 13.1.1 RepeatabiiityRThe difference between two test results, obtained by the same operator with the same apparatus under constant operating conditions on identical test material would, in the long run, in the normal and correct operation of the test method, exceed the values shown in Fig. 2 only in one case in twenty. 13.1.2 Reproducibility--The difference between two

single and independent results obtained by different operators working in different laboratories on identical test material would, in the long run, in the normal and correct operation of the test method, exceed the values shown in Fig. 2 only in one case in twenty. NOTe 5--Precision is based on data developed using inch-pound units. See Test Method D 189 - 76. 13.2 BiasoThis test method is based on empirical results and no statement of bias can be made. 14. Keywords 14.1 Conradson carbon residue; lubricants; petroleum products

e Supporting data are available from ASTM Headquarters. Request RR:D021227.

APPENDIX (Nonmandatory Information) X1. INFORMATION CONCERNING CORRELATION OF CARBON RESIDUE RESULTS DETERMINED BY METHODS D 189, D 524, AND D 4530 X 1.1 No exact correlation of the results obtained by Test Methods D 189 and D 524 exists because of the empirical nature of the two tests. However, an approximate correlation

(Fig. X 1.1) has been derived by ASTM Committee D-2 from the cooperative testing of 18 representative petroleum products and confirmed by further data on about 150 samples

6O 40

3O 2O o~ < >. ca izt.u o rr t.t.I o,.

10 8 6

4 3 2 ~

1.0

~ z o ~

0.8 0.6 0.4

o

0.3

o

0.2

al IE a:

/

0.10 0.08

f

0.06~ ~ " 0'04 I 0.03 0.02 0.01 I O.Ol

0.03 0.03

0.06 0.10

0.2 0,3 0.4 0.60.8 L0

2

3 4

6 8 10

CONRADSON CARBON RESIDUE, PER CENT BY MASS (ASTM D 189)

FIG. X1.1

Correlation Data

107

20 30 40

6080100

~1~ D 189

J /

J f

e/e'Je ,~

FIG. Xl.2

10 15 20 MICRO C~BON R£SXDUE {'t BY MASS)

25

30

Correla~on of Conradson and Micro Carbon Residue Tests

which were not tested cooperatively. Test results by both methods on unusual types of petroleum products need not fall near the correlation line of Fig. XI. 1. Caution should be exercised in the application of this approximate relation to samples of low carbon residues.

X 1.2 A direct correlation of the results obtained by Test Methods D 189 and D4530 has been derived by ASTM Committee D-2 as shown in Fig. X 1.2. Supporting data have been filed at ASTM Headquarters as RR:D02-1192.

The Amerlcan Society for Tutlng and Materlals takes no posltlon respecting the validity of any patent rlghts asserteclln connection with any item ~ In this standard. Users of this ~ d are expressly advised that determination of the validity of any such patent ttghtl, end the risk of ~ of such rights, ere entirely their own ~ l i t y . This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five yeat~ and If not revised, either mN3~oved or withdrawn. Your cornmen~ are Invited either for revision of this stw~dardor for additional standards and should be a d d ~ to ASTM Headquarters. Your comments will receive careful consideration at • meeting of the r e s ~ b l e technical ¢~rnmlttee, which you may attend, ff you feel that your comments have not received a fair he~lng you should make your views known to the A~TM ~ on Standarde, 100 Bur Harbor Drive, West CoP.thohocken, PA 19428.

108

(~T~ Designation:D287-92

An American National Standard

Standard Test Method for API Gravity of Crude Petroleum and Petroleum Products (Hydrometer Method) 1 This standard is issued under the fixed designation D 287; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (d indicates an editprial change since the last revision or reapproval.

Thts test method has been adoptedfor use by government agencies to replace Method 401 of Federal Test Method Standard No. 791b.

1. Scope 1.1 This test method covers the determination by means of a glass hydrometer of the API gravity of crude petroleum and petroleum products normally handled as liquids and having a Reid vapor pressure (Test Method D 323) of 26 psi ( 180 kPa) or less. Gravities are determined at 60*F (I 5.56"C), or converted to values at 60*F, by means of standard tables. These tables are not applicable to nonhydrocarbons or essentially pure hydrocarbons such as the aromatics. NOTE l--The internationalversionofthis test methodis describedin Test Method D 1298. 1.2 Values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are provided for information purposes only. 1.3 This standard does not purport to address all of the

4. Summary of Test Method 4.1 This test method is based on the principle that the gravity of a liquid varies directly with the depth of immersion of a body floating in it. The floating body, which is graduated by API gravity units in this method, is called an API hydrometer. 4.2 The API gravity is read by observing the freely floating API hydrometer and noting the graduation nearest to the apparent intersection of the horizontal plane surface of the liquid with the vertical scale of the hydrometer, after temperature equilibrium has been reached. The temperature of the sample is read from a separate accurate ASTM thermometer in the sample or from the thermometer which is an integral part of the hydrometer (thermohydrometer). 5. Significance and Use 5.1 Accurate determination of the gravity of petroleum and its products is necessary for the conversion of measured volumes to volumes at the standard temperature of 60°F (15.56"C). 5.2 Gravity is a factor governing the quality of crude oils. However, the gravity of a petroleum product is an uncertain indication of its quality. Correlated with other properties, gravity can be used to give approximate hydrocarbon composition and heat of combustion.

safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applica. bifity of regulatory limitations prior to use. For specific hazard statements, see Notes 3 and 4.

2. Referenced Documents

2.1 A S T M Standards: D323 Test Method for Vapor Pressure of Petroleum Products (Reid Method)2 D 1250 Guide for Petroleum Measurement Tables 2 D 1298 Practice for Density, Relative Density (Specific Gravity), or API Gravity of Crude Petroleum and Liquid Petroleum Products by Hydrometer Method2 E 1 Specification for ASTM Thermometers3 E 100 Specification for ASTM Hydrometers3

6. Apparatus 6.1 Hydrometers, of glass, graduated in degrees API as listed in Table 1 and conforming to Specification E 100, or the IP Specifications for Petroleum Hydrometers. 6.2 Thermometers, having a range from - 5 to +2150F and conforming to the requirements for Thermometer 12F as prescribed in Specification E 1 or Thermometer 64F of the Specifications for IP Standard Thermometers. A thermometer is not required if a thermohydrometer is employed. NOTE 2--The ASTM GravityThermometer 12F has 0.5"F subdivisionsand allowable+0.25"Fscaleerror. The thermometersincorporated in thermohydrometershave 2*F subdivisionsand allowable+I'F scale error.

3. Terminology

3.1 Definitions: 3.1.1 API gravityma special function of relative density (specific gravity) 60/60"F (15.56/15.56"C), represented by: API gravity,deg = (141.5/sp gr 60/60"F) - 131.5 No statement of reference temperature is required, since 60*F is included in the definition.

6.3 Hydrometer Cylinders, of metal, clear glass, or plastic. For convenience in pouring, the cylinder may have a lip on the rim. The inside diameter of the cylinder shall be at least 25 mm greater than the outside diameter of the hydrometer used in it. The height of the cylinder shall be such that the length of the column of sample it contains is greater by at least 25 mm than the portion of the hydrometer which is immersed beneath the surface of the sample. For field testing, a sampling thief of suitable dimensions may be used.

This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants, and is the direct responsibility of Subcommittee D02.04 on Hydrocarbon Analysis. Current edition adopted Aug. 15, 1992. Published October 1992. Originally published as D 2 8 7 - 2 8 T , replacing former D47. Last previous edition D 287 - 82 (1987) ~l. 2 Annual B¢u~k of ASTM Standards, Vol 05.01. .1Anmzal B¢n~k o./'ASTM Standards, Vols 05.03 and 14.03.

109

D 287 TABLE 1 Demgnatlon 1H to 10H 21H to 40H 51H to 60H 71H to 74H A

8.4 Lower the hydrometer gently into the sample and, when it has settled, depress it about two scale divisions into the liquid and then release it; keep the rest of the stem dry, as unnecessary liquid on the stem changes the effective weight of the instrument, and so affects the reading obtained. With samples of low viscosity, a slight spin imparfed to the instrument on releasing assists in bringing it to rest, floating freely away from the walls of the hydrometer cylinder. Allow sufficient time for the hydrometer to become completely stationary and for all air bubbles to come to the surface. This is particularly necessary in the case of the more viscous samples. 8.5 When the hydrometer has come to rest, floating freely, and the temperature of the sample is constant to 0.2"F (0.1"C), read the hydrometer to the nearest scale division. The correct reading is that point on the hydrometer scale at which the surface of the liquid cuts the scale. Determine this point by placing the eye slightly below the level of the liquid and slowly raising it until the surface, first seen as a distorted ellipse, appears to become a straight line cutting the hydrometer scale. 8.6 To make a reading with nontransparent liquids, observe the point on the hydrometer scale to which the sample rises above its main surface, placing the eye slightly above the plane surface of the liquid. This reading requires a correction. Determine this correction for the particular hydrometer in use by observing the height above the main surface of the liquid to which the sample rises on the hydrometer scale when the hydrometer in question is immersed in a transparent liquid having a surface tension similar to that of a sample under test. 8.7 Observe the temperature of the sample to the nearest 0.25"F (0. l'C) immediately before and after the observation of the gravity, the liquid in the cylinder being thoroughly but cautiously stirred with the thermometer (Note 5), and the whole of the mercury thread being immersed. Should these temperature readings differ by more than I'F (0.5"C), repeat the temperature and gravity observations when the temperature of the sample has become more stable. Record the mean of the thermometer reading before and after the final hydrometer reading, to the nearest 1°F, as the temperature of the test.

Available Hydrometers Scaled, Degrees API Type long plain short plain thermo thermo thermo

API Range, dog Series Total

EachUnit

-1 to 101 0 to 101 -1 to 101 -1 to 41 15 to 51

12 6 12 12 8

Scale Division Error 0.1 0.1 0.1 0.1

0,1 0.2 0.1 0,1

'~ Eight-degree range thermohydrometers are available.

7. Temperature of Test 7.1 The gravity determined by the hydrometer method is most accurate at or near the standard temperature of 60*F (15.56*C). Use this or any other temperature between 0 and 195*F (-18 and +90°C) for the test, so far as it is consistent with the type of sample and necessary limiting conditions shown in Table 2. 8. Procedure 8.1 For referee testing, use the long plain form of hydrometer (1H to 10H). For field testing, use the thermohydrometer. 8.2 Adjust the temperature of the sample in accordance with Table 2. For field testing, test temperatures other than those listed in Table 2 may be used. The hydrometer cylinder shall be approximately the same temperature as the sample to be tested. 8.3 Transfer the sample into the clean hydrometer cylinder without splashing, so as to avoid the formation of air bubbles and to reduce to a minimum the evaporation of the lower boiling constituents of the more volatile samples. (Warning--see Note 3.) For the more volatile samples, transfer to the hydrometer cylinder by siphoning. (WarningmSec Note 4.) Use a rubber aspirator bulb. Remove any air bubbles formed, after they have collected on the surface of the sample, by touching them with a piece of clean filter paper before inserting the hydrometer. For field testing, make the gravity measurement directly in the sampling thief. Place the cylinder containing the sample in a vertical position in a location free from air currents. Take precautions to prevent the temperature of the sample from changing appreciably during the time necessary to complete the test. During this period, the temperature of the surrounding medium should not change more than 50F (2°C).

NOTE 5--When thermohydmmeters are used, stir the sample by carefully raising and lowering the hydrometer. It is satisfactoryin this case to read the thermometer scale after the hydrometer reading has been observed.Read the thermometer to the nearest I'F (0.5"C).

NOTE 3--Warning--Extremely flammable. Vapors may cause flash fire. NOTE 4--Warning--Do not start the siphon by mouth. TABLE 2 Sample Type

Gravity Limits

LimiUng

Conditions and Testing Temperatures

Initial Boiling UmitsPoint

Highly volatile

lighter than 70° API

Moderately volatile

heavier than 70° API

below 250=F (120°C)

Moderately volatile and viscous

heavier than 70° API

below 250°F (120*C)

Nonvolatile

heavier than 70° API

above 250°F (120°C)

Mixtures of nonpetroleum products or essentially pure hydrOcerbons

110

Other Umits

Viscosity too high' at 65*F (18°C)

Test Temperature Cool to 35°F (2°C) or lower in original closed contalnor. Cool to 650F (18°C) or lower in original dosed container. Heat to minimum temperature for sufficient fluidity. Any temperature between 0 and 195°F (-18 and 90"C) as convenient. 60 + 0.25°F (15.56:1: 0.1=C)

O

o

9. Calculation 9.1 When gravities have been observed on opaque liquids using the procedure given in 8.6, subtract the correction from the hydrometer reading observed. 9.2 Correct all hydrometer readings to 60*F (15.56"C), using Tables 5A or 5B of Guide D 1250.

=st correct operation of the test method, exceed 0.2" API only in one case in twenty. 11.1.2 Reproducibility--The difference between two single and independent results, obtained by different operators, working in different laboratories on identical test material, would in the long run, in the normal and correct operation of the test method, exceed 0.5* API only in one case in twenty.

10. Report 10.1 Report the corrected hydrometer reading as degrees API (*API) or as API Gravity.

NOTE 6--The precision for this method was not obtained in accordance with RR:D02-1007) NOTE 7--This precision statement applies only to measurements made at temperatures differing from 60"F (15.56"C) by less than 18"F (10"c).

11. Precision and Bias 11.1 The precision of this test method as obtained by statistical examination of inteflaboratory test results is as follows: 11.1.1 Repeatability--The difference between successive test results obtained by the same operator with the same apparatus under constant operating conditions on identical test material, would in the long run, in the normal and

I 1.2 BiasmBias for this method has not been determined.

12. Keywords 12.1 API gravity; crude petroleum; thermohydrometer; thermometer

The American Society for Testing and Materials takes no position respecting the vahdity of any patent rights asserted in connection with any item mentioned in this standard. Users o1 this standard are expressly adwsed that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be rewewed every five years and if not revised, either reapproved or withdrawn. Your comments are inwted either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you ~should make your views known to the ASTM Committee on Standards, 100 Barr Harbor Drive, West Conshohocken, PA 19428.

111

hydrometer;

~]~

Designation: D 323 - 94 Standard Test Method for Vapor Pressure of Petroleum Products (Reid Method) 1 This standard is issued under the fixed designation D 323; the number immediately following the designation indicates the year of odginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (E) indicates an editorial change since the last revision or rcapproval.

This standard has been approved for use by agencies of the Department of Defense, Consult the DoD Index of Specifications and Standards for the specific year of issue which has been adopted by the Department of Defense.

D4057 Practice for Manual Sampling of Petroleum and Petroleum Products 3 D 4953 Test Method for Vapor Pressure of Gasoline and Gasoline-Oxygenate Blends (Dry Method) 4 E 1 Specification for ASTM Thermometers 5

1. Scope 1. I This test method covers procedures for the determination of vapor pressure (See Note 1) of gasoline, volatile crude oil, and other volatile petroleum products. Procedure A is applicable to gasoline and other petroleum products with a vapor pressure of less than 180 kPa (26 psi). Procedure B may also be applicable to these other materials, but only gasoline was included in the interlaboratory test program to determine the precision of this test method. Neither procedure is applicable to liquefied petroleum gases or fuels containing oxygenated compounds other than methyl t-butyl ether (MTBE) (See Note 2). Procedure C is for materials with a vapor pressure of greater than 180 kPa (26 psi) and Procedure D for aviation gasoline with a vapor pressure of approximately 50 kPa (7 psi).

3. Summary of Test Method 3.1 The liquid chamber of the vapor pressure apparatus is filled with the chilled sample and connected to the vapor chamber that has been heated to 37.8"C (100*F) in a bath. The assembled apparatus is immersed in a bath at 37.8"C (100*F) until a constant pressure is observed. The reading, suitably corrected, is reported as the Reid vapor pressure. 3.2 All four procedures utilize liquid and vapor chambers of the same internal volume. Procedure B utilizes a semiautomatic apparatus immersed in a horizontal bath and rotated while attaining equilibrium. Either a Bourdon gage or pressure transducer may be used with this procedure. Procedure C utilizes a liquid chamber with two valved openings. Procedure D requires more stringent limits on the ratio of the liquid and vapor chambers.

NOTI/ l - - B e c a u s e the external atmospheric pressure is counteracted by the atmospheric pressure initially present in the vapor chamber, the Reid vapor pressure is an absolute pressure at 37.8"C (100*F) in kilopascals (pounds-force per square inch). T h e Reid vapor pressure differs from the true vapor pressure o f the sample due to s o m e small

sample vaporization and the presence of water vapor and air in the confined space. NOTE 2--For determination of the vapor pressure of liquified petroleum gases refer to Test Method D 1267. For determination of the vapor pressure of gasoline-oxygenate blends refer to Test Method D 4953.

4. Significance and Use 4.1 Vapor pressure is an important physical property of volatile liquids. This test method is used to determine the vapor pressure at 37.8"C (100*F) of petroleum products and crude oils with initial boiling point above 0*C (32"F). 4.2 Vapor pressure is critically important for both automotive and aviation gasolines, affecting starting, warmup, and tendency to vapor lock with high operating temperatures or high altitudes. Maximum vapor pressure limits for gasoline are legally mandated in some areas as a measure of air pollution control. 4.3 Vapor pressure of crude oils is of importance to the crude producer and the refiner for general handling and initial refinery treatment. 4.4 Vapor pressure is also used as an indirect measure of the evaporation rate of volatile petroleum solvents.

1.2 The values stated in SI units are to be regarded as the standard. The inch-pound units given in parentheses are provided for information only. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Specific precautionary statements are given in Sections 6 and 17, and Notes 5, 8, 11, 12, AI.I and AI.2.

2. Referenced Documents

2.1 A S T M Standards: D 1267 Test Method for Vapor Pressure of Liqueified Petroleum (LP) Gases (LP-Gas Method) 2

5. Apparatus 5.1 The required apparatus for Procedures A, C, and D is

i This test method is under the jurisdiction of ASTM Committee I)-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.08 on Volatility. Current edition approved Sept. 15, 1994. Published November 1994. Originally published as D 323 - 30. Last previous edition D 323 - 90. 2 Annual Book of ASTM Standards, Vol 05.01.

3 Annual Book of ASTM Standards, Vol 05.02. 4 Annual Book of ASTM Standards, Vol 05.03. 5 Annual Book of ASTM Standards, Vol 14.03.

112

~

O 323

described in Annex A1. Apparatus for Procedure B is described in Annex A2. 6 6. Hazards 6.1 Gross errors can he obtained in vapor pressure measurements if the prescribed procedure is not followed carefully. The following list emphasizes the importance of strict adherence to the precautions given in the procedure: 6.1.1 Checking the Pressure Gage--Check all gages against a manometer after each test in order to ensure higher precision of results (See 11.4). Read the gage while in a vertical position and after tapping it lightly. 6.1.2 Checking for Leaks~Check all apparatus before and during each test for both liquid and vapor leaks (See Note 6). 6.1.3 Sampling~Because initial sampling and the handling of samples will greatly affect the final results, employ the utmost precaution and the most meticulous care to avoid losses through evaporation and even slight changes in composition (See Section 9 and 11.1). In no case shall any part of the Reid apparatus itself be used as the sample container prior to actually conducting the test. 6.1.4 Purgingthe Apparatus--Thoroughly purge the pressure gage, the liquid chamber and the vapor chamber to be sure that they are free of residual sample. This is most conveniently done at the end of the test in preparation for the next test (See 11.5 and 14.5). 6.1.5 Coupling the Apparatus--Carefully observe the requirements of 11.2. 6.1.6 Shaking the Apparatus~Shake the apparatus vigorously as directed in order to ensure equilibrium.

working in different laboratories on identical test material would, in the long run, in the normal and correct operation of the test method, exceed the following value only in 1 case in 20. Range Reproducibility Procedure Ida psi Ida psi A Gasoline 35-100 5-15 5.2 0.75 Note 3 B Gasoline 35-100 5-15 4.5 0.66 Note 3 A 0-35 0-5 2.4 0.35 Note 4 A 110-180 16-26 2.8 0.4 Note 4 C >180 >26 4.9 0.7 Note 4 D Aviation Gasoline 50 7 1.0 0.15 Note 4 NOTS 3 - - T h e s e precision values are derived from a 1987 cooperative program 7 and the current Committee D-2 Statistical Method RR:D021007. NOTS 4 - - T h e s e precision values were developed in the early 1950's

prior to the current statistical evaluation method. 8.2 Bias: 8.2.1 AbsoluteBiasnSince there is no accepted reference material suitable for determining the bias for this test method, bias cannot be determined. The amount of bias between this test vapor pressure and true vapor pressure is unknown. 8.2.2 Relative BiasnThere is no statistically significant bias between Procedures A and B for gasolines as determined in the last cooperative test program. PROCEDURE A F O R P E T R O L E U M P R O D U C T S H A V I N G REID V A P O R P R E S S U R E S B E L O W 180 kPa (26 psi)

8.1.2 Reproducibility--Thedifference between two, single and independent results, obtained by different operators

9. Sampling 9.1 The extreme sensitivity of vapor pressure measurements to losses through evaporation and the resulting changes in composition is such as to require the utmost precaution and the most meticulous care in the handling of samples. The provisions of this section shall apply to all samples for vapor pressure determinations, except as specifically excluded for samples having vapor pressures above 180 kPa (26 psi); see Section 18. 9.2 Sampling shall be done in accordance with Practice D 4057. 9.3 Sample Container Size--The size of the sample container from which the vapor pressure sample is taken shall be 1 L (1 qt). It shall be 70 to 80 % f'flled with sample. 9.3.1 The present precision statement has been derived using samples in 1-L (1-qt) containers. However, samples taken in containers of other sizes as prescribed in Practice D 4057 can be used if it is recognized that the precision could be affected. In the case of referee testing, the I-L (1 -q0 sample container shall be mandatory. 9.4 The Reid vapor pressure determination shall be performed on the first test specimen withdrawn from the sample container. The remaining sample in the container cannot be used for a second vapor pressure determination. If necessary, obtain a new sample. 9.4.1 Protect samples from excessive heat prior to testing. 9.4.2 Do not test samples in leaky containers. They

6 Vapor pressure apparatus meeting the requirements of Procedure B are available from UIC Inc., PO Box 863, Joliet, IL 60434 or Walter Herzog GmbH, D-6970 Lauda-Konigshofen Postfach 320, West Germany.

7 The results of the cooperative test program from which these values have been derived are filed at ASTM Headquarters, 1916 Race St., Philadelphia, PA 19103. Request RR:D02-1245.

7. Report 7.1 Report the result observed in I 1.4 or 14.4, after correcting for any difference between the gage and manometer, to the nearest 0.25 kPa (0.05 psi) as the Reid vapor pressure. 8. Precision and Bias 8. I The following criteria are to be used for judging the acceptability of results (95 % confidence): 8.1.1 Repeatability--The difference between successive test results obtained by the same operator with the same apparatus under constant operating conditions on identical test material would, in the long run, in the normal and correct operation of the test method exceed the following value only in 1 case in 20. Procedure A Gasoline B Gasoline A A C D Aviation Gasoline

Range Ida psi 35-100 5-15 35-100 5-15 0-35 0-5 i 10-180 16-26 >180 >26 50

7

Repeatability Ida psi 3.2 0.46 1.2 0.17 0.7 0.10 2.1 0.3 2.8 0.4

Note 3 Note 3 Note 4 Note 4 Note 4

0.7

Note 4

0.1

113

~

D 323 and place the chamber in an inverted position over the top of the transfer tube. Invert the entire system rapidly so that the liquid chamber is upright with the end of the transfer tube approximately 6 mm (0.25 in.) from the bottom of the liquid chamber. Fill the chamber to overflowing. (See Note 5) Withdraw the transfer tube from the liquid chamber while allowing the sample to continue flowing up to complete withdrawal.

should be discarded and new samples obtained. 9.5 Sampling Handling Temperature--In all cases, cool the sample container and contents to 0 to I*C (32 to 34"F) before the container is opened. Sufficient time to reach this temperature shall be ensured by direct measurement of the temperature of a similar liquid in a like container placed in the cooling bath at the same time as the sample. 10. Preparation for Test 10.1 Verification of Sample Container Filling~With the sample at a temperature of 0 to I*C (32 to 34"F), take the container from the cooling bath, and unseal it. Using a suitable gage, confirm that the sample volume equals 70 to 80 % of the container capacity. 10.1.1 Discard the sample if its volume is less than 70 % of the container capacity. 10.1.2 If the container is more than 80 % full, pour out enough sample to bring the container contents within the 70 to 80 % range. Under no circumstances shall any sample poured out be returned to the container. 10.2 Air Saturation of Sample in Sample Container: 10.2.1 With the sample again at a temperature of 0 to I*C (32 to 34"F), take the container from the cooling bath, open it momentarily, reseal it, and shake it vigorously. Return it to the bath for a minimum of 2 min. 10.2.2 Repeat 10.2.1 twice more. Return the sample to the bath until the beginning of the procedure. 10.3 Preparation of Liquid Chamber--Completely immerse the open liquid chamber in an upright position and the sample transfer connection (See Fig AI.2) in a bath at 0 to I*C (32 to 34"F) for at least 10 rain. 10.4 Preparation of Vapor Chamber--After purging and rinsing the vapor chamber and pressure gage in accordance with 11.5, connect the gage to the vapor chamber. Immerse the vapor chamber to at least 25.4 mm (1 in.) above its top in the water bath maintained at 37.8 ± 0. I*C (100 + 0.2*F) for not less than 10 min just prior to coupling it to the liquid chamber. Do not remove the vapor chamber from the bath until the liquid chamber has been filled with sample as described in 11.1.

NOTE 5: Precaution--In additionto other precautions, make provision for suitablecontainmentand disposalof the overflowingsample to avoid fire hazard. 11.2 Assembly of Apparatus--Immediately remove the vapor chamber from the water bath and couple the filled liquid chamber to the vapor chamber as quickly as possible without spillage. When the vapor chamber is removed from the water bath, connect it to the liquid chamber without undue movement that could promote exchange of room temperature air with the 37.8"C (100*F) air in the chamber. Not more than 10 s shall elapse between removing the vapor chamber from the water bath and completion of the coupling of the two chambers. 11.3 Introduction of the Apparatus into BathmTurn the assembled apparatus upside down and allow all the sample in the liquid chamber to drain into the vapor chamber. With the apparatus still inverted, shake it vigorously eight times up and down. With the gage end up, immerse the assembled apparatus in the bath, maintained at 37.8 + 0.1*C (100 _ 0.2*F), in an inclined position so that the connection of the liquid and vapor chambers is below the water level and carefully examine for leaks (See Note 6). If no leaks are observed, further immerse the apparatus to at least 25 mm (1 in.) above the top of the vapor chamber. Observe the apparatus for leaks throughout the test and discard the test at anytime a leak is detected. NOTE 6--Liquid leaks are more difficult to detect than vapor leaks; and because the coupling between the chambers is normally in the liquid section of the apparatus, give it particular attention.

11.4 Measurement of Vapor Pressure--After the assembled apparatus has been in the water bath for at least 5 rain, tap the pressure gage lightly and observe the reading. Withdraw the apparatus from the bath and repeat the instructions of 11.3. At intervals of not less than 2 min, tap the gage, observe the reading and repeat 11.3 until a total of not less than five shaldngs and gage readings have been made. Continue this procedure, as necessary, until the last two consecutive gage readings are the same indicating that equilibrium has been attained. Read the final gage pressure to the nearest 0.25 kPa (0.05 psi) and record this value as the uncorrected vapor pressure of the sample. Without undue delay remove the pressure gage from the apparatus (See Note 7) without attempting to remove any liquid that may be trapped in the gage, check its reading against that of the manometer while both are subjected to a common steady pressure that is within 1.0 kPa (0.2 psi) of the recorded uncorrected vapor pressure. If a difference is observed between the manometer and gage readings, the difference is added to the uncorrected vapor pressure when the manometer reading is higher, or subtracted from the uncorrected vapor pressure when the manometer reading is lower, and

11. Procedure 11.1 Sample TransfermRemove the sample from the cooling bath, uncap, and insert the chilled transfer tube (See Fig. 1). Remove the liquid chamber from the cooling bath,

ChdlSampl ed e ~quldChamber

(a) (b) (c) Sample Container SeahngCloser GasohneChamber Pnof to Transler Replacedby Sample PlacedOver Liquid of Sampte TransferConnection DehveryTube FIG. 1

fd) Postt~onof Systemlet Sample Transler

Simplified Sketches Outlining Method Transferring Sample

to Liquid Chamber from Open-Type Containers

114

11~ D 323 the resulting value recorded as the Reid vapor pressure of the sample. Note 7--Coolingthe assemblyprior to disconnectingthe gage will fa"ctlitate disassemblyand reduce the amount of hydrocarbon vapors released into the room.

11.5 Preparationof Apparatus for Next Test: 11.5. I Thoroughly purge the vapor chamber of residual sample by filling it with warm water above 32"C (90*F) and allowing it to drain. Repeat this purging at least five times. Purge the liquid chamber in the same manner. Rinse both chambers and the transfer tube several times with petroleum naphtha, then several times with acetone, then blow dry using dried air. Place the liquid chamber in the cooling bath or refrigerator in preparation for the next test. 11.5.2 If the purging of the vapor chamber is done in a bath, be sure to avoid small films of floating sample by keeping the bottom and top openings of the chamber closed as they pass through the water surface. 11.5.3 Preparationof Gage--Disconnect the gage from its manifold connection with the manometer, remove trapped liquid in the Bourdon tube of the gage by repeated centrifugal thrusts. This is accomplished in the following manner: hold the gage between the palms of the hands with the right palm on the face of the gage and the threaded connection of the gage forward. Extend the arms forward and upward at an angle of 45*. Swing the arms rapidly downward through an arc of about 135" so that centrifugal force aids gravity in removing trapped liquid. Repeat this operation at least three times or until all liquid has been expelled from the gage. Connect the gage to the vapor chamber with the liquid connection closed and place in the 37.8"C (100*F) bath to condition for the next test. (See Note 8.) NOTE 8: CautionmDo not leave the vapor chamber with the gage attached in the water bath for a longerperiod of time than necessaryto condition for the next test. Water vapor can condensein the Bourdon tube and lead to erroneousresults. PROCEDURE B FOR PETROLEUM PRODUCTS HAVING REID VAPOR PRESSURES BELOW 180 kPa (26 psi), (HORIZONTAL BATH) 12. Sampling

12.1 Refer to Section 9. 13. Preparation for Test

13.1 Refer to Section 10. 14. Procedure

14.1 Sample Transfer--Remove the sample from the cooling bath, uncap, and insert the chilled transfer tube (see Fig. 1). Remove the liquid chamber from the cooling bath, and place the chamber in an inverted position over the top of the transfer tube. Invert the entire system rapidly so that the liquid chamber is upright with the end of the transfer tube approximately 6 mm (0.25 in.) from the bottom of the liquid chamber. Fill the chamber to overflowing. (See Note 5.) Withdraw the transfer tube from the liquid chamber while allowing the sample to continue flowing up to complete withdrawal. 14.2 Assembly of Apparatus--Immediately remove the vapor chamber from the water bath. Disconnect the spiral tubing at the quick action disconnect. Couple the filled

liquid chamber to the vapor chamber as quickly as possible without spillage or movement that could promote exchange of room temperature air with the 37.8"C (100*F) air in the vapor chamber. Not more than 10 s shall elapse between removing the vapor chamber from the water bath and completion of the coupling of the two chambers. 14.3 Introduction of the Apparatus into the Bath--While holding the apparatus vertically, immediately reconnect the spiral tubing at the quick action disconnect. Tilt the apparatus to 20 to 30* downward for 4 or 5 s to allow the sample to flow into the vapor chamber without getting into the tube extending into the vapor chamber from the gage, or pressure transducer. Place the assembled apparatus into the water bath maintained at 37.8 _+0.1*C (100 _+ 0.2*F) in such a way that the bottom of the liquid chamber engages the drive coupling and the other end of the apparatus rests on the support beating. Turn on the switch to begin the rotation of the assembled liquid-vapor chambers. Observe the apparatus for leakage throughout the test (See Note 6). Discard the test at anytime a leak is detected. 14.4 Measurement of Vapor Pressure--After the assembled apparatus has been in the bath for at least 5 min, tap the pressure gage lightly and observe the reading. Repeat the tapping and reading at intervals of not less than 2 rain, until two consecutive readings are the same. (Tapping is not necessary with the transducer model but the reading intervals should be the same.) Read the final gage or transducer pressure to the nearest 0.25 kPa (0.05 psi) and record this value as the uncorrected vapor pressure. Without undue delay disconnect the gage from the appartaus. Connect the gage or pressure transducer to a manometer. Check its reading against that of the manometer while both are subjected to a common steady pressure that is within 1.0 kPa (0.2 psi) of the recorded uncorrected vapor pressure. If a difference is observed between the manometer and gage or transducer readings, the difference is added to the uncorrected vapor pressure when the manometer reading is higher, or subtracted from the uncorrected vapor pressure when the manometer reading is lower, and the resulting value recorded as the Reid vapor pressure of the sample. 14.5 Preparation of Apparatusfor Next Test: 14.5.1 Thoroughly purge the vapor chamber of residual sample by filling it with warm water above 32"C (90*F) and allowing it to drain. Repeat this purging at least five times. Purge the liquid chamber in the same manner. Rinse both chambers and the transfer tube several times with petroleum naphtha, then several times with acetone, then blow dry using dried air. Place the liquid chamber in the cooling bath or refrigerator in preparation for the next test. (See Note 8.) 14.5.2 If the purging of the vapor chamber is done in a bath, be sure to avoid small films of floating sample by keeping the bottom and top openings of the chamber closed as they pass through the water surface. 14.5.3 Preparationof Gage or Transducer--In the correct operation of this procedure, liquid should not reach the gage or transducer. If it is observed or suspected that liquid has reached the gage, purge the gage as described in 11.5.3. The transducer has no cavity to trap liquid. Ensure that no liquid is present in the T handle fitting or spiral tubing by forcing a stream of dry air through the tubing. Connect the gage or 115

q~) D 323 transducer to the vapor chamber with the liquid connection closed and place in the 37.8"C (100*F) bath to condition for the next test.

in.) valve of the liquid chamber closed, open the outlet valve of the sample container and the 6.35-mm (0.25-in.) valve of the liquid chamber. Open the liquid chamber 12.7-ram (0.5-in.) valve slightly and allow the liquid chamber to fill slowly. Allow the sample to overflow until the overflow volume is 200 mL or more. Control this operation so that no appreciable drop in pressure occurs at the liquid chamber 6.35-mm (0.25-in.) valve. In the order named, close the liquid chamber 12.7-ram (0.5-in.) and 6.35-mm (0.25-in.) valves; and then close all other valves in the sample system. Disconnect the liquid chamber and the cooling coil. NOTE 11: Warning---Combustible.Keepawayfromheat,sparks, and open flame.Keep containerclosed. Use onlywith adequateventilation. Avoid prolonged breathing of vapor or spray mist. Avoid prolonged, repeated contactwith skin. NOTE 12: Precaution--In addition to other precautions, provide a safe means of disposal of liquid and vapor escaping during this whole operation.

PROCEDURE C FOR PETROLEUM PRODUCTS HAVINGREID VAPOR PRESSURES ABOVE 180 kPa (26 psi) 15. Introduction 15.1 With products having vapor pressure over 180 kPa (26 psi) (See Note 9), the procedure described in Sections 9 through 11 is hazardous and inaccurate. Consequently, the following sections define changes in apparatus and procedure for the determinations of vapor pressures above 180 kPa. Except as specifically stated, all the requirements of Sections I through 11 shall apply. NOTE 9--If necessary, either Procedure A or B can be used to determine if the vapor pressure of a product is above 180 kPa.

20.2.1 To avoid rupture because of the liquid-full condition of the liquid chamber, the liquid chamber must be quickly attached to the vapor chamber and the 12.7-ram (0.5-in.) valve opened. 20.3 Immediately attach the liquid chamber to the vapor chamber and open the liquid chamber 12.7-ram (0.5-in.) valve. Not more than 25 s shall pass in completing the assembly of the apparatus after filling the liquid chamber, using the following sequence of operations: 20.3.1 Remove the vapor chamber from the water bath. 20.3.2 Connect the vapor chamber to the liquid chamber. 20.3.3 Open the liquid chamber 12.7-ram (0.5-in.) valve. 20.4 If a dead-weight tester is used instead of the mercury manometer (See 16.2), apply the calibration factor in ldlopascals (pounds-force per square inch) established for the pressure gage to the uncorrected vapor pressure. Record this value as the calibrated gage reading and use in Section 7 in place of the manometer reading.

16. Apparatus

16.1 Apparatus as described in Annex A 1 using the liquid chamber with two openings. 16.2 Pressure Gage Calibration--A dead-weight tester (See A1.7) can be used in place of the mercury manometer (See A 1.6) for checking gage readings above 180 kPa (26 psi). In 6.1.1, 7.1, I 1.4, and 11.5.3 where the words manometer and manometer reading appear, include as an alternative dead-weight tester and calibrated gage reading respectively. 17. Hazards 17.1 The precaution in 6.1.6 shall not apply. 18. Sampling

18.1 Sections 9.3, 9.3.1, 9.4 and 9.5 shall not apply. 18.2 Sample Container Size--The size of the sample container from which the vapor pressure sample is taken shall not be less than 0.5 L (1 pt) liquid capacity.

PROCEDURE D FOR AVIATION GASOLINES APPROXIMATELY 50 kPa (7 psi) REID VAPOR PRESSURE

19. Preparation for Test

19.1 Sections 10.1 and 10.2 shall not apply. 19.2 Any safe method of displacement of the test sample from the sample container that ensures filling the liquid chamber with a chilled, unweathered sample may be employed. The following, 19.3 to 19.5, describe displacement by self-induced pressure. 19.3 Maintain the sample container at a temperature sufficiently high to maintain superatmosphedc pressure but not substantially over 37.8"C (100*F). 19.4 Completely immerse the liquid chamber, with both valves open, in the water cooling bath for a sufficient length of time to allow it to reach the bath temperature of 0 to 4.5"C (32 to 40*F). 19.5 Connect a suitable ice-cooled coil to the outlet valve of the sample container (See Note 10). NOTf 10--A suitableice-cooledcoil can be prepared by immersinga spiral of approximately8 m (25 ft) of 6.35-mm (0.25-in.) copper tubing in a bucket of ice water.

21. Introduction

21.1 The following sections define changes in apparatus and procedure for the determination of the vapor pressure of aviation gasoline. Except as specifically stated heredn, all the requirements set forth in Sections 1 to 11 shall apply. 22. Apparatus

22. I Ratio of Vapor and Liquid Chambers--The ratio of the volume of the vapor chamber to the volume of the liquid chamber shall be between the limits of 3.95 and 4.05 (See AI.I.4). 23. Sampling

23.1 Refer to Section 9. 24. Preparation for test

20. Procedure

24.1 Checking the Pressure Gage or Pressure TransducermThe gage shall be checked at 50 kPa (7 psi) against a

20.1 Sections 11.1 and 11.2 shall not apply. 20.2 Connect the 6.35-mm (0.25-in.) valve of the chilled liquid chamber to the ice-cooled coil. With the 12.7-ram (0.5

mercury column before each vapor pressure measurement to ensure that it conforms to the requirements of A I.2. This preliminary check shall be made in addition to the final gage 116

q~) D 323 comparison specified in 11.4 or 14.4.

26. Keywords

25. Procedure 25.1 Refer to Section 11.

26.1 crude oils; gasoline; Reid vapor pressure; sparkignition engine fuel; vapor pressure; volatility ANNEX ( M a n d a t o r y Information)

A1. APPARATUS FOR VAPOR PRESSURE TEST PROCEDURE A AI.1 Reid Vapor Pressure Apparatus, consisting of two chambers, a vapor chamber (upper section) and a liquid chamber (lower section), shall conform to the following requirements: A 1.1.1 Vapor Chamber--The upper section or chamber, as shown in Fig. A 1. I, shall be a cylindrical vessel having the inside dimensions of 51 ± 3 mm (2 + 1/8 in.) in diameter and 254 ± 3 mm (10 + l/s in.) in length, with the inner surfaces of the ends slightly sloped to provide complete drainage from either end when held in a vertical position. On one end of the vapor chamber, a suitable gage coupling with an internal diameter of not less than 4.7 mm (3/16 in.) shall be provided to receive the 6.35 mm (1/4 in.) gage connection. In the other end of the vapor chamber an opening approximately 12.7 mm (V2 in.) in diameter shall be provided for coupling with the liquid chamber. Care shall be taken that the connections to the openings do not prevent the chamber from draining completely. A1.1.2 Liquid Chamber--One Opening--The lower section or liquid chamber, as shown in Fig. A I.I, shall be a cylindrical vessel of the same inside diameter as the vapor ~--Couphng

E

,B

chamber and of such a volume that the ratio of the volume of the vapor chamber to the volume of the liquid chamber shall be between 3.8 and 4.2. (See AI.I.3). In one end of the liquid chamber an opening of approximately 12.7 mm (I/2 in.) in diameter shall be provided for coupling with the vapor chamber. The inner surface of the coupling end shall be sloped to provide complete drainage when inverted. The other end of the chamber shall be completely closed. NcyrE AI.I: Caution--To maintainthe correct volumeratio between the vaporchamberand the liquidchamber,paired chambersshall not be interchangedwithoutrecalibrationto ascertain that the volume ratio is within the required limits. Al.I.3 The ratio of paired vapor and liquid chambers to be used for aviation gasoline testing shall be between 3.95 to 4.05. AI. 1.4 Liquid Chamber--Two Openings--For sampling from dosed vessels the liquid section of liquid chamber, as shown in Fig. A 1.1 shall be essentially the same as the liquid chamber described in AI.I.2, except that a 6.35 mm (0.25 in.) valve shall be attached near the bottom of the liquid chamber and a 12.7 mm (0.5 in.) straight-through, fullopening valve shall be introduced in the coupling between the chambers. The volume of the liquid chamber, including only the capacity enclosed by the valves, shall fulfill the volume ratio requirements as set forth in AI.1.2. A I:1.5 In determining the capacities for the two-opening liquid chamber (Fig. A I.I) the capacity of the liquid chamber shall be considered as that below the 12.7 mm (0.5 in.) valve closure. The volume above the 12.7 mm (0.5 in.) valve closure including the portion of the coupling permanently attached to the liquid chamber shall be considered as a part of the vapor chamber capacity. AI.I.6 Method of Coupling Vapor and Liquid Chambers-Any method of coupling the vapor and liquid chambers can be employed, provided that no sample is lost from the liquid chamber during the coupling operation, that no compression effect is caused by the act of coupling, and that the assembly is free of leaks under the conditions of the tests. To avoid displacement of sample during assembly, the male fitting of the coupling must be on the liquid chamber. To avoid compression of air during assembly a vent hole must be present to ensure atmospheric pressure in the vapor chamber at the instant of sealing.

Couphng

r~F

Valve , Liqu0dChamber (Two Openings)

Vent

Hole H

Couphng

'~

Vapor Chamber

kiqu;d Chamber (One Opening)

DIMENSIONS OF VAPOR PRESSURE APPARATUS

Key A B,C,D E F,G H I J

Description Vapor chamber, length Vapor and gasoline chambers, Liquid ID Coupling, ID min Coupling, OD Coupling, ID Valve Valve FIG. A1.1

mm 254 :I: 3 51 + 3 4.7 12.7 12.7 12.7 6.35

in. 10 :I: I/8

NOTE AI.2: Caution--Some commerciallyavailable apparatus do not make adequate provision for avoiding air compression effects. Before employingany apparatus, it shall be established that the act of couplingthe two chambersdoes not compressair in the vapor chamber. This can be accomplishedby tightlystopperingthe liquid chamber and couplingthe apparatus in the normal manner, utilizinga 0 to 35 kPa (0

2 + 1/8

=As 1/= 1/= 1/= 1/4

to 5 psi) gage. Any observable pressure increase on the gage is an indication that the apparatus does not adequately meet the specifications

Vapor Pressure Apparatus

117

~ TABLE A1.1

D 323

Pressure G a g e Range and Graduations Gage to be Used

Reid Vapor Pressure

Maximum Numbered Intervals

Scale Range

Maximum Intermediate Graduations

kPa

psi

kPa

psi

kPa

psi

kPa

psi

_<27.5 20.0-75.0 70.0-180.0 70.0-250.0 200.0-375.0 _>350.0

<4 3-12 10-26 10-36 30-55 > 50

0-35 0-100 0-200 0-300 0-400 0-700

0-5 0-15 0-30 0-45 0-60 0-100

5.0 15.0 25.0 25.0 50.0 50.0

1 3 5 5 10 10

0.5 0.5 1.0 1.0 1.5 2.5

0.1 0.1 0.2 0.2 0.25 0.5

differs from the manometer reading, or dead-weight tester reading when testing gages above 180 kPa (26 psi), by more than 1% of the scale range of the gage, the gage shall be considered inaccurate. For example, the calibration correction shall not be greater than 0.3 kPa (0.15 psi) for a 0 to 30-kPa (0 to 15 psi-) gage or 0.9 kPa (0.3 psi) for a 0 to 90-kPa (0 to 30-psi) gage.

DEL I VERY TUBE STOPPER

NOTE A1.3--Gages 90 mm (3.5 in.) in diameter can be used in the 0 to 35 kPa (0 to 5 psi) range.

AI.3 Cooling Bath--A cooling bath shall be provided of such dimensions that the sample containers and the liquid chambers can be completely immersed. Means for maintaining the bath at a temperature of 0 to 1 (32 to 34°F) must be provided. Do not use solid carbon dioxide to cool samples in storage or in the preparation of the air saturation step. Carbon dioxide is appreciably soluble in gasoline and its use has been found to be the cause of erroneous vapor pressure data. A1.4 Water Bath--The water bath shall be of such dimensions that the vapor pressure apparatus can be immersed to at least 25.4 mm (1 in.) above the top of the vapor chamber. Means for maintaining the bath at a constant temperature of 37.8 + 0.1°C (100 + 0.2°F) shall be provided. In order to check this temperature the bath thermometer shall be immersed to the 37°C (98°1:) mark throughout the vapor pressure determination. A1.5 Thermometer--An ASTM Reid Vapor Pressure Thermometer 18C (181:) having a range from 34 to 42°C (94 to 1080F) and conforming to the requirements in Specification E 1. AI.6 Mercury Manometer--A mercury manometer having a range suitable for checking the pressure gage employed shall be used. The manometer scale shall be graduated in steps of 0.5 kPa, 1 mm, 0.1 in., or 0.1 psi. AI.7 Dead-Weight Tester--A dead-weight tester can be used in place of the mercury manometer (AI.5) for checking gage readings above 180 kPa (26 psi). AI.8 Sample Transfer Connection--This is a device for removing liquid from the sample container without interfeting with the vapor space. The device consists of two tubes inserted into a two-holed stopper of appropriate dimensions to fit the opening of the sample container. One of the tubes is short for the delivery of the sample, and the other is long enough to reach the bottom comer of the sample container. Fig A I.2 shows a suitable arrangement.

$ANPL I NG TUBE

FIG. A1.2

Sample Transfer Connection

of this test method. If this problem is encountered, consult the manufacturer for a remedy.

AI.1.7 VolumetricCapacity of Vapor and Liquid Chambers-To ascertain if the volume ratio of the chambers is within the specified limits of 3.8 to 4.2 (see A 1.1.3), carefully measure a quantity of water greater than will be required to fill the two chambers. (A dispensing buret is a convenient vessel for this operation.) Without spillage fill the liquid chamber completely. The difference between the original volume and the remaining volume of the measured water quantity is the volume of the liquid chamber. Without spillage couple the liquid and vapor chambers and fill the vapor chamber to the seat of the gage connection with more of the measured water. The difference between the final volume of the measured water quantity and the intermediate volume measured after ascertaining the liquid chamber volume is the volume of the vapor chamber. AI.2 Pressure Gage--The pressure gage shall be a Bourdon type spring gage of test gage quality I00 to 150 mm (4.5 to 6.5 in.) in diameter provided with a nominal 6.35 mm (0.25 in.) male thread connection with a passageway not less than 4.7 mm (3/16 in.) in diameter from the Bourdon tube to the atmosphere. The range and graduations of the pressure gage shall be governed by the vapor pressure of the sample being tested, in accordance with Table A I. 1. Only accurate gages shall be continued in use. When the gage reading

118

(I~) D 3 2 3

A2. APPARATUS FOR VAPOR PRESSURE TEST PROCEDURE B A2.1 VaporPressureApparatus--Refer to A 1.1.1 through Note AI.I and Al.l.6 through Al.l.7. A2.2 Pressure Gage--The pressure measuring system shall be a Bourdon type spring gage as described in AI.2 or a suitable pressure transducer and digital readout. The pressure measuring system shall be remotely mounted from the vapor pressure apparatus and terminations provided for use of a quick connection type fitting. A2.3 CoolingBath--Refer to Note AI. I. A2.4 Water Bath--The water bath shall bc of such dimensions that the vapor pressure apparatus can bc immersed in a horizontal position. Provision shall bc made to rotate the apparatus on its axis 350" in one direction and then 350" in the opposite direction in repetitive fashion. Means for maintaining the bath at a constant temperature of 37.8 ± 0.1°C (I00 ± 0.2°F) shall be provided. In order to

check this temperature, the bath thermometer shall be immersed to the 370C (98"F) mark throughout the vapor pressure determination. A suitable bath is shown in Fig. A2.1 and is available commercially. A2.5 Thermometers--Referto A 1.5. A2.6 MercuryManometer--Refer to AI.6. A2.7 Flexible Coupler--A suitable flexible coupling shall be provided for connection of the rotating vapor pressure apparatus to the pressure measuring device. A2.8 Vapor Chamber Tube--The vapor chamber tube of inner diameter 3 m m (I/sin.)and length of 114 m m (4.5 in.) shall bc inserted into the pressure measuring end of the vapor chamber to prevent liquid from entering the vapor pressure measuring connections. A2.9 Sample Transfer Connection--Refer to A 1.8.

vAPOR

ANALOGGAGEVERSION

~.......,,--'~"(~WBER

tocater8 (3)

Gale COUp1~l~8e

4 - ~ 114 Im

T

4

TO PRESSURE NEASUREHENT

u

"- \ ~ R

FIG. A2.2 Vapor Chamber Tube Inserted in Vapor Chamber

Iflextble Coupl~,al* Qvtck Coanecl; rttet~|lb

AIPFIrICu ( u x 3) Bath Contt'ol h t l ;

DIGITAL GAGEVERSION

/ /

....

430 mm

YZZV

FIG. A2.1

Apparatus for Vapor Pressure, Procedure B

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted m connection with any item menttoned in this standard Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every hve years and ff not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments w#l receive careful consideration at a meeting of the responsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you .should make your wews known to the ASTM Committee on Standards, 100 Barr Harbor Drive, West Conshohocken, PA 19428.

119

Designation: D 341 - 93 Standard Viscosity-Temperature

An American National Standard

Charts for Liquid Petroleum Products 1

This standard is issued under the fixed designation D 341; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (E) indicates an editorial change since the last revision or reapproval.

This standard has been approvedfor use by agencies of the Department of Defense to replace Method 9121 of Federal Test Method Standard No. 79lb. Consult the DoD Index of Specifications and Standards for the specific year of issue which has been adopted by the Department of Defense.

1. Scope I. 1 The kinematic viscosity-temperature charts 2 covered by this standard are a convenient means to ascertain the kinematic viscosity of a petroleum oil or liquid hydrocarbon at any temperature within a limited range, provided that the kinematic viscosities at two temperatures are known. 1.2 The charts are designed to permit petroleum oil kinematic viscosity-temperature data to plot as a straight line. The charts here presented provide a significant improvement in linearity over the charts previously available under Method D 341 - 4 3 . This increases the reliability of extrapolation to higher temperatures. 2. Technical Hazard 2.1 Caution--The charts should be used only in that range in which the hydrocarbon or petroleum fluids are homogeneous liquids. The suggested range is thus between the cloud point at low temperatures and the initial boiling point at higher temperatures. The charts provide improved linearity in both low kinematic viscosity and at temperatures up to 340"C (approximately 650"F) or higher. Some high-boiling point materials can show a small deviation from a straight line as low as 280"C (approximately 550"F), depending on the individual sample or accuracy of the data. Reliable data can be usefully plotted in the high temperature region even if it does exhibit some curvature. Extrapolations into such regions from lower temperatures will lack accuracy, however. Experimental data taken below the cloud point or temperature of crystal growth will generally not be of reliable repeatability for interpolation or extrapolation on the charts. It should also be emphasized that fluids other than hydrocarbons will usually not plot as a straight line on these charts. 3. Description 3.1 The charts are designed to permit kinematic viscositytemperature data for a petroleum oil or fraction, and hydrocarbons in general, to plot as a straight line over a wide range. Seven charts are available as follows: 3

Chart 1--Kinematic Viscosity, High Range: Kinematic Viscosity: 0.3 to 20 000 000 cSt Temperature: -70 to +370"C Size: 680 by 820 mm (26.75 by 32.25 in.) Pad of 50 PCN 12-403411-12 Chart II-- Kinematic Viscosity, Low Range: Kinematic Viscosity: 0.18 to 6.5 cSt Temperature: -70 to +370"C Size: 520 by 820 mm (20.5 by 32.25 in.) Pad of 50 PCN 12-403412-12 Chart IlI--Kinematic Viscosity, High Range: Kinematic Viscosity: 0.3 to 20 000 000 cSt Temperature: -70 to +370"C Size: 217 by 280 mm (8.5 by 11.0 in.) Pad of 50 PCN 12-403413-12 Chart IV--Kinematic Viscosity, Low Range: Kinematic Viscosity: 0.18 to 6.5 cSt Temperature: -70 to +3700C Size: 217 by 280 mm (8.5 to 11.0 in.) Pad of 50 PCN 12-403414-12 Chart V--Kinematic Viscosity, High Range." Kinematic Viscosity: 0.3 to 20 000 000 cSt Temperature: -100 to +700*F Size: 680 by 820 mm (26.75 by 32.25 in.) Pad of 50 PCN 12-403415-12 Chart VI--Kinematic Viscosity, Low Range: Kinematic Viscosity: 0.18 to 3.0 cSt Temperature: - 100 to +700*F Size: 520 by 820 mm (20.5 by 32.25 in.) Pad of 50 PCN 12-403416-12 Chart VII--Kinematic Viscosity, Middle Range: Kinematic Viscosity: 3 to 200 000 cSt Temperature: -40 to + 150"C Size: 217 by 280 mm (8.5 by 11.0 in.) Pad of 50 PCN 12-403417-12 3.2 Charts I, II, V, and VI are preferred when convenience and accuracy of plotting are desired. Chart VII is the middle range section of Chart I at somewhat reduced scale. It is provided for convenience in connection with reports and data evaluation. Charts III and IV are the same as Charts I and II and are provided in greatly reduced scale for convenience in connection with reports or quick evaluation of data. These latter charts are not recommended for use where the most accurate interpolations or extrapolations are desired.

STbesc charts are under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and are the direct responsibility of Subcommittee D02.07 on Flow Properties. Current edition approved March 15, 1993. Published May 1993. Originally published as D 341 - 32 T. Last previous edition D 341 - 89. 2 Facsimiles of two of the charts are given in Figs. 1 and 2. a The Viscosity-Temperature Charts are available from ASTM, 1916 Race St., Philadelphia, PA 19103. Charts V and VI are intended for use with viscometfic data based on Fahrenheit temperature. It is anticipated that these two charts will be deleted when the current stock is deleted. When ordering, refer to Publication Code Number (PCN).

4. Procedure 4.1 Plot two known kinematic viscosity-temperature 120

~

D 341

FIG. 1 Facsimile of Kinematic Viscosity-Temperature Chart I High Range (Temperature in degrees Celsius)

points on the chart. Draw a sharply defined straight line through them. A point on this line, within the range defined in Section 2, shows the kinematic viscosity at the corresponding desired temperature and vice versa. 4

temperature line is located quite accurately. For purposes of extrapolation, it is especially important that the two known kinematic viscosity-temperature points be far apart. If these two points are not sufficiently far apart, experimental errors in the kinematic viscosity determinations and in drawing the line may seriously affect the accuracy of extrapolated points, particularly if the difference between an extrapolated temperature and the nearest temperature of determination is greater than the difference between the two temperatures of determination. In extreme cases, an additional determination at a third temperature is advisable.

5. Extrapolation 5.1 Kinematic viscosity-temperature points on the extrapolated portion of the line, but still within the range defined in Section 2, are satisfactory provided the kinematic viscosity-

6. Keywords 6.1 charts; kinematic viscosity; MacCoull; viscosity; viscosity-temperature charts

4 if the kinematic viscosities are not known, they should be determined in accordance with Method D 445, Test for Kinematic Viscosity of Transparent and Opaque Liquids (and the Calculation of Dynamic Viscosity), Annual Book of ASTM Standards, Vol 05.01.

121

ii~) D 341 tctc,h ~ l r t j ~ ,

. . . . . . . . . . . . . . . . . . .

o(otv~lEI, ¢ELIIU~

~,..7,.',,,~, 2,~7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

FIG. 2 Facsimile of Kinematic Viscosity-Temperature Chart II Low Range (Temperature In degrees Celsius)

APPENDIXES

(NonmandatoryInformation) Xl.

MATHEMATICAL RELATIONSHIPS

X 1. I The charts were derived 5 with computer assistance to provide linearity over a greater range on the basis of the most reliable of modern data. The general relationship is: log log Z ffi A - B log T where: Z log v T A and B C D E F G H

(1)

natural base e since this simplifies computer programming. Equation 1 uses logarithms to the base 10 for g e n e r a l convenience when used in short form. X 1.1.2 The limits of applicability are listed below: Z = Z-Z-Z-Z--

ffi ( v + O . 7 + C - D + E - F + G - H ) , ---- logarithm to base 10, = kinematic viscosity, cSt (or mm2/s), -- temperature, K or *R, = constants, = exp (-1.14883 - 2.65868v), = exp ( - 0 . 0 0 3 8 1 3 8 - 12.5645v), = exp (5.46491 - 37.6289 v), = exp (13.0458 - 74.6851v), -- exp (37.4619 - 192.643v), and = exp (80.4945 - 400.468v).

(v + 0.7) (v+0.7+C) (v+0.7+C-D) (v+0.7+C-D+E) (v+O.7+C-D+E-F

2 x l 0 7 to 2.00 cSt 2xl07tol.65cSt 2x l07to0.90cSt 2x l07to0.30cSt 2 x 107to0.24cSt

+ G)

Z=

X I.I.1 Terms C through H are exponentials on the 5 Wright, W. A., "An Improved Viscosity-Temperature Chart for Hydrocarbons," Journal of Materials, Vol 4, No. I, 1969, pp. 19-27.

122

(v+O.7+C-D+E-F 2 x 107 to 0.21 cSt + G-H) X1.2 It is obvious that Eq 1 in the simplified form: log log (v + 0.7) -- A - B log T will permit kinematic viscosity calculations for a given fluid in the majority of instances required. The constants A and B can be evaluated for a fluid from two data points. Kinematic viscosities or temperatures -for other points can then be readily calculated. XI,3 Older literature refers to a value called the ASTM Slope, It should be noted that this value is not the value of B given in Eq I, The ASTM Slope was originally obtained by

D 341

(~

log log Z = A - B log T Z = =, + 0.7 + exp(-l.47 - 1.84~ - 0.51~ 2) = [Z - 0.7] - exp(-0.7487 - 3.295 [Z - 0.7]) + 0.6119 [Z - 0.7]2 - 0.3193 [Z - 0.7] 3)

physically measuring the slope of the kinematic viscositytemperature data plotted on the older charts given in Method D 341 - 43. The kinematic viscosity and temperature scales were not made to the same ratios in Method D 341 - 43. The improved charts given here utilize even different scale ratios for dimensional convenience and a different constant (0.7) from the older charts; consequently, the original ASTM Slope is not numerically equivalent to B in Eq 1 from any of the new charts, nor directly convertible from Eq 1. X 1.4 The complete design equation for the chart as given in X I.I is not useful for inter-calculations of kinematic viscosity and temperature over the full chart kinematic viscosity range. More convenient equations 6 which agree closely with the chart scale are given below. These are necessary when calculations involve kinematic viscosities smaller than 2.0 eSt.

where: log

u) I.iJ O p.(/) Z hi (,)

40

50

60

70

80

90

I O0

IZo

I I0

)))+++++++)))))+)+++

++)+++)++)+)+)+)))

50~., 400 300

500 400

3OO

200

Zoo

150

150

imn lmmm

mmmm

m

| mmmmmlm

mmllmmlmlm

; _- _-._- _- _. _. _. _-.| -_._. _- _- _-,_- _- _- -_ _-

I OO

I00 |m

n

n

i N mlmlmm m

q m i) ~

iN u

m

m im mlm

75

I.O ¢j @)

N

mmmmmm mmmm

mmmmm-,,m m m m m m m

mm

mmm

,...=ll.nllllnilll

50

50

[|_m|ltllllllBl.lllll IW--" II i • --

40

,..|IP.|.t|I.|.:.!H i=::.:mr.:=zu m:.:n:::mm=m

30

40 30

2O

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20

15

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15

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z

o=

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75

N

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=

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I0 90 80

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7.O

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lm

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IIIIBI,

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6.O 5.0 30

40

50

60

TEMPERATURE. FIG. X2.1

(4)

= logarithm to base 10, = kinematic viscosity, cSt (or mm2/s), = temperature, K or °R, and T A and B = constants. X 1.4.1 Inserting Eq 3 into Eq 2 will permit solving for the constants ,4 and B for a fluid in which some of the experimental kinematic viscosity data fall below 2.0 eSt. This form can also be used to calculate the temperature associated with a desired kinematic viscosity. X1.4.2 Conversely, the kinematic viscosity associated with a stated temperature can be found from the equation determined as in X 1.4. l by solving for Z in the substituted Eq 2, and then subsequently deriving the kinematic viscosity from the value of Z by the use of Eq 4. 1/

6 Manning, R. E., "Computational Aids for Kinematic Viscosity Conversions from 100 and 210°F to 40 and 100"C," Journal of Testing and Evaluation, JTEVA, Vol 2, No. 6, 1974 pp. 522-8.

30

(2) (3)

70 DEGREES,

80

90

CELSIUS

Oil Blending Calculations

123

I00

I10

120

7, o

,.=,

10 9.0 8.0 70 S,0 5.0

z

~) D 341 X2. OIL BLENDING CALCULATIONS X2.1 Predicting the volume fractions of two given oils when blending to meet a specified kinematic viscosity at a given temperature is a common problem. A number of blending calculation techniques have been used. The Wright method described here is preferred since it automatically allows for the effects of oil type, molecular weight and viscosity index of component oils. This results in greater accuracy, particularly where component oil kinematic viscosities or types differ significantly. X2.2 Two methods are given below: X2.2.1 A plotting technique on ASTM viscosity temperature charts. See X2.3. X2.2.2 Calculation on a pocket calculator (preferably a programmable calculator or a computer). See X2.4. X2.2.3 In either case, the required data are the kinematic viscosities of each component oil at 40 and 100*C and the desired kinematic viscosity of the oil blend at one of these temperatures. X2.3 Plot the known data for each component on an ASTM Viscosity-Temperature Chart and carefully draw straight lines through the points. The lines should extend beyond the blend kinematic viscosity required. Locate, or draw, the desired blend kinematic viscosity horizontal line on the chart through both of the component oil lines. Lay a centimetre scale along this line and carefully measure the distance between the lines for the two oils where they cross the line of the desired blend kinematic viscosity. Without moving the scale, on the same horizontal kinematic viscosity line read the distance from the low viscosity oil line to the temperature desired. Dividing the latter by the first measurement between the two oils gives the volume fraction needed for the high viscosity oil. X2.3.1 An example of the above method is as follows: Given:

low viscosity oil high viscosity oil

~(4o-c) Vooo.c} v(4o-O Uooo. 0

volume fraction of the high viscosity oil is as follows: Volume fraction (high kinematic viscosity) = 3.-3-0 2.26 = 0.685 X2.4 The required blend may also be calculated using a calculator or computer. The relationships are at 40"C: volume fraction high viscosity oil =

[ (EA) (C- D) ]-' ~-~= - ~ ~-~~ C) + 1

at 100*C: volume fraction high viscosity oil = [ (F(E: ~ ' ~B-) ( C - D) +D) 1 ]-' where: Subscripts: A -- log log ZBt4o) B = log log Za(too) B -- blend C = log log ZL(40) L = low-viscosity oil H = high viscosity oil D = log log ZLtl00) (40) = 40°C E = log log ZH(40) F = log log ZHO00) (100) = 100*C Z = (cSt + 0.70) X2.4.1 An example of this second method using the data in X2.3.1 is as follows: s = 0.05565 E = 0.358O0 C = 0.24336 D = -0.03914

F = 0.09621

Volume fraction high viscosity oil at 100°C = [(0.09621-0.05565)(0.24336+0.03914) ]-t (0.35800 0.09621)(0.05565 + 0.03914) + I -- 0.684 X2.5 It may be noted that the same general methods of calculation can be adapted for use with other temperatures. If the kinematic viscosity-temperature data must be extrapolated to temperatures far above or below the data, the accuracy of the calculation may be significantly lessened. X2.6 The oil blending calculations can be done more conveniently by computer. One program in BASIC that is convenient to use has been published. 7

= 55.7 cSt = 7.50 eSt = 190.00 cSt ,= 17.00 eSt

Determine: Volume fraction of the high viscosity oil for a blend of 13.00 cSt at 100*C. Figure X2.1 is a segment of Chart VII. From Fig. X2.1, the distance from the low viscosity oil to 100*C along the 13.0cSt line is 2.26 cm. The distance from the low viscosity oil to the high viscosity oil along the 13.0-cSt line is 3.30 cm. The

7 Huggins, P., "Program Evaluates Component and Blend Viscosities," Oil and Gas Journal, Voi 83, No. 43, 1985, pp. 122-129. Copies of a similar program derived from this program are available from Cannon Instrument Company, P. O. Box 16, State College, PA 16804-0016.

X3. HISTORY OF THE ASTM VISCOSITY-TEMPERATURE CHARTS X3.1 The forerunner of these charts was published by Neil MacCoull s. His continuation of the study of these charts resulted in publication in 19279 of the chart based on log log(cSt + 0.7) = A - B log T

An ASTM committee undertook study of this chart at that time, resulting in the first ASTM chart publication in 1932 using a constant of 0.8 in the equation. The constant was allowed to vary in charts published after 1937. X3.2 Walther published in 1928 the log-log equation (5) without the constant and in 1931 the log-log equation with a constant of 0.8. X3.3 The present MacCoull-Wright charts are based largely on the work of MacCoull, Wright, 5 and ASTM Subcommittee D02.7.

(5)

s MacCoull, N., Lubrication, The Texas Company, New York, June 1921, p. 65.

9 1927 International Critical Tables, p. 147.

124

~

D 341

The American Society for Testing and Materials takes no position respecting the vahdlty of any patent rights asserted m connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibdity. This standard is Sublect to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments wit/receive careful consideration at a meeting of the responsible technical committee, which you may attend. /f you fee/that your comments have not received a fair hearing you .should make your views known to the ASTM Committee on Standards, 100 Barr Harbor Drive, West Conshohocken, PA 19428.

125

Designation: D 445 - 96

:~',;:,~:~,,~,,,,

An American National Standard Bdtish Standard 2000: Part 71:1990

Designation: 71195 Standard Test Method for

Kinematic Viscosity of Transparent and Opaque Liquids (the Calculation of Dynamic Viscosity) 1 This standard is issued under the fixed designation D 445; the number immediately following the designation indicates the year of original adoption or, in the ease of revision, the year of last revision. A number in parentheses indicates the year of last re.approval. A superscript epsilon (¢) indicates an editorial change since the last revision or reapproval.

This test method has been approved by the sponsoring committee and accepted by the Cooperating Societies in accordance with established procedures. This standard has been approvedfor use by agencies of the Department of Defense and replaces Method 305.6 of Federal Test Method Standard 791b. Consult the DoD Index of Specifications and Standards for the specific year of issue which has been adopted by the Department of Defense.

D 446 Specifications and Operating Instructions for Glass Capillary Kinematic Viscometers2 D 1193 Specification for Reagent Water 3 D 1217 Test Method for Density and Relative Density (Specific Gravity) of Liquids by Bingham Pycnometer 2 D 1480 Test Method for Density and Relative Density (Specific Gravity) of Viscous Materials by Bingham Pycnometer 2 D 1481 Test Method for Density and Relative Density (Specific Gravity) of Viscous Materials by Lipkin Bicapillary Pycnometer 2 D 2170 Test Method for Kinematic Viscosity of Asphalts (Bitumens) + D 2171 Test Method for Viscosity of Asphalts by Vacuum Capillary Viscometer+ E 1 Specification for ASTM Thermometers 5 E 77 Test Method for the Inspection and Verification of Thermometers 5 2.2 ISO Standards: ~ ISO Guide 25--General Requirements for the Calibration and Testing Laboratories ISO 3104 Petroleum Products--Transparent and Opaque Liquids--Determination of Kinematic Viscosity and Calculation of Dynamic Viscosity ISO 3105 Glass Capillary Kinematic Viseometers--Specification and Operating Instructions ISO 3696 Water for Analytical Laboratory Use--Specification and Test Methods ISO 9000 Quality Management and Quality Assurance Standards--Guidelines for Selection and Use

1. Scope 1.1 This test method specifies a procedure for the determination of the kinematic viscosity, v, of liquid petroleum products, both transparent and opaque, by measuring the time for a volume of liquid to flow under gravity through a calibrated glass capillary viscometer. The dynamic viscosity, 71, can be obtained by multiplying the kinematic viscosity, v, by the density, p, of the liquid. NOTE l--For the measurement of the kinematic viscosity and viscosityof bituraens, see also Test Methods D 2170 and D 2171. 1.2 The result obtained from this test method is dependent upon the behavior of the sample and is intended for application to liquids for which primarily the shear stress and shear rates are proportional (Newtonian flow behavior). If, however, the viscosity varies significantly with the rate of shear, different results may be obtained from viscometers of different capillary diameters. The procedure and precision values for residual fuel oils, which under some conditions exhibit non-Newtonian behavior, have been included. 1.3 The range of kinematic viscosities covered by this test method is from 0.2 to 300 000 mm2/s (see Table A 1.1) at all temperatures (see 6.3 and 6.4). The precision has only been determined for those materials, kinematic viscosity ranges and temperatures as shown in the footnotes to the precision section. 1.4 The values stated in SI units are to be regarded as the standard. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

3. Terminology 3.1 Definitions of Terms Specific to This Standard: 3.1.1 density, n--the mass per unit volume of a substance at a given temperature. 3.1.2 dynamic viscosity, n--the ratio between the applied shear stress and rate of shear of a liquid.

2. Referenced Documents

2.1 A S T M Standards: ' This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.07 on Flow Properties. Current edition approved Nov. 10, 1996. Published January 1997. Originally published as D 445 - 37T. Last previous edition D 445 - 94 +t. In the IP, this test method is under the jurisdiction of the Standardization Committee.

2 Annual Book of ASTM 3 Annual Book of ASTM 4 Annual Book of ASTM s Annual Book of ASTM

Standards, Standards, Standards, Standards,

Voi 05.01. Vol I 1.01. eel 04.03. Vol 14.03. 6 Available from American National Standards Institute, 11 W. 42nd St., 13th Floor, New York, NY 10036.

126

D 445 D [ S < : : : u s s l o N l--It is sometimes called the coefficient of dynamic viscosity or, simply, viscosity.Thus dynamic viscosityis a measure of the resistanceto flow or deformationof a liquid. DiscussioN--The term dynamic viscosity can also be used in a different context to denote a frequency-dependentquantity in which shear stress and shear rate have a sinusodialtime dependence.

r~

r ~

I

I

I

I

3.1.3 kinematic viscosity, n--the resistance to flow of a fluid under gravity.

I

I

I

I

I

(a)

DLSCUSSmN--Forgravity flow under a given hydrostatichead, the pressure head of a liquid is proportional to its density, p. For any particular viscometer, the time of flow of a fixed volume of fluid is directlyproportionalto its kinematicviscosity,v, where p = ,71p,and ~ is the dynamicviscositycoefficient.

m-¢ !

r E

4. S u m m a r y o f Test M e t h o d

4. l The time is measured for a fixed volume of liquid to flow under gravity through the capillary of a calibrated viscometer under a reproducible driving head and at a closely controlled and known temperature. The kinematic viscosity is the product of the measured flow time and the calibration constant of the viscometer.

I I l

-J J

-I"

G

.J

5. Significance and U s e

5.1 Many petroleum products, and some non-petroleum materials, are used as lubricants, and the correct operation of the equipment depends upon the appropriate viscosity of the liquid being used. In addition, the viscosity of many petroleum fuels is important for the estimation of optimum storage, handling, and operational conditions. Thus, the accurate determination of viscosity is essential to many product specifications.

(b)

~mE

~C ._..=

................................

.-~m .L~--~--~

d I J

6. Apparatus

i

6.1 Viscometers--Use only calibrated viscometers of the glass capillary type, capable of being used to determine kinematic viscosity within the limits of the precision given in the precision section. 6.1.1 Viscometers listed in Table A1. l, whose specifications meet those given in Specification D 446 and in ISO 3105 meet these requirements. It is not intended to restrict this test method to the use of only those viscometers listed in Table Al.1. Annex Al gives further guidance. 6.1.2 Automation--Automated viscometers, which have been shown to determine kinematic viscosity within the limits of precision given in Section 16 are acceptable alternatives. Apply a kinetic energy correction (see Specification D 446 and ISO 3105) to kinematic viscosities less than l0 mm2/s and flow times less than 200 s. 6.2 Viscometer Holders--Use viscometer holders to enable all viscometers which have the upper meniscus directly above the lower meniscus to be suspended vertically within l ° in all directions. Those viscometers whose upper meniscus is offset from directly above the lower meniscus shall be suspended vertically within 0.3" in all directions (see Specification D 446 and ISO 3105). 6.2.1 Viscometers shall be mounted in the constant temperature bath in the same manner as when calibrated and stated on the certificate of calibration. See Specifications D 446, see Operating Instructions in Annexes A l, A2, and A3. For those viscometers which have Tube L (see Specifications D 446) held vertical, vertical alignment shall be con-

~

,i

'

E5

,

(c) FIG. 1 ThermometerDesigns

firmed by using (1) a holder ensured to hold Tube L vertical, or (2) a bubble level mounted on a rod designed to fit into Tube L, or (3) a plumb line suspended from the center of Tube L, or (4) other internal means of support provided in the constant temperature bath. 6.3 Temperature-Controlled Bath--Use a transparent liquid bath of sufficient depth such, that at no time during the measurement of flow time, any portion of the sample in the viscometer is less than 20 mm below the surface of the bath liquid or less than 20 mm above the bottom of the bath. 6.3.1 Temperature Control--For each series of flow time measurements, the temperature control of the bath liquid shall be such that within the range from 15 to 100°C, the temperature of the bath medium does not vary by more than -+0.02°C of the selected temperature, over the length of the viscometer, or between the position of each viscometer, or at the location of the thermometer. For temperatures outside this range, the deviation from the desired temperature must not exceed _+0.05°C.

6.4 Temperature Measuring Device in the Range from 0 to lO0°C--Use either calibrated liquid-in-glass thermometers (Annex A2) of an accuracy after correction of ±0.02°C or 127

~

D 445

better, or any other thermometric device of equal or better accuracy. 6.4.1 If calibrated liquid-in-glass thermometers are used, the use of two thermometers is recommended. The two thermometers shall agree within 0.04"C. 6.4.2 Outside the range from 0 to 100*C, calibrated liquid-in-glass thermometers of an accuracy after correction of +0.05"C or better shall be used, and when two thermometers are used in the same bath they shall agree within +0. I*C. 6.5 Timing DevicemUse any timing device that is capable of taking readings with a discrimination of 0.1 s or better, and has an accuracy within +0.07 % (see Annex A3) of the reading when tested over intervals of 200 and 900 s. 6.5.1 Electrical timing devices may be used if the current frequency is controlled to an accuracy of 0.05 % or better. Alternating currents, as provided by some public power systems, are intermittently rather than continuously controlled. When used to actuate electrical timing devices, such control can cause large errors in kinematic viscosity flow time measurements.

7. Reagents and Materials 7.1 Chromic Acid Cleaning Solution, or a nonchromiumcontaining, strongly oxidizing acid cleaning solution. NOTe 2: Warning--Chromic acid is a health hazard. It is toxic, a recognized carcinogen, highly corrosive, and potentially hazardous in contact with organic materials. If used, wear a full face-shield and full-length protective clothing including suitable gloves. Avoid breathing vapor. Dispose of used chromic acid carefully as it remains hazardous. Nonchromium-containing, strongly oxidizing acid cleaning solutions are also highly corrosive and potentially hazardous in contact with organic materials, but do not contain chromium which has special disposal problems.

7.2 Sample Solvent, completely miscible with the sample. Filter before use. 7.2.1 For most samples a volatile petroleum spirit or naphtha is suitable. For residual fuels, a prewash with an aromatic solvent such as toluene or xylene may be necessary to remove asphaltenic material. 7.3 Drying Solvent, a volatile solvent miscible with the sample solvent (7.2) and water (7.4). Filter before use. 7.3.1 Acetone is suitable. 7.4 Water, deionized or distilled and conforming to Specification D 1193 or Grade 3 oflSO 3696. Filter before use.

8. Calibration and Verification 8.1 ViscometersDUse only calibrated viscometers, thermometers, and timers as described in Section 6. 8.2 Certified Viscosity Reference Standards 7 (Table A2)D These are for use as confirmatory checks on the procedure in the laboratory. 8.2.1 If the determined kinematic viscosity does not agree within __.0.35 % of the certified value, recheck each step in the procedure, including thermometer and viscometer calibration, to locate the source of error. Annex A 1 gives details of standards available. 7 The ASTM Viscosity Oil Standards are available in I-pt (0.47 L) containers. Purchase orders should be addressed to the Cannon Instrument Co., P.O. Box 16, State College, PA 16804. Shipment will be made as specified or by best means.

8.2.2 The most common sources of error are caused by particles of dust lodged in the capillary bore and temperature measurement errors. It must be appreciated that a correct result obtained on a standard oil does not preclude the possibility of a counterbalancing combination of the possible sources of error. 8.3 The calibration constant, C, is dependent upon the gravitational acceleration at the place of calibration and this must, therefore, be supplied by the standardization laboratory together with the instrument constant. Where the acceleration of gravity, g, differs by more that 0. 1%, correct the calibration constant as follows: C2 ffi (g2/gl) X C, (l) where the subscripts 1 and 2 indicate, respectively, the standardization laboratory and the testing laboratory. 9. General Procedure for Kinematic Viscosity 9.1 Adjust and maintain the viscometer bath at the required test temperature within the limits given in 6.3.1 taking account of the conditions given in Annex A2 and of the corrections supplied on the certificates of calibration for the thermometers. 9.1.1 Thermometers shall be held in an upright position under the same conditions of immersion as when calibrated. 9.1.2 In order to obtain the most reliable temperature measurement, it is recommended that two thermometers with valid calibration certificates be used (see 6.4). 9.1.3 They should be viewed with a lens assembly giving approximately five times magnification and be arranged to eliminate parallax errors. 9.2 Select a clean, dry, calibrated viseometer having a range covering the estimated kinematic viscosity (that is, a wide capillary for a very viscous liquid and a narrower capillary for a more fluid liquid). The flow time shall not be less than 200 s or the longer time noted in Specification D 446. 9.2.1 The specific details of operation vary for the different types of viscometers listed in Table A 1. The operating instructions for the different types of viscometers are given in Specifications D 446. 9.2.2 When the test temperature is below the dew point, affix loosely packed drying tubes to the open ends of the viscometer. The drying tubes must fit the design of the viscometer and not restrict the flow of the sample by pressures created in the instrument. Carefully flush the moist room air from the viscometer by applying vacuum to one of the drying tubes. Finally, before placing the viscometer in the bath, draw up the sample into the working capillary and timing bulb and allow to drain back as an additional safeguard against moisture condensing or freezing on the walls. 9.2.3 Viscometers used for silicone fluids, fluorocarbons, and other liquids which are difficult to remove by the use of a cleaning agent, shall be reserved for the exclusive use of those fluids except during their calibration. Subject such viscometers to calibration checks at frequent intervals. The solvent washings from these viscometers shall not be used for the cleaning of other viscometers.

10. Procedure for Transparent Liquids 10.1 Charge the viscometer in the manner dictated by the 128

~

D 445 1 I. 1.2 Heat in the original container, in an oven, at 60 + 2"C for 1 h. 11.1.3 Thoroughly stir the sample with a suitable rod of sufficient length to reach the bottom of the container. Continue stirring until there is no sludge or wax adhering to the rod. 11.1.4 Recap the container tightly and shake vigorously for 1 min to complete the mixing. 11.1.4.1 With samples of a very waxy nature or oils of high kinematic viscosity, it may be necessary to increase the heating temperature above 60"C to achieve proper mixing. The sample should be sufficiently fluid for ease of stirring and shaking. 11.2 Immediately after completing 11.1.4, pour sufficient sample to fill two viscometers into a 100-mL glass flask and loosely stopper. 11.2.1 Immerse the flask in a bath of boiling water for 30 min. NOTE 3: Precaution--Exercise care as vigorous boil-over can occur when opaque liquids which contain high levels of water are heated to high temperatures.

design of the instrument, this operation being in conformity with that employed when the instrument was calibrated. If the sample contains solid particles, filter during charging through a (75-1xm) filter (see Specifications D 446). 10.1.1 In general, the viscometers used for transparent liquids are of the type listed in Table A 1.1, A and B. 10.1.2 With certain products which exhibit gel-like behavior, exercise care that flow time measurements are made at sufficiently high temperatures for such materials to flow freely, so that similar kinematic viscosity results are obtained in viscometers of different capillary diameters. 10.1.3 Allow the charged viscometer to remain in the bath long enough to reach the test temperature. Where one bath is used to accommodate several viscometers, never add or withdraw a viscometer while any other viscometer is in use for measuring a flow time. 10.1.4 Because this rime will vary for different instruments, for different temperatures, and for different kinemarie viscosities, establish a safe equilibrium rime by trial. 10.1.4.1 Thirty minutes should be sufficient except for the highest kinematic viscosities. 10.1.5 Where the design of the viscometer requires it, adjust the volume of the sample to the mark after the sample has reached temperature equilibrium. 10.2 Use suction (if the sample contains no volatile constituents) or pressure to adjust the head level of the test sample to a position in the capillary arm of the instrument about 7 mm above the first timing mark, unless any other value is stated in the operating instructions for the viscometer. With the sample flowing freely, measure, in seconds to within 0.1 s, the time required for the meniscus to pass from the first to the second timing mark. If this flow time is less than the specified minimum (see 9.2), select a viscometer with a capillary of smaller diameter and repeat the operation. 10.2.1 Repeat the procedure described in 10.2 to make a second measurement of flow time. Record both measurements. 10.2.2 If the two determinations of kinematic viscosity, calculated from the flow time measurements, agree within the stated determinability figure (see 16.1) for the product, use the average of these determinations to calculate the kinematic viscosity result to be reported. Record the result. If the determinations of kinematic viscosity do not agree within the stated determinability, repeat the measurements of flow times after thorough cleaning and drying of the viscometers and filtering (where required, see 10.1) of the sample. If the material or temperature, or both, is not listed in 16.1, for temperatures between 15 and 100*C use as an estimate of the determinability 0.20 %, and 0.35 % for temperatures outside this range.

11.2.2 Remove the flask from the bath, stopper tightly, and shake for 60 s. 11.3 Charge two viscometers in the manner dictated by the design of the instrument. For example, for the cross-arm or the BS U-tube viscometers for opaque liquids, filter the sample through a 75-1xm filter into two viscometers previously placed in the bath. For samples subjected to heat treatment, use a preheated filter to prevent the sample coagulating during the filtration. 11.3.1 Viscometers which are charged before being inserted into the bath may need to be preheated in an oven prior to charging the sample. This is to ensure that the sample will not be cooled below test temperature. 11.3.2 After 10 min, adjust the volume of the sample (where the design of the viscometer requires) to coincide with the f'filing marks as in the viscometer specifications (see Specifications D 446). 11.3.2 Allow the charged viscometers enough time to reach the test temperature (see 11.3.1). Where one bath is used to accommodate several viscometers, never add or withdraw a viscometer while any other viscometer is in use for measuring flow time. 11.4 With the sample flowing freely, measure in seconds to within 0.1 s, the time required for the advancing ring of contact to pass from the first timing mark to the second. Record the measurement. 11.4.1 In the case of samples requiting heat treatment described in 11.1 through 11.2.1, complete the measurements of flow time within 1 h of completing 11.2.2. Record the measured flow times. 11.5 Calculate kinematic viscosity, v, in mm2/s, from each measured flow time. 11.5.1 For residual fuel oils, if the two determinations of kinematic viscosity agree within the stated determinability figure (see 16.1), use the average of these determinations to calculate the kinematic viscosity result to be reported. Record the result. If the calculated kinematic viscosities do not agree, repeat the measurements of flow times after thorough cleaning and drying of the viscometers and filtering of the sample. If the material or temperature, or both, is not

11. Procedure for Opaque Liquids 11.1 For steam-refined cylinder oils and black lubricating oils, proceed to 11.3 ensuring a thoroughly representative sample is used. The kinematic viscosity of residual fuel oils and similar.waxy products can be affected by the previous thermal history and the following procedure described in 11.1.1 to 11.2.2 shall be followed to minimize this. 11.1.1 In general, the viscometers used for opaque liquids are of the reverse-flow type listed in Table A I. 1, C.

129

lip D 445 15.1.4 Any deviation, by agreement or otherwise, from the procedure specified, 15.1.5 Date of the test, and 15.1.6 Name and address of the test laboratory.

listed in 16.1, for temperatures between 15 and 100*C use as an estimate of the determinability 1.0 %, and 1.5 % for temperatures outside this range; it must be realized that these materials can be non-Newtonian, and can contain solids which can come out of solution as the flow time is being measured. 11.5.2 For other opaque liquids, no precision data is available.

16. Precision 16.1 Determinability (d)--The difference between successive determinations obtained by the same operator in the same laboratory using the same apparatus for a series of operations leading to a single result, would in the long run, in the normal and correct operation of this test method, exceed the values indicated only in one case in twenty: os

12. Cleaning of Viscometer 12.1 Between successive determinations of kinematic viscosity, clean the viscometer thoroughly by several rinsings with the sample solvent, followed by the drying solvent (see 7.3). Dry the tube by passing a slow stream of filtered dry air through the viscometer for 2 rain or until the last trace of solvent is removed. 12.2 Periodically clean the viscometer with the cleaning solution (Warning--see 7.1), for several hours to remove residual traces of organic deposits, rinse thoroughly with water (7.4) and drying solvent (7.3), and dry with filtered dry air or a vacuum line. Remove any inorganic deposits by hydrochloric acid treatment before the use of cleaning acid, particularly if the presence of barium salts is suspected.

Base oils at 40 and 100"Cs Formulated oils at 40 and 100°C9 Formulated oils at 150'C t° Petroleum wax at 100"C H Residual fuel oils at 80 and 100"C ~2 Residual fuel oils at 50"C 12

0.0020 y 0.0013 y 0.015 y 0.0080 y 0.011 (y+8) 0.017 y

(0.20 %) (0.13 %) (i.5 %) (0.80 %) (1.7 %)

where: y is the average of determinations being compared. 16.2 Repeatability (r)--The difference between successive results obtained by the same operator in the same laboratory with the same apparatus under constant operating conditions on identical test material would, in the long run, in the normal and correct operation of this test method, exceed the values indicated only in one case in twenty:

NOTE 4: Caution--It is essential that alkalinecleaning solutionsare not used as changesin the viscometercalibrationcan occur.

13. Calculation 13.1 Calculate the kinematic viscosity, v, from the measured flow time, t, and the viscometer constant, C, by means of the following equation: v = C.t (2) where: v = kinematic viscosity, mm2/s, C = calibration constant of the viscometer, (mm2/s)/s, and t = mean flow time, s. 13.2 Calculate the dynamic viscosity, n, from the calculated kinematic viscosity, v, and the density, p, by means of the following equation: 7/ ---- v X p X 10 - 3 (3)

Base oils at 40 and 100"(2s Formulated oils at 40 and 100"C9 Formulated oils at 150"C'°

0.0011 x 0.0026 x 0.0056 x

Petroleum wax at 100"C t' Residual fuel oils at 80 and 100"C '2

0.0141 x 1.2 0.013 (x+8)

Residual oils at 50"C t2

0.015 x

(0.11%) (0.26 %) (0.56 %) (I.5 %)

where: x is the average of results being compared. 16.3 Reproducibility (R)--The difference between two single and independent results obtained by different operators working in different laboratories on nominally identical test material would, in the long run, in the normal and correct operation of this test method, exceed the values indicated below only in one case in twenty. Base oils at 40 and 100"Cs Formulated oils at 40 and 100"C9 Formulated oils at 150"(2to Petroleum wax at 100"(211 Residual fuel oils at 80 and 100"C 12 Residual oils at 50°C 12

where: ,1 = dynamic viscosity, mPa.s, p -- density, kg/m 3, at the same temperature used for the determination of the kinematic viscosity, and v = kinematic viscosity, mm2/s. 13.2.1 The density of the sample can be determined at the test temperature of the kinematic viscosity determination by an appropriate method such as Test Methods D 1217, D 1480, or D 1481.

0.0065 x 0.0076 x 0.018 x 0.0366 x*.2 0.04 (x+8) 0.074 x

(0.65 %) (0.76 %) (1.8 %) (7.4 %)

°These precision values were obtained by statistical examination of inteflabomtory results from six mineral oils (base oils without additive package) in the range from 8 to 1005 mm2/s at 40"C and from 2 to 43 mm2/s at 100"C, and were first published in 1989. Precision data available from ASTM Headquarters. Request RR:D02-1331 and RR:D02-1132. 9These precision values were obtained by statistical examination of interlabomtory results from seven fully formulated engine oils in the range from 36 to 340 m m ' / s at 40"(2 and from 6 to 25 mm2/s at 100'C, and were first published in 1991. Precision data available from ASTM Headquarters. Request RR:D021332. m These precision values were obtained by statistical examination of interlaboratory results for eight fully formulated engine oils in the range from 7 to 19 mm2/s at 150"C, and first published in 1991. Precision data available from ASTM Headquarters. Request RR:D02-1333. t~ These precision values were obtained by statistical examination of interlaboratory results from five petroleum waxes in the range from 3 to 16 mm2/s at 100"C, and were first published in 1988. Precision data available from ASTM Headquarters. Request RR:D02-1334. '2These precision values were obtained by statistical examination of interlabomtory results from fourteen residual fuel oils in the range from 30 to 1300 m m ' / s at 50"C and from 5 to 170 m m ' / s at 80 and 100"C, and were first published in 1984. Precision data available from ASTM Headquarters. Request RR:D021198.

14. Expression of Results 14.1 Report the test results for the kinematic or dynamic viscosity, or both, to four significant figures, together with the test temperature. 15. Report 15.1 Report the following information: 15.1.1 Type and identification of the product tested, 15.1.2 Reference to this test method or a corresponding international standard, 15.1.3 Result of the test (see 14), 130

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D 445

where: x is the average of results being compared. 16.4 The precision for used oils has not been determined but is expected to be poorer than that for formulated oils. Because of the extreme variability of such used oils, it is not anticipated that the precision of used oils will be determined.

17. Keywords 17.1 dynamic viscosity; kinematic viscosity; viscometer; viscosity

ANNEXES

(Mandatory Information) AI. VISCOMETER TYPES, CALIBRATION, AND VERIFICATION AI.1 Viscometer Types AI.I.I Table AI.I lists capillary viscometers commonly in use for viscosity determinations on petroleum products. For specifications and operating instructions, refer to Specifications D 446.

viscometers or master viscometers, or by the procedures given in Specifications D446 or ISO 3105. Viscometer constants shall be measured and expressed to the nearest 0. 1% of their value. A1.3 Verification A I.3. l Viscometer constants shall either be vedfied by a similar procedure to AI.2, or conveniently checked by means of certified viscosity oils. AI.3.2 These oils can be used for confirmatory checks on the procedure in a laboratory. If the measured viscosity does not agree within +0.35 % of the certified value, recheck each step in the procedure including thermometer, timer, and viscometer calibration to locate the source of error. It should be appreciated that a correct result obtained on a certified oil does not preclude the possibility of a counterbalancing combination of the possible sources of error. AI.3.2.1 A range of viscosity oil standards is commercially available, and each oil carries a certification of the measured value established by multiple testing. Table AI.2 gives the standard range of oils, together with the approximate viscosities over a range of temperatures.

A1.2 Calibration A I.2.1 Calibrate working standard viscometers against master viscometers having a certificate of calibration traceable to a national standard. Viscometers used for analysis shall be calibrated in comparison with working standard T A B L E A1.1

Vlscometar Identification

Viscometer Types

Kinematic Viscosity Range,A mrrF/s

A. Ostwald Types for Transparent Uquids Cannon-Fenske routinea Zeitfuchs BS/U-tube '= BS/U/M miniature SIL a Cannon-Manning semi-micro Pinkevitch"

0.5 0.6 0.9 0.2 0.6 0.4 0.6

to to to to to to to

20 000 3 000 10000 100 10000 20 000 17000

B. Suspended-ievel Types for Transparent Liquids BS/IP/SL a BS/IP/SI-(S) e BS/IP/MSL UbbelohdeB RtzSlmons Atlantic a CannondJbbelohde(A), CannonUbbalohde dilution e(B) Cannon-Ubbelohde semi-micro

3.6 to 1.05 to 0.6 to 0.3 to 0,6 to 0.75 to 0.5 to

100 000 10000 3 000 100 000 1 200 5 000 100 000

TABLE A1.2

Designation -40°C S3 $6 $20 S60 $200 68oo 62000 68000 630000

0.4 to 20 000

C. Revarse-flow Types for Transparent and Opaque Liquids Cannon-Fenske opaque Zsiffuchs cross-arm BS/IP/RF U-tube reverse-flow Lantz-Zaltfuchs type reverse-flow

0.4 0.6 0.6 60

to to to to

20 000 100 000 300 000 100 000

Each range quoted requires a series of viscometers. To avoid the necessity of making a kinetic energy correction, these viscometars are designed for a flow time in excess of 200 s except where noted in Specifications D 446. B In each of these series, the minimum flow time for the viscometars with lowest constants exceeds 200 s.

Viscosity 011 S t a n d a r d s A

Approximate Kinematic Viscosity, mm=/s

80 ... ... ,.. ... ... ... ... ......

20°C

25°C

4&C

50°C

4.6 11 44 170 640 24oo 6700 37000

4.0 8.9 34 120 450 16oo 5600 2aooo 91000

2.9 5.7 16 54 180 620 1700 6700

... ... ... ...

2a00o

10&C

~8o ...

1.2 1.8 3.9 7.2 17 32 75

i~'ooo

iii

A The actual values for these standards are established and annually reaffirmed by cooperative tests. In 1991, tests were made using 15 different types of viscometers in 28 laboratories located in 14 countries, a Kinematic viscosities may also be supplied at 100°F, c Kinematic viscosities may also be supplied at 21&F.

131

q~) D 445 A2. KINEMATIC VISCOSITY TEST THERMOMETERS A2.2.3.1 Unless otherwise listed on the certificate of calibration, the re-calibration of calibrated kinematic viscosity thermometers requires that the ice-point reading shall be taken within 60 min after being at test temperature for not less than 3 min. A2.2.3.2 Select clear pieces of ice, preferably made from distilled or pure water. Discard any cloudy or unsound portions. Rinse the ice with distilled water and shave or crush into small pieces, avoiding direct contact with the hands or any chemically unclean objects. Fill the Dewar vessel with the crushed ice and add sufficient water to form a slush, but not enough to float the ice. As the ice melts, drain off some of the water and add more crushed ice. Insert the thermometer, and pack the ice gently about the stem, to a depth approximately one scale division below the 0*C graduation. A2.2.3.3 After at least 3 min have elapsed, tap the thermometer gently and repeatedly at fight angles to its axis while making observations. Successive readings taken at least l rain apart shall agree within 0.005"C. A2.2.3.4 Record the ice-point readings and determine the thermometer correction at this temperature from the mean reading. If the correction is found to be higher or lower than that corresponding to a previous calibration, change the correction at all other temperatures by the same value. A2.2.3.5 During the procedure, apply the following conditions: (a) The thermometer shall be supported vertically. (b) View the thermometer with an optical aid that gives a magnification of approximately five and also eliminates parallax. (c) Express the ice-point reading to the nearest 0.005"C. A2.2.4 When in use, immerse the thermometric device to the same depth as when it was fully calibrated. For example, if a liquid-in-glass thermometer was calibrated at the normal total immersion condition, it shall be immersed to the top of the mercury column with the remainder of the stem and the expansion volume at the uppermost end exposed to room temperature and pressure. In practice, this means that the top of the mercury column shall be within a length equiva-

A2.1 Short-Range Specialized Thermometer A2.1.1 Use a short-range specialized thermometer conforming to the generic specification given in Table A2.1 and to one of the designs shown in Fig. 1. A2.1.2 The difference in the designs rests mainly in the position of the ice point scale. In Design A, the ice point is within the scale range, in Design B, the ice point is below the scale range, and in Design C, the ice point is above the scale range. A2.2 Calibration A2.2.1 Use liquid-in-giass thermometers with an accuracy after correction of 0.020C or better, calibrated by a laboratory meeting the requirements of ISO 9000 or ISO 25, and carrying certificates confirming that the calibration is traceable to a national standard. As an alternative, use thermometric devices such as platinum resistance thermometers, of equal or better accuracy, with the same certification requirements. A2.2.2 The scale correction of liquid-in-glass thermometers can change during storage and use, and therefore regular re-calibration is required. This is most conveniently achieved in a working laboratory by means of a re-calibration of the ice point, and all of the main scale corrections altered for the change seen in the ice point. A2.2.2.1 It is recommended that the interval for ice-point checking be not greater than six months, but for new thermometers, monthly checking for the first six months is recommended. A complete new re-calibration of the thermometer, while permitted, is not necessary in order to meet the accuracy ascribed to this design thermometer until the ice-point change from the last full calibration amounts to one scale division, or more than five years have elapsed since the last full calibration. A2.2.2.2 Other thermometric devices, if used, will also require periodic recalibration. Keep records of all re-calibration. A2.2.3 Procedurefor Ice-point Re-calibration of Liquid-

in-glass Thermometers. TABLE A2.1 General Specification for Thermometers NoTs--Table A2.2 gives a range of ASTM, IP, and ASTM/IP thermometers that comply with the specification in Table A2.1, together with their designated test temperatures. See Specification E 1 and Test Method E 77.

Immersion Scale marks: Subdivisions Long lines at each Numbers at each Maximum line width Scale error at test temperature, max Expansion chamber: Permit heating to Total length Stem outside diameter Bulb length Bulb outside dian~eter Length of scale range

TABLE A2.2 Thermometer No.

Total °C *C *C mm oC

ASTM 132C, IP 102C 150 ASTM 110C, F/IP 93C 135 ASTM 121C/IP 32C 98.9, 100 ASTM 129C, F/IP 36C 93.3 ASTM 48C, F/IP 90(3 82.2 IP 100C 80 ASTM 47C, F/IP 35C 60 ASTM 29C, F/IP 34C 54.4 ASTM 46C F/IP 66C 50 ASTM 120C/IP 92C 40 ASTM 28C, F/IP 31C 37.8 ASTM 118C, F 30 ASTM 45C, F/IP 30C 25 ASTM 44C, F/IP 29C 20

0.05 0.1 end 0.5 1 0.10 0.1

°C 105 up to 90, 120 between 90 and 95 130 between 95 and 105, 170 above 105 mm 300 to 310 mm 6.0 to 8.0 mm 45 to 55 mm no greater than stem mm 40 to 90

132

Complying Thermometers

Test Temperature oc oF

275 210, 212 200 180 140 130 122 100 86 77 68

Thermometer No.

ASTM 128C, F/IP 33C ASTM 72C, F/IP 67C ASTM 127C/IP 99C ASTM 126C, F/IP71C ASTM 73C, F/IP 68C ASTM 74C, F/IP 69C

Test Temperature *C oF

0 32 -17.8 0 -20 -4 -26.1 -20 -40 -40 -53.9 -65

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D 445

lent to four scale divisions of the surface of the medium whose temperature is being measured,

A2.2.4.1 If this condition cannot be met, then an extra correction may be necessary.

A3. T I M E R ACCURACY WWV WWVH CHU

A3.1 Regularly check timers for accuracy and maintain records of such checks. A3.1.1 Time signals as broadcast by the National Institute of Standards and Technology are a convenient and primary standard reference for calibrating timing devices. The following can be used to an accuracy of 0.1 s:

Fort Collins, CO Kauai, HI Ottawa, Canada

2.5, 5, 10, 15, 20 MHz 2.5, 5, 10, 15, MHz 3.33, 7.335, 14.67 MHz

A3.1.2 Radio broadcast of voice and audio on a telephone line at phone 303-499-7111. Additional time services are available from the National Institute of Standards and Technology.

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and ff not revised, either reepproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend, ff you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 100 Barr Harbor Drive, West Conshohockan, PA 19428.

133

(~l~ Designation: D 447 - 93 Standard Test Method for Distillation of Plant Spray Oils 1 This standard is issued under the fixed designation D 447; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (e) indicates an editorial change since the last revision or reapproval.

D 850 Test Method for Distillation of Iadustrial Aromatic Hydrocarbons and Related Materials 2 D 1078 Test Method for Distillation Range of Volatile Organic Liquids2 E 133 Specification for Distillation Equipment 3 E 220 Method for Calibration of Thermocouples by Comparison Techniques 4

5. Apparatus 5.1 All items listed in 5.1.1 to 5.1.7 shall conform to Specification E 133. All of the following references are to Specification E 133: 5.1.1 Distilling Flask, Flask B (125 mL). 5.1.2 Condenser and Cooling Bath, Section 5 and Figs. I and 2 of Specification E 133. 5.1.3 Heater, Section 7 and Figs. 1 and 2 of Specification E 133. 5.1.4 Flask Support, Board C [51 mm (2.0-in.) hole]. An additional board, which will completely cover the top of the shield, is split and recessed to fit the neck of the flask. 5.1.5 Graduated Cylinder, Graduate B, 100 mL, as shown in Fig. 4 of Specification E 133. The cylinder must have graduations at the 5 mL level and from 90 to 100 mL in 1-mL increments. For automatic apparatus, the cylinder shall conform to the physical specifications described in this section, with the exception of the graduations. 5.1.5.1 For automatic apparatus, the level follower/recording mechanism of the apparatus will have a resolution of 0.1 mL, with an accuracy of :t:1 mL. The calibration of the assembly should be confirmed according to the manufacturer's instructions at regular intervals. The typical calibration procedure involves the verification of the output with the receiver containing 5 and 100 mL of material, respectively. 5.1.6 Temperature Sensor: 5.1.6.1 ASTM Thermometer 8C (8F) as prescribed in Section 10 of Specification E 133.

3. Summary of Test Method 3.1 A 100 mL sample is distilled in a 125-mL flask at a rate of 4 to 6 mL/min. The temperature is recorded at 5 mL distilled intervals.

NOTE l--Thermometers heated to high temperatures, in the range required for spray oil distillations,sometimes develop stresses that may affect the accuracy of calibration. It is recommended that, when thermometers vary from the standard thermometer when checked at any convenient temperature, the thermometers be allowed to rest at room temperature for at least 24 h to relieve stresses.

1. Scope 1.1 This test method covers the determination of the volatility of plant spray oils by means of distillation. Its primary purpose is to establish the classification of a spray oil by determining the fraction distilled at specified temperatures. Both a manual method and an automatic method are specified. 1.2 In cases of dispute, the referee test method is the manual test method. 1.3 The values stated in SI units are to be regarded as the standard. The values in parentheses are for information only. 1.4 This standard does not purport to address all of the

safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements, see Note 3. 2. Referenced Documents

2.1 A S T M Standards:

5.1.6.2 Temperature measurement systems using thermocouples or resistance thermometers must exhibit the same temperature lag and accuracy as the equivalent mercury in glass thermometers. Confirmation of the calibration of these temperature sensors is to be made on a regular basis. This can be accomplished as described in Method E220, potentiometrically by the use of standard precision resistance, depending on the type of probe. Another technique is to distill pure toluene in accordance with Test Method D 850 and compare the temperature indicated with that shown by the above mentioned mercury in glass thermometers when carrying out a manual test under the same condition.

4. Significance and Use 4.1 To obtain optimum persistence with minimal damage to fruit and foliage, a plant spray oil should possess appropriate volatility characteristics, as indicated by distillation. A narrow range, for example, 55"C, ensures uniform evaporation, while the proper level of initial and final boiling points prevents either too rapid or undesirably prolonged evaporation of the oil. t This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.08 on Volatility. Current edition approved Feb. 15, 1993. Published May 1993. Originally published as D 447 - 37 T. Last previous edition D 447 - 88. 2 Annual Book of ASTM Standards, Vol 06.04. 3 Annual Book of ASTM Standards, Vols 05.03 and 14.02. 4 Annual Book of A S T M Standards, Vol 14.03.

NOTE 2--Toluene is shown in reference manuals as boiling at 110.6"C under the conditions of Test Method D 1078, which uses a partial immersion thermometer. Because this test method uses total immersion thermometers, the results will be lower. The approximate value for an 8C thermometer is 110.0"C.

134

4{~) D 447 TABLE 1

Temperature Correction as Function of Pressure

TemperatureObserved,°C

Corroction/kPa

204 260 316 336 371

0.43 0.48 0.53 0.55 0.58

The distillation never "catches up," and all subsequent points will be in error. 7.5 Record the temperature as each 5 mL or other specified amounts of distillate are collected; also record the volume of condensate at any specified temperature, these volumes being uncorrected for temperature. Continue as described until 95 mL have been collected in the receiver, unless cracking occurs sooner. Cracking will be observed by an increase in the distilling rate, with erratic thermometer readings; an effort to adjust the rate will usually result in a decided drop in temperature reading. 7.6 Record the barometric pressure prevailing during the distillation.

5.1.7 Water B a t h m A suitable water bath maintained at boiling temperature, in which the cylinder can be immersed to the top graduation mark.

6. Reagents and Materials 6.1 Petroleum Ether, with a boiling range from 35 to 60°C, or IP Petroleum Spirit 40/60. (Warning--See Note 3). NOTE 3: Warning--Extremely flammable. Skin irritant on repeated contact. Aspiration hazard. 7. Procedure 7.1 Swab the condenser tube to remove any liquid remaining from the previous determination. A piece of soft cloth attached to a cord or copper wire is satisfactory for this purpose. 7.2 Measure I00 m L of the sample at 21 to 27°C into the 100-mL cylinder, and pour it into the distilling flask, allowing the cylinder to drain for 30 s. Hold or support the cylinder at the top graduation mark in a boiling water bath for approximately I rain, then allow the cylinder to drain again into the flask for 30 s. Rinse the cylinder with petroleum ether, blow dry, and place the same cylinder at the outlet of the condenser in such a position that the condenser tube extends approximately 25 mm into the graduate but not below the 100-mL mark. Do not place cylinder in contact with the tip of condenser tube. 7.3 Check the thermometer for accuracy at any convenient temperature, and then install the thermometer, provided with a cork, in the neck of the flask so that the bulb is in the center of the neck, and the top of the bulb (that is, the end of the enamel backing) is level with the inside of the bottom of the vapor outlet tube at its highest point. Place the flask on the 51 mm (2.0 in.) hole in the flash support with the vapor outlet tube inserted into the condenser tube, making a tight connection by means of a cork. Adjust the flask so that it fits the vertical-edged hole in the flask support snugly. The vapor tube should be parallel to the condenser tube and extend into it not less than 25 mm nor more than 51 ram. Cover the shield with the split board, which should fit the neck of the flask closely. 7.4 Maintain the temperature of the condenser bath at 57 to 63°C throughout the distillation. Heat the flask at a uniform rate, so regulated that the first drop of condensate falls from the condenser in not less than 10 nor more than 15 rain; record the temperature when this occurs. Continue the distillation, adjusting the heat so as to maintain a rate of not less than 4 nor more than 6 mL/min. Permit the oil to fall directly into the graduate, and not flow down the side. 7.4.1 Too much stress cannot be placed on the necessity for maintaining the distillation rate. It must at all times be within the 4 to 6 mL/min specified, preferably as close to 5 mL/min as possible. If the rate falls outside of these limits at any point, discard any results and repeat the determination. 135

8. Calculation 8.1 Correct the observed temperature readings, if the barometric pressure varies from 101.3 kPa (760 mm Hg) by more than 1.3 kPa (10 mm Hg), by means of either of the following two equations: Temperature Correction, "C: Cc ffi 0.0009 (101.3 - P~) (273 + to) (1) Cc = 0.00012 (760 -/'2) (273 + t,) (2) where: Cc = correction to be added to the observed vapor temperature, to P~ ffi barometric pressure, kPa, prevailing at the time of test, and P2 ffi barometric pressure, mm Hg, prevailing at the time of test. NOtE 4--The calculated correction factors within the temperature range encountered in the distillation,as shown in Table I, will affectthe temperature recordedat any given volume by more than 0.4"(2when the barometric pressure varies from 101.3 kPa by more than 1 kPa. 8.2 Correct the temperature readings from 8.1 in accordance with the thermometer calibration. Report the final corrected initial boiling point and temperature of each 5 % distilled or other specified amounts. 8.3 When the percentage distilled at a certain temperature is required and the barometric pressure varies from 760 mm Hg by more than 100 ram, use the temperature corrected to 760 m m Hg prior to the distillation. NOTE 5--Instead of correcting the temperature prior to the distillation, it is permissibleto plot the final corrected temperatures against the corresponding percentages and report the indicated percentage at the required temperature from the curve. 9. Precision and Bias 9.1 Precision--The precision of the manual test method as determined by the statistical examination of interlaboratory test results is as follows: 9.1.1 RepeatabzTity---Tbe difference between successive test results, obtained by the same operator with the same apparatus under constant operating conditions on identical test material would, in the long run, and in the normal and correct operation of the test method, exceed the following values only in one case in twenty:

~l~ D 447 Thermometer readins at specified:

Thermometer v-A._din8at specified: % Recovered 10 50 90 Percent recovered at 335.6"C

% Recovered

Repeatability, "C 2.2 1.7 2.2 2%

10 50 90 Percent recovered at 335.6"C

9.1.2 Reproducibility--The difference between two, single and independent results obtained by different operators working in different laboratories on identical test material would, in the long run, and in the normal and correct operation of the test method, exceed the following values only in one case in twenty:

Reproducibility, "C 5.0 3.9 5.0 4%

9.2 The precision of the test method using automatic equipment has not been determined. 9.3 Bias: 9.3.1 Since there is no accepted reference material suitable for determining the bias for the procedure in this test method, a statement on bias cannot be estimated. 9.3.2 The bias between the manual and the automatic test method has not been determined. 10. Keywords 10.1 distillation; plant spray oils; spray oils; volatility

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any Item mentioned In this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard Is subject to revision at any time by the responslbie technical committee and must be reviewed every five years and If not revised, either ~ e d or withdrawn. Your comments are invited either for revision of this standard or for eddIflonai standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at s meeting of the responsible technical committee, which you may attend. If you feel that your comments have not recaived a fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St., Pbiledaiphie, PA 19103.

136

@

Designation: D 473 - 81 (Reapproved 1995) E2

An American Standard Bdtish Standard 4382

Designation: Manual of Petroleum Measurement Standards, Chapter 10-1 (MPMS)

IP@ IHI IN~llLtlll

Designation: 53/82

CHpIIRIDIlU~t

Standard Test Method for Sediment in Crude Oils and Fuel Oils by the Extraction Method 1 This standard is issued under the fixed designation D 473; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (~) indicates an editorial change since the last revision or re.approval.

Thts test method has been approved by the sponsoring committees and accepted by the Cooperating Societies in accordance with established procedures This method was issued as a joint ASTM-API.IP standard in 1981. This test method has been approved for use by agencies of the Department of Defense. Consult the DoD Index of Specifications and Standards for the specific year of issue whtch has been adopted by the Department of Defense. ~ NoTE--Section 12 was added editorially in September 1995. ~2 NotE--Editorial corrections were made throughout in November 1996.

1. Scope 1.1 This test method covers the determination of sediment in crude oils and fuel oils by extraction with toluene.

3. Summary of Test Method 3.1 A test portion of a representative oil sample, contained in a refractory thimble, is extracted with hot toluene until the residue reaches constant mass. The mass of residue, calculated as a percentage, is reported as "sediment by extraction."

NOTE l--Precision on recycled oils and crank case oils is u n k n o w n and additional testing is required to determine that precision.

1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific precautionary statements, see 6.1 and 7.1.

4. Significance and Use 4.1 A knowledge of the sediment content of crude oil and fuel oils is important both to the operation of refining and the buying or selling of the oil. 5. Apparatus 5.1 Extraction Apparatus (see Figs. 1 and 2) consisting of the parts described in 5.1.1 through 5.1.6. 5.1.1 Extraction Flask--A wide-neck Erlenmeyer flask of 1-L capacity. 5.1.2 Condenser--A condenser in the form of a metal coil approximately 25 mm in diameter and 50 mm in length

2. Referenced Documents 2.1 A S T M Standards: D4057 Practice for Manual Sampling of Petroleum and Petroleum Products2 D 4177 Practice for Automatic Sampling of Petroleum and Petroleum Products2 2.2 API Standard." MPMS8, "Sampling Petroleum and Petroleum Products "3 2.3 ISO Standards.~ 4793 Laboratory Apparatus--Filters--Porosity Grading 5272 Toluene--Specifications

CONOE~R

This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.02 on Static Petroleum Measurement. Current edition approved March 27, 1981. Published May 1981. Originally published as D 473 - 38T. Last previous edition D 473 - 69 (1979). 2 Annual Book of ASTM Standards, Vol 05.02. 3Available from the American Petroleum Institute, 1220 L St., N.W., Washington, D.C. 20005. 4 Available from American National Standards Institute, I 1 W. 42nd St., 13th Floor, New York, NY 10036.

I

~

•

CO~O~NS~A

I VOPOF,40~~,*lt

NOTE--Apparatus B shows the water cup in position. FIG. 1 Extraction Apparatus for Determination of Sediment

137

~ ATTACH TO HOOKS ON UNDERSIDE OF CONDENSER LID

D 473 ATTACH THROUGH CONDENSER LOOP

\

ALL JOINTS SILVER SOLDERED

ALL JOINTS SILVER SOLDERED

RIBBON SUPPORT B

WIRE SUPPORT A NOTE~Ilver solder should be used on all joints.

FIG. 2 Basket ThimbleSupport attached to, and with the ends projecting through a lid of sufficient diameter to cover the neck of the flask is shown in Fig. 1. The coil should be made from stainless steel, tin, tin-plated copper, or tin-plated brass tubing having an outside diameter of 5 to 8 mm and a wall thickness of 1.5 mm. If constructed of tin-plated copper or brass, the tin coating shall have a minimum thickness of 0.075 mm. The exposed surface of the coil for cooling purposes is about 115 cm 2, 5.1.3 Extraction Thimble--The extraction thimble should be of a refractory porous material, pore size index P16, 25 mm in diameter by 70 mm in height, weighing not less than 15 g and not more than 17 g. The thimble shall be suspended from the condenser coil by means of a basket so that it hangs approximately midway between the surface of the extracting solvent and the bottom of the condenser coil. 5.1.4 Thimble Basket--The thimble basket shall be corro-

sion-resistant; shall be made of platinum, stainless steel, nickel-chromium alloy, or similar material; and shall meet the requirements of Fig. 2. 5.1.5 Water CupmA water cup shall be used when testing a sample having a high-water content (see Fig. I B). The cup shall be made of glass, shall be conical in shape, shall be approximately 20 mm in diameter and 25 mm deep, and shall have a capacity of approximately 3 mL. A glass hook fused on the rim at one side is so shaped that when hung on the condenser the cup hangs with its rim reasonably level. In this procedure, the thimble basket is suspended either as shown in Fig. 1A by means of the corrosion-resistant wire looped over the bottom of the condenser coil and attached to the basket supports or as in Fig 1B where the wire supports of the basket are attached to hooks soldered to the underside of the condenser lid. 5.1.6 Source of HeatmA source of heat, preferably a hot plate, suitable for vaporizing toluene. 138

~

D 473 masses of the dried thimble plus sediment after two successive extractions do not differ by more than 0.2 mg.

6. Solvent

6.1 Toluene, conforming to ISO 5272, Grade 2. NOTE 2--Warning--Flammable.

9. Calculation 9.1 Calculate the mass of the sediment as a percent of that of the original sample as follows:

6.1.1 The typical ch~iracteristics for the reagent are: Color (APHA) Boiling range (initial to dry point) A Residue after evaporation Substances darkened by H2SO4 Sulfur compounds (as S) Water (H20) (by Karl Fischer titration)

10 2.0°C 0.001% passes ACS test 0.003 % 0.03 %

Mass %

=

mass sediment

original sample mass

x 100

A Recorded boiling point 110.6"C.

7. Sampling

10. Report

7. I Sampling is defined as all steps required to obtain an aliquot of the contents of any pipe, tank, or other system and to place the sample into the laboratory test container. 7.2 Only representative samples obtained as specified in Practices D4057 and D4177 shall be used for this test method.

10.1 Report the results to the nearest 0.01% as the mass percent of sediment by extraction (Note 3). The test report shall reference this Test Method D 473 as the procedure used. NOTE 3--Since water and sediment values commonly are reported as volume percent, calculate the volume of the sediment as a percent of the original sample. As a major portion of the sediment probably would be sand (silicon dioxide, which has a relative density of 2.32) and a small amount of other naturally occurring materials (with a relative density lower than that of sand), use an arbitrary relative density of 2.0 for the resulting sediment. Then, to obtain volume percent sediment, divide the mass percent sediment multiplied by the relative density of the crude at 15"C (use 0.85 relative density, if unknown) by 2.

8. Procedure 8. I For referee tests, use a new extraction thimble. For routine tests, thimbles may be reused. Before reusing a thimble, it must be heated to a dull red heat (prefetably in an electric furnace) to remove the combustible portion of the accumulated sediment. Subject the thimble to a preliminary extraction as described in 8.2 before being used for another determination. 8.2 Before using a new thimble, rub the outside surface with fine sandpaper and remove all loosened material with a stiff brush. Give the thimble a preliminary extraction with the toluene, allowing the solvent to drip from the thimble for at least 1 h. Then dry the thimble for 1 h at a temperature of 115 to 120"C; cool in a desiccator, without desiccant, for 1 h, and weigh to the nearest 0.1 mg. Repeat this extraction until the masses of the thimble after two successive extractions do not differ by more than 0.2 mg. 8.3 Place an estimated 10-g test portion of the sample in the thimble immediately after the sample has been mixed as described in Practice D 4057 and Method D 4177. Do not attempt to adjust this estimated 10-g portion to any exact predetermined amount. Weigh to the nearest 0.01 g. Place the thimble in the extraction apparatus, and extract with the hot toluene for 30 min after the solvent dropping from the thimble is colorless. Ensure that the rate of extraction is such that the surface of the mixture of oil and toluene in the thimble does not rise higher than to within 20 m m of the top. 8.4 When testing samples having a high water content, use the assembly shown in Fig. lB. In this procedure, any water in the test portion is removed as its toluene azeotrope and is collected in the water cup, where it separates as a bottom layer. The toluene layer overflows into the thimble. If the cup becomes full of water, allow the apparatus to cool and empty the cup. 8.5 After the extraction is completed, dry the thimble for 1 h at 115 to 120"C; cool in a desiccator, without desiccant, for 1 h and weigh to the nearest 0.2 rag. 8.6 Repeat the extraction, allowing the solvent to drip from the thimble for at least 1 h but not longer than 1.25 h; dry, cool, and weigh the thimble as described in 9.5. Repeat this extraction for further 1-h periods, if necessary, until the

Volume % = mass % sediment 2.0 x (crude relative density or 0.85 if unknown) 11. Precision 11.1 The precision of this test method, as based on mass percent and examination of interlaboratory test results in the range 0 to 0.4 % is described in 1 l. 1.1 and 11.1.2. 11.1.1 Repeatability--The difference between successive test results, obtained by the same operator with the same apparatus under constant operating conditions on identical test material, would, in the long run, in the normal and correct operation of the test method, exceed the following value in only one case in twenty: 0.017 + 0.255 S where: S = average result in percent. 11.1.2 ReproducibilitymThe difference between two single and independent test results obtained by different operators working in different laboratories on identical test material, would, in the long run, in the normal and correct operation of the test method, exceed the following value in only one case in twenty: 0.033 + 0.255 S where: S = average result in percent. 12. Keywords 12.1 apparatus; crude oil; extraction; fuel oil; procedure; sampling; sediment 139

I~) D 473

ANNEX

(Mandatory Information) AI. PRECAUTIONARY INFORMATION A 1.1 Toluene PrecautionmKeep away from heat, sparks, and open flame. Vapor harmful. Toluene is toxic.

Particular care must be taken to avoid breathing the vapor and to protect the eyes. Keep container closed. Use with adequate ventilation. Avoid prolonged or repeated contact with the skin.

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted In connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed avery five years and ff not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend, ff you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 100 Barr Harbor Drive, West Conahohockan, PA 19428.

140

@ IPW till i ~ i i illll q~l I , H m . l u u

Designation: D 482 - 95

An Amencan National Standard Bntlsh Standard 4450

Designation: 4/94

Standard Test Method for Ash from Petroleum Products 1 This standard is issued under the fixed designation D 482; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parenthesis indicates the year of last reapproval. This is also a standard of the Institute of Petroleum issued under the fixed designation IP 4. The final number indicates the year of last revision.

This test method was adopted as a joint ASTM-IP standard in 1965. This standard has been adopted for use by government agencies to replace Method 5421 of Federal Test Method Standard No. 791b. Consult the DoD Index of Specifications and Standards for the spectfic year of issue which has been adopted by the Department of Defense.

1. Scope 1.1 This test method covers the determination of ash in the range 0.001-0.180 mass %, from distillate and residual fuels, gas turbine fuels, crude oils, lubricating oils, waxes, and other petroleum products, in which any ash-forming materials present are normally considered to be undesirable impurities or contaminants (Note 1). The test method is limited to petroleum products which are free from added ash-forming additives, including certain phosphorus compounds (Note 2).

D4928 Test Method for Water in Crude Oils by Coulometric Karl Fischer Titration 4 3. Summary of Test Method 3.1 The sample contained in a suitable vessel is ignited and allowed to burn until only ash and carbon remain. The carbonaceous residue is reduced to an ash by heating in a muffle furnace at 775"C, cooled and weighed. 4. Significance and Use 4.1 Knowledge of the amount of ash-forming material present in a product can provide information as to whether or not the product is suitable for use in a given application. Ash can result from oil or water-soluble metallic compounds or from extraneous solids such as dirt and rust.

NOTE 1 - - I n certain types of samples, all of the ash-forming metals

are not retained quantitatively in the ash. This is particularly true of distillate oils, which require a special ash procedure in order to retain metals quantitatively. NOTE 2--This test method is not intended for the analysis of unused lubricating oils containing additives; for such samples use Test Method D 874. Neither is it intended for the analysis of lubricating oils containing lead nor for used engine crankcase oils.

5. Apparatus 5.1 Evaporating D&h or Crucible, made of platinum, silica, or porcelain, of 90 mL minimum capacity to 120-mL maximum capacity. 5.2 Electric Muffle Furnace, capable of maintaining a temperature of 775 + 25"C and preferably having suitable apertures at the front and rear so as to allow a slow natural draught of air to pass through. 5.3 Meeker Gas Burner, or equivalent.

1.2 The preferred units are mass %.

1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

5.4 Mechanical Shaker.5 2. Referenced Documents

6. Reagents

2.1 ASTM Standard:

6.1 Propan-2-ol.

D 874 Test Method for Sulfated Ash from Lubricating Oils and Additives 2 D4057 Practice for Manual Sampling of Petroleum and Petroleum Products 3

6.2 Toluene. 7. Sampling 7.1 Take samples in accordance with the instructions in Practice D4057. Before transferring the portion of the sample to be ashed to the evaporating dish or crucible, take particular care to ensure that the portion taken is truly representative of the larger portion. Vigorous shaking can be necessary.

J This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.03 on Elemental Analysis. Current edition approved Apr. 15, 1995. Published June 1995. Originally published as D 482 - 38 T. Last previous edition D 482 - 91 ~J. In the IP, this method is under the jurisdiction of the Standardization Committee. 2 Annual Book t f A S T M Standards, Vol 05.0 I. 3 Annual Book of ASTM Standards, Vol 05.02.

4 Annual Book of ASTM Standards', Vol 05.03. 5 A satisfactory mechanical shaker is available from the Eberbach Corp., 505 S. Maple Rd., Ann Arbor, MI 48106-1024.

141

~

D 482 8.6 Carefully heat the dish or crucible with a Meeker burner or equivalent until the contents can be ignited by the flame. Maintain the dish or crucible at such a temperature that the sample continues to burn at a uniform and moderate rate leaving only a carbonaceous residue when the burning ceases. A hot plate can be used at this stage. 8.6.1 The sample may contain water that can cause spattering. The operator must heat the sample cautiously while wearing goggles. If the spattering is very severe so that material escapes the confines of the dish or the crucible, discard the sample. 8.6.2 To a second sample, add 2 mL of propan-2-ol (Warning-Flammable) and stir into the test specimen (gently warmed to liquefy if it is solid or near solid) using a glass rod, and proceed as in 7.6. If this is unsuccessful, repeat using a 10 mL mixture of toluene (Warning-Flammable. Vapor Harmful) and propan-2-ol. In either case, any test specimen that adheres to the glass rod can be returned to the dish using a strip of ashless filter paper. Continue burning as outlined in 8.6. 8.7 Vigilance by the operator is mandatory; burning samples must never be left unattended. 8.8 Some test specimens will require extra heating after the burning has ceased, particularly heavy samples such as marine fuels which form crusts over the unburned material. The crust can be broken with a glass rod. Any crust that adheres to the glass rod can be returned to the dish using a strip of ashless filter paper. Burn the remaining test specimen. 8.9 The heavier material tends to foam, therefore the operator must exercise considerable care. Overheating must be avoided so that neither the test specimen nor the dish are heated to a red hot appearance, as this can result in loss of ash. Likewise, the flame must never be higher than the rim of the dish to avoid superheating the crust, thereby producing sparks that can result in considerable loss of ash. 8.10 Heat the residue in the muffle furnace at 775 + 25"C until all carbonaceous material has disappeared. Cool the dish to room temperature in a suitable container (Note 3), and weigh to the nearest 0.1 rag. 8.11 Reheat the dish at 775"C for 20 to 30 min, cool in a suitable container (Note 3), and reweigh. Repeat the heating and weighing until consecutive weighings differ by not more than 0.5 rag.

8. Procedure 8.1 Heat the evaporating dish or crucible at 700 to 8000C for 10 rain or more. Cool to room temperature in a suitable container, and weigh to the nearest 0.1 mg. NOTE 3raThe container in which the dish or crucible is cooled can be a desiccator not containing a desiccating agent. In addition, all weighings o f the crucibles should be performed as soon as the crucibles have

cooled. If it should be necessary that the crucibles remain in the desiccator for a longerperiod, then all subsequentweighingsshould be made after allowing the crucibles and contents to remain in the desiccator for the same lengthof time. 8.2 If the sample is sufficiently mobile, mix thoroughly before weighing. The mixing is necessary to distribute catalyst fines and other particulate material throughout the sample. Satisfactory mixing can usually be achieved by 10 min of manual shaking or 10 min using a mechanical shaker. Examine the sample for homogeneity before proceeding with 8.3. Continue mixing the sample if it is not homogeneous. 8.2.1 When it is evident that the sample is not homogenized atter repeated mixings, or there is a reasonable doubt, a non-aerating, high-speed shear mixer can be used. Such a device is described in Annex AI of Test Method D 4928. 8.2.2 When the sample cannot be satisfactorily homogenized, reject the sample and acquire a new sample. 8.2.3 When the sample is viscous or solid at room temperature, heat the container carefully until the sample is entirely liquid and mix carefully. An oven at an appropriate temperature can be used. 8.2.4 The sample can contain water. After heating in an oven, the water can boil causing spattering or foaming. The operator must proceed cautiously with the heating step, wearing safety goggles and gloves. Mixing this type of sample must be done carefully. Stirring, rather than shaking, is an option. 8.3 The quantity of test specimen taken for testing will depend upon the ash content expected in the sample. Refer to Table I. The weighing procedure will also depend upon whether the sample requires heating or not, and whether more than one portion has to be weighed. 8.4 Using a top-loading balance, weigh into the dish or crucible, sufficient test specimen to the nearest 0. l g to yield l to 20 rag of ash. Determine the mass of the test specimen taken from the difference between the initial and final masses of the sample container weighed at ambient temperature. If one weighing is sufficient, as determined from Table l, or experience, proceed with steps 8.6 through 8.1 I. 8.5 If more than one addition of test specimen is required, proceed only through 8.6 (noting 8.6.1 and 8.7) and allow the dish or crucible to cool to ambient temperature before adding more sample as outlined in 8.4. Proceed with steps 8.6 through 8. l I.

9. Calculation 9.1 Calculate the mass of the ash as a percentage of the original samples as follows: Ash, mass % = ( w / W ) x 100 where: w = mass of ash, g, and W = mass of sample, g.

TABLE 1 Test Specimen Mass Versus Ash Expected Ash, mass ~

Test Specimen, mass, g

Ash Mass, mg

0.18 0.10 0.05 0.04 0.02 0.01 0.001

9 20 40 50 100 100 100

20 20 20 20 20 10 1

10. Report 10.1 Report the results as follows: Test Specimen Mass 9.00 to 39.99 g 40.00 or more g

Report 3 decimal places 3 to 4 decimal places

10.2 Record the value reported as ash in accordance with Test Method D 482, stating the mass of the sample taken.

142

~

D 482 1 I. 1.2 Reproducibifity--The difference between two single and independent results obtained by different operators in different laboratories on identical test material would, in the long run, in the normal and correct operation of the test method, exceed the following values only in one case in twenty:

11. Precision and Bias 6

11.1 The precision of this test method as obtained by statistical examination of interlaboratory test results is as follows: 11.1.1 Repeatability--The difference between successive tests results, obtained by the same operator with the same apparatus under constant operating conditions on identical test material would, in the long run, in the normal and correct operation of the test method, exceed the following values only in one case in twenty: Ash, mass %

Repeatability

0.001 to 0.079 0.080 to 0.I 80

0.003 0.007

Ash, mass %

Reproducibility

0.001 to 0.079 0.080 to 0.180

0.005 0.024

11.2 BiaswThe bias of this test method cannot be determined since an appropriate standard reference material containing a known level of ash in liquid petroleum hydrocarbon is not available. 12. Keywords

12.1 ash; crude oils; distillate oils; fuel oils; lubricating oils

6 No ASTM Research Report is available for this standard.

The American Society for Testing and Materials takes no poslhon respecting the validity of any patent rtghts asserted in connechon with any item menttoned in thts standard Users of thts standard are expressly advtsed that determination of the vahdtty of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical commtttee and must be reviewed every hve years and ff not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will recewe careful consideration at a meeting of the responsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 100 Barr Harbor Drive, West Conshohocken, PA 19428.

143

Designation: D 524 - 97

T H [ INSTITUTE Of ~ O L E U M

An Amertum Naeonal Stanclam British Stanclard 4461

Designation: 14/94

Standard Test Method for Ramsbottom Carbon Residue of Petroleum Products I This standard is issued under the fixed designation D 524; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (d indicates an editorial change since the last revision or reapproval.

This test method has been approvedfor use by agencies of the Department of Defense. Consult the DoD Index of Specifications and Standards for the specific year of issue which has been adopted by the Department of Defense. This test method has been adoptedfor use by government agencies to replace Method 5002 of Federal Test Method Standard No. 791b.

1. Scope 1.1 This test method covers the determination of the amount of carbon residue (Note 1) left after evaporation and pyrolysis of an oil, and is intended to provide some indication of relative coke-forming propensity. This test method is generally applicable to relatively nonvolatile petroleum products which partially decompose on distillation at atmospheric pressure. Petroleum products containing ash-forming contituents as determined by Test Method D 482, will have an erroneously high carbon residue, depending upon the amount of ash formed (Notes 2 and 3). NOTE l - - T h e term carbon residue is used throughout this test

method to designate the carbonaceous residue formed during evaporation and pyrolysis of a petroleum product. The residue is not composed entirely of carbon, but is a coke which can be further changed by pyrolysis. The term carbon residueis continued in this test method only in deference to its wide common usage. NOTE 2--Values obtained by this test method are not numerically the same as those obtained by Test Method D 189, or Test Method D 4530. Approximate correlations have been derived (see Fig. X2.1) but need not apply to all materials which can be tested because the carbon residue test is applicable to a wide variety of petroleum products. The Ramsbottom Carbon Residue test method is limited to those samples that are mobile below 90°C. NOTE 3--In diesel fuel, the presence of alkyl nitrates such as amyl nitrate, hexyl nitrate, or octyl nitrate, causes a higher carbon residue value than observed in untreated fuel, which can lead to erroneous conclusions as to the coke-forming propensity of the fuel. The presence of alkyl nitrate in the fuel can be detected by Test Method D 4046. 1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

2. Referenced Documents

2.1 A S T M Standards: i This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.06 on Analysis of Lubricants. Current edition approved Jan. 10, 1997. Published October 1997. Originally published as D 524 - 39 T. Last previous edition D 524 - 95. In the IP, this test method is under the jurisdiction of the Standardization Committee.

D 189 Test Method for Conradson Carbon Residue of Petroleum Products 2 D 482 Test Method for Ash from Petroleum Products 2 D 4046 Test Method for Alkyl Nitrate in Diesel Fuels by Spectrophotometry 3 D 4057 Practice for Manual Sampling of Petroleum and Petroleum Products 3 D4175 Terminology Relating to Petroleum, Petroleum Products, and Lubrieants 3 D 4177 Practice for Automatic Sampling of Petroleum and Petroleum Products 3 D4530 Test Method for Determination of Carbon Residue (Micro Method) 3 E 1 Specification for ASTM Thermometers 4 E 133 Specification for Distillation Equipment 5 3. Terminology 3.1 Definitions.. 3.1.1 carbon residue, n--the residue formed by evaporation and thermal degradation of a carbon containing material. D 4175 3.1.1.1 Discussion--The residue is not composed entirely of carbon but is a coke that can be further changed by carbon pyrolysis. The term carbon residue is retained in deference to its wide c o m m o n usage.

4, Summary of Test Method 4.1 The sample, after being weighed into a special glass bulb having a capillary opening, is placed in a metal furnace maintained at approximately 550°C. The sample is thus quickly heated to the point at which all volatile matter is evaporated out of the bulb with or without decomposition while the heavier residue remaining in the bulb undergoes cracking and coking reactions. In the latter portion of the heating period, the coke or carbon residue is subject to further slow decomposition or slight oxidation due to the possibility of breathing air into the bulb. After a specified heating period, the bulb is removed from the bath, cooled in a desiccator, and again weighed. The residue remaining is 2Annual Book of ASTM Standards, Vol 05.01. 3Annual Book of ASTM Standards, Vol 05.02. 4 Annual Book of ASTM Standards, Vol 14.03. 5Annual Book of ASTM Standards, Vol 14.02.

144

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D 524

calculated as a percentage of the original sample, and reported as Ramsbottom carbon residue. 4.2 Provision is made for determining the proper operating characteristics of the furnace with a control bulb containing a thermocouple, which must give a specified time-temperature relationship.

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5. Significance and Use 5.1 The carbon residue value of burner fuel serves as a rough approximation of the tendency of the fuel to form deposits in vaporizing pot-type and sleeve-type burners. Similarly, provided alkyl nitrates are absent (or if present, provided the test is performed on the base fuel without additive) the carbon residue of diesel fuel correlates approximately with combustion chamber deposits. 5.2 The carbon residue value of motor oil, while at one time regarded as indicative of the amount of carbonaceous deposits a motor oil would form in the combustion chamber of an engine, is now considered to be of doubtful significance due to the presence of additives in many oils. For example, an ash-forming detergent additive can increase the carbon residue value of an oil yet will generally reduce its tendency to form deposits. 5.3 The carbon residue value of gas oil is useful as a guide in the manufacture of gas from gas oil, while carbon residue values of crude oil residuums, cylinder and bright stocks, are useful in the manufacture of lubricants.

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NOTE" OXIDIZEOONTROLBULB BY HEATING IN FUNNA¢~[ TO TEMPERATU~ 9 0 0 O c FOR 30 MIN.

TOTAL WEIGHT OF OOHTROLBULB LESS THERMODOUPLEEOUALB ~4~ 18. TOLE RANC[ t"--0.4 ON ALL FRACT|QNAL OIMENSIONS

N O T E - - A l l dimensions are in millimetres.

FIG. 2

Control Bulb

furnace characteristics with the performance requirements (Section 7). The control bulb shall be provided with a dull finish, as specified in Fig. 2, and must not be polished thereafter. A polished bulb has different heating characteristics from one with a dull finish. A suitable thermocouple pyrometer for observing true temperature within + 1°C is also required. 6.3 Sample Charging Syringe, 5 or 10-mL glass hypodermic (Note 4), fitted with a No. 17 needle (1.5 m m in outside diameter) or No. 0 serum needle (1.45 to 1.47 m m in outside diameter) for transfer of the sample to the glass coking bulb. NOTE 4~A syringe having a needle that fits on the ground-glass tip of the syringeis not recommended, as it may be blown offwhen pressure is applied to the syringe plunger. The Luer-Lok type syringes are more satisfactory, as the needle locks on the bottom of the syringebarrel, and cannot be blown off by pressure. 6.4 Metal Coking Furnace of solid metal, having coking bulb wells 25.45 +_ 0.1 m m in internal diameter and 76 m m deep to the center of the well bottom, with suitable arrangements for heating to a uniform temperature of 550°C. The bottom of the well shall be hemispherical to accommodate the bottom of the glass coking bulb. Do not cast or otherwise form the furnace with unnecessary voids which will impede heat transfer. If a molten metal furnace is used, provide it with a suitable number of bulb wells, the internal dimensions of which correspond to the internal dimensions of holes in the solid metal furnace. The bulb wells shall be immersed in the molten metal to leave not more than 3 m m of the bulb well exposed above the molten metal at operating temperatures.

I

24=2 = _ 2 _ 5 2 _ _ WALL APPROX 1"4

HEMISPHERICAL INSIDf="RAD 1I APPROX

NOTE 5--Ramsbottom coke furnaces now in use can have dimensional differences from those given in 6.4; however, it is essential that new furnaces obtained after the adoption of this test method conform to the requirements outlined in 6.4. A description of one type of furnace which has been found to be satisfactoryis given in Appendix Xl.

N O T E ~ A l l dimensions are in millimetres.

FIG. 1

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~GEHAMIC; INSULATOR 445~.GO.BV 63.5 LONG WITH TWO HOLLO LeSmmOlAId.

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6.1 Glass Coking Bulb, of heat-resistant glass conforming to the dimensions and tolerances shown in Fig. 1. Prior to use, check the diameter of the capillary to see that the opening is greater than 1.5 and not more than 2.0 ram. Pass a 1.5-ram diameter drill rod through the capillary and into the bulb; attempt to pass a 2.0-ram diameter drill rod through the capillary. Reject bulbs that do not permit the insertion of the smaller rod and those whose capillaries are larger than the larger rod. 6.2 Control Bulb, stainless steel, containing a thermocouple and conforming to the dimensions and tolerances shown in Fig. 2, for use in determining compliance of

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t~) D 524 6.5 Temperature-Measuring Devices--A removable ironconstantan thermocouple with a sensitive pyrometer, or other suitable temperature-indicating device, located centrally near the bottom portion of the furnace and arranged to measure the temperature of the furnace so that the performance tests specified in Section 7 can be obtained. It is desirable to protect the temperature-indicating device with a quartz or thin metal sheath when a molten bath is used.

when only a tingle test is made. Inspect each well in similar fashion with the furnace singly loaded each time. NOTE 8--It is possible that not all of the wells in old furnaces will meet the requirements when fully loaded and tingly loaded; and, when this is the case, inspect each well for any degree of furnace loadingwhich may be used. For example, when not more than three wells of a six-well furnace can be used at any one time, the three wells to be used should be chosen from the performancedata obtained with fully loaded and singly loaded furnaces. Then each of the three wells should be inspected for triple loadinp~ two of the wells for double loading, and one for single loading. Use the wells tested and no others in applying the test procedure. NOTE 9--In sampling oils containing sediment (for example, used oils), it is important to make the transfer of sample in the shortest possible time to avoid segregation of the sediment. Samples containing sediment which settles quickly after stirring can be placed in the coking bulbs more expeditouslyby using an arrangement such as that shown in Fig. 3. This sampling device consists of a three-way 2-ram stopcock to which have been fused two lengths of capillary tubing (1.5 mm in inside diameter). Connect the third leg of the stopcock by means of pressure tubing to a vacuum line. Secure the glass coking bulb to the short arm of capillary tubing by a 25-mm length of rubber hose, taking care that the capillary of the glass bulb is butted up against the capillary tubing. Immerse the long end of the capillary tubing in the sample. After evacuating the cokingbulb, manipulate the stopcock to causethe stirred sample to flow freely into the bulb through the two lengths of capillary tubing. It is necessaryto use tubing with the same size capillaryas that in the neck of the coking bulb to prevent accumulation of any sediment during transfer.

NOTE 6 - - I t is good practice to calibrate the thermocouple or other

temperature-measuring device against a standard thermocouple or reference standards about once a week, when the furnace is in constant use, the actual frequency depending on experience.

7. Checking Performance of Apparatus 7.1 Periodically check the performance of the furnace and temperature-measuring devices as described in 7.1.1, 7.1.2, and 7.1.3 to make certain that as used they conform to the requirements of the method. Consider the furnace as having standard performance, and use it with any degree of loading, when the operating requirements described for each coking bulb well are met, while the bath is fully loaded as well as singly loaded. Use only a furnace that has successfully passed the performance or control tests given in this section. 7.1.1 Thermocouple--At least once every 50 h of use of the control bulb, calibrate the thermocouple in the control bulb against a standard thermocouple.

8. Sampling

NOTE 7 - - I n use at the high temperature of the test, iron-constantan thermocouples oxidize and their calibration curves change.

8.1 For sampling techniques see Practice D 4057 or Practice D 4177.

7.1.2 Fully Loaded Furnace--When the furnace temperature is within a previously chosen 2"C temperature range (which range is to be used thereafter with that particular furnace for both standardization and routine operation) and within the general range 550 + 5"C, insert the control bulb in one well and, within 15 s, insert in each of the other wells a glass coking bulb containing 4 _ 0.1 g of a viscous neutral petroleum lubricating oil with a viscosity within the SAE 30 range or 60 to 100 mm2/s (cSt) at 40"C. With a suitably accurate potentiometer or millivoltmeter (sensitive to I*C or less), observe the temperature rise in the control bulb at l-min intervals for 20 min. If the temperature in the control bulb reaches 547"C in not less than 4 and not more than 6 min from the instant of its insertion in the furnace, and remains within the range 550 ___ 3"C for the remaining portion of the 20-min test, consider that particular coking bulb well suitable for use as a standard performance well when the furnace is used fully loaded. Inspect each well in similar fashion with the furnace fully loaded each time. 7.1.3 Singly Loaded Furnace--When the furnace temperature is within a previously chosen 2"C temperature range (which range is to be used thereafter with that particular furnace for both standardization and routine operation) and within the general range 550 __. 5"C, insert the control bulb in one well, with the remaining wells unoccupied. With a suitably accurate potentiometer or millivoltmeter (sensitive to I*C or less), observe the temperature rise in the control bulb at l-rain intervals for 20 min. If the temperature in the control bulb reaches 547"C in not less than 4 and not more than 6 min from the instant of its insertion in the furnace, and remains within the range 550 + 3"C for the remaining portion of the 20-min test, consider that particular coking bulb well suitable for use as a standard performance well

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D 524 with a piece of sized paper or camels' hair brush. Weigh to the nearest 0.1 mg. Discard the used glass coking bulb.

9. Procedure 9.1 Place a new glass coking bulb (Note 11) in the coking furnace at 5500C for about 20 min to decompose any foreign organic matter and to remove water. Place in a closed desiccator over CaCI2 for 20 to 30 min and then weigh to the nearest 0.1 mg.

NOTE 13--In studies of oil characteristics, useful information can often be gleaned from a simple visual examination of the coking bulb

after the test. Thus, significance can be attached to noting, with the results, such findings as: coke more or less fills the bulb; fiquid material is present, either as limpid residue or drops; the residue is not black and flaky, but is colored and pulverulent (presumably from presence of inorganic materials).

NOTE 10--Do not re-use a glass coking bulb, as unpredictable results are sometimes obtained in such cases. For routine testing, new bulbs can be used without pre-ignition provided they are visibly free from particles or other contamination. Such bulbs, at least, should be heated in a n oven to 150"C, placed in a desiccator, and then weighed. NOTE 11--On making a test, it is important to adhere rigorously t o the temperature conditions chosen for Checking Performance of Apparatus (Section 7); for example, if the bath was at a temperature of 553 ±

10. Special Procedure 10.1 Test on 10 % Distillation Residue--This procedure is applicable to light distillate oils such as ASTM Nos. 1 and 2 fuel oils. 10.1.1 Assemble the distillation apparatus described in Specification E 133 using flask D (250-mL bulb volume), flask support board with 51-mm diameter opening, and graduated cylinder C (200-mL capacity). A thermometer is not required but the use of the ASTM High Distillation Thermometer 8F or 8C as prescribed in Specification E 1 or of the IP High Distillation Thermometer 6C, as prescribed in the IP Thermometer Specification, is recommended. 10.1.2 Place a volume of sample equivalent to 200 m L at 13 to 18"C in the flask. Maintain the condenser bath at 0 to 4"C (for some oils it may be necessary to hold the temperature between 38 and 60"C to avoid solidification of waxy material in the condenser tube). Use, without cleaning, the cylinder from which the sample was measured as the receiver and place it so that the tip of the condenser does not touch the wall of the cylinder. 10.1.3 Apply heat to the flask at a uniform rate so regulated that the first drop of condensate exits from the condenser 10 to 15 min after initial application of heat. After the first drop falls, move the receiving cylinder so that the tip of the condenser tube touches the wall of the cylinder. Then regulate the heat so that the distillation proceeds at a uniform rate of 8 to 10 mL/min. Continue the distillation until 178 m L of distillate has been collected, then discontinue heating and allow the condenser to drain until 180 m L (90 % of the charge to the flask) has been collected in the cylinder. 10.1.4 Immediately replace the cylinder with a small Erlenmeyer flask and catch any final drainage in the flask. Add to this flask, while still warm, the residue left in the distilling flask, and mix well. The contents of the flask then represent a 10 % distillation residue from the original product. 10.1.5 While the distillation residue is warm enough to flow freely, place 4.0 + 0.1 g of it into the previously weighed coking bulb. A hypodermic syringe provides a convenient means of performing this operation. After cooling, weigh the bulb and contents to the nearest 1 rag, and carry out the carbon residue test in accordance with the procedure described in Section 7. 10.1.6 Report the percentage of carbon residue as the Ramsbottom carbon residue on 10 % distillation residue.

I*C when inserting the control bulb, then it is necessary to use similar temperature conditions in the coking test. When maintained in normal operation, the temperature of an electrically heated furnace with automatic controls will generally fluctuate within a specific temperature range. Therefore, when making a coking test, it is generally important that the test bulbs be inserted when the furnace is at the same temperature or at the same position in the temperature cycle as it was when the inspection test was started, unless it has been proven that the temperature variations are inappreciable. 9.2 Shake thoroughly the sample to be tested, first heating to 50 ° _ 10°C for 0.5 h when necessary to reduce its viscosity. Immediately following the heating and shaking, strain the sample through a 100-mesh wire screen. By means of a hypodermic syringe or the device shown in Fig. 3 introduce into the coking bulb an amount of sample as indicated in Table 1. Make sure that no oil remains on the exterior surface or on the inside of the neck of the bulb. Reweigh the bulb and contents to the nearest milligram. If the sample foams or spatters, repeat the test using the next smaller sample size listed in Table 1. In reporting the results, include the size when such small samples are used. If difficulty is encountered in loading very viscous or asphaltic samples of any size into the glass coking bulb, the apparatus shown in Fig. X 1.2 can be used. 9.3 Place the coking bulb in a standard performance well with the furnace at the checking temperature (Note 11), and allow to remain for 20 + 2 min. Remove the bulb with metal tongs, the tips of which have just been heated. Duplicate the furnace and bulb conditions used when standardizing that bulb well (Section 7 and Note 8). If there is appreciable loss of oil from frothing, discard the test and repeat the determination using a smaller sample (Note 12). NOTE 12--Frothing can be due to water which can be removed by

heating gently in a vacuum and sweeping out the vapor with nitrogen prior to filling the bulb. 9.4 After removal, cool the bulb in a desiccator under the same conditions (including time for weighing) used before filling the bulb (9.2). When removing the bulb from the desiccator, examine it to make sure there are no foreign particles adhering to the bulb; if any are found, as black particles sometimes are on the capillary neck, brush them off TABLE 1

Sample Sizes

Ramsbottom Carbon Residue, % Less than 6.0 6.0 to 14.0 14.1 to 20.0

11. Calculation and Report 11.1 Calculate the carbon residue of the sample or of the 10 % distillation residue as follows: Carbon residue = (A x 100)/W (1)

Sample Size, g 4.0:1:0.1 1.0 + 0.1 0.5 + 0.1

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RAI~SBOTI'OMCARBONRESIDUE,AVERAGEPER CENT NOTE--Log n ffi 1.069 + 0.752 log x + 0.237 (log x)~ Log R ffi 0.853 + 0.789 log x + 0.190 (log x f x = avera0e of results t ~ o g compared FIG. 4

Precision

where: A = mass of carbon residue, g, and W ffi mass of sample, g.

Data

test material would, in the long run, in the normal and correct operation of the test method, exceed the values shown in Fig. 4 only in one case in twenty. 12.1.2 Reproducibility--The difference between two single and independent results obtained by different operatots working in different laboratories on identical test material would, in the long run, in the normal and correct operation of the test method, exceed the values shown in Fig. 4 only in one case in twenty.

11.2 Report the value obtained as Ramsbottom carbon residue, percent or as Ramsbottom carbon residue on 10 % distillation residue, percent. 12. Precision and Bias 6 12.1 The precision of this test method as determined by statistical examination of interlaboratory results is as follows: 12.1.1 Repeatability--The difference between two test results, obtained by the same operator with the same apparatus under constant operating conditions on identical

NOTE 14---Precision is based on data developed using inch-pound units. See Test Method D 524. 12.2 Bias--This test method is empirical and no statement of bias can be made. 13. Keywords 13.1 carbon residue; petroleum products; ramsbottom

6 Supporting data are available from ASTM Headquarters. Request RR: D02-1228.

148

(6~')D 5 2 4 APPENDIXES

(Nonmandatory Information) Xl.

R A M S B O T r O M COKING FURNACE

X 1.1 The greatest difficulty in achieving satisfactory precision for this test method is to obtain a uniformly operating furnace. The type of furnace described below meets the performance characteristics prescribed in Section 7. XI.2 Solid Metal FurnaceTmA solid metal furnace can be constructed as illustrated in Fig. X1.1. It can be constructed of cast iron or other suitable metal for use under the high-temperature conditions which are employed in this test method. It is desirable to cast the metal without any unnecessary voids. Use of a substantial mass of metal for the block avoids the requirement for an excessive amount of electrical heating which could cause wide fluctuations in block temperature unless very sensitive controls were used. X 1.3 Coking Bulb Filling Device--The glass coking bulb filling device as shown in Fig. X1.2 has been found satisfacThe sole source of supply of the apparatus known to the committee at this time is Preci~on Scientific Co., 3737 W. Cortland St., Chicago, I L 60647. If you are aware of alternative suppliers, please provide this information to ASTM Headquarter~ Your comments will receive careful consideration at a meeting of the responsible technical committee, ~ which you m a y attend.

tory for use with any mobile liquids that are too viscous to be handled at room temperature. The illustrated stand is made of 3 m m brass plate and constructed to hold five 10-mL syringes. For convenience, the stand can be modified to hold any number of syringes of either the 5 or 10-mL type. XI.3.1 Warm the sample to be tested until it is fluid, place a coking bulb in position under the syringe and remove the plunger of the syringe from the barrel. Pour a representative portion of the sample into the barrel of the syringe, lubricate the plunger with one or two drops of white oil and replace in the barrel. Then place the loaded syringe in the rack as shown, with the spring-loaded clip fitted over the plunger head and with the tip of the needle extending into the bulb. Place the entire assembly in an oven maintained at the lowest temperature that will permit the sample to flow sufficiently to load the bulb. X1.3.2 As soon as sufficient sample has been forced into the coking bulb, remove and weigh the bulb and its contents and proceed as described in 9.3 of this test method. Remove the assembled apparatus from the oven as soon as possible as extended heating periods may alter the carbon residue value of the sample.

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CONRADSON CARBON RESIDUE, PER CENT BY MASS (ASTM D 189) NOTE--All dimensions are in millirnetres.

FIG. X1.1 SolidMetal Furnace

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FIG. X1.2 CokingBulb Filling Device X2. INFORMATION CONCERNING CORRELATION OF CARBON RESIDUE RESULTS DETERMINED BY THE TWO TEST METHODS, D 189 AND D 524

X2.1 No exact correlation of the results obtained by the two test methods exists because of the empirical nature of the two tests. However, an approximate correlation (Fig. X2. l) has been derived from the cooperative testing by ASTM Committee D-2 of 18 representative petroleum products and confirmed by further data on about 150 samples which were

not tested cooperatively. Test results by both test methods on unusual types of petroleum products may not fall near the correlation line of Fig. X2.1. X2.2 Caution should be exercised in the application of this relation to samples of low carbon residues.

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The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reepproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you should make yOur views known to the ASTM Committee on Standards, 100 Barr Harbor DrNe, West Conshohecken, PA 19428.

151

Designation: D 611 - 82 (Reapproved 1993) E1

®

An American National Standard

Designation: 2/84

Standard Test Methods for Aniline Point and Mixed Aniline Point of Petroleum Products and Hydrocarbon Solvents 1 This standard is issued under the fixed designation D 61 I; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last rcapproval. A superscript epsilon (~) indicates an editorial change since the last revision or reapproval.

These test methods were adopted as a joint ASTM-IP standard in 1964. These test methods have been approved for use by agencies of the Department of Defense and for listing in the DoD Index of Specifications and Standards. ~l NorE--Keywords were added in May 1993.

D 1218 Test Method for Refractive Index and Refractive Dispersion of Hydrocarbon Liquids2 D 1500 Test Method for ASTM Color of Petroleum Products (ASTM Color Scale)2 D 2700 Test Method for Knock Characteristics of Motor and Aviation Fuels by the Motor Method 3 E 1 Specification for ASTM Thermometers4

1. Scope 1.1 These test methods cover the determination of the aniline point of petroleum products and hydrocarbon solvents. Method A is suitable for transparent samples with an initial boiling point above room temperature and where the aniline point is below the bubble point and above the solidification point of the aniline-sample mixture. Method B, a thin-film method, is suitable for samples too dark for testing by Method A. Methods C and D are for samples that may vaporize appreciably at the aniline point. Method D is particularly suitable where only small quantities of sample are available. Method E describes a procedure using an automatic apparatus suitable for the range covered by Methods A and B. 1.2 These test methods also cover the determination of the mixed aniline point of petroleum products and hydrocarbon solvents having aniline points below the temperature at which aniline will crystallize from the aniline-sample mixture. 1.3 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Specific precautionary statements are given in Sections 7.1 and 7.3.

3. Terminology 3.1 Definitions: 3.1.1 aniline point--the minimum equilibrium solution temperature for equal volumes of aniline and sample. 3.1.2 mixed aniline point--the minimum equilibrium solution temperature of a mixture of two volumes of aniline, one volume of sample, and one volume of n-heptane of specified purity. 4. Summary of Test Methods 4. I Specified volumes of aniline and sample, or aniline and sample plus n-heptane, are placed in a tube and mixed mechanically. The mixture is heated at a controlled rate until the two phases become miscible. The mixture is then cooled at a controlled rate and the temperature at which two phases separate is recorded as the aniline point or mixed aniline point. 5. Significance and Use 5.1 The aniline point (or mixed aniline point) is useful as an aid in the characterization of pure hydrocarbons and in the analysis of hydrocarbon mixtures. Aromatic hydrocarbons exhibit the lowest, and paraffins the highest values. Cycloparaffins and olefins exhibit values that lie between those for paraffins and aromatics. In homologous series the aniline points increase with increasing molecular weight. Although it occasionally is used in combination with other physical properties in correlative methods for hydrocarbon analysis, the aniline point is most often used to provide an

2. Referenced Documents

2.1 A S T M Standards: D 1015 Test Method for Freezing Points of High-Purity Hydrocarbons2 D 1217 Test Method for Density and Relative Density (Specifc Gravity) of Liquids by Bingham Pycnometer2 These test methods are under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and are the direct responsibility of 1302.04 on Hydrocarbon Analysis. Current edition approved Aug. 27, 1982. Published January 1983. Originally published as D 611 - 41 T. Last previous edition D 611 - 77. 2 Annual Book of ASTM Standards, Vol 05.01.

s Annual Book of ASTM Standards, Vo105.04. 4 Annual Book of ASTM Standards, Vols 05.03 and 14.03.

152

~l[l~ D611 TABLE 1

Requirements for n - H e p t a n e

4- 0.4"17) as determined from the average of two independent tests having a difference of not more than 0. I'C (0.2*F). NOTE 3: Warning:Aniline should not be pipetted directly by mouth because of its extreme toxicity. Aniline is also toxic by absorption through the skin even in verysmall quantities, and should be handled with great caution. NOTE4--For routine purposes the distillation process is not mandatory provided the aniline meets the requirements of the test with n-heptane. NOTE 5--The aniline point ofaniline and n-heptane determined with automatic apparatus (Method E) shall be 69.3 + 0.2"C (! 56.7"F :t: 0.4"1=) when corrected in accordance with the equation in Section A5.2.1. NOT~ 6--As an alternative to distilling the aniline on the day of use, the aniline may be distilled as described in 7.1, collectingthe distillate in ampoules, sealing the ampoules under vacuum or dry nitrogen, and storing in a cool dark place for future use. In either case, rigid precaution must be taken to avoid contamination from atmospheric moisture (Note 2). It is believed that under these conditions the aniline will remain unchanged for a period exceeding 6 months.

ASTM Method ASTM Motor Octane Number Density at 20"C, g/mL Refractive index, no =°'c Freezing point, *C 1Distillation, 50*'-, recovered at 1.013 bar (760 mm Hg), *C Differential, 80 • recovered minus 20 Yorecovered, *C

0.0 0.68380 1.38770 -90.710 98.427

± 0.2 ± 0.00015 ± 0.00015 min ± 0.025

D 2700 D 1217 D 1218 D 1015 A

0.020 max

A For equipment and method used, see Journal of Research, Nat. Bureau Standards, Vol 44, No. 3, 1950, pp. 309 and 310 (RP2079). 1" Editorially corrected.

estimate of the aromatic hydrocarbon content of mixtures. 6. Apparatus 6.1 For details of the aniline point apparatus required for each method see: Annex A1 for Method A Annex A2 for Method B Annex A3 for Method C Annex A4 for Method D Annex A5 for Method E NOTE l--Alternative apparatus may be used, such as the U-tube method for dark oils, provided it has been shown to give results of the same precision and accuracy as those described in the Annexes.

7.2 Calcium Sulfate, anhydrous. 7.3 n-Heptane (Warning--See Note 7.), conforming to the requirements listed in Table 1.5 NOTE 7--Warning--Flammable. Harmful if inhaled. See Annex A6.1.

8. Sample 8.1 Dry the sample by shaking vigorously for 3 to 5 min with about 10 volume % of a suitable drying agent such as anhydrous calcium sulfate or anhydrous sodium sulfate. Reduce the viscosity of viscous samples by warming to a temperature below that which would cause the loss of light ends or the dehydration of the dryiffg agent. Remove any suspended drying agent by use of a centrifuge or by filtration. Heat samples containing separated wax until they are homogeneous and keep heated during filtration or centrifugation to ensure against separation of wax. When suspended water is visibly present and the sample material is known to dissolve less than 0.03 mass % of water, the use of a centrifuge for the removal of suspended water is an acceptable procedure.

6.2 Heating and Cooling Bath--A suitable air bath, a nonvolatile, transparent liquid bath, or an infrared lamp (250 to 375 W), provided with means for controlling the rate of heating. NOTE 2--Water should not be used as either a heating or cooling medium since aniline is hygroscopic and moist aniline will give erroneous test results. For example, the aniline point of the n-heptane reagent as measured with aniline containing 0.1 volume % water is approximately0.5"C (0.9"F) higher than that measured with dry aniline. If the aniline point is below the dew point of the atmosphere, pass a slow stream of dry inert gas into the aniline point tube to blanket the aniline-sample mixture. 6.3 Thermometers, having the following ranges and conforming to the requirements of the designated ASTM or IP specification: Range - 3 8 to +42"C (-36.5 to +107.5"F) 25 to 105"C (77 to 221"F) 90 to 170"C (194 to 338"F)

ASTM (Specification E 1) 33C, 33F 34C, 34F 35C, 35F

9.

Procedurefor Aniline Point

9.1 The following methods, to be used as applicable, are covered as follows: 9.1.1 Method A, described in detail in Annex A l, is applicable to clear samples or to samples not darker than No. 6.5 ASTM color, as determined by Test Method D 1500, having initial boiling points well above the expected aniline point. 9.1.2 Method R described in detail in Annex A2, is applicable to light-colored samples, moderately dark samples, and to very dark samples. It is suitable for samples that are too dark to be tested by Method A. 9.1.3 Method C, described in detail in Annex A3, is applicable to clear samples or to samples not darker than No. 6.5 ASTM color, as determined by Test Method D 1500, having initial boiling points sufficiently low as to give incorrect aniline point readings by Method A, for example, aviation gasoline.

IP 20C 21C 59C

6.4 Pipets, with capacities of 10 4- 0.04 mL, 5 + 0.02 mL, the latter equipped with a long, fine tip. Provide a rubber suction bulb for use with pipets when measuring aniline. 6.5 Balance--A laboratory balance sensitive to 0.01 g, suitable for weighing the tube and sample when the sample cannot be pipetted conveniently. 6.6 Safety Goggles. 6.7 Plastic Gloves, impervious to aniline.

7. Reagents 7.1 Aniline (Warning--See Note 3.) Dry chemically pure aniline over potassium hydroxide pellets, decant, and distill fresh on the day of use, discarding the first and last 10 %. Aniline thus prepared when tested with n-heptane according to Section 9 shall give an aniline point of 69.3 _ 0.2"C (156.7

These requirements for n-heptane are identical, except for tetraethyl lead, with those prescribed in the 1987Annual Book of ASTM Standards, Vol 05.04.

153

fl~ D611 9.1.4 Method D, described in detail in Annex A4, is applicable to the same type of sample as Method C. It is particularly useful when only limited quantities of sample are available. 9.1.5 Method E is applicable when using automatic apparatus in accordance with the instructions in Annex A5.

observations as described in Section 11) obtained by the same operator with the same apparatus under constant operating conditions on identical test material, would in the long run, in the normal and correct operation of the test method, exceed the following values only in one case in twenty: Repeatability

10. Procedure for Mixed Aniline Point

10.1 This procedure is applicable to samples having aniline points below the temperature at which aniline crystallizes from the mixture. Pipet 10 mL of aniline (Warning: See Note 3), 5 mL of sample, and 5 mL of n-heptane into a clean, dry apparatus. Determine the aniline point of the mixture by Method A or B as described in Annex A 1 or A2.

Aniline point of: Clear, light-colored samples Moderately dark to very dark samples Mixed aniline point of: Clear, light-colored samples Moderately dark to very dark samples

0.16"C (0.YF) 0.YC (0.6"F)" 0.16"C (0.YF) A 0.YC (0.6'F) A

A Not determined from recent cooperative tests; however, the ratios with those given in the 1953 version are believed to apply.

12.1.2 Reproducibility--The difference between two single and independent results, obtained by different operators, working in different laboratories on identical test material, would in the long run, in the normal and correct operation of the test method, exceed the following values only in one case in twenty: 12.2 B i a s u A statement of bias is now being developed by the subcommittee.

11. Report 11. I If the range of three successive observations of the aniline point temperature is not greater than 0. I'C (0.2"F) for light-colored samples or 0.2"C (O.4*F) for dark samples, report the average temperature of these observations, corrected for thermometer calibration errors, to the nearest 0.05"C (0. I'F) as the aniline point. 11.2 If such a range is not obtained aRer five observations, repeat the test using fresh quantities of aniline and sample in a clean, dry apparatus, and if consecutive temperature observations show a progressive change, or if the range of observations is greater than the repeatability given in 12.1, report the method as being inapplicable.

Reproducibility Aniline point of: Clear, light-colored samples Moderately dark to very dark samples Mixed aniline point of: Clear, light-colored samples Moderately dark to very dark samples

0.5"C(0.9"F) i.0"C(I.8"F)~ 0.7"c (i.3"F)-~ i.0"C(l.8"F)A

•¢ Not determined from recent cooperative tests; however, the ratios with those given in the 1953 version are believed to apply.

12.3 The precision of this test was not obtained in accordance with Committee D-2 Research Report RR:D021007, "Manual on Determining Precision Data for ASTM Methods on Petroleum Products and Lubricants. "4

12. Precision and Bias

12.1 The precision of these test methods as obtained by statistical examination of interlaboratory test results is as follows: 12. I. l Repeatability--The difference between successive test results (two average temperatures obtained in a series of

13. Keywords 13.1 aniline point; aromatics; mixed aniline point

ANNEXES (Mandatory Information) AI. METHOD A diameter shall be used as a guide for the stirrer. Any suitable mechanical device for operating the stirrer as specified is an approved alternative for the manual operation.

AI.1 Apparatus A I. 1.1 The apparatus shown in Fig. A 1.1 shall consist of the following: A I.I.I.I Test Tube, approximately 25 mm in diameter and 150 mm in length, made of heat-resistant glass. AI.I.I.2 Jacket, approximately 37 to 42 mm in diameter and 175 mm in length, made of heat-resistant glass. AI.I.I.3 Stirrer, manually operated, metal, approximately 2 mm in diameter (14 B&S gage) metal wire as shown in Fig. A 1.1. A concentric ring shall be at the bottom, having a diameter of approximately 19 mm. The length of the stirrer to a right-angle bend shall be approximately 200 ram. The right-angle bend shall be approximately 55 mm long. A glass sleeve approximately 65 mm in length of 3-mm inside

A1.2 Procedure AI.2.1 Clean and dry the apparatus. Pipet 10 mL of aniline (Warning--see 7.1) and 10 mL of the dried sample (8.1) into the test tube fitted with stirrer and thermometer. If the material is too viscous for pipetting, weigh to the nearest 0.01 g a quantity of the sample corresponding to 10 mL at room temperature. Center the thermometer in the test tube so that the immersion mark is at the liquid level, making sure that the thermometer bulb does not touch the side of the tube. Center the test tube in the jacket tube. Stir the mixture 154

t1~) D611

~

Anlllne Point Thermometer

<

Test

"rube-~ "4 A

175

Soft Iron Wiro---Jl~

as-I I

40--'.4

.

FIG. A1.1 AnilinePoint Apparatus rapidly using a 50-mm (2-in.) stroke, avoiding the introduction of air bubbles. AI.2.2 If the aniline-sample mixture is not miscible at room temperature, apply heat directly to the jacket tube so that the temperature rises at a rate of I to 3"C (2 to 5*F)/min by removing or reducing the heat source until complete miscibility is obtained. Continue stirring and allow the mixture to cool at a rate of 0.5 to 1.0*C (1.0 to 1.8*F)/min. Continue cooling to a temperature of I to 2"C (2.0 to 3.5"F) below the first appearance of turbidity, and record as the aniline point the temperature at which the mixture suddenly

All Dimensions In Milllmetres

I

(Method

A)

becomes cloudy throughout (Note A 1.1). This temperature, and not the temperature of separation of small amounts of material, is the minimum equilibrium solution temperature. Note A l.l--The true aniline point is characterized by a turbidity that is so cloudyas to obscurethe thermometer bulb in reflected light. A1.2.3 If the aniline-sample mixture is completely miscible at room temperature, substitute a non-aqueous cooling bath for the heating source, allow to cool at the rate specified in AI.2.2, and determine the aniline point as described. AI.2.4 Repeat the observation of aniline point temperature by heating and cooling repeatedly until a report as directed in Section 11 can be made.

A2. METHOD B of the aniline point. Adjust the voltage on the lamp until just enough light is given for the filament to be visible through the film. Raise the temperature of the mixture at a rate of 1 to 2"C (2.0 to 3.5*F)/min until the aniline point has just been passed, as denoted by a definite, sudden brightening of the lamp filament, and by the disappearance of the more or less opalescent condition of the fdm (Note A2.1). Discontinue heating and adjust the lamp voltage so that the filament appears clear and distinct but not uncomfortably bright to the eye. Adjust the temperature of the bath so that the sample-aniline mixture cools at a rate of 0.5 to 1.0*C (1.0 to 1.8"F)/min and note the appearance of the film and light filament. Record as the aniline point the temperature at which a second phase appears as evidenced by the reappearance of the opalescent condition of the film (usually causing a halo to appear around the lamp filament) or by a sudden dimming of the lamp filament, or both. At temperatures above the aniline point the edges of the light filament appear clear and distinct. At the aniline point temperature a halo or haze forms around the filament, replacing the distinct lines of the filament edge with lines that appear cloudy or hazy in appearance. Further darkening of the cloud over the filament

A2.1 Apparatus A2.1.1 Thin-FilmApparatus, made of heat-resistant glass and stainless steel, conforming to the dimensions given in Fig. A2.1. A suggested assembly is shown in Fig. A2.2. A2.2 Procedure A2.2.1 Clean and dry the apparatus. Pipet 10 mL of aniline (Warning--see Note 3) and 10 mL of the dried sample (8.1) into the tube fitted with pump-stirrer and thermometer. If the material is too viscous for pipetting, weigh to the nearest 0.01 g a quantity of sample corresponding to 10 mL at room temperature. Place the thermometer in the tube so that the contraction chamber is below the liquid level and so that the mercury bulb does not touch the side of the tube. Assemble the apparatus as shown in Fig. A2.2. A2.2.2 Adjust the speed of the pump to produce a continuous stream of the oil-aniline mixture in the form of a thin film flowing over the light well. With extremely dark oils, operate the pump slowly and lower it so that the delivery tube nearly touches the top of the light well, so as to obtain a continuous film thin enough to permit observation 155

~) D 611 T Grind Two Parallel Flats To O.D.Of TubeSquareWith Axis Of Tube. Precision BoreGlass ~ I 4 Dio. Stainless Tubing. Lop ToRunning ~ l q --,.I I U Sta'l Rod. Fit On PumpRotor,

I ~-~40 Dia.--

14~ -+2 1 230~5

i -31-+1 I.D.

100±2

Hole, 2 DiD.Through One Wall Only

iso.~5

S~!T~2

,--IO To II l

--- 11.5~0.3 I.D.

~"3 Dia. 2

5

I

5

~- 2 Die.

/

•

75!2

~FLeft HandThread Fr~ PitchEquals2/cm 5.2 Wide0.8 Deep,4 O.O.I~j)pod To Fit PumpBody.

~ oil GrindJ

All Dimensions In Millimeters DETAIL OF TUBE FIG. A2.1

Pump Rotor StainlessSteel 6.5 xO.Sx12.5Notch For 2.4 DiD.Shaft. Twist And Weld Using18-8WeldingRod. DETAIL OF PUMPBODYAND ROTOR

Details of Aniline Point Thin-Film Apparatus (Method B)

[ ":

t~ !T1 , ~

!H

AJrSt,rr,n¢ Motor

;}1'

Bok.li,. Cov.r

I ~ ~ and Support ~ S p r i n ( ~ l Clips Holdino ~ - ~ ) j ~ l l l l l l ~ ~- -Aniline Point Tube in oc,

~ ' ~ ~ -- Panel Lamp P I~ ~i',~W'ii~/[l~'~ Pump"Stirrer IH

~ FIG. A2.2

to o-8 vo,s

Oil Both

Assembly of Thin-Film Apparatus (Method B)

the aniline point, to the translucent state below. If the sample is such that there is difficulty in observing the exact point of the phase change, make experiments with the sample, using various intensities of light and paying particular attention to the appearance of the light in the immediate vicinity of the lamp fdament. A2.2.3 Repeat the observation of aniline point temperature by heating and cooling repeatedly until a report as directed in Section 11 can be made.

occurs at lower temperature, but is n o t to be confused with

the aniline point. NOTE A2.l--For those making the test for the first time, the following procedure may be helpful: Make preliminary operational adjustments and tests using a colorless sample-aniline mixture, and observing changes taking place in the body of the liquid and fdm. Make rough tests with dark oils to become familiar with the appearance of the film and light source as the mixture passes from the clear state above

156

~

D611

A3. METHOD C tube; the tube contains sufficient light transformer oil to cover the bulb of the thermometer. The inner tube is held in the top of the aniline-point tube by a tightly fitting stopper, and a clamp is provided to hold the stopper in position to prevent loss of vapor from the sample. NOTE A3.1mAny other suitable arrangement, such as a screwed plastic gland carrying the thermometer, that will prevent the loss of vapor from the apparatus, may be used. In such casesit may be possible to omit the thermometertube and immersethe thermometerbulb in the aniline-samplemixture. A3.1.2 Guard, of stout metal gauze and surrounding the aniline point tube. It should preferably be combined with the clamp for holding the thermometer tube in place.

A3.1 Apparatus A3. I. 1 Aniline-Point Tube, of heat-resistant glass, of the shape and dimensions shown in Fig. A3.1, and fitted internally with a thin-walled glass thermometer tube, sealed at the lower end. The latter tube accommodates a tightfitting cork stopper carrying the thermometer, the bulb of which rests on a cork ring or disk placed at the bottom of the

14Dlo.

A3.2 Procedure A3.2. l Clean and dry the apparatus. Pipet 5 mL of aniline (Note A3.2 Precaution see Note 3) and 5 mL of the dried sample (8.1), both cooled to a temperature at which the sample may be measured without loss of vapor. Close the tube by means of the stopper and fit the thermometer tube centrally so that the bottom is 5 mm from the bottom of the aniline point tube. Clamp the stopper in position and attach the guard. NOTE A3.2: Precaution--Put on gogglesof safety glass and plastic gloves imperviousto aniline. A3.2.2 Follow the procedure described in AI.2.2 and A1.2.3 but mix the sample and aniline by shaking the tube. If the rate of change of temperature is greater than l'C (2°F)/min when the aniline point is being approached, place the tube in a jacket that has previously been warmed or cooled to an appropriate temperature. A3.2.3 Repeat the observation of aniline point by heating and cooling repeatedly until a report as directed in Section I l can be made.

~r.~p--,----- 9 Dia. 150

I

I

y II L"

i1,, ~.,~Aflillnl

01o-4

Point Tube

,,, Oim.n.,on. in M,,o.,..

FIG. A3.1 Apparatusfor VolatileSamples(Method C)

A4. METHOD D

A4.1 Apparatus A4.1.1 Bulb, 1.5 to 2.0-mL capacity, blown from heatresistant glass tubing, 5 mm in external diameter and 3 mm in internal diameter. A4.1.2 Guard, as for Method C.

thoroughly and rapidly draw out and seal the open end of the bulb at about l0 mm from the center of the bulb. NOTE A4.1: Precaution--Put on gogglesof safetyglass and plastic gloves imperviousto aniline. A4.2.2 Attach the bulb to the thermometer by rubber bands so that the bulb is adjacent to the thermometer bulb. Attach the mesh guard and follow the procedure described in A1.2.2 and AI.2.3 but mix the sample and aniline by shaking. A4.2.3 Repeat the observation of aniline point temperature by heating and cooling repeatedly until a report as directed in Section l I can be made.

A4.2 Procedure A4.2.1 Dry the bulb thoroughly in an oven at 105 + 5°C, allow it to cool to room temperature, and charge it by means of the pipets with 0.5 mL of aniline (Warning--see Note 3) and 0.5 mL of the dried sample (8.1). Cool the mixture

157

q~ D611 A5. M E T H O D E or more samples with aniline points in each of the ranges 43 to 49"C (110 to 120*F), 60 to 66"C (140 to 150*F), and 77 to 82"C (170 to 180*F). Calculate the constants A and B by the least squares method by simultaneous solution of the following equations: Z(Xa) = N A + BZ(Xc) ~(x, xc) = A~(Xc) + B~.(X))

A5.1 Apparatus

A5.1.1 A u t o m a t i c A n i l i n e P o i n t A p p a r a t u s , commercially available, using a modified thin film technique and direct heating of the sample-aniline mixture with electrical immersion heater. Detection of change of sample turbidity at the aniline point is by response of a photoelectric cell to collimated light directed through the thin film of sample.

where: Y~(Xa)

A5.2 Procedure A5.2.1 Determine the automatic aniline point in accordance with instructions provided with the apparatus. Correct the aniline point as follows: Corrected aniline point = ( X a - A ) / B

sum of all aniline point data by automatic apparatus, Z(Xc) = sum ofaU aniline point data by either Method A or B, Z(X~) = sum of the squares ofaU aniline point data by either Method A or B, Z(X~Xc) = sum of the products of aniline points determined by either Method A or B and by using the automatic apparatus for each sample, and N = number of samples. Note A5.2--Cooperative data were obtained from five laboratories for five samples with aniline points in the range from 34 to 87"C (93 to 188"F). Constants A and B were calculated for the composite data as 0.79 and 0.991 respectively. Although a minimum number of nine samples is specifiedin this method, constants A and B in the preceding equation may be obtained with a slightlygreater precision if data for a larger number of samples are used.

where:

x.

ffi automatic aniline point, and A and B ffi constants determined for each apparatus as described in A5.2.2. NOTE A5. l--lt has been established by cooperative tests that observed aniline points determined by some automatic apparatusare lower than the determinations by Methods A and B. The difference is greater for automatic apparatus when relatively high sample-cooling rates are used, and increases as the aniline point increases. A5.2.2 Determine the aniline point by either Method A or Method B and also using the automatic apparatus for three

ffi

A6. PRECAUTIONARY S T A T E M E N T Use with adequate ventilation. Avoid prolonged breathing Of vapor or spray mist. Avoid prolonged or repeated skin contact.

A6.1 n-Heptane

Warning--Flammable. Harmful if inhaled. Keep away from heat, sparks, and open flame. Keep container closed.

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned In this standard Users of this standard are expressly advised that determination of the vahdzty of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is sublect to revision at any time by the responsible technical committee and must be reviewed every hve years and if not revised, either reapproved or withdrawn Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 100 Barr Harbor Drive, West Conshohocken, PA 19428

158

Designation: D 664 - 95

IP@ Illl IN~l~llllF ~Jl pp IIUbg I l I M

An American National Standard Bdtish Standard 4457

Designation: 177/96

Standard Test Method for Acid Number of Petroleum Products by Potentiometric Titration 1 This standard is issued under the fixed designation D 664; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of Last re.approval. A superscript epsilon (0 indicates an editorial change since the last revision or reapproval. This test method was adopted as a joint ASTM-IP standard in 1964. This test method has been adopted for use by government agencies to replace Method 5106 of Federal Test Method Standard No. 791b. ASTM Test Method D 4739 has been developed as an alternative to the base number portion olD 664.

1. Scope 1.1 This test method covers procedures for the determination of acidic constituents in petroleum products and lubricants soluble or nearly soluble in mixtures of toluene and propan-2-ol (Note 1). It is applicable for the determination of acids whose dissociation constants in water are larger than 10-9; extremely weak acids whose dissociation constants are smaller than l0 -9 do not interfere. Salts react if their hydrolysis constants are larger than 10-9 .

D974 Test Method for Acid Color-Indicator Titration 2 D 1193 Specification for Reagent D3339 Test Method for Acid Products by Semi-Micro Color

and Base Number by Water 3 Number of Petroleum Indicator Titration 4

3. Terminology 3.1 Definitions: 3.1.1 acid number, n u t h e quantity of base, expressed as milligrams of potassium hydroxide per gram of sample, required to titrate a sample to a specified end point. 3. I. 1. l DiscussionuThis test method expresses the quantity of base as milligrams of potassium hydroxide per gram of sample, that is required to titrate a sample in the solvent from its initial meter reading in millivolts to a meter reading in miUivolts corresponding to a freshly prepared nonaqueous basic buffer solution or a well-defined inflection point as specified in the test method. 3. I. 1.2 Discussion--This test method provides additional information. The quantity of base, expressed as milligrams of potassium hydroxide per gram of sample, required to titrate a sample in the solvent from its initial meter reading in millivolts to a meter reading in miUivolts corresponding to a freshly prepared nonaqueous acidic buffer-solution or a well-defined inflection point as specified in the test method shall be reported as the strong acid number. 3.1.1.3 Discussion--The causes and effects of the socalled strong acids and the causes and effects of the other acids can be very significantly different. Therefore, the user of this test method shall differentiate and report the two, when they are found.

NOTE l m I n new and used oils, the constituents that may be

considered to have acidic characteristics include organic and inorganic acids, esters, phenolic compounds, lactones,resins, salts of heavy metals, salts of ammonia and other weak bases, acid salts of polybasicacids, and addition agents such as inhibitors and detergents. 1.2 The test method may be used to indicate relative changes that occur in an oil during use under oxidizing conditions regardless of the color or other properties of the resulting oil. Although the titration is made under definite equilibrium conditions, the test method is not intended to measure an absolute acidic property that can be used to predict performance of an oil under service conditions. No general relationship between bearing corrosion and acid number is known. NOTE 2--Tbe acid number obtained by this standard may or may not be numerically the same as that obtained in accordance with Test Methods D 974 and D 3339. 1.3 The values stated in acceptable SI units are to be regarded as the standard. 1.4 This standard does not purport to address all of the

safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

4. Summary of Test Method 4. I The sample is dissolved in a mixture of toluene and propan-2-ol containing a small amount of water and titrated potentiometrically with alcoholic potassium hydroxide using a glass indicating electrode and a calomel reference electrode. The meter readings are plotted manually or automatically

2. Referenced Documents 2.1 A S T M Standards: n This test method is under the jurisdiction of ASTM Committee D-2 o n Petroleum Products and Lubricants and is the direct responsibility of Subcommittee 1302.06 on Analysis of Lubricants. Current edition approved Oct. 10, 1995. Published December 1995. Originally published as D 664 - 42 T. Last previous edition D 664 - 89.

2 Annual Book of ASTM Standards, Vol 05.01. 3 Annual Book of ASTM Standards, Vol I 1.0 I. 4 Annual Book of ASTM Standards, Vol 05.02.

159

D 664 connected to the ground, as well as a satisfactoryterminal to connect the shielded connection wire from the glass electrode to the meter without interference from any external electrostatic field.

against the respective volumes of titrating solution and the end points are taken only at well defined inflections in the resulting curve. When no definite inflections are obtained, end points are taken at meter readings corresponding to those found for freshly prepared nonaqueous acidic and basic buffer solutions. 5. Significance and Use

5.1 New and used petroleum products may contain acidic constituents that are present as additives or as degradation products formed during service, such as oxidation products. The relative amount of these materials can be determined by titrating with bases. The acid number is a measure of this amount of acidic substance, in the oil-always under the conditions of the test. The acid number is used as a guide in the quality control of lubricating oil formulations. It is also sometimes used as a measure of lubricant degradation in service. Any condemning limits must be empirically established. 5.2 Since a variety of oxidation products contribute to the acid number and the organic acids vary widely in corrosion properties, the test method cannot be used to predict corrosiveness of an oil under service conditions. No general correlation is known between acid number and the corrosive tendency of oils toward metals. 6. Apparatus

6.1 The cell assembly used for the potentiometric titration is shown in Fig. 1.

6.2 Manual Titration Apparatus: 6.2.1 Meter, a voltmeter or a potentiometer that will operate with an accuracy of +0.005 V and a sensitivity of +0.002 V over a range of at least +0.5 V when the meter is used with the electrodes specified in 6.1.2 and 6.1.3 and when the resistance between the electrodes falls within the range from 0.2 to 20 Mfl. The meter shall be protected from stray electrostatic fields so that no permanent change in the meter readings over the entire operating range is produced by touching, with a grounded lead, any part of the exposed surface of the glass electrode, the glass electrode lead, the titration stand, or the meter. NOTE 3 - - A suitable apparatus could consist of a continuous-reading electronic voltmeter designed to operate on an input of less than 5 x 10-~2 A, when an electrode system having 1000-Mfl resistance is

connected across the meter terminals and provided with a metal shield

~j E

Floagoled Built )'Ip In fron of $ rrllr - --

Sleeve wllh Ground Gloss Conlacl Joint - ~

NOTE 4--Certain alternative electrode-electrolytecombinations have been shown to give satisfactoryresults although the precision using these alternatives has not been determined. Combination electrodes can be used for this test method provided they have sufficientlyfast response time?

'r I I I ~ I I~ --Ba.~,.c,,°o,~.. " - ' + - T l i ;I J~

6.2.4 Variable-Speed Mechanical Stirrer, a suitable type, equipped with a glass, propeller-type stirring paddle (D in Fig. 1). A propeller with blades 6 mm in radius and set at a

(I. . . . . . Ily ,Jll(ltdld)

~' ~ ~

~(

..:_

s Examples; of suitable electrodes are: (a) Glass electrodes: Beckman 41263, Coming 476022, and Metrohom E 107, (b) Referenceelectrodes:Beckman40463, Coming 476012, and Metrohom EA430, and (c) Combination electrodes: Metmhom EAI21 and EAI57.

--Propeller Sll;'rer, 0, (In back of Buret T,p}

FIG. 1

6.2.2 Glass Electrode, pencil type, 125 to 180 mm in length and 8 to 14 mm in diameter (C in Fig. 1). 6.2.2.1 The body of the electrode shall be made of a chemically resistant glass tube with a wall thickness of 1 to 3 mm. 6.2.2.2 The end dipping into the solution shall be closed with a hemisphere of glass sealed on to the electrode tube and the radius of this hemisphere shall be about 7 mm. The thickness of the glass in the hemisphere shall be great enough so that the resistance of the hemisphere is 100 to 1000 M r at 25"C. 6.2.2.3 The electrode shall contain a reproducible, permanently sealed liquid cell for making electrical connection with the inner surface of the hemisphere. 6.2.2.4 The entire electrical connection from the sealed contact cell to the meter terminal shall be surrounded by an electrical shield that will prevent electrostatic interference when the shield is grounded. 6.2.2.5 The shield shall be insulated from the electrical connection by insulating material of the highest quality, such as rubber and glass, so that the resistance between the shield and the entire length of the electrical connection is greater than 50 000 M r . 6.2.3 Calomel Reference Electrode, pencil type, 125 to 180 mm in length and 8 to 14 mm in diameter (B in Fig. 1). 6.2.3.1 This electrode shall be made of glass and shall be provided with an external, removable glass sleeve on the sealed end that is dipped into the titration solution. 6.2.3.2 The glass sleeve shall be 8 to 25 mm in length, shall be slightly tapered, and shall be ground to fit the electrode so that the sealed end of the electrode protrudes 2 to 20 mm beyond the sleeve. The ground surface shall be continuous and free of smooth spots. 6.2.3.3 At a point between the extremities of the ground surface, the electrode tube shall be pierced by a hole or holes 1 mm in diameter. The electrode shall contain the necessary mercury, calomel, and electrical connection to the mercury, all arranged in a permanent manner. 6.2.3.4 The electrode shall be filled almost to capacity with saturated KC1 electrolyte and shall be equipped with a stoppered port through which the electrolyte may be replenished. 6.2.3.5 When suspended in the air and with the sleeve in place, the electrode shall not leak electrolyte at a rate greater than one drop in l0 min.

Cell for Potentiometric Titration

160

~

D 664

pitch of 30 to 45* is satisfactory. A magnetic stirrer is also satisfactory. 6.2.4.1 If electrical stirring apparatus is used, it shall be electrically correct and grounded so that connecting or disconnecting the power to the motor will not produce a permanent change in the meter reading during the course of the titration. 6.2.5 Burette, 10-mL capacity, graduated in 0.05-mL divisions and calibrated with an accuracy of +0.02 mL (E in Fig. 1). The burette shall have a glass stopcock and shall have a tip that extends 100 to 130 mm beyond the stopcock. The burette for KOH shall have a guard tube containing soda lime or other CO2-absorbing substance. 6.2.6 Titration Beaker, 250-mL capacity, made of borosilicate glass (A in Fig. 1). 6.2.7 Titration Stand, suitable for supporting the electrodes, stirrer, and burette in the positions shown in Fig. 1. NOTE 5 - - A n arrangement that allows the removal o f the beaker without disturbing the electrodes, burette, and stirrer is desirable.

6.3 Automatic Titration Apparatus: 6.3.1 Automatic titration systems shall be generally in accordance with 6.2 and provide the following technical performance characteristics or features. 6.3.1.1 Automatic adaptation of the titration speed in the continuous titrant delivery mode to the slope of the titration curve with the capability of complying with the potential equilibrium specified and providing titration rates of less than 0.2 mL/min during titration and preferably 0.05 mL/min at inflections and at nonaqueous acid and base end points. 6.3.1.2 Interchangeable precision motor-driven burettes with a volume dispensing accuracy of _0.01 mL. 6.3.1.3 A record of the complete course of the titration by continuously printing out the relative potential versus volume of titrant added.

procured, it can be dried by distillation through a multiple plate column, discarding the first 5 % of material distilling overhead and using the 95 % remaining. Drying can also be accomplished using molecular sieves such as Linde Type 4A, by passing the solvent upward through a molecular sieve column using one part of molecular sieve per ten parts of solvent. NOTE 7: Warning--Flammable. 7.5 2,4,6 Trimethyl Pyridine (3' Collidine) ((CH3)3CsH2N) m(mol weight 121.18), (Warning--See Note 8) conforming to the following requirements: Boilingrange 168to 170"C Refractive index, n~° Color

1 498 2 :l: 0 000 5

colorless NOTE 8: Warning--2,4,6-Trimethyl Pyridine (, coUidine) is hazardous if swallowed, breathed, or spilled on skin or eyes. Precaution-Wear chemical safetygoggles, neoprene or rubber glovesand apron. Use only in a well.ventilated hood, or wear an approved respirator for organic vapor or a supplied-air respirator. Do not take internally. 7.5.1 Store the reagent over activated alumina and keep in a brown glass bottle. 7.6 m-Nitrophenol (NO2C6H4OH)m(mol weight 139.11), conforming to the following requirements (WarninguSee Note 9): Meltingpoint 96 to 97"C Color pale yellow NOTE 9: Warning--m-Nitrophenol can be hazardous if swallowed, breathed, or spilled on skin or eyes. Wear chemical-safety goggles, neoprene or rubber gloves, and apron. Use only in a well-ventilated hood, or wear an approved respirator for organic vapor or a supplied-air respirator. Do not take internally. 7.6. I Store the reagent in a brown glass bottle. 7.7 Potassium Chloride ElectrolytemPrepare a saturated solution potassium chloride (KC1) in water. 7.8 Potassium Hydroxide--(WarnlngmSee Note I0). NOTE 10: Warning--Causes severe bums.

7. R e a g e n t s

7.9 Tolueneu(Warningmsee Note 7). 7.10 HydrochloricAcid Solution, Standard Alcoholic (0.1 mol/L) (Warning--See Notes 6 and 7). Mix 9 mL of hydrochloric (HC1, relative density 1.19) acid with 1 L of anhydrous propan-2-ol. Standardize frequently enough to detect concentration changes of 0.0005 by potentiometric titration of approximately 8 mL (accurately measured) of the 0.1-mol/L alcoholic K O H solution diluted with 125 m L of CO2-free water. 7.11 HydrochloricAcid Solution, Standard Alcoholic (0.2 mol/L), (Warning--See Notes 6 and 7). Prepare and standardize as directed in 7.10 but use 18 mL of HCI (relative density 1.19). 7.12 Buffer Stock Solution A--(Warning--See Notes 7 and 8). Accurately weigh 24.2 + 0.1 g of 2,4,6-trimethyl pyridine (~-collidine), and transfer to a 1-L volumetric flask containing 100 mL of propan-2-ol. Using a l-L graduated cylinder, add to the flask, while continuously stirring its contents, 150/C + 5 mL of 0.2-mol/L alcoholic HC1 solution (C being the exact molarity concentration of the HCI solution found by standardization). Dilute to the 1000-mL mark with propan-2-ol, and mix thoroughly. Use within two weeks. 7.13 Buffer, Nonaqueous Acidic--Add l0 mL of buffer

7.1 Purity of Reagents--Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents shall conform to the specifications of the committee on Analytical Reagents of the American Chemical Society, where such specifications are available. 6 Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination. 7.2 Purity of Water--Unless otherwise indicated, references to water shall be understood to mean reagent water as defined by Type III of Specification D 1193. 7.3 Hydrochloric Acid (HCl)--Relative density 1.19 (Warning~See Note 6). NOTE 6: Warning--Corrosive, causes bums. 7.4 Propan-2-ol, Anhydrous, (less than 0.1% H20) (Warning--See Note 7). If adequately dry reagent cannot be e Reagent Chemicals, American Chemical Society Specoqcations, American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed by the American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Pc,ale, Dorset, U.K., and the United States Pharmacopeia and National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville, MD.

161

@ D 664 NOTE 12--Cleaning the electrodes7 thoroughly, keeping the groundglass joint free of foreign materials, and regular testing of the electrodes are very important in obtaining repeatable potentials, since contamination may introduce uncertain erratic and unnoticeable liquid contact potentials.6 While this is of secondary importance when end points are chosen from inflection points in the titration curve, it may be quite serious when end points are chosen at arbitrarily fixed cell potentials. NOTE 13: Warning--Causes severe burns. A recognizedcarcinogen. Strong oxidizer. Contact with materials may cause fire. Hygroscopic. 8.2 Preparation of Electrodes--Before and after using, wipe the glass electrode thoroughly with a clean cloth, or a soft absorbent tissue, and rinse with water. Wipe the calomel reference electrode with a cloth or tissue, carefully remove the ground-glass-sleeve and thoroughly wipe both ground surfaces. Replace the sleeve loosely and allow a few drops of electrolyte to drain through to flush the ground-glass joint (Note 10). Wet the ground surfaces thoroughly with electrolyre, set the sleeve firmly in place, and rinse the electrode with water. Prior to each titration, soak the prepared electrodes in water for at least 5 min immediately before use, and touch the tips of the electrodes with a dry cloth or tissue to remove the excess of water. 8.3 Testing of Electrodes--Test the meter-electrode combination when first put into use, or when new electrodes are installed, and retest at intervals thereafter by dipping the electrodes into a well-stirred mixture of 100 mL of the titration solvent and 1.0 to 1.5 mL of 0.l-mol/L alcoholic KOH solution. For the meter-electrode combination to be suitable for use, the potential between the electrodes should change by more than 480 mV from the potential between the same electrodes when dipped in the nonaqueous acidic buffer solution (Note 14). NOTE 14---Considerably more sensitive electrodes are now available that will show a potential change of at least 590 mV under these conditions, and their use is recommended. When combination electrodes are used, test as in 8.3.

stock Solution A to 100 m L of titration solvent. Use within 1 h. 7.14 Buffer Stock Solution Bin(Warning--See Notes 7 and 9). Accurately weigh 27.8 __. 0.1 g of m-nitrophenol and transfer to a I-L volumetric flask containing 100 mL of propan-2-ol. Using a 250-mL graduated cylinder, add to the flask while continuously stirring its contents, 50/C2 --- 1 mL of 0.2-mol/L alcoholic KOH solution (C2 being the exact molarity concentration of the KOH solution found by standardization). Dilute to the 1000-mL mark with propan2-ol and mix thoroughly. Use within two weeks. 7.15 Buffer Nonaqueous Basic--Add 10 mL of buffer stock Solution B to 100 mL of titration solvent. Use within 1 h. 7.16 Potassium Hydroxide Solution, Standard Alcoholic (0.1 mol/L)m(Warning--See Notes 7 and 10). Add 6 g of potassium hydroxide (KOH) to approximately l L of anhydrous propan-2-ol. Boil gently for l0 min to effect solution. Allow the solution to stand for two days and then filter the supernatant liquid through a fine sintered-glass funnel. Store the solution in a chemically resistant bottle. Dispense in a manner such that the solution is protected from atmospheric carbon dioxide (CO2) by means of a guard tube containing soda lime or soda non-fibrous silicate absorbants and such that it does not come into contact with cork, rubber, or saponifiable stopcock grease. Standardize frequently enough to detect concentration changes of 0.0005 by potentiometric titration of weighed quantities of potassium acid phthalate dissolved in CO2-free water.

7.17 Potassium Hydroxide Solution, Standard Alcoholic (0.2 tool/L), (Warning--See Notes 7 and 10). Prepare, store, and standardize as directed in 7.16, but use 12 to 13 g of KOH to approximately 1 L of propan-2-ol. 7.18 Titration Solvent--Add 500 m L of toluene (Warni n g - S e e Note 7) and 5 mL of water to 495 mL of anhydrous propan-2-ol. The titration solvent should be made up in large quantities, and its blank value determined daily by titration prior to use.

9. Standardization o f Apparatus

9.1 Determination of Meter Readings for the Nonaqueous Buffer Solutions Corresponding to Acid End Points--To ensure comparable selection of end points when definite inflection points are not obtained in the titration curve, determine daily, for each electrode pair, the meter readings obtained with freshly prepared nonaqueous acidic and basic buffer solutions. NOTE 15--The response of different glass electrodesto hydrogenion activity is not the same. Therefore, it is necessaryto establish regularly for each electrode system the meter readingscorrespondingto the buffer solutions arbitrarily selected to represent acidic or basic end points. 9.2 Prepare the electrodes as described in 8.2, immerse them in the nonaqueous buffer solution, and stir for 5 min, maintaining the temperature of the buffer solution at a temperature within 2"C of that at which the titrations are to be made. Read the cell voltage. The readings so obtained are taken as the end points in titration curves having no inflection points.

NOTE 1 l--Commercially available reagents can be used in place of laboratory preparations.

8. Preparation of Electrode S y s t e m

8.1 Maintenance of Electrodes--Clean the glass electrode (Note 12) at frequent intervals (not less than once every week during continual use) by immersing in cold chromic acid cleaning solution (Warning--See Note 13) or in other equipment cleaning solutions. Drain the calomel electrode at least once each week and refill with fresh KCI electrolyte as far as the filling hole. Ascertain that crystallized KC1 is present. Maintain the electrolyte level in the calomel electrode above that of the liquid in the titration beaker or vessel at all times. When not in use, immerse the lower halves of the electrodes in water. Do not allow them to remain immersed in titration solvent for any appreciable period of time between titrations. While the electrodes are not extremely fragile, handle them carefully at all times.

For a detaileddiscussionof the needfor care in preparation of the electrodes, see Lykken, L., Porter, P., Ruliffson, H. D., and Tuemmler, F. D., "Potentiometric Determination of Acidity in HighlyColoredOils," Industrialand Engineering

Chemistry,AnalyticalEdition,IENAA,Vol 16, 1944,pp. 219-234.

162

i{~ D 664 30 mV in the cell potential, add 0.05-mL portions. 11.3.3 In the intermediate regions (plateaux) where 0.1 mL of 0.1-mol/L alcoholic KOH changes the cell potential less than 30 mV, add larger portions sufficient to produce a total potential change approximately equal to, but not greater than 30 inV. l 1.3,4 Titrate in this manner until the potential changes less than 5 mV/0.1 mL of KOH and the cell potential indicates that the solution is more basic than the freshly prepared nonaqueous basic buffer. 11.3.5 Remove the titration solution, rinse the electrodes and burette tip with the titration solvent, then with propan2-ol and finally with reagent grade water. Immerse the electrodes in water for at least 5 min before using for another titration to restore the aqueous gel layer of the glass electrode. Store the electrodes in reagent water when not in use. If the electrodes are found to be dirty and contaminated, proceed as in 8. I. I 1.4 Automatic Titration Method." I 1.4.1 Adjust the apparatus in accordance with the manufacturer's instructions to comply with the potential equilibrium mode requirements established for the manual titration as explained in l l.3.1 or to provide a variable continuous delivery rate mode of titration of less than 0.2 mL/min during the titration and preferably 0.05 mL/min through the region of inflections and at the end point corresponding to that found for the freshly prepared standard nonaqueous basic buffer solution. 11.4.2 Proceed with the automatic titration and record potentiometric curves or derivative curves as the case may be. 11.4.3 Titrate in this manner with the 0.1-mol/L alcoholic KOH solution until the potential becomes constant, for example, changing less than 5 mV/0.1 mL (automatic end point) or until the potential reading indicates that the solution is more basic than the freshly prepared nonaqueous basic buffer solution (preselected end point). 11.4.4 On completion of the titration, rinse the electrodes and burette tip with the titration solvent, then with propan2-ol, and finally with reagent grade water. Keep the electrodes immersed in water for at least 5 min before reusing for another titration to restore the aqueous gel layer of the glass electrode. If electrodes are found dirty and contaminated proceed as in 8.1. Store the electrodes in reagent grade water when not in use. 11.5 Blanks: 11.5.1 For each set of samples, make a blank titration of 125 mL of the titration solvent. For manual titration, add 0. l-mol/L alcoholic KOH solution in 0.05-mL increments, waiting between each addition until a constant cell potential is reached. Record the meter and burette readings when the former becomes constant after each increment. For automarie titration proceed as in 11.4. 11.5.2 For each set of samples, make a blank titration of 125 mL of titration solvent, adding 0. I mol/L alcoholic HCI solution in 0.05-mL increments in a manner comparable to that specified in 11.5.1.

10. Preparation of Sample of Used Oil 10.1 Strict observance of the sampling procedure is necessary since the sediment itself is acidic or basic or has absorbed acidic or basic material from the sample. Failure to obtain a representative sample causes serious errors. NOTE 16--As used oil can change appreciably in storage, test samples as soon as possible after removal from the lubricating system; and note the dates of sampling and testing.

10.2 Heat the sample (Note 17) of used oil to 60 + 5"C in the original container and agitate until all of the sediment is homogeneously suspended in the oil. If the original container is a can or if it is glass and more than three-fourths full, transfer the entire sample to a clear-glass bottle having a capacity at least one third greater than the volume of the sample. Transfer all traces of sediment from the original container to the bottle by violent agitation of portions of the sample in the original container. NOTE 17--When samples are visibly free of sediment, the heating procedures described can be omitted.

10.3 After complete suspension of all sediment, strain the sample or a convenient aliquot through a 100-mesh screen for the removal of large contaminating particles.

11. Procedure for Acid Number and Strong Acid Number 11.1 Into a 250-mL beaker or a suitable titration vessel, introduce a weighed quantity of sample as prescribed in Table 1 and add 125 mL of titration solvent (Note 18). Prepare the electrodes as directed in 8.2. Place the beaker or titration vessel on the titration stand and adjust its position so that the electrodes are about half immersed. Start the stirrer, and stir throughout the determination at a rate sufficient to produce vigorous agitation without spattering and without stirring air into the solution. If feasible, adjust the meter so that it reads in the upper part of the millivolt scale, for example 700 mY. NOTE 18--A titration solvent that contains chloroform (Warning-May be fatal if swallowed. Harmful if inhaled. May produce toxic vapors if burned) can be used in place of toluene to completely dissolve certain heavy residues of asphaltic materials.

11.2 Select the right burette, flU with the 0.1-mol/mL alcoholic KOH solution, and place the burette in position on the titration assembly, ensuring that the tip is immersed about 25 mm in the liquid in titration vessel. Record the initial burette and meter (cell potential) readings. 11.3 Manual Titration Method: 11.3.1 Add suitable small portions of 0. l-mol/L alcoholic KOH solution and wait until a constant potential has been established, record the burette and meter readings. 11.3.2 At the start of the titration and in any subsequent regions (inflections) where 0.1 mL of the 0. l-mol/L KOH solution consistently produces a total change of more than TABLE 1 Acid Number 0.05-1.0 1.0-5.0 5-20 20-100 100-260

Size of Test Portion

Mass of Test Portion, g 20.0 5.0 1.0 0.25 0.1

+ + + + +

2.0 0.5 0.1 0.02 0.01

Accuracy of Weighing, g 0.10 0.02 0.005 0.001 0.0005

12. Calculation 12.1 Manual Titration--Plot the volumes of the 0.1mol/L alcoholic KOH solution added against the corre163

~

D 664 TABLE 2

sponding meter readings (see Fig. 2). Mark as an end point, only well-defined inflection point (Note 19) that is closest to the cell voltage corresponding to that obtained with the freshly prepared nonaqueous acidic and basic buffers. If inflections are ill-defined or no inflection appears (see Fig. 2, Curve B), mark the end point at the meter reading corresponding to that obtained with the appropriate freshly prepared nonaqueous buffer.

Titration Mode

TABLE 3

/

0 200

/

9 OIOO

8 o

g

% 7~

0 000

6~ _~ -O,IOO uJ

s Jr, 0

3/ml

4

'.77ml

3 z J 0

I i

I 2

I 3

I 4

J 5

I 6

Fresh Oils and Additive Concentrates at Inflection Points

Used Oils at Buffer End Points

Manual

Automatic

Manual

Automatic

20

28

39

44

(1) (2)

13.2 No modifications to this test method are permitted.

I 7

Millihtres of 0. I/M Alcoholic KOH Solution

14. Precision and Bias

NOTE--Key: Curve A--Blank on 125 mL of titration solvent. Curve B--10.00 g of used crankcase oil plus 125 mL of titration solvent. Since no sharp inflections are apparent, the end points are chosen at the meter readings obtained with the two nonaqueous buffer solutions. Curve C l l 0 . 0 0 g of oil containing a weak acid plus 125 mL of titration solvent. The end point is chosen as the point at which the curve is most nearly vertical. Curve D--10.00 g of oil containing weak and strong acids plus 125 mL of titration solvent. The end points are chosen as the points at which the curve is most nearly vertical. FIG. 2

12

13. Report 13.1 Report the results as acid number or strong acid number as follows: Acid number (Test Method D 664) - (result) Strong acid number (Test Method D 664) = (result)

-O.200

-0,300

Automahc

5

where: A = alcoholic KOH solution used to titrate sample to end point that occurs at the meter reading of the inflection point closest to the meter reading corresponding to basic nonaqueous buffer, or in case of ill-defined or no inflection point, to the meter reading corresponding to the basic nonaqueous buffer, mL, B = volume corresponding to A for blank titration, mL, M = concentration of alcoholic KOH solution, mol/L, m = concentration of alcoholic HCI solution, tool/L, W = sample, mass, g, C = alcoholic K O H solution used to titrate the sample to end point that occurs at a meter reading corresponding to acid nonaqueous buffer, mL, and D = alcoholic HCI solution used to titrate solvent blank to end point corresponding to C, mL.

io

_?

Manual

6

Acid number, mg KOH/g = (A - B) x M x 56.1/ W Strong acid number, mg KOH/g - (CM + Dm) x 56.1/W

H

°

Automatic

7

12.2 Automatic Titration Method--Mark the end points on the curves obtained in 11.4, in the same way as for the manual titration method. 12.3 Method of Calculation--The method in 12.3.l is applicable to both manual and automatic methods. 12.3.1 Calculate the acid number and strong acid number as follows:

t2

.f

End Points

Manual

Percentage of mean

NOTE 20--The cooperative work done on acid number determinations on fresh oils, additive concentrates, and used oils indicated well-defined inflection points for fresh oils and additive concentrates, and generally ill-defined inflections, or no inflection points at all, for used oils.

)

Used Otis a~ BuYer

Reproducibility of Acid Number Determination

Titration Mode

12.1.1 For all acid titrations on used oils, mark as an end point, the point on the curve that corresponds to the freshly prepared nonaqueous basic buffer end point (Note 20).

-,oy

Fresh Oils and Additive Concentrates at Inflection Points

Percentage of mean

NOTE 19--One inflection point is generally recognizable by inspection whenever several successive 0.05-mL increments each produce a cell potential change greater than 15 mV at least 30 % greater than those produced by previous or subsequent increments of the same size. Generally, definite inflection points may be discerned only in regions where increments of the same size are used.

0 300

Repeatability of Acid Number Determination

14.1 AcM Number." 14.l. l Repeatability--The difference between successive test results obtained by the same operator with the same apparatus under constant operating conditions on identical test material would in the long run, in the normal and correct operation of the test method, exceed the following values only in one case in twenty: 14.1.2 Reproducibilit)u--The difference between two single and independent results obtained by different operators working in different laboratories on identical test mate-

Illustrative Titration Curves

164

q~ D 664 rial would, in the long run, in the normal and correct operation of the test method, exceed the following values only in one case in twenty: 14.2 Strong Acid Number." 14.2. l Precision data have not been developed for strong acid number because of its rare occurrence in sample analysis.

14.3 Bias--The procedures in this test method have no bias because the acid values can be defined only in terms of the test method. 15. Keywords

15.1 acid number; lubricants; petroleum potentiometric; strong acid number; titration

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and ff not revised, either reepproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend, ff you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 100 Barr Harbor Drive, West Conshohockan, PA 19428.

165

products;

~l~

Designation~ D 721 ~ 87 (Reapproved 1 9 9 3 ) ~1

An American National Standard Technical Association of Pulp end

Paper Industry Tentative Method T 636

TIIFn-rmNJ-uM INSTITLn'EDesignation: 158/69(85) ol-

Standard Test Method for Oil Content of Petroleum Waxes 1 This standard is issued under the fixed designation D 721; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (¢) indicates an editorial change since the last revision or reapproval. This is also a standard of the Institute of Petroleum issued under the fixed designation IP 158. The final number indicates the year of last revision.

This test method was prepared jointly by the Technical Association of Pulp and Paper Industry and the American Society for Testing and Materials. This test method was issued as a joint ASTM-IP tentative in 1964. This test method has been adopted for use by government agencies to replace Method 5431 of Federal Test Method Standard No. 791b. El NoTE--Keywords were added editorially in October 1993.

D 1364 Test Method for Water in Volatile Solvents (Fischer Reagent Titration Method) 3 D 1613 Test Method for Acidity in Volatile Solvents and Chemical Intermediates Used in Paint, Varnish, Lacquer, and Related Products 3 E 1 Specification for ASTM Thermometers 5 E 128 Test Method for Maximum Pore Diameter and Permeability of Rigid Porous Filters for Laboratory Use 6

1. Scope 1.1 This test method covers the determination of oil in petroleum waxes having a congealing point of 30°C (86°1:) or higher as determined in accordance with Test Method D 938, and containing not more than 15 % of oil. 2 1.2 The values stated in inch-pound units are to be regarded as the standard. The values in parentheses are for information only. NOTE l--With some types of waxes, ofoil contents greater than 5 %, there may be an incompatibilitywith MEK resulting in the formation of two liquid phases. If this occurs, the method is not applicable to the material under test.

3. Summary of Test Method 3.1 The sample is dissolved in methyl ethyl ketone, the solution cooled to -32"C (-25"1:) to precipitate the wax, and filtered. The oil content of the filtrate is determined by evaporating the methyl ethyl ketone and weighing the residue.

1.3 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

4. Significance and Use 4.1 The oil content of a wax may have significant effects on several of its properties, such as strength, hardness, flexibility, scuff resistance, coefficient of friction, coefficient of expansion, melting point and oil straining. The importance of these effects may be dependent upon the ultimate use of the wax.

. Referenced Documents

2.1 A S T M Standards: D 740 Specification for Methyl Ethyl Ketone 3 D938 Test Method for Congealing Point of Petroleum Waxes, Including Petrolatum 4 D 1018 Test Method for Hydrogen in Petroleum Fractions 4 D 1218 Test Method for Refractive Index and Refractive Dispersion of Hydrocarbon Liquids 4

5. Apparatus 5.1 Filter Stick and Assembly, consisting of a 10-mm diameter sintered glass filter stick of 10 to 15/am maximum pore diameter as determined by the method in Appendix X 1, provided with an air pressure inlet tube and delivery nozzle. It is provided with a ground-glass joint to fit a 25 by 170-mm test tube. The dimensions for a suitable filtration assembly are shown in Fig. 1.

nThis test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.10 on Properties of Petroleum Wax. in the lP, this method is under the jurisdiction of the Standardization Committee. Current edition approved Oct. 30, 1987. Published December 1987. Originally published as D 721 - 43 T. Last previous edition D 721 - 68 (1982). 2 This test method is being used by some laboratories for products of higher oil content. 3 Anmzal Book of ASTM Standards, Vol 06.04. 4 Annual Book of ASTM Standards, Vol 05.01.

NOTE 2--A metallic filter stick may be employed if desired. A filter stick made of stainless steel and having a 12.7-mm (I/=-in.)disk of l0 to s Annual Book of ASTM Standards, Vols 05.03 and 14.03. 6 Annual Book of ASTM Standards, Vol 14.02.

166

~ 65-75

35-4,=

1

P, I-5-2'5 I

"

nected to the filter stick and assembly by means of rubber tubing. 5.6 Thermometer, having a range as shown below and conforming to the requirements as prescribed in Specification E 1, or in the Specifications for IP Standard Thermometers.

19-21 ID

T N

m~

D 721

Thermometer Number

1

824-

(OREOUtVALENT)"

lllII': //

IN DIRECTION OF ARROW 'X'

25 OD COOLING TUBE f

SINTERED GLASS DISK

1" All dimensions are in millirnetres FIG. 1

ASTM

IP

-37 to +21"C - 3 5 to +70"F

... 7IF

72C 72F

5.7 Weighing Bottles, conical in shape and glass-stoppered, having a capacity of 15 mL. 5.8 Evaporation Assembly, consisting of an evaporating cabinet and connections, essentially as illustrated in Fig. 4, and capable of maintaining a temperature of 35 + I*C (95 _ 2*F) around the evaporation flasks. Construct the jets with an inside diameter of 4 4- 0.2 mm for delivering a stream of clean, dry air vertically downward into the weighing bottle. Support each jet so that the tip is 15 4- 5 mm above the surface of the liquid at the start of the evaporation. Supply air at the rate of 2 to 3 L/min per jet, purified by passage through a tube of 10-ram bore packed loosely to a height of 200 mm with absorbent cotton. Periodically check the cleanliness of the air by evaporating 4 mL of methyl ethyl ketone by the procedure specified in 7.5. When the residue does not exceed 0.1 rag, the evaporation equipment is operating satisfactorily. 5.9 AnalyticalBalance, capable of reproducing weights to 0.1 rag. The sensitivity should be adjusted so that 0.1 mg will deflect the pointer one half division on the pointer scale. 5.10 WireStirrer--A piece of stiff iron or Nichrome wire of about No. 20 B & S-(0.9 mm in diameter) or 20 swg gage, 250 mm long. A 10-ram diameter loop is formed at each end, and the loop at the bottom end is bent so that the plane of the loop is perpendicular to the wire.

GLASS HOOKS - 2"-5--35-!~

Temperature Range

Filter Stick

15 lam maximum pore diameter, as determined by Method E 128, has been found to be satisfactory. 7 The metallic apparatus is inserted into a 25 by 150-ram test tube and held in place by means of a cork.

5.2 CoolingBath, consisting of an insulated box with 25.4 mm (l-in.) holes in the center to accommodate any desired number of test tubes. The bath may be filled with a suitable medium such as kerosine, and may be cooled by circulating a refrigerant through coils, or by using solid carbon dioxide. A suitable cooling bath to accommodate three test tubes is shown in Fig. 2. 5.3 Dropper Pipet, provided with a rubber bulb, and calibrated to deliver 1 + 0.05 g of molten wax. 5.4 TransferPipet, calibrated to deliver 15 4- 0.06 mL. 5.5 Air Pressure Regulator, designed to supply air to the filtration assembly (8.5) at the volume and pressure required to give an even flow of filtrate. Either the conventional pressure-reducing valve or a mercury bubbler-type regulator has been found satisfactory. The latter type, illustrated in Fig. 3, consists of a 250-mL glass cylinder and a T-tube held in the cylinder by means of a rubber stopper grooved at the sides to permit the escape of excess air. The volume and pressure of the air supplied to the filtration assembly is regulated by the depth to which the T-tube is immersed in mercury at the bottom of the cylinder. Absorbent cotton placed in the space above the mercury prevents the loss of mercury by spattering. The air pressure regulator is con-

6. Reagents

6.1 Methyl Ethyl Ketone, conforming to Specifications D 740, having a refractive index 20"C (68"F) of 1.378 40.002 as determined in accordance with Test Method D 1218 or conforming to the following specifications: Property Specific gravity 20/20'C Color

Value 0.805 to 0.807 Water white, 1.0

Method IP 17(B)

max

Distillation range: Below 78"C Above 81"C Acidity Water content Residue on evaporation

Refractive index at 20"C

ni ni 0.003 weight % max (expressed as acetic acid) no more than 0.3 % by weight residue remaining after evaporation of 4 mL by procedure in 8.5 shall not exceed 0.1 ms. 1.378 + 0.002

) I ASTM D 1078 ASTM D 1613 ASTM D 1364

(68"F) 6.2 Store the solvent over anhydrous calcium sulfate (5 weight % of the solvent). Filter prior to use.

7 A suitable metal filter stick with designated porosity G may be obtained from the Pall Trinity Micro Corp., Route 281, Coffland, N. Y., 13045. A list of United Kingdom suppliers can be obtained from the Institute of Petroleum, 61 New Cavendish St., London, W. I, England.

7. Sample 7.1 If the sample of wax is I kg (2 lb) or less, obtain a 167

~)

D 721

THERMOMETER

AIR PRESSURE FILTER STICK

PHENOLIC PLASTIC PANEL

GLASS WOOL INSULATION

CASE

r'UBE

I LITRE (1QuNTr) CAPACITY FILLED WITH COOLING MEOI UM

a

-;

{~O) All dimensions are in mJllimetres (inches).

FIG. 2 CoolingBath representative portion by melting the entire sample and stirring thoroughly. For samples over 1 kg (2 lb), exercise special care to ensure obtaining a truly representative portion, bearing in mind that the oil may not be distributed uniformly throughout the sample, and that mechanical operations may express some of the oil.

and weigh to the nearest 1 mg. NOTE 3--The weight of a test tube which is cleaned by means of solvents will not vary to a significantextent. Therefore, a tare weight may be obtained and used repeatedly. 8.2 Pipet 15 mL of methyl ethyl ketone into the test tube and place the latter just up to the level of its contents in a hot water or steam bath. Heat the solvent wgx mixture, stirring up and down with the wire stirrer, until a homogeneous solution is obtained. Exercise care to avoid loss of solvent by prolonged boiling. NffrE 4--Very high-meltingwax samples may not form clear solutions. Stir until the undissolvedmaterial is welldispersedas a fine cloud. 8.2.1 Plunge the test tube into an 800-mL beaker of ice water and continue to stir until the contents are cold. Remove the stirrer. Remove the test tube from the ice bath, wipe dry on the outside with a cloth, and weigh to the nearest 0.1g. NOTE 5--During this operation the loss of solvent through vaporization should be less than 1%. The weight of the solvent is, therefore,

8. Procedure 8.1 Melt a representative portion of the sample in a beaker, using a water bath or oven maintained at 70 to IO0°C (160 to 210°F). As soon as the wax is-completely melted, thoroughly mix by stirring. Preheat the dropper pipet in order to prevent the solidification of wax in the tip, and withdraw a l-g portion of the sample as soon as possible after the wax has melted. Hold the pipet in a vertical position, and carefully transfer its contents into a clean, dry test tube previously weighed to the nearest 1 mg (Note 3). Swirl the test tube so as to coat the bottom evenly with wax. This permits more rapid solution later. Allow the test tube to cool, 168

~

D 721 Unstopper the weighing bottle and place it under one of the jets in the evaporation assembly maintained at 35 ± I'C (95 _ 2*F), with the air jet centered inside the neck, and the tip 15 ± 5 mm above the surface of the liquid. After the solvent has evaporated, which usually takes less than 30 min, remove the bottle, stopper, and place near the balance. Allow to stand for 10 rain and weigh to the nearest 0.1 mg. Repeat the evaporation procedure, using a 5-min evaporation period instead of 30 min, until the loss between successive weighings is not over 0.2 mg.

¢OTI'I~----~ MIERCURY~

--~

TUBINO

9. Calculation 9.1 Calculate the amount of oil in the wax as follows: Oil in wax, weight % ffi (100 AC/BD) - 0.15 where: A = weight of oil residue, g, B = weight of wax sample, g, C = weight of solvent, g, obtained by subtracting weight of test tube plus wax sample (8.1) from weight of test tube and contents (8.2), and D = weight of solvent evaporated, g, obtained by subtracting weight of weighing bottle plus oil residue from weight of weighing bottle plus filtrate (7.5). 0.15 = average factor correcting for the solubility of wax in the solvent at -32"C (-25"F).

All dimensionsare in millimetres. FIG. 3 Air Pressure Regulator practicallya constant, and, after a few samplesare weighed,this weight, approximately 11.9 g, can be used as a constant factor. 8.3 Insert the thermometer into the test tube and place the test tube containing the wax-solvent slurry in the cooling bath, which is maintained at -34.5 ± I°C (-30 ± 2*F). During this chilling operation it is important that stirring by means ofthe thermometer be almost continuous, in order to maintain a slurry of uniform consistency as the wax precipitates. Do not allow the wax to set up on the walls of the cooling vessel nor permit any lumps of wax crystals to form. Continue stirring until the temperature reaches -31.7 ± 0.3"C (-25 _ 0.5°F). 8.4 Remove the thermometer from the tube and allow it to drain momentarily into the tube; then immediately immerse in the mixture the clean dry filter stick which has previously been cooled by placing it in a test tube and holding at -34.5 ± I°C (-30 ± 2*F) in the cooling bath for a minimum of 10 min. Seat the ground-glass joint of the filter so as to make an air-tight seal. Place an unstoppered weighing bottle, previously weighed together with the glass stopper to the nearest 0.1 mg, under the delivery nozzle of the filtration assembly.

10. Report 10.1 Report the result as oil content, D 721. If the result is negative, report as zero.

NOTE 6--Take every precaution to ensure the accuracyof the weight of the stoppered weighingbottle. Prior to determiningthis weight, rinse the clean, dry, weighing bottle and stopper with methyl-ethylketone, wipe dry on the outside with a cloth, and place in the evaporation assembly to dry for about 5 rain. Then remove the weighingbottle and stopper, place near the balance, and allow to stand for 10 min prior to weighing. Stopper the bottle during this cooling period. Once the weighing bottle and stopper have been dried in the evaporation assembly, lift only with forceps. Take care to remove and replace the glass stopper with a light touch. 8.5 Apply air pressure to the filtration assembly, and immediately collect about 4 mL of filtrate in the weighing bottle. Release the air pressure to permit the liquid to drain back slowly from the delivery nozzle. Remove the weighing bottle immediately, and stopper and weigh to the nearest 10 mg without waiting for it to come to room temperature.

11. Precision and Bias 11.1 Precision--The precision of this test method as determined by statistical examination of interlaboratory results is as follows: 11.1.1 Repeatability--The difference between two test results, obtained by the same operator with the same apparatus under constant operating conditions on identical test material, would in the long run, in the normal and correct operation of the test method, exceed the following values only in one case in twenty: 0.06 + 8 % of the mean 11.1.2 Reproducibility--The difference between two single and independent results obtained by different operators working in different laboratories on identical test material would, in the long run, in the normal and correct operation of the test method, exceed the following values only in one case in twenty: 0.2 + 11% of the mean 11.2 Bias--The procedure in this test method has no bias because the value of oil content can be defined only in terms of a test method. 12. Keywords 12.1 oil content; petroleum wax; wax

169

~1~ D 721

HALFSECTIONA-A ~ E A T E R

,~,~'--.:~-~ ~ ~

I~RFORATEDMETAL PLATFORM6'5 (1,~4) DIAHOLES

CONTROL

~" POCKET

HALF 5£CTION'B-ff All dimensions

ate in millimettes (inches).

FIG. 4 EvaporationAssembly

APPENDIX (Nonmandatory Information) X1. M E T H O D O F T E S T FOR M E A S U R E M E N T O F M A X I M U M P O R E D I A M E T E R OF R I G I D POROUS FILTERS X1.2 Definition X I.2.1 maximum pore diameternthe diameter in micrometers of the largest opening in the filter.

X I . I Scope X I . I . I This method covers the determination of the acceptability of porous filter sticks used for filtration in D 721. This method establishes the m a x i m u m pore diameter and also provides a means of detecting and measuring changes which occur from continued use.

NOTE X l.l--It is recognized that the maximum pore diameter as defined herein does not necessarily indicate the physical dimensions of the largest pore in the filter. It is further recognized that the pores are 170

~) Source of Air

D 721

XI.4.4 Drying Oven. 3 ~ A i r Filter

Xl.5 Procedure X I.5.1 Clean the filter sticks by soaking in concentrated hydrochloric acid, and then wash them with distilled water. Rinse with acetone, air dry, and place in drying oven at 220°F (105°C) for 30 min. XI.5.2 Thoroughly wet the clean filter to be tested by soaking it in distilled water. XI.5.3 Assemble the apparatus as shown in Fig. X l . l . Apply pressure slowly from a source of clean air. XI.5.4 Immerse the filter just below the surface of the water. NOTE X 1.2--If a head of liquid exists above the surface of the filter,

:<--- Regulating Valve :~

.•.Filter Stick

Drying Bulb

Manometer

Beaker of Water

FIG. X1.1 Assembly of Apparatus for Checking Pore Diameter or Filter Sticks

the back pressure produced must be deducted from the observed

highly irregular in shape. Because of the irregularityin shape and other phenomena characteristicof filtration, a filter may be expected to retain all particles larger than the maximum pore diameter as defined and determined herein, and will generally retain particles which are much smaller than the determined diameter.

pressure. XI.5.5 Increase the air pressure to I0 mm below the acceptable pressure limit and then at a slow uniform rate of about 3 m m Hg/min until the first bubble passes through the filter. This can be conveniently observed by placing the beaker or test tube over a mirror. Read the manometer when the first bubble passes off the underside of the filter.

Xl.3 Summary of Method X I.3.1 The filter is cleaned and wetted with water. It is then immersed in water and air pressure is applied against its upper surface until the first bubble of air passes through the filter. The maximum pore diameter is calculated from the surface tension of water and the applied pressure.

X1.6 Calculation X I.6. I Calculate the pore diameter as follows: D = 2180/p

X1.4 Apparatus X I.4.1 Manometer, mercury filled and readable to 0.5 mm. X 1.4.2 Air Supply, clean and filtered. XI.4.3 Air Pressure Regulator, needle-valve type.

where: D = pore diameter, ~ m , and p = manometer reading, m m Hg. NOTE XI.3--From this equation, pressure corresponding to the upper and lower limitsof the specifiedpore diameterscan be calculated. These pressuresmay be used for acceptance testing.

The American Society for Testing and Materials takes no position respecting the validity of any patent rights esserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and ff not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should-be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend, ff you fee/that your comments have not received e fair hearing yod should make your views known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103.

171

~IT~ Designation: D 848 - 97 Standard Test Method for Acid Wash Color of Industrial Aromatic Hydrocarbons 1 This standard is issued under the luted designation D 848; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (0 indicates an editorial change since the last revision or reapproval.

This test method has been approvedfor use by agencies of the Department of Defense. Consult the DoD Index of Specifications and Standards for the specific year of issue which has been adopted by the Department of Defense.

1. Scope 1.1 This test method covers the determination of the acid wash color of benzene, toluene, xylenes, refined solvent naphthas, and similar industrial aromatic hydrocarbons. 1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements, see Section 8 and Note I.

material to be discolored.

2. Referenced Documents

2.1 A S T M Standards: D 1193 Specification for Reagent Water2 D 3437 Practice for Sampling and Handling Liquid Cyclic Products3 D 4790 Terminology of Aromatic Hydrocarbons and Related Chemicals3 2.2 Other Document: OSHA Regulations. 29 CFR, paragraphs 1910.1000 and 1910.12004 3. Terminology 3.1 See Terminology D 4790 for definitions of terms used in this test method. 4. Summary of Test Method 4.1 A mixture of the aromatic hydrocarbon and sulfuric acid is vigorously shaken and the color of the acid layer is compared with that of color standards prepared from CoCI2 and FeCl 3. 5. Significance and Use 5.1 This test method is suitable for setting specifications on the materials referenced in 1.1. It may also be used as an internal quality control tool and in development or research work. 5.2 The color developed in the acid layer gives an indication of impurities which if sulfonated would cause the

6. Apparatus 6.1 Containers for Color StandardsmClear and unblemished, clean, French square, flint-glass, fiat-bottom, glassstoppered, 1-oz capacity bottles holding 31 to 33 mL when filled to the neck. The bottles shall be numbered consecutively from 0 to 14. 6.2 Test ContainersmContaJners exactly like those described in 6.1 except that each French square bottle shall be marked by etching to show when the bottle contains the volume of 7 and 28 mL, respectively. Colored crayons and similar markers shall not be used for marking the bottles. 7. Reagents 7.1 Purity of Reagents--Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, where such specifications are available. 5 Other grades may be used provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination. 7.2 Purity of Water--Unless otherwise indicated, references to water shall be understood to mean distilled water, Type I or II as described in Specification D 1193. 7.3 Cobalt Chloride (COC12.6H20). 7.4 Ferric Chloride (FeCl3.6H20). 7.5 Hydrochloric Acid (l+39)--Mix 25 mL of hydrochloric acid (31 weight % HCI) with 975 mL of water. 7.6 Potassium Chromate (K2CrO4). 7.7 Potassium Dichromate (K2Cr207). 7.8 Sulfuric Acid (96 + 0.5 weight % H 2 8 0 4 ) . 7.9 Sulfuric Acid (78 + 0.5 weight % H2SO4). 8. Hazards 8.1 Consult current OSHA regulations, supplier's Material Safety Data Sheets, and local regulations for all materials used in this test method. 8.2 When handling strong acids or acid cleaning solutions, wear proper personnel protective equipment.

l This test method is under the jurisdiction of ASTM Committee D-16 on Aromatic Hydrocarbons and Related Chemicals and is the direct responsibility of Subcommittee DI6.0A on Benzene, Toluene, Xylenes, Cyclohexane, and Their Derivatives. Current edition approved June 10, 1997. Published September 1997. Originally published as D 848 - 45. Last previous edition D 848 - 93. 2 Annual Book of ASTM Standards, Vol I 1.01. 3 Annual Book of ASTM Standards, Vol 06.04. 4 Available from Superintendent of Documents, U.S. Government Printing Office, Washington, DC 20402.

5 Reagent Chemicals, American Chemical Society Specifications, American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed by the American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.

172

~

D 848

9. Sampling 9.1 Sample the material in accordance with Practice D 3437.

TABLE 1

Acid Strengths and Standing Times Sample

Group 1

10. Cleaning of Containers 10.1 Clean the containers (Section 6) with a cleaning solution that will not impact the results, such as a chromatic acid substitute, rinse with tap water followed by distilled water, and dry in an oven set at a minimum of I05"C for at least 1 h. Likewise, clean all other glassware used in this test method. 11. Preparation of Reference Color Standards 1 I, 1 Stock Solutions--Prepare the following basic reagent solutions for use in preparing the reference color standards: 11.1.1 Solution A--Dissolve 59.50 g of CoC12. 6H20 in HCI (1+39) and make up to 1 L in a volumetric flask with HCI (1 +39). 11.1.2 Solution B---Dissolve 45.054 g of FeCI 3 • 6H20 in HCI (1+39) and make up to 1 L in a volumetric flask with HCI (1+39). 11.1.3 Solution C - - M i x 31/2 volumes of Solution A with 36V2 volumes of Solution B and dilute with 90 volumes of water. 11.1.4 Solution D - - M i x 31/2 volumes of Solution A with 361/2 volumes of Solution B. 11.1.5 Solution E--Prepare an aqueous solution of K2CrO4 saturated at 2 I*C. 11.1.6 Solution F--Prepare an aqueous solution of K2Cr207 saturated at 2 I*C and dilute with an equal volume of water. 11.2 Prepare reference color standard solutions having the following compositions and numbered from 0 to 14:

Benzene, all ASTM grades Toluene, all ASTM grades Xylene, nitration grads Xylens, 5* Xylens, 10" Any other more highly refined products

Add Strength.

Standing Time, min

96

15

Group 2

Xylene, industrial grade Refined solvent naphtha

96

5

Group 3

Hi-flash solvent Heavy solvent naphtha

78

5

tested (Note 1). Drain the rinsings and fill with the acid up to the 7-mL mark. Add sufficient sample to bring the total volume to the 28-mL mark (Note 2). Insert the stopper, hold a finger over the stopper, and give vigorous shakes with a stroke of 13 to 25 cm (5 to 10 in.), shaking for a total of 150 cycles over a period of 40 to 50 s, that is at a rate of 3 to 3.75 cycles/s. NOTE l--Precaution: Concentrated sulfuric acid will cause severe burns on contact with the skin. As a precaution the test container should be wrapped in a towel or enclosed in a plastic bag during the shaking period. NOTE 2--If the room temperature is above 85"F, maintain the acid, ~mple, and reference color standards at a temperature between 77 and 85"F (25 and 29"C) through the test, and insulate the test container in some convenient way, such as wrapping with a cloth, during the shaking period. 12.2 Allow the container to stand, protected from direct sunlight, for the period of time shown in Table 1. Without further delay, invert the container gently once or twice to obtain a uniform color in the acid layer, and compare the color of the acid layer with that of the standards (10.3). Make the comparison against a white background or against daylight, using transmitted light (Note 3). When testing samples in Group I (Table 1), observe the color of the oil layer as well as that of the acid layer.

NO. 0--Distilled water. No. 1--1 volume of Solution C plus 1 volume of water. No. 2--5th volumes of Solution C plus 2 volumes of water. No. 3---solution C. No. 4---1 volume of Solution D plus 1 volume of water. No. 5--5th volumes of Solution D plus 2 volumes of water. No. 6---solution D. No. 7--5 volumes of Solution E plus 2 volumes of water. No. 8--Solution E. No. 9--7 volumes of Solution E plus I/2 volume of Solution F. No. 10--61/2 volumes of Solution E plus 1 volume of Solution F. No. 11--51/2 volumes of Solution E plus 2 volumes of Solution F. No. 12--1 volume of Solution E plus 1 volume of Solution F. No. 13--2 volumes of Solution E plus 5 volumes of Solution F. No. 14--Solution F.

NOTE 3--Agreement of results may be improved by using a color comparator of a suitable type for observingthe color of the acid layer in comparison with the reference standard color solution. 12.3 Designate the color of the acid layer by the number of the nearest matching standard, following the number with a plus or minus sign if the sample is darker or lighter, respectively, than the standard. Disregard any difference in hue and determine only whether the color o f the acid layer is darker or lighter than the color of the reference standard to which the sample most nearly corresponds. If the hue of the acid color is different from the hue of the reference color standard, record the color number followed by (X). Thus "No. 4 - (X)" means that the acid wash test color is slz'ghtly lighter than No. 4 color standard and that the hue of the No. 4 color standard is not the same as the hue of the acid layer.

1 1.3 Rinse the No. 0 container (5.1) and its glass stopper three times with water, t'dl with water, and stopper. Rinse the No. 1 container and its stopper three times with reference color standard solution No. 1 (Section 11.2), fill with this solution, and stopper. In this way, prepare the set of containers of color standards from 0 through 14 having the compositions shown for the corresponding color solution standards in 11.2. When Idling the French square bottles, leave 1/4 in. (6 mm) of vapor space below the neck of the bottle. Seal each container with paraffin to prevent loss by evaporation or seepage.

13. Interpretation of Results 13.1 Report Group 1 samples (Table 1) as passing the test only when the oil layer shows no change in color and when the acid layer is not darker than the specified color standard.

12. Procedure 12.1 Rinse a test container (5.2) twice with acid of the strength specified in Table 1 for the type of sample to be 173

~

D 848 sion estimates taken from these data are as follows:

A cloudiness or haze in the oil layer should not be interpreted as a change in color. 13.2 When testing samples of Groups 2 or 3, disregard the color of the oil layer and report the sample as passing the test when the acid layer is not darker than the specified color standard.

Average Acid Wash Color

14. Precision and Bias 14.1 Precision data have not been established for all types of samples on which this test method is used. Limited cooperative tests were conducted in 1961, principally to establish equality with the previously used shaking procedure. Preci-

Repeatability Degrees 95 % of Repeat-

Reproducibility Degrees 95 % of Repro-

Freedom

ability

Freedom

ducibility

Benzene

1.4 6.1

11 12

0.75 1.85

9 10

2.34 4.47

Xylene

4.7 10.2

12 12

0.40 1.14

10 10

1.39 3.52

15. Keywords 15.1 acid wash color; aromatic hydrocarbons

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and ff net revised, either reepproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend. If you feel that your comments have not received e fair hearing you should make your views known to the ASTM Committee on Standards, 100 Barr Harbor Drive, West Conshohocken, PA 19428.

174

q~

Designation:D 849 - 97

Standard Test Method for Copper Strip Corrosion by Industrial Aromatic Hydrocarbons I This standard is issued under the fixed designation D 849; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (0 indicates an editorial change since the last revision or reapproval.

This standard has been approved for use by agencies of the Department of Defense. Consult the DoD Index of Specifications and Standards for the specific year of issue which has been adopted by the Department of Defense.

1. Scope 1.1 This test method determines the corrosiveness of industrial aromatic hydrocarbons to a copper strip.

4. Summary of Test Method 4.1 A polished copper strip is immersed in 200 mL of specimen in a flask with a condenser and placed in boiling water for 30 rain. At the end of this period, the copper strip is removed and compared with the ASTM Copper Strip Corrosion Standards.

NOTE l - - F o r a similar copper strip test applicable to other petroleum products, see M e t h o d D 130 a n d Test M e t h o d D 1838.

1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements, see Section 8.

2. Referenced Documents

2.1 A S T M Standards: B 152 Specification for Copper Sheet, Strip, Plate, and Rolled Bar2 D 130 Test Method for Detection of Copper Corrosion from Petroleum Products by the Copper Strip Tarnish Test3 D 1838 Test Method for Copper Strip Corrosion by Liquefied Petroleum (LP) Gases3 D 4790 Terminology of Aromatic Hydrocarbons and Related Chemicals4 2.2 Other Documents: OSHA Regulations, 29 CFR, paragraphs 1910. I000 and 1910.12005 2.3 Adjunct: ASTM Copper Strip Corrosion Standards (13 photolithed aluminum strips; includes Method D 130)6

5. Significance and Use 5.1 This test method is suitable for setting specifications, for use as an internal quality control tool, and for use in development or research work on industrial aromatic hydrocarbons and related materials. It also gives an indication of the presence of certain corrosive substances which may corrode equipment, such as acidic compounds or sulfur compounds. 6. Apparatus 6.1 Flask, 250-mL, of chemically resistant glass with flat bottom and vial mouth. 6.2 Glass Condenser, 30-ram, with the inside diameter of the condenser tube not less than 10 ram. A cork is used to connect the flask with the condenser. A condenser and flask with ground-glass joints may also be used. 6.3 Strip Polishing Vise, to hold the copper strip fLrmly without marring the edges. For convenient vises see Method D 130. 6.4 Water Bath, of convenient design, able to maintain boiling water such that the contents of the flask are submerged during the test. 7. Reagents and Materials 7.1 Wash Solvent--Any volatile, sulfur-free hydrocarbon solvent may be used provided that it shows no tarnish at all when tested at 100*C (212"F) for 1 h. Knock-test grade isooctane (Warning--See 8.2) is a suitable solvent and should be used in case of dispute. 7.2 Polishing Materials--Silicon carbide grit paper of varying degrees of fineness including 65-1xm (240-grit) paper or cloth; also a supply of 105-ttm (150-mesh) silicon carbide grain and pharmaceutical grade absorbent cotton (cotton wool). 7.3 Copper Strips--Use strips 12.5 mm (I/2 in.) wide, 1.5 to 3.0 mm (1/16 to 1/8 in.) thick, cut 75 mm (3 in.) long from smooth-surfaced, hard-tempered, cold-finished copper of 99.9+ % purity. Electrical bus-bar stock is generally suitable (hard-temper, cold-finished type-electrolytic tough pitch (ETP) copper conforming to UNS C11000 in Specification B 152. Drill a 3.2-mm (l/s-in.) hole approximately 3.2 mm (l/s in.) from one end in the center of the strip. The strips

3. Terminology 3.1 See Terminology D 4790 for definition of terms used in this test method. t This test method is under the jurisdiction of ASTM Committee D-16 on Aromatic Hydrocarbons and Related Chemicals and is the direct responsibility of Subcommittee DI6.0A on BTX Cyclohexane and Their Derivatives. Current edition approved June 10, 1997. Published September 1997. Originally published as D 849 - 145 T. Last previous edition D 849 - 93. 2 Annual Book of ASTM Standards, Vol 02.01. 3Annual Book of ASTM Standards, Vol 05.01. 4 Annual Book of ASTM Standards, Vol 06.04. 5 Available from Superintendent of Documents, U.S. Government Printing Office, Washington, DC 20402. 6 Available from ASTM Headquarters. Request PCN 12-401300-00. Names of suppliers in the United Kingdom can be obtained from the Institute of Petroleum. Two master standards are held by the IP for reference.

175

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D 849

may be used repeatedly but should be discarded when surfaces become deformed on handling. 7.4 Copper wire, soft, about 150 mm (6 in.) in length. 7.5 ASTM Copper Strip Corrosion Standards, consisting of reproductions in color of typical test strips representing increasing degrees of tarnish and corrosion. The reproductions are encased in plastic in the form of a plaque. Instructions for care and use are given on the reverse side of each plaque and in Method D 130.

reversing the direction. Clean all metal dust from the strip by rubbing vigorously with clean pads of absorbent cotton until a fresh pad remains unsoiled. When the strip is clean immediately attach the copper wire and immerse the strip in the specimen flask. NOTE 3mIt is important to polish the whole surface of the strip uniformly to obtain a uniformly stained strip. If the edges show wear (surface elliptical)they will likely show more corrosion than the center. The use of a vise will facilitateuniform polishing.

8. Hazards 8.1 Consult current OSHA regulations, supplier's Material Safety Data Sheets, and local regulations for all materials used in this test method. 8.2 Isooctane is Extremely Flammable. Harmful if inhaled. Vapors may cause flash fire. Keep away from heat, sparks, and open flame. Keep container closed. Use with adequate ventilation. Avoid buildup of vapors and eliminate all sources of ignition, especially non-explosion-proof electrical apparatus and heaters. Avoid prolonged breathing of vapor or spray mist. Avoid prolonged or repeated skin contact.

10. Procedure 10.1 Fasten the 150-ram (6-in.) length of soft copper wire through the hole provided near one end of the strip, taking care not to touch the strip with the fingers after polishing. Place the strip in the flask and add 200 mL of the sample. The specimen must not contain separated water. Filter through a dry filter paper, if necessary, to remove water. Connect the flask to the vertical reflux condenser by means of a properly bored cork stopper. It is absolutely necessary that a cork, not rubber, stopper be used, in order to avoid contamination of the specimen by sulfur from rubber stoppers. The copper wire may be allowed to extend into the condenser tube for convenience in removing the strip. Completely immerse the strip which should preferably lie flat and touch the flask only at the ends of the strip. Place the flask in the gently boiling water bath, and immerse the flask to the liquid line of the specimen within the flask. Remove the copper strip 30 rain from the time the flask was immersed in the bath. Do not touch the copper strip, but remove it by the wire that has been provided. Do not allow the strip to come in contact with separated water during any part of the test, since water causes bad local staining of the copper. If it is desired to preserve the strip for future reference, dip it immediately into white shellac or lacquer.

9. Preparation of Strips

9.1 Surface Preparation--Remove all surface blemishes from all six sides of the strip with silicon carbide grit paper of such degrees of fineness as are needed to accomplish the desired results efficiently. Finish with 65-ktm (240-grit) silicon-carbide paper or cloth, removing all marks that may have been made by other grades of paper used previously. Immediately immerse the strip in wash solvent from which it may be withdrawn for final polishing or in which it may be stored for future use. NOTE 2--As a practical manual polishingprocedure, place a sheet of the paper on a flat surface, moisten it with wash solvent, and rub the strip against the paper with a rotary motion, protecting the strip from contact with the fingers with an ashless filter paper. Alternatively,the strip may be prepared by use of motor-driven machines using appropriate grades of dry paper or cloth. 9.2 Final Polishing--Remove a strip from the wash solvent. Holding it in the fingers protected with ashless filter paper, polish first the ends and then the sides with the 150-mesh silicon-carbide grains picked up from a clean glass plate with a pad of absorbent cotton moistened with a drop of wash solvent. Wipe vigorously with fresh pads of absorbent cotton and subsequently handle only with stainless-steel forceps; do not touch with the fingers. Clamp in a vise and polish the main surfaces with silicon carbide grains on absorbent cotton. Rub in the direction of the long axis of the strip, carrying the stroke beyond the end of the strip before

11. Interpretation of Results 11.1 Compare the exposed strip with the ASTM Copper Strip Corrosion Standards described in 6.5. Hold the test strip and the Standard in such a manner that light reflected from them at an angle of approximately 45 ° will be observed. Report as passing strips shown in the Slight Tarnish catagory or better (IA or IB); all others shall be considered failures. 12. Precision and Bias 12.1 In the case of pass/fail data, no generally accepted method for determining precision and bias is currently available. 13. Keyword 13.1 copper corrosion test

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reepproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 100 Barr Harbor Drive, West Conshohocken, PA 19428.

176

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Designation: D 850 - 93 Standard Test Method for Distillation of Industrial Aromatic Hydrocarbons and Related Materials 1 This standard is issued under the fixed designation D 850; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (e) indicates an editorial change since the last revision or reapproval.

This test method has been approvedfor use by agencies of the Department of Defense. Consult the DoD Index of Specifications and Standards for the specific year of issue which has been adopted by the Department of Defense.

1. Scope 1.1 This test method covers the distillation of industrial aromatic hydrocarbons and related materials of relatively narrow boiling ranges from 30 to 250"C. 1.2 The values stated in SI units are to be regarded as the standard. 1.3 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements, see 5.6 and Section 6.

for use as an internal quality control tool, and for use in development or research work on industrial aromatic hydrocarbons and related materials. 4.2 This test method gives a broad indication of general purity and can also indicate presence of excessive moisture. It will not differentiate between products of similar boiling range.

5. Apparatus 5.1 FlaskTwA standard 200-mL side-tube, heat-resistant glass distillation flask as shown in Fig. l, conforming to the following dimensions:

. Referenced Documents Diameter of bulb, outside, mm Diameter of neck, inside, m m Height of flask, outside, m m Vertical distance from bottom of bulb outside to bottom of vapor-tube opening in neck, m m Length of side tube, m m Diameter of side tube, outside, m m Angle of side tube with vertical axis of bulb and neck, °

2.1 ASTM Standards: D 86 Method for Distillation of Petroleum Products: D 1078 Test Method for Distillation Range of Volatile Organic Liquids3 D 3437 Practice for Sampling and Handling Liquid Cyclic Products3 E 1 Specification for ASTM Thermometers4 E 133 Specification for Distillation Equipment 5 2.2 Other Document: OSHA Regulations, 29 CFR, paragraphs 1910.1000 and 1910.12006

76 + 1.5 21+1 179±3 120 ± 3 100 + 3 7-4-0.5 75±3

The flask does not comply with Flask C of Specification E 133. 5.2 ThermometermThe ASTM Solvents Distillation Thermometer used in the test shall be as prescribed in the specifications for the material being tested. If no thermometer is specified in the material specification, select one from Table 1 with the smallest graduations that will cover the entire distillation range of the material being tested. Table l lists several ASTM solvents distillation thermometers which are suitable for testing industrial aromatic hydrocarbons, and which meet the requirements of Specification E 1. 5.3 Condenser--Either of the following two condensers may be used: 5.3.1 The condenser specified in Method D 86. 5.3.2 As an alternative, the condenser tube may consist of a straight glass tube 600 to 610 mm in length and 12 mm in inside diameter, of standard wall thickness (about 1.25 mm) with the exit end cut off square and ground flat. It shall be set in a cooling trough so that at least 380 mm of the tube is in contact with the water. Clearance between the condenser tube and any parallel side of the trough shall be not less than 19 mm. The water in the cooling trough shall be maintained at 10 to 20"C. This may be done by adding ice to the water or by circulating chilled water through the trough. The trough

3. Summary of Test Method 3.1 The distillation of industrial aromatic hydrocarbons and related materials is carded out via a carefully controlled distillation wherein temperature readings are noted for the first drop of distillate and when 5, 10, and each additional 10 up to 90, and 95 % of the sample has distilled over. The temperature corresponding to the dry point is also noted. 4. Significance and Use 4.1 This test method is suitable for setting specifications, t This test method is under the jurisdiction of ASTM Committee D-16 on Aromatic Hydrocarbons and Related Chemicals and is the direct responsibility of Subcommittee DI6.0A on Benzene, Toluene, Xylenes, Cyclohexane, and Their Derivatives. Current edition approved April 15, 1993. Published June 1993. Originally published as D 850 - 45. Last previous edition D 850 - 9 I. 2 Annual Book of ASTM Standards, Vols 05.01 and 06.04. 3 Annual Book of ASTM Standards, Vol 06.04. 4 Annual Book of ASTM Standards, Vols 05.03 and 14.03. 5 Annual Bt~Tk of ASTM Standards, Vols 05.03 and 14.02. 6 Available from Superintendent of Documents, U.S. Government Printing Office, Washington, DC 20402.

7 A flask suitable for use is Coming Flask No. 4680, or its equivalent.

177

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the burner shall be adjusted so as to produce an entirely blue flame. In case of dispute concerning results obtained with gas heat versus electric heat, gas heat shall be accepted as the standard.

I.D.

NOTE 1: Caution--Superheating of the flask can cause erroneous results and is more likely to occur with electric heaters than with bunsen burners as heat sources. This problem is discussed in the section on Preparation of Apparatus in Test Method D 1078.

6. Hazards 6.1 Consult current OSHA regulations and supplier's Material Safety Data Sheets for all materials used in this test method.

E

i

i FIG. 1

TABLE 1 ASTM Thermometer NO. 39C 40C 41C 42C 102C 103C 104C 105C

7. Sampling 7.1 Sampling should follow safe rules in order to adhere to all safety precautions as outlined in the latest OSHA regulations. Refer to Practice D 3437 for proper sampling and handling of aromatic hydrocarbons analyzed by this test method. 7.2 The sample under test shall be transparent and free of separated water. Any separated water may ordinarily be eliminated by care in pouring the 100-mL specimen (9.1) into the graduated cylinder. If necessary, any separated water or cloudiness may be removed by filtration, in which case the following precautions shall be taken: Use a soft paper through which the specimen filters rapidly, avoid drafts, cover the funnel with a watch glass, and filter at least 200 mL from which to take the 100 mL for distillation. Dehydration (that is, removal of dissolved water) is not permissible. Note, however, that certain materials, especially benzene, may absorb traces of water that can be significant with respect to this test. When it can be shown that failure to pass this distillation test is due to the presence of dissolved water, it shall be permissible, if mutually agreeable to the purchaser and the seller, to dry the specimen by any method agreed to by both the purchaser and the seller.

Distillation Flask

ASTM Thermometers for Distillation Test of Industrial Aromatic Hydrocarbons Name

Range, oC

Subdivision, *C

solvents distillation solvents distillation solvents distillation solvents dlstlllat=on solvents d=stdlatlon solvents distillation solvents distillation solvents distillation

48 to 102 72 to 126 98 to 152 95 to 255 123 to 177 148 to 202 173 to 227 198 to 252

0.2 0.2 0.2 0.5 0.2 0.2 0.2 0.2

shall be so mounted that the condenser tube is set at an angle of 75* with the vertical. 5.4 Receiver--A graduate of the cylindrical type, of uniform diameter, with a pressed or molded base and a lipped top. The cylinder shall be graduated to contain 100 mL, and the graduated portion shall be not less than 178 nor more than 203 mm in length. It shall be graduated in single millilitres and each fifth mark shall be distinguished by a longer line. It shall be numbered from the bottom up at intervals of l0 mL. The overall height of the graduate shall not be less than 248 nor more than 260 mm. The graduations shall not be in error by more than 1 mL at any point on the scale. The bottom l-mL graduation may be omitted. The receiver complies with Graduate B of Specification E 133. 5.5 Support for Flask--A sheet of 3 to 6-mm hard insulation board 152 mm square with a circular hole in the center, supported on a circular metal shield enclosing the bunsen burner, and approximately 50 mm higher than the top of the burner. For tests of benzene and toluene, the hole shall be 25 mm in diameter; for tests of materials boiling above toluene but mostly below 145"C, the hole shall be 38 mm in diameter, and for higher boiling materials, it shall be 50 mm in diameter. 5.6 Heater--An electric heater or a bunsen burner, fully adjustable and capable of giving sufficient heat to distill the product at the required rate. When a bunsen burner is used,

8, Assembly of Apparatus 8.1 Assemble the apparatus as shown in Fig. 2. Mount the flask on the insulation board of appropriate dimensions, with the side tube extending through a tightly fitting cork stopper about 50 mm into the condenser tube. 8.2 Support the distillation thermometer in the neck of the flask by means of a cork stopper with the thermometer vertical and centered in the neck of the flask and in such a position that the top of the bulb (or top of contraction bulb if present) is level with the lowest point of juncture between the side tube and the neck of the flask (see Fig. 3). 8.3 Place the burner directly under the center of the hole in the insulation board. NOTE 2--As an alternative, the apparatus specified in Method D 86, modified by the use of the flask and thermometer as specified in 8. l and 8.2, may be used.

9. Procedure 9. l Carefully measure a 100-mL specimen of the material to be tested in the 100-mL graduated cylinder at room temperature and transfer to the distillation flask, draining the cylinder at least 15 s. This is preferably done before mounting the flask in position, in order to prevent liquid 178

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Thermometer

.

.

n'

'nsulotlon~~- / ~ St0nd z~--i~ \ FIG. 2

JHJwo,.rTa,./

Apparatus Assembly for Distillation Test

from entering the side arm. Connect the flask to the condenser and apparatus, assembled as described in Section 8. Do not rinse out the graduated cylinder used to measure the sample for distillation, but place under the lower end of the condenser tube to receive the distillate. Heat the flask slowly, especially after ebullition has begun, so as to allow the mercury column of the thermometer to become fully expanded before the first drop distills over. Regulate the rate of heating so that the ring of condensing vapor on the wall of the flask reaches the lower edge of the side arm in not less than 90 s, and preferably approximately 120 s, from the start of the rise of the vapor ring. The total time from the start of heating until the first drop falls into the receiver should be not less than 5 nor more than 10 min. Avoid major changes in heating rate. Even operation is best gained through experience with the method. When distillation starts, adjust the receiver to allow condensation to flow down its inner wall to prevent loss by spattering; then adjust the heater to

FIG. 3

IIII

continue the distillation at the rate of 5 to 7 mL/min (about 2 drops/s). Maintain this rate, and continue the distillation to dryness. The total yield of distillate when testing close boiling benzenes, toluenes, and xylenes shall be not less than 97 %, and when testing wider boiling refined products and light oils, shall be not less than 95 %; otherwise, the test shall be repeated. 9.2 Take the temperature reading when the first drop of distillate falls into the receiving cylinder and report as the initial boiling point (IBP). If necessary, take additional readings when 5, 10, each additional 10 up through 90, 90, and 95 % of the specimen has just distilled over. Take a final reading when the liquid just disappears from the flask, and report this reading as the dry point temperature. When testing crude materials, a decomposition point, rather than a dry point, may be obtained. When a decomposition point is reached at the end of a distillation, the temperature will frequently cease to rise and begin to fall. In this case, take the

Position of Thermometer in Distillation Flask

179

~

D 850 TABLE 3 BoilingPointsof Hydrocarbons

temperature at the decomposition point as the maximum temperature observed. The decomposition point may also be indicated by the appearance of heavy fumes in the flask. Should that occur, record the temperature at the time the bulb of the flask becomes substantially full of fumes. If a decomposition rather than a dry point is observed, so note when recording results. 9.3 Observe and record the following additional data at the time and place of the distillation test: 9.3.1 Correction for inaccuracy of the thermometer, and 9.3.2 Barometer reading and temperature of the barometer. The observed barometric pressure shall be corrected by reference to standard tables and reported in terms of millimetres of mercury at 0*C.

Barometric Pressure, oC Benzene Ethylbenzene Pyridine Toluene

m-Xylene o-Xylene p-Xylene

observed 50 % boiling point and the true boiling point at 760 mm as given in Table 3. 11. Report 11.1 Report observed temperatures to the nearest 0. l'C, in a manner conforming to the specifications of the material tested. If no definite manner of reporting is specified, report the corrected temperatures at each observed volume, and report the volume percentages of residue, recovery, and distillation loss. 11.2 In the ASTM specifications where Test Method D 850 is cited, the distillation range is defined as follows:

10. Temperature Corrections 10.1 Corrections of temperature should be applied in the following cases: 10.1.1 When required by the specifications, 10.1.2 When there is any question of compliance with the specifications, and 10.1.3 When tests of the sample are to be checked against results obtained by another investigator. 10.1.4 When corrected temperatures are reported, notation should be made of the type of corrections applied. 10.2 Inaccuracy of ThermometermThis correction shall be obtained by calibration of the thermometer used in the test and applied to the observed thermometer reading.

Distillation range, *C ffi DPT-IBP

where: DCPT = the temperature at the decomposition point, and IBP = the initial boiling point.

correction shall be applied to the observed temperature after correcting for inaccuracy of the thermometer and is determined by the following equation:

12. Precision and Bias 12.1 The following criteria should be used for judging the acceptability of results (95 % confidence) on distillation range: 12.1.1 Repeatability--Duplicate results by the same operator should be considered suspect if they differ by more than the following amounts:

(1)

where: C = the correction in degrees Celsius, A, B = constants from Table 2, P = the measured barometric pressure in millimetres of mercury corrected to 0*C. 10.4 Combined Corrections--If the overall distillation range of the sample does not exceed 2"C, a combined correction for thermometer inaccuracy and barometric pressure may be made on the basis of the difference between the TABLE 2

Benzene Toluene Xylene

Material

A

B

0.0427 0.0463 0.0490 0.0497 0.0490 0.0492 0.0493

0.000025 0.000027 0.000028 0.000029 0.000029 0.000029 0.000029

0.0493 0.0530

0.000029 0.000032

'C 0.16 0.23 0.26

12.1.2 Reproducibility--Results submitted by each of two laboratories should be considered suspect if the two results differ by more than the following amounts:

Constants for Correction for Variations in Barometric Pressure (600 to 800-ram Hg)

Benzene Toluene Ethylbenzene o-Xylene m-Xylene p-Xylene M=xed xylenes Grade xylene Solvent naphtha Hi-flash solvent

(2)

where DPT is the dry point temperature and IBP is the initial boiling point. 11.3 In cases where decomposition points occur, the distillation range is defined as: Distillation Range *C = DCPT - IBP

10.3 Variation from Standard Barometric Pressure--This

C = [A + {B x (760- P)}] x (760 - P)

80.1 136.2 115.5 110.6 139.1 144.4 138.3

"C Benzene Toluene Xylene

0.42 0.47 0.42

12.1.3 The bias of this test method has not been addressed because no standard reference materials were available. 13. Keywords 13.1 aromatic hydrocarbons; distillation

180

o 8so

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reappreved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments wit/receive careful consideration at a meeting of the responsible technical committee, which you may attend. If you fee/that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103.

181

(~l~

Designation: D 852 - 9S Standard Test Method for Solidification Point of Benzene 1 This standard is issued under the fixed designation D 852; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last rcapproval. A superscript epsilon (0 indicates an editorial change since the last revision or re,approval.

NOTE l--Solidification point is distinguished from freezing point which is described in Test Method D 1015. An interpretation of tool percent purity in terms of freezing point is given in Test Method D 1016.

1. Scope 1.1 This test method covers the determination of the solidification point of benzene. 1.2 The following applies to all specified limits in this test method: for purposes of determining conformance with this test method, an observed value or a calculated value shall be rounded off "to the nearest unit" in the last right-hand digit used in expressing the specification limit, in accordance with the rounding-off method of Practice E 29. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements, see Section 7.

4. Summary of Test Method 4.1 Solidification point is measured by noting the maximum temperature reached during a controlled cooling cycle after the appearance of a solid phase. 5. Significance and Use 5.1 This test method may be used as a criteria for determining the purity of benzene. The closer the solidification point reaches that of pure benzene, the purer the sample. 6. Apparatus 6.1 Benzene Container, a test tube 15 mm in outside diameter and 125 mm in length. 6.2 Air Jacket, a standard test tube 25 mm in outside diameter and 150 mm in length. 6.3 Ice Bath, a I-L beaker, or similar suitable container, having an effective depth of at least 127 mm and filled with chipped or shaved ice. 6.4 Stirrer, consisting of a l-ram wire (copper or stainless steel) or a 2-ram glass rod with one end bent into a circular form at right angles to the shaft so that it will move freely in the annular space between the thermometer stem and the wall of the smaller test tube. 6.5 Thermometer, an ASTM Benzene Freezing Point Thermometer having a range from 4.0 to 6.0"C and conforming to the requirements for Thermometer 112C as prescribed in Specification E 1. 6.6 Insulation--Dry absorbent cotton or glass wool.

2. Referenced Documents

2.1 ASTM Standards: D 1015 Test Method for Freezing Points of High-Purity Hydrocarbons 2 D 1016 Test Method for Purity of Hydrocarbons from Freezing Points2 D 1193 Specification for Reagent Water 3 D 3437 Practice for Sampling and Handling Liquid Cyclic Products 4 E I Specification for ASTM Thermometers 5 E 29 Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications6 2.2 Other Document: OSHA Regulations, 29CFR, paragraphs 1910.1000 and 1910.12007 3. Definition 3.1 solidification point--an empirical constant defined as the temperature at which the liquid phase of a substance is in approximate equilibrium with a relatively small portion of the solid phase.

7. Hazards 7.1 Consult the latest OSHA regulations, supplier's Material Safety Data Sheets, and local regulations for all materials used in this test method. 8. Sampling 8.1 Sample the material in accordance with Practice D 3437.

t This test method is under the jurisdiction of ASTM Committee D-16 on Aromatic Hydrocarbons and Related Chemicals and is the direct responsibility of Subcommittee DI6.0A on Benzene, Toluene, Xylenes, Cyclohexane, and Their Derivatives. Current edition approved June 10, 1986. Published August 1996. Originally published as D 852 - 45. Last previous edition D 852 - 87 (1991). 2 Annual Book of A S T M Standards, Vol 05.01. a Annual Book of A S T M Standards, Vol i 1.01. 4 Annual Book of A S T M Standards, Vol 06.04. 5 Annual Book of A S T M Standards, Vol 14.03. e Annual Book of A S T M Standards, Vol 14.02. 7 Available from Superintendent of Documents, U.S. Government Printing Office, Washington, DC 20402.

9. Preparation of Apparatus 9.1 Fit the smaller test tube with a two-hole cork stopper. Through one hole insert the thermometer up to the 4.0"C mark; through the other hole insert shaft of the stirrer. 9.2 Place a '/8-in. (3.2-ram) layer of dry absorbent cotton or glass wool in the bottom of the larger test tube. 182

(@) D 852 mometer reading closely. The temperature will fall to a minimum, then rise to a maximum, remain constant at this maximum for approximately 1 min, and then fall again (Note 2). The minimum temperature is due to super-cooling before solidification starts and shall not be more than 0.7"C below the maximum. Record the maximum constant temperature observed to the nearest 0.01°C and designate it as "wet" (Note 3). NOTE 2--If distinct minimum and maximum points are not evident, or if the temperature does not remain constant at the maximum for at least 30 s, the determination shall be repeated. NOTE 3nThe precision can be increased to +0.01"C by using a magnifying glass that ensures a reading perpendicular to the stem of the thermometer. In such cases it may be necessary to correct for stem exposure, that under ordinary conditions this correction will be less than 0.01*C.

9.3 Insert the smaller test tube up to the lip into a cork stopper or annular ring of cork that just fits into the mouth of the larger test tube. 10. Calibration of Thermometer 10.1 Calibration of ASTM thermometer 112C is accomplished with the small scale etched on the lower portion of the thermometer. Prepare an ice bath by filling a small Dewar flask with crushed ice made from Type I or Type II water (as specified in Specification D 1193) and add just enough chilled Type I or Type II water to make a slurry. Immerse the thermometer in the ice bath, allow 5 min for the system to reach equilibrium and read the thermometer. Solidification point values are subsequently adjusted by adding (or subtracting) the number of degrees the thermometer is below (or above) O.O0°C.

12. Report 12.1 Results shall be reported on the anhydrous basis. Since the determination is actually made on water-saturated benzene, the solidification point shall be corrected to the anhydrous basis by adding 0.090C to the observed maximum temperature following the minimum. Corrections for accuracy of the thermometer shall be made.

11. Procedure 11.1 Saturate the sample of benzene with water as follows: Place 7 or 8 m L of the sample in the smaller test tube, add 1 drop of water, and shake the tube and contents vigorously. 11.2 Insert the stopper carrying the thermometer and stirrer into the smaller test tube and adjust the thermometer so that the 4.0"C mark is just even with the top of the stopper. 11.3 Cool the smaller test tube and contents rapidly to about 6°C in the ice bath, while stirring. Wipe dry the outside of the smaller test tube and insert it into the larger test tube. Place the assembled tubes in the ice bath. 11.4 Stir the benzene continuously and observe the thor-

13. Precision and Bias 13.1 Duplicate determinations on the same specimen should not differ by more than 0.02°C (Note 3). 14. Keywords 14.1 benzene; solidification point

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and ff not revised, either respproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend, ff you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 100 Bars" Harbor Drive, West Conshohockan, PA 19428.

183

1[~ Designation: D 853 - 97

Standard Test Method for Hydrogen Sulfide and Sulfur Dioxide Content (Qualitative) of Industrial Aromatic Hydrocarbons 1 This standard is issued under the fixed designation D 853; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last rcapproval. A superscript epsilon (~) indicates an editorial change since the last revision or reapproval.

This test method has been approvedfor use by agencies of tbe Department of Defense to replace Method 5311 of Federal Test Method Standard No. 141A and for listing in the DoD Index of Specifications and Standards.

1. Scope 1.1 This test method covers the determination of the hydrogen sulfide and sulfur dioxide content (qualitative) of industrial aromatic hydrocarbons. 1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements see Section 6.

. Referenced Documents 2.1 A S T M Standards: D 850 Test Method for Distillation of Industrial Aromatic Hydrocarbons and Related Materials2 D 3437 Practice for Sampling and Handling Liquid Cyclic Products2 D 4790 Terminology of Aromatic Hydrocarbons and Related Chemicals2 2.2 Other Documents: OSHA Regulations, 29 CFR, Paragraphs 1910.1000 and 1910.12003 3. Terminology 3.1 See Terminology D 4790 for Definition of terms used in this test method.

5.2 This test method is a qualitative one for hydrogen sulfide (H2S) and sulfur dioxide (SO2). It should not be considered quantitative. It gives an indication of the presence of H2S or SO2, or both, which may cause objectionable odors or be corrosive to certain materials of construction.

6. Reagents 6.1 Lead Acetate Solution (saturated). 6.2 Potassium Iodate Solution (100 g/L)--Dissolve 10 g of potassium iodate (KIO3) in water and dilute to 100 mL. 6.3 Starch Paper--Dip strips of filter paper in starch solution and dry. 7. Hazards 7.1 Consult current OSHA regulations, supplier's Material Safety Data Sheets, and local regulations for all materials used in this test method. 8. Sampling 8.1 Sampling should follow safe rules in order to adhere to all safety precautions as outlined in the latest OSHA regulations. Refer to Practice D 3437 for sampling and handling of aromatic hydrocarbons analyzed by this test method. 9. Procedure 9.1 Make a qualitative test for H2S and SO2, at the time of performing the distillation test, see Test Method D 850. This is done by hanging a strip of filter paper moistened with the lead acetate solution and a strip of starch paper moistened with the potassium iodate solution on the end of the condenser tube. The strips are placed so that they are suspended in the upper part of the receiving cylinder so that drops of condensate pass between the strips without touching them. If, at the end of the test, the lead acetate paper shows discoloration, H2S is present but not SO2. If the lead acetate paper shows no discoloration but the starch iodate paper develops a blue color, SO2 is present but not H2S. If neither paper shows discoloration, neither H2S nor SO2 is present.

4. Summary of Test Method 4.1 This test method involves a qualitative color test for HzS and SO2 that utilizes filter paper containing lead acetate and starch paper containing potassium iodate. The test is performed when carrying out the Test Method D850 distillation test. 5. Significance and Use 5.1 This test method is suitable for setting specifications on industrial aromatic hydrocarbons and related materials and for use as an internal quality control tool.

10. Precision and Bias 10.1 In the case of pass/fail data, no generally accepted method for determining precision and bias is currently available.

I This test method is under the jurisdiction of ASTM Committee D-16 on Aromatic Hydrocarbons and Related Chemicals and is the direct responsibility of Subcommittee DI6.0A on Benzene, Toluene, Xylenes, Cyclohexane, and Their Derivatives. Current edition approved June 10, 1997. Published September 1997. Originally published as D 853 - 45 T. Last previous edition D 853 - 91. 2 Annual Book of ASTM Standards, Vol 06.04. 3 Available from Superintendent of Documents, U.S. Government Printing Office, Washington, DC 20402.

11. Keywords 11. l hydrogen sulfide; sulfur dioxide

184

o 8s3 The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned In this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility, This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reepproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration st a meeting of the responsible technical committee, which you may attend, if you feel that your comments have not received a fair hearing you should make your vieWs known to the ASTM Committee on Standards, 100 Barr Harbor Drive, West Conshohockan, PA 19428.

185

~TI~ Designati°n: D 972 - 91e1

An American Nat0onalStandard

Standard Test Method for Evaporation Loss of Lubricating Greases and Oils This standard is issued under the fixed designation D 972; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (e) indicates an editorial change since the last revision or reapproval. This lest method has been adopted for use by government agencies to replace MelhtM 3.~I o.fl"edcral Test Method Stamhml No. 7911~ ~o NOTE--The legend in Fig. 2 was corrected editorially in December 1992.

1. Scope 1.1 This test method covers the determination of the loss in mass by evaporation of lubricating greases and oils for applications where evaporation loss is a factor. Evaporation loss data can be obtained at any temperature in the range from 100 to 150"C (210 to 300°F). 1.2 The values stated in either SI units or inch-pound units shall be regarded separately as standard. The values stated in each system may not be exact equivalents of the other; therefore each system must be used independently of the other, without combining values in any way. 1.3 This standard does not purport to address all of the

safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

from this test method and service performance has not been established. 4.2 The test can be run at any agreed upon temperature between 100 and 150°C (210 to 300°F). NOTE l - - T h e specified flow o f air, 2.58 _+0.02 g/rain, (2L/min at

standard temperature and pressure), assumes dry air. It is not known that the original work involveddry air but it has since been shown that this can be a factor in reproducibilityand should be addressed. A dew point of less than 10"C at standard temperature and pressure will be satisfactory.

5.

Apparatus 4

5.1 Evaporation Cell, (Fig. 1) as described in Annex AI. 5.2 Air Supply System, capable of supplying to the cell the required flow of air free of entrained particles. A 400 mm (16-in.) length of 25-ram (l-in.) diameter pipe packed with glass wool has been found satisfactory for filtering the air. 5 . 3 0 i l B a t h , shown in Fig. 2 and described in Annex Al. NOTE 2--Other constant-temperaturebaths may be used if they are equivalentin heat capacityand thermal gradientcharacteristicsto the oil bath.

2. Referenced Documents

2.1 A S T M Standards: A 240 Specification for Heat-Resisting Chromium and Chromium-Nickel Stainless Steel Plate, Sheet, and Strip for Pressure Vessels 2 E 1 Specification for ASTM Thermometers 3

5.4 Thermometers--For tests at 100°C (210°F) an ASTM Thermometer having a range from 95 to 103°C (204 to 21801=') and conforming to the requirements for Thermometer 22C-86 (22F-86) as prescribed in Specification E I shall be used. For tests at temperatures above 100°C (210"F) an ASTM Precision Thermometer conforming to the requirements for Thermometer 67C-86 (67F-86) as prescribed in Specification E 1 is suitable. 5.5 Flowmeter--A rotameter calibrated to deliver air at a rate of 2.583 +0.02 g/rain between 15 and 30°C (60 and 85°F) (2 L/rain at standard temperature and pressure). It shall be furnished with a needle valve and mounted as shown in Fig. 1.

3. Summary of Test Method 3. I The weighed sample of lubricant in an evaporation cell is placed in a bath maintained at the desired test temperature. Heated air is passed over its surface for 22 h. The evaporation loss is calculated from the loss in mass of the sample. 4. Significance and Use 4.1 The loss of volatile materials from greases and oils can adversely effect the original performance characteristics of a lubricant and therefore could be a significant factor in evaluating a lubricant for a specific use. Such volatiles can also be considered contaminants in the environment in which the lubricant is to be used. Correlation between results

6. Procedure for Greases 6.1 Weigh the clean grease-sample cup and hood (Fig. 3) to the nearest I rag. Remove the hood and fill the cup with sample, taking care to avoid occlusion of air. Smooth the surface level with the rim of the cup with a straight-edged spatula. Remove with a clean cloth any grease which may remain on the rim or threads of the cup. Thread the hood tightly onto the cup without disturbing the smoothed grease

nThis test method is under the jurisdiction of ASTM Committee D.2 o n Petroleum Products and Lubricants and is the direct respondbility of Subcommittee D02.G on Lubricating Grease. Current edition approved Sept. 15, 1991. Published November 1991. Originally published as D 972 - 48 T. Last previous edition D 972 - 86. 2Annual Book of ASTM Standards, Vols 01.03 and 01.04. 3 Annual Book of ASTM Standards, Vois 05.03 and 14.03.

4 Apparatus for this test method is available from Koehler Instrument Co., 1595 Sycamore Ave., Bohemia, LI., NY i 1716 and Stanhope-Seta LTD, Park Close, Englefield Green, Egham, Surrey TW20 OXD, England.

186

~

O 972 AIR OUTLET ORIFICE

O.Do TUBING MINIMUM LENGTH

A B

{APPROXIMATELY 7 TURNS]

COVER TIGHTENING

\

== [--]---Ioll

L.Iou,oL¢,,~- "7 = J . - T-'--';--~=!

W$

FLOWMETER

AIR AdJuSTMENT

c

~

t

V ?

FRONT VIEW

AIRINL£T~ FIG. 1 Evaporation Test Cell Key

mm

A B C

6.4 1830 13

FIG. 2 in. 72 0.5 ::1:0.1=25

II

JJ

Assembled Apparatus

Key

mm

o

2,,130

s0.012s

in.

E F G

3.2 1.3/1.8 73.1

0.125 0.051/0.072 2.875

Tolerances:_+0,4mm (:t:0.0156 in.) unless otherwise noted

surface. Weigh the assembly and record the mass of the sample to the nearest 1 rag. 6.2 With cover in place, but without the hood and sample cup attached, allow the evaporation cell to acquire the temperature of the bath (controlled to +0.5"C (±I'F)) at which the test is to be made by immersing the cell in the bath, as shown in Fig. 2. Allow the cell to remain in the bath at least I/2 h before beginning the test. During this period, allow clean air to flow through the cell at the prescribed rate, 2.58 __.0.02 g/min (2 L/min at standard temperature and pressure), as indicated by the rotameter. Remove the cover, thread the weighed hood and sample cup into place, and replace the cover. Tighten the three knurled cover-tightening screws securely to prevent air leakage under the cover. Pass clean air through the cell at the prescribed rate for 22 h ± 5 rain. 6.3 Remove the assembled sample cup and hood from the cell. At the end of the 22-h period allow to cool to room temperature. Determine the mass of the sample to the nearest 1 mg.

8. Calculation 8.1 Calculate the evaporation loss of the sample as follows: Evaporation loss, mass % = [(S - W)/S] x lO0 where: S = initial mass of sample, g, and W = mass of sample, g, after the test. 9. Precision and Bias 9.1 The precision ofthis test method is not known to have been obtained in accordance with currently accepted guidelines (in Committee D-2 research report RR: D02-1007, "Manual on Determining Precision Data for ASTM Methods on Petroleum Products and Lubricants"). 9.2 The precision of this test method as determined by statistical examination of inteflaboratory results is as follows: 9.2.1 Repeatability--The difference between two test results, obtained by the same operator with the same apparatus under constant operating conditions on identical test material, would in the long run, in the normal and correct operation of the test method, exceed the following value only in one case in twenty: 0.025M where: M = mean of two values 9.2.2 Reproducibility--The difference between two single and independent results obtained by different operators working in different laboratories on identical test material would, in the long run, in the normal and correct operation

7. Procedure for Oils 7.1 Weigh the clean oil-sample cup and hood (Fig. 4) to the nearest 1 rag. Transfer, by means of a pipet, 10.00 + 0.05 g of sample to the cup. Assemble the cup and hood, being careful not to splash oil on the underside of the hood. Weigh the assembly and record the net sample mass to the nearest 1 mg. 7.2 Evaporate the sample as described in 6.2 and 6.3: 187

~

t~

D 972

H

EDUCTION TUBE

.1000

T

J P

K

~HOOD

M

-p

L

-O KR.

~"SAMPLE

CUP

K

----R

Q FIG. 3 Key H I J K L M N

N

AMPLE CUP

U FIG. 4

Grease Sample Cup mm 66 7.62 6.35 1.6 5 33 40

Q

Oil Sample Cup

in. Key mm 2.625 O 5.40/5.65 0.3125 P 1.45/1.70 0.25 O 54.64/54.89 0.0625 R 6.9/7.4 0.1875 S 3 1.3125 T 4 1.6 U 58.7 Tolerances::t:0.4mm(4-0.0156 In.) unless otherwisenoted

in. 0.213/0.223 0.057/0.067 2.15/2.16 0.27/0.29 0.125 0.16 2.3

suring evaporation loss of lubricating greases and oils has no bias because the value of loss in mass is defined only in terms of this test method.

of the test method, exceed the following value only in one case in twenty: 0.10M

where: M = mean of two values 9.3 Bias--The procedure in this test method for mea-

10. Keywords 10.1 evaporation; grease; oil; oil bath; rotameter; volatiles

ANNEX

(Mandatory Information) A1. APPARATUS4 200 g each), hood, eduction tube, and orifice shall be constructed of 18 % chromium, 8 % nickel alloy steel. A suitable material is an alloy steel conforming to Grade S, Type 304, of Specification A 240. To facilitate removal and separation of the cup and hood for inserting the sample and weighing, the sample cup shall be threaded to the hood and this in turn to the eduction tube of the cover. A 1.1.3 The cover of the cell shall be made airtight.

A 1.1 Evaporation Cell with attachments conforming with the dimensional tolerances as indicated in Figs. 1 and 2 and capable of being supported upright in the oil bath. Other structural details are as follows: A 1.1.1 The body and cover of the cell shall be constructed of stainless steel and the air-heating coil of tinned copper tubing. A1.1.2 The sample cups (recommended maximum mass

188

~

D 972

A I.2 Oil Bath of sufficient depth to allow submersion of the evaporation cell to the proper level and capable of being controlled at the desired test temperature within +0.5"C (+l'F), with a maximum variation throughout the bath of +0.5°C (+ l°F). Circulation of the oil heating medium by a pump or stirrer is recommended. Sufficient heat capacity shall bc provided to return the bath to the required temper-

ature within 60 min after immersion of the cell. The bath shall be provided with a temperature well such that the thermometer used can bc inserted to its proper immersion depth. The bath shall be arranged so that there are no drafts or wide fluctuations in temperature around the evaporation cell.

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reepproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Heedquartars. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend, ff you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103.

189

Designation: D 976 - 91 ( R e a p p r o v e d 1995) ~

Ill~ I % ~ i i l l i l J

An AmerkT,an National Standard

Designation: 364/84

Standard Test Methods for Calculated Cetane Index of Distillate Fuels ~ This standard is issued under the fixed designation D 976; the number immedmtely following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. This is also a standard of the Institute of Petroleum issued under the fixed designation IP 218. The final number indicates the year of last revision.

These lest methods have been approved by the ~TJonsoring committees and accepted b), the cooperating societies in accordance with estabhshed procedures. This standard has been approved [or use by agencies of the Department t f De.[bnse. Consult the DoD Index of Specifications and Standards for the spect[ic year qf'ts.wte which has been adopted by the Department o[ DeJense ~a No'lit--Section 7 was added editorially in October 1995.

1. Scope 1.1 The Calculated Cetane Index formula represents a means for directly estimating the ASTM cetane number of distillate fuels from API gravity and mid-boiling point. The index value, as computed from the formula, is termed the Calculated Cetane Index. 2 1.2 The Calculated Cetane Index is not an optional method for expressing ASTM cetane number. It is a supplementary tool for predicting cetane number when used with due regard for its limitations. 1.3 The Calculated Cetane Index formula is particularly applicable to straight-run fuels, catalytically cracked stocks, and blends of the two. 1.4 This standard does not purport to address all of the

D 287 Test Method for API Gravity of Crude Petroleum and Petroleum Products (Hydrometer Method) 4 D 1298 Test Method for Density, Relative Density, (Specific Gravity), or API Gravity of Crude Petroleum and Liquid Petroleum Products by Hydrometer Method 4 D 4737 Test Method for Calculated Cetane Index by Four Variable Equation 5

3. Significance and Use 3.1 The Calculated Cetane Index is a useful tool for estimating ASTM cetane number where a test engine is not available for determining this property. It may be conveniently employed for approximating cetane number where the quantity of sample is too small for an engine rating. In cases where the cetane number of a fuel has been initially established, the index is useful as a cetane number check on subsequent samples of that fuel, provided its source and mode of manufacture remain unchanged.

safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. NOTE l--This test method is temporarily retained because the proposal to the U.S. EPA to control diesel fuel aromatics concentrations via a 40 Calculated Cetane Index minimum is based on the correlation between Test Method D 976 and aromatics concentration. Test Method D 4737 is the preferred method as estimator of cetane number. Test method D 976 is intended to be letter balloted for withdrawal from the book of standards in 1993.

4. Equation for Calculated Cetane Index 4. I The Calculated Cetane Index is determined from the following equation: Calculated cetane index = -420.34 + 0.016 G 2 + 0.192 G log M + 65.01 (log 34)2 - 0.0001809 M2. or Calculated cetane index = 454.74 - 1641.416 D + 774.74 D2 -0.554 B + 97.803 (log B)2. where: G = API gravity, determined by Test Method D 287 or D 1298, M = mid-boiling temperature, *F, determined by Test Method D 86 and corrected to standard barometric pressure, D ---density at 15"C, g/mL, determined by Test Method D 1298, and

. Referenced Documents

2.1 A S T M Standards: D 86 Test Method for Distillation of Petroleum Products 3

t These test methods are under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and are the direct responsibility of Subcommittee D02.E on Burner, Diesel, and Gas Turbine Fuel Oils. Current edition approved March 15, 1991. Published May 1991. Originally published as D 976 - 66. Last previous edition D 976 - 80 (1990). 2 A method of calculating cetane index was developed by the Diesel Fuels Division. Coordinating Fuel and Equipment Research Committee of the Coordinating Research Council. See It. D. Young. "Methods for Estimating Cetane Number," Proceedmg.~, PPIRA, Am. Petroleum Inst., Vol. 30 M [111], 1950. This method was revised in 1960 by Research Division I of Committee D-2 to conform to the revised Method D 613. a Dintut/Boo~ eft ASTM Slandald~, Vo[ 05.01.

Annual Book qfASTM Standards, Vol 05.01. s Ammal Bool~ of ASTM Standards, Vol 05.03.

4

190

(@'~ D 976 *..£

*_c CALCULATED CETANE INDEX

49

300- -.570

Basedon

Equation: Calculated CI =-420.34 + 0.016 G 2 + 0.192 G log M + 65.01 (log M) 2 - 0.0001809 M 2 CO~tCI~ON ,oR e t . g u t x . l t P~[ssus[

~*-,~.,~¢,o,

,o, , , ,

47

i/280 -

..:=--530 :;,,

~t O b ~54 55t-51o

ze

0.80

/

270,

-520

260.

251o -5oo

/

G25.&~2

65

,o .........................

.60

/ /

- g90

/

0.81

/ / /

"55 /

41

"540

/

.0.79

43

-.560 -5.50

290//

/

/

2.50, Lu80 -

~7o 5

0.82

240.

'd

"

-~6o i /

39

/

o. 9

/

--°i

• ~5 ~

/

2302

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.~ 37

O.84 ~ z m

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-3o 33

-~3o i

i

0.86 210

'

-410

31 J~O0

29 ~_ .... 200

27

-390

-=0.89 EXAMPLE.

~0.90

2.5 _~o.9%

MID B PT, 550 "F AI APt CRAVITY ] 3 . 0

?D0 RM HK

CORII£CTION FOR MID B. PT, - 1.19 x 6 - 7 . 1 4 CORRECTED HID B P T - 550"~ + 7 . I A ° F - 557.14~F CALC, CETA/IE INDEX (NOMOGRAPII) - &8.5 CALC. CETANE INDEX (FORMIILA) - 48.52

-38o

19o-f -F-37o

29

NOTE--The Calculated Cetane Index equation represents a useful tool for estimating cetane number. Due to inherent limitations in its application, Index values may not be a valid substitute for ASTM Cetane Numbers as determined in a test engine. FIG. 1 N o m o g r a p h for Calculated C e t a n e Index (ECS-1 M e t e r B a s i s - - M e t h o d O 6 1 3 z)

B = mid-boiling temperature, *C, determined by Test Method D 86 and corrected to standard barometric pressure.

5. Limitations of Equation 5.1 The Calculated Cetane Index equation possesses certain inherent limitations which must be recognized in its application. These are: 5.1.1 It is not applicable to fuels containing additives for raising cetane number. 5.1.2 It is not applicable to pure hydrocarbons, synthetic fuels, such as certain products derived from shale oils and tar sands, alkylates, or coal-tar products. 5.1.3 Substantial inaccuracies in correlation may occur if used for crude oils, residuals, or products having a volatility of below 500 F end point.

4.2 Calculated Cetane Index values for distillate fuels may be conveniently determined by means of the alignment chart in Fig. l, 6 rather than by direct application of the equation. The method of using this chart is indicated by the illustrative example thereon. ¢'Copies of the Nomograph for Calculated Cetane Index, 8'/2 by 11 in. in size, are available at a nominal cost from ASTM, 1916 Race St., Philadelphia, Pa. 19103. Request Adjunct No. 12-409760-12. 7 Aroma/Book o f A S T M Standards, Vol 05.04.

191

~') D 976 6. Precision

correlation may be greater for fuels whose cetane numbers are outside this range. Correlation is best for straight-run and catalytically cracked distillates and blends of the two, and least satisfactory for blends containing substantial proportions of thermally cracked stocks.

6.1 Correlation of index values with ASTM cetane number is dependent to a great extent upon the accuracy of determination of both API gravity and midboiling point. 6.2 Within the range from 30 to 60 cetane number, the expected correlation of the Calculated Cetane Index with the ASTM cetane number will be somewhat less than +2 cetane numbers for 75 % of the distillate fuels evaluated. Errors in

7. Keywords 7.1 cetane; cetane index; diesel fuel

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned m this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reappreved or withdrawn. Your comments are invited either for revision of thts standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend. If you fee/that your comments have not received a fair hearing you should make your vtews known to the ASTM Committee on Standards, 100 Barr Harbor Drive, West Conshohocken, PA 19428.

192

Designation: D 1078 - 97

®

Designation: 195/81 Standard Test Method for Distillation Range of Volatile Organic Liquids I This standard is issued under the fixed designation D 1078; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapprovai. A superscript epsilon (~) indicates an editorial change since the last revision or reapproval.

This test method was adopted as a joint ASTM-IP standard in 1986. This test method has been approved for use by agencies of the Department of Defer~se to replace Method 4301.1 of Federal Test Method Standard No. 141a and for listing in the DoD Index of Spec~qcations and Standards.

distillation flask, disregarding any liquid on the side of the flask. 3.1.3 decomposition point--the thermometer reading that coincides with the first indications of thermal decomposition of the liquid in the flask. 3.2 Definitions of Terms Specific to This Standard: 3.2.1 final boiling pointmthe maximum thermometer reading obtained during the test. 3.2.1.1 Discussion--This usually occurs after the evaporation of all liquid from the bottom of the flask. The term "maximum temperature" is a frequently used synonym. 3.2.2 end point 5 minutesmthe thermometer reading obtained 5 rain after the 95 % distillation point if no dry or final boiling point occurs.

1. Scope 1.1 This test method covers the determination of the distillation range of liquids boiling between 30 and 350"C, that are chemically stable during the distillation process. 1.2 This test method is applicable to organic liquids such as hydrocarbons, oxygenated compounds, chemical intermediates, and blends thereof. 1.3 For hazard information and guidance, see the supplier's Material Safety Data Sheet. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Specific hazard statements are given in Section 7.

4. Summary of Test Method 4.1 A 100-mL specimen is distilled under conditions equivalent to a simple batch differential distillation. The temperature of the mercury in the thermometer is equilibrated with that of the refluxing liquid before the distillate is taken over. Boiling temperatures observed on a partial immersion thermometer are corrected to standard atmospheric pressure to give true boiling temperatures.

2. Referenced Documents

2.1 A S T M Standards: D 86 Test Method for Distillation of Petroleum Products 2 E 1 Specification for ASTM Thermometers 3 E 133 Specification for Distillation Equipment 4 E 180 Practice for Determining the Precision of ASTM Methods for Analysis and Testing of Industrial Chemicals 5 E 299 Test Method for Trace Amounts of Peroxides in Organic Solvents5

5. Significance and Use 5. l This test method provides a method of measurement of distillation range of volatile organic liquids. The relative volatility of organic liquids can be used with other tests for identification and measurement of quality. Therefore, this test method provides a test procedure for assessing compliance with a specification. 5.2 This test method also provides an empirical value of residue, solvent recovery capacity, and loss (or non-recovery) on heating. Organic liquids are used as solvents in many chemical processes. As the relative volatility, residual matter and recovery capability affect the efficiency of these processes, this test method is useful in manufacturing control.

3. Terminology 3.1 Definitions: 3.1.1 initial boiling point--the temperature indicated by the distillation thermometer at the instant the first drop of condensate leaves the condenser tube. 3.1.2 dry pointmthe temperature indicated at the instant the last drop of liquid evaporates from the lowest point in the

6. Apparatus 6.1 Distillation Apparatus--See Condenser and Cooling Bath section, Figs. 1 and 2, and Metal Shield or Enclosure for Flask section of Specification E 133. 6.2 Distillation Flasks, 200-mL of borosilicate glass complying with the specifications given in Distillation Flask section, Fig. 3, and Flask C of Specification E 133.

t This test method is under the jurisdiction of ASTM Committee D-I on Paint

and Related Coatings, Materials, and Appficafions and is the direct responsibility of Subcommitlee D01.35 on Solvents, Plasticizen, and Chemical Intermediates. Current edition approved July 10, 1997. Published September 1997. Originally published as D 1078 - 49 T. Last previous edition D 1078 - 95. 2 Annual Book of ASTM Standards, Voi 05.0 !. 3Annual Book of ASTM Standards, VUl 14.03. 4 Annual Book of ASTM Standards, Vol 14.02. 5 Annual Book of ASTM Standards, Vol 15.05.

193

D lozs NOTE l--Liquid superheating in a new flask may be prevemed by depositing a small amount of carbon in the bottom of the flask. This may be accomplished by heating and decomposing a pinch of tartaric acid in the bottom of the flask. The flask is then prepared for use by washing with water, rinsing with acetone, and drying. 6.3 Source of Heat--An adjustable gas burner or electric heater so constructed that sufficient heat can be obtained to distill the product at the uniform rate specified in Section 8. For narrow-range (less than 2oc) liquids, an electric heater may be used only if it has been proven to give results comparable to those obtained when using gas heat. (See Section 9 for factors that cause superheating, and Appendix X I for a discussion on the use of electric heaters.) 6.4 ReceiverwA 100-mL cylinder graduated in l-mL subdivisions and having an overall height of 250 to 260 mm. 6.5 Thermometers--Partial immersion thermometers as listed in Table 1, conforming to Specification E 1. Both bore corrections and either ice or steam standardization corrections are recommended.

TABLE 1 ASTM Thermometer Number

Thermometers

IP

Range, °C

Subdivision,

°C

2C A 3C ~t 14C

62C~ 73CA

- 5 to +300 - 5 to +400 38 to 82

1.0 B 0.1

37c

~8

- 2 to +52

o.2

24 to 78 48 to 102 72 to 126 98 tO 152 95 tO 255 123 tO 177 148 to 202 173 to 227 198 to 252 223 to 277 248 to 302

0.2 0.2 0.2 0.2 0.5 0.2 0.2 0.2 0.2 0.2 0.2

38C 39C 4{)(3 41C 42CA 102C 103C 104C 105C 106(3 107C

78C 79(3 80C 81C 82CA 83C 84C 85C 86C 87C 88C

A These thermometers have more temperature tag than the other thermometers listed herein and are not satisfactory for use with narrow-boilingrange ,quids. e I tO 301°C; 1.5°C above 3010C.

7. Hazards 7.1 Precaution--Certain solvents and chemical intermediates, particularly, but not only ethers and unsaturated compounds, may form peroxides during storage. These peroxides may present a violent explosion hazard when the chemical is distilled, especially as the dry point is approached. When peroxide formation is likely because of chemical type or length of storage, the material should be analyzed for peroxides (See Test Method E 299.) and if they exist in hazardous concentrations, appropriate precautions should be taken such as destroying the peroxide before distillation, shielding, or destroying the sample and not running the test. 7.2 Most organic solvents and chemical intermediates will burn. In the operation of the distillation apparatus, use a suitable catch pan and shielding to contain spilled liquid in the event o f accidental breakage o f the distillation flask. 7.3 Provide adequate ventilation to maintain solvent vapor concentrations below the lower explosive limit in the immediate vicinity of the distillation apparatus, and below the threshold limit value in the general work area.

that the neck of the flask is vertical and the vapor tube extends into the condenser tube a distance of 25 to 50 mm. Have the bottom of the flask resting firmly in the 1i/4 or 11h-in. (32 or 38-ram) opening of the upper asbestos cement board. No~ 3--For low-boiling materials, cool the apparatus to room temperature before starting the test. 8.4 Fill the condenser bath with water of the appropriate temperature shown in Table 2. NOTe 4---When distilling pure compounds always ensure that the

condenser bath temperature is above the crystallizing point of the compound. 8.5 Adjust the temperature o f the appropriate portion of the sample to the applicable temperature shown in Table 2. 9. Procedure 9.1 Using the graduated receiver measure 100 + 0.5 m L of the temperature-adjusted sample. Remove the flask from the apparatus and transfer the fresh specimen directly to the flask, allowing the graduate to drain for 15 to 20 s. NOTE 5--For viscous liquids, a longer drainage period may be necessary to complete the transfer of the specimen to the flask, but the drainage time should not exceed 5 min. Do not allow any of the specimen to enter the vapor tube.

8. Preparation of Apparatus 8.1 Clean and dry the condenser tube by swabbing with a piece of soft lint-free cloth attached to a wire or cord or by any other suitable means. 8.2 Use the thermometer listed in the material specification for the product under study. If no thermometer is specified, select one from Table 1 with the smallest graduations that will cover the entire distillation range of the material. Center the thermometer into the neck of the flask through a tight-fitting cork stopper so that the upper end of the contraction chamber (or bulb if Thermometer 2C or IP thermometer 62C is used) is level with the lower side of the vapor tube at its junction with the neck of the flask. (See Fig. 1 of Method D 86.) NOTE 2--1t is far more important that the greatest volume of mercury be immersed in the refluxing zone than that the immersion mark on the thermometer be placed at any specificpoint.

9.2 Connect the flask to the condenser and insert the thermometer as described in 8.2. Place the receiver, without drying, at the outlet of the condenser tube in such a position that the condenser tube extends into the graduate at least 25 m m but does not extend below the 100-mL mark. If the initial boiling point of the material is below 70°C, immerse the cylinder in a transparent bath and maintain at a temperature of 10 to 20°C throughout the distillation. Place a flat cover on the top of the graduate to prevent condensed TABLE 2

8.3 Insert the vapor tube o f the distillation flask into the condenser, making a tight connection with a well-rolled cork. Adjust the position of the asbestos boards or heater shield so 194

Temperatures

Initial Boiling

C,ondonsoro

Point, °C

°C

,~L,nple, °C

Below 50 50 to 70 70 to 150 Above 150

0to3 OtolO 25 to 30 35 to 50

0to3 10 to 20 20 to 30 20 to 30

~

D 1078

moisture from entering the graduate. 9.3 A certain amount of judgment is necessary in choosing the best operating conditions to get acceptable accuracy and precision for materials having different distilling temperatures. As a general guide, it is recommended that: 9.3.1 For materials having an initial boiling point below 150"C, the following conditions be established: 9.3.1.1 Heat Shield--Hole size, 32-mm diameter. 9.3.1.2 Heating Rate--Time from application of heat to first drop of distillate, 5 to 10 rain, and time of rise of vapor column in neck of flask to side arm, 21/2 to 31/2 rain. 9.3.2 For materials having an initial boiling point above 150"C, the following conditions should be established: 9.3.2.1 Heat Shield--Hole size, 38-ram diameter. 9.3.2.2 Heating Rate--Time from application of heat to first drop ofdistillate, 10 to 15 rain, and time of rise of vapor column in neck of flask to side arm, sufficiently rapid to permit collection of the first drop of distillate within 15 rain of the start of heating. 9.4 Adjust the heat input so that the distillation proceeds at a rate of 4 to 5 mL/min (approximately 2 drops per second), and move the receiving cylinder so that the tip of the condenser tube touches one side of the cylinder after the In'st drop falls (initial boiling point). Record the readings of the distillation thermometer after collecting 5, I0, 20, 30, 40, 50, 60, 70, 80, 90, and 95 mL of distillate. 9.5 Without changing the heater setting, continue distillation beyond the 95 % point until the dry point is observed. Record the temperature at this point as the dry point (Section 3). If a dry point is not obtained (that is, if active decomposition should occur before the dry point is reached, as evidenced by a rapid evolution of vapor or heavy fumes; or if there is liquid remaining on the bottom of the flask when the maximum temperature is observed on the distillation thermometer), record this fact. 9.6 When a dry point cannot be obtained, report as the end point the maximum temperature observed on the distillation thermometer or final boiling point (Section 3). When active decomposition is encountered, the rapid evolution of vapor and heavy fumes is usually followed by a gradual decrease in the distillation temperature. Record the temperature and report as the decomposition point (Section 3). If the expected drop in temperature does not occur, record the maximum temperature observed on the distillation thermometer 5 rain after the 95 % point has been reached, and report as "end point, 5 rain." This notation shows that a true end point could not be reached within the given time limit. In any event, the end point should not exceed 5 rain after the 95 % point. 9.7 Read and record the barometric pressure. 9.8 After the condenser tube has drained, read the total volume of distillate and record it as recovery. The total yield of distillate from a material having a distillation range of 10*C or less should be not less than 97 % for nonviscous liquids. For viscous liquids and materials having a wider distillation range than 10*C, a yield of 95 volume % is satisfactory. If yields are not obtained within these limits, repeat the test.

9.9 If any residue is present, cool to room temperature and pour into a small cylinder graduated in 0. l-mL subdivisions. Measure the volume and record it as residue. Record the difference between 100 and the sum of the residue plus recovery as distillation loss.

10. Factors Causing Superheating 10.1 In general, any condition whereby the temperature surrounding the vapor exceeds the temperature of the vapor in equilibrium with the liquid will cause superheating. Specific factors conducive to superheating are as follows, and should be avoided: 10.2 Flame in Contact with the Flask--The applied gas flame should be prevented from contacting more than the specified portion of the flask by the following procedures: 10.2.1 Maintain the correct overall dimensions and specified hole diameter of the asbestos cement board. The hole must be perfectly circular, with no irregularities. 10.2.2 Use a board that is free of cracks and checks. 10.2.3 Set the flask snugly in the hole in the upper insulating board. 10.3 Application of Heat--Attention should be given to burner placement, position, and character of flame, as follows: 10.3.1 Apply the source of heat directly beneath the flask. Any variation would result in heating a larger portion of surrounding air to a higher temperature than that of the flask. 10.3.2 The flame should not have a larger cross section than is necessary, and should be nonluminous. 10.3.3 Place the burner at a level such that the complete combustion area of a nonluminous flame is approximately 3/4 in. (20 ram) below the board. 10.4 Extraneous Heat Source--An extraneous source of heat such as sunlight falling directly on the flask can cause superheating. 10.5 Condition of Equipment--Observe caution in employing the apparatus for immediate reuse. For low-boiling materials, cool the heating unit to room temperature before starting the test. 10.6 Use of Electric Heaters--Electric heaters generally cause superheating. These should be used only after they have been proven to give results comparable to those obtained when using gas heat. The superheating effect obtained from electric heaters may be minimized, but not completely eliminated, by selecting a heater that, by its design, concentrates the heating elements to a minimum area, and contains a minimum amount of ceramic material in its overall construction. The fulfillment of these requirements will reduce, but not completely eliminate, the amount of extraneous heat radiating around the perimeter of the asbestos-cement board on which the distillation flask is placed. 6 (See Appendix X 1 for a more complete discussion of the problems encountered in the use of electric heaters.) 6 The sole source of supply of the Lo-Cap heater known to the committee at this time is Precision Scientific Co., Chicaso, IL. If you are aware of alternative suppliers, please provide this information to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, l which you may attend.

195

~') D 1078 11. Calculations 11.1 Thermometer Bore CorrectionmApply the corrections for any variations in the bore of the thermometer as given by the calibration. 11.2 Thermometer Bulb Shrinkage Correction~Apply the correction for shrinkage of the mercury bulb of the thermometer as determined by any change in its ice or steam point where applicable. Other means can be employed, such as the use of a platinum-resistance thermometer or a National Bureau of Standards thermometer. 11.3 Barometer CorrectionmAfter applying the corrections for thermometer error, correct each reading for deviation of the barometric pressure from normal by adding algebraically the correction calculated as follows: 11.3.1 For values of Kin degrees Celsius per millimetre of mercury Correction = K(760 - P) where: K = rate of change of boiling point with pressure, in degrees Celsius per millimetre, as given in Table 3 (Note 6), and P = barometric pressure in millimetres of mercury at standard temperature. 11.3.2 For values of K in degrees Celsius per millibar: Correction = K(1013 - P)

where: K = rate of change of boiling point with pressure, in degrees Celsius per millibar, as given in Table 3 (Note 6), and P = barometric pressure in millibars at standard temperature and pressure. NOTE 6 - - F o r other pure compounds not listed in Table 3, the value K should be obtained from the literature. For narrow-boiling hydrocarbon materials, the value of K may be assumed as 0.00012 times the normal boiling point on the absolute temperature scale.

l 1.4 If the overall distillation range of the sample does not exceed 2°C, combined thermometer (bore irregularities and bulb shrinkage) and barometric corrections may be made on the basis of the difference between the observed 50 % boiling point and the true boiling point at 760 mm as given in Table 3.

TABLE 3

Change of Boiling Point with Pressure

Compound

Value of K, °C per mm Hg at Boiling Point

K, °C per Boiling Point mbar at at 760 mm He, Boiling Point °C

Acetone n-Amyl alcohol n-Amyl acetate Aromatic solvent naphtha

0.039 0.041 0.046 0.049

0.029 0.031 0.036 0.037

56.1 138.0 149.5 ...

Benzene Isol~Jtyl acetate n-Butyl acetate see-Butyl acetate Isobutyl a l c o ~ n-Butyl alcohol sec-Butyl alcohol

0.043 0.045 0.045 0.045 0.036 0.037 0.035

0.032 0.035 0.035 0.064 0.027 0.028 0.026

80.1 117.3 126.1 112.4 107.9 117.7 99.5

Diacetocle ak:ohol

0.050

0.037

O~thy~ne¢yc~

0.050

0.037

2~.0

Dipropylene glycol

0.051

0.038

232.8

Ethyl acetate Ethyl alcohol Ethylene glycol 2-Butoxyethenol 2-Ethoxyethanol 2-Ethoxyethyl acetate

0.041 0.033 0.045 0.047 0.044 0,046

0.030 0,025 0.033 0.035 0.033 0.035

77.2 78.3 197.6 171.2 135.1 156.3

Hexylene glycol n-Hexyl acetate

0.045 0.050

0.033 0.037

197,1 171.6

Isophorone

0.057

0.043

215.3

Methyl alcohol Methyl ethyl ketone Methyl isoamyl acetate Methyl Isoamyl ketone Methyl Isobutyl carblnol Methyl laobutyl ketone

0.033 0.04,3 0,048 0,048 0.641 0.646

0.025 0.032 0.036 0.036 0.030 0.035

64.5 79.6 146.2 144.9 131.8 116.2

Perctdoroethylene Isopropyl alcohol

0.648 0.033

0.036 0.025

121.2 82.3

tsopropylaomte

o.641

0.030

38.6

Propyleno ~ Pyridlne

0.043 0.646

0.032 0.035

187.6 115.4

Toluene Trlchloroethylene

0.046 0.043

0.035 0.032

110.6 87.1

Vinyl acetate

0.640

0.050

72.7

Xylene (mixed isomers)

0.049

0.037

...

that have a wide boiling range at elevated temperatures. The values shown for the different solvents may be used as examples of the precision obtainable with this test method at the 95 % confidence level. For a better estimate of precision for a particular case, a cooperative study should be made on the compound or product of interest. 13. I.I Repeatability---Tworesults, each the mean of two runs, obtained by the same operator should be considered suspect if they differ by more than the values shown in Table 4 for a material with similar boiling range and 50 % point. 13.1.2 Reproducibility---Tworesults, each the mean of two runs, obtained by operators in different laboratories should be considered suspect if they differ by more than values shown in Table 4 for a material with a similar boiling range and 50 % point. 13.1.3 BiasmBias of this test method has not been determined.

12. Report 12.1 Report the results in a manner conforming with the specifications of the material tested. If no definite manner of reporting is specified, report the corrected temperatures at each observed volume, and report the volume percentages of residue, recovery, and distillation loss. 13. P r e c i s i o n 7 13.1 The precision of this test method is based on three interlaboratory studies involving ten laboratories and several solvents. It was established that, in general, the precision improves with increasing purity and decreasing boiling point of the material being tested, while it is poorest for mixtures

14. Keywords 14.1 distillation range; solvents

v Supporting data are available from ASTM Headquarters. Request RR: D01-1051.

196

~ TABLE 4

D 1078

Summary o f Prsciaion A

Acetate Ester of Acetonea

Dlethylane Glycol Monoethyl Ether Initial Boiling Point, *C

Reproducibility

55.87 ± 0.09 0.10 0,09 0.42

215.33 ± 0.31 0.77 0.87 1.53

M I Value Checking Limits Repeatability Reproducibility

68.03 ± 0.07 0.07 0.15 0.32

218.24 + 0.24 0.21 0.58 1.16

Mean Value Checking Limits Repeatability Reproducibility

56.36 ± 0.11 0.27 0.24 0.51

220.03 ± 0.29 0.46 0.57 1.35

Mean Dp---Averege Ibp Checking Limits Repeatability Reproducibility

0.49 0.29 0.26 0.66

Mean Value Checking Umita Repeatability

Glycol Mixture

Xylene-Pseudocumene

Mineral Spirits

190.70 ± 0.42 0.76 0.51 1.92

141.03 ± 0.52 0.50 0.34 2.35

163.68 ± 0.35 1.13 2.13 2.19

192.63 ± 0.35 0.40 0.34 1.67

146.18 ± 0.37 0.56 0.81 1.75

175.02 ± 0.26 0.93 0.48 1.20

202.51 ± 0.74 0.57 0.77 3.36

168.75 ± 0.57 0.80 1.20 2.70

200.35 ± 0.77 1.22 0.80 3.50

11.8 0.95 0.93 3.88

27.8 0.95 1.25 3.59

36.7 1.67 2.28 4.13

50-mL Point, °C

Dry Point, *C

Distillation Range, *C 4.7 0.90 1.04 2.04

A All values are at the 95 % confidence level and were calculated in accordance with Practice E 180. e ASTM thermometer 39C was used.

APPENDIX

(NonmandatoryInformation) X1. DISCUSSION ON THE USE OF ELECTRIC HEATERS WHEN APPLYING TEST METHOD D 1078/IP 195 TO THE DETERMINATION OF THE DISTILLATION RANGE OF NARROW RANGE (<2°C) PURE COMPOUNDS Xl.1 Test Method D 1078/IP 195, in the hands of a competent operator using properly designed equipment, has been found over the years to be a valuable tool in detecting the presence of low-boiling and high-boiling impurities in relatively pure compounds. X1.2 In recent years many laboratories, for reasons of safety and convenience, have eliminated the availability of natural or artiflcal gas, with the resulting trend toward the exclusive use of electric heaters in place of gas burners. The use of electricity instead of gas as the source of heat, coupled with the application of this test method to materials of extremely high purity and narrow distillation ranges (2"C or less), has resulted in the distortion of the dry point. This distortion effect can be illustrated by comparing the distillaTABLE X1.1

tion range resultsusing gas and electricheat on a sample of high-purity methanol (Table Xl.l). The purity of the methanol employed was establishedby gas chromatography and other instrumental procedures. XI.3 The higher dry point obtained with the electric heater is due to the large amount of extraneous heat radiating around the distillation flask which in turn is due to the relatively large area of the distillation board exposed to the heating elements of the electric heater. For example, the heating elements of the electric heated cover an area of 63.5 by 76 mm whereas the flame of a properly adjusted gas burner can be concentrated to an area no larger than the 32-mm hole of the supporting asbestos cement (or ceramic) board. This means that when the heating elements of the electric heater are brought up to sufficient temperature to effect the proper distillation rate of the methanol, a relatively large area of the board also is exposed to the heat of these elements so that as the end of the distillation is approached, a considerable amount of heat is being radiated from the board to the air surrounding the distillation flask. This hot air surrounding the flask is sufficient to cause a distortion of the dry point as the last drop of liquid is vaporized from the bottom of the flask. Conversely, the ability to concentrate the gas flame to only the 32-ram exposed area of the flask minimizes the extent of the extraneous heat radiating from the board, which, in turn, eliminates the distortion of the dry

Cornpadson of Gas Versus Electric Heat Electric Heater6

Gas Heat

Range

Range Determination 1:

Initialboilingpoint Dry point Determination 2: Initial boiling point Dry point Mean range

64.5 64.8

0.3

64.5 66.0

1.5

64.5 64.9

0.4

64.5 66.4

1.9

. . .

0.35

. . .

1.7

197

lib D 1078 point from this cause. This conclusion was substantiated by results from the following experiment: The board with the 32-ram hole was replaced by a 190.7 by 190.7-ram stainless steel plate in which a 32-ram hole had been cut. Four turns of 6.4-mm copper tubing with sufficient inlet and outlet leads were silver-soldered to the underside of the plate so that water could be circulated through the tubing during the course of the distillation. With this "water-cooled board" substituted for the standard board, only the heat from the electrical elements immediately under the 32-ram outlet could reach the distillation flask. The heat emanating from the outer perimeter of the heater was dissipated by the water circulating through the tubing on the underside of the board, as evidenced by the ability to hold one's finger on top of the "water-cooled board" during the course of the distillation. Using the same high-purity methanol employed in the previous experiment, distillation ranges were determined using gas heat, electric heat, and electric heat with the "water-cooled board" substituted for the standard board. These results are given in Table XI.I. X 1.4 The results from the above experiment demonstrate the effect the extraneous radiant heat from the electric heater had on the dry point, and also suggest a means whereby this effect could be greatly reduced. XI.5 Despite the fact that the use of a "water-cooled board" in conjunction with an electric heater eliminated the extraneous radiant heat surrounding the distillation flask, it is evident from the results in Table X 1.2 that the dry point obtained when using the electric heater and "water-cooled board" was still significantly higher than the dry point obtained when using gas heat. The assumption was made that this "residual" interference to the dry point was caused by infrared radiation from the glowing electric heating elements. This assumption has been supported by the following experimental evidence: The bottom of a standard 200-mL distillation flask was coated with a 38-ram diameter circle of black ceramic marking ink. The black ink was in turn fired into the glass by heating the bottom of the flask to a dull-red heat with a gas-oxygen glass blowtorch. The presence of this black coating on the bottom of the flask

would absorb any infrared radiation emanating from the electrical heating elements, thus preventing it from affecting the bulb of the thermometer at the end of the distillation. Distillation ranges were then determined on the same methanol as used in the previous experiments following Test Method D 1078/IP 195, except that in one case a standard 200-mL fiask was used with an electric heater plus the "water-cooled board," and in the other case, the specially prepared "black bottom" 200-mL flask was employed. Both of these special conditions were compared to the standard procedure using gas heat. The results of this experiment, given in Table X 1.3, show that the use of the "black-bottom flask" in conjunction with the electric heater and "watercooled board" causes a significant lowering of the dry point which confirms the theory that infrared radiation emanating from the electric heating elements causes a slight distortion of the dry point. X 1.6 The above discussion and experimental evidence are presented to show how and why the use of electric heater causes a distortion of the dry point when carrying out the procedure as specified in Test Method D 1078/IP 195. Although this distortion is of a minor nature, and therefore of little importance when applying this test method to compounds or mixtures which have distillation ranges of 5"C or more, the effect becomes significant when the method is applied to narrow range (2"C or less) pure compounds. It is the further objective of this discussion to suggest to those laboratories equipped with only electricity, a technique whereby the distillation range results obtained with electric heaters may be made equivalent to those obtained with gas heat. X1.7 The sponsoring subcommittee of this test method has not had the opportunity to apply this technique to a sufficiently large number of compounds over a wide range of boiling temperatures to warrant including it as a part of Test Method D 1078/IP 195; and is, therefore, presenting it for information purposes only. Comments are solicited from those attempting to employ the suggestions contained in this report as well as other ideas that might be employed to equate the use of electric heat with gas heat.

198

(~ D 1078 TABLE Xl.2

C o m p a r i s o n of Elecffic Heat Plus W a t e r - C o o l e d Board to G a s Heat Gas Heat

Electric Heats Range

Determination 1: Initial boiling point Dry point Determination 2: Initial boiling point Dry point Mean range

Range

Range

64.5 64.8

0.3

64.5 66.1

1.6

64.5 65.0

0.5

64.6 64,9 ...

0.3

64.5 65.9 ...

1.4

64.5 65.1 ...

0.6

0.3

T A B L E X1.3

1,5

0.55

E f f e c t o f I n f r a r e d R a d i a t i o n o n Dry Point Electric Heaters with Water-Cooled Board and Standard Rask

Gas Heat Range Determination 1: Initial boiling point Dry point Determination 2: Initial boiUng point Dry polm Mean range

Electric Heats plus Water-Cooled Board

Electric Heatera with Water-Cooled Board and Back-Bottom Flash

Range

Range

64.5 64.8

0.3

64.5 65.1

0.6

64.6 64.8

0.2

64.5 64.9 ...

0.4

64.6 65.2 . ..

0.6

64.6 64.9 ...

0.2

0,35

0.6

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are ant/rely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and ff not revised, either reepproved or withdrawn. Your comments are Invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at 8 meeting of the responsible technical committee, which you may attend, ff you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 100 Barr Harbor Drive, West Conshohockan, PA 19428.

199

0.25

(~[~ Designation:D 1133-94 Standard Test Method for Kauri-Butanol Value of Hydrocarbon Solvents I This standard is issued under the fixed designation D 1133; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (e) indicates an editorial change since the last revision or re.approval.

This test method has been approvedfor use by agencies of the Department of Defense to replace Method 5191 of Federal Test Method Standard No. 141a. Consult the DoD Index of Specifcations and Standards for the specific year of issue which has been adopted by the Department of Defense.

1. Scope 1.1 This test method covers the determination of the relative solvent power of hydrocarbon solvents used in paint and lacquer formulations. This test method is suitable for use with solvents having an initial boiling point over 40"C and a dry point under 300"C when determined in accordance with the procedures in Note 1.

4. Significance and Use 4.1 The kauri-butanol value is used as a measure of solvent power of hydrocarbon solvents. High kauri-butanol values indicate relatively strong solvency. 5. Apparatus

5.1 Water Bath, a clear-glass vessel, maintained at 25 + I*C. Alternatively, a room maintained at 25 + I*C may be used. 5.2 Volumetric Flask, 200-mL capacity. 5.3 Erlenmeyer Flask, 250-mL capacity. 5.4 Buret, 50-mL capacity. 5.5 Print Specimen--A sheet of white paper having on it black 10 on 12 point print, No. 31 Bruce old style type.

NOTE l mMethod D 86 is used to determine the initial boiling point and dry point for mineral spirits and similar petroleum solvents. Test Method D 1078 is used for pure compounds and narrow boiling range cuts.

1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

6. Reagents 6.1 Purity of ReagentsmReagent grade chemicals shall be

1.3 For specific hazard information and guidance, consult the supplier's Material Safety Data Sheet.

used in all tests unless otherwise specified. Unless otherwise indicated, it is intended that all reagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, where such specifications are available.4 Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination. 6.2 Kauri-Butanol SolutionSmPlace in a 3-L flask 400 g of clean, pale, bold kauri resin of Grade XXXX, XXX, or XX ground to pea-size or smaller. Add, while agitating vigorously, 2000 g of n-butyl alcohol, (conforming to Specification D 304). Shake on a mechanical shaker until the resin goes into solution, warming to about 55"C, if necessary to aid solution. If a mechanical shaker is not available, fit the flask with a reflux condenser and heat on a steam bath until all of the kauri resin is dissolved. Permit the solution to stand 48 h and then clarify by filtering through a Biichner funnel with suction, using double filter paper and changing as frequently as necessary. 6.3 Standard Toluene conforming to Specification D 841 for use as a high-solvency standard. 6.4 Heptane-Toluene Blend consisting of 25 _ 0.1%

2. Referenced Documents 2.1 A S T M Standards." D 86 Test Method for Distillation of Petroleum Products 2 D 304 Specification for n-Butyl Alcohol (Butanol) 3 D 611 Test Methods for Aniline Point and Mixed Aniline Point of Petroleum Products and Hydrocarbon Solvents2 D 841 Specification for Nitration Grade Toluene 3 D 1078 Test Method for Distillation Range of Volatile Organic Liquids3

3. Terminology 3.1 Definition: 3.1.1 kauri-butanol valuemof a solvent, the volume in millilitres at 25"C of the solvent, corrected to a defined standard, required to produce a defined degree of turbidity when added to 20 g of a standard solution of kauri resin in normal butyl alcohol. The kauri resin solution is standardized against toluene, which has an assigned value of 105, and a mixture of 75 % n-heptane and 25 % toluene on a volume basis, which has an assigned value of 40.

( Reagent Chemicals, American Chemical Society Specifcations, American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed by the American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville, MD. s Prepared kauri-butanol solutions are available from the Chemical Service Laboratories, 5543 Dyer St., Dallas, TX 75206.

' This test method is under the jurisdiction of ASTM Committee D-I on Paint and Related Coatings, Materials, and Applications and is the direct responsibility of Subcommittee D01.35 on Solvents, Plasticizers, and Chemical Intermediates. Current edition approved April 15, 1994. Published June 1994. Originally published as D I 133 - 50 T. Last previous edition D I 133 - 90. 2 Annual Book of ASTM Standards, Vol 05.01. 3 Annual Book of ASTM Standards, Vol 06.04.

200

~

D 1133 the water bath at 25 ± I'C. Fill the 50-mL buret with the solvent being tested and titrate the solvent into the Eflenmeyer flask with constant swirling while maintaining the mixture in the flask at 25"C. Gradually reduce the successive amounts of solvent added as the end point is approached. The end point is reached when the sharp outlines of 10-point print (see 5.5) placed directly beneath the water bath and observed through the liquid are obscured or blurred, but not to the point where the print becomes illegible. Check the temperature in the flask immediately after the end point has been reached and if over 26"C or under 24"C, repeat the titration. Designate the volume of solvent, in millilitres, to produce turbidity as C.

toluene and 75 ± 0.1% n-heptane on a volume basis, for use as a low-solvency standard. The heptane shall conform to the requirements for knock test grade n-heptane prescribed in Table l of Test Methods D 611. NOTE 2--The blend of 25 + 0.1% toluene and 75 :t: 0.1% heptane can be prepared in any way that will give the desired accuracy. The following technique is adequate: Bring the toluene and heptane and a calibrated 200-mL volumetric flask to the same temperature, preferably in a constant-temperature room or thermostat. Run 50 mL of toluene into the 200-mL volumetric flask, using a buret or pipet calibrated to deliver 50 mL of toluene at the chosen temperature (preferably 25"C). Fill the volumetric flask to slightly below the calibration line with n-beptane, insert the ground-glass stopper of the volumetric flask, and mix carefully by repeatedly inverting the flask. Allow to stand for a few

minutes; then bring to the 200-mL calibration mark with heptane and again carefullymix.

9. Calculation 9. l Calculate the kauri-butanol value, V, as follows:

7. Standardization

V = [65(C-

7.1 Weigh out 20 ± 0.10 g of kauri-butanol solution in a 250-mL Erlenmeyer flask and place in the water bath at 25"C. Titrate with the standard toluene into the flask, with constant swirling, while maintaining the mixture in the flask at 25 ± I°C. Gradually reduce the successive amounts of toluene added as the end point is approached. The end point is reached when the sharp outlines of 10-point print placed directly beneath the water bath and observed through the liquid are obscured or blurred, but not to the point where the

B)/(A

-

B)] + 40

where: A - - t o l u e n e required to titrate 20 g of kauri-butanol solution (7.2), mL, B = heptane-toluene blend required to titrate 20 g of kauri-butanol solution (7.3), mL, and C = solvent under test required to titrate 20 g of kauributanol solution (Section 8), mL. 9.2 If the buret is maintained at a temperature other than 25 + l'C, correct the volume of solvent used, S, in millilitres, to standard temperature as follows:

p r i n t becomes illegible. Check the temperature i n the flask

immediately after the end point has been reached, and if over 260C or under 24°C, repeat the titration. 7.2 The volume of toluene used, in millilitres, represents the actual titer for the particular kauri-butanol solution at hand. This value should lie reasonably close to 105 mL, but not over 110 nor under 100 mL. If these limits are exceeded, adjust the concentration of the kauri-butanol solution to bring the total volume of toluene within them. Designate the final value using toluene as A. 7.3 Weigh out 20 ± 0.10 g of the kauri-butanol solution (adjusted as described in 7.2) in a 250-mL Erlenmeyer flask and place in the water bath. Titrate with the heptane-toluene blend in the same manner as described in 7.1. Designate the volume, in millilitres, of the blend used in this titration as B. NOTE 3--If the composition of the blend is known to differ from 25 + 1.0 % toluene, but is within the range from 22 to 28 % toluene, the constant in the blend factor equation will differ from 40.0 by 0.60 units for each 1% toluene. For example, at 28 % toluene, the constant is 41.8 instead of 40.0. NOTE 4--Freshly prepared kauri-butanol solution may change in standardization from day to day. It is, therefore,desirable to permit the solution to age before initial standardization and, in any case, the standardizationshould be recheckedon successivedays until the toluene factor and blend factor remain constant.

S = C(25 - T) x 0.0009

where: C = solvent used in the titration, m L , and T = temperature of the solvent in the buret, "C. 10. Precision and Bias

10.1 The following criteria should be used for judging the acceptability of the results in the range from 30 to 90 at the 95 % confidence level. 10.1.1 RepeatabilitymTwo results, each the mean of duplicates, obtained by the same operator on different days should be considered suspect if they differ by more than 0.01 K - 0.1, where K = mean kauri-butanol value. 10.1.2 Reproducibility---Two results, each the mean of duplicates, obtained by two laboratories should not be considered suspect unless they differ by more than 0.03 K + 1.0 where K = mean kauri-butanol value. 10.2 Bias--Test bias can result if the kauri-butanol solution is not carefully standardized and adjusted (see 7.2 and 7.3). The test method has no definitive bias statement because the value of the test result is defined only in terms of the test method.

8. Procedure 8.1 Weigh 20 +- 0.10 g of the adjusted kauri-butanol solution into a 250-mL Erlenmeyer flask. Place the flask in

11. Keywords I I.I kauri-butanol value; hydrocarbon solvents

The American Society for Testing and Materials takes no position respecting the validity of any patent rights aeserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own respon$1bility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and ff not revised, either respproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Hesdquartere. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend, ff you feel that your oomments have not r ~ e d a fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103.

201

(~l~ Designation:D 1142-95 Standard Test Method for Water Vapor Content of Gaseous Fuels by Measurement of Dew-Point Temperature This standard is issued under the fixed designation D 1142; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (~) indicates an editorial change since the last revision or reapproval.

This standard has been approvedJbr use by agencte~"of the Department of De[ense. Consult the DoD lnd~;~"of Spec~]~cations and Standards.[br the spect]~cyear ¢~issue which has been adopted by the Department of Defense.

1. Scope 1.1 This test method covers the determination of the water vapor content of gaseous fuels by measurement of the dew-point temperature and the calculation therefrom of the water vapor content. NOTE l - - S o m e gaseous fuels contain vapors of hydrocarbons or

other components that easily condense into liquid and sometimes interfere with or mask the water dew point. When this occurs, it is sometimes very helpful to supplement the apparatus in Fig. 1 with an optical attachment 2 that uniformly illuminates the dew-point mirror and also magnifies the condensate on the mirror. With this attachment it is possible, in some cases, to observe separate condensation points of water vapor, hydrocarbons, and glycolamines as well as ice points. However, if the dew point of the condensable hydrocarbons is higher than the water vapor dew point, when such hydrocarbons are present in large amounts, they may flood the mirror and obscure or wash off the water dew point. Best results in distinguishing multiple component dew points are obtained when they are not too closely spaced. NOTE2--Condensation of water vapor on the dew-point mirror may appear as liquid water at temperatures as low as 0 to -10*F (-18 to -23"C). At lower temperatures an ice point rather than a water dew point likely will be observed. The minimum dew point of any vapor that can be observed is limited by the mechanical parts of the equipment. Mirror temperatures as low as -150*F (-100*C) have been measured, using liquid nitrogen as the coolant with a thermocouple attached to the mirror, instead of a thermometer well. 1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

2. Terminology 2.1 Descriptions of Terms Specific to This Standard." 2.1.1 saturated water vapor or equilibrium water-vapor contentmthe water vapor concentration in a gas mixture that is in equilibrium with a liquid phase of pure water that is saturated with the gas mixture. When a gas containing water vapor is at the water dew-point temperature, it is said to be saturated at the existing pressure. 2.1.2 specific volume--ofa gaseous fuel, the volume of the gas in cubic feet per pound. J This test method is under the jurisdiction of ASTM Committee D-3 on Gaseous Fuels, and is the direct responsibility of Subcommittee D03.05 on Determination of Special Constituents of Gaseous Fuels. Current edition approved Feb. 15, 1995. Published April 1995. Originally published as D 1142 - 50. Last previous edition D 1142 - 90. 2 Several pieces of apparatus for this purpose are commercially available, Information concerning this apparatus is available from ASTM Headquarters.

2.1.3 water dew-point temperature--of a gaseous fitel, the temperature at which the gas is saturated with water vapor at the existing pressure.

3. Significance and Use 3.1 Generally, contracts governing the pipeline transmission of natural gas contain specifications limiting the maxi m u m concentration of water vapor allowed. Excess water vapor can cause corrosive conditions, degrading pipelines and equipment. It can also condense and freeze or form methane hydrates causing blockages. Water-vapor content also affects the heating value of natural gas, thus influencing the quality of the gas. This test method permits the determination of water content of natural gas. 4. Apparatus 4.1 Any properly constructed dew-point apparatus may be used that satisfies the basic requirements that means must be provided: 4.1.1 To permit a controlled flow of gas to enter and leave the apparatus while the apparatus is at a temperature at least 3*F above the dew-point of the gas. 4.1.2 To cool and control the cooling rate of a portion (preferably a small portion) of the apparatus, with which the flowing gas comes in contact, to a temperature low enough to cause vapor to condense from the gas. 4.1.3 To observe the deposition of dew on the cold portion of the apparatus. 4.1.4 To measure the temperature of the cold portion on the apparatus on which the dew is deposited, and 4.1.5 To measure the pressure of the gas within the apparatus or the deviation from the known existing barometric pressure. 4.1.6 The apparatus should be constructed so that the "cold spot," that is, the cold portion of the apparatus on which dew is deposited, is protected from all gases other than the gas under test. The apparatus may or may not be designed for use under pressure. 4.2 The Bureau of Mines type of dew-point apparatus 3 shown in Fig. 1 fulfills the requirements specified in 4.1. Within the range of conditions in Section 1, this apparatus is satisfactory for determining the dew point of gaseous fuels. Briefly, this apparatus consists of a metal chamber into and Deaton, W. M., and Frost, E. M., Jr., "Bureau of Mines Apparatus for Determining the Dew Point of Gases Under Pressure." Bureau ~fMines Report n.[ Invt:vtigation 3399, May 1938.

202

~) D 1142

D

FIG. 1

d

Bureau of Mines Dew-Point Apparatus

mirror is thus maintained at a slightly lower temperature than the outer portion, with the result that the dew first appears on the central portion of the mirror and its detection is aided materially by the contrast afforded. The arrangement for measuring the temperature of the target mirror, C, also should be noted. The temperature is read with a thermometer or RTD, K, inserted in the cooling rod, F, so that the bulb of the temperature measuring device is entirely within the thermometer well in fitting, I. The stud to which the stainless steel mirror is silver-soldered is a part of the base of the thermometer well, and as there is no metallic contact between the thermometer well and the cooling tube, other than through its base, the thermometer or RTD indicates the temperature of the mirror rather than some compromise temperature influenced by the temperature gradient along the cooling tube as would be the case if this type of construction were not used. The RTD will include suitable electronics and display. 4.2.2 Tests with the Bureau of Mines type of dew-point apparatus are reported 3 to permit a determination with a precision (reproducibility) of +0.2*F (+0. l'C) and with an accuracy of +0.2*F (-.+0.1*C) when the dew-point temperatures range from room temperature to a temperature of 32"F (0*C). It is estimated that water dew points may be determined with an accuracy of +0.5*F (0.3"C) when they are below 32°F (0*C) and not lower than 0*F ( - 17.8*C), provided ice crystals do not form during the determination.

out of which the test gas is permitted to flow through control valves A and D. Gas entering the apparatus through valve A is deflected by nozzle B towards the cold portion of the apparatus, C. The gas flows across the face of C and out of the apparatus through valve D. Part C is a highly polished stainless steel "target mirror," cooled by means of a copper cooling rod, F. The mirror, C, is silver-soldered to a nib on the copper thermometer well fitting,/, which is soft-soldered to the cooling rod, F. The thermometer well is integral with the fitting, L Cooling of rod F is accomplished by vaporizing a refrigerant such as liquid butane, propane, carbon dioxide, or some other liquefied gas in the chiller, G. The refrigerant is throttled into the chiller through valve H and passes out at J. The chiller body is made of copper and has brass headers on either end. The lower header is connected with the upper header by numerous small holes drilled in the copper body through which the vaporized refrigerant passes. The chiller is attached to the cooling rod, F, by means of a taper joint. The temperature of the target mirror, C, is indicated by a calibrated mercury-in-glass thermometer, K, whose bulb fits snugly into the thermometer well. Observation of the dew deposit is made through the pressure-resisting transparent window, E. 4.2.1 It will be noted that only the central portion of the stainless steel target mirror, C, is thermally bonded to the fitting,/, through which C is cooled. Since stainless steel is a relatively poor thermal conductor, the central portion of the

203

~

D 1142

5. Procedure

5.1 General Considerations--Take the specimen so as to be representative o f the gas at the source. Do not take at a point where isolation would permit condensate to collect or would otherwise allow a vapor content to exist that is not in equilibrium with the main stream or supply o f gas, such as the sorption or desorption o f vapors from the sampling line or from deposits therein. The temperature o f the pipelines leading the specimen directly from the gas source to the dew-point apparatus, and also the temperature o f the apparatus, shall be at least 3*F (1.7"C) higher than the observed dew point. The determination may be made at any pressure, but the gas pressure within the dew-point apparatus must be known with an accuracy appropriate to the accuracy requirements of the test. T h e pressure may be read on a calibrated bourdon-type pressure gage; for very low pressures or more accurate measurements, a mercury-filled m a n o m e t e r or a dead-weight gage should be used. 5.2 Detailed Procedure for Operation of Bureau of Mines Dew-Point Apparatus--Introduce the gas specimen through valve A (Fig. 1), opening this valve wide if the test is to be made under full source pressure (Note 3), and controlling the flow by the small outlet valve, D. The rate o f flow is not critical but should not be so great that there is a measurable or objectionable drop in pressure through the connecting lines and dew-point apparatus. A flow o f 0.05 to 0.5 ft3/min (1.4 to 14 l/min) (measured at atmospheric pressure) usually will be satisfactory. With liquefied refrigerant gas piped to the chiller throttle valve, H, "crack" the valve momentarily, allowing the refrigerant to vaporize in the chiller to produce suitable lowering in temperature of the chiller tube, F, and target mirror, C, as indicated by the thermometer, K. The rate o f cooling m a y be as rapid as desired in making a preliminary test. After estimating the dew-point temperature, either by a preliminary test or from other knowledge, control the cooling or warming rate so that it does not exceed l*F/min (.5*C/min) when this temperature is approached. For accurate results, the cooling and warming rates should approximate isothermal conditions as nearly as possible. The most satisfactory method is to cool or warm the target mirror stepwise. Steps o f about 0.2*F (0.1*C) allow equilibrium conditions to be approached closely and favor an accurate determination. W h e n dew has been deposited, allow the target mirror to warm up at a rate comparable to the recommended rate o f cooling. The normal warming rate usually will be faster than desired. To reduce the rate, "crack" valve H momentarily at intervals to supply cooling to the cooling tube, F. Repeat the cooling and warming cycles several times. The arithmetic average o f the temperatures at which dew is observed to appear and disappear is considered to be the observed dew point.

temperatures over a suitable range of pressures for the gas being tested is available, the water-vapor content may be read directly, using the observed water dew-point temperature and the pressure at which the determination was made. 6.2 If such a chart is not available, the water-vapor content o f the gas may be calculated from the water dew-point temperature and the pressure at which it was determined (see Note 3), as follows: W = w × 106 × (Pb/P × (T/Tb)) where: W = lb o f water/million ft 3 of gaseous mixture at pressure Pb and temperature Tb, w = weight of saturated water vapor, lb/ft 3, at the water dew-point temperature, that is, the reciprocal of the specific volume o f saturated vapor (see Table 1), Pb = pressure-base of gas measurement, psia, P = pressure at which the water dew point of gas was determined, psia, t = observed water dew-point temperature, *F, T = Rankine (absolute Fahrenheit scale) water dew point, t + 460, at pressure P, and T b = base temperature o f gas measurement, t b + 460. NOTI~ 4--Example 1: Given: Water dew point = 37"F at 15.0 psia pressure. What is the water-vapor content million ft3 of gas (gas measurement base of 60*F and 14.7 psia pressure)? From Table 1 the specific volume of saturated water at 37"F is 2731.9 fta/Ib, from which: w = (1/2731.9) = 0.000 3660 lb/ft, 3 and

W= 0.000 3660 x 106 x (14.7/15.0) × [(460 + 37)/(460 + 60)] = 342.8 Ib/million ft3

Example 2: Given: Water dew point = 5*F at 14.4 psia. From Table 1, the specific volume of saturated water vapor with respect to ice at 5*F is 11 550 ft3/lb from which Wice.5v = 0.000 086 6, but the observed water dew point was in equilibrium with subcooled liquid water at 5*F. From Table I (data from International Critical Tables4), the vapor pressures of subcooled liquid water and of ice at 5*F (-15"C) are 1.436 mm and 1.241 mm Hg, respectively. Since the vapor pressure of subcooled liquid water is greater than ice at the same temperature, the weight per cubic foot of water vapor in equilibrium with liquid water will be proportionately larger than the value calculated from the specific volume read from the table, which is for equilibrium with ice. Hence, Whq.. 5F

= Wi~ 5F x (1.436/1.241) = 0.000086 6 X 1.157 -- 0.000 100 2 and W = 0.000 100 2 X 106 X (14.7/14.4) x [(460 + 5)/[460 + 60)] = 91.5 lb/million ft3

Note 3--If the water-vapor content is to be calculated as described in 6.2, the gas specimen should be throttled at the inlet valve, A, to a pressure within the apparatus approximately equal to atmospheric pressure. The outlet valve may be left wide open or restricted, as desired. The pressure existing within the apparatus must, however, be known to the required accuracy.

6.3 A correlation o f the available data on the equilibrium water content of natural gases has been reported by

6. Calculation 6.1 If an acceptable chart showing the variation o f water-vapor content with saturation or water dew-point

4 InternationalCritical Tables, Vol III, National Research Council. McGrawHill BookCo., Inc., New York, NY, pp. 210-21I. 1928. 204

tIN

D 1142

I00~\\\N~.

Bukacek. 5 This correlation is believed to be accurate enough for the requirements of the gaseous fuels industry, except for unusual situations where the dew point is measured at conditions close to the critical temperature of the gas. The correlation is a modified form of Raoult's law having the following form:

~o ~ ~ - - - + - ~ - - l - - w l - - ~ -~~ ~,\\\\\\\x,~\\\-~k ~\\\\\\\~',.\\\I .~ '

' I

I~_

~-I- . . . . . .

L I I] J

I

I

W = (A/P) + B

where: W = water-vapor content, lb/million ft 3, P = total pressure, psia, A = a constant proportional to the vapor pressure of water, and B = a constant depending on temperature and gas composition.

~ K\\\\\\N\\"x2x\~"

4

NOTE 5--Values of B were computed from available data on methane, methane-ethane mixtures, and natural gases.

~

,xa~N',K", K",kNN",,,~x~",~

~

2

6.3.1 Table 2 lists values of the constants A and B for natural gases in the temperature range from - 4 0 to 460"F ( - 4 0 to 238"C). 6.3.2 Table 3 lists values of water-vapor content from - 4 0 to 250"F (-40* to 121"C) and from 14.7 to 5000 psia (101 to 34475 kPa), covering the range of most natural gas processing applications. 6.3.3 A convenient graphical representation of the data in Table 3 is illustrated in Fig. 2. 6 The moisture content values given can be corrected to base conditions other than 14.7 psia (101 kPa) and 60*F (15.5"C) by the same equations given in Table 2.

o o

~

o o

o o o oooo o o o oooo

o o

o o

Pressure, psio

FIG. 2

Equilibrium Water Vapor Content of Natural Gases

7. Precision and Bias 7.1 No precision data is available for this test method, however, the Committee is interested in conducting an interlaboratory test program and encourages interested parties to contact the Staff Manager, Committee D-3, ASTM Headquarters.

Bukacek, R. F., "Equfl;brium Moisture Content of Natural Gases," Research Bulletin 8, Inst*tute of Gas Technology, 1955, Reports work sponsored by the Pipeline Research Committee of the American Gas Association. 6 Complete sets of these charts covering the entire range of pressures and temperatures of Table 3 may be purchased from the Institute of Gas Technology, 3424 S. State St., Chicago, IL 60616.

8. Keywords 8. l gaseous fuels; natural gas

205

~) TABLE 1

D 1142

Vapor Pressures and Specific Volumes of Saturated Water Vapor st V a d o u s Temperatures A

mm Hg

psia

mm Hg

psia

Specific Volume of Saturated Water Vapor ftS/Ib

1.139

0.022 02

0.958

0,018 52

14 810

1.195 1,251 1.310 1.373 1,436

0,023 0,024 0.025 0,026 0.027

11 19 33 55 77

1.010 1.063 1.120 1,180 1.241

0.019 0.020 0.021 0,022 0.024

53 56 66 82 00

14 13 12 12 11

080 400 750 140 550

51 52 53 54 55

0.184 0.191 0.199 0.206 0.214

85 82 01 44 11

1 1 1 1 1

644.2 587,6 533.2 480.9 430.6

6 7 8 9 10

1.505 1.573 1,647 1,723 1,807

0.029 0.030 0.031 0.033 0,034

10 42 85 32 94

1,308 1.374 1.446 1.521 1,599

0.025 0.026 0.027 0.029 0,030

29 57 96 41 92

11 10 9 9 9

000 480 979 507 060

56 57 58 59 60

0.222 0,230 0.238 0.247 0.256

03 21 65 36 35

1 1 1 1 1

382.2 335.6 290.9 247.8 206,3

11 12 13 14 15

1.883 1.970 2.057 2.149 2.247

0.036 0.038 0,039 0.041 0.043

41 09 78 56 45

1.681 1.767 1.856 1,950 2.050

0.032 0.034 0,035 0.037 0,039

51 17 89 71 64

8 8 7 7 7

636 234 851 489 144

61 62 63 64 65

0,265 0,275 0.285 0,295 0.305

62 19 06 24 73

1 166.4

16 17 18 19 20

2.345 2.450 2,557 2.607 2.785

0.045 0.047 0.049 0.051 0,053

35 37 44 63 85

2.151 2.260 2.373 2.489 2.610

0,041 0,043 0.045 0.048 0.050

59 70 89 13 47

6 6 6 5 5

817 505 210 929 662

66 67 68 69 70

0.316 0,327 0,339 0.351 0.363

55 70 20 05 26

988.03 956.19 925,51 895.94 867.44

21 22 23 24 25

2.907 3,032 3.163 3.299 3.433

0.056 0.058 0.061 0.063 0.066

21 63 16 79 38

2.740 2.872 3.013 3.160 3.310

0.052 0.055 0.058 0.061 0.064

98 54 26 10 01

5 5 4 4 4

408 166 936 717 509

71 72 73 74 75

0.375 0.388 0.402 0.415 0.430

84 79 14 88 04

839.97 813.48 787.94 763.31 739.55

26 27 28 29 30

3.585 3.735 3.893 4,054 4,224

0.069 0,072 0.075 0.078 0.081

32 22 28 39 68

3.471 3.636 3.810 3.989 4.178

0,067 0.070 0.073 0,077 0.080

12 31 67 14 79

4 4 3 3 3

311 122 943 771 608

76 77 78 79 80

0.444 0,459 0.475 0,490 0.507

61 61 05 94 29

716.62 694.51 673,16 652.56 632.68

31 32 33 34 35

4.397 4.579

0,085 0,088 0.092 0.096 0,099

02 66 30 07 98

4.373 4.579 .., ... ...

0.084 56 0.088 54

3 3 3 3 2

453 301,9 178.0 059.2 945.5

81 82 83 84 85

0.524 0.541 0.559 0.577 0.596

11 42 22 53 36

613.48 594.95 577.05 559.76 543.07

36 37 38 39 40

0.104 0,108 0.112 0.117 0.121

04 23 58 08 73

2 2 2 2 2

836.4 731.9 631.7 535.7 443.5

86 87 88 89 90

0,615 0.635 0.656 0.677 0.698

73 63 09 13 74

526.94 511.35 496.29 481.73 467.66

41 42 43 44 45

0,126 0,131 0.136 0,142 0.147

55 54 70 04 56

2 2 2 2 2

355,1 270,3 188.9 110.8 035.8

91 92 93 94 95

0.720 0.743 0.767 0.791 0.816

95 77 22 30 04

454.06 440.91 428.19 415.89 403.99

46 47 48 49 50

0.153 0.159 0.165 0.171 0.178

28 18 28 59 12

1 1 1 1 1

963.8 894.6 828.2 764.4 703.1

96 97 98 99 100

0.841 0.867 0.894 0,921 0,950

44 53 31 80 03

392.48 381.35 370.58 360.15 350.06

Temperature, oF

Vapor Pressure of Liquid Water

Vapor Pressure of Ice

Temperature, °F

Vapor Pressure of Liquid Water,

SpecificVolume of Saturated Water

psia

Vapor, ftS/Ib

1 1 1 1

128.0 091.0 055.4 021.1

'* The values for vapor pressure, from 0 to 32 ° F, were calculated from data in the Intemational Critical Tables.4 All other values were taken from Harr, Gallagher, and Kell, "NBS/NRC Steam Tables," National Standard Reference Data System, 1984, p. 9. Data on specific volumes of saturated water vapor from 0 to 32°F were obtained from Goff, J. A., and Gratch, S., "Low-Pressure Properties of Water from -160 to 212°F, '' Heating, Piping, and Air Conditioning, Vol 18, No. 2, Feb. 1946, pp. 125-136.

206

t~ D 1142 TABLE 2 Values of Constants A and B (Base Conditions = 14.7 psia, 60°F) Temperature, °F

A

B

Temperature, °F

A

B

Temperature, °F

A

B

-40 -38 -36 -34 -32 -30 -28 -26 -24 -22

131 147 165 164 206 230 256 285 317 352

0.22 0.24 0.26 0.28 0.30 0.33 0.36 0.39 0.42 0.45

70 72 74 76 78 80 82 84 86 88

17 18 19 21 22 24 25 27 29 31

200 500 700 100 500 100 700 400 200 100

7.17 7.85 8.25 8.67 8,11 9.57 10.0 10.5 11.1 11.6

180 182 184 186 188 190 192 194 196 198

357 372 390 407 425 443 463 483 504 525

000 000 000 000 000 000 000 000 000 000

74.8 77.2 79.9 82.7 85.8 88.4 91.4 94.8 97.7 101

-20 -18 -16 -14 -12 -10 -8 -6 -4 -2

390 434 479 530 586 648 714 786 866 950

0.48 0.52 0.56 0.60 0.64 0.69 0.74 0.79 0.85 0.91

90 92 94 96 98 100 102 104 106 108

33 35 37 39 42 45 47 50 53 57

200 300 500 900 400 100 900 600 900 100

12.2 12.7 13.3 14.0 14.6 15.3 16.0 16.7 17.5 18.3

200 202 204 206 208 210 212 214 216 218

547 570 594 619 644 671 698 725 754 785

000 000 000 000 000 000 000 000 000 000

104 108 111 115 119 122 126 130 134 139

000 000 000 000 000 000 000 000 000 000

143 148 152 157 162 166 171 177 182 167

0 2 4 6 8 10 12 14 16 18

1 1 1 1 1 1 1 1 2 2

050 150 260 380 510 650 810 970 150 350

0.97 1.04 1.11 1.19 1.27 1.35 1.44 1.54 1.64 1.74

110 112 114 116 118 120 122 124 126 128

60 64 67 71 76 80 84 89 94 100

500 100 900 800 000 400 900 700 700 000

19.1 20.0 20.9 21.8 22.7 23.7 24.7 25.8 26.9 28.0

220 222 224 226 228 230 232 234 236 238

1 1 1 1

816 848 881 915 950 987 020 060 100 140

20 22 24 26 28 30 32 34 36 38

2 2 3 3 3 3 4 4 4 5

560 780 030 290 570 880 210 560 940 350

1.85 1.97 2.09 2.22 2.36 2.50 2.65 2.81 2.98 3.16

130 132 134 136 138 140 142 t44 146 148

106 111 117 124 130 137 144 152 160 168

000 000 000 000 000 000 000 000 000 000

29.1 30.3 31.6 32.9 34.2 35.6 37.0 38.5 40.0 41.6

240 242 244 246 246 250 252 254 256 258

1 1 1 1 1 1 1 1 1 1

190 230 270 320 370 420 470 520 570 630

000 000 000 000 000 000 000 000 000 000

192 198 204 210 216 222 229 235 242 248

40 42 44 46 48 50 52 54 56 58

5 6 6 7 7 8 9 9 10 11

780 240 740 280 850 460 110 800 500 300

3.34 3.54 3.74 3.96 4.18 4.42 4.66 4.92 5.19 5.48

150 152 154 156 156 160 162 164 166 168

177 186 195 205 215 225 236 248 259 272

000 000 000 000 000 000 000 000 000 000

43.2 44.9 46.6 48.4 50.2 52.1 54.1 56.1 58.2 60.3

260 280 300 320 340 360 380 400 420 440

1 2 3 4 5 7 9 11 14 18

680 340 180 260 610 270 300 700 700 100

000 000 000 000 000 000 000 000 000 000

255 333 430 548 692 869 1090 1360 1700 2130

60 62 64 66 66

12 13 14 15 16

200 100 000 000 100

5.77 6.08 6.41 6.74 7.10

170 172 174 176 178

285 298 312 326 341

000 000 000 000 000

62.5 64.8 67.1 69.5 72.0

460

22 200 000

NOTE--To correct A and B to other base conditions, multiply each by: (Pb/14.7) x [519.6/(to + 459.6)] x (0.998/2'o) where: Pb = absolute base pressure, psia t~ = base temperature, °F and Zb = compressibility factor under base conditions.

207

~ TABLE 3

D 1142

Equilibrium Water Vapor Contents of Natural Gases Above the Critical Temperatures (Ib/mdlion ft3 where P,, = 14.7 psia, tb = 60TM)

Tempera-

Total Pressure, psia

ture, TM

14.7

100

-40 -38 -36 -34 -32

9.1 10.2 11.5 12.8 14.4

-30 -26 -26 -24 -22

200

300

400

500

600

700

800

900

1.5 1.7 1.9 2.1 2.4

0.88 0.98 1.1 1.2 1.3

0.66 0.73 0.80 0.90 0.99

0.55 0.61 0.68 0.74 0.82

0.49 0.54 0.59 0.65 0.72

0.44 0.49 0.54 0.59 0.65

0.41 0.45 0.50 0.55 0.60

0.39 0.43 0.47 0.51 0.57

0.37 0.41 0.45 0.49 0.54

0.36 0.39 0.43 0.47 0.51

16.0 17.8 19.8 22.0 24.4

2.6 2.9 3.2 3.6 4,0

1.5 1.6 1.8 2.0 2.2

1.1 1.2 1.3 1.5 1.6

0.91 1.0 1.1 1.2 1.3

0.79 0.87 0.96 1.1 1.2

0.72 0.79 0.66 0.95 1.0

0.66 0.72 0.79 0.~ 0.95

0.62 0,68 0.74 0.81 0.89

0.59 0.64 0.70 0.77 0.84

0.56 0.61 0.67 0.73 0.80

-20 -18 -16 -14 -12

27.0 30.0 33.1 36.7 40.5

4.4 4.9 5.4 5.9 6.5

2.4 2.7 3.0 3.3 3.6

1.8 2.0 2.2 2.4 2.6

1.5 1.6 1.8 1.9 2.1

1.3 1.4 1.5 1.7 1.8

1.1 1.2 1.4 1.5 1.6

1.0 1.1 1.2 1.4 1.5

0.97 1.1 1.2 1.3 1.4

0.92 1.0 1.1 1.2 1.3

0.87 0.95 1.0 1.1 1.2

-10 -8 -6 -4 -2

44.8 49.3 54.6 59.8 65.7

7.2 7.9 8.7 9.5 10.4

4.0 4.3 4.7 5.2 5.7

2.9 3,1 3.4 3.7 4.1

2.3 2.5 2.8 3.0 3.3

2.0 2.2 2.4 2.6 2.6

1.6 1.9 2.1 2.3 2.5

1.6 1.8 1.9 2.1 2.3

1.5 1.6 1.8 1.9 2.1

1.4 1.5 1.7 1.8 2.0

1.3 1.5 1.6 1.7 1.9

0 2 4 6 8

72.1 79.1 86.8 95.1 104

11.4 12.5 13.7 15.0 16.4

6.2 6.8 7.4 8,1 8.8

4.5 4.9 5.3 5.8 6.3

3.6 3.9 4.3 4.6 5.1

3.1 33 3.6 4,0 4.3

2.7 3.0 3.2 3.6 3.8

2.5 2.7 2,9 3.2 3.4

2.3 2.5 2.7 2.9 3.2

2.1 2.3 2.5 2.7 3.0

2.0 2.2 2.4 2.6 2.8

10 12 14 16 18

114 124 136 148 161

17.9 19.5 21.3 23.2 25.2

9.6 10.5 11.4 12.4 13.5

6.9 7.5 8.1 8.6 9.6

5.5 6.0 6.5 7.0 7.6

4.7 5.1 5.5 5.9 6.4

4.1 4.5 4.8 5.2 6.7

3.7 4.0 4.5 4.7 5.1

3.4 3.7 4.0 4.3 4.7

3.2 3.5 3.7 4.0 4.4

3.0 3.3 3.5 3.8 4.1

20 22 24 26 28

176 191 208 226 246

27.4 29.8 32.4 35.1 38,1

14.6 15.9 17.2 18.7 20.2

10,4 11.3 12.2 13.2 14.3

8.2 8.9 9.7 10,5 11.3

7.0 7.5 8,2 8.8 9.5

6.1 6.6 7.2 7.7 8.3

5.5 5.9 6.4 6,9 7.5

5.1 5,5 5.9 6.3 6.8

4.7 5.1 5.5 5.9 6.3

4.4 4.8 5.1 5.5 5.9

30 32 34 36 38

276 289 313 339 367

41.3 44.7 46.4 52.4 56.6

21.9 23.7 25.6 27.7 29.9

15.4 16.7 18.0 19.4 20.1

12.2 13.2 14.2 15.3 16.5

10.3 11.1 11.9 12.9 13.9

9.0 9.7 10.4 11.2 12.1

8.0 8.7 9.3 10.0 10.8

7.4 7.9 8.5 9.2 9.8

6.8 7.3 7.9 8,5 9.1

6.4 6.9 7.4 7.9 8.5

40 42 44 46 48

396 428 462 499 538

61.1 66.0 71.2 76.7 82.6

32.2 34.6 37.5 40.3 43.4

22.6 24.4 26.2 28,2 30.3

17,8 19.2 20.6 22.2 23.8

14.9 16.0 17.2 18.5 19.9

13.0 13.9 15.0 16.1 17.3

11.6 12.5 13.4 14.4 15.4

10.6 11.3 12.2 13.1 14.0

9.8 10.5 11.2 12.0 12.9

9.1 9.8 10.5 11.2 12.0

208

1000

(@) D 1142 TABLE 3

Equilibrium Water Vapor Contents of Natural G ases Above the Cdtical

Tempera-

Temperatures--Continued

Total Pressure, psia

ture, °F

14.7

100

300

400

500

600

700

800

900

50 52 54 56 58

580 624 672 721 776

89.0 95.7 103 111 119

46.7 50.2 54,0 57.9 62.1

200

32,6 35.0 37.6 40.3 43.2

25.6 27.4 29,4 31,5 33.8

21.3 22.9 24.5 26.7 28.1

18.5 19.8 21.3 22.8 24.4

16.5 17.7 18.9 20,3 21.7

15.0 16.1 17.2 18.3 19.6

13.8 14.8 15.8 16.9 18.0

12.9 13.8 14.7 15.7 16.8

60 62 64 66 68

834 895 960 1 030 1 100

128 137 147 157 168

66.6 71.4 76.5 81.8 87.6

46.3 49.6 53.1 56,8 60.7

36.2 38,7 41.4 44.3 47.3

30.1 32.2 34.4 36.8 39.3

26.1 27.9 29.8 31.8 33.9

23.2 24.7 26.4 28.2 30.1

21.0 22,4 23.9 25.5 27.2

19.3 20,6 22,0 23.4 25.0

17.9 19.1 20.4 21.8 23.2

70 72 74 76 78

1 1 1 1 1

180 260 350 440 540

180 192 206 220 235

93.7 100 107 114 122

65.0 69.4 74.0 79.0 84.2

50.6 54.0 57.6 61.4 65,5

42.0 44.8 47.7 50.9 54.2

36.2 38.6 41.1 43.8 46.7

32.1 34.2 36.4 38.8 41.3

29.0 30.9 32.9 35.0 37,3

26.6 28.4 30.2 32.1 34.2

24.7 26.3 28.0 29.8 31,7

80 82 84 86 88

1 1 1 2 2

650 760 870 000 130

250 267 285 303 323

130 138 148 157 167

89.8 95.6 102 108 115

69.7 74.2 79.0 84.1 89.4

57.5 61.4 65.3 69.5 73.8

49.7 52.8 56.2 59.7 63.5

44.0 46.7 49.7 52.8 56.1

39,7 42.1 44.8 47.6 50.5

36.3 38.6 41.0 43.5 46.2

33.6 36.7 37.9 40.3 42.7

90 92 94 96 98

2 2 2 2 2

270 410 570 730 900

344 366 389 413 439

178 189 201 214 227

123 130 138 147 156

95.0 101 107 114 121

78.5 83.3 88.4 93.8 99.5

67.4 71.5 75.9 80.5 85.3

59.5 63.1 67.0 71.0 75.2

53.6 56.8 60.3 63.9 67.6

49.0 51.9 55.0 58.3 61.8

45.3 48.0 50.9 53.9 57.0

100 102 104 106 108

3 3 3 3 3

080 270 470 680 900

466 495 525 557 589

241 256 271 287 304

166 176 186 197 209

128 136 144 152 161

105 112 118 125 133

90.4 95.8 101 107 114

79,7 84,4 89.3 94.5 99,9

71.6 75.9 80.2 84.9 89.7

65,4 69,2 73.1 77.4 81.7

110 112 114 116 118

4 4 4 4 5

130 380 640 910 190

624 661 700 740 783

322 341 360 381 403

221 234 247 261 276

170 180 191 201 213

140 148 157 165 175

120 127 134 142 149

106 112 118 124 131

94.7 100 106 112 118

86.3 91.2 96.2 102 107

120 122 124 126 128

5 5 6 6 6

490 800 130 470 830

828 874 923 974 1030

426 449 474 500 528

292 308 325 343 361

225 237 250 264 278

185 195 205 216 228

158 166 175 185 195

139 146 154 162 171

124 131 138 145 153

113 119 125 132 139

130 132 134 136 138

7 7 7 8 8

240 580 990 470 880

1090 1140 1200 1270 1330

559 585 617 653 684

382 400 422 446 468

294 308 324 343 359

241 252 266 281 294

206 215 227 240 251

181 189 199 210 220

162 169 178 188 197

147 154 162 171 179

140 142 144 146 148

9 9 10 10 11

360 830 400 900 500

1410 1480 1560 1640 1720

721 757 799 840 882

492 517 545 573 602

378 397 419 440 462

310 325 343 360 378

264 277 292 307 322

231 243 256 269 282

207 217 229 240 252

188 197 207 218 229

209

1000

(@) D 1142 TABLE 3

Equilibrium W a t e r V a p o r C o n t e n t s o f Natural G a s e s A b o v e t h e Critical

Temperatures--Continued

Total Pressure, psia Temperature, OF

14.7

100

200

300

400

500

600

700

800

900

100 700 300 000 700

1810 1910 2000 2100 2200

928 975 1020 1070 1130

633 665 697 732 767

486 510 534 581 588

397 417 437 458 480

338 355 372 390 409

296 311 325 341 357

264 277 290 305 319

240 252 263 276 289

160 162 164 166 168

15 400 ... ... ... ...

2300 2410 2540 2650 2780

1180 1230 1300 1350 1420

802 841 883 922 967

615 644 676 706 740

502 526 552 576 604

427 447 469 490 514

374 391 410 428 449

333 349 386 382 400

302 316 332 346 363

170 172 174 176 178

... .., ... ...

2910 3040 3190 3330 3480

1490 1550 1630 1700 1780

1010 1060 1110 1160 1210

775 810 847 885 925

633 661 691 722 754

538 562 587 613 640

470 491 513 535 559

419 437 457 477 498

379 396 414 432 451

180 182 164 186 188

... ... ... ,,. ...

3640 3800 3980 4150 4340

1860 1940 2030 2120 2210

1260 1320 1380 1440 1500

967 1010 1060 1100 1150

789 821 860 897 936

670 697 730 761 794

585 609 637 664 693

521 542 567 591 617

471 491 513 535 558

190 192 194 196 198

... ... ... ... ...

4520 4720 4920 5140 5350

2300 2410 2510 2620 2730

1570 1630 1700 1780 1850

1200 1250 1300 1360 1410

974 1020 1060 1110 1150

827 863 900 938 976

721 753 785 818 851

642 670 698 728 757

581 606 631 658 684

200 202 204 206 208

,,. ... ... ... .,.

5570 5810 6050 6310 • ..

2840 2960 3080 3210 3340

1930 2010 2090 2180 2270

1470 1538 1600 1660 1730

1200 1250 1300 1350 1400

1020 1060 1100 1150 1190

885 922 960 999 1040

788 821 854 689 924

712 741 771 803 835

210 212 214 216 218

... ... ... ... ..,

3480 3620 3760 3910 4060

2360 2450 2550 2650 2760

1800 1870 1950 2020 2100

1460 1520 1580 1640 1710

1240 1290 1340 1390 1450

1080 1120 1160 1210 1260

961 999 1040 1080 1120

868 902 937 973 1010

220 222 224 226 228

.., ... ... ... ...

4220 4390 4560 4730 4910

2860 2980 3090 3200 3330

2180 2270 2350 2440 2540

1780 1840 1910 1990 2060

1500 1560 1620 1680 1750

1310 1360 1410 1460 1520

1160 1200 1250 1300 1350

1050 1090 1130 1170 1220

5100

3460

2630

2140

1810

1580

1400

1260

4160

3170

2570

2180

1890

1680

1510

3770

3060

2590

2250

2000

1800

150 152 154 156 158

12 12 13 14 14

230 240

, ° .

. ° °

, ° .

250

210

(~) TABLE 3

D 1142

Equilibrium Water Vapor Contents of Natural G ases Above the Critical

Tempera-

Temperatures--Continued

Total Pressure, psia

ture,°F

1000

1500

2000

2500

3000

3500

4000

4500

5000

100 102 104 106 108

60.4 63.9 67.5 71.4 75,4

45.4 47.9 50.6 53.4 56.4

37.9 40.0 42.1 44.5 46.9

33,3 35.5 37.0 39.1 41,1

30.3 32.0 33.6 35.5 37.3

28.2 29.7 31.2 32.9 34.6

26.6 28.0 29.4 31.0 32,6

25.3 26.6 28.0 29.5 31.0

24.3 25.6 26.9 28.3 29.7

110 112 114 116 118

79.6 84.1 88.7 93.6 98.7

59.4 62.7 66.1 69.7 73.4

49.4 52.1 54.8 57.7 60.7

43.3 45.6 48.0 50.5 53.1

39.3 41.4 43.4 45.7 48.0

36.4 38.3 40.2 42.3 44.4

34.2 36.0 37.8 39.8 41.7

32.5 34.2 35.9 37.8 39.6

31.2 32.8 34.4 36.2 37.9

120 122 124 126 128

104 110 116 122 128

77.3 81.3 85.6 89.9 94.7

63.9 67.2 70.7 74,2 78.0

55.9 58.7 61.7 64.7 68.0

50.5 53.0 55.7 58.4 61.3

46.7 49.0 51.4 53.9 56.6

43.8 45.9 48.2 50.5 53.0

41,6 43.6 45,7 47.8 50.2

39.8 41.7 43.7 45.7 48.0

130 132 134 136 138

135 141 149 157 164

99.8 104 110 116 121

82.1 85.8 90.1 94.9 99.2

71.6 74.7 78.4 82.5 86.2

64.4 67.3 70.6 74.2 77.5

59.4 62.0 65.0 68.3 71.3

55.6 58.1 60.9 63,9 66.7

52.6 55.0 57.6 60.3 63.1

50.3 52.5 55.0 57.7 60.2

140 142 144 146 148

173 181 191 200 210

127 133 140 147 154

104 109 115 120 126

90.4 94.6 99.3 104 109

81.3 85.0 89.2 93.0 97.6

74,7 78.1 81.9 85.7 89.6

69.9 73.0 76.5 80,0 83.6

66.0 69.0 72.3 75.6 78.9

63.0 65.8 68.9 72.0 75.6

150 152 154 158 158

220 231 242 253 265

161 169 177 185 194

132 138 144 151 158

114 119 125 130 136

102 107 112 117 122

93.8 98.0 102 107 112

87.5 91.4 95.4 100 104

82.5 86.2 89.9 94.0 98.0

78.6 82.1 85.6 89,4 93.2

160 162 164 166 168

277 290 304 317 332

202 211 221 231 242

165 172 180 188 196

142 149 155 162 169

127 133 139 145 151

116 122 127 132 138

108 113 118 123 128

102 107 111 116 121

97.1 101 106 110 115

170 172 174 176 178

348 363 379 396 413

253 263 275 287 299

205 214 223 233 243

177 184 192 200 208

158 165 171 178 186

144 150 156 163 169

134 139 145 151 157

126 131 136 142 148

120 124 130 135 140

180 182 184 186 188

432 449 470 490 511

313 325 340 354 369

253 263 275 286 298

217 226 236 245 256

194 201 210 218 227

177 184 191 199 207

164 170 177 184 192

154 160 167 173 180

146 152 158 164 171

190 192 194 196 198

531 554 578 602 626

384 400 417 434 451

310 323 336 350 364

266 277 288 299 311

236 246 256 266 276

215 224 233 242 251

199 207 215 224 232

187 194 202 210 218

177 184 191 199 206

211

fl~ D 1142 TABLE 3 Temperature, °F

Equilibrium Water Vapor Contents of Natural G ases A b o v e the Critical T e m p e r a t u r e s - - C o n c l u d e d Total Pressure, psia 1000

1500

2000

2500

3000

3500

4000

4500

5000

200 202 204 206 208

651 678 705 734 763

469 488 507 528 548

378 393 408 425 441

323 336 349 363 377

286 298 309 321 334

260 271 281 292 303

241 251 260 270 280

226 235 243 253 262

213 222 230 238 248

210 212 214 216 218

793 824 856 889 924

569 591 614 637 662

458 475 493 512 532

390 405 420 436 453

346 359 372 386 401

314 325 337 350 363

290 301 312 323 335

271 281 291 302 313

256 266 275 285 296

220 222 224 226 228

959 996 1030 1070 1110

687 713 739 767 795

551 572 593 615 637

469 487 504 523 542

415 431 446 462 479

376 390 404 418 433

347 360 372 386 400

324 336 348 360 373

306 318 328 340 352

230

1150

824

660

561

495

448

413

385

363

240

1380

985

787

668

589

532

490

456

430

250

1640

1170

932

790

695

628

577

538

506

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reepproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration st a meeting of the responsible technical committee, which you may attend, if you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103.

212

Designation: D 1159 - 93

TIIF I N S r I I ~ T f

Designation: 130/92

Standard Test Method for Bromine Numbers of Petroleum Distillates and Commercial Aliphatic Olefins by Electrometric Titration I This standard is issued under the fixed designation D 1159; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsiion (~) indicates an editorial change since the last revision or reapproval.

1. Scope 1.1 This test method 2 covers the determination of the bromine number of the following materials: 1.1.1 Petroleum distillates that are substantially free of material lighter than isebutane and that have 90 % distillation points (by Test Method D 86) under 327"C (626°F). This test method is generally applicable to gasoline (including leaded, unleaded and oxygenated fuels), kerosine, and distillates in the gas oil range that fall in the following limits: 90 % Distillation Point, "C ('F)

Bromine Number, max2

Under 205 (400) 205 to 327 (400 to 626)

175 10

to bromine index is not applicable for these lower values of bromine number. 1.4 The values stated in SI units are to be regarded as the standard. The inch-pound units given in parentheses are for information purposes only. 1.5 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific precautionary statements, see Notes 3 through 1 1.

2. Referenced Documents 2.1 A S T M Standards: D 86 Test Method for Distillation of Petroleum Products 3 D 1193 Specification for Reagent Water 4 D 1492 Test Method for Bromine Index of Aromatic Hydrocarbons by Coulometric Titration 5 D2710 Test Method for Bromine Index of Petroleum Hydrocarbons by Electrometric Titration 6

1.1.2 Commercial olefins that are essentially mixtures of aliphatic mono-olefins and that fall within the range of 95 to 165 bromine number (see Note 1). This test method has been found suitable for such materials as commercial propylene trimer and tetramer, butene dimer, and mixed nonenes, octenes, and heptenes. This test method is not satisfactory for normal alpha-olefins. NOTE l--These limits are imposed since the precision of this test method has been determined only up to or within the range of these bromine numbers. 1.2 The magnitude of the bromine number is an indication of the quantity of bromine-reactive constituents, not an identification of constituents; therefore, its application as a measure of olefinic unsaturation should not be undertaken without the study given in Annex A 1. 1.3 For petroleum hydrocarbon mixtures of bromine number less than 1.0, a more precise measure for brominereactive constituents can be obtained by using Test Method D 2710. If the bromine number is less than 0.5, then Test Method D 2710 or the comparable bromine index methods for industrial aromatic hydrocarbons, Test Method D 1492, must be used in accordance with their respective scopes. The practice of using a factor of 1000 to convert bromine number

3. Terminology 3.1 Description of a Term Specific to This Standard: 3.1.1 bromine numberwthe number of grams of bromine that will react with 100 g of the specimen under the conditions of the test.

4. Summary of Test Method 4.1 A known weight of the specimen dissolved in a specified solvent ( 1,1, I trichloroethane, see 7.11) maintained at 0 to 5°C (32 to 41°F) is titrated with standard bromidebromate solution. The end point is indicated by a sudden change in potential on an electrometric end point titration apparatus due to the presence of free bromine. 5. Significance and Use 5.1 The bromine number is useful as a measure aliphatic unsaturation in petroleum samples. When used conjunction with the calculation procedure described Annex A2, it can be used to estimate the percentage

This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.04.0D on Physical Methods. In the IP, this test method is under the jurisdiction of the Standardization Committee. Current edition approved Aug. 15, 1993. Published October 1993. Originally published as D 1159 - 51 T. Last previous edition D 1159 - 89. 2 See Dubois, H. D., and Skoog, D. A., "Determination of Bromine Addition Numbers," Analytical Chemistry, Vol 20, 1948, pp. 624-7.

3AnnualBookofASTM Standards, Vol05.01. 4AnnualBookofASTM Standards, Vol 11.01. s AnnualBookofASTM Standards, Vo106.03. 6AnnualBookofASTM Standards, Vo105.02.

213

of in in of

4{~ D 1159 olefins in petroleum distillates boiling up to approximately 315"C (600"F). 5.2 The bromine number of commercial aliphatic monoolefins provides supporting evidence of their purity and identity.

6. Apparatus 6.1 Electrometric End Point Titration Apparatus--Any apparatus designed to perform titrations to pre-set end points (see Note 10) may be used in conjunction with a highresistance polarizing current supply capable of maintaining approximately 0.8 V across two platinum electrodes and with a sensitivity such that a voltage change of approximately 50 mV at these electrodes is sufficient to indicate the end point. Other types of commercially available electronic titrimeters, including certain pH meters, have also been found suitable. NOTE 2--Pre-set end point indicated with polarized electrodesprovides a detection technique similar to the dead stop technique specified in previousversions of this test method. 6.2 Titration Vessei--A jacketed glass vessel approximately 120 mm high and 45 mm in internal diameter and of a form that can be conveniently maintained at 0 to 5"C (32 to 4 I'F). 6.3 Stirrer--Any magnetic stirrer system. 6.4 Electrodes--A platinum wire electrode pair with each wire approximately 12 mm long and 1 mm in diameter. The wires shall be located 5 mm apart and approximately 55 mm below the level of the titration solvent. Clean the electrode pair at regular intervals with 65 % nitric acid and rinse with distilled water before use. 6.5 Buret--Any delivery system capable of measuring titrant in 0.05 mL or smaller graduations.

7. Reagents 7.1 Purity of Reagents--Reagent grade chemicals shall be

not conform to the prescribed limits, or if for reasons of uncertainties in the quality of primary reagents it is considered desirable to determine the molarity of the solution, the solution shall be standardized and the determined molarity used in subsequent calculations. The standardization procedure shall be as follows: 7.4. I. l To standardize, place 50 mL of glacial acetic acid and l mL of concentrated hydrochloric acid (Warning--See Note 4 in a 500-mL iodine number flask. Chill the solution in a bath for approximately l0 min and, with constant swirling of the flask, add from a 10-mL calibrated buret, 5 + 0.01 mL of the bromide-bromate standard solution at the rate of l or 2 drops per second. Stopper the flask immediately, shake the contents, place it again in the ice bath, and add 5 mL of Kl solution in the lip of the flask. After 5 min remove the flask from the ice bath and allow the Kl solution to flow into the flask by slowly removing the stopper. Shake vigorously, add 100 mL ofwater in such a manner as to rinse the stopper, lip and walls of the flask, and titrate promptly with sodium thiosulfate (Na2S203) solution. Near the end of the titration, add l mL of starch indicator solution and titrate slowly to disappearance of the blue color. Calculate the molarity of the bromide-bromate solution as follows: AM2 MI . . . . (5) (2)

(1)

where: M~ -- molarity of the bromide-bromate solution, as Br2, A -- millilitres of Na2S203 solution required for titration of the bromide-bromate solution, and, M2 = molarity of Na2S203 solution, 5 -- millilitres of bromide--bromate solution, and 2 -- number of electrons transferred during redox titration of bromide-bromate solution. Repeat the standardization until duplicate determinations do not differ from the mean by more than +0.002 M. NOTE 4: Warning--Poison corrosive. May be fatal if swallowed. Liquid and vapor causesseverebums. Harmful ifinhaled; rel dens 1.19.

used in all tests. Unless otherwise indicated, it is intended that all reagents shall conform to the specifications of the committee on Analytical Reagents of the American Chemical Society, where such specifications are availablefl Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination. 7.2 Purity of Water--Unless otherwise indicated, references to water shall be understood to mean reagent water as defined by Type III of Specification D 1193. 7.3 Acetic Acid, Glacial--(Warning--See Note 3.)

7,5 Methanol---(Warning--See Note 5.) NtyrE 5: Warning--Flammable. Vapor harmful. Can be fatal or cause blindness if swallowed or inhaled. Cannot be made non-poisonotls.

7.6 Potassium Iodide Solution (150 g/L)--Dissolve 150 g of potassium iodide (KI) in water and dilute to 1 L. 7.7 Sodium Thiosulfate, Standard Solution (0.1 M ) - Dissolve 25 g of sodium thiosulfate (NaaS2Oa.5H:O) in water and add 0.1 g of sodium carbonate (Na2COa) to stabilize the solution. Dilute to 1 L and mix thoroughly by shaking. Standardize by any accepted procedure that determines the molarity with an error not greater than :!:0.0002. Restandardize at intervals frequent enough to detect changes of 0.0005 in molarity. 7.8 Starch Solution---Grind and mix thoroughly 5 g of arrowroot starch and 5 to 10 mg of mercuric iodide (Hgl2) (Warning--See Note 6 with 3 to 5 mL of water. Add the suspension to 2 L of boiling water and boil for 5 to 10 rain. Allow to cool and decant the dear, supernatant liquid into glass-stoppered bottles.

NOTE 3: Warning--Poison, corrosive-combustible, may be fatal if swallowed. Causes severe bums, harmful if inhaled.

7.4 Bromide-Bromate, Standard Solution (0.2500 M as Br2)--Dissolve 51.0 g of potassium bromide (KBr) and 13.92 g of potassium bromate (K.BrOa) each dried at 105"C (220"17) for 30 rain in water and dilute to 1 L. 7.4.1 If the determinations of the bromine number of the reference olefins specified in Section 8 using this solution do "Reagent Chemicals, American Chemical Society Specifications," Am. Chemical Soc., Washington, DC. For suggestions on the testing of reagents not listed by the American Chemical Society, see "Analar of Standards for Laboratory U.K. Chemicals," and the "United States Pharmacopeia."

NOTE 6: Warnlng--Poison. Can be fatal if swallowed. 214

~1~ D 1 1 5 9 TABLE 1

Specimen Size

Bromine Number

Specimen Size, g

0to10 Over 10 to 20 Over 20 to 50 Over 50 to 100 Over 100 to 150 Over 150 to 200

20 to 16 10 to 8 5 to 4 2 to 1.5 1.0 to 0.8 0.8 to 0.6

be suitable.Tap the column during the adding of the gel to permit uniform packing. 8.3.2 To the column add 30 m L of the olcfin to be purified. When the olefln disappears into the gel, fillthe column with methanol. Discard the first1O m L of percolate and collectthe next I0 m L that is the purified olcfln for test oftbe bromine number procedure. Determine and record the density and refractiveindex of the purified samples at 20"C. Discard the remaining percolate. NOTE i0: Caution--If distillation of impure olefins is needed as a pre-purification step, a few pellets of potassium hydroxide should be placed in the distillation flaskand at least iO % residueshould remain to minimize the hazards from decompositionofany peroxidesthat may be present.

7.9 Sulfuric Acid (l+5)--Carefully mix one volume of concentrated sulfuric acid ( H 2 S O 4 , tel dens 1.84) with five volumes of water. NOTE 7: Warning--Poison. Corrosive.Strong oxidizer. Contact with organic material can cause fire. Can be fatal if swallowed.

7.10 Titration Solvent--Prepare 1 L of titration of solvent by mixing the following volumes of materials: 714 mL of glacial acetic acid, 134 mL of 1,1, l-trichloroethane, 134 mL of methanol, and 18 mL of H2SO4(1+5). 7.11 I, 1,1-Trichloroethane--(Warning--See Note 8.) NOTE 8: Warning--Harmful if inhaled. High concentrations can cause unconsciousnessor death. Contact may cause skin irritation and dermatitis.

9. Procedure 9.1 Place 10 mL of l,l,l-trichloroethane in a 50-mL volumetric flask and, by means of a pipet, introduce a test specimen as indicated in Table I. Either obtain the weight of specimen introduced by difference between the weight (to the nearest 1 mg) of the fask before and after addition of specimen or, if the density is known accurately, calculate the weight from the measured volume. Fill the flask to the mark with l,l,l-tfichloroethane and mix well. (Warning--See Note 11.) NOTE 11: Warning--Hydrocarbons, particularly those boiling below 205"C (400°I=),are flammable.

8. Check Procedure 8.1 In case of doubt in applying the procedure to actual samples, the reagents and techniques can be checked by means of determinations on freshly purified cyclohexane or diisobutene. (Warning--See Note 9.) Proceed in accordance with Section 9, using a sample of either 0.6 to 1 g freshly purified cyclohexene or diisobutene (see Table I) or 6 to 10 g of 10 mass percent solutions of these materials in 1,1,1trichlorethane.

9. I. 1 Frequently, the order of magnitude of the bromine number of a specimen is unknown. In this case, a trial test is recommended using a 2-g specimen in order to obtain the approximate magnitude of the bromine number. This exploratory test shall be followed with another determination using the appropriate specimen size as indicated in Table 2. 9.1.2 The test specimen taken shall not exceed 1O mL and the volume of bromide-bromate titrant used shall not exceed 1O mL and no separation of the reaction mixture into two phases shall occur during the titration. Difficulty may be experienced in dissolving specimen of the high boiling ranges in the titration solvent; this can be prevented by the addition of a small quantity of toluene. 9.2 Cool the titration vessel to 0 to 5°C (32 to 41°F) and maintain the contents at this temperature throughout the titration. Switch on the titrimeter, and allow the electrical circuit to become stabilized. 9.3 Introduce 110 mL of titration solvent into the vessel and pipet in a 5-mL aliquot of the sample solution from the 50-mL volumetric flask. Switch on the stirrer and adjust to a rapid stirring rate, but avoid any tendency for air bubbles to be drawn down to the solution. 9.4 Set the end point potential. With each instrument, the manufacturer's instructions should be followed for end point setting and to achieve the sensitivity in the platinum

NOTE 9: Warning--Flammable. 8.2 If the reagents and techniques are correct, values within the following should be obtained: Standard

Bromine Number

Cyclohexene, purified (see 7.3.1, 8.3 and Note 10) Cyclohexene, 10 % solution Diisobutene, purified (see 7.3.1, 8.3, and Note 10) Diisobutene, 10 % solution

187 to 199 (see 9.5) 18 to 20 136 to 144 (see 9.5) 13 to 15

The reference olefins yielding the above results are characterized by the properties shown in Table 2. The theoretical bromine numbers of cyclobexene and diisobutene are 194.6 and 142.4, respectively. 8.3 Purified samples of cyclobexene and diisobutene can be prepared from cyclobexene and diisobutene, s by the following procedure: 8.3.1 Add 65 g of activated silica gel, 75 to 150 I~m (100 to 200 mesh) manufactured to ensure minimum olefln polymerization ° to a column approximately 16 mm in inside diameter and 760 mm in length, that has been tapered at the lower end and that contains a small plug of glass wool at the bottom. A 100-mL buret, or any column that will give a height-to-diameter ratio of the silica gel of at least 30:1, will

TABLE 2

SAvailable from Eastnmn, Rochester, NY, by specifying No. 13019 (cyclohexene)and No. P2125 (diisobutene). 9 Available from W.R. Grace and Company, Davison Chemical Division, Baltimore. M D 21203, by specifyingCode 923.

215

Physical Properties of Purified Olefins

Compound

BoilingPoint, °C

Cyclohexene Diisobutene'~

82.5 to 83.5 101 to 102.5

Density at 20°C, g/mL

0.8100 0.7175 +0.0015 A Only the 2,4,4-tdmethyl-l-penteneIsomer.

Index of Refraction, D Une at 20°C 1.4465 1.4112

4~ D 1159 11.1.1 Repeatability--The difference between successive results obtained by the same operator with the same apparatus under constant operating conditions on identical test material would, in the long run, in the normal and correct operation of the test method, exceed the following values only in one case in twenty. Petroleum distillates: 90 % distillation point under 205"C r = 0.11 (X°'7°) (3) 90 % distillation point between 205 and 327°C r = 0.11 (X°'67) (4) where: X = sample mean. Commercial olefins: r=3 11.1.2 Reproducibility--The difference between two single and independent results obtained by different operators working in different laboratories on identical test material would, in the long run, exceed the following values only in one case in twenty: Petroleum Distillates: 90 % distillation point under 205°C R = 0.72 (X°.7°) (5) 90 % distillation point between 205 and 327"C

electrode circuit specified in 6.1. 9.5 Depending on the titrator apparatus, add the bromidebromate solution manually or by microprocessor control in small increments from the buret. The endpoint of the titration is achieved when the potential reaches the pre-set value (see 9.4) and persists for more than 30 s. 9.6 B l a n k s - - M a k e duplicate blank titrations of each batch of titration solvent and reagents by repeating the entire procedure, using 5 mL of l,l,l-trichloroethane in place of the test aliquot. Less than 0.1 mL of bromide-bromate solution should be required. If more than 0.1 mL is used, discard the analysis, prepare fresh titration solvent and fresh reagents and repeat the analysis. 10. Calculation 10.1 Calculate the bromine number as follows: bromine number = (A - B) (MI) (15.98)

W

(2)

where: A = millilitres of bromide-bromate solution required for titration of the test aliquot, B = millilitres of bromide-bromate solution required for titration of the blank, gl = molarity of the bromide-bromate solution, as Br2, W = grams of test specimen in the aliquot, and 15.98 = factor for converting g of bromine per 100 g of specimen and incorporating molecular weight of bromine (as Br2) and conversion of mL to L.

R = 0.78 (A'o.6~)

(6)

where: X = sample mean. Commercial olefins R = 12II II.2 Bias--The procedure for measuring bromine number has no bias because the value of bromine number can be defined only in terms of a test method.

11. Precision and Bias TM 11.1 Precision--Tbe precision of this test method as determined by the statistical examination of interlaboratory test results is as follows:

12. Keywords 12.1 Aliphatic olefins; bromine number;, electrometric titration; petroleum distillates

io Refer to ASTM Research Report RR: D02-1290 covering the round robin data and statistical analysis for products having 90 % distillation points under 205"C.

l z Provisional value obtained from a limited amount of data.

ANNEXES (Mandatory Information)

A1. REPORTED BEHAVIOR OF COMPOUNDS BY THE ELECTROMETRIC BROMINE NUMBER METHOD A 1.1 Technically, the bromine number is the number of grams of bromine reacting with 100 g of the sample under prescribed conditions. By this definition, bromine consumed by addition, substitution, oxidation, and reactions with sulfur, nitrogen, and oxygen-containing compounds is included in the bromine number of the material. The use of the bromine number under determination in the estimation of olefinic unsaturation depends on the fact that the addition reaction proceeds rapidly and completely under most conditions. The addition of bromine proceeds readily at temperatures down to or below 0°C. Decreasing temperature of reaction, time of contact, and concentration of free bromine

tend to retard both substitution and oxidation reactions. Other factors, such as solvent medium, extent of agitation, and exposure to actinic light, also influence the rate of the various reactions. A1.2 Experience has shown that no single set of test conditions will direct the reaction of bromine in one manner to the exclusion of the others. For this reason, the conditions of bromine number tests are usually established on an empirical basis to give reasonable values with representative materials. AI.3 The possibility of multiple reactions occurring concurrently and the variable behavior to certain materials in 216

q~) D 1159 the presence of bromine imposes an element of uncertainty in the interpretation of results. A knowledge of the material being handled and its response to bromine greatly reduces the risk of misinterpretation. A I.4 Bromine number data have been obtained for a variety of petroleum hydrocarbons and certain nonhydrocarbons associated with petroleum, by the electrometer bromine number procedure. These data, which

TABLE A1.1 Compound

were submitted by c o o p e r a t o r s , are presented in Table A I. 1. AI.5 It is intended that this information serve as a general guide in the interpretation of bromine numbers on petroleum products. It is recognized that the bromine number data recorded in this table are of limited value owing to incompleteness; however, it is considered that their usefulness will be amplified as more bromine number data are contributed by cooperators.

Reported Behavior of Compounds by the Electrometdc Bromine Number Method Bromine Number

Purity, ~A

Theory

Found

0.0 0.0 0.0 0.0 0.0

0.0 0.0 0.1 0.0 0.1

228.0 228.0 189.9 189.9 189.9 189.9 189.9 162.8 162.8 162.8 142.4 142.4 142.4 114.1 95.1 87.7 81.4 76.0 71.2

208 235 181 189 189 193 191.4 136 163 163 132 139 149 111.4 82.9 81.4 70.8 62.9 62.8

Deviation

Paraffins tPHexane 2-Methylhexane a-Heptane w-Octane 2,2,4-Tdmethylpentane

99.96 • 99.88 c 99.94 99.96

1-Pentene

99.7 99.91 99.80 99.83 99.87 99.94 ... 99.8 99.85 99.80 99.7 ... 99.94 99.89 99.9 99.8 99.7 99.8 99.94

0.0 0.1 +0.1 0.0 +0.1

Straight Chain Ok)fins

trans-2-Pentene 1-Hexene

cis-2-Hexene trans-2-Hexene cis-3-Hexene trans-3-Hexene 1-Heptene

trans-2-Heptene trans-3-Heptene 1-Octene 2-Octene

trans-4-Octene 1-Decene 1-Dodecene 1-Tridecene 1-Tetradecene 1-Pentadecene 1-Hexadecene

-20 +7 -9 -1

-1 +3 +1.5 -27 0 0 -10 -3 +7 -2.7 - 12.2 -6.3 -10.6 - 13.1 -8.4

Branched Chain Ok)fins 2-Methyl-1-butene 2-Methyl-2-butene 2,3-Dimethyl-1-butene 3,3-Dimethyl-1-butene 2-Ethyl-1-butene 2,3-Dimethyl-2Joutene 2-Methyl-1-peatene 3-Methyl-1-pent(me 4-Methyl-I -pentene 2-Methyl-2-pentene 3-Methyl-cls-2-pentene 3-Methyl-trans-2-pentene

4-Methyl-cls.2-pentene 4-Methyl-trans-2-pentene 2,3,3-Tdmethyl-l-butene 3-Methyl-2-Ethyl-1-butene 2,3-Dimethyl-l-pentene 2,4-Dimethyl-l-pentene 2,3-Dimethyl-2-pentene 4,4-Dimethyl-cls-2-pentene 4,4-Dimethyl-trans-2-pentene 3-Ethyl-1-pentene 3-Ethyl-2-pentene 2-Methyl-1-hexene 5-Methyl-1-hexene 3-Methyl-cls-2.hexene 2-Methyl4rans-3-hexene 2-Methyl-3-Ethyl-1-pentene 2,4,4-Trimethyl-l.pentene 2,4,4-Tdmethyl-2-pentene Diisobutene

99.90 99.94 99.86 99.91 99.90 99.90 99.92 99.70 99.82 99.91 99.85 99.86 99.92 99.75 99.94 99.8 99.80 99.87 99.6 99.79 99.91 99.85 99.80 99.88 99.80 99.8 99.9 99.81 99.91 99.92 o

228.0 228.0 189.9 189.9 189.9 189.9 189.9 189.9 189.9 189.9 189.9 189.9 189.9 189.9 162.8 162.8 162.8 162.8 162.8 162.8 162.8 162.8 162.8 162.8 162.8 162.8 162.8 142.4 142.4 142.4 142.4

217

231.8 235 194 167 198 191 182 152 176 190 193.7 191 190 190 161 165.4 158.5 152.8 162.3 159 158 173.1 165 161 154 163.6 163.4 139.8 137.0 141.2 139.8 a

+3.8 +7 +4 -23 +8 +1 -8 -38 - 14 0 +3.8 +1 0 0 -2 +2.6 -4.3 -10.0 -0.5 -4 -5 +10.3 +2 -2 -9 +0.8 +0.6 -2.6 -5.4 -1.2 -2.6

~1~) D 1159 TABLE A1,1 Compound

Continued Bromine Number

Purity, ~,A

2.Ethyl-1-hexene 2,3-Dimethyl-2-bexene 2,5-Dimethyl-2-hexene 2,2-Dimethyl-trans-3-hexene Tdisobutene

• 99.71 99.8 99.80 99.0 p

4-Ethenyl-1-cyolohexene (4-vinyl-1-cyclohexene) di-1,8(9)-p-Menthadiene (dipentene)

99.90 98-100 a

2-Methyl-l,3-butedlene (isoprene) c/s.1,3-Pentediene 2-Methyl-1,3-Pentadlene 2,3-Dimethyl-1,3-Butadkme

99.96 99.92 99.92 95+ ~ 99.93

1,2-Pentediene 1,4-Pentediene 2,3-Pentediene 1,5-Hexediene

99.66 99.93 99.85 99.89

Theory

Found

Deviation

142.4 142.4 142.4 142.4 95

140.2 143 142.8 139 57.5

-2.2 +1 +0.4 -3 -37.5

295.5 234.6

210 H 225.2

(-85) -9.4

470 470 470 389 389

235.7 285.3 234 197.3 186.1

-234 -185 -236 - 192 -203

230 185 227 352

-240 -285 -243 -37

153.4 135.3 135.2

123.6 133.2 0.0

-29.8 -2.1 -135.2

234.6 194.6 194.6 194.6 166 166 166.2 145.0 145.0 145.0 145 145 137.7

237 193.2 192.8 ° 209 162 194 167.7 150.9 140.9 147.0 139 146.6 134

+2 -1.4 -1.8 +14 -4 -2 +1.5 +5.9 -4.1 +2.0 -8 +1.6 -4

0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0,0 0.0

0.1 0.1 0.0 0.0 0.0 0.0 0 0.3 0.0 0.1 0.3 0.0 0.7

+0.1 +0.1 0.0 0.0 0.0 0.0 0 +0.3 0.0 +0.1 +0.3 0.0 +0.7

0.0 0.0 0.0 0.0 0.0 0.0 0.0

0.0 0 0.2 0.0 0.0 0.0 0

0.0 0 +0.2 0.0 0.0 0.0 0

0.0 0.0

11.8 3.9

+11.8 +3.9

0.0 0.0 0.0

0,0 0 0.0

0.0 0 0.0

Nonconjugated Cyclic DIolefins

Conjugated DIoleflns

trans.1,3-Pentediene

Nonconjugated Dioleflns 470 470 470 389

Aromatics with Unsaturated Side Chains Phenylethylene (styrene) Methylphenylethylene (a.methylstyrene) Amylbenzene

d J 97.8 x

Cyclopentene Cyolohexene Cyclohexene 1-Methyicyclopentene 1-Methylcyclohexene Ethenyicyclopentene (Vinyicyclopentene) Ethylldenecyolopentane 1,2-Dimethyicyclohexene 3-Cyclopentyl-1-propene Ethylk:lenecyclohexane Ethenyicyclohexane (Vinylcyclohexane) 1-Ethyicyclohexene Indene

99.97 99.98 o 99.86 99.82 99.91 99.96 99.94 99.87 99.86 99.95 99.83 ...

Benzene Toluene Xykme Xylene Xylene opropylbenzene (Cumene) 2,4-Tdmethylbenzene (Pseudooumene) 3,5-Tdrnethylbenzene (Mesltylene) 3-Oimethyl-4-ethylbenzene 2,4,5.Tetramethylbenzene (Durene) 2,3,5-Tetrarnethylbenzene (Isodurene) t-Butylbenzene t-Amylbenzene

99.98 99.97 99+ L 99+" 99+ L 99.95 99.67 M 99:9 99.86 " 99.73 a P

Benylbenzene (BIphenyl) Naphthalene 2,3,4-Tetrahydronaphthalene (Tetra,n) Methylnaphthalene Methylnaphthalene 3-Dihydrolndene (Indan) Cyclohexylbenzene

M 99.96 99.9 99.78 99.91 99.9 99.93

Athracene Benanthrene

M u

Methyicyclopentene Methyicyolohexane Dipropylcydopentane

99.99 s 99.97 99.8

Cyclic Oleflns

Aromatics,Monocyolic

Aromatics,Bicyolic

Aromatics, Polycyclic

Cyc~oaraf~ns

218

~1~ D 1159 TABLE A1.1

Compound

Continued Bromine Number

Purity, ~A

Theory

Found

99.94 99.71 99.95

0.0 0.0 0.0

0.0 0.0

0.0 0.0

cis.Oecahydronephthelene (ci$-decalin) trans-Decahydronaphthalene(trans-deca~)

99.95 98+ I 98+ ~

0.0 0.0 0.0

0 0.0 0.11 1.64

O 0.0 +0.11 +1.64

Thenethiol (ethyl mercapten) Thlapsntane (ethyl sulfide) 3-DithJabutane (methyk:ilsulflde) Diacyclobutane (trimethylano sulfide) Iophene Tetracyclopentane (tetrahydrothiopheno) •Oithlahexane (dlathyldlaulflde) tert-ethyl-2-propanethiol(tart-butyl merceptan) Pantanethiol (amyl mercaptan)

99.95 99.94 99.97 99.95 99.99 99.95 99.90 99.92 99.92

Broidine iodine Mathylpyridine Mathylpyrkline 1,6-Trimethylpyridine 5-nonyl) pyndine mole Mathylpyrrole 1-Dimethylpyrrole 1-Dimethylpyrrole 1-Dimethyl-3-ethylpyrro~e 1-Butyl pyrrole

99.85 o 99.90 99+ N 99+ N M 99.99 98+ o 98+ o 99.9 P 98+ o 98+ °

Acetone Methylethylketone

o R

Ethenolamine Ethylene dichloride Ethylene dibremida Tetraethyllaad (TEL) Tetrarnethyllead (TML) AK 33X "Ethyl" orange dye

M N N s s s s

cie-Hexahydromden(cls.Hyddndan) trans-Hexahydroindan (trans-Hydrindan) t-Butylcyclobexane Didepsntylcyclopentane

Deviation

Sulfur Compounds 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

209 184 1.1 214 0.4 183 0.4 141 83

+208 +184 +1.1 +214 +0.4 +183 +0.4 +141 +83

0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

11,8 1.4 0.9 1.7 2.7 1.4 873 708 484 869 248 472

+11.8 +1.4 +0.9 +1.7 +2.7 +1.4 +873 +708 +484 +869 +248 +472

0.0 0.0

0.0 0.0

0.0 0.0

0.0 0.0 0.0 (49.5) r (59.8) r (73.4) r ...

1.5 0.0 0.0 52.7 62.6 0.8. 0.0

NitrogenCompounds

Oxygen Compounds

Miscellaneous

A API Standard Samples, unless otherwise noted, a Phillips research grade product. c Phillips pure grade product, distilled, heart-cut percolated through Si gel. o Average value obtained in September 1957 Cooperative Program on purified Eastman product. • Dow Research Chemical. P Pudty not stated. o Hercules Inc., expsdmental sample. H Approximate value. i From Penn State University. a Eastman white label product, distilled, 50-ram pressure just prior to test. K M C and B chemical. Purity determined by GC, impurities not identified. L Phillips pure grade product. M Eastman white label product. N Purity estimated by spectraand GLC. o Samples supplied by API Project 52. P Purity estimated from freezing point. o B and A Reagent chemical (Code No. 1004). R M C end B chemical (Code No. 2609). s Ethyl Corporation products. r Calculated values based on the reactk~ of one mole of bromine with the orgenometallic compound.

219

+1.5 0.0 0.0 (+3.2) (+2.8) (-72.8) ...

~1~) D 1159

A2. CALCULATION OF OLEFIN CONTENT TABLE A2.1

A2.1 Scope A2.1.1 This procedure covers the calculation of the volume percentage of olefins from the bromine number in straight-run, reformed, cracked gasolines and commercial gasolines that have a 90 % boiling point below 200"C (392°F); and turbine fuel and kerosine etc., boiling below 315"C (600*F) and having a bromine number of less than 20. A2.1.2 The procedure is not intended for synthetic olefinic blends of pure or nearly pure compounds having a boiling range of less than 14°C (25"1=). A2.1.3 Sulfur, nitrogen, or oxygen compounds, if present in concentrations of 1 volume % or greater will reduce the accuracy (see Note A2. I). A2.2 Procedure A2.2.1 Determine the bromine number in accordance with this test method. anomalous data in the bromine number test, see Annex AI. In the case of special samples that contain high concentrations of certain hydra carbon types, caution in the interpretation of the bromine number is needed. A2.2.2 Calculate the concentration of olefins from the bromine number as follows: olefins, mass % = f BM/160 (A2.1) where: f = boiling range correction (see Fig. A2.1 and Table A2.1), B -- bromine number expressed as grams of bromine/100 g of sample, and M = molecular weight (relative molecular mass) of olefins (see Table A2.2). NOTE A2.2--The boiling range correction is needed for cracked naphthas since it is an empirical fact that the percentage by volume of olefins is higher in the lower boiling fractions and that these olefins are also of lower relative molecular mass (molecular weight). A2.2.3 Using the 50 % boiling point (see Test Method D 86), estimate the average density of the olefins using Fig. A2.2. Multiply the mass percentage of olefins (as calculated in A2.2.2) by the ratio of the density ofthe original sample to the density of the olefins to obtain percentage by volume as follows: olefins, volume % -- (A/B) x C (A2.2)

too

' I

¢J

0

I i

L

I

|

O

~O

I

,

0.775 0.750 0.725 0.700

50 ~ Boiling Point, oC (OF)

Average Molecular Weight of Ok)fins

38 (I00) 66 (150) 93 (200) 121 (250) 149 (300) 177 (350) 204 (400) 232 (450)

72 83 96 110 127 145 164 186

*'"° I Ce00=

!

i

: 2OO

, ~00

!

l

I c.,~ O$30 Y__. .2D FIG. A2.2

i aOO

......

:¢O

Relation of Density to the SO % Boiling Point

where: A = density of the sample, B = average density of the olefins, and C -- mass percentage of olefins. A2.3 Precision n2

|

5~O 550 Boiliml I ~ tte,t,o! ~o [NI Ib~ml).¢~; Fo~ FIG. A2.1 Boiling Range Correction too

0.800

A2.3.1 The precision of this test method as obtained by statistical examination of interlaboratory test results is as follows: A2.3.1.I Repeatability---The difference between successive testresultsobtained by the same operator with the same apparatus under constant operating conditions on identical test material would, in the long run, in the normal and correct operation of the test method, exceed the following

I'om

f o.7o

Boiling Range, *C (OF) Initial to End, (see Test Method D 86) 0 (0) 7 (13) 14 (25) 21 (38) 2s (50) 38 (68) 43 (78) 53 (95) 62 (112) 72 (130) 95 (152) 99 (178) 125 or greater (225)

TABLE A2.2 Relation of Average Relative Molecular Mass (Molecular Weight) to 50 % Boiling Point by Test Method O 86

NOTE A2. I m F o r information on types o f c o m p o u n d s that m a y yield

I

Boiling Range Corrections for Olefins

Boiling Range Correction, J" 1.50 0.975 0.950 0.925 0.90o 0.875 0.850 0.825

*~O ZOO 250

to The results of cooperative data were last published in the 1966 Annual Book of ASTM Standards, Part 17, and are filed at ASTM Headquarters as Research Report No. RR36:D-2.

220

~) O 1159 only in one case in twenty:

values only in one case in twenty: Straight-Run Fuels (less than I volume % olefins) 0.2

Straight-Run Fuels (less than 1 volume % olefins) 0.4

Cracked Gasolines (I to 25 volume % olefins) 0.6

A2.3.1.2 Reproducibility---The difference between two single and independent results, obtained by different operators, working in different laboratories on identical test material would, in the long run, in the normal and correct operation of the test method, exceed the following values

Cracked Gasolines (l to 25 volume % olefins) 3

A2.3.2 Bias--The procedure for calculating olefin content has no bias because the value obtained can be defined only in terms of a procedure. NOTE A2.3--The precision for this test method was not obtained in accordance with RR: D02-1007.

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent righta, and the risk of Infringement of such rights, are entirely their own responsibility. This standard is eubject to revision at any time by the responsible technical committee and must be reviewed every five years and If not revised, either reapproved or withdrawn. Your comments are invited either for revision of this Mandard or for additional standards and should be addressed to ASTM Hesdquartere. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend, ff you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103.

221

(~ll~ Designation: D 1160 - 95 Standard Test Method for Distillation of Petroleum Products at Reduced Pressure This standard is issued under the fixed designation D 1160; the number immediately following the designation indtcatcs the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last rcapproval. A superscript epsilon (~) indicates an editorial change since the last revision or reapproval.

This standard has been approved for u~e by agencies oJ'the Department of Defense. Consult the DoD lndev o/Spectllcations and Standards,/or the ,~pec~[icyear of tssue whwh has been adopted by the Department of Defense.

1. Scope 1.1 This test method covers the determination, at reduced pressures, of the range of boiling points for petroleum products that can be partially or completely vaporized at a maximum liquid temperature of 400"C. Both a manual method and an automatic method are specified. 1.2 In cases of dispute, the referee test method is the manual test method at a mutually agreed upon pressure. 1.3 The values stated in SI units are to be regarded as the standard. The values in parentheses are for information only. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements, see Notes 2, 4, 11, 12, and A3.2. 2. Referenced Documents

2.1 ASTM Standards: D 613 Test Method for Ignition Quality of Diesel Fuels by the Cetane Method 2 D 1193 Specification for Reagent Water 3 D 1250 Guide for Petroleum Measurement Tables 4 D 1298 Practice for Density, Relative Density (Specific Gravity), or API Gravity of Crude Petroleum and Liquid Petroleum Products by Hydrometer Method 4 D 4052 Test Method for Density and Relative Density of Liquids by Digital Density Meter 5 D4057 Practice for Manual Sampling of Petroleum and Petroleum Products 5 D 4177 Practice for Automatic Sampling of Petroleum and Petroleum Products 5 3. Terminology 3.1 Descriptions of Terms Specific to This Standard." 3.1.1 atmospheric equivalent temperature (AET)--the temperature converted from the observed temperature using equation A7.1 or using Tables 1 through 6. The AET is the expected distillate temperature if the distillation was per-

formed at atmospheric pressure and there was no thermal decomposition. 3.1.2 end point (EP) or final boiling point (FBP)--the maximum vapor temperature reached during the test. 3.1.3 initial boiling point (IBP)--the vapor temperature that is observed at the instant the first drop of condensate falls from the lower end of the condenser tube.

4. Summary of Test Method 4.1 The sample is distilled at an accurately controlled pressure between 0.13 and 6.7 kPa (1 and 50 mm Hg) under conditions that are designed to provide approximately one theoretical plate fractionation. Data are obtained from which the initial boiling point, the final boiling point, and a distillation curve relating volume percent distilled and atmospheric equivalent boiling point temperature can be prepared. 5. Significance and Use 5.1 This test method is used for the determination of the distillation characteristics of petroleum products and fractions that may decompose if distilled at atmospheric pressure. This boiling range, obtained at conditions designed to obtain approximately one theoretical plate fractionation, can be used in engineering calculations to design distillation equipment, to prepare appropriate blends for industrial purposes, to determine compliance with regulatory rules, to determine the suitability of the product as feed to a refining process, or for a host of other purposes. 5.2 The boiling range is directly related to viscosity, vapor pressure, heating value, average molecular weight, and many other chemical, physical, and mechanical properties. Any of these properties can be the determining factor in the suitability of the product in its intended application. 5.3 Petroleum product specifications often include distillation limits based on data by this test method. 5.4 Many engineering design correlations have been developed on data by this test method. These correlative methods are used extensively in current engineering practice. 6. Apparatus 6.1 The vacuum distillation apparatus, shown schematically in Fig. 1, consists in part of the components described below plus others that appear in Fig. 1 but are not specified, either as to design or performance. Some of these parts are not essential for obtaining satisfactory results from the tests but are desirable components of the assembly for the purpose of promoting the efficient use of the apparatus and ease of its operation. Both manual and automatic versions of the

t This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.08 on Volatility. Current edition approved Apr. 15, 1995. Published June 1995. Originally published as D 1160 - 5IT. Last previous edition D 1160 - 93a. 2 Annual Book of ASTM Standards, Vol 05.04. 3 Annual Book of ASTM Standards, Vol I 1.01. 4 Annual Book of ASTM Standards, Vol 05.01. s Annual Book of ASTM Standards, Vol 05.02.

222

~@) D 1160 TABLE 1

Temperature-Pressure Conversion Table for Petroleum Hydrocarbons (From 0.13 kPa (1 mm Hg)) AET Boiling Point at 101.3 kPa (760 mm Hg) Absolute Pressure

Vapor Temperature

Degrees Celsius 0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

35 40 45 50 55

195 202 209 216 222

196 203 210 217 224

196 203 210 217 224

198 205 211 218 225

198 205 211 218 225

199 206 213 220 226

199 206 213 220 226

201 207 214 221 228

201 207 214 221 228

202 209 216 222 229

60 65 70 75 80

229 236 242 249 256

230 237 244 251 257

230 237 244 251 257

232 238 245 252 259

232 238 245 252 259

233 240 247 253 260

233 240 247 253 260

234 241 248 255 261

234 241 248 255 261

236 242 249 256 263

85 90 95 100 105

263 269 276 282 289

264 270 277 284 290

264 270 277 284 290

265 272 278 285 292

265 272 278 285 292

266 273 280 286 293

266 273 280 286 293

268 274 281 288 294

268 274 281 288 294

269 276 282 289 295

110 115 120 125 130

295 302 308 315 321

297 303 310 316 323

297 303 310 316 323

298 305 311 318 324

298 305 311 318 324

299 306 312 319 325

299 306 312 319 325

301 307 314 320 327

301 307 314 320 327

302 308 315 321 328

135 140 145 150 155

328 334 341 347 353

329 336 342 348 355

329 336 342 348 355

330 337 343 350 356

330 337 343 350 356

332 338 345 351 357

332 338 345 351 357

333 339 346 352 359

333 339 346 352 359

334 341 347 353 360

160 165 170 175 180

360 366 372 379 385

361 367 374 380 386

361 367 374 380 386

362 369 375 381 387

362 369 375 381 387

364 370 376 382 389

364 370 376 382 389

365 371 377 384 390

365 371 377 384 390

366 372 379 385 391

185 190 195 200 205

391 397 404 410 416

392 399 405 411 417

392 399 405 411 417

394 400 406 412 419

394 400 406 412 419

395 401 407 414 420

395 401 407 414 420

396 402 409 415 421

396 402 409 415 421

397 404 410 416 422

210 215 220 225 230

422 428 434 441 447

423 430 436 442 448

423 430 436 442 448

425 431 437 443 449

425 431 437 443 449

426 432 438 444 450

426 432 438 444 450

427 433 439 445 451

427 433 439 445 451

428 434 441 447 453

235 240 245 250 255

453 459 465 471 477

454 460 466 472 478

454 460 466 472 478

455 461 467 473 479

455 461 467 473 479

456 462 468 474 480

456 462 468 474 480

458 464 470 476 482

458 464 470 476 482

459 465 471 477 483

260 265 270 275 280

483 489 495 501 506

484 490 496 502 508

484 490 496 502 508

485 491 497 503 509

485 491 497 503 509

486 492 498 504 510

486 492 498 504 510

488 493 499 505 511

488 493 499 505 511

489 495 501 506 512

285 290 295 300 305

512 518 524 530 536

514 519 525 531 537

514 519 525 531 537

515 521 526 532 538

515 521 526 532 538

516 522 528 533 539

516 522 528 533 539

517 523 529 535 540

517 523 529 535 540

518 524 530 536 542

310 315 320 325 330

542 547 553 559 565

543 548 554 560 566

543 548 554 560 566

544 550 555 561 567

544 550 555 561 567

545 551 557 562 568

545 551 557 562 568

546 552 558 563 569

546 552 558 563 569

547 553 559 565 570

335 340 345 350

570 576 582 587

571 577 583 588

571 577 583 588

573 578 584 590

573 578 584 590

574 579 585 591

574 579 585 591

575 581 586 592

575 581 586 592

576 582 587 592

223

~ TABLE 2

D 1160

Temperature-Pres sur e Conversion Table f o r Petroleum Hydrocarbons (From 0.27 kPa (2 mm Hg)) AET Boiling Point at 101,3 kPa (760 mm Hg) Absolute Pressure

Vapo¢ Temperature

Degrees Celsius 0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

35 40 45 50 55

181 166 195 201 208

183 169 196 203 209

183 169 196 203 209

184 191 197 204 211

164 191 197 204 211

185 192 199 205 212

185 192 199 205 212

187 193 200 207 213

167 193 200 207 213

166 195 201 208 215

60 65 70 75 80

215 221 228 234 241

216 222 229 236 242

216 222 229 236 242

217 224 230 237 243

217 224 230 237 243

218 225 232 238 245

218 225 232 238 245

220 226 233 240 246

220 226 233 240 246

221 226 234 241 247

85 90 95 100 105

247 254 260 267 273

249 255 262 268 275

249 255 262 268 275

250 256 263 269 276

250 256 263 269 276

251 258 264 271 277

251 256 264 271 277

253 259 266 272 278

253 259 266 272 278

254 260 267 273 280

110 115 120 125 130

280 286 293 299 305

281 287 294 300 307

281 267 294 300 307

282 289 295 301 308

282 269 295 301 308

284 290 296 303 309

284 290 296 303 309

285 291 298 304 310

285 291 298 304 310

286 293 299 305 312

135 140 146 150 155

312 318 324 331 337

313 319 326 332 338

313 319 326 332 338

314 321 327 333 339

314 321 327 333 339

315 322 326 334 341

315 322 328 334 341

317 323 329 336 342

317 323 329 336 342

318 324 331 337 343

160 165 170 175 180

343 349 356 362 368

344 351 357 363 369

344 351 357 363 369

346 352 356 364 370

346 352 358 364 370

347 353 359 365 372

347 353 359 365 372

348 354 361 367 373

348 354 361 367 373

349 356 362 368 374

185 190 195 200 205

374 380 386 393 399

375 382 386 394 400

375 382 386 394 400

377 383 369 395 401

377 383 369 395 401

378 384 390 396 402

378 384 390 396 402

379 385 391 397 404

379 385 391 397 404

380 386 393 399 405

210 215 220 225 230

405 411 417 423 429

406 412 418 424 430

406 412 418 424 430

407 413 419 425 431

407 413 419 425 431

408 414 420 427 433

408 414 420 427 433

410 416 422 428 434

410 416 422 428 434

411 417 423 429 435

235 240 245 250 255

435 441 447 453 459

436 442 448 454 460

436 442 448 454 460

437 443 449 455 461

437 443 449 455 461

439 444 450 456 462

439 444 450 456 462

440 446 452 458 463

440 446 452 458 463

441 447 453 459 465

260 265 270 275 280

465 471 476 482 488

466 472 478 484 489

466 472 478 484 489

467 473 479 485 491

467 473 479 485 491

468 474 480 486 492

468 474 480 486 492

469 475 481 487 493

469 475 481 487 493

471 476 482 488 494

285 290 295 300 305

494 500 506 511 517

495 501 507 513 518

495 501 507 513 518

496 502 508 514 520

496 502 508 514 520

498 503 509 515 521

498 503 509 515 521

499 504 510 516 522

499 504 510 516 522

500 506 511 517 523

310 315 320 325 330

523 529 534 540 546

524 530 536 541 547

524 530 536 541 547

525 531 537 542 548

525 531 537 542 546

526 532 538 544 549

526 532 538 544 549

528 533 539 545 550

528 533 539 545 550

529 534 540 546 552

335 340 345 350

552 557 563 569

553 558 564 570

553 558 564 570

554 559 565 571

554 559 565 571

555 561 566 572

555 561 566 572

556 562 567 573

556 562 567 573

557 563 569 574

224

(@) D 1160 TABLE 3

Temperature-Pressure Conversion Table for Petroleum Hydrocarbons (From 0.67 kFa (5 mm Hg)) AET Boiling Point at 101.3 kPa (760 mrn Hg) Absolute Pressure

Vapor Temperature

Degrees Celsius 0.0

0.5

1.0

1.5

2.0

2,5

3.0

3.5

4.0

4,5

35 40 45 50 55

162 169 175 181 188

163 170 176 183 189

163 170 176 183 189

165 171 178 184 191

165 171 178 184 191

166 172 179 185 192

166 172 179 185 192

167 174 180 187 193

167 174 180 187 193

169 175 181 188 194

60 65 70 75 80

194 201 207 214 220

196 202 208 215 221

196 202 208 215 221

197 203 210 216 223

197 203 210 216 223

198 205 211 217 224

198 205 211 217 224

200 206 212 219 225

200 206 212 219 225

201 207 214 220 226

85 90 95 100 105

226 233 239 245 252

226 234 240 247 253

228 234 240 247 253

229 235 242 248 254

229 235 242 248 254

230 236 243 249 255

230 236 243 249 255

231 238 244 250 257

231 236 244 250 257

233 239 245 252 258

110 115 120 125 130

258 264 270 277 283

259 265 272 278 284

259 265 272 278 284

260 267 273 279 285

260 267 273 279 285

262 268 274 280 287

262 266 274 280 287

263 269 275 282 288

263 269 275 282 268

264 270 277 283 289

135 140 145 150 155

289 295 301 308 314

290 296 303 309 315

290 296 303 309 315

292 298 304 310 316

292 298 304 310 316

293 299 305 311 317

293 299 305 311 317

294 300 306 312 319

294 300 306 312 319

295 301 308 314 320

160 165 170 175 180

320 326 332 338 344

321 327 333 339 345

321 327 333 339 345

322 328 334 341 347

322 328 334 341 347

323 330 336 342 348

323 330 336 342 348

325 331 337 343 349

325 331 337 343 349

326 332 338 344 350

185 190 195 200 205

350 356 362 368 374

351 357 363 369 375

351 357 363 369 375

353 359 365 371 377

353 359 365 371 377

354 360 366 372 378

354 360 366 372 378

355 361 367 373 379

355 361 367 373 379

356 362 368 374 380

210 215 220 225 230

380 386 392 398 404

381 387 393 399 405

381 387 393 399 405

383 389 395 400 406

383 389 395 400 406

384 390 396 402 408

384 390 396 402 408

385 391 397 403 409

385 391 397 403 409

386 392 398 404 410

235 240 245 250 255

410 416 422 428 433

411 417 423 429 435

411 417 423 429 435

412 418 424 430 436

412 418 424 430 436

413 419 425 431 437

413 419 425 431 437

415 421 426 432 438

415 421 426 432 438

416 422 428 433 439

260 265 270 275 280

439 445 461 457 462

440 446 452 458 464

440 446 452 458 464

442 447 453 459 465

442 447 453 459 465

443 449 454 460 466

443 449 454 460 466

444 450 456 461 467

444 450 456 461 467

445 451 457 462 468

285 290 295 300 305

468 474 480 485 491

469 475 481 487 492

469 475 481 487 492

471 476 482 488 493

471 476 482 488 493

472 477 483 489 495

472 477 483 489 495

473 479 484 490 496

473 479 484 490 496

474 480 485 491 497

310 315 320 325 330

497 503 508 514 519

498 504 509 515 521

498 504 509 515 521

499 505 510 516 522

499 505 510 516 522

500 506 512 517 523

500 506 512 517 523

501 507 513 518 524

501 507 513 518 524

503 508 514 519 525

335 340 345 350

525 531 536 542

526 532 537 543

526 532 537 543

527 533 539 544

527 533 539 544

529 534 540 545

529 534 540 545

530 535 541 546

530 535 541 546

531 536 542 547

225

~) TABLE 4

D 1160

Temperature-Pressure Conversion Table for Petroleum Hydrocarbons (From 1.33 kPa (10 mm Hg)) AET Boiling Point at 101.3 kPa (760 mm Hg) Absolute Pressure

Vapor Temperature

Degrees Celsius 0.0

0.5

1.0

1.5

2.0

2.5

3,0

3,5

4.0

4.5

35 40 45 50 55

147 153 159 166 172

148 154 161 167 173

148 154 161 167 173

149 156 162 168 175

149 156 162 168 175

151 157 163 170 176

151 157 163 170 176

152 158 164 171 177

152 158 164 171 177

153 159 166 172 178

60 65 70 75 80

178 185 191 197 203

160 166 192 198 205

180 186 192 198 205

181 187 193 200 206

181 187 193 200 206

182 188 195 201 207

182 188 195 201 207

183 190 196 202 208

183 190 196 202 208

185 191 197 203 210

65 90 95 100 105

210 216 222 228 234

211 217 223 229 235

211 217 223 229 235

212 218 224 231 237

212 218 224 231 237

213 219 226 232 238

213 219 226 232 238

215 221 227 233 239

215 221 227 233 239

216 222 228 234 240

110 115 120 125 130

240 247 253 259 265

242 248 254 260 266

242 248 254 260 266

243 249 255 261 267

243 249 255 261 267

244 250 256 262 269

244 250 256 262 269

245 251 258 264 270

245 251 258 264 270

247 253 259 265 271

135 140 145 150 155

271 277 283 289 295

272 278 284 290 296

272 278 284 290 296

273 279 285 292 298

273 279 285 292 298

275 281 287 293 299

275 281 267 293 299

276 282 288 294 300

276 282 288 294 300

277 283 289 295 301

160 165 170 176 180

301 307 313 319 325

302 308 314 320 326

302 308 314 320 326

304 310 316 321 327

304 310 316 321 327

305 311 317 323 329

305 311 317 323 329

306 312 318 324 330

306 312 318 324 330

307 313 319 325 331

185 190 196 200 205

331 337 343 349 355

332 338 344 350 356

332 338 344 350 356

333 339 345 351 357

333 339 345 351 357

335 341 346 352 358

335 341 346 352 358

336 342 348 354 359

336 342 348 354 359

337 343 349 355 361

210 215 220 225 230

361 366 372 378 384

362 368 373 379 385

362 368 373 379 385

363 369 375 380 386

363 369 375 380 386

364 370 376 382 387

364 370 376 382 387

365 371 377 383 389

365 371 377 383 389

366 372 378 384 390

235 240 245 250 255

390 396 401 407 413

391 397 403 408 414

391 397 403 408 414

392 398 404 410 415

392 398 404 410 415

393 399 405 411 416

393 399 405 411 416

394 400 406 412 418

394 400 406 412 418

396 401 407 413 419

260 265 270 275 280

419 425 430 436 442

420 426 431 437 443

420 426 431 437 443

421 427 433 438 444

421 427 433 438 444

422 428 434 439 445

422 428 434 439 445

423 429 435 441 446

423 429 435 441 446

425 430 436 442 447

285 290 295 300 305

447 453 459 464 470

449 454 460 466 471

449 454 460 466 471

450 455 461 467 472

450 455 461 467 472

451 456 462 468 473

451 456 462 468 473

452 458 463 469 475

452 458 463 469 475

453 459 464 470 476

310 315 320 325 330

476 481 487 493 498

477 482 488 494 499

477 482 488 494 499

478 484 489 495 500

478 484 489 495 500

479 485 490 496 502

479 485 490 496 502

480 486 491 497 503

480 486 491 497 503

481 487 493 498 504

335 340 345 350

504 509 515 520

505 510 516 522

505 510 516 522

506 512 517 523

506 512 517 523

507 513 518 524

507 513 518 524

508 514 519 525

508 514 519 525

509 515 520 525

226

~ D 1160 TABLE 5

Temperature-Pressure Conversion Table for Petroleum Hydrocarbons (From 2.67 kPa (20 mm Hg)) AET Bc~ling Point at 101.3 kPa (760 mm Hg) Absolute Pressure

Vapor Temperature

Degrees Celsius 0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

35 40 45 50 55

131 137 143 149 155

132 138 144 151 157

132 138 144 151 157

133 139 146 152 158

133 139 146 152 158

135 141 147 153 159

135 141 147 153 159

136 142 148 154 160

136 142 148 154 160

137 143 149 155 162

60 65 70 75 80

162 168 174 180 186

163 169 175 181 187

163 169 175 181 187

164 170 176 182 188

164 170 176 182 188

165 171 177 183 190

165 171 177 183 190

166 173 179 185 191

166 173 179 185 191

168 174 180 186 192

85 90 95 100 105

192 198 204 210 216

193 199 205 211 217

193 199 205 211 217

194 200 206 212 218

194 200 206 212 218

196 202 208 214 220

196 202 208 214 220

197 203 209 215 221

197 203 209 215 221

198 204 210 216 222

110 115 120 125 130

222 228 234 240 246

223 229 235 241 247

223 229 235 241 247

224 230 236 242 248

224 230 236 242 248

226 232 238 244 250

226 232 238 244 250

227 233 239 245 251

227 233 239 245 251

228 234 240 246 252

135 140 145 150 155

252 258 264 270 276

253 259 265 271 277

253 259 265 271 277

254 260 266 272 278

254 260 266 272 278

256 261 267 273 279

256 261 267 273 279

257 263 269 274 280

257 263 269 274 280

258 264 270 276 282

160 165 170 175 180

282 287 293 299 305

283 289 294 300 306

283 289 294 300 306

284 290 296 301 307

284 290 296 301 307

285 291 297 303 308

285 291 297 303 308

286 292 298 304 310

286 292 298 304 310

287 293 299 305 311

185 190 195 200 205

311 317 322 328 334

312 318 324 329 335

312 318 324 329 335

313 319 325 331 336

313 319 325 331 336

314 320 326 332 338

314 320 326 332 336

315 321 327 333 339

315 321 327 333 339

317 322 328 334 340

210 215 220 225 230

340 346 351 357 363

341 347 353 358 364

341 347 353 358 364

342 348 354 359 365

342 348 354 359 365

343 349 355 361 366

343 349 355 361 366

344 350 356 362 367

344 350 356 362 367

346 351 357 363 369

235 240 245 250 255

369 374 380 386 391

370 375 381 387 393

370 375 381 387 393

371 377 382 388 394

371 377 382 388 394

372 378 383 389 395

372 378 383 369 395

373 379 385 390 396

373 379 385 390 396

374 380 386 391 397

260 265 270 275 280

397 403 408 414 420

398 404 410 415 421

398 404 410 415 421

399 405 411 416 422

399 405 411 416 422

400 406 412 417 423

400 406 412 417 423

402 407 413 419 424

402 407 413 419 424

403 408 414 420 425

285 290 295 300 305

425 431 437 442 448

426 432 438 443 449

426 432 438 443 449

428 433 439 444 450

428 433 439 444 450

429 434 440 445 451

429 434 440 445 451

430 435 441 447 452

430 435 441 447 452

431 437 442 448 453

310 315 320 325 330

453 459 464 470 475

454 460 466 471 477

454 460 466 471 477

456 461 467 472 478

456 461 467 472 478

457 462 468 473 479

457 462 468 473 479

458 463 469 474 480

458 463 469 474 480

459 464 470 475 481

335 340 345 350

481 487 492 498

482 488 493 499

482 488 493 499

483 489 494 500

483 489 494 500

484 490 495 501

484 490 495 501

485 491 496 502

485 491 496 502

487 492 498 502

227

~ TABLE 6

D 1160

Temperature-Pressure Conversion Table for Petroleum Hydrocarbons (From 6.7 kPa (50 mm Hg)) AET Boiling Point at 101.3 kPa (760 mm Hg) Absolute Pressure

Vapor Temperature

Degrees Celsius 0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

35 40 45 50 55

109 115 121 126 132

110 116 122 128 133

110 116 122 128 133

111 117 123 129 135

111 117 123 129 135

112 118 124 130 136

112 118 124 130 136

113 119 125 131 137

113 119 125 131 137

115 121 126 132 138

60 65 70 75 80

138 144 150 156 162

139 145 151 157 163

139 145 151 157 163

141 146 152 158 164

141 146 152 158 164

142 148 153 159 165

142 148 153 159 165

143 149 155 160 166

143 149 155 160 166

144 150 156 162 167

85 90 95 100 105

167 173 179 185 191

169 174 180 186 192

169 174 180 186 192

170 176 181 187 193

170 176 181 187 193

171 177 183 188 194

171 177 183 188 194

172 178 184 190 195

172 178 184 190 195

173 179 185 191 196

110 115 120 125 130

196 202 208 214 220

198 203 209 215 221

198 203 209 215 221

199 205 210 216 222

199 205 210 216 222

200 206 212 217 223

200 206 212 217 223

201 207 213 218 224

201 207 213 218 224

202 208 214 220 225

135 140 145 150 155

225 231 237 243 248

226 232 238 244 249

226 232 238 244 249

228 233 239 245 251

228 233 239 245 251

229 234 240 246 252

229 234 240 246 252

230 236 241 247 253

230 236 241 247 253

231 237 243 248 254

160 165 170 175 180

254 260 265 271 277

255 261 266 272 278

255 261 266 272 278

256 262 268 273 279

256 262 268 273 279

257 263 269 274 280

257 263 269 274 280

259 264 270 276 281

259 264 270 276 281

260 265 271 277 282

185 190 195 200 205

282 288 294 299 305

283 289 295 300 306

283 289 295 300 306

285 290 296 302 307

285 290 296 302 307

286 291 297 303 308

286 291 297 303 308

287 293 298 304 309

287 293 298 304 309

288 294 299 305 311

210 215 220 225 230

311 316 322 327 333

312 317 323 329 334

312 317 323 329 334

313 318 324 330 335

313 318 324 330 335

314 320 325 331 336

314 320 325 331 336

315 321 326 332 337

315 321 326 332 337

316 322 327 333 339

235 240 245 250 255

339 344 350 355 361

340 345 351 356 362

340 345 351 356 362

341 346 352 358 363

341 346 352 358 363

342 348 353 359 364

342 348 353 359 364

343 349 354 360 365

343 349 354 360 365

344 350 355 361 366

260 265 270 275 280

366 372 377 383 389

368 373 379 384 390

368 373 379 384 390

369 374 380 385 391

369 374 380 385 391

370 375 381 386 392

370 375 381 386 392

371 376 382 387 393

371 376 382 387 393

372 377 383 389 394

285 290 295 300 305

394 400 405 411 416

395 401 406 412 417

395 401 406 412 417

396 402 407 413 418

396 402 407 413 418

397 403 408 414 419

397 403 408 414 419

398 404 409 415 420

398 404 409 415 420

400 405 411 416 421

310 315 320 325 330

421 427 432 438 443

423 428 433 439 444

423 428 433 439 444

424 429 435 440 445

424 429 435 440 445

425 430 436 441 447

425 430 436 441 447

426 431 437 442 448

426 431 437 442 448

427 432 438 443 449

335 340 345 350

449 454 460 465

450 455 461 466

450 455 461 466

451 456 462 467

451 456 462 467

452 457 463 468

452 457 463 468

453 458 464 469

453 458 464 469

454 460 465 470

228

II~) D 1 1 6 0 Digital Temperature Indicator P R T Sensor

~

Option

#2

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Regulating System Cold Trap Option #1

i

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:

I

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I

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i!

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I

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I

I| ,. Insulating Mantle

I, I

Thermowell TO Variac

Heeling Mantle

Circulating

Anti-drip Chain

Pump

Thermo-Regul~ :~r Immersion Heater Coolant Circulating System N O T E - - A cold trap can be inserted before the pressure transducer in Option No, 2, if desired, or if the design of the transducer, such as a mercury McCleod gage, would require vapor protection. FIG, 1 A s s e m b l y of V a c u u m Distillation Apparatus

apparatus must conform to the following requirements. Additional requirements for the automatic apparatus can he found in Annex A9. 6.1.1 Distillation Flask, of 500-mL capacity, made of borosilicate glass or of quartz conforming to the dimensions given in Fig. 2 and having a heating mantle with insulating

receiver as shown in Fig. 4. Alternatively, instead of the metal drip-chain, a metal trough may be used to channel the distillate to the wall of the receiver. This trough may either be attached to the condenser drip tip as shown in Fig. 4 or it may also be located in the neck of the receiver.

top.

NOTE l--There is no simple method to determine the vacuum in the jacket once it is completely sealed. A Tesla coil can be used, but the spark can actually create a pinhole in a weak spot in the jacket. Even the

6.1.2 Vacuum-JacketedColumn Assembly, of borosilicate glass, consisting of a distilling head and an associated condenser section as illustrated in the dimensioned drawing, Fig. 3. The head shall be enclosed in a completely silvered glass vacuum jacket with a permanent vacuum of less than 10 -~ Pa ( 1 0 - 7 m m Hg) (Note 1). The attached condenser section shall be enclosed in water jackets as illustrated and have an adapter at the top for connection to the vacuum source. A light drip-chain shall hang from the drip tip of the condenser to a point 5 mm below the 10-mL mark of the

Distilling Head

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Dimensionsin Millimeters

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Distillation Flask and Heating Mantle

229

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({~) D 1 1 6 0

the jacket is not required.

W,r..oo -/AL

Metal Trough

Condenser Drip-Tip

or Finer

NOTE 2: Precaution--The glass pans of the apparatus are subjected to severe thermal conditions and, to lessen the chances of failure during a test, only equipment shown to be strain-free under polarized light should be used.

6.1.5 Vacuum Gage, capable of measuring absolute pressures with an accuracy of 0.01 kPa in the range below 1 kPa absolute and with an accuracy of 1% above this pressure. The McLeod gage can achieve this accuracy when properly used, but a mercury manometer will permit this accuracy only down to a pressure of about 1 kPa and then only when read with a good cathetometer (an instrument based on a telescope mounted on a vernier scale to determine levels very accurately). An electronic gage such as the Baratron is satisfactory when calibrated from a McLeod gage but must be rechecked periodically as described in Annex A3. A suitable pressure calibration setup is illustrated in Fig. A3.1. Vacuum gages based on hot wires, radiation, or conductivity detectors are not recommended.

,- SmellHole /.',l X */ g~[~,~[ ~..-kt~ forHanging~ ~/" I [~ w'"

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Detail of Drip-Chain or Trough Attachment to Condenser

slightest pinhole or crack not readily detectable by sight alone will negate the vacuum in the jacket.

NOTE 3--Suitable instruments for measuring the pressure of the system during the test are the tensimeter or an electronic pressure gage, provided the output is traceable to a primary gage, such as the non-tilting McLeod gage.

6.1.3 Platinum Resistance Thermometer (PRT) Sensor and associated signal conditioning and processing instruments (Annex A l) for the measurement of the vapor temperature. The system must produce readings with an accuracy of +0.5"C over the range 0 to 400"C and have a response time of less than 200 s as described in Annex A2. The location of the vapor temperature sensor is extremely critical. As shown in Fig. 5, the sensing element must be centered in the neck with the top ofthe sensing tip 3 :t: 1 m m below the spillover point. The sensor shall be preferably mounted through a compression ring type seal mounted on the top of the glass temperature sensor/vacuum adapter. The boiler temperature sensor may be either a thermocouple or P R T and shall also be calibrated as above. 6.1.4 Receiver of borosilicate glass, conforming to the dimensions shown in Fig. 6. If the receiver is part of an automatic unit and is mounted in a thermostatted chamber,

6.1.5.1 Connect the vacuum gage to the side tube of the temperature sensor/vacuum adapter of the distillation column (preferred location) or to the side tube of the sensor/vacuum adapter of the condenser when assembling the apparatus. Connections shall be as short in length as possible and have an inside diameter not less than 8 mm. 6.1.6 Pressure Regulating System, capable of maintaining the pressure of the system constant within 0.01 kPa at pressures of 1 kPa absolute and below and within 1% of the absolute pressure at 1 kPa or higher. Suitable equipment for this purpose is described in Annex A4. Connect the pressure regulating system to the tube at the top of the condenser when assembling the apparatus. Connections shall be as short in length as possible and have an inside diameter not less than 8 m m .

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6.1.12 Coolant Circulating System, capable of supplying coolant to the receiver and condenser system, at a temperature controlled within +3"C in the range between 30 and 80"C. For automatic units where the receiver is mounted in a thermostatted chamber, the coolant circulating system has to be capable of supplying coolant to the condenser system only.

75+_5 t0~$O.D.

MUll be Abova 200 ml Mark

5¢~2

7. Reagents and Materials 7.1 n-Tetradecane--Reagent grade conforming to the specifications of the Committee on Analytical Reagents of the American Chemical Society.6 7.2 ASTM Cetane Reference Fuel (n-Hexadecane), conforming to the specification in Test Method D 613. 7.3 Silicone GreasemHigh vacuum silicone grease specially manufactured for the use in high vacuum applications. 7.4 Silicone Oil, certified by the manufacturer to be applicable for prolonged use at temperatures above 350"C. 7.5 Toluene--Technical grade. 7.6 CyclohexanemTechnical grade.

41±1 $ O D, (Inner Tube) ~

--

51±1 50,D

~ Dimensions In Mllllmeiors

5±3

Note'dlakll IShotrequirefor |utomsU¢ units when receiver Is placedin thermoslltled chamber if Jacketi| used,©¢qlmlcUon|should rml Interferew~thraiding o! gtsdulllons

NoTE---Jacket is not required for automatic units when receiver is placed in thermostatted chamber. If jacket is used, connections should not interfere with

8. Sample and Sampling Requirements 8.1 Sampling shall be done in accordance with Practices D 4057 or D 4177. It is assumed that a 4- to 8-L sample, representative of a shipment or of a plant operation, is received by the laboratory and that this sample is to be used for a series of tests and analyses. An aliquot portion slightly in excess of 200 mL will be required for this test method. 8.2 The aliquot used for this test shall be moisture-free. If there is evidence of moisture (drops on the vessel wall, a liquid layer on the bottom of the container, etc.) use the procedure given in Annex A6, paragraph A6.1, to dehydrate a sufficient quantity of sample to provide the 200-mL charge to the distillation flask. 8.3 Determine the density of the oil sample at the temperature of the receiver by means of a hydrometer by Practice D 1298, by means of a digital density meter by Test Method D 4052, and by using either the mathematical subroutines or tables of Guide D 1250, or a combination thereof. 8.4 If the sample is not to be tested immediately upon receipt, store at ambient temperature or below. If the sample is received in a plastic container, it shall be transferred to a container made out of glass or of metal prior to storage. 8.5 The sample shall be completely liquid before charging. If crystals are visible, the sample shall be heated to a temperature that permits the crystals to dissolve. The sample must then be stirred vigorously for 5 to 15 min, depending on the sample size, viscosity, and other factors, to ensure uniformity. If solids are still visible above 70°C, these particles are probably inorganic in nature and not part of the distillable portion of the sample. Remove most of these solids by filtering or decanting the sample. 8.5.1 There are several substances, such as visbroken

reading of graduations. FIG. 6

Receiver

6.1.7 Vacuum Source, consisting of, for example, one or more vacuum pumps and several surge tanks, capable of maintaining the pressure constant within 1% over the full range of operating pressures. A vacuum adapter is used to connect the source to the top of the condenser (Fig. 1) with tubing of 8 mm ID or larger and as short as practical. A single stage pump of at least 850 L/min (30 cfm) capacity at 100 kPa is suitable as a vacuum source, but a double stage pump of similar or better capacity is recommended if distillations are to be performed below 0.5 kPa. Surge tanks of at least 5 L capacity are recommended to reduce pressure fluctuations. 6.1.8 Cold Traps: 6.1.8.1 Cold trap mounted between the top of the condenser and the vacuum source to recover the light boiling components in the distillate that are not condensed in the condenser section. This trap shall be cooled with a coolant capable of maintaining the temperature of the trap below -40"C. Liquid nitrogen is commonly used for this purpose. NOTE 4: Precaution--If there is a large air leak in the system and liquid nitrogen is used as the coolant, it is possible to condense air (oxygen)in the trap. If hydrocarbons are also present in the trap, a fire or explosion can result when the trap is warmed up in step 10.12. 6.1.8.2 Cold trap mounted between the temperature sensor/vacuum adapter and the vacuum gage to protect the gage from contamination by low boiling components in the distillate. 6.1.9 Low Pressure Air or Carbon Dioxide Source to cool the flask and heater at the end of the distillation. 6.1.10 Low Pressure Nitrogen Source to release the vacuum in the system. 6.1. l I Safety Screen or Safety Enclosure that adequately shields the operator from the distillation apparatus in the event of mishap. Reinforced glass, 6 mm thick clear plexiglass, or a clear material of equivalent strength is recommended.

6 Reagent Chemicals, American Chemical Society Spec:fications, American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed by the American Chemical Society, see Analar Standards for Laboratoo' Chemicals, BDH Ltd., Pools, Dorset, U.K., and the United States Pharmacopeia and National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville, MD.

231

~

D 1160

residues and high melting point waxes, that will not be completely fluid at 70"C. These solids and semi-solids should not be removed since they are part of the hydrocarbon feed.

9. Preparation, Calibration, and Quantification of Apparatus 9.1 Calibrate the temperature sensors and associated signal conditioning and processing device as a unit in accordance with Annex A 1. 9.2 Check the operation of the pressure regulating system as described in Annex A4. 9.3 Clean and dry the glass parts and relubricate the joints. Silicone high-vacuum grease can be used but no more than is necessary to give a uniform film on the ground glass surfaces. An excess of grease can cause leaks and can contribute to foaming at startup. 9.4 Assemble the empty apparatus and conduct a leak test as described in Annex A3, paragraph A3.3.2. 9.5 Check the total apparatus using either of the two reagents described in 7.1 and 7.2 and in accordance with Annex A5.

10. Procedure 10.1 Determine when the temperature sensor was last calibrated. Recalibrate according to Annex A 1 if more time has elapsed than that specified in Annex A 1. 10.2 Set the temperature of the condenser coolant to at least 30"C below the lowest vapor temperature to be observed in the test. NOTE 5--A suitable coolant temperature for distillation of many materials is 60"C. 10.3 From the density of the sample determine the weight, to the nearest 0.1 g, equivalent to 200 mL of the sample at the temperature of the receiver. Weigh this quantity of oil into the distillation flask. 10.4 Lubricate the spherical joints of the distillation apparatus with a suitable grease (Note 6). Make certain that the surfaces of the joints are clean before applying the grease, and use only the minimum quantity required. Connect the flask to the lower spherical joint of the distilling head, place the heater under the flask, put the top mantle in place and connect the rest of the apparatus using spring clamps to secure the joints. NOTE 6--Silicone high-vacuum grease has been used for this purpose. An excess of this lubricant applied to the flaskjoint can cause the sample to foam during distillation. 10.5 Place a few drops of silicone oil in the bottom of the thermowell of the flask and insert the temperature sensor to the bottom. The sensor can be secured with a wad of glass wool at the top of the thermowell. 10.6 Start the vacuum pump and observe the flask contents for signs of foaming. If the sample foams, allow the pressure on the apparatus to increase slightly until the foaming subsides. Apply gentle heat to assist the removal of dissolved gas. For general directions for suppression of excessive foaming of the sample, see Annex A6, Section A6.2. 10.7 Evacuate the apparatus until the pressure reaches the level prescribed for the distillation (Note 7). Failure to reach the distillation pressure, or the presence of a steady increase in pressure in the apparatus with the pump blocked off, is

evidence of significant leakage into the system. Bring the system to atmospheric condition using a. nitrogen bleed and relubricate all joints. If this does not result in a vacuum-tight system, examine other parts of the system for leaks. NOTE 7--The most commonly prescribed pressure is 1.3 kPa (10 mm Hg). For heavy products with a substantial fraction boiling above 500"C, an operating pressure of 0.13 kPa (l mm Hg) or 0.26 kPa (2 mm Hg) is generally specified. 10.8 After the desired pressure level has been attained, turn on the heater and apply heat as rapidly as possible to the flask, without causing undue foaming of the sample. As soon as vapor or refluxing liquid appears at the neck of the flask, adjust the rate of heating so that the distillate is recovered at a uniform rate of 6 to 8 mL/min (Note 8). NOTE 8--It is extremely difficult to achieve the desired rate at the very beginning of the distillation, but this rate should be attainable after the first 10 % of the distillate has been recovered. 10.9 Record the vapor temperature, time, and the pressure at each of the following volume percentage fractions of the charge collected in the receiver: IBP, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 95, and at the end point. If the liquid temperature reaches 400"C, or if the vapor reaches a maximum temperature before the end point is observed, record the vapor temperature reading and the total volume recovered at the time the distillation is discontinued. When a product is tested for conformity with a given specification, record all requested observations, whether or not they are listed above. NOTE 9--The maximum vapor temperature will result either from complete distillation of the oil or from the onset of cracking. 10.10 Ira sudden increase in pressure is observed, coupled with the formation of white vapors and a drop in the vapor temperature, the material being distilled is showing significant cracking. Discontinue the distillation immediately and record the fact on the run sheet. If necessary, rerun the distillation with a fresh sample at lower operating pressure. 10.11 Lower the flask heater 5 to 10 cm and cool the flask and heater with a gentle stream of air or, preferably, with a stream of carbon dioxide (Note 10). Repressure the contents of the still with dry nitrogen (Note 11) if it is necessary to dismantle the apparatus before it has cooled below 200"C. Carbon dioxide can also be used for repressuring, provided liquid nitrogen traps are not in use. NOTE 10--A gentle stream of carbon dioxide is preferred to cool the flask to prevent fire in the event the flask cracks during the test or during the cooling cycle. NOTE I 1: Warning--Repressuring the contents of the still with air while it contains hot oil vapors can result in fire or explosion. NOTE 12: lh'eeaution--In addition to other precautions, it is recommended to discontinue the distillation at a maximum vapor temperature of 350"C. Operating the distillation flask at temperatures above 350"C for prolonged periods at pressures below I kPa may also result in thermal deformation of the flask. In this case, discard the flask after use. Alternatively, use a quartz flask. 10.12 Bring the temperature of the cold trap mounted before the vacuum source back to ambient temperature. Recover, measure, and record the volume of the light products collected in the trap. 10.13 Remove the receiver and replace with another. Remove the flask and replace with another flask filled with a cleaning solvent (Note 13). Run a distillation at atmospheric

232

~

D 1160

TABLE 7 Precision NOTE--The body of this table is in degrees Celsius atmospheric equivalent temperature.

Criteria

Repeatability

Reproducibility

Pressure

0.13 kPa (1 mm Hg)

1.3 kPa (10 mm Hg)

0.13 kPa (1 mm Hg)

1.3 kPa (10 mm Hg)

IBP FBP

17 3.3

15 7.1

56 31

49 27

Volume

5-50 %

60-90 •

5-50 %

60-90 %

0.5 1.0 1.5 2.0 2.5

2.4 2.9 3.2 3.4 3.6

2.5 3.0 3.3 3.5 3.7

1.9 2.4 2.8 3.1 3.3

2.0 2.5 2.9 3.2 3.5

6.5 10 13 16 18

3.9 6.0 7.8 9.4 11

7.0 9.3 11 12 14

5.4 7.2 8.5 9.6 11

3.0 3.5 4.0 4.5 5.0

3.8 3.9 4.0 4.1 4.2

3.9 4.0 4.2 4.3 4.4

3.6 3.8 3.9 4.1 4.3

3.7 3.9 4.1 4.3 4.4

21 23 25 27 29

12 13 15 16 17

15 16 16 17 18

11 12 13 13 14

5.5 6.0 6.5 7.0 7.5

4.3 4.4 4.5 4.6 4.7

4.5 4.6 4.7 4.8 4.8

4,4 4.5 4.7 4.8 4.9

4.6 4,7 4.8 5.0 5.1

30 32 34 35 37

18 19 20 23 22

19 19 20 21 21

15 15 16 16 16

8.0 8.5 9.0 9.5 10.0

4.8 4.8 4.9 5.0 5.0

4.9 5.0 5.1 5.1 5.2

5.0 5.1 5.2 5.3 5.4

5.2 5.3 5.4 5,5 5,6

38 40 41 43 44

23 24 25 25 26

22 22 23 23 24

17 17 18 18 19

10.5 11.0 11.5 12.0 12.5

5.1 5.1 5.2 5.2 5.3

5.2 5.3 5.4 5.4 5.5

5.5 5.6 5.7 5.8 5.9

5.7 5.8 5.9 6,0 6.1

46 47 48 50 51

27 28 29 30 30

24 25 25 26 26

19 19 20 20 20

13.0 13.5 14.0 14.5 15.0

5.3 5.4 5.4 5.5 5,5

5.5 5.6 5.6 5.7 5.7

6.0 6.0 6.1 6.2 6.3

6.2 5.3 6.3 6.4 6.5

52 54 55 56 57

31 32 33 33 34

27 27 27 28 28

21 21 21 22 22

Recovered

5-50 •

60-90 ~

5-50 %

60-90

C/V

pressure to clean the unit. At the end of this cleaning run, remove the flask and receiver and blow a gentle stream of air or nitrogen to dry the unit.

generated from data obtained in a 1983 cooperative interlaboratory program with nine laboratories participating and eight samples being run. In this program, one laboratory used an automatic vacuum distillation analyzer and the results obtained with this equipment have been included in the data used to generate this precision statement. The precision of this test method is as follows: 12.1.1 RepeatabilityNThe difference between two test results, in degrees Celsius, obtained by the same operator with the same apparatus under constant operating conditions on identical test materials would, in the long run, in the normal and correct operation of this test method, exceed the values indicated in Table 7 in only 1 case in 20. 12.1.2 ReproducibilityNThe difference between two single and independent results in degrees Celsius, obtained by different operators working in different laboratories on identical test material would, in the long run, in the normal and correct operation of this test method, exceed the values indicated in Table 7 in only l case in 20. 12.1.3 In Table 7, the rate of change in degrees Celsius (AET) per percentage of liquid volume recovered is shown as C/V%. At any point between the l0 and the 90 % point this value is assumed to be equal to the average value of C/V % of the two data points that bracket the point in question. In no case shall the span of these two points be more than 20 %

NOTE 13--Tolueneor cyclohexanecan be used as cleaningsolvent. 11. Calculations and Report

11.1 Convert the observed vapor temperature readings to Atmospheric Equivalent Temperatures (AET) using Tables 1 through 6 or the equations in Annex A7. In cases of dispute, the equations shall be used. 11.2 Report the AET to the nearest degree Celsius corresponding to the volumetric percentages of liquid recovered in the receiver. Report also the identity of the sample, the density (measured in 8.3), the total amount of liquid distillate recovered in the receiver and in the cold trap before the vacuum source, any unusual occurrence such as foaming or burping, together with the measures that were taken to correct the problem. 12. Precision and Bias 7

12.1 Precision--The precision of this test method was 7 Supporting data are available from ASTM Headquarters. Request RR:D021206.

233

~

D 1160

recovered. An exception is the 5 % point where the span shall be not more than 10 %. See Annex A8 for an example. 12.2 The precision data in Table 7 have been computed from the following equations, which can be used to calculate precision data for C / V % values not listed. 12.2.1 Repeatability (r) can be calculated using the following equation: r = M[e exp{a + b ln(l.8 S)}]/1.8 (1)

0.13 and 1.3 kPa (1 and 10 mm Hg), use constants calculated by linear interpolation from data given in 12.5. l and 12.5.2. 12.4 Bias--Since there is no accepted reference material suitable for determining the bias for the procedure in this test method, no statement is being made. 12.5 Constants for Calculating Table 7: 12.5.1 Constants for calculating repeatability (r): Volume Recovered

where:

At 0.13 kPa (I mm Hg)

- repeatability, *C (AET), = base of natural logarithmic function, approximately 2.718281828, a, b, and M = constants from 12.5.1, and S - r a t e of temperature change (*C, AET) per volume percent recovered. 12.2.2 Reproducibility (R) can be calculated using the following equation: R = M'Ie exp{a' + b' ln(1.8 S)}]/1.8 (2)

a b M a b M

r

e

At 1.3 kPa (10 mm Hg)

IBP

5-50 %

60-95 %

FBP

2.372 0 2.9 2.246 0 2.8

0.439 0.241 2.9 0.240 0.350 2.8

0.439 0.241 3.0 0.240 0.350 2.9

0.718 0 2.9 1.521 0 2.8

12.5.2 Constants for calculating reproducibility (R): Volume Recovered

At 0.13 kPa (I mm Hg)

where: R = reproducibility, *C (AET), a', b', and M' = constants from 12.5.2, and S = rate of temperature change (*C, AET) per volume percent recovered. 12.2.3 See Annex A8 for an example. 12.3 To calculate precision data for pressures between

a' b' M' a' b' M'

At 1.3 kPa (10 mm Hg)

IBP

5-50 %

60-95 %

FBP

3.512 0 3.0 3A24 0 2.9

1.338 0.639 3.3 1.415 0.409 3.2

0.815 0.639 3.3 1.190 0.409 3. I

2.931 0 3.0 2.815 0 2.9

13. Keywords 13. l atmospheric equivalent temperature (AET); boiling range; distillation; vacuum distillation

ANNEXES

(Mandatory Information) A1. PRACTICE FOR CALIBRATION OF TEMPERATURE SENSORS A I. 1 Principle--This section of the Annex deals with the basic calibration of the vapor temperature sensor against primary temperature standards as recommended by the National Institute for Science and Technology (NIST) in order to avoid the problems associated with the use of secondary temperature references. It can also be used for the calibration of other temperature sensors. AI.2 Sensors should be calibrated over the full range of temperatures at the time of first use and whenever the sensor or its associated instrument is repaired or serviced. Sensors used in vapor temperature service should be checked monthly at one or more temperatures. AI.3 Calibrate the sensors with their associated instruments by recording the temperatures of the freezing points of water and of the selected pure metals and metal blends listed in AI.6 under Reagents and Materials. AI.4 Apparatus--A suitable apparatus is shown in Fig. Al.l. For the freezing point of water, a Dewar flask filled with at least 50 % crushed ice in water may be substituted.

Thermowell pl

:.q

I

Pure Grephlte Crucible 25 rnm O . D . x 300 mm Fill to this Level

with Reagent Purity Metal

Standard Dewar Flask $ mm I.D.

b,J

Asbestos Tape

--

Electric Heater 100 W

Wrapping to Make

Crucible Snug Fit Inside Dewar

A 1.5 Procedure: A1.5.1 For sensors that are mounted loosely in a thermowell, place enough silicone oil or other inert liquid in the bottom of the well so as to make good physical contact between the sensor and the tip of the well. Those sensors that are fused into good contact with the tip of the well may be

Metal Foot

FIG. A1.1

234

Melting Point Bath for T e m p e r a t u r e Standards

~

D 1160

calibrated as is. AI.5.2 Place about 0.3 mL of silicone oil in the bottom of the thermowell of the melting point bath and insert the sensors to be calibrated. The oil must cover the tips. A1.5.3 Heat the melting point bath to a temperature 5 to 10*C above the melting point of the metal inside and hold at this temperature for 5 min to ensure that all the metal inside is melted. AI.5.4 Discontinue heat to the melting point bath and observe and record the cooling curve. A paper strip chart recorder is recommended. When the cooling curve shows a plateau of constant temperature for at least 1 min, the temperature of the recorded plateau is accepted as the calibration temperature. A1.5.5 Apply a correction to be added to the reading, if

necessary, to give the correct temperature. A chart may be drawn of correction versus temperature for interpolation. In the case of automated instruments, the correction must be built into the record and must be adjustable. A1.5.6 If the freezing plateau is too short, it can be increased by applying some heat during the cooling cycle. Be aware of the possibility that the metal bath can become contaminated or too oxidized. In this case, replace the metal.

A 1.6 Reagents and Materials: A1.6.1 Distilled Water--Reagent grade as defined by Type III of Specification D 1193, freezing point 0.0*C. A1.6.2 Metals Blend of Sn 50 wt %, Pb 32 wt %, Cd 18 wt %--Freezing point 145.0"C. A1.6.3 Sn--100 %, freezing point 231.9"C. A1.6.4 P b - - 1 0 0 %, freezing point 327.4"C.

A2. PRACTICE FOR D E T E R M I N A T I O N OF T E M P E R A T U R E R E S P O N S E T I M E A2.1 Scope--This practice is for the determination of the temperature response time based on the rate of cooling of the sensor under prescribed conditions. A2.2 Significance and Use--This practice is performed to ensure that the sensor is able to respond sufficiently rapidly to changes in temperature that no significant error due to lag is introduced in a rapidly rising temperature curve. A2.2.1 The importance of this test is greatest under the lowest pressure conditions when the heat content of the vapors is minimal. A2.3 Procedure: A2.3.1 Arrange a I-L beaker of water on a hot plate with a glass thermowell supported vertically in the water. Maintain the temperature of the water at 90 ___5"C. A2.3.2 Connect the sensor to a suitable instrument preferably having a digital readout with a readability to 0. I*C.

Alternatively, connect the sensor to a strip chart recorder of suitable range that will allow interpolation to 0. l*C. Set the chart speed to at least 30 cm/h for ease of reading. A2.3.3 Insert the sensor into a hole in the center of one side of a cardboard cube box of about 30 cm in each dimension. The sensor should be held in place by friction fit of the joint in the hole. Record the temperature in the box when it becomes stable. A2.3.4 Remove the sensor and insert it into the thermowell in the beaker of water. After the sensor has reached a temperature of 80"C, remove it and immediately insert it into the hole in the box. A2.3.5 Observe with a stopwatch, or record on the stripchart, the time interval required by the sensor to cool from 30"C above to 5"C above the temperature recorded in A2.3.3. A2.3.6 A time interval in excess of 200 s is not acceptable.

A3. PRACTICE FOR C A L I B R A T I O N OF V A C U U M GAGES A3.1 Principle--The calibration of vacuum sensors is based upon the use of the McLeod gage, which is the only practical primary gage suitable for this pressure range.

This equation includes the correction term required when the system pressure is an appreciable fraction of the length of the capillary left unfilled with mercury. A requirement for

NOTE A3.l--The general principles of construction of McLeod gages are well-established. The dimensions and tolerances of a gage that, when properly employed, fulfills the requirements of 6.1.5 for the pressure range from 0.1 to 5 kPa are: capillary length of 200 _ 5 mm, capillary diameter of 2.7 mm (known to 0.002 mm), bulk volume + capillary volume, 10.5 4- 0.5 mL (known to 0.05 mL). This gage is best used by adjusting the mercury level in the system pressure arm to a point opposite the closed end of the capillary tube. The system pressure is calculated by means of the following equation:

TO Test Gauges

Ifold 35-40 mm

[

)

P = Kbh2/(V- bh)

I

34/45lr Joint

Oblique Bore 2 mm Stopcock

TO

where: K = 133.32. This is a dimensioned conversion factor to convert m m to N / m 2, P = system pressure, Pa, b = volume of capillary per unit of length expressed as mL/mm, h length of capillary left unfilled by mercury, m m , and V--- combined volume of bulb and capillary, mL.

( Spherical ~ \ Vacuum/

Vacuum Pump

~.~,...--.~=~

Automatic Vacuum

~

~--.-...r~

Drier

(Indicating Ascarite)

~_.

;7

Nitrogen

=

FIG. A3.1 Calibrationof Vacuum Gages 235

~t~ D 1160 NOTE A3.2: Warning--Hg is a poison. Harmful or fatal if inhaled or ingested. A3.3 Procedure: A3.3.1 Set up a test manifold such as that shown in Fig. A3.1. A3.3.2 Ensure that the test manifold is leak-free and can be maintained at a steady pressure at the required level. A suitable leak test is to p u m p down to a pressure below 0.1 kPa and isolate the pump. Observe the pressure inside the unit for at least 1 rain. If the pressure rises no more than 0.01 kPa in that period, the apparatus is considered acceptable. A3.3.3 Connect the primary vacuum gage(s) and the gage(s) to be calibrated. Adjust the pressure to the required level for the test and run a final leak test as above. A3.3.4 Read and record the pressures indicated by all the gages as nearly simultaneously as possible. A3.3.5 Repeat the above procedure at the pressure levels 0.13, 1.3, and 6.7 kPa (l, 10, and 50 m m Hg). A3.3.6 Make up a chart of corrections to be added at each pressure level for each gage tested. This can be used for interpolation when necessary.

the successful operation of this gage to measure system pressures in the range from 100 Pa to 200 Pa (0.75 m m Hg to 1.5 m m Hg) is the determination of the length of capillary left unfilled with mercury with an accuracy of 0.2 ram. At pressures from 0.2 to 2 kPa (1.5 to 15 m m Hg), a precision in this measurement of 0.5 m m is sufficient. A3.2 Apparatus--A suitable test setup is shown in Fig. A3.1. It must be capable of maintaining pressures that are steady within 1% of the required pressure at pressures of 1 kPa and higher and within 0.01 kPa at pressures below 1 kPa. A3.2.1 The McLeod gage, when used as the standard, must have been baked out hot and empty at a pressure below 0.01 kPa before refilling with clean mercury and thereafter be protected from exposure to moisture such as that from atmospheric air. The use of two McLeod gages of different pressure ranges is recommended as a precaution. If they agree at the test pressure, it is an indication that the system is free of moisture and other condensibles.

A4. P R E S S U R E R E G U L A T I N G S Y S T E M A4.1 The following is suggested as a satisfactory example of a pressure regulating system: A low-efficiency, highcapacity vacuum p u m p is connected to one of two surge tanks, each having a capacity of 10 to 20 L and arranged in series. A solenoid valve or other type regulator is installed in the connection between the tanks so that the first tank is maintained at p u m p pressure and the second one at the pressure of the distillation apparatus. A4.1.1 With some apparatus it is desirable to have a slight bleed to the second tank that will cause the controls to operate at regular intervals in order to provide smooth operation. However, experience has shown that the bleed shall be held at an absolute minimum in order to prevent loss of vapors through the manometer connection at the top of the column. A4.1.2 Connecting lines from the second tank to the

vacuum distillation apparatus shall be as short in length and as large in diameter as possible. A minimum internal diameter of 12 m m is suggested. A4.1.3 For multiple still arrangements, it is possible to use a large p u m p and a large low-pressure surge tank. Several smaller tanks operating at the pressures of the various distillations can be attached to the large low-pressure surge tank with individual pressure regulators. Other arrangements can be used, provided the pressure is maintained constant within the limits specified in 6.1.7. NOTE A4. l--If a solenoid valve or other electrically operated regulator is used, a suitable manostat is required for activation of the regulating device. Many such manostats are described in the literature or are available from laboratory supply houses. As an alternative for the separate manostat and solenoid, a Cartesian Manostat can be used. This device is capable of maintaining the system pressure within the specified limits down to a pressure of about 1 kPa.

A5. A P P A R A T U S C H E C K W I T H R E A G E N T FUEL TABLE A5.1

A5.1 Check the assembled apparatus, including the previously calibrated pressure measuring and temperature sensor and associated instrumentation, to indicate proper assembly and operating control. Conduct the test procedure as described at the test pressure in connection with a specific sample or at two or more pressures in connection with general checks of the equipment, using n-hexadecane or n-tetradecane. A5.1. l If n-hexadecane is used, the average of distillation temperatures obtained in the l0 % to 90 % range, inclusive, should conform with the data in Table A5. I. A5.1.2 For pressures over 0.1 kPa not given in Table A5. l, the range of average temperatures shall not deviate by more than 1.5*C from a temperature, t, given by: t = [1831.316/(6.14438 - log P)] - 154.53

Distillation Temperatures of Reference Compounds

Pressure

Range of Temperatures, *C

kPa

mm Hg

0.13 0.67 1.34 2.7 5.3 6.7

1.0 5.0 10.0 20.0 40.0 50.0

n-tetraclecane

n-hexadecane

78.9 to 106.4 to 120.2 to 135.5 to 152.5 to 158.3 to

104.3 to 133.1 to 147.5 to 163.3 to 181.1 to 187.2 to

81.9 109.4 123.2 138.5 155.5 161.3

107.6 136.4 150.8 166.7 184.4 190.6

where P is in kPa, and t is in *C, or t -- [1831.316/(7.01944 - log P)] - 154.53

(A5.2)

where P is in m m Hg, and t is in *C. A5.1.3 If n-tetradecane is used, the average of distillation temperatures obtained in the 10 % to 90 % range, inclusive,

(A5.1) 236

(@) D 1160 t~4 = [1747.452/(6.1471 - log P)] - 168.44

should conform with the data in Table A5.1. A5.1.4 For pressures over 0.1 kPa not given in Table A5.1, and if n-tetradecane is used, the range of average temperatures shall not deviate by more than 1.5"C from a t e m p e r a t u r e , ll4 , given by:

(A5.3)

where P is in kPa, and t is in *C, or t~4 = [1747.452/(7.02216 - log P)] - 168.44

(A5.4)

where P is in mm Hg, and t is in °C.

A6. S A M P L E DEHYDRATION AND FOAMING SUPPRESSION A6.1 Dehydration of Sample--The following is suggested as a convenient means of dehydrating samples to be subjected to this distillation test. Heat 300 mL of the sample to 80"C, add 10 to 15 g of 8- to 12-mesh fused calcium chloride (CaCI2), and stir vigorously for 10 to 15 min. Allow the mixture to cool without stirring, and remove the oil layer by decantation. A6.2 Suppression of Foaming and Bumping of the

steel wool, but do not allow any strand to protrude more than 6 mm into the neck of the flask. Alternatively, take 0.5 to 0.6 g of Grade 2 steel wool, roll into five balls, each approximately 8 to I0 mm in diameter, and drop into the flask. A6.2.4 Boiling Chips--These consist of broken pieces of porcelain drying plates or broken alundum thimbles that are dropped into the flask before starting a distillation. Hengar granules of the plain type, as used in Kjeldahl nitrogen determinations, are also used in the same way (Note A6.1).

Sample: A6.2.1 The tendency of samples to bump or foam excessively is frequently a serious obstacle to the successful distillation of petroleum products under vacuum. In some cases, this is due to the presence of water or dissolved gases, but many samples foam even when apparently free from these contaminants. There is no unanimity of opinion concerning the best way to reduce excessive foaming to manageable proportions. The following methods are offered solely as examples of means that have been employed successfully for that purpose. A6.2.2 DegassingwThe procedure described in 10.6 is intended to promote degassing. Slow rates of pressure reduction or temperature increase, or both, for the oil in the flask are important factors in achieving success by this means. Another technique for degassing is to filter the sample under vacuum before weighing. A6.2.3 Application of Steel Wool--Separate about 10 g of a folded pad of median-grade steel wool. Unfold, and separate into 8 to 10 long, loose strands. Push each strand separately into the bulk of the flask. Avoid packing tightly or forming large void spaces. Fill the upper half of the bulb with

NOTE A6. l - - T h e use of anti-bumping aids can affect the distillation curve. Their use should therefore be limited to cases where they are absolutely needed to perform the distillation.

A6.2.5 Silicone Fluids--The addition of one or two drops of silicone fluid s (350 cSt) to the sample in the flask is effective in the suppression of foam in many cases. However, analytical tests run on the products from this test method can be biased by the presence of these fluids, so the report shall make note of their use. A6.2.6 Flask PreparationmSome laboratories have treated the inside of the flask, prior to use for distillation, in order to provide an active ebullition surface. Methods used for this purpose include: boiling 100 m L of 33 % sodium hydroxide solution for 15 to 20 min, etching of the inside of the flask bottom with hydrofluoric acid fumes, and the infusion of fine carborundum or fritted glass to the inside of the flask bottom. s Dow Coming Silicone Fluid No. 200, available from Dow Coming, has been found satisfactoryfor this purpose.

A7. PRACTICE FOR CONVERTING OBSERVED VAPOR T E M P E R A T U R E S TO A T M O S P H E R I C EQUIVALENT T E M P E R A T U R E S (AET) A7.1 Convert observed temperatures to AET using the following equations: AET = {(748.1 x A)/[I/(VT, K)] + (0.3861 x A) - 0.00051606]} - 273.1 (A7.1) A = {5.143836 - (0.9774472 x log p)}/{2579.33 (A7.2) - (95.76 x log p)}

P

or:

A = {5.9991972 - (0.9774472 x log P)}/{2663.129 - (95.76 x log P)}

where: AET A VT, K *K p

(A7.3)

237

= = = = =

atmospheric equivalent temperature, *C, value obtained in A7.2 or in A7.3, observed vapor temperature, *K, *C + 273.1, pressure of the system, in kPa, observed when the vapor temperature was read, and = pressure of the system, in mm Hg, observed when the vapor temperature was read.

~) D 1160 A8. EXAMPLE OF PRECISION CALCULATIONS A8.1 Procedure." A8.1.1 For a given percentage recovered from a distillation at a given pressure (0.13 or 1.3 kPa), calculate the change in temperature per volume percent recovered {'C(AET)/V % }. A8.1.2 Look up the desired precision (repeatability or reproducibility) from Table 2. Use linear interpolation to find the precision when °C(AET)/V % is not a whole number. A8.2 Example--Desired result: reproducibility of 30 %

recovered, 0.13 kPa (1 mm Hg), *C: AET (*C) 40 % 443 AET (*C) 30 % 427 AET (*C) 20 % 409 *C/V % = (443 - 409)/(40 - 20) = 34/20 = 1.7 From Table 2, Reproducibility, 0.13 kPa (1 mm Hg); recovery between 5 and 50 % (inclusive): *C/V% of 1.5 13 *C/V% of 2.0 = 16 Therefore: 13 + (0.2/0.5)(16- 13)= 14.2, rounded = 14°C. --

A9. DISTILLATION OF PETROLEUM PRODUCTS AT REDUCED PRESSURE (AUTOMATIC) A9.1 ScopemThis test method covers the determination by automatic equipment, at reduced pressures, of the range of boiling points for petroleum products that can be partially or completely vaporized at a maximum liquid temperature of 400"C. A9.2 Summary of Test MethodmThe sample is distilled in an automatic distillation apparatus that duplicates the distillation conditions described in the manual procedure. Data are obtained from which the initial boiling point (IBP), the final boiling point (FBP), and a distillation curve of atmospheric equivalent temperature (AET) versus volume can be obtained. A9.3 Apparatus--The automatic apparatus should be designed to include the components as described in 6.1. Additional parts not specified can be included by the manufacturer that are not essential for obtaining satisfactory results but are desirable components to the assembly for the purpose of promoting efficient use of the apparatus and ease of operation. A9.3.1 Level Follower/Recording Mechanism for the measurement of the volume of liquid recovered in the receiver. The system shall have a resolution of 0. t mL with an accuracy of :t:1 mL. The calibration of the assembly should be confirmed according to the manufacturer's instructions. A9.3.2 Vacuum Gage, capable of measuring the absolute pressure with an accuracy of +10 Pa (+0.08 mm Hg) at 1 kPa (7.5 ram) and below. The vacuum gage is usually an electronic pressure measuring system. An accuracy of :!:1% of the observed reading is required in the range above l kPa. Electronic diaphragm gages are capable of achieving this level of accuracy, but they must be properly calibrated and rechecked periodically, as described in Annex A3. A9.3.3 Receiver Chamber Temperature Control System, capable of controlling the receiver temperature between 32"C and 78"C. A9.4 Sample and Sample Requirements~Sample and sampling requirements are described in Section 8. A9.5 Preparation of Apparatus~The instrument is prepared in accordance with the manufacturer's instructions. A9.6 Procedure: A9.6. l Set the temperature of the condenser coolant to at least 30"C below the lowest vapor temperature to be observed 238

in the test. A temperature near 60"C has been found satisfactory for most charges. A9.6.2 Determine the density of the sample at the temperature of the receiver by means of a hydrometer by Test Method D 1298, by means of a digital density meter using Test Method D 4052, or by using either the mathematical subroutines or tables of Guide D 1250, or a combination thereof. A9.6.3 From the density of the sample, determine the weight, to the nearest 0.1 g, equivalent to 200 mL of the sample at the temperature of the receiver. Weigh this quantity of oil into the distillation flask. A9.6.4 Lubricate the spherical joints of the distillation apparatus with a suitable grease. Connect the flask to the lower spherical joint of the distilling head, place the heater under the flask, put the top mantle in place, and connect the rest of the apparatus using spring clamps to secure the joints. A9.6.5 Insert the temperature sensor into the thermowell of the flask. A9.6.6 Set the operating pressure to the prescribed value for the distillation (see Note 5). The pressure should be automatically reduced in stages to prevent foaming of the sample. A9.6.7 Set the initial heat rate to the desired value. The apparatus should have the capability to adjust heat input so that the distillate recovered is at a uniform rate of 6 to 8 mL/min. A9.6.8 After ensuring that the apparatus controls are set according to the manufacturer's instructions, initiate the distillation. A9.6.9 The apparatus will automatically record the initial boiling point, final boiling point, percent volumes recovered with corresponding actual temperatures, and distillation rates. Actual temperatures recorded are automatically converted to Atmospheric Equivalent Temperatures (AET) using software supplied by the manufacturer. This conversion should be based on Eq (A7.1). A9.6.10 If the liquid temperature reaches 400"C, or if the vapor temperature reaches a maximum before the end point is observed, the distillation equipment shall switch off and terminate the distillation. The apparatus shall automatically record the vapor temperature and total volume percent recovered at the time the distillation is discontinued.

~ A9.6.11 Upon completion of the distillation, the apparatus will automatically enter into a cooling cycle. After the temperature drops below a safe limit, usually 100*C, the pressure in the distillation assembly is gradually increased to atmospheric pressure. The flask and receiver can then be removed for cleaning. If it is necessary to dismantle the apparatus before the contents have cooled below 100*C, use dry nitrogen to bring the system pressure back to atmospheric pressure.

D 1160 A9.6.12 The unit is cleaned as described in 10.13. A9.6.13 Any material in the cold trap is recovered as described in 10.12. A9.7 Precision and Bias: A9.7.1 The precision of the test method using automatic Test Method D 1160 equipment is being determined. A9.7.2 The bias between the manual and the automatic test method is being determined.

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103.

239

~]~

Designation: D 1209 - 93 Standard Test Method for Color of Clear Liquids (Platinum-Cobalt Scale) 1 This standard is issued under the fixed designation D 1209; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (¢) indicates an editorial change since the last revision or reapproval.

This standard has been approvedfor use by agencies of the Department of Defense to replace Method 4243.1 of Federal Test Method Standard No. 141. Consult the DoD Index of Specifications and Standards for the specific year of issue which has been adopted by the Department of Defense.

1. Scope 1.I This test method describes a procedure for the visual measurement of the color of essentially light colored liquids (Note 1). It is applicable only to materials in which the color-producing bodies present have light absorption characteristics nearly identical with those of the platinum-cobalt color standards used. NOTE l mA procedure for estimating color of darker liquids, described for soluble nitrocellulose base solutions, is given in Methods D 365. 1.2 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements see Section 6. 1.3 For specific hazard information, see the Material Safety Data Sheet.

2. Referenced Documents

2. I A S T M Standards." D 156 Test Method for Saybolt Color of Petroleum Products (Saybolt Chromometer Method) 2 D365 Test Methods for Soluble Nitrocellulose Base Solutions 3 D 1193 Specification for Reagent Water 4 D 1209 Test Method for Color of Clear Liquids (PlatinumCobalt Scale) 5 E 180 Practice for Determining the Precision Data of ASTM Methods for Analysis and Testing of Industrial Chemicals 6 E 202 Test Methods for Analysis of Ethylene Glycols and Propylene Glycols6 E 346 Method for Analysis of MethanoP 3. Significance and Use 3.1 The property of color of a solvent varies in imporThis test method is under the jurisdiction of ASTM Committee D-1 on Paint and Related Coatings, Materials, and Applications and is the direct responsibility of Subcommittee D01.35 on Solvents, Plasticizers, and Chemical Intermediates. Current edition approved Sept. 15, 1993. Published November 1993. Originally published as D 1209 - 52. Last previous edition D 1209 - 84 (1988) ~l. 2 Annual Book of ASTM Standards, Vol 05.01. 3 Annual Book of ASTM Standards, Voi 06.02. 4 Annual Book of ASTM Standards, Vols 06.0 i and 11.01. s Annual Book of ASTM Standards, Vol 06.04. 6 Annual Book of ASTM Standards, Vol 15.05.

tance with the application for which it is intended, the amount of color that can be tolerated being dependent on the color characteristics of the material in which it is used. The paint, varnish, and lacquer solvents, or diluents commercially available on today's market normally have little or no color. The presence or absence of color in such material is an indication of the degree of refinement to which the solvent has been subjected or of the cleanliness of the shipping or storage container in which it is handled, or both. 3.2 For a number of years the term "water-white" was considered sufficient as a measurement of solvent color. Several expressions for defining "water-white" gradually appeared and it became evident that a more precise color standard was needed. This was accomplished in 1952 with the adoption of Test Method D 1209 using the platinumcobalt scale. This test method is similar to the description given in Standard Methods for the Examination of Water and Waste Water7 and is referred to by many as "APHA Color." The preparation of these platinum-cobalt color standards was originally described by A. Hazen in the American Chemical Journal8 in which he assigned the number 5 (parts per ten thousand) to his platinum-cobalt stock solution. Subsequently, in their first edition (1905) of Standard Methods for the Examination of Water, the American Public Health Association, using exactly the same concentration of reagents, assigned the color designation 500 (parts per million) which is the same ratio. The parts per million nomenclature is not used since color is not referred directly to a weight relationship. It is therefore recommended that the incorrect term "Hazen Color" should not be used. Also, because it refers primarily to water, the term "APHA Color" is undesirable. The recommended nomenclature for referring to the color of organic liquids is "Platinum-Cobalt Color, Test Method D 1209." 3.3 The petroleum industry uses the Saybolt colorimeter Test Method D 156 for measuring and defining the color of hydrocarbon solvents; however, this system of color measurement is not commonly employed outside of the petroleum industry. It has been reported by various sources that a Saybolt color of +25 is equivalent to 25 in the platinumcobalt system or to colors produced by masses of potassium dichromate ranging between 4.8 and 5.6 mg dissolved in 1 L of distilled water. Because of the differences in the spectral 7 Standard Methods for the Examination of Water and Waste Water, M. Franson, Ed., American Public Health Assoc., 14th ed., 1975, p. 65. s Hazen, A., "New Color Standard for Natural Waters," American Chemical Journal, Vol XIV, 1892, p. 300-310.

240

(~'~ O 1 2 0 9 TABLE 1 Absorbance Tolerance Limits For No. 500 PlatinumCobalt Stock Solution Wavolength, nm

Absorbance

430 455 480 510

0.110to0.120 0.130to0.145 0.105to0.120 0.055 to 0.065

TABLE 2

characteristics of the several color systems being compared and the subjective manner in which the measurements are made, exact equivalencies are difficult to obtain.

Platinum-Cobalt Color Standards

Color Standard Number

Stock Solution, mL

Color Standard Number

Stock Solution, mL

5 10 15 20 25 30 35 40 50 60

1 2 3 4 5 6 7 8 10 12

70 100 150 200 250 300 350 400 450 500

14 20 30 40 50 60 70 80 90 100A

A This is platinum-cobaltcolorNo. 10 In Methods D 365.

4. Apparatus TABLE 3

4.1 Spectrophotometer, equipped for liquid samples and for measurements in the visible region. 9 NOTE 2--The spectrophotometer used must be clean and in firstclass operating condition. The instrument should be calibrated in accordancewith the instructions given in the Standards for Checkingthe Calibration of Spectrophotometers(200 to 1000 nm).'° 4.2 Spectrophotometer Cells, matched having a 10-mm light path. 4.3 Color Comparison Tubes--Matched 100-mL, tallform Nessler tubes, provided with ground-on, optically clear, glass caps. Tubes should be selected so that the height of the 100-mL graduation mark is 275 to 295 mm above the bottom of the tube. 4.4 Color Comparator--A color comparator constructed to permit visual comparison of light transmitted through tall-form, 100-mL Nessler tubes in the direction of their longitudinal axes. The comparator should be constructed so that white light is passed through or reflected offa white glass plate and directed with equal intensity through the tubes, and should be shielded so that no light enters the tubes from the side.l i

Platinum-Cobalt Color Standards for Very Ught Colors

Color Standard Number

Stock Solution, mL

Color Standard Number

Stock Solution, mL

1 2 3 4 5 6 7 8

0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60

9 10 11 12 13 14 15

1.80 2.00 2.20 2.40 2.60 2.80 3.00

5.5 Potassium Chloroplatinate (K2PtCIr). 6. Platinum-Cobalt Reference Standards

6.1 Platinum-Cobalt Stock Solution--Dissolve 1.245 g of potassium chloroplatinate (KzPtCI6) and 1.00 g of cobalt chloride (COC12.6H20) in water. Carefully add 100 mL of hydrochloric acid (HCI, sp gr 1.19) and dilute to 1 L with water. The absorbance of the 500 platinum-cobalt stock solution in a cell having a 10-mm light path, with reagent water in a matched cell as the reference solution,~3 must fall within the limits given in Table 1. 6.2 Platinum-Cobalt Standards--From the stock solution, prepare color standards in accordance with Table 2 by diluting the required volumes to 100 mL with water in the Nessler tubes. Cap the tubes and seal the caps with shellac or a waterproof cement. When properly sealed and stored, these standards are stable for at least 1 year and do not degrade markedly for 2 years) 4 6.2.1 For a more precise measurement of light colors below 15 platinum-cobalt, prepare color standards from the stock solution in accordance with Table 3 by diluting the required volumes to 100 mL with water in the Nessler tubes. Use a semi-microburet for measuring the required amount of stock solution.

5. Reagents

5.1 Purity of Reagents--Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, where such specifications are available) 2 Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination. 5.2 Purity of Water--Unless otherwise indicated, references to water shall be understood to mean reagent water conforming to Type IV of Specification D 1193. 5.3 Cobalt Chloride (CoC12.6H20). 5.4 Hydrochloric Acid (sp gr 1.19)--Concentrated hydrochloric acid (HCI). 9 The Beckman Model B and its equivalents have been found satisfactory for this purpose. ~oSee NIST Letter Circular LC-1017. It A unit available from Scientific Glass and Instruments, inc., P.O. Box 6, Houston, TX 77001, has been found suitable for this purpose. 12 Reagent Chemicals, American Chemical Society Specifications, American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed by the American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville, MD.

241

7. Procedure 7.1 Introduce 100 mL of specimen into a Nessler tube, passing the specimen through a filter if it has any visible turbidity. Cap the tube, place in the comparator, and compare with the standards. ~a See the manufacturer's instruction manual for complete details for operating the spectrophotomcter. ~4Scharf, W. W., Ferber, K. H., and White, R. O., "Stability of PlatinumCobalt Color Standards," Materials Research and Standards, Vol 6, No. 6, June 1966, pp. 302-304.

t ~ D 1209 8. Report 8.1 Report as the color the number of the standard that most nearly matches the specimen. In the event that the color lies midway between two standards, report the darker of the two. 8.2 If, owing to differences in hue between the specimen and the standards, a definite match cannot be obtained, report the range over which an apparent match is obtained, and report the material as "off-hue."

9. Precision's 9.1 Color Standards: 9.1.1 These precision statements are based upon an interlaboratory study in which five platinum-cobalt standards having values of 25, 75, 170, 385, and 475 were prepared in accordance with the instructions given in Section 6 of this test method and were given coded labels. These solutions were tested by one analyst in each of ten different laboratories making a single observation on one day and then repeating the observation on a second day. The analysts were requested to estimate the color to the nearest one unit for solutions below 40 platinum-cobalt, to the nearest five units for solutions between 40 and 100 platinum-cobalt and to the nearest ten units for solutions above 100 platinumcobalt. In this interlaboratory study, the within-laboratory coefficient of variation was found to be 1.8 % with 60 df, and the between-laboratories coefficient of variation was found to be 5.3 % with 54 dr. Based on these results, the following criteria, calculated in accordance with Practice E 180, should be used for judging the acceptability of results at the 95 % confidence level when the results are obtained under o13-

timum conditions where the hue of the sample matches exactly the hue of the standards. Poorer precision ~II obtained in varying degrees as the hue of the sample departs from that of the standards. 9. I. 1.1 Repeatability--Two results, obtained by the same analyst on different days, should be considered suspect if they differ by more than 5.1%. 9.1.1.2 ReproducibilitywTwo results, obtained by analysts in different laboratories, should be considered suspect if they differ by more than 15 %. 9.2 Specimen: 'e 10.2.1 In an interlaboratory study of this test method in which the standards described in Table 3 were used, the within-laboratory standard deviation was found to be one platinum-cobalt unit at 56 df and the between-laboratory standard deviation was found to be 2 platinum-cobalt units at 25 df. Based on these standard deviations, the following criteria should be used for judging, at the 95 % confidence level, the acceptability of results obtained on light colored samples. 9.2.1.1 Repeatability--Two results, each the mean of duplicates, obtained by the same operator on different days should be considered suspect if they differ by more than two platinum-cobalt units. 9.2.1.2 Reproducibility---Two results, each the mean of duplicates, obtained by operators in different laboratories should be considered suspect if they differ by more than seven platinum-cobalt units.

10. Keywords 10.1 clear liquids; color; platinum-cobalt color scale ,6 These precision statements are based on intedaboratory studies conducted by Committee E-15 on Industrial Chemicals on samples of ethylene glycol and methanol as reported in Method E 202, Method E 346, and research report RR: EI5-28.

's Supporting data are available from ASTM Headquarters. Request RR: D01-1024,

The American Society for Testing and Materials takes no position respecting the vahdlty of any patent rights asserted in connection with any item mentioned in this standard Users of this standard are expressly advised that determJnahon of the validity of any such patent rights, and the risk of mfnngement of such rights, are entirely their own responsibility This standard is Sublect to revision at any time by the responsible techmcel committee and must be reviewed every hve years and if not rev/sed, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters Your comments will receive careful consideration at a meetmg of the responsible technical committee, which you may attend If you feel that your comments have not received a fair heaong you should make your views known to the ASTM Committee on Standards, 100 Barr Harbor Drwe, West Conshohocken, PA 19428.

242

Designation: D 1218 - 92

An American National Standard

Standard Test Method for Refractive Index and Refractive Dispersion of Hydrocarbon Liquids 1 This standard is issued under the fixed designation D 1218; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (~) indicates an editorial change since the last revision or reapproval.

1. Scope 1.1 This test method covers the measurement of refractive indexes, accurate to six units in the fifth decimal place, and refractive dispersions, accurate to twelye units in the fifth decimal place, of transparent and light-colored hydrocarbon liquids that have refractive indexes in the range from 1.33 to 1.50, and at temperatures from 20 to 30"C. The test method is not applicable within the accuracy stated to liquids having colors darker than No. 4 ASTM Color as determined by Test Method D 1500, to liquids having bubble points so near the test temperature that a reading cannot be obtained before substantial weathering takes place, to liquids having a refractive index above 1.50, or to measurements made at temperatures above 30"C.

refraction, as light passes from air into the substance. This is the relative index of refraction. If absolute refractive index (that is, referred to vacuum) is desired, this value should be multiplied by the factor 1.00027, the absolute refractive index of air. The numerical value of refractive index of liquids varies inversely with both wavelength and temperature. 3.1.2 refractive dispersion--the difference between the refractive indexes of a substance for light of two different wavelengths, both indexes being measured at the same temperature. For convenience in calculations, the value of the difference thus obtained is usually multiplied by 10,000.

4. Summary of Test Method

NOTE l--The instrument can be successfully used for refractive indexes above 1.50, and at temperatures both below 20"C and above 30°C, but as yet certified liquid standards for the ranges above a refractive index of 1.50 are not available,so the precision and accuracy of the instrument under these conditions have not been evaluated. Similarly, certified refractive indexes of liquids at temperatures other than the 20 to 30"Crange are not available,althoughthe instrument can be used up to 50"C.

4.1 The refractive index is measured by the critical angle method with a Bausch & Lomb Precision Refractometer using monochromatic light. The instrument is previously adjusted by means of a solid reference standard and the observed values are corrected, when necessary, by a calibration obtained with certified liquid standards.

1.2 This standard does not purport to address all of the

5.1 Refractive index and refractive dispersion are fundamental physical properties which can he used in conjunction with other properties to characterize pure hydrocarbons and their mixtures.

5. Significance and Use

safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 2. Referenced Documents

2.1 A S T M Standards: D 841 Specification for Nitration Grade Toluene 2 D 1500 Test Method for ASTM Color of Petroleum Products (ASTM Color Scale)3 E 1 Specification for ASTM Thermometers 4

3. Terminology 3.1 Definitions: 3. I. 1 refractive index--the ratio of the velocity of light (of specified wavelength) in air, to its velocity in the substance under examination. It may also be defined as the sine of the angle of incidence divided by the sine of the angle of This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D 02.04 on Hydrocarbon Analysis. Current edition approved Aug. 15, 1992. Published October 1992. Originally published as D 1218 - 52 T. Last previous edition D 1218 - 87. 2 Annual Book of ASTM Standards, Vol 06.04. 3 Annual Book ofASTM Slandards, Vol 05.01. 4 Annual Book of ASTM Standards, Vol 14.03.

6. Apparatus 6.1 Refractometer, Bausch & Lomb, "Precision" type, 5 range 1.33 to 1.64 for the sodium D line. 6.2 Thermostat and Circulating Pump, capable of maintaining the indicated prism temperature constant within 0.02"C of the desired test temperature. The thermostating liquid should pass the thermometer on leaving, not on entering, the prism assembly. 6.3 Thermometer--ASTM Saybolt Viscosity Thermometer 17C having a range from 19 to 27"C, and conforming to the requirements of Specification E I. The thermometer shall be used in an approved holder, as shown in Fig. 1, such that almost total immersion (not more than emergent stem) is obtained, and reading to 0.01*C is possible. 6.4 Light Sources--The following light sources have been found satisfactory: s Manufactured by Bausch & Lomb Optical Co., Rochester, NY, Catalog No. 33-45-03. All instrument terminology used in this method corresponds with that used in the "Reference Manual" supplied with the instrument. Production &this refractometer was discontinued in 1976. However it may be obtainable from instrument exchanges or used equipment suppliers. If other available instrumentation is used, the precision statements of Section 13 will not apply.

243

~

D 1218 7. Solvents

7.1 n-Pentane, 95 mol % minimum purity. NOTE 3: Warning--Extremely flammable. Harmful if inhaled. Vapors may cause flash fire. 7.2 Toluene, conforming to Specification D 841. NOTE 4: Warning--Flammable. Vapor harmful. 8. Reference Standards

8.1 Solid Reference Standard, accurate to +0.00002 with ther value of the refractive index engraved upon its upper face. 8.2 PrimaryLiquid Standards--The organic liquids listed below, with the values of their refractive indexes for the D, F, and C lines certified at 20, 25, and 30°C, obtained from the API Standard Reference Office:6 2,2,4-Tdmethylpcntane Methyleyelohexane Toluene

nD = 1.39 no = 1.42 no = 1.49

NOTE 5: Warning--Flammable.

FIG. 1

Thermometer Holder

6.4.1 Sodium Arc Lamp---The Unitized "Sodium Lab Arc" is furnished with the instrument. 6.4.2 Mercury Arc Lamp--The H-4 type capillary mercury arc is furnished as an accessory to the refractometer. 6.4.3 Hydrogen Discharge Lamp--Any type of lamp capable of producing light having an intensity of at least 32 Ix (3 footcandles) on an area of I cm 2 on the entrance face of the illuminating prism. The luminous intensity may be conveniently measured by means of a photographic light meter held 254 mm (10 in.) from the lamp and perpendicular to the light beam. For convenience, the lamp should be mounted on an extension of the sodium lamp support. 6.4.4 Other Sources--Helium may be used in place of hydrogen in the lamp discussed in 6.4.3. 6.4.5 Light Filters--For isolating the various spectral lines from the above sources, special light filters are required. The following are tentatively recommended: Wave-length. A

Spectral Line

Filter

6678 6563 5893 5461

Helium H,. Na o Hg,.

5016 4861

Helium H~

4358

Hgx

Corning No. 2404 None required, May use Coming No. 2404. None required Wratten No. 62, or No. 77A, Coming Nos. 3486 + 4303 + 5120 Wratten No. 45 Coming Nos. 5030 + 3387, 4303, or Wratten No. 45 Coming Nos. 5113, 3389 + 5850.

NOTE 2--1n determinations of refractive indexes above approximately 1.53 (wherever the short wavelengths show a higher scale reading than the long) this system o f filters is rendered worthless and filters must be chosen which remove all spectral lines o f shorter wavelength than the o n e being read. Below this refractive index, the specific filters listed above, which remove spectral lines o f longer wavelengths than the one being read, should be used.

9. Sample 9.1 A sample of at least 0.5 mL is required. The sample shall be free of suspended solids, water, or other materials that tend to scatter light. Water can be removed from hydrocarbons by treatment with calcium chloride followed by filtering or centrifuging to remove the desiccant. The possibility of changing the composition of a sample by action of the drying agent, by selective adsorption 'on the filter, or by fractional evaporation, shall be considered. NOTE 6: Warning--Volatile hydrocarbonsamples are flammable. I0. Preparation of Apparatus 10.1 The refractometer shall be kept scrupulously clean at all times. Dust and oil if allowed to accumulate on any part of the instrument will find their way into the moving parts, causing wear and eventual misalignment; if permitted to collect on the prism, dust will dull the polish, resulting in hazy lines. 10.2 Thoroughly clean the prism faces with a swab of surgical-grade absorbent cotton saturated with a suitable solvent such as toluene. Pass the swab very lightly over the surface until it shows no tendency to streak. Repeat this procedure with n-pentane until both the glass and the adjacent polished metal surfaces are clean. Do not dry the prism faces by rubbing with dry cotton. I0.3 Adjust the thermostat so that the temperature indicated by the refractometer thermometer is within 0.02"C of the desired value; turn on the sodium vapor lamp and allow it to warm up 30 min. NOTE 7--An error of 0.02"C in temperature of the sample will cause an error of I × 10-s in the refractiveindex of methylcyclohexane. 10.4 Control the ambient temperature within I°C of the test temperature. This can be done by regulation of the room temperature or by placing the instrument inside a specially designed constant-temperature box. The instrument shall also be so situated that it will not be subject to drafts. 6 Carnegie-Mellon University, Pittsburgh, PA.

244

t~ D 1218 11. Standardization of Apparatus and Technique 11.1 Thoroughly clean the prism faces and surfaces of the solid reference standard as described in 10.2, finally brushing the surfaces with a clean camel's-hair brush. Fix the hinged part in a wide-open position. Apply a drop of monobromonaphthalene, about 1.5 mm in diameter, to the center of the polished surface of the reference standard. Press the reference standard against the surface of the stationary prism with the polished end toward the light. If the proper amount of contacting liquid has been used, a continuous film of liquid will form between the prism and the reference standard, and the field will appear evenly illuminated. I f not, irregular dark spots will appear in the illuminated field of the telescope when the knurled knob is turned and the light is in line with the longitudinal axis of the telescope. Gently manipulate the reference standard by pressure on one edge or another until the interference bands, as seen with the aid of the auxiliary lens, appear to extend horizontally in the rectangular contact area. It is well to keep the liquid wedge at such an angle that three to five bands can be seen, and the fringe pattern should appear centered in the exit pupil of the telescope. NOTE 8--If there is any trace of roughness as the contact is being made, remove the referencestandard and clean all surfaces again. More damage can be done to the prism surface in this operation than in weeks of use with liquids, if grit comes between the two surfaces during this contact. The amount of liquid should be just enough to fill the contact area completely, leaving no liquid at the front edge of the reference standard. 11.2 Set the instrument to the scale reading corresponding to the refractive index engraved on the solid reference standard. Rotate the sodium lamp base while viewing the telescope until a sharp vertical line appears in the illuminated field and does not move with the rotation of the lamp. Adjust the eyepiece of the telescope to bring the cross hairs into sharp focus. 11.3 Move the alidade by means of the hand wheel until the critical line on the left side of the band intersects the cross hairs, and read the scale. Repeat the setting at least twice and, between settings, shift the lamp slightly while observing the critical line in order to make sure a false line is not being observed. Average the scale readings for all the settings. 11.4 Convert the average scale reading to refractive index by means of the table for the sodium D line. To give correct readings, without application of corrections, the average value obtained may differ from that engraved on the test specimen by more than 0.00002. 11.5 If adjustment is necessary, set the scale to the reading corresponding to the value engraved on the solid reference standard, by means of the hand wheel on the side of the instrument. If the critical line is to the left of the intersection of the cross hairs, loosen the small screw on the left of the telescope and slowly tighten the one on the right until the lines coincide; if the critical line is to the right of the intersection, use the opposite procedure. At the final adjustment both screws should be snug but not tight. Again check the setting as in 11.3. 12. Standardization with Reference Liquids

12.1 Measure the refractive indexes ofeach of the primary liquid standards listed in 8.2 for the D, F, and C lines, at the test temperature 20, 25, or 30"C, following the procedure

described in Section 13. If the values obtained do not agree with the certified values within 0.00003, determine a correction curve for each wavelength from an average of five independent determinations on each of the three certified liquid standards. A plot of the average error against refractive index provides a correction for all observed indexes between these points. NOTE 9--This does not imply that the refractive index engraved on the test specimen is necessarilyinaccurate, but tends to correct an error introduced in the determination by the failure to obtain grazing incidence in the case of liquid samples. This fault, and other instrumental errors, if present, are inherent in the refractometer design and their magnitude varies with the refractive index of the liquid and different instruments. 12.2 To observe any changes with time and use in the relative positions of prism and alidade, each operator shall check the instrument with the calibrated solid reference standard prior to his use of the instrument. 13. Procedure

13.1 Thoroughly clean the prism faces as described in 10.2. Adjust the thermostat so that the temperature indicated by the refractometer thermometer is within 0.02"C of the desired value. 13.2 In testing nonviscous liquid samples, close the prism box and let stand for 4 to 5 rain to ensure temperature equilibrium between the prisms and the circulating water. By means of a small pipet or medicine dropper, introduce a small quantity of sample into the tubulation between the prism faces. Turn the knurled head at the base of the telescope so as to bring the auxiliary lens into the light path, and observe through the face of the working prism. If the space between the prisms is completely filled with liquid, the field will be uniformly illuminated; bubbles or unfilled spaces will appear black. If the space is not completely filled, open the prism box slightly several times and add more liquid. Do not attempt to measure refractive indexes until the space between the prisms is completely filled. 13.3 In testing viscous liquids, open the prism box and apply the sample to the faces of both prisms, spreading evenly with a round wooden applicator stick. Never use metal or glass for this purpose as these may scratch the prism faces. Close the prism box slowly to avoid straining the hinge and locking mechanism. 13.4 Adjust the illuminant to be in line with the telescope and bring the border line approximately to the reticle. While viewing the rear prism face by means of the auxiliary lens, rotate the lamp bracket to the right until only the extreme left side of the prism appears to be illuminated. If this rotation is carded too far, vertical interference lines will appear in the back face. These are generally irregular and rather faint. The best adjustment for contrast and illumination seems to be the point just before these fringes become distinct. 13.5 Adjust the eyepiece of the telescope so as to bring the cross hairs into sharp focus, set the cross hairs on the critical edge and read the scale of the instrument. Readjust the position of the vapor lamp and repeat at least four times, approaching from either side of the critical edge, and record the average scale reading. (In order to avoid the possibility of using a false edge, it is best to adjust the position of the light 245

~) D 1218 15. Precision and Bias 15.1 Results should not differ from the mean by more than the following amounts:

source each time a setting is made rather than make four settings on one positioning of the lamp.) 13.6 Without changing the position of the prism assembly, place other desired light sources into the angular position (with respect to the rear face of the refracting prism) occupied by the sodium lamp. Take average scale readings for the desired lines in the manner described in 13.4. 13.7 In testing volatile samples, clean the prism faces without changing the position of the prism assembly or the lamp, recharge with sample, and read immediately.

Refractive index Refractive dispersion

Repeatability One Operator and Apparatus 0.00006 0.00012

Reproducibility Different Opera. tots and Apparatus 0.00006 0.00012

15.2 Bias--The difference of results from the established value when compared to pure reference materials is not expected to be more than. Refractive Index ± 0.00006 Refractive Dispersion ± 0.00012 15.2.1 Specific bias has not been established by cooperative testing. 15.3 The precision of this test method was not obtained in accordance with Research Report RR: D-2-1007, "Manual on Determining Precision Data for ASTM Methods on Petroleum Products and Lubricants. "7

14. Calculation and Report 14.1 Convert the observed scale readings to refractive indexes by use of the tables supplied with the instrument and report these values and the temperature at which the test was made, distinguishing between the various spectral lines used (for example, "no = 1.- ." or "n5 s t 9 3 = 1 . . . " ) . 14.2 To obtain refractive dispersion, subtract, nx2 and nx,. Report the result and the temperature at which the test was made (for example "(nl..- no) x 104 at t . . . . " o r "(n~ - riD) X 104 at t . . . . ").

16. Keywords 16.1 hydrocarbons; refractive dispersion; refractive index; refractometer 7 Annual Book of ASTM Standards, Vol 05.03.

The American Society for Testing and Materials takes no position respecting the vahd~ty of any patent r~ghts asserted m connection with any item mentioned in this standard Users of this standard are expressly adwsed that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is Sublect to rewston at any time by the responsible technical committee and must be reviewed every hve years and ff not revised, either reapproved or withdrawn. Your comments are mwted either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters Your comments wtfl receive careful consideration at a meeting of the responsible technical committee, which you may attend If you feel that your comments have not received a fair hearing you should make your wews known to the ASTM Committee on Standards, 100 Barr Harbor Drive, West Conshohocken, PA 19428.

246

Designation: D 1250 - 80 (Reapproved 1997) °

An Amedcen National Standard BSI Handbook

Standard: API MPMS Ch.11.1

Designation: 200/80 (90)

Standard Guide for Petroleum M e a s u r e m e n t Tables 1 The following text is a description of the Petroleum Measurement Tables which comprise Chapter 11, Section 1, of the API Manual

of Petroleum Measurement Standards (MPMS) and which are distributed in three base systems of measurement: "API, "F, 60"F; relative density, "F, 60"F; and kilogram per cubic metre, "C, 15"(2. This guide has been approved by the sponsoring committees and accepted by the cooperating organizations in accordance with established procedures. This guide has been adoptedfor use by government agencies to replace Method 9004.1 of Federal Test Method Standard No. 791b. e~ NcyrE--Section 6 was added editorially in October 1997.

distributed subroutines are the secondary standard, and the published tables are produced for convenience.

1. Scope 1.1 These Petroleum Measurement Tables2 are for use in the calculation of quantities of crude petroleum and petroleum products at reference conditions in any of three widely used systems of measurement. These tables are provided for standardized calculation of measured quantities of petroleum fluids regardless of point of origin, destination, or units of measure used by custom or statute. 1.2 The Petroleum Measurement Tables published in 1980, except for Tables 33 and 34 (which are being reissued without change), represent a major conceptual departure from previous versions. Inherent in the Petroleum Measurement Tables is the recognition of the present and future position of computers in the petroleum industry. The actual standard represented by the Petroleum Measurement Tables is neither the hardcopy printed tables nor the set of equations used to represent the density data but is an explicit implementation procedure used to develop computer subroutines for Tables 5, 6, 23, 24, 53, and 54. The standardization of an implementation procedure implies the standardization of the set of mathematical expressions, including calculational sequence and rounding procedures, used within the computer code. Absolute adherence to the outlined procedures will ensure that all computers and computer codes of the future, meeting the stated specifications and restrictions, will be able to produce identical results. Hence, the published implementation procedures are the primary standard, the

NOTE l - - T h e present collection o f tables supersedes all previous editions o f the Petroleum M e a s u r e m e n t Tables A N S I / A S T M D 1250, IP 200, a n d API Standard 2540.

2. Referenced Document 2.1 A S T M Standard:

D 287 Test Method for API Gravity of Crude Petroleum and Petroleum Products (Hydrometer Method) 3 3. Sponsorship 3.1 The complete collection of the new jointly issued ASTM-API-IP tables is the result of close cooperation between the American Society for Testing and Materials, American Petroleum Institute, and the Institute of Petroleum (London). To meet the objective of worldwide standardized measurement practices, the American National Standards Institute and the British Standards Institution have also been closely involved, resulting in the acceptance of the revised tables as an American National Standard and a British Standard. In addition, in their respective capacities as Secretariat of the International Organization for Standardization/TC 28 and of TC 28/SC 3, ANSI and BSI have been instrumental in progressing the revised tables toward their adoption as an International Standard by the International Organization for Standardization. The ASTM Designation D 1250 applies to all 35 tables described in Section 5. The Institute of Petroleum designation for the complete set of tables is 200/8 I.

: This guide is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct respousibility of Subcommittee 1302.02 on Static Petroleum Measurement. Current edition approved Sept. 19, 1980. Published November 1980. Originally published as D 1250 - 52 T, replacing former D 206 and D 1090. Last previous edition D 1250 - 56 (1977). 2 When ordering from ASTM, 1916 Race St., Philadelphia, Pa. 19103, request PCN 12-412508-01, for Vol 1; PCN 12-412508-02, for Vol lI; PCN 12-412508-03, for Vol III; PCN 12-412508-04, for Vol IV; PCN 12-412508-05, for Vol V; PCN 12-412508-06, for Vol VI; PCN 12-412508-07, for Vol VII; PCN 12-412508-08, for Vol VIII; PCN 12-412508-09, for Vol IX; PCN 12-412508-10, for Vol X; and for Vol XI/XII; PCN 12-4125 08-1 I.

4. Significance and Use 4.1 This guide is expected to apply to crude petroleum regardless of source and to all normally liquid petroleum products derived therefrom. There are three primary sets of tables in current use. These are in terms of *API (Tables 5 aAnnual Book of ASTM Standards, Vol 05.01.

247

~]~ D 1250 Volume III: Table 6C--Volume Correction Factors for Individual and Special Applications, Volume Correction to 60*F Against Thermal Expansion Coefficients at 60*F Volume IV: Table 23A--Genera~ed Crude Oils, Correction of Observed Relative Density to Relative Density 60/60"F Table 24A--Generalized Crude Oils, Correction of Volume to 60*F Against Relative Density 60/60"F Volume V: Table 23B---Generalized Products, Correction of Observed Relative Density to Relative Density 60/60"F Table 24B--Generalized Products, Correction of Volume to 60*F Against Relative Density 60/60"F Volume VI: Table 24C--Volume Correction Factors for Individual and Special Applications, Volume Correction to 60*F Against Thermal Expansion Coefficients at 60*F Volume VII: Table 53A--Generalized Crude Oils, Correction of Observed Density to Density at 15"C Table 54A--Generafized Crude Oils, Correction of Volume to 15"C Against Density at 15"C Volume VIII: Table 53B---Generalized Products, Correction of Observed Density to Density at 15"C Table 54B-.Generalized Products, Correction of Volume to 15"C Against Density at 15"C Volume IX: Table 54C--Volume Correction Factors for Individual and Special Applications, Volume Correction to 15"C Against Thermal Expansion Coefficients at 15"(2 Volume X: Background, Development, and Implementation Procedures Volumes XI and XI1: Tables 2, 3, 4, 8, 9, 10, 11, 12, 13, 14, 21, 22, 26, 27, 28, 29, 30, 3 I, 51, 52, and 58 Reissued Without Change: Table 33--Specific Gravity Reduction to 60*F for Liquefied Petroleum Gases and Natural Gas Table 34--Reduction of Volume to 60*F Against Specific Gravity 60/60"F for Liquefied Petroleum Gases

and 6), relative density (Tables 23 and 24), and density in kilogram per cubic metre (Tables 53 and 54). To maximize accuracy and maintain convenience of use in primary tables (Tables 5, 6, 23, 24, 53, and 54), crude oils and products are presented in separate tables. For example, for Table 6 there are: Table 6A, Generalized Crude Oils; Table 6B, Generalized Products; and Table 6C, Volume Correction Factors for Individual and Special Applications. The subsidiary tables are based on averages of the crude oil and product volume correction factors obtained from the primary tables and, hence are not included in the precision statement that encompass the primary tables. 4.2 The ranges for the primary tables are as follows: Table A

Table B

"API

"F

"API

"F

0 to 40 40 to 50 50 to 100

0 to 300 0 to 250 0 to 200

0 to 40 40 to 50 50 to 85

0 to 300 0 to 250 0 to 200

Table C a ~

"F

270 to 510 × 10-6 510 to 530 530 to 930

0 to 300 0 to 250 0 to 200

A Alpha is the eoettieient of thermal expansion at 60"F.

The ranges of the subsidiary tables, except Tables 33 and 34, encompass the range of Table A. 4.3 All tables that involve reduction of gravity to standard temperature are based on the assumption that the measurement has been made by means of a glass hydrometer (Test Method D 287), and that correction for the thermal expansion of standard hydrometer glass has been incorporated. To accommodate the growing use of on-line densitometers, which are not dependent on hydrometer corrections, the computer subroutines optionally allow for the exclusion of the hydrometer correction. 5. Available Tables Volume I: Table 5A---Generalized Crude Oils, Correction of Observed API Gravity to API Gravity at 60*F Table 6A--Generalized Crude Oils, Correction of Volume to 60*F Against API Gravity at 60*F Volume 11." Table 5B--Generalized Products, Correction of Observed API Gravity to API Gravity at 60*F Table 6B--Generalized Products, Correction of Volume to 60*F Against API Gravity at 60*F

6. Keywords 6.1 density; gravity; hydrometer; temperature; volume correction

The American Soc/aty for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of Infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and ff not revised, either reepproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend, ff you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 100 Barr Harbor Drive, West Conshohockan, PA 19428.

248

Designation: D 1265 - 92

An American National Standard

Standard Practice for Sampling Liquefied Petroleum (LP) Gases (Manual Method) 1 This standard is issued under the fixed designation D 1265; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reappmval. A superscript epsilon (~) indicates an editorial change since the last revision or reapproval.

I. Scope I.I This practice covers the procedures for obtaining representative samples of liquefied petroleum gases such as propane, butane, or mixtures thereof, in containers other than those used in laboratory testing apparatus. These procedures are considered adequate for obtaining representative samples for all routine tests for LP gases required by Specification D 1835 except analysis by Test Method D 2163. They are not intended for obtaining samples to be used for compositional analysis. A sample procedure that avoids changes in composition must be used for compositional analysis. NOTE l--Practiee D 3700 describes a recommended method for obtaining a representative sample of a hydrocarbon fluid and the subsequent preparationof that sample for laboratoryanalysis. 1.2 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applica. bility of regulatory limitations prior to use.

2. Referenced Documents 2.1 A S T M Standards: D 1835 Specification for Liquefied Petroleum (LP) Gases2 D 2163 Test Method for Analysis of Liquefied Petroleum (LP) Gases and Propene Concentrates by Gas Chromatography3 D 3700 Practice for Containing Hydrocarbon Fluid Samples Using a Floating Piston Cylinder4 3. Summary of Practice 3.1 A liquid sample is transferred from the source into a sample container by purging the container and fdling it with liquid, then providing 20 % outage so that 80 % of the liquid volume remains.

5. General Information 5.1 Considerable effort is required to obtain a representative sample, especially if the material being sampled is a mixture of liquefied petroleum gases. The following factors must be considered: 5.1.1 Obtain samples of the liquid phase only. 5.1.2 When it is definitely known that the material being sampled is composed predominantly of only one liquefied petroleum gas, a liquid sample may be taken from any part of the vessel. 5.1.3 W h e n the material being sampled has been agitated until uniformity is assured, a liquid sample may be taken from any part of the vessel. 5.1.4 Because of wide variation in the construction details of containers for liquefied petroleum gases, it is difficultto specify a uniform method for obtaining representative samples of heterogeneous mixtures. If it is not practicable to agitate a mixture for homogeneity, obtain liquid samples by a procedure which has been agreed upon by the contracting parties. 5.1.5 Directions for sampling cannot be made explicit enough to cover all cases. Tbey must be supplemented by judgment, skill,and sampling experience. Extreme care and good judgment are necessary to ensure samples which represent the general character and average condition of the material. Because of the hazards involved, liquefied petroleum gases should be sampled by, or under the supervision of, persons familiarwith the necessary safety precautions. NOTE 2--Samplesto be testedforpresenceof corrosivecompounds or sulfur compounds should be taken in stainless steel containers equipped with stainless steel valves; otherwise, determinations of mercaptansand hydrogensulfide,for example,can be misleading. 5.1.6 Hydrocarbon vapors vented during sampling must be controlled to assure compliance with applicable safety and environmental regulations. 6. Apparatus 6.1 Sample Container--Use metal sample containers of a type that ensures maximum safety and are resistant to corrosion by the product being sampled. A suitable material is stainless steel. The size of the container depends upon the amount of sample required for the laboratory tests to be made. The sample container should be fitted with an internal outage (ullage) tube to permit release of 20 % of the container capacity. The end of the container fitted with the outage (ullage) tube shall be clearly marked. Typical sample containers are shown in Figs. 1 and 2. If the container is to be transported, it must often conform to specifications published in Tariff No. 10, "I.C.C. Regulations for Transportation of Explosives and Other Dangerous Articles," its supplements, or reissues.

4. Significance and Use 4.1 Samples of liquefied petroleum gases are examined by various test methods to determine physical and chemical characteristics. The test results are often used for custody transfer and pricing determination. It is therefore essential that the samples be representative of the product to be tested. This practice is under the joint jurisdiction of ASTM Committee 13-2 on Petroleum and Petroleum Products and is the direct responsibility of Subcommittee D02.H on Liquefied Petroleum Gas. Current edition approved March 15, 1992. Published May 1992. Originally published as D 1265 - 53 T. Last previous edition D 1265 - 87. 2 Annual Book of ASTM Standards, Vois 05.01 and 05.05. s Annual Book of ASTM Standards, Vols 05.02 and 05.05. 4 Annual Book of ASTM Standards, Vol 05.03.

249

q~ D 1265 outlet Valve D

Outage (Ullage) Tube

Control valve A

To product source sampling valve

Inlet valve C

Vent valve B FiG. 1 TypicalSample Container and Sampling Connections

Valve

C

Outage (Ullage)

Valve

A

Valve D

~

Valve B Vent Pipe

FIG. 2 TypicalSample Container and Alternate Purging Connections

250

~

D 1265

6.2 Sample Transfer Line made of stainless steel tubing or other flexible metal hose, impervious to the product being sampled, is required. The most satisfactory line is one equipped with two valves on the sample-container end, Fig. 1, a control valve, A, and a vent valve, B.

D. Close outlet valve D and release the remainder of the sample in the liquid phase by opening vent valve B. Repeat the purging operation at least three times.

9. Transfer of Sample 9.1 Position the sample container securely in an upright position with outlet valve D at the top (Fig. 1) and both valves C and D closed. 9.1.1 Close vent valve B, open the control valve A, open inlet valve C, and fill container with the sample. Close inlet valve C and the valve at the product source. Open vent valve B. After the pressure is fully reduced, disconnect sample container from the transfer line. Discard the sample if a leak develops or if either valve is opened during subsequent handling of the sample container before performing the outage (ullage) operations outlined in section 10.

PROCEDURE

7. Purging Sample Transfer Line 7.1 Connect the ends of the transfer line securely to the product source and to the inlet valve C of the container. Close the control valve A, vent valve B, and inlet valve C, Fig. 1. Open the valve at the product source and purge the transfer line by opening the control valve A and the vent valve B. 8. Purging the Sample Container 8.1 If the history of the sample container contents is not known or if traces of the previous product could affect the analysis to be carded out, or both, use the following purge procedure: 8.l.i Connect valve D of the sample container to the sample transfer line with the container in an upright position ~nd valve C at the top (Fig. 2). 8.1.2 Close valves B, C, and D. Open valve A and then valves C and D. Fill sample container until liquid issues from valve C. Close valves C and D, then valve A on the sampling line. 8.1.3 Loosen the connection joining the sample container to the sample line and turn container through 180* such that valve D is at the top. Open valves C and D and drain out liquid.. 8.1.4 Return the sample container to position valve C at the top. Tighten connection to sample transfer line and repeat the purging operation at least three times. 8.2 If the history of the sample container contents is known, use the following purge procedure: 8.2.1 With the container in an upright position, Fig. l, and its outlet valve D at the top, close vent valve B and inlet valve C and open control valve A. Open inlet valve C and partly fill the container with sample by slowly opening the outlet valve D. Close the control valve A and allow part of the sample to escape in the vapor phase through outlet valve

10. Sample Outage (Ullage) 10.1 Immediately after obtaining the sample, place the container in an upright positioin with the outage (ullage) tube at the top. 10.1.1 Open outlet valve D slightly. Allow excess liquid to escape and close the valve at the first sign of vapor. If no liquid escapes, discard the sample and refill the container. 11 Checking for Leaks 11.1 After eliminating the excess liquid so that only 80 % of the sample remains, immerse in a water bath and check for leaks. If a leak is detected at any time during the sampling operation, discard the sample. Repair or replace the leaky container before obtaining another sample.

12. Care of Samples 12.1 Place samples in a cool location as soon as possible. Keep them there until all tests have been completed. Discard any samples in containers which develop leaks. Protect the valves on the sample container, either by packing the container in a crate in an approved manner or by using a protective cap, so that accidental unseating of the valve or tampering with it is avoided. 13 Keywords 13.1 liquified petroleum gases; LPG; sampling

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either respproved or withdrawn. Your comments are Invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend, ff you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103.

251

Designation: D 1298 - 85 (Reapproved 1990)el

An American National Standard British Standard 4714

Designation: API MPMS Chapter 9.1

®

Designation: 160/82

Standard Practice for Density, Relative Density (Specific Gravity), or API Gravity of Crude Petroleum and Liquid Petroleum Products by Hydrometer Method I This standard is issued under the fixed designation D 1298; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (e) indicates an editorial change since the last revision or reapproval.

This practice has been approvedfor use by agencies of tbe Department of Defense and for listing in the DoD Index of SpecOqcations and Standards. This practice has been approved by the sponsoring committees and accepted by the cooperating organizations in accordance with established procedures. e~ NOTE~Editorial changes were made throughout in May 1990.

1. Scope 1.1 This practice covers the laboratory determination, using a glass hydrometer, of the density, relative density (specific gravity), or API gravity of crude petroleum, petroleum products, or mixtures of petroleum and nonpetroleum products normally handled as liquids, and having a Reid vapor pressure (Test Method D 323, or IP 69) of (179 kPa) 26 lb or less. Values are measured on a hydrometer at convenient temperatures, readings of density being reduced to 15"C, and readings of relative density (specific gravity) and API gravity to 60"F, by means of international standard tables. By means of these same tables, values determined in any one of the three systems of measurement are convertible to equivalent values in either of the other two so that measurements may be made in the units of local convenience. 1.2 This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address all of the safety problems associated with its use. It is the responsibility of whoever uses this standard to consult and establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements, see 9.1. 2. Referenced Documents

2.1 ASTM Standards: D323 Test Method for Vapor Pressure of Petroleum Products (Reid Method)2 l This practice is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and API Committee on Petroleum Measurement and is the dit~t responsibility of Subcommittee 1302.02 on Joint ASTM.API Committee on Static Petroleum Measurement. Current edition approved Oct. 25, 1985. Published December 1985. Originally published as D 1298 - 53 T. Last previous edition D 1298 - 80. 2 Annual Book of ASTM Standards, Vo105.01.

D 1250 Guide for Petroleum Measurement Tables2 E 1 Specification for ASTM Thermometersa E 100 Specification for ASTM Hydrometers3 3. Terminology 3.1 Descriptions of Terms Specific to This Standard: 3.1.1 densityBfor the purpose of this practice, the mass (weight in vacuo) of liquid per unit volume at 15"C. When reporting results, explicitly state the density in units of mass (kilograms) and volume (litres), together with the standard reference temperature, for example, kilograms per litre at 15"C. 3.1.2 relative density (specific gravity)--for the purpose of this practice, the ratio of the mass of a given volume of liquid at 15"C (60"F) to mass of an equal volume of pure water at the same temperature. When reporting results, explicitly state the standard reference temperature, for example, relative density (specific gravity) 60/60"F. 3.1.3 API gravity,--a special function of relative density (specific gravity) 60/60"F, represented by: API gravity, deg - (141.5/sp gt 60/60"F) - 131.5 No statement of reference temperature is required, since 60"F is included in the definition. 3.1.4 observed values--values observed at temperatures other than the specified reference temperature. These values are only hydrometer readings and not density, relative density (specific gravity), or API gravity at that other temperature. 4. Field of Application 4.1 When used in connection with bulk oil measure3 Annual Book ofA S T M Standards,Vols 05.03 and 14.03.

252

~

D 1298 eter and the bottom of the cylinder. 7.3. I Hydrometer cylinders constructed of plastic materials shall be resistant to discoloration or attack by oil samples and must not become opaque under prolonged exposure to sunlight and oil samples. 7.4 Constant-TemperatureBath, for use when the nature of the sample requires a test temperature much above or below room temperature or the requirements of 9.8 cannot otherwise be met.

ments, volume correction errors are minimized by observing the hydrometer reading at a temperature close to that of the bulk oil temperature.

5. Summary of Practice 5.1 The sample is brought to the prescribed temperature and transferred to a cylinder at approximately the same temperature. The appropriate hydrometer is lowered into the sample and allowed to settle. After temperature equilibrium has been reached, the hydrometer scale is read, and the temperature of the sample is noted. If necessary the cylinder and its contents may be placed in a constant temperature bath to avoid excessive temperature variation during the test. 6. Significance and Use 6.1 Accurate determination of the density, relative density (specific gravity), or API gravity of petroleum and its products is necessary for the conversion of measured volumes to volumes at the standard temperatures of 15"C or 60*F. 6.2 Density, relative density (specific gravity), or API gravity is a factor governing the quality of crude petroleum; crude petroleum prices are frequently posted against values in degrees API. However, this property of petroleum is an uncertain indication of its quality unless correlated with other properties. 6.3 The hydrometer method is most suitable for determining the density, relative density (specific gravity), or API gravity of mobile transparent liquids. It can also be used for viscous oils by allowing sufficient time for the hydrometer to reach equilibrium, or for opaque oils by employing a suitable meniscus correction.

NOTE l - - T h e user should ascertain that the instruments used for this test conform to the requirements set out above with respect to materials,

dimensions, and scaleerrors. In caseswhere the instrumentis provided with a calibrationcertificateissuedby a recognizedstandardizingbody, the instrument is classed as certified and the appropriate corrections listed shall be applied to the observed readings. Instrumentswhich satisfy the requirementsof this test method, but are not provided with a recognizedcalibrationcertificate,are classedas uncertified.

8. Temperature of Test 8.1 The density, relative density (specific gravity), or API gravity by the hydrometer method is most accurate at or near the reference temperature of 15"C or 60*F. Use these or any other temperatures between -18 and +90"C (0 and 195"1=3, so far as it is consistent with the type of sample and necessary limiting conditions shown in Table 3. 8.2 When the hydrometer value is to be used to select multipliers for correcting volumes to standard temperatures, the hydrometer reading should be made preferably at a temperature within +3"C (+_5*F) of the temperature at which the bulk volume of the oil was measured (Note 2). However, in cases when appreciable amounts of light fractions may be lost during determination at the bulk oil temperature, the limits given in Table 3 should be applied.

7. Apparatus 7.1 Hydrometers, glass, graduated in units of density, relative density (specific gravity), or API gravity as required, conforming to ASTM specifications or specifications of the British Standards Institution as listed in Table 1. 7.2 Thermometers, having ranges shown in Table 2 and conforming to specifications of the American Society for Testing and Materials or the Institute of Petroleum. 7.3 HydrometerCylinder, clear glass, plastic (see 7.3.1), or metal. For convenience in pouring, the cylinder may have a lip on the rim. The inside diameter of the cylinder shall be at least 25 mm greater than the outside diameter of the hydrometer used in it. The height of the cylinder shall be such that the appropriate hydrometer floats in the sample with at least 25-mm clearance between the bottom of the hydromTABLE 1

NOTE 2--Volume and density (relative density (specific gravity), API gravity) correction tables are based on an average expansion for a number of typical materials. Since the same coefficients were used in computing both sets of tables, corrections made over the same temperature interval minimize errors arising from possible differences between the coefficients of the material under test and the standard coefficients. This effect becomes more important as temperatures diverge significantly from 15°C (60°F).

9. Procedure 9.1 Adjust the temperature of the sample (Warning-Flammable. Vapor harmful. See Annex A I.I). Values are measured in accordance with the information given in Section 8. Bring the hydrometer cylinder (Note 4) and thermometer to approximately the same temperature as the sample to be tested.

Recommended Hydrometers Range

Spec~catk~n

Type

BS 718:1960 L50 SP M50 SP BS 718:1960 L50 SP MS0 SP Specification E 100, Nos. 82H to 90H Specification E 100, Nos. 1H to 10H

special petroleum special petroleum long, plain long, plain

Units density, kg/litre at 150C relative density (specific gravity) 60/60°F relative density (specific gravity), 60/60*F API

Total

Interval

Error

Meniscus Correct~n

0.600 to 1.100 0.600 to 1.100

0.050 0.050

0.0005 0.001

+ 0.0003 ± 0.0006

+ 0.0007 + 0.0014

0.600 to 1.100 0.600 to 1.100

0.050 0.050

0.0005 0.001

± 0.0003 ± 0.0006

+ 0.0007 + 0.0014

0.650 to 1.100

0°050

0.0005

± 0.0005

0.1

± 0.1

-1 to + 101

253

Scale Each Unit

12

(~) D 1298 TABLE 2 Specification IP 64 C Specification E 1 No. 12 C IP 64 F Specification E 1 No. 12 F

Recommended Thermometers

Type density, wide range gravity relative density (specific gravity), wide range gravity

9.2 Transfer the sample to a clean hydrometer cylinder without splashing, to avoid the formation of air bubbles, and to reduce to a minimum evaporation of the lower boiling constituents of more volatile samples. Transfer highly volatile samples to the cylinder by water displacement or by siphoning (Note 3). Remove any air bubbles formed, after they have collected on the surface of the sample, by touching them with a piece of clean filter paper before inserting the hydrometer.

TABLE 3 Highly volatile Moderately volatile

120°C (250=F) and below

Moderately volatile and visoous Nonvolatile

120°C (250°F) and below

Graduation Interval

C C F F

-20 to + 102 -20 to + 102 - 5 to + 215 - 5 to + 215

0.2 0.2 0.5 0.5

Scale Error ± ± ± ±

0.1 0.1 0.25 0.25

NOTE 4--When using a plastic cylinder, dissipate any static charge. Static chargesoften build up when using such cylindersand may prevent the hydrometer from floating freely. 9.7 With an opaque liquid take a reading by observing, with the eye slightly above the plane of the surface of the liquid, the point on the hydrometer scale to which the sample rises. This reading, at the top of the meniscus, requires correction since hydrometers arc calibrated to be read at the principal surface of the liquid. The correction for the particular hydrometer in use may b¢ determined by observing the maximum height above the principal surface of the liquid to which oil rises on the hydrometer scale when the hydrometer in question is immersed in a transparent oil having a surface tension similar to that of the sample under test (see Fig. 2).

9.3 Place the cylinder containing the sample in a vertical position in a location free from air currents. Ensure that the temperature of the sample does not change apprcciably during the time necessary to complete the test; during this period, the tempcraturc of the surrounding medium should not change more than 2°C (5"F). When testing at temperatures much above or below room temperature, a constanttemperature bath may be necessary to avoid excessive temperature changes. 9.4 Lower the hydrometer gently into the sample. Take care to avoid wetting the stem above the level to which it will be immersed in the liquid. Continuously stir the sample with the thermometer, taking care that the mercury thread is kept fully immersed and that the stem of the hydrometer is not wetted above the immersion level. As soon as a steady reading is obtained, record the temperature of the sample to the nearest 0.25"C (0.5°F) and then remove the thermometer. 9.5 Depress the hydrometer about two scale divisions into the liquid, and then release it. The remainder of the stem of the hydrometer, which is above the level of the liquid, must be kept dry since unnecessary liquid on the stem affects the reading obtained. With samples of low viscosity, impart a slight spin to the hydrometer on releasing to assist in bringing it to rest, floating freely away from the walls of the cylinder. Allow sufficient time for the hydrometer to come to rest, and for all air bubbles to come to the surface. This is particularly necessary in the case of more viscous samples. 9.6 When the hydrometer has come to rest, floating freely away from the walls of the cylinder (Note 4), estimate the hydrometer scale reading to the nearest 0.0001 relative

Initial Boiling Point

Range

density (specific gravity) or density or 0.05" API. The correct hydrometer reading is that point on the hydrometer scale at which the principal surface of the liquid cuts the scale. Determine this point by placing the eye slightly below the level of the liquid and slowly raising it until the surface, first seen as a distorted ellipse, appears to become a straight line cutting the hydrometer scale. (See Fig. 1.)

NOTE 3--Highly volatilesamplescontaining alcoholsor other watersoluble material should alwaysb¢ transferred by siphoning.

Sample Type

Scale

NOTE 5--Alternatively, corrections as given in Table I may be applied. 9.8 Immediately after observing the hydrometer scale value, again cautiously stir the sample with the thermometer keeping the mercury thread fully immersed. Record the temperature of the sample to the nearest 0.2"C (0.5"F) (Note 6). Should this temperature differ from the previous reading by more than 0.5"C (I'F), repeat the hydrometer test and then thermometer observations until the temperature becomes stable within 0.5"C (l'F). NOTE 6mAfter use at a temperature higher than 38"C (IO0"F), allow

all hydrometers of the lead shot in wax type to drain and cool in a vertical position.

I0. Calculations and Report 10.1 Apply any relevant corrections to the observed thermometer reading (for scale or bulb) and to the hydrometer reading (scale). For opaque samples, make the appro-

Umiting Conditions end Test Temperatures Other Limits

Test Temperature

Reid vapor pressure below 26 Ib

Cool in original cloud container to 2°C (35°F) or lower Cool in original closed container to 180C (65°F) or lower

viscosity too high at 18°C (65°F)

Above 120°C (250°F)

Heat to minimum temperature to ot)tain sufficient

fUdny

Use any temperature between -18 and 90°C (0 and 195°F) as convenient Test at 15 + 0.2=C (60 + 0.5°F)

Mixtures with nonpetroleum products

254

q~) D 1298

--HORIZONTALPLANE SURFACEOFLIQUID

SEEDETAIL

"BOTTOMOFMENISCUS

LIQUID

READSCALE AT THISPOtNT

•

-

[

/

LIQUID

HORIZONTAL PLANE ~ SURFACE OFLIQUID

~

~

SEEDETAIL,

~

.~~_~

[ f-'[

HORIZONTAL PLANE SURFAC[OFUOUaD

__. ]-BOTTOMOFMENISCUS

~ R O R , Z O N ~ A . PLA.E READS C A L E ~ l- I / \ SURFACEOr L,QUID

MENISCUS

DETAIL

DETAIL FIG. 2 Hydrometer Scale Rending for Opaque Fluids4

FIG. 1 Hydrometer Scale Reading for Tmnnpnmnt Uquid$ ~ priate correction to the observed hydrometer reading as given in 9.7. Record to the nearest 0.0001 density or relative density (specific gravity) or 0.1" API the final corrected hydrometer scale reading (Note 7). After application of any relevant corrections record to the nearest 0.5"C or I'F, the mean of the temperature values observed immediately before and after the final hydrometer reading. NOTE 7DHydrometer scale readings at temperatures other than calibration temperatures (15"C or 60"F) should not be considered as more than scale readings since the hydrometer bulb changes with temperature. 10.2 To convert corrected values from 10.1 to standard temperature, use the following from the Petroleum Measurement Tables (Guide D 1250): 10.2.1 When a density scaled hydrometer has been employed, use Tables 53 A or 53 B to obtain density at 150C. 10.2.2 When a relative density (specific gravity) hydrometer has been employed, use Tables 23 A or 23 B to obtain Relative Density (Specific Gravity) 60/60"F, and 10.2.3 When an API gravity scaled hydrometer has been employed, use Tables 5 A or 5 B to obtain the gravity in API degrees. 10.3 When a value is obtained with a hydrometer scaled in one of the units described herein and a result is required in

one of the other units, make the conversion by one of the appropriate tables given in Standard D 1250, Petroleum Measurement Tables, Volume XI/XII. For conversion from density at 150C, use Table 51; from relative density (specific gravity) 60/60"1:, use Table 21; from API gravity, use Table 3. 10.4 Report the final value as density in kilograms per litre at 150C, or as relative density (specific gravity) at 60/60"F, or as gravity in degrees API, as applicable. 11. Precision and Bias 11.1 Precision--The precision of the method as determined by statistical examination of interlaboratory results is as follows: 11.1.1 Repeatability--The difference between two test results, obtained by the same operator with the same apparatus under constant operating conditions on identical test material, would in the long run, in the normal and correct operation of the test method, exceed the following values only in one case in twenty:

Product Transparent Nonviscous Opaque

'*Editorialchangesto Figs. 1 and 2 ate presentlyunderway.

Temperature Range - 2 to 24.5"C 29 to 76"F 42 to 78"F - 2 to 24.5"C 29 to 76"F 42 to 78"F

255

Units density relative density (specific gravity) APl gravity density relative density (specific gravity) API gravity

Repeatability 0.0005 0.0005 0. I 0.0006 0.0006 0.2

q~ D 1298 11.1.2 Reproducibility--The difference between two single and independent results obtained by different operators working in different laboratories on identical test material would, in the long run, in the normal and correct operation of the test method, exceed the following values only in one case in twenty: Product Transparent Nonviscous

Temperature Range - 2 to 24.5"C 29 to 76"F

Units density relative density (six'cific gravity)

Reproducibility 0.0012 0.0012

Product Opaque

Temperature Range 42 to 78"F - 2 to 24.5"C 29 to 76"F 42 to 78"F

Units AP! gravity density relative density (spccific gravity) APl gravity

(Mandatory Information) AI. PRECAUTIONARY STATEMENTS Keep container closed. Use with adequate ventilation. Avoid prolonged breathing of vapor. Avoid prolonged or repeated skin contact.

Warning--Flammable. Vapors harmful. Keep away from heat, sparks, and open flame.

The American Society for Testing and Materials takes no position respecting the vahdtty o1 any patent rights asserted m connection with any item menOoned in th/s standard Users of this standard are expressly advised that determination of the vahdtty of any such patent rights, and the risk of infnngement of such rights, are entirely their own responsibility. This standard is sublect to rewsion at any time by the responsible techmcal committee and must be reviewed every hve years and tf not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 100 Barr Harbor Drwe, West Conshohocken, PA 19428

256

0.3 0.0015 0.0015 0.5

11.1.3 For very viscous products, or when the conditions given in 11.1.1 and 11.1.2 are not compiled with, no specific variations can be given. 11.2 Bias--A statement of bias is being developed for this test method.

ANNEX

AI.1 Petroleum Liquids

Reproducibility

Designation: D 1319

IP@ IJll IN~HIIIH I t l Iq I K ( ) l I I I M

-

95a

An American National Standard

Designation: 156/95

Standard Test Method for Hydrocarbon Types in Liquid Petroleum Products by Fluorescent Indicator Adsorption 1 This standard is issued under the fixed designation D 1319; the number immediately following the d 'emgnetion indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year oflaet reapproval. A superscript epsilon (0 indicates an editorial change since the last revision or reapproval.

This test method has been approved by the sponsoring committees and accepted by the cooperating societies in accordance with established procedures. This standard has been approvedfor use by agencies of the Department of Defense to replace Method 3703 of Federal Test Method Standard No. 791b. Consult the DoD Index of SpecO~¢ationsand Standards for the spec(ficyear of issue which has been adopted by the Department of Defense.

components are analyzed, the results must be corrected to a total-sample basis. 1.6 The values stated in SI units are to be regarded as standard.

1. S c o p e 1.1 This test method is for determining hydrocarbon types over the concentration ranges from 5 to 99 volume % aromatics, 0.3 to 55 volume % olefins, and 1 to 95 volume % saturates in petroleum fractions that distill below 315"C. This test method may apply to concentrations outside these ranges, but the precision has not been determined. Samples containing dark-colored components that interfere in reading the chromatographic bands cannot be analyzed. 1.2 This test method is intended for use with full boiling range products. Cooperative data have established that the precision statement does not apply to narrow boiling petroleum fractions near the 315"C limit. Such samples are not eluted properly, and results are erratic. 1.3 The applicability of this test method to products derived from fossil fuels other than petroleum, such as coal, shale, or tar sands, has not been determined, and the precision statement may or may not apply to such products. 1.4 The precision statement for this test method has been determined with unleaded fuels that do not contain oxygenated blending components. It may or may not apply to automotive gasolines containing lead antiknock mixtures or oxygenated gasoline blending components, or both. 1.5 The following oxygenated blending components: methanol, ethanol, methyl-tert-butylether, tert-amylmethylether and ethyl-tert-butylether do not interfere with the determination of hydrocarbon types at concentrations normally found in commercial blends. These oxygenated components are not detected since they elute with the alcohol desorbent. Other oxygenated compounds must be individually verified. When samples containing oxygenated blending

Note l--For the determination of olefins below 0.3 volume %, other methods are available, such as Test Method D 2710.

1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements, see Notes 3, 4, 5, 6, 7, and 10. 2. Referenced D o c u m e n t s

2.1 ASTM Standards: D 770 Specification for Isopropyl Alcohol 2 D 1655 Specification for Aviation Turbine Fuels 3 D 2001 Test Method for Depentanization of Gasoline and Naphthas 3 D 2427 Test Method for Determination of C2 through C5 Hydrocarbons in Gasolines by Gas Chromatography ~ D2710 Test Method for Bromine Index of Petroleum Hydrocarbons by Electrometrie Titration 4 D 3663 Test Method for Surface Area of Catalysts5 D4057 Practice for Manual Sampling of Petroleum and Petroleum Products4 D 4815 Test Method for Determination of MTBE, ETBE, TAME, DIPE, tertiary.Amyl Alcohol and Ct to C4 Alcohols in Gasoline by Gas Chromatography 5 E 11 Specification for Wire-Cloth Sieves for Testing Purposes6 2.2 Other Standards:

i This test method is under the jurisdiction of ASTM Committee D.2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee 1302.04 on Hydrocarbon Analyses. In the IP, this test method is under the jurisdiction of the Standardization Committee. Current edition approved Oct. 10, 1995. Published December 1995. Originally published as D 1319 - 54 T. last previous edition D 1319 - 95.

2 Annual Book of ASTM Standards, Vol 06.04. 3 Annual Book of ASTM Standards, Voi 05.0 I. 4 Annual Book ofASTM StandardJ,Vol 05.02. 5 Annual Book ofASTM Standard~, Vol 05.03. 6 Annual Book of ASTM Standards, Vol 14.02.

257

~

D 1319 TABLE 1

GC/OFID EPA Test Method-Oxygen and Oxygenate Content Analysis7 BS 4108 3. Terminology

3.1 Descriptions of Terms Specific to This Standard: 3.1.1 saturates--the volume percent of alkanes plus cy-

on 60 on 80 on 100 through 200

cloalkanes. 3.1.2 olefins--the volume percent of alkenes, plus cycloalkenes, plus some dienes. 3.1.3 aromatics--the volume percent of monocyclic and polycyclic aromatics, plus aromatic olefins, some dienes, compounds containing sulfur and nitrogen, or higher boiling oxygenated compounds (excluding those listed in 1.5).

430 to 530 5.5 to 7.0 4,5 to 10.0 50 max p.m 250 180 150 75

Mass-~= 0.0 1.2 5.0 15.0

max max max max

A Detailed requirements for these sieves are given In Specification E 11, and BS410: 1943.

shall not vary by more than 0.3 mm in any part of the analyzer section. In glass-sealing the various sections to each other, long-taper connections shall be made instead of shouldered connections. Support the silica gel with a small piece of glass wool located between the ball and socket of the 12/2 spherical joint and covering the analyzer outlet. The column tip attached to the 12/2 socket shall have a 2-ram internal diameter. Clamp the ball and socket together and ensure that the tip does not tend to slide from a position in a direct line with the analyzer section during the packing and subsequent use of the column. 7.1.2 For convenience, adsorption columns with standard wall tubing, as shown on the left in Fig. l, can be used. When using standard wall tubing for the analyzer section, it is necessary to select tubing of uniform bore and to provide a leakproof connection between the separator and the analyzer sections. Calibrations of standard wall tubing would be impractical; however, any variations of 0.5 mm or greater, as measured by ordinary calipers, in the outside diameter along the tube can be taken as an indication of irregularities in the inner diameter and such tubing should not be used. Draw out one end of the tubing selected for the analyzer section to a fine capillary to retain the gel. Connect the other end of the analyzer section to the separator section with a 30-mm length of vinyl tubing, making certain that the two glass sections touch. To ensure a leakproof glass-to-vinyl seal with the analyzer section, it is necessary to heat the upper end of the analyzer section until it is just hot enough to melt the vinyl, then insert the upper end of the analyzer section into the vinyl sleeve. Alternatively, this seal can be made by securing the vinyl sleeve to the analyzer section by wrapping it tightly with soft wire. 7.2 Zone-Measuring Device--The zones may be marked with a glass-writing pencil and the distances measured with a meter rule, with the analyzer section lying horizontally. Alternatively, the meter rule may be fastened adjacent to the column. In this case, it is convenient to have each rule ftted with four movable metal index clips (Fig. 1) for marking zone boundaries and measuring the length of each zone. 7.3 Ultraviolet Light Source, with radiation predominantly at 365 nm is required. A convenient arrangement consists of one or two 915-ram or 1220-ram units mounted vertically along the apparatus. Adjust to give the best fluorescence. 7.4 Electric Vibrator, for vibrating individual columns or the frame supporting multiple columns. 7.5 Hypodermic Syringe, l-mL, graduated to 0.01 or 0.02 mL, with needle 102 mm in length. Needles of No. 18, 20, or 22-gage are satisfactory.

4. Summary of Test Method 4.1 Approximately 0.75 mL of sample is introduced into a special glass adsorption column packed with activated silica gel. A small layer of the silica gel contains a mixture of fluorescent dyes. When all the sample has been adsorbed on the gel, alcohol is added to desorb the sample down the column. The hydrocarbons are separated according to their adsorption affinities into aromatics, olefins, and saturates. The fluorescent dyes are also separated selectively, with the hydrocarbon types, and make the boundaries of the aromatic, olefin, and saturate zones visible under ultraviolet light. The volume percentage of each hydrocarbon type is calculated from the length of each zone in the column. 5. Significance and Use 5.1 The determination of the total volume percent of saturates, olefins, and aromatics in petroleum fractions is important in characterizing the quality of petroleum fractions as gasoline blending components and as feeds to catalytic reforming processes. This information is also important in characterizing petroleum fractions and products from catalytic reforming and from thermal and catalytic cracking as blending components for motor and aviation fuels. This information is also important as a measure of the quality of fuels, such as specified in Specification D 1655. 6. Interferences 6.1 Errors in the aromatic and low contains significant Such samples are D 2001.

Silica Gel Specifications

Surface area, m=/g pH of 5 ~ water slurry Loss on ignition at 9550C, mass-~ Iron as Fe=Oa, dry basis, mass-ppm Particle Size Sieve Number A

direction of high saturate values and low olefin values can result if the sample amounts of C5 and lighter hydrocarbons. to be depentanized by Test Method

7. Apparatus

7.1 Adsorption Columns, with precision bore ("true bore" IP designation) tubing as shown on the right in Fig. 1, made of glass and consisting of a charger section with a capillary neck, a separator section, and an analyzer section; or with standard wall tubing, as shown on the left in Fig. 1. 7.1.1 The inner diameter of the analyzer section for the precision bore tubing shall be 1.60 to 1.65 mm. In addition the length of an approximately 100-mm thread of mercury Code of Federal Regulations, Part 80 of Title 40, 80.46(g); also published in the Federal Register, Vol 59, No. 32, Feb. 16, 1994, p 7828. Available from Library of Congress. ' Available from British Standards Institute, 2 Park St., London, England WIA2B5.

258

F

P*etSU~lhg

..........

Got

$ghet i¢¢~1Joint 2O/IZ

! STANDARD COLUMN

12 t 0

i

t

i

PRECISION

BORE COLUMN I

150 ChOrqer -PlCk Gel to this Level-

i

2 I O - - -"

150 Charger

L

Necu •' °

'

2 I D-

,

SO

Neck

~ , [,~.

I

J

t

~SIO

~

StD

t90 Sipo¢olor

I

Tip 3S 0 D, 12 t 0"~

f/J=~

Vinyl T.b,.~ lib" SJz~

~O00,~tSt 0 Standard Wall Tub=ag -_ _ ~

" •f

1.60 - 1.65 Precision B o r e ~ Capillary Tubing

t t2~.O Anolyller

~.

All Dimensions in Mtllimttets

FIG. 1 Adsorption Columns with Standard Wall (left) and Precision Bore (right) Tubing in Analyzer Section

shallow vessel at 175°C for 3 h. Transfer the dried gel to an air tight container while still hot, and protect it thereafter from atmospheric moisture.

7.6 Regulator, 2-stage, 0 to 103 kPa gage delivery range. 8. Reagents and Materials 8.1 Silica Gel, 9 manufactured to conform to the specifications shown in Table 1. Determine the surface area of the gel by Test Method D 3663. Determine the pH of the silica gel as follows: Calibrate a pH meter with standard pH 4 and pH 7 buffer solutions. Place 5 g of the gel sample in a 250-mL beaker. Add 100 mL of water and a stirring bar. Stir the slurry on a magnetic stirrer for 20 rain and then determine the pH with the calibrated meter. Before use, dry the gel in a

NoTE 2--Some batches of silica gel that otherwise meet specifications have been found to produce olefin boundary fading. The exact reason for this phenomenon is unknown but will affect accuracy and precision.

8.2 Fluorescent Indicator Dyed C e l i a standard dyed gel, i° consisting of a mixture of recrystallized Petrol Red AB4 and purified portions of the olefin and aromatic dyes ,o Available from UOP, Refining Chemicals Dept., 25 E. Algonquin Rd., Des Plaines, IL 60017-5017, by requesting "F1A Standard Dyed Gel," UOP Product

Available from W. R. Grace and Co., Davison Chemical Div., Baltimore, MD 21203 by specifying Code 923.

No. 675.

259

~

D 1319 12.2 Attach the filled column to the apparatus assembly in the darkened room or area, and when a permanently mounted meter rule is used, fasten the lower end of the column to the fixed rule with a rubber band. 12.3 Chill the sample and a hypodermic syringe to 2 to 4°C. Draw 0.75 + 0.03-mL of sample into the syringe and inject the sample 30 mm below the surface of the gel in the charger section. 12.4 Fill the charger section to the spherical joint with isopropyl alcohol. Connect the column to the gas manifold and apply 14 kPa gas pressure for 2.5 min to move the liquid front down the column. Increase the pressure to 34 kPa gage for another 2.5 min and then adjust the pressure required to give a transit time of about l h. Usually a gas pressure of 28 to 69 kPa gage is needed for gasoline-type samples and 69 to 103 kPa gage for jet fuels. The pressure required will depend on the tightness of packing of the gel and the molecular weight of the sample. A transit time of l h is optimum; however, high-molecular weight samples may require longer transit times. 12.5 After the red, alcohol-aromatic boundary has advanced 350 mm into the analyzer section, make a set of readings by quickly marking the boundary of each hydrocarbon-type zone (see Note 9) observed in ultraviolet light (Note 10) in the following sequence. For the nonfluorescent saturate zone, mark the front of the charge and the point where the yellow fluorescence first reaches its maximum intensity; for the upper end of the second, or olefin zone, mark the point where the first intense blue fluorescence occurs; finally, for the upper end of the third, or aromatic zone, mark the upper end of a reddish or brown zone. With colorless distillates, the alcohol-aromatic boundary is clearly defined by a red ring of dye. However, impurities in cracked fuels often obscure this red ring and give a brown coloration, which varies in length, but which shall be counted as a part of the aromatic zone, except that when no blue fluorescence is present, the brown or reddish ring shall be considered as part of the next distinguishable zone below it in the column. If the boundaries have been marked off with index clips, record the measurements.

obtained by chromatographic adsorption following a definite, uniform procedure, and deposited on silica gel. The dyed gel shall be stored in a dark place under an atmosphere of nitrogen. When stored under these conditions the dyed gel can have a shelf life of at least five years. It is recommended that portions of the dyed gel be transferred as required to a smaller working vial from which the dyed gel is routinely taken for analyses. 8.3 Isoamyl Alcohol, (3-methyl-l-butanol) 99 %. NOTE 3: Warning--Flammable.Health hazard. 8.4 Isopropyl Alcohol, (2-propanol) 99 %, conforming to Specification D 770. NoTE 4: Warning--Flammable.Health hazard. 8.5 Pressuring Gas--Air (or nitrogen) delivered to the top of the column at pressures controllable over the range from 0 to 103 kPa gage. NOTE 5: Warning--Compressedgas under high pressure. 8.6 Acetone, reagent grade, residue free. NOTE 6: Warning--Flammable.Health hazard. 8.7 Buffer Solutions, pH 4 and 7.

9. Sampling 9.1 Obtain a representative sample according to sampling procedures in Practice D 4057. Store the sample until ready for analysis at 2 to 4"C. NOTE 7: Warning--Flammable.Health hazard. 10. Preparation of Sample 10.1 Samples containing any of the following: C3 or lighter hydrocarbons, more than 5 % (24 hydrocarbons, or more than I0 % (24 and C5 hydrocarbons can be depentanized in accordance with Test Method D 2001. 11. Preparation of Apparatus 11.1 Mount the apparatus assembly in a darkened room or area to facilitate observation of zone boundaries. For multiple determinations, assemble an apparatus that includes the ultraviolet light source, a rack to hold the columns, and a gas manifold system with spherical joints to connect to the desired number of columns.

NOTE 9: Precaution--Avoid touching the column with the hands during this operation. NOTE 10: Precaution--Direct exposure to ultraviolet light can be harmful, and operatorsshouldavoid this as far as possible,particularly with regardto their eyes.

12. Procedure 12.1 Freely suspend the column from a loose-fitting clamp placed immediately below the spherical joint of the charger section. While vibrating the column along its entire length, add small increments of silica gel through a glass funnel into the charger section until the separator section is half full. Stop the vibrator and add a 3 to 5-mm layer ofdyed gel. Start the vibrator and vibrate the column while adding additional silica gel. Continue to add silica gel until the tightly packed gel extends 75 mm into the charger section. Wipe the length of the column with a damp cloth while vibrating the column. This aids in packing the column by removing static electricity. Vibrate the column after filling is completed for about 4 min. NOTE 8--More than one column can be prepared simultaneouslyby mounting several on a frame or rack to which an electric vibrator is attached.

12.6 When the sample has advanced another 50 mm down the column, make a second set of readings by marking the zones in the reverse order as described in 12.5 so as to minimize errors due to the advancement of boundary positions during readings. If the marking has been made with a glass-writing pencil, two colors can be used to mark off each set of measurements and the distances measured at the end of the test with the analyzer section lying horizontally on the bench top. If the boundaries have been marked off with index clips, record the measurements. 12.7 Erroneous results can be caused by improper packing of the gel or incomplete elution of hydrocarbons by the alcohol. With precision bore columns, incomplete elution can be detected from the total length of the several zones, which must be at least 500 mm for a satisfactory analysis. With standard wall tubing, this criterion of total sample

260

~

D 1319

length is not strictly applicable because the inside diameter of the analyzer section is not the same in all columns. NOTE 1i--For samples containing substantial amounts of material boiling above 204"C, the use of isoamyl alcohol instead of isopropyl alcohol may improve elution.

TABLE 2

Volume % Level

Rep~t~llty

5

0.7

1.5

15 25 35 45 50 55 65 75 65 95 99

1.2 1.4 1.5 1.6 1.6 1.6 1.5 1.4 1.2 0,7 0.3

2.5 3.0 3.3 3.5 3.5 3.5 3.3 3.0 2.5 1.5 0.7

Ola~l$

1 3 5 10 15 20 25 30 35 40 45 50 55

0.4 0.7 0.9 1.2 1.5 1.6 1.8 1.9 2.0 2.0 2.0 2.1 2.0

1.7 2.9 3.7 5.1 6.1 6.8 7.4 7.8 8.2 8.4 8.5 8.6 8.5

Saturates

1 5 15 25 35 45 50 55 65 75 85 95

0.3 0.8 1.2 1.5 1.7 1.7 1.7 1.7 1.7 1.5 1.2 0.3

1.1 2.4 4.0 4.8 5.3 5.6 5.6 5.6 5.3 4.8 4.0 2.4

Aromatics

12.8 Release the gas pressure and disconnect the column. To remove used gel from the precision bore column, invert it above a sink and insert through the wide end a long piece of No. 19-gage hypodermic tubing with a 45* angle tip. By means of 6-mm outside diameter copper tubing at the opposite end for attaching a rubber tube, connect to a water tap and flush with a rapid stream of water. Rinse with residue-free acetone and dry by evacuation. 13. Calculation 13.1 For each set of observations calculate the hydrocarbon types to the nearest 0.1 volume percent as follows: Aromatics, % volume : (L,)/L) x 1O0 (1) Olefins, % volume = ( L o l l ) x 100 (2) Saturates, % volume = ( L J L ) x 100 (3) where: Z a = length of the aromatic zone, ram, Lo -- length of the olefin zone, ram, L~ = length of the saturate zone, mm, and L = sum o f L a + L o + L s. Average the respective calculated values for each type and report as directed in 14.1. If necessary, adjust the result for the largest component so that the sum of the components is 100 %. 13.2 Equations 1, 2, and 3 calculate concentrations on an oxygenate-free basis and are correct only for samples that are composed exclusively of hydrocarbons. For samples that contain oxygenated blending components (see 1.5), the above results can be corrected to a total sample basis as follows: c'

:

c x

100 - B l-----~-

Reproducibility and Repeatability-Oxygenate Free Samples

TABLE 3

(4)

Reproducibility and Repeatability for Oxygenate Containing Samples Range

where: C ' = concentration of hydrocarbon type (% volume) on a total sample basis, C = concentration of hydrocarbon type (% volume) on an oxygenate-free basis, and B = concentration of total oxygenate blending components (% volume) in sample as determined by Test Method D 4815, or GC/OFID or equivalent.

Aromatics

Oleflns Saturates

Reproducibility

18 - 40

4 - 33 45 - 68

RepeetabUity, Volume %

Reproducibility

1.3

3.7

0.2578Xo.s

0.8185X o.eA 4.2

1.5

'~ X - the volume Y, of oleflrm.

15. Precision and Bias n 15.1 The following criteria are to be used for judging the acceptability of results (95 % probability): 15.1.1 R e p e a t a b i l i t y - - T h e difference between successive test results, obtained by the same operator with the same apparatus under constant operating conditions on identical test material would, in the long run, in the normal and correct operation of the test method, exceed the values in Tables 2 or 3 only in one case in twenty. 15.1.2 R e p r o d u c i b i l i t y - - T h e difference between two single and independent results, obtained by different opera-

14. Report

14.1 Report the averaged value for each hydrocarbon type (corrected to a total sample basis, if oxygenates are present) to the nearest 0.1 volume % and the total volume % oxygenates in the sample as calculated. 14.1.1 Results for samples that have been depentanized must be identified as being for the C 6 and heavier portion of the sample. Alternatively, the C5 and lighter portion of the sample can be analyzed for olefins and saturates in accordance with Test Method D 2427. Using these values and the percentage of overhead and bottoms, the hydrocarbon type distribution in the total sample can be calculated.

it Datasupportingthe precisionobtainedfroma roundrobintestforoxygenate containing samples in Table 3 has been filed in a research report at ASTM headquarters.RequestRR:D02-1361. 261

~

D 1319

tors working in different laboratories on identical test materiai would, in the long run, in the normal and correct operation of the test method, exceed the values in Tables 2 or 3 only in one case in twenty. 15.1.3 Table 2 shall be used for judging repeatability and reproducibility of non-oxygenate containing samples. Table 3 shall be used for judging the repeatability and reproducibility of oxygenate-containing samples.

15.2 BiasmBias cannot be determined because there are no acceptable reference materials suitable for determining the bias for the procedure in this test method. NOTE 12--The precision specified in Table 3 was determined for samples which were not depentanized. 16. Keywords 16.1 aromatics; fluorescent indicator absorption (FIA); hydrocarbon types; olefins; saturates

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and ff not revised, either reepproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend, ff you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 100 Barr Harbor Drive, West Conshoheckec, PA 19428.

262

Designation: D 1322

T H E IN~TITUTF o t pFTROLFUM

-

97

An American National Standard

Designation: 57/95

Standard Test Method for Smoke Point of Kerosine and Aviation Turbine Fuel I This standard is issued under the fixed designation D 1322; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (0 indicates an editorial change since the last revision or reapproval.

This standard has been approved for use by agencies of the Department of Defense. Consult the DoD Index of Specifications and Standards for the specific year of issue which has been adopted by the Department of Defense.

1. Scope 1. l This test method covers a procedure for determination of the smoke point of kerosine and aviation turbine fuel.

tween 140 and 300"C, generally used in lighting and heating applications. 3.1.3 smoke pointnthe maximum height, in millimetres, of a smokeless flame of fuel burned in a wick-fed lamp of specified design.

NOTE l - - T h e r e is good correlation between L u m i n o m e t e r n u m b e r

(Test Method D 1740) and smoke point which is represented in Appendix Xl.

4. Summary of Test Method 4.1 The sample is burned in an enclosed wick-fed lamp that is calibrated daily against pure hydrocarbon blends of known smoke point. The maximum height of flame that can be achieved with the test fuel without smoking is determined to the nearest 0.5 ram.

1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 2. Referenced Documents

2.1 A S T M Standards: D 1740 Test Method for Luminometer Number of Avi,-.tion Turbine Fuels2 D4057 Practice for Manual Sampling of Petroleum and Petroleum Products3 2.1 IP Standard: IP 57/95 Smoke Point4 NOTE 2 - - O n l y IP 57/95 published in 19954 is equivalent to D 1322;

earlier versions of IP 57 were not equivalent.

2.3 ISO Standard? ISO 3014:1993(E) Petroleum Products--Determination of the Smoke Point of Kerosine 3. Terminology

3.1 Definitions of Terms Specific to This Standard: 3.1.1 aviation turbine fuel--refined petroleum distillate, generally used as a fuel for aviation gas turbines. 3.1.1.1 Discussion~Different grades are characterized by volatility ranges, freeze point, and by flash point. 3.1.2 kerosine--refined petroleum distillate, boiling be-

5. Significance and Use 5.1 This test method provides an indication of the relative smoke producing properties of kerosines and aviation turbine fuels in a diffusion flame. The smoke point is related to the hydrocarbon type composition of such fuels. Generally the more aromatic the fuel the smokier the flame. A high smoke point indicates a fuel of low smoke producing tendency. 5.2 The smoke point (and Luminometer number with which it can be correlated) is quantitatively related to the potential radiant heat transfer from the combustion products of the fuel. Because radiant heat transfer exerts a strong influence on the metal temperature of combustor liners and other hot section parts of gas turbines, the smoke point provides a basis for correlation of fuel characteristics with the life of these components. 6. Apparatus

6.1 Smoke Point Lamp, as shown in Fig. 1 and described in detail in Annex A 1. 6.2 Wick, of woven solid circular cotton of ordinary quality, having the following characteristics:

This test method is under the jurisdiction of ASTM Committee 1)-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.J0.07 on Combustion C'haractedsties. Current edition approved June 10, 1997. Published October 1997. Originally published as D 1322 - 54T. Last previous edition D 1322 -96. 2 Annual Book of ASTM Standards, Vo105.01. 3 Annual Book of ASTM Standards, Vo105.02. 4 Standard Methods for Analysis and Testing of Petroleum and Related Products, 1995, Institute of Petroleum, 61 New Cavendish St., London WIM 8AR, England. s Available from American National Standards Institute, 11 W. 42nd St., 13th Floor, New York, NY 10036.

Casing Filling Weft Picks

17 ends, 66 tex by 3 9 ends, 100 tex by 4 40 tex by 2 6 per centimetre

6.3 Pipettes or Burettes, Class A. 7. Reagents and Materials 7.1 Toluene, ASTM Reference Fuel grade.

NOTE 3: Warning--Flammable,vapor harmful.(See Annex A2.1.) 263

q~ D 1322 NOTE 6: Warning--Extremely flammable, vapor harmful if inhaled. (See Annex A2.4.)

8. Sampling and Preparation of Samples 8.1 It is recommended samples shall be taken by the procedures described in Practice D 4057. Use the sample as received. Allow all samples to come to ambient temperature (20 _+ 5"C), without artificial heating. If the sample is hazy or appears to contain foreign material, filter through qualitative filter paper.

GHIMNIy

SGAL~... WIGK (|UIDE~

9. Preparation of Apparatus

GALLERY,

\~

/

9.1 Place the lamp in a vertical position in a room where it can be completely protected from drafts. Carefully inspect each new lamp to ensure that the air holes in the gallery and the air inlets to the candle holder are all clean, unrestricted and of proper size. The gallery shall be so located that the air holes are completely unobstructed. NOTE 7--Slight variations in these items all have a marked effect on the precision of the result obtained.

¢'

CAIIOLI

9.1.1 If the room is not completely draft-free, place the lamp in a vertical position in a box constructed of heatresistant material (not containing asbestos), open at the front. The top of the box shall be at least 150 mm above the top of the chimney and the inside of the box painted dull black. 9.2 Extract all wicks, either new or from a previous determination, for at least 25 cycles in an extractor, using a mixture of equal volumes of toluene and anhydrous methanol. Allow the wicks to dry partially in a hood before placing in the oven, or use a forced-draft and explosion-proof oven for drying wicks, or both. Dry for 30 min at 100 to 110*C and store in a dessicator until used.

10. Calibration of Apparatus FIG. 1

Smoke Point Lamp

7.2 2,2,4-trimethylpentane (isooctane), minimum purity 99.75 % (m/m). NOTE 4: Warning--Flammable, vapor harmful. (See Annex A2.2.)

7.3 Methanol (methyl alcohol), anhydrous. NOTE 5: Warning--Flammable, vapor harmful. (See Annex A2.3.)

7.4 Reference Fuel Blends, appropriate to the fuels under test, made up accurately from toluene and 2,2,4trimethylpentane, in accordance with the compositions given in Table 1, by means of calibrated burettes or pipettes. 7.5 Heptane, minimum purity 99.75 % (m/m). TABLE 1

Reference Fuel Blends

Standard Smoke Point at 101.3 kPa

Toluene

2,2,4-trimethylpentane

mm

• (v/v)

% (v/v)

14.7 20.2 22.7 25.8 30.2 35.4 42.8

40 25 20 15 10 5 0

60 75 80 85 90 95 100

10.1 Calibrate the apparatus in accordance with 10.2. Recalibrate at regular intervals of not more than seven days or when there has been a change in the apparatus or operator, or when a change of more than 0.7 kPa occurs in the barometric pressure reading. 10.2 Calibrate the apparatus by testing two of the reference fuel blends specified in 7.4, using the procedure specified in Section 11 and, if possible, bracketing the smoke point of the sample. If this is not possible, use the two test blends having their smoke points nearest to the smoke point of the sample. 10.2.1 Determine the correction f a c t o r f f o r the apparatus from the equation;

f= (As/Aa) + (Bs/Ba) 2

(1)

where: A s = the standard smoke point of the first reference fuel blend; Ad = the smoke point determined for the first reference fuel blend; Bs = the standard smoke point of the second reference fuel blend; Bd = the smoke point determined for the second reference fuel blend. If the smoke point determined for the test fuel exactly 264

~)

D 1322

matches the smoke point determined for a reference fuel blend, use as the second bracketing reference fuel the reference fuel blend with the next higher smoke point, if there is one. Otherwise, use the one with the next closest smoke point. 10.3 An alternative approach to confirm calibration of the apparatus is for each operator to run a control sample each day the apparatus is in use. Record the results and compare the average from the data base of the control sample using control charts or equivalent statistical techniques. If the difference exceeds the control limits or when new apparatus is used, then the apparatus must be recalibrated.

A-Too High

-

B- Correct

C- Too Low

11. Procedure 11.1 Soak a piece of extracted and dried wick, not less than 125 mm long, in the sample and place it in the wick tube of the candle. Carefully ease out any twists arising from this operation. In cases of dispute, or of referee tests, always use a new wick, prepared in the manner specified in 9.2. NOTE 8--It is advisable to resoak the burning-end of the wick in the sample after the wick is inserted in the wick tube. 11.2 Introduce as near to 20 mL of the prepared sample as available, but not less than 10 mL, at room temperature, into the clean, dry candle. 11.3 Place the wick tube in the candle and screw home. Take care that the candle air vent is free from fuel. If a wick-trimmer assembly is not being used, cut the wick horizontally and trim it free of frayed ends so that 6 m m projects from the end of the candle. Use a clean razor blade or other sharp instrument. (Some razor blades have a protective coating; in such cases, remove the coating with a solvent before using the blade). Insert the candle into the lamp. 11.3.1 An alternative method of preparing a wick free of twists and frayed ends utilizes a wick-trimmer assembly. The wick-trimmer holder is inserted over the top of the wick tube and the long-nosed triceps are inserted through the tube and holder. The wick is grasped and carefully pulled through the tube without twisting. A new, clean, sharp razor is used to cut the wick at the face of the holder and remove wisps and frayed ends. When the holder is removed, the wick will be at the correct height in the tube. The tube is then inserted into the candle and screwed home. The candle is inserted into the lamp. 11.4 Light the candle and adjust the wick so that the flame is approximately 10 m m high and allow the lamp to burn for 5 min. Raise the candle until a smoky tail appears, then lower the candle slowly through the following stages of flame appearance: 11.4.1 A long tip; smoke slightly visible; erratic and jumpy flame. 11.4.2 An elongated, pointed tip with the sides of the tip appearing concave upward as shown in Fig. 2 (Flame A). 11.4.3 The pointed tip just disappears, leaving a very slightly blunted flame as shown in Fig. 2 (Hame B). Jagged, erratic, luminous flames are sometimes observed near the true flame tip; these shall be disregarded. l 1.4.4 A well rounded tip as shown in Fig. 2 (Flame C). Determine the height of Flame B to the nearest 0.5 ram. Record the height observed.

[ e ~ - - - Bose of Flame

FIG. 2 Typical Flame Appearances

11.4.4.1 To eliminate errors clue to parallax, the eye of the observer shall be slightly to one side of the centreline, so that a reflected image of the flame is seen on the scale on one side of the central vertical white line, and the flame itself is seen against the other side of the scale. The reading for both observations shall be identical. 11.5 Make three separate observations of the flame height at the smoke point by repeating the flame-appearance sequence specified in 11.4. If these values vary over a range greater than 1.0 mm, repeat the test with a fresh sample and another wick. 11.6 Remove the candle from the lamp, rinse with heptane, and purge with air to make ready for re-use. 12. Calculation 12.1 Calculate the smoke point, to the nearest O. 1 mm, from the equation: smoke point = L x f

(2)

where: L = the average, rounded to the nearest 0.1 mm, of three individual readings, and f = the correction factor (see 10.2), rounded to the nearest 0.01. 12.2 Record the result thus obtained, rounded to the nearest 0.5 mm, as the smoke point of the sample. 265

fJ~) D 1322 13. Precision and Bias6 13.1 Repeatability, r - - T h e difference between successive test results obtained by the same operator with the same apparatus under constant operating conditions on identical material would, in the long run, in the normal and correct operation of the test method, exceed the following value in only one case in 20:

test material would, in the long run, in the normal and correct operation of the test method, exceed the following value in only one case in 20: R = 3 mm (4)

13.2 Reproducibility, R - - T h e difference between two single and independent results obtained by different operators working in different laboratories on nominally identical

NOTE 9--Precision values were determined from a joint ASTM/IP program conducted in 1972. Six referencefuel blends and ten Jet A and Jet B fuels were tested coveting a range of smoke points from 15 to 45 mm. 13.3 Bias--The procedure in Test Method D 1322 for measuring the smoke point of kerosines and aviation turbine fuels has no bias because the value of the smoke point can only be defined in terms of a test method.

6 Supporting data may be obtained from ASTM Headquarters. Request RR:D02-1178.

14. Keywords 14.1 aviation turbine fuel; combustion properties; jet fuel; kerosine; radiant heat; smoke point

r = 2 mm

(3)

ANNEXES

(Mandatory Information) AI. APPARATUS shall have a range of 50 m m graduated in 1 mm intervals, figured at each 10 m m and with longer lines at each 5 mm. AI.1.3 An efficient device for raising or lowering the flame shall be provided. The total distance of travel shall be not less than 10 mm and the movement shall be smooth and regular. A1.1.4 The glass window of the door shall be curved to prevent the formation of multiple images. Al.l.5 The joint between the base of the candle and the candle body shall be oil-tight.

A 1.1 Smoke Point Lamp, 9 as shown in Fig. 1, complying with the dimensional requirements given in Tables A 1.1 and A1.2 and as shown in Figs. AI.I and AI.2. The following essential requirements shall be met: NOTE 10--A medium-density cobalt glass may be used to reduce eye

fatigue when viewingthe flame. A 1.1.1 The top of the wick guide shall be exactly level with the zero mark on the scale. AI.I.2 The scale shall be marked in white lines on black glass on each side of a white or black strip 2 m m in width. It 40ram

[

"J~H

NoTE~Dimeflslonsare millimetres. FIG. A1.1

Lamp Body

266

1

(1~) D 1322 TABLE A1.1

Cdtical Dimensions of Smoke Point Lamp Dimension, mm

Tolerance, mm

Lamp Body (Fig. A1.1)

CandleSocket (c) Internal diameter

23.8

±0.05

Internal diameter Air Inlets (20 in number) (E) Diameter

6.0

±0.02

2.9

±0.05

External diameter Air inlets (20 in number), diameter Lamp Body (G) Internal diameter Internal depth Chimney (H) Internal diameter Height, top of chimney to center of lamp body

35.0 3.5

±0.05 ±0.05

81.0 81.0

¢1.0 ±1.0

40.0 130

±1.0 ±1.0

22rnm

Wick Guide(13)

Gaaery(F)

Candle (Fig. A1.2)

Tim

CendleBody Internal diameter External diameter Length, without cap Thread on cap

W~k Tube(^) Internal diameter External diameter Length Air-Vent (B) Internal diameter Length

21.25 sliding fit in candle'l~der 109 ±0.05 9.5 mm dia screwed 1.0 mm pitch 4.7 +0,05 close fit in flame guide 82.0 ±0.05 3.5 90.0

A

±0.05 ±0.05

9Omm

109mm

J 25mm i

I

~---3.5 mm

FIG. A1.2 Candle

A2. WARNING STATEMENTS A2.1 Toluene A2.1.1 WarningnFlammable. Vapor harmful. Keep away from heat, sparks and open flame. Keep container closed. Use with adequate ventilation. Avoid breathing of vapor or spray mist. Avoid prolonged or repeated skin contact.

adequate ventilation. Avoid build-up of vapors and eliminate all sources of ignition, especially nonexplosion-proof electrical apparatus and heaters. Avoid breathing of vapor or spray mist. Avoid prolonged or repeated skin contact. A2~3 Methanol (Methyl Alcohol) A2.3.1 Warning--Flammable. Vapor harmful. May be fatal or cause blindness if swallowed or inhaled. Cannot be made nonpoisonous. Keep away from heat, sparks and open flame. Keep container closed. Avoid contact with eyes and skin. Avoid breathing of vapor or spray mist. Use with

A2.2 2,2,4-Trimethylpentane (Isooctane) A2.2.1 Warning--Extremely flammable. Harmful if inhaled. Vapor may cause flash fire. Keep away from heat, sparks and open flame. Keep container closed. Use with 267

D 1322 sparks and open flame. Keep container closed. Use with adequate ventilation. Avoid build-up of vapors and eliminate all sources of ignition, especially nonexplosion-proof electrical apparatus and heaters. Avoid breathing of vapor or spray mist. Avoid prolonged or repeated skin contact.

adequate ventilation. Do not take internally. A2.4 Heptane A2.4.1 Warning--Extremely flammable. Harmful if inhaled. Vapor may cause flash fire. Keep away from heat,

APPENDIX

(Nonmandatory Information) Xl. S M O K E P O I N T - L U M I N O M E T E R N U M B E R R E L A T I O N S H I P

XI.I Introduction

ship for aviation turbine fuels of the kerosine type. X 1.1.2 The relationship is based on regression of data on 315 fuels having luminometer numbers falling within the range from - 2 to 100. There were 160 Jet A, A-l, JP-4, and JP-5 fuels in this group. The remaining fuels were diesel fuels, kerosines, blends of refinery fractions, and other miscellaneous petroleum fractions. X 1.1.3 The correlation coefficient was 0.95. X 1.1.4 It can be demonstrated that the confidence intervals about the correlation line is explainable almost completely by the inherent error in the smoke point and luminometer measurements. This means that if there is a fuel-type effect different for each of the two methods, it is small and masked by smoke point and luminometer number measurement errors.

X I. 1.1 There is a good correspondence between smoke point (SP) (Test Method D 1322) and luminometer number (LN) (Test Method D 1740). Figure X I. 1 shows this relation-

35

. . . . .

~r-----r

30 - - - ~

......

r

--7-

. . . . . . . . .

.. . . . . .

--'7

.

.

.

.

I it'

E 25 - - .

...........

I

E

,4- ;S V

LY

i/

t/

.~

20

30

s[ ~'/i lO

-Z ) I

)-.I

.... i

I

--T- ,

-:I

X1.2 Equations XI.2.1 The correlation curve shown in Fig. XI.1 can be represented by either equation as follows: L N = -12.03 + 3.009SP - 0.0104SP2 (XI.I) SP = +4.16 + 0.331LN + 0.000648LN2 (X1.2)

!,

i 40

i 50

Lummometer FIG. X1.1

I- i

I 60

i 70

XI.2.2 The equations are obviously not mathematical identities but yield results that do not differ by more than 0.1 smoke point or luminometer number points. Both equations are presented to facilitate ease of calculation depending on which variable is given.

80

No.

Relationship Between Smoke Point and Luminometer Number

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reepproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at e meeting of the responsible technical committee, which you may attend, ff you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 100 Barr Harbor Drive, West Conshohocken, PA 19428.

268

~8[~

Designation: D 1492 - 96

Standard Test Method for Bromine Index of Aromatic Hydrocarbons by Coulometric Titration 1 This standard is issued under the fixed designation D 1492; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (¢) indicates an editorial change since the last revision or reapproval.

D 3437 Practice for Sampling and Handling Liquid Cyclic Products7 D 3505 Test Method for Density or Relative Density of Pure Liquid Chemicals7 D 4052 Test Method for Density and Relative Density of Liquids by Digital Density Meter6 D5776 Test Method for Bromine Index of Aromatic Hydrocarbons by Electrometric Titration 7 E 29 Practice for Using Significant Digits in Test Data to Determine Conformance with Specificationss 2.2 Other Document: OSHA Regulations, 29 CFR, paragraphs 1910.1000 and 1910.12009

1. Scope 1.1 This test method covers the determination of the amount of bromine-reactive material in aromatic hydrocarbons. It is usually applied to materials having bromine indexes below 500. NOTE l - - O t h e r test m e t h o d s for d e t e r m i n i n g bromine-reactive m a terial are Test M e t h o d s D 1159, D 1491, D 2710, a n d D 5776.

1.2 This test method has been found applicable to aromatic hydrocarbons containing no more than trace amounts ofolefins and that are substantially free from material lighter than isobutane and have a distillation end point under 288"C. 1.3 The following applies to all specified limits in this test method: For purposes of determining conformance with this test method, an observed value or a calculated value shall be rounded off "to the nearest unit" in the last right-hand digit used in expressing the specification limit, in accordance with the rounding-off method of Practice E 29. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For a specific hazard statement see Section 8.

3. Terminology 3.1 Definition: 3.1.1 bromine indexmthe number of milligrams of bromine consumed by 100 g of sample under given conditions.

4. Summary of Test Method 4.1 The specimen is added to a solvent and titrated with electrolytically generated bromine at room temperature. The end point is determined by a dead-stop method. The time of titration is proportional to the bromine added to the specimen.

5. Significance and Use 5.1 This test method is useful for setting specification, for use as an internal quality control tool, and for use in development or research work on industrial aromatic hydrocarbons and related materials. This test method gives a broad indication of olefinic content. It will not differentiate between the types of aliphatic unsaturation.

2. Referenced Documents 2.1 ASTM Standards: D 891 Test Methods for Specific Gravity, Apparent, of Liquid Industrial Chemicals2 D 1159 Test Method for Bromine Number of Petroleum Distillates and Commercial Aliphatic Olefins by Electrometric Titration 3 D 1193 Specification for Reagent Water4 D1491 Test Method for Bromine Index of Aromatic Hydrocarbons by Potentiometric Titration 5 D2710 Test Method for Bromine Index of Petroleum Hydrocarbons by Electrometric Titration6

6. Apparatus 6.1 Amperometric-Coulometric Apparatus, automatic, suitable for bromine index titrations with variable generator current and timer. A typical circuit diagram of suitable equipment is shown in Fig. 1. ~° 6.2 Syringe, 2 mL with needle and rubber cap seal. 6.3 Stirrer, magnetic.

This test method is under the jurisdiction of ASTM Committee D-16 on Aromatic Hydrocarbons and Related Chemicals and is the direct responsibility of Subcommittee DI6.0E on Instrumental Analysis. Current edition approved Dec. 10, 1996. Published February 1997. Originally published as D 1492 - 57 T. Last previous edition D 1492 - 92. 2 Annual Book of ASTM Standards, Vol 15.05. 3 Annual Book of ASTM Standards, Vol 05.01. 4Annual Book of ASTM Standards, Vol 11.01. s Discontinued; see 1985 Annual Book of ASTM Standards, Vol 06.03. Annual Book of ASTM Standards, Vol 05.02.

Annual Book of ASTM Standards, Vol 06.04. 8 Annual Book of ASTM Standards, Voi 14.02. 9 Available from Superintendent of Documents, U.S. Government Printing Office, Washington, I)(2 20402. to The sole source of supply of the apparatus known to the committee at this time is Refinery Supply Co., 6901 E 12th St. Tulsa, OK 74112. lfyou are aware of alternative suppliers, please provide this information to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, ~ which you may attend.

269

11~ D 1492 MILLIAMETER

TIMER

II~VAG

~'~

GTIRRING MAGNET

FIG. 1

Automatic Amperometric-Coulometdc Titrator Circuit

7. Reagents

TABLE 1 Specimen Size and Generation Current Estimated Specimen Weight, Generation Bromine Index g Current, mA 0 to 20 1.000 1.0 20 to 200 0,600 5.0 200 to 2000 0.060 5.0

7.1 Purity of Reagent--Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, where such specifications are available. == Other grades may be used, provided it is fast ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination. 7.2 Purity of Water--Unless otherwise indicated, references to water shall be understood to mean reagent water conforming to Type IV of Specification D 1193. 7.3 Electrolyte--To make 1 L, mix 600 mL of glacial acetic acid, 260 mL of absolute methanol, and 140 mL of KBr solution (119 g/L). Dissolve 2 g of Mercury II acetate in this mixture. 7.4 Potassium Bromide Solution (119 g/L)--Dissolve 119 g of potassium bromide (KBr) in water and dilute to 1 L.

rial Safety Data Sheets, and local regulations for all materials used in this test method.

9. Sampling 9.1 Sample the material in accordance with Practice D 3437. 10. Procedure 10.1 Place 50 mL of electrolyte in a clean, dry titration cell, insert the electrodes, and begin stirring. Apply the generation current in accordance with Table 1. 10.2 Before introducing the specimen and immediately before each determination, bring the coulometer to equilibrium. 10.3 Draw into the syringe the amount of sample prescribed in Table 1 corresponding to the estimated bromine index. Wipe the needle with a clean cloth, attach a rubber cap seal to the needle, and weigh on the analytical balance. Remove the seal, add the specimen to the electrolyte, and set the timer to zero. Replace the seal, reweigh the syringe, and

8. Hazards 8.1 Consult current OSHA regulations, supplier's Mate11 "Reagent Chemicals, American Chemical Society Specifications," Am. Chem. Soe., Washington, DC. For suggestions on the testing of reagents not listed by the American Chemical Society, see "Reagent Chemicals and Standards," by Joseph Rosin, D. Van Nostrand Co., Inc., New York, NY, and the "United States Pharmacopeia."

270

({@) D 1492 calculate the specimen weight. NOTE 2--If the density or specificgravity of the specimen is known (Test Methods D 891, D 3505, or D4052 can be used), the specimen can be added by means of a pipet or microburet and the weight calculated.

12. Report 12.1 Report the following information: 12.1.1 Report bromine index to the nearest unit.

where:

13. Precision and Bias 13.1 Precision data were generated using titrators from Central Scientific Co. The precision obtained using titrators from other suppliers has not been determined. 13.2 Precision--The following data should be used for judging the acceptability of results (95 % probability) for bromine indexes from 0 to 50: 13.2. l Intermediate Precision (formerly called Repeatability)--The standard deviation is 0.39. Duplicate results by the same operator should be considered suspect if results differ by more than 1.15. NOTE 3--Number of data used, 91; number of degrees of freedom, 61; number of cooperating laboratories, 4. 13.2.2 Reproducibility--The standard deviation is 1.43. The results submitted by two laboratories should be considered suspect if they differ by more than 4. I. NOTE 4nNumber of data used, 41; number of degrees of freedom, 30; number of cooperating laboratories, 4. 13.3 Bias--The procedure in this test method has no bias because the value of bromine index can be defined only in terms of a test method.

T ffi titration time, s, I ffi generation current, mA, and W = weight of specimen, g.

14. Keywords 14.1 aromatic hydrocarbons; bromine index; brominereactive; coulometric titration; titration

10.4 Begin titration of the specimen. As the titration proceeds, keep the generation current at the selected value. The generation of bromine will continue as long as it is consumed by the sample. At the end point an incremental increase in bromine concentration causes the titrator and timer to stop automatically. Forty seconds after the titrator has shut off, continue the titration. If the titrator cuts off, immediately, the end point has been reached and the titration may be considered complete. Otherwise, it may be necessary to continue the titration in steps, waiting about 40 s between steps, until the titration time increment is 4 s or less. Note the total titration time and generation current. 11. Calculation 11.1 Calculate the bromine index, B, as follows:

TI x 79.9

B-----

965W

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, ere entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and ff not revised, either reapproved or withdrawn. Your comments ere invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend, ff you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 100 Barr Harbor Drive, West Conshohockan, PA 19428.

271

~

AnAmencanNationalStandard

Designation; D 1552 - 95

Standard Test Method for Sulfur in Petroleum Products (High-Temperature Method) 1 This standard is issued under the fixed designation D 1552; the number immediately following the designation indicates the year of original adoption or, in the ease of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (0 indicates an editorial change since the last revision or reapproval.

This test method has been approved for use by agencies of the Department of Defense and for listing in the DOD Index of Specifications and Standards.

special ceramic boat which is then placed into a combustion furnace at 137 I*C (2500"F) in an oxygen atmosphere. Most sulfur present is combusted to SO2 which is then measured with an infrared detector after moisture and dust are removed by traps. A microprocessor calculates the mass percent sulfur from the sample weight, the integrated detector signal and a predetermined calibration factor. Both the sample identification number and mass percent sulfur are then printed out. The calibration factor is determined using standards approximating the material to be analyzed.

1. Scope 1.1 This test method covers three procedures for the determination of total sulfur in petroleum products including lubricating oils containing additives, and in additive concentrates. This test method is applicable to samples boiling above 177"C (350"F) and containing not less than 0.06 mass % sulfur. Two of the three procedures use iodate detection; one employing an induction furnace for pyrolysis, the other a resistance furnace. The third procedure uses IR detection following pyrolysis in a resistance furnace. 1.2 Petroleum coke containing up to 8 mass % sulfur can be analyzed. 1.3 This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

4. Significance and Use 4.1 This test method provides a means of monitoring the sulfur level of various petroleum products and additives. This knowledge can be used to predict performance, handling, or processing properties. In some cases the presence of sulfur compounds is beneficial to the product and monitoring the depletion of sulfur can provide useful information. In other cases the presence of sulfur compounds is detrimental to the processing or use of the product.

2. Referenced Documents 2.1 A S T M Standards: D 1193 Specification for Reagent Water2 D 1266 Test Method for Sulfur in Petroleum Products (Lamp Method) 3 D4057 Practice for Manual Sampling of Petroleum and Petroleum Products4

5. Interferences 5.1 For the iodate systems, chlorine in concentrations less than 1 mass % does not interfere. The IR system can tolerate somewhat higher concentrations. Nitrogen when present in excess of 0.1 mass % may interfere with the iodate systems; the extent of such interference may be dependent on the type of nitrogen compound as well as the combustion conditions. Nitrogen does not interfere with the IR system. The alkali and alkaline earth metals, as well as zinc, phosphorus, and lead, do not interfere with either system.

3. Summary of Test Method 3.1 lodate Detection SystemmThe sample is burned in a stream of oxygen at a sufficiently high temperature to convert about 97 % of the sulfur to sulfur dioxide. A standardization factor is employed to obtain accurate results. The combustion products are passed into an absorber containing an acid solution of potassium iodide and starch indicator. A faint blue color is developed in the absorber solution by the addition of standard potassium iodate solution. As combustion proceeds, bleaching the blue color, more iodate is added. The amount of standard iodate consumed during the combustion is a measure of the sulfur content of the sample. 3.2 IR Detection System--The sample is weighed into a

6. Apparatus 6.1 Combustion and lodate Detection System 6.1.1 FurnacesmTwo major types are available, the primary difference being the manner in which the necessary high temperatures are obtained. These two types are as follows: 6.1.1.1 Induction Type, which depends upon the highfrequency electrical induction method of heating. This assembly shall be capable of attaining a temperature of at least 1482"C (2700"F) in the sample combustion zone, under the conditions set forth in Section 10 and shall be equipped with an additional induction coil located above the combustion zone, substantially as shown in Fig. I. 6.1.1.2 The furnace work coil should have a minimum output of 500 W; the minimum input rating of the furnace must be 1000 W. With the correct amount of iron chips,

~This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee I)02.03 on Elemental Analysis. Current edition approved Aug. 15, 1995. Published October 1995. Originally published as D 1552 - 58 T. Last previous edition D 1552 - 90. 2 Annual Book of ASTM Standards, Vol I 1.01. 3 Annual Book of ASTM Standards, Vol 05.01. 4 Anmzal Book of ASTM Standards, Vol 05.02.

272

~

D 1552

weighed to +0.05 g, the maximum plate current will be between 350 and 450 mA. NOTE 1: Warning--This type of furnace is capable of inflicting high-

frequency burns and high-voltage shocks. In addition to other precautions, maintain all guards properly. Precaution--Disconnect the furnace from the power line wheneverelectricalrepairs or adjustments are made.

$~ondory tteoter Coil

6.1.1.3 Resistance Type, capable of maintaining a temperature of at least 137 I*C (2500"F). 6.1.2 Absorber, as described in Test Method D 1266.

I fa- ~

t

~,$econdory H e o / e r -/~

Prlmory

NOTE 2--Also suitable for use with either type of furnace is an automatic titrator, specificallydesigned for iodometry. This combines the functions of absorption and titration to a predetermined end point.

6.1.3 Buret, standard 25-mL or automatic types available from the manufacturers of the specific combustion units, are suitable (Note 2). 6.2 Combustion and IR Detection System, comprised of automatic balance, oxygen flow controls, drying tubes, combustion furnace, infrared detector and microprocessor. The furnace shall be capable of maintaining a nominal operating temperature of 1350"C (2460"F). 5 6.3 Miscellaneous Apparatus--Specific combustion assemblies require additional equipment such as crucibles, combustion boats, crucible lids, boat pushers, separator disks, combustion tubes, sample inserters, oxygen flow indicator, and oxygen drying trains. The additional equipment required is dependent on the type of furnace used and is available from the manufacturer of the specific combustion unit. To attain the lower sulfur concentration given in Section 1, the ceramics used with the induction furnace assembly shall be ignited in a muffle furnace at 1371"C (2500"F) for at least 4 h before use. 6.4 Sieve, 60-mesh (250-mm).

FIG. 1

concentrated hydrochloric acid (HCI, relative density 1.19) to 2 L with water. NOTE 4: Warning--Poison. Corrosive. May be fatal if swallowed.

Liquid and vapor cause severe burns. 7.6 Oxygen (Extra Dry)--The oxygen shall be at least 99.5 % pure and show no detectable sulfur by blank determination. NOTE 5: Warning--Oxygen vigorouslyacceleratescombustion. 7.7 Phosphorus Pentoxide (P205). 7.8 Potassium Alum (Aluminum Potassium Sulfate). 7.9 Potassium Iodate, Standard Solution (0.06238 M, 1 mL = 1 mg S)--Dissolve 2.225 g of potassium iodate (KIO3) that has been dried at about 180"C to constant weight, in water and dilute to 1 L. Thoroughly mix the solution. 7. I0 Potassium Iodate, Standard Solution (0.006238 M, 1 mL = 0.1 mg S)--Measure exactly 100 mL of KIO 3 solution (0.06238 M, 1 m L = 1 mg S) into a I-L volumetric flask, and dilute to volume with water. Thoroughly mix the solution. 7.11 Potassium Iodate, Standard Solution (0.01248 M, 1 mL = 0.2 mg S)--Measure exactly 200 m L of KIO 3 solution (0.06238 M, I mL = 1 mg S) into a I-L volumetric flask and dilute to volume with water. Thoroughly mix the solution. 7.12 Ascarite, 8 to 20 mesh.

7. Reagents and Materials

7.1 Purity of Reagents--Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, where such specifications are available. 6 Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination. 7.2 Purity of Water--Unless otherwise indicated, references to water shall be understood to mean reagent water as defined by Type II or III of Specification D 1193. 7.3 Alundum (A1203) or Magnesium Oxide (Com-Aid). 7.4 Anhydrone (Magnesium Perchlorate).

7.13 Special Materials for Induction-Type Furnaces: 7.13.1 Tin (20 to 30-mesh). 7.13.2 Iron-Chip Accelerator having a sulfur content of

NOTE 3: Precaution--In addition to other precautions, handle magnesium perchlorate with care. Avoid contacting it with acid and organic materials. Reactions with fuel may be violent.

7.5 Hydrochloric Acid (3 +

Combustion Tube

197)--Dilute 30 mL of

s The Models SC32, or SC132, manufactured by LECO Corporation, 3800 Lakeview Avenue, St. Joseph, M149085-2396, have been found satisfactory for this purpose. 6"Reagent Chemicals; American Chemical Society Specifications," Am. Chemical Soc., Washington, DC. For suggestions on the testings.of reagents not listed by the American Chemical Society, see "Reagent Chemicals and Standards," by Joseph Rosin, D. Van Nostrand Co., Inc., New York, NY, and the "United States Pharmacopeia."

not more than 0.005 mass %. 7.14 Standard Sample--Potassium alum (A1K(SO4)2. 12H20). 7.15 Starch-Iodide Solution--Make a paste by adding 9 g of soluble starch to 15 mL of water. Add this mixture, with stirring, to 500 mL of boiling water. Cool the mixture, add 15 g of potassium iodide (KI), and dilute to 1 L with water. 7.16 Sulfuric Acid (relative density 1.84)~Concentrated sulfuric acid (H2SO4). NOTE 6: Warning--Poison. Corrosive. Strong oxidizer. 7.17 Vanadium Pentoxide, anhydrous, powdered V205. 8. Sampling

8.1 Take samples in accordance with the instructions in Practice D 4057. 273

(~ D 1552 9. Preparation of Apparatus 9.1 Induction-Type FurnacenAssemble the apparatus according to the instructions furnished by the manufacturer. Purify the oxygen by passing it through (1) H2SO4 (relative density 1.84), (2) Ascarite, and (3) magnesium perchlorate (Mg(CIO4)2) or phosphorus pentoxide (P205) (Precautionn see Note 3). Connect a rotameter between the purifying train and the furnace. Insert a small glass-wool plug in the upper end of the glass tubing connecting the furnace with the absorber to catch oxides of tin. Connect the exit end of the combustion tube to the absorber with glass tubing, using gum rubber tubing to make connections. Position the absorber so as to make this delivery line as short as possible. Figure 2 illustrates schematically the assembled apparatus. Adjust the oxygen flow to 1 _+ 0.05 L/min. Add 65 mL of HCI (3 + 197) and 2 mL of starch-iodide solution to the absorber. Add a sufficient amount of the appropriate standard KIO3 solution (Table 1) to produce a faint blue color. This color will serve as the end point for the titration. Adjust the buret to zero. Turn on the furnace filament switch and allow at least 1 rain warm-up before running samples (Precaution--see Note 3). 9.2 Resistance-Type Furnace--Assemble the apparatus according to the instructions furnished by the manufacturer. Purify the oxygen by passing it through (1) H2SO4 (relative density 1.84), (2) Ascarite, and (3) Mg(CIO4)2 or P205 (Precaution--see Note 3). Connect a rotameter between the purifying train and the furnace. Figure 3 illustrates schematically the assembled apparatus. Turn on the current and adjust the furnace control to maintain a constant temperature of 1316 + 14"C (2400 + 25"F). Adjust the oxygen flow rate to 2 + 0.1 L/rain. Add 65 mL of HCl (3 + 197) and 2 mL of starch-iodide solution to the absorber. Add a few drops of the appropriate standard KIO3 solution (Table 2) to produce a faint blue color. Adjust the buret to zero. 9.3 Resistance-Type Furnace-lR Detection~Assemble and adjust apparatus according to manufacturer's instructions. Initialize microprocessor, check power supplies, set oxygen pressure and flows and set furnace temperature to 137 I*C (2500"F). 9.3.1 Condition a fresh anhydrone scrubber with four coal samples. 9.3.2 Calibrate ',he automatic balance according to manufacturer's instructions. 10. Standardization 10.1 For Iodate Methods: 10.1.1 Determination of Alum Factor." 10.1.1.1 Because these rapid combustion methods involve Induction Furnoce

U

FIG. 2

TABLE 1

Sample Weight for Induction Furnace

Sulfur Content, %

Weight of Sample to be Taken, mg

Normalityof Standard KIOa solution for Titration

0 to 2 2 to 4 4 to 10 Over 10

90A 50 to 90 50 to 90 12.1.1

0.006238 0.006238 0.01248 (Note 7)

A Approximate.

the reversible reaction 2802 + 02 = 2SO3, it is not possible to evolve all the sulfur as SO2. The equilibrium of the reaction is temperature dependent and, in an oxygen atmosphere above 1316"C, about 97 % of the sulfur is present as SO2. To assure that the furnace is in proper adjustment and that its operation produces acceptably high temperature, potassium alum is employed for standardizing the apparatus. Depending on the type of combustion equipment used, proceed as described in Sections l0 to 13 to determine the alum factor. Use 15 mg weighed to +0. l mg of potassium alum for this determination. Use the same materials in the determination of the alum and standardization factors as for the unknown samples. For example, V20 s has a definite effect and should be included if used for unknowns as recommended in the procedure with the resistance-type furnace (Note 10). 10.1.1.2 Calculate the alum factor as follows: Alum factor (AF) -- (SA x WA)/(IOO(Va - Vb) x C~) (l) where: sA = mass percent sulfur in potassium alum used, wA= milligrams of potassium alum used, vo = millilitres of standard KIO 3 solution used in determining the alum factor, v~ = millilitres of standard KIO3 solution used in the blank determination, and C I = sulfur equivalent of the standard K/O 3 solution used in determining the alum factor, mg/mL. 10.1.1.3 The alum factor should be in the range from 1.02 to 1.08. If values smaller than 1.02 are observed, confirm independently the sulfur content of the alum and the sulfur equivalent of the KIO3 solution before repeating the alum factor determination. If values larger than 1.08 are observed, make adjustments in the equipment in accordance with the manufacturer's recommendation and repeat the alum factor determination. 10.1.2 Determination of Standardization Factor: 10.1.2.1 Because effects such as sample volatility can also affect the relative recovery as SO2 of the sulfur originally present in the sample, it is necessary to determine a standardization factor. Proceed as described in Sections 10 to 13, using an oil sample of similar type to the unknown sample and of accurately known sulfur content. 7 10.1.2.2 For IR detection, determine and load the microprocessor with the calibration factor for the particular type of sample to be analyzed (lubricating oil, petroleum coke, residual fuel) as recommended by the manufacturer. 10.1.2.3 Calculate the standardization factor as follows: Standardization factor (Fs) -- (Ss x Ws)/(100 (V~ - Vb) X C) (2)

Oxygen Residual fuel oil Standard Reference Materials may be obtained from the National Institute of Standards and Technology or other sources.

Schematic Illustration of Induction-Type Furnace

274

(~ D 1552 I~

TABLE 2

BURET

•RO'I~talETE R

Sulfur Content, %

Weight of S a m p l e to be Taken, mg

Normalityof Standard KIOa solutionfor Titration

0 to 2 2 to 5 5 to 10 Over 10

100 to 200 100 to 200 100 to 200 (Note 7)

0.006238 0.01248 0.06238 (Note 7)

~1 md,l,,,c. A|SORBER

FIG. 3

Schematic Illustration of Resistance-Type Furnace

where: ss

=

mass percent sulfur in standardization sample used,

w s = milligrams of standardization sample used, millilitres of standard KIO3 solution used in the blank determination, Vs = millilitres of standard KIO3 solution used in determining the standardization factor, and C = sulfur equivalent of the standard KIO3 solution used in determining the standardization factor, mg/mL. 10.1.3 Quality Control--Run a suitable analytical quality control sample several times daily. When the observed value lies between acceptable limits on a quality control chart, proceed with sample determinations. ve

=

11. Preparation of Coke 11.1 It is assumed that a representative sample has been received for analysis. 11.2 Grind and sieve the sample received so as to pass a 60-mesh (250-ram) sieve. 11.3 Dry the sieved material to constant weight at 105 to 110*C. 12. Procedure with Induction-Type Furnace 12.1 Sample Preparation--Add a 3.2 to 4.8-mm (1/8 to 3A6-in.) layer of alundum or magnesium oxide to a sample crucible. Make a depression in the bed with the end of a stirring rod. Weigh the crucible to 0.1 mg. Weigh into the depression the proper amount of sample according to Table 1 (12.1.1) (Note 7). Cover the sample with a separator disk (Note 8). Place on the separator disk the predetermined amount of iron chips necessary to obtain the required temperature (6.1.1.2). This is usually between 1.2 and 2.0 g, but should be held constant with +0.05 g. Sprinkle about 0.1 g of tin on the iron. Cover the crucible with a lid and place on the furnace pedestal. 12.1.1 Under no conditions shall an organic sample larger than 100 mg be burned in an induction-type furnace.

Sample Weight for Resistance Furnace

discard the determination. Make KIO 3 additions as the rate of evolution of SO2 diminishes such that, when combustion is completed, the intensity of the blue color is the same as the initial intensity. Combustion is complete when this color remains for at least 1 rain and the plate current has dropped considerably. Record the volume of KIO 3 solution required to titrate the SO2 evolved. 12.3 Blank Determination--Make a blank determination whenever a new supply of crucibles, materials, or reagents is used. Follow the preceding procedure, but omit the sample. 13. Procedure with Resistance-Type Furnace 13.1 Sample Preparation--Weigh into a combustion boat the proper amount of sample according to Table 2 (Footnote 8). Add 100 + 5 mg of vanadium pentoxide and completely cover the mixture with Alundum. 13.2 Combustion and Titration--Place the boat in the cool portion of the combustion tube, near the entrance. To proceed with the combustion, push the boat containing the sample progressively into the hotter zone of the combustion tube using the equipment provided by the manufacturers. The boat should be advanced as rapidly as possible consistent with the rate of evolution of SO2. Add the appropriate standard KIO3 solution (Table 2) to the absorber to maintain the blue color. Should the absorber solution become completely colorless, discard the determination. Make KIO3 additions as the rate of evolution of SO2 diminishes such that, when combustion is completed, the intensity of the blue color is the same as the initial intensity. Combustion is complete when this color remains for at least 1 min. Record the volume of KIO3 solution required to titrate the SO2 evolved. 13.3 Blank Determination--Make a blank determination whenever a new supply of combustion boats, materials, or reagents is used. Follow the above procedure, but omit the sample. 14. Procedure with Resistance Furnace-IR Detection 14.1 Allow the system to warm up and the furnace to reach operating temperature. 14.2 After homogeneity of the sample is assured, select the sample size as follows: for liquid samples, take up to 0.13 g for analysis and for solid samples, take up to 0.4 g for analysis. In each case mass percent sulfur times weight of sample must be less than or equal to four in the case of the SC32 instrument, and two in the case of the SC132 instrument. For other instruments, consult the manufacturer's instructions. 14.3 Determine and store the system blank value.

NOTE 7--More concentrated KIO3 solutions, such as the 0.06238 N solution, may be found more convenient for samples containing more than 10 % sulfur. The sample size and KIO3 concentration should be chosen so that not more than 25 mL of titrant are needed. NOTE 8--The use of the separator disk is optional.

12.2 Combustion and Titration--Turn on the plate current switch. After about 1 rain for warm-up, raise the pedestal and lock into position. The plate current will fluctuate for a few seconds and should graduall~~rise to a maximum value. Add the appropriate standard KIO 3 solution (Table 1) to the absorber to maintain the blue color. Should the absorber solution become completely colorless,

s Precision for the IR detection method was determined in a 1985 cooperative study (RR: D02-1231) which involved fourteen laboratories and ten samples. No statistically significant bias between the iodate and IR detector procedures was found.

275

(~ D 1552 17.1.1 Repeatability--The difference between two test results obtained by the same operator with the same apparatus under constant operating conditions on identical test material would, in the long run, in the normal and correct operation of the test method, exceed the following values in only one case in twenty:

14.4 Weigh the samples into combustion boats and record the net weights. It is possible to weigh and store several weights in the microprocessor before beginning a series of burns. 14.4.1 Fill the combustion boat to one-third capacity with evenly spread MgO powder. 14.4.2 Form a slight trench in the MgO powder with a

Repeatability

scoop. 14.4.3 Place the combustion boat on the balance and

weigh an appropriate amount of the sample into the trench in the MgO powder. Enter the weight. 14.4.4 Remove the combustion boat from the balance and add MgO powder until the combustion boat is filled to two-thirds capacity. NOTE 9--If unacceptable repeatability is encountered for particular oil samples, combustion promoter such as V205 or the LECO product Corn-Aidcan be substituted for the MgO. NOTE 10~Caution--V205 can cause deterioration of the furnace ceramics so use it with care. 14.5 Initiate oxygen flow and load boat into furnace. 14.6 When the analysis is complete, read the result from the microprocessor. 14.7 Remove the expended combustion boat from the furnace. 14.8 Make repeated runs until two results differ by less than the repeatability of the method.

Sulfur, mass-% Range

Iodate

1Ra

0.0 to 0.5 0.5 to 1.0 1.0 to 2.0 2,0 to 3.0 3.0 to 4.0 4.0 to 5.0

0.05 0.07 0.10 0.16 0.22 0.24

0.04 0.07 0.09 0.12 0.13 0.16

17.1.2 Reproducibifity--The difference between two single and independent results obtained by different operators working in different laboratories on identical test material would, in the long run, in the normal and correct operation of the test method, exceed the following values in only one case in twenty: Reproducibility Sulfur, mass-% Range 0.0 to 0.5 to 1.0 to 2.0 to 3.0 to 4.0 to

15. Calculation 15.1 Calculation for Iodate Detection--Calculate the sulfur content of the sample as follows: Sulfur, mass % = (100 (V - Vb) × Fs x C)/W (3) where: I/ ___ standard KIO3 solution, mL, used in the analysis, Vb = standard KIO3 solution, mL, used in the blank determination, Fs = standardization factor (see 10.1.2), C = sulfur equivalent of the standard K/O3 solution used in the analysis, mg/mL, and W = milligrams of sample used in the analysis. 15.2 Calculationfor IR Detection: 15.2.1 Report all results using the microprocessor. 15.2.2 Report the average of two results.

0.5 1.0 2.0 3.0 4.0 5.0

lodate

IR a

0.08 0.11 0.17 0.26 0.40 0.54

0,13 0.21 0.27 0.38 0.44 0.49

17.2 For Petroleum Cokes by Iodate and IR Methods-The precision of the test method as determined by statistical examination of interlaboratory results is as follows: 17.2.1 Repeatability--The difference between two test results obtained by the same operator with the same apparatus under constant operating conditions on identical test material would, in the long run, in the normal and correct operation of the test method, exceed the following values in only one case in twenty: r = 0.05X where X is the average of the two test results. 17.2.2 Reproducibility--The difference between two single and independent results obtained by different operators working in different laboratories on identical test material could, in the long run, in the normal and correct operation of the test method, exceed the following values in only one case in twenty: R = 0.22X where X is the average of the two test results. 17.3 Bias--The bias of the procedure in this test method is being determined.

16. Report 16.1 In the range from 0.05 to 5.00 mass % sulfur, report to the nearest 0.01 mass %. In the range from 5 to 30 mass % sulfur, report to the nearest 0.1 mass %. 17. Precision and Bias 17.1 For Petroleum Products by Iodate and IR Methods-The precision of this test method as determined by statistical examination of interlaboratory results is as follows:

18. Keywords 18.1 furnace; high temperature; induction furnace; iodate titration; IR detection; petroleum; resistance; sulfur; titration

The American Society for Testing and Materials takes no position respecting the vahdtty of any patent rights asserted m connection wtth any item menhoned in this standard Users o/th~s standard are expressly adwsed that determination of the vahdtty of any such patent rights, and the risk of infringement ol such rights, are entirely their own responslbthty Th~s stand2rd is sublect to revision at any time by the responsible technical committee and must be reviewed every bye years and if not revised, either reapproved or withdrawn Your comments are inwted either for rewston of this standard or for add~honal standards and should be addressed to ASTM Headquarters Your comments wdl receive careful consideration at a meeting of the responsible techmcal committee, which you may attend If you feel that ;,our comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 100 Barr H~rbor Drive, West Conshohocken, PA 19428

276

(~~,) Designation: D 1685 - 95 Standard Test Method for Traces of Thiophene in Benzene by Spectrophotometry 1 This standard is issued under the fixed designation D 1685; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (~) indicates an editorial change since the last revision or reapproval.

1. Scope 1.1 This test method covers the determination of thiophene in benzene in which the thiophene concentration is between 0.1 and 250 mg/kg. 1.2 Contaminating materials that are darkened by sulfuric acid interfere and must be compensated for by a sample blank determination. Neither carbon disulfide in concentrations as high as 100 mg/kg nor water as high as the level of saturation will interfere. 1.3 Contaminating materials may occasionally cause the color development in this test method to be time dependent and may also contribute to spectral interferences at 589 nm. Consequently, test results indicating substantial thiophene, that cannot be verified by total sulfur analysis, should be considered suspect. 1.4 The following applies to all specified limits in this standard: for purposes of determining conformance with this standard, an observed value or a calculated value shall be round off "to the nearest unit" in the last right-hand digit used in expressing the specification limit, in accordance with the round-off method of Practice E 29. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard sIatements, see Note 1, 7.1, and 8.1.

3. Summary of Test Method 3.1 Thiophene is reacted with isatin, under prescribed conditions, to form a colored compound. The compound is extracted into sulfuric acid, and the intensity of the color is measured spectrophotometrically. Thiophene concentration is obtained by correlation with knowns. 4. Significance and Use 4.1 This test method is suitable for setting specifications on benzene and for use as an internal quality control tool where benzene is either produced or used in a manufacturing process. It may also be used in development or research work involving benzene. 5. Apparatus

5.1 Separatory Funnels, 50, 250, 500, and 1000-mL, with glass stoppers. 5.2 Spectrophotometer--Any spectrophotometer may be used that is capable of repeatability of 0.005 absorbance units in the range from 0.1 to 1.4 absorbance and repeatability of wavelength of 1 nm in the i'egion from 400 to 700 rim.

5.3 Absorption Cells, l-cm, matched, glass or silica. 5.4 Analytical Balance. 5.5 Pipets, 1, 2, 5, and 10-mL. 5.6 Graduated Cylinders, 250 and 1000-mL. 5.7 Volumetric Flasks, glass-stoppered, 50, 100, 250, and 1000-mL. 5.8 Filter Paper, medium filter6 and rapid hardened. 7

2. Referenced Documents

6. Reagents 6.1 Purity of Reagents--Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, where such specifications are available) Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination. 6.2 Purity of Water--Unless otherwise indicated, references to water shall be understood to mean Type IV reagent water conforming to Specification D 1193. 6.3 Cadmium Chloride Solution (20 g/L)--Dissolve 20 g

2.1 A S T M Standards: D 1193 Specification for Reagent Water 2 D 3437 Practice for Sampling and Handling Liquid Cyclic Products 3 E 29 Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications4

2.2 Other Document: OSHA Regulations, 29 CFR, paragraphs 1910.1000 and 1910.12005 J This test method is under the jurisdiction of ASTM Committee D-16 on Aromatic Hydrocarbons and Related Chemicals and is the direct responsibility of Subcommittee DI6.0A on Benzene, Toluene, Xylene, Cyclohexane, and Their Derivatives. Current edition approved April 15, 1995. Published June 1995. Originally published as D 1685 - 58 T. Last previous edition D 1685 - 86 (1990). 2 Annual Book of ASTM Standards, Vol 11.01. 3 Annual Book of ASTM Standards, Vol 06.04. 4 Annual Book of ASTM Standards, Vol 14.02. s Available from Superintendent of Documents, U.S. Government Printing Office, Washington, DC 20402.

6 This method is based on the use of Whatman 1. 7 This method is based on the use of Whatman 54.

s Reagent Chemicals, American Chemical Society Specifications, American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed by the American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville, MD.

277

(t~ D 1685 of anhydrous cadmium chloride (CdCI2) or 25 g of cadmium chloride hydrate (CdC12"2Jh H20) in 200 mL of water and dilute to 1 L. 6.4 Su~tric Acid (sp gr 1.84)--Concentrated H 2 S O 4. 6.5 Benzene, Thiophene-Free: 6.5.1 Wash 700 mL of benzene in a 1000-mL separatory funnel with successive 100-mL portions of concentrated sulfuric acid ( H 2 8 0 4 ) to which has been added 5 mL of isatin solution, until the H2SO4 layer is light yellow or colorless. Wash the benzene with 100 mL of water and then twice with 100 mL of cadmium chloride solution (CdC12). Finally, wash with another 100-mL portion of water. Filter the benzene through medium filter paper into a storage bottle and tightly stopper. 6.5.2 Prepare 1400 mL of thiophene-free benzene. Measure the absorbance of this material by the procedure outlined in 10.2 and 11.2. The absorbance should be no greater than 0.01. 6.6 Ferric Sulfate, Sulfuric Acid Solution--Add 0.2 g of ferric sulfate ( F e 2 ( 8 0 4 ) 3 ° 9H20) together with 38 mL of water to a I-L volumetric flask. Swirl to dissolve. Cautiously add about 100 mL of H2SOa and swirl. Allow time for the heat of reaction to subside and dilute to volume with H2SO4.

flask containing the first extract. Dilute to volume with H 2 S O 4 and mix. This blank is stable for 8 h and need not be repeated with each analysis during this period. 9.2 Reagent Blank 2--Into a 50-mL volumetric flask, pipet 10 mL of ferric sulfate-sulfuric acid solution and dilute to volume with H2SO4. Stopper and mix. This blank is stable for 8 h and need not be repeated with each analysis during this period. 9.3 Sample Blank--Take a 100-mL portion of the CdCI2 washed and filtered benzene sample (prepared in accordance with the procedure in 11.1). Transfer to a 250-mL separatory funnel. Add 10 mL of ferric sulfate-sulfuric acid solution, stopper, and shake for 2 min + 15 s. Allow the two phases to separate and draw off the lower H 2 S O 4 layer into a 50-mL volumetric flask. Add 10 mL of H2SO, to the separatory funnel and shake for 30 + 5 s. Again draw off the lower H2SO4 layer into the 50-mL volumetric flask containing the first extract. Dilute to volume and mix. Repeat with each specimen.

10. Preparation of Calibration Curves 10.1 Add approximately 0.2 g of thiophene, weighed to the nearest 0.0002 g to a 100-mL volumetric flask containing about 50 mL of thiophene-free benzene. Dilute to volume with thiophene-free benzene and mix. This is Solution 1. Pipet 1 mL of Solution 1 into a 100-mL volumetric flask, dilute to volume with thiophene-free benzene, stopper, and mix. This is Solution 2 and will contain approximately 20 p.g of thiophene per millilitre. 10.2 Pipet 0, 1, 2, 5, 7, and 10-mL of Solution 2 into 100-mL volumetric flasks and dilute to volume with thiophene-free benzene. Transfer to 500-mL separatory funnels and follow the procedure in 11.2 and 11.3 for ea.ch concentration. Plot absorbance versus concentration in micrograms per millilitre. 10.3 Prepare Solution 3 containing approximately 40 p.g of thiophene per millilitre by pipetting 2 mL of Solution 1 into a 100-mL volumetric flask and diluting to volume with thiophene-free benzene. Follow the procedure in 10.2 to obtain the calibration curve for 50-mL specimens.

NOTE 1: Precaution--Protective clothing and goggles should be worn whenever H2SO 4 is used.

6.7 Isatin, Chloroform, Benzene Solution--Add 0.5 g of isatin to 200 mL of chloroform. Heat, in a fume hood, to a temperature just below the boiling point (6 l'C) of chloroform and maintain for 5 min with stirring. Filter into a 250-mL volumetric flask through hardened rapid filter paper. Wash the filter paper with two 20-mL portions of thiophene-free benzene (from 6.5) eluting the washings into the volumetric flask. Dilute to volume with thiophene-free benzene. 6.8 Thiophene. 9

7. Hazards 7.1 Consult current OSHA regulations and supplier's Material Safety Data Sheets for all materials used in this test method. 8. Sampling 8.1 Sampling of benzene should follow safe rules in order to adhere to all safety precautions as outlined in the latest OSHA regulations. Refer to Practice D 3437 for proper sampling and handling of benzene. 9. Preparation of Reagent Blanks and Sample Blank 9.1 Reagent Blank / - - T o a 50-mL separatory funnel pipet 5 mL of isatin solution and 10 mL of ferric sulfatesulfuric acid solution. Stopper and shake for 2 min _+ 15 s. The shaking is accomplished by wrist action in a rocking motion through a 180" arc roughly once each second. Allow the two phases to separate and draw off the lower H2SO4 layer into a 50-mL volumetric flask. Add 10 mL of H2SO4 to the separatory funnel, stopper, and shake for 30 _+ 5 s. Again draw off the lower H2SO, layer into the 50-mL volumetric 9 Thiophene such as Eastman Catalog No. 1860 or equivalent has been found satisfactory for this purpose.

I I. Procedure 11.1 To a 500-mL separatory funnel, add 250 mL of sample and 40 mL of cadmium chloride solution. Stopper and shake for approximately 30 s. Allow to settle and discard the aqueous layer. Filter the benzene layer through medium filter paper into a 250-mL graduated cylinder. Part of the filtered benzene is to be used for the sample blank. Proceed with preparation of the sample blank as described in 9.3. From the remaining filtered benzene, transfer 100 mL to 250-mL separatory funnel. 11.2 To the separatory funnel add 5 mL of isatin solution and 10 mL of ferric sulfate-sulfuric acid solution. Stopper and shake for 2 rain _+ 15 s. Allow the phases to separate and draw off the lower H2SO4 layer into a 50-mL volumetric flask. Add 10 mL of H2SO4 to the separatory funnel, stopper, and shake for 30 _+ 5 s. Again draw offthe lower H2SO, layer into the 50-mL volumetric flask containing the first extract. Dilute to volume with H2SO4 and mix. 11.3 Measure the absorbance of this material at 589 nm in a l-cm cell versus Reagent Blank 1 (9.1) in a matched I-cm 278

o 16as TABLE 1 Designation of Equation of Section 11 A B

Calculation Factors

Cell Solutions Solution of Sample

Versus

H2SO4. Fe2(SO4)3; isatin after contact with sample, (see 11.2) sample blank (see 9.3)

cell. Instrument conditions should be identical with those employed during calibration. 11.4 Determine the concentration of thiophene from the calibration curve (Section 10). If the absorbance is greater than 1.5, repeat the procedure using a 50-mL specimen instead of 100 mL. If the 50-mL specimen still gives absorbance above 1.5, then the specimen must be diluted with thiophene-free benzene before proceeding. 11.5 Determine the absorbance of the sample blank (9.3) at 589 nm using Reagent Blank 2 (9.2) as reference. Determine the apparent concentration of thiophene in the sample blank.

Solution of Reference reagent blank 1 (see 9.1) reagent blank 2 (see 9.2)

TABLE 2

Precision Limits

Thiophene Concentration, Range, mg/kg

Repeatability, Percent of Value

Reproduobility, Percent of Value

100 to 250 20 to 100 2 to 20 0.4 to 2 less than 0.4

11.4 12.3 13.8 14.0 less than 0.06 mg/kg

15 19 21 25 less than 0.15 mg/kg

13. Precision and Bias 13.1 The data given in Table 2 should be used for judging the acceptability of results (95 % probability). NOTE 2--The precision limits given in Table 2 are based on data published as Appendix III to Report of Committee D-16, ASTM Proceedings, Am. Soc. Testing Mats., Vol 59, 1959, p. 514.

12. Calculation 12.1 Calculate the thiophene content of the sample in milligrams per kilogram as follows:

13.2 Repeatability is based on test results obtained by repetitive testing of a homogeneous sample by a single operator. Reproducibility is based on test results obtained by repetitive testing of different samples in different laboratories and different operators. 13.3 Bias--The bias of this test method has not been determined.

Thiophene, mg/kg = ( A - B ) F / d

where: A = thiophene for sample determined from appropriate calibration curve (see Table 1), ~tg/mL, B = apparent thiophene determined for sample blank from appropriate calibration curve (see Table 1), ~tg/mL, F = dilution factor of sample, and d = density of benzene at the temperature of the sample.

14. Keywords 14.1 benzene; spectrophotometry; thiophene

The American Society for Testing and Materials takes no position respecting the vahdity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the vahdity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and ff not revised, either reepproved or withdrawn. Your comments are mvited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will recewe careful consideration at a meeting of the responsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103.

279

) Designation: D 1747 - 94

An American National Standard

Standard Test Method for Refractive Index of Viscous Materials 1 This standard is issued under the fixed designation D 1747; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (~) indicates an editorial change since the last revision or reapproval.

This test method has been approvedfor use by agencies of the Department of Defense. Consult the DoD Index of Specifications and Standards for the specific year of issue which has been adopted by the Department of Defense.

3.1.1 refractive index--the ratio of the velocity of light (of specified wavelength) in air, to its velocity in the substance under examination. The relative index of refraction is defined as the sine of the angle of incidence divided by the sine of the angle of refraction, as light passes from air into the substance. If absolute refractive index (that is, referred to vacuum) is desired, this value should be multiplied by the factor 1.00027, the absolute refractive index of air. The numerical value of refractive index of liquids varies inversely with both wavelength and temperature.

1. Scope 1.1 This test method covers the measurement of refractive indexes, accurate to two units in the fourth decimal place, of transparent and light-colored viscous hydrocarbon liquids and melted solids which have refractive indexes in the range between 1.33 and 1.60, and at temperatures from 80 to 100*C. Temperatures lower than 80"C can be used provided that the melting point of the sample is at least 10*C below the test temperature. 1.2 This test method is not applicable, within the accuracy stated, to liquids having colors darker than ASTM Color No. 4 ASTM color as determined by Test Method D 1500, to liquids which smoke or vaporize readily at the test temperature, or to solids melting within 10*C of the test temperature. NOTE l - - T h e

i n s t r u m e n t can be successfully used for refractive

indices above 1.60;but since certifiedliquid standardsfor ranges above 1.60 are not yet available, the accuracy of measurement under these conditionshas not been evaluated. 1.3 The values stated in SI units are to be regarded as standard. The values stated in inch-pound units are for information only. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazards, see Notes 4, 5, and 6.

2. Referenced Documents 2. I A S T M Standards: D 362 Specification for Industrial Grade Toluene2 D 841 Specification for Nitration Grade Toluene 3 D 1218 Test Method for Refractive Index and Refractive Dispersion of Hydrocarbon Liquids4 D 1500 Test Method for ASTM Color of Petroleum Products (ASTM Color Scale)4 E 1 Specification for ASTM Thermometers5 3. Terminology 3.1 Definition:

4. Summary of Test Method 4.1 The refractive index normally is measured by the critical angle method using monochromatic light from a sodium lamp. The instrument is previously adjusted by means of calibration obtained with certified liquid standards.

5. Significance and Use 5.1 Refractive index is a fundamental physical property that can be used in conjunction with other properties to characterize pure hydrocarbons and their mixtures. 5.2 The use of refractive index in correlative methods for the determination of the gross composition of viscous oils and waxes often requires its measurement at elevated temperatures. 6. Apparatus 6.1 Refractometer, precision Abb~-type,6 having a range in refractive index from 1.30 to 1.63. The prism assembly shall be insulated with cork as necessary to minimize temperature fluctuations during measurement of the refractive index. 6.2 Thermostat and Circulating Pump, capable of maintaining the indicated prism temperature constant within 0.02"C. The circulating fluid consists of ethylene glycol or a mixture of 30 to 40 volume % of glycerin in water flowing through the prisms at a fixed rate of at least 2.5 L/min. For work at 100*C, properly controlled wet steam is also suitable. NOTE 2 - - T h e constancy o f the prism temperature can be seriously

affectedby variationsin ambientconditionssuchas air draftsor changes in room temperature. Reasonable precautions should be taken to minimizethese factors.Insulationplaced on the thermostat,circulating fluid lines, and refractometeralso may prove to be helpful. 6.3 Thermometers, conforming to Thermometer 21C for

t This test method is under the jurisdiction of ASTM Committee I)-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.04.0D on Physical Methods. Current edition approved July 15, 1994. Published September 1994. Originally published as D 1747 - 60 T. Last previous edition D 1747 - 89. 2 Discontinued--See 1988 Annual Book of ASTM Standards, Vol 06.03. 3 Annual Book of ASTM Standards, Vol 06.04. 4 Annual Book of ASTM Standards, Vol 05.0 I. 5 Annual Book of ASTM Standards, Vol 14.03.

6 The Abl~-type precision refractometer is no longer available but may be obtainable from instrument exchanges or used equipment suppliers. Other precision refractometers may be suitable, but they have not as yet been tested cooperatively.

280

(~) D 1747 TABLE 1

shall be free of suspended solids, water, or other materials that tend to scatter light. Water can be removed from hydrocarbons by treatment with calcium chloride followed by filtering or centrifuging to remove the desiccant. The possibility of changing the composition of a sample by action of the drying agent, by selective adsorption on the filter, or by fractional evaporation, shall be considered.

Primary Liquid Standards

Certified Standard

Approximate Refractive

n-Hexadecane trans -Decahydronapht halene 1-Methylnaphthalene

1.41 1.44 1,59

Index, n D

determinations at 80C or Thermometer 22C for determinations at 100C as given in Specification E l are recommended. The thermometer, suitably calibrated, shall be located in the outlet stream from the measuring prism within an appropriate holder as described in Test Method D 1218. The holder shall provide for adequate immersion of the thermometer and for free flow of the circulating fluid. The thermometer-holder assembly shall be insulated with cork or other suitable material to minimize temperature fluctuations. 6.4 Thermocouple, 7 copper-constantan foil type, 0.0005 in. (0.013 mm) thickness, and precision potentiometer. The thermocouple is calibrated by immersing to a depth of 1 in. (25 mm) in a circulating liquid thermostat and comparing with a thermometer of known accuracy. 6.5 Light Source, Sodium Arc Lamp--The light source shall be a sodium arc lamp, which shall be used only after the removal of Amici compensating prisms, if there are any present in the instrument. NoTE 3--If the field division as observed in 12.2 shifts when the Amici prism is rotated, the prism should be removedto avoid incorrect readings. 7. Solvents 7.1 Trichloroethane, a good solvent for hydrocarbons, polymers, and olefinic gums. NOTE 4: Warning--Harmful if inhaled. High concentration can cause unconsciousnessor death. Contact can cause skin irritation and dermatitis. 7.2 Toluene, conforming to Specification D 362 or Specification D 841. NOTE 5: Warning--Flammable.Vapor harmful.

10. Preparation of Apparatus 10.1 The refractometer shall be kept scrupulously clean at all times. Dust and oil, if allowed to accumulate on any part of the instrument, will find its way into the moving parts, causing wear and eventual misalignment. If permitted to collect on the prism, dust will dull the polish, resulting in hazy lines. 10.2 Thoroughly clean the prism faces with fresh clean lens tissue or surgical grade absorbent cotton saturated with a suitable solvent. Pass the swab very lightly over the surface until it shows no tendency to streak. Repeat the procedure with a fresh swab and solvent until both the glass and adjacent polished metal surfaces are clean. Do not dry the prism faces by rubbing with dry cotton. 10.3 Adjust the thermostat so that the temperature as indicated by the thermocouple inserted between the prism faces and wet with oil is within 0.2"C of the desired test temperature. This temperature is to be held constant to within 0.020C during the test. Observe and record the thermometer reading corresponding to the test temperature. Turn on the sodium arc lamp and allow it to warm up 30 min. 11. Standardization with Reference Liquids 11.1 Introduce a sample of the API Standard transdecahydronaphthalene to the prism which is adjusted to the chosen test temperature of 80 or 100*C, turn the telescope adjustment screw until a refractive index scale reading corresponding to the certified refractive index for trans. decahydronaphthalene is observed, and adjust the instrument according to the instructions given by the manufacturer until the sharp boundary between the light and dark portions of the field passes through the intersection of the cross hairs of the telescope. 11.2 Check the accuracy of this setting by loading a fresh sample of trans-decahydronaphthalene and measure its refractive index at the test temperature following the procedure described in Section 12. If the value for the refractive index differs from the certified value by 0.0001 or more units, then repeat the procedure given in 11.1 until a satisfactory check is obtained. 11.3 Measure the refractive index of API Standard nhexadecane and 1-methylnaphthalene at the test temperature following the procedure described in Section 12. 11.4 Construct a calibration curve for use at the chosen test temperature. Plot the difference between the observed refractive index for n-hexadecane and its certified value along the ordinate against the refractive index level along the abscissa. Also plot the difference between the observed and certified refractive indices for l-methylnaphthalene in the same manner. Draw a straight line from the point representing the deviation found for n-hexadecane to zero at the certified refractive index of trans-decahydronaphthalene.

8. Reference Standards

8. l Primary Liquid StandardsmThe organic liquids listed in Table l, with the values of their refractive indexes for the sodium D line certified at 20, 25, 30, 80, and 100*C can be obtained from API Standard Reference Office, CarnegieMellon University, Pittsburgh, PA 15213. 8.2 Working Standards--For working standard hydrocarbons, reasonably well purified samples of n-hexadecane, trans-decahydronaphthalene, and l-methylnaphthalene may be used. Their exact values are determined by comparison with standard samples of the same hydrocarbons having certified values of refractive index. NOTE 6: C a u t i o n - - B o t h primary and working standards are c o m bustible.

9. Sample 9.1 A sample of at least 0.5 mL is required. The sample 7 A suitable thermocouple is available from RdF Corp., 23 Elm Avenue, Hudson, NH 03051. Part number 20014 should be specified.

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~

D 1747 stirring rod, being careful not to touch the prism surface with the rod. If not enough sample has been used to fill the space between the prisms completely or evaporation causes the field division in the telescope to become uneven, clean the prisms thoroughly before employing a new portion of the sample. 12.3 Set the light source to pass rays into the illuminating prism. Move the telescope by means of the adjustment screw until the field division is visible in the telescope. 12.4 Adjust the angle of incidence until the field consists of a light and a dark portion separated by a sharp boundary which may be brought into focus by sliding the telescope eyepiece. In the case of colloidal or suspended matter in the sample, the boundary line may appear diffused or hazy, even though the telescope is perfectly focused. Filtration of the sample will sometimes correct this condition. Water in the sample may also give this hazy effect. 12.5 Turn the adjustment screw so that the field division passes through the intersection of the crossed lines in the telescope. With the exception of extremely volatile samples, an interval of 2 to 3 min should be allowed before taking readings to permit the sample to come to the same temperature as the refractometer. In setting the edge of the field on the cross hairs, at least two determinations should be obtained which agree within 0.00005 to 0.0001 for precision work. The final reading is best obtained by approaching this setting successively from both light and dark sides of the field. Read the scale through the microscope provided. Focus by sliding the eyepiece in or out. Measure and record the refractive index using at least two separate loadings of sample. NOTE 7--For more reliable results with a sample which shows a diffused or hazy boundary line even after filtration, there are two possible remedies: (1) back window reflection if the refractometer is so equipped, or (2) dilution with a suitable solvent. (1) Back window reflection also permits measurements of samples too dark for normal operation. The sample is charged in the normal manner. Remove the cover plate on the back of the prism housing and position the light source so that it shines directly into the opening. Bring the boundary line into view. The fieldswill be reversedand considerably reduced in contrast. Read the refractive index as described above. Care should be exercised during the measurement since the sharp boundary line is faint and difficult to distinguish. (2) The dilution procedure is generally unsatisfactory and should only be used if it is impossible to obtain consistent readings in any other way. The sample is diluted with an equal volume of high boiling solvent whose density and refractive index are known and an appropriate correction applied to the results. Highly aromatic or olefinic samples in the gas oil range can be measured by this procedure. The possibility of volume change on mixing should be considered. A check on the density of the mixture will show if this occurs.

Likewise, draw a straight line from this same zero point to the deviation found for l-methylnaphthalene. 11.5 If it is desired to measure the refractive index of samples at a temperature other than 80 or 100*C, obtain calibration data by repeating l l.1 to l l.4 at this desired temperature. Determine the refractive indices for the API Standard compounds, n-hexadecane, trans-decahydronaphthalene, and 1-methylnaphthalene at the desired temperature by plotting the certified refractive indices at 20, 25, 30, 80, 100*C against temperature and drawing a smooth curve between the points. I 1.6 Precautions--In using pure liquids for calibration or checking of calibration of an Abb~-type refractometer, the following precautions should be observed: l l.6.1 Before inserting the hydrocarbon calibrating liquids, the prisms should be flushed with solvents and cleaned as described in 8.2. It is advisable to preheat the solvent before use to minimize thermal shock to the prism. This should be followed by several such flushings with the test liquid and wiping with lens paper. After such cleaning a reading with the test liquid should be taken as described in Section I I. This should be followed by another flushing with the test liquid before taking another reading of the test liquid in the prescribed manner. The prisms cannot be considered free from contaminating substances until two such determinations on the test liquid agree within the limits given in I 1.6.2. 11.6.2 In setting the edge of the field on the cross hairs, readings should be taken in pairs, approaching the alidade setting from one direction only as recommended by the manufacturer. Several such sets will probably be necessary before satisfactory agreement is obtained. Satisfactory agreement is 0.00005 to 0.0001. I 1.6.3 For results of highest accuracy, the calibration with hydrocarbons of known properties should be made immediately before the determination on the sample. 11.6.4 Fluctuations in ambient temperatures should be minimized as much as possible during the test. 12. Procedure 12.1 Thoroughly clean the prism faces as described in 10.2. Adjust the thermostat so that the temperature indicated by the thermocouple placed between the faces of the closed prism (loaded with oil) is within 0.2"C of the desired value. The thermocouple is used for establishing the correct temperature level and may be removed during measurements of refractive index. The observed reading of the thermometer at this temperature must be held constant to 0.02"C in the measurements to follow. 12.2 Close the prism box and let it stand for 3 to 5 min to ensure temperature equilibrium between the prisms and the circulating bath liquid. Melt samples which are normally solid in a small container and charge as a liquid to the prism. Charge the sample from a small pipet or medicine dropper through the refractometer opening or onto the prisms open just enough to admit the sample. About 0.2 to 0.5 m L of the sample should be allowed to flush through before completely closing the prisms. Samples of low volatility or high viscosity may be placed directly onto the prism surface by means of a

13. Calculation and Reporting 13.1 Correct the observed refractive index by the amount shown in the calibration curve. Report the value of refractive index as: lid

t

..~

. • .

14. Precision and Bias 14.1 The precision of the test method as obtained by statistical examination of interlaboratory test results is as follows:

282

(~ D 1747 14.1.1 Repeatability--The difference between successive test results obtained by the same operator with the same apparatus under constant operating conditions on identical test material, would in the long run, in the normal and correct operation of the test method, exceed 0.00007 units of refractive index only in one case in twenty. 14.1.2 ReproducibilitymThe difference between two single and independent results, obtained by different operators working in different laboratories on identical test material, would in the long run, in the normal and correct operation of the test method, exceed 0.0006 units of refractive index only in one case in twenty.

NOTE 8--The precision for this test method was not obtained in accordance with RR:D02-1007.8 14.2 The bias for this test method has not been determined. Subcommittee D02.04.0D plans to cooperatively test modern refractometers and determine the bias.

15. Keywords 15.1 oils; purity; refractive index; reffactometer; wax 8 Annual Book of ASTM Standards, Vol 05.03.

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the vafidity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend, if you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103.

283

~ l l ~ Designation:D 1840 - 96

An American NatlonaJStandard

Standard Test Method for Naphthalene Hydrocarbons in Aviation Turbine Fuels by Ultraviolet Spectrophotometry 1 This standard is issued under the fixed designation D 1840; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last re,approval. A superscript epsilon (t) indicates an editorial change since the last revision or reapproval.

This test method has been adopted for use by government agencies to replace Method 3704 of Federal Test Method Standard No. 791b.

T = P/Po

1. Scope 1.1 This test method covers the determination, by ultraviolet spectrophotometry, of the total concentration of naphthalene, acenaphthene, and alkylated derivatives of these hydrocarbons in straight-run jet fuels containing not more than 5 % of such components and having end points below 315"C (600*F). This test method determines the maximum amount of naphthalenes that could be present. 1.2 The values stated in SI units are to be regarded as the standard. The values stated in inch-pound units are for information only. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific precautionary statements see 8.1 and 8.2.

(1)

where: P = radiant power passing through the sample, and Po = radiant power incident upon the sample. 3.2.2 absorbance, A, n - - t h e molecular property of a substance that determines its ability to take up radiant power, expressed by A = lOglo (l/T) -- -logtoT

(2)

where: T = transmittance as defined in 3.2.1. 3.2.2.1 Discussion--It may be necessary to correct the observed transmittance (indicated by the spectrophotometer) by compensating for reflectance losses, solvent absorption losses, or refraction effects. 3.2.3 absorptivity, a, n - - t h e specific property of a substance to absorb radiant power per unit sample concentration and pathlength, expressed by

2. Referenced Documents

a = A/bc

2.1 A S T M Standards: E 131 Terminology Relating to Molecular Spectroscopy2 E 169 Practices for General Techniques of UltravioletVisible Quantitative Analysis 2 E 275 Practice for Describing and Measuring Performance of Ultraviolet, Visible, and Near Infrared Spectrophotometers 2

(3)

where: A = absorbance defined in 3.2.2, b = sample cell path length, and c --quantity of absorbing substance contained in a unit volume of solvent. 3.2.3.1 Discussion--Quantitative ultraviolet analyses are based upon the absorption law, known as Beer's law. The law states that the absorbance of a homogeneous sample conraining an absorbing substance is directly proportional to the concentration of the absorbing substance at a single wavelength, expressed by

3. Terminology

3.1 Definitions: 3.1.1 Definitions of terms and symbols relating to absorption spectroscopy in this test method shall conform to Terminology E 131. Terms of particular significance are the following: 3.1.1.1 radiant energy, nmenergy transmitted as electromagnetic waves. 3.1.1.2 radiant power, P, n - - t h e rate at which energy is transported in a beam of radiant energy. 3.2 Definitions of Terms Specific to This Standard." 3.2.1 transmittance, T, n - - t h e molecular property of a substance that determines its transportability of radiant power expressed by

A = abe

(4)

where: A = absorbance as defined in 3.2.2, a = absorptivity as defined in 3.2.3, b = sample cell pathlength, and c = quantity of absorbing substance contained in a unit volume of solvent. 3.2.4 sample cell pathlength, b, n - - t h e distance, in centimetres, measured in the direction of propagation of the beam of radiant energy, between the surfaces of the specimen on which the radiant energy is incident and the surface of the specimen from which it is emergent. 3.2.4.1 Discussion--This distance does not include the thickness of the cell in which the specimen is contained. 3.2.5 concentration, c, n m t h e quantity of naphthalene hydrocarbons in grams per litre of isooctane.

t This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.04 on Hydrocarbon Analysis. Current edition approved Apr. 10, 1996. Published June 1996. Originally published as D 1840 - 61 T. Last previous edition D 1840 - 92. 2 Annual Book of ASTM Standards, Vol 03.06.

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~

O 1840 NOTE 2: Warning--lsooctane is extremely flammable, harmful if inhaled. NOTE 3--Spectroscopic-grade isooctane is available commercially. Technical-grade isooctaneis a satisfactory base stock for the preparation of spectroscopic solvent. Allow about 4 or 5 L of this material to percolate through a column of activated silica gel (74 lam) 50.8 to 76.2 mm in diameter and 0.6 to 0.9 m in depth. Collect only the portion of the solvent that has a transmission compared to distilled water greater than 90 % over the entire spectral range from 240 to 300 nm. Store in scrupulously clean glass-stoppered bottles and always keep covered. In general it will be best to use a fresh portion of silica gel in preparing a new batch of solvent. However the gel can be reactivated by pouring 500 mL of acetone through the column, draining, drying by suction, and heating the gel in thin layers in an oven at 400"C until white color is restored. Activated silica gel is stored in closed containers.

4. Summary of Test Method 4.1 The total concentration of naphthalenes in jet fuels is determined by measurement of the absorbance at 285 nm of a solution of the fuel at known concentration. 5. Significance and Use 5.1 This test method for naphthalene hydrocarbons is one of a group of tests used to assess the combustion characteristics of aviation turbine fuels of the kerosene boiling range. The naphthalene hydrocarbon content is determined because naphthalenes, when burned, tend to have a relatively larger contribution to a sooty flame, smoke, and thermal radiation than single ring aromatics.

8.2 Solvents for Cleaning Cells--Residue.free acetone or

6. Interferences 6.1 Interferences add to the apparent naphthalene content. Phenanthrenes, dibenzothiophenes, biphenyls, benzothiophenes, and anthracenes interfere if present. The end point limitation of 315"C will minimize this interference except for benzothiophenes and biphenyls. The contribution to measured naphthalene content by the presence of 1% of such interfering compounds can be estimated from Table 1. 6.2 Saturated hydrocarbons, oleflns, thiophenes, and alkyl or cycloalkyl derivatives of benzene will not interfere.

ethyl alcohol. NOTE 4: Warning--Acetone and ethyl alcohol are extremely flammable and can be harmful if inhaled.

9. Calibration and Standardization 9.1 Instead of direct calibration of the spectrophotometer with known naphthalenes, the average absorptivity of the C~o to C~3 naphthalenes at 285 nm can be taken at 33.7 L/g.cm. The data used to calculate this average are given in Section 10.

7. Apparatus

7.1 Spectrophotometer, equipped to measure the absorbance of solutions in the spectral region 240 to 300 nm with a spectral slit width of I nm or less. Wavelength measurements shall be repeatable and known to be accurate within 0.1 nm or less as measured by mercury emission line at 253.65 nm or the absorption spectrum of either holmium oxide glass at 287.5 nm or holmium oxide solution at 287.1 nm. At the 0.4 absorbance level in the spectral region between 240 and 300 nm, absorbance measurements shall be repeatable within +0.5 % or better. In the absorbance range encompassing 0.2 to 0.8, the photometric accuracy shall not differ by more than +0.5 % of samples whose absorbance has been established by a standardizing laboratory. 7.2 It shall be initially and thereafter periodically demonstrated that an instrument can be operated in a manner to give test results equivalent to those described in 7.1.

10. Procedure 10.1 For recommended techniques, refer to Practices E 169. Check carefully sections on handling and cleaning of cells and glassware, instrument adjustments, and method of absorbance measurement. 10.2 Prepare three dilutions of the sample as follows: 10.2.1 First Dilution--Add 10 to 15 m L of spectroscopic isooctane to a clean, dry, glass-stoppered, 25-mL volumetric flask. Weigh out approximately 1 g of sample in the flask, dilute to volume with spectroscopic solvent, and mix thoroughly. 10.2.2 Second DilutionmPipet 5.00 m L of the first dilution into a 50-mL glass-stoppered volumetric flask, dilute to volume with spectroscopic isooctane, and mix thoroughly. 10.2.3 ThirdDilution--Dilute 5.00 m L of second dilution to 50 m L in the same manner as in 10.2.2. 10.3 Measurement of Absorbance--Pipet portions of the third dilution into the sample cell of the spectrophotometer. Cover the cells immediately to prevent transfer of aromatic hydrocarbons from the sample cell to the solvent cell. Check the windows of the absorption cells and make certain they are clean. Measure the absorbance as recommended in Practices E 169. Record the absorbance of the sample as compared to spectroscopic isooctance at 285 nm,

NOTE l--For recommended methods of testing spectrophotometers

to be used in this test method refer to Practice E 275. 7.3 Vitreous Silica Cells, two, having path lengths of 1.00 _+ 0.005 cm. 7.4 Pipets, calibrated with isooctane for volume delivery. 7.5 Lens Paper.

8. Solvents

8.1 Spectroscopic 2,2,4 Trimethyl Pentane (Isooctane)

NOTE 5--The dilution of the sample should be controlled so that absorbance readings fall within a range of 0.2 to 0.8 for maximum reproducibifity of results. To accomplish this it may be necessary to use an alternative third dilution such as 10 mL of the second dilution to 25 mL with solvent.

TABLE 1 Type of Interfering Compound Phenanthrenes Dibenzothlophenes Biphenyls Benzothiophenes Anthracenes

Error in Percentage of Naphthalenes Caused by 1% Interfering Compound 2 2 1

10.4 Determination of Cell Correction--Measure and record the absorbance of the spectroscopic isooctance-filled sample cell as compared to the spectroscopic isooctancefilled solvent cell.

0.6

0.1

285

(@) D 1840 TABLE 2

Data Issued by API Research Project 44 API Sedal Compound Number L/g- cm

11. Calculations 11.1 Calculate the mass percentage of naphthalenes in the sample as follows: Naphthalenes, mass % = (AK/33.7IV) x 100

Naphthalene 1-methyl Naphthalene 2-methyl Naphthalene 1,2-dlmethyl Naphthalene 1,3-dimethyl Naphthalene 1,4-dimethyl Naphthalene 1,5-dimethyl Naphthalene 1,6-dlmethyl Naphthalene 1,7-dimethyl Naphthalene 1,8-dlmethyl Naphthalene 2,3-dimethyl Naphthalene 2,6-dimethyl Naphthalene 2,7-dimethyl Naphthalene 14sopropyl Naphthalene

(5)

where: A = corrected absorbance (observed absorbance minus cell correction) of the dilution measured, K = equivalent volume of solvent, in liters, if the dilution had been made in a single step. For the first dilution K = 0.025, for the second dilution K = 0.25, for the third dilution K = 2.5. For the suggested alternative third dilution K = 0.625, W = grams of sample used, and 33.7 = the average absorptivity of C~o to CI3 naphthalenes in litres per gram-centimeter. 11.2 Calculate the volume percentage of naphthalenes as follows: Naphthalenes, volume % = M x (B/C)

605 539 572 215 216 217 218 219 220 221 222 226 224 203

28.5 32.0 22.9 37.3 36.4 43.5 54.0 36.4 36.0 46.0 22.0 21.3 23.5 31.7

14.1.1 RepeatabilitymThe difference between successive test results obtained by the same operator with the same apparatus under constant operating conditions on identical test materials would, in the long run, in the normal and correct operation of the test method exceed the following values only in one case in twenty.

(6)

where: M = percentage of naphthalenes by mass, B = relative density of the total fuel (15"C/15"C), and C = relative density of the naphthalenes (15"C/15"C) =

Repeatability -- 0.0222 (1.00 + X) where: X = average of two results, volume %. 14.1.2 Reproducibility--The difference between two single and independent results obtained by different operators working in different laboratories on identical test material would, in the long run, in the normal and correct operation of the test method exceed the following values only in one case in twenty. Reproducibility = 0.0299 (1.00 + X)

1.00. 12. Report 12. I Numerical values of volume percent naphthalene are reported to the nearest 0.01%. 13. Reference Spectra 13.1 Absorptivities of individual naphthalene hydrocarbons at 285 nm are derived from data in the API catalog of ultraviolet spectral data issued by Research Project 44 as given in Table 2. NOTe 6--The arithmetic average of the above absorptivities is 33.7. The reliability of the average absorptivity as a measure of selected individual naphthalenes can be estimated from the above table. 14. Precision and Bias 14.1 Precision3NThe precision of this test method as determined by the statistical examination of interlaboratory test results is as follows:

where: X -- average of two results, volume %. NOTS 7--1nstruments not conforming to the equipment specificationsin 7.I can resultin much poorer precision. 14.2 BiasmBias cannot be determined for the procedure in this test method for measuring naphthalene hydrocarbon because the absorptivity will vary with composition of the individual naphthalene derivatives in samples. 15. Keywords 15.1 aviation turbine fuels; naphthalene hydrocarbons; ultraviolet spectrophotometry

3 Supporting data arc available from ASTM Headquartcn as a research report. Request RR:D02-1375.

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned In this standard. Users of this standard are expresaly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and ff not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend, ff you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 100 Barr Harbor Drive, West Conshohockan, PA 19428.

286

(~

Designation:D 1945 - 96 Standard Test Method for Analysis of Natural Gas by Gas Chromatography 1 This standard is issued under the feted designation D 1945; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (0 indicates an editorial change since the last revision or veapproval.

1. Scope 1.1 This test method covers the determination of the chemical composition of natural gases and similar gaseous mixtures within the range of composition shown in Table 1. This test method may be abbreviated for the analysis of lean natural gases containing negligible amounts of hexanes and higher hydrocarbons, or for the determination of one or more components, as required. 1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

for calculating physical properties of the sample, such as heating value and relative density, or for monitoring the concentrations of one or more of the components in a mixture.

2. Referenced Documents 2.1 A S T M Standards: D 2597 Test Method for Analysis of Demethanized Hydrocarbon Liquid Mixtures Containing Nitrogen and Carbon Dioxide by Gas Chromatography2 D 3588 Practice for Calculating Heat Value, Compressibility Factor, and Relative Density (Specific Gravity) of Gaseous Fuels3 E 260 Practice for Packed Column Gas Chromatography 4 3. Summary of Test Method 3.1 Components in a representative sample are physically separated by gas chromatography (GC) and compared to calibration data obtained under identical operating conditions from a reference standard mixture of known composition. The numerous heavy-end components of a sample can be grouped into irregular peaks by reversing the direction of the carder gas through the column at such time as to group the heavy ends either as C5 and heavier, C6 and heavier, or C7 and heavier. The composition of the sample is calculated by comparing either the peak heights, or the peak areas, or both, with the corresponding values obtained with the reference standard. 4. Significance and Use 4.1 This test method is of significance for providing data ' This test method is under the jurisdiction of ASTM Committee D-3 on Gaseous Fuels and is the direct responsibility of Subcommittee D 03.07 on Analysis of Chemical Composition of Gaseous Fuels. Current edition approved Nov. 10, 1996. Published January 1997. Originally published as D 1945 - 62 T. Last previous edition D 1945 - 91. 2 Annual Book of ASTM Standards, Vol 05.02. 3 Annual Book of ASTM Standards, Vol 05.05. 4 Annual Book of ASTM Standards, Voi 14.02.

287

5. Apparatus 5.1 Detector--The detector shall be a thermal-conductivity type, or its equivalent in sensitivity and stability. The thermal conductivity detector must be sufficiently sensitive to produce a signal of at least 0.5 mV for l tool % n-butane in a 0.25-mL sample. 5.2 Recording Instruments--Either strip-chart recorders or electronic integrators, or both, are used to display the separated components. Although a strip-chart recorder is not required when using electronic integration, it is highly desirable for evaluation of instrument performance. 5.2.1 The recorder shall be a strip-chart recorder with a full-range scale of 5 mV or less (1 mV preferred). The width of the chart shall be not less than 150 ram. A maximum pen response time of 2 s (1 s preferred) and a minimum chart speed of 10 mm/min shall be required. Faster speeds up to 100 ram/rain are desirable if the chromatogram is to be interpreted using manual methods to obtain areas. 5.2.2 Electronic or Computing Integrators--Proof of separation and response equivalent to that for a recorder is required for displays other than by chart recorder. Baseline tracking with tangent skim peak detection is recommended. 5.3 Attenuator--If the ehromatogram is to be interpreted using manual methods, an attenuator must be used with the detector output signal to maintain maximum peaks within the recorder chart range. The attenuator must be accurate to within 0.5 % between the attenuator range steps. 5.4 Sample Inlet System: 5.4.1 The sample inlet system shall be constructed of materials that are inert and nonadsorptive with respect to the components in the sample. The preferred material of construetion is stainless steel. Copper, brass, and other copperbearing alloys are unacceptable. The sample inlet system from the cylinder valve to the GC column inlet must be maintained at a temperature constant to _+l*C. 5.4.2 Provision must be made to introduce into the carrier gas ahead of the analyzing column a gas-phase sample that has been entrapped in a fixed volume loop or tubular section. The fixed loop or section shall be so constructed that the total volume, including dead space, shall not normally exceed 0.5 mL at latm. If increased accuracy of the hexanes and heavier portions of the analysis is required, a larger sample size may be used (see Test Method D 2597). The sample volume must be reproducible such that successive runs agree within 1% on each component. A flowing sample inlet system is acceptable as long as viscosity effects are

~) TABLE 1

D 1945

Natural Gas Components and Range of Composition Covered

Component

constant to 1% throughout the analysis of the sample and the reference standard. The purity of the carrier gas may be improved by flowing the carrier gas through selective filters prior to its entry into the chromatograph. 5.8 Columns: 5.8.1 The columns shallbe constructed of materialsthat are inertand nonadsorptive with respectto the components in the sample. The preferred material of construction is stainlesssteel.Copper and copper-bearing alloysare unacceptable. 5.8.2 An adsorption-type column and a partition-type column may be used to make the analysis.

Mol

Helium Hydrogen Oxygen Nitrogen Carbondioxide Methane Ethane Hydrogen sulfide Propane Isobotene n-Butane neoPentane IsoPentano n-Pentane Hexane isomers Heptanes plus

0.01 to 10 0.01 to 10 0.01 to 20 0.01 to 100 0.01 to 20 0.01 to 100 0.01 to 100 0.3 to 30 0.01 to 100 0.01 to 10 0.01 to 10 0.01 to 2 0.01 to 2 0.01 to 2 0.01 to 2 0.01 to 1

NOTE 2 - - ~ Practic~ E 260.

accounted for. N o ~ I - - T h e sample size limitation of 0.5 mL or smaller is selected relative to lineauity of detector response, and efficiency of column separation. Larger samples may be used to determine low-quantity components in order to increase measurement accuracy.

5.4.3 An optional manifold arrangement for entering vacuum samples is shown in Fig. 1. 5.5 Column Temperature Control." 5.5.1 Isothermal--When isothermal operation is utilized, maintain the analyzer columns at a temperature constant to 0.3"C during the course of the sample run and corresponding reference run. 5.5.2 Temperature ProgrammingmTemperature programming may be used, as feasible. The oven temperature shall not exceed the recommended temperature limit for the materials in the column. 5.6 Detector Temperature Control--Maintain the detector temperature at a temperature constant to 0.3"C during the course of the sample run and the corresponding reference run. The detector temperature shall be equal to or greater than the maximum column temperature. 5.7 Carrier Gas ControlsDThe instrument shall be equipped with suitable facilities to provide a flow of carder gas through the analyzer and detector at a flow rate that is

5.8.2.1 Adsorption Column--This column must completely separate oxygen, nitrogen, and methane. A 13X molecular sieve 80/100 mesh is recommended for direct injection. A 5A column can be used if a pre-cut column is present to remove interfering hydrocarbons. If a recorder is used, the recorder pen must return to the baseline between each successive peak. The resolution (R) must be 1.5 or greater as calculated in the following equation: x2 - xl R(l,2)= × 2, (I) Y2 + Y~

where xl, x2 are the retention times and yl, Y2 are the peak widths. Figure 2 illustrates the calculation for resolution. Figure 3 is a chromatogram obtained with an adsorption column. 5.8.2.2 Partition Column--This column must separate ethane through pentancs, and carbon dioxide. Ifa recorder is used, the recorder pen must return to the base line between each peak for propane and succeeding peaks, and to base line within 2 % of full-scale deflection for components cluted ahead of propane, with measurements being at the attenuation of the peak. Separation of carbon dioxide must be sufficient so that a 0.25-mL sample containing 0. l-mol % carbon dioxide will produce a clearly measurable response. The resolution (R) must be 1.5 or greater as calculated in the above equation. The separation should be completed within 40 min, including reversal of flow alter n-pentane to yield a group response for hexanes and header components. Figures

TO VACUUM NEEDLE ~

l

P

U

M

TO

MERCURY TRAP

P

CARRIER ~'--~-J_ TO GAS 1 COLUMN VEW£ GAS CHROMATOGRAPH SAMPLE VALVE SAMPLE MANOMETER CYLINDER

FIG. 1

SuggestedManifoldArrangementfor EnteringVacuumSemples 288

~ D 1945 x2 v

XI

,,.J:

Z (.o (/3

l O RETENTION FIG. 2

Calculation for Resolution

4, 5, and 6 are examples of chromatograms obtained on some of the suitable partition columns. 5.8.3 General--Other column packing materials that provide satisfactory separation of components of interest may be utilized (sec Fig. 7). In multi-column applications, it is preferred to use front-end backflush of the heavy ends.

moisture without removing selective components to be determined in the analysis. NOTE 4--SeeAnnex A2.2 forpreparationofa suitabledrier. 5.10 Valves--Valves or sample splitters,or both, are required to permit switching, backflushing, or for simultaneous analysis. 5.11 Manometer--May be either U-tube type or well type equipped with an accurately graduated and easily read scale covering the range 0 to 900 mm (36 in.) of mercury or larger. The U-tube type is useful, since it permits filling the sample loop with up to two atmospheres of sample pressure, thus extending the range of all components. The well type inherently offers better precision and is preferred when calibrating with pure components. Samples with up to one

NOTE 3--The chromatogramsin Figs. 3 through 8 are only illustrations of typical separations. The operating conditions, including columns, are also typical and are subject to optimization by competent personnel. 5.9 Drier--Unless water is known not to interfere in the analysis, a drier must be provided in the sample entering system, ahead of the sample valve. The drier must remove

COLUMN:

2 meter Type 13X molecular sieve, 80-100 mesh

SAMPLE SIZE:

0.25 mL.

CARRIER GAS:

H e l i u m @ 30 mL./min.

Z

8 Z

Minutes FIG. 3

Separation Column for Oxygen, Nitrogen, and Methane (See Annex A2)

289

({~) D 1945

COLUMN-25% BMEE on Chromosorb P, 7 meters @ 25°C CARRIER GAS : Helium @ 40 mL./min. SAMPLE SIZE: 0.25 mL.

I

18

FIG. 4

'

;

16

'

;

I t _ ~ ~

'

14 12

I~

I

8

'

6

|

*

4

:

i

;

2

0

Minutes Chromatogramof Natural Gas (BMEE Column)(See Annex A2)

COLUMN:

ChromosorbPAW, 200/500, 10m

CARRIER GAS : Helium @ 40 mL./mln.

~[-4

'

t

t

30

25

20

15

|

~

|

i0

5

0

Minutes FIG. 5

Chromatogram

of Natural

Gas

(Silicone

atmosphere of pressure can be entered. With either type manometer the mm scale can be read more accurately than the inch scale. Caution should be used handling mercury because of its toxic nature. Avoid contact with the skin as much as possible. Wash thoroughly after contact. 5.12 Vacuum Pump--Must have the capability of producing a vacuum of 1 mm of mercury absolute or less.

2001500

Column)

(See

Annex

A2)

6. Preparation of Apparatus 6.1 Linearity Check--In order to establish linearity of response for the thermal conductivity detector, it is necessary to complete the following procedure: 6.l.l The major component of interest (methane for natural gas) is charged to the chromatograph by way of the fixed-size sample loop at partial pressure increments of 13 290

II~') D 1945 COLUMN:

DIDP-3meter +DMS-6meter @ 350C.

CARRIER GAS : Helium @ 75 mL./min. SAMPLE SIZE : 0.5 mL0

!

!

Z O

/k !

20

E-~ Z

/%

I

18

I

I

1

I

16

14

12

i0

!

!

6

4

I......

8

!

I

2

0

Minutes FIG. 6 Chromatogram of Natural Gas (See Annex A2)

COLIII'~ I:

3 m e t e r s x 3turn 152 S q u a | l n e Chromosorb PAt4, 8 0 - [ 0 o ~ s h .

COLUMN 2:

Z meters x ~ 80-100 n ~ s h .

COLU~CN 3:

2 m e t e r s x 3mm Holect, l a r S i e v e 5-A, 80.100 ~ e s h .

Porapak N

°l 1

i0A 4

FIG. 7

6

8

10

I

I

w

!

12

14

18

20

Chromatogram of Natural Gas (Multi-Column Application) (See Annex A2)

kPa (100 mm Hg) from 13 to I00 kPa (100 to 760 mm Hg) or the prevailing atmospheric pressure. 6.1.2 The integrated peak responses for the area generated at each of the pressure increments are plotted versus their partial pressure (see Fig. 9). 6.1.3 The plotted results should yield a straight line. A perfectly linear response would display a straight line at a 45*

angle using the logarithmic values. 6.1.4 Any curved line indicates the fixed volume sample loop is too large. A smaller loop size should replace the fixed volume loop and 6.1.1 through 6.1.4 should be repeated (see Fig. 9). 6.1.5 The linearity over the range of interest must be known for each component. It is useful to construct a table 291

~

D 1945 o

Z

2 meter x 3mm mol. sieve 13x @ 50 C Argon carrier @ 40 mL./min. Detector @ lO0m&.

I...4

!

5

!

4

I

3

2

I

I

1

0

Minutes FIG. 8 Separation of Helium and Hydrogen

sample valve to place the sample onto the column. Record the peak area of the pure component. 6.2.4 Repeat 6.2.3 for 26, 39, 52, 65, 78, and 91 id'a (200, 300, 400, 500, 600, and 700 mm Hg) on the manometer, recording the peak area obtained for sample analysis at each of these pressures. 6.2.5 Plot the area data (x axis) versus the partial pressures (y axis) on a linear graph as shown in Fig. 9. 6.2.6 An alternative method is to obtain a blend of all the components and charge the sample loop at partial pressure over the range of interest. If a gas blender is available the mixture can be diluted with methane thereby giving response curves for all the components.

noting the response factor deviation in changing concentration. (See Table 2 and 3). 6.1.6 It should be noted that nitrogen, methane, and ethane exhibit less than 1% compressibility at atmospheric pressure. Other natural gas components do exhibit a significant compressibility at pressures less than atmospheric. 6.1.7 Most components that have vapor pressures of less than 100 kPa (15 psia) cannot be used as a pure gas for a linearity study because they will not exhibit sufficient vapor pressure for a manometer reading to 100 kPa (760 mm Hg). For these components, a mixture with nitrogen or methane can be used to establish a partial pressure that can extend the total pressure to 100 kPa (760 mm Hg). Using Table 4 for vapor pressures at 38°C (100°F), calculate the maximum pressure to which a given component can be blended with nitrogen as follows: B = 000 x V)li (2) P = (i x M)IIO0 (3)

NOTe 5: Caution--If it is not possible to obtain information on the linearity of the available gas chromatograph detector for all of the test gas components, then as a minimum requirement the linearity data must be obtained for any gas component that exceeds a concentration of 5 tool %. Chromatographs are not truly linear over wide concentration ranges and iinearity should be established over the range of interest.

where: B = blend pressure, max, kPa (ram Hg), V ffi vapor pressure, kPa (ram Hg), i - tool % P -- partial pressure, kPa (ram Hg), and M ffi manometer pressure, kPa (ram Hg). 6.2. Procedure for Linearity Check: 6.2.1 Connect the pure-component source to the sampleentry system. Evacuate the sample-entry system and observe the manometer for leaks. (See Fig. 1 for a suggested manifold arrangement.) The sample-entry system must be vacuum tight. 6.2.2 Carefully open the needle valve to admit the pure component up to 13 kPa (100 mm Fig) of partial pressure. 6.2.3 Record the exact partial pressure and actuate the

7. Reference Standards 7.1 Moisture-free gas mixtures of known composition are required for comparison with the test sample. They must contain known percents of the components, except oxygen (Note 6), that are to be determined in the unknown sample. All components in the reference standard must be homogenous in the vapor state at the time of use. The concentration of a component in the reference standard gas should not be less than one half nor more than twice the concentration of the corresponding component in the test gas. NoTe 6--Unless the referencestandard is stored in a containerthat has been tested and proved for inertness to oxygen,it is preferable to calibrate for oxygenby an alternativemethod. 292

~ ) D 1945

800

700

60C

~. E E

5oo

3OC

2oc

lO(

10,000

50,000 /Yea Count

30.000

TABLE 3

Linearity Evaluation o f M e t h a n e

S mole %

S/B mole ~/arse

223119392 242610272 261785320 280494912 299145504 317987328 336489056 351120721

51 56 61 66 71 76 81 85

2.2858e-07 2.3082e-07 2.3302e-07 2.3530e-07 2.3734e-07 2.3900e-07 2.4072e-07 2.4208e-07

Lineadty Evaluation f o r Nitrogen

S/B diff - (low mole ~ - hig~ mole S)/Iow rnole ~ x 100

S/B diff = (low mole % - high mole Y,)/Iow mole % x 100 B area

I iv,~00

Linoarity of Detector Response

FIG. 9 TABLE 2

tN,Ut*V

TO,i.'UU

S/B diff., % on low value -0.98 -0.95 -0.98 -0.87 -0.70 -0.72 -0.57

B area

S mole ~

5879836 29137066 57452364 84953192 111491232 137268764 162852288 187232496

1 5 10 15 20 25 30 35

TABLE 4

7.2 Preparation--A reference standard may be prepared by blending pure components. Diluted dry air is a suitable standard for oxygen and nitrogen (see 8.5.1 ):,6

Component Nitrogen Methane Carbon dioxide Ethane Hydrogen sulfide Propane Isobutane n-Butane Isopentane n-Pentane n-Hexane n-Heptane

8. Procedure 8.1 Instrument Preparation--Place the proper column(s) in operation as needed for the desired run (as described in either 8.4, 8,5, or 8.6). Adjust the operating conditions and s A suitablereference standard is available from PhillipsPetroleum Co., Borger, T X 79007. A ten-component reference standard traceable to the National Institute of Standards and Technology (NIST) is available from Institute of Gas Technology (IGT), 3424 S. State St., Chicago, IL 60616.

S/B mole Y,/area S/B diff., • on low value 1.7007e-07 1.7160e-07 1.7046e-07 1.76570-07 1.79390-07 1.82120-07 1.8422e-07 1.8693e-07

-0.89 - 1.43 -1.44 -1.60 - 1.53 -1.15 -1.48

Vapor Pr essur e at 3 8 ° C ( 1 0 0 ° F ) A kPa absolute >34 >34 >5 >5 2 1

500 500 520 520 720 300 501 356 141 108 34.2 11.2

psia >5 000 >5 000 >800 >800 395 189 72.6 51.7 20.5 15.6 4.96 1.62

A The most recent data for the vapor pressures listed are available from the Thermodynamics Research Center, Texas A&M University System, College Station, TX 77843.

293

~ ) D 1945 absolute pressure. Close the valve to the vacuum source and carefully meter the fuel-gas sample from the sample cylinder until the sample loop is filled to the desired pressure, as indicated on the manometer (see Fig. 1). Inject the sample into the chromatograph. 8.4 Partition Column Run for Ethane and Heavier Hydrocarbons and Carbon Dioxide --This run is made using either helium or hydrogen as the carrier gas; if other than a thermal conductivity detector is used, select a suitable carrier gas for that detector. Select a sample size in accordance with 8.1. Enter the sample, and backflush heavy components when appropriate. Obtain a corresponding response on the reference standard. 8.4.1 Methane may also be determined on this column if the column will separate the methane from nitrogen and oxygen (such as with silicone 200/500 as shown in Fig. 5), and the sample size does not exceed 0.5 mL. 8.5 Adsorption Column Run for Oxygen, Nitrogen, and Methane--Make this run using helium or hydrogen as the carrier gas. The sample size must not exceed 0.5 mL for the determination of methane. Enter the sample and obtain a response through methane (Note 6). Likewise, obtain a response on the reference standard for nitrogen and methane. Obtain a response on dry air for nitrogen and oxygen, if desired. The air must be either entered at an accurately measured reduced pressure, or from a helium-diluted mixture. 8.5. I A mixture containing approximately 1% of oxygen can be prepared by pressurizing a container of dry air at atmospheric pressure to 2 MPa (20 atm) with pure helium. This pressure need not be measured precisely, as the concentration of nitrogen in the mixture thus prepared must be determined by comparison to nitrogen in the reference standard. The percent nitrogen is multiplied by 0.268 to obtain the mole percent of oxygen, or by 0.280 to obtain the mole percent total of oxygen and argon. Do not rely on oxygen standards that have been prepared for more than a few days. It is permissible to use a response factor for oxygen that is relative to a stable constituent. 8.6 Adsorption Column Run for Helium and Hydrogen-Make this run using either nitrogen or argon as the carrier gas. Enter a 1 to 5-mL sample and record the response for helium, followed by hydrogen, which will be just ahead of oxygen (Note 6). Obtain a corresponding response on a reference standard containing suitable concentrations of helium and hydrogen (see Fig. 8).

allow the chromatograph to stabilize. 8. I. 1 For hexanes and higher, heat the sample loop. Note 7--Most modern chromatographshave valve ovens that can be temperature controlled.It is stronglyrecommendedin the absence of valveovensto mount the gas samplingvalvein the chromatographoven and operate at the column temperature. 8.1.2 After the instrument has apparently stabilized, make check runs on the reference standard to establish instrument repeatability. Two consecutive checks must agree within 1% of the amount present of each component. Either the average of the two consecutive checks, or the latest check agreeing within 1% of the previous check on each component may be used as the reference standard for all subsequent runs until there is a change in instrument operating conditions. Daily calibrations are recommended. 8.2 Sample Preparation--lfdesired, hydrogen sulfide may be removed by at least two methods (see Annex A2.3). 8.2.1 Preparation and Introduction of Sample--Samples must be equilibrated in the laboratory at 20-50"F above the source temperature of the field sampling. The higher the temperature the shorter the equilibration time (approximately two hours for small sample containers of 300 mL or less). This analysis method assumes field sampling methods have removed entrained liquids. If the hydrocarbon dewpoint of the sample is known to be lower than the lowest temperature to which the sample has been exposed, it is not necessary to heat the sample. 8.2.2 Connections from the sample container to the sample inlet of the instrument should be made with stainless steel or with short pieces of TFE-fluorocarbon. Copper, vinyl, or rubber connections are not acceptable. Heated lines may be necessary for high hydrocarbon content samples. 8.3 Sample Introduction--The size of the sample introduced to the chromatographic columns shall not exceed 0.5 mL. (This small sample size is necessary to obtain a linear detector response for methane.) Sufficient accuracy can be obtained for the determination of all but the minor constituents by the use of this sample size. When increased response is required for the determination of components present in concentrations not exceeding 5 tool %, it is permissible to use sample and reference standard volumes not exceeding 5 mL. (Avoid introduction of liquids into the sample system.) 8.3.1 Purging MethodmOpen the outlet valve of the sample cylinder and purge the sample through the inlet system and sample loop or tube. The amount of purging required must be established and verified for each instrument. The sample loop pressure should be near atmospheric. Close the cylinder valve and allow the pressure of the sample in the loop or tube to stabilize. Then immediately inject the contents of the loop or tube into the chromatographic column to avoid infiltration of contaminants. 8.3.2 Water Displacement--If the sample was obtained by water displacement, then water displacement may be used to purge and fill the sample loop or tube.

9. Calculation

NOTE 8: Caution--Somecomponents, such as carbon dioxide, hydrogen sulfide,and hexanesand higherhydrocarbons,may be partially or completelyremovedby the water.

8.3.3 Evacuation Method--Evacuate the charging system, including the sample loop, and the sample line back to the valve on the sample cylinder, to less than 0.1 kPa (1 mm Hg) 294

9.1 The number of significant digits retained for the quantitative value of each component shall be such that accuracy is neither sacrificed or exaggerated. The expressed numerical value of any component in the sample should not be presumed to be more accurate than the corresponding certified value of that component in the calibration standard. 9.2 External Standard Method: 9.2.1 Pentanes and Lighter Components--Measure the height of each component peak for pentanes and lighter, convert to the same attenuation for corresponding components in the sample and reference standard, and calculate the concentration of each component in the sample as follows: C ffi S x (A/B) (4)

~

D 1945 9.2.4.1 If the mole percent of iC5 + nC5 has been determined by a separate run with a smaller sized sample, this value need not be redetermined. 9.2.5 The entire reverse flow area may be calculated in this manner as C6 and heavier, or as C5 and heavier should the carrier gas reversal be made after n-butane. The measured area should be corrected by using the average molecular weights of the entire reverse-flow components for the value of A. The mole percent and area of the iC5 and nC5 reverse flow peak of an identically sized sample of reference standard (free of (26 and heavier) shall then be used for calculating the final mole percent value. 9.2.6 Normalize the mole percent values by multiplying each value by 100 and dividing by the sum of the original values. The sum of the original values should not differ from 100.0 % by more than 1.0 %. 9.2.7 See sample calculations in Appendix X2.

where: C = component concentration in the sample, mol %, A = peak height of component in the sample, mm, B = peak height of component in the standard, mm, and S = component concentration in the reference standard, tool %. 9.2.1.1 If air has been run at reduced pressure for oxygen or nitrogen calibration, or both, correct the equation for pressure as follows: C = S x (A/B) x (Pa/Pb) (5) where: Pa --- pressure at which air is run, and Pb = true barometric pressure during the run, with both pressures being expressed in the same units. 9.2.1.2 Use composition values of 78.1% nitrogen and 21.9 % oxygen for dry air, because argon elutes with oxygen on a molecular sieves column under the normal conditions of this test method. 9.2.2 Hexanes and Heavier Components--Measure the areas of the hexanes portion and the heptanes and heavier portion of the reverse-flow peak (see Annex A l, Fig. A I.I, and Appendix X3.6). Also measure the areas of both pentane peaks on the sample chromatogram, and adjust all measured areas to the same attenuation basis. 9.2.3 Calculate corrected areas of the reverse flow peaks as follows: Corrected C6 area ffi 72/86 x measured C6 area (6) Corrected C7 and heavier area = 72/A x measured C7 and heavier area (7)

10. Precision 10.1 Precision--The precision of this test method, as determined by the statistical examination of the interlaboratory test results, for gas samples of pipeline quality 38 MJ/m 3 (1000 Btu/SCF) is as follows: 10.1.1 RepeatabzTity--The difference between two successive results obtained by the same operator with the same apparatus under constant operating conditions on identical test materials should be considered suspect if they differ by more than the following amounts:

where A -- average molecular weight of the C7 and heavier fraction.

Component, mol %

Repeatability

0 to 0.1 0.1 to 1.0 1.0 to 5.0 5.0 to I0 Over 10

0.01 0.04 0.07 0.08 0.10

10.1.2 Reproducibility--The difference between two results obtained by different operators in different laboratories on identical test materials should he considered suspect if they differ by more than the following amounts:

NOTE 9--The value of 98 is usually sufficiently accurate for use as the C7 and heavier fraction average molecular weight; the small amount of Ca and heavier present is usually offset by the lighter methyl cyclopentane and cyclobexane that occur in this fraction. A more accurate value for the molecular weight of C7 and heavier can be obtained as described in Annex AI.3. 9.2.4 Calculate the concentration of the two fractions in the sample as follows: Mol % C6 = (corrected C6 area) x (mol % iCs + nCs)/(iC5 + nCs area). (8) Mol % C7+ = (corrected C7 area) x (tool % iC5 + nC5)/(iC5 + nC5 area). (9)

Component, mol %

Reproducibility

0 to 0.1 0. I to 1.0 1.0 to 5.0 5.0 to 10 Over 10

0.02 0.07 0.10 0.12 0.15

11. Keywords 11.1 gas analysis; gas chromatography; natural gas composition

ANNEXES

(Mandatory Information) A1. S U P P L E M E N T A R Y P R O C E D U R E S

AI.I Analysis for only Propane and Heavier Components

another partition column that will separate propane through n-pentane in about 5 min. Enter a 1 to 5-mL sample into the column and reverse the carder gas flow after n-pentane is separated. Obtain a corresponding chromatogram on the reference standard, which can be accomplished in about 5min run time, as there is no need to reverse the flow on the reference standard. Make calculations in the same manner as for the complete analysis method.

AI.I.I This determination can be made in I0 to 15-rain run time by using column conditions to separate propane, isobutane, n-butane, isopentane, n-pentane, hexanes and heptanes, and heavier, but disregarding separation on ethane and lighter. A I.I.2 Use a 5-m bis-(2(2-methoxyethoxy) ethyl)ether (BMEE) column at about 30°C, or a suitable length of 295

~

D 1945

¢¢1

+

O

201'

~" /m:i.n .---~ FIG. A1.1

8

14 ½"/min.

2 -- l " / m i n .

0 I

Composition of Hexanes and Heavier Fraction

A l.l.3 A determination of propane, isobutane, n-butane, and pentanes and heavier can be made in about 5-min run time by reversing the carder-gas flow after n-butane. However, it is necessary to know the average molecular weight of the pentanes and heavier components.

AI.2 Single-run Analysis for Ethane and Heavier Components A 1.2.1 In many cases, a single partition run using a sample size in the order of 1 to 5 mL will be adequate for determining all components except methane, which cannot be determined accurately using this size sample with peak height measurements, because of its high concentration. AI.2.2 Enter a 1 to 5-mL sample into the partition column and reverse the carrier gas flow after n-pentane is separated. Obtain a corresponding chromatogram of the reference standard. Measure the peak heights of ethane through n-pentane and the areas of the pentane peaks of the standard. Make calculations on ethane and heavier components in the same manner as for the complete analysis method. Methane and lighter may be expressed as the difference between 100

and the sum of the determined components. AI.3 Special Analysis to Determine Hexanes and Heavier Components AI.3.1 A short partition column can be used advantageously to separate heavy-end components and obtain a more detailed breakdown on composition of the reverse-flow fractions. This information provides quality data, and a basis for calculating physical properties such as molecular weight on these fractions. A 1.3.2 Figure A I. l is a chromatogram that shows components that are separated by a 2-m BMEE column in 20 min. To make this determination, enter a 5-mL sample into the short column and reverse the carrier gas after the separation of n-heptane. Measure areas of all peaks eluted after n-pentane. Correct each peak area to the mol basis by dividing each peak area by the molecular weight of the component. A value of 120 may be used for the molecular weight of the octanes and heavier reverse-flow peak. Calculate the mole percent of the hexanes and heavier components by adding the corrected areas and dividing to make the total 100 %.

A2. PREPARATION OF COLUMNS AND DRIER A2.1 Preparation of Columns--See Practice E 260. A2.2 Preparation of Drier--Fill a 10-mm diameter by 100-mm length glass tube with granular phosphorus pentoxide or magnesium perchlorate, observing all proper safety precautions. Mount as required to dry the sample. Replace the drying agent after about one half of the material has become spent. A2.3 Removal of Hydrogen Sulfide: A2.3.1 For samples containing more than about 300 ppm by mass hydrogen sulfide, remove the hydrogen sulfide by connecting a tube of sodium hydrate absorbent (Ascarite)

ahead of the sample container during sampling, or ahead of the drying tube when entering the sample into the chromatograph. This procedure also removes carbon dioxide, and the results obtained will be on the acid-gas free basis. A2.3.2 Hydrogen sulfide may also be removed by connecting a tube of pumice that has been impregnated with cupric sulfate in the line upstream of both the chromatograph and drying tube. This procedure will remove small amounts of hydrogen sulfide while having but minimal effect on the carbon dioxide in the sample. A2.4 Column Arrangement--For analyses in which 296

~

V 1945

LONG PARTITION COLUMN SHOR~o[~ITION (For• Spplementary Use Only) ABSORPTION COLUMN

~v/1

- TO

v_

i TO DETECTOR

FIG. A2.1

Column Arrangement

column lengths, by using them either singly or in series. The connection between V~ and V2 in Fig. A2.1 should be as short as possible (20 mm is practical) to minimize dead space between the columns when used in series. If all columns are chosen to operate at the same temperature, then stabilization time between changing columns will be minimized.

hexanes and heavier components are to be determined, Fig. A2.1 shows an arrangement whereby columns can be quickly and easily changed by the turn of a selector valve. Two columns are necessary to determine all of the components covered in this test method. However, short and long partition columns provide the flexibility of three partition

APPENDIXES (Nonmandatory Information)

X1. REFERENCE STANDARD MIXTURE

Cylinder, 20-L Pressure Cylinders, two 100-mL (A and B) Balance, 2000-g capacity, sensitivity of 10 rag. Pure Components, methane through n-pentane, and carbon

XI.I Preparation X 1.1.1 Gas mixtures of the following typical compositions will suffice for use as reference standards for most analytical requirements (Note X 1.1): Component Helium Hydrogen Nitrogen Methane (maximum) Ethane Carbon dioxide Propane Isobutane n-Butane neopentane Isopentane n.pentane Hexanes +

Lean gas, mol %

Rich gas, mol %

1.0 3.0 4.0 85 6.0 1.0 4.0 2.0 2.0 0.5 0.5 0.5 0.1

0.5 0.5 0.5 74 tO 1.0 7.0 3.0 3.0 !.0 1.0 1.0 0.2

dioxide. The pure components should be 99+ % pure. Methane should be in a I-L cylinder at 10 MPa (100-atm) pressure. Run a chromatogram of each component to check on its given composition. X1.1.2.2 Evacuate the 20-L cylinder for several hours. Evacuate 100-mL Cylinder A, and obtain its true weight. Connect Cylinder A to a cylinder of pure n-pentane with a metal connection of calculated length to contain approximately the amount of n-pentane to be added. Flush the connection with the n-pentane by loosening the fitting at the valve on Cylinder A. Tighten the fitting. Close the n-pentane cylinder valve and open Cylinder A valve to admit the n-pentane from the connection and then close the valve on Cylinder A. Disconnect and weigh Cylinder A to obtain the weight of n-pentane added. X1.1.2.3 Similarly, add isopentane, n-butane, isobutane, propane, ethane, and carbon dioxide, in that order, as desired, in the reference standard. Weigh Cylinder A after each addition to obtain the weight of the component added. Connect Cylinder A to the evacuated 20-L cylinder with as

NOTE X l.l--If the mixture is stored under pressure, take care to ensure that the partial pressure of any component does not exceed its vapor pressure at the temperature and pressure at which the sample is stored and used. The Lean mixturehas a ericondenthermat 60"F and the Rich mixture has a ericondenthermat 100°F. X l.I.2 A useful method for preparation of a reference standard by weight is as follows:5 X i. 1.2.1 Obtain the following equipment and material:

297

~) D 1945 I BUTANE

984515 9GG4JLG

A

?58917

R

E A

(;11488

4£&037

314649

1.59383

I

0.150

11.3N

g.450

6.6N

I

0.758

I

I

8 . SgiJ 1 . IKNi

Mole % FIG. X1.1 TABLE X1.1

sum -

Example of Deriving • Relative Molar Response Factor

Cylinder B to obtain the weight of the mixture that was not transferred to the 20-L cylinder. X I. 1.2.5 Weigh a I-L cylinder containing pure methane at about 10-MPa (100-atm) pressure. Transfer the methane to the 20-L cylinder until the pressure equalizes. Weigh the I-L cylinder to determine the weight of methane transferred. X1.1.2.6 Thoroughly mix the contents of the 20-L cylinder by heating at the bottom by a convenient means such as hot water or a heat lamp, and leaving the cylinder in a vertical position for at least 6 h. X1.1.2.7 Use the weights and purities of all components added to calculate the weight composition of the mixture. Convert the weight percent to mole percent.

Least Square Calculation for Slope of iso-Butane area Y

mole ~t X

984515 900410 758917 611488 466037 314649 159303

1 0.9 0.75 0.6 0.45 0.3 0.15

4195319

4.15

slope =

ZXY/2;Y ~

XY 984515 810369 569187.75 366892.8 209716.65 94394.7 23895.45

y2 9.693e+ 11 8.107e+ 11 5.670e+11 3.7390+ 11 2.172o+11 9.9000+10 2.538o+10

3058971.35 3.071452e+12 9.95940-07

short a clean, small-diameter connector as possible. Open the valve on the 20-L cylinder, then open the valve on Cylinder A. This will result in the transfer of nearly all of the contents of Cylinder A into the 20-L cylinder. Close the cylinder valves, disconnect, and weigh Cylinder A to determine the weight of mixture that was not transferred to the 20-L cylinder. X1.1.2.4 Evacuate and weigh 100-mL Cylinder B. Then fill Cylinder B with helium and hydrogen respectively to the pressures required to provide the desired concentrations of these components in the final blend. (Helium and hydrogen are prepared and measured separately from the other components to prevent their pressures, while in the 100-mL cylinder, from causing condensation of the higher hydrocarbons.) Weigh Cylinder B after each addition to obtain the weight of the component added. Connect Cylinder B to the 20-L cylinderwith as short a clean,small-diameter connector as possible.Open the valve on the 20-L cylinder, then open the valve on Cylinder B, which will result in the transfer of nearly all of the contents of Cylinder B into the 20-L cylinder. Close the cylinder valves, disconnect, and weigh

X1.2 Calibration with Pure Components X 1.2.1 Use helium carrier gas to admit a sample volume of 0.25 to 0.5 mL into the adsorption column, providing methane at 50 kPa (375 mm Hg) and nitrogen at 10 kPa (75 mm Hg) absolute pressure. Run a sample of the standard mixture at 70 kPa (525 mm Hg) pressure, and obtain peaks for methane and nitrogen. NOTE XI.2--Each run made throughout this procedure should be repeated to ensure that peak heights are reproducible after correction for

pressuredifferencesto within I mm or 1% of the mean value.All peaks should be recorded at an instrument attenuationthat gives the maximum measurablepeak height. XI.2.2 Change the carrier gas to argon or nitrogen and, after the base line has stabilized, enter a sample of pure helium at 7 kPa (50 mm Hg) absolute pressure, recording the peak at an attenuation that allows maximum peak height. Run a sample of the mixture at 70 kPa (525 mm Hg) absolute pressure, and obtain the helium peak. X1.2.3 Switch to the partition column with helium carrier gas, and run the gas mixture at 70 kPa (525 mm Hg) absolute 298

(@) D 1945 TABLE X l . 2 Comp. Nitrogen Methane Ethane Propane Carbon Dioxide iso-Butane n-Butane neopentane iso-Pantane n-Pentane Hexanes +

Calculation of Response Factors Using Relative Molar Response Values

Mole ~; in Refarence Standard S

Response of Reference Standard B

Response Factor From Reference Standard S/B,K

5.08 82.15 8.75 4.02

2685885 36642384 6328524 3552767

1.8914E-6 2.2419E-6 1.3826E-6 1.1315E-6

Relative MolarA Response from Slope]K~ RMR=

Response Factor

1.11607,., 0.72958= 0.693100a 0.68271 ca 0.63874~ 0.60041= 0.54762~

1.5429E-6 9.9594E-7 9.1142E-7 8.9776E-7 8.3994E-7 7.8953E-7 7.2012E-7

of Referenced Components (RMR~)x(K,)

A The Relative Molar Response is a constant that is calculated by dividing the slope of the referenced component by the component that ts present in the referance standard. For example: RMR~, = (slope/c4)/(Kca)= 9.9594E-7 1.1315E-6 = 0.72958

pressure. Then admit samples of pure ethane and propane at 10 kPa (75 mm Hg) absolute pressure, and butanes, pentanes, and carbon dioxide at 5 kPa (38 mm Hg) absolute pressure. XI.2.4 Run the gas mixture at 70 kPa (525 mm Hg) absolute pressure. XI.2.5 Calculate the composition of the prepared gas mixture as follows: XI.2.5.1 Correct peak heights of all pure components and the respective components in the blend to the same attenuation (Note X 1.2). Xl.2.5.2 Calculate the concentration of each component as follows:

30 %, and 15 % of absolute pressure. For 100 kPa (760 mm Hg) the pressures used are 90 kPa (684 mm Hg), 75 kPa (570 mm Hg), 60 kPa (456 mm Hg), 45 Kpa (342 mm Hg), 30 kPa (228 mm Hg), 15 kPa (114 mm Hg). X1.3.4 Plot the area or height (attenuated at the same height as the reference component) versus concentration and calculate the slope of the line by the least squares method. Given the equation of the line as Y = ao + a ~ X where Y represents the area or height points and X the concentration points. The line is assumed to intersect through the origin and ao = 0. The slope a~ can be calculated by: xXy

al = (Zy)2

(Xl.l)

c = (~OOV:)(AIB)fPdP,,) XI.3.5 Ratio the slopes of the referenced components (i) to the slopes of the reference components (r) present in the daily calibration standard. This gives the Relative Molar Response factor (RMRI) for component (i). The reference component must be present in the same instrumental sequence (except Hexanes +) as the referenced components. For instance, propane can be the reference component for the butanes and pentanes if propane is separated on the same column in the same sequence as the butanes and pentanes. Ethane can be the reference component for carbon dioxide if it elutes in the same sequence as carbon dioxide. The hexanes + peak can be referenced to propane or calculated as mentioned in the body of the standard. X 1.3.6 For daily calibration a four component standard is used containing nitrogen, methane, ethane, and propane. The fewer components eliminates dew point problems, reactivity, is more accurate and can be blended at a higher pressure. The referenced components' response factors are calculated from the current reference factor and the Relative Molar Response factor. Following is a description of the basic calculations, an example of deriving a Relative Molar Response factor (Fig. X I.I), and a table showing how response factors are calculated (Table XI.2).

where: component concentration, mol %, peak height of component in blend, peak height of pure component, Pa= pressure at which blend is run, kPa (mm Hg), P~= pressure at which component is run, kPa (mm Hg), and re= volume fraction of pure component.

C= A = B =

NOTE X I . 3 - - V f = !.000 if the calibration component is free of impurities.

X1.2.5.3 Normalize values to 100.0 %. Xl.3 Calibration using Relative Molar Response Values I "3 1 r J ~I^~." . . . . . . . . . . . . *: . . . . . -. J_-2_._ A,.J.i ,',~lauvc ,car,u - ~ ,=t, ua ~ . luc uc,vcd from linearity data and used for calculating response factors. This eliminates the need for a multi-component standard for daily calibration. The test method can be dsed on any gas chromatograph using a thermal conductivity or thermistor detector. XI.3.2 Obtain a blend that brackets the expected concentration the instrument will be analyzing. The major component (methane) is used as the balance gas and may fall below the expected concentration. This component is present in the daily calibration standard and linearity is assured from previous tests. XI.3.3 Inject the sample at reduced pressures using the apparatus in Fig. 1 or using a mechanical gas blender. Obtain repeatable peak areas or height at 90 %, 75 %, 60 %, 45 %, V

Mole % Response Factor (R) -- Area ' Relative Molar Response (RMRi) = Mole %(i)/Area(i) Mole %(r)/Area(r) RIc 4 = R M R i c 4 X R ~

299

(XI.2)

(X1.3) (Xl.4)

~1~) D 1945 these operating conditions, all of the components will be affected equally and the calculated response factors will shift accordingly. See Table XI.I and Figs. XI.I and XI.2.

X 1.3.7 Periodic checks of the RMR relationship is recommended. The relationship is independent of temperature, sample size, and carrier gas flow rate. If changes occur in

X2. SAMPLE CALCULATIONS (SEE SECTION 9) TABLE X2.1 Component Helium Hydrogen Oxygen Nitrogen Methane Ethane Carbon dioxide Propane Isobutarm n-Butane neopentane Isopentans n-Pentane Hexanes + o

Sample Calculations

Mol ~ in Reference Standard, S

Response of Reference Standard, B

Response Factor. S/B

Response for Sample,A A

Percent C - (S x A)/B

0.50 0.74 0.27 4.89 70.27 9.07 0.98 6.65 2.88 2.87 0.59 0.87 0.86

41.1 90.2 35.5 77.8 76.4 96.5 57.5 55.2 73.2 60.3 10.4 96.0 86.8

0.0122 0.0082 0.0076 0.0629 0.9198 0.0940 0.0170 0.1205 0.0393 0.0476 0.0567 0.0091 0.0099

12.6 1.5 2.1 75.6 90.4 79.0 21.2 20.6 11.0 15.0 0.1 24.0 20.5 72.1"

0.154 0.012 0.016 4.755 83.150 7.426 0.360 2.482 0.432 0.714 0.006 0.218 0.203 0.166 c

Normalized, 0.15 0.01 0.02 4.75 83.07 7.42 0.36 2.48 0.43 0.71 0.01 0.22 0.20 0.17 100.00 %

A The response for a constituent in the sample has been corrected to the same attenuation as for that constituent in the reference standard. e Corrected Ca response ffi (original response of 92.1) x (72/92) = 72.1. c Mol % Ca+ ffi (0.218 + 0.203) x (72.1)/(96.0 + 86.8) = 0.166. %/(3s ~ nCe Areas/C + nC6 o Average molecular weight of Cs+ - 92.

X3. PRECAUTIONS FOR AVOIDING COMMON CAUSES OF ERRORS both, are to be taken, use completely dry sample cylinders, connections, and lines, as moisture will selectively absorb appreciable amounts of the acid gases. If hydrogen is present, use aluminum, stainless steel, or other materials inert to hydrogen sulfide for the cylinder, valves, lines, and connections.

X3.1 Hexane and Heavier Content Change X3.1.1 The amounts of heavy-end components in natural gas are easily changed during handling and entering of samples to give seriously erroneous low or high values. Concentration of these components has been observed to occur in a number of cases because of collection of heavier components in the sample loop during purging of the system. The surface effect of small diameter tubing acts as a separating column and must not be used in the sampling and entering system when components heavier than pentanes are to be determined. An accumulation of oily film in the sampling system greatly aggravates this problem. Also, the richer the gas, the worse the problem. Periodically, check C6 and heavier repeatability of the apparatus by making several check runs on the same sample. It is helpful to retain a sample containing some hexanes and heavier for periodic checking. When enlargement of the heavy end peaks is noted, thoroughly clean the sampling valve and loop with acetone. This trouble has been experienced with some inlet systems even when clean and with the specified sample loop size. This contamination can be minimized by such techniques as purging with inert gas, heating the sample loop, using a vacuum system, or other such effective means.

X3.3 Sample Dew Point X3.3.1 Nonrepresentative samples frequently occur because of condensation of liquid. Maintain all samples above the hydrocarbon dew point. If cooled below this, heat 10"C or more above the dew point for several hours before using. If the dew point is unknown, heat above the sampling temperature. X3.4 Sample Inlet System X3.4.1 Do not use rubber or plastic that may preferentially adsorb sample components. Keep the system short and the drier small to minimize the purging required. X3.5 Sample Size Repeatability X3.5.1 Varying back pressures on the sample loop may impair sample size repeatability. X3.5.2 Make it a practice to make all reverse flow determinations in the same carrier gas flow direction. All single-peak determinations and corresponding reference runs will then be made in the same carrier gas flow direction. X3.5.3 Be sure that the inlet drier is in good condition.

X3.2 Acid Gas Content Change X3.2. l The carbon dioxide and hydrogen sulfide contents of gas are easily altered during sampling and handling. If samples containing carbon dioxide or hydrogen sulfide, or 300

~

D 1945 fixed zero line as the base line, but use the actual observed base line. On high sensitivity, this base line may drift slightly without harm and it need not frequently be moved back to zero. A strip chart recorder with an offset zero is desirable. The area of reverse flow peak may be measured by planimeter or geometric construction. The reverse flow area, and the pcntanes peaks used for comparison should be measured by the same method. That is, use either geometric construction or planimeter, but do not intermix. When a planimeter is used, carefully make several tracings and use the average. Check this average by a second group of tracings.

Moisture on the column will enlarge the reverse flow peak. X3.5.4 Be sure the column is clean by occasionally giving it several hours sweep of carder gas in reverse flow direction. A level base line should be quickly attained in either flow direction if the column is clean. X3.5.5 When the reverse flow valve is turned there is a reversal of pressure conditions at the column ends that upsets the carder gas flow. This flow should quickly return to the same flow rate and the base line level out. If it does not, the cause may be a leak in the carder gas system, faulty flow regulator, or an unbalanced condition of the column or plumbing.

X3.8 Miscellaneous X3.8.1 Moisture in the carder gas that would cause trouble on the reverse flow may be safeguarded against by installing a cartridge of molecular sieves ahead of the instrument. Usually 1 m of 6-mm tubing packed with 30 to 60-mesh molecular sieves is adequate, if changed with each cylinder of carder gas. X3.8.2 Check the carder gas flow system periodically for leaks with soap or leak detector solution. X3.8.3 Use electrical contact cleaner on the attenuator if noisy contacts are indicated. X3.8.4 Peaks with square tops with omission of small peaks can be caused by a sluggish recorder. If this condition cannot be remedied by adjustment of the gain, check the electronics in the recorder.

X3.6 Reference Standard X3.6.1 Maintain the reference standard at +15 *C or a temperature that is above the hydrocarbon dew point. If the reference standard should be exposed to lower temperatures, heat at the bottom for several hours before removing a sample. If in doubt about the composition, check the n-pentane and isopentane values with pure components by the procedure prescribed in Annex A2. X3.7 Measurements X3.7.1 The base line and tops of peaks should be plainly visible for making peak height measurements. Do not use a

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision st any time by the responsible technical committee and must be reviewed every five years and ff not revised, either reepproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend, ff you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 100 Berr Harbor Drive, West Conshohecken, PA 19428.

301

( ~ l ~ Designation: D 1946- 90 (Reapproved 1994) ~1 Standard Practice for Analysis of Reformed Gas by Gas Chromatography 1 This standard is issued under the fixed designation D 1946; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (+) indicates an editorial change since the last revision or reapproval. ~ Nor~--Section 12 was added in December 1994.

1. Scope 1.1 This practice covers the determination of the chemical composition of reformed gases and similar gaseous mixtures containing the following components: hydrogen, oxygen, nitrogen, carbon monoxide, carbon dioxide, methane, ethane, and ethylene. 1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

2. Referenced Document

2.1 ASTM Standard: E 260 Practice for Packed Column Gas Chromatography2 3. Summary of Practice 3.1 Components in a sample of reformed gas are physically separated by gas chromatography and compared to corresponding components of a reference standard separated under identical operating conditions, using a reference standard mixture of known composition. The composition of the reformed gas is calculated by comparison of either the peak height or area response of each component with the corresponding value of that component in the reference standard. 4. Significance and Use 4.1 The information about the chemical composition can be used to calculate physical properties of the gas, such as heating (calorific) value and relative density. Combustion characteristics, products of combustion, toxicity, and interchangeability with other fuel gases may also be inferred from the chemical composition. 5. Apparatus 5.1 Detector--The detector shall be a thermal conductivity type, or its equivalent in stability and sensitivity. The thermal conductivity detector must be sufficiently sensitive to produce a signal of at least 0.5 mV for l mol % methane in a 0.5-mL sample. 5.2 Recording Instruments--Either strip chart recorders i This practice is under the jurisdiction of ASTM Committee D-3 on Gaseous Fuels and is the direct responsibility of Subcommittee D03.07 on Analysis of Chemical Composition of Gaseous Fuels. Current edition approved March 30, 1990. Published May 1990. Originally published as 1946 - 62 T. Last previous edition D 1946 - 82. 2 Annual Book of ASTM Standards, Vol 14.02.

302

or electronic integrators, or both, are used to display the separated components. Although a strip chart recorder is not required when using electronic integration, it is highly desirable for evaluation of instrument performance. 5.2.1 The recorder, when used, shall be a strip chart recorder with a full-range scale of 5 mV or less (1 mV preferred). The width of the chart shall be not less than 150 mm. A maximum pen response time of 2 s (1 s preferred) and a minimum chart speed of 10 mm/min shall be required. Faster speeds up to 100 mm/min are desirable if the chromatogram is to be interpreted using manual methods to obtain areas. 5.2.2 Electronic or Computing Integrators--Proof of separation and response equivalent to that for the recorder is required for displays other than by chart recorder. 5.3 Attenuator--If manual methods are used to interpret the chromatogram, an attenuator must be used with the detector output signal to keep the peak maxima within the range of the recorder chart. The attenuator must be accurate to within 0.5 % between the attenuator range steps. 5.4 Sample Inlet System: 5.4.1 The sample inlet system must be constructed of materials that are inert and nonadsorptive with respect to the components in the sample. The preferred material of construction is stainless steel. Copper and copper-bearing alloys are unacceptable. 5.4.2 Provision must be made to introduce into the carder gas ahead of the analyzing column a gas-phase sample that has been entrapped in either a fixed volume loop or tubular section. The injected volume must be reproducible such that successive runs of the same sample agree within the limits of repeatability for the concentration range as specified in 11.1.1. 5.4.3 If the instrument is calibrated with pure components, the inlet system shall be equipped to introduce a sample at less than atmospheric pressure. The pressuresensing device must be accurate to O.1 kPa (1 mm Hg). 5.5 Column Temperature Control: 5.5.1 Isothermal--When isothermal operation is utilized, the analytical columns shall be maintained at a temperature constant to 0.3"C during the course of the sample run and the corresponding reference run. 5.5.2 Temperature Programming--Temperature programming may be used, as feasible. The oven temperature shall not exceed the recommended temperature limit for the materials in the column. 5.6 Detector Temperature Control--The detector temperature shall be maintained at a temperature constant to 0.3"C

(@)

D 1946

during the course of the sample run and the corresponding reference run. The detector temperature shall be equal to, or greater than, the maximum column temperature. 5.7 Carrier Gas--The instrument shall be equipped with suitable facilities to provide flow of carder gas through the analyzer and detector at a flow rate that is constant to 1% throughout the analysis of the sample and the reference standard. The purity of the carrier gas may be improved by flowing the carrier gas through selective filters prior to its entry into the chromatograph. 5.8 Columns: 5.8. l The columns shall be constructed of materials that are inert and nonadsorptive with respect to the components in the sample. The preferred material of construction is stainless steel. Copper and copper-bearing alloys are unacceptable. 5.8.2 Either an adsorption-type column or a partitiontype column, or both, may be used to make the analysis. NOTE I--See Practice E 260 for general gas chromatographyprocedures. 5.8.2.1 Adsorption Column--This column must completely separate hydrogen, oxygen, nitrogen, methane, and carbon monoxide. If a recorder is used, the recorder pen must return to the baseline between each successive peak. Equivalent proof of separation is required for displays other than by chart recorder. Figure 1 is an example chromatogram obtained with an adsorption column. (1) Because of similarities in thermal conductivities, helium should not be used as the carder gas for hydrogen when hydrogen is less than 1% of the sample. Either argon or

nitrogen carrier gas is suitable for both percent and parts per million quantities of hydrogen. (2) The use of a carder gas mixture of 8.5 % hydrogen and 91.5 % helium will avoid the problem of reversing polarities of hydrogen responses as the concentration of hydrogen in the sample is increased. (3) The precision of measurement of hydrogen can be increased by using a separate injection for hydrogen, using either argon or nitrogen for the carrier gas. (4) Another technique for isolating the hydrogen in a sample is to use a palladium transfer tube at the end of the adsorption column; this will permit only hydrogen to be transferred to a stream of argon or nitrogen carder gas for analysis in a second thermal conductivity detector. 5.8.2.2 Partition Column--This column must separate ethane, carbon dioxide, and ethylene. If a recorder is used, the recorder pen must return to the baseline between each successive peak. Equivalent proof of separation is required for displays other than by chart recorder. Figure 2 is an example chromatogram obtained with a partition column.~ 5.8.3 General--Those column materials, operated either isothermally or with temperature programming, or both, may be utilized if they provide satisfactory separation of components. 6. Reference Standards 6.1 Moisture-free mixtures of known composition are required for comparison with the test sample. They must contain known percentages of the components, except oxygen (Note 2), that are to be determined in the unknown sample. All components in the reference standard must be

u.I x 0

z i=J

z 0 :E

0

Oc

F-

Z o m re"

Z w >x 0

0

A I

I

I

I

I

I

IO

9

8

7

6

5

I 4

Z W 0 0 n., ¢3 >,.r

I

I

I

3

2

I

MINUTES Column: 2 m by 6 mm inside diameter Type 13x molecular sieves, 14 to 30 mesh Temperature: 35=C

FIG. 1

Flow rate: 60 mL helium/rain Sample size: 0.5 mL

Chromatogram of Reformed Gas on Molecular Sieve Column

303

~

D 1946 ¢J

X o

,,,4 "t=

,,4

.<

O

,.o =r o

.x: /,J

O ¢J

0

I

2

3

4

Minutes Column: 1.2 m by 6.35 mm Porapak Q, 50 to 80 mesh Current setting: 225 mA

FIG. 2

Temperature: 40"C Flow rate: 50 mL heUum/min Sample size: 0.5 mL

Chromatogram of Reformed Gas on Porapak Q Column

fraction of oxygen plus argon. Argon elutes with oxygen in the molecular sieves column. Do not rely on oxygen standards that have been prepared for more than a few days. It is permissible to use a response factor for oxygen that is relative to a stable component.

homogeneous in the v a p o r state at the time o f use. The fraction o f a c o m p o n e n t in the reference standard should not be less than one half of, n o r differ by m o r e than l0 mol % from, the fraction o f the corresponding c o m p o n e n t in the unknown. The c o m p o s i t i o n o f the reference standard m u s t be known to within 0.01 tool % for any c o m p o n e n t .

7. Preparation of A p p a r a t u s

7.1 Column Preparation--Pack a 2 to 3-m c o l u m n (6-mm inside diameter stainless steel tubing) with Type 13x molecular sieves, 14 to 30 mesh, that have been dried 12 h or more at 300 to 350"C. Pack a second c o l u m n (1 m by 6 ram) with Porapak Q,3 50 to 80 mesh, that has been dried 12 h or more at about 150"C. Shape the c o l u m n s to fit the configuration o f the oven in the c h r o m a t o g r a p h .

NOTE 2--Unless the reference standard is stored in a container that has been tested and proved for inertness to oxygen, it is preferable to calibrate for oxygen by an alternative method. 6.2 Preparation--A reference standard m a y be prepared by blending pure c o m p o n e n t s . Diluted dry air is a suitable standard for oxygen a n d nitrogen.

NOTE 4--Variations in column material, dimensions, and mesh sizes of packing are permissible if the columns produce separations equivalent to those shown in Figs. I and 2. Better performance may be obtained by

NOTE 3--A mixture containing approximately 1% of oxygen can be prepared by pressurizing a container of dry air at atmospheric pressure to 20 atm (2.03 MPa) with pure helium. This pressure need not be measured precisely, as the fraction of nitrogen in the mixture such prepared must be determined by comparison to nitrogen in the reference standard. The fraction of nitrogen is multiplied by 0.280 to obtain the

3 Availablefrom WatersAssociates,Inc., Framingham,MA 01701. 304

t~) O 1946 using a 2. I-mm stainless steel tubing with corresponding smaller mesh packing materials and substituting Haysep Q for Porapak Q.

certified value of that component in the calibration standard. 9.2 Manual Measurement--Measure the response of each component, convert to the same sensitivity for corresponding components in the sample and reference standard, and calculate the mole percent of each component in the sample as follows: C = (A/B)(S) where: C = mole percent of the component in the sample, A = response of the component in the sample, B = response of the component in the standard at the same sensitivity as with A, and S = mole percent of the component in the reference standard. 9.3 If a helium-diluted air mixture was run for oxygen calibration, calculate the fraction of oxygen in the mixture from the fraction of the nitrogen and the composition of the diluted air. Calculate the fraction of nitrogen in the mixture in accordance with 9.1, using the nitrogen response of the reference standard for comparison. Air composition values of 78.1% nitrogen and 21.9 % oxygen should be used, as argon (0.9 % in air) elutes with oxygen on the molecular sieves column. 9.4 If air has been analyzed at reduced pressure to calibrate for oxygen, correct the equation for pressure as follows:

7.2 Chromatograph--Place the proper column and sample volume in operation for the desired run in accordance with 8.1 and 8.2. For isothermal operation, the column should be maintained at a temperature between 30 and 45"C. When appropriate, column temperatures may be increased. Adjust the operating conditions and allow the instrument to stabilize. Check the stability by making repeat runs on the reference standard to obtain reproducible peak heights as described in 5.4.2 for corresponding components. 8. Procedure 8.1 Sample VolumemThe sample introduced into the chromatographic column should have a volume between 0.2 and 0.5 mL. Sufficient accuracy can be obtained for the determination of all but the very minor components with this sample size. When increased sensitivity is required for the determination of components present in low concentrations, a sample size of up to 5 mL is permissible. However, components whose concentrations are in excess of 5 % should not be analyzed by using sample volumes greater than 0.5 mL. 8.2 Chromatograms: 8.2. ! Adsorption Column (Fig. l)--Obtain a steady base line on the recorder with a constant carrier gas flowrate appropriate to the column diameter. Introduce a sample of the unknown mixture at atmospheric pressure into the chromatograph and obtain a response similar to that of Fig. 1 of the components hydrogen, oxygen, nitrogen, methane, and carbon monoxide, which elute in that order. Repeat with a sample of the reference standard. If oxygen is present in the mixture, run a sample of air, either at an accurately measured reduced pressure, or air freshly diluted with helium, so that the partial pressure of oxygen is approximately equal to that of the oxygen in the mixture being analyzed.

C = (A/B)(S)(PJPb)

where: Pa = absolute pressure at which air was analyzed, and Pb - barometric pressure when sample was analyzed, with both pressures being expressed in the same units. 9.5 Normalize the mole percent values by multiplying each value by 100 and dividing by the sum of the original values. The sum of the original values should not differ from 100.0 % by more than 1.0 %. 10. Analysis of the Reference Standard 10.1 If the composition of the reference standard is not known to a sufficient degree of accuracy, analyze it by the use of pure components for calibration. Obtain chromatograms of the standard as described in 8.2, except measure the pressure of each sample introduced to 0.133 kPa (1 mm Hg). When each chromatogram is obtained, calibrate each component by introducing a sample of the pure component at a pressure that closely approximates its partial pressure in the blend (for example, a component whose concentration in the standard is 50 % is analyzed at 50 % of the pressure at which the standard was analyzed). Use a minimum pressure of 0.665 kPa (5 mm Hg) for minor components. Repeat the analysis with the reference standard. Corresponding peak heights should agree within 1 mm or 1% (whichever is larger) when recorded on a sensitivity setting that allows maximum response on the recorder chart. 10.2 Calculate the composition of the reference standard by the adjustment of responses of like components to the same sensitivity, and calculate the concentration of each component as follows:

Nor~ 5--The peak for carbon monoxide can appear between those

of nitrogen and methaneif the molecularsieveshave become contaminated. If this occurs, replace or regenerate the column packing by heating in accordancewith 7.1. 8.2.2 Partition Column (Fig. 2)--Establish a steady base line with the helium carrier gas flowing through the Porapak Q column. Introduce a sample of the reference standard, and then a sample of the unknown mixture. Obtain responses similar to that shown in Fig. 2 for carbon dioxide, ethane, and ethylene. 8.2.3 All chromatograms for manual measurement should be run at a sensitivity setting that permits maximum peak height to be recorded for each component. 8.2.4 Column isolation valves may be used to make the entire analysis with a single injection if the separations specified in 5.8.2.1 and 5.8.2.2 are produced. 9. Calculation 9.1 The number of significant digits retained for the quantitative value of each component shall be such that accuracy is neither sacrificed nor exaggerated. The expressed numerical value of any component in the sample should not be presumed to be more accurate than the corresponding

C = (IO0)(R)(Pp) (P)(Pr)

305

(~) D 1946 where: C = component concentration, mole percent, R = response of the component in the reference standard, P = response of the pure component, Pp = pressure at Which the pure component was analyzed, and Pr = pressure at which the reference standard was analyzed, with both pressures being expressed in the same absolute units. 10.2.1 Normalize all values as described in 9.4.

Component, mot %

Repeatability

0 to I I to5 5 to 25 Over 25

0.05 0.1 0.3 0.5

11.1.2 ReproducibilitymResults submitted by different laboratories should not differ by more than the amounts given in 11.1.1 when the same reference standard is used for calibration and the same composition is used for calculations. If calibration is made with pure components or with different reference standards, results submitted by each of two laboratories should not be considered suspect unless the results differ by more than the following amounts:

11. Precision 11.1 The following data should be used to judge the acceptability of the results: I I. 1. ! Repeatability--Duplicate results by the same operator should not be considered suspect unless they differ by more than the following amounts:

Component, mol %

Reproducibility

0to I I to 5 5 to 25 Over 25

0.1 0.2 0.5 1.0

12. Keywords

12.1 gaseous fuels

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reepproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race SL, Philadelphia, PA 19103.

306

( ~ l ~ Designation: D 1988-91 (Reapproved 1995)H Standard Test Method for Mercaptans in Natural Gas Using Length-of-Stain Detector Tubes 1 This standard is issued under the fixed designation D 1988; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (~) indicates an editorial change since the last revision or reapproval.

e~NOTE--Section9 was addededitoriallyin June 1995. 1. S c o p e 1.1 This test method covers a rapid and simple field determination of mercaptans in natural gas pipelines. Available detector tubes provide a total measuring range of 0.5 to 160 ppm by volume of mercaptans although the majority of applications will be on the lower end of this range (that is, under 20 ppm). Besides total mercaptans, detector tubes are also available for methyl mercaptan (0.5 to 100 ppm), ethyl mercaptan (0.5 to 120 ppm), and butyl mercaptan (0.5 to 30 mg/M 3 or 0.1 to 8 ppm). NOTE l--Certain detector tubes are calibrated in terms of milligrams per cubic metre (mg/M3) instead of parts per million by volume. The conversion is as followsfor 25"C (77"1=)and 760 mm Hg. ppm x molecular weight mg/M 3 = 24.45 1.2 Detector tubes are usually subject to interferences from gases and vapors other than the target substance. Such interferences may vary among brands due to the use of different detection principles. Many detector tubes will have a precleanse layer designed to remove interferences up to some maximum level. Consult manufacturer's instructions for specific interference information. Hydrogen sulfide and other mercaptans are usually interferences on mercaptan detector tubes. See Section 5 for interferences of various methods of detection. 1.3 This standard does not purport to address all of the

with a specially prepared chemical. Any mercaptan present in the sample reacts with the chemical to produce a color change, or stain. The length of the stain produced in the detector tube, when exposed to a measured volume of sample, is directly proportional to the amount of mercaptan present in the sample. A hand-operated piston or bellowstype pump is used to draw a measured volume of sample through the tube at a controlled rate of flow. The length of stain produced is converted to parts per million (ppm) by volume mercaptan by comparison to a calibration scale supplied by the manufacturer for each box of detection tubes. The system is direct reading, easily portable, and completely suited to making rapid spot checks for mercaptans under field conditions (see Note 1). 4. S i g n i f i c a n c e and U s e

4.1 The measurement of mercaptans in natural gas is important, because mercaptans are often added as odorants to natural gas to provide a warning property. The odor provided by the mercaptan serves to warn consumers (for example, residential use) of natural gas leaks at levels that are well below the flammable or suffocating concentration levels of natural gas in air. Field determinations of mercaptans in natural gas are important due to the tendency of the mercaptan concentration to fade over time. 4.2 This test method provides inexpensive field screening of mercaptans. The system design is such that it may be used by nontechnical personnel, with a minimum of proper training.

safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements, see Note 5.

5. I n t e r f e r e n c e s

5.1 Interference from hydrogen sulfide gas (H2S) is a common problem with mercaptan detector tubes and its extent should be understood in order to make use of tube readings. There are at least three detection principles used in mercaptan detector tubes and each is summarized below. 5.1.1 Palladium sulfate is used by at least one manufacturer. It has a positive interference from H2S but H2S may be removed in a preconditioning layer at the front of the tube. If this is the case the manufacturer will state some finite level of H2S where interference initiates (for example, greater than 500 ppm H2S causes a positive error). Consult manufacturers' instruction sheets for this information. Propylene and hydrocarbons of five or more carbon atoms will cause interfering discolorations making the palladium sulfate detection principle ineffective for liquefied petroleum gas (LPG). (Palladium chloride is used by at least one manufac-

2. R e f e r e n c e d D o c u m e n t s

2. l Gas Processors Association Standard." 2 GPA Standard 2188 Tentative Method for the Determination of Ethyl Mercaptan in LP Gas Using Lengthof-Stain Detector Tubes, Appendix B, Test for Ethyl Mercaptan Odourant in Propane, Field Method, 1988. 3. S u m m a r y o f T e s t M e t h o d

3.1 The sample is passed through a detector tube filled J This test method is under the jurisdiction of ASTM Committee 1)-3 on Gaseous Fuels and is the direct responsibility of Subcommittee I)03.05 on Determination of Special Constituents of Gaseous Fuels. Current edition approved March 15, 1991.PublishedMay 199I. 2AvailablefromGas ProcessorsAssn.,6526East60th, Tulsa,OK 74145. 307

o 19aa NOTE 3--A suitable sampling chamber may be devised from a polyethylene wash bottle of nominal 500-mL or l-L size. The wash

turer and it exhibits similar H2S interference as with the palladium sulfate detection principle. Palladium chloride may also exhibit the hydrocarbon interference described for the palladium sulfate detection principle. Contact the manufacturer for specific interference information.) 5.1.2 Mercuric chloride is used by at least one manufacturer. It has a positive interference from H2S but does not have the hydrocarbon interference described above for palladium sulfate. This detection principle is preferred for LPG applications. H2S will produce a stain on mercuric chloride tubes even if mercaptans are not present. The approximate H2S sensitivity ratio is as follows: One part per million H2S will produce a reading of 0.4 to 0,7 p p m mercaptans. Consult manufacturers for exact information if it does not appear in tube instruction sheets. 5.1.3 A two-stage copper salt/sulfur reaction is used by at least one manufacturer. This detection principle has a positive interference from H2S with H2S being twice as sensitive (that is, l0 ppm H2S will appear as 20 p p m mercaptan). Ammonia or amines also interfere with this principle producing a second color.

bottle's internal delivery tube provides for delivery of sample gas to the bottom of the bottle. A I/2-in. (13-mm) hole cut in the bottle's cap provides access for the detector tube and vent for the purge gas (see Fig. l). Purge gas must be vented at a sufficient rate so that pressure does not build up within the sampling chamber and increase the flow rate through the detector tube. (An alternative flow-through sampler may be fashioned using a l-gal zipper-type food storage bag. The flexible line enters one comer ofthe bag's open end and extends to the bottom of the bag. The opposite corner of the open end is used for tube access and sample vent. The remainder of the bag's top is sealed shut. The basic procedure for the sampler in Fig. l applies.) NOTE 4--An alternative sampling container is a collection bag made of a material suitable for the collection of natural gas (for example, polyester film). The sampling bag should have a minimum capacity of 2 L. 7. Procedure 7.1 Select a sampling point that will provide access to a representative sample of the gas to be tested (source valve on the main line). The sample point should be on top of the pipeline and equipped with a stainless steel sample probe extending into the middle third of the pipeline. Open the source valve momentarily to clear the valve and connecting nipple of foreign materials. 7.2 Install needle valve (or pressure regulator) at the source valve outlet. Connect sampling chamber using the shortest length of flexible tubing possible (see Fig. 1). Avoid using tubing which reacts with or absorbs mercaptans, such as copper or natural rubber. Use materials such as TFEfluorocarbon, vinyl, polyethylene, or stainless steel. 7.3 Open source valve. Open needle valve enough to obtain positive flow of gas through the chamber, in accordance with 6.3. Purge the container for at least 3 min (see Fig. 1).

6. Apparatus 6.1 Length-of-Stain Detector Tube--A sealed glass tube with breakoff tips sized to fit the tube holder of the pump. The reagent layer inside the tube, typically a silica gel substrate coated with the active chemicals, must be specific to mercaptans, and produce a distinct color change when exposed to a sample of gas containing mercaptans. Any substances known to interfere must be listed in the instructions accompanying the tubes. A calibration scale printed on the glass tube shall correlate mercaptan concentration to the length oftbe color stain. A separate calibration scale supplied with the tubes shall be acceptable. Shelf life of the detector tubes must be a minimum of two years from date of manufacturer, when stored according to manufacturer's recommendations. 6.2 Detector Tube PumpmA hand-operated p u m p of a piston or bellows type. It must be capable of drawing 100 m L per stroke of sample through the detector tube with a volume tolerance of +5 mL. 3 It must be specifically designed for use with detector tubes. NOTE 2 - - A detector tube and pump together form a unit and must

be used as such. Each manufacturer calibrates detector tubes to match the flow characteristicsof their specific pump. Crossingbrands of pumps and tubes is not permitted, as considerable loss of system accuracy is likely to occur)

LTAB'E'LE: B'E

6.3 Gas Sampling ChambermAny container that provides for access of the detector tube into a uniform flow of sample gas at atmospheric pressure, and isolates the sample from the surrounding atmosphere. A stainless-steel needle valve (or pressure regulator) is placed between the source valve and the sampling chamber for the purpose of throttling the sample flow. Flow rate should approximate one to two volume changes per minute, or, at minimum, provide a positive exit gas flow throughout the detector tube sampling period.

[J

f

PUMP

~TUBE ~ & GASACCESS VENT GASS A M P L I N G ~ CHAMBER

3 Direct Reading Colorimetrw Indicator Tubes Manual, American Industrial

FIG. 1

Hygmne Association, Akron, OH, 1976.

308

ApparatusSchematic

DETECTOR TUBE

o 19a8 NOTE 5: Precaution--Take precautions to vent the gas away from persons collecting the sample such that the exposure to the gas is minimal. Escaping gases will produce flammable mixtures in air. Keep sources of heat, spark, or flame away from the sampler. NOTE 6--If a collection bag is used instead of a sampling chamber, follow 7.1 and 7.2, substituting the bag for the chamber. Follow 7.3, disconnecting the bag when filled. Deflate the bag to provide a purge, and fill a second time to provide a sample. The bag must be flattened completely prior to each filling (Note 4).

NOTE 10--If the calibration scale is not printed directly on the detector tube, be sure that any separate calibration chart is the proper match for the tube in use. 7.9 If the number of strokes used differs from the number of strokes specified for the calibration scale, correct the reading, as follows: A = (B x C / D )

(1)

where: A = ppm (corrected), B = ppm (reading), C = specified strokes, and D = actual strokes. 7. l0 Record the reading immediately, along with the gas temperature and the barometric pressure. Observe any temperature corrections supplied in the tube instruction. Altitude corrections become significant at elevations above 2000 ft. Correct for barometric pressure, as follows:

7.4 Before each series of measurements, test the p u m p for leaks by operating it with an unbroken tube in place. Consult manufacturer's instructions for leak check procedure details and for maintenance instruction, if leaks are detected. The leak check typically takes 1 min. A leaking p u m p used in field testing will bias sample results low. 7.5 Select the tube range that best encompasses mercaptan concentration. Reading accuracy is improved when the stain length extends into the upper half of the calibration scale. Consult manufacturer guidelines for using multiple strokes to achieve a lower range on a given tube. 7.6 Break off the tube tips and insert the tube into the pump, observing the flow direction indication on the tube. Place the detector tube into the sampling chamber through the access hole, such that the tube inlet is near the chamber center (see Fig. 1).

a = (B × E / F )

(2)

where: E = barometric pressure, 760 m m Hg, and F = ambient barometric pressure, m m Hg. NOTE l l--Even though the amount of chemicals contained in detector tubes is very small, the tubes should not be disposed of carelessly. A general disposal method includes soaking the opened tubes in water prior to tube disposal. The water should be pH neutralized prior to its disposal. Observe all local, state, and federal regulations for small scale chemical disposal.

NOTE 7--Detector tubes have temperature limits from 0 to 40"C (32 to 104*F), and sample gases must remain in that range throughout the test. Cooling probes are available for sample temperatures exceeding 40"C.

8. Precision and Bias 8.1 The accuracy of detector tube systems is generally considered to be _+25 % of reading. This is based mainly on programs conducted by the National Institute of Occupational Safety and Health (NIOSH) in certifying detector tubes for low level contaminants in air, adapted to worker exposure monitoring: NIOSH tested tubes at 1/2, l, 2, and 5 times the threshold limit value (TLV), requiring _+25 % accuracy at the three higher levels, and +35 % at the 1/2 TLV level. (For example, H2S with a TLV of 10 p p m was tested at levels of 5, 10, 20, and 50 ppm.) The higher tolerance allowed at the low level was due to the loss of accuracy for shorter stain lengths) NIOSH discontinued this program in 1983, and it was picked up by the Safety Equipment Institute (SEI) in 1986. 8.2 The Gas Processors Association reported a precision of + 15 % for determination of ethyl mercaptan in propane using detector tubes (see GPA 2188).

7.7 Operate the p u m p to draw the measured sample volume through the detector tube. Observe tube instructions when applying multiple strokes. Ensure that a positive flow is maintained throughout the sample duration at the sampling chamber gas exit vent. Observe tube instructions for proper sampling time per p u m p stroke. The tube inlet must remain in position inside the sampling chamber until the sample is completed. Many detector tube pumps will have stroke finish indicators that eliminate the need to time the sample. NOTE 8 - - I f a collection bag is used, the sample is drawn from the bag by way of a flexible tubing connection. Do not squeeze the bag during sampling. Allow the bag to collapse under pump vacuum, so that the pump's flow characteristics are not altered. NOTE 9: Caution--It is very important to ensure that ambient air is not being drawn into the sample. Intrusion of ambient air into the sample will tend to bias the mercaptan readings low.

7.8 Remove the tube from the p u m p and immediately read the mercaptan concentration from the tube's calibration scale, or from the charts provided in the box of tubes. Read the tube at the m a x i m u m point of the stain. If channeling has occurred (nonuniform stain length), read the m a x i m u m and minimum stain lengths and average the two.

9. Keywords 9.1 gaseous fuels; natural gas 4 "NIOSHCertificationRequirementsfor Gas DetectorTube Units," NIOSH/ TC/A-OI2, National Instituteof OccupationalSafetyand Health, July 1978.

309

t~ D 1988 The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103.

310

~1~

D e s i g n a t i o n : D 2 0 0 7 - 93

An Amencan National Standard

Standard Test Method for Characteristic Groups in Rubber Extender and Processing Oils and Other Petroleum-Derived Oils by the Clay-Gel Absorption Chromatographic Method 1 This standard is issued under the fixed designation D 2007; the number immediately following the designation indicates the year of original adoption or, m the case of revision, the year of last revision, A number in parentheses indicates the year of last reapproval, A superscript epsdon (0 indicates an editorial change since the last revision or reapproval.

3. Terminology

1. Scope 1.1 This test method covers a procedure for classifying oil samples of initial boiling point of at least 260"C (500*F) into the hydrocarbon types of polar compounds, aromatics and saturates, and recovery of representative fractions of these types. This classification is used for specification purposes in rubber extender and processing oils.

3.1 Descriptions of Terms Specific to This Standard: 3.1.1 The following terms refer to the hydrocarbon types and structural groups as measured by this test method: 3.1.1.1 asphaltenes, or n-pentane insolublesDinsoluble matter that precipitates from a solution of oil in n-pentane under the specified conditions. 3.1.1.2 polar compoundsmmaterial retained on adsorbent clay after percolation of the sample in n-pentane eluent under the conditions specified. 3.1.1.3 polar a romatics--synonym for polar compounds. 3.1.1.4 aromatics--material that, on percolation, passes through a column of adsorbent clay in a n-pentane eluent but adsorbs on silica gel under the conditions specified. 3.1.1.5 saturatesDmaterial that, on percolation in a n-pentane eluent, is not adsorbed on either the clay or silica gel under the conditions specified.

NOTE l - - S e e Test Method D 2226,

1.2 This test method is not directly applicable to oils of greater than 0.1 mass % pentane insolubles. Such oils can be analyzed after removal of these materials, but precision is degraded (See Appendix X l). 1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. 1.4 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Specific precaution statements are given in Notes 2, 3, 4, 5, AI.1, and AI.2.

4. Summary of Test Method 4.1 The sample is diluted with solvent and charged to a glass percolation column containing clay in the upper section and silica gel plus clay in the lower section, n-Pentane is then charged to the double column until a definite quantity of effluent has been collected. The upper (clay) section is removed from the lower section and washed further with n-pentane. A toluene-acetone mixture 50 to 50 by volume is then charged to the clay section for desorption and a specified volume of effluent collected. The lower (gel) column may be desorbed by recirculation of toluene. 4.2 The solvents are completely removed from the recovered n-pentane and the toluene-acetone fractions and the residues are weighed and calculated as saturate and polar compounds contents. Aromatics may be calculated by difference, or measured following evaporation of the toluene used for desorption of the gel column. 4.3 When the sample contains more than 0.1 mass % of n-pentane insolubles, this test method cannot be used directly. The insoluble matter must be removed from the sample prior to charging to the column. A method for this removal is given as an appendix. 4.4 Alternative methods are provided (a) for recovery of aromatics from the gel column, and (b) for analysis of oil with high-polar content.

2. Referenced Documents 2.1 ASTM Standards: D 86 Test Method for Distillation of Petroleum Products2 D323 Test Method for Vapor Pressure of Petroleum Products (Reid Method)2 D 329 Specification for Acetone3 D 841 Specification for Nitration Grade Toluene 3 D 1159 Test Method for Bromine Number of Petroleum Distillates and Commercial Aliphatic Olefins by Electrometric Titration2 D 2226 Classification for Various Types of Petroleum Oils for Rubber Compounding Use4 D 3055 Specification for Cyclohexane 9953 E 691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method5 This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee I)02.04 on Hydrocarbon Analysis. Current edition approved Feb. 15, 1993. Published May 1993. Originally published as D 2007 - 68T. Last previous edition D 2007 - 91. 2 Annual Book of ASTM Standards, Vol 05.01. 3 Annual 11ook of ASTM Standards, Vol 06.04, 4 Annual Book of ASTM Standards, Vol 09.01. s Annual Book of ASTM Standards, Vol 14.02.

5. Significance and Use 5.1 The composition of the oil included in rubber compounds has a large effect on the characteristics and uses of the compounds. The determination of the saturates, aro311

iI~

GLASS WOOL

D 2007

l

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/

/

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I

II "-'

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MAOe FRO. rrANOARO ~ CHROMATOGRAPHICTUBE J 44,~600: CONNING

-I II. J .YI ~ I

NoTE--Check to ascertainID is 44 ram. FIG. 1

Clay-Gel Percolating Column

6.10 Adapter Tube with Vigreux column (Fig. 2).8 6.11 Flexible Joint, TFE-fluorocarbon and borosilicate, 24/40 T s ground glass joints on each end?

matics, and polar compounds is a key analysis of this composition. 5.2 The determination of the saturates, aromatics, and polar compounds and further analysis of the fractions produced is often used as a research method to aid understanding of oil effects in rubber and other uses. 6. Apparatus 6.1 Beakers, Anticreep,6 150-mL capacity. 6.2 Clay-Gel Column, constructed as illustrated in Fig. I. 6.3 Conical Flasks, (Erlenmeyer), 250-mL capacity. 6.4 Conical Flasks, (Erlenmeyer), wide-mouth, graduated, 500-mL capacity. 6.5 Filter Funnel, long stem, 125-ram diameter; for use with 185 mm ready folded, fine-texture, rapid filter paper. 6.6 Separatory Funnel, 500 mL. 6.7 Hot Plate, explosion proof, controlled to a surface temperature of 100 to 1 0 5 ° C . 7 6.8 Round Bottom Flask, 3-necked, borosilicate, 500-mL capacity (Fig. 2). 6.9 Condenser, borosilicate (Fig. 2).

7. Reagents and Materials 7.1 Acetone, conforming to Specification D 329. (Warning--See Note 2.) NOTE 2: Warning--Acetone is extremely flammable. 7.2 Calcium Chloride, anhydrous granules. 7.3 Clay Adsorbent, 500 to 250 pm (30 to 60 mesh) Attapulgus) ° Clay quality may be determined using the azobenzene equivalence test shown in Annex A I. The azobenzene activity test measures the adsorptive characteristics of the clay. Azobenzene equivalence value should be 30 to 35. Clay outside of these limits should be discarded. 7.4 Cyclohexane, conforming to Specification D 3055. (Optional, see 8.2.) (Warning--See Note 3.) s This item can be fabricated at any scientific glassblowing shop. It is also available from Owens Glass Apparatus, Inc., 128 River Road, Channelview, TX 77530. 9 Cole Parmer No. 6675-40 has been found suitable for this purpose. io Available from Forcoven Products, P.O. Box 1556, Humble, TX 773471556. Packaged in moisture resistant twinned packets of 50 and 100 g (sufficient for one determination). These packets are packed 50 sets per case. It is important that extremes of temperature be avoided on stored clay samples.

6 Available from U.S. Testing Co., No. SIS-7712. For safety purposes, beakers should be examined for sharp edges and fire polished, if necessary. Also available from Owens Glass Apparatus, Inc., 128 River Road, Channelview, TX 77530. 7 Temperatures should be uniform on the top ofthe hot plate. Some laboratory hot plates benefit by the inclusion of an aluminum plate, approximately 6-ram thick, included under or on top of regular plate top.

312

~

D 2007 7.6.1 Gel should be activated for 4 h in an air oven at 190°C in a shallow pan. 7.7 Toluene, conforming to Specification D 841. (Warning--See Note 5.)

Refl/~.Condensar 24

NOTE 5: Warning--Tolueneis flammable.Vapor harmful. 7.8 Toluene-Acetone Mixture (50 to 50 by volume), mix equal volumes of toluene and acetone. 7.9 In order to obtain results that are consistent with those obtained elsewhere, it is very important that only the reagents and materials described in this section be used.

Val veA(Stopco Open to take off Solvent

8. Procedure 8.1 Fractionation: 8.1.1 Prepare the adsorption column (Fig. 1) by placing 100 g of clay adsorbent in the upper section of the column and 200 g of silica gel plus 50 g of clay on top of the gel in the lower section (Note 4). Place a piece of glass wool (of about 25-mm loose thickness) over the top surface of the clay in the upper column to prevent agitation of the clay while charging the eluent solvents. Join the columns (clay over gel) after lubricating the joint with hydrocarbon-insoluble grease. It is important that the adsorbents in each column be packed to a constant level. A minimum of ten taps with a soft rubber hammer at different points up and down and 25 taps on top of each column should be employed to achieve constant level. A suitable rubber hammer may be assembled by fastening two No. 7 or 8 rubber stoppers on one end of a small rod about 200-mm long. Use fresh adsorbents for each determination. 8.1.2 If n-pentane insolubles were not determined, select the appropriate sample size in accordance with the following polar content ranges, if the proper range can be anticipated; otherwise, use a 10 :t: 0.5 g sample.

Waste Solvent Receiver

Column

f~m Separation

k

4/40

antic

FIG.2

Extraction Apparatus

NOTE 3: Warning--Cyclohexaneis extremelyflammable.Harmfulif inhaled. 7.5 n-Pentane, ~' conforming to the following requirements: (Warning--See Note 4.) NOTE 4: Warning--n-Pentane is extremelyflammable. Harmful if inhaled. Distillation (Test Method D 86). Initial boiling point, min Dry point, max

33.4"C (92"F) 40.5'C (105"F)

Reid vapor pressure (Test Method D 323), max 110 kPa (17 psi); Bromine number (Test Method D 1159), 0.5 maximum; Isopentane, maximum, 10 %; n-pentane, minimum, 80 %. 7.6 Silica Gel, activated, conforming to the following inspections:' 2 Sieve analysis > 30 sieve size, > 50 sieve size, >100 sieve size, >200 sieve size,

Polar Content Range, mass percent

Sample Size, g

0-20 Above 20

10 ± 0.5 5 ± 0.2

8.1.3 Dilute with 25 mL of n-pentane solvent and mix well to ensure a uniform solution of the sample. The sample should not display precipitate or flocculate at this point. If a precipitate is present, "asphaltenes" may be removed by the procedure of Appendix X.I, however, the precision statement no longer applies. It is important that the polar content result obtained be not greater than that for the sample size as specified above, since the capacity of the clay for retaining polar constituents becomes limited at these concentrations. If results exceed this specification, repeat the test using a smaller sample. Partitioning between aromatics and polar compounds is affected by sample size. Results using different sample size may not be equivalent. NOTE 6--For viscous oils, dilutions of the sample with 25 mL of cyclohexane is more convenient and does not affect the results. Cyclohexane used in this manner will not detect small quantities of asphaltenes, however.

5 % (mass) maximum; 45 % (mass) rain 80 % (mass) min 94 % (mass) rain

I DAvailable from Special Products Div., Phillips Petroleum Co., Bartlesville, OK. 12 Gel meeting these specificationsis availablefrom Forcoven Products, P.O. Box 1556, Humble, T X 77347-I 556, packaged in 200 g moisture resistantpackets. Sieve analysisshould be checked on other sources of gel.

313

8.1.4 Add 25 mL of n-pentane to the top of the clay portion of the assembled column and allow to percolate into the clay. As soon as nearly all of the n-pentane has entered the clay, charge to the column the diluted sample of 8.1.2. Wash the sample beaker (or flask) with n-pentane and add

~

D 2007 isolation rather than by difference, the gel column (lower column of the clay gel adsorption column of 8. I. 1, Fig. 1), after the 280 + 10 mL of n-pentane have been collected, is placed in the extraction assembly of Fig. 2. 8.2.2 Toluene (200 4- 10 mL) is placed in the 500-mL flask and refluxed at such a rate of l0 4- 2 mL/min for 2 h. NOTE 10--Toluene reflux can be measured by collection for a I rain period using a graduated cylinder through valve A, Fig. 2.

the washings to the column. After nearly all of this material has entered the clay, wash the walls of the column above the clay free of sample with n-pentane. The sample and eluent solvent can be added to the column through a 65-mm diameter, wide-stem funnel (the funnel can be left on top of the column). At no time during the run should air be allowed to enter the clay bed. 8.1.5 When nearly all of the washings have entered the clay, charge n-pentane to the column and maintain a head level well above the clay beds (Note 7) to wash the saturate portion of the sample from the adsorbents. Recover 280 _+ 10 mL of the first n-pentane effluent from the column in a graduated, 500-mL wide-mouth conical flask. NOTE 7--Columns may be briefly separated, if necessary, to give a solvent head 5- to 10-mm deep in the second (lower) column. Loss of the head will give channeling in the lower column, with inaccurate results. NOTE 8--With long use, the flits in the absorption columns become progressively less porous. If the time for percolation doubles over that for a new column, the slow columns are to be discarded.

8.2.3 At the end of this time, the valve (A) is opened and the toluene removed into a waste solvent receiver to a volume of approximately 50-mL in the flask. The solution remaining is then combined with the n-pentane from 6.5 for recovery of aromatics. Do not go further by distillation, as oil will be lost, giving inaccurate results. 8.3 Solvent Removal: 8.3.1 Label and weigh for tare the anti-creep beakers that are to be used for the evaporation of solvent (one each for polar compounds, saturates, and aromatics desorbed). Place them on the controlled hot plate at surface temperature of 100°C to 105"C, fill approximately half full with the respective solutions (saturates from 8.1.5, aromatics from 8.1.6 and 8.2.3, polars from 8.1.9), refilling as this volume is reduced to one-quarter full. A gentle nitrogen sweep may be used over the surface of the liquid. It should not ruffle the surface nor should this nitrogen jet be placed below the surface. The flasks which contained the fractions should be rinsed with n-pentane, and this n-pentane added to the respective anti-creep beakers. 8.3.2 When essentially all the solvent is evaporated, weigh the beakers at 10 min intervals. Solvents are considered removed when the weight loss between weighings is less than 10 rag.

8.1.6 Disconnect the two sections. Allow the lower section to drain into a receiver. Continue washing the upper clay section with n-pentape. Maintain a moderate liquid head level above the clay r' ,ring this wash and adjust n-pentane additions so that the level is about 25 mm when 150 mL have been collected in the receiver. Discontinue additions at this point and allow the liquid to essentially drain from the column. The quantity in the receiver should then be about 200 mL. The n-pentane from this step and from the draining of the lower column should be discarded if aromatics are to be determined by difference. This n-pentane should be added to the aromatics solution from the gel column during solvent evaporation (8.3.1) if aromatics are to be recovered. NOTE 9--This extra n-pentane washing of the clay section is necessary in order to ensure complete removal of aromatics from the clay. 8.1.7 After n-pentane effluent has essentially drained from the column, charge a 50 to 50 volume mixture of toluene-acetone. Collect the effluent in a 500-mL separatory funnel. Collect 250 mL of the toluene-acetone (plus n-pentane) effluent or until the effluent is practically colorless (only in exceptional cases will more than 300 mL of effluent be required). 8.1.8 Stopper the separatory funnel containing the toluene-acetone fraction and swirl it a few times to aid in settling the water. Then let it stand for about 5 min. Drain off and discard the lower (aqueous) layer. Add approximately 10 g of anhydrous calcium chloride granules to the fraction remaining in the separatory funnel and shake for about 30 s; vent frequently during the shaking period. Allow the mixture to settle for at least 10 min. 8.1.9 Filter the fraction through a rapid folded filter paper catching the filtrate in a 500-mL conical flask. Rinse the separatory funnel with approximately 25 mL of n-pentane, filter and collect with the mixed solvent fraction. Wash the filter paper with an additional l 0 to 15 mL of n-pentane and collect with the mixed solvent fraction. I M P O R T A N T m Make all transfers of organic solvents from the separatory funnels through the top and avoid transferring any water that may have accumulated around the calcium chloride. 8.2 Desorption of Aromatics: 8.2.1 If it is desired to determine the aromatics by

9. Calculation 9.1 Calculate the amount of n-pentane insolubles, saturates, aromatics, and polar compounds in the sample as follows: Saturates, mass % = (B/A) x 100 (l) Aromatics, mass % = (C/A) x 100 (2) Polar compounds (Note 1!), for l0 g sample = (D/A) x 100 (3) Polar compounds, mass % for 5 g sample = [(0.88 x D/A)] x 100 (4) where: A = grams of original sample used, B = grams of residue from n-pentane effluent from the clay gel column (8.1.5), C = grams of residue from the toluene desorption of the lower column and from the last n-pentane rinse of the columns (8.1.6 and 8.2.3), and D = grams of residue from toluene-acetone effluent (8.1.9). NOTE 1 l - - T h e factor included in the calculation for the 5 g sample is established experimentallyto maintain continuity of results over a wide range of polar compounds in rubber extender oils. 9.2 The total mass of all the recovered fractions must equal at least 97 % of the sample charged. If this recovery is not obtained, repeat the test. 9.3 If aromatics were not desorbed, use the n-pentane insolubles, saturates content, and polar compounds as determined in 9.1, calculate the amount of aromatics as follows:

314

~) D 2007

3-~

SJ2SllS

~

'~R 1 ~ ml

ESERVOIR

i

MERCURY MANOMETER o REGULATED sou,

~'[ § =..

.

~o

I/ ~20

GRAMS CLAY

t °ROUND O,NT W,TH . O O . "~3~,41---TEFLON STOPCOCKWITH INTERNAL "IT v METERINGNEEDLE VALVE

FIG. 3

Aromatics, mass % = 100 - (E + F).

AzobenzenePercolationAssembly 11.1.1 Repeatability--The difference between two test results, obtained by the same operator with the same apparatus under constant operating conditions on identical test material, would in the long run, in the normal and correct operation of the test method, exceed the following values only in one case in twenty:

(5)

where: E = mass % saturates, and F = mass % polar compounds. 10. Report 10.1 Report the following information: 10. I. 1 Sample identification. 10. 1.2 Saturate content, aromatic content, and polar content in mass %. 10.1.3 Method of determination of aromatic content: desorption (8.2) or difference (9.3). 10.1.4 If aromatics were desorbed, the percent recovery (l 1.3). 10.1.5 Asphaltene content if the method of Appendix X. 1 was used.

Saturate Content, Mass % Aromatic Content, Mass % Polar Content, Mass % at polar contents of less than 1% at polar contents of I to 5 % at polar contents of greater than 5 %

2. I 2.3 0.24 0.8 I !.2

11.1.2 Reproducibility--The difference between two single and independent results obtained by different operators working in different laboratories on identical test matedal would, in the long run, in the normal and correct operation of this test method, exceed the following values only in one case in twenty: Saturate Content, Mass % Aromatic Content, Mass % Polar Content, Mass % at polar contents of less than 1% at polar contents of 1% to 5 % at polar contents of greater than 5 %

11. Precision and Bias la 11.1 The precision of this test method as determined by statistical examination of intedaboratory results is as follows:

4.0 3.3 0.4 1.3 1.8

11.1.3 The above precision statements do not include samples that have been prepared by removal of asphaltenes (Appendix XI). The precision on such samples is poorer

,3 Supporting data is available from ASTM headquarters. Request RR:D021193.

315

(~ D 2007 12. Keywords 12.1 clay-gel absorption; elution chromatography; hydrocarbon type; liquid chromatography; petroleum derived oils; rubber extender oils; rubber processing oils

than the statements above. 11.2 Bias--The procedure for measuring saturates, aromatic, and polar contents has no bias because the values are defined only in terms of this test method.

ANNEX

(Mandatory Information) AI. AZOBENZENE ACTIVITY TEST FOR CLAY A1.5.2 Weigh 20 + 0.001 g of clay sample and pour it into the column. AI.5.3 Pack the clay in the column to a constant level by using an electric vibrator.

AI.1 Scope A I.I.I This test method describes a procedure for measuring the adsorption activity of percolatiod type clays.

A1.2 Summary of Test Method A 1.2.1 A solution of I mass % azobenzene in isooctane is percolated through a weighed amount of clay contained in a specified column. The amount of liquid recovered as percolate at the point where the concentration of azobenzene is 0.5 mass % (50 mass % of the original concentration) is a measure of the adsorption activity of the clay.

NOTE A I.2--A satisfactorily packed column will be achieved by lightly holding the vibrator next to the column and moving it up and clown over the clay height. Perform the "up and down" vibrations at 4 points approximately 90" spacings around the column.

AI.5.4 Add 100-115 mL of azobenzene solution to the column. AI.5.5 Collect percolate in graduated 5 or 10-mL cylinders. Maintain the percolation rate at l mL/min. The rate control shall be approximately established after 3 mL have been collected and well established by the time 5 mL of eluent have been collected. Determine additional rate checks periodically throughout the test. If the rate is too fast, adjust the needle value as necessary to maintain the specified rate. If the rate is found to be below the prescribed limit, connect the pressure line to the top of the column and apply pressure to adjust to the specified rate. (Warning--See Note AI.2.)

A1.3 Apparatus A I.3.1 Azobenzene Percolation Column, glass constructed from 12.0-mm outside diameter and 6.0-mm outside diameter standard glass tubing with a reservoir of approximately 125 mL near the top. The top of the column shall be a female spherical ground-glass joint. The bottom of the column has a stopcock with internal metering valve attached by means of a standard taper joint. The entire percolation assembly is illustrated in Fig. 3. A1.3.2 Graduated Cylinders, 5 or 10-mL capacity, 0.1mL graduation. A1.3.3 Gas or Air Pressure System, regulated. A1.3.4 Vibrator, electric. The type of tungsten carbide tipped vibrating pencil used for marking glass is satisfactory if a rubber stopper is slipped over the tip. AI.3.5 Spectrophotometer, capable of operation at 446mm wavelength, 14 equipped with a l-mm (or 0.5-mm) thickness cell.

NOTE AI.2: Warning--Normally only light pressure will be required; that is 5 to 15 mm Hg. At test termination, the number of minutes required to collect the eluent should not differ from the millilitres of eluent collected by more than two.

A1.5.6 After 25 mL of effluent has been collected, collect at least 6 samples sequentially of 2 mL each. Measure the azobenzene concentration of these samples using the Spectrometer which has been previously calibrated with known concentrations of azobenzene in isooctane, using a wavelength of 446 ram. AI.5.7 Plot the effluent azobenzene concentration versus the effluent volume, and graphically determine the effluent volume at 0.5 mass % azobenzene concentration (50 % of the starting solution concentration). This is the azobenzene equivalence of the clay.

AI.4 Reagents A I.4.1 Azobenzene Solution (1%), prepared by dissolving I0 _ 0.001 g of c.p. azobenzene in 990 g of isooctane. (Warning--See Note A I. 1.) NOTE AI.I: Warning--Azobenzene lsooctane is flammable.

is

a

suspect

carcinogen.

AI.5 Procedure A I.5. I Insert a small piece of glass wool into the bottom of the glass column (6.0-mm outside diameter tubing) and move it up the tubing until top surface is 25 mm (1 in.) from the joint of the two glass sections (see Fig. 3).

A1.6 Interpretation of Results A1.6.1 The average of duplicate determinations of azobenzene equivalence is used to determine the suitability of a clay for use in this test method. If the duplicate azobenzene equivalence values differ by more than l mL, make a third determination and use the average of all three. AI.6.2 A Clay with an average azobenzene equivalence between 30 and 35 meets the activity criterion (see 7.3). Clay with azobenzene equivalence values outside this range is not suitable for use in this test method.

NOTE A I. l--lnsert a sufficient amount of glass wool to hold in place. Fold the glass wool to produce a smooth surface for the top of the plug.

14A Bausch and Lomb Spectronic 20 has been found suitable for this purpose.

316

~t~r~ D 2007 equivalence of clay since the result merely states whether there is conformance to the criteria specified in this test method.

A1.7 Precision and Bias A 1.7.1 No statement is made about either the precision or the bias of this procedure for determining the azobenzene

X1. APPENDIX

(Nonmandatory Information) portions and evaporate the n-pentane on a hot plate at a temperature of I00-I05°C. Rinse the flask with small portions of n-pentane, adding these rinsings to the anti-creep beaker, n-Pentane shall be considered removed when the change in weight is less than I0 mg in I0 min at this temperature. Slow nitrogen flows over the beaker can be used to assist the evaporation, but rapid stirring by the gas should be avoided, X I.I.5 Weigh the recovered oil. The weight of sample (7. I) less the weight of the oil is the asphaltenes content. This oil can then be diluted for charge to the clay-gel column (6.2).

XI.1 Removal of Asphaltenes If the diluted sample of 8.2 is not free from precipitates or flocculate, an approximation of the characteristic groups can be obtained by the following procedure: X l . l . l Weigh l0 + 0.5 g of the sample to the nearest 0.5 mg in a preweighed 250-mL conical flask, add 100 mL of n-pentane and mix well. Warm the mixture in a warm water bath for a few seconds with intermittent swirling to hasten solution. Allow the mixture to stand about 30 min at or near room temperature. Samples containing a high content of insolubles may require more agitation to dissolve the n-pentane-soluble portion. In such cases, use a stirring rod, together with intermittent warming and swirling to hasten solution of the sample. Solution should be cooled to room temperature before filtering. X I. 1.2 Set up a filtering assembly, using a 500-mL flask, a 125-mm borosilicate filtering funnel equipped with a folded rapid 15-cm filter paper, and filter the sample. Rinse the conical flask and stirring rod with 60-mL n-pentane, and pour the rinse through the paper filter. X I. 1.3 Rinse the filter paper and contents with 60 mL of n-pentane in small portions from a dispensing bottle, taking care to rinse down the sides of the filter paper. X l.l.4 Transfer the solution to an anti-creep beaker in

X1.2 Precision and Bias X I.2.1 The precision of this test method was determined by a round robin of too few samples to meet the requirements of Practice E 691. However, it can be approximated as:

Repeatability: 1.3 %; Reproducibility: 7.8 %. XI.2.2 Bias--There is insufficient interlaboratory test data to establish a statistical statement of bias for the procedure in Appendix Xl of Test Method D 2007.

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103.

317

(~i~ Designation: D 2158 - 92

An American NationalStandard

Designation: 3 1 7 / 7 5

Standard Test Method for Residues in Liquefied Petroleum (LP) Gases 1 This standard is issued under the fixed designation D 2158; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (~) indicates an editorial change since the last revision or reapproval.

3.1.3 oilstain observationmthe volume of solvent-residue mixture required to yield an oil ring that persists for 2 min under specified conditions on a prescribed filter paper. 3.1.4 0 Number - - 10 divided by the oil stain observation.

1. Scope 1.1 This test method covers the determination of the extraneous materials weathering above 38"C that are present in liquefied petroleum gases. 1.2 Liquefied petroleum gases that contain alcohols to enhance their anti-icing behaviour can give erroneous results by this test method. 1.3 The result can be expressed in terms of measured volumes or indices derived from these volumes. In either case, the test method provides an indication of the quantity and nature of materials in the product that are substantially less volatile than the liquefied petroleum gas hydrocarbons. 1.4 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific precautionary statements, see 6.9.

4. Summary of Test Method 4.1 A 100-mL sample of liquefied petroleum gas is weathered in a 10O-mL centrifuge tube. The volume of residue remaining at 38°C is measured and recorded as is also the appearance of a filter paper to which the residue has been added in measured increments. 5. Significance and Use 5.1 Control over the residue content (required by Specification D 1835) is of considerable importance in end-use applications. In liquid feed systems residues may lead to troublesome deposits and, in vapor ofPtake systems, residues that are carried over can foul regulating equipment. Those that remain will accumulate, can be corrosive, and will contaminate following product. Water, particularly if alkaline, can cause failure of regulating equipment and corrosion of metals.

2. Referenced Documents 2.1 A S T M Standards: D 96 Test Methods for Water and Sediment in Crude Oil by Centrifuge Method (Field Procedure) 2 D 1796 Test Method for Water and Sediment in Fuel Oils by Centrifuge Method (Laboratory Procedure) 2 D 1835 Specification for Liquefied Petroleum (LP)Gases 2 E 1 Specification for ASTM Thermometers 3 2.2 Other Document: GPA Publications 21404 IP Appendix A5

6. Apparatus 6.1 Centrifuge Tube, 100-mL graduated, conforming to dimensions given in Fig. 1. The first 0.5 mL shall be graduated in 0.05-mL increments. The shape of the lower tip of the tube is especially important. The taper shall be uniform and the bottom shall be rounded as shown in Fig. 1. Tubes shall be made of thoroughly annealed heat-resistant glass. Volumetric graduation tolerances, based on air.free water at 20"C, are given in Table 1. Detailed requirements for centrifuge tubes appear in Test Methods D 96 and D 1796. 6.2 Cooling Coil a minimum length of 6 m of 5 to 7-mm outside diameter copper tubing wound to a diameter of 63.5

3. Terminology 3.1 Descriptions of Terms Specific to This Standard: 3.1.1 residue--the volume, measured to the nearest 0.05 mL, of the residual material boiling above 38"C resulting from the evaporation of 100 mL of sample under the specified conditions of this test method. 3.1.2 R Number--the residue multiplied by 200.

TABLE 1.

This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum P~oduets and Lubricants and is the direct responsibility of Subcommittee D02.H on Liquid Petroleum Gas. Current edition approved Apr. 15, 1992. Published June 1992. Originally pubhshed as D 2158 - 63 T. Last previous edition D 2 t 58 - 89. Annual Book of ASTM Standards, Vol 05.01. 3 Annual Book of ASTM Standards, Vol 14.03. 4 Available from Gas Processors Assn., 1812 First Place, Tulsa, OK 74103. s Available from Institute of Petroleum, 61 Cavendish St., London, NIM 8AR.

318

Centdfuge Tube Graduation Tolerances

Range, mL

Scale, Division, mL

Limit of Error, mL

0.0 to 0.1 0.1 to 0.3 0.3 to 0.5 0.5 to 1.0 1.0 to 3.0 3.0 to 5.0 5.0 to 25.0 25.0 to 100.0

0,05 0.05 0.05 0,1 0.1 0.5 1.0 1,0

0.02 0.03 0.05 0.05 0.1 0.2 0.5 1.0

~

D 2158

CopperWire 3rnm NEEDLEVALVE SAMPLE VALVE

=m 10 6ram SAMPLE LINE

7-10 m

-T emOF fuwn O.D. SOFT COPPERTUSlNG

COOLINGVESSEL 36.00-37 75 mm OO

195,-203 mm m I

10 mL

$Smm

82-90 m= NOTE--Coils in the drawing are extended for clarity. FIG. 2 Precooling Equipment

Vl

1

6.8 Copper Wire, 1.6 ± O.l-mm diameter, 300 ± lO-mm. 6.9 Clamp, suitable for holding the centrifuge tube during weathering.

'°7 V Line of inside bettom

7. Reagents and Materials 7.1 Solvent--Oil-free, reagent-grade pentane or cyclopentane. NOTE 2--Although pentane is the preferred solvent for use in this test method, eyclopentane can be substituted for pentane whenever the ambient temperature or altitude is too high to enable the convenient handling of pentane.

INSIDE TAPER SHAPE FIG. 1 Cone-Shaped Centrifuge Tube, 203 mm

± 1.5 mm outside diameter, and assembled in a suitable cooling bath. (See Fig. 2.) 6.3 Syringe, l-mL (ordinary medical syringe), graduated in 0.1 m L and equipped with a needle 200 ± 5 m m long. Alternatively, a 0. l-mL pipet may be used. 6.4 Thermometers, conforming to Specification E I or IP Appendix A. Low Range-Minus 38"C to +50"C High Range-Minus 20"C to +50"C

8. Preparation of Apparatus 8.1 Wash all glassware that is to be used in the test in the selected solvent. Add 10 m L of a new sample of solvent to the centrifuge tube. Mark the center of the filter paper. Fill the syringe or pipet with a portion of the solvent drawn from the centrifuge tube and direct 0.1 m L of the solvent to the mark on the paper. Allow the solvent to evaporate and note the persistence of an oil ring. Attempt to cover a circle of about 30 to 35 m m in diameter on the filter paper with each addition. If no oil ring appears after 1.5 mL of solvent has been added, the solvent and glassware are satisfactory. The appearance of an oil ring indicates either improperly cleaned glassware or contaminated solvent.

lP IC/ASTM 5C ASTM57C

NOTE l--When a thermometer or a water bath, or both, are not available, for example, a field test, a satisfactoryalternative for screening is to warm the tip of the centrifuge tube with the hand. 6.5 Filter Paper, medium-grade, rapid, white, 125-ram diameter. 6.6 Solvent Wash Bottle. 6.7 Water Bath, controlled at 38 ± 2"C. 319

o alsa 8.2 The presence of an oil ring should be observed by holding the dry filter paper between the eye and a bright incandescent light or strong daylight. 8.3 The solvent is added in 0. l-mL increments to confine the solvent ring to a circle of about 30 to 35 mm in diameter. The filter paper should be held level during the solvent addition. One method is to place it on the 250-mL beaker. 9. Procedure 9.1 Residue--Attach the cooling coil to the sample source, cool the coil to below the boiling point of the sample, and flush the coil and sampling line. 9.1.1 Rinse the centrifuge tube with the material to be sampled and then fill it to the 100-mL mark with a representative sample. 9.1.2 Immediately insert the copper wire through a clean, slotted cork or a clean, loose-fitting plug of cotton or cleansing tissue in the mouth of the centrifuge tube. The wire helps to prevent superheating and resulting bumping (erratic or excessive boiling), and the cork (or plug) will keep out air or moisture while the sample is weathering. If more than 10 mL of the sample is lost because of bumping, obtain a new sample. 9.1.3 Allow the sample to weather, using artificial heating, if the ambient temperature or type of sample requires it. If, when weathering has ceased and the tube has reached ambient temperature, a residue remains, place the tip of the tube in a water bath at 38"C for 5 rain. 9.1.4 Record the volume of any remaining residue to the nearest 0.05 mL, and the presence of extraneous matter, if observed. 9.2 Oil Stain Observation--Add sufficient solvent to the centrifuge tube containing the residue described in 9.1.4 to restore the volume to 10 mL. Add the solvent from the wash bottle and carefully wash down the sides of the tube. Stir well with the syringe needle or pipet so that any residue at the bottom of the tube is dissolved uniformly in the solvent. 9.2.1 Mark the center of a clean white filter paper. Fill the syringe or pipet and direct 1.5 mL of the solvent-residue mixture at a rate such that the wetted circle is maintained at about 30 to 35 mm in diameter. 9.2.2 If no oil ring persists after a 2-min waiting period when holding the dry filter paper between the eye and a bright incandescent light or strong daylight, discontinue the test. 9.2.3 If a ring is discernible, determine the volume of the solvent-residue mixture at which the oil ring first persists for 2 min on a new filter paper by adding the solvent-residue mixture in 0.1-mL increments. 9.2.4 Record the volume in mL of the solvent-residue mixture required to yield a persistent oil ring as the oil stain observation. 9.3 Storage of oil-free solvent in a polyethylene wash bottle for several days contaminates the solvent. Any solvent transferred to the wash bottle for purposes of running the test should either be used in testing during the same day or discarded. 9.4 It has been noted that at low ambient temperatures (below about 5"C) materials in the gasoline boiling range will leave an oil rilag that persists after 2 min. Oil ring determinations should be made in a protected area where the 320

temperature is above 5"C. If it is necessary to determine the oil ring at temperatures below 5"C, allow 10 rain for oil ring persistence. NOTE 3--As an acceptablealternativeto the proceduregiven in 9.2 for use in those cases where a product specification limit has been established, continued incremental additions of the solvent-residue mixture that is equivalentto the limitingspecificationcan be made to the filterpaper and, if no persistent oil ringappears, the resultofthe test shall be reported as passing.

10. Calculation 10.1 R Number--Multiply the volume of residue obtained in 9.1.4 by 200. 1 0 . 2 0 Number--Divide 10 by the oil stain observation obtained in 9.2.4. If the oil stain observation exceeds 1.5 mL, the result is recorded as zero. 11. Expression of Results 11.1 Volumetric--The results shall be expressed as: 11.1.1 Residue on evaporation to the nearest 0.05 mL, and 11.1.2 Oil stain observation to the nearest 0.1 mL. 11.2 Normalized--The results shall be expressed as: 11.2.1 R Number to the nearest I0, and 11.2.20 Number to the nearest 1. 12. Precision and Bias 12.1 Precision is only expressed in terms of the normalized reporting units. 12.2 Repeatability---The difference (r) between successive test results obtained by the same operator with the same apparatus under constant operating conditions on identical test material would, in the long run, in the normal and correct operation of the test method, exceed the values below only in one case in twenty: 0 Number

r

R Number

r

0 to 20 20 to 40 40 to 100

4 6 8

0 to 20 20 to 40 40 to 60

5 10 20

12.3 Reproducibility--The difference (R) between two test results independently obtained by different operators operating in different laboratories on nominally identical test material would, in the long run, in the normal and correct operation of the test method, exceed the values below only in one case in twenty: 0 Number

R

R Number

R

0 t o 20 20 to 40 40 to 100

6 8 12

0to20 20 to 40 40 to 60

10 20 30

12.4 B/as--The procedure in this test method for measuring residues in LP-Gas has no bias because the residues are defined only in terms of this test method.

13. Keywords 13.1 liquified petroleum gases; LPG; residue

~) D 2158 The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reepproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend, ff you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103.

321

Designation: D 2163 - 91 (Reapproved 1996)

@

An American National Standard

Designation: 264/79 (85)

Standard Test Method for Analysis of Liquefied Petroleum (I.P) Gases and Propene Concentrates by Gas Chromatography 1 This standard is issued under the fixed designation D 2163; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (~) indicales an editorial change since the last revision or reapproval.

1. Scope 1.1 This test method covers the determination of the composition of liquefied petroleum (LP) gases. It is applicable to analysis of propane, propene, and butane in all concentration ranges 0.1% and above. 1.2 This standard does not purport to address all of the

safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 1.3 The values stated in SI units are to be regarded as standard. 2. Referenced Documents 2.1 A S T M Standards: D 2421 Practice for Interconversion of Analysis of C5 and Lighter Hydrocarbons to Gas-Volume, Liquid-Volume, or Weight Basis2 D 2598 Practice for Calculation of Certain Physical Properties of Liquified Petroleum (LP) Gases from Compositional Analysis 3 D 3700 Practice for Containing Hydrocarbon Fluid Samples Using a Floating Piston Cylinder 3

5.1 The component distribution of liquefied petroleum gases and propene concentrates is often required as a specification analysis for end-use sale of this material. Its wide use as chemical feedstocks or as fuel, require precise compositional data to ensure uniform quality of the desired reaction products. 5.2 The component distribution data of liquefied petroleum gases and propene concentrates can be used to calculate physical properties such as relative density, vapor pressure, and motor octane (see Practice D 2598). Precision and accuracy of compositional data are extremely important when these data are used to calculate various properties of these petroleum products.

6. Gas Chromatograph System

3. Terminology 3.1 Definition:

3.1.1 propene concentrate---concentrate

5. Significance and Use

containing more

than 50 % propene.

4. Summary of Test Method 4.1 Components in a sample of LP gas are physically separated by gas chromatography and compared to corresponding components separated under identical operating conditions from a reference standard mixture of known composition or from use of pure hydrocarbons. The chromatogram of the sample is interpreted by comparing peak heights or areas with those obtained on the reference standard mixture of pure hydrocarbons. 1 This test method is under the jurisdiction of ASTM Committee I)-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.D0.03 on C4 Test Methods Liquefied Petroleum Gas. Current edition approved Oct. 15, 1991. Published December 1991. Originally published as D 2163 - 63. Last previous edition D 2163 - 87. 2 Annual Book of ASTM Standards, Vol 05.01. 3 Annual Book of ASTM Standards, Vol 05.02.

322

6.1 Detector--The detector shall be a thermal conductivity type or its equivalent in sensitivity and stability. The system shall be capable of detecting 0.1% concentration of any component of interest. For calculation techniques utilizing a recorder, the signal for the concentration shall be at least 5 chart divisions above the noise level on a 0 to 100 scale chart. Noise level must be restricted to a maximum of 1 chart division. When electronic integration is employed the signal for 0.1% concentration must be at least twice the noise level. 6.2 Recorder A strip-chart recorder and integrator with a full-scale range of 10 mV or less shall be required. A maximum full-scale balance time of 2 s and a minimum chart speed of 1/2 in. (12.7 mm)/min shall be required. 6.3 Attenuator--A multistep attenuator for the detector output signal shall be necessary to maintain maximum peaks within the recorder chart range. The attenuator system must be accurate to 0.5 % in any position. 6.4 Sample Inlet System--Provision shall be made to introduce up to 0.50 mL of the sample. The sample volume must be repeatable such that successive runs agree within 1 m m or 1% (whichever is larger) on each component peak height. 6.5 Temperature Control--The analyzer columns shall be maintained at a temperature constant to 0.30C during the course of the sample and corresponding reference standard runs.

~ TABLE 1 Component

Propane with No

Unsaturates Ethane Propane Propene n-Butane Isobutane Butane Isopantane

Reference Standard Mixtures, Liquid Volume Percent A Propane with Low Propene

Propane with High Propene

4 87 4 1 3

3 57 35 1 3

4 93 ... 1 1 .

.

D 2163

.

'1

.

.

.

"1

1

Butane

"3" ... 64 25 6 2

PropaneButane Mixtures

Propene with Low Propane

Propene with High Propane

2 45 6 30 15 _ "2"

0.2 4.8 94.9 0.1 ... ... .. .

0.1 22.6 76.6 0.5 0.2 .

.

.

A The composition values recorded in this table are offered as a guide to laboratoriespreparing their own mixtures from pure hydrocarbons or to commercial suppliers of standards. In either case, an accurate composition of the standards must be known to analyst.

7. Calibration Standard

FIG. 1

Illustration o f

7.1 Pure components or calibration standard mixtures 4 may be used for calibration. If pure components are used, identical volumes of each component are injected into the chromatograph and relative area response factors are determined. These factors are valid for a given instrument and operating conditions and should be redetermined periodically. If pure components are used for calibration, the calculation should be made in mole percent and converted to liquid volume percent (Note 1). Factors repeatable to within 1% are required. The concentration of each component in the calibration standard mixtures shall be known to within 0.1%. The concentration of the major component in the calibration standard mixture shall not differ from that of the like component in the sample to be analyzed by more than 10 % if the peak height method of calculation is used. On propene concentrates, the calibration standard mixtures shall not differ from that of like component in the sample to be analyzed by more than 5 %. Typical composition ranges of suitable calibration standard mixtures are given in Table 1.

A/B Ratio

6.6 Carrier Gas--The instrument shall be equipped with suitable facilities to provide a flow of carrier gas through the analyzer column at a flow rate that is constant to 1.0 % throughout the analysis. 6.7 Columns--Any column may be used provided all component peaks for compounds present in concentration of more than 5 % are resolved so that the ratio A/B shall not be less than 0.8,

NOTE 1--Test Method D 2421 m a y be used whenever a need exists

for such translations. 8. Procedure

where: A = depth of the valley on either side of peak B, and B = height above the baseline of the smaller of any two adjacent peaks (see Fig. l). For compounds present in concentrations of 5 % or less, the ratio of A/B shall not be less than 0.4. In case the smallcomponent peak is adjacent to a large one, it may be necessary to construct the baseline of the small peak tangent to the curve as shown in Fig. 2.

FIG. 2

Illustration of

8.1 Apparatus Preparation--Mount the column suitable for the analysis desired (see Appendix X1) in the chromatograph and adjust the conditions to optimum for the column selected (Table 2). Allow sufficient time for the instrument to reach equilibrium as indicated by a stable base line. 8.1.1 The test method allows the user a wide latitude in choice of instrumentation to make the analysis, and most commercial instrumentation easily meets the requirements defined in the test method. However, only by strict adherence to the calibration procedures outlined in the method can reproducibility between instruments expect to be achieved. 8.1.2 Proper maintenance of instrumentation is critical to continued satisfactory performance of this analysis. Clean sample containers, clean sample inlet systems and clean detectors are mandatory to achieve the precision and accuracy capabilities of this method. NOTE 2: Warning--Samples and reference mixtures are extremely flammable. Keep awayfrom heat, sparks, and flames. Use with adequate 4 Suitable reference standard mixtures of pure hydrocarbons are available from the Phillips Petroleum Co., Special Products Div., Bartlesville, OK.

A/B Ratio for Small-Component Peak 323

q~) D 2 1 6 3 TABLE 2

Column Diameter, mm, OD

Substrate,

Temperature,

Mass, %

4 9 9 7

6.4 6.4 6.4 6.4

15 6 4 9 9

6.4 3.2 6.4 6.4 6.4

Column

Length, rn Silicon 200/500 Banzyl cyanide--silver nitrate Hexamathylphosphoramide Dimethylsulfolane plus banzyl cyanide and silver nitrate Dimethylsulfolane Hexamathyl phosphorernide Din-butyl maleate Tricresyl phosphate plus siUcone, 550 Mathoxy ethoxy ethyl ether TABLE 3

Instrument Conditions

*C

Flow Rate, mL/min

Carrier G

27 36 17 36

90 40 30 35

60 to 70 45 to 55 60 to 70 60 to 70

helium helium helium helium

30 25 25 30 30

25 28 28 35 30

30 12 60 70 60

helium helium helium helium helium

Precision Date for LPG Containing Less Than 50 % Propene

Concentration Range of Components, mo~

Repeatability

Reproducibility

0 to 70 Above 70

use repeatabmitycurve in Fig. 3 0.2

use reproducibility curve in Fig. 3 1 ~ of amount present

ventilation. Cylinders must by supported at all times. Hydrocarbon vapors that may be vented must be controlled to assure compliance with appficable safety and environmental regulations. Vapor reduces oxygen available for breathing. Liquid causes cold burns.

8.2 Preparation and Introduction of Sample--Attach the cylinder containing the gas mixture to the sampling valve of the chromatograph so that a liquid phase sample is withdrawn. Adjust the flow rate from the sample cylinder so that complete vaporization of the liquid occurs at the cylinder valve. (An alternative technique is to trap a sample of only liquid phase in a short section of tubing, and then permit the entire sample to vaporize into an evacuated container). Adjust the ratio of the two volumes so that a gage pressure of 69 to 138 kPa (10 to 20 psi) is obtained in the final container. Then use this sample for the analysis. Flush the sample loop for 1 to 2 min at a flow rate of 5 to 10 m L / m i n before introducing the sample into the carrier gas stream. 8.2.1 On propene concentrates, the sample may be introduced as a liquid by means of a liquid sample valve or by vaporization of the liquid as above. On propene concentrates having a propene content of less than 80 %, only the alternative technique of trapping a sample of liquid and vaporizing the entire sample into an evacuated container shall be used. 8.2.2 Sampling at the sample source and at the chromatograph must always be done in a manner that ensures that a representative sample is being analyzed. Lack o f precision and accuracy in using this method can most

Ethane Propene Propane Butanes

Butanes

Concentration, tool % 0.0 to 0.1 0.2 70 to 77 93 to 95 5 to 7 22 to 29 0.0 to 0.1 0.5 0.6 1 0.2

where: Ps = peak height of component in the sample, Po = peak height of component in reference standard mixture, and S = percentage of mole or liquid volume of component in reference standard mixture. 9.2 Area Method--Measure the area of each component by multiplying the height of the peak by the width at half height. The width should be measured with the aid of a magnifying glass (Note 3). Adjust the area to the attenuation of the same component in the reference standard mixture. NOTE 3--The use of planimeters or integrators is permissible provided their repeatability has been established and the resulting repeatability does not adversely affect the repeatability and reproducibility limits of the method given in Section 10.

Repeatability Reproducibility 0.02 0.05 0.38 0.34 0.33 1.0 0.04 0.04 0.1 0.1 0.07

8.3 Preparation of the Chromatogram--Obtain duplicate chromatograms of the sample. Adjust the attenuator at each peak for maximum peak height within the recorder chart range. Peak heights of like components shall agree within 1 m m or 1% (whichever is larger). If a reference standard mixture is used for calibration, obtain duplicate chromatograms of the proper reference standard in a similar manner. Use the same sample size for all runs. 9. Calculation 9.1 Peak Height Method--Measure the peak height of each component and adjust this value to the attenuation of the same component in the reference standard mixture. Calculate the percentage by mole or liquid volume of each component as follows: Concentration, liquid volume or tool percent = (PJPo) x S

TABLE 4 Precision Date for Propene Concentrates Compound

often be attributed to improper sampling procedures. (See Test Method D 3700.)

0.04 0.06 1.5 1.0 1.0 1.7 0.08 0.2 0.3 0.5 0.2

9.2.1 Calculate the percentage by mole or liquid volume of each component as follows: Concentration, liquid volume or mol percent -- (As/Ao) x S where: As = area of component in sample, A o = area of component in reference standard mixture, and 324

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Precision, 95 Percent Confidence Lillt

FIG. 3 PrecisionCurves S

ffi percentage by mole or liquid volume of component in reference standard mixture. 9.2.2 If pure components are used for calibration, calculate the composition as follows: Concentration, mol percent AsIAp where: As = area of component in sample, m m 2, and Ap = area sensitivity of component, m m 2 per percent. 9.2.3 Total the results and normalize to 100 %. 9.3 Normalization--Normalize the mole or liquid volume percent values obtained in 9.1 or 9.2 by multiplying each value by 100 and dividing by the sum of the original values. The sum of the original values should not differ from 100.0 % by more than 2.0 %.

10.1 The data in Table 3 and Fig. 3 shall be used for

judging the acceptability of results (95 % confidence) on samples containing less than 50 % propene. The data in Table 4 shall be used for judging the acceptability of results on samples containing more than 50 % propene. 10.1. l Repeatability---The difference between successive test results, obtained by the same operator with the same apparatus under constant operating conditions on identical test material, would in the long run, in the normal and correct operation of the test method exceed the values shown in Table 3 or Fig. 3 and Table 4 in only one case in twenty. lO.l.2 Reproducibility--The difference between two single and independent results, obtained by different operators working in different laboratories on identical test material, in the normal and correct operation of the test method, exceed the values shown in Table 3 or Fig. 3 and Table 4 in only one case in twenty. 10.2 Bias--Since there is no accepted reference material suitable for determining the bias for the procedure in this test method, no statement on bias is being made.

5 The data from which this precision statement is based are not available.

11. Keywords 11.1 analysis; liquified petroleum gas

=

10. Precision and Bias s

325

t~,) D 2163

APPENDIX

(NonmandatoryInformation) Xl. PARTITION C O L U M N S X I. 1 The following four partition columns have been cooperatively tested and found suitable for use with materials given in the scope of this test method. X I. I. l Silicone 200/500 Column--This column separates ethane, propane, n-butane, isobutane, n-pentane, and isopentane and is therefore suitable for analyzing LP gases free from unsaturated hydrocarbons. X l . l . 2 Benzyl Cyanide-Silver Nitrate Column--This column separates isobutane, n-butane, the butenes, n-pentane and isopentane, and accordingly is best suited for use with LP gas butane containing unsaturated C4 hydrocarbons. X l . I . 3 Hexamethylphosphoramide (HMPA) Column-This column separates ethane, propane, propene, isobutane,

n-butane, the butenes, n-pentane, and isopentane, and accordingly is suitable for use with all types of LP gases. X l . l . 4 Dimethylsufolane (DMS)-Benzyl Cyanide-Silver Nitrate Column--This column separates all components in commercial LP gases. NOTE Xl.l--There are commercial suppliers of gas chromatography equipment and columns who can make (and guarantee) that the columns they provide will meet the specifications(see 6.7 Columns) of this test method. NOTe XI.2: Warning--toxic. Precanden~S~ the product safety bulletins from the supplier of the chemicals used in preparing these columns or before BenzylCyanide-SilverNitrate Column; X 1.1.3 Hexamcthylphosphoramide (HMPA) column, and X 1.1.4 Dimethylsufolane (DMS) Benzyl Cyanide-SilverNitrate Column.

The American Society for Testing and Materials takes no position ~ i n g the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, end the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and ff not revised, either reepproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend, ff you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 100 Barr Harbor Drive, West C o n s ~ k e n , PA 19428.

326

~l~ ) Designation: D 2171 - 94

IPq Designation:222/68 Iiii IN~IIIIIII OJ M J # ~ . I O M

Standard Test Method for Viscosity of Asphalts by Vacuum Capillary Viscometer I This standard is issued under the fixed designation D 2171; the number im mediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (~) indicates an editorial change since the last revision or reapprovai. This is also a standard of the Institute of Petroleum issued under the fixed designation IP 222.The final number indicates the year of last revision.

This test method has been approved by the sponsoring committees and accepted by the cooperating societies in accordance with established procedures.

1. Scope I. 1 This test method covers procedures for the determination of viscosity of asphalt (bitumen) by vacuum capillary viscometers at 140*F (60"C). It is applicable to materials having viscosities in the range from 0.036 to over 200 000 P. NOTE l--This test method is suitable for use at other temperatures, but the precision is based on determinations on asphalt cements at 140*F (60"C). 1.2 This standard does not purport to address all of the

safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 2. Referenced Documents

ASTM Standards:

4. Summary of Test Method 4.1 The time is measured for a fixed volume of the liquid to be drawn up through a capillary tube by means of vacuum, under closely controlled conditions of vacuum and temperature. The viscosity in poises is calculated by multiplying the flow time in seconds by the viscometer calibration factor. NOTE 2--The rate of shear decreasesas the liquid moves up the tube, or it can also be varied by the use of different vacuum or different size viscometer. Thus, this method is suitable for the measurement of viscositiesof Newtonian (simple) and non-Newtonian (complex) liquids. 5. Significance and Use 5. I The viscosity at 60"C (140°F) characterizes flow behavior and may be used for specification requirements for cutbacks and asphalt cements.

E I Specification for ASTM Thermometers 2 E 11 Specification for Wire-Cloth Sieves for Testing Purposes 3 E 77 Test Method for Inspection and Verification of Liquid-In-Glass Thermometers 2

6. Apparatus

6.1 Viscometers, capillary-type, made of borosilicate glass, annealed, suitable for this test are as follows: 6.1. I Cannon-Manning Vacuum Viscometer (CMVV), as described in Appendix X 1. 6.1.2 Asphalt Institute Vacuum Viscometer (AIVV), as described in Appendix X2. 6.1.3 Modified Koppers Vacuum Viscometer (MKVV), as described in Appendix X3. Calibrated viscometers are available from commercial suppliers. Details regarding calibration of viscometers are given in Appendix X4. NOTE 3uThe viscositymeasured in a CMVV may be from I to 5 % lower than either the AIVV or MKW having the same viscosityrange. This difference,when encountered, may be the result of non-Newtonian flow.4

3. Terminology 3.1 Definitions: 3.1.1 Newtonian liquidDa liquid in which the rate of shear is proportional to the sheafing stress. The constant ratio of the shearing stress to the rate of shear is the viscosity of the liquid. If the ratio is not constant, the liquid is non-Newtonian. 3.1.2 viscosity~the ratio between the applied shear stress and rate of shear is called the coefficient of viscosity. This coefficient is thus a measure of the resistance to flow of the liquid. It is commonly called the viscosity of the liquid. The cgs unit of viscosity is 1 g/cm. s (1 dyne. s/cm 2) and is called a poise (P). The SI unit of viscosity is 1 Pa. s (1 N. s/m 2) and is equivalent to I0 P.

6.2 ThermometersDCalibrated liquid-in-glass thermometers (see Table X4.2) of an accuracy after correction of 0.04°F (0.020C) can be used or any other thermometric device of equal accuracy. ASTM Kinematic Viscosity Thermometers 47F and 47C are suitable for the most commonly used temperature of 140"1: (60°C). 6.2.1 The specified thermometers are standardized at "total immersion," which means immersion to the top of the mercury column with the remainder of the stem and the

This test method is under the jurisdiction of ASTM Committee D-4 on Road and Paving Materials and is the direct responsibility of Subcommittee D04.44 on Rheologlcal Tests. In the IP this test method is under the jurisdiction of the Standardization Committee. Current edition approved Feb. 15, 1994. Published April 1994. Originally published as D 2171 - 63 T. Last previous edition D 2171 - 92. 2Annual Book of ASTM Standards, Vol 14.03. a Annual Book of ASTM Standards, Vol 14.02.

4 Supporting data are available from ASTM Headquarters, 1916 Race St., Philadelphia, PA 19103. Request RR:D04-1003.

327

(@1 D 2171 expansion chamber at the top of the thermometer exposed to room temperature. The practice of completely submerging the thermometer is not recommended. When thermometers are completely submerged, corrections for each individual thermometer based on calibration under conditions of complete submergence must be determined and applied. If the thermometer is completely submerged in the bath during use, the pressure of the gas in the expansion chamber will be higher or lower than during standardization, and may cause high or low readings on the thermometer. 6.2.2 It is essential that liquid-in-glass thermometers be calibrated periodically using the technique given in Test Method E 77 (see Appendix X5). 6.3 Bath--A bath suitable for immersion of the viscometer so that the liquid reservoir or the top of the capillary, whichever is uppermost, is at least 20 mm below the upper surface of the bath liquid and with provisions for visibility of the viscometer and the thermometer. Firm supports for the viscometer shall be provided. The efficiency of the stirring and the balance between heat losses and heat input must be such that the temperature of the bath medium does not vary by more than +0.05°F (+0.03"C) over the length of the viscometer, or from viscometer to viscometer in the various bath positions. 6.4 Vacuum System--A vacuum system5 capable of maintaining a vacuum to within 4-0.5 mm of the desired level up to and including 300 mm Hg. The essential system is shown schematically in Fig. 1. Glass tubing of 6.35-mm ('/4-in.) inside diameter should be used, and all glass joints should be airtight so that when the system is closed, no loss of vacuum is indicated by the open-end mercury manometer having l-mm graduations. A vacuum or aspirator pump is suitable for the vacuum source. 6.5 Timer--A stop watch or other timing device graduated in divisions of 0.1 s or less and accurate to within 0.05 % when tested over intervals of not less than 15 min. 6.6 Electrical Timing Devices may be used only on electrical circuits, the frequencies of which are controlled to an accuracy of 0.05 % or better. 6.6.1 Alternating currents, the frequencies of which are intermittently and not continuously controlled, as provided by some public power systems, can cause large errors, particularly over short timing intervals, when used to actuate electrical timing devices. 7. Sample Preparations

7.1 Heat the sample with care to prevent local overheating until it has become sufficiently fluid to pour, occasionally stirring the sample to aid heat transfer and to assure uniformity. 7.2 Transfer a minimum of 20 mL into a suitable container and heat to 275 _+ 10*F (135 4- 5.5"C), stirring occasionally to prevent local overheating and taking care to avoid the entrapment of air. s The vacuum control system marketed by Cannon Instrument Co., P. O. Box 16, State College, PA 16801, has been found satisfactory for this purpose.

328

All Tubtng is Gloss 6 . 3 5 mm ( I / 4 i n . OD)

~ G l o s s Open-End Mercury Manometer

,Jo°mete,

Cartesian Monostot

~- Borosd~cote '~ Gloss

(Optional)--

Stopcocks

Bleed

Valve

~ ' T o Vacuum Pump I-Liter Surge Tank

I-Liter SurQe Tank

FIG. 1 Suggested Vacuum System for Vacuum Capillary Viscometers NOTE 4--If it is suspected that the sample may contain solid material, strain the meltedsample into the containerthrough a No. 50 (300-~m) sieveconformingto No. 50 SpecificationE l 1. 8. Procedure

8. l The specific details of operation vary somewhat for the various types of viscometers. See the detailed descriptions of viscometers in Appendixes X I to X3 for instructions for using the type of viscometer selected. In all cases, however, follow the general procedure described in 8.1.1 to 8.1.9. 8.1.1 Maintain the bath at the test temperature within +0.05°F (+0.03°C). Apply the necessary corrections, if any, to all thermometer readings. 8.1.2 Select a clean, dry viscometer that will give a flow time greater than 60 s, and preheat to 275 + 10°F (135 + 5.5°C). 8.1.3 Charge the viscometer by pouring the prepared sample to within +2 mm of fill line E (Figs. 2, 3, and 4). 8.1.4 Place the charged viscometer in an oven or bath maintained at 275 4- 10*F (135 4- 5.5"C) for a period of 10 42 min, to allow large air bubbles to escape. 8.1.5 Remove the viscometer from the oven or bath and, within 5 min, insert the viseometer in a holder, and position the viscometer vertically in the bath so that the upper most timing mark is at least 20 mm below the surface of the bath liquid. 8.1.6 Establish a 300 4- 0.5-ram Hg vacuum below atmospheric pressure in the vacuum system and connect the vacuum system to the viscometer with the toggle valve or

(1~ D 2171 To Vacuum

~/acuum

_~ (-- Fdhng Tube-A

Vacuum

,e

Vacuum Tube-M Ground Glass Jotnt-N ---~ 24/40

~22~

UJ

Filling Tube-A --~-

230 To 2 6 0

Overflow ThLrd Timing

Second Timing

Fourth Timing Mork-I

First Timing

Th*rd Timing Mork-H

Bulb-D Bulb-C-Second Timing Mark-G---

Bulb-B First Timing Mark-F-Fill Line-E 7

Cop

5' All dimensions are in millimetres.

All dimensions are in milhmetres. FIG. 2

FIG. 4

Cannon-Manning Vacuum Capillary Viscometer

stopcock closed in the line leading to the viscometer. 8.1.7 After the viscometer has been in the bath for 30 _ 5 rain, start the flow of asphalt in the viscometer by opening the toggle valve or stopcock in the line leading to the vacuum system. 8.1.8 Measure to within 0.1 s the time required for the leading edge of the meniscus to pass between successive pairs of timing marks. Report the first flow time which exceeds 60 s between a pair of timing marks, noting the identification of the pair of timing marks. 8.1.9 Upon completion of the test, clean the viscometer thoroughly by several rinsings with an appropriate solvent completely miscible with the sample, followed by a completely volatile solvent. Dry the tube by passing a slow stream of filtered dry air through the capillary for 2 min, or until the last trace of solvent is removed. Periodically clean the instrument with a strong acid cleaning solution to remove organic deposits, rinse thoroughly with distilled water and residue-free acetone, and dry with filtered dry air. 8.1.9.1 Chromic acid cleaning solution may be prepared by adding, with the usual precautions, 800 mL of concentrated sulphuric acid to a solution of 92 g of sodium dichromate in 458 mL of water. The use of similar commercially available sulphuric acid cleaning solutions is acceptable. Nonchromium-containing, strongly oxidizing acid cleaning solutions6 may be substituted so as to avoid the disposal problems of chromium-containing solutions.

~ To Vacuum

I

Vac

'

<--Fdhng Tube-;A

•* 22~

250 TO 2 6 0

Fourth Timing M o r k - I ---~" -

Bulb-D---~

Third Timing Mark-H --~=Bulb-C---~ Second Timing Mork-G "--~

--% ---+ 2O

---I2O

Bulb-B

First Timing M a r k - F ~ 2O __L j

Modified Koppers Vacuum Capillary Viscometer

~'%Fdl

LIne-E

/_ All dimensions are in millimetres.

FIG. 3

A commercial source for a nonchromium-containing cleaning solution is Godax Laboratories Inc., 480 Canal St., New York, NY 10013.

Asphalt Institute Vacuum Capillary Viscometer

329

lip D 2171 10. Report 10.1 Always report the test temperature and vacuum with the viscosity test result. For example, viscosity at 140*F (60"C) and 300 mm Hg vacuum, in poises.

8.1.9.2 Use of alkaline glass cleaning solutions may result in a change of viscometer calibration, and is not recommended. 9. Calculation 9.1 Select the calibration factor that corresponds to the pair of timing marks used for the determination, as prescribed in 8.1.8. Calculate and report the viscosity to three significant figures using the following equation: Viscosity, P = Kt where: K = selected calibration factor, P/s, and t = flow time, s.

11. Precision and Bias 1 I. 1 The following criteria (see Note 1) should be used for judging the acceptability of results (95% probability): 1 I. 1.1 R e p e a t a b i l i t y - - D u p l i c a t e results by the same operator using the same viscometer should not be considered suspect unless they differ by more than 7 % of their mean. 11.1.2 Reproducibility---The results submitted by each of two laboratories should not be considered suspect unless the two results differ by more than 10 % of their mean.

APPENDIXES

(Nonmandatory Information) XI. CANNON-MANNING VACUUM CAPILLARY VISCOMETER ( C M W ) 7,s TABLE X1.1 Standard Viscometer Sizes, Approximate Calibration Factors, K and Viscosity Ranges for Cannon-Manning Vacuum Capillary Viscometers

XI.1 Scope X l. 1.1 The Cannon-Manning vacuum capillary viscometer (CMVV) is available in eleven sizes (Table XI.I) covering a range from 0.036 to 80 000 P. Sizes 10 through 14 are best suited to viscosity measurements of asphalt cements at 140*F (60"C).

Vlscometer Size Number 4 5 6 7 8 9 10 11 12 13 14

Xl.2 Apparatus X I.2.1 Details of the design and construction of CannonManning vacuum capillary viscometers are shown in Fig. 2. The size numbers, approximate bulb factors, K, and viscosity ranges for the series of Cannon-Manning vacuum capillary viscometers are given in Table X1. XI.2.2 For all viscometer sizes, the volume of measuring bulb C is approximately three times that of bulb B. XI.2.3 A convenient holder can be made by drilling two

Approximate Calibration Factor, K, A 300 mm Hg Vacuum, P/s Bulb B

Bulb C

0.002 0.006 0.02 0.06 0.2 0.6 2.0 6.0 20.0 60.0 200.0

0.0006 0.002 0.006 0.02 0.06 0.2 0.6 2.0 6.0 20.0 60.0

Viscosity Range, pn 0.036 to 0.8 0.12 tO 2.4 0.36 to 8 1.2 to 24 3.6 to 80 12 to 240 36 to 800 120 to 2 400 360 to 8 1 200 to 24 000 3 600 to 80 000

'~ Exact calibration factors must be determined with viscosity standards. e The viscosity ranges shown in this table correspond to a filling time of 60 to 400 s, Longer flow times (up to 1000 s) may be used.

7 Griffith, J. M. and Puzinauskas, P., "Relation of Empirical Tests to Fundamental Viscosity of Asphalt Cement and the Relative Precision of Data Obtained by Various Tests Methods," Symposium on Fundamental Viscosity of Bituminous Materials, ASTM STP 328, Am. Soc. Testing Mats., ASTTA, 1962, pp. 20-.44. s Manning, R. E., "Comments on Vacuum Viscometers for Measuring the Viscosity of Asphalt Cements," Symposium on Fundamental Viscosity of Bituminous Materials, ASTM STP No. 328, Am. Soc. Testing Mats., ASTTA, 1962, pp. 44.-47.

holes, 22 and 8 mm in diameter, respectively, through a No. 11 rubber stopper. The center-to-center distance between holes should be 25 mm. Slit through the rubber stopper between holes and also between the 8-ram hole and edge of the stopper. When placed in a 2-in. (5 l-mm) diameter hole in the bath cover, the stopper holds the viscometer in place. Such holders are commercially available.

330

(t~ D 2171 X2. ASPH,~ LT INSTITUTE VACUUM CAPILLARY VISCOMETER (AIVV) 7,a vacuum capillary viscometers are given in Table X2.1. X2.2.2 This viscometer has measuring bulbs, B, C, and D, located on the viscometer arm, M, which is a precision bore glass capillary. The measuring bulbs are 20-mm long capillary segments, separated by timing marks, F, G, H, and L X2.2.3 A convenient holder can be made by drilling two holes, 22 and 8 mm in diameter, respectively, through a No. I l rubber stopper. The center-to-center distance between holes should be 25 ram. Slit through the rubber stopper between the holes and also between the 8-mm hole and edge of the stopper. When placed in a 2-in. (5 l-mm) diameter hole in the bath cover, the stopper holds the viscometer in place. Such holders are commercially available.

X2.1 Scope X2.1. l The Asphalt Institute vacuum capillary viscometer (AIVV) is available in seven sizes (Table X2. l) from a range from 42 to 5 800 000 P. Sizes 50 through 200 are best suited to viscosity measurements of asphalt cements at 140°F

(600C).

X2.2 Apparatus X2.2.1 Details of design and construction of the Asphalt Institute vacuum capillary viscometer ark shown in Fig. 3. The size numbers, approximate radii, approximate bulb factors, K, and viscosity range for the series of Asphalt Institute TABLE X2.1

Standard Viscometer Sizes, Capillary Radii, Approximate Calibration .Factors, K, and Viscosity Ranges for Asphalt Institute yecuum Capillary.Visc?meters

Viscometer Size Number

Capillary Radius, mm

25 50 10P

0.125 0.25 0.50

200 400 400R c

1,0 2.0 2.0

800R c

4.0

Approximate Calibration Factor, K, A 300 mm Hg Vacuum, P/s Bulb B Bulb C Bulb D

1 4 16 64 250 250 1000

2 8

32 128 500 500 2000

0.7 3 10 40 160 160 640

Viscosity Range, pa

2 9 9 38

42 to 180 to 600 tO 400 to 600 to 600 to 1 000 to 5

3 12 52 200 400 800

800 200 800 000 000 000 000

A Exact calibration factors must be determined with viscosity standards. B The viscosity ranges shown in this table correspond to a filling time of 60 to 400 s. Longer flow times (up to 1000 s) may be used. c Special design for roofing asphalts having additional marks at 5 and 10 mm above timing mark, F (see Fig. 3). Thus, using these marks, the maximum viscosity range is increased from that using the bulb B cahbration factor.

X3. MODIFIED KOPPERS VACUUM CAPILLARY VISCOMETER ( M K W ) 9't°'lt X3.2 Apparatus

X3.1 Scope X3.1.1 The Modified Koppers vacuum capillary viscometer (MKVV) is available in five sizes (Table X3.1) covering a range from 42 to 200 000 P. Sizes 50 through 200 are best suited to viscosity measurements of asphalt cements at 140*F (60"C).

X3.2.1 Details of design and construction of the Modified Koppers vacuum capillary viscometer are shown in Fig. 4. The size numbers, approximate radii, approximate bulb factors, K, and viscosity ranges for the series of Modified Koppers vacuum capillary viscometers are given in Table X3.1. X 3 . 2 . 2 This viscometer consists of a separate filling tube,

9Rhodes, E. O., Volkmann,E. W., and Barker,C. T., "New Viscometerfor Bitumens Has Extended Range," Engineering News-Record, Vol I15, No. 21, 1935,p. 714. ~oLewis,R. H. and Halstead,W.J., "Determinationof the KinematicViscosity of PetroleumAsphaltswith a CapillaryTube Viscometer,"Public Roads, Vol 21, No. 7, September1940,p. 127. TABLE X3.1

~ Heithaus,J. J., "Measurementof AsphaltViscositywitha VacuumCapillary Viscometer," Papers on Road and Paving Materials and Symposium on Microviscometry, ASTM STP 309. 1961,p. 63.

Standard Viscometer Sizes, Capillary Radii, Approximate Calibration Factors, K, and Viscosity Ranges for Modified Koppers Vacuum Capillary Viscometers

Viscometer Size Number

Capillary Radius, mm

25 50

0.125 0.25

100 200 400

0.50 1.0 2.0

Approximate Calibration Factor, K, A 300 mm Hg Vacuum, P/s Bulb B

Bulb C

Bulb D

1 4 16 64 250

0.7 3 10 40 .160

2 8

32 128 500

A Exact calibration factors must be determined with viscosity standards. a The viscosity ranges shown in this table correspond to a filling time of 60 to 400 s. Longer flow times (up to 100 s) may be used.

331

Viscosity Range, pa

42 180 600 2 400 9 600

to to 3 to 12 to 52 to 200

800 200 800 000 000

t~) D 2171 X3.2.3 A viscometer holder can be made by drilling a 28-ram hole through the center of a No. I 1 rubber stopper and slitting the stopper between the hole and the edge. When placed in a 2-in. (5 l-ram) diameter hole in the bath cover, it holds the viscometer in place.

A, and precision-bore glass capillary vacuum tube, M. These two parts are joined by a borosilicate ground glass joint, N, having a 24/40 standard taper. The measuring bulbs B, C, and D, on the glass capillary are 20-mm long capillary segments, separated by timing marks F, G, H, and I.

X4. CALIBRATION OF VISCOMETERS K = viscometer bulb calibration factor, P/s at 300 mm Hg, v = viscosity of viscosity standard at calibration temperature, P, and t = flow time, s. X4.3.1.8 Repeat the calibration procedure using the same viscosity standard or another viscosity standard. Record the average calibration constant, K, for each bulb.

X4.1 Scope X4.1.1 This appendix describes the materials and procedures used for calibrating or checking the calibration of viscometers used in this method. X4.2 Reference Materials X4.2. l Viscosity Standards having approximate viscosities are given in Table X4.1.

NOTE X l - - T h e duplicate determinations of calibration constant, K, for each bulb must agree with 2 % of their mean (Note X2). NOTE X 2 - - T h e bulb constants are independent of temperature.

Calibration X4.3.1 Calibration of Vacuum Viscometer by Means of Viscosity Standards--Calibrate the vacuum viscometer as follows: X4.3.1.1 Select from Table X4.1 a viscosity standard having a minimum flow time of 60 s at the calibration temperature. X4.3.1.2 Charge a clean, dry viscometer by pouring the sample to within +2 mm of fill line E (See Figs. 2, 3, and 4). X4.3.1.3 Place the charged viscometer in the viscometer bath, maintained at the calibration temperature + 0.02*F (_0.0 l°C). x4.3.1.4 Establish a 300 + 0.5-mm Hg vacuum in the vacuum system and connect the vacuum system to the viscometer with the toggle valve or stopcock closed in the line leading to the viscometer. X4.3.1.5 After the viscometer has been in the bath for 30 ___ 5 min, start the flow of standard in the viscometer by opening the stopcock or toggle valve in the line leading to the vacuum system. X4.3.1.6 Measure to within 0.1 s, the time required for 'he leading edge of the meniscus to pass between timing :larks F and G. Using a second timer, also measure to within 0. l s, the time required for the leading edge of the meniscus to pass between timing marks G and H. If the instrument contains additional timing marks, similarly determine the flow time for each successive bulb. X4.3.1.7 Calculate the calibration factor, K, for each bulb as follows: K = v/t

X4.3

X4.3.2 Calibration of Vacuum Viscometer by Means of Standard Vacuum Viscometer--Calibrate the vacuum viscometer as follows: X4.3.2.1 Select any petroleum asphalt having a flow time of at least 60 s. Select also a standard viscometer of known bulb constants. X4.3.2.2 Mount the standard viseometer together with the viscometer to be calibrated in the same bath at 140*F (60"C) and determine the flow times of the asphalt by the procedure described in 8.1. X4.3.2.3 Calculate the constant, K, for each bulb as follows: K, = (t 2 X K2)/t,

where: K~ = constant of viscometer bulb being calibrated, t~ = flow time of viscometer bulb being calibrated, /(2 = bulb constant of standard viscometer, and t2 = flow time of corresponding bulb in standard viscometer. TABLE X4.2

Test Temperature Scale Errora 68 and 70 77 86

lOO 122 130 140 180 200 210 and 212

Viscosity Standards Approximate Viscosity, P

Viscosity N30,000A N190,000A $30,000 A

At 680F (20°C)

Atl00OF (380C)

1500 8000

240 1600 240

...

275

A Available in 1-pt containers. Purchaseorders should be addressed to Cannon Instrument Co., P. O. Box 16, State College, PA 16801. Shipment will he made as specified or by best means.

332

Thermometer Number

*C

ASTM c

20 and 21.1 25 30

44F, C 45F, C 118F, C

29F, C 30F, C

3r6

26F

3i F, C

40 50 54.4 60 82.2 93.3 98.9 and 100 100 135

120C 46F, C 29F 47F, C 48F ... 30F 121C 110F, C

OF

where: TABLE X4.1

Kinematic Viscosity Test ThermometersA Ipo

66F, C 34F, C 35F, C 90F, C 36F, C 32F, C

a The smallest graduation of the Fahrenheit thermometers is 0.1°F and for the Celsius thermometers is 0.05*C. a Scale error for the Fahrenheit thermometers is not to exceed ±0.2*F (except for ASTM 110F which is +0.3*F); for the Celsius thermometers it is ±0.1*C. These scale errors are required to apply only at the given test temperature. c Complete construction detail Is given in Specifications E 1. o Complete construction detail is given in Part I of IP Standards for Petroleum end Its Products.

~@) D 2171 X5. ICE POINT DETERMINATION AND RECALIBRATION OF KINEMATIC VISCOSITY THERMOMETERS X5.1 To achieve an accuracy of _0.02"C for calibrated kinematic viscosity thermometers, it is required that a check at the ice point be made and the corrections altered for the change seen in the ice point. It is recommended that the interval of checking be every six months; for a new thermometer, check monthly for the first six months. X5.2 A detailed procedure for the measurement of the ice point and recalibration of thermometers is described in 6.5 of Test Method E 77. The suggestions in the following sections of this appendix are given specifically for the mercury-in-glass kinematic viscosity thermometers described in Table X4.2, and may not apply to other thermometers. X5.2.1 The ice point reading of kinematic viscosity thermometers shall be taken within 60 min after being at the test temperature for not less than 3 min. The ice point reading shall be expressed to the nearest 0.01*C or 0.02*F. X5.2.2 Select clear pieces of ice, preferably made from distilled or pure water. Discard any cloudy or unsound portions. Rinse the ice with distilled water and shave or crush into small pieces, avoiding direct contact with the hands or any chemically unclean objects. Fill the Dewar vessel with the crushed ice and add sufficient distilled and preferably precooled water to form a slush, but not enough to float the ice. As the ice melts, drain off some of the water and add more crushed ice. Insert the thermometer picking the ice gently about the stem, to a depth approximately one scale division below the 0*C (32"F) graduation. It may be necessary to repack the ice around the thermometer because of melting. X5.2.3 After at least 3 min have elapsed, tap the stem

gently, and observe the reading. Successive readings taken at least 1 min apart should agree within one tenth of a division. X5.2.4 Record the ice point reading and compare it with the previous reading. If the reading is found to be higher or lower than the reading corresponding to a previous calibration, readings at all other temperatures will be correspondingly increased or decreased. X5.2.5 The ice point procedure given in X5.1 through X5.2.4 is used for the recalibration of kinematic viscosity thermometers, and a complete new calibration of the thermometer is not necessary in order to meet the accuracy ascribed to this design thermometer. X5.3 It is recommended that these kinematic viscosity thermometers be stored vertically when not in use so as to avoid the separation of the mercury column. X5.4 It is recommended that these kinematic viscosity thermometers be read to the nearest I/5 of a division using appropriate magnification. Since these thermometers are typically in a kinematic viscosity bath (which has vision through the front), the thermometer is read by lowering the thermometer such that the top of the mercury column is 5 to 15 mm below the surface of the bath liquid. Be careful to ensure that the expansion chamber at the top of the thermometer is above the lid of the constant temperature bath. If the expansion chamber is at elevated or lowered temperatures from ambient temperatures, a significant error can occur. This error can be as much as one or two thermometer divisions. A reading glass such as used for reading books may be useful to ensure reading the scale to I/5 of a division.

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103.

333

~l~

Designation: D 2306 - 96

Standard Test Method for Ca Aromatic Hydrocarbon Analysis by Gas Chromatography 1 This standard is issued under the fixed designation D 2306; the number immediately following the designation indicates the year of original adoption or, in the ease of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (~) indicates an editorial change since the last revision or rcapproval.

D 5060 Test Method for Determining Impurities in HighPurity Ethylbenzene by Gas Chromatography 2 D 5211 Specification for Xylenes for p-Xylene Feedstock2 E 29 Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications~ E 260 Practice for Packed Column Gas Chromatography 5 E 355 Practice for Gas Chromatography Terms and Relationships 5 E 691 Practice for Conducting an Interlaboratory Test Program to Determine the Precision of Test Methods 5 2.2 Other Document: OSHA Regulations, 29 CFR, paragraphs 1910.1000 and 1910.12006

1. Scope 1.1 This test method determines the relative distribution of the individual C a aromatic hydrocarbon isomers in the following xylene products: 1.1. l Nitration grade xylene conforming to Specification D 843. I. 1.2 Xylenes for p-Xylene feedstock conforming to Specification D 521 I. 1.1.3 Ten-degree xylene conforming to Specification D 846. 1.2 The absolute concentration of hydrocarbon impurities typically found in commercially available mixed Cg aromatic hydrocarbons should be determined using Test Method D 2360. !.3 The following applies to all specified limits in this test method: for purposes of determining conformance with this test method, an observed value or a calculated value shall be rounded off "to the nearest unit" in the last right-hand digit used in expressing the specification limit, in accordance with the rounding-off method of ASTM Practiee E 29. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements, see Section 8.

3. Summary of Test Method 3.1 The specimen is introduced into a gas chromatograph equipped with either a flame ionization detector (FID) or thermal conductivity detector (TCD). Either packed or capillary columns are permitted. The peak area of each component is measured and the weight percent concentration is calculated by dividing the peak area of the individual component by the sum of the total individual peak areas. The result is multiplied by 100 to get the normalized Ca aromatic hydrocarbon isomer distribution. 4. Significance and Use 4.1 This test method is suitable for setting specifications on the materials referenced in 1.1.1 through 1.1.3. This test method may also be used as an internal quality control tool and in development or research work. 4.1.1 Refer to Methods D 5060, D 3797, and D 3798 to determine the purity of ethylbenzene, o-xylene, and p-xylene respectively. 4.2 This test method does not attempt to determine the absolute purity of the sample, but defines the relative distribution of the Cg aromatic hydrocarbons.

2. Referenced Documents

2.1 A S T M Standards: D 843 Specification for Nitration Grade Xylene 2 D 846 Specification for Ten-Degree Xylene 3 D 2360 Test Method for Trace Impurities in Monocyclic Aromatic Hydrocarbons by Gas Chromatography 2 D 3437 Practice for Sampling and Handling Liquid Cyclic Products 2 D 3797 Test Method for Analysis of o-Xylene by Gas Chromatography 2 D3798 Test Method for Analysis of p-Xylene by Gas Chromatography 2 D 4626 Practice for Calculation of Gas Chromatographic Response Factors 4

5. Interferences 5.1 If present, nonaromatic hydrocarbons of twelve carbons or greater will be interferences in this analysis. 6. Apparatus 6.1 Gas Chromatograph--Any instrument having a flame ionization detector or a thermal conductivity detector may be used. A flame ionization detector is preferred. 6.2 Columns--Both capillary and packed columns containing a stationary phase of cross-linked polyethylene glycol

t This test method is under the jurisdiction of ASTM Committee D-16 on Aromatic Hydrocarbons and Related Chemicals and is the direct responsibility of Subcommittee DI6.0A on Benzene, Toluene, Xylenes, Cyelohexane, and Their Derivatives. Current edition approved Dec. 10, 1996. Published February 1997. Originally published as D 2306 - 64. Last previous edition D 2306 - 92 ¢1. 2 Annual Book of ASTM Standards, Vol 06.04. 3 Discontinued 1991. See 1990 Annual Book of ASTM Standards, Vol 06.03. 4 Annual Book of ASTM Standards, Vol 05.02.

s Annual Book of ASTM Standards, Vol 14.02. e Available from the Superintendent of Documents, U.S. Government Printing Office, Washington, DC 20402.

334

o 2ao6 TABLE 1

TABLE 2

Instrumental Parameters Column A

Detector Column: Tub=ng Stationary phase Film thtckness, H Length, m Inside diameter, mm Temperatures: Injector, °C Detector, °C

flame ionization fused silica polyethylene glycol 0,25 50 0.25 200 250

Component

Ethylbenzene

p-Xyiene m-Xylene o-Xylene

Intermediate Precision (formerly called Repeatability) and Reproducibility Expected

Concentration

Average

Concentration

Reported

Intermediate Precision (formerly called

Weight %

Weight %

Repeatability

17.93 20.16 44.09 17.83

17.92 20.07 43.96 17.98

0,077 0.073 0.101 0 116

Reproduc-

ibility 0.153 0.193 0,369 0 193

Oven: Initial, *C Time 1, rain Final, °C Rate, °C/rain Time 2, rain Carrier gas Unear Vel., cm/s Split ratio Sample size, I~L Analysis time, rain

70 10 120 5 0 helium 20 100:1 1.0 20

have been found satisfactory. The column and instrumental conditions described in Table 1 are recommended. 6.3 Recorder--Electronic integration is recommended. 7. Reagents

7.1 Carrier Gas--Chromatographic grade hydrogen, helium or nitrogen have been found acceptable. 8. Hazards 8.1 Consult current OSHA regulations, supplier's Material Safety Data Sheets, and local regulations for all materials listed in this test method. 9. Sampling 9.1 Sample the material in accordance with Practice D 3437. 10. Preparation of Apparatus 10.1 The method used to prepare packed columns is not critical provided that the finished column produces the desired separation. 10.2 Follow manufacturer's instructions for mounting and conditioning the column into the chromatograph and adjusting the instrument to the conditions described in Table 1. Allow sufficient time for the equipment to reach equilibrium. See Practices E 260 and E 355 for additional information on gas chromatography practices and terminology. 10.3 The column must be capable of resolving the Cs aromatic hydrocarbons as individual isomers. 10.3.1 The resolution of two components is defined as follows: 2(tn,~ - tn,p) R=

10.4 For p-xylene and m-xylene, the minimal allowable resolution is 1.0. If the resolution between p-xylene and m-xylene is <1.0, the chromatographic system must be modified to improve the separation. 11. Procedure 11.1 Inject the desired volume of specimen into the gas chromatograph and record the peaks on the sensitivity setting that allows the maximum peak height and minimum baseline noise. The injection volume should be small enough to produce symmetrical gaussian shaped peaks. Fig. I illustrates a typical analysis. 12. Calculations 12.1 Determine the area defined by each peak. 12.1.1 In the event that a thermal conductivity detector is used for the analysis, the observed peak areas may need to be adjusted using response factors. See Practice D 4626 for a discussion on response factors. 12.2 Calculate the weight percent concentration of each Cs aromatic hydrocarbon as follows: (AO(IO0) C i = ~

(A,)

where: Ci = concentration of component i, Ai = peak area of component i, and As - peak area of all C8 aromatic isomers. 13. Report 13.1 Report the individual Cs aromatic hydrocarbons to the nearest 0.01 weight %. 14. Precision and Bias 7 14.1 The following criteria should be used to judge acceptability (95 % probability level) of results obtained by this test method. The criteria were derived from an interlaboratory test amongst 10 laboratories. The data were run on 2 days using different operators using a sample that was gravimetrically prepared from the individual Cs aromatic hydrocarbons to the concentrations listed in Table 2. Fused silica capillary columns containing a polyethylene glycol stationary phase were used by 9/10 laboratories. Flame ionization detection was used by all 10 laboratories. The results of the round robin were analyzed in accordance with Practice E 691.

(wl,,,. + wt,.p)

where: IR. m

• IR,p

R = peak resolution, tn,m = retention time of m-xylene, (m = m-xylene), tn,p -- retention time ofp-xylene, (p = p-xylene), wb,m = peak width at baseline for m-xylene, and Wo,p = peak width at baseline for p-xylene.

v Supporting data are available from ASTM Headquarters. Request RR: DI6-1015.

335

o 23o6 -j

I,IX 990

i E-.BE~ 9.2~

PX 9.56 OX 11.87

z

fi "t

i

1 1

TOL 6.40 ,

6.0

,

Ilql 11.27

~.r-T-V-~--r--r- T r-r--v-.r--r-~--r-r-~.,

6.0

FIG. 1

7.0

e.o

~r"-y'-~r--',r - ---l- ~--r-l-T'--t---r-

g.o

t0.0

t~.o

IN3EB 13.67 "r'-r-l'-v

~a.e

-"~ • r-" r - q ' l r - - r - r - - ' r -1"-- v - r - ' r - T - ' ]

~3.o

s4.0

s6.o

Chromatogrem of Mixed Xylenes Using Conditions for Column A, Table 1

14.2 Bias--Although the interlaboratory test utilized a sample prepared gravimetrically from individual C8 isomers obtained at the highest purity available, this sample has not been approved as an acceptable reference material and consequently bias has not been determined. 14.2.1 As an aid for the users in determining the possibility of bias, calculated C8 distributed for the round robin sample is listed in Table 2 as the "Expected Concentration." The average value for each Cs isomer as calculated from the reported concentrations is listed as "Average Concentration Reported."

14.1.1 IntermediatePrecision (formerly calledRepeatability)--Results in the same laboratory should not be considered suspect unless they differ by more than the amount for repeatability shown in Table 2. On the basis of test error alone, the difference between two test results obtained in the same laboratory on the same material will be expected to exceed this value only about 5 % of the time. 14.1.2 Reproducibility--Results submitted by each of two laboratories should not be considered suspect unless they differ by more than the amount shown for reproducibility in Table 2. On the basis of test error alone, the difference between two test results obtained in different laboratories on the same material will be expected to exceed this value only about 5 % of the time.

15. K e y w o r f l s 15.1 aromatic hydrocarbon; aromatic hydrocarbon analysis; Cs; gas chromatography; isomer; p-Xylene; xylene

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard Is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reepproved or withdrawn. Your comments are Invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which yOu may attend, ff you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 100 Barr Harbor Drive, West Conehohocken, PA 19428.

336

(~l~ Designati°n: D 2360 - 95~1 Standard Test Method for Trace Impurities in Monocyclic Aromatic Hydrocarbons by Gas Chromatography I This standard is issued under the fLxed designation D 2360; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (~) indicates an editorial change since the last revision or rcapproval.

This test method has been approved for use by agencies of the Department of Defense. Consult for listing in the DoD Index of Specifications and Standards for the specific year of issue that has been adopted by the Department of Defense. e~ NotE--Research report was added editorially in March 1996.

1. Scope 1.1 This test method covers the determination of the total nonaromatic hydrocarbons, and trace monocyclic aromatic hydrocarbons in the purity of toluene and mixed xylenes by gas chromatography. 1.2 Nonaromatie aliphatic hydrocarbons containing 1 through 10 carbon atoms (methane through decanes) can be detected by this test method at concentrations ranging from 10 mg/kg to 2.500 weight %. 1.2.1 A small amount of benzene in mixed xylenes may not be distinguished from the nonaromatics and the concentrations are determined as a composite. 1.3 Monocyclic aromatic hydrocarbon impurities containing 6 through 9 carbon atoms (benzene through C9 aromatics) can be detected by this test method at individual concentrations ranging from 10 mg/kg to 1.000 weight %. 1.4 The following applies to all specified limits in this standard: for purposes of determining conformance with this standard, an observed value or a calculated value shall be rounded off "to the nearest unit" in the last right-hand digit used in expressing the specification limit, in accordance with the rounding-off method of Practice E 29. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statement, see Section 8.

D 3797 Test Method for Analysis of o-Xylene by Gas Chromatography 2 D3798 Test Method for Analysis of p-Xylene by Gas Chromatography 2 D4492 Test Method for Analysis of Benzene by Gas Chromatography 2 D5211 Specification for Xylenes for p-Xylene Feedstock2 E 29 Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications3 E 260 Practice for Packed Column Gas Chromatography 3 E 355 Practice for Gas Chromatography Terms and Relationships 3 E 691 Practice for Conducting an Interlaboratory Test Program to Determine the Precision of Test Methods 3 E 15 l0 Practice for Installing Fused Silica Open Tubular Capillary Columns in Gas Chromatographs 3 2.2 Other Document: OSHA Regulations, 29 CFR, paragraphs 1910.1000 and 1910.12004 3. Summary of Test Method 3.1 A known amount of an internal standard is added to the specimen that is then introduced into a gas chromatograph (C-C) equipped with a flame ionization detector (FID). The peak area of each impurity and the internal standard is measured and the amount of each impurity is calculated from the ratio of the peak area of the internal standard versus the peak area of the impurity. Purity by GC is calculated by subtracting the sum of the impurities found from 100.00. Results are reported either in weight percent or volume percent.

2. Referenced Documents

2.1 A S T M Standards: D 841 Specification for Nitration Grade Toluene 2 D 2306 Test Method for Cs Hydrocarbon Analysis by Gas Chromatography 2 D 3437 Practice for Sampling and Handling Liquid Cyclic Products 2

4. Significance and Use 4.1 The determination of hydrocarbon impurities contained in toluene and mixed xylenes used as chemical intermediates and solvents is typically required. This test is suitable for setting specifications and for use as an internal quality control tool where aromatic monocyclic hydrocarbons are produced or are used. This test method is applicable for determining the impurities from the aromatic hydro-

t This test method is under the jurisdiction of ASTM Committee I)-16 on Aromatic Hydrocarbons and Related Chemicals and is the direct responsibility of Subcommittee DI6.0A on Benzene, Toluene, Xylenes, Cyclohexane, and Their Derivatives. Current edition approved April 15, 1995. Published June 1995. Originally published as D 2360 - 66 T. Last previous edition D 2360 - 82 ( 19S7)eL 2 Annual Book of ASTM Standards, Vol 06.04.

3 Annual Book of ASTM Standards, Vol 14.02. 4 Available from Superintendent of Documents, U.S. Government Printing Office, Wnshington DC 20402.

337

~[~ D 2360 carbon production process. Typical impurities are alkanes containing 1 to 10 carbon atoms, benzene, toluene, ethylbenzene (EB), xylenes, and aromatic hydrocarbons containing nine carbon atoms. 4.1.1 Refer to Test Methods D 3797, D 3798, and D 4492 for determining the purity of o-Xylene, p-Xylene, and benzene, respectively. 4.1.2 Refer to Test Method D 2306 for determining the C s aromatic hydrocarbon distribution in mixed xylenes. 4.2 Purity is commonly reported by subtracting the determined expected impurities from 100.00. However, a gas chromatographic analysis cannot determine absolute purity if unknown or undetected components are contained within the material being examined. 5. Interferences 5.1 The internal standard chosen must be satisfactorily resolved from any impurity and the product peak. A peak will be satisfactorily resolved from a neighboring peak if the distance from the valley to the baseline between the two peaks is not greater than 50 % of the peak height of the smaller of the two peaks. 5.2 In some cases for mixed xylenes, it may be difficult to resolve benzene from the nonaromatic hydrocarbons and therefore the concentrations are determined as a composite. In the event that the benzene concentration must be determined, an alternate method must be selected to ensure an accurate assessment of the benzene concentration.

6. Apparatus 6.1 Gas Chromatograph--Any instrument having a flame ionization detector that can be operated at the conditions given in Table 1. The system should have sufficient sensitivity to obtain a minimum peak height response for 10 mg/kg n-butylbenzene of twice the height of the signal to background noise. 6.2 Columns--Both capillary and packed columns containing a stationary phase of cross-linked polyethylene glycol have been found satisfactory. The column must give satisfacTABLE 1 Detector Column: Tubing Stationary phase Film thickness, p Length. m Diameter, mm Temperatures: Injector. "C Detector, "C Oven: Initial, "C Time 1. rnln Final. "C Rate, "C/rain Time 2, mln Carrier gas Flow rate, mL/mln S~t ratio Sample size, pL Analysis time, rain Linear velocity @ 1450C. cm/s

Instrumental Parameters

tory resolution of the internal standard from the solvent and the impurity peaks, and should be such that benzene is eluted between n-nonane and n-decane. Table I contains a description of a column that has been found satisfactory. 6.3 Recorder--Electronic integration is recommended. 6.4 Microsyringe, 10 and 50, and 500-ttL capacity. 6.5 VolumetricFlask, 50-mL capacity.

7. Reagents 7.1 Purity of Reagent--Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, where such specifications are available. 5 7.2 Carrier GasmChromatograpldc grade helium is recommended. 7.3 High Purity p-Xylene, 99.999 weight % or greater purity. 7.3.1 Most p-xylene is available commercially at a purity less than 99.9 % and can be purified by recrystaUization. To prepare 1.9 L of high purity p-xylene, begin with approximately 3.8 L of material and cool in an explosion-proof freezer at - 1 0 :t: -5°C until approximately I/2 to 3/4 of the p-xylene has frozen. This should require about 5 h. Remove the sample and decant the liquid portion. The solid portion is the purified p-xylene. Allow the p-xylene to thaw and repeat the crystallization step on the remaining sample until the p-xylene is free of contamination as indicated by gas chromatography. 7.4 Pure Compounds, for calibration, shall include nnonane, benzene, toluene, ethylbenzene (EB), o-xylene and cumene. The purity of all reagents should be >99 weight %. If the purity is less than 99 %, the concentration and identification of impurities must be known so that the composition of the standard can be adjusted for the presence of the impurities. 7.4.1 Internal Standard--n-butylbenzene (NBB) is the recommended internal standard of choice, however, other compounds may be found acceptable provided they meet the criteria as defined in Section 5.

8. Hazards

Flame Ionization

8.1 Consult current OSHA regulations, supplier's Material Safety Data Sheets, and local regulations for all materials used in this test method.

fused snica orossllnked polyethylene glycol ~ 0.25 60 0.32 IO

9. Sampling

270 300

9.1 Sample the material in accordance with Practice D 3437.

60 10 150 5 10 helium 1.0 100:1 1.0 30 20

I0. Preparation of Apparatus I0.I Follow manufacturer's instructions for mounting and conditioning the column into the chromatograph and adjusting the instrument to the conditions described in Table s Reagent Chemicals, American Chemical Society Spec(licmions, American Chemical Society, Washington, DC. For suuestiom on the testing of reai~nts not listed by the American Chemical Society, tee Analar Standardf for Laboratory Chemicals, BDH Ltd., Peele, Donet, U.IC, and the United States Pharmacopeia and National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), RoekviUe, MD.

Polyethylene glycol such as Carbowax 20 m avaUablefrom Union Carbine Chemical Co., or most chromatographic suppliers, has been fou~l suitable for this purpose.

338

~)

D 2360

1 allowing sufficient time for the equipment to reach equilibrum. See Practices E 260 and E 355 and E 1510 for additional information on gas chromatography practices and terminology. 11. Calibration 11.1 Prepare a synthetic mixture of high purity p-xylene with representative impurities. The volume of each hydrocarbon impurity must be measured to the nearest 0.1 ~tL and all liquid reference compounds must be brought to the same temperature before mixing. Refer to Table 2 for an example of a calibration blend. The nonaromatic fraction is represented by n-nonane, while o-xylene represents the xylene fraction. Cumene will represent the aromatic hydrocarbons containing nine carbon atoms or greater (C9 aromatics). 11.2 Using the exact volumes and densities in Table 2, calculate the weight percent concentration for each impurity in the calibration blend as follows: C i = ((Di)(V,))/(( VpXDo)XI00) (I) where: D i = density of impurity i from Table 2, V; = volume of impurity i, mLs, Dp = density ofp-xylene from Table 2, Vp - volume ofp-xylene, mLs, and C; = concentration of impurity i, weight percent. 11.3 Into a 50-mL volumetric flask, add 50.0 gL of n-butylbenzene (NBB) to 50.00 mLs of the calibration blend and mix well. Assuming a density of 0.857 for the calibration blend and 0.856 for NBB, the resulting NBB concentration will be 0.100 weight %, as determined from the equation in 11.2. 11.3.1 All solutions and reference compounds must be brought to the same temperature, preferably 25"C, prior to adding the internal standard. 11.4 Inject the resulting solution from 11.3 into the chromatograph. A typical chromatogram is illustrated in Fig. 1. 11.5 Determine the response factor for each impurity relative to NBB by measuring the area under each peak and calculate the relative response factor as follows:

(a,)(q) (c, xA,)

RRF i = ~

"

m

~x

]

Z

I!'

Z

L .

.

.

.

.

.

.

.

Oo

i:

.

.

.

I ft.00

.

.

.

.

.

.

.

.

.

.

.

I 10.00 FIG. 1

I

,, J,,L_iJ._ I 1fi.O0

I

L I 20.00

Typical ~ a l y s i s of Calibration Standard

Cs

= concentration of the internal standard, NBB, weight percent, and Ci -- concentration of impurity i, as calculated in 11.2, weight percent. 11.6 Calculate the response factors to the nearest 0.001.

12. Procedure 12.1 Bring the internal standard and the sample to be analyzed to identical temperatures, preferably 25°C. Make sure that the temperature of the sample is consistent with that of the calibration standard prepared in Section 11. Pipet 50.0 ttL of internal standard into a 50-mL volumetric flask containing 50.00 mLs of sample. Mix well. 12.2 Depending upon the actual chromatograph's operating conditions, inject an appropriate amount of sample into the instrument. Make sure that the injection amount is consistent with those conditions used to meet the criteria in 6.1.

(2)

where: RRF~ = response factor for impurity i relative to the internal standard, Ai = peak area of impurity, i, As = peak area of the internal standard, NBB, V TABLE 2

Preparation of Calibration Blend

=

Resulting Concentration Compound

DensityA

Recommended Volume ( p L )

p-Xylene (see 7.3.1) Benzene Toluene Ethylbenzene o-Xylene Cumene n-Nonene

0.857 0.874 0.862 0.863 0.876 0.857 0.714

50.00 mL 10.0 10.0 50.0 50.0 10.0 10.0

Volume Percent 99.72 0.020 0.020 0.100 0.100 0.020 0.020

I

Weight Percent

o

99.72 0.020 0,020 0,101 0.099 0.020 0.017

5.00

T 10.00

T 15.00

T 20.00

MINUTES

A Density at 250C. Values obtained from Physical Constants of Hydrocarbons C1 to Clo, ASTM Publication Data Series 4A, 1971.

FIG. 2 339

Typical Analysis of Specification

D 841 on Toluene

(~

D 2360 TABLE 3

12.3 Measure the area of all peaks except the major component(s). Measurements on the sample must be consistent wth those made on the calibration blend. The nonaromatic fraction includes all peaks up to toluene (except for the peak assigned as benzene). Sum together all the nonaromatic peaks and report as a total area. The C9 aromatics fraction includes cumene and all peaks emerging after o-xylene. Sum together all the C9 aromatic peaks and report as a total area. 12.4 Figure 2 illustrates the analysis of Specification D 841 toluene. Figure 3 illustrates the analysis of Specification D 5211 mixed xylenes.

13. Calculations 13.1 Calculate the weight percent concentration of the total nonaromatics and each impurity as follows:

c, =

(A,)(~F,XC,) (As)

(3)

where: V~. = concentration of impurity i, volume percent, and Di -- density of impurity i from Table 2. 13.3 Calculate the purity of the sample as follows: purity, weight percent = 100.00 - Cs

(5)

! t

o~ eJ

Z

II

5.00

o

I.

m

':

]

~9 AromatJ

I

I

I

10.00

15.00

20.00

0.0110 0.0063 0.0038 0.0040 0.0003 0.0210

Mixed Xyianes

Intermediate Precision

Nonaromatlcs (2.526) Toluene (0.649) Cumene (0.010) Xyia¢~ (98.82)

0.150 0.052 0.0007 0.180

ReproduclblUty 0.816 0.153 0.0013 0.819

16. Keywords 16.1 impurities; purity; toluene; xylenes

MINUTES

FIG. 3

0.0067 0.0041 0.0038 0.0031 0.0003 0.0160

15.1 Precision--The following criteria shoiuld be used to judge the acceptability of the 95 % probablity level of the results obtained by this test method. The criteria was derived from the round-robin between seven different laboratories. The data from five laboratories was used in calculating the precision data for toluene. Two samples were analyzed. Each sample was run twice in two days by two different operators. Results of the interlaboratory study were calculated and analyzed using Practice E 691. 15.1.2 The numbers in parentheses shown in the left hand column of Table 3 are reported average concentrations of the impurities. 15.2 Intermediate Precision, (formerly called Repeatabil. ity)--Duplicate results by the same operator should not be considered suspect unless they differ by more than + the amount shown in Table 3. All values are in weight percent. 15.3 Reproducibility---The results between two laboratories should not be considered suspect unless they differ by more than + the amount shown in Table 3. All values are in weight percent. 15.4 Bias--Since there was no accepted reference material available at the time of interlaboratory testing, no statement on bias can be made at this time. All values are in weight percent.

where: Ct = total concentration of all impurities, weight percent.

°

Reprodudl~lity

Nonaromatics(0.023) Ethylbenzene(0.017) p-Xyiane (0.010) m.Xyiane (0.012) o-Xyiane(0.001) Toluene(99.94)

15. Precision and Bias 6

(4)

% = (C,)/(D,)

Intermediate Precision

14. Report 14.1 Report the following information: 14.1.1 Individual impurities to the nearest 0.001%. 14.1.2 Concentrations of impurities less than 0.001%, report as <0.001%, and consider as 0.000 in summation of impurities, 14.1.3 Total impurities to the nearest 0.01%, and 14.1.4 Purity as "purity (by GC)" to the nearest 0.01%.

13.2 Calculate the volume concentration of the total nonaromatics, total C9 aromatics and each trace aromatic as follows:

V,

Repeatability and Reproducibility

Toluene

e Supportin8 data are available from ASTM Headquerte~. Request RR: D16-I020.

Typical Analysis of Specification D 5211 for Xylenes

340

~) D 2360 The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted In connection with any item mentioned In this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of Infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and ff not revised, either reepproved or withdrawn. Your comments are Invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful coP•ldaratlon at a meeting of the responsible technical committee, which you may attend, ff you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 100 Barr Harbor Drive, West Conshohucken, PA 19428.

341

~I~

Designation: D 2386 - 97

An American NaUonalStandard

Standard Test Method for Freezing Point of Aviation Fuels 1 This standard is issued under the fixed designation D 2386; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (~) indicates an editorial change since the last revision or reapproval.

This test method has been approved by the sponsoring committees and accepted by the Cooperating Societies in accordance with established procedures. This standard has been approvedfor use by agencies of the Department of Defense. Consult the DoD Index of SpecO~cations and Standards for the specific year of issue which has been adopted by the Department of Defense.

1. Scope 1.1 This test method covers the determination of the temperature below which solid hydrocarbon crystals may form in aviation turbine fuels and aviation gasoline. N o t e l - - T h e interlaboratory program that generated the precisions for this test method did not include aviation gasoline.

1.2 The values stated in acceptable metric units are to be regarded as the standard. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements see Notes 2 and 4 through 8.

2. Referenced Documents 2.1 A S T M Standards: D 910 Specification for Aviation Gasolines2 D 1655 Specification for Aviation Turbine Fuels2 D 3117 Test Method for Wax Appearance Point of Distillate Fuels3 D 4305 Test Method for Filter Flow of Aviation Fuels at Low Temperatures 3 E 1 Specification for ASTM Thermometers 4 E 77 Test Method for Inspection and Verification of Thermometers 4 2.2 IP Standard: IP Standards for Petroleum and Its Products, Part 15 3. Terminology 3.1 Definition of Term Specific to This Standard: 3.1.1 freezing point--the fuel temperature at which solid hydrocarbon crystals, formed on cooling, disappear when the temperature of the fuel is allowed to rise. t This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee 1302.07 on Flow Properties. Current edition approved Jan. 10, 1997. Published October 1997. Originally published as D 2386 - 65 T. Last previous edition D 2386 - 88. 2 Annual Book of ASTM Standards, Vo105.01. 3 Annual Book of ASTM Standards, Vol 05.02. 4 Annual Book of ASTM Standards, Vol 14.03. s Available from: Institute of Petrolenm~ 61 New Cavendish Street, London, WIM BAR, U.K.

342

4. Significance and Use 4.1 The freezing point of an aviation fuel is the lowest temperature at which the fuel remains free of solid hydrocarbon crystals that can restrict the flow of fuel through filters if present in the fuel system of the aircraft. The temperature of the fuel in the aircraft tank normally falls during flight depending on aircraft speed, altitude, and flight duration. The freezing point of the fuel must always be lower than the minimum operational tank temperature. 4.2 Freezing point is a requirement in Specifications D 910 and D 1655. 5. Apparatus 5.1 Jacketed Sample TubemA double-walled, unsilvered vessel, similar to a Dewar flask, the space between the sample tube and the outer glass jacket being filled at atmospheric pressure with dry nitrogen or air. The mouth of the tube shall be closed with a cork stopper supporting the thermometer and moisture proof collar through which the stirrer passes (Fig. 1). 5.2 Collars~Moistureproof collars as shown in Fig. 2 may be used instead of the above gland to prevent condensation of moisture. 5.3 Stirrer--Shall be made of 1.6-mm brass rod bent into a smooth three-loop spiral at the bottom. NOTE l - - T h e stirrer may be mechanically actuated as described in

the apparatus section of Test Method D 3117. 5.4 Vacuum Flask--An unsilvered vacuum flask (see Note 2) having the minimum dimensions shown in Fig. 1 shall be used to hold an adequate volume of cooling liquid and permit the necessary depth of immersion of the jacketed sample tube. NOTE 2: Warnin--Implosion hazard. 5.5 Thermometer--A total immersion type, having a range from - 8 0 to +20°C, designated as ASTM No. 114C/IP No. 14C. (See Specification E 1, or Appendix A, IP Standard Thermometers, Volume 2, IP Standard Methods for Analysis and Testing of Petroleum and Related Products.) NOTE 3--The accuracy of this thermometer is to be checked in accordance with Method E 77, at temperatures of 0, -40, -60, and -75"C. 6

6 The U.S. National Bureau of Standards, Oaithersburg, MD, and the British National Physical Laboratory, Teddington, England are able to certify thermometers at these temperature~

~

D 2386

Stirring Rod hermometer

Moisture

Collar

Cork Stopper Sample Tube

l --V 28O 10-15 15-20

235

......

7. Procedure 7.1 Measure out 25 + 1 m L of the fuel and transfer it to the clean, dry, jacketed sample tube. Close the tube tightly with the cork holding the stirrer, thermometer, and moisture proof collar and adjust the thermometer position so that its bulb does not touch the walls of the tube flask and is approximately in the center. The bulb of the thermometer should be I 0 to 15 m m from the bottom oRhe sample tube. 7.2 Clamp the jacketed sample tube so that it extends as far as possible into the vacuum flask (see Note 2) containing the cooling medium (Note 9). The surface of the sample should be approximately 15 to 20 m m below the level of the coolant. Unless the medium is cooled by mechanical refrigeration, add solid carbon dioxide as necessary throughout the test to maintain the coolant level in the vacuum flask. NoTe 9--Acetone and either methyl, ethyl, or isopropyl alcohols are suitable. All of these require cautious handling. Liquid nitrogen may also be used as a coolant instead of liquids cooled with solid carbon dioxide for fuel samples which have a freezing point below -65"C. Mechanical refrigeration is permitted. Where used the refrigerant temperature should be -70"C to 80"C. 7.3 Stir the fuel continuously, moving the stirrer up and down at the rate of 1 to 1.5 cycles/s, except when making observations, taking care that the stirrer loops approach the bottom of the flask on the downstroke and remain below the fuel surface on the upstroke (Note 10). Disregard any cloud that appears at approximately -10*C and does not increase in intensity as the temperature is lowered, because this is due to water. Record the temperature at which crystals o f hydrocarbon crystals appear. Remove the jacketed sample tube from the coolant and allow the sample to warm, stirring it continuously at 1 to 1.5 cycles/s. Record the temperature at which the hydrocarbon crystals completely disappear.

::i:i

Carbon Dioxide Refrigerant Vacuturl Flask NOTE~AIIdimensionsare In mm and +0,1 mm glass wall thickness Is 1 mm. FIG. 1 Freezing Point Apparatus 6. Reagents and Materials 6.1 Acetone (see Note 4) Technical Grade acetone is suitable for the cooling bath, provided it does not leave a residue on drying.

NoTe 10--Because the gases released by the coolant can obscure vision, the sample tube can be removed to observethe appearance of the wax crystals. The tube can be removed for periods no longer than 10 s. If crystalshave already formed, the temperature should be noted and the sample allowed to be reheated to 5"C above the point where the crystals disappear. The sample should then be reimmersed and allowed to cool. Remove the sample slightly above the noted temperature and observe the wax appearance point.

NOTE 4: Warning--Extremely flammable. 6.2 Ethanol or Ethyl Alcohol (see Note 4)--A commercial or technical grade of dry ethanol is suitable for the cooling bath. 6.3 Isopropyl Alcohol (see Note 4 ) w A commercial or technical grade of dry isopropyl alcohol is suitable. 6.4 Methanol or Methyl Alcohol (see Notes 4 and 5)--A commercial or technical grade of dry methanol is suitable for the cooling bath.

8. Report

8.1 The observed freezing point determined in Section 7 shall be corrected by applying the relevant thermometer correction resulting from the checks described in Note 3. Where the observed freezing point falls between two calibration temperatures, the correction at the observed temperature shall be obtained by linear interpolation. Report the corrected temperature of crystal disappearance to the nearest 0.5"C as the freezing point, Test Method D 2386.

NOTE 5: Warning--Toxic. 6.5 Carbon Dioxide (Solid) or Dry Ice (see Notes 6 and 8)--A commercial grade o f dry ice is suitable for use in the cooling bath.

NOTe I l--When results are desired in degreesFahrenheit, test results obtained in degrees Celcius should be converted to the nearest whole degree Fahrenheit. Interim Celcius freezingpoints should carry the best precision available for subsequent conversion to degrees Fahrenheit.

NOTE 6: Warnlno--Extremely cold,-78"(2. 6.6 Liquid Nitrogen (see Notes 7 and 8)--A commercial or technical grade of liquid nitrogen is suitable for the cooling bath when the freezing point is lower than -65"C.

9. Precision and Bias 7

9.1 Precision--The precision of this test method was

NOTe 7: Warning--Extremely cold, -196"C NOTE 8 ~ b o n dioxide (solid) and liquid nitrogen liberate gasses that can cause suffocation. Contact with skin causes burns, freezing, or both. 343

7 The results of a round-robin program from which these values have been derived, are filedat A S T M Headquarters. Request RR:D02-1175.

~

D 2386

12 mm OD

~

NOTE: Top may be covered to -- prevent loss of silica gel

/

12 mm OD

Glass w <-- 25.0 - ~

I ' ',l/

Dehydrating Agent (Silica Gel) o

5 mm OD

o

~

5 mm OD Stirring Rod

Type A NiVogen Collar

Type B Modified Moistureproof Collar

NOTE--All dimensions are in mm and ¢0.1 mm glass wall thickness Is 1 mm. FIG. 2 Moistureproof Collars for Freezing Point Apparatus

working in different laboratories on identical test material would, in the long run, in the normal and correct operation of the test method, exceed 2.3"C only in one ease in twenty. 9.2 B/as--Because there are no liquid hydrocarbon mixtures of "known" freezing point, which simulate aviation fuels, bias cannot be established.

obtained by the statistical examination of the results of 14 samples of fuel consisting of Jet A, Jet A 1, Jet B, JP.4, and JP-5 tested by 16 laboratories. 9.1.1 Repeatability---The difference between two test resuits obtained by the same operator with the same apparatus under constant operating conditions on identical test material would, in the long run, in the normal and correct operation of the test method, exceed 0.8"C only in one case in twenty. 9.1.2 Reproducibility---The difference between two single and independent results obtained by different operators

10. Keywords 10.1 aviation gasoline; aviation turbine fuels; cry~all/7adon point; determination; freezing point; low temperature tests; manual method; petroleum products; physical tests

344

~

D 2386

II

I I I I IAI WOOL PACKING

LENGTH 50 OO i2 LENGTH OD 5

55

DEHYDRATING AGENT

LENGTH 50 OD 5

C NOTE--All dimensions are in mUlimetres. This collar of borosilicate glass is packed with No 12-mesh dehydrating agent at the lower part up to 5 mm of B. Then, with the stirrer in place, a collar of glass wool impregnated with the same size dehydrating agent is pressed snugly over the joint up to A. The glass wool packing should be replaced after every third or fourth run. FIG. 3 M o i s t u r e p r o o f Collar, Type B

The American Society for Testing and Materials takes no position respecting the validity of any patent rights sesarted in oonnection with any item mentioned In this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, end the risk of Infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five yeanl and ff not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical cornmlttea, which you may attend, ff you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 100 Barr Harbor Drive, West Conshohocken, PA 19428.

345

~[~

Designation: D 2 4 2 5 - 93

An American National Standard

Standard Test Method for Hydrocarbon Types in Middle Distillates by Mass Spectrometry 1 This standard is issued under the fixed designation D 2425; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (4) indicates an editorial change since the last revision or reapproval.

1. Scope 1.1 This test method covers an analytical scheme using the mass spectrometer to determine the hydrocarbon types present in virgin middle distillates 204 to 343"C (400 to 650"F) boiling range, 5 to 95 volume % as determined by Method D 86. Samples with average carbon number value of paraffins between CI2 and C1~ and containing paraffins from Cjo and C~s can be analyzed. Eleven hydrocarbon types are determined. These include: paraffins, noncondensed cycloparaffins, condensed dicycloparaffins, condensed tricycloparaffins, alkylbenzenes, indans or tetralins, or both, C~H2~.lo (indenes, etc.), naphthalenes, CnH2n.14 (acenaphthenes, etc.), C,H2,.t6 (acenaphthylenes, etc.), and tricyclic aromatics. NOTE l - - T h i s test method was developed on consolidated Electro-

dynamics Corp. Type 103 Mass Spectrometers. 1.2 The values stated in SI units are to be regarded as the standard. The inch-pound units given in parentheses are for information only. 1.3 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For a specific hazard statement, see 10.1. 2. Referenced Documents

2.1 ASTM Standards: D 86 Test Method for Distillation of Petroleum Products 2 D2549 Test Method for Separation of Representative Aromatics and Nonaromatics Fractions of High-Boiling Oils by Elution Chromatography 2 3. Terminology 3.1 Descriptions of Terms Specific to This Standard; 3.1.1 The summation of characteristic mass fragments are defined as follows: 3.2 Z71 (paraffins) = total peak height of m/e + 71 _-4-85. 3.3 2;67 (mono or noncondensed polycycloparaffins, or both) = total peak height ofm/e + 67 + 68 + 69 + 81 + 82 + 83 + 96 + 97. 3.4 2;123 (condensed dicycloparaffins) = total peak height ofm/e + 123 + 124 + 137 + 138 + . . . etc. u p t o 249 + 250.

3.5 Z149 (condensed tricycloparaffins) = total peak height ofm/e + 149 + 150 + 163 + 164 + . . . etc. up to 247 + 248. 3.6 Y~91(alkyl benzenes) -- total peak height of m/e + 91 + 92 + 105 + 106 + . . . etc. up to 175 + 176. 3.7 ~ 103 (indans or tetralins, or both) = total peak height o f m / e + 103 + 104 + 117 + 118 + . . . etc. up to 187 + 188. 3.8 Z I I 5 (indenes or CnH2n.~O, or both) = total peak height of m/e + 115 + 116 + 129 + 130 + . . . etc. u p t o 185 + 186. 3.9 128 (naphthalene) = total peak height of m/e + 128. 3.10 Z 141 (naphthalenes) = total peak height of m/e + 141 + 142 + 155 + 156 + . . . etc. up to 239 + 240. 3.11 Z153 (acenaphthenes or C,H2,.t4, or both) = total peak height ofm/e + 153 + 154 + 167 + 168 + . . . etc. up to 251 + 252. 3.12 2; 151 (acenaphthylenes or C,H2n.16, or both) = total peak height of m/e + 151 + 152 + 165 + 166 + . . . etc. u p t o 249 + 250. 3.13 Y.177 (tricyclic aromatics) -- total peak height of m/e + 177 + 178 + 191 + 192 + . . . etc. up to 247 + 248.

4. Summaryof Test Method 4.1 Samples are separated into saturate and aromatic fractions by Method D 2549, and each fraction is analyzed by mass spectrometry. The analysis is based on the summation of characteristic mass fragments to determine the concentration of hydrocarbon types. The average carbon numbers of the hydrocarbon types are estimated from spectral data. Calculations are made from calibration data dependent upon the average carbon number of the hydrocarbon types. The results of each fraction are mathematically combined according to their mass fractions as determined by the separation procedure. Results are expressed in mass percent.

NoTE2--Method D 2549, is presently applicable only to samples having 5 % points of 232"C (450"F) or greater. 5. Significanceand Use 5.1 A knowledge of the hydrocarbon composition of process streams and petroleum products boiling within the range of 400 to 650"F (204 to 343"C) is useful in following the effect of changes in process variables, diagnosing the source of plant upsets, and in evaluating the effect of changes in composition on product performance properties.

This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subeommittce 1)02.04 on Hydrocarbon Analyses. Current edition approved Aug. 15, 1993. Published October 1993. Originally published as D 2425 - 65 T. Last previous edition D 2425 - 88. 2 Annual Book of ASTM Standards, Vol 05.01.

6.

Interferences

6.1 Nonhydrocarbon types, such as sulfur and nitrogencontaining compounds, are not included in the matrices for this method. If these nonhydrocarbon types are present to 346

(~

D 2425 69, 71, 81 to 83, 85, 91, 92, 96, 97, 103 to 106, 115 to 120, 128 to 134, 141 to 148, 151 to 162, 165 to 198, 203 to 212, 217 to 226, 231 to 240, 245, 246, 247 to 252. Find: ~71 -- 71 + 85, (1) z67 = 67 + 68 + 81 + 82 + 83 + 96 + 97, (2) ~91 = Y.~.o N'6 [(91 + 14N) + (92 + 14N)], (3) 2;103 = Z~. o m'6 [(103 + 14N) + (104 + 14N)], (4) Zl15=T.1v.oN'5[(II5+ I 4 N ) + ( I I 6 + I4N)], (5) 2;141 = Z~v.o'V-;'[(141 + 14N) + (142 + 14N)], (6) 2;153 = Z2v- o2v" ;' [(153 + 14N) + (154 + 14N)], (7) 2;151=T.N_O~''Z[(151 + 1 4 N ) + ( 1 5 2 + 14N)], (8)

any large extent, (for example, mass percent sulfur > 0.25) they will interfere with the spectral peaks used for the hydrocarbon-type calculation.

7. Apparatus 7.1 Mass Spectrometer--The suitability of the mass spectrometer to be used with this method of analysis shall be proven by performance tests described herein. 7.2 Sample Inlet System--Any inlet system permitting the introduction of the sample without loss, contamination, or change in composition. To fulfill these requirements it will be necessary to maintain the system at an elevated temperature in the range of 125 to 325"C and to provide an appropriate sampling device. 7.3 Microburet or Constant- Volume Pipet.

and Z177 = Zjv.o N'5 [(177 + 14N) + (178 + 14N)].

(9)

11.2 Calculate the mole fraction at each carbon number of the alkylbenzenes for n = 10 to n = 18 as follows:

8. Calibration 8.1 Calibration coefficients are attached which can be used directly provided: 8.1.1 Repeller settings are adjusted to maximize the m/e + 226 ion of n-hexadecane. 8.1.2 A magnetic field is used that will permit scanning from role+ 40 to 292. 8.1.3 An ionization voltage of 70 eV and ionizing currents in the range 10 to 70 IxA are used. NOTE 3--The calibration coefficients were obtained for ion source conditions such that the ~;67/Z71 ratio for n-hexadecane was 0.26/1. The cooperative study of this test method indicated an acceptable range for this Z ratio between 0.2/I to 0.30/1. NOTE 4--Users of instruments other than Consolidated Electrodynamics Corp. Type 103 Mass Spectrometers may have to develop their own operating parameters and calibration data.

Ix. = [Pro - P m - t ( K , ) I / K 2 (10) where: ~t, = mole fraction of each alkylbenzene as represented by n which indicates the number of carbons in each molecular species. m --- molecular weight of the alkylbenzene being calculated, m - 1 = molecular weight minus 1, P = polyisotopic mixture peak at m, m - 1, K~ = isotopic correction factor (see Table 1), and K2 = mole sensitivity for n (see Table 1).

NOTE 6--This step of calculation assumes no mass spectral pattern contributions from other hydrocarbon types to the parentand parent-1 peaks of the alkylbenzenes. Selection of the lowest carbon number l0 is based upon the fact that C9 alkylbenzenes boil below 204"C (400*F) and their concentration can be considered negligible.

9. Performance Test 9.1 Generally, mass spectrometers are in continuous operation and should require no additional preparation before analyzing samples. If the spectrometer has been turned on only recently, it will be necessary to check its operation in accordance with this method and instructions of the manufacturer to ensure stability before proceeding. 9.2 Mass Spectral Background--Samples in the carbon number range C~o to C,s should p u m p out so that less than 0.1% of the two largest peaks remain. For example, background peaks from a saturate fraction at m/e + 69 and 71 should be reduced to less than 0.1% of the corresponding peaks in the mixture spectrum after a normal p u m p out time of 2 to 5 min.

l l . 3 Find the average carbon number of alkylbenzenes, A, in the aromatic fraction as follows:

A -- (Z.=,o"'tSn x V..)/(Z..lo"=ls#.)

the

(1 1)

11.4 Calculate the mole fraction at each carbon number of the naphthalenes for n = 11 to n = 18 as follows: TABLE 1

10. Mass Spectrometric Procedure 10.1 Obtaining the Mass Spectrum for Each Chromatographic Fraction--Using a microburet or constant-volume pipet, introduce sufficient sample through the inlet sample to give a pressure of 2 to 4 Pa (15 to 30 mtorr) in the inlet reservoir. (Warning--See Note 5.) Record the mass spectrum of the sample from m/e + 40 to 292 using the instrument conditions outlined in 8.1.1 through 8.1.3. NOTE 5: WarningJHydrocarbon samples of this boiling range are combustible.

Parent Ion Isotope Factors and Mole Sensitivities

Carbon No.

m/e

Isotope Factor, K1

Mole Sensitivity, K2

Alkylbenzenes 10 11 12 13 14 15 16 17 18

134 148 162 176 190 204 218 232 246

0.1101 0.1212 0.1323 0,1434 0.1545 0,1556 0,1767 0.1878 0.1989

85 63 60 57 54 51 48 45 42

L,

I-2

0.1201 0.1314 0.1425 0.1536 0.1647 0.1758 0.1871 0.1982

194 166 150 150 150 150 150 150

Naphthalenes 11 12 13 14 15 16 17 18

11. Calculations 11.1 Aromatic FractionmRead peak heights from the record mass spectrum corresponding to m/e + ratios of 67 to 347

142 156 170 184 198 212 226 240

fl~ D 2425 (12) x . = [Pro -- P m . , ( L ) I / L 2 where: -- mole fraction of each naphthalene as represented xn by n which indicates the number of carbons in each molecular species, rn -- molecular weight of the naphthalenes being calculated, m - 1 = molecular weight minus 1, P -- polyisotopic mixture peak at m, m - 1, L~ = isotopic correction factor (see Table 1), and /.2 ffi mole sensitivity for n (see Table 1). NOTE 7--This step of calculation assumes no mass spectral pattern contributionsto the parent and parent-1 peaks of the naphthalenes.The concentrationof naphthalene itselfat a molecularweightof 128 shall be determined separately from the polyisotopic peak at m/e+ 128 in the matrix calculation. The average carbon number for the naphthalenes shall be calculatedfrom carbon number 11 (molecularweight 142)to 18 (molecular weight 240).

11.5 Find the average carbon number of the naphthalenes, B, in the aromatic fraction as follows: B = (Z..,,"arccn)/(~,,,.,l'tSx.) 03) 11.6 Selection of pattern and sensitivity data for matrix carbon number of the types present. The average carbon number of the paraffins and cycloparaffins (Z71 and Z67, respectively) are related to the calculated average carbon of the alkylbenzenes (11.3), as shown in Table 2. Both Z71 and Z67 are included in the aromatic fraction matrix to check on possible overlap in the separation. The other types present, represented by Z's 103, 115, 153, and 151, are usually relatively low in concentration so that their parent ions are affected by other types present. The calculation of their average carbon number is not straight forward. Therefore, their average carbon numbers are estimated by inspection of the aromatic spectrum. Generally, their average carbon numbers may be taken to be equivalent to that of the naphthalenes, or to the closest whole number thereof, as calculated in 11.5. The average carbon number of tricyclic aromatics Z177 has to be at least C14 and in full boiling range middle distillates CI4 may be used to represent the ~177 types carbon number. From the calculated and estimated average carbon numbers of the hydrocarbon types, a matrix for the aromatic fraction is set up using the calibration data given in Table 3. A sample matrix for the aromatic fraction is shown in Table 4. The matrix calculations consist Relationship Between Average Carbon Numbers of Alkylbenzenes, Paraffins, and Cycloparaffins

TABLE 2

Alkylbenzenes

Paraffin and Cycloparaffin

Average Carbon No.

Average Carbon No.

10 11 12 13 14

11 12 13 15 (14.5) 16 (15.5)

348

in solving a set of simultaneous linear equations. The pattern coefficients are listed in Table 3. The constants are the Z values determined from the mass spectrum. Second approximation solutions are of sufficient accuracy. If many analyses are performed using the same type of a matrix, the matrix may be inverted for simpler, more rapid desk calculation. Matrices may also be programmed for automatic computer operations. The results of matrix calculations are converted to mass fractions by dividing by mass sensitivity. The mass fractions are normalized to the mass percent of the aromatic fraction, as determined by the separation procedure. I 1.7 Saturate FractionmRead peak at heights from the record of the mass spectrum corresponding to m/e + ratios of 67 to 69, 71, 81 to 83, 85, 91, 92, 96, 97, 105, 106, 119, 120, 123, 124, 133, 134, 137, 138, 147 to 152, 161 to 166, 175 to 180, 191 to 194, 205 to 208, 219 to 222, 233 to 236, 247 to 250. Find: Z71 = 71 + 85, (14) z67 = 67 + 68 + 69 + 81 + 82 + 83 + 96 + 97, (15) Y-123 = N~v.ojr-9 [(123 + 14N) + (124 + 14N)], (16) Y.149 = ~Jv.oJV- z [(149 + 14N) + (150 + 14N)], (17) 2;91 = Y.~v.oJr-6 [(91 + 14N) + (92 + 14N)]. (18) 11.8 Selection of the pattern and sensitivity data for matrix calculation is dependent upon the average carbon number of the types present. The average carbon number of the paraffins and cycloparaffin types (Z's 71, 69, 123, and 149), are related to the calculated average carbon number of the alkylbenzenes of the aromatic fraction (11.3), as shown in Table 2. The Y~91 is included in the saturate fraction as a check on the efficiency of the separation procedure. The pattern and sensitivity data for the Z91 are based on the calculated or estimated average carbon number from the mass spectra of the aromatic fraction (see 11.3). From the determined average carbon numbers of the hydrocarbon types, a matrix for the saturate fraction is set up using the calibration data given in Table 3. A sample matrix for the saturate fraction is shown in Table 5. The matrix calculations of the saturate fraction consists in solving a set of simultaneous linear equations. The results of the matrix calculations (second approximation solutions are sufficient) are converted to mass fractions by dividing by mass sensitivity. The mass fractions are normalized to the mass percent of the saturate fraction as determined by the separation procedure. 12. Precision and Bias 12.1 The precision of this tes: method as obtained by statistical examination of interlaboratory test results on samples having the composition given in Table 7 is as follows: 12.1.1 Repeatability---The difference between successive test results obtained by the same operator with the same apparatus under constant operating conditions on identical test material, would be in the long run, in the normal and correct operation of the test method, exceed the values shown in Table 6 only in one case in twenty.

(~

TABLE 3 Hydrocarbon Type Carbon N o . . . Peaks read: ~71 ~67 ~123 ¢149 Z92 to 176 Z103 to 188 2;115 ~o 186 ~128 pk 2;141 2;153 Z151 ~177 Sensitivity: Mole Volume Mass

Paraffins 13

14.5

15.5

100 19

100 21

100 23 0.1

100 26 0.2

12

148 66 87

13

14.5

15.5

1.1 130 100 5

4

6

6

2

100 1

100 1

100 1

100 3

160 100 0.2

i'" 1

i'" 5

2 7

2 lO

. . . . . . . . .

2

2

. . . . . . . . .

170 70 92

192 74 97

238 81 104

416 165 204

439 170 209

220 107 122

302 145 180

347 153 191

Alkylbenzenes 11

Sensitivity: Mole Volume Mass

450 265 304

12

. . . .

13

0.3 0.4 0.7 2 0.1 0.2 1 1.5 100 100 10 10 4.5 5 1 1 . . . . . . . . . . . . . . . . . . . . . . . . . .

450 242 278

450 222 256

14 0.5 3 0.3 2 100 9 5 1

10 0.2 0.6

15 to 34A.a 100 20 to 12A,a 3

. . .... .

.

13

14.5

15.5

1.5 150 100 8

1 175 26 100 15 1

1 170 10 100 15 ...

2 150 20 100 20 3

.

.

.

12

0.4 1 0.1

0.4 1 1

1 2 2

01

02

450 206 237

thylenes or C"H='~e

Carbon N o . . .

12

12

13

380 280 288

13

03

.

420 276 288

.

.

420 250 263

.

.

.

10 0.3 0.3 0.4

298 117 134

220 118 124

268 150 158

298 127 135

.

.

.

13 1.7 6.0 4.8

Naphthalenes

10

11

0.5 0.8 0.2

09

17 15 100 100 25 25 7 ... 1.0 2.5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

.

268 137 156

18 100 28 5.4

.

.

Indenes or CnH2n.lo, or Both

11

.

Acsnaphthenes or CnH2~.14' or Both 13

.

Indans or Tetralins, or Both

Hydrocarbon Type

~141 2;153 ~151 ;~177 Sensitivity: Mole Volume Mess

15.5

4

......

0.3 0.7 0.1 1.3 100 9 4.4 0.7 . . . . . . . . . . . .

2;103 to 166 ZllSto186 ~.128 pk

14.5

Condensed Tdcycloparaffins

9'"

Peaks read: Z71 ~67 Z123 Z149 Z91to176 ~103 to 188 ~115 to 166 2;128 pk Z141 Z153 2;151 Z177

Peaks read: 2;71 2;67 Z91 to 176

13

Condensed Dicycloparaffins

0.5

Hydrocarbon Type Carbon No...

Patterns and Sensitivities for Middle Distillates

Noncondensed Cycloparaffins

12

...

D 2425

.

()i(~ 1.5 100 15

.

420 227 241

410 307 315

6.2 20.3 100 13 28 6.1 4.5

()11 0.6 11.4 100 •. . . . . . . . . . . . . .

0,6

.

372 196 200

236 211 184

.

.

.

.

.

12

13

5.2 1.2 0.5

1.5 1.5 7.8

2 2 4

01

07

05

0.9 0.1 23 0.7 100

1

1

0.1 19 5.6 100 8 7

0.1 18 5.6 100 10 7

.

.

360 2590 254

.

.

.

.

380 248 244

380 226 224

AcenaphTricyclic Aromatics 14

1 0.3 0.1

1 2 5

1 1 1

1 5 3

0.6 0.7

0:8 1

3 06 0.7

02 03 0.2

3 27 0.1

8 100 27 ...

10 100 20 4

1 17 100 ...

100 15

1.5 1.0 0.8 0.3 3.5 30 100

330 218 214

330 198 196

340 199 224

340 187 205

365 211 205

"-15"

Characteristic Mass Groupings

16

Peaks Read

~71 = 71, 85 2;67 = 67, 68, 69, 81, 82, 83, 96, 97 :~123 = 123, 134, 137, 138 up to 249, 250 2;149 = 149, 150, 163, 164 up to 247, 248 2;91 = 91, 92, 105, 106 up to 175, 176 2;103 = 103, 104, 117, 118, up to 187, 186 2;115 = 115, 116, 129, 130 up to 185, 186 2;128 = poly 128 pk 2;141 = 141,142, 155, 156 up to 239, 240 Z153 = 153, 154, 167, 168 up to 251,252 ~151 = 151,152, 165, 166 up to 249, 250 2;177 = 177, 178, 191,192 up to 247, 248

A = methyl indans. a tetralins.

349

Hydrocarbon Types

paraffins cycloparaffins, mono or noncondensed cycloparaffins condensed dicycloparaffins condensed tricycloparaffins alkylbenzenes indan or tetrains, or both C.H~.lo (indenes, etc.) naphthalene naphthalenes CnH~-14 (acenaphthenes, etc.) CnH~.le (acenaphthylenes, etc.) tricyclic aromatics

~) D 2425 TABLE 4

Hydrocarbon Type

Paraffins

Cycloparaffins

15.5

15.5

14

13

13

10

100 26 0.4

6 100 3 2 1

1 2 15 100 25 3

10 2

0.5 3 100 9 5 1 . . . . . . . .

1.7 6 6.2 203 100 13 28 6.1 4.5 0.6

439 170 209

450 206 237

372 198 200

236 211 184

Carbon No. . . . Peaks read: 2;71 2;67 2;91 2;103 2;115 2;128 pk 2;141 ¢153 2;151 2;177 Sensitivity: Mole Volume Weight

... ... 12 ... ... ...

238 81 105

Alkylbenzenes

Aromatic Concentration Matrix

013 2

. . . .

Indans and Tetralins

. . . .

. . . .

. . . . 420 227 241

TABLE 5

Indenes

Acenaphthenes CnH2n.14

Acenaphthylanes CnH2n.le

13

13

13

0.5 0.8 0.1 08 11.4 100 ... ...

2 2 1 01 18 5.6 100 10

1 2 5 3 0.8 0.7 10 100

1 5 3 3 2.7 0.1 ... 15

...

7

20 4

100 15

330 198 196

340 187 205

Naphthalene Naphthalenes

. . . . . . 380 226 224

14 0.6 0,7 18 15 1 0.8 0.3 3.5 30 100

365 211 205

Saturate Concentration Matrix

Paraffins

Monocycloparaffins

Dicycloparaffins

Carbon No. . . . . . . . . . . . . . . . .

15.5

15.5

15.5

15.5

14

2;71 2;67 2;123 2;149 2;91 Sensitivity: Mole Volume Weight

100 26 0.2

6 100 3

0.4

3

1.5 150 100 8 5

2 150 20 100 20

0.5 3 0.3 2 100

238 81 105

439 170 209

298 117 134

298 127 135

450 206 237

Hydrocarbon Type

TABLE 6

Compound Saturate Fraction: Paraffins Monocycioparaffins Dicycloparaffins Tdcycioparaffins Alkylbenzenes Aromatic Fraction: Paraffins Cycloparaffins Alkylbenzanes Indan and/or tetralins CnH2n-10 Naphthalenes C,,H2n-14 CnH2n-16 C,,H2n-18

Tdcydic Aromatics

TABLE 7

Precision of M e t h o d

Concentration Mass. ~

Repeatability

Reproducibility

40 to 50 18 to 25 6 to 12 1 to 5 0 to 3

0.5 1.1 0.7 0.3 0.2

4.0 5.2 4.4 2.0 0.3

0 to 2 0 to 2 3 to 8 2 to 5 0 to 4 3 to 8 0 to 3 0 to 3 0 to 3

0.4 0.5 0.3 0.3 0.3 0.3 0.1 0.3 0.1

0.6 0.9 1.4 0.5 0.7 1.0 0.9 0.7 0.4

Component Sample No. 7D: Paraffins Monocycloparaffin Dicyloparaffin Tdcycloparaffin AIkylbenzane Sample No. 8E: Paraffins Cycioparaffin Alkylbenzene tndan and/or tetralin C, H2n-10 Naphthalenes C,H2n-14 CnH2n-16 CnH2n-18

Tdcycloparaffins

Alkyl. benzenes

Composition of S a m p l e s T e s t e d A

Mean. Mass. ~

o,e

o~ c

44.25 22.04 8.54 2.84 0.33

0.16 0.34 0.23 0.11 0.04

1.30 1.70 -1.42 0.64 0.10

0.07 0.75 5.10 3.65 2.05 5.15 2.50 1.65 1.05

0.14 0.15 0.10 0.09 0.08 0.08 0.04 0.10 0.04

0.14 0.25 0.44 0,14

0.20 0.29 0.26 0.18 0.14

A Twelve laboratories cooperated and each sample was run twice, a er = repeatability standard deviation. c OR = reproducibility standard deviation. O Sample No. 7 - saturate fraction of • virgin middle distillate (78.0 wt % of tot=d). E Sample No. 8 = aromatic fraction of a virgin middle distillate (22.0 wt ~ of total).

350

fl~ D 2425 12.1.2 Reproducibility---The difference between two tingle and independent results, obtained by different operatots working in different laboratories on identical test material, would in the long run, in the normal and correct operation of the test method, exceed the values shown in Table 6 only in one ease in twenty.

NOTE 9--The precision for this test method was not obtained in accordance with RR:D02-1007.3 12.2 Bias--Bias cannot be determined because there is no acceptable reference material suitable for determining the bias for this test method. 13. Keywords 13.1 hydrocarbon types; mass spectrometry; middle distillates

NOTE 8--If samples are analyzed that differ appreciably in composition from those used for the interlaboratory study, this precision statement may not apply.

3 Annual Book of ASTM Standards, Vol 05.03. The American Society for Testing and Materials takes no position respact/ng the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and ff not revised, either reepproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at • meeting of the responsible technical committee, which you may attend. If you feel that your comments have not received e fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103.

351

q~]l ~ Designation: D 2426 - 93

~Amerlc~St~darO

Standard Test Method for Butadiene Dimer and Styrene in Butadiene Concentrates by Gas Chromatography I This standard is issued under the fixed designation D 2426; the number immediately following the desisnation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon O) indicates an editorial change since the last revision or re.approval.

1. Scope 1.1 This test method covers the determination of butadiene dimer (4-vinylcyclohexene-l) and styrene in butadiene concentrates, both "recycle" and specification grade. 1.2 The values stated in SI units are to be regarded as the standard. 1.3 This standard does not purport to address all of the

safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific precautionary statements see Notes 1, 2, and 4.

2. Referenced Documents

2.1 ASTM Standards: D 1265 Practice for Sampling Liquefied Petroleum (LP) Gases2 D 1657 Test Method for Density or Relative Density of Light Hydrocarbons by Pressure Thermohydrometer 2 D 1945 Test Method for Analysis of Natural Gas by Gas Chromatography 3 D2593 Test Method for Butadiene Purity and Hydrocarbon Impurities by Gas Chromatography 2 E 260 Practice for Packed Column Gas Chromatography 4

suitable for use in internal quality control and in establishing product specifications.

5. Apparatus 5.1 Chromatograph--Any chromatograph having either a thermal conductivity or flame ionization detector may be used. The detector system shall have sufficient sensitivity to obtain a deflection of at least 2 mm at a signal-to-noise ratio ofat least 5:1 for 0.01 weight % ofbutadiene dimer and styrene under the operating conditions prescribed in this test method. 5.2 Recorder--A 0 to l-mV, 0 to 5-mV, or 0 to lO-mV recorder with a full-scale response time of 2 s or less, and with sufficient sensitivity to meet the requirements of 5. I. 5.3 Column--Any column may be used that is capable of resolving the butadiene dimer and styrene as discrete peaks, quantitatively proportional to concentration and within an elapsed time sufficiently short to be practical. (See Note 1.) 5.4 Liquid Sampling Valve--Any liquid sampling valve may be used that will permit the reproducible introduction of the butadiene concentrate as a liquid under its vapor pressure or higher and in a quantity sufficient to meet the sensitivity and resolution requirements in 5.1 and 5.3, respectively. 5 6. Reagents and Materials 6.1 4- Vinylcyclohexene.1 and Styrene, for calibration, purity of not less than 99 %. 6.2 Carrier Gas--Helium or hydrogen for use on thermal conductivity detector units; or nitrogen, helium, or argon for use on ionization detector units.

3. Summary of Test Method 3.1 The sample is introduced into a gas-liquid partition column. The components of interest are separated as they are transported through the column by a carrier gas, and their presence in the effluent is detected and recorded as a chromatogram. Packed columns are used, and either thermal conductivity or ionization detectors are permissible. The quantity of the components of interest present in the sample is determined from the chromatogram by comparing their peak areas or heights with those obtained from a synthetic sample.

NOTE 1: Warning----Compressed gas. H a z a r d o u s pressure. NOTE 2: W a r n l n g - - H y d r n g e n gas is flammable. Hazardous pressure.

6.3 Liquid Phase, for column. NOTE 3 - - T h e following materials have been used successfully as liquid phases: Carbowax 400, 1500, i 540

4. Significance and Use 4.1 Butadiene dimer and styrene may be present as impurities in commercial butadiene. This test method is

General Electric SE-30 siliconegum rubber Polyethyleneglycol6000 Barecowax 1035 Dow Coming silicone oil Carbowax 20M + Dow Coming Hi Vae.

This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.0D on Hydrocarbons for Chemical and Special Uses. Current edition approved Feb. 15, 1993. Published May 1993. Originally published as D 2426 - 65 T. Last previous edition D 2426 - 86. 2 Annual Book of ASTM Standards, Vol 05.01. Annual Book of ASTM Standards, Vol 05.05. Annual Book of ASTM Standards, Vol 14.01.

6.4 Solid Support, for use in packed column, usually crushed fire brick or diatomaceous earth. Sieve size will depend on the diameter of the column used and support s Suitable valves are commercially available.

352

~[~) D 2426 loading and should be such as to give optimum resolution and analysis time.

Area methods found to be acceptable include planimetering, integration, and triangulation (multiplying the peak height by the width at the half-height). In peak area or height methods care must be taken so that chromatograph operating parameters such as column temperature and carrier gas flow rate are kept at the same conditions on botli the synthetic standard and the sample. Calculate the percentage by weight of each component as follows: Concentration, weight% = (A,/Ao) x S x (Go/Gs) (1) where: As = peak area or height of component in the sample, Ao = peak area or height of component in the synthetic

7. Preparation of Apparatus 7.1 Column PreparationmAny satisfactory method, used in the practice of the art, that will produce a column meeting the requirements of 5.3. See Appendix X2 of Method D 1945, also see 6.1 of Test Method D 2593. 7.2 Chromatograph--Put in service in accordance with the manufacturer's instructions. The injector temperature shall be no greater than 5°C above the column oven temperature. The column oven temperature shall not exceed 185"C. See Table 1 for typical operating conditions. 7.3 Synthetic Blends--Prepare a synthetic mixture from 99 tool % minimum pure 4-vinylcyclohexene-I and styrene in a suitable matrix in approximately the same concentration expected in the sample. The matrix may be any one of the normal paraffin hydrocarbons from butane to heptane, inclusive. In preparing the blend, weigh each compound added with sufficient precision to result in a mixture accurate to 5 % relative or 0.02 % absolute, whichever is greater. Transfer the blend to a container of the type to be used for the sample and pressure with a suitable gas.

blend, S = weight % of component in the synthetic blend, Gs = relativedensity 60/60 of the sample, and Go = relativedensity 60/60 of the synthetic blend. NOTE 5 - - T h e specific gravity of the sample may be determined in

accordance with Test Method D 1657 and the specificgravity of the syntheticmay be assumedto be equal to the gravityof solvent used to prepare the blend. A list of such gravities is found in STP 109 A, Physical Constants of Hydrocarbons.Ca to C~o.6 10. Precision and Bias I0.1 The precision of this test method as determined by statistical examination ofinterlaboratory results is as follows: 10.1.I Repeatability--The difference between successive test results, obtained by the same operator with the same apparatus under constant operating conditions on identical test material would, in the long run, and in the normal and correct operation of the test method, exceed the following values only in one case in twenty:

8. Procedure 8.1 Using the liquid sampling valve, inject into the column the desired volume of synthetic blend and record the peaks at a sensitivity setting that allows the maximum peak height. Pressure the sample cylinder with a suitable gas to a pressure sufficient to ensure no flashing in the line to the sampling valve or in the valve itself. Using the same sample size and instrument conditions, inject the sample into the column and record the peaks. (See Table 1 for typical operating conditions.)

Repeatability 0.005 0.044

10.1.2 Reproducibility--The difference between two single and independent results obtained by different operators working in different laboratories on identical test material would, in the long run, and in the normal and correct operation of the test method, exceed the following values only in one case in twenty:

NOTe 4: Warning--Butadienegas is flammableunder pressure. 9. Calculation 9.1 Peak MeasurementmMeasure the peak area or height of each component of interest in both the synthetic blend and the sample. Measurement may be accomplished by any method that meets the precision requirements of Section 10. TABLE 1

Concentration 0.15 1.49

Dimer, wt % Styrene, wt %

6 Available as a separate publication from ASTM.

Columns and Conditions Used Successfully ~ a +xDow 20M Coming HI Vac

Polyethylene C~ycol-6000

Barecowax 1035

iC,oatecr)

3.1 6.4 100-128 0.75 each Silica

3.7 4.8 155 30 Chromosorb P

8.1 6.4 140 20 Chr(:xnoso~ P

30050

50-80

eo

i5

~

171

o0

HFI 0.07 integrator

HFI 1.54 triangulation

T.C. 1.03 triangulation

T.C. 8.69 peak height

T.C. 3.0 planimeter

DOW Silicone 200

Carbowax 1500

Carbowax 1540

Colurnn length, m Column diameter, mm ~ n temperature, °C liquid phase, wt '~ Support material

1.5 3.2 85 10 C,hromosorb P

4.6 4.8 110 15 TFEfluorocarbon

3.7 6.4 100 16 Chromosorb P

Mesh Carder flow, mL/min Detector Sarnpla size, pL Peek measurement

80-100 19 HFP 0.77 triangulation

eo T.C. a 20 triangulation

Silicone SE-80 15.2 0.5 75

lOO-12o

A HFI ,,, hydrogen flame ionization. B T.C. ,, thermal conductivity.

353

~1~ D 2426 Concentration Dimer,wt % Styrene,wt M

0.15

1.49

Reproducibility 0.018 0.051

method for measuring Dimer and Styrene, bias has not been determined.

10.2 Bias-.~ince there is no accepted reference material suitable for determining the bias for the procedure in this test

11. Keywords 11.1 butadiene concentrate; butadiene dimmer; gas chromatography; Styrene

The ~ Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned In this standard. Users of this standard are expresaly edvlaed that dstermlnstlon of the validity of any such pstant r~hts, and the risk of Infr~ngemontof ~ riglea, are entirety thor own respon~bitity. stondud Is subject to revlalon at any time by the responsible t ~ h n l ~ l ~mmittee and must be reviewed every five years and if not revlud, either r e w ~ or withdrawn. Your ~ e n a n ~ are Invited alther for revlalon of this standerd or for additionalstandards and ehould be eddreesed to ASTM Headquarters. Your ¢~=rnmantRwill receive careful consldenltion st • meeting of the responsible technical oornmibee, which you may attend. If you feel that your commer~s have not received • fair hearing you ahould make your view• known to the ASTM Committee on Standards, 1916 Race St., Ph//edalph/a, PA 10103.

354

Designation: D 2500 - 91

®

An Amerk:an National Standard Bfltlsh Standard 4458

Designation: 219/82

Standard Test Method for Cloud Point of P e t r o l e u m Products I This standard is issued under the fixed designation D 2500; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (0 indicates an editorial change since the last revision or rcapproval.

This test method was adopted as an ASTM-IP Standard. This standard has been approvedfor use by agencies of the Department of Defense. Consult the DoD Index of Specifications and Standards for the specific year of issue which has been adopted by the Department of Defense.

1. Scope 1.1 This test method covers only petroleum products which are transparent in layers 40 mm in thickness, and with a cloud point below 49°C.

U

~.-~

1.2 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicabtTity of regulatory limitations prior to use. For specific

E M

m

L

~

-!7

hazard statements see Notes 2, 3, 4, and 5.

2. Referenced Documents

lmT4qt

2.1 A S T M Standard: E 1 Specification for ASTM Thermometers 2 2.2 IP Standard: Specifications for IP Standard Thermometers 3

m mklN

[] [ ]

m

3. Terminology 3.1 Description of Term Specific to This Standard: 3.1.1 cloud pointmthe temperature at which a cloud of wax crystals first appears in a liquid when it is cooled under conditions prescribed in this test method.

iiMn M anfalm* It mllmstlm

FIG. 1 Apparatus for Cloud Point Test

4. Summary of Test Method 4. I The sample is cooled at a specified rate and examined periodically. The temperature at which a cloud is first observed at the bottom of the test jar is recorded as the cloud point.

inside diameter of the jar may range from 30 to 32.4 mm within the constraint that the wall thickness be no greater than 1.6 ram. The jar should be marked with a line to indicate sample height 54 + 3 mm above the inside bottom. 6.2 Thermometers, having ranges shown below and conforming to the requirements as prescribed in Specifications E I or Specifications for IP Standard Thermometers.

5. Significance and Use 5.1 The cloud point of a petroleum product is an index of the lowest temperature of its utility for certain applications.

6. Apparatus (See Fig. 1) 6.1 Test Jar, clear, cylindrical glass, fiat bottom, 33.2 to

Thermometer

Temperature Range

34.8-mm outside diameter and 115 and 125-mm height. The

High cloud and pour Low cloud and pour

This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direft responsibility of Subcommittee D02.07 on Flow Properties. Current edition approved Oct. 15, 1991. Published December 1991. Originally published as D 2500 - 66. Last previous edition D 2500 - 88. 2 Annual Book of ASTM Standards, Vol 14.01. 3 Available from 61 New C4wendish St., London, England WIM BAR.

6.3 Cork, to fit the test jar, bored centrally for the test thermometer. 6.4 Jacket, metal or glass, watertight, cylindrical, flat bottom, about 115 mm in depth, with an inside diameter of 44.2 to 45.8 mm. It must be supported free of excessive vibration and firmly in a vertical position in the cooling bath 355

-38 to +50"C -80 to +20"C

Thermometer Number ASTM IP 5C 6C

IC 2C

~

D 2500 -36*C. Adjust the position of the cork and the thermometer so that the cork fits tightly, the thermometer and the jar are coaxial, and the thermometer bulb is resting on the bottom of the jar. NOTE 6--Liquid column separation of thermometers occasionally occurs and may escape detection. Thermometers should be checked immediately prior to the test and used only if their ice points are 0 + I'C, when the thermometer is immersed to the immersion line in an ice bath, and when the emergent column temperature does not differ significantly from 21"C. Alternatively, immerse the thermometer to a reading and correct for the resultant cooler stem temperature.

of 6.7 so that not more than 25 m m projects out of the cooling medium. 6.5 Disk, cork or felt, 6 mm thick to fit loosely inside the jacket. 6.6 Gasket, ring form, about 5 mm in thickness, to fit snugly around the outside of the test jar and loosely inside the jacket. The gasket may be made of rubber, leather, or other material which is elastic enough to cling to the test jar and hard enough to hold its shape. Its purpose is to prevent the test jar from touching the jacket. 6.7 Bath or baths, maintained at prescribed temperatures with a firm support to hold the jacket vertical. The required bath temperatures may be maintained by refrigeration if available, otherwise by suitable freezing mixtures. NOTE I--The mixtures commonly used for temperatures down to those shown are as follows: ice and water 10°C Crushed ice and sodium chloride crystals Crushed ice and calcium chloride crystals Acetone, methyl or ethyl alcohol, or petroleum naphtha chilled in a covered metal beaker with an ice-salt mixture to - 12"C, then with enough solid carbon dioxide to five the desired temperature

8.4 See that the disk, gasket, and the inside of the jacket are clean and dry. Place the disk in the bottom of the jacket. The disk and jacket shall have been placed in the coofing medium a minimum of 10 min before the test jar is inserted. The use of a jacket cover while the empty jacket is cooling is permitted. Place the gasket around the test jar, 25 m m from the bottom. Insert the test jar in the jacket. Never place a jar directly into the cooling medium.

-12"(:: -26"C -57"C

NOTE 7--Failure to keep the disk, gasket and the inside ofthe jacket clean and dry may lead to frost formation which may cause erroneous results.

7. Reagents and Materials

7.1 Acetone--Technical grade acetone is suitable for the cooling bath, provided it does not leave a residue on drying. NOTE 2: Warning--Extremely flammable. 7.2 Calcium ChloridemCommercial or technical grade calcium chloride is suitable. 7.3 Carbon Dioxide (Solid) or Dry IcemA commercial grade of dry ice is suitable for use in the cooling bath. 7.4 Ethanol or Ethyl Alcohol--A commercial or technical grade of dry ethanol is suitable for the cooling bath. NOTE 3: Warning--Flammable. Denatured, cannot be made nontoxic. 7.5 Methanol or Methyl Alcohol--A commercial or technical grade of dry methanol is suitable for the cooling bath. NoTE 4: Warning--Flammable. Vapor harmful. 7.6 Petroleum Naphtha--A commercial or technical grade of petroleum naphtha is suitable for the cooling bath. NOTE 5: Warning--Combustible. Vapor harmful. 7.7 grade 7.8 dium

Sodium Chloride Crystals--Commercial or technical sodium chloride is suitable. Sodium Sulfate--A reagent grade of anhydrous sosulfate should be used when required (see Note 7).

8. Procedure 8.1 Bring the oil to be tested to a temperature at least 14°C above the approximate cloud point. Remove any moisture present by a method such as filtration through dry lintless filter paper until the oil is perfectly clear, but make such filtration at a temperature of at least 140C above the approximate cloud point. 8.2 Pour the clear oil into the test jar to the level mark. 8.3 Close the test jar tightly by the cork carrying the test thermometer. Use the High Cloud and Pour Thermometer if the expected cloud point is above -36*C and the Low Cloud and Pour Thermometer if the expected cloud point is below

8.5 Maintain the temperature of the cooling bath at - l to +2°C. 8.6 At each test thermometer reading that is a multiple of I°C, remove the test jar from the jacket quickly but without disturbing the oil, inspect for cloud, and replace in the jacket. This complete operation shall require not more than 3 s. If the oil does not show a cloud when it has been cooled to 10°C, transfer the test jar to a jacket in a second bath maintained at a temperature o f - 18 to -15°C (see Table 1). Do not transfer the jacket. If the oil does not show a cloud when it has been cooled to -7°C, transfer the test jar to a jacket in a third bath maintained at a temperature o f - 3 5 to -32"C. For the determination of very low cloud points additional baths are required, each bath to be maintained at 17"C below the temperature of the preceding bath (see Table I). In each case transfer the jar to the next bath when the temperature of the oil comes to 28°C above the low end of the temperature setting of the temperature of the next bath (see Table I). 8.7 Report the cloud point, to the nearest I'C, at which any cloud is observed at the bottom of the test jar, which is confirmed by continued cooling. NOTE 8--A wax cloud or haze is always noted first at the bottom of the test jar where the temperature is lowest. A slight haze throughout the entire sample, which slowlybecomes more apparent as the temperature is lowered, is usually due to traces of water in the oil. Generally this water haze will not interfere with the determination of the wax cloud point. In most cases of interference, t'fltration through dry lintless filter papers such as described in 8. I is sufficient. In the case of diesel fuels, however,if the haze is very dense, a fresh portion of the sample should be dried by shaking 100 mL with 5 g of TABLE 1

Bath 1 2 3 4 5

356

Bath and Sample Temperature Ranges

Bath Temperature Setting, °C -1 to2 -18 to -15 -35 to -32 -52 to -49 -69 to -66

Sample Temperature Range, °C Start to 10 10 to - 7 - 7 to -24 -24 tO -41 -41 to -58

q~) D 2500 suits, obtained by the same operator with the same apparatus under constant operating conditions on identical test matedal, would in the long run, in the normal and correct operation of this test method exceed 2"C for distillate oils and 6"C for other oils only in one case in twenty. 10.3 Reproducibility--The difference between two single and independent results obtained by different operators working in different laboratories on identical test material, would in the long run, in the normal and correct operation of this test method, exceed 4"C for distillate oils and 6"C for other oils only in one case in twenty. 10.4 Bias--The procedure in this test method has no bias, because the value of cloud point can be defined only in terms of a test method.

anhydrous sodium sulfate for at least 5 min and then filtering through dry lintless filter paper. Given sufficient contact time, this procedure will remove or sufficiently reduce the water haze so that the wax cloud can be readily discerned. Drying and filtering should be done always at a temperature at least 14"C above the approximate cloud point but otherwise not in excess of

49"C.

9. Report 9.1 Report the temperature recorded in 8.7 as the Cloud Point, Test Method D 2500. 10. Precision and Bias 10.1 The precision of this test method as determined by statistical examination of interlaboratory results is as follows: 10.2 Repeatability--The difference between two test re-

11. Keywords 11.1 cloud point; petroleum products; wax crystals

The American Society for Testing and Materials takes no position respecting the vahdlty of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the vahdlty of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is sublect to rewslon at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reapproved or withdrawn Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend If you feel that your comments have not received a fair hearing you should make your wews known to the ASTM Committee on Standards, 100 Bart" Harbor Drive, West Conshohocken, PA 19428.

357

(~l~ Designation: D 2501 - 91 Standard Test Method for Calculation of Viscosity-Gravity Constant (VGC) of Petroleum Oils 1 This standard is issued under the fixed designation D 2501; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (~) indicates an editorial change since the last revision or reapproval.

3. Summary of Test Method 3.1 The kinematic viscosity at 40"C (104*F) and the density at 15"C of the oil are determined. If the oil is extremely viscous, or if it is otherwise inconvenient to determine the viscosity at 40"C, the kinematic viscosity at 100*C (212"F) can be used. The viscosity-gravity constant is calculated from the measured physical properties using the appropriate equation.

1. Scope 1.1 This test method covers the calculation of the viscosity-gravity constant (VGC) of petroleum oils2 having viscosities in excess of 4 cSt. = 4 x 10 - 6 m-2/s at 40"C (104°F). 1.2 Annex A 1 describes a method for calculating the VGC from Saybolt (SUS) viscosity and relative density. 1.3 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 1.4 The values stated in either acceptable SI units or in other units shall be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system must be used independently of the other, without combining values in any way.

4. Significance and Use 4.1 The viscosity-gravity constant (VGC) is a useful function for the approximate characterization of the viscous fractions of petroleum. 2 It is relatively insensitive to molecular weight and is related to a fluids composition as expressed in terms of certain structural elements. Values of VGC near 0.800 indicate samples of paraftinic character, while values close to 1.00 indicate a preponderance of aromatic structures. Like other indicators of hydrocarbon composition, the VGC should not be indiscriminately applied to residual oils, asphaltic materials, or samples containing appreciable quantities of nonhydrocarbons.

2. Referenced Documents 2.1 A S T M Standards: D 287 Test Method for API Gravity of Crude Petroleum and Petroleum Products (Hydrometer Method) 3 D445 Test Method for Kinematic Viscosity of Transparent and Opaque Liquids (and the Calculation of Dynamic Viscosity)3 D 1298 Test Method for Density, Relative Density (Specific Gravity), or API Gravitt of Crude Petroleum and Liquid Petroleum Products by Hydrometer Method 3 D2140 Test Method for Carbon-Type Composition of Insulating Oils of Petroleum Origin 4 D 4052 Test Method for Density and Relative Density of Liquids by Digital Density M e t e : 2.2 Other Document: ASTM-IP Petroleum Measurement Tables 6

5. Measurement of Physical Properties 5.1 Preferably, determine the kinematic viscosity at 400C as described in Test Method D 445. However, if the sample is extremely viscous or if it is otherwise inconvenient to measure the viscosity at 40oc, the viscosity at 100oc may be determined. 5.2 Determine the density at 15oc in accordance with Test Method D 1298 or Test Method D 4052. Equivalent results can be obtained by determining API Gravity at 60*F (15.560C) in accordance with Test Method D287, and converting the result to density at 15oc by means of Table 3 of the Petroleum Measurement Tables (American Edition). 6 NOTE l - - l f it is necessary to convert a result obtained using the digital density meter to a density at another temperature, the Petroleum Measurement Tables can be used only if the glass expansion factor has been excluded.

This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D 02.04 on Hydrocarbon Analysis. Current edition approved Oct. 15, 1991. Published December 1991. Originally published as D 2501 - 66. Last previous edition D 2501 - 87. 2 Coats, H. B., and Hill, J. B., Industrial and Engineering Chemtstry, Vol 20, 1928, p. 641. 3 Annual Book oJ ASTM Standards, Vol 05.01. 4 Annual Book of ASTM Standards, Vol 10.03. ~ Annual Book of ASTM Standards, Vol 05.03. ~' Published jointly by, and available from the American Society of Testing and Materials, 1916 Race St., Philadelphia, PA 19103, and the Institute of Petroleum, 61 New Cavendish St., London WIM 8AP, Compamon volumes--the British Edition and the Metric Edition--are also available. These tables supersede all other similar tables previously published by either of these societies and the National Bureau of Standards Circular C-410 and the supplement to Circular C-410.

6. Calculation of Viscosity-Gravity Constant 6.1 From Kinematic Viscosity at 40°C and Density at 15°C--Use the following equation to calculate the VGC from the measured properties: VGC =

G - 0.0664 - 0.1154 Log(V- 5.5) 0.94 - 0.109 Log(V- 5.5)

where: G = density at 150C, g/mL, and V = kinematic viscosity at 400C, eSt.

358

(1)

~

D 2501

6.2 From Kinematic Viscosity at IO0*C and Density at 15*C--Use the following equation to calculate the VGC: VGC

=

G - 0.108 - 0.t255 Log(V' - 0.8) 0.90 - 0.097 L o g ( V '

-

where: r r = precision of the VGC, rcs = precision of the gravity from D 287, rv = precision of the viscosity from D 445, V = measured viscosity, and Y = VGC. 8.2.2 For viscosity measured at 100*C,

(2)

0.8)

where: G = density at 15"C, g/mL, and V' = kinematic viscosity at 100*C, cSt.

1

r~,-- 0.90 - 0.097 logjo ( V - 0.8)

7. Report

7.1 Report the calculated VGC to the nearest .002 unit. 7.2 If the viscosity at 100*C was used for the calculation, state this in the report.

•

8.1 The calculation of viscosity-gravity constant from kinematic viscosity at 40°C and density at 150C is exact. Precision limits are not assigned to this calculation. 8.2 The precision of the calculated VGC is dependent only on the precision of the original determinations of viscosity and density• Those precision statements are found in their respective test methods. The precision can be calculated as follows: 8.2.1 For viscosity measured at 40"C, 1

•

" r~7 0.00177(Y- 1.294)2 r°- + ( V - 0.8)2

8.3 The VGC calculated from the viscosity at 100*C can differ slightly from that calculated from the viscosity at 40"C. A statistical evaluation of VGC data derived from equivalent viscosities at both 100*F and 210*F suggests that in the range from about 0.80 to 0.95 VGC, the expected average difference will be approximately 0.003 units. Whenever possible, it is preferable to determine the VGC using Eq 1. 8.4 Bias--The procedure in Test Method D 2501 for calculation of viscosity-gravity constant has no bias because the value of viscosity-gravity constant can be defined only in terms of a test method. 8.5 The term viscosity-gravity constant is also used in Test Method D 2140, for determining carbon-type composition of insulating oils of petroleum origin. The equations used are different from those in this test method; the bias between the two test methods is unknown.

8. Precision and Bias

rr = 0.94 - 0.109 loglo ( V - 5.5)

(4)

(3) ,0.00224 ( Y - 1.059)2 ( V - 5.5)2

r(i 2 dr. r l , .

9. Keywords 9.1 aromatic; density; kinematic viscosity; paraffinic

ANNEX (Mandatory Information)

AI. CALCULATION OF VISCOSITY-GRAVITY CONSTANT FROM SAYBOLT VISCOSITY AND RELATIVE DENSITY (SPECIFIC GRAVITY) A I. 1 The calculation of viscosity-gravity constant (VGC) can also be calculated from viscosity in units of Saybolt seconds universal (SUS) and relative density (specific gravity). AI.2 From Saybolt Viscosity at IO0*F and Relative Density (Specific Gravity) 60~60*F--Use the following equation to calculate the VGC from the measured properties:

VGC =

10G - 1.0752 log ( V - 38) 10 - log ( V - 38)

sity (Specific Gravity) 60/60*F--Use the following equation to calculate the VGC: VGC=

G - 0.12441og(V~ - 31) -0.0839 0.9255 - 0.0979 log(V1 - 31)

(All)

where: G = relative density (specific gravity) at 60/60"F, and V, = Saybolt Universal viscosity at 210*F. A I.4 The viscosity-gravity constant calculated from the Saybolt viscosity at 210*F can differ slightly from that calculated from the 100*F viscosity• A statistical evaluation of VGC data derived from both the 100*F and 210*F viscosities suggests that in the range from about 0.80 to 0.5 VGC, the expected average difference will be approximately 0.003 units. Whenever possible, it is preferable to determine the VGC using Eq A 1.1.

(AI.1)

where: G = relative density (specific gravity) at 60/60"F, and V = Saybolt Universal viscosity at 100*F. A1.3 From Saybolt Viscosity at 210"F and Relative Den-

359

fl~ D 2501 The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103.

360

(I~T~ Designation: D 2502 - 92

An Arnerican National Standard

Standard Test Method for Estimation of Molecular Weight (Relative Molecular Mass) of Petroleum Oils From Viscosity Measurements 1 This standard is issued under the fixed designation D 2502; the number immediatel~ lbllo~ing the designation indicates the year of original adoption or, in the ease of revision, the year of last revision. A number in parcnthe~s indicates the year of last reapproval. A superscript epsilon (E) indicates an editorial change since the last revision or reapproval.

1. Scope 1.1 This test method covers the estimation of the mean molecular weight (relative molecular mass) of petroleum oils from kinematic viscosity measurements at 100 and 210*F (37.78 and 98.89"C). 2 It is applicable to samples with molecular weights in the range from 250 to 700 and is intended for use with average petroleum fractions. It should not be applied indiscriminately to oils that represent extremes of composition or possess an exceptionally narrow molecular weight (relative molecular mass) range. 1.2 Values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are provided for information purposes only. 1.3 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate sa~,ty and health practices and determine the applicability of regulatory limitations prior to use.

4.2 Molecular weight (relative molecular mass) is a fundamental physical constant that can be used in conjunction with other physical properties to characterize hydrocarbon mixtures. 5. Procedure 5.1 Determine the kinematic viscosity of the oil at 100 and 210*F (37.78 and 98.89"C) as described in Test Method D 445. 5.2 Look in Table 1 for 100*F (37.78"C) viscosity and read the value of H that corresponds to the measured viscosity. Linear interpolation between adjacent columns may be required. 5.3 Read the viscosity - molecular weight chart for H and 210*F (98.89"C) viscosity. A simplified version of this chart is shown in Fig. 1 for illustration purposes only (Note). Interpolate where necessary between adjacent lines of 210*F viscosity. After locating the point corresponding to the value of H (ordinate) and the 210*F viscosity (superimposed lines), read the molecular weight along the abscissa. Example: Measured viscosity, cSt: 100*F (37.78"C) = 179 210*F (98.89"C) = 9.72 Look in Table 1 for 179 and read the corresponding value H = 461. Using H = 461 and 210*F viscosity = 9.72 in conjunction with chart gives molecular weight (relative molecular mass) = 360 (see Fig. 1).

2. Referenced Documents

2.1 ASTM Standard: D445 Test Method for Kinematic Viscosity of Transparent and Opaque Liquids (and the Calculation of Dynamic Viscosity)3 2.2 Adjunct: Molecular Weight of Petroleum Oils from Viscosity Measurements (D 2502) 4 3. Summary of Test Method 3.1 The kinematic viscosity of the oil is determined at 100 and 21O°F (37.78 and 98.89°C). A function " H " of the 100°F viscosity is established by reference to a tabulation of H function versus 100*F viscosity. The H value and the 210*F viscosity are then used to estimate the molecular weight from a correlation chart.

NOTE I--A 22 by 28-in. (559 by 711-mm) chart available as an adjunct to this test method was used in cooperative testing of the method. If other charts are used, the precision statements given in the Precision Section will not apply. 5.4 Report the molecular weight to the nearest whole number.

4. Significance and Use 4.1 This test method provides a means of calculating the mean molecular weight (relative molecular mass) of petroleum oils from another physical measurement.

6. Precision and Bias 6.1 The precision of this test method as obtained by statistical examination of interlaboratory test results is as follows: 6.1.1 Repeatability--The difference between successive test results obtained by the same operator with the same apparatus under constant operating conditions on identical test material, would in the long run, in the normal and correct operation of the test method, exceed the value 3 g/tool only in one case in twenty. 6.1.2 Reproducibility--The difference between two single and independent results, obtained by different operators,

This test method is under the jurisdiction of ASTM Committee !)-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee 1:)02.04 on Hydrocarbon Analysis. Current edition approved Aug. 15, 1992. Published October 1992. Originally published as D 2502 - 66 T. Last previous edition D 2502 - 82. 2 Hirschler, A. E., Journal of the lnstitnte of Petroleum, JIPEA, Vol 32, 1946, p. 133. 3 Annual B¢u~ko[ASTM Standards, Vol 05.01. 4 Available from ASTM Headquarters. Order PCN 12-425020-00.

361

(~ D 2502 accordance with RR:D02-1007, "Manual on Determining Precision Data for ASTM Methods on Petroleum Products and Lubricants. ''5

working in different laboratories on identical test material, would in the long run, in the normal and correct operation of the test method, exceed the value 25 g/mol only in one case in twenty. 6.2 BiasmSince there is no accepted reference material suitable for determining bias for this test method, no statement of bias can be made. 6.3 The precision for this test method was not obtained in

7.

Keywords 7.1 kinematic viscosity; molecular weight; petroleum oils; relative molecular mass 5 ,Immal Book oI'..ISTM Standards, Vol 05.03.

TABLE 1

Tabulation of H Function

Kinematic Viscosity, cSt, at 100*F (37.780C)

H 0

0.2

0.4

0.6

0,8

2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39

-178 -67 -1 44 79 106 128 147 163 178 190 201 211 221 229 237 244 251 257 263 269 274 279 283 288 292 296 300 304 307 310 314 317 320 323 326 328 331

-151 -52 9 52 85 111 132 151 166 180 192 203 213 222 231 238 245 252 258 264 270 275 280 284 289 293 297 301 304 308 311 314 317 320 323 326 329 332

-126 -38 19 59 90 116 136 154 169 183 195 206 215 224 232 240 247 253 259 265 271 276 281 285 289 294 298 301 305 308 312 315 318 321 324 327 329 332

-104 -25 28 66 96 120 140 157 172 185 197 208 217 226 234 241 248 255 261 266 272 277 281 286 290 294 298 302 306 309 312 316 319 322 325 327 330 333

-85 -13 36 73 101 124 144 160 175 188 199 210 219 227 235 243 249 256 262 267 273 278 282 287 291 295 298 303 306 310 313 316 319 322 325 328 331 333

H

40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190

0

1

2

3

4

5

6

7

8

9

334 355 372 386 398 408 416 424 431 437 443 448 453 457 461 465

336 357 374 387 399 409 417 425 432 438 443 449 453 458 462 466

339 359 375 388 400 410 418 425 432 438 444 449 454 458 462 466

341 361 377 390 401 410 419 426 433 439 444 450 454 459 463 466

343 363 378 391 402 411 420 427 433 439 445 450 455 459 463 467

345 364 380 392 403 412 420 428 434 440 446 450 455 460 463 467

347 366 381 393 404 413 421 428 435 441 446 451 456 460 464 468

349 368 382 394 405 414 422 429 435 441 447 451 456 460 464 468

352 369 384 395 406 415 423 430 436 442 447 452 456 461 465 468

354 371 385 397 407 415 423 430 437 442 448 452 457 461 465 469

362

~') D 2502 TABLE 1

Continued

Kinematic Viscosity, cSt at 100°F (37.78°C)

0

10

20

30

40

50

60

70

80

90

200 300 400 500 600 700 800 900

469 497 515 529 540 549 557 563

473 499 517 530 541 550 557 564

476 501 518 531 542 551 558 565

479 503 520 533 543 551 559 565

482 505 521 534 544 552 559 566

485 507 523 535 545 553 560 566

487 509 524 536 546 554 561 567

490 511 525 537 547 554 562 567

492 512 527 538 547 555 562 568

495 514 528 539 548 556 663 569

0

100

200

300

400

500

600

700

800

900

569 605 625 638 648 656 663 668 673

574 608 626 639 649 657 664 669 674

578 610 628 640 650 658 664 670 674

583 612 629 641 651 658 665 670 675

587 614 631 642 652 659 665 671 675

591 616 632 643 652 660 666 671 676

594 618 633 644 653 660 666 671 676

597 620 634 645 654 661 667 672 677

600 621 636 646 655 662 667 672 677

603 623 637 647 656 662 668 673 677

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

678 705 720 731 739 745 750 755 759 762

681 707 722 732 739 746 751 755 759 762

684 709 723 732 740 746 751 756 759 763

688 711 724 733 741 747 752 756 760 763

691 712 725 734 74t 747 752 756 760 763

694 714 726 735 742 748 753 757 760 764

696 715 727 736 743 748 753 757 761 764

699 717 728 736 743 749 753 758 761 764

701 718 729 737 744 749 754 758 761 764

703 719 730 738 744 750 754 758 762 765

1 2 3 4 5 6 7 8 9

000 000 000 000 000 000 000 000 000

10 000 20 000 30 000 40 000 50 000 60 000 70 000 80 000 90 000 100 000

H

300 . , ~

400

500

600

RELATIVEMOLECULARMASS FIG. 1

Viscosity-Molecular Weight Chart

363

700

~t~) D 2502 The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reepproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at s meeting of the responsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103.

364

q~T~

Designation: D 2 5 0 3 - 92

An Amencan National Standard

Standard Test Method for Relative Molecular Mass (Molecular Weight) of Hydrocarbons by Thermoelectric Measurement of Vapor Pressure This standard is issued under the fixed designation D 2503; the number immediately following the designation indicates the year of original adoption or, in the ease of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (0 indicates an editorial change since the last revision or reapproval.

This Wst method has been approvedfor use by agencies of the Department oJ'De./ense. Consult the DoD huh,x ol Spec~ficatums and Standards for the specific year of issue which has been adopted by the Department of DeJense.

4. Apparatus 4. l Vapor Pressure Osmometer, with operating diagram. 2

1. Scope 1.1 This test method covers the determination of the average relative molecular mass (molecular weight) of hydrocarbon oils. It can be applied to petroleum fractions with molecular weights (relative molecular mass) up to 3000; however, the precision of the method has not been established above 800 molecular weight (relative molecular mass). The method should not be applied to oils having initial boiling points lower than 220"C. 1.2 Values stated in SI units are to be regarded as the standard. The values given in parentheses are provided for information purposes only. 1.3 This standard does not purport to address all of the

5. Reagents and Materials 5.1 Purity of Reagents--Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, where such specifications are available) Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination. 5.2 Solvents--Solvents that do not react with the sample must be used. Since many organic materials exhibit a tendency to associate or dissociate in solution, it is desirable to use polar solvents for polar samples and nonpolar solvents for nonpolar samples. The solvents listed have been found suitable for hydrocarbons and petroleum fractions. 5.2.1 Benzene

safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements, 5.2.1, 5.2.3, and 5.2.3.

2. Summary of Test Method 2.1 A weighed portion of the sample is dissolved in a known quantity of appropriate solvent. A drop of this solution and a drop of solvent are suspended, side by side, on separate thermistors in a closed chamber saturated with solvent vapor. Since the vapor pressure of the solution is lower than that of the solvent, solvent condenses on the sample drop and causes a temperature difference between the two drops. The resultant change in temperature is measured and used to determine the relative molecular mass (molecular weight) of the sample by reference to a previously prepared calibration curve.

NOTE l: Warning--Poison. Carcinogen. Harmful if swallowed. Extremely flammable.Vapors may cause flash fire. Vapor harmful, may be absorbed through skin. 5.2.2 Chloroform NOTE 2: Warning--May be fatal if swallowed. Harmful if inhaled. May produce toxic vapors if burned. 5.2.3 l,l,l- Trichloroethane NOTE 3: WarningIHarmful if inhaled. High concentrations may cause unconsciousnessor death. Contact may cause skin irritation and dermatitis. NOTE 4IThe precision data given in 10.1 and 10.2 will apply only when benzene is used as the solvent. There is also some evidence that determinations on the same oil sample carried out in different solvents will produce results that differ somewhat in absolute magnitude of apparent molecularweight (relative molecular mass).

3. Significance and Use 3.1 Relative molecular mass (molecular weight) is a fundamental physical constant that can be used in conjunction with other physical properties to characterize pure hydrocarbons and their mixtures. 3.2 A knowledge of the relative molecular mass (molecular weight ) is required for the application of a number of correlative methods that are useful in determining the gross composition of the heavier fractions of petroleum.

5.3 Reference Standards--A calibration curve must be constructed for each new lot of solvent using a pure compound whose relative molecular mass (molecular weight) is 2 A vapor pressure osmomcter is available from H. Knauer and Co., Berlin, West Germany. The manufacture ofthe Mechrolab instrument previously referred to in this footnote has been discontinued. I Iowcver, .,,onle models zn:ly I'u.,;.Ivall-'d~l¢ from stocks on hand at laboratory supply houses, or as used equipment from laboratory instrument exchanges. 3 "Reagent Chemicals, American Chemical Society Specifications," Am. Chemical Soc., Washington, IX:. For suggestions on the testing of reagents not listed by the American Chemical Society, see "Analar Standards for Laboratory U.K. Chemicals," BDH Ltd., Poole, Dorset, and the "United States Pharmacopeia."

J This test method is under the jurisdiction of ASTM Committee 1:)-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.04 on Hydrocarbon Analysis. Current edition approved Aug. 15, 1992. Published October 1992. Originally published as D 2503 - 66T. Last previous edition D 2503 - 82 (1987)~t.

365

~) D 2503 TABLE 1 Precision Data (Benzene Solvent)

accurately known. Compounds that have been used successfully include benzil (210.2), n-octadecane (254.5), and squalane (422.8). 6. Sampling 6.1 The sample must be completely soluble in the selected solvent at concentrations of at least 0.10 M, and it must not have an appreciable vapor pressure at the test temperature. 7. Preparation and Calibration of Apparatus 7.1 Prepare standard 0.01, 0.02, 0.04, 0.06, 0.08, and 0.1 M solutions of the calibrating compound in the solvent selected. 7.2 Remove the upper sample chamber assembly. Rinse the solvent cap with the solvent to be used. Install a vapor wick in the cup and fill with solvent to the bottom of the notches in the inner wick. Place the cup in the chamber base recess, align the vapor wick openings with the viewing tubes, andreplace 'the upper assembly. Take care that the guide pins properly engage matching holes in the thermal block and that the matching surfaces of the base and block are clean. Be careful not to allow the thermistor beads to touch the cup or wicks as they may be bent out of alignment. Turn on the thermostat and allow the temperature of the sample chamber to reach equilibrium at 37"C. NOTE 5 - - I f the block is at room temperature, 2 to 3 h will be

required. To avoid such delay, it is desirable to always leave the thermostat switchin the "on" position, if the chamber is at equilibrium and is opened briefly, 30 to 45 rain will generallybe required before temperature stabilization is regained. The exchange or refilling of syringesdoes not necessitateany waitingperiod. 7.3 Thoroughly rinse all syringes with the solvent being used and allow to dry. 7.4 Fill the syringes from guide tubes "5" and "6" with the solvent. Fill the syringes for guide tubes "1" through "4" with the standard solutions in order of increasing concentration. 7.5 Insert the syringes into the thermal block, keeping the guide pins pointed away from the probe. Turn on the "Null Detector" switch (Note 6). Set the sensitivity control to sufficient gain so that a 1.0-fi shift in the "Dekastat" produces one major division shift of the meter needle. NOTE 6--No measurements should be attempted until the "Null Detector" switchhas been on for at least 30 min. 7.6 Turn on the "Bridge" switch and turn the "T-AT" switch to "T". Approximately zero the meter with the "T" potentiometer and observe the drift of the needle. If the solvent chamber is at equilibrium, the needle should not drift more than 1 to 2 mm during one complete heating cycle; a steady drift to the right indicates that the chamber is still warming up; if "T" is stable, switch the selector to the "AT" position. 7.7 While observing the thermistors in the viewing mirror, lower the syringe in position "5", by rotating the knurled collar of the holder fully clockwise. With the end of the needle directly above the reference thermistor, turn the feed screw and rinse the thermistor with about 4 drops of solvent. Finally, deposit a drop of solvent on the ther~aistor bead and raise the syringe by rotating the knufled collar in a counterclockwise direction. Rinse the sample thermistor with solvent from syringe "6" and apply a drop approximately the size of the drop on the reference thermistor. Depress the zero 366

Relative Molecular Mass (Molecular Weight) Range

Repeatability, g/mot

Reproducibility. g/tool

245 to 399 400 to 599 600 to 800

5 12 30

14 32 94

button, and zero the meter with the "Zero" control. Set the decade resistance to zero, and balance the bridge using the "Balance" control. Repeat the balancing of the bridge with fresh drops of solvent on each thermistor to assure a good reference zero. 7.8 Lower syringe " l " and rinse the sample thermistor with 3 to 4 drops of solution, finally applying one drop to the bead. Start the stop watch. Center the meter by means of the decade dials and take readings at l-min intervals until two successive readings do not differ by more than 0.01 ohm. Record the AR value, estimating to the nearest 0.01 fl from the meter. Record the time required to reach this steady state, and use this time for all subsequent readings for thc solvent used. 7.9 Upon completing each series of sample readings, rinse the sample thermistor with solvent, deposit a drop, and recheck the zero point. The meter should reproduce the original indication within 0.5 mm. If the needle shows a negative deflection, the sample thermistor should be rinsed again. If it shows a positive deflection, the drop on the reference thermistor should be replaced. 7.10 Plot the AR values for each concentration of standard against the molarity of the standard for the solvent used. NOTE 7--The calibrationmust be repeated for each of the solventsto be employedand separateworkingcurvesconstructed. Recalibrationis necessaryeach time a new batch of solvent is put into use.

8. Procedure 8.1 Select the solvent to be used and fill the solvent cup as described in 7.2. Weigh into a 25-mL volumetric flask the amount of sample suggested in the following table (Note 5): Estimated Relative Molecular Mass

Sample Size, g

Less than 200 200 to 500 500 to 700 700 to 1000

0.3 0.3 to 0.6 0.6 to 0.9 0.9 to 1.3

Record the weight to the nearest 0.1 mg and dilute to volume with solvent. NOTE 8 - - I f the amount ofsample is limited, weigh the sample into a 5 or I-mL volumetric flask, using one-fifth or one twenty-fifth respectively of the amount indicated in the table. Weighto the nearest 0.001

mg usinga microbalance. 8.2 Fill syringes "5" and "6" with solvent and fill one of the remaining syringes with the sample solution. With the sample chamber at thermal equilibrium, balance the bridge to establish the reference zero as described in 7.6 and 7.7. 8.3 Rinse the sample thermistor with 3 or 4 drops of the sample solution and deposit 1 drop on the thermistor. Start the stop watch. Center the meter with the decade dials and record AR at the time interval determined during the standardization for the solvent being employed (7.8). When

~) D 2503 running a series of samples, check the zero point frequently as described in 7.9. 8.4 Using the appropriate calibration curve, obtain the molarity corresponding to the observed AR value.

apparatus under constant operating conditions on identical test material, would in the long run, in the normal and correct operation of the test method, exceed the values shown in Table l only in one case in twenty. I l.l.2 ReproducibilitymThe difference between two single and independent results, obtained by different operatots, working in different laboratories on identical test material, would in the long run, in the normal and correct operation of the test method, exceed the values shown in Table l only in one case in twenty. I I. 1.3 The precision was not obtained in accordance with Committee D-2 Research Report RR-D-2-1007, "Manual on Determining Precision Data for ASTM Methods on Petroleum Products and Lubricants.''4 11.3 Bias--Bias for this method has not been determined.

9. Calculation 9.1 Calculate the relative molecular mass (molecular weight) of the sample as follows: Relative Molecular Mass (molecularweight) = c/m where: c = concentration of sample solution, g/L and m = molarity of solution, as determined in 8.4.

10. Report 10.1 Report the result to the nearest whole number.

12. Kcywords 12.1 hydrocarbons; molecular weight; osmometer; relative molecular mass; thermoelectric measurement; vapor pressure

11. Precision and Bias 11.1 Precision--The precision of this test method as obtained by statistical examination of interlaboratory test results is as follows: I1.1.1 Repeatability--The difference between successive test results obtained by the same operator with the same

4 Annual Book of ASTM Standards, Vol 05,03.

The American Society for Testing and Materials takes no position respectmg the vafldity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the vafidity of any such patent rights, and the risk of infringement of such rights, ere entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and ff not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend, ff you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103.

367

Designation: D 2504-88 (Reapproved 1993)el

An American National Standard

Standard Test Method for Noncondensable Gases in C 2 and Lighter Hydrocarbon Products by Gas Chromatography 1 This standard is issued under the fixed designation D 2504; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reappmval. A superscript epsilon (~) indicates an editorial change since the last revision or reapproval. o NoTE--Keywords were added editorially in October 1993.

1. Scope 1.1 This test method covers the determination of hydrogen, nitrogen, oxygen, and carbon monoxide in the parts per million volume (ppmv) range in C2 and lighter hydrocarbon products. This test method should be applicable to light hydrocarbons other than ethylene, but the test program did not include them. 1.2 The values stated in acceptable metric units are to be regarded as the standard. The values in parentheses are for information only. 1.3 This standard does not purport to address all of the

safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For some specific hazard statements, see Notes 3, 4, and 5. 2. Referenced Documents

2.1 A S T M Standards: D2505 Test Method for Ethylene, Other Hydrocarbons, and Carbon Dioxide In High-Purity Ethylene by Gas Chromatography 2 E 260 Practice for Packed Column Gas Chromatography 3 F 307 Practice for Sampling Pressurized Gas for Gas Analysis 4 2.2 Other Standard." 5 Compressed Gas Association Booklets G-4 and G-4.1 on the use of oxygen. 3. Summary of Test Method 3.1 The sample is separated in a gas-solid chromatographic system using molecular sieves as the solid adsorbent. The concentration of the gases to be determined is calculated from the recorded peak heights or peak areas. Argon can be used as a cartier gas for the determination of hydrogen in concentrations below 100 ppmv. Argon, if present in the sample, interferes with oxygen determination. J This test method is under the jurisdiction of ASTM Committee I)-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.D on Hydrocarbons for Chemical and Special Uses. Current edition approved Oct. 31, 1988. Published December 1988. Originally published as D 2504 - 66 T. Last previous edition D 2504 - 83~1. 2 Annual Book of ASTM Standards, Vol 05.01. 3 Annual Book of ASTM Standards, Vol 14.01. 4 Annual Book of ASTM Standards, Vol 10.05. 5 Available from Compressed Gas Association, 1253 Jefferson Davis Highway, Arlington, VA, 22202.

4. Significance and Use 4.1 The presence of trace amounts of hydrogen, oxygen, and carbon monoxide can have deleterious effects in certain processes using hydrocarbon products as feed stock. This test method is suitable for setting specifications, for use as an internal quality control tool and for use in development or research work. 5. Apparatus 5.1 Chromatograph--Any chromatographic instrument having either a thermal conductivity or ionization detector with an overall sensitivity sufficient to detect 2 ppmv or less of the compounds listed in the scope, with a peak height of at least 2 mm without loss of resolution. 5.2 Detectors--Thermal Conductivity--If a methanation reactor is used, a flame ionization detector is also required. To determine carbon monoxide with a flame ionization detector, a methanation reactor must be inserted between the column and the detector and hydrogen added as a reduction gas. Details on the preparation and use of the reactor are given in Appendix X I. 5.3 Constant-Volume Gas Sampling Valve. 5.4 Column--Any column or set of columns that is capable of resolving the components listed in the scope can be used. Copper, stainless steel, or aluminum tubing may be used. The columns chosen must afford a resolution such that the depth of the valleys ahead of the trace peak is no less than 50 % of the trace peak height. 5.5 Recorder--A recorder with a full-scale response of 2 s or less and a maximum rate of noise of :t:0.3 % of full scale. 5.6 Oven--The oven used for activating molecular sieves must be maintained at 260 to 288"C (500 to 550"F) and should be designed so that the gases may be displaced continuously by a stream of inert gas. The oven may be a thermostated piece of l-in. pipe about 0.3m (1 ft.) in length. Electrical heating tapes or other means may be used for heating provided the heat is distributed uniformly. NOTE i--The use of copper tubing is not recommended with samples containing acetylene as this could lead to the formation of potentially explosivecopper acetylide. 6. Reagents and Materials 6.1 Molecular Sieves, 5A, 13A, or 13X--Any mesh sizes can be used so long as sensitivity and resolution are maintained (see Note 2). If a 40 to 60-mesh sieve size is desired, but is not available, it may be prepared as described in 8.1.

368

~

D 2504

6.2 CoconutCharcoal, 30 to 60-mesh sieve size (optional). NOTE 2--Columns that have been found to give the desired separation include a l-m by 3.175-ram outside diameter column of 100 to 120 mesh 5A molecular sieve, a 3-m by 6.35-mm outside diameter column of 40 to 60-mesh 5A sieve, and a 7.7-m by 6.35-mm outside diameter column with 13A or 13X sieve in the first 7.4 m and charcoal in the 0.3

is always preferable not to dilute the first sample. NOTE 8--Synthetic standard samples should be prepared as described in Test Method D 2505.

9.3 Inject a known volume of one of the standard samples, using a minimum of 1 mL for detecting 2 ppmv.

m.

NOTE 9--Use of a reverse-flowarrangement will facilitate removal of heavier gases and decrease the elapsed time of analysis.

6.3 Gasesfor Calibration--Pure or research grade hydrogen, oxygen, nitrogen, and carbon monoxide will be needed to prepare synthetic standard samples as described in Test Method D 2505. (Warning--See Notes 4 and 5.) Certified calibration blends are commercially available from numerous sources and can be used as the synthetic standard samples. NOTE 3: Warning--Flammable gases. Hazardous pressure. See Annexes AI.I through AI.5. NOTE 4: Warning--Flammable. Poison. Harmful if inhaled. Dangerous when exposed to flame. See Annex A 1.5. NOTE 5: Warning--Hazardous pressure. See Annex A I.2. 6.4 CarrierGases--Argon or helium. NOTE 6--Practices E 260 contains information that will be helpful to those using this test method.

9.4 Record all of the desired peaks on each of the synthetic blends prepared. 9.5 Prepare a chart for each compound, plotting the peak height of the compound or peak area of the compound against the concentration of the compounds in ppmv. The peak area can be determined by any method that meets the precision requirements of Section 12. Methods found to be acceptable include planimetering, integration (electronic or mechanical or computer processing), and triangulation. 10. Procedure

10.1 Connect the sample cylinder containing a gaseous sample to the gas sample valve with a metal tube and allow the sample to flow from the sample tube for about 1/2 min. at a rate of 70 to 100 mL/min. 10.2 Inject into the instrument the same volume of sample as used for calibration, (pressure of sample and calibration gas must be the same in the sample loop) and record the peak areas or peak heights desired.

7. Sampling 7.1 Samples shall be supplied to the laboratory in highpressure sample cylinders, obtained using the procedures described in Practice F 307 or similar methods. 8. Preparation of Apparatus

8.1 Chromatographic Column Packing--Crush in a porcelain mortar and sieve to 40 to 60-mesh size about 200 g of molecular sieves 5A in order to have enough for several columns. All work of preparing molecular sieves and packing columns with this material shall be done rapidly, preferably under a blanket of dry nitrogen in order to minimize moisture absorption. Heat the screened molecular sieves in an oven at 274 + 14"C (525 _+ 25"F) for 24 h purging with dry nitrogen at a rate of about 5 mL/min during this time. The nitrogen rate is not critical and can be measured by any convenient means such as an orifice meter, rotameter, manometer, etc. Do not use a wet test meter. 8.2 Chromatographic Column--Purge the metal tubing with dry nitrogen. Insert a small amount of glass wool in the end. Fill rapidly with the screened and activated molecular sieves, adding the latter in l-g increments. Vibrate the column, adding additional sieves during this period, if necessary, to fill. Insert a small amount of glass wool in the top. Bend the column in the shape required to fit the chromatographic instrument. Regenerate the column in the oven in the same manner as described in 8.1 whenever the oxygen is not completely separated from the nitrogen peak.

11. Calculation 11.1 From the peak height or area of the compound in the sample, determine the moles per million of the compound using the charts prepared in calibration. A typical characterization showing hydrogen, oxygen, and nitrogen in ethylene is presented in Fig. 1. 12. Precision and Bias

12.1 The precision of this test method as determined by statistical examination of interlaboratory results is as follows: 12.1.1 Repeatability--The difference between successive test results, obtained by the same operator with the same apparatus under constant operating conditions on identical test material would, in the long run, and in the normal and correct operation of the test method, exceed the following values only in one case in twenty: Component Oxygen

Nitrogen Carbon Monoxide Hydrogen

Range, ppmv

Repeatability, ppmv

10-150 100-700 0-20 0-15

15 72 3 2

12.1.2 Reproducibility--The difference between two single and independent results obtained by different operators working in different laboratories on identical test material would, in the long run, and in the normal and correct operation of the test method, exceed the following values only in one case in twenty:

9. Calibration 9.1 Bring the equipment and column to equilibrium and maintain a constant carrier gas rate and temperature. NOTE 7--Carrier gas rates of 36 to 60 mL/min and temperatures of 50 to 60"C have been used successfully. 9.2 Prepare at least three synthetic standard samples containing the compounds to be determined over the range of concentration desired in the products to be analyzed, using the pure gases or the certified blend. For the preparation of the second, third, and following calibration samples it

Component Oxygen Nitrogen Carbon Monoxide Hydrogen

369

Range, ppmv 10-150 100-1000 0-20 0-15

Reproducibility, ppmv 155 875 7 8

~

D 2504

45.28

Z

04

40.26

35.

E3 C,J Q

SO. 2 i

25. i9

L

20. t7 0.00

,

I 2.00

,

I 4.0t

FIG. 1

,

1 E.0i

1

I 8.02

Typical Chromatogram

,

I t0.0S

,

1

t2.03

,

I

t4.04

!

i6.05

for H y d r o g e n , O x y g e n a n d Nitrogen

NOTE 10--The committee believes the methods for oxygen and nitrogen are better than the precision would indicate, and that the poor reproducibilityis attributable to the difficultyof excludingair from these samples. Precise results are heavily dependent upon extreme care in sampling and handling. The use of continuous analyzers is preferred, and is recommended whenever circumstances permit.

12.2 BiasmThe bias of the procedure in this test method has not yet been determined but it is now under consideration by the responsible committee. 13. Keywords 13.1 carbon dioxide; ethane; ethylene; gas chromatography; hydrocarbons; methane; nitrogen

ANNEX

(Mandatory Information) AI. PRECAUTIONARY S T A T E M E N T S

A1.2 Compressed Gases

AI.I Flammable Gas Keep away from heat, sparks, and open flame. Use with adequate ventilation. Never drop cylinder. Make sure cylinder is supported at all times. Keep cylinder out of sun and away from heat. Always use a pressure regulator. Release regulator tension before opening cylinder. Do not transfer cylinder contents to another cylinder. Do not mix gases in cylinder. Keep cylinder valve closed when not in use. Do not inhale. Do not enter storage areas unless adequately ventilated. Stand away from cylinder outlet when opening cylinder valve. Keep cylinder from corrosive environment. Do not use cylinder without label. Do not use dented or damaged cylinder. For technical use only. Do not inhale.

Keep container closed. Use with adequate ventilation. Do not enter storage areas unless adequately ventilated. Always use a pressure regulator. Release regulator tension before opening cylinder. Do not transfer to cylinder other than one in which gas is received. Do not mix gases in cylinders. Do not drop cylinder. Make sure cylinder is supported at all times. Stand away from cylinder outlet when opening cylinder valve. Keep cylinder out of sun and away from heat. Keep cylinder from corrosive environment. Do not use cylinder without label. Do not use dented or damaged cylinder. For technical use only. Do not use for inhalation purposes.

370

(@) D 2504 AI.3 Hydrogen Danger--Extremely flammable gas under pressure. Keep away from heat, spark, and open flame. Use with adequate ventilation. Never drop cylinder. Make sure cylinder is supported at all times. Keep cylinder out of sun and away from heat. Always use a pressure regulator. Release regulator tension before opening cylinder. Do not transfer cylinder contents to another cylinder. Do not mix gases in cylinder. Keep cylinder valve closed when not in use. Do not inhale. Do not enter storage areas unless adequately ventilated. Stand away from cylinder outlet when opening cylinder valve. Keep cylinder from corrosive environment.

before opening cylinder valve. All equipment and containers used must be suitable and recommended for oxygen service. Never attempt to transfer oxygen from cylinder in which it is received to any other cylinder. Do not mix gases in cylinders. Do not drop cylinder. Make sure cylinder is secured at all times. Keep cylinder valve closed when not in use. Stand away from outlet when opening cylinder valve. For technical use only. Do not use for inhalation purposes. Keep cylinder out of sun and away from heat. Keep cylinder from corrosive environment. Do not use cylinder without label. Do not use dented or damaged cylinders. See Compressed Gas Association booklets G-4 and G-4.1 for details of safe practice in the use of oxygen.

A1.4 Oxygen Keep oil and grease away. Do not use oil or grease on regulators, gauges or control equipment. Use only with equipment condition for oxygen service by carefully cleaning to remove oil, grease and other combustibles. Keep combustibles away from oxygen and eliminate ignition sources. Keep surfaces clean to prevent ignition or explosion, or both, on contact with oxygen. Always use a pressure regulator. Release regulator tension

A1.5 Carbon Monoxide Harmful or fatal if inhaled. Dangerous when exposed to flame. Keep away from heat, sparks, and open flame. Use with adequate ventilation. Use fume hood whenever possible. Avoid build-up of vapor and eliminate all sources of ignition, especially nonexplosion proof electrical apparatus and heaters. Avoid breathing.

371

(~ D 2504

APPENDIX

(Nonmandatory Information) X1. PREPARATION OF METHANATION REACTOR XI.I Scope X I.I.I This method describes the preparation of a methanation reactor to convert carbon monoxide and carbon dioxide to methane, which can then be determined using a flame ionization detector at levels less than 1 ppm.

sorb. Warm the mixture to 650C on a hot plate and evaporate the methanol with constant stirring, until the mixture appears dry. The resultant catalyst is subsequently reduced in the hydrogenation tube during instrument preparation.

X1.2 Significance and Use X 1.2.1 The use of a flame ionization detector to enhance the detection limits for carbon monoxide and carbon dioxide is made possible by conversion of these gases to methane.

X1.3 Apparatus XI.3.1 Tubing, 152.4 mm (6-in.) of 6.35 mm (l/4-in.) stainless steel. XI.3.2 Aluminum blockmlOI.6 by 152.4 by 15.8 mm (4-in. by 6-in. by %-in.) drilled to accept a I/4-in. tube snugly. XI.3.3 Cartridge heaterD175 W with variable autotransformer. X 1.3.4 Thermocouple sensorDchromel alumel. NOTE X l.l--Commercial instruments performingthe determination in compliancewith this procedure are available.

XI.4 Reagents and Materials X 1.4.1 Insulation. X 1.4.2 Harshaw methanation catalyst-Ni-104t, I00 to 120 mesh, or catalyst prepared as in XI.5. Xl.5 Catalyst Preparation X 1.5. I Hydrogenation catalyst: Prepare by weighing 20 +_ 0.1 g of nickel nitrate hexahydrate into a 100-mL beaker. Add 40 mL of methanol. Weigh 20 _ 0.1 g of Chromosorb "P" into an evaporating dish. After the nickel nitrate crystals have dissolved, slowly pour the solution over the Chromo-

X1.6 Procedure X 1.6.1 Using glass wool as a retainer, pack the 152.4 mm (6-in.) by 6.35 mm (l/4-in.) stainless tube 38.1 mm (1.5-in.) from either end with catalyst. Allowing 38. l mm (1.5-in.) of space at each end of the tube insures failure to produce a highly toxic compound, nickel-carbonyl. XI.6.2 The aluminum block should have three holes drilled in it. One hole should be drilled through the block, lengthwise, in the center of the end, 6.35 mm (l/4-in.) in diameter. Another hole should be drilled on either side of the center. Its dimensions should be 50.8 by 9.53 mm (2-in. by 0.375-in.) in diameter. This hole will accept the cartridge heater. The third hole should be 50.8 mm (2-in.) long and 3.18 mm (I/s-in.) in diameter and on the opposite side of center as the cartridge heater. This will accept the thermocouple sensor. X1.6.3 Place the packed tube through the block so that the ends extend equally from either end of the block. Place the cartridge heater in the block, wrap the system with insulation, and place the therrnocouple in the 3.18 mm (l/8-in.) hole. Use only stainless steel connectors and attach one end of the 6.35 mm (l/4-in.) packed tube to detector inlet. Attach the discharge end of the chromatographic column to the other end of the reactor through a tee connector. The tee is provided in order to introduce 30 mL/min, of hydrogen to the methanator. X 1.6.4 After setting the hydrogen flow, connect the heater to a variable autotransformer. The setting should be approximately 55. Allow the catalyst to condition for 24 h at 300oc. Normal operating temperature for the methanator should be 325 + 250C.

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reepproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend, ff you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103.

372

Designation:D2505-88 (Reapproved1993)

An American National Standard

Standard Test Method for Ethylene, Other Hydrocarbons, and Carbon Dioxide in High-Purity Ethylene by Gas Chromatography 1 This standard is issued under the fixed designation D 2505; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (E) indicates an editorial change since the last revision or reapproval. ~ NorE--Keywords were added editorially in October 1993.

phosphoramide (HMPA) column. Acetylene is determined by using, in series, a hexadecane column and a squalane column. Carbon dioxide is determined using a column packed with activated charcoal impregnated with a solution of silver nitrate in fl,B'-oxydipropionitrile. Columns other than those mentioned above may be satisfactory. (see 5.3.) Calibration data are obtained using standard samples containing the impurities, carbon dioxide, methane, and ethane in the range expected to be encountered. Calibration data for acetylene are obtained assuming that acetylene has the same peak area response on a weight basis as methane. The acetylene content in a sample is calculated on the basis of the ratio of peak area of the acetylene peak to the peak area of a known amount of methane. Calculations for carbon dioxide, methane, and ethane are carded out by the peak-height measurement method.

1. Scope I. 1 This test method covers the determination of carbon dioxide, methane, ethane, acetylene, and other hydrocarbons in high-purity ethylene. Hydrogen, nitrogen, oxygen, and carbon monoxide are determined in accordance with Test Method D 2504. The percent ethylene is obtained by subtracting the sum of the percentages of the hydrocarbon and nonhydrocarbon impurities from 100. The method is applicable over the range of impurities from I to 500 parts per million volume (ppmV). 1.2 This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address all of the safety problems associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For some specific hazard statements, see Notes 8 through 9. 1.3 The values stated in acceptable metric units are to be regarded as the standard. The values in parentheses are for information only. 2. Referenced Documents

2.1 A S T M Standards: D 2504 Test Method for Noncondensable Gases in C2 and Lighter Hydrocarbon Products by Gas Chromatography 2 D4051 Practice for Preparation of Low-Pressure Gas Blends 3 E 260 Practice for Packed Column Gas Chromatography 4 F 307 Practice for Sampling Pressurized Gas for Gas Analysis5 3. Summary of Test Method 3.1 The sample is separated in a gas chromatograph system utilizing four different packed chromatographic columns with helium as the carrier gas. Methane and ethane are determined by using a silica gel column. Propylene and heavier hydrocarbons are determined using a hexamethyl' This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.D on Hydrocarbons for Chemical and Special Uses. Current edition approved Oct. 31, 1988. Published December 1988. Originally published as D 2505 - 66 T. Last previous edition D 2505 - 83. 2 Annual Book of ASTM Standards, Vol 05.01. 3 Annual Book of ASTM Standards, Vol 05.02. 4 Annual Book of ASTM Standards, Vol 14.01. s Annual Book of ASTM Standards, Vol 10.05.

373

4. Significance and Use 4.1 High-purity ethylene is required as a feedstock for some manufacturing processes, and the presence of trace amounts of carbon dioxide and some hydrocarbons can have deleterious effects. This method is suitable for setting specifications, for use as an internal quality control tool and for use in development or research work. 5. Apparatus 5.1 Any chromatographic instrument with an overall sensitivity sufficient to detect 2 ppmV or less of the compounds listed with a peak height of at least 2 ram without loss of resolution. 5.2 Detectors--Thermal Conductivity--If a methanation reactor is used, a flame ionization detector is also required. To determine carbon dioxide with a flame ionization detector, a methanation reactor must be inserted between the column and the detector and hydrogen added as a reduction gas (see Test Method D 2504, Appendix X l). 5.3 Column--Any column or set of columns can be used that separates carbon dioxide, methane, acetylene and Ca and heavier compounds. There may be tailing of the ethylene peak but do not use any condition such that the depth of the valleys ahead of the trace peak is less than 50 % of the trace peak height. (See Fig. 3 for example.) 5.4 Recorder--A recorder with a full-scale response of 2 s or less and a maximum rate of noise of __.0.3 % of full scale. 5.5 Gas-Blending ApparatusmA typical gas-blending apparatus is shown in Fig. 1. A high-pressure manifold equipped with a gage capable of accurately measuring eth-

~@) D 2505 6.7 Acetone. NOTE 6--Extremely Flammable. See Annex A 1.1. 6.8 Gases for Calibration~Pure or research grade carbon dioxide, methane, ethane, acetylene, ethylene, propane, and propylene. Certified calibration blends are commercially available from numerous sources and may be used. NOTE 7: Warning--Flammable Gases, Hazardous Pressure. See Annexes AI.2 and AI.3.

glend C y l i n d e r

Pressure Gau'Je

6.9 Methanol. NOTE 8: W a r n l n g m F l a m m a b l e . Vapor Harmful. See A n n e x AI.4.

To Vacuum P.mp

NOTE 9--The use of copper tubing is not recommended with samples containing acetylene as this could lead to the formation of potentially explosivecopper acetylide.

To pressure regulated source of Ethvlene

~snometer

revel inq

7. Sampling 7.1 Samples should be supplied to the laboratory in high pressure sample cylinders, obtained using the procedures described in Practice F 307, or similar methods.

~ulb

FIG. 1

Gas-Blending Manifold

8. Preparation of Apparatus 8.I Silica Gel Column--Dry the silicagel in an oven at

ylene pressures up to 3.4 MN/m 2 gage (500 psig) is required. Other types of gas-blending equipment, such as described in Practice D 405 l, can be used. NoT~. I--ASTM Practices E 260, contains information that will be helpful to those using this method. 6. Reagents and Materials 6.1 Copper or Aluminum, or Stainless Steel Tubing, 6.4-ram (I/4-in.) outside diameter, and nylon tubing, 3.2mm (m/s-in.) outside diameter. 6.2 Solid Supports--Crushed firebrick or calcined diatomaceous earth, such as Chromosorb p,6 35 to 80-mesh and 80 to 100-mesh. Other supporting materials or mesh sieves can be satisfactory. 6.3 Active Solids~Activated carbon, 30 to 40-mesh, 7 silica gel, 100 to 200-mesh. s Other sizes may be satisfactory. 6.4 Liquid Phases--Hexamethylphosphoramide (HMPA9), hexadecane. 9 Squalene, 9 silver nitrate, and #,/V-oxydipropionitrile) ° Other liquid phases may be satisfactory. NOTE 2: Warning--Combustible solvents. See Annex AI.7. NOTE 3: Warning--HMPA may be harmful if inhaled. Causes irritation. A potential carcinogen (lungs). See Annex AI.5. 6.5 Helium. NOTE 4: Warning--Compressed Gas, Hazardous Pressure. See Annex A !.2. 6.6 Hydrogen. NOTE 5: Warning--Flammable Gas, Hazardous Pressure. See Annex AI.6. 6 Available from the Celite Division, Johns Mansville Co., New York, NY. A fraction sieved in the laboratory to 30 to 40 mesh from medium activity charcoal, 20 to 60 mesh, sold by Central Scientific Co., 1700 Irving Park Road, Chicago, IL 60613, has been found satisfactory for this purpose. s Silica gel Code 923 available from the Davison Chemical Co., Baltimore, Md. 21203, has been found satisfactory for this purpose. 9 Available from the Fisher Scientific Co., St. Louis, MO. io ~,/V-oxydipropionitrile, sold by Distillation Products Industries, Division of Eastman Kodak Co., Rochester, NY, has been found to be satisfactory.

374

204"C (400*F) for 3 h, cool in a desiccator, and store in screw-cap bottles.Pour the activated silicagel into a 0.9-rn (3-ft)length of 6.4-ram (t/4-in.)outside diameter copper or aluminum tubing plugged with glasswool at one end. Tap or vibratethe tube while adding the silicagel to ensure uniform packing and plug the top end with glass wool. Shape the column to fitinto the chromatograph. 8.2 Silver Nitrate--B,/3'-Oxydipropionitrile--Activated Carbon Column--Weigh I0 g of #,#'-oxydipropionitrileinto a brown 125-mL (4-oz) bottle. Add 5 g of silver nitrate (AgNO3) crystals.With occasionalshaking, dissolveas much AgNO3 as possible,and allow the bottleto stand overnightto ensure saturation. Prepare this solution fresh, as required. Without disturbing the crystalsat the bottom of the bottle, weigh 2.5 g of supernatant AgNO3 solution into a 250-mL beaker and add 50 m L of methanol. While stirringthis mixture, slowly add 22.5 g of activated carbon. Place the beaker on a steam bath to evaporate the methanoL When the impregnated activatedcarbon appears to be dry, remove the beaker from the steam bath and finishdrying in an oven at I00 to 110*C for 2 h. Plug one end ofa 4-ft(l.2-m) length of 6.4-ram (V4-in.)outsidediameter aluminum or stainlesssteel tubing with glass wool. Hold the tubing verticallywith the plugged end down and pour freshlydried column packing into it,vibratingthe column during fillingto ensure uniform packing. Plug the top end with glass wool and shape the tubing so that it may be mounted conveniently in the chromatograph. 8.3 Hexamethylphosphoramide Column (HMPA)mDry the 35 to 80-mesh inert support at 204"C (400*F). Weigh 75 g into a wide-mouth 500-mL (16-oz) bottle. Add 15 g of H M P A to the inert support and shake and rollthe mixture until the support appears to be uniformly wet with the HMPA. Pour the packing into a 6-m (20-ft) length of 6.4-ram (V4-in.) outside diameter copper of aluminum tubing plugged at one end with glass wool. Vibrate the tubing while filling to ensure more uniform packing. Plug the top end of the column with glass wool and shape the column to fit into the chromatograph.

~

D 2505

Suggested Composition of a Concentrate of Impurities Used in Preparing Standard Mixtures for Calibration Purposes

with high-purity ethylene in a ratio of approximately 1:4000. This can be done by adding the calculated amount of the concentrate and high purity ethylene to an evacuated cyclinder using the gas-blending apparatus (Fig. l). Use a source of high-pressure, high-purity ethylene equipped with a needle valve and a pressure gage capable of accurately measuring the pressure of the blend as the ethylene is added to the cylinder containing the concentrate. Add the calculated amount of ethylene; warm one end of the cylinder to ensure mixing of the blend. Allow the temperature to reach equilibrium before recording the final pressure on the cylinder. Prepare at least three calibration samples containing the compounds to be determined over the range of concentration desired in the products to be analyzed.

TABLE 1

Component

Percent

Carbon dioxide Methane Ethane Propylene

10 45 25 20

8.4 Hexadecane-Squalane Column--Dissolve 30 g of hexadecane into approximately 100 mL of acetone. Add 70 g of 80 to 100-mesh inert support. Mix thoroughly and pour the mixture into an open pan for drying. The slurry should be stirred during drying to ensure uniform distribution. When the acetone has evaporated, add a portion of the packing to a 7-m (25-ft) length of 3.2-ram 0/a-in.) outside diameter nylon tubing which has been plugged at one end with glass wool. Vibrate the column while filling to ensure more uniform packing. Fill the column with packing to only 4 m (15 ft) of the length of the column. Fill the remainder of the column with squalane packing prepared in the same manner as the hexadecane packing. Plug the open end of the tubing with glass wool and shape the column to fit into the chromatograph with the hexadecane portion of the column at the front end of the column. The column shall be purged under test conditions (no sample added) until a constant baseline is obtained.

NOTE 11: Precaution--As a safety precaution, use a manifold and fittings such as valves and gages that will withstand the pressure encountered. 9.2 Calculation of Composition of Standard Mixtures-Calculate the exact ratio of the concentrate dilution with ethylene by correcting the pressure of the ethylene added for the compressibility of ethylene (Table 2). Multiply the dilution ratio or factor by the percentage of each component present in the original concentrate (Table l). These calculations give the amount of each component that has been added to the high-purity ethylene blend stock. The actual composition of the final blend must be ascertained by making corrections for the impurities present in the highpurity ethylene used for the blend stock. The amount of correction is determined by making chromatograph runs on the high-purity ethylene and measuring the peak heights of the impurities. These peak heights will be used in adjusting the calibration factors described in 9.3. Since peak height is very sensitive to changes in conditions, it is extremely important in correlating peak heights obtained in making calibrations, calibration adjustments, and final impurity determinations that these values be obtained under the same GLC column operating conditions in all cases. 9.3 Determination of Calibration Factors--Chromatograph the standard blend and the high-purity ethylene blend stock by each of the procedures given in Section 10. 9.3.1 Calculate calibration factors for carbon dioxide, methane, ethane, propylene, and heavier hydrocarbons as follows: F = C/(S - B) (1)

NOTE 10--Columnsmade with liquid phases listed above were used satisfactorilyin cooperativework. Other columns may be used (see 5.3). 9. Calibration 9.1 Preparation of Standard Mixtures." 9.1.1 Preparation of Concentrate--Prepare a concentrate of the impurities expected to be encountered. A certified calibration blend containing the expected impurities can be obtained and used as the concentrate. An example of a satisfactory concentrate is given in Table 1. The concentrate can be prepared using the gas blending manifold as shown in Fig. 1 or using a similar apparatus as follows: Evacuate the apparatus and add the components in the order of increasing vapor pressure; that is, propylene, carbon dioxide, ethane and methane. Record the increase in pressure on the manometer as each component is added. Close the reservoir and evacuate the manometer after each addition. 9.1.2 Dilution of Concentrate--Dilute the concentrate

TABLE 2 Supercompressibility of Ethylene NOTE--The trace component, A, in parts per million volume of finished blend, is determined as follows: A = [(1 000 000 x Z b x

P=)/(Z= x

P,)] + B

(2)

where: Z a = value of Z for observed partial pressure and temperature of the trace component added, P= = partial pressure of trace component, psia (ram Hg x 0.01934), Zb = appropriate value of Z for final observed temperature and pressure of ethylene blend, PI = final observed pressure (psia) at observed temperature, and B = concentration, mols per million of trace component present in diluent ethylene. For synthetic pressures below 200 psia (1380 kN/m2), Z usage is not significant. Pressure, psia (kN/m 2

Values of Z

absolute)

15*C

20oc

25°C

30oC

350C

40oC

15 (103) 100 (690) 200 (1380) 300 (2068)

0.98 0.95 0.90 0.85

0.99 0.96 0.91 0.86

0.99 0.96 0.92 0.87

0.99 0.96 0.92 0.88

0.99 0.96 0.92 0.89

0.99 0.97 0.93 0.89

375

~ TABLE 3 Methane and Ethane Column packing

silica gel

Column dimensions

0.9 m (3 ft) by 6.4 mm (,/, in.)

Sample volume Carder gas

D 2505 Operating Conditions

Carbon Dioxide

Propylene and Heavier

AgNOs-oxydipropionitdle on support 1.2 m (4 ft) by 6.4 mm (V4 in.)

Acetylene

HMPA on support

hexadecane-squelane on support

6 m (20 ft) by 6.4 mm (V4 in.)

6 m (25 ft) by 3.2 mm (Vs in.)

1 mL

25 mL

1 mL

0.25 mL

helium 20 Ib

helium 10 Ib

helium

Carrier pressure

helium 20 Ib

Temperature

50oC

35°C

30oC

ambient

Detector

thermal conductivity

thermal conductivity

thermal cooductlvity

hydrogen flame ionization

where: F = mol percent per unit of peak height, C = concentration of component added to the high-purity ethylene blend stock, tool %, S = m m peak height of component in standard mixture, and B = mm peak height of component in high-purity ethylene blend stock, mm. 9.3.2 Calculate calibration factor for acetylene as follows: Fa C/(Sa - Ba) (3) where: Fa = weight percent per unit area, C = concentration of methane added to the high-purity ethylene blend stock in weight percent, Sa = area of methane peak in standard mixture, and Ba = area of methane peak in high-purity ethylene blend stock.

mum attenuation or g r e a t e s t sensitivity for maximum peak height. Figure 2 shows a typical chromatogram obtained with the procedure and operating conditions as outlined. Measure the height of each peak from the baseline in millimetres. Both peak height and peak area need to be measured for methane since the area will be used for preparation of an acetylene calibration curve. 10.2 Carbon Dioxide--Typical operating conditions for the analysis for carbon dioxide are given in Table 3. Flush the sample to be analyzed through the gas sample valve on the chromatograph until all extraneous vapor has been purged from the sample loop. Turn the gas valve to introduce the sample into the carrier gas stream. Record the carbon dioxide peak at the greatest sensitivity for maximum peak height. Measure the height of each peak from the baseline in millimetres. NOTE 12--T he elution order for this column is as follows:

:

Material

Approximate Time, rain

Air Methane Carbondioxide

10. Procedure 10.1 Methane and Ethane--Typical operating conditions for the analyses for methane and ethane are summarized in Table 3. Slowly flush the sample to be analyzed through the gas sample valve on the chromatograph until all extraneous vapor has been purged from the sample loop. Turn the gas valve to introduce the sample into the carrier gas stream. Record the deflection of each component peak at the mini-

2 3 7

Ethylene

1I

10.3 Propylene and Heavier--Typical operating conditions for the procedure for propylene and heavier components are given in Table 3. Flush the sample to be analyzed through the gas sample valve on the chromatograph until all the extraneous vapor has been purged from the sample loop.

Propylene

> >

2

m

w

- c

0

FIG. 2

1

2

m

3

LI

S

g

i

~

~

I 1

I~

Typical Chromatogram for Air, Methane, and Ethane

FIG. 3

376

I

,

I

I

I

I

I

I

I

2 3 u 5 6 7 8 9 lO Typical Chromatogram for Propylene

~)

D 2505

Turn the gas valve to introduce the sample into the carrier stream. Record the peaks of each component at maximum sensitivity for maximum peak height. Figure 3 shows a typical chromatograph obtained with the procedure and conditions described. Measure the height of each peak from the baseline as formed by the tailing of the ethylene peak. 10.4 Acetylene--Typical operating conditions for the analysis for acetylene are given in Table 3. Flush the sample to be analyzed through the gas sample valve on the chromatograph until all extraneous vapor has been purged from the sample loop. Operate the gas valve to introduce the sample into the carrier gas stream. Measure the peak areas of the methane and acetylene peaks. Figure 4 shows a typical chromatograph obtained with the procedure and conditions outlined.

where: C = concentration of component, mol %, D ffi peak height of the component, mm, and F ffi calibration factor of component as determined in 11.3.1. 11.2 Acetylene--Calculate the tool percent of acetylene in the sample as follows: C ffi A x Fax (28/26) (5) where: C = concentration of acetylene, tool %, A ffi area of the acetylene peak, and Fa ffi area calibration factor as determined in 6.3.2. 11.3 Ethylene--Calculate the tool percent of ethylene in the sample by adding the concentration of all impurities and subtract from 100.

l l . Calculation 11.1 Carbon Dioxide, Methane, Ethane, Propylene, and HeaviermCalculate the mol percent of each component present in the sample as follows: C-- D x F (4)

12. Precision and Bias

12.1 The precision of this test method as determined by statistical examination ofinterlaboratory results is as follows: 12.1.1 Repeatability--The difference between successive test results, obtained by the same operator with the same apparatus under constant operating conditions on identical test material would, in the long run, and in the normal and correct operation of the test method, exceed the following values only in one case in twenty: Component Ethylene Methane Ethane

Propylene Propane

Acetylene Carbon dioxide

Range 99.80-99.99 mol % 1-150 ppmV 1-1500 ppmV 1-15 ppmV 1-15 ppmV 1-20 ppmV 1-10 ppmV

Repeatability 0.006 tool % 3 ppmV 43 ppmV 3 ppmV 2 ppmV I ppmV I ppmV

12.1.2 Reproducibility----The difference between two single and independent results, obtained by different operators working in different laboratories on identical test material would, in the long run, and in the normal and correct operation of the test method, exceed the following values only in one case in twenty: Component Ethylene Methane

Ethane Ethane

Propylene Propane Acetylene Carbon dioxide

Range 99.80-99.99 tool % 0- i 50 ppmV 0-500 ppmV 500-1500 ppmV 0-15 ppmV 0-15 ppmV 0-20 ppmV 0-10 ppmV

Reproducibility 0.1 mol % 34 ppmV 72 ppmV 290 ppmV 11 ppmV 7 ppmV 6 ppmV 4 ppmV

12.2 B/as--The bias of the procedure in this test method has not yet been determined but is now under consideration by the responsible subcommittee. HINUTES

I

0

I

1

I

2

I

3

I

13. Keywords 13.1 carbon dioxide; ethane; ethylene; gas chromatography; hydrocarbons; methane

q

FIG. 4 TypicalChrornatogramfor Acetylene as a Trace Impurity in Ethylene

377

~) D 2505

ANNEX

(Mandatory Information) A1. PRECAUTIONARY STATEMENTS

AI.I Acetone

Do not use cylinder without label. Do not use dented or damaged cylinder. For technical use only. Do not inhale.

Keep away from heat, sparks, and open flame. Keep container closed. Use with adequate ventilation. Vapors may spread long distances and ignite explosively. Avoid build-up of vapors and eliminate all sources of ignition, especially non-explosion proof electrical apparatus and heaters. Avoid prolonged breathing of vapor or spray mist. Avoid contact with eyes and skin.

A1.4 Methanol May be fatal or cause blindness if swallowed or inhaled. Cannot be made non-poisonous. Keep away from heat, sparks, and open flame. Keep container closed. Avoid contact with eyes and skin. Avoid breathing of vapor or spray mist. Use with adequate ventilation. Do not take internally.

A1.2 Compressed Gas Keep container closed. Use with adequate ventilation. Do not enter storage areas unless adequately ventilated. Always use a pressure regulator. Release regulator tension before opening cylinder. Do not transfer to cylinder other than one in which gas is received. Do not mix gases in cylinders. Do not drop cylinder. Make sure cylinder is supported at all times. Stand away from cylinder outlet when opening cylinder valve. Keep cylinder out of sun and away from heat. Keep cylinder from corrosive environment. Do not use cylinder without label. Do not use dented or damaged cylinder. For technical use only. Do not use for inhalation purposes.

Al.5 Hexamethyl Phosphoramide A potential carcinogen (lung). Avoid breathing vapor or mist. Avoid contact with skin, eyes, and clothing. Use with adequate ventilation. Keep container closed when not in use. Wash thoroughly after handling.

A1.6 Hydrogen Keep away from heat, sparks, and open flame. Use with adequate ventilation. Never drop cylinder. Make sure cylinder is supported at all times. Keep cylinder out of sun and away from heat. Always use a pressure regulator. Release regulator tension before opening cylinder. Do not transfer cylinder contents to another cylinder. Do not mix gases in cylinder. Keep cylinder valve closed when not in use. Do not inhale. Do not enter storage areas unless adequately ventilated. Stand away from cylinder outlet when opening cylinder valve. Keep cylinder from corrosive environment.

A1.3 Flammable Gas Keep away from heat, sparks and open flame. Use with adequate ventilation. Never drop cylinder. Make sure cylinder is supported at all times. Keep cylinder out of sun and away from heat. Always use a pressure regulator. Release regulator tension before opening cylinder. Do not transfer cylinder contents to another cylinder. Do not mix gases in cylinder. Keep cylinder valve closed when not in use. Do not inhale. Do not enter storage areas unless adequately ventilated. Stand away from cylinder outlet when opening cylinder valve. Keep cylinder from corrosive environment.

A1.7 n-Hexadecane Keep away from heat, sparks, and open flame. Keep container closed. Use with adequate ventilation. Avoid breathing vapor or spray mist. Avoid prolonged or repeated contact with skin.

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five yeers and if not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at e meeting of the responsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103.

378

(~l~

Designation: D 2549 - 91

Standard Test Method for Separation of Representative Aromatics and Nonaromatics Fractions of High-Boiling Oils by Elution Chromatography 1 This standard is issued under the fixed designation D 2549; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (0 indicates an editorial change since the last revision or reapproval.

3. Terminology 3.1 Descriptions of Terms Specific to This Standard." 3.1.1 aromatics fraction--the portion of the sample desorbed with the polar eluants. The aromatics fraction may contain aromatics, condensed naphthenic-aromatics, aromatic olefins, and compounds containing sulfur, nitrogen, and oxygen atoms, 3.1.2 nonaromatics fraction--the portion of the sample eluted with n-pentane. The nonaromatics fraction is a mixture of paraffinic and naphthenic hydrocarbons if the sample is a straight-run material. If the sample is a cracked stock, the nonaromatics fraction will also contain aliphatic and cyclic olefins.

1. Scope 1.1 This test method covers the separation and determination of representative aromatics and nonaromatics fractions from hydrocarbon mixtures that boil between 232 and 538"C (450 and 1000°F). Alternative procedures are provided for the separation of 2 g or 10 g of hydrocarbon mixture. NOTE l - - S o m e components may not be eluted from the chromatographic column for some types of samples under the conditions used in this method. NOTE 2 - - T e s t Method D 2007 is an alternative method of separating high-boiling oils into polar compounds, aromatics, and saturates fractions.

1.2 An alternative procedure is provided to handle samples boiling below 232°C (450"F), but whose 5 % point is above 178"C (350°F) as determined by Test Method D 2887. This procedure is given in Annex A 1. 1.3 The values stated in acceptable SI units are to be regarded as the standard. The values given in parentheses are provided for information purposes only. 1.4 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

4. Summary of Test Method 4.1 A weighed amount of sample is charged to the top of a glass chromatographic column packed with activated bauxite and silica gel. n-Pentane is added to the column to elute the nonaromatics. When all of the nonaromatics are eluted, the aromatics fraction is eluted by additions of diethyl ether, chloroform, and ethyl alcohol. 4.2 The solvents are completely removed by evaporation, and the residues are weighed and calculated as the aromatics and nonaromatics fractions of the sample. 5. Significance and Use 5.1 The determination of compound types by mass spectrometry requires, in some instances, a preliminary separation of the petroleum sample into representative aromatics and nonaromatics fractions, as in Test Methods D 2425, D 2786, and D 3239. This test method provides a suitable separation technique for this application.

2. Referenced Documents

2.1 A S T M Standards: D 2007 Test Method for Characteristic Groups in Rubber Extender and Processing Oils and Other PetroleumDerived Oils by the Clay-Gel Adsorption Chromatographic Method2 D2425 Test Method for Hydrocarbon Types in Middle Distillates by Mass Spectrometry2 D 2786 Test Method for Hydrocarbon Types Analysis of Gas-Oil Saturate Fractions by High Ionizing Voltage Mass Spectrometry2 D2887 Test Method for Boiling Range Distribution of Petroleum Fractions by Gas Chromatography2 D3239 Test Method for Aromatic Types Analysis of Gas-Oil Aromatic Fractions by High Ionizing Voltage Mass Spectrometry2

6. Apparatus 6.1 Chromatographic Columns,, as shown in Fig. 1. Different chromatographic columns are provided for the analysis of 2 and 10-g samples. 6.2 Beakers, 100, 250, and 600-mL, inverted-rim type) 6.3 Steam Bath. 6.4 Electric Vibrator, for packing column. 6.5 Weighing Bottles or Erlenmeyer Flasks, 25 and 50 mL.

This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.04 on Hydrocarbon Analysis. Current edition approved March 15, 1991. Published June 1991. Originally published as D 2549 - 66 T. Last previous edition D 2549 - 85 ~, 2 Annual Book of ASTM Standards, Vol 05.02.

7. Reagents and Materials 3 Beakers available from Kontes Glass Co., Vineland, NJ, by ordering "AfitiCreep" beakers and referring to Drawing No. 9413-A.

379

(~ D 2549

200 ML BULB

_,/ 100 ML BULB

28/15 SPHERICAL J O I N T ~ " ~ ~ "

•

O

:E

GLAZED MARKERS

=o

:E =E O 1,O

:E 3E O tD

0 O0 p~

MM OPENING 10 MM ID FOR 2-GRAM SAMPLES 3 MM OPENING 15 MM ID FOR 10-GRAM SAMPLES FIG. 1 Chromatographic Columns

oxidizer, contact with organic material may cause fire. See Annex A2.2.). 7.5 Diethyl Ether, anhydrous, (Warning--Extremely flammable.). The ethyl ether used in this test method should be free of peroxides as determined by the procedure in "Reagent Chemical, American Chemical Society Specifications." 7.6 Ethyl Alcohol, denatured, conforming to Formula 2B of the U.S. Bureau of Internal Revenue (WarningnFlammable.). 7.7 Pressuring Gas, dry air or nitrogen, delivered to the top of the column at a regulated gage pressure of 0 to 2 psi (13.8 kPa) (WarningnCompressed gas.). 7.8 n-Pentane, commercial grade, aromatic-free. Some samples of waxy stocks may not dissolve completely in n-pentane, in which case cyclohexane, commercial grade, aromatic-free, may be substituted for n-pentane (Warning-Extremely flammable liquid.). 7.9 Silica Gel,6 100 to 200-mesh.

7.1 Purity of Reagents--Reagent grade chemicals shall be used in this test. Unless otherwise indicated, it is intended that all reagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, where such specifications are available. 4 Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination. 7.2 Bauxite, 5 20 to 60-mesh. Before use, activate the bauxite by heating at 538"C (1000*F) for 16 h. Transfer the activated material to an airtight container while still hot and protect thereafter from atmospheric moisture. 7.3 Chloroform (Warning--Toxic. May be fatal if swallowed. See Annex A2.1.). 7.4 Cleaning Solution--Chromic- sulfuric acid (Warning--Causes severe burns. A recognized carcinogen, strong 4 "Reagent Chemicals, American Chemical Society Specifications," Am. Chemical Soc., Washington, DC. For suggestions on the testing of reagents not listed by the American Chemical Society, see "Reagent Chemicals and Standards," by Joseph Rosin, D. Van Nostrand Co., Inc., New York, NY, and the "United States Pharmacopeia." .s Bauxite available from Porocel Corp., Little Rock, AR.

6 Silica gel available from W.R. Grace and Co., Davison Chemical Div., Baltimore, MD 21203, by specifying Code 923.

380

~

D 2549

8. Procedure NOTE 3--The procedural details differ depending on the initial boiling point of the sample. If the 5 % point is above 178"C(350"F), but below 232"C (450"F) use procedure described in Annex A1. If above 232"C continue as written depending on amount of sample to be analyzed. Instructions specific for 2-g samples are given in 8.4.1 to 8.4.13, and instructions specific for 10-g samples are given in 8.5.1 and 8.5.8. 8.1 Select the appropriate column, depending on whether 2 or l0 g of sample are to be analyzed. Clean the column with chromic-sulfuric acid, (Warning--Causes severe burns. See Annex A2.2.) followed by distilled or demineralized water, acetone, and dry air or nitrogen. 8.2 Introduce a small plug of glass wool into the column, pressing it firmly into the lower end to prevent the flow of silica gel from the column. 8.3 Clamp the column in a vertical position. Add small increments of silica gel, while vibrating the column along its length, until the tightly packed silica gel extends to the lower mark on the chromatographic column. Continue to vibrate the column and add bauxite until the bauxite layer extends to the upper mark on the chromatographic column. Vibrate the column for an additional 3 min after filling is completed. 8.4 If 2 g of sample are to be analyzed, continue as in 8.4.1, otherwise continue as in 8.5. 8.4.1 If the sample is viscous, warm it with intermittent mixing or shaking until it is completely fluid. Transfer a representative sample (approximately 2 g) to a 25-mL weighing bottle or flask. Determine the weight of the sample to the nearest 1 mg by weighing the flask before and after sample transfer. Add 10 m L of n-pentane (Warning-Extremely flammable liquid.) to the flask and dissolve the sample. If the sample does not dissolve completely in cold n-pentane, warm it in warm water or over a steam bath. If the sample does not dissolve in warm n-pentane, take a fresh sample and substitute cyclohexane for the n-pentane. 8.4.2 Add l0 m L ofn-pentane to the top of the column to prewet the adsorbent. When the liquid level reaches the top of the bauxite bed, transfer the sample solution from the weighing flask to the top of the column. Rinse the flask with three successive 3-mL washes of n-pentane. Add each wash to the top of the column. Then rinse the walls of the column bulb with two 3-mL portions of n-pentane, allowing the liquid level to reach the top of the bauxite bed before adding the next portion. Finally add 35 m L of n-pentane to the column bulb. 8.4.3 Place a 50-mL graduate beneath the column to collect the eluate. The elution rate should be approximately 1 mL/min. NOTE 4--Gas pressure (Warning--Compressed gas.) can be applied to the top of the column as necessary to maintain the elution rate at approximately 1 mL/min. If the correct pressure setting is known from previous runs, gas pressure may be applied alter addition of the last increment of n-pentane. Otherwise, gas pressure should be applied when n-pentane begins to elute from the column and should be adjusted to give a flow rate of approximately 1 mL/min. 8.4.4 When the n-pentane level reaches the top of the bauxite bed, add 80 m L of diethyl ether (Warning-Extremely flammable.). Connect the pressuring gas to the top of the column and adjust the pressure to maintain an elution rate of l to 2 mL/min. 381

8.4.5 Collect 50 m L of n-pentane eluate in the graduate. Rinse the tip of the column with 1 to 2 m L of n-pentane, adding this to the 50 m L in the graduate (Note 5). Label the 50-mL graduate as n-pentane eluate. NOTE 5--The n-pentane will have reached the adsorbent bed before the required volume of eluate has been collected in the 50-mL receiver. Continue collection in this receiver after the addition of ether until the proper volume has been collected before changing to the 100-mL graduate. 8.4.6 When the ether level reaches the top of the bauxite bed, release the gas pressure and add 100 m L of chloroform (Warning--Toxic. May be fatal if swallowed.) to the top of the column. Reconnect the gas pressuring system and continue the elution. When 80 m L of eluate have been collected in the graduate, rinse the column tip with 1 m L of ether and add the rinse to the 100-mL graduate. Change the receiver to a 250-mL graduate. Label the 100-mL graduate as ether-eluted fraction. 8.4.7 When the chloroform level reaches the top of the bauxite bed, release the gas pressure and add 75 m L of ethyl alcohol (Warning--Flammable liquid.). Reconnect the gas pressuring system and continue the elution until the alcohol level reaches the top of the bauxite bed. Release the gas pressure. Rinse the column tip with 1 m L of chloroform adding this to the graduate. Label the 250-mL graduate as chloroform-alcohol-eluted fraction. 8.4.8 Weigh a 100-mL inverted-tim beaker to the nearest 1 mg. Quantitatively transfer the n-pentane eluate to this beaker and allow the n-pentane to evaporate at room temperature. Cyclohexane, if used as the elution solvent, is evaporated on a steam bath. Evaporation is accelerated in both cases by directing a controlled stream of dry nitrogen downward onto the surface of the liquid. 8.4.9 When all the solvent appears to be evaporated, stop the nitrogen flow, allow the beaker to come to room temperature, and dry the outside of the beaker to remove any condensed moisture. Reweigh the beaker to the nearest 1

mg. NOTI~ 6--Complete solvent evaporation is indicated by a tendency of the oil to creep up the side of the beaker. 8.4. l0 Repeat the evaporation step for 5-rain periods until the weight loss between successive evaporations is less than 20 mg. Heat from a steam bath is generally required during the final evaporation steps to remove completely the elution solvent. The weight of the residue in the beaker is the quantity of the nonaromatics fraction. 8.4.11 Weigh a 250-mL inverted-rim beaker to the nearest 1 mg. Quantitatively transfer the chloroform-alcohol-eluted fraction to this beaker and evaporate on a steam bath with a controlled stream of dry nitrogen directed downward onto the surface of the liquid. When the solvent is evaporated, remove the beaker from the steam bath, cool to room temperature, and add quantitatively the ether-eluted fraction. Evaporate the ether at room temperature as described in 8.4.8, 8.4.9, and 8.4.10. Determine the weight of the residue (aromatics fraction) to the nearest 1 rag. 8.4.12 The weight of the aromatics plus the nonaromatics fraction recovered must equal at least 95 % of the sample charged. If 95 % recovery is not obtained, repeat the test. Recoveries greater than 100 % indicates incomplete removal

~

D 2549

of solvent or the condensation of moisture in the beakers. 8.4.13 Transfer the aromatics and nonaromatics fractions into suitable size vials for storage pending further analysis. 8.5 If 10 g of sample are to be analyzed, continue as in 8.5.1. 8.5.1 Warm the sample with intermittent mixing or shaking until it is completely fluid. Transfer a representative sample (approximately 8 to I0 g) to a 50-mL weighing bottle or flask. Determine the weight of the sample to the nearest 1 mg by weighing the flask before and after sample transfer. Add 20 m L of n-pentane to the flask and dissolve the sample. If the sample does not dissolve completely in cold n-pentane warm it in warm water or over a steam bath. If the sample does not dissolve in warm n-pentane, take a fresh sample and substitute cyclohexane for n-pentane. 8.5.2 Add 45 m L ofn-pentane to the top of the prepacked large column to prewet the adsorbent. When the n-pentane level reaches the top of the bauxite bed, transfer the sample solution from the weighing flask to the top of the column. Rinse the flask with three successive 3-mL washes of n-pentane. Add each wash to the top of the column. Then rinse the walls of the column bulb with two 3-mL portions of n-pentane, allowing the level of each portion to reach the top of the bauxite bed before adding the next portion. Finally add 70 m L of n-pentane to the column bulb. 8.5.3 Place a 200-mL graduate beneath the column to collect the eluate. The elution rate should be approximately 3 mL/min. NOTE 7--Air or nitrogen pressure may be applied to the top of the column as necessary to accomplish and maintain a satisfactory elution rate. Three to five pounds of pressure generally is sufficient. If the correct pressure setting is known from previous runs, gas pressure can be applied after addition of the last increment of n-pentane. Otherwise, gas pressure should be applied when n-pentane begins to elute from the column and should be adjusted to give a flow rate of approximately 3 mL/min. 8.5.4 When the n-pentane level reaches the top of the bauxite bed, add 100 m L of diethyl ether. Connect the pressuring gas to the top of the column and adjust the pressure to maintain an elution rate of 3 to 5 mL/min. 8.5.5 Collect 130 m L of eluate in the graduate. Rinse the tip of the column with l to 2 m L of n-pentane, adding this to the 130 m L in the graduate. Change the receiver to a 100-mL graduate (Note 8). Label the 200-mL graduate as n-pentane eluate. NOTE 8--The n-pentane will have reached the absorbent bed before the required volume ofeluate has been collected in the 200-mL receiver. Continue collection in this receiver after the addition of ether until the proper volume has been collected before changing to the 100-mL graduate.

8.5.7 When the chloroform level reaches the top of the bauxite bed, release the gas pressure and add 175 mL of ethyl alcohol. Reconnect the gas pressuring systems and continue the elution until the alcohol level reaches the top of the bauxite bed. Release the gas pressure. Rinse the column tip with 1 m L of chloroform adding this to the graduate. Label the 500-mL graduate as chloroform-alcohol-eluted fraction. 8.5.8 Weigh a 250-mL inverted rim beaker to the nearest 1 mg. Quantitatively transfer the n-pentane eluate to this beaker and evaporate the solvent on a steam bath. Evaporation can be accelerated by directing a controlled stream of dry nitrogen downward onto the surface of the liquid. Complete the workup of the nonaromatics fraction as described in 8.4.9 and 8.4.10. 8.5.9 Weigh a 600-mL inverted rim beaker to the nearest l m g (Note 9). Complete the workup of the aromatics fraction as described in 8.4. l l, 8.4.12, and 8.4.13. NOTE 9--The 600-mL inverted-rim beakers from some sources can exceed the capacity of the standard analytical balance, in which case a 250-mL inverted rim beaker can be used, and the chloroform-alcoholeluted fraction evaporated in increments. 9. Calculation 9.1 Calculate the percentage of the aromatics fraction and the nonaromatics fraction as follows: Aromatics fraction, w~ % -- [A/(A + B)] x 100 (l) Nonaromatics fraction, wt % = [B/(A + B)] x I00 (2) where: A = weight of aromatics fraction recovered, and B = weight of nonaromatics fraction recovered. 10. Precision and Bias 10.1 The following criteria should be used for judging the acceptability of results (95 % probability): 10.1.1 R e p e a t a b i l i t y D T h e difference between successive test results, obtained by the same operator with the same apparatus under constant operating conditions on identical test material would, in the long run, and in the normal arid correct operation of the test method, exceed the following values only in one case in twenty: 0.4 weight % for 10 g of sample; and 1.4 weight % for 2 g of sample. 10.1.2 Reproducibility--The difference between two, single and independent results, obtained by different operators working in different laboratories on identical test material would, in the long run, and in the normal and correct operation of the test method, exceed the following values only in one case in twenty: 1.6 weight % for l0 g of sample; and 1.5 weight % for 2 g of sample. NOTE 10--The procedure for analyzing 2 g of sample gives recoveries of aromatics fractions that are on average 0.35 weight % lower than the procedure for analyzing l0 g of sample.

8.5.6 When the ether level reaches the top of the bauxite bed, release the gas pressure and add 100 m L of chloroform to the top of the column. Reconnect the gas pressuring system and continue with the elution. When 100 m L of eluate have been collected in the graduate, rinse the column tip with 1 m L of ether and then change the receiver to a 500-mL graduate. Label the 100-mL graduate as ether-eluted fraction.

I0.2 B i a s D B i a s cannot be determined because there are no reference materials suitable for determining the bias in this test method. NOTE l l--The precision of the procedure in Annex A l has not been determined.

382

4t~ D 2549

ANNEXES

(Mandatory Information) AI. L O W E R BOILING S A M P L E PROCEDURE A1.5.12 Separate weighing bottle containing the concentrated pentane solution from the flask and weigh it after it has cooled to room temperature. A1.5.13 Gently swirl weighing bottle on the hot steam bath surface while directing a gentle stream of nitrogen to the bottle (Note AI.1). After 3 min, cool to room temperature and weigh. NOTE A I.I--Use nitrogen rate of approximately 100 mL/min. Do not direct nitrogen flow on liquid, but rather along inside of weighing bottle. A1.5.14 Repeat step A1.5.13 at 2-min intervals until weight loss between successive evaporations is less than 50 mg. The weight of the residue in the weighing bottle is the nonaromatic fraction. A1.5.15 Quantitatively transfer the chloroform-alcoholeluted fraction from A1.5.10 to a 600-mL beaker and evaporate off the solvent on a steam bath using a stream of nitrogen to facilitate the evaporation rate. Allow to cool to room temperature. A1.5.16 Weigh a 30-mL conical weighing bottle and attach to Kuderna-Danish apparatus as .described in A 1.5.11. Transfer the ether-eluted fraction A1.5.9 into the beaker containing the residue from A1.5.15. Quantitatively transfer this mixture into the flask and evaporate on the steam bath as described in A1.5.11. A1.5.17 Complete the workup of the aromatic fraction as described in A1.5.12, A1.5.13, and A1.5.14. AI.5.18 Same as 8.4.12. A1.5.19 Same as 8.4.13.

AI.1 Scope A1.1.1 This procedure covers the separation and determination of representative aromatics and nonaromatics fractions from hydrocarbon mixtures whose 5 % boiling point is below 232"C (450"F), but above 178"C (350"F). AI.2 Summary of Method A I.2.1 A Kuderna-Danish apparatus is used to evaporate solvents from the aromatic and nonaromatic fractions.

AI.3 Significance and Use A1.3.1 This procedure extends the range of this test method to separate the samples whose boiling range is specified in Test Methods D 2425, D 2786, and D 3239, all of which refer to this method to provide fractions for analyses. A1.4 Apparatus A 1.4.1 Kuderna-Danish Evaporator." A1.4.1.1 250-mL Flask, with top female standard taper 24/40 and bottom male standard taper 24/12 with glass hooks for retaining springs. A1.4.1.2 Macro Snyder Distillation Column, 3 ball, with male standard taper 24/40. AI.4.1.3 Conical Weighing Bottles, with female standard taper 24/12, 30-mL capacity with glass hooks for retaining springs. AI.5 Procedure A1.5.1 The 10-g chromatographic column is used. Clean column with chromic-sulfuric acid, distilled or demineralized water, acetone, and dry air or nitrogen. AI.5.2 Same as 8.2. AI.5.3 Same as 8.3. A1.5.4 Same as 8.5.1 AI.5.5 Same as 8.5.2. A1.5.6 Same as 8.5.3. A1.5.7 Same as 8.5.4. A1.5.8 Same as 8.5.5. A1.5.9 Same as 8.5.6. A1.5.10 Same as 8.5.7. A1.5.11 Weigh a 30-mL conical weighing bottle, to which a boiling chip is added, to the nearest 1 mg. Attach the weighing bottle to the 250-mL flask with the retaining springs. Quantitatively transfer the n-pentane eluate to the flask. Attach the Snyder distillation column to the flask and evaporate on a steam bath. Evaporation of most of the n-pentane is complete when balls in the Snyder distillation column stop moving.

AI.6 Calculation AI.6.1 Same as 9.1. A1.7 Results AI.7.1 Two samples representing aromatic and nonaromatic concentrates from a middle distillate with an initial boiling point 149"C (300*F) were subjected to the evaporation procedure. Interlaboratory testing on the preceding samples was done by five laboratories, in duplicate, at two different times. Recoveries of 97 to 102 % with less than 3 % solvent remaining were obtained in the last study. A1.8 Precision and Bias A1.8.1 There are no interlaboratory test data to establish a statistical statement of precision for the procedure in Annex A1 of Test Method D 2549. A1.8.2 There are no interlaboratory test data to establish a statistical statement of bias for the procedure in Annex A I of Test method D 2549.

383

(@) D 2549 The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend. If you fee/that your comments have not received a fair heanng you should make your views known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103.

384

~T~

Designation: D 2593 - 93

@

Designation: 194/74

An American National Standard

Standard Test Method for Butadiene Purity and Hydrocarbon Impurities by Gas Chromatography 1 This standard is issued under the fixed designation D 2593; the number immediately following the desisnation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (~) indicates an editorial change since the last revision or reapproval. This test method was adopted as a joint ASTM-IP Standard in 1972.

1. Scope 1.1 This test method provides for the determination of butadiene-l,3 purity and impurities such as propane, propylene, isobutane, n-butane, butene-l, isobutylene, propadiene, trans-butene-2, cis-butene-2, butadiene-l,2, pentadiene-l,4, and, methyl, dimethyl, ethyl, and vinyl acetylene in polymerization grade butadiene by gas chromatography. Impurities including butadiene dimer, carbonyls, inhibitor, and residue are measured by appropriate ASTM procedures and the results used to normalize the component distribution obtained by chromatography. NOTEl--Otherimpurities present in commercialbutadiene must be calibrated and analyzed. Other impurities were not tested in the cooperative work on this test method. Nor~ 2--This test method can be used to cheek for pentadiene-l,4 and other Css instead of Test Method D 1088. 1.2 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements, see Notes 4, 5, and 9.

peak areas or peak heights and the relative concentration determined by relating individual peak response to total peak response. Impurities including butadiene dimer, carbonyls, inhibitor, and residue are measured by appropriate ASTM procedures and the results used to normalize the distribution obtained by gas chromatography.

4. Significanceand Use 4.1 The trace hydrocarbon compounds listed can have an effect in the commercial use of butadiene. This test method is suitable for use in process quality control and in setting specifications. 5. Apparatus 5.1 Chromatograph--Any chromatograph having either a thermal-conductivity or flame ionization detector can be used provided the system has sufficient sensitivity and stability to obtain a recorder deflection of at least 2 mm at signal-to-noise ratio of at least 5:1 for 0.01 weight % of impurity. 5.2 Column--Any column can be used that is capable of resolving the components listed in 1.1 with the exception of butene-1 and isobutylene, which can be eluted together. The components should be resolved into distinct peaks such that the ratio A / B will not be less than 0.5 where A is the depth of the valley on either side of peak B and B is the height above the baseline of the smaller of any two adjacent peaks. In the case where the small combonent peak is adjacent to a large one, it can be necessary to construct a baseline of the small peak tangent to the curve as shown in Fig. 1. 5.2.1 A description of columns that meet the requirements of this test method is tabulated in the Appendix. Persons using other column materials must establish that the column gives results that meet the precision requirements of Section 11. 5.3 Sample Inlet System--Means shall be provided for introducing a measured quantity of representative sample into the column. Pressure-sampling devices can be used to inject a small amount of liquid directly into the carrier gas. Introduction can also be accomplished by use of a gas valve to charge the vaporized liquid. 5.4 Recorder--A recording potentiometer with a full-scale deflection of 10 mV or less is suitable for obtaining the chromatographic data. Full-scale response time should be 2 s or less, and with sufficient sensitivity to meet the requirements of 5.1.

2. ReferencedDocuments 2.1 A S T M Standards: D 1088 Test Method for Boiling Point Range of Polymerization-Grade Butadiene 2 E 260 Practice for Packed Column Gas Chromatography 3

3. Summaryof Test Method 3. I A representative sample is introduced into a gas-liquid partition column. The butadiene and other components are separated as they are transported through the column by an inert cartier gas. Their presence in the effluent is measured by a detector and recorded as a chromatogram. The chromatogram of the sample is interpreted by applying component attenuation and detector response factors to the i This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.D on Hydrocarbons for Chemical and Special Uses. Current edition approved Feb. 15, 1993. Published April 1993. Originally published as D 2593 - 67. Last previous edition D 2593 - 86. 2 Discontinued; See 1984 Annual Book of ASTM Standards, Vol 05.01. 3 Annual Book of ASTM Standards, Vol 14.01.

385

i1~) D 2 5 9 3

NOTE 3--Other methods of recording detector output such as computer-teletype systemscan be used instead of a recorder, provided precision requirements of Section I l are met. 6. Reagents and Materials 6.1 CarrierGas--A carrier gas appropriate to the type of detector used should be employed. Helium or hydrogen may be used with thermal conductivity detectors. Nitrogen, helium, or argon may be used with ionization detectors. The minimum purity of any carder should be 99.95 tool %. NOTE 4: Warning--Compressedgas. Hazardous pressure. NOT~ 5: Warning:--Hydrogen flammablegas. Hazardous pressure. 6.1.1 If hydrogen is used, special safety precautions must be taken to ensure that the system is free from leaks and that the effluent is properly vented. 6.2 Column Materials: 6.2.1 Liquid Phase--The materials that have been used successfully in cooperative work as liquid phases are listed in the Appendix (Table X 1.1). 6.2.2 Solid Support--The support for use in the packed column is usually crushed firebrick or diatomaceous earth. Sieve size will depend on the diameter of the column used and liquid-phase loading, and should be such as would give optimum resolution and analysis time. Optimum size ranges cannot be predicted on purely theoretical grounds. For some systems it has been found that a ratio of average particle diameter to column inside diameter of 1:25 will result in minimum retention time and minimum band widths. 6.2.3 Tubing Material--Copper, stainless steel, Monel, aluminum, and various plastic materials have been found to be satisfactory for column tubing. The material must be nonreactive with respect to substrate, sample, and carder gas and of uniform internal diameter. 6.3 Hydrocarbons for Calibration and Identification-Hydrocarbon standards for all components present are needed for identification by retention time and for calibration for quantitative measurements. NOTE 6--Mixtures of hydrocarbons can be used provided there is no uncertainty as to the identity or concentration of the compounds involved. 7. Preparation of Apparatus

7.1 Column Preparation--The technique used to prepare

the column is not critical as long as the finished column produces the desired separation. Preparation of the packing is not difficult once the support, partitioning liquid, and loading level have been determined. The following general directions have been found to produce columns of acceptable characteristics. 7.1.1 Weigh out the desired quantity of support, usually twice that required to fill the column. 7.1.2 Calculate and weigh out the required quantity of partitioning agent. Dissolve the partitioning agent in a volume of chemically inert, low-boiling solvent equal to approximately twice the volume of support. 7.1.3 Gradually add the support material to the solution with gentle stirring. 7.1.4 Slowly evaporate the solvent while gently agitating the mixture until the packing is nearly dry and no free liquid is apparent. 7.1.4.1 Some stationary phases such as benzyl cyanide silver nitrate are susceptible to oxidation and must be protected from excessive exposure to air during the evaporation and drying steps. 7.1.5 Spread the packing in thin layers on a nonabsorbent surface and air- or oven-dry as required to remove all traces of solvent. 7.1.6 Resieve the packing to remove fines and agglomerates produced in the impregnation step. 7.1.7 Fill the column tubing with packing by plugging one end with glass wool and pouring the packing into the other end through a small funnel. Vibrate the tubing continuously over its entire length while filling. When the packing ceases to flow, tap the column gently on the floor or bench-top while vibrating is continued. Add packing as necessary until no further settling occurs during a 2-rain period. Remove a small amount of packing from the open end, plug with glass wool, and shape the column to fit the chromatograph. 7.2 Chromatograph--Mount the column in the chromatograph and establish the operating conditions required to give the desired separation (Appendix X l). Allow sufficient time for the instrument to reach equilibrium as indicated by a stable base line. Control the oven temperature so that it is constant to within 0.5"C without thermostat cycling which causes an uneven base line. Set the carder-gas flow rate, measured with a soap film meter, so that it is constant to within 1 mL/min of the selected value. 8. Calibration

8.1 Identification--Select the conditions of column temperature and carrier gas flow that will give the necessary separation. Determine the retention time for each compound by injecting small amounts of the compound either separately or in mixtures. Recommended sample sizes for retention data are 1 ~tL for liquids and 1 cm 3 or less for gases. 8.2 Standardization--The area under the peak of the chromatogram is considered a quantitative measure of the amount of the corresponding compound. The relative area is proportional to the concentration if the detector responses of the sample components are equal. The recommended procedure for quantitative calibration is as follows: with all equipment at equilibrium at operating conditions, inject

FIG. 1 Illustration of A/B Ratio for Small-Component Peak

386

i ~ D 2593 constant volume samples of high-purity components. Each compound should be injected at least three times. The areas of the corresponding peaks should agree within 1%. When a recorder is used, adjust the attenuation in all cases to keep the peak on-scale and with a height of at least 50 % of full scale. Measure the area of the peaks by any reliable method (Note 10). To obtain component weight % response data from the area response of the volume injections, it is necessary to consider the density and purity of the compounds used for calibration. The average volume area response of each component is divided by the density multiplied by the weight percent purity of the component as follows: Weight percent response of component (1) average component peak area density × weight percent purity of component Component weight percent detector correction factors are then obtained by selecting a reference component such as butadiene, and dividing the individual component weight responses into the reference weight response. 8.2.1 Factors derived on a thermal-conductivity detector using helium-carrier gas are as follows: Component Butadiene- 1,3 Propane Propylene Isobutane n.Butane Butene- I Isobutylene

trans.Butene-2 cis-Butene-2 Propadiene Methyl acetylene

Mol wt

Thermal Response

Weight Factor

Weight Factor, Butadiene- 1,3 = 1.00

54 44 42 58 58 56 56 56 56 40 40

80 65 63 82 85 81 82 85 87 53 58

0.68 0.68 0.67 0.71 0.68 0.69 0.68 0.66 0.64 0.75 0.69

1.00 1.00 0.98 1.04 1.00 1.01 1.00 0.97 0.94 1.10 1.01

NOTE 7--Response based on data represented by Messner, A. E., Rosie, D. M., and Argabright, P. A., Analytical Chemistry, Vol 31, 1959, pp. 230-233, and Dietz, W. A., Journal of Gas Chromatography, Vol 5, No. 2, 1967, pp. 68-71.

function of the carbon content, giving essentially equal relative response to hydrocarbons containing the same number of carbon atoms.

8.2.3 Because detector or amplifier output need not be linear with component concentration, this must be checked by injecting constant volumes of pure butadiene at a series of decreasing pressures from ambient down to 20 mm Hg (ton') or by using synthetic standards with vapor sample valves at ambient or at decreasing pressures or by using synthetic standards with liquid sample valves. If on plotting the results the response is linear, then the calibration procedure given above is satisfactory. If not, the relative responses of the minor components must be determined in the linear response region. 9. Procedure

9.1 Attach the sample cylinder to the instrument-sampiing valve so that the sample is obtained from the liquid phase. If introduction is through a liquid valve the sample cylinders should be pressured with a suitable gas, such as helium, to a pressure sufficient to ensure that sample flashing does not occur in the line to the sampling valve or in the valve itself.If a vapor valve is used, care must be taken to completely vaporize a small liquid sample, allowing the vapor to flow through the sample loop at a flow rate of 5 to I0 mL/min until at leastten times the volume of the sample loop has been flushed through. If a vacuum-sampling system is used with a vapor valve, the sample loop should be filled and evacuated at least twice before introduction of sample. 9.2 Charge sufficient sample to ensure a m i n i m u m of 10 % recorder deflection for 0.1% concentration of impurity at the most sensitiveoperating settingof the instrument (for trace impurities, such as acetylenes, greater sensitivity is needed). 9.3 Using the same conditions as were used for calibration, record the peaks of all compounds at attenuation or sensitivitysettingsthat allow m a x i m u m peak heights. NOTE 9: Warning--Butadiene flammable gas under pressure.

10. Calculation

8.2.1.1 Although not determined with standards, weight factors of 1.00 (compared to butadiene 1,3 as 1.00) were used for pcntadiene-l,4 butadiene-l,2, dimethyl acetylene, ethyl and vinyl acetylene in this study to obtain the precision listed in Section 11. It is permissible to use the above established response factors instead of calibration when using thermalconductivity detectors with helium-carrier gas. With other detectors or carrier gas, or both, it is necessary to calibrate (Note 7). 8.2.2 Measurements can be made using peak heights as criteria for calculations instead of peak areas. If peak heights are used, care must be taken so that chromatographoperating parameters such as column temperature and carrier-gas flow rate are kept at the same conditions as when the unit was calibrated. The chromatograph can be calibrated using known blends or by establishing relativeresponse data using peak heights in the same manner as listed above.

10.1 Measure the area or heights of all peaks (Note 10) and multiply by the appropriate attenuation factor to express the peak area or heights on a common sensitivity basis. Apply the appropriate calibration factors to the peak areas or heights to correct for the differences in response to the components. Make area calculations by relating the individual component corrected area to the total corrected area of all peaks. If peak heights arc used, multiply the peak heights, calibration factors,and component attenuations for each component and normalize the resultingproducts to give percentages. Make corrections to account for the direct, carbonyl, inhibitor residue (and acetylene if not determined chromatographically) concentration as determined by separate A S T M procedures. Calculations arc as follows: Corrected peak response Sum of correctedpeak responses (2) I00 - sum of dimer, carbonyl,inhibitorand residual] x impurities(and acetyleneifnot determined chromatographically) NOTE 10raThe areacan be determinedby any method thatmeets the precision requirements of Section II. Methods found to be

J

NOTE S--Use of a hydrogen-flamedetector gives essentially equal relative responseto hydrocarbons. On a weight basis, the sensitivityof the flame detector for hydrocarbons is essentially independent of the hydrocarbons structure. On a molar basis, the sensitivityappears to be a 387

t{~ D 2593 11.1.2 Reproducibility---The difference between two single and independent results obtained by different operators working in different laboratories on identical test material would, in the long run, and in the normal and correct operation of the test method, exceed the following values only in one case in twenty:

acceptable include planimetering, integration (electronic or mechanical or computer processing), and triangulation (multiplying the peak height by the width at the half height).

11. Precision and Bias 4 11.1 The precision of the test method as determined by statistical examination of interlaboratory results is as follows: 11.1.1 Repeatability---The difference between successive test results, obtained by the same operator with the same apparatus under constant operating conditions on identical test material would, in the long run, and in the normal and correct operation of the test method, exceed the following values only in one case in twenty: Component Butadiene-1,3 Propane Propadiene Propylene

lsobutane n-Butane Butene- I and isobutylene trans-Butene.2 cis-Butene.2

Butadiene- 1,2 Pentadiene- 1,4 Dimethyl acetylene Total methyl, ethyl + vinyl acetylene

Concentration, weight percent

Repeatability, weight percent

99.0 0,02 0. I I O.I 1 0.07 0.06 0.23 0.09 O. ! 3

0.079 0.005 0.013 0.017 0.010 0.008 0.01 I 0.008 0.016

0.08

0.016

0. i 2 0.05 0.034

0.0 ! 3 0.0l I 0.004

Concentration, Reproducibility,

Component Butadiene-i,3 Propane Propadiene Propylene lsobutane n-Butane Butene-I and isobutylene trans-Butene-2 cis-Butene-2

Butadiene- 1,2 Pentadiene- 1,4 Dimethyl acetylene Total methyl, ethyl + vinyl acetylene

weight percent

weight percent

99.0 0.02 0. I i 0. I I 0.07 0.06 0.23 0.09 0.13 0.08 0. ! 2 0.05 0.034

0.28 0.013 0.087 0.092 0.027 0.025 0.240 0.036 0.046 0.052 0.070 0.054 0.014

I 1.2 Bias--Since there is no acceptable reference material suitable for determining the bias for the procedure in this test method, bias has not been determined. 12. Keywords 12.1 butadiene; gas chromatography

4 Round-robin data for this method may be obtained from ASTM Headquartots. Request RR: D02-1004.

APPENDIX (Nonmandatory Information) Xl. COLUMNS AND CONDITIONS X I.I The columns and conditions given in Table X l.1 have been used successfully for this analysis in cooperative work. Columns and conditions other than those listed may

be used provided they are capable of meeting the resolution and precision requirements of the method.

TABLE XI.1 Appears on Followipg Pages

388

q~ D 2593

TABLE X1.1 Case I Column: Substrate Weight, Support Mesh size Treatment Length, m (ft) Diameter, mm (in.) Temperature, °C Carrier gas Flow rate, cm3/mtn Detector, type Voltage or mA Recorder, range, mV Speed, mm (in.)/min Sample Valve Size Split ratio Peak measurement Area or height Method Retention time, min Propane Propylene Isobutane n-Butane Butene*l Isobutylene Propadlene trans.Butene-2

bis-2-methoxy-ethoxy ethyl ether diisodecyl phthalateA 25 Chromosorb pe 60 to 80 no treatment 6.1 (20) 4.8 (S/la) 26 helium 60 thermal conductivity 7.5V 0to5 25.4 (1)

Chromatographic Conditions Case II

0to1

0to1 12.7 (l/z)

vapor 1 cms @ 15 in. vaccuum none

vapor 1 cma none

liquid 1.54 HL none

liquid 0.47 HL none

area triangulation

height

area triangulation

area planimeter

3.6 4.3 5.7 6.8 8.8 8.8 7.9 11.9 13.7 15.6 25.0 14.8 32.4 49.1 53.7 30.7

4.7 5.1 5.1 5.7 8.5 8.5 7.2 7.2 7.7 9.3 12.1

cia-Butene-2

11.7

Butadlene-1,3 Butadlene-1,2 Methyl acetylene Ethyl acetylene Vinyl acetylene Dimethyl acetylene Pentadiene-1,4

13.4 21.3 12.7 27.7 42.0 45.7 26.0

15 Chromosorb P 30 to 60 no treatment 6.1 (20) 4.8 pAe) 27 helium 60 thermal conductivity

3.4 3.7 4.6 5.5 6.2 6.2 5.1 7.2 7.8 11.5 6.2 12.3 14.8 22.0 18.4

389

bis-2-methoxy-ethoxy ethyl ether A dlisodecyl phthalate 25 Chromosorb P 60 to 80 no treatment 6.1 (20) 4.8 pAe) 26 helium 60 hydrogen flame

Case IV (1) sulfolanec (2) didecyl phthalate 30 Chromosorb P 60 to 80 no treatment (1) 6.4 (21) (2) 1.07 (3.5) 3.2 (Ve) 25 helium 12.5 thermal conductivity 8V 0to1 25,4 (1)

3.3 4.0 5.0 6.8 8.4 8.4 7.8 10.2

di-n-butyl maleate

Case 111

17.3 24.6 29.2 13.6

~

D 2593

TABLE X1.1

Continued CaseV

Column: Substrata Weight percent Support Mesh size Treatment Langth, m (ft) Diameter, mm (in.) Temperature, "C Carder gea Flow rate, crn~/min Detector, type Voltege or mA Recorder, range, mV Speed, mm (In.)/mln San~e Valve Size Split ratio Peak measurement Area or height Method Retention time, min Propane P ~ laobutane n-Butane Butane-1 laobuty~ne Propedlane trans-Butene-2 cle-Butane-2 Butadlane-1,3 Butadlane-1,2 Methyl acetylene Ethyl acetylene Vin~ acetykm Dlmethyl acetylene Pantadlane-1,4

(1) bis-2-rnethoxyemyl adipete o (2) 1,3-trla(2.cyanoethoxy)-propene 15 Chromosorb pm 60 to80 no treatment (I) 7.3 (24) (2) 1.8 (6) 6.4 (~) 65 helium 140 thermal conductivity 2O0 mA 0to1 12.7 (1/=)

I.ICON LB-550X =

B,B'-oxydiproplonitrila

20 Chromosorb P 60 to 80 no treatment 7.8 (29) 8.4 (~) 68 helium 110 thern~ condu~v|ty 2OO mA 0to1 12.7 (1/=)

20 Chromosorb P 60 to 80 no treatment 7.8 (25) 8.4 (~A) 25 helium 115 flame 3O0 mA 0to1 12.7 (½)

liquid 5 pL none

liquid 5 pL none

,qu~ 5 pL none

area disk integrator

area disk integrator

8re8 triangulation

5.3 6.1 7.5 7.7 9.3 9.5 9.5 10.5 11.5 13.0 17.6 11.8 21.3 27.7 33.1 19.8

5.2 5.5 6.6 8.0 8.4 8.4 7.4 9.3 9.6 9.6 13.8 8.0 13.4 18.5 21.2 15.8

4.5 5.2 4.9 5.2 6.7 6.9 8.2 7.4 8.2 10.9 13.5 14.1 20.8 28.3 35.8 14.1

390

(IN D 2593

T A B L E X1.1

Continued

Case Vl Column: Substrate Weight percent Support Mesh size Treatment Length, m (ft) Diameter, mm (in.) Temperature, °C Carder gas Flow rate, orn3/min Detector, type Voltage or mA Recorder, range, mV Speed, mm (in.)/min Sample Valve Size Split ratio Peak measurement Area or height Method Retention time, min Propane Propylene Isobutane n-Butane Butane-1 Isobutylane Propadiene trans-Butene-2 tie-Butane-2 Butadiane-1,3 Butadiane-1,2 Methyl acetylene Ethyl acetylene Vinyl acetylene Dimethyl acetylene Pentadlene-1,4

Case Vll

tributyl phosphate

B,B'-oxydiproplonitrile

15 Chromosorb pa 30 to 60 no treatment 18.3 (60) 3.2 (Y=) 25 helium 60 flame

13.7 (45) 4.8 p/le)

15 Chromosorb P 40 to 60

(I) squalane F (2) dimethyl sulfolane (1) 15 (2) 20 C-22 firebrick 60 to 80

(1) 20 (2) 20 C-22 firebrick 60 to 80

no treatment

no treatment

no treatment

6.1 (20) 3.2 (1A) 25 helium 45 flame

(1) 1.5 (5) (2) 4.6 (15) 4.8 p/l= ) 25 helium 36 thermal conductivity 300 mA 0to1 12.7 (Y=)

Case Vlll propylane carbonate 30 firebrick BS 60 to 85 (251 to 178 p.m) acid and water-washed and dded 4.9 (16) 4.8 (=/le) 30 ± 0.5 helium or hydrogen 55 to 65 thermal conductivity

0to1 25.4 (1)

0to1 25.4 (1)

(1) 1.7 (5%) (2) 7.0 (23) 6.4 (¼) 25 helium 84 thermal conductivity 310 mA 0to1 25.4 (1)

vapor 1.5 ore3 none

vapor 3 cm a none

liquid 3 I~L none

vapor vapor 8 cma @ 2 in. vacuum up to 2 mL none none

area triangulation

area triangulation

area triangulation

area triangulation

thermal conductivity 125 mA

8.9 9.7 13.9 18.6 20.5 20.5 16.0 24.8 14.8 30.0 43.5 22.3

2.24 2.64 2.64 3.04 3.92 4.16

7.2 7.9 9.1 12.6

4.48 4.96 6.24 8.40

28.4 14.8

56.6

peak height x retention time

3.8 4.2 4.6 5.7 6.2 6.2

9.0 17.0 24.0

7.0 9.5 12.8

()'to 10 12.5 p'/e,)

13.44 17.92 18.96 10.08

A Mixed bed column containing 18.5 parts of 25 weight % diisodecyl phthalate and 81.5 parts 25 weight ~ bis-2-methoxy-ethoxy ethyl ether. a *Chromosorb" is a trademark of Johns.Manville Products Corp. c Columns in sedas--8.4 m (21 ft) of sulfolane followed by 1.1 m (3.5 ft) of didecyl phthelate. o Columns in series--7.3 m (24 ft) of adipata followed by 1.8 m (6 ft) of tris-cyanoethoxy propane. *UCON" is a trademark of Union Carbide Corp. F Columns in sedas--1.7 m (5% ft) of squalane followed by 7.0 m (23 ft) of dimethyl sulfolane. o This column and chromatographic technique is described more fully in the Institute of Petroleum's Test Method IP 194, "Analysis of Butadiene-1,3 Polymedzation Grade."

The American Society for Tasting end Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard ere expressly advised that determination of the validity of any such patent rights, and the risk of infr/ngemant of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and ff not revised, either raspproved or withdrawn. Your comments ere invited either for revision of thia atandard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103.

391

Designation:D 2597 - 94

An AmericanNationalStandard

Standard Test Method for Analysis of Demethanized Hydrocarbon Liquid Mixtures Containing Nitrogen and Carbon Dioxide by Gas Chromatography I This standard is issued under the fixed designation D 2597; the number immediately following the designation indicates the year of original adoption or, in the ease of revision, the year of last revision. A number in parentheses indicates the year of last re.approval. A superscript epsilon (~) indicates an editorial change since the last revision or reapproval.

1. Scope 1.1 This test method covers the analysis of demethanized liquid hydrocarbon streams containing nitrogen/air and carbon dioxide, and purity products such as an ethane/ propane mix that fall within the compositional ranges listed in Table 1. This test method is limited to mixtures containing less than 5 tool % of heptanes and heavier fractions. 1.2 The heptanes and heavier fraction, when present in the sample, is analyzed by either (1) reverse flow of carrier gas after n-hexane and peak grouping or (2) precut column to elute heptanes and heavier first as a single peak. For purity mixes without heptanes and heavier no reverse of carrier flow is required. NOTE 1: Caution--Inthe case of unknownsampleswith a relatively large C6 plus or C7 plus fractionand wherepreciseresultsare important, it is desirable to determine the molecular weight (or other pertinent physical properties) of these fractions.Since this test method makes no provision for determining physical properties, the physical properties needed can be determinedby an extendedanalysisor agreed to by the contracting parties. 1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements see Annex A3. 2. Referenced Documents

2. I A S T M Standard." D 3700 Practice for Containing Hydrocarbon Fluid Sampies Using a Floating Piston Cylinder2 2.2 Other Standard." GPA Standard 2177 Analysis of Demethanized Hydrocarbon Liquid Mixtures Containing Nitrogen and Carbon Dioxide by Gas Chromatography3 3. Summary of Test Method 3.1 Components to be determined in a demethanized i This test method is under the jurisdiction of Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.H on Liquefied Petroleum Gas. Current edition approved July 15, 1994. Published September 1994. Originally published as D 2597 - 67T. Last previous edition D 2597 - 88. 2 Annual Book of ASTM Standards, Vol 05.02. 3 Available from Gas Processors Assn., 6526 E. 60th St., Tulsa, OK 74145.

392

TABLE 1

Componentsand Compositional Ranges Allowed Components

Nitrogen Carbon Dioxide Methane

Ethane Propane Isobutane n-Butane and 2,2-Dimethylpropane Isopentane n-Pantane 2,2-Dlmothylbutane 2,3-Dlmethylbutane and 2.Methylpentane 3-Methylpentane and Cyclopentane n-Hexane Heptanes and Heavier

ConcentrationRange. M(~ 0.01-5.0 0.01-5.0 0.01-5.0 0.01-95.0 0.01-100.0 0.01-100.0 0.01-100.0 0.01-15.0 0.01-15.0 0.01-0.5 0.01-15.0 0.01-5.0

hydrocarbon liquid mixture are physically separated by gas chromatography and compared to calibration data obtained under identical operating conditions. A fLxed volume of sample in the liquid phase is isolated in a suitable sample inlet system and entered onto the chromatographic column. 3.1.1 Components nitrogen/air through n-hexane are individually separated with the carrier flow in the forward direction. The numerous heavy end components are grouped into an irregular shape peak by reversing direction of carder gas through the column by means of a switching valve immediately following the elution of normal hexane. (See Fig. 1.) Samples that contain no heptanes plus fraction are analyzed until the final component has eluted with no reverse of carder flow. 3.1.2 An alternative to the single column bacldlush method is the use of a precut column which is bacldlushed to obtain the heptanes plus as a single peak at the beginning of the chromatogram. Two advantages of the alternate method are as follows: (1) better precision in measuring the C7 plus portion of the sample and (2) reduction in analysis time over the single column approach by approximately 40 %. 3.2 The chromatogram is interpreted by comparing the areas of component peaks obtained from the unknown sample with corresponding areas obtained from a run of a selected reference standard. Any component in the unknown suspected to be outside the linearity range of the detector, with reference to the known amount of that component in the reference standard, must be determined by a response curve. Peak height method of integration can be used only if the chromatograph is operating in the linear range for all components analyzed. Linearity must be proved by peak height for all components when using peak height method.

~1~) D 2597 z i u~

~, tu LU

Column.--SiIcone 200/500, 30 ft. 1/8 in Oven Temperature--- 100"C Inlet Pressure--45 pslg Sample Size.-- 1 mlcmllter Deleclor Temperature--- 125"C Chart Speed.-- Frontal ROw lcm/min Reverse Flow 0.5 cm/mtn FIo Rate--- 23 ml/mi°

00,~la

FIG. 1 Chromatogrsm of Demethanized Hydrocarbon Liquid Mixture (Frontal Carder Gas Flow Through N-Hexane, Reverse Grouping Heptsnes Plus)

(See Section 6 for further explanation of instrument linearity check procedures.)

4. Significance and Use 4.1 The component distribution of hydrocarbon liquid mixtures is often required as a specification analysis for these materials. Wide use of these hydrocarbon mixtures as chemical feedstocks or as fuel require precise compositional data to ensure uniform quality of the reaction product. In addition, custody transfer of these products is often made on the basis of component analyses of liquid mixtures. 4.2 The component distribution data of hydrocarbon mixtures can be used to calculate physical properties such as specific gravity, vapor pressure, molecular weight, and other important properties. Precision and accuracy of compositional data are extremely important when these data are used to calculate physical properties of these products.

w

I

Column 1-- Silicone DC 200/500, 30 ft, 1/8in Column 2 - - Silicone DC 200/500, 1.5 fl, 1/8 in Oven Temperature.-- 125"C Inlet Pressure--- 95 psig Sample Size--- 0.5 microliter Detector Temperature-- 125"C

tu uJ ~_

~-

I

z ~

!11 1 z

.j

0

z~

w

~"

m

0

~z z

~

o

z

FIG. 2 Chromstogram of Demethanized Hydrocarbon Liquid Mixture (Precut Column Grouping Heptanes Plus, Frontal Carder Gas Flow Remaining Components)

5. Apparatus 5.1 Any gas chromatograph can be used that meets the following specifications. 5.1. I Detector--The detector shall be a thermal-conductivity type. It must be sufficiently sensitive to produce a deflection of at least 0.5 mv for 1 tool % of n-butane in a 1.0-~tL sample. 5.1.2 Sample Inlet System, Liquid--A liquid sampling valve shall be provided, capable of entrapping a fixed volume of sample at a pressure at least 200 psi (1379 kPa) above the vapor pressure of the sample at valve temperature, and introducing this fixed volume into the carder gas stream ahead of the analyzing column. The fixed sample volume should not exceed 1.0 IxL and should be reproducible such that successive runs agree within +2 % on each component peak area. The liquid sampling valve is mounted exterior of any type heated compartment and thus can operate at laboratory ambient conditions. 5.1.3 Sample Inlet System, Gas (Instrument Linearity)-Provision is to be made to introduce a gas phase sample into the carder gas stream ahead of the chromatographic column so that linearity of the instrument can be estimated from response curves. The fixed volume loop in the gas sample valve shall be sized to deliver a total molar volume approximately equal to that delivered by the liquid sample valve in accordance with 5.1.2. (See Section 6 for further explanation of instrument linearity check procedures.) 5.1.4 Chromatographic Columns: 5.1.4.1 Column No. I - - A partition column shall be provided capable of separating nitrogen/air, carbon dioxide, and the hydrocarbons methane through normal hexane. (See Figs. 1 and 2.) Separation of carbon dioxide shall be sufficient so that a 1-~tL sample containing 0.01 tool % carbon dioxide will produce a measurable peak on the chromatogram, (The silicone 200/500 column, containing a 27 to 30 weight % liquid phase load, has proven satisfactory for this type of analysis.) 5.1.4.2 Column No. 2--A partition column similar to Column No. 1. It shall be of the same diameter as Column No. 1. The column shall be of an appropriate length to deafly separate the heptanes plus fraction from the hexanes and lighter components. 5.1.5 Attenuator--A multistep device shall be included in the detector output circuitry to attenuate the signal from the detector to the recorder when using manual calculation methods. The attenuation between steps shall be accurate to -+0.5 %. 5.1.6 Temperature Control--The chromatographic column(s) and the detector shall be maintained at their respective temperatures, constant to -+0.3"C during the course of the sample and corresponding reference standard runs. 5.2 Carrier Gas--Pressure-reducing and control devices to give repeatable flow rates. 5.3 Recorder--A strip chart recorder with a full-scale range of I m v shall be required when using manual calculation methods. A m a x i m u m pen response time of I s and a minimum chart speed of I cm/min (0.5 in./min accepted) shallbc required. Faster speeds up to I0 cm/min (3 in./min accepted) are required if the chromatogram is to be interpreted using manual methods to obtain areas. 393

~ c,~lt *AIR ~s~

r~OATING

.¢,.itF

~

D 2597

C~mtl *At ro o~u~

interest. Specifically, components such as CO2 or aromatic hydrocarbons are partially soluble in many displacement liquids and thus can compromise the final analysis. This caution is of the utmost importance and should be investigated prior to utilizing this technique.

~

.ft.,t, u¢.¢~t¢,~.l~

6. Calibration

FIG. 3 RepressuringSystem and ChromatographicValvingwith Floating PistonCylinder NOTE 2--A strip chart recorder is recommended for monitoring the progress of the analysis if an electronic digital integrator without plotting capability is in service. 5.4 Electronic Digital Integrator--A strongly preferred and recommended device for determining peak areas. This device offers the highest degree of precision and operator convenience. NOTE 3: C~ution--Electronic digital integrators are able to integrate peak areas by means of several different methods employing various correction adjustments. The operator should be well versed in integrator operation, preventing improper handling and manipulation of data-ultimately resulting in false information. 5.5 Ball and Disk Integrator--An alternative device in the absence of an electronic digital integrator for determining

peak areas. This device gives more precise areas than manual methods and saves operator time in interpreting the chromatogram. 5.6 Manometer--Well type, equipped with an accurately graduated and easily readable scale covering the range from 0 to 900 m m of mercury. The manometer is required in order to charge partial pressure samples of pure hydrocarbons when determining response curves for linearity checks when using the gas sampling valve. 5.7 Vacuum Pump---Shall have the capability of producing a vacuum of 0.I m m of mercury absolute or less. Required for linearity checks when using the gas sampling valve. 5.8 Sample Filter--An optional device to protect the liquid sampling valve from scoring due to the presence of foreign contaminates such as metal shavings, dirt, etc., in a natural gas liquid (NGL) sample. The filter can be of a small total volume, or an in-line type design and contain a replaceable/disposable element. NOTE 4: Caution--A filter can introduce error if not handled properly. The filter should be clean and free of any residual product from previous samples so that a buildup of heavy end hydrocarbon components does not result. (Can be accomplished by a heating/cooling process or inert gas purge, etc.) The filter element should be 15-pm size or larger so that during the purging process NGL is not flashed, preventing fractionation and bubble formation. 5.9 Sample Containers: 5.9.1 FloatingPiston Cylinder--A strongly preferred and recommended device suitable for securing, containing, and transferring samples into a liquid sample valve and which preserves the integrity of the sample. (See Fig. 3.) 5.9.2 Double-ValveDisplacement Cylinder--An alternate device used in the absence of a floating piston cylinder suitable for securing, containing, and transferring samples into a liquid sample valve. (See Figs. 4 and 5.)

6.1 In conjunction with a calibration on any specific chromatography, the linear range of the components of interest shall be determined. The linearity is established for any new chromatograph and reestablished whenever the instrument has undergone a major change (that is, replaced detectors, increased sample size, switched column size, or dramatically modified run parameters). 6.1.1 The preferred and more exacting procedure is to prepare response curves. The procedure for developing the

data necessary to construct these response curves for all components nitrogen through n-pentane is set forth in Annex A2. 6.1.2 A second procedure utilizes gravimctdcaUy constructed standards of a higher concentration than is conmined in the unknown. A set of response factors arc first determined for all components by means of a blend mix. (See 6.3.) A second (or third) gravimetrically determined standard (either purity or blend) can then be run, using the originally obtained response factors,which contain a concentration of individual components exceeding the expected amounts in the unknowns. W h e n both (or all three) runs match their respective standards within the precision guidelines allowed in Section I0, then the instrument can bc considered linear within that range. NOTE 6--This test method omits the need of a gas sample valve on the chromatographic instrument. However, several accurate primary VENT PRESSURE REGULATOR

?

NE~Le @ ~ ~kJ..V[

NEELLE ~ VENT VAL'¢E~J CHROMATOGRAPH LIQUIO SAMPLING VALVE CYLINDER / ' OUTPUT VALtre ~

~.~q.IND[III | I GLYCOl. • OR I. wATrn

-_LAYffR._~ -,__.~..~...-• GLYCOt. : • OR .

CY~IN[H[R

NEEOLEVALVE ~ " ~~

NOTe 5: Caution--This container is acceptablewhen the displacement liquiddoes not appreciablyaffectthe compositionofthe sample of 394

I ~ CA~RIEh [ ~ GAS - - - , , r i~ ~ l ¢ ~ ~ CARRIER GAS TO CuLJMh

~

~--~'~CYUNOER NEEDLE VALVE

FIG. 4 RepressudngSystem and ChromatographicValvingwith Double-ValveDisplacementCylinder

~

D 2597

PRESSURE REGULATOR

.9

INERT GAS

standard composition be similar to the one shown in Table 2, or closely resemble the composition of expected unknowns. This approach is valid for all components that lie within the proven linear range for a specific gas chromatograph. Nffre 7--Check the reference standard for validity when received and periodicallythereafter. Annex AI details one procedure for making the validitycheck.

~ ( ~ NEEDLEVALVE

CYLINO(Rit 1 ;I'UIII

-..._:..

~[.v-coL I

6.3 Using the selected liquid reference standard, obtain a chromatogram as outlined in Section 7. 6.3.1 Determine peak areas (or peak heights) from the chromatogram for all components. These data shall be used to calculate response factors in accordance with 9.1. 6.3.2 Repeat 6.3 through 6.3.1 until a satisfactory check is obtained. Usually two runs will suffice.

!

.' o ~ . I • WATER '

it

.'YLINDER,J

I

1

7. Procedure

7.1 General--In the routine analysis of samples described in the scope of this procedure, it is possible to obtain all components of interest from a single run. Response factors, determined in duplicate runs on a selected reference standard, are used to convert peak areas (or peak heights) of the unknown sample to real percent. 7.2 Apparatus Preparation--With the proper column(s) and liquid sample valve in place, adjust operating conditions to optimize the resultant chromatogram. Using the reference standard, introduce the sample in the following manner. 7.3 Introduction of Sample: 7.3.1 Floating Piston Cylinders--For floating piston cylinders, refer to Fig. 3 and proceed as follows: connect a source of inert gas to Valve A so that pressure can be applied to the sample by means of the floating piston. Apply a pressure not less than 200 psi (1379 kPa) above the vapor pressure of the sample at .the temperature of the sample injection valve. 7.3.2 Thoroughly mix the sample. 7.3.3 Connect the sample end of the cylinder, Valve B, to

...~.~..-- <=-=-.. -.-.."

NEEDLE VALVEtG~ ~

.~,

((

~

igW

~ CYLINDER~ ~

CYLINDER

-.ouTPuT

(B) VALVE

NGL SAMPLE TO CHROMATOGRAPH FIG. 5

Alternate Repressudng System with Double-Valve Displacement Cylinder

NGL standards are required and the exact point at which nonlinearity occursis not determined.

6.2 For routine analysis using this procedure it is intended that calibration be accomplished by use of a selected reference standard containing known amounts of all components of interest. It is recommended that the reference TABLE 2 Component

Example of Response Factors Determined from Reference Standard

Mol ~ in Referenced Standard

Peak Area Referenced Standard Run

Nitrogen/air

0.10

Methane

1.49

355235521"4~

311

0

o°

o.5o

1588

Ethane

53.90

182108

Propane

28.05

122825

Isobutane n-Butane 2,2-Dlmethylpropene

3.05

15306

6.01

30834

Isopentane

1.00

5856

n-Pentene

2.00

12280

22 O,mot,,,bu=e

002

2,3-Dimethylbutane 2-Methylbutene 3-Methylpentane Cyclopentane

Mo/~ Response Factors (xl0 000)

1~I "3.2154 ,, 4.1948 ~53.90 = 2.9598 ~2 - 2.2837

x~ x~

= 1.4080 = 1.8368

×

- 1.39=

~ ~2 .

x~

~ = 1,9927 6.01 ~ = 1.9491 ~1.00 ,, 1.7077

= 1.2960 x ~ 2 = 1.0000 3.05.^ ~122825 = 0.8726 15306 ~ x = 0.8535 1. 2 ~ x~ = 0.7478

1"~

~

x~

" 1.5287 - 1.5152

0.64

4513

~

0.41

2401

N-Hexane

0.74

5064

~ 1 = 1.7076 ~0.74 = 1.4613

HeptanesPlus

2.09

395

~ ~

3.188.

132

1485112"094851

Relative Res Factor (Ca Reference Peak)

= 1.4181

" 1.4073

= 0.7132 = 05

~

x- ~

5

0.6210

= 0.41 122825 ~ x~ - 0.7477

5~ x ~ ~

x~

= 0.6399 = 0.6162

~

D 2597 is shown in Fig. 6.) Reversing carrier flow causes severe baseline deviations (see Fig. I). When using electronic digital integrators, exercise care to ensure integration does not occur until baseline is adequately reestablished. The resulting irregular shaped C7 plus peak is eluted over a period of time equivalent to time on forward flow minus the retention time for the air peak. Only after baseline is reestablished should the run be terminated and carrier flow returned to original direction. 7.4.2 An alternative to backflushing after normal hexane is the use of a precut column to group the C7 plus fraction at the beginning of the chromatogram as a single peak. (An acceptable valve configuration for the precut method is illustrated in Fig. 7.) The valve position is switched when normal hexane and lighter components have traveled through Column 2 and are in Column 1. At this point, heptanes and heavier components are retained in Column 2. When the valve is reversed, the heptanes plus fraction will elute from Column 2 first. Baseline must be clearly and distinctly established before elution of the C7 plus peak so an accurate measurement of this peak can be obtained. After the elution of n-hexane, terminate the run and return the valve to the initial position.

the inlet of the chromatograph liquid sample valve. All connections and tubing are to be made of material imper= vious to the sample composition and of as small diameter and shortest length of plumbing as is practical, thereby minimizing dead space, All tubing between sample cylinder and liquid sampling valve shall be the same diameter. 7,3,4 With Valve C closed) open Valve B to fill the sample valve and associated lines. 7.3.5 Slowly crack Valve C to purge the sample valve. When the purge is complete, close Valve C. Caution--Use extreme care to ensure that no flashing of sample occurs in the inlet sampling line and valve system, Always meter at sample purge Valve C, never at sample Valve B. The sample line and valve system should remain at 1379 kFa (200 psi) above the vapor pressure of the product. 7,3.6 Operate the liquid sample valve either manually or automatically to inject the liquid sample into the carrier gas flow immediately ahead of the chromatographic column. Actuate the sample valve quickly and smoothly to place the sample on the column all at once and to ensure continuous carrier gas flow through the column. 7.3.7 Double- Valve Displacement Cylinders--For doublevalve displacement cylinders refer to Figs. 4 and 5 and proceed as follows: Connect the sample Cylinder B to Cylinder A so repressurizing fluid can be entered into the bottom of Cylinder B. With this configuration the hydrocarbon sample is taken from the upper portion of the cylinder. Pressurize Cylinder A with an inert gas and maintain a pressure at least 200 psi (1379 kPa) above the vapor pressure of the hydrocarbon sample at operating conditions. Open the necessary valves to admit pressurizing fluid into the sample Cylinder B. 7.3.8 Mix the sample thoroughly by gently inverting Cylinder B several times. Fix the cylinder in a vertical position by means of a ringstand, or similar device. 7.3.9 Connect the sample outlet Valve B on Cylinder B to the inlet of the chromatograph liquid sample valve. All connections and tubing are to be made of material impervious to the sample composition and of as small diameter and shortest length of plumbing as is practical, thereby minimizing "dead space." All tubing between sample cylinder and liquid valve should be the same diameter. 7.3.10 With Valve C closed, open Valve B to fill the sample valve and associated lines. 7.3.11 Slowly crack Valve C to purge the sample valve. When the purge is complete close Valve C. Caution--Use extreme care to ensure that no flashing of sample occurs in the inlet sampling line and valve system. Always meter at sample purge Valve C, never at sample Valve B. The sample line and valve system should remain at 1379 kPa (200 psi) above the vapor pressure or the product. 7.3.12 Operate the liquid sample valve either manually or automatically to inject the liquid sample into the carrier gas flow immediately ahead of the chromatographic column. The liquid sample valve should be actuated quickly and smoothly to place the sample on the column all at once and to ensure continuous carrier gas flow through the column. 7.4 Valve Switching: 7.4.1 After the elution of n-hexane the carrier gas flow is reversed by means of a backflush valve operated manually or automatically. (An acceptable backflush valve configuration

8. Unknown Sample Run 8.1 Obtain a chromatogram of the unknown sample in accordance with instructions outlined in Section 7. 8.1.1 Determine peak areas (or peak heights) from the chromatogram for all components. These data shall be used to calculate composition of the unknown in accordance with instructions outlined in 9.2. 9. Calculation 9.1 Calculation of Response Factors Using a Known

Reference Standard: 9.1. I Determine the peak area (or peak height) of each component nitrogen/air through heptanes plus (if applicable) from the chromatogram of the known reference standard. NOTE 8--The backflush peak (where applicable) for heptanes plus is considered to be a single component for the purpose of this calculation. In addition, the peak area method shall be used in calculating the heptanes plus fraction.

9.1.2 Calculate a response factor for each of the preceding m[~*

e,)

rrngu*

r ~ll//

¢ota~ MliTIAI*

POllITiOU

FINAL

pOII'T~

FIG. 6 BackflushValve Configuration 396

q~) D 2597

INIJ[T STMAN ¢JkRNtI[R

¢umet e=|ITII~

MRp = mol percent of the component in reference standard

*m.gr

*tIt

~m

It

Precut Valve Configuration

components in accordance with the following equation (see Table 2): K =M

where: M = tool percent of component in unknown, P = peak area (or peak height) of each component in unknown sample, and K = response factor as determined in 9.1. 9.2.2.1 Total the tool percent values and normalize to 100 %. 9.2.3 Using the relative response factors calculate the concentration in tool percent of each of these components in accordance with the following equation (see Table 3):

(1)

where: K ffi response factor, M = mol percent of component in reference standard, and P = peak area or peak height in arbitrary units (miUimetres, square inches, counts, etc.) corrected to maximum sensitivity. 9.1.3 An alternative method of determining response factors is the use of a single reference component in the standard. Calculate a relative response factor for each component in accordance with the following equation (see Table 2):

KF, =

M, x

P~"

Pz

MRp

J~/z= KF; x P;

Component Nitrogen/Air Methane Carbon Dioxide Ethane Propane Isobutane n-Butane 2,2-Dimethylpropane Isopentane N-Pentane 2,2-Dimethylbutane 2,3-Dimethylbutane 2-Methylpentane 3-Methylpentane Cyclopentane n-Hexane Heptanes Rus

(4)

x ~oo

(KF, x P,) i--I

where:

M,

= mol percent of component i in unknown, -- relative response factor for component i, = peak area (or peak height) of component i P, . in unknown, and 2; (KFz × Pz) = summation of all relative response areas in z-~ the chromatogram. 9.2.3.1 Total tool percent values and normalize to 100 %.

(2)

KFi

where: KFz = relative response factor for component i, M; = mol percent of component i in reference standard, P, = peak area (or peak height) in arbitrary units corrected to maximum sensitivity for component i, t% = peak area (or peak height) of the component selected as the reference peak, and TABLE 3

known Sample: 9.2.1 Determine peak area (or peak height) of each component nitrogen/air through heptanes plus from the chromatogram of the unknown sample using the same arbitrary units as in 9.1. 9.2.2 Calculate the concentration in mol percent of each of these components in accordance with the following equation (see Table 3): M= Px K (3)

o=¢¢¢~1ll FIG. 7

as the reference peak. From the equation defining the relative response factor, the component chosen as the reference peak always has a response factor of 1.000. 9.2 Calculation of Mol Percent of Components in Un-

10. Precision and Bias 10.1 The precision of this test method as determined by

Calculation of Unknown Sample Using Response Factors from Table 2 Normalized Mol ~

RelativeResponse Factor (Cs Reference Peak)

0.02926 1.97995 0.83387 18.96936 25.88483 6.29494 6.56301

0.04 2.85 1.20 27.27 37.21 9.05 9.44

1.4080 1.8368 1.3963 1.2960 1.0000 0.8726 0.8535

128 8670 3651 83061 113346 27565 28739

0.04 2.85 1.20 27.27 37.21 9.05 9.44

1.7077 1.6287 1.5152 1.4181

2.79516 2.80706 0.01136 0.57107

4.02 4.04 0.02 0.82

0.7478 0.7132 0.6635 0.6210

12240 12292 50 2501

4.02 4.04 0.02 0.82

1584

1.7076

0.27048

0.39

0.7477

1184

0.39

4521 13335

1.4613 1.4073

0.66065 1.87663

0.95 2.70

0.6399 0.6162

2893 8217

0.95 2.70

Peak Area

MOI ~ Response Factor (xl0 000)

91 4720 2615 64090 113346 31590 33672

3.2154 4.1948 3.1888 2.9598 2.2837 1.9927 1.9491

16368 17235 75 4027

Unnormalized Mol •

t-0-0700

397

Unnormalized Area x RRF

~

Normalized Mol

V0O-~

~

D 2597

statistical examination ofinterlaboratory results is as follows: 10.l.1 Repeatability--The difference between two test results, obtained by the same operator with the same apparatus under constant operating conditions on identical test material, would in the long run, in the normal and correct operation of the test method, exceed the following values only in one case in twenty: Component Nitrogen Carbon Dioxide Methane Ethane Propane lsobutane n-Butane Isopcntane n-Pentane

Mol % Range 01-.89 01-2.3 1.6--4.5 27.-54. 28.-34. 3.0-8.8

Percent Relative Repeatability 9

6.0-9.3

1 2 2 2

1.0-3,9 2.0-3.8 3.6-5.7

of the test method, exceed the following values only in one case in twenty:

4 4

.5 .5

Mol % Range

Percent Relative Reproducibility

Nitrogen Carbon Dioxide

01-89 01-2.3

60

Methane Ethane Propane Isobutane n-Butane lsopentane n-Pentane C~"

1.6--4,5 27.-54. 38.-34. 3.0-8.8 6.0-9.3

10 2 2 4

1.0-3.9

6 6

Component

30

4

2.0-3.8 3.6-5.7

10

NOTE l l - - T h e repeatability and reproducibility statements for this procedure are from the statistical data obtained in a GPA cooperative test program completed in 1986. The testing program included six samples analyzed in a round robin by eight laboratories.

I

10.2 Bias--The bias of the procedure in this test method has not been determined but is now under consideration.

10.1.2 Reproducibility--The difference between two single and independent results obtained by different operators working in different laboratories on identical test material would, in the long run, in the normal and correct operation

11. Keywords 11. I chromatography; demethanized hydrocarbons; liquefied petroleum gases; natural gas liquids

ANNEXES (Mandatory Information) AI. FIDELITY OF SELECTED REFERENCE STANDARDS A I. 1 Referring to Section on Summary of Method, it is noted that the test method is based on response factors calculated from a selected reference standard using peak area measurements. Liquid reference standards are difficult to prepare and are subject to change in composition during use. Hence it is virtually mandatory that the reference standard be authenticated in some manner when received and periodically during use. One simple approach is described as follows: A l.l.l Determine mol percent response factors for normal hydrocarbons using area measurements of peaks recorded on chromatogram of reference standard run (see 9.1.2). Al.l.2 Determine molecular weight corresponding to each component hydrocarbon in Al. I. I. Al. 1.3 Using log/log paper plot the response factor on the

vertical scale versus molecular weights on the horizontal scale (see Fig. A 1.1). A I. 1.4 If all is in order the resultant plot will be essentially a straight line with a negative slope. For a specific instru-

I

!

i

u

l

I

I

I

t

I

I

u

5

-,~c,

Cl

TABLE A1.1

Response Factors and Mol Weights

Normal Hydrocarbon Components A Component

Response Factor x 10 -4

Mol Weight

Methane Ethane Propane n-Butane n-Pantane n-Hexane

4.195 2.960 2.284 1.949 1.629 1.461

16.043 30.070 44.097 58.123 72.150 86.177

t I

A Initially with a new system end a new blend this check should be performed often, say once s day for the first week to satisfy the operator that the component analysis fumished with the blend is essentially correct. After this time the check should be performed each time s calibration run is made to verify the continued fidelity of the selected reference blend.

Io

I

I

15

20

I

I

25 30

i

40

I

I

l

I

I

I

50 aO 70 1010100

leo

M~decdor weqlht FIG. A1.1

398

Response Factom (tool %) Versus Molecular Weight

o 2sgr ment, the angle of the plot should remain essentially constant. A change in the angle usually indicates a change in blend composition. AI.I.5 An example follows using data from Table 2 in this test method (see Table A I. 1). A1.2 It should be noted the relationship described AI. 1.1 to AI.I.5 is valid for reference blends in the vapor state as well as the liquid state, so long as the following conditions are met. A1.2.1 Chromatogram is obtained using a thermal conductivity detector.

AI.2.2 Peak areas in arbitrary units are used for peak measurements. AI.2.3 Known concentrations of hydrocarbon components in the known reference blend are expressed in mol %. A I.3 In addition to authentication of reported composition of a new blend and periodically verifying its validity, this plot can be used to: AI.3.1 Reduce the frequency of calibrations required. AI.3.2 Reveal calculation and interpretation errors in calibration runs. A1.3.3 Pick off factors for components not in the standard by extrapolating the plot. A factor for the back flush peak can be picked off if the molecular weight can be satisfactorily estimated.

A2. D E T E R M I N A T I O N OF RESPONSE FACTORS A2.1 Linearity Check A2.1.1 In order to establish linearity of response for the thermal conductivity detector, it is necessary to carry out the procedure outlined as follows: A2.1.2 The major component of interest (methane for natural gas) is charged to the chromatograph by means of the fixed-size sample loop at partial pressure of 100 to 700 m m of Hg in increments of 100 mm. The peak area of the methane is plotted versus partial pressure. Any deviation from linearity indicates the fixed volume sample loop is too large. The sample size should be reduced until the pure major component is linear over the concentration range expected in the samples. A2.1.2.1 Connect the pure component source to the sample entry system. Evacuate the sample entry system and observe manometer for any leaks. (See Fig. A2.1 for a suggested manifold arrangement.) The sample entry system shall be vacuum tight. A2.1.2.2 Carefully open the needle valve to admit the pure component up to 100 mm of partial pressure. A2.1.2.3 Record exact partial pressure and actuate sample valve to place sample onto column. Record peak area of pure component. A2.1.2.4 Repeat A2.2.3 for 200, 300, 400, 500, 600, and 700 mm of mercury. Record peak area obtained at each pressure. A2.1.2.5 Plot the area data versus partial pressure on the x and y axes of linear graph paper as shown in Fig. A2.2. NOTE A2.l--Experience has shown that if the major component is linear over the expected concentration range in the sample, the lesser components will also be linear. Methane and ethane exhibit less than 1% compressibilityat 760 mm Hg and are therefore the components of choice for linearity checks. NOTE A2.2: Caution--n-Butane at atmospheric pressure exhibits 3.5 % compressibility, which, if the detector response is linear, will produce a nonlinear response opposite to detector non-linearity.

standard and in the unknown samples lie within the proven linear range for a specific chromatography instrument. An acceptable non-routine method of determining response factors is to charge the pure components to the chromatograph. The latter method is described in Annex A I. A2.2. I. l Connect the reference standard gas to the sample entry system. Evacuate the sample entry system and observe the manometer for any leaks. A2.2.1.2 Carefully open the needle valve to admit reference standard gas up to some predetermined partial pressure. NOTE A2.3--The use of some constant partial pressure below atmospheric pressure avoids variations in sample size due to changes in barometric pressure. A2.2.1.3 Record the partial pressure and operate the gas sampling valve to place the sample onto the column. Record the chromatogram, integrator/computer peak areas, and peak retention times. NOTE A2A--It is recommended that the integrator/computer has the capability to print out retention times of peak maxima to aid in peak identification and to monitor instrument conditions for unknown changes. TO VACUUM

%MP

NEEOLE

GAS CHROMATOGRAPH SAMPLE

CYLINOER

VENT

SAMPLE VALVE

MANOMETER

Figure 6 Suggested Manifold Arrangement for Entering Vacuum Samples

A2.2 Calibration Procedure

A2.2.1 Response factors of the components of interest can be established in two ways. The routine method is to use a gas reference standard of known composition to determine response factors, provided all components in the reference

FIG. A2.1 SuggestedManifold Arrangement for Entering Vacuum Samples

399

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SO0

D 259"/'

Illlll[lltllll]llllllll II Ill Irll ,l!l[rt ii ~]lll I Ill 1111111bllllllllllkllll Illllllllllll!ll!!lilll ~' I[ll]l!llL41[!!lLlll[]l[[~l~14[ILIIILlllIIl[L]ll Ill LI I[iiil!l[[ll]ll][lll[]~'~[]l]l]llll]l[[ll]lllllll I][I liiill[lil[lllI[!illlli i ll!!iilli!ililllillllli ij[iill]ll[!lr[[iL~lllr]!lrii[[llIl[lirl[ll[lJlI Illll ,1[ ili!llliiilll[ll!I[!lli I[ [lill[[iili[iL~lrlrlllllllri[l[][ll[l[ll]lr[Ir[ll ,IIF li!iilli!llll!lllilllll li I[l!lll[[~l![[][]]ll[[ll[ll]lllJll[lllIIlllll[lltl Irl :1 iiiiilli!l!lil!!ll!llli !! I[il~[]iiilll[![]l[l[[ll[l]][[llll[[lt[l$1[]l;[I] I;ll !i!i!lLilLil!!lllLlIlll i ~ ~il[[[[[i[]]iL[l[l{ILl[l[ILIl![l[I]l!]L[lIllllt]LI LIll iii!ill[iii[lllll!I!i[i~ lil[:[:!ll:ii[irilii[l[][il[llill]liliilii[lllJlilll[I Ill ![[lilili]rlllr![~i! i~t!i,,i~sii[lJ!l[[[[] rl IlJl[[IIl]l II I[ll[I]ll llrl Illl[,[[[illll~]!l]i!illl] Jill[Ill[ lll[lllll[l[[ II Illl Ill I

700

600

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i 300

200

100

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IJ [ll[ii]i~l]lJ]llllli[]l[I [l[I][l[Jllil [l[]ll[lllllr[ I] IIII i ]ll]~lilll[lll])llt[lilli[ Illi[lilllll]l 1 ill]lll]l]l]l]lilll I]111 I ~1111i[il;[[1111[[11[;[11[[[[lllll[[[[;l[lll I[[lii[lil[]llil[l[$1[ll[[ I[I Illll II IIIIIILIIIIIIIlllll 1[l[141[L[l[IE II I[[lll[l[l[lllllll[IEIIEI ~l IIIIIllIIllllllllllllliillrllli I llllllllllilllllIlllllllllllllllllllllllllIIllllll lO,0OO

50,000 Area Counts

30,000

7O,0O0

9O,OOO

110,000

FIG. A2.2 Lineadtyof Detector Response

A3. PRECAUTIONARY STATEMENTS A3.2.3 Do not enter storage areas unless adequately ventilated. A3.2.4 Always use a pressure regulator. A3.2.5 Release regulator tension before opening cylinder. A3.2.6 Do not transfer to cylinder other than one in which gas is received. A3.2.7 Do not mix gases in cylinders. A3.2.8 Do not drop cylinders. A3.2.9 Make sure cylinder is supported at all times. A3.2.10 Stand away from cylinder outlet when opening cylinder valve. A3.2.11 Keep cylinder out of sun and away from heat. A3.2.12 Keep cylinder from corrosive environment. A3.2.13 Do not use cylinder without label. A3.2.14 Do not use dented or damaged cylinder. A3.2.15 For technical use only. Do not use for inhalation

A3.1 Flammable Liquefied Gases A3.1.1 Keep away from sparks and open flame. A3.1.2 Keep container closed. A3.1.3 Use with adequate ventilation. A3.1.4 Avoid buildup of vapors and eliminate all sources of ignition, especially nonexplosive electrical devices and heaters. A3.1.5 Avoid prolonged breathing of vapor or spray mist. A3.1.6 Avoid prolonged or repeated skin contact.

A3.2 Compressed Gases (Helium, Nitrogen) A3.2.1 Keep container closed. A3.2.2 Use adequate ventilation.

purposes.

400

fl~ D 2597 The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and ff not revised, either reepproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend, ff you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103.

401

(~)

Designation: D 2622 - 94

An American National Standard

Standard Test Method for Sulfur in Petroleum Products by X-Ray Spectrometry I This standard is issued under the fixed designation D 2622; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (4) indicates an editorial change since the last revision or reapprovai.

This standard has been approved for use by agencies of the Department of Defense. Consult the listing in the DoD Index of Specifications and Standards for the specific year of issue which has been adopted by the Department of Defense.

1. Scope 1.1 This test method covers the deterrnination of total sulfur in liquid petroleum products and in solid petroleum products that can be liquefied with moderate heating or dissolved in a suitable organic solvent. The applicable concentration range will vary to some extent with the instrumentation used and the nature of the sample. Optimum conditions will allow the direct determination of sulfur in essentially paraffinic samples at concentrations exceeding 0.0010 mass %. 1.1.1 Methanol containing fuels M-85 and M-100 may be analyzed with an accompanying loss of sensitivity and precision because of the more absorbing matrix caused by the high oxygen content of these fuels. M-85 is 85 % methanol-15 %gasoline, and M-100 fuel is 100 % methanol. Correction factors are applied to achieve these results. 1.2 This test method also covers the determination of sulfur in crude oil. (See 12. i.3.) 1.3 The preferred units are mass percent sulfur. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard information, see Note 1. 2. Referenced Document

2.1 ASTM Standard." D4057 Practice for Manual Sampling of Petroleum and Petroleum Products 2 3. Summary of Test Method 3.1 The sample is placed in the X-ray beam, and the intensity of the sulfur Ka line at 5.373 A is measured. The intensity of a corrected backgrounda measured at 5.190/~, or if a rhodium tube is used, 5.437 A is subtracted from this intensity. The resultant net counting rate is then compared to previously prepared calibration curves to obtain the concentration of sulfur in weight percent. NOT~ 1: Caution--Exposure to excessivequantities of X radiation is injurious to health. The operator must avoid exposing any part of his person, not only to primary X rays but also to secondary or scattered i This test method is under the jurisdiction of Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subeommittee D02.03 on Elemental Analysis. Current edition approved Feb. 15, 1994. Published April 1994. Originally published as D 2622 - 67. Last previous edition D 2622 - 92~L "Annual Book of ASTM Standards, Vo105.02.

radiation that might be present. The X-ray spectrometer should be operated in accordance with the regulations of recommendations governing the use of ionizing radiation. 4. Significance and Use 4.1 Knowledge of the presence of sulfur in petroleum products, especially fuels, helps predict performance charac. tefistics and potential corrosion problems. 5. Interferences 5.1 Elements that will change the mass absorption coefficient of the sample more than +5 % from the calibration standards will introduce errors in the determination of sulfur due to changes in the absorption of sulfur Ka radiation. This same effect will be seen when the carbon-hydrogen ratio varies from sample to calibration standard. Absorption effects of this type can largely be overcome by diluting the sample to such an extent that the absorbing elements no longer exhibit a significant absorption effect on the emitted sulfur radiation. Some commonly encountered interferences are given in Table 3. 6. Apparatus 6.1 X-Ray. Spectrograph, equipped for soft ray detection in the 5.37-A range. For optimum sensitivity to sulfur the instrument should be equipped with the following: 6. I. 1 Optical Path of helium. 6.1.2 Pulse-Height Analyzer or other means of energy discrimination. 6.1.3 Detector designed for the detection of long wavelength X rays. 6.1.4 Analyzing Crystal, suitable for the dispersion of sulfur Ka X-rays within the angular range of the spectrometer employed. Pentaerythritol and germanium are most popular although less reflective materials, such as EDDT, ADP, and quartz, may be used. 6.1.5 X-Ray Tube, capable of exciting sulfur Ko radiation. Tubes with anodes of rhodium, chromium, and scandium are most popular although other anodes may be suitable. 7. Reagents 7.1 Di-n-Butyl Sulfide--A high-purity grade standard, with a certified analysis, manufactured especially as a calibration material for this test method) 7.2 Sensitivity Standards (see 9.3)--Several liquid petroleum materials containing sulfur in concentrations approxi3 The proposed ASTM sulfur calibration standard, supplied by Phillips Petroleum Co., Bartlesville, OK, has been found satisfactory for this purpose.

402

D 2622

mately in the middle of each of the calibration graphs constructed in accordance with 9.2. NOTE 2--Calibration standards may be used for this purpose. Since it is desirable to discard standards after each determination, a lower cost material is suggested for daily use. 7.3 W h i t e Oil, containing less than 5 mg/L sulfur. 8. Sampling

8.1 Samples shall be taken in accordance with the instructions in Practice D 4057. 9. Calibration

9.1 Prepare calibration standards by the careful weight dilution of the certified di-n-butyl sulfide with white oil. Exact standards of approximately the sulfur concentrations listed in Table 1 are recommended. NOTE 3--It is recommended that calibrations up to 5.0 % sulfur be made and that samples with higher concentrations of sulfur be diluted to within this concentration range. 9.2 Establish calibration curve data by carefully measuring the net intensity of the emitted sulfur radiation from each of the standards by the procedure described in Sections 10 and 11. Plot the intensity, in terms of net counts per second, against sulfur concentration. For convenience and accuracy in reading the graphs, plot several concentration ranges: for example, 0 to 0.010 mass percent, 0.01 to 0.10 mass percent, 0,1 to 1 mass percent, and 1 to 5 mass percent. 9.3 To maintain the validity of the calibration curves with slight changes in instrument sensitivity, measure the sensitivity standard at frequent intervals during the course of a day's run. Carefully establish the counting rate of this standard by measuring its intensity at frequent intervals during the preparation of the calibration curves. Use the factor, derived from the measurements and defined in l 1.1, to determine the corrected net counting rate of each sample (see 11.2). It is convenient to use a petroleum product containing only its natural sulfur for this standard material. When the sulfur content of the sample varies greatly from that of the sensitivity standard, the sample can be compared to a material that has about the same sulfur concentration as the sample (Note 2).

NOTE 5wSuit~bility of any background setting will depend on the

X-ray tube anode employed. A wavelengthof 5.190 A is recommended where chromium or scandium is used whereas 5.437 A has been found suitable for rhodium. 2 0, peak and background, angles for various crystals are listed in Table 2. 10.5 If, from the measurements made in accordance with 10.3 and 10.4, the counting rate is higher than that of the highest point on the calibration curve, dilute the sample with white oil until the sulfur concentration is within the limits of the calibration curve and repeat the procedure described in 10.1 through 10.4. 10.6 Determine the corrected counting rate and calculate the concentration o f sulfur in the sample as described in 11.2 or 11.4. NOTE 6--1n samples which are essentially paraffinic in nature (that is, they are similar to the calibration standards) gross counting rates may be employed. The gross counting rate is corrected for daily variations in instrument sensitivityin the same manner as the net counting rate, and the corrected gross counting rate is compared to calibration curves prepared by plotting gross counting rates versus weight percent sulfur. 10.7 When the sample contains concentrations of interfeting substances higher than those listed in Table 3, dilute the sample by weight with white oil to concentrations below those listed. NOTE 7--The concentrations of substances in Table 3 were determined by the calculation of the sum of mass absorption coefficienttimes weight fraction of element for each element present. This calculation was made for dilutions of representative samples containing approximately 3 % of interfering substances and 0.5 % sulfur. The data collected showed reasonable X-ray results when the calculated sum of mass absorption coefficienttimes weight fraction was about

10. Procedure 10.1 Place the sample in an appropriate cell using techniques consistent with good practice for the particular instrument being used. Although sulfur radiation will penetrate through only a small distance in the sample, scatter from the sample cup and the sample may vary to such an extent that a specific amount or a minimum amount of sample must be used. 10.2 Place the sample in the X-ray beam and allow the X-ray optical atmosphere to come to equilibrium.

TABLE 2 Crystal NaCI (200) EDDT (020) ADP (101) Pentaerythritol (002) Quartz (101) Ge (111) Graphite (002) Graphite (002) (PG)

TABLE 1 Sulfur Standards Sulfur Concentration, mass %

Sulfur Concentration, mass %

Sulfur Concentration, mass ~;

0.005 0.010 0.025 0.050 0.075

0.100 0.250 0.500 ... .. •

1.0 2.0 3.0 4.0 5.0

10.3 Determine the intensity of the sulfur K a radiation at 5.373 A by making counting rate measurements at the precise angular settings for this wavelength. NOTE 4ult is suggested that a sufficient number of counts be taken to satisfy at least a 1.0 % expected coefficient of variation when practical. When sensitivity or concentration, or both, make it impractical to collect a sufficient number of counts to achieve a 1.0 % coefficient of variation, accepted techniques, which will allow the greatest statistical precision in the time allotted for each analysis, should be used. The coefficientof variation is calculated as follows: Coefficientof variation, % = (100 ~ s + Nt,)/(N, - Nb) (I) where: N, = number of counts collected at sulfur line, and Nb ffi number of counts collected at background wavelength in the same time interval taken to collect N, counts. 10.4 Measure background count-rate at a previouslyselected, fixed, angular setting, adjacent to the sulfur K= peak.

403

2# Angles for Various Crystals

2d (A)

SKa (5,373 A), *

Background (5.190 A), • (5.437A), *

5.6406 8.808 10.640

144.55 75.18 60.66

133.89 72.21 58.39

149.12 76.24 61,46

8.742 6.6872 6.532 6,708

75.85 106.93 110.08 108.45

72.64 101.81 105.23 101.38

76.92 108.97 112.08 108.29

6.74

105.72

100.71

107.55

q ~ D 2622 TABLE 3 Concentrationsof Interfedng Elements(Note 7) Element

Percent Tolerated

Phosphorus Zinc Barium Lead Calcium Chlorine Ethanol (Note 8) Methanol (Note 8)

0.3 0.6 0.8 0.9 1 3 8.6 6

4 to 5 % above the sum of mass absorption coefficient times weight fraction for the calibration standards. Absorption interferences are additive and they are only minimized by dilution, not completely eliminated. Table 3 is therefore to be used as a guide to concentrations that can be tolerated without significant error, not as an absolute quantity. NOTe 8--The concentrations of ethanol and methanol were calculated using a theoretical mixture of hydrocarbons and dibutyl sulfide to which ethanol (or methanol) was added until the sum of the mass coefficientstimes weight fractions increased by 5 %. In other words, the amount of ethanol (or methanol) which caused a negative 5 % error in the sulfur measurement was calculated. This information is included in Table 3 to inform those who wish to use Test Method D 2622 for determining sulfur in gasohol (or M-85 and M-100) the nature of the error involved. 10.8 Mix the blend, check it for complete homogeneity, and transfer it to the instrument for measurement. 10.9 Determine the sulfur content of the blend in the normal manner as described in 10.2 through 10.6 and calculate the sulfur content of the original sample as described in 10.4. 11. Calculation 11.1 Calculate the correction factor for changes in daily instrument sensitivity as follows: F = A/B (2)

(3)

Sulfur Content, mare %

Repeatability, mass %

0.0010 to 0.0049 0.0050 to 0.0149 0.0150 to 5.0

0.60 x % S 0.20 × % S 0.05 x % S

Sulfur Content, mass %

Reproducibility, mats %

0.0010 to 0.0049 0.0050 to 0.0149 0.0150 to 5.0

0.60 x % S 0.40 x % S 0.16 x % S

12.1.3 A task force consisting of four laboratories ran a mini round robin on seven crude oils containing sulfur in the range of 0.12 to 2.85 %. The Test Method D 2622 reproducibility for each crude was calculated and compared to round robin results. The calculated reproducibility was exceeded in only one case in fifty-six. It was therefore concluded that this test method was suitable for the determination of sulfur in the 0.12 to 2.85 % sulfur range in crude oil 12.2 B i a s - - S i n c e there is no accepted reference material suitable for determining the bias for this test method no statement on bias is being made.

where: = total counts collected at 5.373 A, total counts collected at 5.190 A, Sj and $2 = seconds required to collect C counts, R = corrected net counting rate, and F' = (counts/s at 5.373 A)/(counts/s at 5.190 A) on a sample containing no sulfur. 11.3 Applying the corrected net counting rate to the appropriate calibration curve, read and report the sulfur concentration in mass percent. 11.4 Calculate the concentration of sulfur in samples which have been diluted as follows:

CB

S, mass % = S b x [(Ws + We)/ Ws]

12. Precision and Bias 12.1 The precision of the method as obtained by statistical examination of interlaboratory test results is as follows: NOTe 10---The precision on methanol containing samples has not been determined. 12.1.1 R e p e a t a b i l i t y - - T h e difference between successive test results obtained by the same operator with the same apparatus under constant operating conditions on identical test material would, in the long run, in the normal and correct operation of the test method exceed the following values only in one case in twenty:

12.1.2 R e p r o d u c i b i l i t y - - T h e difference between two single and independent results obtained by different operatots working in different laboratories on identical test material would, in the long run, in the normal and correct operation of the test method exceed the following values only in one case in twenty:

where: A = counting rate of the standard as determined at the time of calibration, and B = counting rate of the standard as determined at the time of analysis. I 1.2 Determine the corrected net counting rate as follows: R = [(CK/S,) - (CBF'/S2)]F

where: Sb ffi mass % sulfur in diluted blend, W~ ffi mass of original sample, g, and We - mass of diluent, g. 11.5 Report this result as the sulfur concentration in mass percent. 11.6 When analyzing M.85 or M-100 fuels divide the result obtained in 11.5 as follows: (Note 9) S (in M-85), mass % = S, mass %/0.59 (5) S 0 n M-100), mass % ffi S, mass %/0.55 (6) NOTe 9--One laboratory compared the sulfur sensitivity for M-85 and M-100 fuels to the sulfur sensitivity for paraffin oils (Test Method D 2622) by theoretical calculation using the XRF-ll (Criu Software, Inc.) computer program. This laboratory and one other found agreement between the theoretical and measured factors, therefore creating these correction factors.

13. Keywords 13.1 analysis; petroleum; spectrometry; sulfur; x-ray

(4)

404

~

D 2622

The American Society for Testing and Materla/s takes no position respecting the vahdlty of any patent rights asserted in connection with any item mentioned in this standard, Users of this standard are express/y advised that determination of the vahdlty of any such patent rights, and the risk of infringement of such rights, are entirely their own responslbl/ity Thin standard is subfect to revision at any time by the responsible techmcal committee and must be reviewed every hve years and if not rewsed, either reapproved or withdrawn Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you should make your wews known to the ASTM Committee on Standards, 100 Barr Harbor Drive, West Conshohocken, PA 19428.

405

~l~

Designation: D 2650 - 93 Standard Test Method for Chemical Composition of Gases By Mass Spectrometry 1 This standard is issued under the fixed designation D 2650; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (~) indicates an editorial change since the last revision or reapproval.

1. Scope 1.1 This test method covers the quantitative analysis of gases containing specific combinations of the following components: hydrogen; hydrocarbons with up to six carbon atoms per molecule; carbon monoxide; carbon dioxide; mercaptans with one or two carbon atoms per molecule; hydrogen sulfide; and air (nitrogen, oxygen, and argon). This test method cannot be used for the determination of constituents present in amounts less than 0.1 mole %. Dimethylbutanes are assumed absent unless specifically sought.

NOTE l--Although experimental procedures described herein are uniform, calculation procedures vary with application. The following influences guide the selection of a particular calculation: qualitative mixture composition; minimum error due to components presumed absent; minimum cross interference between known components; maximum sensitivityto known components; low frequencyand complexityof calibration;and type of computingmachinery. Because of these influences, a tabulation of calculation procedures recommended for stated applicationsis presented in Section 12 (Table 1). NOTE 2--This test method was developedon ConsolidatedElectrodynamics Corporation Type 103 Mass Spectrometers. Users of other instruments may have to modifyoperatingparametersand the calibration procedure. 1.3 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For a specific precautionary statement, see Note 6.

3. Terminology 3.1 Definitions: 3.1.1 mass number or m/e value of an ion--the quotient of the mass of that ion (given in atomic mass units) and its positive charge (number of electrons lost during ionization). 3.1.2 parent peak of a compound--the peak at which the m/e is equal to the sum of the atomic mass values for that compound. This peak is sometimes used as 100 % in computing the cracking pattern coefficients. 3.1.3 base peak of a compound--the peak used as 100 % in computing the cracking pattern coefficient. 3.1.4 cracking pattern coefficient--the ratio of a peak at any m/e relative to its parent peak (or in some cases its base peak). 3.1.5 sensitivity--the height of any peak in the spectrum of the pure compound divided by the pressure prevailing in the inlet system of the mass spectrometer immediately before opening the expansion bottle to leak. 3.1.6 partial pressure--the pressure of any component in the inlet system before opening the expansion bottle to leak. 3.1.7 cracked gases--hydrocarbon gases that contain unsaturates. 3.1.8 straight-run gases--hydrocarbon gases that do not contain unsaturates. 3.1.9 GLC--a gas-liquid chromatographic column that is capable of separating the isomers of butenes, pentenes, hexanes, and hexenes. 3.1.10 /R--infrared equipment capable of analyzing gases for the butene isomers. 4. Summary of Test Method 4.1 The molecular species which make up a gaseous mixture are dissociated and ionized by electron bombardment. The positive ions of the different masses thus formed are accelerated in an electrostatic field and separated in a magnetic field. The abundance of each mass present is recorded. The mixture spectrum obtained is resolved into individual constituents by means of simultaneous equations derived from the mass spectra of the pure compounds.

2. Referenced Documents

2.1 A S T M Standards: D 1137 Method for Analysis of Natural Gases and Related Types of Gaseous Mixtures by the Mass Spectrometer2 D 1145 Method of Sampling Natural Gas 3 D 1247 Method of Sampling Manufactured Gas 3 D 1265 Practice for Sampling Liquefied Petroleum (LP) Gases (Manual Method)4 D 1302 Method for Analysis of Carbureted Water Gas by the Mass Spectrometer5

5. Significance and Use 5.1 A knowledge of the composition of refinery gases is useful in diagnosing the source of plant upsets, in determining the suitability of certain gas streams for use as fuel, or as feedstocks for polymerization and alkylation, and for monitoring the quality of commercial gases.

I This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee 1)02.04 on Hydrocarbon Analyses. Current edition approved Aug. 15, 1993. Published October 1993. Originally published as D 2650 - 67 T. Last previous edition D 2650 - 88. 2 Discontinued; see 1980 Annual Book of ASTM Standards, Part 26. a Discontinued; see 1986 Annual Book of ASTM Standards, Vol 05.05. '*Annual Book of ASTM Standards, Vols 05.01 and 05.05. s Discontinued; see 1968 Annual Book of ASTM Standards, Part 19.

6. Interferences 6.1 In setting up an analysis, it is possible that a constituent was ignored. Also, an impure calibration may have been used. The spectrum calculated from the composition

406

~@) D 2650 found is to, therefore, be compared with the observed spectrum of the mixture at masses independent of the original calculation. Differences so computed, called residuals, should as a general rule be less than 1% of the original mixture peak for an acceptable analysis. Masses suitable for this calculation are tabulated with each calculation procedure.

Run Number

Compound

I 2 3 4 5

n-butane n-butane

hydrogen n-butane hydrogen

lO. 1.2 If the 43/58 and 43/29 ratios of the firsttwo runs do not agree with 0.8 %, further runs must be made until agreement is attained, either by adjusting the temperature of the ionization chamber or by other techniques commonly used by the laboratory. In any case, the three 43/58 and 43/29 ratios must agree within 0.8 % and the three butane sensitivities within 1%. The two hydrogen sensitivities must agree within 1.5 %. A standard gas sample can also be used as an additional check. 10.2 Reference Standards--Check the entire range with the spectrometer evacuated. This check provides a blank or background spectrum. If the approximate composition of the mixture is not known, make a preliminary run over the entire operating mass range. If the composition is known, the necessary calibrating gases should have been run recently enough before the mixture to preclude pattern changes. The calibrating gases should be run in order of decreasing molecular weight. If isomers are present, do not run them in succession. Introduce the calibrating gases through the inlet system at a pressure closely approximating that used for the mixture spectrum. It is important that the recordings of the mass spectra of the calibrants and the gas mixture begin at the same ion accelerating voltage, the same magnetic field, and at the same interval after opening the sample volume to the leak manifold. 10.2. I Run the hydrocarbon calibration gases as follows: introduce sufficient sample into the evacuated inlet system to give 4 to 6.7 Pa (30 to 60 mtorr) pressure in the expansion reservoir of the instrument (Note 6). Adjust the magnetic field and the ion-accelerating voltage for the range role 2 to 4 on the collector. Open the valve between the expansion reservoir and the leak manifold. One minute later, start the recorder and sweep. After sweeping over the above range, stop the sweep and recorder and quickly adjust the magnetic field and ion-accelerating voltage for the range role 12 to 100. Two minutes after admission of sample to the leak, start the recorder and sweep. After sweeping m/e = 100, pump out the reservoir and leak manifold. At least 5 rain of pumping time should be allowed between each run. NOTE 6: Warning--Samples and reference mixtures are extremely flammable. Keep away from heat, sparks, and open flames. Use with adequate ventilation. Cylinders shall be supported at all times. Hydrocarbon vapors that may be vented shall be controlled to assure compliance with applicable safety and environmental regulations. 10.3 Calibration DatamAfter the peaks of the calibration spectrogram have been measured, recorded, and corrected for background, transform them into a state appropriate for further computation. Obtain the sensitivities if desired by dividing the number of divisions of the base peak by the recorded sample pressure in the expansion reservoir of the mass spectrometer. Repeat the procedure for each calibrant.

NOTE 3--Another strategy employed to reduce interferences and increase accuracy consists of using spectra which have been corrected for contributions caused by the rare isotopes of carbon and hydrogen.

7. Apparatus

7.1 Mass Spectrometer--Any mass spectrometer can be used with this test method that shall be proven by performance tests described herein. 8. Reference Standards 8.1 The mass spectrometer must be calibrated with each of the components constituting the unknown mixture to be analyzed. The calibrating compounds must be of the highest possible purity. 6 Calibrants may be prepared in the laboratory doing the analysis or purchased ready for use. In general, the mass spectrometer is capable of detecting impurities in calibrants and the contribution of such impurities to the calibration spectrum can be removed. NoTe 4--Some of the calculation procedures require the use of combined spectra, for example, air and butylenes. Three frequently used possibilities for producing combined spectra are as follows: (1) Representative fraction from a specificsource, (2) Multiplication factors to convert the spectrum of a pure constituent to a simulated spectrum of the mixture, and (3) Proportionality factors for combining actual calibrations. A recommended concentration limit for combined mixtures is given. At the level recommended, the residual spectrum contribute less than 0.1% error in any one result when the concentration of any constituent in the combined mixture is doubled. 9. Sampling 9.1 Samples shall be collected by methods known to provide a representative mixture of the material to be analyzed. Samples can be collected in accordance with Method D 1145 or Methods D 1247 or D 1265. 10. Calibration and Standardization 10.1 Apparatus--Determine whether operating conditions remain normal by making certain tests periodically, following instructions furnished by the manufacturer of the apparatus. Include in these tests rate of leak, ion-beam control settings, pattern reproducibility, and galvanometer calibrations. 10.1.1 To ascertain pattern stability, the following schedule is provided both for laboratories that have mass spectrometers with conventional temperature control and for laboratories that vary the temperature of the ionization chamber to obtain constant patterns:

11. Procedure 11.1 Introduce the sample without fractionation (see Section 9). Obtain the mass spectrum of the mixture under the same conditions as the calibration spectra (see Section 10).

Research grade hydrocarbons from either Philips Petroleum Co., Bartlesville, OK, or American Petroleum Institute Standards Reference Office, Carnegie Mellon University, Pittsburgh, PA, have been found satisfactory.

407

t{~) D 2650 List the peak heights of the spectrum along with the appropriate role value. 12. Calculation 12.1 Schemes for calculating specific mass spectrometer gas analyses are shown in Table 1. Each results in a report of analysis on the samples as received in mole (gas-volume) percent unless otherwise noted. These schemes are possible procedures from which the user can make a choice on the basis of his particular problem. The calculation basic to all mass'spectrometric gas analysis is the solution of simultaneous equations. These are constructed in accordance with Eq 1:

coefficients may be used instead of the a u in which case this step is not applicable. The sum of the partial pressures should agree within 1% with the pressure measured in the expansion reservoir of the mass spectrometer unless water vapor is present in the sample. Divide each partial pressure by the total calculated pressure and multiply by 100 to obtain mole percentages. 13. Report 13.1 Results shall be reported in mole (gas-volume) percent correct to one decimal place. Comments shall appear on the form in the event the sample is not reported on an "as received" basis. In any event the serial number of the calculation procedure shall appear on a report of analysis.

m t = ~a o x xy (1) where: ml = mixture peak height at the ith m ] e used, a;j = pattern coefficient for the jth component on the ith peak, and xj ffi corrected base peak height of component j. These equations will be solved, where indicated by the Unicomponent Peak Method: Xj = (my - ~'i -I ajk × Xk)/ao

14. Precision and Bias 14.1 The precision of this test method as determined by statistical examination of interlaboratory results is as follows: 14.1.1 Repeatability--The difference between two test results, obtained by the same operator with the same apparatus under constant operating conditions on identical test material, would in the long run, in the normal and correct operation of the test method, exceed the values shown in Tables 2 and 3 only in one case in twenty. 14.1.2 ReproducibilitymThe difference between two single and independent results obtained by different operators working in different laboratories on identical test material would, in the long run, in the normal and correct operation of the test method, exceed the values as shown in Tables 2 and 3 only in one case in twenty.

(2)

where k = 1 refers to the heaviest component. Where simultaneous solution is indicated, a variety of direct arithmetic procedures may be used interchangeably. 7 Where increased precision or error control has been specified in this test method, more complex calculations must be used) In each of the above calculations, the xj's must be divided by the sensitivity for j to get partial pressure. Sensitivity

NOtE 7 - - T h e precision for this test method was not obtained in accordance with RR:D02-1007.

14.2 B i a s - - A bias statement cannot be determined because there is no acceptable reference material suitable for determining the bias for the procedure in this test method.

7 Crout, P. D., "A Short Method for Evaluating Determinants and Solving Systems of Linear Equations with Real or Complex Coefficients," Marchant Calculating Machine Co., Bulletins MM.182 and 183, ASTBA, September 1941. Dwyer, P. S., Psyvhometria, Vol 6, 1941, p. 101. Hotelling, H., Am. Math. Star., Vol 14, 1943, p. 1. s "Triangular Inverse Method," Analytical Chemistry, Vol 30, 1959, p. 877.

15. Keywords 15.1 gas analysis; gas composition; mass spectrometry

408

o 26s0 TABLE 1

Calculation Procedures for Mass Spectrometer Gas Analysis

NOTE--Coding of calculation procedures is as follows: O = Order peaks are used in the calculation expressed serially from 1 to n, n being the total number of components. P = r o l e of peak used and prefix, M, if monoisotopic. M = Method of computation U = Unicomponent Peak Method M, = Simultaneous equations where "a" identifies the particular set of equations if more than one is used. C = Chemically removed. Residual = m/e~of peak suitable as an independent check on the method. Sedal No . . . . . . . . . . . Name or Application Component

1

2

3

4

5

6

D 1137 A Natural Gas

D 1302 `= Carbureted Water Gas

H2-Ce

Reformer Gas

Ca,C4

iC4

O

Hydrogen Methane Ethylene Ethane Propane Propane Butediene Butane-1 Butene-2 Isobutene Isobutane n-Butane Pentenes Isopentane

.

P .

.

. .. .

M .

15 '16 U 13 27 M2 12 30 M2 10 42 M2 9 29 M2 . . . . . .. . 8 56 M2 8 56 M2 8 56 M2 7 43 M2 6 58 M2 ......... . . . . . .. . 4 72 M2 ......... ......... . . . .,.. . 5 57 M2

n-Pentane

Benzene Hexanes C6 cyclic paraffins Hexanes Toluene Hydrogen sulfide Carbon dioxide Carbon monoxide Nitrogen Air Helium

" '2' "3"4' M1 11 44 M2 . . . . . .. . 14 28 M2 3 32 M1 4 U 1

Serial No . . . . . . . . . . . .

7 Commercial Propane

Name or Application

M

Oc

2 Wle 27 30 42 29 ...... 56 56 56 ...... 58 70

M M M M M M

16 15 13 12 8 3 3 9 10 11 4 5 2 6 7 7

72 ...... ...... ...... ...... ...... ...... 44 12 14 32 ......

E

4 43 2 58 ......... .........

M M M M M

P

M

Oc

17 16 15 13 12 14 10 8 8 8 11 6 9 7 5 4

2 16 26 30 42 29 54 56 56 56 43 58 55 57 72 78

M M M M M M M M M M M M M M M M

0 0 0 0 6 9 9 8 4 5 7 2 3 1

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...... 42 M 29 M 3 29 M ... M ...... M ...... M 41 M 56 M ...... M . . . . . . M 39 M 43 M 2 43 M 58 M 1 58 M ...... M 70 M 72 M

1

32

M2 M2 M2 M1 M1 U M1 M2

. . . . . . . . . . . .

7 1 1 1 1 1 14 14 14

M M M U

O

U U U U M2 M1

...... 71 ...... ...... ... ... 28 ...... ......

3 2 1 21 20 18 19 22 o

U

C C U

pc

M

O

P

iii

M

iii

M

M

84 86 92 34 44 28 14 32 o

M M M M M M M M

U

. . . . . . . . .

10

11

12

13

Commercial Butane

Dry Gas Cracked Fuel Gas

Mixed Iso and Normal Butanes

Reformer Make-Up Gas

Unstabilized Fuel Gas

O

1 1 1 5 2 6 3

7

M

9

P

M

56 56

Oc

pC

M

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . M M

#

56 56

U

2 16 26 30 42 44 ...... 41 55 56 M43 58 70 M57 72 ......

BB Stream (Cracked Butanes)

O

1E

U U

pc

8

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . '7"26 M . . . . . . . 6 30 M 5 42 M 7 42 3 44 M 4 44 1 1

U U U

......

Hydrogen Methane Ethylene ~ Ethane Propone Propane Butadiene Butene-1 Butene-2 Isobutene Isobutane n-Butane Pentenes Isopentane n-Pentane Benzene

o

M

P

6 7 12 8 11 9 9 5 5 5 5 4 3 3 2 2 2 2 2 2 2 10 13 14 1 I

Component

o

P

O

M M

E

E

43 58 70 57

M M M M

6 4 1 7 8 9 5 2 F 3

42 44 54 41 56 39 43 58 70 57

M M M M M M M M U M

. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

409

O 15 14 12 11 10 7 3 1 1 1 8 4 9 5 6 . . . . .

P

M

2 M 16 M 26 M 30 M 42 M 44 M 54 M . . . . . . . 56 M E 43 M 58 M 70 M 57 M 72 M . . . . . .

O

P

M

......... ......... ......... .........

P

M

Oc

pC

M

10 2 9 16 ......... 7 30

O

M M

16 15 13 12 8 6 2 9 10 11 7 3 ... 4 5 H

2 16 26 30 42 44 54 41 56 39 43 58 70 57 72 H

M M M M M M M M M M M M U M M D

3 44 M 5 44 .................. . . . . . . . . . . . . . . . . . 4 1 .

.

43 58 .

.

.

.

.

.

M M .

6 2 3 4

2 57 M .................. . . . . . . . . . . . . . .

43 58 57 72

M M

M M M M

(@) D 2 6 5 0 TABLE 1 Serial No . . . . . . . . . . Name or Application Component Hexanes Ce cyclic paraffins Hexanes Toluene Hydrogen sulfide Carbon dioxide Carbon monoxide Nitrogen Air Acid Gases Residual ~ Residual ~ Residual ~ Residual ~

Continued

7

8

9

10

11

12

13

Commercial Propane

Commercial Butane

BB Stream (Cracked Butanes)

Dry Gas Cracked Fuel Gas

Mixed Iso and Normal Butanes

Reformer Make-Up Gas

Unstabilized Fuel Gas

O

P

M

O

P

M

Oc

pC

M

O

P

M

Oc

pC

. . . . . . . . . . . . . . . . . .

H

H

D

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

..................

H

H

O

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . .

H

H

O

. . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . .

H

H

D

o

o

c

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

.................. ::: ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

::.

. . . . . . . . . . . . . . . . . . . . . . . . . . .

8 27 M 8 9 29 M 9 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Serial No . . . . . . . . . Name or Application

27 29 . . . . . . . .

M M . . . . . . . .

10 27 11 29 . . . . . . . .

'~1' M

O

P

M

O

'o" o 13

::: ... 28

"C:' C M

......... ......... .........

o

2 e 16 17 18 19

32 ... 14 15 27 29

M C M M M M

......... 5 27 6 29 .........

P

M

'~' '~' 'c'

M M

. . . . . . . . .

o

C

o

o

C

8

28

M

14

28

M

1 o 11 12 13 14

32 o 14 15 27 29

M C M M M M

1 o 17 18 19 20

32 o 14 15 27 29

M C M M M M

14

15

16

H=-Ce Cracked Gas

H2-Ce Straight Run Gas

Light Refinery Gas

Component

O

P

M

O

P

M

O

P

M

Hydrogen Methane Ethylene Ethane Propane Propane Butadiene Butane-1

1 2 4 7 11 6 15

2 16 26 30 42 29 54

M M M M M M M

1 2

2 16

M M

"5'

30

M

20 17 14 13 12 10

2 16 26 30 42 29

U M M M M M

16'

'5.6'

'M"

iii

iii

iii

'1'1"

"i6"

"M'

'1'2" 18 21 17 22

.4'3 58 70 57 72

"M' M M M M

"'9' 14

"4"3" 58

'M" M

9

'2'3"

.6"4'

"M"

Buten -2 Isobutene Isobutane n-Butane Pentenes Isopentane n-Pentane Benzene Hexanes

c, cyolic pare.ins

. . . . . . . . .

Hexanes Toluene Hydrogen sulfide Carbon dioxide Carbon monoxide Nitrogen

. . . . . . . . .

Water Cyclobutane Cyclopentene Pentadienes Cyclopentane Methylmerceptan Ethylmercaptan Residual 41 Residual 14

""4' . .

29 .

.

.

.

M .

.

.

'1'3" 18 19

57 72 78

M M M

"2"0"

'8'4'

"M"

17 21 7 10

71 92 34 44

M M M M

".9' 13

3"4" 44

'M' M

".6'

2.6'

"M.

8

32

M

".6'

'3'2"

"M"

3

18

M

3 12

18 56

M M

M M

.

.

.

.

.

.

.

.

.

.

20 67 20 67 . . . . . . . . . 14 48 19 62 10 41 24 14

M M M M

.

.

.

.

.

.

1"6' 11 15 8 22

.

.

.

.

.

.

.

.

'7'0' 48 62 41 14

.

.

M

43"

M

8

58

M

15 7 6 5 4

70 57 72 78 84

M M M U U

• .3 "1

.6.6 .3.4.

.u.

16 18 19 2

44 12 28 32

U U U U

.

"IVI' M M M M

A Method D 1137. a Method D 1302. c The mass spectrometer analysis for isomeric butenes is far less accurate than for the other hydrocarbon components. The inaccuracies involved in the isomeric butene analysis by mass spectrometer range from 1.0 to 4.0 mole ~, depending upon the concentration, ranges, and extent of drifts in instrument calibrations. These inaccuracies will range still higher when pentenes are present in larger than 0.5 ~ concentrations. See A n a l y t i c a l C h e m i s t r y , Vo122, 1950, p. 991; I b i d , Vol 21, 1949, p. 547; and I b i d , Vol 21, 1949, p. 572. o In Method 4, butylenes and pentenes spectra are composites based on typical GLC analyses. Hexene and hexane spectra ere from appropriately corrected spectra of representative fractions. E Butenes are grouped if they are less than 5 ~. F If pentanes exceed 1 ~, they are determined by other means and the spectrum removed from the poly spectrum. o Chemically removed. H Removed from sample by distillation. i Residuals Groups A: r o l e 72, 58, 57, 44, 43; Group B: r o l e 56, 42, 30, 29, 14. All Group A residual shall be 0.2 division or less with the residual of the largest peak also being less then 0.3 ~ of its total peak height. All Group B residuals shall be less than 1 ~ of the peak height or 0.2 division, whichever is greater.

410

~ TABLE 2

D 2650

Summary of Results of Sample Calculated by Scheme 16 Mo~e percent, ~,,A ORB Average

Component Hydrogen Methane Ethylene Ethane Propyione Propane Butylenes Isobutane Normal butane Pentenes Isopentane Normal pentane

Nitrogen/carbon monoxide Carbon dioxide Hydrogen sulfide

20.6 34.1 5.4 12.4 7.9 5.8 2.6 2.5 1.2 0.4 0.5 0.1 0.5 0.2 5.8

Number of laboratories Number of analyses

14 23

0.2 0.4 0.1 0.1 0.1 0.3 0,1 0.1 0.1 0.1 0.1 0.0 0.1 0.0 0.1

2.2 1.4 0.2 0.9 0.6 0.3 0.2 0.4 0.2 0.1 0.2 0.2 0.5 0.2 0.9

6 15

14 23

A at repeatability standard deviation. B cR reprodudbility standard deviation.

TABLE 3

Precision of Procedures for Mass Spectrometer Analysis

Serial No . . . . . . . . . . Name

.

.

.

.

.

.

.

.

.

.

.

.

Component Hydrogen Methane Ethylene Ethane Propene Propane Butane-1 Butane-2 Isobutane n-Butane Pentenes Isopentane n-Pentane Hexanes Carbon dioxide Nitrogen Cydopentane Degrees of Freedom

1

14

D 1137 Natural Gas A

H=-Ce Cracked Gas

Repeatability

. 0.2 . 0.1 0.02 0.02 . . .

Reproducibility

.

.

.

.

Composition

Repeatability

12.581 16.333 2.116 7.367 7.883 6.601

0.14 0.20 0.08 0.10 0.16 0.12

. 0.5

.

.

.

.

. 0.3 0.04 0.06

. . .

. . .

. . .

.

.

.

.

. . .

. . .

. . .

. . .

.

.

. . . 0.02 0.2 . . . 50 Laboratories

.

. . .

. . . .

°

. . .

. .

. . 0.03 0.3

.

.

-

~

5.333 .

. . .

. .

-

. .

.

.

.

.

.

_

_

6.528

0. 8

1.484 1.015 1.270 0.116 0.123

0.09 0.10 0,11 0.05 0.02

32.146

().53 0.01

0.038 .

.

.

A Method D 1137.

APPENDIX (Nonmandatory Information) Xl. REFERENCE STANDARDS FOR PROCEDURES 14 AND 15 XI.I Butenes--Butene-1, butene-2, and isobutene may be averaged '/3, '/3, '/3. However, when a straight average is applied, limit the butenes total to l0 to 15 mole % to hold maximum error of lighter components to +0.5 mole % and limited to 5 mole % to keep maximum error of lighter components to +0. l mole %. For a more accurate determi-

nation of lighter components, for example, ethylene, nitrogen, propylene, and propane--gases from representative refinery streams, are to be run by a GLC or IR method to obtain ratios of the butenes present. Weighted sensitivity coefficients allow accurate analyses for lighter components plus accurate total butene content through a 0 to 100 % 411

t~) D 2650 butene range. The continued accuracy obtained depends upon the stability of the refinery operation units; therefore, checks from time to time by an independent method (GLC or IR) enable mass spectrometric data processing groups to know the margins of error or to obtain new weighted sensitivity coefficients to maintain low deviations. XI.2 Pentenes--Utilize weighted sensitivity coefficients at all times when pentenes content is likely to be above 1 mole %, due primarily to error caused in propane and propylene analysis. X 1.2.1 Gases from representative refinery streams can be run by a GLC method to obtain pentene ratios which then can be used to calculate weighted sensitivity coefficients. Alternatively, a C5 cut could be obtained from a lowtemperature fractional distillation of a sample of the type to be analyzed. The mass spectrum of this cut is recorded and the contributions of the normal and isopentane and normal butane present removed from the spectrum. The residual spectrum is typical of the pentenes present in samples of this

type. X1.2.2 Obtain checks from time to time on the pentene ratios to maintain low deviation. X I.3 Hexenes--Obtain weighted sensitivity coefficients as explained in X I.2 for pentenes. However, a C6 fraction from low-temperature distillation will be difficult to correct for pentenes present and if this approach is utilized it is suggested that a total C6's residual spectrum be calculated rather than attempting to correct out the C6 saturates. If a C6 fraction is used, regard samples with more than l mole % of C6's as inaccurate due to errors possible in incorrectly removing C6 contributions to lighter components. X I.3.1 If weighted sensitivities are employed, regard samples with over 2 mole % of C6 as inaccurate due to probable variations in refinery units operation, since most operation units try to keep C6's to a minimum in gas streams. X I.4 Hexanes--Obtain weighted sensitivity coefficients as described in X 1.3. The amount of hexanes present in a gas sample are not to exceed l mole %, otherwise regard the analysis as inaccurate as described in X I.3.

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103.

412

Designation: D 2710 - 92 (Reapproved 1994) ~1

®

An American National Standard

Designation: 299/92

Standard Test Method for Bromine Index of Petroleum Hydrocarbons by Electrometric Titration I This standard is issued under the fixed designation D 2710; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year oflast revision. A number in parentheses indicates the year oflast reapproval. A superscript epsilon (() indicates an editorial change since the last revision or reapproval. (INOT~--Seetion 11 was added editorially in October 1994.

1. Scope 1.I This test method covers the determination of the amount of bromine-reactive material in petroleum hydrocarbons and is thus a measure of trace amounts of unsaturates in these materials. It is applicable to materials having bromine indexes below 1000. 1.2 This test method is applicable only to essentially olefin-free hydrocarbons or mixtures that are substantially free from material lighter than isobutane and have a distillation end point under 288"C (550"F). 1.3 The values stated in SI units are to be regarded as standard. The values stated in inch-pound units are for information only. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements, see Sections 7, 8, and Annex A3.

D 1492 Test Method for Bromine Index of Aromatic Hydrocarbons by Coulometric Titration 3 3. Terminology 3.1 Definition: 3.1.1 bromine index--the number of milligrams of bromine that will react with 100 g of sample under the conditions of the test.

4. Summary of Test Method 4.1 A known mass of the sample dissolved in a specified solvent is titrated with standard bromide-bromate solution. The end point is indicated by a dead stop electrometric titration apparatus, when the presence of free bromine causes a sudden change in the electrical conductivity of the system. 5. Significance and Use 5.1 This test method provides a measure of trace amounts of unsaturated hydrocarbons in petroleum distillates boiling up to 288"C (550"F). An estimate of the quantity of these materials is useful in assessing the suitability of the lighter fractions for use as reaction solvents.

N o t e l - - T h i s procedure has been cooperatively tested on materials with b r o m i n e indexes in the range from 100 to 1000. These materials

include petroleum distillates such as straight-run and hydrocracked naphtha, reformer feed, kerosine, and aviation turbine fuel. NOTE2--Materials with bromine index greater than 1000 should be tested for bromine number using Test Method D 1159/IP 130. Note 3mlndustrial aromatic hydrocarbons should be tested using Test Method D 1492.

6. Apparatus 6.1 Dead-Stop Electrometric Titration Apparatus--Any dead-stop apparatus can be used incorporating a highresistance polarizing current supply capable of maintaining approximately 0.8 V across two platinum electrodes and with a sensitivity such that a voltage change of approximately 50 mV at these electrodes is sufficient to indicate the end point. The procedure described is based on the electric eye circuit (Annex A l) which has been found satisfactory in operation. Other types of commercially available electric titrimeters, including certain pH meters, have also been found to be suitable. An alternative transistorized circuit is described in Annex A I. The components for this circuit are now more readily available than those for the electric eye circuit. It has been demonstrated that the results obtained are

2. Referenced Documents

2.1 A S T M Standards: D 1159 Test Method for Bromine Number of Petroleum Distillates and Commercial Aliphatic Olefins by Electrometric Titration 2 i This test method is under the jurisdiction of ASTM Committee 13-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.04.OD on Physical Methods. Current edition approved Dec. 2, 1992. Published February 1993. Originally published as D 2710 - 68. Last previous edition D 2710 - 89. in the IP, this test method is under the jurisdiction of the Standardization Committee. 2 Annual Book of ASTM Standards, Vol 05.01.

comparable. 6.2 Titration Vessel--A jacketed glass vessel of approximately 150-mL capacity of such a form that can be conve3 Annual Book of ASTM Standards, Vol 06.04.

413

f@) O 2710 niently maintained at 0 to 5°C (32 to 41*F). A pair of platinum electrodes spaced not more than 5 mm apart, shall be mounted to extend well below the liquid level. Stirring shall be by a mechanical or electromagnetic stirrer and shall be rapid, but not so vigorous as to draw air bubbles down to the electrodes. 6.3 Burets, 10 and 50-mL capacity. 6.4 Iodine Number Flasks, glass-stoppered, 500-mL capacity.

- (~)

299

NOTE 4: Warning--Poison. Combustible. May be fatal if swallowed. Causes severe burns. Harmful if inhaled. See A3.1. NOTE 5: WarningMPoison. Corrosive. May be fatal if swallowed. Liquid and vapor cause severe burns. Harmful if inhaled. See A3.2.

7.3.2 Potassium Iodide Solution (150 g/L)wDissolve 150 g of potassium iodide (KI) in water and dilute to 1 L. 7.3.3 Sodium Thiosulfate, Standard Solution (0.05 N ) - Dissolve 12.5 g of sodium thiosulfate pentahydrate (Na2S203.5H20) in water and add 0.01 g of sodium carbonate (Na2CO3) to stabilize the solution. Dilute to 1 L and mix thoroughly by shaking. Standardize by any accepted procedure that determines the normality with an error not greater than +0.0002. Restandardize at intervals frequent enough to detect changes of 0.0005 in normality. 7.3.4 Starch Solution--Mill 5 g of arrow-root starch and 5 to 10 mg of mercuric iodide (Hgl2) (Warning--See Note 6.) with 3 to 5 mL of water. Add the suspension to 2 L of boiling water and boil for 5 to 10 min. Allow to cool and decant the clear supernatant liquid into glass stoppered bottles.

7. Reagents

7.1 Purity of Reagents--Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents shall conform to the specifications of the American Chemical Society where such specifications are available: Other grades may be used, providing it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination. 7.2 Purity of Water--Unless otherwise indicated references to water shall be understood to mean distilled water, or water of equivalent purity. 7.3 Preparation and Standardization: 7.3.1 Bromide-Bromate Standard Solution (0.05 N)-Dissolve 5.1 g of potassium bromide (KBr) and 1.4 g potassium bromate (KBrO3) in water and dilute to 1 L. Standardize to four significant figures as follows: Place 50 mL of glacial acetic acid (Warning--See Note 4.) and 1 mL of concentrated hydrochloric acid (HCI, sp gr 1.19) (Warning--See Note 5.) in a 500-mL iodine number flask. Chill the solution in an ice bath for approximately 10 rain and with constant swirling of the flask, add from a 50-mL buret 40 to 45 mL ofbromide-bromate solution, estimated to the nearest 0.01 mL, at a rate such that the addition takes between 90 and 120 s. Stopper the flask immediately, shake the contents, place it again in the ice bath, and add 5 mL of potassium iodide (KI) solution in the lip of the flask. After 5 rain remove the flask from the ice bath and allow the KI solution to flow into the flask by slowly removing the stopper. Shake vigorously, add 100 mL of water in such a manner as to rinse the stopper, lip, and walls of the flask, and titrate promptly with the standard sodium thiosulfate (Na2S203) solution. Near the end of the titration add 1 mL of starch indicator solution and titrate slowly to the disappearance of the blue color. Calculate the normality of the bromide-bromate solution as follows:

NOTE 6: Warnlng--Poison. May be fatal if swallowed. See Annex A3.3.

7.3.5 Sulfuric Acid (l+5)--Carefully add 1 volume of concentrated sulfuric acid (H2SO4, sp gr 1.84) to 5 volumes of water and thoroughly mix. (Warning--See Note 7.) NOTE 7: Warning--Poison. Corrosive. Strong Oxidizer. Contact with organic material may cause fire. May be fatal if swallowed.

7.3.6 Titration Solvent--Prepare 1 L of titration solvent by mixing the following volumes of materials: 714 mL of glacial acetic acid, 134 mL of l,l,l-trichloroethane, 134 mL of methanol, and 18 mL of H2SO4 (1 +5). 7.4 Solvents: 7.4.1 Acetic Acid, glacial. (Warning--See Note 4.) 7.4.2 Methanol (Warning--See Note 8.) NOTE 8: WarningmFlammable. Vapor harmful. May be fatal if swallowed. Causes severe burns. Harmful if inhaled. See Annex A3.4.

7.4.3 1,1,1-Trichloroethane (Warning--See Note 9.) NOTE 9: WarninguHarmful if inhaled. High concentrations may cause unconciousness or death. Contact may cause skin irritation and dermatitis. See Annex 3.5.

8. Procedure

8.1 Switch on the titrimeter and allow the electrical circuits to stabilize according to the manufacturer's instructions. 8.2 Cool the titration vessel to 0 to 5"C (32 to 41°F) by circulating a suitable coolant through the jacketed titration vessel. 8.3 Introduce 110 mL of titration solvent into the titration vessel and pipet in a quantity of sample as indicated in Table 1 (Note 10). Switch on the stirrer and adjust to a rapid stirring rate, but avoid any tendency for air bubbles to be drawn down into the solution. Allow the contents to cool to 0 to 5°C (32 to 41°F) and maintain at this temperature throughout the titration. (WarningnSee Note I l.)

N l = A2N2/A ]

where: N] -- normality of the bromide-bromate solution, A~ -- millilitres of the bromide-bromate solution, N2 = normality of the Na2S203 solution, and A2 = millilitres of the Na2S203 solution required for titration of the bromide-bromate solution. 4 Reagent Chemicals, American Chemical Society Specifications, American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed by the American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville, MD.

TABLE 1 Sample Size Bromine Index 100 to 500 Over 500 to 1000

414

Sample Size,g 10 to 8 8 to 4

( ~ D 2710 - (~ 2 9 9 NOTE 10--Frequently the order of magnitude of the bromine index of a sample is unknown. In this case, a trial test is recommended using an 8 to 10g sample in order to obtain the approximate magnitude of the bromine index. This exploratory test should be followed with another determination using the appropriate sample size as indicated in Table 1. The sample mass can be determined by obtaining the density of the sample and calculating the mass of a measured volume. NOTE 11: WarningmHydrocarbon samples, particularly those boiling below 205°C (400"F) are flammable. See A3.3. 8.4 Adjust the potentiometer until the electric eye is half-open. If flickering of the eye is observed at this setting readjust to a more closed position. 8.5 Add the bromide-bromate solution in small increments from the 10-mL buret until the eye begins to open. Continue adding the reagent, 0.10 mL at a time, until the eye remains fully open for a period of not less than 30 s. This is the end point. NOTE 12--Certain electric eyes do not quite fully open, but there is generally no difficulty in detecting the end point in spite of this. NOTE 13--With commercial titrimeters, a sudden change in potential is indicated on the meter or dial of the instrument as the end point is approached. When this change persists for 30 s it marks the end point of the titration. With each instrument, the manufacturer's instructions should be followed to achieve the sensitivity in the platinum electrode circuit specified in 6.1. 8.6 Blanks--Make duplicate blank titrations on each batch of titration solvent and reagents. Less than 0.10 mL of bromide-bromate solution should be required. 9. Calculation

B

= millilitres of bromide-bromate solution required for titration of the blank, N = normality of bromide-bromate solution, and W -- grams of sample.

10. Precision and Bias 10.1 Precision: 10.1.1 The precision of this test method as obtained by statistical examination of interlaboratory test results is as follows: 10.l.l.1 Repeatability--The difference between successive test results obtained by the same operator with the same apparatus under constant operating conditions on identical test material would, in the long run, in the normal and correct operation of the test method, exceed 14 only in one case in twenty. 10.l.l.2 Reproducibility--The difference between two single and independent results, obtained by different operatots, working in different laboratories on identical test material, would in the long run, in the normal and correct operation of the test method, exceed I 18 only in one case in twenty. 10.2 Bias: 10.2.1 The procedure in this test method has no bias because the value of bromine index can be defined only in terms of a test method. NOTE 14--The precision for this test method was not obtained in accordance with RR:D02-1007: The interlaboratory test results are given in A2. l l . Keywords

9.1 Calculate the bromine index as follows:

11.1 bromide-bromate solution; bromine index; electrometric titration; hydrocarbons; petroleum

Bromine index = [(A - B)N x 7990]/W where: A = millilitres of bromide-bromate solution required for titration of the sample,

s Annual Book ofA S T M Standards, Vol 05.03.

415

~l~ D 2710 -

(~ 299

ANNEXES (Mandatory Information) AI. APPARATUS available than those for the electric eye circuit. It has been demonstrated that the results obtained are comparable. Connection to the platinum wire electrode pair is made at the points of the diagram as illustrated.

A I.I The wiring diagram of a recommended electrometric (electric eye) titration apparatus is shown in Fig. A 1.1. An alternative transistorized circuit is shown in Fig. AI.2. The components for this circuit are now more readily

R9

ELECTRODESRI~ !

T

t

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y

oL

TeN C2

R7 R l m l 0 0 k9 R2--1 kf~ R3--1 k0 R4--40 kfl R5---470 kQ R6---50 kQ R7~10 kQ R8--470 kfl R9~15 kg R6 Variable wlrewound 5 W R9 Wirewound ±5 • 5 W All other resistors ±20 ~ 1 W FIG. A1.1

Cl---0.1 pF C2m16 I~F VIDECC 83 or 12AX7 V2DEM 81 or 6 DA5 (GE) V3--5Y3 or nearest equivalent T--Transformer 240-0-240 V, 40 mA 6.3 V 2 A, 5 V 2 A FDFuse, 1 A

Circuit of Electrometdc Titrimeter

416

I1~ O 2 7 1 0 - (~) 2 9 9

RI9 R9

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LED Type • Vl Rill

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p

LED RL21

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l

(ll¢lrod* Sockets (2ram)

....

R1~10 R2--560 fl R3---100 kfl R4~1 k9 R5--100 kfl R6---6.8 kfl R7~3.3 kfl R8---2.7 kfl R9---330 kQ R10--4.7 k9 Rll--4.7 k9

VRI--10 kfl V R 2 ~ 7 0 fl 10-turn V R ~ 1 0 kQ VR4~I k9

R12a180 kfl; 100 kfl if 100-pA meter used R13--10 kfl R14--560 Q R15--180 R16--1 MQ R17~10 kfl R18--6.8 kfl R19--1.2 kfl R20--1.2 kfl All resistors 0.5-W thin film (Cermet) R10 may be varied to suit measurement conditions C1--0.2 pF C2~10 pF C3--0.1 pF C4--0.1 pF

I--AD 741K, Analog Devices II--SN 741P, Texas Instruments D1--15920 or 1N4001 D2--LED, Type A D3--LED, RL21 or Monsanto 5026 V1--BC 182LB or 2N3302, 2N4953, 2N5376, 2N5377, SK3122 V2--BC 212LB or 2N2907, 2N3251, 2N3486, 2N3505, 2N3672, 2N3673, 2N4143, 2N4228, SK3114, 3144 F--Fuse, 100 to 125 I~, M--Meter, 50 or 100 S--Swltch, SPST L--Pilot light, NE 51 Power Supply--Farnell 15/15/100 P or Acopien Model D15.15A, Case EL-10

FIG. A1.2 Alternative Transistorized Circuit of Electrometdc Titrimeter

417

~

V 2710 - (~) 299

A2. RESULTS OF BROMINE INDEX COOPERATIVE PROGRAM TABLE A2.1 Sample Lab. 1

2

3

4

5

6

7

8

1091 1 2 avg 1 2 avg 1 2 avg 1 2 avg 1 2 avg 1 2 avg 1 2 avg 1 2 avg

1064 1064

1093

116 120 1064

1081 1102

118

1092

1106

142

(1120)

1044

1055

1062

1276e 1078

388

549

113

393

570

142 123

381 360 366

365 385

718 719

(416) 389 373

395 390

573 566

142 141

398

535

114

544 416 ...

388 388

549 548

113 113

1277 1274

403

(582)

116

471 544 544

397 399

532 537

113 115

1063 1061

359

688

121

447 467 474

409 397

582 ...

116 116

1055 1055

392

589

363 443 450

375 449 451

719 a 584

Poo;ed

447 447

349 368

688 688

124 116

1039 1049

576

117

1095

391 392

573 A 604 A

147 136

1120 ...

1094

576 576

115 119

1097 1114

~averege

Bromine Index

1092

447 620 621

450 395

621 a 438

Repeatability Degrees of freedom ~r,, standard deviation r, repeatability

13 5.5 16.8

15 2.2 6.6

Degrees of freedom ~rr, standard deviation R, reproducibility

6 28.5 99

7 12.1 40

11 1.8 5.6

15 6.1 18.6

13 3.8 11.6

31 5 14

7 26.3 88

6 60.3 208

32 41 118

ReproOuc=bility 6 49.5 171

A Excluded from repeatability calculations. a Excluded from reproducibility calculations.

A3. PRECAUTIONARY STATEMENTS A3.1 Acetic Acid (Glacial) A3.1.1 Do not ~et in eyes, on skin, on clothing. A3.1.2 Do not breathe vapor, spray, or mist. A3.1.3 Dilute by addition of acid to water. A3.1.4 Keep away from heat and open flame. A3.1.5 Keep in tightly closed container in approved acid storage cabinet. A3.1.6 Keep cool. A3.1.7 Loosen closure carefully when opening. A3.1.8 Use with adequate ventilation. A3.1.9 Keep container closed when not in use. A3.1.10 Use protective clothing and goggles when handling. A3.1.11 Wash thoroughly after handling.

A3.2.4 Keep in tightly closed container in approved acid storage cabinet. A3.2.5 Keep cool. A3.2.6 Loosen closure carefully when opening. A3.2.7 Use with adequate ventilation. A3.2.8 Keep container closed when not in use. A3.2.9 Use protective clothing and goggles when handling. A3.2.10 Wash thoroughly after handling.

A3.3 Mercuric Iodide A3.3.1 Harmful if inhaled. A3.3.2 Do not get in eyes, on skin. A3.3.3 Do not ingest or breathe dust. A3.3.4 Use protective gloves and goggles when handling. A3.3.5 Keep container closed when not in use. A3.3.6 Wash thoroughly after handling. A3.3.7 Do not get in eyes, on skin, on clothing. A3.3.8 Do not breathe vapor, spray or mist. A3.3.9 Dilute by addition of acid to water.

A3.2 Hydrochloric Acid (Concentrated) A3.2.1 Do not get in eyes, on skin, on clothing. A3.2.2 Do not breathe vapor, spray, or mist. A3.2.3 Dilute by addition of acid to water. 418

(~

O 2710 - (~) 299

A3.3.10 Keep in tightly-closed container in approved acid storage cabinet. A3.3.11 Keep cool. A3.3.12 Loosen closure carefully when opening. A3.3.13 Use with adequate ventilation. A3.3.14 Do not allow water to get into container because of violent reaction. A3.3.15 Keep container closed when not in use. A3.3.16 Use protective clothing and goggles when handling. A3.3.17 Wash thoroughly after handling.

A3.5 1,1,1-Trichloroethane A3.5.1 Avoid prolonged or repeated breathing of vapor and spray mist. A3.5.2 Use only with adequate ventilation. A3.5.3 Eye irritation and dizziness are indications of overexposure. A3.5.4 Do not take internally. Swallowing may cause injury, illness or death. A3.5.5 Avoid prolonged or repeated contact with skin. A3.5.6 Do not get in eyes.

A3.4 Methanol A3.4.1 Keep away from heat, sparks and open flame. A3.4.2 Keep container closed. A3.4.3 Avoid contact with eyes and skin. A3.4.4 Avoid breathing of vapor or spray mist. A3.4.5 Use with adequate ventilation. A3.4.6 Do not take internally.

A3.6 Flammable Liquid A3.6.1 Keep away from heat, sparks, and open flame. A3.6.2 Keep container closed. A3.6.3 Use only with adequate ventilation. A3.6.4 Avoid prolonged breathing of vapor or spray mist. A3.6.5 Avoid prolonged or repeated contact with skin.

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and ff not revised, either reepproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103.

419

(~~l~) Designation: D 2712 - 91

An American National Standard

Standard Test Method for Hydrocarbon Traces in Propylene Concentrates By Gas Chromatography 1 This standard is issued under the fixed designation D 2712; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number m parentheses indicates the year of last reapproval. A superscript epsilon (~) indicates an editorial change since the last revision or reapproval.

1. Scope 1.1 This test method covers the determination of 5 to 500 ppm each of ethylene, total butylenes, acetylene, methyl acetylene, propadiene, and butadiene in propylene concentrates. 1.2 The values stated in SI units are to be regarded as standard. The values stated in inch-pound units are for information only. 1.3 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety practices and to determine the applicability of regulatory limitations prior to use. 2. Referenced Documents

2.1 ASTM Standards." E 260 Practice for Packed Column Gas Chromatography2 F 307 Practice for Sampling Pressurized Gas for Gas Analysis3 3. Summary of Test Method 3.1 A relatively large volume of sample is charged to a gas partition chromatography apparatus which has a column that will separate the trace hydrocarbon constituents from the major components. Any column or combination of columns may be used provided they have the necessary resolution and the detecting system has sufficient sensitivity. Several columns that have been found satisfactory are given in 5.1. 3.2 Calculation is performed by calculating the concentration of the trace compound from its area relative to the area of a standard compound of known concentration.

of 20 ppm or more so that the resolution ratio, A/B, will not be less than 0.4, where A is the depth of the valley on either side of peak B and B is the height above the baseline of the smaller of any two adjacent peaks (see Fig. 1). For compounds present in concentrations of less than 20 ppm the ratio A/B may be less than 0.4. In the case where the small-component peak is adjacent to a large one, it may be necessary to construct the baseline of the small peak tangent to the curve as shown in Fig. 2. Butylenes need not be resolved from each other. Columns found to be acceptable together with operating conditions used are shown in Table I. Table 2 shows typical retention times. 5.1.1 Columns may be constructed of 3.2-ram (l/s-in.), 6.4-mm (V4-in.), or capillary tubing and usually need to be a minimum of 6 m (20 It) in length. They usually have 20 to 40 g of liquid substrate to 100 g of solid support. If packed columns are used, the liquid may be placed on the solid support by any suitable method, provided the column has the desired resolution and sensitivity. NOTE l--Separation of all the desired c o m p o u n d s on a single c o l u m n has been found by cooperators to be very difficult. Most laboratories have found it necessary to use two or more columns. Typical instructions for preparing such c o l u m n s may be found in Recommended Practice E 260.

5.2 Gas Chromatograph--Any gas chromatography apparatus may be used provided the system has sufficient sensitivity to detect the trace compounds of interest. For calculation techniques utilizing a recorder, the signal for 20 ppm concentration shall be at least 5 chart divisions above the noise level on a 0 to 100 scale chart. The noise level must be restricted to a maximum of 2 chart divisions. When electronic integration is employed, the signal for 20-ppm concentration must be at least twice the noise level.

4. Significance and Use 4.1 The trace hydrocarbon compounds listed in Table 2 may have an effect in the commercial use of propylene concentrates, and information on their concentration is frequently necessary. 5. Apparatus 5.1 Columns--Any column may be used provided it will resolve the trace compound peaks present in concentrations i This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibdity of Subcommittee D02.D on Hydrocarbons for Chemical and Special Use. Current edition approved March 15, 1991. Published June 1991. Originally published as D 2712 - 68 T. Last previous edition D 2712 - 85. 2 Annual Book of ASTM Standards, Vol 14.01. 3 Annual Book of ASTM Standards, Vol 10.05.

FIG. 1

420

Illustration of

A/B Ratio

~

D 2712

ratus. Pressure sampling devices may be used to inject a small amount of the liquid directly into the carder gas. Introduction may be by means of a gas valve to charge the vaporized liquid.

FIG. 2

6. Reagents and Materials 6.1 Hydrocarbons, for peak identification, including propylene, ethylene, ethane, acetylene, methyl acetylene, propadiene, propane, 1,3-butadiene, isobutylen¢, l-butene, cis and trans 2-butene, iso- and normal butane, and cyclopropane. (Warning--See Note 3.) Mixtures of these hydrocarbons may be used for calibration provided there is no uncertainty as to the identity of the desired compound. 6.2 Propane or Propylene, for synthetic base stock containing less than 2 ppm by weight of acetylene or l',3butadiene. (Warning--See Note 3.) 6.3 Calibration Compounds--Acetylene and 1,3-butadiene 99 % minimum purity. (Warning--See Note 3.) 6.4 Carrier Gases--Helium or Nitrogen. (Warning-See Note 4.)

Illustration of A/B Ratio for Small-Component Peak

NOTE 2--A flame ionization detector is preferred. When using with relatively volatile liquid phases, such as HMPA, an additional 0.3 l-m (l-ft) section of column containing uncoated solid support will aid in reducing noise.

5.3 Sample Introduction--Means shall be provided for introducing a measured quantity of sample into the appaTABLE 1

Column

I

I

2

Liquid Weight, ~ Solid Mesh Treatment Length, ft Inside diameter, in.

I

3

I

4

I

5

I

s

I

7

I

8

Mixed 20 TCEP

Series

SenesA

Column:

Temperature: Inlet, °C Detector, °C Column, °C Sample: Injection Gas, cm3 Split Carrier: Gas cm3/min Detector: Type Voltage Recorder: Range, mV in./h Measurement

1

Typical Column Conditions

IDMS

Squa

DMS

ODPN

U C O N DMS

None

33 Chrom 60 to 80 none 0 4.19

22 Chrorn 60 to 80 none 30 0.13

U Chrom 100 U 22 0.085

15 Chrom 80 to100 U 20 0,085

15 Chrorn U U 8 0,085

15 Chrom 60 to 80 U 16 0.085

I

9

1101

Mixed 80 MEEE

Series

O O P N nC16

HMPA

8 DIDP

None

DMS

Squa

SiGel U U 3.5 0.18

80 % SE-30 25 Chrom 30 toS0 AW 50 0,19

25 Chrom 30 to 60 AW 50 0.19

20 Chrom 60 to 80 AW 20 0.085

30 Chrom 60 to 80 AW 20 0,085

20 Chrom 60 to 80 none 25 0.085

SiGel 40 to 60 FeCI 15 0.19

33 Chrom 60 to 80 none 8 0,085

20 Chrom 60 to 80 none 35 0.085

RT 150 RT

RT RT RT

RT 50 50

RT 50 50

160 175 30

70 70 70

RT RT RT

RT RT RT

RT RT RT

RT RT RT

RT RT RT

GV 0.5

GV 0.2

!GV 1

GV 0.7

Syr 3.C

Syr 1

GV 0.5

GV 5 40:1

GV 0.4

GV 0.4

GV 1

He 50

He 22

He 24

He 42

He 40

He 40

H2 17

He 60

He 30

He 30

He 52

FI

TC 8

FI

TC 12

FI

TC 70

FI

FI

FI

FI

FI

1 30 Tri

1 60 Plan

5 30 Plan

1 30 Plan

1 30 PH

1 30 PH

5 30 PH

5 30 PW/2

1 60 Tri

1 60 Tri

1 30 Tri

A Detector by-passed during major peaks. Abbreviations: AW Chrom DIDP DMS FeCI FI GV He H2 HMPA MEEE nCls

11

Acid washed =Chromosorb"P (trademark of Johns-Manville Products Corp.) Oiisodecyl phthalate 2,4-dimethyl sulfolane Ferric chloride, modified Flame ionization Gas valve Helium Hydrogen Hexamethyl phosphoramide Bis-2(methoxy ethoxy ethyl) ether Normal hexadecane

ODPN PH Plan PW/2 RT SE-30 SiGel Squa Syr TC TCEP Tri U

421

/~,/V-oxydipropionitrile Peak height Planimeter Peak height x width at ½ height Room temperature SE-30 gum rubber Silica gel Squalane Syringe Thermal conductivity 1,3-tris(2-cyano ethoxy)propane Triangulation Unknown

I{~ D 2712 TABLE 2 Column

1

Acetylene 1,3-Butadiene Isobutene 1-Butene

10.1 39.4 33.3

trans-2-Butene cis-2-Butene

42.1 46.9 22.8 8.1 24.2 34.3 A 20.6

Cyclopropane Ethylene Methyl acetylene Neopentane Propadiene

2

3

T y p i c a l R e t e n t i o n T i m e , Min

4

5

6

7

8

10

11

2.2

22.3 20.8 J 11,0"~ [ 1 1.4 J

...

..,

i513

6.5 ...

17.4 10.9

...

8.0 35.1 29.7

13.1 15.1 8,3

12.9 14.8 ...

316

~17

28:0

i6:4

...

21.1

88

i;:o

'"

i~:8

. . . . . . 2419 ,,.

...

{8.7

... ... .

.

...

.

.

}15.7

9.5

. . . . . .

11,8 14.2

. . . . . . . . . . . .

.

.

.

... 2i5:1 . . . . . . . . . . . . . . . ... 10.2

.

.

.

.

18,1 20.5

.

7.2

12.0

5,1

...

23

i8:3

5.8 ...

iii

i i 13

i;:4

9

... ...

38.0 a 42.8

..,

A Squalane portion only. B DMS portton only.

6.5 Hydrogen. (Warning--See Note 5.) 6.6 Liquid Phase for Column--See Table 1. (Warning-See Note 6.) 6.7 Solid Support--C22 firebrick or diatomaceous earth, usually 40 to 60 or 60 to 80 mesh. 6.8 Stainless Steel Sample Cylinder, 300 to 500-cm 3 capacity, capable of withstanding a minimum of 1723 kPa gage (250 psig). 6.9 Silicone Rubber Septum, with suitable fittings for attachment to sample cylinder. 6.10 Gas Syringe, 10-cm 3. 6.11 Vacuum Pump, capable of evacuating sample cylinder to less than 2 mm Hg absolute pressure. 6.12 Aluminum or Stainless Steel Tubing, 0.61 m (2 ft), 3.2 m m (I/8 in.), or 1.6 mm (IA6 in.), outside diameter with fittings on one end to connect to butadiene cylinder and the other end modified so as to have an opening with an inside diameter of about 0.5 mm larger than the outside diameter of the gas syringe needle. NOTE 3--Warning--Liquified petroleum gas under pressure and flammable. NOTE 4--Warning--Compressed gas under pressure. NOTE 5--Warning--Compressed gas under pressure and flammable. NOTE 6--Warning--Hexamethylphosphoramide is a potential carcinogen.

7. Calibration 7.1 Select the conditions of column temperature and carrier gas flow that will give the prescribed separation. 7.2 Determine the retention time for each compound by injecting small amounts of the compound either separately or in a mixture using the same method of charging as is used for the sample. 8. Synthetic Standard 8.1 Connect the silicone septum to a valve of the stainless steel sample cylinder in such a manner that the volume between the septum and the valve is less than 1% of the total volume of the cylinder. By means of suitable fittings connect the other valve of the cylinder to a vacuum pump and evacuate the cylinder and space between the cylinder valve and septum. Close the valves, disconnect the cylinder from the vacuum pump, and weigh the empty cylinder on a suitable platform balance to the nearest 1 g. 8.2 Connect the tubing to the 1,3-butadiene cylinder and crack the valve on this cylinder so that there is a constant flow of vapors from the end of the tubing which must be at 422

TABLE

3

Molecular

Weight and Specific Gravity

Compound

Molecular Weight

Specd¢ Gravity, 60/60

Propylene Propane

42.08 44,09

0.5220 0.5077

room temperature. Insert the syringe into the end of the tubing and slowly withdraw 5 cm 3 of the butadiene vapors. Flush the syringe three times with vapors and inject exactly 5 cm 3 of the vapor through the septum into the evacuated cylinder. Close the valve between the cylinder and the septum. Inject 5 cm 3 of acetylene to the evacuated cylinder in the same manner. 8.3 Fill another cylinder of the same size with propane or propylene base stock. Establish outage in the base stock cylinder by removing 25 % of the liquid contents. Place the cylinder containing the blend stock in a vertical position so that the bottom valve is above the top of the cylinder containing the butadiene. If the cylinder containing the base stock is equipped with a dip pipe be sure that this valve is at the top. Connect the bottom valve of the base stock cylinder to the other cylinder by means of suitable tubing capable of withstanding 1723 kPa (250 psi) pressure. Flush the connecting line with base stock before tightening connections to the evacuated cylinder. Cool the evacuated cylinder to a temperature of I l to 17*C (20 to 30*F) below that of the base stock. Open the valves between the two cylinders and allow the base stock to flow into the cylinder containing the butadiene. Close the valves, disconnect, and allow the cylinder to warm to room temperature. Reweigh on the platform balance and determine the total weight of base stock containing the butadiene and acetylene. 8.4 Calculate the ppm by weight of acetylene and butadiene in the standards as follows: cm 3 compound x 273 Weight, ppm = 273 + T mol wt (I) Z × - × - - x 106 22 410 total wt where: T = room temperature, *C, Z = 1.026 correction factor for butadiene, ideal volume/absolute volume, and 1.0 correction factor for acetylene, ideal volume/absolute volume, and

~) mol wt

=

D 2712 valve under static conditions of flow. With the exit of the chromatograph valve closed open the valve on the cylinder. Slowly open the exit from the chromatograph valve so that liquid flows through the connecting line and valve. Close the exits so that the liquid sample is trapped in the valve. Perform the necessary operations to introduce the liquid sample into the chromatograph column. 9.5.2 Vaporized Sample--Assemble the apparatus similar to that illustrated in Fig. 3. Disconnect the 1700-cm 3 cylinder at E and evacuate. Close valve B and open valves C and D, allowing the liquid sample to flow into the small cylinder. Slowly open valve B and allow the sample to flow through until a steady slow stream of liquid emerges from B. Close valves B, C, and D in that order, trapping a portion of the liquid sample in the pipe cylinder (Note 8). Attach the evacuated cylinder (1700-cm 3 volume) at E. Open valve A and then valve B. The liquid will expand, filling the larger cylinder and give a gage pressure of approximately 55 kPa (8 psi) for propylene concentrates. Close valve A and disconnect at E. NOTE 7--To avoid possible rupture of the liquid-filledpipe cylinder, the sample cylinder and its contents should be at room temperature prior to samplingand the liquid should be allowedto remain in the pipe cylinder for only a minimum amount of time. 9.5.2.1 Connect the cylinder containing the vaporized sample to the chromatograph gas valve. Evacuate the sample loop and the lines up to the sample cylinder. Close the valve to the vacuum source and allow the sample loop to fill with sample up to atmospheric pressure. Repeat the evacuation and filling of the sample loop with vaporized sample. Turn

54.1 for butadiene, and 26.0 for acetylene.

9. Sampling 9.1 This section is to be followed on all samples including unknown samples and the synthetic standards. 9.2 Samples should be supplied to the laboratory in high-pressure sample cylinders, obtained using the procedures described in Practice F 307 or similar methods. 9.3 Place the cylinder in a horizontal position in a safe location such as a hood. Check to see that the container is at least one-half full by slightly opening the valve. If liquid is emitted (a white cloud of vapors) the container is at least one-half full. Do not analyze any samples or use any synthetic standard if the liquid in the container is less than this amount. 9.4 Place the cylinder in a vertical position and repressure to 1723 kPa gage (250 psig) with the chromatographic carrier gas through the valve at the top of the cylinder, ensuring that no air enters during the operation. 9.5 Use either of the following two procedures for obtaining a sample from the container: 9.5.1 Using a Liquid Valve--Connect the cylinder to the liquid valve on the chromatograph using a minimum length of connecting tubing, so that sample is withdrawn from the bottom of the cylinder and a liquid sample is obtained. The liquid valve on the chromatograph must be designed in such a manner that full sample pressure can be maintained through the valve without leaking and that means are provided for trapping a liquid sample in the chromatograph

Stainless Steel Cylinder 1700 cc volume Pressure-Vacuum G

a

u

~ A ¢ B

2 RF2

Whitey Valves 316 SS

~---

i-.i/8" ig x 1/4" O.D. SS tubing connected with Swagelok Fittings

/

Clamp to hold Cylinder

--~

Ring Stand

Standard 1/8" SS pipe 15" ig

Cylinder Containing Liquid Sample (LPG) C

D l

1/4" OD SS tubing connected to valves with 1/4" Swagelok to 1/8" pipe fittings FIG. 3 Sampling and ExpansionCylinder Arrangement 423

D 2712 the valve so that the vaporized sample is displaced with carder gas into the chromatograph.

TABLE 4

10. Procedure 10.1 Using the same conditions as were used for identification of peaks, record the peaks of all compounds of interest at a maximum sensitivity in a manner to allow measurement of the area of each hydrocarbon trace component. 10.2 Charge the synthetic standard in the same manner as the sample and under the same conditions. Make duplicate runs of the standard.

Relative Response Factors

Compound

Response Factor, g/relative area

Acetylene Butadiene Isobutylene Ethylene Methyl acetylene Propadiene Cyclopropane

62 68 69 59 57 62 63

TABLE 5

Precision of Method A Amount Present,

Compound

11. Calculation 11.I Measure the area of each hydrocarbon trace peak and the area of the butadiene peak in the standard. Use acetylene in the standard as comparison for ethylene and acetylene in the sample. Use butadiene in the standard as comparison for the other trace compounds in the sample. 11.2 Flame Ionization Detector--Assume that the area is proportional to the weight concentration of each compound. Trace compound, ppm = (AJAo) x S (2) where: As = area due to the trace compound, A o -- average area of acetylene or butadiene in the standard, and S --concentration of acetylene or butadiene, ppm, in the standard. NOTE 8--If the standard is prepared in a base stock different from the sample, an additional correction must be made to compensate for the fact that identical weights are not charged when charging at constant gas volume or constant liquid volume. When charging at constant gas volume, multiply the results in 10.2 or 10.3 by the factor: mol wt standard/tool wt sample When charging at constant liquid volume, multiply by: (sp gr 60/60 standard)/(sp gr 60/60 sample)

(3)

11.3 Thermal Conductivity Detector~Using the relative response factors in Table 4, correct the areas for difference in response.

Acetylene B Butadiene A Butenes, total c Ethylene a Methyl acetyleneD Propadiene°

Concentration, ppm

Repeatability

Reproducibility

15 to 30 101 29 75 346

11 6 22 7 5

53 26 53 39 30

37 82 to 220 21 ~ 60 [ 44 to 53

11 "1 4.3[ 14 8

64 42 23 52

A Subject to revision as further cooperative work is completed. a Based on results from 6 laboratories on 3 samples. c Based on results from 8 laboratories on 1 sample. O Based on results from 8 laboratories on 2 samples.

12. Precision and Bias 12.1 The criteria shown in Table 5 should be used for judging the acceptability of results (95 % probability). The precision statements are based on the results from 7 laboratories analyzing 2 samples and should be considered tentative pending further study and evaluation. 12.1.1 RepeatabilitymDuplicate results by the same operator should be considered suspect if they differ by more than the amounts shown in Table 5 for repeatability as percent of the average amount present. 12.1.2 ReproducibilitymThe results submitted by two laboratories should be considered suspect if they differ by more than the amount shown in Table 5 for reproducibility as percent of the average amount present. 12.1.3 Bias~Since there is no accepted reference material suitable for determining the bias for the procedure in Test Method D 2712 for measuring hydrocarbon traces, no statement on bias is being made.

Trace compounds, ppm = [(As x RF)/(A o × 68)] x S where: As = area due to the trace compound, Ao = area of acetylene or butadiene in the standard, R F = response factor of acetylene or butadiene, and S = concentration of acetylene or butadiene, ppm, in the 13. Keywords standard. 13.1 gas chromatography; hydrocarbon impurities; pro(See Note 8.) pylene

424

~

D 2712

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103.

425

Designation: D 2784 - 92

An American National Standard

Standard Test Method for Sulfur in Liquefied Petroleum Gases (Oxy-Hydrogen Burner or Lamp) 1 This standard is issued under the fixed designation D 2784; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (d indicates an editorial change since the last revision or reapproval.

1. Scope 1.1 This test method covers the determination of total sulfur in liquified petroleum gases containing more than 1 ktg/g. Specimens should not contain more than 100 ~tg/g of halogens. 1.2 To attain the quantitative detectability that the method is capable of, stringent techniques must be employed and all possible sources of sulfur contamination must be eliminated. In particular, cleaning agents, such as common household detergents which contain sulfates, should be avoided. 1.3 The values given in acceptable metric units are to be regarded as the standard. 1.4 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate sa~,ty and health practices and determine the applicability of regulatory limitations prior to use.

2. Referenced Documents

2.1 ASTM Standards: D 156 Test Method for Saybolt Color of Petroleum Products (Saybolt Chromometer Method)2 D 1265 Practice for Sampling Liquefied Petroleum (LP) Gases2 D 1266 Test Method for Sulfur in Petroleum Products (Lamp Method)2 D 1657 Test Method for Density or Relative Density of Light Hydrocarbons by Pressure Thermohydrometer2 E l l Specification for Wire-Cloth Sieves for Testing Purposes 3 2.2 Institute of Petroleum Standard. ~ IP 181 Sampling Petroleum Gases, Including Liquefied Petroleum Gases 3. Summary of Test Method 3.1 The sample is burned in an oxy-hydrogen burner, or in a lamp in a closed system in a carbon dioxide-oxygen atmosphere. The latter is not recommended for trace quani This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.03 on Elemental Analysis. Current edition approved March 15, 1992. Published May 1992. Originally published as D 2784 - 69 T. Last previous edition D 2784 - 89. 2 Annual Book oJASTM Standards, Vol 05.01. Annual Book of ASTM Standards, Vol 14.02. 4 Available from American National Standards Institute, I 1 W. 42nd St., 13th Floor, New York, NY 10036.

tities of sulfur due to the inordinately long combustion times needed. The oxides of sulfur are absorbed and oxidized to sulfuric acid in a hydrogen peroxide solution. The sulfate ions are then determined by either of the following finishes: 3.1.1 Barium Perchlorate TitrationmThe sulfate is titrated with barium perchlorate using a thorin-methylene blue mixed indicator. 3.1.2 TurbidimetricwThe sulfate is precipitated as barium sulfate and the turbidity of a suspension of the precipitate is measured with a photometer.

4. Significance and Use 4.1 It is important to have the sulfur content of liquefied petroleum gases at low enough concentration to meet government regulations. The presence of sulfur can result in corrosion of metal surfaces. Sulfur can be poisonous to catalysts in subsequent processing. 5. Apparatus 5.10xy-Hydrogen Combustion AssemblymThe two types listed below are recommended. Any combustion apparatus giving equivalent results, however, is satisfactory. 5.1.1 Wickbold.Type Combustion Apparatus, 5 as shown in Fig. 1. 5.1.2 Modified Beckman Burner-Type Apparatus, 6 as shown in Fig. 2. Each of the above types of apparatus shall consist of three parts: atomizer-burner, combustion chamber, and absorber with spray trap. A blowout safety port in the combustion chamber is desirable. The remainder of the apparatus shall consist of a suitable support stand with the necessary needle valves and flow meters for precise control of oxygen, hydrogen, and vacuum. 5.1.3 Safety ShieldwA transparent shield shall be used to protect the operator in the event an explosive mixture is formed in the combustion chamber. 5.2 Apparatus for Lamp Combustion: 5.2.1 Absorbers, Chimneys, and Spray Traps, as required are described in detail in Annex A3 of Test Method D 1266. 5.2.2 Manifold System, consisting of a vacuum manifold with regulating device, valves, etc. (Fig. 2 of Test Method D 1266) and a dual manifold (burner and chimney) supplying a gas mixture of approximately 70 % carbon dioxide (CO2) and 30 % oxygen (O2) at regulated pressures. The gas 5 Available from Koehler Instrument Co., Inc., 1595 Sycamore Ave., Bohemia, NY 11716, with an all-stainless steel burner, or from Atlas Instrument Co., 8902 E. 1lth St., Tulsa, OK. For the latter, Hoke No. 993 combination flow meter-valve assemblies should be substituted for those supplied. 6 Available from Scientific Glassblowin8 Co., P.O. Box 18353, Houston, TX 77023.

426

~'~ O 2784 Voc

Woter

Tn

A=t

Committee on Analytical Reagents of the American Chemical Society, where such specifications are available, s Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination. 6.2 Purity of Water--Unless otherwise indicated, references to water shall be understood to mean reagent water as defined by Types II or III of Specification D 1193. Water conforming to the following specification is required. Sulfate-free deionized water prepared by percolation of water through a column of mixed anion and cation exchange resins.

Out

33

~e

NOTE l - - A means for determining when to replace the exchange resins should be provided. Use of a simple electrical conductivity meter has been found satisfactory for this purpose.

w

®

6.3 Standard Sulfate Solution (1 mL = 100 ~tg S)--Dilute 6.24 ± 0.01 mL of 1 N sulfuric acid (H2SO4) with water to exactly 1 L. Check the dilution by titration against standard NaOH solution of about the same normality and adjust the concentration, if necessary, so that each millilitre of this solution is equivalent to 100 ~tg of sulfur. 6.4 Hydrogen (Warning--See Note 2), Carbon Dioxide (Warning--See Note 3), and Oxygen (Warning--See Note 4), meeting the requirement in Note 17.

Ht 1--Atomizer-burner 2--Sample tube 3mCombustion chamber 4--Three-way stopcock 5--Receiver 6--Spray trap FIG. 1

NOTE 2: Warning--Extremely flammable. NOTE 3: Warning--Gas may reduce oxygen available for breathing.

NOTE 4: Warning--Oxygenacceleratescombustion. 6.5 Scavenger-Rinse--Mix equal volumes of low-sulfur acetone and isopropanol. 6.6 Hydrogen Peroxide Solution (1.5 %) (l+19)--Mix 1 volume of concentrated hydrogen peroxide ( n 2 0 2 = 30 %) with 19 volumes of water. Store in a dark-colored, glassstoppered bottle.

Flow Diagram of a Typical Oxy-Hydrogen Combustion

Apparatus

mixture in the chimney manifold shall be maintained at a nearly constant pressure of I to 2 cm of water and the burner manifold at approximately 20 cm of water. A suitable arrangement is shown in Fig. 2 of Test Method D 1266 and described in A3.6 of Annex A3 of Test Method D 1266, but any other similar system giving equivalent results can be used. 5.2.3 Blast Type Gas Burner, having dimensions given in Fig. 3. 5.3 Vacuum Source, having a capacity of at least 1200 L/h. If a vacuum pump is used, it should be protected by a suitable trap. 5.4 Corrosion-Resistant Metal Cylinder, 75-mL---It shall be tested at a pressure of 600 psig (4.14 MPa gage) and shall show no leaks when filled with air or nitrogen to this pressure and submerged in water. It shall be fitted with a needle valve for connection to the burner assembly. 5.5 VariableTransformer, 0-120 V, 750-W. 5.6 Carbon Dioxide Pressure Regulator--This regulator should be of a type that eliminates the refrigeration difficulties occurring with the pressure reduction of carbon dioxide. 7

7. Sampling Test Specimens and Test Units 7.1 Obtain the test unit in a container by the method conforming to the recommendations in Practice D 1265, or IP Method 181. 7.2 Evacuate a clean, dry 75-mL cylinder and weigh to the nearest 0.05 g. Connect the container to the inverted supply cylinder and introduce 24 to 40 g of the liquefied gas, taking care that the container does not become full of liquid. To prevent this, bleed off a small amount of the liquid phase of the material after filling but before reweighing. Reweigh the cylinder to 0.05 g. Note 5--The 75-mL, corrosion-resistantmetal vessel can be cleaned as follows:Remove the needle valve. Wash the interior of the vessel and valve, first with a sulfur-freehydrocarbon, such as n-pentane, and then wash with acetone. Dry the interior of the vessel with clean compressed air and rinse it with HCI (1+10). Rinse the interior with water until the wash water is neutral to a pH test paper. Wash the vessel with acetone and allow to drain at least 10 rain. Dry the vesselwith a stream of clean, compressed air and reassemble. Note 6--If the weight of liquefied petroleum gas is maintained below 45 g in a 75-mL container, the container cannot become full of liquid at room temperature.

6. Reagents and Materials

6.1 Purity of Reagents--Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents shall conform to the specifications of the

a"Reagent Chemicals, American Chemical Society Specifications," Am. Chemical Soc., Washington, DC. For suggestions on the testing of reagents not listed by the American Chemical Society, see "Reagent Chemicals and Standards," by Joseph Rosin, D. Van Nostrand Co., Inc., New York, NY, and the "United States Pharmacopeia."

7 Victor Type SR 300, which has been found satisfactory for this application, is available from Victor Equipment Co., Controls Division, 2336 Auburn Blvd., Sacramento, CA 95821.

427

(@) D 2784 COND

QUARTZ

-- CALIBRATED

E/,~--_R// FLOW-RATE QUARTZTUB ( TUBE ~ l S SAMPLE

~ RESERVOR I

VACUUM

-

BLOW-OUT PORT

BEADS

V-5

NACE

/-2

POWERSTAT

ABSORB

OXYGEN INLET

~'~2 ~ ~11~

~-1

ORBE NT INLET

LHYDROGEN

MERCURY iNLET MANOMETER

FIG. 2 TraceSulfur ApparatusFlow Diagram 8. Procedure for Combustion of Sample 8.1 Connect the sample cylinder with stainless steel tubing to the gas expansion valve. Attach to this another section of stainless steel tubing which runs to the vicinity of the burner. Make the final connection to the burner with sulfur-free rubber tubing. Wrap the expansion valve with heating tape and connect this to a variable transformer. Insert a thermometer between the heating tape and expansion valve so that the thermometer bulb is in contact with the valve body. See Fig. 4. 8.2 Turn on the variable transformer and allow the expansion valve to reach 43"C (ll0"F). Alternatively the expansion valve may be placed in a suitable metal beaker and covered with water maintained at 110"F. 8.30xy-Hydrogen CombustionmAssemble the apparatus according to the manufacturer's directions (see also 14.1). Add to the absorber 25 mL of the hydrogen peroxide solution.

~. 85t0.5 ID 8 t I ~ i~1 ~,~ 1.00+-0.05 Circular Hole -F--~ ~'----- ~ (Plane Surface)

I 27*-2TII/~

I L))I

6o' ....

"~Do

I

NOt Fire Polish

7I~1

8or 50 OD All dimensions in mlllimetres

NOTE 7: WarninglBefore attempting subsequent operations, the operator should (1) be aware of the various hazards that can exist

FIG. 3 Blast-TypeGas Burner

Relief Valve (300 psi)

Stainless Steel i//'Sample Bomb

I I

/ J

hermometer

NeedIe---,-~'~,h,,n, ~

Valve

Stainless S Tubing and Connections

t

e

U

~ :=:d--"~'AttaChHereBUrner

~

Regulating Valve Maintained at IIO°F by Heating Tape (4-ft Length, 140W,45V) Controlled bya Variable Transformer FIG. 4 BurnerAssemblyfor LPG 428

~

D 2784

through the improper use of hydrogen as a fuel, and (2) Precaution-have the safety shield in place.

8.3.2 Light the burner and insert into the combustion chamber. If necessary, readjust gas flows. Open the bottom valve of the sample cylinder. Slowly open the expansion valve until an optimum burning rate is achieved. 8.4 Lamp Combustion~Add to the absorber 25 mL of hydrogen peroxide solution. Assemble the chimney, absorber, and spray trap and connect to the CO2-O2 and vacuum manifold. Make the necessary vacuum adjustments (see 5.1 of Test Method D 1266). Set up a control blank absorber as in 5.3 of Test Method D 1266. 8.4.1 Open the bottom valve of the sample cylinder. Slowly crack the gas expansion valve. Light the burner with an alcohol lamp, and insert the burner into the combustion chamber (chimney). 8.5 Burn a quantity of sample in accordance with Table 1. NOTE 8 - - I n burning materials with sulfur concentrations greater than 50 p.g/g, restrict sample sizes to give quantities that will not contain more than 250 I~g of sulfur for the turbidimetric finish or more than 150 ~tg for the barium pcrchlorate finish. Alternatively, aliquots of the absorber solutions which do not contain more than these maximums

can be used. NOTE 9mMinor adjustment of the gas flowrates can be necessaryto maintain those recommendedby the manufacturer. 8.6 After a sufficient quantity of sample has been burned, turn the bottom valve of the cylinder off. Allow the remaining gas in the tubing and gas expansion valve to burn itself out. Turn the heat off on the gas expansion valve. Disconnect the tubing from the sample cylinder and reweigh the sample cylinder to the nearest 0.05 g. Leave the absorber solution in the assembled lamp unit. The same absorber solution will be used for the scavenger.rinse burning. Allow the expansion valve to cool to ambient temperature. 8.7 If the oxy-hydrogen burner permits, flush the tubing and valve with l0 mL of scavenger-rinse and burn without disconnecting the tubing. Otherwise disconnect the tubing and burn in the normal liquid mode. For the lamp burning collect the dnsings in a standard lamp sulfur (see Test Method D 1266) flask. Insert a standard burner equipped with a wick into the flask and carry out the combustion as described in Section 7 of Test Method D 1266. 8.8 For the oxy-hydrogen burners, when all of the rinsings are consumed, shut down the burner as recommended by the manufacturer. 8.9 After the rinsings have been burned in the lamp, remove it, turn off the CO2-O2 supply, and turn off the vacuum pump. 8.10 For oxy-hydrogen blank determinations burn a hydrocarbon stock with a very low or nondetectable sulfur content. Make at least two of these prior to the analysis of samples with trace sulfur contents to ensure that the blanks are small and constant. Subtract from the total sulfur figures any blank so obtained. The remainder is the net micrograms TABLE 1 Sulfur Content, ppm 1 to 5 5 to 10 10 to 50

of sulfur from the sample. Likewise subtract any sulfur obtained in the lamp combustion blank from the total figure. 8.11 Disconnect the spray trap from the vacuum line and thoroughly rinse the spray trap and chimney with about 35 mL of distilled water, collecting the rinsings in the absorber. It is important that any materials clinging to these parts be transferred to the absorber to avoid low values for sulfur content. BARIUM PERCHLORATE TITRATION FINISH

9. Reagents 9. I Ion-Free WaterDDistill deionized water and store in tightly capped, high-density polyethylene bottles. 9.2 Hydrochloric Acid, Standard Alcoholic (0.1 M ) - Dilute 20 mL of aqueous 0.5 M HCI with 80 mL of isopropanol. 9.3 Inhibited Thorin.Methylene Blue Mixed Indicator SolutionmThe indicator is made up as two solutions and these mixed together in equal volumes once per week as follows: Solution A: 0.8 g thorin,9 0.29 g potassium bromate, water to make 500 mL, Solution B: 0.16 g methylene blue, 0.2 mL of 0.5 M HC1, water to make 500 mL. 9.4 Fleisher's Methyl Purple Indicator Solution. xo 9.5 Barium Perchlorate (0.005 M)DDissolve 1.95 g of barium perchlorate trihydrate ~° in 200 mL of water and add 800 mL ofisopropanol. Adjust the apparent pH to about 3.5 with perchlodc acid, using a pH meter. 9.6 PerchloricAcid, 11 70 %. 9.7 Sodium Hydroxide, Standard Solutions (0.03 M ) - Prepare by mixing 7 parts of water with 3 parts of standard 0.1 M sodium hydroxide (NaOH) solution. Concentrate 400 mL of 0.03 N NaOH solution by evaporating to 30 mL, and determine any sulfate present in accordance with Appendix A1, Turbidimetric Procedure for Sulfate of Test Method D 1266. If sulfate is found, corrections must be made for any sulfur introduced by the reagent in the alkali titration following combustion. 9.8 Methylene Blue. 10. Preparation of Working Curve

10.1 Into separate 30-mL beakers pipet each of the aliquots of the standard sulfate solution given in Table 2. See 6.3. To each aliquot add sufficient water to make 3.4 mL, 12 mL of isopropanol (total volume 15.4 mL) and 3 drops of mixed thorin-methylene blue indicator solution. Titrate as indicated below. For each sulfur level given in Table 2, titrate three of the corresponding aliquots. Plot the millilitres of titrant used versus micrograms of sulfur. Draw the best straight line through points. Check at least two points on the curved at least every l0 days.

Sample Sizes Sample Size, g

Turbidimetrlc Finish

BariumPerchlorate Finish

45 20 5

30

9 Available from Hach Chemical Co., Ames, IA. I°Available from Fleisher Chemical Co., Benjamin Franklin Station, Washington, DC 20044. i J Available from G. Frederick, Smith Chemical Co., P.O. Box 23344, Columbus, OH 43223.

10 3

429

~) O 2784 TABLE 2 Sulfur, I~g Aliquots, mL

40 0.40

TURBIDIMETRIC FINISH

Preparation of Working Curve 80 0.80

120 1.20

240 2.40

300 3.00

12. Apparatus 12.1 Photometer--Preferably a spectrophotometer having an effective band width of about 50 nm, and equipped with a blue-sensitive phototube for use at 450 nm, or alternatively a filter photometer equipped with a color filter having a maximum transmission at approximately 450 nm. 12.2 Absorption Cells, having an optical path length of 5 cm. With use the cells may become coated with a film. To remove this film, wash the cells with a detergent, using a soft brush. After cleaning, rinse thoroughly with water. NOTE 15--The procedure as written assumes an absorbance change of about 0.10 for each 100 ~tgof sulfur in 50 mL of solution measured in a 5-cm cell. Photometersemployingcellsof shorter optical paths will not give the precision of measurementstated in this method. 12.3 Scoop, capable ofdispensing 0.30 + 0.01 g of barium chloride dihydrate as specified in 13.2.

11. Procedure for Analysis of Solutions 11.1 Quantitatively transfer the absorber contents to a 500-mL Erlenmeyer flask, using ion-free water for rinsing. Add 2 drops of Fleisher's methyl purple indicator solution to this solution and titrate to a faint green end point with 0.03 M N a O H solution (Note 12). Add 1 mL more ofthe 0.03 M NaOH solution to the solution and reduce the volume to 2 to 3 mL by evaporation on a hot plate in sulfate-free environment. (Warning--see Note 11): DO NOT BOIL DRY. Cool the solution to room temperature and measure its volume in a 10-mL graduate (Note 12). Adjust the volume to 3.0 mL by adding ion-free water. NOTE 10: Warning--Do not boil.

NOTE 1l--The volume of sodium hydroxide should not exceed 2 mL. More indicates that the sulfur or halogen content is excessive or that there is a serious air leak in the apparatus. NOTE 12--For high or completely unknown sulfur contents, the concentrated absorbent can be quantitatively transferred to a 5-mL volumetric flask, adjusted to 5 mL, and aliquots used. Each aliquot is then subsequentlymade up to 3 mL as in 11.I. Continue as in 11.2. 11.2 Transfer the absorbent to a 30-mL beaker, rinse the graduate and the 500-mL boiling flask successively with two 6-mL portions of isopropanol, and add the rinses to the beaker. 11.3 Pipet 0.40 mL of the standard sulfate solution (40 ttg of sulfur) into the beaker. Add 2 drops of the thorinmethylene blue mixed indicator solution. Adjust the resultant gray-green color by adding 0.1 M HCI dropwise to the solution until the color changes to bright green. 11.4 The 2-mL buret containing standard barium perchlorate should have its tip positioned just below the surface of the solution in the beaker. The solution must be stirred by a small bar on a magnetic stirrer or with a small propeller stirrer. A white background and good white light may be helpful in obtaining a precise end point. Add the barium reagent at a steady rate of 0.1 mL in 5 (+1) s until the end point is indicated by a rapid, though slight, color change from green to a bluish gray (Note 13). Shut off the buret at the point of greatest rate of color change (Note 14). NOTE 13--It is helpful to match end point colors with solutions saved from prior standardizationtitrations performed within the last 15 min and well stirred to prevent drop-out of the colored barium sulfate precipitate. People having a low red-green color sensitivity find that using the blue light of Method D 156, sharpens the end point very considerably. NOTE 14--The end point can be checked by again adding 40 ttg of sulfur (0.4 mL standard sulfuric acid) and retitrating to the end point. 11.5 From the working curve, find the total sulfur titrated to the nearest 1 ~tg. Subtract the 40 ~tg added. 11.6 For blank determinations, repeat the operations in 8.3 and 8.7, and burn a hydrocarbon stock with a very low or nondetectable sulfur content. Burn for the same length of time as the sample in the normal liquid mode. Subtract from the sulfur figures in 11.5 any blank so obtained. This is the net micrograms of sulfur from the sample. 430

13. Reagents 13.1 Alcohol-Glycerin Mixture--Mix 2 volumes of denatured ethyl alcohol conforming to Formula No. 3A of the U.S. Bureau of Internal Revenue or ethyl alcohol (99 % by volume) with 1 volume of glycerin. 13.2 Barium Chloride Dihydrate (BaCl2. 2H20)--Crystals passing a 20-mesh (850-1~m) sieve and retained on a 30-mesh (600-ttm) sieve conforming to Specification E 11. NOTE 16--The crystal size of the BaCI2.2H20 is an important variable that affectsthe developmentof turbidity. 13.3 Hydrochloric Acid (l+12)--Add 77 mL of concentrated hydrochloric acid (HCI, relative density 1.19) to a I-L volumetric flask and dilute to the mark with water. 14. Calibration 14.1 Only by the most scrupulous care and attention to details can reliable results be obtained by this method. Before using new glassware and thereafter as required, clean the glassware with concentrated nitric acid. Rinse three times with tap water and follow with three rinses of deionized water. Reserve the glassware for use in this method alone. 14.2 Into 50-mL volumetric flasks introduce, by means of the buret, 0.25, 0.50, 0.75, 1.00, 1.50, 2.00, 3.00, and 5.00 mL of standard sulfate solution (1 mL = 100 ttg S). See 6.3. Add 3.0 mL of HCI (1+12) to each flask, dilute to volume with water, and mix thoroughly. Prepare a reagent blank standard in a similar way, omitting the standard sulfate. 14.3 Pour the entire contents of each flask into a 10O-rnL beaker. Add by means of a pipet 10 + 0.1 mL of alcoholglycerin mixture and mix for 3 rain on the magnetic stirrer. Select a stirring speed just below that which might cause loss of sample through splashing. Maintain this speed throughout the entire procedure. 14.4 Allow the solution to stand undisturbed for 4 min. Transfer to an absorption cell and measure the initial absorbance, using water as reference. 14.5 Return the solution to the beaker and add 0.30 + 0.01 g of BaCI2.2H20 crystals, either by weighing this amount or by using the scoop. Stir with the magnetic stirrer for exactly 3 rain. Allow to stand for an additional 4 rain, transfer to the cell, and again measure the absorbance relative to water.

(~ D 2784 15.5 Convert net absorbance to micrograms of sulfur by using the calibration curve.

14.6 Following steps described in 14.3, 14.4, and 14.5, obtain a reagent blank reading by subtracting the initial absorbance of the reagent blank standard from that obtained after addition of BaCI2.2H20. This reading should not exceed 0.005. 14.7 Obtain the net absorbance for each standard by subtracting the initial ahsorbance and reagent blank reading from the absorbance obtained in accordance with 14.5. Plot the net absorbance of each standard against micrograms of sulfur contained in 50 m L of solution and draw a smooth curve through the points. 14.8 To detect possible shifts, check the calibration curve daily by making single determinations.

16. Calculation 16.1 Calculate the amount of sulfur in the sample as follows: Sulfur content, ~tg/g = A/W (1) where: A = micrograms of sulfur as obtained in 11.6 or 15.6, and W = grams of sample burned. 16.1.1 Round the result of the test to the nearest 1 ~tg/g of sulfur. 16.2 Alternatively calculate the concentration in units of grains of total sulfur per 100 ft3 as follows: R (for propane) -- 0.083S R (for butane) = 0.11 IS (2) R (for propane-butane mixtures) -- S[0.366(G - 0.5077) + 0.083] where: R = grains of total sulfur per 100 ft 3 of gas at 15.6°C (60"F) and 0.10132 MPa (760 mm) Hg, S = sulfur content, ~tg/g, and G = relative density of the mixture at 15.6/15.6"C (60/60"F).

15. Procedure for Analysis of Absorber Solutions 15.1 Drain the absorber solution into a 250-mL beaker and quantitatively rinse the absorber collecting the rinsings in the beaker. 15.2 Reduce the volume of the absorber solutions to about 25 mL by evaporation on a hot plate. Quantitatively transfer the resultant solution to a 50-mL volumetric flask, rinsing the beaker with several small portions of water. Add 3 mL of HCI (1+12) to the flask, make up to volume with water, and mix thoroughly. 15.3 Into a 100-mL beaker pour the entire contents of the 50-mL volumetric flask containing the solution to be analyzed. Proceed as directed in 14.3, 14.4, and 14.5.

NOTE 18raThe derivatives of constants used in the above equations are based on the followingproperties of propane and butane: Specific volume for propane (of the real gas at 60*F 8.4515 and 14.696 psia), ft3/lb of gas Specific volume for butane (same conditions as 6.3120 above) NOTE 19--If the relative density of the mixture is not known, determine it by Test Method D 1657. NOTE 20--Multiply by 2.2883 to convert grains per cubic foot to grams per cubic metre. Multiply by 35.31 to convert grains per cubic foot to grams per cubic metre.

NOTE 17--Should the blank reading exceed 0.020, the precision obtainable will be impaired. If so, make an analysis of the reagents alone to determine whether the atmosphere or reagents are at fault. Place 30 mL of the H202 (1.5 %) in the 50-mL volumetric flask, dilute to the mark with HCI (1+215), and proceed as describedin 14.6. If this reagent blank reading exceeds0.010, results should not be considered reliable.

17, Precision and Bias 17.1 The precision of this test method has not been determined. The responsible subcommittee is attempting to attract volunteers for an interlaboratory study. 17.2 The bias of this test method cannot be determined since appropriate reference material containing a known level of sulfur in liquified petroleum gases is not available.

15.4 Obtain the net absorbance ofthe analysis solution by subtracting the initial absorbance and the net absorbance for the oxy-hydrogen combustion blank or the lamp combustion (depending upon the apparatus used for combustion) from that obtained after the addition of BaC12.2H20.

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and ff not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend. If you feel that your comments have not received e fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103.

431

,tflTt

Designation: D 2 7 8 6 - 91

An American National Standard

Standard Test Method for Hydrocarbon Types Analysis of Gas-Oil Saturates Fractions by High Ionizing Voltage Mass Spectrometry I This standard is issued under the fixed designation D 2786; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (0 indicates an editorial change since the last revision or reapproval.

1. Scope 1.1 This test method2 covers the determination by high ionizing voltage mass spectrometry of seven saturated hydrocarbon types and one aromatic type in saturate petroleum fractions having average carbon numbers 16 through 32. The "saturate types include alkanes (0-rings), single-ring naphthenes, and five fused naphthene types with 2, 3, 4, 5, and 6 rings. The nonsaturate type is monearomatic. Noncondensed naphthenes are analyzed as single rings. Samples must be nonolefinic and must contain less than 5 volume % monoaromatic. Composition data are in volume percent. 1.2 The values stated in acceptable SI units are to be regarded as the standard. The values given in parentheses are provided for information purposes only. 1.3 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 2. Referenced Documents

2.1 ASTM Standards: D2549 Test Method for Separation of Representative Aromatics and Nonaromatics Fractions of High-Boiling Oils by Elution Chromatography3 D3239 Test Method for Aromatic Types Analysis of Gas-Oil Aromatic Fractions by High Ionizing Voltage Mass Spectrometry3 E 137 Practice for Evaluation of Mass Spectrometers for Quantitative Analysis from a Batch InleP 3. Terminology 3.1 Descriptions of Terms Specific to This Standard." 3.1.1 Characteristic Mass Groupings: 3.1.1.1 2371 =71 + 8 5 + 9 9 + ll3(alkanes). (l)

3.1.1.2 Y~69-- 69 + 83 +97 + 111 + 125+ 139 (l-ring).

(2) 3.1.1.3 2; 109 = 109 + 123 + 137 + 151 + 165 + 179 + 193 (2-ring). (3) 3.1.1.4 23 149 = 149 + 163 + 177 + 191 + 205 + 219 + 233 + 247 (3-ring). (4) 3.1.1.5 Y~189 = 189 + 203 + 217 + 231 + 245 + 259 + 273 + 287 + 301 (4-ring). (5) 3.1.1.6 Y ~ 2 2 9 = 2 2 9 + 2 4 3 + 2 5 7 + 2 7 1 + 2 8 5 + 2 9 9 + 313 + 327 + 341 + 355 (5-ring). (6) 3.1.1.7 23 269 = 269 + 283 + 297 + 311 + 325 + 339 + 353 + 367 + 381 + 395 + 409 (6-ring). (7) 3.1.1.8 2391 = 91 + 105 + 117 + 119 + 129 + 131 + 133 + 143 + 145 + 147 + 157 + 159 + 171 (monoaromatic).(8)

4. Summary of Test Method 4.1 The relative abundance of alkanes (0-ring), 1-ring, 2-ring, 3-ring, 4-ring, 5-ring, and 6-ring naphthenes in petroleum saturate fractions is determined by mass spectrometry using a summation of mass fragment groups most characteristic of each molecular type. Calculations are carried out by the use of inverted matrices (derived from ion intensity calibration sensitivities) that are specific for any average carbon number. The saturate fraction is obtained by liquid elution chromatography, see Test Method D 2549. 5. Significance and Use 5.1 A knowledge of the hydrocarbon composition of process streams and petroleum products boiling within the range of 205 to 540°C (400 to 1000°F) is useful in following the effect of changes in process variables, diagnosing the source of plant upsets and in evaluating the effect of changes in composition on product performance properties. 5.2 This test method, when used together with Method D 3239, provides a detailed analysis of the hydrocarbon composition of such materials. 6. Apparatus 6.1 Mass SpectrometerwThe suitability of the mass spectrometer to be used with this method shall be proven by performance tests described both herein and in Recommended Practice E 137. 6.2 Sample Inlet System--Any inlet system may be used that permits the introduction of the sample without loss, contamination, or change in composition. The system must function in the range from 125 to 350°C to provide an appropriate sampling device. 6.3 Microburet or Constant-Volume Pipet.

J This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.04 on Hydrocarbon Analysis. Current edition approved Oct. 15, 1991. Published December 1991. Originally published, as D 2786 - 69. Last previous edition, D 2786 - 86. 2 Hood, A., and O'Neal, M. J., Advances in Mass Spectrometry, AMSPA, Waldron, 1959, p. 175. 3 Annual Book of ASTM Standards, Vol 05.02. 4 Annual Book of ASTM Standards, Vol 05.03.

432

~

D 2786

7. Reagents 7.1 n-Hexadecane. NOTE l: Warning--Combustible. Vapor harmful.

8. Calibration 8.1 Calibration matrix inverses are attached in Table 1 which may be used directly provided the following procedures are followed. 8.2 Instrumental Conditions~Repeller settings are adjusted to optimum based on role 226 ion of n-hexadecane. A magnetic field is used that will permit a scan over the mass range 65 to 410 role. An ionization voltage of 70 eV and an ionizing current in the range l0 to 70 ~A is used. NOTE 2--The instrument conditions and calibration matrix inverses described in this method are based on the use of a 180" magneticdeflection type mass spectrometer(CEC Model 21-103). It is not known if the calibration matrix inverses, included in this method, are suitable for use on other mass spectrometer types. 8.3 Calibration Standard--The calibration coefficients in this method were obtained for ion source conditions such that the 2; 69/2; 71 ratio was 0.20/1.0 for n-hexadecane. The cooperative study of this method indicated an acceptable range for the 2; ratio was between 0.18 to 0.22.

d = deisotoped C,,H2,+~ peak at two carbon numbers less than the average C,H2,+2 peak (n-paraffin peak - 29 mass units), and r -- ratio. If r is 0.50 or higher, use the respective n-paraffin inverse coefficients; otherwise use the isoparaffin inverse coefficients. Interpolate where necessary. Sensitivity Factors Average Carbon No. 16 20 24 28 32

n-Paraffins

Isoparaffins

0.347 0.606 1.250 2.439 4.000

0.0364 0.0505 0.0735 0.1061 0. | 380

NOTE 4--The sensitivity factors in the above table are valid when the mass spectrometer is operated in such a mode as to give a 127/226 ratio for n-hexadecane of 1.4, approximately. If this ratio cannot be attained, an individual laboratory should replace the above factors with sensitivity data representative of actual instrument operation.

10.4 After the proper inverse has been selected, carry out the following calculations: a -- (bit|) 4- (b2c2) 4- (b3c3) 4- . . . 4- (bscs) (10) where: a = partial ion intensity of alkanes, b~ = Z 71, b E = 2; 69, etc., and cl = Z 71 inverse, c2 = 2; 69 inverse, etc. Repeat the corresponding calculation to obtain a solution for 1-ring, 2-ring, 3-ring, etc. 10.5 Normalize all partial ion intensities to 100.0 and report as volume percent.

9. Procedure 9.1 If the mass spectrometer has been in continuous operation, no additional preparation is necessary before analyzing samples. However, if the spectrometer has been turned on only recently, check its operation according to the manufacturer's instructions to ensure stability before proceeding. 9.2 Obtain the mass spectrum of the sample, scanning from mass 67 to 409.

10. Calculation 10.1 Recording Mass Spectra--Read peak heights from the mass spectrum of the sample corresponding to the role+ itemized under 3.1.1.1 to 3.1.1.8, inclusive, and correct all peaks for heavy isotopes by the use of the two peaks immediately preceding the peak to be corrected. 10.2 Form the peak summations described under 3.1.1.1 to 3.1.1.8, inclusive. 10.3 Selection of Proper Inverse from Table 1: NOTE 3--Sample history and physical property data provide the best

criteria for inverse selection and are preferred, if available, over the described procedure. 10.3.1 The carbon number of the largest deisotoped CnH2n+2 peak is assumed to be the average carbon number.

10.3.2 The following equation will determine whether the iso or normal inverse coefficients should be used. Set = (ab)/[(ab) + (cat)] = r (9) where: a = respective normal paraffin sensitivity factor from the table below, b = deisotoped average CnHEn+2 peak (corresponds to molecular weight of n-paraffin), c = respective isoparaffin sensitivity factor from the table below,

11. Precision and Bias 11.1 The precision of this test method as obtained by statistical examination of interlaboratory test results on a sample having the composition given in Table 2, is as follows: 1 l.l.1 RepeatabilitymThe difference between successive test results obtained by the same operator with the same apparatus under constant operating conditions on identical test material, would in the long run, in the normal and correct operation of the test method, exceed the values shown in Table 2 only in one case in twenty. 11.1.2 Reproducibility--The difference between two single and independent results, obtained by different operators working in different laboratories on identical test material, would in the long run, in the normal and correct operation of the test method, exceed the values shown in Table 2 only in one case in twenty. NOTE 5mIf samples are analyzed that differ appreciably in composition from the sample used for the inteflaboratory study, this precision statement may not apply.

l 1.2 BiasmThe quantities determined are defined by the conditions employed in this empirical method, and a statement of bias is therefore not appropriate. 12. Keywords 12.1 gas oil; mass spectrometry; petroleum; saturates

433

(1~ D 2786 TABLE 1 71

Z 69

~ 109

Calibration Matrix Inverses Z 149

Z 189

¢ 229

~ 269

Z 91

C~e Inverse n-Alkanes 0 Ring 1 Ring 2 Ring 3 Ring 4 Ring MA Iso~kanes 0 Ring 1 Ring 2 Ring 3 Ring 4 Ring MA

0.5344 -0.0610 -0.0039 0.0000 0.0001 -0.0007

-0.0292 0.3403 0.0170 -0.0004 0.0004 -0.0029

-0.0066 -0.2146 0,8491 +0.0115 0.0039 -0.0237

0.0215 -0.1162 -0.6968 1,7220 -0,0138 -0.1566

0.0299 -0,0362 -0.3420 -1.3545 3.2594 -0,3494

0.6543 -0.0866 -0.0053 0.0001 0.0000 0.0001

-0.0358 0.3416 0.0172 -0.0004 0.0004 -0.0029

-0.0081 -0.2143 0.8492 0.0115 0.0039 -0,0237

0.0264 -0.1171 -0.6968 1.7220 -0.0138 -0.1565

0.0366 -0.0377 -0.3420 -1.3545 3.2594 -0.3493

o . .

, . o

. ° .

. . o

o o .

. . °

0

a

m

-0.0151 -0.0112 -0.0048 0.0152 -0.0485 0,3521 -0.0165 -0.0101 -0.0046 0.0152 -0.0485 0.3521

, , .

. o .

C~71nverse n-Alkanes 0 Ring 1 Ring 2 Ring 3 Ring 4 Ring MA Isoalkanes 0 Ring 1 Ring 2 Rmg 3 Ring 4 Ring MA

0.5243 -0.0660 -0.0038 0.0000 0.0001 -0.0007

-0.0311 0.3403 0.0154 -0.0004 0.0004 -0.0027

-0.0075 -0.2130 0.8375 0.0095 0.0039 -0.0220

0.0227 -0.1164 -0.6826 1.6824 -0.0147 -0.1514

0.0322 -0.0385 -0.3318 -1.3111 3.1247 -0.3331

0.6435 -0.0942 -0.0054 0.0000 0.0000 0.0000

-0.0382 0.3418 0.0155 -0.0002 0.0004 -0.0027

-0.0092 -0.2125 0.8375 0.0090 0.0040 -0.0220

0.0279 -0.1176 -0.6826 1.6825 -0.0147 -0.1514

0.0395 -0.0403 -0.3319 -1.3111 3.1247 -0.3331

o ° .

q

q

qd

, . ,

o o .

-0.0163 -0.0121 -0.0052 0.0166 -0.0527 0.3612 -0.0200 -0.0112 -0.0052 0,0166 -0.0527 0.3612

. . o

. o o

. ° .

C~e Inverse n-Alksnes 0 Ring 1 Ring 2 Ring 3 Ring 4 Ring MA Isoalkanes 0 Ring 1 Ring 2 Ring 3 Ring 4 Ring MA

-0.0178 -0,0136 -0.0057 0,0179 -0.0567 0.3677

0.5175 -0.0720 -0.0039 0.0000 0.0301 -0.0007

-0.0338 0.3404 0.0138 -0.0003 0.0004 -0.0025

-0.0085 -0.2091 0.8183 0.0062 0.0040 -0.0206

0.0234 -0.1183 -0.6626 1.6426 -0.0158 -0.1445

0.0344 -0.0404 -0.3213 -1.2734 3.0158 -0.3010

0.6335 -0.1016 -0.0054 0.0000 0.0000 -0.0002

-0.0414 0.3424 0,0140 -0.0003 0.0004 -0.0025

-0.0103 -0,2086 0,81 64 0.0062 0.0040 -0.0206

0.0286 -0.1197 -0,6626 1.6426 -0.0158 -0.1445

0.0422 -0,0424 -0.3214 -1.2784 3.0158 -0.3200

-0.0215 -0.0126 -0.0056 0,0179 -0.0566 0.3677

~

0

t

•

•

Q

C~9 Inverse n-Alkanes 0 Ring 1 Ring 2 Ring 3 Ring 4 Ring MA Isoalkanes 0 Ring 1 Ring 2 Ring 3 Ring 4 Rang MA

0.5109 -0.0773 -0.0038 0,0000 0.0001 -0.0008

-0.0363 0.3396 0.0118 -0.0003 0.0004 -0.0023

-0.0094 -0.2080 0,8076 0.0032 0.0041 -0,0192

0.0202 -0.1161 -0.6491 1.6068 -0.0179 -0.1369

0.0404 -0.0413 -0.3184 -1.2432 2.9192 -0.2980

-0.0190 -0.0154 -0.0061 0.0193 -0,0614 0.3764

0.6239 -0.1079 -0.0053 0.0000 0.0001 -0,0004

-0.0443 0.3418 0,0120 -0.0002 0.0004 -0,0023

-0.0115 -0,2073 0.8077 0.0030 0.0041 -0.0192

0.0246 -0.1173 -0.6493 1.6068 -0.0179 -0.1369

0.0494 -0.0438 -0.3184 -1.2432 2.9192 -0.2980

-0.0232 -0.0142 -0.0061 0.0193 -0.0614 0.3764

434

(1~ D 2786 TABLE 1 Z 71

Z 69

Z 109

Continued ~ 149

~ 189

~ 229

~ 269

¢ 91

C2olnverse n-Alkanes 0 Ring 1 Ring 2 Ring 3 Ring 4 Ring 5 Ring MA Isoalkanes 0 Ring 1 Ring 2 Ring 3 Ring 4 Ring 5 Ring MA

-0.0397 0.3403 0.0097 -0.0003 0.0000 0.001 -0.0022

0,0105 -0,2066 0.7972 -0.0014 0.0012 0.0085 -0.0188

0.0183 -0.1137 -0.6412 1.5634 -0.0409 0.0630 -0.1382

0.0458 -0.0418 -0,3106 -1.2179 2.7690 0.0996 -0,2910

0.0412 0.0375 -0.1542 -0.5944 -1.4656 4.2055 -0.4521

0.6188 -0.1151 -0.0051 0.0001 0.0000 0.0003 -0,0007

-0.0481 0.3427 0.0098 -0,0003 0.0000 0.0010 -0.0022

-0.0127 -0.2059 0.7972 -0.0014 0.0012 0.0085 -0.0188

0.0222 -0.1149 -0.6412 1.5634 -0.0409 0,0630 -0.1382

0.0555 -0.0446 -0.3107 -1.2179 2.7690 0.0996 -0.2910

0.0499 0.0350 -0.1544 -0.5944 -1.4656 4,2054 -0.4521

-0.0270 -0.0176 0.0001 0.0468 -0.0029 -0.1831 0.4049

C21

n-Alkanes 0 Ring 1 Ring 2 Ring 3 Ring 4 Rtng 5 Ring MA Isoalkanes 0 Ring 1Rmg 2 Ring 3 Ring 4 R=ng 5 Ring MA

Inverse

-0.0431 0.3393 0.0074 -0.0002 0,0000 0.0009 -0.0020

-0.0119 -0.2025 0.7808 -0.0037 0.0014 0.0078 -0.0173

0.0195 -0.1147 -0.6176 1,5192 -0.0416 0.0592 -0.1308

0.0454 -0.0429 -0.3082 -1.1698 2.6715 0.0898 -0.2717

0.0441 0,0334 -0.1470 -0,5596 -1.4243 3.9781 -0.4172

-0.0242 -0.0212 -0.0003 0.0483 -0.0056 -0.1851 -0.4123

0.6140 -0.1216 -0.0048 -0.0001 0.0000 0.0005 -0.0010

-0.0522 0.3421 0.0076 -0.0002 0.0000 0.0009 -0.0020

-0.0144 -0.2016 0.7811 -0.0037 0.0014 0.0078 -0.0173

0.0235 -0.1158 -0.6176 1.5192 -0.0416 0.0592 -0.1308

0.0550 -0.0458 -0.3082 -1.1698 2.6715 0.0893 -0.2717

0.0533 0.0305 -0.1472 -0.5596 -1.4232 3.9781 -0.4172

-0.0292 -0.0196 -0,0001 0.0483 -0.0056 -0.1851 0,4123

Inverse

0.5084 -0.0946 -0.0030 -0.0002 0.0000 0.0004 -0.0010

-0.0474 0.3397 0.0050 0.0000 0.0000 0.0008 -0.0018

-0.0133 -0.1995 0.7661 -0.0072 0.0018 0.0072 -0.0161

0.0210 -0.1145 -0.6016 1.4778 -0.0411 0.0564 -0.1252

0.0435 -0.0440 -0.3016 -1.1214 2.5629 0.0829 -0.2574

0.0484 0.0307 -0.1444 -0.5559 -1.3179 3.7619 -0.3897

-0.0263 -0,0240 -0.0005 0.0517 -0.0117 -0.1690 0.4237

0.6096 -0.1267 -0,0044 -0.0003 0.0001 0.0007 -0.0015

0.0568 0.3427 0.0053 0.0000 0,0000 0.0008 -0.0018

-0.0160 -0.1986 0.7662 -0.0072 0,0018 0,0072 -0.0161

0.0252 -0,1158 -0.6016 1.4778 -0.0411 0.0564 -0.1253

0.0521 -0.0468 -0,3018 -1.1213 2.5629 0.0829 -0.2574

0.0580 0.0277 -0.1445 -0.5559 -1.3179 3.7619 -0.3897

-0.0316 -0.0223 -0.0004 0.0517 -0.0177 -0.1890 0.4238

C23

n-Alkanes 0 Ring 1 Ring 2 Ring 3 Ring 4 Ring 5 Ring MA Isoalkanes 0 Ring 1 Ring 2 Ring 3 Ring 4 Ring 5 Ring MA

o,. .°.

0.5077 -0.0888 -0.0033 -0.0001 0.0000 0.0004 -0.0009

C22

n-Alkanes 0 Ring 1 Ring 2 Rtng 3 Ring 4 Ring 5 Ring MA Isoalkanes 0 Ring 1 Ring 2 Ring 3 Ring 4 Ring 5 Ring MA

-0.0223 -0.0190 0.0000 0.0468 -0.0029 -0.1831 0.4049

0.5099 -0.0835 -0.0036 0.0000 0.0000 0.0004 -0.0008

°,.

inverse

0.5093 -0.1003 -0.0024 -0.0002 0.0001 0.0005 -0.0011

-0.0518 0.3404 0.0021 0.0001 0.0000 0.0007 -0.0017

-0.0153 -0.1976 0,7580 -0.0103 0,0020 0.0066 -0.0148

0.0226 -0.1142 -0.5880 1.4393 -0.0425 0.0539 -0.1189

0.0407 -0.0446 -0,3011 - 1.0839 2.4806 0,0750 -0.2409

0.0521 0.0282 -0.1405 -0.5414 -1.2840 3.6015 -0.3560

-0.0285 -0.0269 -0.0008 0.0542 -0.0149 -0.1927 0.4300

0.6093 -0.1338 -0.0038 -0.0004 0.0001 0.0009 -0.0190

-0.0619 0.3439 0.0023 0.0001 0.0000 0.0007 -0.0016

-0.0183 -0.1965 0,7580 -0.0103 0.0020 0.0066 -0.0148

0.0270 -0.1156 -0.5882 1.4393 -0.0426 0.0539 -0,1189

0.0487 -0.0473 -0.3013 - 1.0839 2.4806 0.0750 -0.2410

0.0624 0.0246 -0.1406 -0.5415 -1,2840 3.6016 -0.3561

-0.0341 -0.0250 -0.0008 0.0542 -0.0149 -0.1927 0.4300

435

(~ D 2786 TABLE 1 2; 71

2; 69

Z 109

Continued 2; 149

2; 189

2; 229

2; 269

2; 91

C24 Inverse n-Alkanes 0 Ring 1 Ring 2 Ring 3 Ring 4 Ring 5 Ring 6 Ring MA Isoalkenes 0 Ring 1 Ring 2 Ring 3 Ring 4 Ring 5 Ring 6 Ring MA

0.5105 -0.1061 -0.0016 -0.0003 0.0000 0.0004 0.0005 -0.0012

-0.0566 0.3414 -0.0011 0.0004 -0,0001 0.0005 0.0006 -0.0015

-0.0174 -0.1960 0.7505 -0.0146 0.0014 0.0048 0.0055 -0.0143

0.0249 -0.1128 -0.5807 1.4098 -0.0506 0.0407 0.0457 -0.1190

0.0434 -0.0420 -0.2908 -1.0564 2,3673 0.0457 0.0911 -0.2369

0.0528 0.0288 -0.1418 -0.5371 -1.2328 3.3827 0.1138 -0.3388

0.0372 0.0761 0.0047 -0.2987 -0.6560 -0.9376 3.9809 -0.4136

-0.0324 -0.0337 -0.0011 0.0706 0,0085 -0.1544 -0,1763 0.4594

0.6094 -0.1403 -0,0032 -0.0006 0,0003 0.0009 0,0010 -0.0026

-0.0675 0,3451 -0.0009 0.0004 -0.0001 0.0005 0.0005 -0.0014

-0.0208 -0.1948 0.7506 -0.0145 0.0014 0.0048 0.0055 -0.0142

0.0297 -0.1145 -0.5808 1,4098 -0,0506 0.0407 0.0457 -0.1190

0.0518 -0.0449 -0,2910 -1.0564 2.3673 0.0457 0,0911 -0.2370

0,0631 0.0253 -0.1420 -0.5352 -1.2328 3.3828 0.1139 -0.3389

0.0444 0.0736 0,0045 -0.2986 -0.6560 -0.9376 3.9809 -0,4137

-0.0397 -0.0315 -0.0010 0.0706 0.0085 -0.1544 -0.1764 0.4595

C2s Inverse n-Alkanes 0 Ring 1 Ring 2 Ring 3 Ring 4 Ring 5 Ring 6 Ring MA Isoalkanes 0 Ring 1 Ring 2 Ring 3 Ring 4 Ring 5 Ring 6 Ring MA

0.5132 -0.1115 -0.0009 -0.0005 0,0300 0.0005 0.0005 -0.0013

-0,0621 0.3425 -0.0040 0.0006 -0.0001 0.0005 0.0005 -0.0014

-0.0196 -0.1930 0.7378 -0.0185 0.0019 0.0043 0.0048 -0.0128

0.0262 -0.1133 -0.5623 1.3763 -0,0520 0.0389 0.0424 -0.1125

0.0471 -0,0435 -0.2821 -1.0229 2.2834 0.0409 0.0836 -0,2213

0.0493 0.0302 -0,1450 -0,5229 -1.1777 3.2347 0.1304 -0.3157

0.0383 0.0753 -0.0032 -0,2858 -0.6213 -0.8915 3,7174 -0.3738

-0.0344 -0.0380 -0.0005 0.0741 0.0034 -0.1577 -0.1753 0.4652

0,6096 -0.1449 -0.0023 -0.0008 0.0000 0.0011 0.0012 -0.0032

-0.0738 0.3465 -0.0039 0.0007 -0.0001 0.0004 0,0004 -0.0012

-0.0233 -0.1918 0.7378 -0.0185 0.0019 0.0043 0.0048 -0.0127

0.0311 -0.1150 -0.5624 1.3762 -0.0520 0.0389 0.0424 -0.1126

0.0559 -0.0461 -0.2821 -1.0229 2.2834 0.0410 0.0836 -0.2215

0.0586 0,0256 -0.1452 -0.5229 -1.1777 3.2347 0,1034 -0.3159

0,0455 0.0727 -0.0032 -0.2857 -0.6213 -0.8914 3.7175 -0.3740

-0.0409 -0.0358 -0.0005 0,0741 0,0034 -0.1578 -0.1754 0.4653

C2e Inverse n-Alkanes 0 Ring 1 Ring 2 Ring 3 R~ng 4 Ring 5 Ring 6 Ring MA Isoalkanes 0 Ring 1 Ring 2 Ring 3 Ring 4 Ring 5 Ring 6 Ring MA

0.5161 -0.1166 0.0003 -0.0005 0.0000 0.0005 0.0005 -0.0014

-0.0679 0.3429 -0.0080 0.0010 -0.0001 0,0004 0,0005 -0.0012

-0.0225 -0.1912 0.7313 -0.0225 0.0023 0.0339 0.0044 -0.0118

0.0282 -0.1146 -0.5486 1.3441 -0.0526 0.0372 0.0402 -0.1079

0.0500 -0.0445 -0.2776 -0.9981 2.2145 0.0355 0.0776 -0.2080

0.0496 0.0291 -0.1391 -0.4986 -1.1323 3.0605 0.0914 -0.2863

0.0388 0.0764 -0.0096 -0.2786 -0.5916 -0.8433 3.4893 -0.3450

-0.0369 -0.0425 -0.0006 0.0779 -0.0014 -0.1603 -0.1773 0,4762

0.6106 -0.1513 -0.0012 -0.0011 0.0001 0.0013 0.0015 -0,0040

-0.0804 0.3475 -0.0078 0.0011 -0.0001 0.0003 0.0003 -0.0009

-0.0267 -0.1897 0,7315 -0.0225 0.0023 0.0039 0.0044 -0.0117

0.0334 -0.1165 -0.5487 1.3441 -0.0526 0,0372 0.0402 -0.1081

0.0592 -0.0479 -0.2778 -0.9981 2.2145 0.0356 0.0777 -0.2083

0.0586 0.0254 -0.1393 -0.4986 -1.1323 3.0606 0.0915 -0.2885

0.0459 0.0700 -0.0100 -0.2786 -0.5916 -0.8433 3.4894 -0.3452

-0,0436 -0.0401 -0.0002 0.0779 -0.0014 -0.1604 -0.1774 0.4763

0.0543 -0.0461 -0.2754 -0.9676 2.1375 0,0310 0.0704 -0.1933

0.0504 0.0276 -0.1418 -0.4789 -1.0763 2.9059 0.0814 -0.2678

0.0374 0.0696 -0.0158 -0,2650 -0,5666 -0.7842 3.2533 -0.3125

-0.0393 -0.0477 0.0000 0.0810 -0.0083 -0.1629 -0.1756 0,4834

C27Inverse n-Alkanes 0 Ring 1 Ring 2 Ring 3 Ring 4 Ring 5 Ring 6 Ring MA

0.5207 -0,2119 0.0014 -0,0008 0.0001 0.0005 0.0006 -0.0015

-0.0742 0.3430 -0.0118 0,0014 -0.0001 0.0004 0,0004 -0.0011

-0.0259 -0.1872 0.7203 -0.0270 0.0027 0.0035 0.0039 -0.0106

0.0301 -0.1135 -0.5347 1.3144 -0.0532 0.0355 0,0373 -0.1027

436

~1~ D 2786 TABLE 1 2; 71

2; 69

2; 109

Continued ;~ 149

2; 189

2; 229

2; 269

2; 91

0.0637 -0.0497 -0.2756 -0.9677 2.1375 0.0300 0.0706 -0.1937

0.0592 0.0238 -0.1420 -0.4789 -1.0763 2.9060 0.0815 -0.2681

0.0439 0.0672 -0.0160 -0.2650 -0.5666 -0.7842 3.2534 -0.3127

-0,0462 -0.0450 0.0001 0.0811 -0.0083 -0.1630 -0.1757 0.4836

C27inverse Continued Isoalkanes 0 Ring 1 Rmg 2 Ring 3 Ring 4 Ring 5 R=ng 6 Ring MA

0.6117 -0.1562 0.0000 -0.0014 0.0001 0.0016 0.0017 -0.0048

-0.0872 0.3479 -0.0116 0,0015 -0.0002 0.0002 0.0002 -0.0006

-0,0305 -0.1855 0.7204 -0.0270 0.0027 0.0035 0.0038 -0.0105

0.0354 -0.1155 -0.5348 1,3144 -0.0532 0.0356 0.0374 -0.1028

C2ainverse n-Alkanes 0 Ring 1 Ring 2 Ring 3 Ring 4 Ring 5 Ring 6 Ring MA Isoalkanes 0 Ring 1 Ring 2 Ring 3 Ring 4 Ring 5 Ring 6 Ring MA

0.5245 -0,1275 0.0032 -0.0010 0.0001 0.0006 0.0006 -0.0017

-0.0815 0.3448 -0.0165 0.0019 -0.0002 0.0003 0.0003 -0.0009

-0.0296 -0.1848 0.7148 -0.0304 0.0031 0,0032 0.0035 -0.0097

0.0332 -0.1140 -0.5230 1.2771 -0.0538 0.0340 0.0355 -0.0981

0.0579 -0.0466 -0.2670 -0.9282 2.0568 0.0263 0.0667 -0.1837

0.0525 0.0253 -0.1396 -0.4724 -1.0243 2.7716 0.0725 -0.2444

0.0346 0.0698 -0.0208 -0.2582 -0.5430 -0.7622 3.0949 -0.2892

-0,0419 -0.0545 0.0003 0.0855 -0.0142 -0.1666 -0.1791 0.4945

0.6174 -0.1625 0.0016 -0.0018 0.0002 0.0020 0.0021 -0.0058

-0.0959 0.3502 -0.0162 0.0021 -0.0002 0.0001 0.0001 -0.0003

-0,0349 -0.1827 0.7149 -0.0304 0.0031 0.0031 0.0034 0.0094

0.0390 -0.1163 -0.5232 1.2771 -0.0538 0.0341 0.0356 -0.0983

0.0682 -0.0504 -0.2671 -0.0283 2.0568 0.0264 0.0669 -0.1841

0.0618 0.0217 -0.1396 -0.4725 -1.0243 2.7717 0,0726 -0.2448

0,0408 0.0676 -0.0209 -0.2583 -0.5430 -0.7621 3.0950 -0.2895

-0.0493 -0.5016 0.0004 0.0855 -0.0142 -0.1667 -0.1792 0.4948

C29inverse n-Alkanes 0 Ring 1 Ring 2 Ring 3 Ring 4 Ring 5 Ring 6 Ring MA Isoalkanes 0 Ring 1 Ring 2 Ring 3 Ring 4 Ring 5 Ring 6 Ring MA

0.5305 -0.1342 0.0049 -0.0013 0.0002 0.0006 0.0006 -0.0018

-0.0902 0,3482 -0.0214 0.0025 -0.0002 0.0003 0,0003 -0.0008

-0.0337 -0.1825 0.7054 -0,0356 0.0037 0.0027 0.0029 -0.0086

0.0353 -0.1143 -0.5089 1.2520 -0,0558 0,0322 0.0327 -0.0925

0.0639 -0.0495 -0.2628 -0.8991 1.9849 0.0216 0.0612 -0.1724

0.0565 0.0225 -0.1371 -0.4619 -0.9773 2.6445 0.0656 -0.2300

0.0347 0.0668 -0.0261 -0.2492 -0.5067 -0.7174 2.8747 -0.2603

-0.0441 -0.0613 0.0007 0.0900 -0,0237 -0.1685 -0.1773 0.5016

0.6202 -0.1684 0.0033 -0.0023 0.0004 0.0023 0.0024 -0.0068

-0.1065 0.3540 -0.0211 0.0027 -0.0003 0.0000 0.0000 0.0001

-0.0394 -0.1803 0.7054 -0.0356 0.0036 0.0027 0.0030 -0.0079

0.0413 -0.1166 -0.5091 1.2520 -0.0557 0,0323 0.0328 -0.0928

0.0747 -0.0536 -0.2631 -0.8992 1.9850 0.0218 0.0614 -0.1730

0.0661 0.0189 -0.1372 -0.4620 -0.9773 2.6447 0.0658 -0.2305

0.0406 0.0644 -0.0263 -0.2494 -0.5067 -0,7172 2.8748 -0.2606

-0.0515 -0.0584 0.0008 0.0901 -0.0237 -0.1686 -0.1775 0.5020

C3o inverse n-Alkanes 0 Ring 1 Ring 2 Ring 3 Ring 4 Ring 5 Ring 6 Ring MA Isoalkanes 0 Ring 1 Ring 2 Ring 3 Ring 4 R~ng 5 Ring 6 R=ng MA

0.5352 -0.1397 0.0071 -0.0015 0,0002 0.0007 0.0007 -0.0020

-0.0989 0.3508 -0.0272 0,0033 -0.0003 0.0002 0.0002 -0.0006

-0.0388 -0.1801 0.7014 -0,0408 0,0042 0.0024 0.0027 -0.0079

0.0385 -0.1125 -0.5010 1.2276 -0.0580 0.0301 0.0300 -0.0864

0.0707 -0.0526 -0.2562 -0.8689 1.9167 0.0176 0.0570 -0.1632

0.0600 0.0196 -0.1355 -0.4464 -0.9357 2.5139 0.0563 -0,2080

0.0359 0.0647 -0.0317 -0.2343 -0.4859 -0.6842 2.6980 -0.2359

-0.0468 -0.0687 0.0012 0,0942 -0.0327 -0.1712 -0.1781 0.5121

0.6232 -0.1735 0.0055 -0.0027 0.0006 0.0027 0.0028 -0.0079

-0.1151 0.3570 -0,0268 0.0036 -0.0004 -0.0002 -0.0002 0.0005

-0.0452 -0.1776 0.7016 -0.0407 0.0041 0.0023 0.0026 -0.0070

0.0445 -0.1148 -0,5010 1,2275 -0.0560 0.0302 0.0302 -0.0868

0.0823 -0.0570 -0.2565 -0.8691 1.9168 0,0178 0.0573 -0.1640

0.0699 0.0158 -0.1356 -0.4466 -0.9456 2.5142 0.0566 -0.2086

0,0417 0.0624 -0.0318 -0.2344 -0.4859 -0.6841 2.6981 -0.2363

-0,0545 -0.0657 0.0021 0,0944 -0.0327 -0.1714 -0.1782 0.5127

437

({~

D 2786

TABLE 1 2; 71

Z 69

2; 109

Continued 2; 149

Z 189

2; 229

2; 269

2; 91

C31 Inverse n-Alkanes 0 Ring 1 Ring 2 Ring 3 Ring 4 Ring 5 Ring 6 Ring MA Isoalkanes 0 Ring 1 Ring 2 Ring 3 Ring 4 Ring 5 Ring 6 Ring MA

0.5434 -0.1461 0.0097 -0.0020 0.0003 0.0007 0.0007 -0,0021

-0.1086 0.3529 -0.0334 0.0044 -0.0004 0.0002 0.0002 -0.0005

-0.0446 -0.1757 0.6937 -0.0471 0,0048 0.0022 0.0023 -0.0068

0.0411 -0.1134 -0.4895 1,2055 -0.0583 0,0292 0.0287 -0.0837

0.0749 -0.0529 -0.2463 -0.8440 1.8512 0.0144 0.0535 -0.1550

0.0637 0.0178 -0.1371 -0.4316 -0.8912 2.3848 0.0496 -0.1893

0.0375 0.0601 -0.0348 -0.2258 -0.4645 -0.6487 2.5297 -0.2155

-0.0488 -0.0784 0.0030 0.0990 -0.0413 -0.1741 -0.1794 0.5223

0.6286 -0.1788 0,0081 -0,0035 0.0009 0.0031 0.0031 -0.0092

-0.1256 0.3594 -0.0331 0.0047 -0.0005 -0.0003 -0.0003 0.0010

-0.0515 -0,1731 0.6938 -0.0471 0.0047 0.0020 0.0021 -0.0062

0.0475 -0.1160 -0.4896 1,2054 -0.0582 0.0294 0,0289 -0.0843

0.0867 -0.0573 -0.2464 -0.8442 1.8512 0.0147 0.0538 -0.1559

0.0737 0,0138 -0.1374 -0.4318 -0.8912 2.3851 0.0499 -0.1901

0.0434 0.0579 -0.0370 -0.2260 -0.4645 -0.6465 2.5299 -0,2160

-0.0584 -0.0755 0.0033 0.0990 -0.0413 -0.1743 -0.1798 0.5230

C32 Inverse

n-AIkanes 0 Rm9 1 Ring 2 Ring 3 Ring 4 Ring 5 Ring 6 Ring MA Isoalkanes 0 Ring 1 Ring 2 Ring 3 Ring 4 Ring 5 Ring 6 Ring MA

0.5524 -0.1527 0.0130 -0.0026 0.0004 0.0008 0.0008 -0.0023

-0.1199 0.3568 -0.0409 0.0056 -0.0005 0.0001 0.0001 -0.0003

-0.0522 -0.1724 0.6907 -0.0523 0.0053 0.0019 0.0020 -0.0058

0.0451 -0.1132 -0.4755 1.1703 -0.0594 0.0282 0.0267 -0.0797

0.0830 -0.0567 -0.2442 -0.8144 1.7832 0.0106 0.0487 -0.1444

0.0690 0.0145 -0.1333 -0.4180 -0.8458 2.2659 0.0443 -0.1774

0.0393 0.0576 -0.0390 -0.2142 -0.4427 -0.6013 2.3575 -0.1926

-0.0513 -0.0886 0.0050 0.1027 -0.0494 -0.1790 -0.1786 0.5328

0.6349 -0.1841 0.0119 -0.0042 0.0012 0.0035 0.0035 -0.0105

-0.1378 0.3636 -0.0405 0.0060 -0.0007 -0.0005 -0.0005 0.0015

-0.0600 -0.1694 0.6908 -0.0521 0.0053 0.0016 0.0018 -0.0050

0.0519 -0.1158 -0.4756 1.1702 -0.0594 0.0284 0.0269 -0.0803

0.0954 -0.0615 -0.2444 -0.8114 1.7833 0.0110 0.0491 -0.1457

0.0793 0.0106 -0.1335 -0.4183 -0.8457 2.2663 0.0447 -0.1785

0.0451 0.0553 -0.0414 -0.2144 -0.4426 -0.6011 2.3577 -0.1932

-0.0590 -0.0856 0.0051 0.1029 -0.0495 -0.1792 -0.1789 0.5336

TABLE 2

0 Ring 1 Ring 2 Ring 3 Ring 4 Ring 5 Ring 6 Ring

Precision Summary Based on Cooperative Data Volume Percent

O'r

O'R

r

R

10.5 17.3 15.8 16.7 30.1 6.8 2.8

0.5 0.5 0.2 0.2 0.6 0.3 0.2

1.6 1.5 1.5 1.0 3.4 1.3 1.1

1.5 1.8 0.5 0.8 2.0 0.9 0.7

5.4 5.0 4.9 3.2 11.0 4.3 3.5

c,, = repeatability standard deviation. ~R = reproducibility standard deviation. r = repeatability. R = reproducibility.

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103.

438

<8Tt

Designation: D 2878 - 95

An American National Standard

Standard Test Method for Estimating Apparent Vapor Pressures and Molecular Weights of Lubricating Oils 1 This standard is issued under the fixed designation D 2878; the number immediately following the designation indicates the year of original adoption or, in the ease of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (~) indicates an editorial change since the last revision or reapproval.

E 1 Specification for ASTM Thermometers 6 E 659 Test Method for Autoignition Temperature of Liquid Chemicals 7

1. Scope I. 1 This test method provides a calculation procedure for converting data obtained by Test Method D 972, to apparent vapor pressures and molecular weights. It has been demonstrated to be applicable to petroleum based and synthetic ester lubricating oils, 2 at temperatures of 395 to 535 K (250 to 500*F). However, its applicability to lubricating greases has not been established.

3. Terminology

3.1 Descriptions of Terms Specific to This Standard: 3.1.I apparent vapor pressure (p), n - - t h e time-averaged value of the vapor pressure from the start to the end of the evaporation test. DISCUSSION--Whilethis may include some effects of differences in nonideality of the vapor, heat of vaporization, surface tension and viscosity between the m-terphenyl and the lubricating oil, these factors have been demonstrated to be negligible.7 Unless stated, this average shall cover the range 0 to 5 -4- 1%.

NOTE 1 - - M o s t lubricants boil over a fairly wide temperature range, a fact recognized in discussion of their vapor pressures. For example, the apparent vapor pressure over the range 0 to 0. 1% evaporated may be as much as 100 times that over the range 4.9 to 5.0 % evaporated. 3

1.2 The values stated in SI units are to be regarded as the standard. In cases where materials, products, or equipment are available in inch-pound units only, SI units are omitted. 1.3 This standard does' not purport to address all of the

3.1.2 cell constant (k), n--the ratio of the amount of m-terphenyl or lubricating oil carried off per unit volume of gas to that predicted by Dalton's law.

safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability or regulatory limitations prior to use. For specific

k = 22.41 P W / V p M

(1)

where: k = call constant P = ambient atmospheric pressure, torr W = mass of lubricant evaporated, g V = volume of gas passed through all litres at 273"K and 101.3 kPa (760 tort) p = apparent vapor pressure, torr M = mole average molecular weight of lubricant vapor, g/mole T = test temperature, K It has been empirically determined that for m-terphenyl in air

hazard statements, see Notes 3, 5, and 6.

2. Referenced Documents

2.1 A S T M Standards: A 240 Specification for Heat-Resisting Chromium and Chromium-Nickel Stainless Steel Plate, Sheet, and Strip for Pressure Vessels 3 D 92 Test Method for Flash and Fire Points by Cleveland Open Cup 4 D 972 Test Method for Evaporation Loss of Lubricating Greases and Oils 4 D2503 Test Method for Molecular Weight (Relative Molecular Mass) of Hydrocarbons by Thermoelectric Measurement of Vapor Pressure 4 D 2595 Test Method for Evaporation Loss of Lubricating Greases over Wide-Temperature Range 4 D 2883 Test Method for Reaction Threshold Temperature of Liquid and Solid Materials 5

k = 0.1266 - 12.60/( T - 273)

(2)

and that the cell constant is independent of the composition of the lubricant. 7 3.1.2.1 Test Method D 972 is normally run with air, which may cause changes in easily oxidized fluids. In such cases, use of c o m m o n reactive gas nitrogen and recalibration to obtain a slightly different cell constant ( k ' ) is mandatory.

4. Summary of Test Method 4.1 The test is run at the selected temperature for a sufficient time to give the selected amount of evaporation, which is 5 ___ 1% unless otherwise specified. This evaporation rate is compared with a standard value for pure m-terphenyl to yield the apparent vapor pressure and molecular weight of the lubricating oil as defined in Section 3.

This test method is under the jurisdiction of Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.11 on Engineering Sciences of High Performance Fluids and Sohds. Current edition approved Jan. 15, 1995. Published March 1995. Originally published as D 2878 - 70. Last previous edition D 2878 - 93. 2 Coburn, J. F., "Lubricant Vapor Pressure Derived from Evaporation Loss," Transactions, Am. Soc. Lubricating Engrs., ASLTA, Vol 12, 1969, pp. 129-134. 3 Annual Book of ASTM Standards, Vol 01.03. 4 Annual Book of ASTM Standards, Vol 05.01. 5 Annual Book of ASTM Standards, Vol 05.02.

6 Annual Book of ASTM Standards, Vol 14.03. 7 Annual Book of ASTM Standards, Vol 14.02.

439

(~') D 2878 5. Significance and Use 5.1 The vapor pressure of a substance as determined by measurement of evaporation reflects a property of the bulk sample. Little weight is given by the procedure to the presence of low concentrations of volatile impurities. 5.2 Vapor pressure, per se, is a thermodynamic property that is dependent only upon composition and temperature for stable systems. In the present method composition changes occur during the course of the test so that the contribution of minor amounts of volatile impurities is minimized.

three knurled cover-tightening screws securely to prevent air leakage under the cover. Pass clean air through the cell for the required period. NOTE 4: Warning--Do not perform this test with air at temperatures in exces of the autoignition temperature of the test specimen as determined by Test Method E 659 or Test Method D 2883, or both. 7.3 At the end of the test period, remove the assembled test specimen cup and hood from the cell, and allow to cool to room temperature. Determine the net weight of the sample to the nearest 1 mg.

8. Calibration of Equipment 8.1 It is assumed that equipment conforming to Test Method D 972 in design and installation needs no calibration. If questions arise, carry out the procedure using m-terphenyl (WarningmSee Note 5) of good commercial quality. 9 The following two points shall be determined:

6. Apparatus

6.1 Evaporation Cell, as described in Annex A 1. 6.2 Air Supply System, capable of supplying to the cell the required flow of air free of entrained particles (Warning--See Note 2). A 410 mm (16-in.) length of 1 in. diameter pipe packed with glass wool has been found satisfactory for filtering the air. NOTE 2: Warning--Compressed gas under high pressure. Use with

extreme caution in the presence of combustible material, since the autoignition temperatures of most organic compounds in air are drastically reduced at elevated pressures. See Annex A2. I. 6.3 Oil Bath, as described in Annex A1. NOTE 3--Other constant-temperature baths may be used if the exit air passing over the grease sample is at the test temperature (+0.5 K (I'F)). 6.4 ThermometersuASTM Thermometers graduated in either Celsius or Fahrenheit degrees and having a range from - 5 to 400"C (20 to 760"F) and conforming to the requirements for Thermometers 3C or 3F respectively as described in Specification E 1. 6.5 FlowmeterSmA rotameter calibrated to deliver air at a rate of 2.583 + 0.02 g/min between 289 and 302 K (60 and 85"F) (2 L/min at standard temperature and pressure). It shall be furnished with a needle valve and mounted as shown in Fig. 1. 6.6 Oil Sample Cup, as described in Fig. 4 and A 1.1.2.

K 395 420

Temperature *F 250 300

Time, h 22 6.5

Evaporation to Conform to Eq 2, g 0.267 ± 0.027 0.503 + 0.050

If the data do not fall within the above ranges, check flow rate and temperature. If these are correct, prepare a substitute equation for k ' similar to Eq 2 and use it in Section 10. When use of non-reactive gas is required this calibration is necessary as standard cell constants are not valid for gases other than air. NOTE 5: Warning--Harmful or fatal if swallowed. See Annex A2.2.

8.2 If the apparatus specified in Test Method D 2595 is to be used, it shall be calibrated as described in 8.1.

9. Determination of Molecular Weight and Apparent Vapor Pressure 9.1 If a value of M is already available from Test Method D2503 or equivalent, 9.2 through 9.4 and 10.1 may be omitted, even though this value is for the whole lubricant instead of the part vaporized, as the calculation is not very sensitive to M error. 9.2 Conduct a test on the sample in accordance with the procedure in Section 7, at 477 K (400°F). The proper test time to evaporate 5 % (0.500 g) may be estimated from the flash point of the lubricant as measured by Test Method D 92, from Table 1.

7. Procedure 7.1 Weigh the clean test specimen cup and hood to the nearest 1 rag. Transfer, by means of a pipet, 10.00 _+ 0.05 g of test specimen to the cup. Assemble the cup and hood, being careful not to splash oil on the underside of the hood. Weigh the assembly and record the net test specimen weight to the nearest 1 mg. 7.2 With cover in place, but without the hood and test specimen cup attached, allow the evaporation cell to acquire the temperature of the bath (controlled to _+0.5 K (_+I°F)) at which the test is to be made by immersing the cell in it, as shown in Fig. 1. Allow the cell to remain in the bath at least 1/2h before beginning the test. During this period, allow clean air (Warning--See Note 2) to flow through the cell at the prescribed rate, 2.583 ___ 0.02 g/min (2 L/min at standard temperature and pressure), as indicated by the rotameter. Then remove the cover, thread and weighed hood and sample cup into place, and replace the cover. Tighten the

9.3 For synthetic and redistilled petroleum oils, the variation of W/t with Wis not great and the 5 % point shall be approximated by linear interpolation of two points taken at different W values. For single-distilled petroleum or unknown oils, three points shall be plotted, representing the estimated time and also half and twice that time. These readings may all be obtained on one sample by stop and start operation of the apparatus. 9.4 When a single data point which does not fall within the 5 + 1% evaporated range is used (as is often justifiable

a The Flowrater meter manufactured by Fisher and Porter Co., Hatboro, PA, has been found satisfactory.

9 Santowax, M., Monsanto Chemical Co., St. Louis, MO, has proved satisfactory.

NOTE 6 - - T h e need for a run at 477 K (400*F) is, created by lack of exact values for the first two constants in Eqs 4, 5, and 6 for other temperatures.

440

1@) D 2878 AIR OUTLET GROOVED COVER

T

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,EVE.,:

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¢

/ • i~O '4'I J¢)

2;'.

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0.052

.C

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'

';

:

c :

ROTOMETER j

AIR ADJUSTMENT

i ,.

'.-I~

t

~ c

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i

I / 8 " HOLE

--,,a

\

CROSS SECTION SUPPORT ROD BATH WALL

AIR INLET I/4" O.D. TUBING MINIMUM LENGTH 7 2 " (APPROXIMATELY 7 T U R N S ) - - - - ~ COVER TfGHTENING

X

c

HO00

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.057"

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I 2,161'* 2.151"

1 t6 ",~

;I,

f[

,

~ - SAId/q.E CUP

FRONT VIEW ALL DIMENSIONS-~1,/64' UNLESS OTHERWISE SPECIFIED

FIG. 1

Evaporation Test Cell

10.1.2 Calculate the molecular weights of lubricants in general as follows:

on synthetic oils) or the evaporation is measured at some other level of IV, this fact shall be reported in Section 1 I. 9.5 The test for apparent vapor pressure is conducted in accordance with Section 7 for the estimated time at the selected temperature. If the 5 + 1% criterion is not met, proceed as in 9.3.

log M = 3.028 - 0.164 log(10 335 PW/t)

(4)

10.1.3 For lubricants of known composition, slightly greater accuracy is obtained with special equations: 10.1.3.1 For polyol esters: l o g M = 3.181 - 0.207 log(10 335 PW/t) (5)

10. C a l c u l a t i o n s

10.1 Calculation of Molecular Weight: 10.1.1 Use the evaporation time, t, (in seconds) obtained in 9.3 to evaporate 5 + 1%.

10.1.3.2 For dibasic esters: log M = 3.089 - 0.190 log(10 335 PW/t) 441

(6)

(@) D 2878 TABLE 1

E s t i m a t e d Time t o E v a p o r a t e 5 %, h A

Flash Point

Test Temperature, K (*F)

K

°F

394 (250)

422 (300)

450 (350)

477 (400)

422 450 477 505 533 561 589

300 350 400 450 500

2.7 8.1 24.3 72.9 ...

0.9 2.7 8.1 24.3 72.9

0.3 0.9 2.7 8.1 24.3 72.9

0.1 0.3 0.9 2.7 8.1 24.3 72.9

550

.

.

600

.

.

. .

.

.

.

.

. .

.

.

.

505

(450)

... 0.1 0.3 0.9 2.7 8.1 24.3

533 (500) ... 01; 0.3 0.9 2.7 8.1

A This table may be extended by means of equation: Estimated Hours = 0,9 log -1 [0.0095(F - 1.8 T + 460)]

10.1.3.3 For mineral oils: log M = 2.848 - 0.106 log(10 335 PW/t)

(7)

10.1.4 The molecular weight equations all contain the standard value of k at 477 K (400*F) from Table 2. If a change greater than +3 % in this value is caused by the calibration in Section 8, adjustments shall be made in the constant 10 335 by multiplying it by the factor (k/k'). 10.2 Calculation of Apparent Vapor Pressure: 10.2.1 Use the molecular weight, M, as calculated in 10.1 or predetermined in 9.1 to calculate the vapor pressure as follows: p = 672 ew/tkM (8) where k is obtained from Table 2. Use Eq 2 to extend this table. If a special equation was required in 8. I, use it rather than Table 2 or Eq 2. 10.2.2 For the special case of lubricants run at 477 K (400*F) for 6.5 h as required in several military aircraft engine oil specifications, with P = 760 torr: logp = 1.164 log(10W)- 1.255 (9) where l0 I,V = percent evaporated from a 10-g sample. 10.2.3 These results may be converted to SI units by the equations p' = 133.32p and P ' = 133.32P (10) where: p' = apparent vapor pressure, Pa P' = ambient atmospheric pressure, Pa 11. R e p o r t 11.1 If the results are obtained in accordance with 9.1, 9.2, 9.3, and 9.5, and calculated by Eq 4, they shall be reported as "Apparent Vapor Pressure = torr at _ _ * C ( _ _ *F), and Molecular Weight = _ _ ." I 1.2 If the results are obtained in accordance with 9.1, 9.2, 9.3, and 9.5, and calculated by Eq 5, 6, or 7, they shall be reported as "Apparent Vapor Pressure = _ _ torr at _ _ * C ( _ _ *F), and Molecular Weight = _ _, calculated as TABLE 2

K

*F

394 422 450 477 505 533

250 300 350 400 450 500

polyol ester," "...diester," or "...petroleum," as appropriate. 11.3 If the results are obtained as indicated in 9.4 or Note 4, they shall be reported as "Apparent Vapor Pressure = _ _ ton" at _ _ * C ( _ _ *F) and 0 to _ _ percent evaporated." The molecular weight shall be reported only if the test was conducted at 477 K (400*F) or a separate test at this temperature was made. 12. P r e c i s i o n 12.1 No independent precision statement can be issued at this time. However, the statement in Test Method D 972 may be used as a guide. Applying the exponent 1.164 from Coburn's paper 2 to the Test Method D 972 statement results in the following criteria for apparent vapor pressure results: 12.1.1 RepeatabilitymThe difference between two test results, obtained by the same operator with the same apparatus under constant operating conditions on identical test material, would in the long run, in the normal and correct operation of the test method, exceed the following values only in one case in twenty: 6%

12.1.2 Reproducibility--The difference between two single and independent results obtained by different operators working in different laboratories on identical test material would, in the long run, in the normal and correct operation of the test method, exceed the following values only in one case in twenty: 23 %

12.2 Similarly, from Test Method D 2595, for use with that apparatus: 12.2.1 Repeatability--The difference between two test results, obtained by the same operator with the same apparatus under constant operating conditions on identical test material, would in the long run, in the normal and correct operation of the test method, exceed the following values only in one case in twenty: 23 %

Standard Cell Constants

Temperature

(3)

12.2.2 Reproducibility--The difference between two single and independent results obtained by different operators working in different laboratories on identical test material would, in the long run, in the normal and correct operation of the test method, exceed the following values only in one case in twenty:

Cell Constant2 0.02247 0.04204 0.05540 0.06483 0.07229 0,07814

35 % 442

~

D 2878

12.3 Bias--No statement is made on bias for this test method since the results cannot be compared to an accepted reference material.

13. Keywords 13.1 lubricating oils; molecular weight; vapor pressure

ANNEXES

(Mandatory Information) A1. APPARATUS A 1.1 Evaporation Cell and attachments conforming with the dimensional tolerances indicated in Fig. 1 and capable of being supported upright in the oil bath. Other structural details are as follows: A 1.1.1 The body and cover of the cell shall be constructed of stainless steel and the air-heating coil of tinned copper tubing. A1.1.2 The sample cups (recommended maximum weight 200 g each), hood, eduction tube, and orifice shall be constructed of 18 % chromium, 8 % nickel alloy steel. A suitable material is an alloy steel conforming to Grade S, Type 304, of Specifications A 240. To facilitate removal and separation of the cup and hood for inserting the sample and weighing, the sample cup shall be threaded to the hood and

this in turn to the eduction tube of the cover. A 1.1.3 The cover of the cell shall be made airtight. A 1.2 Oil Bath of sufficient depth to allow submersion of the evaporation cell to the proper level and capable of being controlled at the desired test temperature +0.5 K, (___I'F), with a maximum variation throughout the bath of 0.5 K (I'F). Circulation of the oil heating medium by a pump or stirrer is recommended. Sufficient heat capacity shall be provided to return the bath to the required temperature within 60 min after immersion of the cell. The bath shall be provided with a temperature well such that the thermometer used can be inserted to its proper immersion depth. The bath shall be arranged so that there are no drafts or wide fluctuations in temperature around the evaporation cell.

A2. PRECAUTIONARY STATEMENTS

A2.1 Compressed Air

Make sure cylinder is supported at all times. Stand away from cylinder outlet when opening cylinder valve. Keep cylinder out of sun and away from heat. Keep cylinders from corrosive environment. Do not use cylinder without label. Do not use dented or damaged cylinders. For technical use only. Do not use for inhalation purposes.

WarningmCompressed gas under high pressure. Use with extreme caution in the presence of combustible material, since the autoignition temperatures of most organic compounds in air are drastically reduced at elevated pressures. Keep cylinder valve closed when not in use. Always use a pressure regulator. Release regulator tension before opening cylinder. Do not transfer to cylinder other than one in which air is received. Do not mix gases in cylinder. Do not drop cylinder.

A2.2 m-Terphenyl Warning--Harmful or fatal if swallowed. Use only with adequate ventilation. Avoid prolonged breathing of vapor or spray mist. Avoid prolonged repeated contact with skin.

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend, if you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103.

443

(~)

Designation: D 2887 - 97

Standard Test Method for Boiling Range Distribution of Petroleum Fractions by Gas Chromatography I This standard is issued under the fixed designation D 2887; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last vcapproval. A superscript epsilon (~) indicates an editorial change since the last revision or reapproval.

This test method has been approved for use by agencies of the Department of Defense. Consult the DoD Index of Specifications and Standards for the specific year of issue which has been adopted by the Department of Defense.

1. Scope 1.1 This test method covers the determination of the boiling range distribution of petroleum products. The test method is applicable to petroleum products and fractions having a final boiling point of 538"C (1000*F) or lower at atmospheric pressure as measured by this test method. This test method is limited to samples having a boiling range greater than 55"C (100*F), and having a vapor pressure sufficiently low to permit sampling at ambient temperature. 1.2 This test method is not to be used for the analysis of gasoline samples or gasoline components. These types of samples must be analyzed by Test Method D 3710. 1.3 The values stated in SI units are to be regarded as standard. The inch-pound units given in parentheses are for information only. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 2. Referenced Documents

2. I ASTM Standards: D 86 Test Method for Distillation of Petroleum Products2 D 1160 Test Method for Distillation of Petroleum Products at Reduced Pressure 2 D 2892 Test Method for Distillation of Crude Petroleum (15-Theoretical Plate Column) 3 D3710 Test Method for Boiling Range Distribution of Gasoline and Gasoline Fractions by Gas Chromatography 3 D 4057 Practice for Manual Sampling of Petroleum and Petroleum Products 3 D 4626 Practice for Calculation of Gas Chromatographic Response Factors 3 E 260 Practice for Packed Column Gas Chromatography 4 E 355 Practice for Gas Chromatography Terms and Relationships 4 Tl~s test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.04 on Hydrocarbon Analysis. Current edition approved Apr. 10, 1997. Published October 1997. Originally published as D 2887 - 73, Last previous edition D 2887 - 93. ~t 2 Annual Book ofASTMStandards, Vol 05.01. 3 Annual Book of ASTM Standards, Vol 05.02. 4 Annual Book of ASTM Standards, Vol 14.02.

444

E 516 Practice for Testing Thermal Conductivity Detectors Used in Gas Chromatography 4 E 594 Practice for Testing Flame Ionization Detectors Used in Gas or Supercritical Fluid Chromatography 4 3. Terminology 3.1 Definitions: 3.1.1 This test method makes reference to many common gas chromatographic procedures, terms, and relationships. Detailed definitions of these can be found in Practices E 260, E 355, and E 594. 3.2 Definitions of Terms Specific to This Standard: 3.2.1 area slice--the area, resulting from the integration of the chromatographic detector signal, within a specified retention time interval. In area slice mode (see 6.3.2), peak detection parameters are bypassed and the detector signal integral is recorded as area slices of consecutive, fixed duration time intervals. 3.2.2 corrected area sliceman area slice corrected for baseline offset, by subtraction of the exactly corresponding area slice in a previously recorded blank (non-sample) analysis. 3.2.3 cumulative corrected areamthe accumulated sum of corrected area slices from the beginning of the analysis through a given retention time, ignoring any non-sample area (for example, solvent). 3.2.4 initial boiling point (IBP)--the temperature (corresponding to the retention time) at which a cumulative corrected area count equal to 0.5 % of the total sample area under the chromatogram is obtained. 3.2.5 final boiling point (FBP)--the temperature (corresponding to the retention time) at which a cumulative corrected area count equal to 99.5 % of the total sample area under the chromatogram is obtained. 3.2.6 slice ratemthe time interval used to integrate the continuous (analog) chromatographic detector response during an analysis. The slice rate is expressed in hertz (for example, integrations or slices per second). 3.2.7 slice time--the time associated with the end of each contiguous area slice. The slice time is equal to the slice number divided by the slice rate. 3.2.8 total sample areamthe cumulative corrected area, from the initial area point to the final area point, where the chromatographic signal is considered to have returned to baseline after complete sample elution. 3.3 Abbreviations: 3.3.1 A common abbreviation of hydrocarbon corn-

(~ D 2887 of at least 1 min for the initial boiling point and to elute compounds up to a boiling temperature of 538"C (1000*F) before reaching the upper end of the temperature program. The programming rate must be sufficiently reproducible to obtain retention time repeatability of 0.1 min (6 s) for each component in the calibration mixture described in 8.8. 6.1.3 Cryogenic Column Cooling--Column starting temperatures below ambient will be required if samples with initial boiling points of less than 93"C (200*F) are to be analyzed. This is typically provided by adding a source of either liquid carbon dioxide or liquid nitrogen, controlled through the oven temperature circuitry. Excessively low initial column temperature must be avoided to ensure that the stationary phase remains liquid. The initial temperature of the column should be only low enough to obtain a calibration curve meeting the specifications of the method. 6.1.4 Sample Inlet System--The sample inlet system must be capable of operating continuously at a temperature equivalent to the maximum column temperature employed, or provide for on-column injection with some means of programming the entire column, including the point of sample introduction, up to the maximum temperature required. Connection of the column to the sample inlet system must be such that no temperature below the column temperature exists. 6.1.5 Flow ControllersmThe gas chromatograph must be equipped with mass flow controllers capable of maintaining carrier gas flow constant to + 1% over the full operating temperature range of the column. The inlet pressure of the carder gas supplied to the gas chromatograph must be sufficiently high to compensate for the increase in column backpressure as the column temperature is raised. An inlet pressure of 550 kPa (80 psig) has been found satisfactory with columns described in Table 1. 6.1.6 Microsyringe--A microsyringe is needed for sample introduction.

pounds is to designate the number of carbon atoms in the compound. A prefix is used to indicate the carbon chain form, while a subscripted suffix denotes the number of carbon atoms (for example, normal decane = n-C~o; isotetradecane = i-Cz4). 4. Summary of Test Method 4.1 The boiling range distribution determination by distillation is simulated by the use of gas chromatography. A nonpolar packed or open tubular (capillary) gas chromatographic column is used to elute the hydrocarbon components of the sample in order of increasing boiling point. The column temperature is raised at a reproducible linear rate and the area under the chromatogram is recorded throughout the analysis. Boiling points are assigned to the time axis from a calibration curve obtained under the same chromatographic conditions by analyzing a known mixture of hydrocarbons covering the boiling range expected in the sample. From these data, the boiling range distribution can be obtained.

5. Significance and Use 5.1 The boiling range distribution of petroleum fractions provides an insight into the composition of feedstocks and products related to petroleum refining processes. The gas chromatographic simulation of this determination can be used to replace conventional distillation methods for control of refining operations. This test method can be used for product specification testing with the mutual agreement of interested parties. 5.2 Boiling range distributions obtained by this test method are essentially equivalent to those obtained by true boiling point (TBP) distillation (see Test Method D 2892). They are not equivalent to results from low efficiency distillations such as those obtained with Test Method D 86 or Test Method D 1160. 6. Apparatus

6.1 Chromatograph--The gas chromatograph used must have the following performance characteristics: 6.1.1 Detector--Either a flame ionization or a thermal conductivity detector may be used. The detector must have sufficient sensitivity to detect 1.0 % dodecane with a peak height of at least l0 % of full scale on the recorder under conditions prescribed in this method and without loss of resolution as defined in 8.3.1. When operating at this sensitivity level, detector stability must be such that a baseline drift of not more than 1% of full scale per hour is obtained. The detector must be capable of operating continuously at a temperature equivalent to the maximum column temperature employed. Connection of the column to the detector must be such that no temperature below the column temperature exists. NOTE l--It is not desirable to operate a thermal conductivity detector at a temperature higher than the maximum column temperature employed.Operation at higher temperature generallycontributes to higher noise levels and greater drift and can shorten the useful life of the detector. 6.1.2 Column TemperatureProgrammer--The chromatograph must be capable of linear programmed temperature operation over a range sufficient to establish a retention time 445

NOTE 2--Automatic sampling devices or other sampling means, such as indium encapsulation,can be used provided: the system can be operated at a temperature sufficiently high to completely vaporize hydrocarbons with atmosplaedcboiling points of 538"C (1000*F), and the sampling system is connected to the chromatographic column avoiding any cold temperature zones. 6.2 Column--Any column and conditions may be used that provide separation of typical petroleum hydrocarbons in order of increasing boiling point and meet the column performance requirements of 9.3.1 and 9.3.3. Successfully used columns and conditions are given in Table I. 6.3 Data Acquisition System: 6.3.1 Recorder--A 0 to 1 mV range recording potentiometer or equivalent, with a full-scale response time of 2 s or less may be used. 6.3.2 Integrator--Means must be provided for determining the accumulated area under the chromatogram. This can be done by means of an electronic integrator or computer based chromatography data system. The integrator/computer system must have normal chromatographic software for measuring the retention time and areas of eluting peaks (peak detection mode). In addition, the system must be capable of converting the continuously integrated detector signal into area slices of fixed duration. These contiguous area slices, collected for the entire analysis, are

t@) D 2 8 8 7 TABLE 1 Packed Columns

Typical Operating Conditions

1

2

3

4

Column length, m (ft) Column outside diameter, mm (in.) Liquid phase Percent liquid phase

1.2 (4) 6.4 (1/4)

1.5 (S) 3.2 (I/8)

0.S (1 .S) 3.2 (1/8)

0.6 (2) 6.4 (1/8)

Column length (m) Column Inner diameter (ram)

Open Tabular ~

7.5 0.53

5 0.53

10 0.53

OV-1 3

SE-30 5

UC.W98 10

SE,-30 10

Stationa~j phase Statiomlry phase ttt:kneas

DB-1 1.5

HP-1

HP-1

0.88

2.e5

Support matedal Support mesh size Initial column temperature, °C Final column temperature, °C Programming rate, °C/min Carrier gas Carrier gas flow, mL./mln Detector Detector temperature, °C Injection port temperature, °C Sample size, it

SA 60/80 -20 360 10 helium 40 TC 360 360 4

Ge 60/80 -40 350 6.5 helium 30 FID 370 370 0.3

pc 801100 -30 360 10 N= 25 FID 360 350 1

pc 60/80 -50 390 7.5 helium 60 TC 390 390 5

nrm>gen

he,am

begum

30 40 340 10 FID 350 340 0.5 25

12 3,5 350 10 FID 380 ¢ooi on.column 1 2

12 65 350 20 FID 370 cool on-colunm 0.1-0.2 neat

(m) Cardergas Cardergas flow rate, ml./mln Initial column Wmperature, °C Final column tempefatum, *C Programming fate, "Clmln Detector Detector temperature, °C Injector temperature, °C Sample size, pL Sample concentration mass ~,

5

6

7

Dlatolxxt S: silane treated, a ChromosodoG (AW-DMS), c Chromosorb P, acid washed.

NOTE 4: WaralagmHelium and nitrogen are compressedgasesunder high pressure.

stored for later processing. The electronic range of the integrator/computer (for example, 1 V, 10 V) must be within the linear range of the detector/electrometer system used. The system must be capable of subtracting the area slice of a blank run from the corresponding area slice of a sample run.

7.5 Hydrogen--Hydrogen of high purity (for example, hydrocarbon free) is used as fuel for the flame ionization detector (FID). (Warning--See Note 5.)

NOTe 3--some gas chromatographs have an algorithm built into their operating software that allows a mathematical model of the baseline profile to be stored in memory. This profile is automatically subtracted from the detector signal on subsequent sample analyses to compensate for any baseline offset.Some integration systemsalso store and automaticallysubtract a blank analysis from subsequent analytical determinations.

7.6 Air--High purity (for example, hydrocarbon free) compressed air is used as the oxidant for the flame ionization detector (FID). (Warning--See Note 6.)

7. Reagents and Materials

NOTE 6: Warnlne--Compressedair is a gas under high pressure and supports combustion.

7.1 Purity of Reagents--Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society where such specifications are available. 5 Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination. 7.2 Liquid Phasefor Columns--Methyl silicone gums and liquids provide the proper chromatographic hydrocarbon elution characteristics for this test method. 7.3 Solid Support for Packed Columns--Chromatographic grade diatomateous earth solid support material within a particle size range of 60 to 100 sieve mesh size is recommended. 7.4 Carrier Gas--Helium or nitrogen of high purity. (Warning--See Note 4.) Additional purification is recommended by the use of molecular sieves or other suitable agents to remove water, oxygen, and hydrocarbons. Available pressure must be sufficient to ensure a constant carrier gas flow rate (see 6.1.5).

NOTE 5: WarninemHydrogen is an extremely flammablegas under high pressure.

7.7 Column Resolution Test Mixture--A mixture of 1% each of n-Cm6 and n-Cms paraffin in a suitable solvent, such as n-octane, for use in testing the column resolution. (Warning--See Note 7.) Non 7: Warningmn-octaneis flammableand harmful ffinhaled. 7.8 Calibration Mixture--An accurately weighed mixture of approximately equal mass quantifies of n-hydrocarbons including n-C5 to n-C44 in carbon disulfide (CS2). (Warning--See Note 8.) At least one compound in the mixture must have a boiling point lower than the initial boiling point of the sample. Boiling points of n-paraffins are listed in Table 2. 7.8.1 Packed Columns--The final concentration should be approximately ten parts of the n-paraffin mixture to one hundred parts of CS2. 7.8.2 Open Tubular Columns--The final concentration should be approximately one part of the n-paraffin mixture to one hundred parts of CS2. NOTE 8: Wamlag--Catrbon disulfide is extremely volatile, flammable, and toxic.

s Reagent Chemicals, American Chemical Society Specifications, American

7.9 Reference Gas Oil No. I--A reference sample, that has been analyzed by laboratories participating in the test method cooperative study. Consensus values for the boiling range distribution of this sample are given in Table 3.

Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed by the American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.IC, and the United States Pharmacopeia and National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville, MD.

446

lip D 2887 TABLE 2

Boiling Points of Normal Paraffins 'q

Carbon Number

Boiling Point,°C

Boiling Point,°F

Carbon Number

Boiling Point,*C

Boiling Point,OF

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22

-162 -89 -42 0 36 69 98 126 151 174 196 216 235 254 271 287 302 316 330 344 356 369

-259 -128 -44 32 97 156 208 259 304 345 385 421 455 489 520 549 576 601 626 651 674 695

23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44

380 391 402 412 422 431 440 449 458 466 474 481 489 496 503 509 516 522 528 534 540 545

716 736 756 774 792 808 825 840 856 871 885 898 912 925 937 948 961 972 982 993 1004 1013

A API Project 44, October 31, 1972.

8. Sampling 8.1 Samples to be analyzed by this test method must be obtained using the procedures outlined in Practice D 4057. 8.2 The test specimen to be analyzed must be homogeneous and free of dust or undissolved material.

9. Preparation of Apparatus 9.1 Chromatograph--Place in service in accordance with the manufacturer's instructions. Typical operating conditions are shown in Table 1. 9.1.1 When a flame ionization detector is used, regularly remove the deposits formed in the detector from combustion of the silicone liquid phase decomposition products. These deposits will change the response characteristics of the detector. 9.1.2 If the sample inlet system is heated above 300"C (572"F), a blank analysis must be made after a new septum is installed to ensure that no extraneous detector response is produced by septum bleed. At the sensitivity levels commonly employed in this method, conditioning of the septum at the operating temperature of the sample inlet system for several hours will minimize this problem. A recommended practice is to change the septum at the end of a series of analyses rather than at the beginning of the series. 9.2 Column Preparation: 9.2.1 Packed Columns--Any satisfactory method that will produce a column meeting the requirements of 9.3.1 and 9.3.3 can be used. In general, use liquid phase loadings of 3 to 10 %. Condition the column at the maximum operating temperature to reduce baseline shifts due to bleeding of the column substrate. The column can be conditioned very rapidly and effectively using the following procedure: 9.2.1.1 Connect the column to the inlet but leave the detector end free. 9.2.1.2 Purge the column thoroughly at ambient temperature with carder gas. 9.2.1.3 Turn off the carder gas and allow the column to depressurize completely.

9.2.1.4 Seal off the open end (detector) of the column with an appropriate fitting. 9.2.1.5 Raise the column temperature to the maximum operating temperature. 9.2.1.6 Hold the column at this temperature for at least 1 h with no flow through the column. 9.2.1.7 Cool the column to ambient temperature. 9.2.1.8 Remove the cap from the detector end of the column and turn the carrier gas back on. 9.2.1.9 Program the column temperature up to the maximum several times with normal carder gas flow. Connect the free end of the column to the detector. 9.2.1.10 An alternative method of column conditioning that has been found effective for columns with an initial loading of 10 % liquid phase consists of purging the column with carder gas at the normal flow rate while holding the column at the maximum operating temperature for 12 to 16 h, while detached from the detector. 9.2.2 Open Tubular ColumnsmOpen tubular columns with cross-linked and bonded stationary phases are available from many manufacturers and are usually pre-conditioned. These columns have much lower column bleed than packed columns. Column conditioning is less critical with these columns but some conditioning may be necessary. The column can be conditioned very rapidly and effectively using the following procedure. 9.2.2.1 Once the open tubular column has been properly installed into the gas chromatograph and tested to be leak free, set the column and detector gas flows. Before heating the column, allow the system to purge with carder gas at ambient temperature for at least 30 rain. 9.2.2.2 Increase the oven temperature about 5 to 10*C per minute to the final operating temperature and hold for about 30 rain. 9.2.2.3 Cycle the gas chromatograph several times through its temperature program until a stable baseline is obtained. 9.3 System Performance Specification: 9.3.1 Column Resolution--The column resolution, influenced by both the column physical parameters and operating conditions, affects the overall determination of boiling range distribution. Resolution is therefore specified to maintain equivalence between different systems (laboratories) employing this test method. Resolution is determined using Eq 1 and the C~6 and Cls paraffins from a column resolution test mixture analysis (see 8.8 and Section 10), and is illustrated in Fig. 1. Resolution (R) must be at least three and not more than ten, using the identical conditions employed for sample analyses: R -- 2(t2 - t~)/[l.699(w2 + w0] (1) where: R ~- resolution, t~ = time(s) for the n-Cl6 peak maximum, t2 -- time(s) for the n-C~s peak maximum, wI = peak width(s), at half height, of the n-C16 peak, and w2 - peak width(s), at half height, of the n-C~8 peak. 9.3.2 Detector Response Calibration--This test method assumes that the detector response to petroleum hydrocarbons is proportional to the mass of individual components. This must be verified when the system is put in service, and 447

~)

D 2887

TABLE 3 Test Method D 2887 Reference Gas Oil No. 1'~ BatCh 1 ~Off

Batch 2

Allowable Difference

oC

oF

oc

oF

oc

IBP 5 10 15 20 25 30 35 40 45 50 55 60

114 143 169 196 221

238 289 336 384

13.7 6.8 7.4 8.1 8.7

496

4.7

8.4

287

548

4.3

7.7

312

594

4.3

7.7

332

629

240 304 348 393 435 470 499 527 552 578 594 611 629

7.6 3.8 4.1 4.5 4.9

258

115 151 176 201 224 243 259 275 289 302 312 321 332

4.3

7.7

65

343

343

649

70 75 80 85 90 95 FBP

354 364 376 389 404 425 475

649 669

354 365 378 391 407 428 475

668 690 712 735 764 803 888

4.3

7.7

4.3

7.7

4.3 5.0 11.8

7.7 9.0 21.2

429

688 709 732 759 797 887

•F

A Consensus results for Batch 2 obtained from 30 laboratories in 1995. Supporting data are available from ASTM headquarters. Request RR:D02-1407.

t2, s e c < <

t 1, s e c

e. O 4) "_E

Y2, s e c

Y1,

_¢

/

O.

E

Hexadecane

Octadecane

(n

L

J

O

FIG. 1 ColumnResolution Parametem

in deviations from a true boiling point versus retention time relationship. If stationary phases other than those referenced in 7.1 are used, the retention times of a few alkylbenzenes (for example, o-xylene, n-butyl-benzene, 1,3,5-triisopropylbenzene, n-decyl-benzene, and tetradecylbenzene) across the boiling range should be analyzed to make certain that the column is separating in accordance with the boiling point order (see Appendix X 1).

whenever any changes are made to the system or operational parameters. Analyze the calibration mixture (see 8.8) using the identical procedure to be used for the analysis of samples (see Section 10). Calculate the relative response factor for each n-paraffin (relative to n-decane) in accordance with Practice D 4626 and Eq 2: F n ~. (Mn/An)/(Mto/Aio) (2) where: F . = relative response factor, M. = mass of the n-paraffin in the mixture, A. = peak area of the n-paraffin in the mixture, M,o = mass of the n-decane in the mixture, and A,o = peak area of the n-decane in the mixture. The relative response factor (F~) of each n-paraffin must not deviate from unity (1) by more than + 10 %. 9.3.3 Column Elution Characteristics--The column material, stationary phase, or other parameters can affect the elution order of non-paraffinic sample components, resulting

10. Calibration and Standardization 10.1 Analysis Sequence Protocol--Define and use a prede-

termined schedule of analysis events designed to achieve maximum reproducibility for these determinations. The schedule will include coofing the column oven to the initial starting temperature, equih'bration time, sample injection and system start, analysis, and final upper temperature hold time. 448

(@) D 2887 10. I. 1 After chromatographic conditions have been set to meet performance requirements, program the column temperature upward to the maximum temperature to be used and hold that temperature for the selected time. Following the analysis sequence protocol, cool the column to the initial starting temperature. 10.1.2 During the cool down and equilibration time, ready the integrator/computer system. If a retention time or detector response calibration is being performed, use the peak detection mode. For samples and baseline compensation determinations, use the area slice mode of integration. The recommended slice rate for this test method is 1.0 Hz (one slice per second). Other slice rates may be used if within the limits of 0.02 and 0.2 % of the retention time of the final calibration component (C44). Larger slice rates may be used, as may be required for other reasons, if provision is made to accumulate (bunch) the slice data to within these limits prior to determination of the boiling range distribution. 10.1.3 At the exact time set by the schedule, inject either the calibration mixture or sample into the chromatograph; or make no injection (baseline blank). At the time of injection, start the chromatograph time cycle and the integrator/computer data acquisition. Follow the analysis sequence protocol for all subsequent repetitive analyses or calibrations. Since complete resolution of sample peaks is not expected, do not change the detector sensitivity setting during the analysis. 10.2 Baseline Compensation Analysis--A baseline compensation analysis, or baseline blank, is performed exactly like an analysis except no injection is made. A blank analysis must be performed at least once per day. The blank analysis is necessary due to the usual occurrence of chromatographic baseline instability and is subtracted from sample analyses to remove any nonsample slice area from the chromatographic data. The blank analysis is typically performed prior to sample analyses, but may be useful if determined between samples or at the end of a sample sequence to provide additional data regarding instrument operation or residual sample carry-over from previous sample analyses. Attention must be given to all factors that influence baseline stability, such as column bleed, septum bleed, detector temperature control, constancy of carrier gas flow, leaks, instrument drift, etc. Periodic baseline blank analyses should be made, following the analysis sequence protocol, to give an indication of baseline stability. NOTE 9--If automaticbaselinecorrection(see Note 3) is providedby the gas chromatograph, further correction of area slices may not be required. However, if an electronic offset is added to the signal after baseline compensation, additional area slicecorrection may be required in the form of offset subtraction. Consult the specific instrumentation instructions to determine if an offset is applied to the signal. If the algorithm used is unclear, the slice area data can be examined to determine if further correction is necessary. Determine if any offset has been added to the compensated signal by examining the corrected area slices of those time slices which precede the ehition of any chromatographic unretained substance. If these corrected area slices(representing the true baseline) deviate from zero, subtract the average of these corrected area slicesfrom each corrected area slicein the analysis.

10.3 Retention Time Versus Boiling Point Calibration--A retention time versus boiling point calibration must be performed on the same day that analyses are performed. Inject an appropriate aliquot (0.2 to 2.0 IxL) of the calibra tion mixture (see 8.8) into the chromatograph, using the 449

analysis sequence protocol. Obtain a normal (peak detection) data record in order to determine the peak retention times and the peak areas for each component. Collect a time slice area record if a boiling range distribution report is desired. 10.3.1 Inspect the chromatogram of the calibration mixture for evidence of skewed (non-Gaussian shaped) peaks. Skewness is often an indication of overloading the sample capacity of the column, that will result in displacement of the peak apex relative to nonoverloaded peaks. Distortion in retention time measurement and hence errors in boiling point temperature determination will be likely if column overloading occurs. The column liquid phase loading has a direct bearing on acceptable sample size. Reanalyze the calibration mixture using a smaller sample size or a more dilute solution to avoid peak distortion. 10.3.2 Prepare a calibration table based upon the results of the analysis of the calibration mixture by recording the time of each peak maximum and the boiling point temperature in degrees Celsius (or Fahrenheit) for every component in the mixture, n-Paraffin boiling point temperatures are listed in Table 2. 10.3.3 Plot the retention time of each peak versus the corresponding normal boiling point temperature of that component in degrees Celsius (or Fahrenheit) as shown in Fig. 2. 10.3.4 Ideally, the retention time versus boiling point temperature calibration plot would be linear, but it is impractical to operate the chromatograph such that curvature is eliminated completely. The greatest potential for deviation from linearity will be associated with the lower boiling point paraffins. They will elute from the column relatively fast and have the largest difference in boiling point temperature. In general, the lower the sample initial boiling point, the lower will be the starting temperature of the analysis. Although extrapolation of the curve at the upper end is more accurate, calibration points must bracket the boiling range of the sample at both the low and high ends. 10.4 Reference Gas Oil AnalysismThe Reference Gas Oil No. 1 sample is used to verify both the chromatographic and calculation processes involved in this test method. Perform an analysis of the Gas Oil following the analysis sequence protocol. Collect the area slice data and provide a boiling point distribution report as in Sections 12 and 13. 10.4.1 The results of this reference analysis must agree with the values given in Table 3 within the range specified by the test method reproducibility (14.1.2). 10.4.2 Perform this reference gas oil confLrmation test at least once per day or as often as required to establish confidence in consistent compliance with 10.4.1. 11. Procedure

11. I Sample Preparation: 11.1.1 The amount of sample injected must not overload the column stationary phase nor exceed the detector linear range. A narrow boiling range sample will require a smaller amount injected than a wider boiling range sample. 11. I. 1.1 To determine the detector linear range refer to Practice E 594 for flame ionization detectors or Practice E 516 for thermal conductivity detectors. 11.1.1.2 The column stationary phase capacity can be estimated from the chromatogram of the calibration mixture (see 9.3.2). Different volumes of the calibration standard can

(~

D 2887

1100

600

1000 500 900 800 400 700 u" o

600

300

~, e.

~-

500 200

400

300 100 200 100

0

-100 0

I 5

I 10

I 15

I 20

I 25

I 30

I 35

-100 40

Retention Time, Minutes FIG. 2

Typical Calibration Curve

11.2 Sample Analysis--Using the analysis sequence protocol, inject a sample aliquot into the gas chromatograph. Collect a contiguous time slice area record of the entire analysis.

be injected to find the maximum amount of a component that the stationary phase can tolerate without overloading (see 10.3.1). Note the peak height for this amount of sample. The maximum sample signal intensity should not exceed this peak height. 11.1.2 Samples that are of low enough viscosity to be sampled with a syringe at ambient temperature may be injected neat. This type of sample may also be diluted with carbon disulfide to control the amount of sample injected to comply with 11.1.1. 11.1.3 Samples that are too viscous or waxy to sample with a syringe may be diluted with carbon disulfide. 11.1.4 Typical sample injection volumes are listed below.

12. Calculation 12.1 Correct the sample area slices for nonsample detector response by subtracting each blank analysis area slice (as determined in 10.2) from each sample area slice at the equivalent slice time. Also see Note 9 regarding automatic baseline correction. Sum the corrected area dices to obtain the cumulative corrected areas for each time interval during the run. 12.2 At the point on the chromatogram where the baseline at the end of the run first becomes steady as the total area point, record the total cumulative corrected area counts. Move back along the chromatogram until a cumulative area equals 99.5 % of the total area. Mark this point as the final boiling point (FBP).

Packed Columns: Stationary Phase Loading, %

Neat Sample Volume, ~tL

10 5

1.0 0.5

Open Tubular Columns: Film Thickness, ~

Neat Sample Volume, ~tL

0.8 to 1.5 1.8 to 3.0 3.0 to 5,0

0.1 to 0.2 0.1 to 0.5 0.2 to 1.0

NOT~ 10--Location of the final boiling point may be the most difficult step in this test method. Some samples have extremelylong tailing end portions due to graduallydecreasing quantifies of heavy materials. This fact, coupledwiththe natural tendencyof the chromato450

@

v

2eez

TABLE 4 RepeatabUity Noze--x ffi the average of the two results in "C and y : the average of the two results in "F.

TABLE 5 =

Reputably ~Off IBP §Yo 10-20 Y, 30 % 40 ~ 50-90 Y, 95 % FBP

Reproducibility

NOTE--X the averageof the two resultsin "C and y = the averageof the two resultsin "F. Reprodudt~lRy

YoOff

•C

°F

0.011 x 0.0032 (x + 100) 0.8 0.8 0.8 1.0 1.2 3.2

0.011 (y - 32) 0.0032 (y + 148) 1.4 1.4 1.4 1.8 2.2 5.8

oC

IBP 5Yo 10-20 % 30 % 40 ~ 50-90 ~; 95 • FBP

graphicbaselineto riseat the end of the run due to septum or column bleed or elutionof tracesof heavy compounds from previoussamples, can precludethe possibilityof the chromatogram returningpreciselyto the original baseline estabfished prior to the initial boiling point of the sample. Thus, the most satisfactory procedure is to inspect the chromatngram and the area counts at each interval near the end of the run to determine the point at which the rate of change of the chromatographic s~-~l has reached a constant low value of no greater than 0.01% of the total area counts. In some rather unusual cases, a sample may have individual peaks, separated at the end of the run, which return to baseline between the peaks. In such cases, the total area point of the sample obviously is somewhere beyond the last detectable peak. 12.3 Observe the area counts at the start of the run until the point is reached where the cumulative area count is equal to 0.5 % o f the total area (see 12.2). Mark this point as the initial boiling point (IBP) o f the sample. 12.4 Divide the cumulative area at each interval between the initial and final boiling points by the total area (see 12.2) and multiply by 100. This will give the cumulative percent of the sample recovered at each time interval. 12.5 Tabulate the cumulative percent recovered at each interval and the retention time at the end of the interval. Using linear interpolation where necessary, determine the retention time associated with each percent between 1 and 99. 12.6 For each percent and its associated retention time, determine the corresponding boiling temperature from the ealibmtion table (see 10.3.2). 13. Report 13.1 Report the temperature to the nearest 0.5°C (I°F) at 1% intervals between 1 and 99 % and at the IBP (0.5 %) and the FBP (99.5 %). NOTE 1l - - I f a plot of the boiling point distribution curve is desired, use graph paper with uniform subdivisions and use either retention time or temperature as the horizontal axis. The vertical axis will represent the boiling range distribution (0 to 100 %). Plot each boiling temperature against its corresponding normalized percen.t. Draw a smooth curve connecting the points. 14. Precision and Bias 6

14.1 Precision--The precision of this test method as determined by the statistical examination of the interlaboratory test results is as follows: 14. I. 1 Repeatability---The difference between successive 6Supporting data are availablefrom ASTMHeadquarters. Request RR:D021406. 451

0.066 x 0.015 (x + 100) 0.015 (x + 100) 0.013 (x + 100) 4.3 4.3 5.0 11.8

TABLE 6 Y, Off IBP 5% 10 % 20 • 30 % 40 Y~ 50 % 60 % 70 % 80 % 90 % 95 ~ FBP

°F 0.06 (y 0.015 (y + 0.015 (y + 0.013 (y + 7.7 7.7 9.0 21.2

32) 148) 148) 148)

Round Robin Range of Results

Range of Results, 112-213 133-286 139-312 151-341 161-358 171-370 182-381 196-390 206-401 219-412 233-426 241-437 274-475

°C

Range of Results, °F 234-415 271-547 282-594 304-646 322-676 340-698 360-718 385-734 403-754 426-774 451-799 466-819 525-887

test results obtained by the same operator with the same apparatus under constant operating conditions on identical test material would, in the long run, in the normal and correct operation of the test method, exceed the following values by only 1 case in 20. See Table 4. 14.1.2 Reproducibility--The difference between two single and independent results obtained by different operatops working in different laboratories on identical test material would, in the long run, exceed the following values only 1 case in 20. See Table 5. NOTE 121This precision estimate is based on the analysis of 9 samples by 19 laboratories using both packed and open tubular columns. The range of results found in the round robin are listed in Table 6. 14.2 BiasmThe procedure in Test Method D 2887 for determining the boiling range distribution of petroleum fractions by gas chromatography has no bias because the boiling range distribution can only be defined in terms of a test method. 14.2.1 A rigorous, theoretical definition of the boiling range distribution of petroleum fractions is not possible due to the complexity of the mixture as well as the unquantifiable interactions among the components (for example, azcotropic behavior). A n y other means used to define the distribution would require the use of a physical process such as a conventional distillationor gas chromatographic characterization. This would therefore result in a method-dependent definition and would not constitute a true value from which bias can be calculated.

15. Keywords 15.1 boiling range distribution; distillation;gas chromatography; petroleum; petroleum fractions; simulated distillation

o 288z APPENDIXES (Nonmandatory Information) X1. BOILING POINTS OF NONPARAFFINIC HYDROCARBONS

boiling points are plotted against the observed retention times. If columns containing different percentages of stationary phase or different temperature programming rates were used, the slope and curvature of the n-paraffin curve (solid line) would change, but the relative relationships would remain essentially the same. Deviations of simulated distillation boiling points, as estimated from the curve, from actual boiling points for a few compounds are shown in Table X I.2. The deviations obtained by plotting boiling

X I.I There is an apparent discrepancy in the boiling point of multiple ring-type compounds. When the retention times of these compounds are compared to n-paraffins of equivalent atmospheric boiling point, these ring compounds appear to be elnted early from methyl silicone rubber columns. A plot showing 36 compounds other than n-paraffins plotted along the calibration curve for n-paraffins alone is shown in Fig. X I.I. The numbered dots are identified in Table X l.l. In this figure the atmospheric TABLE X1.1 NO. 2 3 5 6 8 9 10 12

13 14 15 17 18 19 20 21 23 25 26

Boiling(OF) Point, °C

Compound IdentificationuNumbered Dots (See Rg. X1.1) Compound

80 (176) 84 (183) 111 (231) 116 (240) 136 ( 2 7 7 ) 139 (282) 143 ( 2 8 9 ) 152 (306) 159 (319) 171 (339) 173 ( 3 4 4 ) 178 ( 3 5 2 ) 183 (361) 186 (366) 194 (382) 195 ( 3 8 3 ) 213 (416) 218 (424) 221 ( 4 3 0 )

benzene thiophane toluene pyrldlne 2,5-dimethylthlophane p-xylane di.n.propylsulflde cumane 1-hexahydrolndan 1.decane sec-butylbanzane 2,3-dlhydrolndane n-butylbanzane trans-decalln c/s-decalln di-n-propyldlsulfide 1-dodecane naphthalene 2,3-benzothlophene

482.2

|

Boiling(OF) Point. °C

Number

I

i

i

i

Compound

27 28 30 31

227 (441) 234 ( 4 5 3 ) 241 ( 4 6 6 ) 295 ( 4 7 3 )

dl-n-amylsulflde tr~zane 2-methylnaphthalane 1-methylnaphthalane

34 35

264 (489) 279 (534)

Indole acana~

38 39

298 (568) 314 (568)

n-decylbenzene l-octadecene

41 42

339 (642) 342 (647)

phenanthrane anthracene

44 45 47 49 50

346 (655) 395 (743) 404 (796) 438 (820) 447 (337)

acridine pyrene trlphenylane naphthacane chrysane

i

I

I

|

50o

426.6 371.1 O o

4 2 \ 44

41 ~:~ 3,oJ

315.5

r.

,m

O a.

260

31-.~o34,~.^

O~ e. ,D E

"~ fll 204.4 148.9 6o~5-8 10

93.3 37.8

I

0

I

10

I

I

20

I

I

I

30

I

I

40

I

50

I

I

60

I

I

70

I

80

Time, Minutes FIG. X1.1

Boiling Point--Retention Time Relationships for Several High-Boiling Multiple-Ring Type Compounds (See Table X1.1)

452

~1~ D 2887 TABLE X1.2 Compound

Deviations of Simulated Distillation Boiling Points From Actual Boiling Points Boiling Point, °C (°F) (760 ram)

(760 mm)

80 (176) 84 063) 111 (231) 139 (282) 213 (416) 218 (424) 221 (430) 241 (466) 245 (473) 332 (630) 339 (642) 342 (647) 395 (743) 447 (637)

+3 (+6) +4 (+7) +2 (+3) 0 (0) 0 (0) -11 (-20) -13 (-23) -12 (-21) -12 (-21) -32 (-58) -35 (-63) -36 (-64) -48 (-87) -60 (-108)

Benzene Thiophene Toluene p-Xylene 1-Dodecene Napht~ime 2,3-Benzothlophene 2-Methylnaphthalene 1-Methylnaphthalene DIbenzothlophene Phenanthrene Anthracene Pymne Chrysene

Deviations from Actual Boiling Point, °C (oF) (10 ram) - 2 (-4) +1 (+2) -1 (-2) +2 (+4) 0 (0) - 4 (-8) 0 (0) - 2 (-3) -1 (-1) - 6 (-10) - 9 (-16) - 8 (-15) -16 (-29) A

A No data at 10 mm fo~ ctvyasne. TABLE X l . 3 Weight Percent OffA IBPo 10 20 30 40 50 60 70 80 90 95 100

Distillation of Heavy Gas Oils

Virgin Gas Oil TBP,A °C (°F) 230 (446) 269 (517) 304 (580) 328 (622) 343 (650) 567 (693) 394 (742) 417 (783) 447 (836) ... ... ...

SD, a °C (°F) 215 (419) 265 (506) 294 (562) 321 (610) 348 (659) 373 (704) 409 (749) 424 (795) 451 (844) 488 (910) 511 (951) 543 0009)

High-Sulfur Coker Gas Oil TBP, °C (°F) 223 (433) 274 (526) 296 (565) 316 (600) 336 (636) 356 (672) 377 (710) 398 (751) 421 (800) 462 (863) 482 (900) ...

SO, °C (°F) 209 (409) 259 (498) 284 (544) 312 (593) 344 (651) 364 (688} 386 (727) 410 (770) 434 (814) 467 (872) 494 (922) 542 (1007)

"Decanted" Oil TBP. °C (°F) 190 (374) 318 (605) 341 (645) 357 (675) 377 (710) 390 (734) 410 (770) 425 (797) 445 (833) ... ... ...

SD, °C (°F) 176 (348) 302 (575) 338 (640) 358 (676) 375 (707) 391 (735) 409 (756) 425 (797) 443 (830) 469 (876) 492 (918) 542 (1007)

A TBP - True boiling point. e SD - Simulated distillation boiling point. o IBP - Initial boiling point.

(5000F) to prevent cracking of the sample. Thus, distillation data are subject to the same deviations experienced in simulated distillation by gas chromatography. A comparison of data obtained from true boiling point (TBP) distillation with those obtained from simulated distillationof three high boiling petroleum fractions is shown in Table XI.3. The T B P distillationswere made on I00 theoreticalplate spinning band columns at 1 m m H g pressure. X 1.3 The decanted oil is of particular interestbecause it contains a high presence of polycyclic aromatic compounds and the high sulfur coker gas oil should contain ring-type sulfur compounds and complex olefinictypes.

points at 10 mm rather than 760 mm are tabulated also. It is apparent that the deviation is much less at 10 mm pressure. This indicates that the distillation data produced by gas chromatography closely approximates those obtained in reduced pressure distillation. Since the vapor-pressure-temperature curves for multiple-ring type compounds do not have the same slope or curvature as those of n-paraffins, an apparent discrepancy would exist when n-paraffin boiling points at atmospheric pressure are used. X1.2 However, this discrepancy does not introduce any significant error when comparing with laboratory distillation, because the pressure must be reduced in such procedures when overhead temperatures reach approximately 260°C

X2. AGREEMENT WITH CONVENTIONAL DISTILLATION X2.1 This test method (D 2892) is the standard for conventional distillationof petroleum products. X2.2 This test method has been compared to Test Method D 2892 on the same samples by a number of laboratories.7-9 In all cases, agreement between the two

methods has been very good for petroleum products and fractionswithin the scope of this testmethod. X2.3 The time required for analysisby thistestmethod is approximately one-tenth of that required for Test Method D 2892, and Test Method D 2892 has difficultyestablishing the IBP and FBP accurately.

? Green, L E., Schumauch, L. J., and Worman, J. C., Anal. Chem., Vol 32, 1960, p. 904. s I-liclmrson, J. F., A,.VI'MSIP

577M, 1973, p. 71.

9 Green, L. E., Chromatograph Gives Boiling Point, Hydrocarbon Processing, May, 1976.

453

o 2ee7 The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reepproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend, if you feel that your comments have not received • fair hearing you should make your views known to the ASTM Committee on Standards, 100 BaIT Harbor Drive, West Conohohuckan, PA 19428.

454

(~

Designation:D 2892 - 95 Standard Test Method for Distillation of Crude Petroleum (15-Theoretical Plate Column) 1 This standard is issued under the fixed designation D 2892; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (4) indicates an editorial change since the last revision or reapproval.

1.5 The values stated in SI units are standard. The values given in parentheses are provided for information purposes only. 1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific precautionary notes, see Section 9,

1. Scope 1.1 This test method describes the procedure for the distillation of stabilized crude petroleum2 to a final cut temperature of 400"C AET (Atmospheric Equivalent Temperature). The test method employs a fractionating column having an efficiency of 14 to 18 theoretical plates operated at a reflux ratio of 5:1. Performance criteria for the necessary equipment is specified. Some typical examples of acceptable apparatus are presented in schematic form. This test method offers a compromise between efficiency and time in order to facilitate the comparison of distillation data between laboratories. 1.2 The test method details procedures for the production of a liquified gas, distillate fractions and residuum of star/dardized quality on which analytical data can be obtained, and the determination of yields of the above fractions by both mass and volume. From the above information a graph of temperature versus mass-percent distilled can be produced. This distillation curve corresponds to a laboratory technique which is defined at 15/5 (15 theoretical plate column, 5:1 reflux ratio) or TBP (true boiling point). 1.3 This test method can also be applied to any petroleum mixture except liquified petroleum gases, very light naphthas, and fractions having initial boiling points above 400"C. 1.4 This test method contains the following Annexes: 1.4.1 Annex A1--Test Method for the Determination of the Efficiency of a Distillation Column, 1.4.2 Annex A2nTest Method for the Determination of the Dynamic Holdup of a Distillation Column, 1.4.3 Annex A3--Test Method for the Determination of the Heat Loss in a Distillation Column (Static Conditions), 1.4.4 Annex A4~Test Method for the Verification of Temperature Sensor Location, 1.4.5 Annex A5~Test Method for Determination of the Temperature Response Time, 1.4.6 Annex A6~Practice for the Calibration of Sensors, 1.4.7 Annex A7~Test Method for the Verification of Reflux Dividing Valves, 1.4.8 Annex A8--Test Method for Dehydration of a Sample of Wet Crude Oil, 1.4.9 Annex A9mPractice for Conversion of Observed Vapor Temperature to Atmospheric Equivalent Temperature (AET), and 1.4.10 Annex A 10nPractice for Performance Check.

2. Referenced Documents 2.1 A S T M Standards: D 941 Test Method for Density and Relative Density (Specific Gravity) of Liquids by Lipkin Bicapillary Pycnometer3 D 1217 Test Method for Density and Relative Density (Specific Gravity) of Liquids by Bingham Pycnometer3 D 1298 Test Method for Density and Relative Density (Specific Gravity) or API Gravity of Crude Petroleum and Liquid Petroleum Products by Hydrometer Method 3 D 2427 Test Method for Determination of C2 through C 5 Hydrocarbons in Gasolines by Gas Chromatography3 D 4052 Test Method for Density and Relative Density of Liquids by Digital Density Meter4 D4057 Practice for Manual Sampling of Petroleum and Petroleum Products4 D 4177 Practice for Automatic Sampling of Petroleum and Petroleum Products4 3. Terminology 3.1 Definitions: 3.1.1 adiabaticitynthe condition in which there is no significant gain or loss of heat throughout the length of the column. 3.1.2 Discussion--When distilling a mixture of compounds as is the case of crude petroleum, there will be a normal increase in reflux ratio down the column. In the case where heat losses occur in the column, the internal reflux is abnormally greater than the reflux in the head. The opposite is true when the column gains heat, as with an overheated mantle. 3.2 boilup rateJthe quantity of vapor entering the column per unit of time. 3.2.1 Discussion--It is expressed in millilitres of liquid per hour for a given column or in miUilitres per hour per square centimetre of cross-sectional area for comparative

i This test method is under the jurisdiction of ASTM Committee I)-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee I)02.08 on Volatility. Current edition approved Dec. 10, 1995. Published April 1996. Originally published as D 2892 - 70 T. Last previous edition D 2892 - 90. 2 Defined as having a Reid vapor pressure less than 82.7 kPa (12 psi).

3 Annual Book of ASTM Standards, Vol 05.01. 4 Annual Book of ASTM Standards, Vol 05.02.

455

~1~"~ D 2892 purposes. In the latter case, it refers to the test mixture of n-heptane and methylcyclohexane in the efficiency evaluation (Annex A1) and is measured at the bottom of the column. The maximum boilup of the n-heptane-methylcyclohexane test mixture is that which the column can handle under stable conditions without flooding. In routine adiabatic operation, the boilup rate can be estimated roughly from the takeoff rate multiplied by the reflux ratio plus one. 3.3 debutanization of crude petroleum--the removal of the light hydrocarbons up to and including n-butane, and retention of the heavier hydrocarbons. 3.3.1 Discussion--In practice, a crude petroleum is regarded as debutanized if the light hydrocarbon cut collected in the cold trap contains more than 95 % of the C2 to C4 hydrocarbons and less than 5 % of the C5 hydrocarbons initially present in the sample. 3.4 distillation pressure--the pressure measured as close as possible to the point where the vapor temperature is taken, normally at the top of the condenser. 3.5 distillation temperature--the temperature of the saturated vapor measured in the head just above the fractionating column. 3.5.1 Discussion--It is also known as the head temperature or the vapor temperature. 3.6 dynamic hold-up--the quantity of liquid held up in the column under normal operating conditions. 3.6.1 Discussion--It is expressed as a percentage of the packed volume for packed columns so that the data can be compared. For real plate columns, it is expressed in millilitres per plate. The data can only be compared with others of the same diameter because of different tray spacing. TABLE 1

Data for packed columns cannot be compared with those of real plate columns except in absolute units of milliliters per theoretical plate (see Table 1). Dynamic hold-up increases with increasing distillation rate up to the flood point, and varies from one kind of fractionator to another. 3.7 flood pointmthe point at which the velocity of the upflowing vapors obstructs the downcoming reflux and the column suddenly loads with liquid. 3.7.1 DiscussionmUnder these conditions no vapor can reach the head and the heat to the distillation flask must be reduced to establish normal operations again. The flood point is normally determined during the efficiency evaluation of a column using the n-heptane-methylcyclohexanetest mixture (Annex A l). 3.8 internal reflux--the liquid normally running down inside the column. 3.8.1 Discussion--In the case of an adiabatic column when distilling a pure compound, the internal reflux is constant from top to bottom and is equal to the reflux at the reflux divider. When distilling crude petroleum, the fractionation occurring in the dynamic holdup will cause a temperature gradient to be established with attendant greater amount of internal reflux at the bottom of the column. 3.9 pressure drop--the difference between the pressure measured in the condenser and the pressure measured in the distillation flask. 3.9.1 Discussion--It is expressed in kilopascals (mm Hg) per meter of packed height for packed columns, or kilopascals (mm Hg) overall for real plate columns. It is higher for aromatics than for paraffins, and for higher molecular weights than for lighter molecules, at a given boilup rate.

Data for n-Heptane-Methylcyclohexane Test Mixture at 75 % of Maximum Bollup and 101.3 kPa (760 mm Hg)

Propak A'B'c'D'H Column Diameter Packing size Boilup, ml_/h x cm Dynamic Holdup, Yo mL/theorettcal plate Pressure drop, kPa/m mm Hg/m kPa/theoretical plate mm Hg/theorettcel plate HETP, kPa/theorettcel, plate mm Hg/theoretical, plate For 15-plata Towers: Packed height, cm (plates) Packed volume, mL Dynamic holdup, mL Pressure Drop, kPa mm Hg Charge Volume, L Minimum (2 ~=Holdup) Maximum (4 ~ Holdup)

25 4 650 17 3.2 1.2 9.0 0,045 0.34 5.05 38

Hellpake'F'e

50

70

25

50

6

6

#2917

#2918

6770 15.3 16 1.05 7.9 0.056 0.42 7.05 53

675 17.0 393 0.94 7.1 0.06 0.43 8.1 61

300 15 1,6 0.53 4 0.01 0,08 2.8 21

350 14.3 8.7 1.41 10.6 0,045 0.34 4.3 32

57 280 47 0.68 5.1

80 1570 240 0.84 6.3

91 34600 5900 0.86 6.5

31.5 155 23 0.17 1.3

48 917 131 0.68 5.1

2.4 1.2

12.0 6.0

30 15

1.0 0.525

6.5 3.3

Perforated PlatesH.J.x 50

25

50

640

660 8.0 12.3

NA 0.15 1.1 (60 ~) (60 Y=)

NA 0.16 1.2 (66 ~) (65 '~)

810 8.0 2.0 0.92 6.9 0.05 0.35 6.4 48

1050 10.0 26 0.75 5.6 0.05 0.37 8.8 66

(25)

(23)

2.2 16.5

184 3.7 27.6

72 353 28 0.70 5.3

99 1940 194 0.73 5.5

9.2 4.6

1.4 0.7

9.7 4.9

NA---not applicable. A Cooke, G. M. and Jameson, B. G. Analytical Chemistry, Vol 27, 1955, p. 1798. a Struck, R. T. and Kinner, C. R. Industrial and Engineering Chemistry, Vol 42, 1950, p. 77. c Cannon, M. R. Industrial and Engineering Chemistry, Vol 41, No. 9, 1949, p. 1953. o Bulletin 23, Scientific Development Co. P.O. Box 795, State College, PA 16801. Bulletin of Podblelniak Div. of Reliance Glass Works, P.O. Box 825, Bensenville, IL 60106. F Feldman, J., et el Industrial and Engineering Chemistry, Vol 45, January 1953, p. 214. e Helipak Performance Characteristics, Begemean, C, R. and Turkal, P. J. (Laboratory Report of Podbielniak Inc.) 1950. H Cooke, G. M. Analytical Chemistry, Vol 39, 1967, p. 286. i Bregg, L. B. Industrial and Engineering Chemistry, Vol 49, 1947, p. 1062. J Umholtz, C. L. and Van Winkle, M. Petroleum Refiner, Vol 34, 1955, p. 114 for NH:MCH. Pressure Drop Calculated from data obtained on o- and m-xylene binary. K Olderehaw, C. F. Industrial and Engineering Chemistry, VOl 13, 1941, p. 265.

456

Wire MeshH.I

25

~'z]~ D 2892 3.10 reflux ratio, R m t h e ratio of reflux to distillate. 3.10.1 Discussion~The vapor reaching the top of the column is totally condensed and the resulting liquid is divided into two parts. One part L (reflux), is returned to the column and the other part, D (distillate), is withdrawn as product. The reflux ratio (R = L/D), can vary from zero at total takeoff (L = 0) to infinity at total reflux (D --- 0). 3.11 static hold-up or wettagewthe quantity of liquid retained in the column after draining at the end of a distillation. 3.11.1 Discussion--It is characteristic of the packing or the design of the plates, and depends on the composition of the material in the column at the final cut point and on the final temperature. 3.12 takeoff ratemthe rate of product takeoff from the reflux divider expressed in millilitres per hour. 3.13 theoretical plate--the section of a column required to achieve thermodynamic equilibrium between a liquid and its vapor. 3.13.1 Discussion~The height equivalent to one theoretical plate (HETP) for packed columns is expressed in millimeters. In the case of real plate columns, the efficiency is expressed as the percentage of one theoretical plate that is achieved on one real plate.

4. Summary of Test Method 4.1 A weighed sample of 1 to 30 L of stabilized crude petroleum is distilled to a maximum temperature of 400"C AET (Atmospheric Equivalent Temperature) in a fractionating column having an efficiency at total reflux of at least 14 but not greater than 18 theoretical plates. 4.2 A reflux ratio of 5:1 is maintained at all operating pressures, except that at the lowest operating pressures between 0.674 and 0.27 kPa (5 and 2 mmHg) a reflux ratio of 2:1 is optional. In cooperative testing or in cases of dispute, the stages of low pressure, the reflux ratios, and the temperatures of cut points must be mutually agreed upon by the interested parties prior to beginning the distillation. 4.3 Observations of temperature, pressure and other variables are recorded at intervals and at the end of each cut or fraction. 4.4 The mass and density of each cut or fraction are obtained. Distillation yields by mass are calculated from the mass of all fractions including liquified gas cut and the residue. Distillation yields by volume of all fractions and the residue at 15"C, are calculated from mass and density. 4.5 From these data the TBP curves in mass or volume percent, or both, versus atmospheric equivalent temperature are drawn. 5. Significance and Use 5.1 This test method is one of a number of tests conducted on a crude oil to determine its value. It provides an estimate of the yields of fractions of various boiling ranges and is therefore valuable in technical discussions of a commercial nature. 5.2 This test method corresponds to the standard laboratory distillation effÉciency referred to as 15/5. The fractions produced can be analyzed as produced or combined to produce samples for analytical studies, engineering and product quality evaluations. The preparation and evaluation

of such blends is not part of this test method. 5.3 This test method can be used as an analytical tool for examination of other petroleum mixtures with the exception of LPG, very light naphthas, and mixtures with initial boiling points above 400"C.

6. Apparatus 6.1 Distillation at Atmospheric PressuremAll components must conform to the requirements specified below. Automatic devices can be employed provided they meet the same requirements. A typical apparatus is illustrated in Fig. 1. 6.1.1 Distillation Flask--The distillation flask shall be of a size that is at least 50 % larger than the volume of the charge. The size of the charge, between 1.0 and 30 L, is determined by the holdup characteristics of the fractionating column as shown in Table 1 and described in Annex A2. The distillation flask shall have at least one sidearm. 6.1.1.1 The sidearm is used as a thermowell. It shall terminate about 5 mm from the bottom of the flask to ensure its immersion at the end of the distillation. When a second sidearm is present, it can be used for pressure drop detection with a nitrogen bleed or for mechanical stirring or both. 6.1.1.2 If a magnetic stirrer is used with a spherical flask, the flask shall have a slightly flattened or concave area at the bottom on which the magnetic stirrer can rotate without grinding the glass. In this case, termination of the thermowell shall be off center 40 _.+ 5 mm to avoid the magnetic stirring bar. Boiling chips can be used as an alternative to a stirrer. 6.1.1.3 WarningmWhile the advantage of visibility in glass distillation flasks is desirable, flasks of glass may become hazardous the larger the charge they contain. For this reason, glass flasks of a volume greater than I0 L are not recommended. 6.1.2 Heating SystemwHeating of the flask shall be provided in such a way that full boilup can be maintained at a steady rate at all pressure levels. An electric heating mantle covering the lower half of the flask and having one third of the heat in an element located in the bottom central area and the remaining two thirds in the rest of the hemisphere is recommended. While proportioning controllers are preferred, heat input can be manually adjusted by use of a variable auto transformer on each circuit, the smaller heater being automatically controlled by an instrument sensing the pressure drop of the column as registered in a differential pressure instrument or alternatively by direct measurement of distillation rate. 6.1.2.1 Minimum wattage required to provide full boilup of crude petroleum is approximately 0.125 W / m L of charge. Twice this amount is recommended for quick heat-up. 6.1.2.2 The heat density in the flask heaters is approximately equal to 0.5 to 0.6 W/cm 2. This requires the use of nickel reinforced quartz fabric to ensure a reasonable service life. 6.1.2.3 Immersion heaters can be employed in a similar way and have the advantage of faster response, but they are more fragile and require a specially designed flask to ensure that the heating elements remain immersed at the end of the run. When used, their heat density should be approximately equal to 4 W/cm 2. 6.1.2.4 The upper half of the flask shall be covered with a mantle to avoid unnecessary heat losses from the upper 457

~

D 2892 ,J

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i

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DRY ICE T R A P S I

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~RATURE

I

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SENSOR

PRODUCT COOLER

N2

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I

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u

N2 BUBBLER

STILLING

FLASK

WITH

MANTLES

/ I

STIRRING

FIG. 1

MOTOR

Apparatus

surface and shall have an electric heater supplying about 0.25 W/cm 2 at full-rated voltage. 6.1.3 Fractionating Column--The fractionating column must contain either particulate packing or real plates similar to those whose performance characteristics are summarized in Table 1 and meet the specifications stated in 6.1.3.1 through 6.1.3.4. Table 2 lists current North American suppliers of suitable packings. 6.1.3.1 The internal diameter shall be between 25 and 70 mm. 6.1.3.2 The efficiency shall be between 14 and 18 theoret-

ical plates at total reflux when measured by the procedure described in Annex A I. 6.1.3.3 The fractionating column shall be comprised of a integral glass column and reflux divider totally enclosed in a highly reflective vacuum jacket having a permanent vacuum of less than 0.1 mPa (~10 -6 mm Hg). It shall be essentially adiabatic when tested in accordance with Annex A3. 6.1.3.4 The column shall be enclosed in a heat insulating system, such as a glass-fabric mantle, capable of maintaining the temperature of the outer wall of the glass vacuum jacket equal to that of the internal vapor temperature. In order to 458

~ TABLE 2

North American Sources of Commercially Available Packing Materials

Name

Size

Propak

6 by 6 mm

Helipak

2.5 by 4 mm

Perforated plates

25 and 50 mm

Knitted wire meshGoodloe multiknit

D 2892 calibrated and graduated to permit reading to the nearest 1%.

6.1.9 Sensing and Recording Apparatus:

Source Scientific Development Co. P.O. Box 795 State College, PA 16801 Reliance Glass Works Inc. P.O. Box 825 Bensenville, IL 60106 Reliance Glass Works Inc. P.O. Box 825 Bensenville, IL 60106 W.A. Sales Inc. 419 Harvester Ct. Wheeling, IL 60090 Pegasus Industrial Specialties Ltd. P.O. Box 319 Agincourt, Ontario MIS 3B9 Canada Packed Column Co. 970 New Durham Rd. Edison, NJ 08817

verify this, the vacuum jacket shall have a temperature sensor such as a thermocouple soldered to about 6 cm 2 of thin copper or brass sheet and fastened to the outer wall of the glass jacket at a level just below the reflux divider. 6.1.3.5 The adjustable reflux divider shall be located about one column diameter above the top of the packing or topmost plate. It must be capable of dividing the condensate with an accuracy of better than 90 % between the column and the takeoff line over a range of rates between 25 % and 95 % of the maximum boilup rate of the column when determined in accordance with Annex A7. 6.1.4 Condenser--The condenser shall have sufficient capacity to condense essentially all the C4 and C5 vapors from the crude at the specified rate using a coolant temperature o f - 2 0 " C . 6.1.5 Cold Traps--Two efficient traps of adequate capacity cooled by dry ice and alcohol mixture shall be connected in series to the vent line of the condenser when light hydrocarbons are present, as at the beginning of the distillation. For vacuum distillation, a Dewar style trap also cooled by dry ice is used to protect the vacuum gage from vapors. 6.1.6 Gas Collector--If uncondensed gas is to be measured, a gas meter can be connected to the outlet of the cold trap but with a calcium chloride drying tube between them to keep moisture from collecting in the traps. When analysis of the gas sample is required, the gas can be collected in an empty plastic balloon of suitable size either in place of the meter or following it. The volume of its contents can be determined by calculation from the rise in pressure after expanding the sample into an evacuated vessel of known volume. 6.1.7 Fraction Collector--This part of the apparatus permits the collection of the distillate without interruption during withdrawal of product from the receiver under atmospheric or reduced pressure. It also permits removal of product from the vacuum system, without disturbing conditions in the column. 6.1.8 Product Receivers--The receivers shall be of suitable size for the quantity of crude petroleum being distilled. The recommended capacity is from 100 to 500 mL. They shall be

6.1.9.1 The tip of the temperature sensor shall be located above the top of the packing or the topmost glass plate and in close proximity to the reflux divider but not in contact with the liquid reflux. The location must be proved by the method described in Annex A4. It shall have a cooling time of not more then 175 s as described in Annex A5. The sensor must be calibrated as described in Annex A6. The vapor temperature is measured to the nearest 0.5"C and recorded either manually or automatically. 6.1.9,2 The pressure drop during operation is measured by means of a manometer or pressure transducer connected between the flask and the condenser. A very small flow of nitrogen (8 cm3/s) inserted between the manometer and the flask will prevent condensation in the connecting tube. The boilup rate is normally controlled by sensing the pressure drop in the column. 6.2 Distillation Under Reduced Pressure--In addition to the apparatus listed in 6. l, the apparatus for distillation under reduced pressure shall include the following: 6.2.1 Vacuum PumpmThe vacuum system, shall be capable of maintaining smooth pressure operation at all pressure levels. It must have the capacity to draw down the pressure in the receiver(s) from atmospheric to 0.25 kPa (2 m m Hg) in less than 30 s so as to avoid disturbance of the system during emptying of receivers under vacuum. Alternatively, a separate p u m p can be employed for this purpose. 6.2.2 Vacuum Gage." 6.2.2.1 The gage for measuring subatmospheric pressures shall have an accuracy at least equal to that stated below: Distillation Pressure kpa mm Hg 100-13.3 13.3-1.33 1.33-0.266

760 to 100 99 to 10 9 to 2

Accuracy kPa

mm Hg

0.13 0.013 0.006

1.0 0.1 0.06

6.2.2.2 The McLeod gage can achieve this accuracy when properly used, but a mercury manometer will permit this accuracy only down to a pressure of about 1 kPa and then only when read with a good cathetometer (an instrument based on a telescope mounted on a vernier scale to determine levels very accurately). An electronic gage such as the Baratron is satisfactory when calibrated from a McLeod gage but must be rechecked periodically as described in Annex A6. A suitable pressure calibration setup is illustrated in Fig. A6.3. Vacuum gages based on hot wires, radiation, or conductivity detectors are not recommended. NOTE l--Suitable instruments for measuring the pressure of the system during the test are the tensimeter or an electronic pressure gage, provided the output is traceable to a primary gage, such as the non-tilting McLeod gage. 6.2.2.3 The point of connection o f t h e vacuum gage to the system shall be as close as practical to the reflux dividing head. The connecting tubing must be of sufficient diameter to ensure that no measurable pressure drop occurs in the line. In no case shall the vacuum gage connection be near the vacuum pump. 6.2.2.4 All gages must be carefully protected from condensible vapors, especially water vapor, by a cold trap maintained at the temperature of dry ice.

459

~') D 2892 9.1.3 Determine the density of the sample by Test Methods D 941, D 1217, or D 1298. 9.1.4 Calculate to within __.5 %, the mass of crude petroleum corresponding to the desired volume of the charge. Weigh to the nearest 1%, this quantity of sample into the flask. 9.1.5 Attach the flask to the column and connect the pressure drop measuring device. Install the heating system, stirrer, and support device.

6.2.3 Pressure Regulator--The regulator must maintain the pressure in the system essentially constant at all operating pressures. Automatic regulation can be achieved by a device that bleeds air into the pumping line near the pump on demand. A satisfactory device is a solenoid valve positioned between the vacuum source and a surge tank of at least 10-L capacity. Alternatively, a manual bleed valve can be maintained by a trained operator with a minimum of attention.

7. Sampling 7.1 Obtain a sample for distillation in accordance with instructions given in Practice D4057 or Test Method D 4177. The sample must be received in a sealed container and show no evidence of leakage. 7.2 Cool the sample to between 0 and 5"C by placing it in a refrigerator for several hours (preferably overnight) before opening. 7.3 If, upon opening there is evidence of water, perform a preliminary distillation to remove the water following the instructions in Annex A8. 7.4 If the sample appears waxy or too viscous, raise the temperature to 5"C above its pour point. 7.5 Agitate the sample by whatever means are appropriate to its size to ensure that it is well-mixed.

NOTE 2--Warning--Poisonous H2S gas is frequently evolved from crude oil and precautions must be taken either to absorb the gas that passes through the cold trap or to vent it to a safe place. 9.2 Debutanization: 9.2.1 For necessary apparatus refer to 6.1.5 and 6.1.6. 9.2.2 Begin circulation of refrigerant at a temperature no higher than -20"C in the condenser, distillate cooler, and receiver if so equipped. 9.2.3 Record the barometric pressure at the beginning and periodically throughout the distillation. 9.2.4 Apply heat to the flask at such a rate that vapors reach the top of the column between 20 and 50 min after startup. Adjust heat input so as to achieve a pressure drop.of less than 0.13 kPa/m (1.0 m m He/m) in packed columns or less than 0.065 kPa (0.5 m m Hg) in real plate columns. Program automated equipment according to the above directions. Turn on the stirring device if used. 9.2.5 Allow the column to operate at total reflux until the vapor temperature reaches equilibrium but not longer than 15 min after the first drop of condensate appears in the reflux divider. 9.2.6 Record the vapor temperature as the initial vapor temperature. 9.2.7 Stop the circulation of the refrigerant and observe the vapor temperature. When the vapor temperature reaches 15"C, start the circulation of refrigerant again. 9.2.8 If the vapor temperature drops below 15"C, continue refluxing for at least 15 rain. Repeat 9.2.7. If the vapor temperature remains at 15"C or rises, continue with the atmospheric distillation.

8. Preparation of Apparatus 8.1 Clean and dry the distillation column and all the ancillary glass apparatus before the distillation begins. 8.2 Ensure that the system is leak-free and all heaters, control devices, and instruments are on and in working order. A clock or other timing device should be ready for use. 9. Procedure

9.1 Charging." 9.1.1 The charge size shall be such that the dynamic hold-up as determined in accordance with Annex A2 is between 2 % and 4 % of the charge when operating at 75 % of maximum boilup (see Table 1). Chill the flask to a temperature not lower then 0*C. 9.1.2 Insert the stirring device or place some pieces of glass or porcelain into the flask to control bumping.

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OPERATING

I I I I:11 I

5.0 PRESSURE,

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FIG. 2 Approxim=tePressure Drop-Fraction=tomUsing Propak 460

' I,

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i

I1 I I ' II

"1: I.t-I ','50

I00

It~ D 2892 NOTE 3--Caution: The followingthree steps should not be done until after the first naphtha cut has been removed to assure that all the light gases have been recovered.

allow the vapor temperature to exceed 210"C nor the temperature of the boiling liquid to exceed 310*C. 9.3.9 Shut off the reflux valve and the heating system. Allow the contents to cool to such a temperature that the distillation can be commenced at 13.3 kPa (100 mm Hg) without flooding. This temperature can be estimated by adding the AT between the liquid and vapor temperatures found for the column during atmospheric operation to the expected initial vapor temperature at the reduced pressure, or by subtracting the £xT from the last recorded liquid temperature.

9.2.9 Remove and weigh the dry ice traps containing light hydrocarbon liquid after carefully wiping them dry. 9.2.10 Sample the contents of the first dry ice trap using a 10 to 50 mL pressure vessel evacuated to no lower than 26.6 kPa (200 mm Hg). Keep all containers at the temperature of dry ice to ensure no loss of volatiles. The first trap next to the condenser should contain all of the sample. If condensate is found in the second trap, sample both traps or else combine the contents before sampling. 9.2.11 Submit the trap sample and gas balloon, if used, for analysis by Test Method D 2427 to be reported on a fixed-gas free basis. 9.3 Distillation at Atmospheric Pressure: 9.3.1 Maintain a temperature below -20°C in the lines of the distillate cooler and receiver as well as in the condenser. Turn on the column mantle heat controller and maintain the column jacket temperature 0 to 5"C below the vapor temperature. 9.3.2 Regulate the heat input as necessary to establish and maintain a boilup rate approximately 75 % of maximum. Figs. 3 and 4 can be used as a guide for Propak. Rates for other sizes can be estimated by multiplying the boilup rate in Table 1 by the cross-sectional area of the column and dividing by the sum of the reflux ratio + 1. 9.3.3 Commence takeoff at a reflux ratio of 5:1 and total cycle time between 20 and 30 s. 9.3.4 Take off distillate in separate and consecutive fractions of suitable size. The recommended size of fraction is that corresponding to 5 or 10*C in vapor temperature. Collect fractions boiling below 65"C in receivers cooled to 0*C or below. When the vapor temperature reaches 65"C, refrigerant in the condenser and related coolers can be discontinued and water at ambient temperature substituted. 9.3.5 At the end of each fraction and at each cut point, record the following observations: 9.3.5.1 Time in hours and minutes, 9.3.5.2 Volume in millilitres, 9.3.5.3 Vapor temperature in *C to the nearest 0.5"C, 9.3.5.4 Temperature of the boiling liquid in *C to the nearest I'C, 9.3.5.5 Atmospheric pressure in kPa (mm Hg), and 9.3.5.6 Pressure drop in the column in kPa (mm Hg). 9.3.6 If significant water is encountered in the condenser or the receiver (greater than 0.1% of the charge), follow the procedure outlined in Annex A8 to dry the sample before continuing the distillation. 9.3.7 If signs of flooding are observed, reduce the heating rate while continuing takeoff until steady conditions are restored. Ifa cut point is encountered during this period, stop the distillation, cool the charge and recombine the offcondition cuts. Restart the distillation with a period at total reflux, not to exceed 15 min, to restore operating conditions before continuing takeoff. Do not make a cut within 5"C of startup. 9.3.8 Continue taking cuts until the desired maximum vapor temperature is reached or until the charge shows signs of cracking. Pronounced cracking is evidenced by a fog appearing in the flask and later at the reflux divider. Do not

Note 4--Cooling of the liquid in the flask can be accelerated by blowing a gentle stream of compressedair onto the flask atter its heating mantle has been removed. Avoid strongjets of cold air. Alternately,turn on coolant in the quench coil of the flask, if used. 9.3.10 Weigh all fractions and determine their densities. 9.3.11 Submit the first distillate fraction for analysis by gas chromatography. 9.4 Distillation at 13.3 kPa (100 mm Hg): 9.4.1 If further cuts at higher temperatures are required, distillation can be continued at reduced pressures, subject to the maximum temperature that the boiling liquid will stand without significant cracking. This is about 310"C in most cases. Notable exceptions are crude oils containing heatsensitive sulfur compounds. In any case, do not make a cut within 5"C of the temperature at startup because the column will not be at equilibrium. 9.4.2 Connect a vacuum pumping and control system to the apparatus as shown in Fig. 1. 9.4.3 Start the vacuum pump and adjust the pressure downward gradually to the value of 13.3 kPa (100 mm Hg) or set the pressure regulator at this value. The temperature of the liquid in the flask must be below that at which it will boil at 13.3 kPa (100 mm Hg). If the liquid boils before this pressure is reached, increase the pressure and cool further until the desired pressure can be achieved without boiling. 9.4.4 Apply heat to the boiler and reestablish reflux at any moderate rate in the reflux divider for about 15 min to reheat the column to operating temperature. Momentarily stop heat input and raise the pressure with N2 for 1 min to drop the holdup into the distillation flask. 9.4.5 Reapply heat to the distillation flask and adjust the rate of heating to maintain a constant pressure drop equivalent to the boilup rate of approximately 75 % of the maximum rate for this pressure and begin takeoff without delay. The approximate pressure drops required for this purpose are indicated in Fig. 3. Maintain a column insulation temperature 0 to 5"C below the vapor temperature throughout the operation. 9.4.6 Remove separately, cuts of suitable size as in 9.3.4. 9.4.7 At the end of each distillate fraction and at each cut point, record the following observations: 9.4.7.1 Time in hours and minutes, 9.4.7.2 Volume in millilitres observed at ambient temperature, 9.4.7.3 Vapor temperature in *C to the nearest 0.5"C with correction, if any, 9.4.7.4 Temperature of the boiling liquid in *C to the nearest I'C, 9.4.7.5 Pressure drop in the column in kPa (mm Hg), 9.4.7.6 Operating pressure measured at the top of the 461

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9.4.9 Shut off the reflux valve and the heating system. Allow the contents to cool to such a temperature that the distillation can be commenced at a lower pressure without boiling. This temperature can be estimated by adding the AT between the liquid and vapor temperatures found for the column during operation to the expected initial vapor temperature at the lower pressure, or by subtracting the AT from the last recorded liquid temperature. 9.4.10 Weigh all fractions and determine their densities at 15"C. 9.5 Distillation at Lower Pressures: 9.5. I If the final cut point has not been reached, distillation can be continued at a lower pressure subject to the same limitation as before (9.4.1). Only one pressure level between 13.3 kPa (100 mm Hg) and 0.266 kPa (2 mm Hg) is permitted. Where the maximum cut point is 400"C AET, the minimum pressure is recommended. 9.5.2 Adjust the pressure to the desired level. If the liquid boils before the pressure is reached, increase the pressure and cool further until the desired pressure can be achieved without boiling. Follow the procedure in 9.4.4. 9.5.3 Circulate cooling water in the condenser and liquid cooler either at ambient temperature or warmed to a temperature that will ensure that wax does not crystallize in the condenser or takeoff lines. Alternatively, leave the cooling coils full of water but vented and not circulating, or else circulate a stream of air instead of water as a coolant. 9.5.4 Continue vacuum operation as in 9.4.5 through 9.4.8. During this operation, a reflux ratio of 2:1 is allowed if mutually agreed upon in advance and noted in the report. Convert observed and corrected vapor temperatures to atmospheric equivalents using Tables 4 or 5 or Annex A9. Fig. 5 is provided only as a guide in estimating the cut points during distillation. 9.5.5 Check periodically that the condensate drips normally in the condenser and that the distillate flows smoothly into the takeoff line. If crystallization is observed, allow the coolant in the condenser to warm as in 9.5.3. 9.5.6 When the final cut point has been reached, or when limits of boiling liquid temperature and column pressure

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OPERATING PRESSURE,kPa

FIG, 3

Expected T a k e o f f Rates at 5:1 Reflux Ratio for Fractionatore Using Prepak

column in kPa (mm Hg) absolute with correction, if any, and 9.4.7.7 Atmospheric Equivalent Temperature (AET) using Table 3. If AET cannot be obtained from Table 3, it must be calculated from the equation in Annex A9. Figure 5 is provided only as a guide in estimating the cut points during distillation. 9.4.8 Continue taking cuts until the desired maximum point is reached or until the charge shows signs of cracking. Pronounced cracking is evidenced by the evolution of gases as indicated by rising pressure as well as a fog appearing in the flask (Note 4). Do not allow the temperature of the boiling liquid to exceed 310*C. NOTE 5 - - C a u t i o n : A u t o m a t i c v a c u u m c o n t r o l l e r s c o u l d m a s k a slight rise i n p r e s s u r e d u e t o c r a c k i n g . V i g i l a n c e is r e q u i r e d t o a v o i d this.

TABLE 3

Conversion of Temperatures to Atmospheric Equivalent from Measurements st 13.3 kPa (100 mm Hg)

Temperature, °C

0

1

2

3

4

5

6

7

8

9

50 60 70 80 90 1O0 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250

108.5 119.9 131.3 142.6 153.9 155.1 176.4 187.6 198.8 210.0 221.1 232.2 243.3 254.4 265.4 276.5 287.5 298.4 309.4 320.3 331.2

109.7 121.0 132.4 143.7 155.0 166.3 177.5 188.7 199.9 211.1 223.2 233.3 244.4 255.5 266.5 277.6 288.5 299.5 310.5 321.4 332.3

110.8 122.2 133.5 144.8 156.1 167.4 178.6 189.8 201.0 212.2 223.3 234.4 245.5 256.6 267.6 278.7 289.6 300.6 311.6 322.5 333.4

112.0 123.3 134.7 146.0 157.2 168.5 179.7 191.0 202.1 213.3 224.4 235.6 246.6 257.7 268.7 279.8 290.7 301.7 312.7 323.6 334.5

113.1 124.4 135.8 147.1 158.4 169.6 180.9 192.1 203.3 214.4 225.6 236.7 247.7 258.8 269.8 280.9 291.8 302.8 313.7 324.7 335.6

114.2 125.6 136.9 148.2 159.5 170.8 182.0 193.2 204.4 215.5 226.7 237.8 248.9 259.9 270.9 282.0 292.9 303.9 314.8 325.8 336.6

115.4 126.7 138.0 149.4 160.6 171.9 183.1 194.3 205.5 216.6 227.8 238.9 250.0 261.0 272.0 283.1 294.0 305.0 315.9 326.8 337.7

116.5 127.9 139.2 150.5 161.8 173.0 164.2 195.4 206.6 217.8 228.9 240.0 251.1 262.1 273.2 264.2 295.1 306.1 317.0 327.9 338.8

117.6 129.0 140.3 151.6 162.9 174.1 185.4 196.6 207.7 218.9 230.0 241.1 252.2 263.2 274.3 285.3 296.2 307.2 318.1 329.0 339.9

118.8 130.1 141.4 152.7 164.0 175.3 186.5 197.7 208.8 220.0 231.1 242.2 253.3 264.3 275.4 286.4 297.2 308.6 319.2 330.1 341.0

462

i1~ D 2892 50

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250

TEMPERATURE, C FIG. 4

Vapor Correction Chart

prevent further distillation, turn off the reflux valve and heating system and allow to cool with the vacuum still applied. 9.5.7 When the temperature of the residue in the flask has fallen below 230"C, shut off the vacuum pump. Vent the fractionating unit with nitrogen or other inert gas. Do not use air. NOT~ 6--Caution: Air is suspected of initiating explosions in fractionating units that are vented while too hot, such as at the end of a run. 9.5.8 Stop circulation of coolant in the condenser and ancillary equipment. Disconnect the flask. Recover the static holdup of the column (wettage) by distilling a small quantity TABLE 4

of solvent such as toluene in a separate flask to wash the column, condenser, and takeoff system. Evaporate the solvent from the collected residue at 10°C above the boiling point of the solvent, using a small purge of nitrogen. For distillations not involving disagreement, or by mutual consent, the holdup can be estimated using a graph similar to Fig. 5. The density of the holdup is estimated by extrapolation of the density line for the preceding cuts. The static holdup can be treated as a separate small cut or blended into the bottoms before inspections are made. The latter must be done if other analyses besides density are to be performed on

Conversion of Temperatures to Atmospheric Equivalent from Measurements at 1.33 kPa (10 mm Hg)

Temperature, oC

0

1

2

3

4

5

6

7

8

9

50 60 70 80 90 1O0 110 120 130 140 160 170 180 190 200 210 220 230 240

165.8 178,4 190.9 203.4 215.8 228.1 240.4 252.7 264.9 277.0 289.2 301.2 313.2 325.1 337.0 348.8 360.6 372.3 384.0 395.7

167.1 179.6 192.1 204.6 217.0 229.4 241.7 253.9 266.1 278.3 290.3 302.4 314.4 326.3 338.2 350.0 361.8 373.5 385.2 396.8

168.3 180.9 193.4 205.9 218.3 230.6 242.9 255.1 267.3 279.5 291.5 303.6 315.6 327.5 339.4 351.2 363.0 374.7 386.4 398.0

169.6 182.1 194.6 207.1 219.5 231.8 244.1 256.4 268.5 280.7 292.8 304.8 316,8 328.7 340.5 352.4 364.1 375.9 387.5 399.1

170.8 183.4 195.9 208.3 220.7 233.1 245.4 257.6 269.8 261.9 294.0 306.0 317.9 329.9 341.7 353.5 365.3 377.0 388.7 400.3

172.1 184.6 197.1 209.6 222.0 234.3 246.6 258.8 271.0 283.1 295.2 307.2 319.1 331.1 342.9 354.7 366.5 378.2 389.8 401.5

173.3 185.9 198.4 210.8 223,2 235.5 247.8 260,0 272.2 284.3 296.4 308.4 320.3 332.2 344.1 355.9 367.7 379.4 391.0 402.6

174.6 187.1 199.6 212.1 224.4 236.8 249.0 261.2 273.4 285.5 297.6 309.6 321.5 333.4 345.3 357.1 368.8 380.5 392.2 403.8

175.9 188.4 200.9 213.3 225.7 238.0 250.3 262.5 274.6 286.7 298.8 310.8 322.7 334.6 346.5 358.3 370.0 381.7 393.3 404.9

177.1 189.6 202.1 214.5 226.9 239.2 251.5 263.7 275.8 287.9 300.0 312.0 323.9 335.8 347.6 359.4 371.2 382.9 394.5 406.1

250

407.2

408.4

409.6

410.7

411.9

413.0

414.2

415.3

416.5

417.6

150

463

~ TABLE 5 Temperature,

D 2892

Conversion of Temperatures to Atmospheric Equivalent from Measurements at 0.266 kPa (2 mm Hg)

°C

0

1

2

3

4

5

6

7

8

9

50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250

201.1 214.4 227.6 240.7 253.7 266.7 279,5 292.4 305.1 317.8 330.4 342.9 355.4 387.8 380.1 392,3 404.5 416.6 428.7 440.7 452.6

202.4 215.7 228.9 242.0 255.0 268.0 280.8 293.6 306.4 319.0 331.6 344.2 356.6 369.0 381.3 393.5 405,7 417.8 429.9 441.8 453.8

203.8 217,0 230.2 243.3 256.3 269.2 282.1 294.9 307.6 320.3 332.9 345.4 357.8 370,2 382.5 394.8 406.9 419.0 431.1 443.0 454.9

205.1 218.3 231.5 244.6 257,6 270.5 283.4 296.2 308.9 321.6

206.4 219.6 232.8 245.9 258.9 271.8 284.7 297.5 310.2 322.8 335.4 347.9 360.3 372.7 385.0 397.2 409.4 421.4 433.5 445.4 457.3

207.7 221.0 234.1 247.2 260.2 273.1 286.0 298.7 311.5 324.1 336.8 349.1 381.6 373.9 386.2 398,4 410.6 422.7 434.7 446.6 458.5

209.1 222.3 235.4 248.5 261.5 274.4 287.2 300.0 312.7 325.3 337.9 350.4 362.8 375.2 387.4 399.6 411.8 423.9 435.9 447.8 459.7

210.4 223.8 236.7 249.8 262.8 275.7 288.5 301.3 314.0 326.6 339.2 351.6 364.0 376.4 388.7 400.9 413.0 425.1 437.1 449.0 460,9

211.7 224.9 238,0 251.1 264.1 277.0 289.8 302.6 315.2 327.9 340.4 352.9 365.3 377.8 389.9 402.1 414.2 426,3 438.3 450.2 462.1

218.0 226,2 239.4 252.4 265.4 278.3 291.1 303.8 316.5 329.1 341.7 354,1 366.5 378.8 391.1 403.3 415.4 427.5 439.5 451.4 463.2

334.1 346,6 359.1 371.5 383.8 396.0 408.1 420,2 432.3 444.2 456.1

the residue. 9.5.9 Weigh all fractions and the residue in the flask and determine their densities at 15°C by Test Method D 4052 or by another suitable method. Convert the density to 15°C, if necessary.

V = (M/D)

(3)

where: D = density of charge at 15"C, g/mL M = mass of dry charge, g V = volume of charge, mL. 10.4 Calculate the volume of each fraction and of the residue in milliliters at 15"C using Eq 4.

NOTE 7--Heavier flasks such as those for 50 and 70 mm diameter columns are not normally removed for weighing. In these cases the residue can be discharged at a temperature not over 200"C into a tared container for weighing. Nitrogen pressure of approximately 6.7 kPa (50 mm Hg) will be sufficient for this. Wettage in these cases will include that of the column and the flask together.

v = m/d

(4)

where: d = density of the fraction or residue at 15°C, g/mL m -- mass of fraction or residue corrected for loss, g v -- volume of fraction, mL. 10.5 Calculate the volume percent of each distillate fraction to the nearest 0.1 vol-% using Eq 5.

10. C a l c u l a t i o n 10.1 Calculate the mass-percent of each distillate fraction and the residue to the 0.1 mass- % using Eq 1. mass-% = lO0(m/M) (1) where: m -- mass of fraction or residue, g M = mass of dry crude oil charged, g. 10.1. I The first fraction is the gas fraction collected in the balloon. If this fraction is less than 0.1 mass-%, it can be ignored. 10.1.2 The second fraction (or first, if no gas is collected) is the condensate in the dry ice trap. With density at 15"C calculated from the gas chromatographic data on a fixed gas free basis, its volume can be computed. 10.1.3 The holdup is treated either as a separate cut or added to the residue fraction, according to agreement. The amount of holdup is determined by actual recovery by solvent washing, as directed in 9.5.8, or estimated from Fig. 6. 10.2 Calculate the percent loss to the nearest 0.1 mass-% using Eq 2. Loss = 100 - (Z lO0(m/M)) (2)

vol-% = 100(v/V)

(5)

10.6 Calculate the volume percent gain or loss to the nearest 0.1 vol-% using Eq 6. Loss = 100 - (Zl00(v/V)) (6) Usually, the above expression is negative due to volume ex pansion. Normalize any apparent expansion or contraction among fractions boiling below 150"C in proportion to their yields. NOTE 8Din view of the foregoing rules for establishing yields, the

ratio of mass to volume is not precise enough to be used to calculate the density of any distillate fractions or residue. 11. R e p o r t I I. 1 A summary sheet for the run must include: 11.1.1 The mass of the dry sample charged, g, 1 I. 1.2 The density of the sample at 150C, g/mL, 11.1.3 The volume of the sample at 15°C, mL, 11.1.4 The gain or loss in mass and volume to the nearest 0.I %, 11.1.5 The volume and mass percents of each fraction to the nearest 0.1%, I I. 1.6 The cumulative.volume and mass percentages, and 11.1.7 The mass of water, if any. 11.2 The gas, debutanized naphtha and succeeding fractions are listed in order of ascending boiling point with

The weight loss as calculated above must not be greater than 0.4 %, otherwise the distillation must be discarded. Losses less than this should be allocated two thirds to the trap cut and one third to the first naphtha cut. Where there is no trap cut, the acceptable losses are to be normalized among all cuts. 10.3 Calculate the volume of the sample of crude oil in milliliters at 15"C using Eq 3. 464

1{~ D 2892 15

i0

._J

f 150 FIG. 5

200

25O 3O0 CUT TEMPERATURE *C AET

35O

4OO

Approximate Static Holdup for Average Crude Oil Using 4 mm Propak In a 25-mm ID x 570-mm Column

residue recorded last. 11.3 The observations made in 9.3.5, 9.4.7, and 9.5.4 are included as a second sheet which is normally attached to the summary sheet. 11.4 Make plots of the temperature in degrees Celsius AET as the ordinate (y--axis) versus the percentage mass and volume distilled as the abscissa (x--axis). These are the final TBP distillation curves.

and independent results obtained by different operators working in different laboratories on identical test material would in the normal and correct operation of this test method, exceed the values indicated below in one case in twenty. Atmosphedc pressure Vacuum pressure

mass-% 1.2 1.4

vol-% 1.2 1.5

12.4 Bias 12.4.1 Absolute Bias--Since there is no accepted reference material suitable for determining the bias for the procedure in Test Method D 2892 in determining distillation properties of crude petroleum, bias cannot be determined. 12.4.2 Relative Bias--TBP (True Boiling Point) is defined under the conditions of this Test Method (1.2). NOTE 9--The crude oil used for this precision statement had a density at 15°C equal to 0.859 and an average slope equal to 6°C per percent distilled.

12. Precision and Bias 12.1 The precision of the method as determined by the statistical examination of interlaboratory test results is described below. 12.2 Repeatability--The difference between successive results obtained by the same operator with the same apparatus under constant operating conditions on identical test material would, in the long run, in the normal and correct operation of this test method, exceed the values indicated below in one case in twenty. (Repeatability is under statistical review.) 12.3 Reproducibility--The difference between two single

13. Keywords 13.1 crude oil distillation; distillation; fractional distillation; TBP curves; boiling point distillation 465

~

D 2892

ANNEXES

(Mandatory Information) AI. TEST M E T H O D FOR T H E D E T E R M I N A T I O N OF T H E EFFICIENCY OF A DISTILLATION C O L U M N AI.1 Scope A I.I.I This test method is for determining the efficiency of a distillation column, under total reflux conditions using the test mixture n-heptane/methylcyclohexane at atmospheric pressure. Al.I.2 The efficiency is not measured under vacuum conditions because there is no satisfactory test mixture that has a constant relative volatility with pressure.

AI.2 Significance and Use A I.2.1 The efficiency of the distillation column must be between 14 and 18 theoretical plates to be used in Test Method D 2892 (6.1.3.2). A1.2.2 The performance of particulate packings is well established in the literature. The data shown in Table 1 can be used in place of this test method. A1.3 Apparatus A1.3.1 An example of a suitable apparatus is shown in Fig. A 1.1. It consists of the following: A1.3.1.1 Calibration Flask, of suitable size with a device for heating. An example of a suitable calibration flask is shown in Fig. A I.2. A I.3.1.2 Distillation Column and Condenser. A1.3.1.3 Manometer, or equivalent to measure the pressure drop in the column.

with air while still hot. To keep the apparatus completely dry, connect a moisture trap at the vent of the overhead condenser.

A1.6 Procedure A I.6.1 Introduce into the distillation flask a quantity of test mixture equal to the minimum volume permitted for the column (see Table l) but not more than two thirds of the capacity of the flask. Add some pieces of glass or porcelain to promote even boiling. AI.6.2 Connect the flask to the pressure drop manometer as shown in Fig. A1. I. AI.6.3 Circulate water at ambient temperature in the condenser. A 1.6.4 Apply heat to the flask until the test mixture boils, then increase thc heat progressively up to the flood point. This will be noted by visible slugs of liquid in the packing or on the plates or by liquid filling the neck of the condenser and a sudden increase in pressure drop. Reduce heat to allow the flooding to subside. Increase the heat gradually to just below the flood point. Record boilup and AP measurements just below the flood point. This is considered the maximum rate.

CONDENSER

AI.4 Reagents and Materials

DETERMINATION EFFICIENCY

r~--~

AI.4.1 The test mixture is a 50/50 mixture by volume of n-heptane and methylcyclohexane with refractive indexes of: =

n-heptane

nD 20

methylcyclohexanc

nD 2° = 1 . 4 2 3 1 2

1.38764

A1.4.2 Chromatographic analysis of the components of the test mixture must show less than 0.01% contamination with lighter compounds and greater than 99.75 % purity. They must be transparent to ultraviolet light at 260 to 270 nm to ensure freedom from aromatics. AI.4.3 If the components do not meet the above specification, they can be purified either by redistillation in a 30 to 50 plate column, or by percolation through 200-mesh silica gel, discarding the first 10 % of the cluted liquid. Exercise care that the gel does not become overloaded.

~:=VE.T TOWER&JACKET i COLLECTOR

CONTROL BAROMETEF

A1.5 Preparation of Apparatus

NITROGEN BUBBLER

AI.5.1 The distillation column and all the glassware must be clean and dry before proceeding with the test described. Cleaning can be accomplished by washing with a strong industrial detergent. Rinse thoroughly, dry and reassemble. AI.5.2 Distill a small quantity of pure n-heptane at a high boilup rate for at least 5 min. Take off several small quantities through the overhead sampling system at intervals. Turn offthe heat, remove the flask, and dry the column

~

REFLUX

SAMPLE

CALIBRATIONFLASH (See FIG 2)

FIG. A1.1

466

Determination of Efficiency

(~ D 2892 A1.6.5 Adjust the heat input until the column is refluxing at a steady rate corresponding to about 200 mL/h times the cross-sectional area of the column in cm 2. A1.6.6 Maintain the column under total reflux for 1 h. Record the pressure drop and determine the boilup rate by timing the filling of the calibrated bulb. AI.6.7 Take rapidly and almost simultaneously, a sample of the flask liquid and reflux in sufficient quantity for the determination of the refractive indexes at 20"C but not more than 0.5 mL each. The duration of withdrawal of the reflux sample must not exceed 2 s. A1.6.8 Measure refractive indexes of reflux and flask samples. A1.6.9 Repeat AI.6.7 and A1.6.8 at intervals of 12 to 30 rain until refractive index measurements indicate that steady conditions of maximum efficiency have been attained. A1.6.10 Check the ultraviolet absorption of the flask sample at 260 and 270 nm. If an absorption is detected, aromatics contamination is present and the efficiency determination will be in error. The apparatus must be cleaned and the test mixture repercolated through fresh silica gel before starting over. A1.6.11 Repeat successively, the series of operations A 1.6.5 to A1.6.10 without preflooding, at four or more other boilup rates approximately equally spaced between (200 mL/h) x cm 2 and the maximum rate. One of these should be at a rate that is above 90 % of maximum.

TO FIT TC4JERo--~.

Refractive Index

0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00

1.4231 1.4191 1.4151 1.4113 1.4076 1.4040 1.4005 1.3971 1.3939 1.3907 1.3876

CAPILLARY STOPCOCK--

L|(~4JID $ A H P k Z ~ "/UBE.

xo

N=

log

1 --X D

log a

- 1

.

FIG. A1.2

.

.

.

.

ROUNO BOl'r0H FLASK

Boiling Rate Timer

libria have been determined by Adler et al. 6 and relative volatility is taken as 1.075 as recommended by IUPAC 7. A1.7.4 The efficiency of the column is numerically equal to the difference between the plate numbers indicated on the curve for top and bottom samples. Note that one plate is subtracted for the contribution of the flask, or alternatively a sample of liquid from the bottom of the column rather than the flask can be taken to obtain the efficiency of the column alone. A1.7.5 For packed columns, draw curves of HETP in mm, AP in kPa and kPa/m, and number of theoretical plates as a function of boilup rate expressed in mL/h and absolute rate in (mL/h) x cm 2. For real plate columns, the efficiency should be plotted as percent of a theoretical plate per real plate and AP should be plotted both in kPa/real plate and in absolute units of kPa/theoretical plate using the same units for boilup rate as above for packed columns. The efficiency of the column corresponds to the value of N determined from the curve at 75 % of its maximum boilup rate. A 1.7.6 Typical curves for the popular packings and plate columns are shown in Figs. A 1.4 to A 1.7. These columns are to be used in the unpreflooded condition. Data on other packings are inconclusive or incomplete in the literature and are not included. A1.7.7 Draw a vertical line on the graph at 75 % of maximum boilup and read the HETP or the plate efficiency corresponding to this rate. A1.7.8 Multiply the HETP in millimeters by 14 and by 18 for packed columns to obtain the range of permissible heights of packing for use in this standard. If the efficiency of a packed column is greater than 18 plates as measured above, the efficiency can be reduced by removing a suitable amount of packing without detriment to performance. AI.7.9 For real plate columns, divide 14 and 18 by plate efficiency to obtain the number of actual plates (rounded to the nearest integer) for an acceptable column.

Xo 1 --X o

- - 3 ~tAY T'-80RE 3 mm COCK

SUITABLE $ Z

AI.7.2 Calculate the number of theoretical plates in the column by means of the Fenske equation 5 [AI. 1]: log - -

-0[LTA P CONNECTTON

----C~LISAAT~D BULB

A1.7 Calculation A I.7.1 For each pair of samples taken, determine the molar composition of each sample by comparison of its refractive index with a curve of refractive index versus molar composition of n-heptane drawn from the following data: Molar fraction of n-heptane

~

(Al.l)

where: N = number of theoretical plates in the column, o~ = relative volatility of n-heptane to methylcyclohexane, XD = molar fraction of n-heptane in the reflux liquid, and )Co = molar fraction of n-heptane in the flask liquid. A1.7.3 Fig. A1.3 is a graphical solution to the equation for the n-heptane-methylcyclohexane binary. Vapor-liquid equi-

A1.8 Precision and Bias

AI.8.1 No statement is made concerning either the preciAdler, et al., American Institute of Chemical Engineers, Vol 12, 1966, p. 629. 7 Seig, Chemie-lngenieur-Tecknik, Vol 22, 1950, p. 322.

s A more convenient form of the equation from: Fenske, M. R., Industrial and

Engineering Chemistry, Vol 24, 1932, p. 482.

467

~)

D 2892

ii |FRACIIVm[ INDEX

FIG. A1.3 Refractive Index

SO,

I 3

25

~.0 -i ~0

2O

a. 2./

.o m c~

|

a.

2o

'n"5

10 02

2~ FIG.

A1.4

,~ 4 mm

B011.1iP , t l , e

Propak

600

v cm'

in 25-ram

800

Inside D i a m e t e r T o w e r s

whether there is conformance to the criteria stated in Test Method D 2892.

sion or bias of Annex A I for measuring the efficiency of a distillation column because the result is used to determine

468

(1~') D 2892 1,5 50

1 2

40 , 20 1.0

3O a. 20

N

0.7 i

15

0.5

;0 0.2

2~o

6o~

4oh

.o6

dOILUP .L/.e x c.~

FIG. A1.5

4 mm Propak in 50-mm Inside Diameter Towers

"1.5

/

~

.._~,tt Ir

/

1.3

/

1 0

z o.

0.7 w 0.5 10

0.2

0

i00

"

¢I%ILIJP ,lJ',m x c~Z

FIG. A1.6

60o

6 mm Propak in 50-ram Towers

469

1@) O 2892 l.S

1.Z

1.0

Ap(

0.7

0.S

0.2 HOL~UP (~)

~i~

~bo

BOILUP PwJ.i x c~Z

~

800

NOTE--.-(1) Analytical Chemistry, ANCHA, Vol 39, 1967, p. 286. (2) Exxon unpublished data.

FIG. A1.7

Perforated Plates 50-ram Inside Diameter

~

D 2892

A2. T E S T M E T H O D FOR T H E D E T E R M I N A T I O N OF T H E DYNAMIC H O L D U P OF A DISTILLATION COLUMN A2.1 Scope A2.1.1 This test method is for determining the dynamic holdup of a distillation column using a test mixture of stearic acid in n-heptane.

samples of not more than the amount necessary for a determination, and immediately observe and record the boilup rate and AP. A2.7.8 Analyze the reflux and flask samples to determine the concentration of stearic acid in mass-percent (P). A2.7.9 Repeat A2.7.7 and A2.7.8 at 15 min intervals until the concentration of stearic acid in the flask sample is steady. A2.7.10 Raise the boilup rate by an additional 200 (mL/h) x cm 2 and repeat A2.7.7 to A2.7.9. A2.7.11 Continue making measurements as above at increments of about 200 (mL/h) x cm 2 until near the flood point. At least four sets of measurements should be obtained including one near the maximum operable rate.

A2.2 Summary of Test Method A2.2.1 A test mixture, composed of stearic acid in nheptane is distilled under total reflux conditions. From the difference in concentration of stearic acid in the initial mixture and in the mixture during refluxing, the dynamic holdup of the column is calculated. A2.3 Significance and Use A2.3.1 The amount of sample charged to a particular distillation column must be of such a size that the dynamic holdup of that column is between 2 and 4 % of that charge size at 75 % boilup rate (9.1.1). A2.3.2 The performance of the particle packings is well enough defined in the literature that the data in Table 1 can be used instead of this test method.

A2.8 Calculation A2.8.1 Calculate the dynamic holdup of the column for each observation using Eq A2.1:

P-Po

H=~

P

M

x -d

(A2.1)

where: H -- dynamic holdup in column, mLs at 15"C, M = mass of test mixture in the flask, g, Po = stearic acid in the test mixture initially, mass-%, P = stearic acid in the test mixture after distillation, mass-%, and d = density of n-heptane, 0.688 glmL at 15"C. A2.8.2 Calculate the dynamic holdup per theoretical plate at each rate of boilup at which the determination was made using Eq A2.2: H h=~ (A2.2)

A2.4 Apparatus A2.4.1 The apparatus is identical to that described in A1.3, Fig AI. 1. A2.5 Reagents and Materials A2.5.1 The test mixture consists of 20 mass-% stearic acid in n-heptane. The n-heptane shall have a refractive index at 20"C of 1.3878 _+ 0.0002. The stearic acid shall be greater than 95 % pure and have a melting point of 68 to 70"C. A2.6 Preparation of Apparatus A2.6.1 See AI.5.

where: N = efficiency in theoretical plates of the column under total reflux at this boilup rate (see Annex A 1). A2.8.3 Convert the boilup measurement in litres per hour to rates per hour in (mL/h) x cm 2. Convert also the AP measurements to kPa/m (mm Hg/m) and the holdup measurement to milliliters per theoretical plate. A2.8.4 Plot all data as ordinates versus boilup rate in litres per hour and (mL/h) x cm 2 as abscissa. Draw smooth curves through the points for holdup in millilitres and in millilitres per theoretical plate. The boilup versus AP measurements should be compared with those made in the efficiency measurements if available, to ensure that they are in reasonable agreement. A2.8.5 Draw a vertical line at 75 % of maximum boilup rate. The dynamic holdup for the column will be that read from the intersection of the holdup curve and the line for 75 % of maximum boilup rate. The charge size, ranging from a holdup ratio of 2 to 4 % will thus be from 50 to 25 times the above figure.

A2.7 Procedure A2.7.1 Measure the concentration of stearic acid in the test mixture by a convenient means. For example, titrate with 0.1 N NaOH solution to a pH of 9.0 potentiometrically. Record the results as mass-percent stearic acid (Po). A2.7.2 Introduce pieces of glass or porcelain into the flask or use a good stirrer to promote even boiling. A2.7.3 Add 1 L of the test mixture for a 25-mm inside diameter column or 4 L for a 50-mm column to the flask. Weigh the flask to the nearest 1 g. A2.7.4 Attach the flask to the distillation column and to the AP measuring system. A2.7.5 Circulate water at ambient temperature through the condenser. A2.7.6 Apply heat to the flask and bring the test mixture to a boil. Adjust the boilup rate to approximately 200 mL/h times the cross-sectional area of the column in cm 2 measured by timing the filling of the calibrated bulb. When the desired rate has been established, hold for 30 min noting the pressure drop. A2.7.7 Sample the reflux and the flask liquids, taking

A2.9 Precision and Bias A2.9.1 No statement is made concerning either the preci471

~

D 2892

sion or bias of Annex A2 for measuring dynamic holdup because the result is used to determine whether there is

conformance to the criteria stated in Test Method D 2892.

A3. TEST M E T H O D FOR T H E D E T E R M I N A T I O N OF T H E H E A T LOSS IN A DISTILLATION C O L U M N (STATIC CONDITIONS) A3.1 Scope A3.1.1 This test method is for determining the heat loss of a distillation column under static conditions when a temperature differential exists between the inner and outer walls of a distillation column.

A3.5 Preparation of Apparatus A3.5.1 The heat sensor location, response time, and calibration must be checked as specified in Annexes A4 to A6. A3.5.2 To reduce chimney effects inside the column during the test, the top of the condenser must be closed.

A3.2 Summary of Test Method A3.2.1 The outer wall of the column vacuum jacket is maintained at an elevated constant temperature. The temperature increase inside the column, as recorded by the sensor in the reflux divider, is a measure of the heat gained and thus heat lost by the column.

A3.6 Procedure A3.6.1 Record the time and ambient temperature. A3.6.2 Apply heat to the outer wall of the column vacuum jacket. Adjust the heat progressively until the temperature sensor located on the column wall records a temperature 100"C above ambient. This condition provides a suitable temperature difference to measure without placing unnecessary thermal strain on the glassware. Attain the 100*C differential temperature within 30 min and maintain the column at this temperature for 1 h. A3.6.3 Record the time, the temperature of column outer wall, and the temperature inside the column.

A3.3 Significance and Use A3.3.1 It is important to have an effective silvered glass vacuum jacket surrounding the column and reflux divider. This reduces the effects of ambient air temperature near the distillation apparatus and promotes easier control at the maximum distillation temperatures. The use of a heat compensating mantle further reduces losses by reducing the temperature gradient between inside of the column and the ambient air. A3.3.2 The test should be performed on all new glass vacuum jackets before use, and checked at least once per year thereafter. A3.3.3 The heat loss as determined by this test method must be less than 30 % for the column to be acceptable for use in Test Method D 2892.

A3.7 Calculation A3.7.1 Calculate the heat gained and thus lost by the column using Eq A3.1:

B-A

Q = C - A x 100

(A3.1)

where: A - ambient temperature, °C, B = temperature inside column, °C, and C -- temperature of outer wall, °C. or, when the differential temperature is 100°C, use Eq A3.2:

A3.4 Apparatus A3.4.1 The column is enclosed in its heat compensating mantle with the thermocouple in place on the column wall. A3.4.2 A twin pen chart recorder to monitor the column outer wall and heat sensor temperatures and an automatic proportioning controller for the heat input are recommended.

Q= B- A

(A3.2)

A3.8 Precision and Bias A3.8.1 No statement is made concerning either the precision or bias of Annex A3 for measuring heat loss because the result is used to determine whether there is conformance to the stated criteria (A3.3.3).

A4. T E S T M E T H O D FOR T H E VERIFICATION OF T E M P E R A T U R E SENSOR LOCATION

A4.1 Scope A4.1.1 This test method is for determining whether the temperature sensor is in the proper position for optimum performance.

A4.3 Significance and Use A4.3.1 A poorly positioned sensor can give temperatures that are in error due to inadequate beat supply from the vapors. It is especially important under vacuum when heat content of the vapor is at a minimum. A4.3.2 The procedure is normally performed once only for the approval of a design and need not bc repeated thereafter.

A4.2 Summary of Test Method A4.2.1 The vapor temperature of a pure compound measured by the sensor and its recording instrument is compared to the accepted boiling point for the compound. The test is conducted both at atmospheric pressure and under vacuum of 0.133 kPa (l mm Hg).

A4.4 Procedure A4.4.1 Atmospheric Distillation: A4.4.1.1 Assemble the apparatus for atmospheric distilla472

~) D 2892 tion. Use cooling water at ambient temperature. Charge 0.5 to 1 L of pure, dry n-tetradecane containing less than 0.1% light contaminants as determined by gas chromatography. Calibrate the temperature sensor as prescribed in Annex A6. A4.4.1.2 Apply heat and establish equilibrium at a boilup rate of about 400 (mL/h) x cm 2. This corresponds to a AP of about 0.4 kPa/m (3 mm Hg/m) for particle packing or 0.09 kPa/plate (0.07 mm Hg/plate) for real plate columns. Hold at these conditions for 15 rain. If the vapor temperature drops more than 0.2"C, remove 2 % overhead at 5:1 reflux ratio and then again hold at total reflux for 15 min. Continue taking 2 % cuts as above until the vapor temperature remains steady within 0.2"C for 15 min at total reflux. A4.4.1.3 Record the boiling point to the nearest 0.5°C and the atmospheric pressure to the nearest 0.1 kPa (1 mm Hg), using instruments calibrated in accordance with Annex A6. A4.4.1.4 If the observed boiling point is not 253.5 ± 0.5"C the location of the sensor is suspect and must be corrected before use in this method. A4.4.2 Vacuum Distillation: A4.4.2.1 Assemble the apparatus for vacuum distillation. Charge 0.5 to I L of pure, dry n-hexadecane containing less than 0.1% light contaminants as determined by gas chromatography. Calibrate the temperature and vacuum instruments as prescribed in Annex A6. A4.4.2.2 Reduce the pressure in the system to 0.133 kPa

(1 mm Hg). Circulate air in the condenser to avoid crystallization. A4.4.2.3 Apply heat and establish equilibrium at a boilup rate of between 25 and 50 (mL/h) x cmL This corresponds to a AP of about 0.133 kPa/m (1 mm Hg/m) or less for particle packing or 0.08 kPa/plate (0.06 mm Hg/plate) for real plate columns to 50 mm diameter. Hold at these conditions for 15 min. A4.4.2.4 Remove 2 % overhead at 20:1 reflux ratio and then again hold at total reflux for 5 min. Record the boiling point to the nearest 0.5"C and the operating pressure to the nearest 0.05 kPa (0.3 mm Hg) using instruments calibrated as described in Annex A6. A4.4.2.5 If the observed boiling point is not steady with 0.2"C at 0.133 kPa (1 mm Hg) remove 2 % cuts at 5:1 reflux ratio and then hold at total reflux for 15 min repeating the above until total reflux conditions produce a steady temperature. Not more than three trials should be needed. A4.4.2.6 If the observed boiling point is not 105.2 ± 0.5"C at 0.133 kPa (1 mm Hg), the location of the sensor is suspect and must be corrected before use in this method. A4.5 Precision and Bias A4.5.1 No statement is made concerning either the precision or bias of Annex A4 for checking the location of the temperature sensor because the result is used to determine whether there is conformance to the criteria stated in A4.4.2.6.

473

41~'~ D 2892 A5. T E S T M E T H O D F O R D E T E R M I N A T I O N OF T E M P E R A T U R E R E S P O N S E T I M E A5.1 Scope A5.1.1 This test method is for the determination of temperature response time based upon the rate of cooling of the sensor under prescribed conditions.

range allowing interpolation to 0. l°C. Set the chart speed at 30 cm/h for readability. A5.3.3 Insert the sensor into a hole in the center of one side of a closed cardboard box about 30 cm on a side. Hold the sensor in place by a friction fit on the joint. Allow the sensor to reach equilibrium temperature. Record the temperature when it becomes stable. A5.3.4 Remove the sensor and insert it into the heated thermowell in the beaker of water. After the sensor has reached a temperature of 80"C, remove it and immediately insert it into the hole in the box. Note with a stopwatch, or record on the strip chart, the time interval while the sensor cools from 30°C above to 5°C above the temperature recorded in A5.3.3. A5.3.5 A time interval in excess of 175 s in unacceptable.

A5.2 Significance and Use A5.2.1 This test method is performed to ensure that the sensor is able to respond to changes in temperature fast enough that no error due to lag is introduced in a rapidly rising temperature curve. A5.2.2 The importance of this test is greatest under vacuum conditions when the heat content of the vapors is minimal. A5.3 Procedure A5.3.1 Arrange a 1 L beaker of water on a hot plate with a glass thermowell supported vertically in the water. Maintain the temperature of the water at 90 + 5°C. A5.3.2 Correct the sensor to an instrument, preferably with a digital readout, with readability to 0.1°C. Alternatively, connect the sensor to a strip chart recorder of suitable

A5.4 Precision and Bias A5.4.1 No statement is made concerning either the precision or bias of Annex A5 for measuring temperature response because the result is used to determine whether there is conformance to the criteria stated in A5.3.5.

474

(~1~ D 2 8 9 2

A6. P R A C r l C E FOR CALIBRATION O F SENSORS A6.1 Scope A6.1.1 This practice is for the calibration of temperature sensors and vacuum sensors and their associated recording instruments.

MELTING POINT BATH FOR TEMPERATURE STANDARDS

A6.2. Referenced Document A6.2.1 ASTM Standard." D 1160 Test Method for Distillation of Petroleum Products at Reduced Pressure 3 PURE GRAPHIT(

A6.3 Summary of Practice A6.3.1 The temperature sensor and its associated instrument are calibrated by observing and recording the temperatures of the melting point and boiling point of pure compounds or eutectic mixtures. A6.3.2 The vacuum sensor and its associated instrument are calibrated against a McLeod gage.

FILL TO THIS L(VI[L WITH REAGENT PURITY METAL

8mm I.D

A6.4 Significance and Use A6.4.1 Vapor temperature sensors are calibrated over the full range of temperature at the time of first use of the sensor in combination with its associated instrument. Recalibrate when either the sensor or the instrument is repaired or serviced. In addition, check each vapor temperature sensor once a week at one temperature point that is near a commonly used cut point. The freezing point of tin is recommended. A6.4.2 Another consideration of calibration of temperature measurement is the location of the sensor to ensure its optimum exposure to the saturated vapor at the top of the column (Annex A4).

......

I

ASBESTOS T A P [ ~ WRAPPING TO MAKE CRUCIBLE SNUG FIT INSIDE DEWAR

CRUCIBLE

STANDARD DEWAR FLASK

ELECTRIC

HEATER

METAL FOOT

FIG. A6.1 Melting Point Bath for Temperature Standards become contaminated or excessively oxidized. In this case, replace the metal. A6.6.1.4 Obtain the calibration temperature at each of the following points to the nearest 0.5"C:

A6.5 Apparatus A6.5. I A suitable apparatus is shown in Fig. A6.1. For the freezing point of water, a Dewar flask filled with crushed ice and water can be substituted. For the boiling point of water, use an equilibrium still or ebulliometer, a tensimeter or other apparatus for measuring vapor-liquid equilibrium.

Material

A6.6 Procedure A6.6.1 Temperature Sensors: A6.6.1.1 Ensure that approximately 0.5 mL of silicone oil or other inert liquid is in the bottom of the thermowell and insert one or more thermocouples or other sensors connected to their respective measuring instruments. A6.6.1.2 Heat the melting point bath to a temperature 10*C above the melting point of the metal inside and hold this temperature at least 5 min to ensure that all of the metal is melted. A6.6.1.3 Discontinue heat input to the melting point bath and observe and record the cooling curve. When the curve exhibits a plateau of constant temperature for longer than 1 min, the temperature of the recorded plateau is accepted as the calibration temperature. If the freezing plateau is too short, it can be prolonged by employing some heat during the cooling cycle. Alternatively, the melt bath may have

Temperature, "C

Water Tin: Lead: Cadmium (50:32:18)

melting point boiling point melting point

Sn Pb

melting point melting point

Ice

0.0 100.0 145.0 231.9 327.4

A6.6.1.5 Set up a correction table by listing the correction to be added algebraically to the observed temperature to give the true temperature at each calibration point. A graphical plot of the above corrections connected by a smooth curve may be helpful in routine use. A6.6.2 Vacuum Sensors: A6.6.2.1 For pressures between atmospheric and 13.3 kPa (100 m m Hg), vacuum calibration is based on an evacuated mercury barometer or manometer. For pressures below 13.3 kPa, the McLeod gage is the primary standard and must be carefully calibrated. Secondary gages should be checked at least weekly in routine service or before each use in irregular service. A6.6.2.2 At 13.3 kPa (100 mm Hg), a McLeod gage calibrated for 100 mm Hg can be employed, but an 475

~ /

D 2892

TIP DRAWN UP TO FINE POINT INSIDE. KEEP HEAVY WALL

O D. 50 M, OD IOM

o o

DRILL FRICTION HOLE ART. 0.5 M.M. DIA. FIG. A6.2

Vacuum Manometer

evacuated manometer is simpler and is acceptable. Fig. A6.2

476

shows a convenient design in which any internal air above the mercury is trapped in the fine tip at the top where it can be seen at a glance. For a suitably evacuated gage, there is no air in the tip visible to the unaided eye when vented. The glass must be chemically clean inside. A6.6.2.3 If air can be seen in the tip, clamp the gage in a horizontal position with the vacuum connection facing upward and the top of the gage lower than the bottom so as to expose the hole in the bottom of the central tube. Apply a vacuum of less than 0.0133 kPa (0.1 m m Hg) and heat the end of the gage containing the mercury with an infrared heat lamp or a hot air gun until the mercury comes to its boiling point. Continue heating slowly until the mercury in the central tube has partly distilled out into the outer tube. Condensed mercury on the wall will be evidence of this. Return the manometer to the vertical position and slowly release the vacuum. Verify that there is no air visible at the tip of the central tube when fully vented. A6.6.2.4 At 1.33 kPa (10 mm Hg) and below, assemble a vacuum manifold such as that shown in Fig. A6.3. It must be capable of maintaining steady pressures within __.2 % at all desired levels. A6.6.2.5 Choose a McLeod gage with a range such that the desired calibration pressure falls between 10 % and 90 % of the scale. Heat the McLeod gage at 250"C for at least 30 min at a pressure below 10 Pa (0.075 mm Hg). Calibrate the gage according to the instructions in AI.5 of Test Method D 1160. Protect the gage from exposure to atmospheric air. A6.6.2.6 Connect the gage and insert a dry ice trap between the manifold and the vacuum pump. After steady conditions have been maintained for at least 3 min, readings are made of all gages and compared with the calibrated McLeod gage. The gages shall agree to within + 1 % for routine use.

~

D 2892

dOIN'rS

35 - 40 tr~ O.D.

"~

(INOICATINGASCARITE) ,RITROGER m FIG. A6.3

Calibration of Vacuum Gages

477

i ~ D 2892

A7. T E S T M E T H O D FOR VERIFICATION OF REFLUX DIVIDING VALVES A7.7.4 A precise 5 min intervals, simultaneously replace those beakers with another pair of tared beakers. After three sets of tared beakers have been collected, return the untared beakers and shut off the flow of liquid. A7.7.5 Weigh each of the tared beakers and obtain the mass of liquid in each to the nearest gram. A7.7.6 Calculate the ratio of the mass of test liquid recovered in the beaker at the bottom of the column to that at the top of the column in each of the three 5-min tests. A7.7.7 If the ratios so obtained are not consistent to within +5 %, repeat A7.7.1 through A7.7.6. A7.7.8 Repeat the sequence A7.7.1 through A7.7.7 at flow rates equal to about 30, 60, and 90 % of the maximum boilup rates for the column under test. A7.7.9 Repeat sequence A7.7.1 through A7.7.7 for a valve operation in which the closed portion of the cycle is equal to two times the open period (2:1 ratio). A7.7.10 When the actual reflux ratio differs by more than 10 % from the desired ratio, the valve is not acceptable and must be corrected. Fig. A7.1 illustrates graphically the test results of a typical valve of acceptable performance.

A7.1 Scope A7.1.1 This test method is for determining whether a liquid reflux dividing valve produces the prescribed reflux ratio• A7.2 Summary of Test Method A7.2.1 A hydrocarbon distillate of medium density is introduced to the reflux dividing valve while operating in the normal way. The reflux ratio is determined by the ratio of the two streams so obtained. The test is conducted over a range of rates normally encountered in use to ensure that performance is acceptable at all levels. A7.3 Significance and Use A7.3.1 This test method is intended to ensure that the valve in operation actually divides the reflux in the desired ratio. A7.4 Apparatus A7.4.1 The apparatus consists of the column and reflux divider with its controller and the condenser if necessary for convenient entry of liquid to the divider. A7.4.2 A means must be provided for introducing the test liquid at steady rates over a range that includes 10 to 90 % of the maximum capacity of the column under test. This apparatus can be a pumping system, but a simple gravity flow system can be used if its reservoir is of a capacity that will ensure relatively uniform rates for each test. A supply of 400 m L beakers tared to the nearest gram and a stopwatch are also required.

A7.8 Precision and Bias A7.8.1 No statement is made concerning either the precision or bias of Annex A7 for checking the location of the temperature sensor because the result is used to determine whether there is conformance to the criteria stated in A7.7.10.

A7.5 Reagents and Materials A7.5. l The test liquid can be any hydrocarbon fraction in the kerosine to diesel oil range (150 to 300"C). A7.6 Preparation of Apparatus A7.6.1 Assemble the column in the normal way with the valve in place. Attach the condenser in its normal position if this will facilitate the introduction of the test liquid to the divider. Connect the control device to the liquid dividing valve. A7.6.2 Set an untared beaker of suitable size under the bottom of the column and another under the takeoff point. A7.6.3 Mount the liquid flow system so that the necessary range of flow rates can be provided.

]0

20

IS

.=.

%2.

-

".,

.

_~_~

......

, -+~--, ~.0

5

A7.7 Procedure A7.7. l Start the valve and set the control device in such a way that the valve is open for not less than 4 s and not more than 6 s, and closed for a period that is five times as long (5:1 ratio). A7.7.2 Commence introduction of the test liquid to the valve at a rate equal to about 10 % of the maximum boilup rate for the column under test. A7.7.3 After 2 min have elapsed, simultaneously replace the beakers under the column and under the takeoff point with tared beakers.

3~

5

FIG. A7.1

I0 IS ACtual ~gf1~ut Rl~io

30

SO

Graphical Illustration of Actual Reflux Ratio

Typical Reflux Divider

478

20

of a

tt~') D 2892 A8. T E S T M E T H O D FOR DEHYDRATION OF A S A M P L E OF WET CRUDE OIL stream of nitrogen (8 cm3/s) through the capillary. Vent the condenser through two traps in series maintained at the temperature of dry ice. Circulate coolant at a temperature of -20"C in the condensers. A8.6.3 Apply heat to the flask, regulating it to attain a moderate reflux rate as specified in 9.2.4 to 9.2.8 for debutanization. Remove distillate slowly at total takeoff (reflux ratio = 0) until a vapor temperature of 130"C is reached. Collect the fraction distilling below 65"C in a receiver cooled to -20"C or lower. A8.6.4 Shut off the reflux valve and the heating system. Cool the flask and contents to ambient temperature. Maintain the traps at the temperature of dry ice. Weigh the distillate fractions obtained. A8.6.5 To separate the water from each distillate fraction, cool to - 5 " C and decant the hydrocarbon liquid. Weigh the water. A8.6.6 Remove the condenser and rinse it with alcohol or acetone to remove adhering drops of water. Dry with air and replace it. A8.6.7 Recombine the cooled decanted fractions with the distillation residue observing the usual precautions against losses. Do not recombine the trap fraction. A8.6.8 Record the quantity of dry oil recovered. If reblending of the dried fractions was done in the original flask, this flask can be used for subsequent distillation.

A8.1 Scope A8.1.1 This test method is for dehydrating a sample of wet crude oil (>0. 1% water) prior to fractional distillation. A8.2 Summary of Test Method A8.2.1 A sufficient quantity of the sample is distilled in a low efficiency column under atmospheric pressure at zero reflux ratio (total takeoff) to 130"C, the water decanted, and dry components recombined.

A8.3 Significance and Use A8.3.1 Dehydration is important in order to achieve accurate yields in the light naphtha region. A8.4 Apparatus A8.4.1 The dehydration of a sample of wet crude oil requires apparatus such as that shown in Fig. l composed of: A8.4. I. l Distillation flask, with two side arms. In place of the differential pressure manometer in the second sidearm, a capillary is fitted for the passage of nitrogen into the liquid. When a sample is suspected of containing emulsified water or significant amounts of clay or sediment, or both, additional risk to glass apparatus is involved. In this case remove gross water and sediment and use a metal flask for dewatering. A8.4.1.2 Distillation column shall be of the type described in 6.1.3. A8.4.1.3 The rest of the apparatus is identical to that described in 6. I.

A8.7 Calculation A8.7.1 Calculate the mass-percent of water using Eq A8.1. W = 100(A/B) (A8.1) where: A = mass of water recovered, g, B --- mass of charge, g, W = Mass-percent of water, and 100 = percentage constant.

A8.5 Preparation of Apparatus A8.5.1 Clean the distillation column and all the glassware before starting the test. A8.6 Procedure A8.6.1 Cool the charge to a temperature not lower than 0*C. Decant any bulk water which may be present. Weigh by difference to the nearest g, into a chilled distillation flask containing some pieces of glass or porcelain, a given volume of wet crude oil. A8.6.2 Attach the flask to the column and pass a slow

A8.8 Precision and Bias A8.8.1 No statement is made concerning either the precision or bias of Annex A8 for mass-percent water because the test method is used primarily for sample preparation for Test Method D 2892.

A9. PRACTICE FOR CONVERSION OF OBSERVED VAPOR T E M P E R A T U R E S T O A T M O S P H E R I C E Q U I V A L E N T T E M P E R A T U R E (AET) A9.1 Scope

A9.2 Significance and Use

A9.1.1 This practice is for the conversion of actual distillation temperatures at ambient and lower pressures to atmospheric equivalent temperature (AET) corresponding to 101.3 kPa (760 mm Hg) by means of equations derived by Maxwell and Bonnell. s'9

A9.2.1 Tables 3, 4, and 5 are based upon the same equations and may be used for pressures of 13.3 kPa (100 mm Hg), 1.33 kPa (10 mm Hg), and 0.266 kPa (2 mm Hg) respectively. Fig. 5 is provided only as a guide in estimating the cut points during distillation. Final data on atmospheric

8 Maxwell and Bonnell, Industrial Engineering Chemistry, Vol 49, 1957, p. 1187.

9 These equations are convenient versions of the equations published in Section 5A 1.13 of the API Technical Data Book.

479

(@) D 2892 650 -

-

0.65

AET =

600 550

748.1A 1 - 273 T + 273 + 0.3861A - 0.00051606

where: AET = atmospheric equivalent temperature, °C, T = observed vapor temperature, "C, 5.143324 - 0.972546 log P A = 2579.329 - 95.76 log P P = pressure, between 0.27 and 101.3 kPa, or

500 -070

450 400 0.75 350 ?

-

u')

0.80

3 "d

tO

t"lO

-

0.85

>= (D rr

0.90

a~ U ~ 11.

A=

o

0.

o

.10

250

°

c

200

~

(1)

"8 g

:: 15o

K=

(A9.3)

~/1.8 (B + 273) D

(A9.4)

where: B = mean average boiling point, *C, and D = density at 15"C. By custom, either the mid vapor temperature of the fraction or the mid-point of a gas chromatographic distillation of the fraction can be used for the mean average boiling point. In either case the method must be specified. A9.3.3.1 An estimate of the K-factor can be made using Fig. A9.1. A9.3.4 Calculate the correction to be applied to the AET using Eq. A9.5:

095 100 1.00

50 1 05

FIG. A9.1

5.994296 - 0.972546 log P 2663.129 - 95.76 log P

(A9.2)

P = pressure, between 2 and 760 mm Hg. A9.3.2 The equations are correct only for fractions having a Watson K-factor of 12.0 _ 0.2 and boiling between 38 and 37 I*C. The K-factor shall be assumed to be 12 and any effect of K-factor ignored unless there is mutual agreement to the contrary. A9.3.3 If correction is required, calculate the K-factor using Eq A9.4:

aoo

g

!

~°0' E

(A9.1)

Watson Characterization Factor of Petroleum Fractions

equivalent temperatures are to be obtained either from the tables or by computation.

t = - 1.4[K - 12][log(Pa/Po)] (A9.5) where: t = correction, *C, Pa = atmospheric pressure, kPa (ram Hg), and Po = observed pressure, kPa (mm Hg). A9.3.4.1 An estimate of the correction can be made using Fig. A9.2.

A9.3 Calculation A9.3.1 Convert observed vapor temperature to atmospheric equivalent temperature using Eq A9.1.

480

~t~'~ D 2 8 9 2 0.001

0.0001

0.01

0.1

1

10

1

100

+25

I I

+20

m

~Oh-

.~

+15

'--

+10

o c 0

•o

I

100

I I I

+25

Boiling point correction for characterization factor (K)

+2o

Procedure: Add correction read from this chart to normal boiling point (AET)

+15

"~

l

0

E

10

~

.5

-----..~

l

l

l

+10

l

.

~.... 1.~

~"-

-X

~%

+5

12.0

0

.

~-~"

~ ' ~

"o "o

-5

,.-=---.,--.. mmmm n ~

o

f

v

j

c

o

-10 vl

o U

J

/

I

f

I

~ r

-15

f

/

J

f

1"~

I

-20

-15

f

J

f

J

f

-20

f

f f

-25

"~ 0.0001

0.001

0.01

2

5

0.1

2

5

2

1

Observed FIG. A9.2

5

10

2

S

100

2

S Pa

vapor pressure

1

2

I kPa I

5

10

2

5

-25 100

--~

Boiling Point Corrections for K-Factor

A10. PRACTICE FOR PERFORMANCE CHECK AIO.1 Scope A10.1.1 The determination of efficiency can be made at any cut point where samples of two or more adjacent fractions can be analyzed by gas chromatography. Either fresh or stored samples can be analyzed as long as they have been protected from loss by evaporation. The samples must be wide enough that the overlap by GC analysis does not extend beyond the middle of the fraction. Uniform 100*C wide fractions are recommended. The minimum boiling range is 50"C.

AI0.2. Referenced Documents A 10.2.1 ASTM Standards: D2887 Test Method for Boiling Range Distribution of Petroleum Fractions by Gas Chromatography 4 D3710 Test Method for Boiling Range Distribution of Gasoline and Gasoline Fractions by Gas Chromatography 4

A10.3 Significance and Use

achieved under a variety of conditions because efficiency has no measurable effect on yields except at the beginning and end of a distillation. However, fractions produced at high efficiency will have a narrower boiling range and hence some different properties than the same fraction made at low efficiency. Similarly, concentrations of aromatics, for instance, will be sharpened by high efficiency but are largely unnoticed at lower levels. In order to arrive at a standard level of efficiency, the following overall check is recommended in place of Annexes A1 through A5 inclusive and Annex A7. Calibrations prescribed in Annex A6 should be done routinely. If the results of this test (Annex A 10) are unacceptable, then the foregoing annexes should be considered to determine the cause. A 10.3.2 A precise method for the calculation of efficiency at a cut point has been developed ~° and must be used in cases of dispute. A graphical solution by this method is included in Fig. AI0.1.

l o Butler and Pasternak, 42, 1964, p. 47.

AI0.3.1 Good agreement in yield of fractions can be

481

The Canadian Journal of Chemical Engineering, Vol

D 2892

~)

k--" L,~

(.;

C~

k" L~ T

k,-

,¢

•1 0

#O

4¢

fo

4,.0

70

CROSS CONTAMINATIONON CRUDE, mass-% FIG. A10.1

Efficiency Calculation

A10.4 Summary of Practice

Agreement must be as close as practical using steps of 0.5°C and interpolating where necessary. A 10.6. I. l The example uses excerpts from the following gas chromatographic analysis.

A10.4.1 The cross contamination between the adjacent fractions is calculated as the temperature at which the overlaps are equal on the basis of mass-percent of the charge. This is an empirical method and is done by trial and error to an accuracy of 0.5°C.

A10.5 Procedure AI0.5.1 Obtain samples of at least two contiguous fractions from each level of pressure and analyze them according to Test Methods D 2887 or D 3710, whichever is appropriate. Ensure that temperatures are printed in °C for every 1% from 0 to 100 %. Obtain the yield of each fraction in mass-percent of the crude oil charged to the distillation.

A10.6 Calculation A10.6.1 Select a temperature at the end of Fraction 1 which when converted to yield in mass-percent of the charge will approximate the yield in mass percent of the charge of the front end of the next cut at the same temperature.

482

% by D 2887 Fraction I

BP'C (C4-93"C)

85 86 87 88 89 90

91 92 93 93 95 96

Fraction 2

(93-149"C)

10 11 12 13 14 15

91 92 93 94 94 95

85 86 87 88 89 90

148 149 150 151 152 152

6.5 Weight % on Crude Cut point 93"C 100 - 87.5 = 12.5 % o n c u t 12.5 × 0.065 = 0.813 % on crude

6.8 Weight % on Crude Cut point 93 12.0 × 0.068 = 0.816 on crude + 0.813 C = 1.629 %

Cut point 151.5"C 1 0 0 - 88.5 = 11.5 % o n 11.5 × 0.068 = 0.781%

cut on crude

D 2892 Efficiency Standard 15/5 for Crudes from 25-40 °

TABLE A10.1

API (tentative) Cut Point °C

Standard Efficiency Theoretical Plates

50 100 150 200 250 300 350

5.4 5.5 5.6 6.2 6.8 7.7 9.0

Fraction 3

(149-204"C)

5 6 7 8 9 I0

147 149

+ + + + + + +

1.0 0.9 0.8 0.9 0.9 1.1 1.5

-

0.6 0.8 0.7 0.8 0.6 0.9 1.2

9.4 Weight % on Crude z

150 151 ~i 152 J 153

Cut point 151.5"C 8.5 x 0.094 = 0.799 % on crude + 0.781 C = 1.580 %

~P

AI0.6.1.2 In the above example, the heavy end contamination (tail) of Fraction 1 is 0.813 mass-% at 93°C. Similarly, the light end contamination (leader) of Fraction 2 is 0.816 mass-% and the cut point is 93°C. AI0.6.1.3 Performing the same calculation on cuts 2 and 3, the sum of the contamination is 1.580 mass-% and the cut point 151.5°C. A 10.6.2 Calculate the efficiency at each cut point.

CROSS CONTAHINATION OH CRUDE, mass-g FIG. A10.2

T + 273 n =

48 S

Efficiency Nomograph

(AI0.I)

purposes. A 10.6.3 The following table defines the acceptable limits for efficiency in the performance of a standard distillation. A10.6.4 These limits will be reviewed from time to time and may be adjusted. Fig. AI0.3 is a graph of the limits shown.

where: n = efficiency in theoretical plates, T = cut point, °C, and S = sum of contamination. A10.6.2.1 A graphical solution to equation AI0.1 is shown in Fig. A I0.2 and is sufficiently accurate for practical

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reepproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration st a meeting of the responsible technical committee, which you may attend, ff you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 100 Barr Harbor Drive, West Conshohockan, PA 19428.

483

(~l~ Designation: D 3054 - 95 Standard Test Methods for Analysis of Cyclohexane by Gas Chromatography 1 This standard is issued under the fixed designation D 3054; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (~) indicates an editorial change since the last revision or reapproval.

procedure is used when the impurities are at 0.00010 to 0.1000 wt% levels. A known amount of internal standard is added to the sample. A portion of the sample is injected into the chromatograph and the levels of impurities are calculated relative to the amount of internal standard added. The amount of all impurities, including benzene, is subtracted from 100.00 to establish the purity of the cyclohexane samples. 3.2 Test Method B: Straight Normalization Procedure--A portion of the sample is injected into the chromatograph using a microlitre syringe at the specified conditions of the test method. The area of all the peaks and main component are electronically integrated. These areas are normalized to 100.00 %.

1. Scope 1.1 These test methods cover the determination of the hydrocarbon impurities typically found in cyclohexane and the purity of cyclohexane by difference by gas chromatography. The absolute purity of cyclohexane cannot be determined, since trace quantities of unknowns may be present. Typical impurities in high purity cyclohexane are listed in Table 1. 1.2 These test methods are applicable to impurity concentrations in the range of 0.0001 to 0.1000 wt% and for cyclohexane purities of 98 % or higher when using the internal standard procedure. 1.3 The following applies to all specified limits in this test method: for purposes of determining conformance with this test method, an observed value or a calculated value shall be rounded off to the nearest unit in the last right-hand digit used in expressing the specification limit, in accordance with the rounding-off method of Practice E 29. 1.4 This standard does not purport to address all of the ~'afi,ty concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements, see Note 2 and Section 7.

4. Significance and Use 4.1 These test methods are suitable for establishing contract specifications on cyclohexane and for use in internal quality control where cyclohexane is either produced or used in a manufacturing process. They may also be used in development or research work. TABLE 1

Impurities Known or Suggested to be Present in Commercial Cyclohexane

2. Referenced Documents 2.1 A S T M Standards: D 3437 Practice for Sampling and Handling Liquid Cyclic Products 2 E 29 Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications3 E 260 Practice for Packed Column Gas Chromatography 3 E 691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method 3 E 1510 Practice for Installing Fused Silica Open Tubular Capillary Columns in Gas Chromatographs 3 2.2 Other Document: OSHA Regulations, 29 CFR, Paragraphs 1910.1000 and 1910.12004 3. Summary of Test Methods 3.1 Test Method A: Internal Standard Procedure--This i These test methods are under the jurisdiction of ASTM Committee !)-16 on Aromatic Hydrocarbons and Related Chemicals and are the direct responsibility of Subcommittee DI6.0A on Benzene, Toluene, Xylenes, Cyclohexane, and Their Derivatives. Current edition approved Sept. 15, 1995. Published November 1995. Originally published as D 3054 - 93. Last previous edition D 3054 - 93 ~. 2 Annual Book of ASTM Standards, Vol 06.04. 3 Annual Book of ASTM Standards, Vol 14.02. 4 Available from Superintendent of Documents, U.S. Government Printing Office, Washington, DC 20004.

C4 (1) n-butane (2) isobutane C6 (3) n-pontane (4) isopontane (5) cyclopentane Ce (6) n-hexaneA (7) 2-methylpentane (8) 3-methylpentane (9) methylcyclopentane 'l (10) benzeneA (11) 2,2-dimethylbutane (12) 2,3-dimethylbutane C7 (13) 3,3-dimethylpentane (14) 2,3-dlmethylpentane (15) 1,1-dimethylcydopentane (16) 1,t3.dimethylcyclopentane (17) 1,t2-dimethylcyclopentane (18) 1 ,c2-dimetbylcyclopontane (19) 2,2-dlmethyipentane (20) 2,4-dimethyipentene (21) 1,c3-dimethylcyclopentane (22) ethylcyclopentane (23) methylcyclohexaneA (24) 3-ethylpentane (25) 3-methylhexane (26) 2-methylhexane (27) n-heptane A These components were used to prepare the standards used in the round robin progrsm.

484

~1~ D 3054 TABLE 2

umn is a methyl silicone-fused silica capillary column. Any other column used must be capable of resolving all significant impurities from cyclohexane. The internal standard peak must be individually resolved without interference from cyclohexane or any other impurities. A typical chromategram with the identified impurities is found in Fig. 1. 5.2.1 Cross.Linked Methyl Silicone Fused Silica Capillary Column, 60 m by 0.50 Ixm film thickness by 0.32 mm diameter• 5.3 Integrator or Data Handling System--Electronic or equivalent equipment for obtaining peak areas. This device must integrate areas at a rate of 15 readings per second so that very narrow peaks resulting from fused silica capillary columns can be accurately measured. 5.4 Microsyringes, capacities 1.0 or I0 I~L, and 50 pL. 5.5 Volumetric Flasks, 100-mL capacity.

Typical Instrument Conditions for Cyclohexane Analysis (See Chromatogram Fig. 1)

Instrument: Range Attenuation inlet, *C Detector, *C Sample size, I~L Column: Carrier gas Linear velocity, cm/sec Split ratio Tubing Stationary phase Solid support Film thickness, p.m Length, m Inside diameter, mm Temperature Program: Initial, *C Time, rain Rate No. 1, *C/min Intermediate, *C Time, mln Rate No. 2, *C/rain Final, *C Time, mln Internal Standard: 2,2.Dlmethylbutane

3 1 200 275 1.2 helium 20.0 45:1 fused silica methyl silicone cross-linked 0.50 60 0.32 32 6 5 52 5 20 230 9

6. Reagents and Materials 6.1 2,2-Dimethylbutane, 99.0 % minimum purity (internal standard). 6.2 Helium. 6.3 Hydrogen and Air, for FID detector. 7. Hazards 7.1 Consult current OSHA regulations, suppliers' Material Safety Data Sheets (MSDS), and local regulations for all materials used in this test method.

NOTE l--In case of dispute, the internal standard procedure will be the correct procedure to use.

5. Apparatus 5.1 Gas Chromatograph (GC) (for a Fused Silica Column)--A multi-ramp temperature, programmable GC built for capillary column chromatography. It must have a flame ionization detector and a split injection system that will not discriminate over the boiling range of the samples analyzed. 5.1.1 Gas Chromatograph--Any chromatograph having a flame ionization detector that can be operated at the conditions given in Table 2. The system should have sufficient sensitivity to obtain a minimum peak height response for a 0.0001 wt% impurity twice the height of the signal background noise. 5.2 Chromatographic Column--The recommended col-

8. Sampling 8.1 Take samples in accordance with Practice D 3437. 9. Procedures 9.1 Test Method A: 9.1.1 Internal Standard Procedure--Install the chromatographic column and establish stable instrument operation at the proper operating conditions shown in Table 2. The selected column and conditions must satisfy the resolution requirements as stated in 5.2. Make reference to instructions provided by the manufacturer of the chromatograph, and to Practices E 260 and E 1510.

1 ;

| ~°nn

i

I! m 0.00 RT tn L t n u t u

I1.•

I

!

7.N

W.W

•

ULN

!

~S.(IO

ASTN IP8054 ROUNDROB~ SkqaLE: SX 110-4437 ~¢JECTED AT f3:Oe:OSONNOV SO, t880 Neth: I)3054 Flare. R~.i04 Pro¢ P~.i04 FIG. 1

Sample 110-4437

485

!

~.m

n.W

~) O 3054 TABLE 3

9.1.2 Place 50 to 60 mL of the cyclohexane sample to be analyzed into a 100-mL volumetric flask. Accurately add, using a micropipet or microsyringe, 25 ~tL of the internal standard to the flask and then fill to the calibration mark with additional sample. Based on using 2,2-dimethylbutane as the internal standard with a density of 0.649 g/mL and cyclohexane with a density of 0.780 g/mL, the concentration of the internal standard will be 0.021 wt%. Similar calculations must be made for any alternative internal standard that may be used. Mix the above, blend thoroughly, and analyze using the chromatographic conditions stated in Table 2. 9.2 Test Method B: 9.2.1 Straight Normalization ProcedureDProceed as in 9.1.1. Then, inject a proper specimen size directly into the gas chromatograph. Integrate all peaks, impurities, and cyclohexane. NOTE 2: Caution--A smaller specimen size might be required so as

Intermediate Precision (Formerly Called Repeatability) and Reproducibility A Intemel Standard Method

Component

AverageExpected Reported Intermediate ReproducConcentration Concentration Precision ibility wt% wt%

Purity

not to exceed the dynamic range of the instrument used.

99.9755 99.7866

99.8753 99.7820

0.0005 0.0034

0.0012 0.0160

n-Hexane

0,0050 0.0207

0.0050 0.0190

0.0001 0.0004

0,0003 0.0012

n-Heptane

0.0049 0.0208

0.0050 0.0212

0.0002 0.0004

0.0004 0.0013

Methyl cyclopentane

0.0047 0.0208

0,0049 0.0221

0.0001 0.0004

0,0004 0.0017

Benzene

0.0010 0.0507

0.0009 0.0532

0.0001 0.0014

0.0003 0.0086

Methylcyclohexene

0.0089 0.1004

0.0089 0,1025

0.0004 0.0031

0.0010 0.0134

,* Outliars removed from data.

10. Calculation

10.1 Calculation for Internal Standard Procedure: 10.1.1 Determine the response factor for each impurity relative to the internal standard by measuring the area under each peak and calculate as follows:

(A,XC,)

R~ = ~ (c,.) (A,)

A~ -- integrated area for impurity peak "i", and A2 = total integrated areas of all peaks. 12. Report 12. l Report the following information: 12.l.1 The cyclohexane purity of the sample to the nearest 0.01 wt%. 12.1.2 The amount of each impurity in the sample to the nearest 0.0001 wt% for the Internal Standard Procedure and to the nearest 0.0010 wt% for the Straight Normalization Procedure.

(1)

where: R; = response factor for impurity, i, relative to the internal standard, Ai = peak area of impurity, i, A~.= peak area of internal standard, Cs = concentration of the internal standard, and C; = concentration of impurity, i, as calculated in 9.1.2. 10.1.1.1 Calculate the impurities as follows: C~ =

(A,)(R,)(C,) (A,)

13. Precision and Bias s

13.1 PrecisionmThe following criteria should be used to judge the acceptability (95 % probability level) of results obtained by this test procedure. The criteria were derived from an interlaboratory study among seven participating laboratories. The data were determined on two days using different operators and using two samples. The samples were gravimetrically prepared from recrystallized cyclohexane and the individual hydrocarbon impurities to the concentrations listed in Tables 3 and 4. The results of the interlaboratory study were calculated and analyzed using Practice E 69 I. 13.l.l Results in the same laboratory should not be considered suspect unless they differ by more than the amount shown in Table 3 and Table 4. On the basis of test error alone, the difference between two test results obtained in the same laboratory on the same material will be expected to exceed this value only 5 % of the time. 13.1.2 Results obtained by each of two laboratories should not be considered suspect unless they differ by more than the amount shown in Table 3 and Table 4. On the basis of test error alone, the difference between two test results obtained in different laboratories on the same material will be expected to exceed this value only 5 % of the time. 13.2 Bias--Although the interlaboratory test utilized a sample prepared gravimetrically from chemicals obtained at

(2)

and: 10.1.2 Calculate the total concentration of impurities as follows:

C,=ZC,., where: C, = total concentration of all impurities, weight %. 10.1.3 Cyclohexane Purity by Difference (Weight PercenO: Cyclohexane, % = 100.00 - Ct (3) NOTE 4--First, convert total impurities to weight percent and then subtract from 100. 10.2 Calculation for Straight Normalization Procedure: NOTE 5--Detector response factorshave been establishedto be equal to unity; therefore, area percent is equivalent to weight percent. 10.2.1 Area Percent Cyclohexane: Cyclohexane, % = (A dA2) x 100 (4) where: A I = integrated area of cyclohexane, and A2 = total integrated areas of all peaks. 10.2.2 Area Percent Impurities:

impurity-i,

% -- (AI/A2) X 100

s Supporting data are available from ASTM Headquarters. Request RR: DI6-1016.

(5)

where: 486

(!~ D 3054 TABLE 4

the highest purity available, these samples have not been approved as an acceptable reference material and consequently bias has not been determined. 13.2.1 As an aid for the users in determining the possibility of bias, the calculated concentration of each impurity in the two round robin samples is listed in Tables 3 and 4 as the "expected concentration." The average value for each impurity as reported from the six participating laboratories is listed as "average concentration reported."

Intermediate Precision (Formerly Called Repeatability) and Reproducibility A Straight Normalization Method Expected AverageConcentration Reported Intermediate ReproducConcentration Precision ibility wt % wt~

Component

Purity

99.9755 99.7877

99.9766 99.7877

0.0016 0.0118

0.0063 0.0264

n-Hexane

0.0050 0.0207

0.0048 0.0190

0.0003 0.0023

0.0011 0,0039

n-Heptane

0.0049 0,0208

0.0048 0.0206

0.0002 0.0016

0.0007 0.0020

Methylcyclopentane

0.0047 0.0208

0.0045 0.0209

0.0003 0.0022

0.0013 0.0033

Benzene

0.0010 0.0507

0.0006 0.0508

0.0005 0.0023

0.0018 0.0089

Methylcyclohexane

0,0089 0.1004

0.0087 0.1010

0.0003 0.0033

0.0013 0.0084

14. Keywords

14.1 cyclohexane; gas chromatography; impurities

A Outliers removed from data.

The American Society for Testing and Materials takes no position respecting the vafidity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reepproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at e meeting of the responsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103.

487

(~~I~1~ Designation:D 3120 - 96

An American National Standard

Standard Test Method for Trace Quantities of Sulfur in Light Liquid Petroleum Hydrocarbons by Oxidative Microcoulometry 1 This standard is issued under the fixed designation D 3120; the number immediately following the designation indicates the year of original adoption or, in the ease of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (~) indicates an editorial change since the last revision or reapproval.

1. Scope 1.1 This test method covers the determination of sulfur in the range from 3.0 to 100 ppm (~tg/g) in light liquid hydrocarbons boiling in the range from 26 to 274°C (80 to 525"F). 1.2 This test method may be extended to liquid materials with higher sulfur concentrations by appropriate dilution. 1.3 The preferred units are micrograms per grams. Values stated in SI units are to be regarded as the standard. Values in inch-pound units are for information only. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements, see 6.3, 6.4, 6.8, and 6.10.

the process. Higher concentrations of sulfur in products analyzed by this test method after appropriate dilution are often detrimental to the use of the product. 4. Interferences 4.1 This test method is applicable in the presence of total halide concentrations of up to 10 times the sulfur level and total nitrogen concentrations of up to 1000 times the sulfur level. 4.2 This test method is not applicable in the presence of total heavy metal concentrations (for example, Ni, V, Pb, etc.) in excess of 500 ~g/g (ppm). NOTE I - - T o attain the quantitative detectability that the method is capable of, stringent techniques must be employed and all possible s o u r c e s o f sulfur contamination must be eliminated.

5. Apparatus 2 5.1 Pyrolysis Furnace--The sample should be pyrolyzed in an electric furnace having at least two separate and independently controlled temperature zones, the first being an inlet section that can maintain a temperature sufficient to volatilize all the organic sample. The second zone shall be a pyrolysis section that can maintain a temperature sufficient to pyrolyze the organic matrix and oxidize all the organically bound sulfur. A third outlet temperature zone is optional. 5.1.1 Pyrolysis furnace temperature zones for light liquid petroleum hydrocarbons should be variable as follows:

2. Summary of Test Method 2.1 A liquid sample is injected into a combustion tube maintained at about 800°C having a flowing stream of gas containing about 80 % oxygen and 20 % inert gas (for example, nitrogen, argon, etc.). Oxidative pyrolysis converts the sulfur to sulfur dioxide which then flows into a titration cell where it reacts with triiodide ion present in the electrolyte. The triiodide thus consumed, is coulometrically replaced and the total current required to replace it is a measure of the sulfur present in the sample injected. 2.2 The reaction occurring in the titration cell as sulfur dioxide enters is:

Inlet zone Center pyrolysis zone Outlet zone (optional)

13- + S O 2 + H 2 0 ---} SO 3 + 31- + 2H +

up to at least 700"C 800 to 1000"C up to at least 800"C

5.2 Pyrolysis Tube, fabricated from quartz and constructed in such a way that a sample, which is vaporized completely in the inlet section, is swept into the pyrolysis zone by an inert gas where it mixes with oxygen and is burned. The inlet end of the tube shall hold a septum for syringe entry of the sample and side arms for the introduction of oxygen and inert gases. The center or pyrolysis section should be of sufficient volume to ensure complete pyrolysis of the sample. 5.3 Titration Cell, containing a sensor-reference pair of electrodes to detect changes in triiodide ion concentration and a generator anode-cathode pair of electrodes to maintain constant triiodide ion concentration and an inlet for a

The triiodide ion consumed in the above reaction is generated coulometrically thus: 3I- --, 13- + 2e2.3 These microequivalents of triiodide (iodine) are equal to the number of microequivalents of titratable sample ion entering the titration cell. 3. Significance and Use 3.1 This test method is used to determine trace quantities of sulfur in reformer charge stocks and similar petroleum fractions where such trace concentrations of sulfur are deleterious to the performance and life of the catalyst used in

2The apparatus described in Sections 5.1 to 5.5 inclusive, is similar in specifications to equipment available from Dohrmann Div. of Rosemount, 3240 Scott Blvd., Santa Clara, CA 95050. For further detailed discussions, in equipment, see: Preprints--Division of Petroleum Chemistry, American Chemical Society, Vol I, No. 3, Sept. 7-12, 1969, p. B232 "Determination of Sulfur, Nitrogen, and Chlorine in Petroleum by Microcoulometry," by Harry V. Drusbel.

This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.03 on Elemental Analysis. Current edition approved Apr. 10, 1996. Published June 1996. Originally published as D 3120 - 72 T. Last previous edition D 3120 - 92.

488

o a12o NOTE 6: Warning--Compressed gas under high pressure. Gas reduces oxygen available for breathing.

gaseous sample from the pyrolysis tube. The sensor electrode shall be platinum foil and reference electrode platinum wire in saturated triiodide half-cell. The generator anode and cathode half-cell shall also be platinum. The titration cell shall require mixing, which can be accomplished through the use of a magnetic stirring bar, stream of inert gas, or other suitable means.

6.5 Cell Electrolyte Solution--Dissolve 0.5 g of potassium iodide (KI) and 0.6 g of sodium azide (NAN3) in approximately 500 mL of high-purity water, add 5 mL of acetic acid (CH3COOH) and dilute to 1000 mL. NOTE 7--Bulk quantities of the electrolyte should be stored in a dark bottle or in a dark place and be prepared fresh at least every 3 months.

NOTE 2: Caution--Excessive speed will decouple the stirring bar, causing it to rise in the cell and damage the electrodes. The creation of a slight vortex is adequate.

5.4 Microcoulometer, having variable attenuation, gain control, and capable of measuring the potential of the sensing-reference electrode pair, and comparing this potential with a bias potential, amplifying the potential difference, and applying the amplified difference to the working-auxiliary electrode pair so as to generate a titrant. Also the microcoulometer output voltage signal shall be proportional to the generating current. 5.5 Recorder, having a sensitivity of at least 0.1 mV/in. with chart speeds of 1/2 to 1 in./min. Use of a suitable electronic or mechanical integrator is recommended but optional. 5.6 Sampling SyringemA microlitre syringe of 10-~tL capacity capable of accurately delivering 1 to I0 ktL of sample into the pyrolysis tube. 3-in. by 24-gage needles are recommended to reach the inlet zone of the pyrolysis furnace. NOTE 3--Since care must be taken not to overload the pyrolyzing capacity of the tube by too fast a sample injection rate, means should be

6.9 n-Butyl Sulfide (CH3CH2CH2CH2)2S. 6. l0 Oxygen, high purity grade (HP), 4 used as the reactant gas. NOTE 10: Warning--Oxygen vigorously accelerates combustion.

6. l 1 Potassium Iodide (KI), fine granular. 6.12 Sodium Azide (NaN3), fine granular. NOTE l l: Warning--Toxic, causes eye and skin irritation; explosive.

6.13 Sulfur, Standard Solution (approximately 30 ~tg/g (ppm))--Pipet l0 mL of sulfur stock solution (reagent 6.14) into a 100-mL volumetric flask and dilute to volume with isooctane.

provided for controlling the sample addition rate (0.1 to 0.2 laL/s).

6. Reagents and Materials 6. l Purity of Reagents--Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, where such specifications are available) Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination. 6.2 Purity of Water--The water used in preparing the cell electrolyte should be demineralized or distilled or both. Water of high purity is essential.

NOTE 12--The analyst may choose other sulfur compounds for standards appropriate to sample boiling range and sulfur type which cover the concentration range of sulfur expected.

6.14 Sulfur, Standard Stock Solution (approximately 300 Ixg/g (ppm))mWeigh accurately 0.5000 g of n-butyl sulfide into a tared 500-mL volumetric flask. Dilute to the mark with isooctane and reweigh. S, ppm (p.g/g) = g of n-butyl sulfide x 0.2187 x l06 g of (n-butyl sulfide + solvent)

7. Preparation of Apparatus 7.1 Carefully insert the quartz pyrolysis tube in the pyrolysis furnace and connect the reactant and carrier gas lines. 7.2 Add the electrolyte solution to the titration cell and flush several times. Maintain an electrolyte level of I/8 to I/4 in. (3.2 to 6.4 mm) above the platinum electrodes. 7.3 Place the heating tape on the inlet of the titration cell. 7.4 Position the platinum foil electrodes (mounted on the moveable cell head) so that the gas inlet flow is parallel to the electrodes with the generator anode adjacent to the generator cathode. Assemble and connect the coulometer and recorder (integrator optional) as designed or in accordance with the manufacturer's instructions. Figure X I.2 illustrates the typ-

NOXE4--Distilled water obtained from an all borosilicate glass still, fed from a demineralizer, has proven very satisfactory. 6.3 Acetic Acid (rel dens (CH3COOH).

6.6 Gas Regulators--Two-stage gas regulators must be used on the reactant and carrier gas. 6.7 Iodine (I), 20 mesh or less, for saturated reference electrode. 6.8 Isooctane 5 (2,2,4-trimethylpentane). NOTE 8: Warning--Extremely flammable. Harmful if inhaled. Vapors may cause flash fire. NOTE 9--The most reliable solvent is a sulfur-freeform of the sample type to be analyzed. Alternatively,use a high-purity form ofcyclohexane [boiling point 80"C (176"F)], isooctane (2,2,4-trimethyl pentane) [boiling point, 99.3"C (211*F)], or hexadecane [boiling point, 287.5"C (549.5"F)].

1.05)--Glacial acetic acid

NOTE 5: Warning--Poison. Corrosive. Combustible. May be fatal if swallowed. Causes severe burns. Harmful if inhaled. 6.4 Argon, Helium, or Nitrogen, high purity grade (HP), 4 used as carrier gas. 3 Reagent Chemicals, American Chemical Soctety Specificattons, American Chemical Society, Washington, DC. For suggestionson the testing of reagents not listed by the American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the Umted States Pharmacopeia and National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville, MD. 4 High-purity grade gas has a minimum purity of 99.995 %.

s Pesticide test grade such as Mallinckrodt "Nano-grade'" isooctane has been found satisfactory.

489

~

D 3120

100 - -

95--

90 n

\

\ \

85--

E~

\ t~

\

80--

\

\

\

75--

\

70 m

65

..-42 ~E}.___

__.El_-

j

l

I

l

i

I

I

I

700

750

800

850

900

950

1000

Center FurnaceTemperature(°C)

Oxidative sulfur system: Thiophene in cyclohexane(10 ppm S) using 0.06~ aside electrolyte Flow rate (cc/min) Legend

®

Q

El----El ,~, FIG. 1

&

Oxygen

Argon

O2/Ar ratio

40

16o

1:4

lOO

lOO

,:,

160

,0

4:1

Percent Recovery versus Temperature (°C)

ical assembly and gas flow through a coulometric apparatus. 7.4.1 Turn the heating tape on. 7.5 Adjust the flow of the gases, the pyrolysis furnace temperature, titration cell, and the coulometer to the desired operating conditions. Typical operational conditions are given in Table I.

NOTE 13--See Fig. 1 for the variance of percent recoveries with gas ratios and temperature.

8.3 The sample size can be determined either volumetrically or by mass. The sample size should be 80 % or less of the syringe capacity. 8.3. l Volumetric measurement can be obtained by filling the syringe with about 8 ~tL or less of sample, being careful to eliminate bubbles, retracting the plunger so that the lower liquid meniscus falls on the l-~L mark, and recording the volume of liquid in the syringe. After the sample has been injected, again retract the plunger so that the lower liquid meniscus falls on the 1-1zL mark, and record the volume of liquid in the syringe. The difference between the two volume

8. Calibration and Standardization

8.1 Prepare a series of calibration standards covering the range of sulfur concentration expected. Follow instructions in 6.13, 6.14, or dilute to appropriate level with isooctane. 8.2 Adjust the operational parameters (7.5). 490

~ TABLE 1

D 3120 TABLE 2

Typical Operational Conditions

Reactant gas flow (oxygen), cma/min Carder gas flow (At, He, N) cma/min Furnace temperature; oC: Inlet zone Pyrolysis zone Outlet zone Titration cell Coulometer: Bias voltage, mV Gain

160 40

Sample Type Naphthas

700 800 800 set to produce adequate mixing

R M V D F

readings is the volume of sample injected. 8.3.2 Alternatively, the sample injection device may be weighed before and after the injection to determine the amount of sample injected. This technique provides greater precision than the volume delivery method, provided a balance with a precision of +0.00001 g is used. 8.4 Insert the syringe needle through the inlet septum up to the syringe barrel and inject the sample or standard at an even rate not to exceed 0. l to 0.2 ~tL/s. I f a microlitre syringe is used with an automatic injection adapter, the injection rate (volume/pulse) should be calibrated to deliver 0. l to 0.2 ttL/s. 8.5 Repeat the measurement of each calibration standard at least three times.

= = = ffi

Boiling=C Point ('F)Range

Sulfur Compound

26 to 204

cyOohexane sulfide

(80to 400)

Jet fuels and stove oil

160 low (approximately 200)

Satisfactory Standard Materials

177 to 274 (350 to 525)

banzyl-thlophene

coulometer range switch setting, fl, mass of sample, g (volume x density), volume of sample, ttL, density of sample, g/mL, and recovery factor, fraction of sulfur in standard that is titrated, ratio of ppm sulfur determined in standard divided by the known ppm sulfur in standard. F ffi (,4 x 1.99)/(R x M x C=d)

where: concentration of standard, ppm. 10.2 Derivation of the calculation equation will be found in XI.3. Cst d

NOTE 15--The calculation equation is valid only when the chart speed is 0.5 in./min and a 1-mV (span) recorder with a sensitivity of 0.1 mV/in, is used. NOTE 16--If a disk integrator is used, see XI.3 for calculations, derivations, and equations. NOTE 17--A more general form of the equation in 10.1 which is not dependent on the use of a particular recorder scale nor a disk integrator is as follows:

NOTE 14--Nog all of the sulfur in the sample comes through the furnace as titratable SO2. In the strongly oxidative conditions of the pyrolysistube some of the sulfur is also converted to SO3 which does not react with the titrant. Accordingly, sulfur standards of n-butyl sulfide in isooctane or sulfur standards appropriate to sample boiling range and sulfur type and sulfur concentration should be prepared to guarantee adequate standardization. Recoveries less than 75 % are to be considered suspect. Low recoveries are an indication to the operator that he should cheek his parameters, his operating techniques, and his ¢oulometric system. If the instrument is being operated properly, recoveries between 75 and 90 % are to be expected. Satisfactory standard materials6 are given in Table 2.

(A) (X) (0.166)

sulfur, ppm (ttg/g) = (R) (Y) (M) (F) where: A = area in appropriate units, X = recorder sensitivity for full-scale response (mv), 0.166 ffi (16 gS/eq) (10-3 V/mV) (106 txg/g) (96 500 coulombs/eq)

8.6 If the fraction of sulfur converted to SO2 drops below 75 % of the standard solutions, fresh standards should be prepared. If a low conversion factor persists, procedural details should be reviewed.

R = resistance, fl, Y = area equivalence for a full-scale response on the recorder per s e c o n d . . , area units per second, M = mass of sample, g, and F = recovery factor.

9. Procedure 9.1 Flush the 10-ttL syringe several times with the unknown sample. Determine the sulfur concentration in accordance with 8.2 to 8.6. 9.2 Sulfur concentration may require adjustment of sensifixity settings or sample volume or both.

11. Precision and Bias 11.1 The precision of this test method as obtained by statistical examination of interlaboratory test results is as follows: 11.1.1 Repeatability--The difference between successive test results obtained by the same operator with the same apparatus under constant operating conditions on identical test material would, in the long run, in the normal and correct operation of the test method exceed 28 % of the average value only in one case in twenty. 11.1.2 Reproducibility--The difference between two single and independent results obtained by different operators working in different laboratories on identical test material would, in the long run, in the normal and correct operation of the test method exceed 38 % of the average only in one case in twenty. 11.2 Bias--Since there is no accepted reference material suitable for determining the bias for the procedure in this test

10. Calculation 10.1 Calculate the sulfur content of the sample in parts per million, p p m ~tg/g, by mass as follows: Sulfur, ppm ttg/g ffi (.4 x 1.99)/(R x M x F) (1) Sulfur, ppm = (A X 1.99 x 10a)/(R x V x D x F) (2) where: A = area under curve, in. 2, 1.99 = derivation will be found in X1.3, 6 Wallace, L. D., "Comparison of Oxidative and Reductive Methods for the Microcoulometric Determinations of Sulfur in Hydrocarbons," Analytical Chemistry, Vol 42, March 1970, p. 393.

491

~

D 3120

method, no statement on bias is made. 7

12. Keywords 12.1 light hydrocarbons; microcoulometry; sulfur

7SupportingdataareavailablefromASTM.RequestRR:D02-I036. APPENDIX

(Nonmandatory Information) XI. DERIVATION OF COULOMETRIC CALCULATIONS USED IN SECTION 10.1 X 1.1 The configuration of the pyrolysis tube and furnace may be constructed as is desirable as long as the operating parameters are met. Figure X I. 1 is typical of apparatus currently in use. X I.2 A typical assembly and oxidative gas flow through a coulometdc apparatus for the determination of trace sulfur is shown in Fig. XI.2. X 1.3 Derivation of Equations:

X I.3.1 The derivation of the equations used in the calculation section is based on the coulometric replacement of the tdiodide (iodine) ions consumed in the microcoulometric titration cell reaction (I3- + 2e- -* 3I-. The quantity of the reactant formed (triiodide ions) between the beginning and the interruption of current at the end of the titration is directly proportional to the net charge transferred,

Q. X 1.3.2 In most applications a constant current is used so that the product of current, i, in amperes (coulombs per second), multiplied by the time, T (seconds), required to reach the end point provides a measure of the charge, Q (coulombs), necessary to generate the iodine equivalent to the reactant; that is, Q ffi it. Therefore, the number of equivalents of reactant is equal to Q/F, where F is the Faraday constant, 96 500 C per equivalent. XI.3.3 Therefore, the expression to be solved to find the mass of reactant is:

Furnace Outlet

Center

Inlet

', ,_-=: Carrlt. r (,as A rgon

FIG. X1.1

Pyrolipla Tube

Inlet

Outlet

Sample Injection Z~ne pyz:l::i s Zone

7

I

Titration Cell Potentiometric Recorder

FIG. X1.2

Flow Diagram for Coulometdc Apparatus for Trace Sulfur Determination

492

(~ D 3120 Q(C)

16 g X FC eq eq mass o f sample, g

~

C o n c e n t r a t i o n o f sulfur =

lagS=Ain.

2X

mass o f sulfur, g mass o f sample, g

0.1 m____~Vx 2 min x 60: s x -10 -3 - V x in. in. mm mV R ( a ) x 96 500___ C x ~ eq

= peak area m e a s u r e d in square inches, = millivolt span o f upscale deflection for the recorder, 2 min/in. = chart speed in minutes per inch, 60 s/rain = conversion o f t i m e in m i n u t e s to seconds, 10 -3 V / m V = conversion o f volts to millivolts, 16 g/eq = g r a m - e q u i v a l e n t o f sulfur, 10 6 lag/g = m i c r o g r a m s p e r g r a m conversion factor, R(fl) = m i c r o c o u l o m e t e r range switch setting in ohms, substituting V]R = 1 (amps) A in.Zx Q(A.s) =

10 6

lag

lag S = (A x 1.99)/(R x f )

(Xl.5)

(Xl.6)

Since p p m = lag/g: ppm S =

A x 1.99

R xfx

volume, laL

(XI.7)

x 103 ~-~ x density, m ~L

0.1 mV 2 m i n 60s 10- 3 V x x x - in. in. min mV R(a)

A x 12 x 10-3 × 16 x R x 96 500 x f

Therefore,

A x 1.99 x 103 ppm S = R x f x volume x density (X 1.3)

(XI.8)

Since mass - v o l u m e x density ppm S -- (A x 1.99)/(R x f x

96 500 C/eq F a r a d a y ' s c o n s t a n t s (electrical equivalence o f one g r a m - e q u i v a l e n t mass o f any substance) = conversion o f c o u l o m b s to ampere-seconds, and = recovery factor (ratio o f p p m S d e t e r m i n e d in s t a n d a r d versus k n o w n p p m S in standard)

f

(Xl.2)

x f)

lag S =

=

A" s/C

16 g x -106- lag eq g

Therefore,

where: A in. 2 0.1 m V / i n .

F

(xl.1)

mass, g)

(XI.9)

X I . 3 . 4 Derivation with Disk lntegrator--A in Eq X I.6 is expressed as i n ? However, it m a y also be expressed as counts. Therefore, A in. 2 -- counts x 10 -3 since 1 in. 2 = 1000 counts. Therefore, substituting counts x 10 -3 for A in Eq X 1.6 gives lag S = (counts x 1.99 x 10-3)/(R x f )

Therefore,

Then: ppm S =

A x 12 x 10-3 A . s × 16 g x ~106 lag eq g lag S =

(XI.10)

counts x 1.99

R × volume, laL x density, ~

(X 1.4)

inL

R x 96 500.._.. C x A. s eq ~ ×f

xf

p p m S = (counts x 1.99 x 10-3)/(R x mass, g x f ) NOTE X l . l - - C o u n t s

s The value of the Faraday has been redetermined in 1960 by the National Bureau of Standards: the new value is 96 489 + 2 coulombs (chemical scale).

-- 100 x number o f integrator per full-scale

excursions.

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments wi// receive careful consideration at a meeting of the responsible technical committee, which you may attend. If you fee/that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 100 Barr Harbor Drive, West Conshohocken, PA 19428.

493

(1~]~ Designation:D 3205-86 (Reapproved 1991) Standard Test Method for Viscosity of Asphalt with Cone and Plate Viscometer 1 This standard is issued under the fixed designation D 3205; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (~) indicates an e&tonal change since the last revision or reapproval.

1. Scope 1.1 This test method covers the determination of the viscosity of asphalt cements by means of a cone-plate viscometer. It is applicable to materials having viscosities in the range from 10 3 t o 1010 P (102 to 109 Pa.s) and is therefore suitable for use at temperatures where viscosity is in the range indicated. The shear rate may vary between approximately 10-3 to 102 s-1 and the method is suitable for determination on materials having either Newtonian or non-Newtonian flow properties. 1.2 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

assembly which is then brought to the test temperature. Weights acting through a pulley apply torque to the cone and the angular velocity of the cone is measured. Viscosity in poises and shear rate in reciprocal seconds are calculated from the angular velocity, torque, and calibration constants. 4.2 Some asphalt cements may fracture at shear stresses within the range of this instrument. This fracture stress may be reported.

5. Significance and~Use 5.1 The rheological properties of asphalt cements are used for specification purposes for road pavement construction. The instrument provides measurements over a wide range of temperatures for use in research and development of asphalt cements and other bituminous materials.

2. Referenced Documents 2.1 A S T M Standards: C 670 Practice for Preparing Precision and Bias Statements for Test Methods for Construction Materials 2 D 92 Test Method for Flash and Fire Points by Cleveland Open Cup 3

D93 Test Method for Flash Point by Pensky-Martens Closed Cup Tester 3 E 1 Specification for ASTM Thermometers 4

3. Definitions 3.1 viscosity--the resistance to deformation or internal friction of a liquid, expressed as the ratio of shear stress to shear rate, whether this ratio is constant or not. The unit of viscosity obtained by dividing the shearing stress in dynes/ square centimetre by the rate of shear in reciprocal seconds is called the poise. The SI unit of viscosity has the dimensions of pascal-seconds (Pa-s), and is equivalent to 10 P. 3.2 Newtonian liquid a liquid in which the rate of shear is proportional to the shearing stress. 3.3 non-Newtonian liquid a liquid in which the rate of shear is not proportional to the shearing stress. 4. Summary of Method 4.1 The sample is placed between the cone-and-plate t This test method is under the .~unsdiction of ASTM Committee D-4 on Road and Paving Materials and is the direct responsibility of Subcommittee D04.44 on Rheological Tests. Current edition approved Nov. 28, 1986. Published January 1987. Ongmally pubhshed as D 3205 - 73 T. Last previous edttlon D 3205 - 79 (1985). 2 Annual Book of ASTM Standards, Vol 04.02. 3 Annual Book of ASTM Standards, Vol 05.01. 4 Annual Book of ASTM Standards, Vol 14.03.

494

6. Apparatus 6.1 Cone-Plate Viscometer, s'6 as shown in Fig. 1 with metric weights from 10 to 20 000 g. It is used for measuring the viscosities in the range from 103 to 10 I° P (102 to 109 Pa.s) at shear rates from 10 -3 to 10-2 s-l. Important dimensions of each cone and approximate constants are given in Table 1. The approximate data of Table 2 may be helpful in the selection of the proper cone and load. 6.2 Thermometers--Calibrated mercury-in-glass thermometers of suitable range and graduated to 0. I*F (0.05"C). They shall conform to the requirements of Specification E 1. Calibrated ASTM kinematic viscosity thermometers are satisfactory. Other thermometric devices are permissible provided their accuracy, precision, and sensitivity are equal or better than ASTM kinematic viscosity thermometers. 6.3 Bath--A water, alcohol, or ethylene glycol bath suitable for the immersion of the plate and cone and of such height that the cone is immersed to a depth of at least 60 mm. The efficiency of the stirring and balance between heat losses and heat input must be such that the temperature of the water does not vary by more than _.+0.I*F (0.05"C). 6.4 Timer--A stop watch or other timer graduated in divisions of 0.1 s or less and accurate to within 0.01% when tested over intervals of not less than 15 min. Electrical timing devices may be used only on electrical circuits in which frequency is controlled to an accuracy of 0.05 % or better. 6.4.1 Alternating-current frequencies that are intermittently and not continuously controlled, as provided by some 5 Slsko, A. W., "Determination and Treatment of Asphalt Viscosity Data" Highway Research Board, Highway Research Record No. 67, 1965. 6 Manufactured by the Cannon Instrument Co., P.O. Box 16, State College, PA 16801.

(~) D 3205 TABLE 2

MICARTA-~

rrn o1=7 VI=31 I I1 II, / Ik,';'=,,h, ": ..... ,"" ,'""::11 / I "r I

1, 10 -1, and 10 -2 s -1 Cone No. 8

-BRASS

......

2

Angular veloclty,°/s

- ~ hl C O NP'" E I ~SPANNER i

15 24 cm.

=i

NOTE ALL PARTS STAINLESS EXCEPT AS $NOICATED

FIG. 1

Assembly View of Viscometer

public power systems, can cause large errors, particularly over short timing intervals, when used to actuate electrical timing devices. 6.5 O h m m e t e r , or any electrical device capable of indicating that contact between cone and plate is maintained prior to, and during the test.

7. Calibration 7.1 Determine the shear stress constant, K s , the shear rate constant, KD, and the friction correction F, as follows: 7.1.1 To calculate the shear stress constant, K s , proceed as follows: 7.1.1.1 Using an accurate micrometer, measure the cone radius, r (diameter/2) to an accuracy of +_0.05 m m (+0.002 in.). The effective drum radius is the drum radius plus half the string thickness: measure the effective drum radius, R, to an accuracy of +-0.05 m m (+-0.002 in.). Calculate Ks in dynes per (centimetre squared) gram as follows: Ks 3g R/27rr 3 (1) =

where: r = radius of cone, cm, R = effective radius of drum, cm, and g = gravitational constant, 980 dynes/g. 7.1.2 Determine the shear rate constant, K D, for each cone by direct calibration with viscosity standards (see Table TABLE 1

Approximate Instrument Cone Sizes and Constants

Cone No. A

Approximate Cone Radius, cm B

Approximate Cone Angle,

8 4 2

3.75 1.88 0.94

0.5 0.5 05

deg c

Approximate Cone Constant Ks , Ko, deg -1 dynes/cm2.g 2.0 2.0 2.0

100 1000 10000 100 1000 10000 100 1000 10000

4

crn

i

HOLE

Load, g

Approx=mate Viscosities, MP, at Shear Rates of 1 s -1

22

CARDOLOYPLATE -

Approximate Loads and Viscosities at Shear Rates of

495

0.03 0.3 3 0.25 2.5 25 2 2O 200 0.05

0.03 3 30 2.5 25 250 20 200 2000 0.005

(2)

K D = Ks/~m

where: Ks has the value determined in Eq 1, -- viscosity of standard oil, P, and m = slope of regression line resulting from plotting O/t versus L. 7.1.3 Determine the friction correction, F, in grams by one of the following methods: 7.1.3.1 Use the equation: F = L - (1/m)(O/t) (3) where: F = friction correction, g, L = applied load, g, m = slope of the regression line, 0 = measured angle of rotation, deg, and t = measured time of rotation, s. Calculate the value of F for each load point and determine the average. 7.1.3.2 Determine the friction correction F from the plot of 7.1.2 as the intercept with the abscissa.

8. Preparation of Sample 8.1 Heat the sample in an oven at a temperature which is at least 50OF (28°C) below the flash point (Note 1) and in any case not over 3250F (163°C) until it has become sufficiently

Viscosity Standard

A Other cone sizes may be used. a Exact cone and drum redi= must be measured to determine K s by calculation. c Exact cone angle may be calculated from the determination of KD by viscosity standards and measured cone and drum radii. Ko is the reciprocal of the angle between the cone and plate

10 -2 s -1

3 for available calibration standards). This is obtained by the following procedure: 7.1.2.1 Measure the angle of rotation, O, in degrees, and the time, t, in seconds, at applied loads, L, from 5 to 500 g (the range of applied loads will depend on the size of the cone being calibrated). 7.1.2.2 Plot the angular velocity, O/t, in degrees per second, as the ordinate versus the applied load, L, in grams, as the abscissa as shown in the example of Fig. 2. Determine the slope, m, of the line and calculate KD in reciprocal degrees as follows:

TABLE 3

31 250 2000

0.003 0.03 0.3 0.025 0.25 2.5 0.2 2 20 05

1 0 - 1 S- 1

N 30000 A N 190000 A

Viscosity Standards Approximate Viscosity, P At 68°F

At86*F

1500 8000

... ...

A Available in 1-pt containers, price $40.00. F.O.B. State College, PA. Purchase orders should be addressed to Cannon Instrument Co., P.O. Box 16, State College, PA 16804

o a2os i

i

J

]

[

20

40

60

80

I00

10.4 Remove the weight from the top of the shaft. 10.5 Alternative No. / - - M e a s u r e the angular velocity for increasing loads using at least five different weights starting with the smallest and applying them successively at no more than 10-min intervals between each load application. 10.6 Alternative No. 2--Measure angular velocity for decreasing loads using at least five different weights starting with the largest and apply them successively at no more than 10-min intervals between each application. 10.7 Allow the cone to rotate approximately 1° before recording data for each weight. 10.8 The angle of rotation of the cone shall be sufficient to ensure a m i n i m u m time of 20 s, measured to the nearest 0.1 s. While the test is in progress, verify contact between the cone and plate continually or intermittently at frequent intervals, since cone and plate separation may occur as the angle of rotation increases. If contact is lost make the test with a smaller angle of rotation. Select a larger cone and repeat the test starting with 9.3. 10.9 Upon completion of the test, remove the viscometer from the constant-temperature bath. Clean the plate and cone with several rinsings of an appropriate solvent completely miscible with the sample, followed by a completely volatile solvent.

24 c.) L.d

20 (.9 Ld

>:

16

I--

o

12

.J i,i > n.,,

8

< J

4 Z

o

0

WEIGHT, GRAMS FIG.

2

Calibration

of Instrument

fluid to pour, occasionally stirring the sample to aid heat transfer and to assure uniformity. Transfer a m i n i m u m of 200 m L into a suitable container and heat to a temperature of 250 to 300*F (120 to 150"C) (Note 2). After melting thoroughly, stir the sample until it is homogeneous and free of air bubbles. NOTE l - - F l a s h point is defined and determined by either Test Method D 92 or Test Method D 93.

NOTE 2--Sample may be passed through a No. 50 (300-~m) sieve during this transfer.

9. Preparation of Apparatus 9.1 Maintain the bath at test temperature within +0.02*F (0.01*C). Apply the necessary corrections, if any, to all thermometer readings. 9.2 Select the proper size cone to allow measurement of viscosity over a 100-fold shear rate range, preferably at loads of 100, 300, 1000, 3000, and 10 000 g or up to fracture of the sample. (See Table 1 for approximate recommended viscosity ranges for each cone.) 9.3 Place the cone in position in the viscometer, and the plate in place. Tighten the plate firmly, but do not force. 10. Procedure 10.1 Raise the cone and place sufficient hot, prepared sample onto the center of the plate beneath the raised cone. Lower the cone to rest on the sample and place a load of approximately 1000 g on top of the shaft to ensure contact between the cone and plate. 10.2 Place the cone-plate viscometer on a hot plate and allow it to remain there until an ohmmeter, or other electrical device, indicates contact between the cone and plate. Remove the viscometer from the hot plate, allow it to cool until the cone and plate are cool enough to touch. Remove with a non-scratching blade any asphalt on the edge of the cone and on the plate around the cone. 10.3 Place the viscometer in position in the constanttemperature bath. Allow at least 30 min for it to attain the bath temperature. Level the viscometer.

11. Calculation 11.1 Select the calibration factors corresponding to the cone and cord used. For each load and angular velocity, calculate the shear stress, S, in dynes per square centimetre, the shear rate, D, the reciprocal seconds, and the viscosity, n, in poises as follows: S = Ks(L - F) O = KD(O/t) J, = S / D

(4) (5) (6)

12. Report 12.1 Report whether alternative procedure No. 1 or No. 2 was used. 12.2 Report test temperature, viscosity, shear rate and, if fracture occurs, the shear stress resulting in fracture. 13. Precision and Bias 7 13.1 The following precision statement is based on AC 5, AC 10, AC 20, and AC 40 test samples at 25°C at shear rates of 5 x l0 -s, 5 × l0 -2, and 5 × l0 -~ reciprocal seconds. 13.2 The single-operator coefficient of variation has been found to be 3.8 %.8 Therefore, results of two properly conducted tests by the same operator on the same sample using the same viscometer should not differ from each other by more than l 1%8 of their average. 13.3 The multilaboratory coefficient of variation has been found to be 8.4 %.8 Therefore, results of two different laboratories on identical samples of a material should not differ from each other by more than 24 %s of their average. 13.4 No bias can be assigned to this determination. 7 Supporting data are available from ASTM Headquarters. Request RR: D04- 100 I 8 These numbers represent, respectwely, the (IS %) and (D2S %) limits as described m Practice C 670

496

~) D 3205 The American Soctety for Testing and Materials takes no pos~hon respechng the vahdtty of any patent rights asserted Jn connecbon with any Item menboned in th~s standard Users of this standard are expressly advised that determlnatton of the vahdlty of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility This standard Js Sublect to rewslon at any time by the responsible technical committee and must be revtewed every hve years and ff not revised, either reapproved or withdrawn. Your comments are mvtted either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters Your comments wdl receive careful consideration at a meeting of the responstble technical commfftee, which you may attend If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 100 Barr H~rbor Drive, West Conshohocken, PA 19428

497

(~

II1~ INNTII llI I 1~ i.t'rluH rum

DesignatiOn:D 3227 - 960

Art American National Standard

Designation: 342/93

Standard Test Method for Mercaptan Sulfur in Gasoline, Kerosine, Aviation Turbine, and Distillate Fuels (Potentiometric Method) 1 This standard is issued under the fixed designation D 3227; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year &last reapproval. A superscript epsilon (~) indicates an editorial change since the last revision or reapproval.

This standard has been approved for use by agencies of the Department of Defense. Consult the DoD Index of Spec~cations and Standards for the spec~c year of issue which has been adopted by the Department of Defense. This test method has been approved by the sponsoring committee and accepted by the cooperation societies in accordance with established procedures. ~l NffrE--Figure 2 was corrected editorially in April 1997.

1. Scope 1.1 This test method covers the determination of mercaptan sulfur in gasolines, kerosines, aviation turbine fuels, and distillate fuels containing from 0.0003 to 0.01 mass % of mercaptan sulfur (Note 4). Organic sulfur compounds such as sulfides, disulfides, and thiophene do not interfere. Elemental sulfur in amounts less than 0.0005 mass % does not interfere. Hydrogen sulfide will interfere, if not removed as described in 9.2. 1.2 The values in acceptable SI units are to be regarded as the standard. The values in parentheses are for information only. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements, see Notes 1, 2, 3, 5, and 6.

D 4177 Practice for Automatic Sampling of Petroleum and Petroleum Products 4

3. Summary of Test Method 3.1 The hydrogen sulfide-free sample is dissolved in an alcoholic sodium acetate titration solvent and titrated potentiometricaUy with silver nitrate solution, using as an indicator the potential between a glass reference electrode and a silver/silver-sulfide indicating electrode. Under these conditions, the mercaptan sulfur is precipitated as silver mercaptide and the end point of the titration is shown by a large change in cell potential. 4. Significance and Use 4.1 Mercaptan sulfur has an objectionable odor, an adverse effect on fuel system elastomers, and is corrosive to fuel system components. 5. Apparatus 5.1 As described in 5.2 through 5.5; alternatively, any automatic titration system may be used that, using the same electrode pair described in 5.3, is capable of performing the titration as described in Section 9 and selecting the endpoint specified in I0.1 with a predsion that meets or is better than that given in Section 12. 5.2 Meter--An electronic voltmeter, operating on an input of less than 9 x 10-12 A and having a sensitivity of+_2 mV over a range of at least :t:l V. The meter shall be electrostatically shielded, and the shield shall be connected to ground? 5.3 Cell System, consisting of a reference and indicating electrode. The reference electrode should be a sturdy, penciltype glass electrode, having a shielded lead connected to ground. The indicating electrode shall be made from a silver wire, 2 mm (0.08 in.) in diameter or larger, mounted in an insulated support. Silver billet electrodes can also be used.

2. Referenced Documents 2.1 A S T M Standards: D 1193 Specification for Reagent Water 2 D 1250 Guide for Petroleum Measurement Tables 3 D 1298 Test Method for Density, Relative Density (Specific Gravity), or API Gravity of Crude Petroleum and Liquid Petroleum Products by Hydrometer Method 3 D 4052 Test Method for Density and Relative Density of Liquids by Digital Density Meter 4 D4057 Practice for Manual Sampling of Petroleum and Petroleum Products 4 t This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee 1:)02.03 on Elemental Analysis. Current edition approved Dec. 10, 1996. Published February 1997. Originally published as D 3227 - 73. Last previous edition D 3227 - 92. 2 Annual Book of ASTM Standards, Vol I 1.01. 3 Annual Book of ASTM Standards. Vol 05.01. 4 Annual Book of ASTM Standards, Vo105.02.

s Any apparatus that will give equal or better precision will be acceptable.

498

(~ D 3227 6.7 Silver Nitrate, Standard Alcoholic Solution (0.010 mol/L)--Prepare daily by dilution of the 0.1 N standard. Pipet 100 mL of the 0.1 mol/L standard into a I-L volumetric flask and dilute to volume with 2-propanol. Calculate the exact molarity. 6.8 Sodium Sulfide Solution (10 g/L)--Dissolve 10 g of Na2S in water and dilute to 1 L with water. Prepare fresh as needed. 6.9 Titration Solvent--Low molecular weight mercaptans, as usually found in gasoline, are readily lost from the titration solution if an acidic titration solvent is used. For the determination of the higher molecular weight mercaptan as normally encountered in kerosines, aviation turbine fuels and distillate fuels, the acidic titration solvent is used to achieve more rapid equilibrium between successive additions of the titrant. 6.9.1 Alkaline Titration Solvent--Dissolve 2.7 g of sodium acetate trihydrate (NaC2H302.3H20) or 1.6 g of anhydrous sodium acetate (NaC2H302) in 25 mL of oxygenfree water and pour into 975 mL of 2-propanol (99 %) (Note 4). Remove dissolved oxygen by purging the solution with a rapid stream of nitrogen for 10 rain each day prior to use; keep protected from the atmosphere. 6.9.2 Acidic Titration Solvent--Dissolve 2.7 g of NaC2H302"3H20 or 1.6 g of NaC2HaO2 in 20 mL of oxygen-free water and pour into 975 mL of 2-propanol (99 %) (Note 4) and add 4.6 mL of glacial acetic acid. Remove dissolved oxygen by purging the solution with a rapid stream of nitrogen for 10 min each day prior to use; keep protected from the atmosphere. 6.10 Polishing Paper or Cloth, 18 ttm average particle size (800 grit) abrasive.

5.4 Buret, 10-mL capacity, graduated in 0.05-mL intervals, with a tip that extends approximately 120 mm (5 in.) below the stopcock. 5.5 Titration Stand, preferably built as an integral part of the meter housing and provided with supports for the electrodes and electrical stirrer, all connected to ground. No permanent change in meter reading should be noticeable upon connecting or disconnecting the stirring motor.

6. Reagents and Materials 6.1 Purity of Reagents--Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, where such specifications are available. 6 Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination. 6.2 Water--Reagent grade, Type I, Specification D 1193. 6.3 Cadmium Sulfate. Acid Solution (150 g/L)--Dissolve 150 g of cadmium sulfate (3CDSO4.8H20) in water. (Warning--See Note 1) Add 10 mL ofH2SO4 (Warning--See Note 2) (1+5) and dilute to 1 L with water. NOTE 1: Warning--Poison. May be fatal if swallowed or inhaled. A known carcinogen (animal positive). N o t e 2: Warning--Poison. Causes severe bums. Harmful or fatal if swallowed or inhaled.

6.4 Potassium Iodide, Standard Solution (approximately 0.1 mol/L)--Dissolve 17 g of KI (weigh to 0.01 g) in 100 mL of water in a 1-L volumetric flask and dilute to 1 L. Calculate the exact molarity. 6.5 2-Propanol--(Warning--See Note 3).

7. Sampling

NOTE 3: Warning--Flammable.

7.1 Take the sample in accordance with Practice D 4057 or Practice D 4177.

6.6 Silver Nitrate, Standard Alcoholic Solution (0.1 mol/ L)--Dissolve 17 g of AgNO 3 in 100 mL of water in a I-L volumetric flask and dilute to 1 L with 2-propanol (99 %) (Note 4). Store in a dark bottle and standardize at intervals frequent enough to detect a change of 0.0005 or greater in molarity. NOTE 4--It is important to pass the 2-propanol through a column of activated alumina to remove peroxides that may have formed on storage; failure to remove peroxides will lead to low results. It is not necessary to perform this step if the alcohol is tested and found free of peroxides.

8. Preparation of Apparatus 8.1 Glass Electrode--After each manual titration, or batch of titrations, in the case of automatic titration systems, wipe the electrode with a soft, clean tissue and rinse with water. Clean the electrode at frequent intervals (at least once a week) by stirring in cold chromic acid solution (Warning-See Note 6) for a few seconds (10 s max). When not in use, keep lower half of the electrode immersed in water. NOTE 6: Warnlng--Causes severe bums. A recognized carcinogen.

6.6.1 StandardizationmAdd 6 drops of concentrated HNO3 (Tel dens 1.42) (Warning--See Note 5) to 100 mL of water in a 300-mL tall-form beaker. Remove oxides of nitrogen by boiling for 5 min. Cool to ambient temperature. Pipet 5 mL of 0.I mol/L KI solution into the beaker and titrate with the AgNO3 solution choosing the end point at the inflection of the titration curve. NOTE 5: Warning--Poison. Causes severebums. Harmful or fatal if swallowedor inhaled.

Strong oxidizer--contact with other material may cause fire. Hygroscopic. An equivalent, chromium-free cleaning solution may be used. 8.2 Silver/Silver-Sulfide Electrode--Each day prior to use, prepare a fresh silver sulfide coating on the electrode by the following method: 8.2.1 Burnish electrode with polishing paper or cloth until a clean, polished silver surface shows. 8.2.2 Place electrode in operating position and immerse it in 100 mL of titration solvent containing 8 mL of Na2S solution. 8.2.3 Add slowly from a buret, with stirring, 10 mL of 0.1 mol/L AgNO3 solution over a period from 10 to 15 rain. 8.2.4 Remove electrode from solution, wash with water, and wipe with a soft, clean tissue. 8.2.5 Between manual titrations, or batches of titrations

6 Reagent Chemicals, American Chemical Society Spec~cations, American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed by the American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.IC, and the United States Pharmacopeia and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.

499

o 3227 in the case of automatic titration systems, store the electrode a minimum of 5 min in 100 mL of titration solvent containing 0.5 mL of the 0.1 mol/L AgNO3 solution.

Elemental Sulfur + -60C --Excess Mercaptans '~

9. Procedure

9.1 Determination of Density--If the sample is to be measured volumetrically, determine the density by Test Methods D 1298 or D 4052 at the temperature at which the test portion will be taken, either directly or from the density determined at a reference temperature and converted to the transfer temperature by use of the Petroleum Measurement Tables (Guide D 1250). 9.2 Removal of Hydrogen Sulfide--Test the sample qualitatively for hydrogen sulfide (H2S) by shaking 5 mL of the sample with 5 mL of the acid CdSO4 solution. If no precipitate appears, proceed with the analysis of the sample as described in 9.3. If a yellow precipitate appears, remove the H2S in the following manner: Place a quantity of the sample, three to four times that required for the analysis, in a separatory funnel containing a volume of the acid CdSO4 solution equal to one half that of the sample and shake vigorously. Draw off and discard the aqueous phase containing the yellow precipitate. Repeat the extraction with another portion of the CdSO4 solution. Again draw off the aqueous phase, and wash the sample with three 25 to 30-mL portions of water, withdrawing the water al~er each washing. Filter the hydrocarbon through a rapid paper. Test a small portion of the washed sample in a test tube with a few millilitres of the CdSO4 solution. If no further precipitate is formed, proceed as directed in 9.3. If a precipitate appears, repeat the extraction with the CdSO4 solution until all of the H2S has been removed. 9.3 Measure with a pipet or weigh 20 to 50 mL of the original or treated sample into a 300-mL beaker containing 100 mL of the appropriate titration solvent. Place the beaker on the titration stand or on the auto-sampler of an automatic titration system. If an automatic titration system is used, set up the system to reproduce the experimental conditions specified in 9.3.1, 9.3.2, and 9.3.3. Adjust the position of the titration stand so that the electrodes are about half immersed. Fill the buret with 0.01 mol/L alcoholic AgNO 3 solution and position it in the titration assembly so that the tip extends approximately 25 mm (1 in.) below the surface of the liquid in the beaker. Adjust the speed of the stirrer to give vigorous stirring without spattering. 9.3.1 Record the initial buret and cell potential readings. The usual meter readings for mercaptan presence are in the -250 mV to -350 mV range. Add suitable small portions of 0.01 mol/L AgNO 3 solution and, after waiting until a constant potential has been established, record the buret and meter readings. Consider the potential constant if it changes less than 6 mV/min. NOTE 7--If potential readings obtained with freshly prepared electrodes are erratic, it is possible that the electrodes are not properly

conditioned. This difficultyusually disappears in succeedingtitrations. NOTE 8--With certain instruments, the algebraic sign of the potentials may appear reversed. 9.3.2 When the potential change is small for each increment of AgNO3 solution, add volumes as large as 0.5 mL. When the change of potential becomes greater than 6 mY/0.1 mL, use 0.05-mL increments of 0.01 mol/L AgNO3 500

Mercaptans + Excess Sulfur

-400 -t ' ~ Silver Sulfide Mercaptans A l o n e ~ - ~ --. l > -200

o

+200

Sl Iver ~ercaptide

Silver Sulfide

m

+400

Millilitres FIG. 1

of Silver Nitrate

Solution

Illustra~ve PotenUometdc Titration Curves

solution. Near the end point of the titration, 5 or 10 min may elapse before a constant potential is obtained. Although it is important to wait for equilibrium conditions, it is also important that the duration of the titration be as short as possible in order to avoid oxidation of the sulfur compounds by atmospheric oxygen. Once started, a titration must never be interrupted and resumed later. 9.3.3 Continue the titration until the meter reading change of the cell potential per 0.1 mL of 0.01 M A g N O 3 solution has become relatively constant. Consider the potential constant if it changes less than 6 mV/min. Remove the titrated solution, rinse the electrodes with alcohol and wipe with a dry tissue. If an automatic titration system is used, rinse the electrodes well with alcohol, allow the excess alcohol to drain off the electrode; then proceed with the next sample. Between successive determinations (or batches of determinations in the case of automatic titration systems) on the same day, store the electrodes in accordance with 8.1 and 8.2.5. 10. Interpretation of Results

10.1 Treatment of Data--Plot the cumulative volumes of 0.01 M AgNO 3 solution added against the corresponding cell potentials. Select the end point at the most positive value of the steepest portion of each "break" in the titration curve as shown in Fig. 1. The shape of the titration curve may change with different instruments. However, the above interpretation of the end point should be followed. 10.1.1 MercaptansOnly--If mercaptans alone are present in the sample, the titration produces a curve of the first type shown in Fig. 1, having an initial plateau at a potential equal to or more negative than -250 mY, and an end point when a potential change of less than 6 mV/min is reached and the change in mV/min of titrant is reduced with each incremental addition. 10.1.2 Mercaptans and Elemental Sulfur--When elemental sulfur and mercaptans are both present in the sample, a chemical interaction occurs which, in the titration

o a22z 0.0008

m a/i

0.0006

/

u e-

11 0.0004 0

/

/

/

< E

/

/

.,..,,.

E 0.0002 X t~

=E

0.0000 0.000

0.002

0.004

0.006

0.008

0.010

Mercaptan Sulfur, Mass % ---FIG. 2

Repeatability

Reproducibility

Precision Curve for Mercaptan Sulfur in Gasolines, Kerosines, Aviation Turbine, and Distillate Fuels

solvent used, precipitates silver sulfide (Ag2S) during the titration. I0.1.3 When mercaptans are present in excess, the end of the Ag2S precipitation occurs at about -550 to -350 mV, and is followed by the precipitation of the silver mercaptide to the +300-mV end point. This situation is shown in the middle curve of Fig. 1. Since all of the Ag2S originates from an equivalent amount of mercaptan, the total titration to the mercaptide end point must be used to calculate the amount of mercaptan sulfur. 10.1.4 When elemental sulfur is present in excess, the end of the Ag2S precipitation is taken in the same region (+300 mV) as in the case of silver mercaptide, and is calculated as mercaptan sulfur.

12. Precision and Bias 12.1 Precision: 12. I. 1 The precision of this test method as determined by statistical examination ofinterlaboratory results is as follows: 12.1.1.1 Repeatabifity--The difference between two successive test results, obtained by the same operator with the same apparatus under constant operating conditions on identical test material, would in the long run, in the normal and correct operation of the test method, exceed the following values only in one case in twenty: Repeatability 0.00007+ 0.027x (Note 9) where: x = average mercaptan sulfur, mass %. NOTe 9--This amount is shown graphicallyin Fig. 2. 12.1.1.2 Reproducibility--The difference between two single and independent results obtained by different opera. tors working in different laboratories on identical test material would, in the long run, in the normal and correct operation of the test method, exceed the following values only in one case in twenty: Reproducibility 0.00031+ 0.042x (Note 9) where: x = average mercaptan sulfur, mass %. 12.2 B i a s - - T h e bias for the procedure in this test method has not been determined.

11. Calculation 11.1 Calculate the mercaptan sulfur content of the sample as follows: Mercaptan sulfur, mass % -- (AM x 3.206)/W or

Mercaptan sulfur, mass % ffi (AM × 3.206)/(d × It) where: A = miUilitres of AgNO 3 solution required to reach the end point in the vicinity of +300 mV (Fig. 1), d = density of sample at transfer temperature, g/mL, M = molarity of the AgNO 3 solution, W = grams of sample used, 3.206 = 100 x g meq weight S in mercaptan, and V = mL of sample used.

13. Keywords 13. l mercaptan; potentiometric; sulfur

501

o 3227 The American Society for Testing and Materials takes no position respecting the validity of any patent rights esaerted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and # not revised, either reepproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible teshn/cal committee, which you may attend, ff you feel that your comments have not received a fair beefing you should make your views known to the ASTM Committee on Standards, 100 Barr Harbor Drive, West Conshohonkan, PA 19428.

502

(~

Designation:D 3230 - 89

An Amen.an National StandaKl

Standard Test Method for Salts in Crude Oil (Electrornetric Method) 1 This standard is issued under the fixed designation D 3230; the number immediately following the designation indicates the year of original adoption or, in the case &revision, the year of last revision. A number in parentheses indicates the year of last re.approval. A superscript epsilon (E) indicates an editorial change since the last revision or re.approval.

1. Scope 1.1 This test method covers the determination of salts in crude oil. 1.2 The accepted concentration units are pounds NaCI per 1000 bbl of crude oil.

1.3 This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address all of the safety problems associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific precautionary, statements, see 6.3, 6.4, and 6.11. 2. Referenced Documents

2.1 ASTM Standards." D91 Test Method for Precipitation Number of Lubricating Oils 2 D381 Test Method for Existent Gum in Fuels by Jet Evaporation 2 D 843 Specification for Nitration Grade Xylene 3 D 1193 Specification for Reagent Water 5 D4057 Practice for Manual Sampling of Petroleum and Petroleum Products 4 D 4177 Method for Automatic Sampling of Petroleum and Petroleum Products 4 3. Summary of Test Method 3.1 This test method is based on the conductivity of a solution of crude oil in a polar solvent when subjected to an alternating electrical stress (Note 1). The sample is dissolved in a mixed solvent and placed in a test cell consisting of a beaker and two parallel stainless steel plates. An alternating voltage is impressed on the plates and the resulting current flow is shown on a milliammeter. The salt content is obtained by reference to a calibration curve of current versus salt content of known mixtures.

4. Significance and Use 4.1 This test method is used to determine the salt content of crude oils, a knowledge of which is important in deciding whether or not the crude needs desalting. Excessive salt left in the crude frequently results in higher corrosion rates in refining units. 5. Apparatus 5.1 Assemble the appa~tus as described in Annex A 1. 6. Reagents and Materials

6.1 Purity of Reagents--Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, where such specifications are available, e Other grades may be used, provided it is fwst ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination. 6.2 Purity of Water--Unless otherwise indicated, references to water shall be understood to mean reagent water as defined by Type II of Specification D 1193. 6.3 Alcohol Solvent Mixdd Solution, (Warning--See Note 2) Mix 63 volumes of l-butanol and 37 volumes of absolute methanol; to each litre of this mixture, add 3 m L of water. NoTE 2: Warning--Flammable. Liquid causes eye burns. Vapor harmful. May be fatal or cause blindness if swallowed or inhaled. Cannot be made non-poisonous. NoTE 3--The mixed alcohol solvent is suitable for use if its conductivity is less than 0.25 mA when indicated electrode voltage is 125 V a-c. Readings greater than 0.25 mA at 125 V a-c may be due to excessive water in the solvent and indicate that methanol is not anhydrous. 6.4 ASTM Precipitation Naphtha, (Warning--See Note 4), conforming to the requirements of Test Method D 91. NoTE 4: Warning--Extremely Flammable. Harmful if inhaled. Vapors may cause flash fire. 6.5 Calcium Chloride Solution (10 g/L)---Transfer 1.000 g of calcium chloride (CaCI2), or the equivalent weight of a hydrated salt, into a 100-mL volumetric flask and dissolve in 25 mL of water. Dilute to the mark with mixed alcohol solvent. 6.6 Magnesium Chloride Solution (10 g/L)--Transfer 1.000 g of magnesium chloride (MgC12, or the equivalent weight of a hydrated salt), into a 100-mL volumetric flask

Nor~ l--This test method will measure conductivity due to the salts in the crude oil. Calibration curves are based on standards prepared to approximate the type and concentration of salts in the crude oils being tested. l This test method is under the jurisdiction of ASTM Committee 13-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee 1302.03 on Elemental Analysis. Current edition approved Oct. 27, 1989. Published December 1989. Originally published as D 3230 - 73. Last previous edition D 3230 - 83. 2 Annual Book of ASTM Standards, Vol 05.01. 3 Annual Book of ASTM Standards, Vol 06.03. 4 Annual Book of ASTM Standards, Vol 05.03. s Annum Book of ASTM Standards, Vols 06.03 and 11.01.

6 "Reagent Chemicals. American Chemical Society Specification," Am. Chem. Soc., Washington, DC. For suggestions on the testing of reagents not listed by the American Chemical Society, see ~Reagent Chemicals and Standards," by Joseph Rosin, D. Van Nostrand Co., New York, NY and the "United States Pharmacopeia. ~

503

~l~ D 3230 and dissolve in 25 mL of water. Dilute to the mark with mixed alcohol solvent. 6.7 Oil, Refined Neutral--Any refined salt-free oil of approximately 100 SUS viscosity at 38"C (100*F) and free of additive. 6.8 Salts, Mixed Solution (Concentrated Solution)--Com. bine 10.0 mL of the CaC12 solution, 20.0 mL of the MgCI 2 solution, and 70.0 mL of the NaCI solution and mix thoroughly. NOTE 5--The 10:20:70 proportions are representative of the salts present in a wide range of crude oils. When the relative proportions of calcium, magnesium and sodium chlorides are known for a given crude oil, such proportions should be used for most accurate results. 6.9 Salts, Mixed Solution (Dilute Solution)mTransfer 10.0 mL of the concentrated mixed salts solution into a 1000-mL volumetric flask and dilute to the mark with mixed alcohol solvent. 6.10 Sodium Chloride Solution (10 g/L)mTransfer 1.000 g of sodium chloride (NaCI) into a 100-mL volumetric flask and dissolve in 25 mL of water. Dilute to the mark with mixed alcohol solvent. 6.11 Xylene (Warning~See Note 6) nitration grade, conforming to the requirements of Specification D 843. NOTE 6: Warning--Flammable. Vapor harmful.

7. Sampling 7.1 Take the sample in accordance with Practice D 4057, or by Method D 4177.

voltages are applied for high standards. Do not disturb the standardization of the instrument when using other applied voltages. The conductivity of solutions is affected by the temperature at which measurements are made. The temperature of samples at the time of current measurement must be within 3"C (5°F) of the temperature at which the calibration curves were m a d e .

9.2 Run a blank by following the procedure in 9.3 and 9.4 omitting the mixed salts solution. If the indicated electrode current is greater than 0.25 mA at 125 V a-c, water or another conductive impurity is present and its source must be found and eliminated before calibration can be completed. Determine a blank each time fresh xylene or mixed solvent is used. 9.3 Into a dry 100-mL graduated, glass-stoppered mixing cylinder, add 15 m L of xylene. From a to contain pipet add 10 m L of neutral oil. Wash the pipet with xylene until free of oil. Make up to 50 mL with xylene. Stopper and shake the cylinder vigorously for at least 60 s to effect solution. Add a quantity of dilute mixed salts solution in accordance with Table 1 appropriate to the range of salt contents to be measured. Dilute to 100 mL with mixed alcohol solvent. Again shake the cylinder vigorously for 30 s to effect solution and allow the solution to stand 5 rain. Pour the solution into a dry electrode beaker. TABLE 1

8. Standardization of the Electrometric Salt Determinator Instrument

8.1 Connect the electrometric salt determinator instrument (AI.I) to a II0-V, 50 or 60-Hz source. Set toggle switch $2 so that the 25 000 fl (+0.5 %) noninductive precision resistor is in the circuit. Set toggle switch SI to the high scale (H) and turn switch $3 to the ON position. Adjust the voltage to 125 V a-c. Press switch $4 and adjust the 25-fl potentiometer so that the milliammeter is deflected to 0.1 mA. Release switch $4. Change toggle switch S I to the low scale (L). Press switch $4 and adjust the 50-fl potentiometer so that the pointer is deflected to full scale (1.0 mA). Release switch $4. Turn switch $3 to the OFF position. Turn switch $2 to the electrode position. NOTE 7--The low scale (L) is intended for use with samples of low salt content and is thus more sensitivethan the high scale (H). The full scale reading of the milliammeter when toggle switch SI is in the L position is 1.0 mA; full scale meter indication when switch SI is in the H position is 10 mA. 9. Calibration

9.1 The apparatus and procedure are calibrated against solutions of neutral oil and mixed salts solution in xylene because of the extreme difficulties in keeping crude oil-brine mixtures homogeneous. The calibration may be confirmed, if desired, by careful replicate analysis of crude-oil samples by exhaustive extraction of salts with hot water followed by titration of the halides in the extract. In calibrating over a wide range of salt contents, it is necessary to apply voltages other than the standardizing voltage (125 V a-c) to obtain current readings within the limit of the instrument (0 to 10 mA). Higher voltages are applied for low standards and lower

Standard Samples

Salt as NaCI Pounds per 1000 bb~of Crude Oil

Mixed Salts Solution (dilute), mL

1.0 3.0 5.0 10.0 15.0 20.0 25.0 30.0 40.0 50.0 65.0 75.0 85.0 I00.0 150.0

0.3 0.9 1.5 3.0 4.5 6,0 7.5 9.0 12.0 15.0 19.5 22.5 25.5 30.0 45.0

9.4 Immediately place the electrodes in the beaker making sure that the upper edge of the electrode is at least 1/16in. ( 1.6 ram) below the surface of the liquid. Set toggle switch S I to high (H) position. Connect the electrodes to the instrument. Turn switch $3 to ON position. Adjust the indicated electrode voltage to a series of values, for example 25, 50, 125, 200 and 250 V a-c. At each voltage, press $4 and note the miUiammeter reading and record to the nearest 0.01 mA. If the reading becomes less than 0.1 mA, change toggle switch S I to low (L) position. Record the voltage and the corresponding milliammeter reading and continue reading again, recording to the nearest 0.01 mA. Release switch $4. Turn switch $3 to OFF position. Remove electrodes from solution, rinse with xylene followed by naphtha and allow them to dry. NOTE 8: Precaution--ln addition to other precautions, always keep the switch $3 in the OFF position except when the electrodesare in the

504

I1~ D 3230 electrode beaker or when switch $2 is in the calibrate position. The voltage applied to the electrodes may be as great as 250 V a-c, thus hazardous. Accidental short-circuiting of the electrodes may destroy some components of the apparatus.

9.5 Repeat as in 9.3 and 9.4 using other volumes of mixed salts solution (dilute) as needed to cover the range of salt contents of interest. 9.6 Subtract the current reading of the blank from the indicated current readings of the standard samples and plot the salt content (ordinate) against net milliampere reading (abscissa) for each voltage on 3 by 3 cycle log-log paper.

10. Procedure 10.1 To a dry 100-mL graduated, glass-stoppered cylinder add 15 mL of xylene and, by means of a to contain pipet, 10 rnL of crude oil sample. Wash the pipet with xylene until free of oil. Make up to 50 mL with xylene. Stopper and shake the cylinder vigorously for at least 1 rain (Note 9). Dilute to 100 mL with mixed alcohol solvent and again shake vigorously for 30 s. After allowing the solution to stand for 5 rain, pour it into the dry electrode beaker. Follow the procedure in 9.4 to obtain a current reading at the appropriate voltage. Record the indicated electrode current to the nearest 0.01 mA at the voltage. If necessary, record the temperature of the solution (9.1). NOTE 9--Salt brine may be adsorbed on the walls of glass pipets used to measure the sample. If examination of the pipet indicates this

condition, insert the pipet tip beneath the surface of the xylene in the

graduate and allow to drain. Wash the pipet free of the salt brine with mixed alcohol solvent. Raise the pipet from the xyleneand rinse the tip with mixed alcohol solvent. 10.2 Determine the current reading of the blank at the same voltage. 10.3 Subtract the current reading cf the blank at the indicated voltage from the current reading of the sample to obtain the net current reading. From the calibration graph (9.6) read the indicated salt content corresponding to the net milliampere reading of the sample.

11. Precision and Bias 11.1 This test method has been extensively tested in a number of laboratories and found to give results comparable to those from other procedures for determining salt in crude oils. Exact precision data have not been derived because of inability to obtain stable, homogeneous, and representative samples for cooperative testing. 11.2 The responsible ASTM D2.03 study group is currently re-evaluating this test method to determine precision values and to extend the scope of the test method to allow use of modern commercial conductance apparatus. l !.3 The bias for determining the salt content of crude oils by this test method cannot be determined since a suitable standard reference material is not available.

ANNEX

(Mandatory Information) AI. APPARATUS AI.I.6 Potentiometer, 25 t, ten turns. ~ A1.1.7 Potentiometer. 50 t , ten turns. 12

AI.1 Electrometric Salt Determinator (ESD) Components (Fig. AI.I, Note AI.I)

Nor~ A I . I - - A n equivalent part may be substituted in each case provided the electrical characteristics of the entire circuit remain unchanged and that inductive effects and stray currents are avoided.

AI.I.I Milliammeter, 0-1 rnA d-c with 0-1 mA a-c scale, 88 fl internal resistance. 7 AI.I.2 Bridge Rectifier, full-wave, 0.75 A capacity at 60 Hz, ambient temperature; minimum of 400 PRV (Peak Reverse Voltage)) AI.I.3 AC Voltmeter, rectifier type, 2000 t/v, 0 to 300-range. 9 AI.I.4 Variable Voltage Autotransformer, input 105-117 V 50/60 Hz, output 0-132 V, 1.75 A capacity. AI.1.5 Transformer, plate supply 240 V, center tap 50/60 Hz, 250 mA d-c capacity (filament voltage 5 V, 3.0 A not

A1.2 Test Cell Components (Fig. AI.2) AI.2.1 Berzelius Beaker, 100-mL tall form without lip, as described for use in Test Method D 381. A1.2.2 Electrode Assembly, as shown in Figs. AI.2 and AI.3. The electrodes mounted in parallel position, exactly opposed and 0.25 in. (6.4 ram) apart, and electrically separated by a nylon or TFE-fluorocarbon spacer. Care must be exercised in handling the elec~ode assembly to prevent bending or misalignment of the electrodes.

used). '° Weston Model 301, available from Weston Instruments, Inc., 614 Frelinghuysen Ave., Newark, N. J. 07114, has been found satisfactory for this purpose. s Mallory Type FW-400 available from Mallory Industries, Inc., 75 Custer St., West Hartford, Conn. 06090, has been found satisfactory for this p u ~ . 9Weston Model 304, available from Weston Instruments, Inc., 614 Frelinghuysen Ave., Newark, N. J. 07114. t°Stancor P6146, available from Stancor/Electronie, Marketing Division of Essex Wire Corporation, 3501 West Addison St., Chicago, IlL 60618.

i i 25-ohm, 10-turn potentiomcter, linear, 5 watt such as Amphenol Model No. 2200 available from Amphenol, Controls Div., 120 S. Main St., Janesviile, Wis.

53545. 1250-ohm, 10-turn potentiometer, linear, 5 watt such as Amphenol Model No. 2200 available from Amphenol, Controls Div., 120 S. Main St., Janesville, Wis. 53545.

505

@ D 3230 I PIT Switch (PRESS TO MAKE) J

Autoformer S2 ~

~T"~25KJ%

2P2TX~r Pilot L i g h t , - ~ 5A Fuse

S~,

2PI' 3wih 50 "L"

115 VAC 60 Hertz

SI

I IP2T ~>Switch

r

~. ;~ 25 J~. i" "H"

To Electrodes

I0 Turn. 5 Wott Potentlometers FIG. A1.1 250 or 540 Volt Transformer

J ps,,

L,,,.. o,A.o,,.. T.,O. o'.o,,

MAT[RIAL - NYLON OR BETTER

*/z" OIA, • 3/is" O[[P.

--BANANA TIPJACK---~

~

-

~

SPACSR:%" "O.e.T/,e"0.0. .ATeR~L; CA.VASBASS

J //

j,y--'ELEGTRODE SPACER & SCREWS

/ /

~~.250

~-~

BAKeLITe

: ,/s,,~--41114"

MATERIAL ; NON CONDUCTOR SUCH AS NYLON OR SIMI'AR

2

'~ ~_ i/4.

~ SOLOER

II

MATERIAL- 16CA. STAINLEeSSTEEL FIG. A1.3 Electrode Assembly

+ .001

FIG. A1.2 Test Cell 506

APPROX.

~) D 3230 The American Society for Testing and Material8 takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement Of such rights, are entirely their own respot~lbllity. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either respproved or withdrawn. Your comments are invited either for revlalon of thl$ standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful ¢ o r * ~ l o n at a meeting of the respormlble technical committee, whlGh you may attend, ff you feel that your comments have not received 8 fair hearing you shoul¢l make your view= known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103.

507

Designation: D 3235 - 93

An American National Standard

Standard Test Method for Solvent E x t r a c t a b l e s in Petroleum W a x e s 1 This standard is issued under the fixed designation D 3235; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last re.approval. A superscript epsilon (0 indicates an editorial change since the last revision or reapproval.

volume % methyl ethyl ketone and 50 volume % toluene. The solution is cooled to -32°C (-25°F) to precipitate the wax, then filtered. The solvent extractables content is determined by evaporating the solvent from the filtrate and weighing the residue.

1. Scope 1.1 This test method covers the determination of solvent extractables in petroleum waxes. 1.2 The values stated in acceptable metric units are to be regarded as the standard. The values in parentheses are for information only. 1.3 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appro. priate safety and health practices and determine the applicability of regulatory limitations prior to use.

5. Apparatus 5.1 Filter Stick and Assembly, consisting of a 10-mm diameter sintered glass filter stick of 10 to 15 ~m maximum pore diameter as determined by the method in the Appendix, provided with an air pressure inlet tube and delivery nozzle. It is provided with a ground-glass joint to fit a 25 by 170-ram test tube. The dimensions for a suitable filtration assembly are shown in Fig. 1.

2. Referenced Documents

2.1 A S T M Standards." D 740 Specification for Methyl Ethyl Ketone 2 D 841 Specification for Nitration Grade Toluene 2 D 1078 Test Method for Distillation Range of Volatile Organic Liquids 2 D 1218 Test Method for Refractive Index and Refractive Dispersion of Hydrocarbon Liquids 3 D 1364 Test Method for Water in Volatile Solvents (Fischer Reagent Titration Method) 2 D 1613 Test Method for Acidity in Volatile Solvents and Chemical Intermediates Used in Paint, Varnish, Lacquer and Related Products 2 E I Specification for ASTM Thermometers 4 E 128 Test Method for Maximum Pore Diameter and Permeability of Rigid Porous Filters for Laboratory Use 5 2.2 IP Standard." Colour, Lovibond, IP 17, Method B

NOTE I - - A metallic filter stick may be employed if desired. A fdter stick ) made o f stainless steel and having a 12.7-ram (0.50-in.) disk o f 10 to 15 n m m a x i m u m pore diameter, as determined by Test Method E 128, has been found to be satisfactory. The metallic apparatus is inserted into a 25 by 150-ram test tube and held in place by means o f a cork.

5.2 Cooling Bath, consisting of an insulated box with 25.4-mm (l.00-in.) holes in the center to accommodate any desired number of test tubes. The bath may be filled with a suitable medium such as kerosine, and may be cooled by circulating a refrigerant through coils, or by using solid carbon dioxide. A suitable cooling bath to accommodate three test tubes is shown in Fig. 2. 5.3 Dropper Pipet, provided with a rubber bulb, and calibrated to deliver 0.5 + 0.05 g of molten wax. 5.4 Transfer Pipet, calibrated to deliver 15 + 0.06 mL. 5.5 Air Pressure Regulator, designed to supply air to the filtration assembly (8.5) at sufficient pressure to give an even flow of filtrate. Either a conventional pressure-reducing valve or a mercury bubbler-type regulator has been found satisfactory. The latter type, illustrated in Fig. 3, consists of a 250-mL glass cylinder and a T-tube held in the cylinder by means of a rubber stopper grooved at the sides to permit the escape of excess air. The volume and pressure of the air supplied to the filtration assembly is regulated by the depth to which the T-tube is immersed in mercury at the bottom of the cylinder. Absorbent cotton placed in the space above the mercury prevents the loss of mercury by spattering. The air

3. Significance and Use 3. I The solvent extractables in a wax may have significant effects on several of its properties such as strength, hardness, flexibility, scuff resistance, coefficient of friction, coefficient of expansion, melting point, and staining characteristics. Whether these effects are desirable or undesirable depends on the intended use of the wax. 4. Summary of Test Method 4.1 The sample is dissolved in a mixture consisting of 50 i This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.10 on Properties of Petroleum Wax. Current edition approved Sept. 15, 1993. Published November 1993. Originally published as D 3235 - 73. Last previous edition D 3235 - 88. 2 Annual Book of ASTM Standards, Vol 06.03. 3 Annual Book of ASTM Standards, Vol 05.01. 4 Annual Book of ASTM Standards, Vol 05.03. 5 Annual Book of ASTM Standards, Vol 14.02.

6 Available from the Institute of Petroleum, 61 New Cavendish St., London, W.I, England. 7 A suitable metal filter stick with designated porosity G may be obtained from the Pall Trinity Micro Corp., Route 281, Cortland, NY 13045. A list of United Kingdom suppliers can be obtained from the Institute of Petroleum, 61 New Cavendish St., London, W. I, England.

508

o 323s 35-45

65-75

19-21/D

-

-

~:5~73"5--ID-

IN DIRECTIONOFARROW • 25 ODCOOLINGTUBE

.~

__t~J

SINTEREDGLASSDISK

-~-~ 9-11 DIA. All dimensions are in mlUimetres

FIG. 1 Filter Stick

pressure regulator is connected to the filter stick and assembly by means of rubber tubing. 5.6 Thermometers, two, having a range as shown below and conforming to the requirements as prescribed in Specification E 1 or in the specifications for IP Standard Thermometers. One thermometer is required for the cold bath and a second thermometer is required for the sample solution. Thermometer Number

Range

ASTM 7IF IP 72C IP 72F

-35 to +70"F -32 to +21"C -35 to +70"F

and capable of maintaining a temperature of 35 ± I°C (95 ± 2"F) around the evaporation flasks. Construct the jets with an inside diameter of 4 ± 0.2 mm for delivering a stream of clean, dry air vertically downward into the weighing bottle. Support each jet so that the tip is 15 + 5 mm above the surface of the liquid at the start of the evaporation. Supply air at the rate of 2 to 3 L/rain per jet, purified by passage through a tube of 1-cm bore packed loosely to a height of 20 cm with absorbent cotton. Periodically check the cleanliness of the air by evaporating 4 mL of the solvent mixture described in 6.3 by the procedure specified in 8.5. When the residue does not exceed 0.1 rag, the evaporation equipment is operating satisfactorily.

5.7 Weighing Bottles, conical in shape and glass-stop pered, having a capacity of 15 mL. 5.8 Evaporation Assembly, consisting of an evaporating cabinet and connections, essentially as illustrated in Fig. 4,

NOTE 2--Investigations by the European World Federation have indicated that improved precision may be achieved by individually calibrating each nozzle to deliver a flow rate of 2 to 3 L/rain. 5.9 Analytical Balance, capable of reproducing weights to 0.1 rag. The sensitivity should be adjusted so that 0.1 mg will deflect the pointer one half division on the pointer scale. 5. I O Wire StirreruA piece of stiff iron or Nichrome wire of about 0.9 mm in diameter (No. 20 B&S or 20 swg), 250 mm long. A 10-mm diameter loop is formed at each end, and the loop at the bottom end is bent so that the plane of the loop is perpendicular to the wire.

TABLE 1 Specifications for Methyl Ethyl Ketone Property

Specificgravity,20/20°C Color Distillationrange: Below78°C Above81°C Acidity Water content Residue on evaporation

Refractive index at 20°C

(8S'F)

Value 0.805 to 0.807 water white, 1.0 max nil nil 0.003 weight%, max (expressed as acetic acid) 0.3 weight Yo, max residue remaining after evaporation of 4 ml by procedure in 8.5 shall not exceed 0.1 mg 1.378 + 0.002

Method IP 17 (B) ASTM D 1078 ASTM D 1613

6. Solvent

ASTM D 1364

6.1 Methyl Ethyl Ketone, conforming to Specification D 740, or to Table 1. 6.2 Toluene, conforming to Specification D 841. 6.3 Solvent MixtureuPrepare a mixture of 50 volume % methyl ethyl ketone and 50 volume % toluene.

ASTM D 1218

509

~I~ D 3235

THERMOMETER

AIR PRESSURE

ASTIC

dNER Lcr)

CAPACITY FILLED WITH COOLING

MEDIUM

203

"~

(8'¢0

All dimensions e r e In milllmetres (inches) FIG. 2

Cooling Bath

6.4 Store the solvent mixture over anhydrous calcium sulfate (5 weight % of the solvent). Filter prior to use.

nearest 1 mg (Note 3). Swirl the test tube so as to coat the bottom evenly with wax. This permits more rapid solution later. Allow the test tube to cool, and weigh to the nearest 1 rag.

7. Sample 7.1 Obtain a representative portion by melting the entire sample and stirring thoroughly. This is necessary because the extractables may not be distributed uniformly throughout the solidified sample.

NOTE 3~The weight of a test tube which is cleaned by means of solvent will not vary to a significantextent. Therefore,a tare weightmay be obtained and used repeatedly. 8.2 Pipet 15 ml of the solvent mixture into the test tube and place the latter just up to the level of its contents in a hot water or steam bath. Heat the solvent-wax mixture, stirring up and down with the wire stirrer, until a homogeneous solution is obtain. Exercise care to avoid loss of solvent by prolonged boiling.

8. Procedure 8.1 Melt the representative sample in a beaker, using a water bath or oven maintained at 70 to 100"C (160 to 210°F). As soon as the wax is completely melted, thoroughly mix by stirring. Preheat the dropper pipet in order to prevent the solidification of wax in the tip, and withdraw a 0.5-g portion of the sample as soon as possible after the wax has melted. Hold the pipet in a vertical position, and carefully transfer its contents into a clean, dry test tube previously weighed to the

NOTE 4--Very high-meltingwax samples may not form clear solutions. Stir until the undissolvedmaterial is welldispersedas a fine cloud. 8.2.1 Plunge the test tube into an 800-mL beaker of ice water and continue to stir until the contents are cold. 510

@ D 3235 AIR PRESSURE ~ !

ABSORBENT

COTTON-

MERCUR~

.

FILTER )....,--I ~TO ASSEMBLY

i ~ R U B B E R STOPPER

1

WITHAIRVENT

--.---GLASSTUBINO 6-80.D;'

250mlGLASS CYI.INOER

All dimensionsare in mJllimetres FIG. 3 Air Pressure Regulator

Remove the stirrer. Remove the test tube from the ice bath, wipe dry on the outside with a cloth, and weigh to the nearest 0.1g. NOTE 5--During this operation the loss of solvent through vaporization should be less than 1%. The weight of the solvent is, therefore, practically a constant, and, after a few samples are weighed,this weight can be used as a constant factor. 8.3 Place the test tube containing the wax-solvent slurry in the cooling bath, which is maintained at -34.4 ± I*C (-30 ± 2*F). During this chilling operation stir the contents of the tube by means of a thermometer placed in the tube. It is important that stirring by means of the thermometer be almost continuous, in order to maintain a slurry of uniform consistency as the wax precipitates. Do not allow the wax to set up on the walls of the cooling vessel nor permit any lumps of wax crystals to form. Continue stirring until the temperature reaches -31.7 ± 0.3"C (-25 ± 0.5*F). 8.4 Remove the thermometer from the tube and allow it to drain momentarily into the tube, then immediately immerse in the mixture the clean, dry filter stick, which has previously been cooled by placing it in a test tube and holding at -34.4 ± l*C (-30 -+ 2*F) in the cooling bath for a minimum of 10 rain. Seat the ground-glass joint of the filter so as to make an airtight seal. Place an unstoppered weighing

bottle, previously weighed together with the glass stopper to the nearest 0.1 mg, under the delivery nozzle of the filtration assembly. NOTE 6--Take everyprecautionto ensure the accuracyof the weight of the stoppered weighingbottle. Prior to determiningthis weight, rinse the clean, dry weighing bottle and stopper with the solvent mixture described in 6.3, wipe dry on the outside with a cloth, and place in the evaporationassemblyto dry for about 5 rain. Then removethe weighing bottle and stopper, place near the balance,and allowto stand for 10 rain prior to weighing.Stopperthe bottle during this coolingperiod. Once the weighing bottle and stopper have been dried in the evaporation assembly, lift only with forceps. Take care to remove and replace the glass stopper with a light touch. 8.5 Apply air pressure to the filtration assembly and immediately collect about 4 mL of filtrate in the weighing bottle. Release the air pressure to permit the liquid to drain back slowly from the delivery nozzle. Remove the weighing bottle immediately, and stopper and weigh to the nearest 10 mg without waiting for it to come to room temperature. Unstopper the weighing bottle and place it under one of the jets in the evaporation assembly maintained at 35 ± I'C (95 ± 2*F), with the air jet centered inside the neck, and the tip 15 + 5 mm above the surface of the liquid. After the solvent has evaporated, which usually takes less than 30 min, remove the boRIc, stopper, and place near the balance. Allow to stand for 10 rain and weigh to the nearest 0.1 mg. Repeat the evaporation procedure, using 5 min evaporation periods, until the loss between successive weighings is not over 0.2 mg. 9. Calculation 9.1 Calculate the amount of extractables in the wax as follows: Solvent extractables, weight % = 100 AC/BD where: A = weight of extractables residue, g, B ffi weight of wax sample, g, C ffi weight of solvent, g, obtained by subtracting weight of test tube plus wax sample (8.1) from weight of test tube and contents (8.2), and D = weight of solvent evaporated, in g, obtained by subtracting weight of weighing bottle plus extractables residue from weight of weighing bottle plus filtrate (8.5). 10. Report 10.1 Report the result as solvent extractables, weight %, ASTM Test Method D 3235. If the result is negative, report as zero.

511

0

a2a5

o

~

HALF SECTION A-A

|

FF.RFORATEDMETAL PLATFORM 6.5 (Y4) DIA HOLES

EATI~R CONTROl.

i

ILT£R£D

HALF SECTION ' a - a ' All dimensions are in milllmetres

Orghee)

FIG. 4 Evaporation Assembly

single and independent results obtained by different operators working in different laboratories on identical test material would, in the long run, in the normal and correct operation of the test method, exceed the following values only in one case in twenty: Range Reproducibility 15to 55 % 5% 1 1.2 The procedure in this test method has no bias because the value of solvent extractables can be defined only in terms of a test method.

11. Precision and Bias 11.1 The precision of this test method as determined by statistical examination of interlaboratory results is as follows: 11.1.1 Repeatability--The difference between two test results, obtained by the same operator with the same apparatus under constant operating conditions on identical test material would, in the long run, in the normal and correct operation of the test method, exceed the following values only in one case in twenty: Range Rew..atability 15to55% 2% 11.1.2 Reproducibility--The difference between two

12. Keywords 12.1 petroleum waxes; solvent extractables; wax

512

~@) D 3235

APPENDIX

(Nonmandatory Information) Xl. T E S T M E T H O D OF TEST FOR M E A S U R E M E N T OF M A X I M U M PORE DIAMETER O F RIGID P O R O U S FILTERS X l . l Scope

surface tension of water and the applied pressure.

X l.l.1 This method covers the determination of the acceptability of porous filter sticks used for filtration in Method D 3235. This method establishes the maximum pore diameter and also provides a means of detecting and measuring changes which occur from continued use.

X1.4 Apparatus XI.4.1 Manometer, mercury filled and readable to 0.5 mm. XI.4.2 Air Supply, clean and filtered. X1.4.3 Air Pressure Regulator, needle-valve type. XI.4.4 Drying Oven.

Xl.2 Terminology X 1.2.1 Definition X1.2.2 maximum pore diameteruthe diameter nanometres of the largest opening in the filter.

X1.5 Procedure XI.5.1 Clean the filter sticks by soaking in concentrated hydrochloric acid, and then wash them with distilled water. Rinse with acetone, air dry, and place in drying oven at 220"F (105"C) for 30 rain. XI.5.2 Thoroughly wet the clean filter to be tested by soaking it in distilled water. XI.5.3 Assemble the apparatus as shown in Fig. XI.I. Apply pressure slowly from a source of clean air. XI.5.4 Immerse the falter just below the surface of the water. NoTE X 1.2--If a head of liquid exists above the surface of the filter, the back pressure produced must be deducted from the observed

in

NOTE X i.l--lt is recognized that the maximum pore diameter as defined herein does not necessarilyindicate the physical dimensions of the largest pore in the filter. It is further recognizedthat the pores are highly irregular in shape. Because of the irregularityin shape and other phenomena characteristicof filtration, a filter may be expected to retain all particles larger than the maximum pore diameter as defined and determined herein, and will generally retain particles which are much smaller than the determined diameter. Xl.3 Summary of Test Method X I.3.1 The filter is cleaned and wetted with water. It is then immersed in water and air pressure is applied against its upper surface until the first bubble of air passes through the filter. The maximum pore diameter is calculated from the Source of Air

pressure.

X1.5.5 Increase the air pressure to 10 m m below the acceptable pressure limit and then at a slow uniform rate of about 3 mm Hg/min until the first bubble passes through the filter. This can be conveniently observed by placing the beaker or test tube over a mirror. Read the manometer when the first bubble passes off the underside of the filter.

>e---Air Filter i:~--- Regulating Valve ::

X1.6 Calculation X 1.6.1 Calculate the pore diameter as follows:

Drying Bulb

D Filter Stick

=

2180/p

where: D -- pore diameter, nm, and p = manometer reading, m m Hg. NOTE Xl.3--From this equation, pressure corresponding to the upper and lower limits of the specifiedpore diameters can be calculated. These pressures may be used for acceptance t~tin$.

•' Manometer - ~

Beaker of Water

FIG. X1.1 Assembly of Apparatus for Checking Pore Diameter or Filter Sticks

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any ouch patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103.

513

(~~Ti~ Designation: D 3239 - 91

An Amencan Nahonal Standard

Standard Test Method for Aromatic Types Analysis of Gas-Oil Aromatic Fractions by High Ionizing Voltage Mass Spectrometry This standard is issued under the fixed designation D 3239; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number m parentheses indicates the year of last reapproval. A superscript epsilon (~) indicates an editorial change since the last revision or reapproval.

1. Scope 1.1 This test method 2 covers the determination by high ionizing voltage, low resolution mass spectrometry of 18 aromatic hydrocarbon types and 3 aromatic thiophenotypes in straight run aromatic petroleum fractions boiling within the range from 205 to 540"C (400 to 1000*F) (corrected to atmospheric pressure). Samples must be nonolefinic, must contain not more than I mass % of total sulfur, and must contain not more than 5 % nonaromatic hydrocarbons. Composition data are in volume percent.

Z78 -- 78 + 92 + 106 + 120 + . . t o end, polyisotopic + 91 + 105 + 119 + . . t o end, monoisotopic

NOTI~ I - - A l t h o u g h n a m e s are g i v e n to 15 o f the c o m p o u n d types

ZI28 = 128 + 142 + 156 + 170 + . . t o end, polyisotopic + 141 + 155 + 169 + . . t o end, monoisotopic

(I)

3. I. 1.3 Class IL" Z104 = 104 + 118 + 132 + 146 + . . t o end, polyisotopic + 117 + 131 + 145 + . . t o end, monoisotopic

(2)

3.1.1.4 Class III. ~;129 = 130 + 144 + 158 + 172 + . . t o end, polyisotoplc + 129 + 143 + 157 + 171 + . . t o end, monoisotopic

(3)

3. I. 1.5 Class IV."

determined, the presence of other compound types of the same empirical formulae is not excluded. All other compound types in the sample, unidentified by name or empirical formula, are lumped into six groups in accordance with their respective homologous series.

(4)

3.1.1.6 Class V: z i 5 4 = 154 + 168 + 182 + 196 + . . t o end, polyisotopic + 167 + 181 + 195 + . . t o end, monoisotopic

1.2 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safely and health practices and determine the applicability of regulatory limitations prior to use.

(5)

3. I. 1.7 Class VI: Z 166 = 166 + 180 + 194 + 208 + . . to end, polyisotopic + 179 + 193 + 207 + . . t o end, monoisotopic

(6)

3.1.1.8 Class VII:

1~3 The values stated in acceptable SI units are to be regarded as the standard. The values given in parentheses are provided for information purposes only.

~;178 = 178 + 192 + 206 + 220 + . . t o end, polyisotopic + 191 + 205 + 219 + . . t o end, monoisotopic

2. Referenced Documents

3.1.2 Classes, Compound Types, Empirical Formulae-See Table I.

(7)

2.1 A S T M Standards: D 2 5 4 9 Test Method for Separation of Representative Aromatics and Nonaromatics Fractions of High-Boiling Oils by Elution Chromatography 3 D 2786 Test Method for Hydrocarbon Types Analysis of Gas-Oil Saturate Fractions by High Ionizing Voltage Mass Spectrometry 3 E 137 Practice for Evaluation of Mass Spectrometers for Quantitative Analysis from a Batch Inlet 4

4. Summary of Test Method 4.1 The relative abundance of seven classes (I-VII) of aromatics in petroleum aromatic fractions is determined by mass spectrometry using a summation of peaks most characteristic of each class. Calculations are carried out by the use o f a 7 by 7 inverted matrix derived from published spectra of pure aromatic compounds. Each summation of peaks includes the polyisotopic homologous series that contains molecular ions and the monoisotopic homologous series one mass unit less than the molecular ion series. Using characteristic summations found in the monoisotopic molecular i o n - - I series of peaks, each class is further resolved to provide relative abundances of three c o m p o u n d types: nominal (Type 0), first overlap (Type l), and second overlap (Type 2). The aromatic fraction is obtained by liquid elution chromatography (see Method D 2549).

3. Terminology 3.1 Descriptions of Terms Specific to This Standard: 3.1.1 Characteristic Mass Summations--Classes I- VII: 3.1.1.2 Class I: This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Prtxtucts and Lubricants and is the direct rcsponslbdlty of Subcommittee D02.04 on Hydrocarbon Analysis. Current edition approved Oct. 15, 1991. Published December 1991. Originally published as D 3239 - 73 T. Last previous edition D 3239 - 86. : Robinson, C. J., and Cook, G. L., Analytical Chemi,stry (ANCHA), Vol 41, 1969, p. 1548. a,.lnmtal Book o/ASTM Standards, Vol 05.02. "~Annual Book of ASTM Standards', Vol 05.03.

NOTE 2--Monoisotopic peaks heights are obtained by correcting the polyisotopic heights for naturally occurring heavy isotopes, assuming that only ions of C,,H:,,+ 2 to C,,H2_~ are present. This is not strictly accurate for aromatics, but the errors introduced by such assumption are trivial. 514

~1~ O 3239 TABLE 1

Classes, Compound Types, and Empirical Formulae

Class

Type

I I I II II II Ill III III IV IV IV V

0 1 2 0 1 2 0 1 2 0 1 2 0

V V Vl VI VI VII VII VII

1 2 0 1 2 0 1 2

8. Calibration 8.1 Calibration equations in the computer program given in Table 2 may be used directly provided the following procedures are followed: 8.1.1 Instrumental Conditions--Repeller settings are adjusted to maximize the m/e 226 ion of n-hexadecane. A magnetic field is used that will permit a scan over the mass range from 78 to 700. An ionizing voltage of 70 eV and an ionizing current in the range from 10 to 70 p.A is used. NOTE 4--The instrument conditions and calibration equations described in this method are based on the use of a 180"magnetic-deflection type mass spectrometer (CEC Model 21-103). Satisfactory results have been obtained with some other magneticdeflectioninstruments. It is not known if the equations are suitable for use on all other mass spectrometer types. 8.1.2 Computer ProgramRThe FORTRAN program given in Table 2 contains all the equations for calculating the analysis, including those for calculating monoisotopic peak heights. The program is compiled and linked to create a computer load module that is available whenever needed. When the spectrum shown in Table 3 is processed, the results should agree with those shown in Table 4. 8.1.2.1 Data Input FormatRThe input format suggested in the main program may be changed to suit the needs of individual laboratories provided that true masses and peak heights are stored in the H(M) array. 8.1.2.2 FORTRAN IV Language~Changes in the program may be required for compatibility with the particular computing system to be used. These are permitted provided that the altered program gives the results shown in Table 4 with the input data of Table 3. NOTE 5--The program, as shown in Table 2, has run satisfactorilyon IBM System 360 computers.

Formula

alkylbenzenes, CnH2n.6 benzothiophenes, CnH2n.loS naphthenephenanthrenes, CnH2~.20 naphthenebenzenes, CnH2n-a pyrenes, CnH2n-22

unidentified dinaphthenebenzenes, CnH2n.10 chrysenes, CnH2n.24 unidentified naphthalenes, CnH2n.12 dibenzothiophenes, CnH~.16S unidentified acenaphthenes + dibenzofurans, C.H2n.14 and OnH2n.160

perylenes, CnH2n.28 unidentified fluorenes, CnH2n.16

dibenzanthracenes, CnH2n.3O unidentified phenanthrenes, CnH2..la naphthobenzothiophenes, CnH2,,.22S

unidentified

5. Significance and Use 5.1 A knowledge of the hydrocarbon composition of process streams and petroleum products boiling within the range 205 to 540"C (400 to 1000*F) is useful in following the effect of changes in process variables, diagnosing the source of plant upsets, and in evaluating the effect of changes in composition on product performance properties. This method, when used together with Method D 2786, provides a detailed analysis of the hydrocarbon composition of such materials. 6. Apparatus

9. Procedure 9.1 If the mass spectrometer has been in continuous operation, no additional preparation is necessary before analyzing samples. However, if the spectrometer has been turned on only recently, check its operation according to the manufacturer's instructions to ensure stability before proceeding. 9.2 Obtain the mass spectrum of the sample, scanning from mass 76 to the high-mass end of the spectrum.

6.1 Mass Spectrometer--The suitability of the mass spectrometer to be used with this method shall be proven by performance tests described both herein and in Recommended Practice E 137. 6.2 Sample Inlet System--Any inlet system may be used that permits the introduction of the sample without loss, contamination, or change in composition. The system must function in the range from 125 to 350"C to provide an appropriate sampling device. 6.3 Microburet or Constant- Volume Pipel. 6.4 Mass Spectrum Digitizer--It is recommended that a mass spectrum digitizer be used in obtaining the analysis, because it is necessary to use the heights of most of the peaks in the spectrum. Any digitizing system capable of supplying accurate mass numbers and peak heights is suitable. 6.5 Electronic Digital Computer--The computations for this analysis are not practical without the use of a computer. Any computer capable of providing approximately 60 K bytes in core and capable of compiling programs written in FORTRAN IV should be suitable.

10. Calculations 10.1 Recording Mass Spectrum--Read peak heights and the corresponding masses for all peaks in the spectrum of the sample. Use the data, along with sample identification, as input to the computer.

11. Precision and Bias 11.1 The precision of this test method as obtained by statistical examination of interlaboratory test results on a sample having the composition given in Table 5, is as follows: 11.1.1 Repeatability--The difference between successive test results obtained by the same operator with the same apparatus under constant operating conditions on identical test material, would in the long run, in the normal and correct operation of the test method, exceed the values shown in Table 5 only in one case in twenty.

7. Reagent

7.1 n-Hexadecane NOTE 3: Warning--Combustible-Very harmful.

515

~ TABLE 2

D 3239

High Ionizing Voltage, Low Resolution Mass Spectrometric Analysis of Gas Oil Aromatic Fractions

"The "end statement" designated is specific for IBM computers. The user may modify the FORTRAN program to suit his individual needs. IN THIS PROGRAM THE VARIABLE "H(M)" REPRESENTS THE HEIGHT OF THE POLYISOTOPIC PEAK AT MASS M, THE VARIABLE "HDI(M)" IS THE HEIGHT OF THE DEISOTOPED PEAK AT MASS M, THIS IS A POSSIBLE MAIN PPOGRAM THAT REAOS INPUT DATA AND CALLS FIRST THE DEISOTOPING ROUTINE "SUBROUTINE OEISO" AND THEN THE CALCULATING AND REPORTING ROUTINE "SUBROUTINE AROMTC", COMMON TITLE(20), H(75R)~ HDI(7~B) DIMENSION MASS(B)t HITE(8) 1 READ(5~IO,~NO=gg)(TITLE(1),I=],~O) 10 FORMAT(2OA~) TITLE CARD FOR SAMPLE NAMEr ETC, PRECEDES SPECTRAL DATA CARDS, FOPMAT FOR TITLE IS 20A~ (?0 4-CHARACTER WORDS IN RO COLUMNS), FORMAT FOR SPECTRAL DATA IS MASS (16) FOLLOWED BY HEIGHT (F~,O) WITH B PEAKS PE~ RO-COLUMN CARD, DO 50 I=12,75~ H(I) = 0,0 50 HDI(1) = 0,0 30 REAO(5,40)(MASS(I),HITF(1)~I=I,~) 40 FORMAT(B(16,r4,0)) DO 50 I=I,R IF(MASS(1),Ea,aqqqqa)GO TO 60 ENTER " g g g q D q "

IN A MASS POSITION 0~; A CAPD TO DENOTE SPECTRUM END.

IF(MASS(1),EO,n)GO TO 50 M = MASS(1)

H(M) = HITF(1) 50 CONTINUE GO TO 30 ~0 CALL DEISO CALL ARONTC ~0 TO 1 ,,GO TO I " ALLOWS SUCCESSIVE SAMPLES TO BE COMPUTEr BEFORE RELEASING COMPUTE R,

99 STOP ENn SUBROUTINE DEISO THIS ~URROUTINE COMPUTES MONOISOTOPlC PEAKS ASSUMING ALL IONS HAVE Z NIIMREPS FROM +2 TO - ] ! IN THE FORMULA C(N)H(2N + Z), COMMON TITLE(20), H(758)~ HDI(75B) ~IMENSION NCAQR(75R)~ NHYD(75R) DO I0 I=12,758 NCARR(1) = 0 I0 NHYO(1) = 0 O0 20 K=12,75R NCARR(K) = (K + 11}/14 NHYD(K) = K - 12*NCARB(K) IF(NHYn(K).LT,O)NHYD(K) = 0 2O CONTINUE DO 30 K=I4,TSR HDI(K) = H(K)-HDI(K-I)~(.OIOBII*FLOAT(NCARB(K-I))+,OOOI5*FLOAT I(NHYD(K-I))) HOI(K) = HDI(K)+HDI(K-2)*(,OOOOSB~4OFLOAT(NCAQB(K-2)t(I-NCARB(K-2) I))+.IIPSE-7*FLOAT(NHYO(K-2)*(I-NHYD(K-~)))-,16PI65E-SoVLOAT(NCARR( 2K-~)*NHYD(K-~)}) IF(HDI(K),LT,O,O)HDI(K) = 0.0 30 CONTINUE RETURN END

516

~

D 3239

TABLE 2

Continued

SUBROUTINE AROMTC C C THIS QOUTINE GIVES THE ANALYSIS OF AROMATICS FRACTIONS FROM PETROLEUM C USING THE RRnCEDURE DESCRIBED IN ANAL CHEM 41t 1 5 4 8 - 5 4 ( 1 9 6 9 ) C COMMON T I T L E ( 2 0 ) ~

H(75R)t

HOI(758)

DIMENSION A/N(797), ~ A t 7 ) t BB(7)~ SR(75R) DATA AIN / + 1 . 8 0 q ~ , - . l q 5 2 ~ + . O l ~ 4 , - . O O Z I , - . O O l S , - . O n 1 1 , - . O 0 2 ~ , 2 -.1601.+2.047qt-.2806~-.O~Ol.+.OOB2,+.On]2,+.o00~.

C C

3

-.0943,-.2287~+2.~024,-.4q3~,-.0601~-.01559-.00~,

4 5 6

-.0292~*.0033,-.N580,+1.9404,-.1337,-.0]17,-.0043,

7

-.2346~-,106Q,-.O267,-.OOlq~-.O057,-,0904~+l.9904/

-.On~2t-,O003,-oO026,-.O195,+].9773,-.l~23,+.0123~

-.0420~÷,O0~6,-.OOlS,-.OlSl,-.O~84,÷?,0616t-.41q3, INITIALIZE SQUARE RO~T ARPAY

C DO 2132 I=]2,750 2132 SP(I) = 0.0 ASSEMBLE APPROPRIATT P~AKS IN ~ASS SPECTRUM OF AROMATIC FPACTIhN FOR PROCESSING IN A 7 X 7 MATRIX. QUANTITIES A6~aI~AS,ETC, REFER INITIALLY TO SUMS OF PEAKS AT Z NUMBERS 6~7~8,ETC. A6~AB,~TC. ARE LATER REDEFINED TO INCLUDE THE ODD Z-NUMBER SUM CORRESPONDING TO THE PARENT-] SERIES (A6 = A6 ÷ A7, AR = A8 ÷ AQ, ETC.)

2106

2107

A6 O0 A6 A7 00 AT A6

= 0.0 2106 : A6 : 0,0 2107 = A7 = A6

A~. =

H:78,750tZ4 + H(M) M=91~7~0~14 ÷ HDI(M} ÷ A7

0,0

DO 210R M=104~750,14 2lOB

A8

=

A8

÷

H(M)

A9 00 ;)109 A ¢) A8

2110

;)111

: 0,0 2109 M = 1 1 7 , 7 5 0 , 1 4 = A9 ÷ H O I ( M ) = AR * A9 A|O = 0 . 0 DO 2110 M = 1 3 0 , 7 5 0 , 1 4 AIO= AIO+ H(M) A l l = 0.0 00 2 1 1 1 M = 1 2 c J , 7 5 0 , 1 4 All = A11 + HOI(M) AIO

2112

2113

=

AIO

+

Al1

A12 = 0 , 0 DO 2 1 1 2 M = I 2 8 t 7 5 0 ~ I 4 A12 = A12 * H(M) A13 = 0o0 DO 2113 M = 1 4 1 , 7 5 0 ~ 1 4 AI3 = AI3 ÷ HDI(M) A12 = AI2 * AI3

A14 = 0.0 qO 2114 M=154t750,14 2114 AI4 = A14 + H(M) AI~ = 0 ° 0 00 2115 M=167,750,14 2115

2116

2117

AI5 = AI5 + HOI(M) AI~ = A]4 ÷ AI5 A16 = 0 . 0 DO 2116 M = 1 6 6 4 7 5 0 , 1 4 A16 = A I 6 * H(M) AI7 = 0.0 DO 2117 M=179.750~14 A17 = A17 + H O I ( M ) A I 6 = A16 + A17

A]~ = 0.0 DO 2118 M = | 7 R , 7 5 0 , 1 4 2118

A1R = A18 + H(M) Alq = 0.0 DO 2 ] l q M : 1 9 1 , 7 5 0 , 1 4

517

~)

D 3239

TABLE 2 2119 C C C C

Continued

Alg = Alg + HDI(M) Aln = Al8÷ Alg CORRECT TH~ PEAK SUMS FOR THE PRESENCE OF IRRELEVANT IONS AT MASSES 175,176,IR9,1o0,200,21~ CO1175 =HDI(I~I)-(HDI(I61)-HDI(?03})/3.O IF(HOI(I75).GE.CDII75) GO TO I 0 ~ 6 CDII?S = MOI(175)

C C C C

ABnVE STATFMENTS CORRECT HDI(175) NEXT STATEMENTS CORRECT H(176) 1046

C C C 1048

C C C

CHIT6 = H(I62)-(H(162)-H(204))/3.0 Ir(H(176).GE.CHI76)GO TO 1048 CH176 = H(176) NEXT STATEMENTS CORRECT HDI(189) CDII89 = COIl75 - (CDIITS-HOI(203))/2.0 IF(HDI(IB9).GE.COIIR9)GO TO 104q CDI1@9 = HnI(IR9)

NEXT STATEMENTS CORRECT H ( 1 9 0 ) 1049

CHIgO = C H | T 6 - ( C H 1 7 6 - H ( ? 0 4 ) ) / 2 . 0 IF(H(I90).GE.CHlOO) GO TO 2 1 0 I CH]90 = H ( ] g O )

C NEXT STATEMENTS CORRECT H ( 2 0 0 ) C C 2101 CH200 = ( H ( 1 8 6 ) * H ( ? I 4 ) ) / 2 . 0 I F ( H ( 2 O O ] . G E o C H 2 0 0 ) GO TO ?|OP CH200 = H(~O0) C NEXT STATEMENTS CORRECT H D I ( 2 1 3 ) C C 2102 CDI213 = ( H ~ I ( I O g ) * H D I ( ? 2 ? ) ) / 2 . O IF(HDI(213).GE.CDI213) GO TO 2103 COl213 = H D I ( 2 ] 3 ) C NEXT STATEMENTS CORRECT THE A 6 t A 8 o E T C . SUMS C C 2103 A6 =A6-(HOI(175)*HDI(IB9) +H(]?6)+H(IO0)) I *CDIITS

*CDIIR9÷

CHI?6*

CHI90

AlO= AIO-(H(?OO)*HDI(213))*CH2OO*CDI213 REDEFINE A~,A~,ETC. AS SUBSCRIPTED VARIARLE AND MULTIPLY BY THE AROMATICS INVERSE A I N ( I t J ) RA(1) = A6 RA(2) = A8 qa(3)

=AlO

BA(4) = AIP ~ A ( S ) = A14 BA(6) = A I R BA(7) = A I ~ O0 2125 J = 1 , 7 ~q(J)=O°O 00 2124 I = 1 , 7

2124 2125 CONTINUE ~0 E127 J = l , ? IF(BB(J))El?S,PI27,2127 2126 ~R(J)=O°O 2127 CONTINUE AA6 = 8 R [ 1 ) AAA

=

~R(2)

AAIO = B B ( 3 ) ~ A I 2 = 88(4) AA]4 = B8(~) AA]6 = BB(~) AAI8 = RB(7) SUMAA = 0*0 DO 212B J = l , 7

518

~

D 3239

TABLE 2 2128 C C C C C C

SUMAA =

Continued

SUMAA*PR(J)

VALUES OF AA6,AA8~ETC. ARE DIVISIONS CALCULATED FOR NOMINAL Z=-6~ -~,ETC. SUMAA IS SUM OF THE AA VALUES AND REPRESENTS THE TOTAL DIVISIONS OF AROMATICS CALCULATED. THE FOLLOWING STATEMENTS RESOLVE OVERLAPPING TYPES IN Z = -6~ A7 : AT-HDI(17S)-HDI(IRQ)+CDII7S÷CDII89 HOI(17S)=CnII?5 HOI(IBg)=CDII89 DO 2 1 3 0 M = 1 0 5 , 7 5 0 , 1 4 IF(HDI(M))~130~2131~2130 2 1 3 0 CONTINUE 2 1 3 1 MM : M - 1 4 SLOPE : ( ( ( O . 7 ~ * H D I ( I O S ) ) * * O . 5 ) - ( H D I ( M ~ ) ) * * 0 . 5 ) / I (90.7I-(IO00.O/rLOAT(MM))**2) B = (O.72*HOI(IOS))**O.5-QO.7]*SLOPE DO 2133 M=I47.MM~I4 ~EALM = M +B 2 1 3 3 SR(M) : S L O P E * ( I O O O , O / R E A L M ) * * 2

C C C C

ABOVE IS FO~ Z = - 6 AND STORES SQUARE ROOTS OF ALKYL BENZENE OEAK HEIGHTS IN ARRAY 5R(I).R~LOW IS rOB Z = -B

DO 213~ M=PI5.7SO~14 IF(HDI(M))?134.2135~2134 2 1 3 4 CONTINUE 2 1 3 5 MN = M-14 SLOPF = ( ( ( O . 6 6 * H D I ( 1 7 3 } ) * * O . S ) - ( H O I ( M N ) ) * * O . 5 ) / (34.12 -(IO00.O/CLOAT(MN))**2) B : (0.66*HDI(173))**O.5-34.I2*SLOPE DO 2 1 3 6 M = ? I S ~ M N ~ I 4 REALM : M 2136 SP(M) = SLOPE*(IOOO.O/REAL~)**? +@ C C C

BELOW IS FnR Z = - I 0

A l l = A l l - HDI(PI3)*COI213 H01(213) = C01213 DO 2137 M=?41tTSO.14 Ir(HDI(M))P]37,2138,2137 2 1 3 7 CONTINUE 2 1 3 8 MO = M - 1 4 SLOPE = ( ( H ~ I ( I R S ) ) * * O , S - ( H ~ I ( M O ) ) ~ O , ~ ) / 1 (2g,22-(lOOO,O/~LOAT(MO))**2) B= H D I ( 1 8 5 ) * * O , 5 - 2g,~?*SLOPE DO 2 1 3 9 M = ? 4 1 ~ M O ~ I 4 REALM = M 2 1 3 9 SR(M) : SLhPE*(IOOO.O/REAL~)**~÷B C BELOW I S FOR Z = - 1 2 C C 00 2140 M:]97.750~14 IF(HDI(M))?I40,2141,2140 2 1 4 0 CONTINUE 2 1 4 1 qP = M-14 SLOPE = ( ( ( O . 2 5 * H D I ( I B 3 ) ) * * O . 5 ) - ( H O I ( M P ) ) * * O . 5 ) / l (29.8&-(InOO.O/FLOAT(MP))**2) B = (0,25"WDI(183))**0.5 - 29,S&*SLOPE

DO 2 1 4 2 M=]97~MP~14 2142 C C C

REALM = M SR(M) = SLOOE*(IOOO.O/REALM)**2+B BELOW IS FnR Z = -14

00 2143 M=765,750,14 IF(HOI(M))?I43.2144,2143 2 1 4 3 CONTINUE 2 1 4 4 MQ = M-14 SLOPE = ( ( ( O . 6 4 * H D I ( 2 5 1 } ) * * O . 5 ) - ( H O I ( M Q ) ) * * O . 5 ) / 1 (IS.RT-(INOO.O/FLOAT(MQ))**2) B : ( 0 . 6 4 " H D I ( 2 5 1 ) ) * * 0 . 5 - 15.RT*SLOPE

519

~ TABLE

2145 C C C

D 3239 2

Continued

DO 2145 M=P65,MO~I4 REALM = M SR(M) = SLO~E*(IOOO.O/~EALM)**2÷B RELOW IS FOR Z = - 1 6

O0 2 1 4 6 M = 7 9 1 ~ 7 5 0 , 1 4 IF(HDI(M))PI46,2147,2146 2 1 A 6 CONTINUE 2 1 4 7 MO = M - 1 4 SLOPE = ( ( ( O . 7 * H D I ( 2 7 7 ) ) * * O . 5 ) - ( H O I ( M R ) ) * * O . 5 ) / 1 (I3.03-(IO00.O/rLOAT(MR))**2) B = (O.7~HOI(277))**O.5-I3.03*SLOPE DO 2 1 4 ~ M = ~ 9 1 ) M R ) 1 4 REaL M = H 2148 S ~ { M ) = S L O P E ~ i l O O O . O / R E A L M ) t * 2 ÷ ~

C C C

qELOW IS FOR Z = -18

O0 2 1 4 9 M = ~ 7 . 7 5 0 ~ 1 4 IF(HDI(M) )214a,~150,2I~9 2 1 4 0 CONTINUE 2150 ~S = M-14 SLOPE = ( ( ( 0 . S A * H D I ( 2 3 3 ) ) * * 0 , 5 ) - ( H O I ( W S ) ) * * 0 , 5 ) / 1 (18.42-(IO00.O/FLOAT(MS))**2) R = (O.58*MOI(P33))**O.5-18.42*SLOPE 00 2 1 5 1 M = P ~ T ~ M S ~ 1 4 REALM = M 2151 5~(M) = SLOPE*(IOOO.O/~EALM)**?+~ C THE SQUARE ROOT ARRAY HAS qEEN CALCUL~TEO. FOR CERTAIN SPECTRa IT C MAY BE PO~SIRLE TO GET SLOPE AN~ INTERCEPT VALUES I N REGIONS OF C ZERO PEAK H E I G H T . I F T H I S OCCURSt ERRORS HIGHT BE ENTERED I N THE C SR &RRAY. THE FOLLOWING SETS ~R TO ZErO AT MASSES WHERE H D I = O . O C C 00 2153 I=12,750 Ir(HOI(I)) 2152,2152~2153 2152 SR(I) = 0.0 2 1 5 3 CONTINUE C THE SR ARRAY IS SQUARED TO GIVE UNCOPQECTED PEAK HEIGHTS OF THE C NOMINAL Z TYPES C C DO 2 1 5 4 I = I 2 , 7 ~ 0 =(S~(I)**2) 2154 SP(I) C CORRECT CERTAIN VALUES IN S R ( I ) FOR NONLINEARITY OF Sq RT RELATION C C SR{147) = SR(I~T)Ol.a~ SP(197) = SR(lq7)°3,10 SP(211) = SR(211)'2,52 S~(225) = 5P(~25)'2,07 S~(23q) = ~R(23q)Ql,83 SR(253) = SR(253)*].59 SR(267} = SR(267)*l.39 SR(2R[) = ~R(281)*1.28 SR(295) = ~R(2QG)*1oP6 55(309) = RR(309)*1.14 Sq(323) = $R(323)'1°06 S0(265) = SR(2~5)~].42 SP(279) = ~P(~Tg)*I.~4 ~Q(293) = ~R(203)*1.]2 SR(307) = 59(307)*1.06 SR(291} = SP(291)*1°24 SR(305) = SR(305)*1.15 SR(319) = SR(319)'1,07 SP(333} = ~R(333)'1.06 SR(347) = ~R(347)*1.05 5R(361) = SR(361)*I,03 SP(247} = ¢R(~47}*1.61 S~(2&I) = SR(P~I)*I.50 5P(275) = ~R(275)*1.44 SR(289) = ~R(289)*1o37 SR(303) = ~R(303)*1.28

520

~

D 3239 Continued

TABLE 2

SR(317) SR(331) SP(3~S) SQ(359) SR(373) SP(387)

2155 2156 C C C

= = = = = =

SP(317)*1o28 qR(331)~1.21 SR(345)~1,10 ~Q(359)~I.09 ~R(373)#I°07 SR(387)~I.05

IT IS NECESSARY THAT NO VALUE SR(~) EXCEEDS THE CORRESPONDING VALUE HDI(M) O0 2 1 5 6 M = 1 2 t 7 5 0 IF(SR(M)-HnI(~))~]56,2156,~lSS SR(M) = HDI(M) CONTINUE CALCULATE PORTIONS OF A7 DUE TO A6AtA]OS.A20A AND OTHER TYPES

2157 2158

A6A = 0 . 0 DO 2 1 5 7 M = q l . 1 3 3 , 1 4 A6A = A 6 A + H O I ( M ) DO 2 1 5 8 M = 1 4 7 ~ M M , l ~ A6A = A 6 A ~ R ( M ) AIOS = 0.0 DO 2 1 5 9 H=147o189,14

2]50

2160 2161 C C C

AIOS = AlO5 + HOT(M) AIOS = A105/.75 A20A = A 7 - A 6 A - A I O ~ IV(A20A)2160,2161t2]61 A20A = 0 . 0 AlflS = A7-A6A CONTINUE

SR(M)

CALCULATE DIVISIONS OF A6AeAIOS,AND A20A TRASH = ( A 6 - A A 6 ~ . 5 5 7 9 ) ~ ( A 7 / A 6 ) Ir(TRASH,LT,O,O)TRASH = 0,0 A7 = A7 - TRASH IF(AT.LE.O.O)A7 = 1.0 A6A = A6A - TRASH IF(A6A.LT.O.O)A6A = 0 o 0 Ir(A~A.EQ.O.O)A7=AIOS*A20A A6a = ( A 6 A / A T ) ~ A A 6 A1flS = (AIOS/AT)~AA6 A20A = (A2OA/AT)~AA6

CALCULATE PORTIONS OF A9 DUE TO ABA~A?~A,AND OTHEQ TYPES

2162 2163

2164

ARA = 0°0 DO 2 1 6 2 M = 1 1 7 , 2 0 1 , 1 4 ASA = A8A÷~DI(M) DO 2 1 6 3 M = ~ I S , M N ~ ] 4 ASA = ASA÷FR(M) A22A = 0 . 0 DO 2 1 6 4 M = ~ 1 5 t 2 5 7 , 1 4 A2?A = A22A • HDI(H) A~A = A22A/,75 A3~A = A 9 - A R A - A 2 ~ A

-

SR(~)

Ir(A36A)2165,2166,216~

C C C

2165

A36A

2166

A2~A : A g - A S A CONTINUE

=

0,0

CALCULATE nIVISIONS

OF ABA,A2~AtAND OTHER TYPES

TRASH : (AR-AAR~.Aqq7)e(Aq/AR) Ir(TRASH.LT.O.O)TRASH = 0 , 0 AQ = Aq - TRASH IF(A9.LE.O°O)AQ : I . 0 ARA : A~A - TRASH I~(ASAeLTe~eO)A8A = 0.0 IF(ASA.EQ,O,O)Ag=A2?A~A36A ARA = ( A S A / A g ) ~ A A ~ A22A = (A2~A/Ag)~AAR A36A = ( A 3 A A / A q ) ~ A A 8

521

~

D 3239

TABLE 2

CALCULATE PORTIONS OF A l l

Continued

DUE TO AIOA,A24AtAND OTHER TYPES

AIOA = 0.0 O0 2167 H=129.~27,14 2167 AIOA = AIOA*HDI(M) DO 2 1 6 8 M=~41,MO,I4 2168 AI~A = AIOA*SR(~) A~&A = 0 , 0 DO 2 1 6 9 M f P 4 1 , ~ 8 3 , 1 ~ SR(M) 2 1 6 9 A2~A = A24A * H O I ( M ) A24A = A 2 ~ A / , 7 5 A38A = A I I - A I O A - A 2 ~ A IF(A38A)2170,2171,2171 2170 A3RA = 0 , 0 A2~A = A l l - A I O A 2171 CONTINUE C CALCULATE DIVISIONS OF AIOA.A24A,AND OTHER TYPES C C TRASH = ( A 1 O - A A I O * . 4 4 3 S ) * ( A l l / A ] O ) Ir(TRASH.LT.O.~)TRASH = 0.0 A l l = A l l - TRASH I F ( ~ I I . L E . O . O ) A I I = 1.0 AIOA = AIOA - TRASH IF(AIOA.LT,O,O)AIOA = 0.0 I~(AIOA.EO.O.O)AII=A24A*A3~A AIOA = ( A I O A / A I ] ) * A A ] O A24A = ( A 2 4 A / A 1 ] ) * A A l O A3AA = ( A 3 ~ A / A I I ) * A A I O -

CALCULATE PORTIONS Or AI3 DUE TO AI2A,AI6StAND

2172 2173

2174

2175 2176 C C C

OTHER TYPES

AI2A = 0 . 0 00 2172 M = 1 4 1 . 1 8 3 , 1 ~ A I 2 A = AX2A÷HOI(M) DO 2 1 7 3 M f ] 9 7 , M P t I 4 AI~A = AI2A*SR(M) A I 6 S = 0.0 DO 2 1 7 ~ M = I Q T , p 2 5 , 1 4 A I ~ S = Al6~ ÷ H O I ( M ) - SR(w) AI6S = A16~/o6~5 A26A = AI3-A12A-AI6S IF(A26A)2175,2176,2]76 A 2 6 A = 0.0 A I 6 S = AI3-AI2A CONTINUE CALCULATE nIVISIONS

Or AI2A,A16StA26A

T~ASH = ( A I 2 - A A I ? * . S l g ? ) * ( A I 3 / A 1 2 ) IF(TRASH.LT.O.o)TRASH = 0 . 0 A13 = AI3 - TQASH I r ( A I 3 . L E . O . O ) A I 3 = 1.0 AI2A = AI2A - TRASH I r ( A I 2 A . L T . O . O ) A ] 2 A = 0.0 IF(AI2A.EQ.O.O)AI3=A16~*A26A AI2A : (AI~A/A13)*AA12 A16S = ( A I 6 S / A I 3 ) O A A ] 2 A~6A = ( A 2 6 A / A 1 3 ) e A A ] 2 CALCULATE PORTION OF AIS DUE TO AI4AtA~BAtAND OTHER TYPES

2177 2178

A I 4 A = 0.0 DO 2 1 7 7 M = 1 6 7 , ~ 5 1 . 1 4 AI4A = AI~A+HOT(M) DO 2 1 7 8 M = ? 6 5 , M O , 1 4 AI4A = AI4A*SR(M) A2~A

2179

=

0,0

DO 2 1 7 9 M = ~ 6 5 , 3 0 7 , 1 4 A?~A = A2~A * H D I ( M ) A28A = A 2 8 A / , 7 5 A4~A = A 1 5 - A 1 4 A - A 2 8 A

SR(M)

522

I{~) V 3239 TABLE 2

2180 21B1 C C

Continued

IF(A42A)21AO*2181,2181 A42A = 0,0 A2RA = A 1 s - A I ~ A CONTINUE

CALCULATE DIVISIONS OF AI4A,A2AA.ANO OTHER TYPES

C TRASH = ( A I 4 - A A I ~ * . 5 0 7 5 ) ~ ( A l S / A I ~ ) Ir(TRASH.LT.O.O)TRASH = 0.0 AIS = A15 - TRASH I F ( A I 5 . L E . O . O ) A I 5 = 1.0 AI4A = AI4A - TRASH I F ( A I 4 A . L T . O . O ) A 1 4 A = 0o0 IF(AI4A°EQ.O.O)AIS=A28A+A42A AI4A = (Al~A/AlS)~AA14

C C C

A2AA

=

(A2~A/A15)*AA|4

A42A

=

(A4~A/AIS)~AA14

CALCULATE PORTIONS OF AI7 DUE TO A16AtA30A,ANO OTHER TYPES

A16A = 0,0 DO 2 1 8 2 M = 1 7 9 , 2 7 7 t 1 4 2 1 8 2 AI6A = AIAA+HOI(M) DO 2 1 8 3 M = ~ g l , M R , 1 4 2183 AIAA = A16A÷SR(M) A30A = 0,0 00 2 1 8 4 ~ = 2 9 1 , 3 3 3 , 1 4 2 1 8 4 A30A = A30A + HDI(M) - SR(~) A3flA = A30A/.75 A44A = AIT-AlAA-A30A IF(A&&A)21RSt2186t2186 2 1 8 5 A 4 4 A = 0.0 A30A = A17-AlAA 2 1 8 6 CONTINUE C CALCULATE nIVISIONS OF AIAA,A30A~AND OTHER TYPES C C TRASH = ( A l A - A A 1 6 ~ . 4 9 1 0 ) * ( A l T / A I 6 ) IF(TRASH.LT.O.O)TRASH = 0.0 AI7 = A17 - T~ASH I r ( A 1 7 . L E . O - O ) A I 7 = 1.0 A I 6 A = A 1 6 A - TRASH IF(A16AoLT.O,O)A16A = 0.0 TF(AI6A.EQ.O°O)AI7=A30A+A4~A A16A = (AIAA/AI7)~AA16 A30A = (A3~A/A17)~AA16 A4&A = ( A 4 4 A / A I T ) ~ A A 1 6

CALCULATE PORTIONS Or A ] 9

2187 2188

2189

2190 2191 C C C

A 1 8 A = 0.0 O0 2 1 8 7 M = 1 9 1 , 2 3 3 , 1 4 A18A = A18A+HDI(M) O0 2 1 8 8 M = 2 4 7 , M S , 1 4 AIRA = A18A÷SR(M) A2~S = 0.0 DO 2 1 8 q M=p47.28q~14 A2~S = A22~ ÷ HDI(M) A~PS : A 2 ~ R / ° 7 5 A3~A = AIg-AIRA-A~?S IF(A32A)21aOt2|91121ql A3?A = 0.0 A~2S = AI9-AIAA CONTINUE

-

DUE TO A I 8 A t A 2 ~ S t A 3 2 A

SR(~)

CALCULATE DIVISIONS OF AISA.A22StAND OTHER TYPES TRASH = ( A I B - A A I R ~ . S O T 3 ) i ( A I g / A ] 8 ) Ir(TRASH.LT.O.O)TRASH = 0 , 0 Alq'= A 1 9 - TRASH IF(A|9.LE.O.O)AIq = ].0 AIRA = AISA - TRASH I F ( A | S A . L T . O . O ) A I R A = 0,0 TF(AISA.EQ.O.O)AIg=A22$÷A3~A AIRA = (Al~A/AIg)~AA18 A2~S = (A2~S/AI9)*AA18 A32A = (A3?AIAIg)~AA18

523

~

D 3239

TABLE 2

Continued

THIS COMPLETES CALCULATION OF AROMATICS BREAKDOWN VOLUME PERCENTS ARE NEXT CALCULATED V6A = ]O0.~*A6A/SUMAA VI~ = IO0.O*AIOS/SUMAA V 2 0 A = IO0.O*A~OA/SUMAA

V~A = IO0.O~ABA/SUMAA V22A : IO0.O*A2?A/SUMAA V 3 6 A : IO0.OiA36A/SUMAA V I O A = IO0.O*AIOA/SUMAA V2~A = IO0.O*A?AA/SUMAA V3RA = IO0.O*A38A/SUMAA VI2A = IO0.O*AI2A/SUMAA VI6S = IO0,O*AI6S/SUMAA V~6A = IO0°O*A?6A/SUMAA VI6A = IO0.O*AI4A/SUMAA V2BA = |O0.O*A28A/SUMAA V~A = IO0.O*AA2A/SUMAA VI6A = IO0,O*AI6A/SUMAA V30A = IO0.O*A3OA/SUMAA V~A = IO0°O*A~A/SUMAA VIBA = IO0.O*AIBA/SUMAA V2~S = |O0°O*A?2S/SUMAA V32A = IO0,O*A32A/SUMAA AMONO = A6A÷ARA~AlOA VMONO = V6A÷V~A*VlOA ADI = Al2A*Al4A÷AIGA VOI = VI2A*VI~A÷VI6A ATRI = AIRA*A20A VTRI = VISA-V20A ATET~A = A~2A~A2~A VTETRA = V ~ A ÷ V 2 ~ A APENTA = A ? ~ A * A 3 0 A VPENTA = V ~ R A + V 3 0 A ATMIO = AIOS~A]6S*A~S VTHIO = VIOS÷VI6S÷VP2S AUNID = A 3 6 A * A 3 8 A ÷ A 2 6 A ÷ A ~ A + A ~ A A + A 3 2 A VUNIO : V36A÷V38A+V~6A+V~2A+VA~A+V32A

WRITE WRITE WRITE WRITE WRITE W~ITE WRITE WRITE WPITE |

(6~2~00)

(6,2SOI)(TITLE(I)~I=It20) (6t2SO2)AMONO,VMONO,A6A~V6AtASA,VRA,AIOA,VIoA (6~2S03)ADI,VOI,AI2A,VI2A,AI4AtVI4AtAI6A,VI6A (6,2~04)ATPI,VTRI,AIBA,VIRAtA~OA,V?OA (6~2505)ATETRA,VTETRAtA2?A,V~2A,A24A~V2~A (6,2S06)~PENTA,VPENTAtA2~A~V28AtA30AtV30A (6t2~O7)ATHIOtVTMIO,AIOS,VIOS,AI6S,V16S,A22~,V2~S (6t2~OS)AUNIDtVUNID~A36A,V36AtA38A,V3~AtA26&~V26A~A~2A,V42At

A~AtV44A,A32AtV32A

2500 FORMAT (IHI 9X,44HMASS SPECTRAL ANALYSIS OF AROMATIc FRACTIONS) 2501

FORMAT

(IHO,2OA41/3RX,PTHCALCo I O N SUMS

VOLUME PCT)

(]HO,SX.13HMONOAROMATICSt24X,F7°O~6XtF7°I/IOXtI3HALKYL~ENZE INES~ISXtF7.0,6X,FT,I/IOX,ITHNAPHTHENEQENZENEStIIX,F7.0,6X,F7.I/

2502 FOQMAT

2IOX,IgHDINAPHTHENERENZENES,gX,FT.O,6XtF7.I) FORMAT (lHO,SX,IIHDIAROMATICS,26X,F7.O,~X,FT°I/IOX~12HNAPHTHALENES I,I~XtF7,O,~XtFT.I/IOX,pBHACENA~HTHENES, OIBENZOFURANS,F7,0,6X.FT.I 2/IOX,gHFLUDRENFStIgX,E7oO,6XtF7°I) 2506 FORMAT (IHOt8X,12HTRIAPOMATICS,~SX,F7.0,GX,FT°I/IOX,13HPHENANTHREN IES,ISX,FT.O,GX,F7.I/IOX~22HNARHTHENEPHENANTHRENES,6X,FT.O,6XtF7.I) 2505 FORMAT (IHO,SX,14HTETRAARO~ATICS,23XtF?,O~6XtF?.I/IOX,THPYRENES,21 IX,rT°O,6X,F7°I/IOX,9HCHRYSENES,I9X,FT.O,GX,F7.I) 2506 FORMAT (IHO,RX,14MPENTAAROMATICS~?3XtFT.O,6XtFT°I/IOX,gHPERYLENES, llgX,F7.0,6X,F7.1/IOX,17HOIBENZANTHRACENEStliX,FT.O,6XtFT,I) 2507 FORMAT (IHO,BX,IgHTHIOPMENO AROMATICSt]BX~FT.O,6X,FT.I/IOX,ISHRENZ IOTHIOPHENES,13XtFT°Ot6X,F7,I/IOX~I7HOIRENZOTHIOPHENES,IIXtF?.O~6X, 2FT.I/IOXt2?HNAPHTHOBENZOTHIOPHENES,6XtF7.0,6X,F7°I) 2508 FORMAT (IHfl,SX,22HUNIOENTIFIED AROMATICS,lSXtFT.O,6XtFT.I/IOXt37HC ILASS I INCL WITH NAPH PHENANTMRENES/IOX,BHCLASS IIt2OXtF?.Ot6X,F7 2.I/IOXtgHCLASS III,19XFT.O,6Xt~7.I/IOXtBMCLASS IV,2OX,FT,O,6X,F?,I 3/lnX,THCLASS V,21X,FT.Ot6X,FT.I/IOXtBHCLASS VI,?Ox,FT°OtGX,F7.1/IO 4X,gHCLASS V I I , I g X , F T . O , 6 X , r T , I ) RETURN END 2503

524

~) D 3239 TABLE 3 MASS HT

MASS HT 78 126 86 46 94 93 102 92 11o 68

79 87 95 103 111

118 126 134 142 1S0

270 13# 2~5 297 83

158 166 174 182 190

PC-69-378 Test Spectrum for Gas Oil Aromatics Analysis MASS HT

332 77 ~80 127 143

M A S ~ HT

M A q S HT

H A S ~ HT

M A ~ S HT

MASS HT

80 98 ~P 72 96 108 104 174 112 ~5

81 89 97 |05 113

610 l~O 30] 98~ 13~

82 128 90 35 98 62 106 387 114 117

83 91 99 ]07 115

532 694 53 ]87 402

84 76 92 210 I00 54 108 107 116 ] 9 4

85 93 lO1 109 117

181 216 158 264 40~

1191045 127 175 135 112 1#3 496 151 140

120 128 136 144 1~2

389 407 47 2R9 247

121 129 137 145 153

16# 482 98 739 229

172 70 ] 3 0 287 138 78 I#6 212 154 163

123 131 139 I#7 15~

152 659 ]46 289 486

1~4 48 132 272 140 72 148 102 156 p 6 4

125 133 141 149 157

I04 66~ 406 94 438

226 2O4 106 160 143

159 167 175 183 191

53~ 268 ]25 280 297

160 168 ]76 184 ]92

144 180 1P9 134 262

161 159 177 185 193

161 43# 10# ?26 380

162 70 170 209 178 334 1~6 98 194 200

163 171 179 187 195

119 318 #14 218 318

16# 76 172 140 180 204 la~ 96 19~ 132

165 173 181 189 197

477 316 312 306 191

198 98 206 25~ 214 03 222 133 230 206

I~9 207 215 223 231

179 316 374 169 244

200 208 216 224 23?

112 171 213 124 171

201 209 217 225 233

158 ?~0 225 ]5# ]97

~02 ~I0 218 226 234

300 117 156 184 162

203 211 ?19 227 235

253 168 269 181 172

204 212 220 228 236

144 90 216 2OO 112

205 213 221 229 237

307 198 238 320 150

238 246 2~4 262 270

113 ]67 124 121 1~

239 247 255 263 271

257 153 178 145 144

240 248 256 264 272

136 130 172 I~4 144

241 24q 257 265 273

189 ]3# ]90 162 11#

24? 250 258 ~66 274

174 132 173 ]56 1#2

243 25] 259 267 275

251 118 156 153 105

244 252 260 268 276

196 192 152 128 149

~4~ 253 261 269 277

214 ~00 131 156 115

278 286 294 302 310

130 127 134 127 120

279 136 287 97 295 115 303 93 311 92

280 288 296 304 312

143 124 127 Ill 116

2B1 ] 3 3 289 ] I # 297 108 305 85 313 91

282 ?90 298 306 314

132 123 129 122 ]20

283 127 291 94 299 95 307 93 315 78

284 292 300 308 316

133 125 130 123 116

285 11~ 293 112 301 82 309 95 317 77

318 326 334 342 350

106 118 109 II0 108

319 327 335 343 351

78 78 78 62 69

320 328 336 344 352

116 llS 108 107 104

321 329 337 345 353

8] 69 73 61 67

327 330 338 3#6 354

llS 112 108 98 100

323 331 339 347 359

80 68 75 61 57

324 332 340 348 356

118 101 108 102 104

325 333 341 349 357

82 69 67 75 56

358 102 366 104 374 84 382 88 390 aO

359 367 375 383 391

54 63, 47 49 47

360 368 376 384 392

o2 96 ~8 91 84

361 369 377 385 393

54 56 54 #6 #8

362 370 378 386 394

96 98 90 87 84

363 37] 379 387 395

'69 50 55 44 48

364 102 372 95 380 90 3q8 76 396 80

365 373 381 389 397

73 49 54 43 45

398 406 414 422 430

84 76 76 %~ ~4

300 407 415 423 431

42 42 38 38 30

400 408 416 424 432

Rl 75 60 ~4 56

401 409 417 425 431

#1 #2 34 36 3~

#0 ~ #10 #18 426 #36

67 72 53 69 59

403 411 419 #27 435

38 40 34 34 33

404 412 4~0 428 436

70 77 66 66 59

405 413 421 429 437

41 38 38 33 34

438 446 454 462 470

57 ~9 S# 46 44

439 447 455 463 471

32 28 27 26 23

440 448 456 464 472

61 53 SO 47 36

441 449 #57 465 473

30 30 26 26 21

#47 #50 458 #&6 474

58 54 41 45 38

4#3 451 #59 467 475

30 30 23 25 22

44# 452 460 468 476

47 52 64 48 40

445 453 461 469 477

27 28 25 24 22

478 486 494 502 510

41 31 34 28 30

479 487 495 503 511

23 17 lfl 15 1~

480 4AR 496 504 512

40 33 35 30 78

#81 #89 497 505 513

22 19 18 17 18

#82 #90 498 506 514

40 35 33 30 27

483 49] 490 507 515

21 19 17 18 13

484 492 500 508 516

38 35 26 29 24

485 493 SOl 509 517

20 F0 15 17 14

518 526 534 542 550

25 24 ~1 1S 16

519 527 535 543 551

14 13 12 9 9

520 528 536 544 552

26 18 20 16 16

521 529 537 ~45 553

1# II 1] 11 9

5~2 530 538 546 554

24 20 20 18 14

523 53] 539 547 55~

14 12 II I0 8

524 532 S#o 548 5~6

24 20 18 18 II

525 533 541 549 557

14 12 II 10 7

558

566 5 7# 582 590

11 12 I0 8 8

559 567 575 583 591

R O 6 S 6

~60 568 576 584 K92

13 11 lO 7 8

561 569 577 585 593

8 8 6 ~ #

562 570 578 586 ~94

14 9 9 7 7

563 571 570 587 59~

8 6 6 S 4

564 572 580 5~ 596

12 10 9 7 6

565 573 581 ~89 597

a 8

5 98 6 06 614 622

5 5 4 4

599 607 615 624

4 3 4 3

600 &08 616 626

6 5 4 3

601 609 617 628

# 3 3 3

602 610 618 630

8 4 4 3

603 61] 619 632

4 604 3 612 3 620 3099999

6 4 4

605 613 621

525

5 4 .

3 3

o a2a9 l 1.1.2 Reproducibility--The difference between two single and independent results, obtained by different operators working in different laboratories on identical test material, would in the long run, in the normal and correct operation of the test method, exceed the values shown in Table 5 only in one case in twenty.

conditions employed in this empirical method, and a statement of bias is therefore not appropriate. 12. Keywords

12. l aromatic; gas off; mass spectrometry; petroleum

NOTE 6--1f samples are analyzed that differ appreciably in composition from the sample used for the interlaboratory study, this precision statement may not apply.

TABLE 5

11.2 Bias--The quantities determined are defined by the TABLE 4 M a s s Spectral A n a l y s i s o f A r o m a t i c Fractions PC-69-378 Test Spectrum for Gas Oil Aromatics Analysis Calc. Ion Sums Volume %

90.

Monoaromatics: Alkylbenzenes Naphthenebenzenes Dinaphthenebenzenes Diaromatics: Naphthalenes Acenaphthenes. dibenzofurans Fluorenes Triaromatics: Phenanthrenes Naphthenephenanthrenes Tetraaromatics: Pyrenes Chrysenes Pentaaromatics: Perylenes Dibenzanthracenes ThiophenoAromatics: Benzothiophenes Dibenzothiophenes Naphthobenzothiophenes Unidentified Aromatics: Class I incl with Naphthenephenanthrenes Class II Class III Class IV Class V Class VI Class VII

28498. 9703. 9017. 9778. 19158.

26.2

4774. 6576.

6.5 9.0

7809.

10.7 9625.

6070.

8.3 5.4 2.9

1658. 1293. 366

2.3 1.8 05

1872. 565. 988. 339.

2.6 0.8 1.3 0.5

6322.

614. 838. 3431. 546. 281. 612.

¢rr

oR

r

R

13.7 13.3 13.7

0.3 0.1 0.2

1.0 1.1 0.4

1.2 0.5 0.9

3.0 3.3 1.1

Naphthalenes Acenaphthenes/dibenzofurans Fluorens

6.7 9.0 10.7

0.2 0.1 0.1

0.8 0.2 0.2

0.9 0.5 0.3

2.3 0.5 0.6

Phenanthrenes Naphthenephenanthrenes

8.6 4.5

0.1 0.2

0.3 0.4

0.2 0.7

1.0 1.2

Pyrenes Chrysenes

5.7 2.8

0.1 0.2

0.5 0.4

0.3 0.5

1.6 1.1

Perylenes Dibenzanthracenes

1.7 0.4

0.1 0.1

0.2 0.1

0.3 0.2

0.6 0.4

Benzothiophenes Dibenzothiophenes Naphthabenzothiophenas

1.0 1.5 0.5

0.2 0.1 0.1

0.4 0.3 0.3

0.8 0.3 0.3

1.1 0.8 1.0

Class II Unidentified Class III Unidentified Class IV Unidentified Class V Unidentified Class VI Unidentified Class VII Unidentified

0.4 0.6 4.1 0.5 0.2 0.4

0.1 0.1 0.2 0.1 0.1 0.2

0.4 0.4 0.5 0.3 0.1 0.2

0.3 0.4 0.6 0.5 0.3 0.5

1.1 1.2 1.6 0.8 0.4 0.7

13.1 8.4 4.7

3980. 2090.

Vol ~ Alkylbenzenes Naphthenebenzenes Dinaphthenebenzenes

38.9 13.3 12.3 13.4

6156. 3470.

Precision Summary Based on Cooperative Data

~, = repeatability standard deviation ~ = reproduobility standard deviation r = repeatability R = reproducibility

8.6

0.8 1.1 4.7 0.7 0.4 0.8

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards. 1916 Race St., Philadelphia, PA 19103.

526

(~t)

Designation: D 3241 - 97

..

Designation: 323/89

i,~.ur,

An Amedean National Standard

Ilk m i aiH [[IM

Standard Test Method for Thermal Oxidation Stability of Aviation Turbine Fuels (JFTOT Procedure) 1 This standard is issued under the fixed designation D 3241; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epeflon (0 indicates an editorial change since the last revision or reapproval.

This test method has been approved by the sponsoring committee and accepted by the cooperating organizations in accordance with established procedures. This standard has been approved for use by agencies of the Department of Defense. Consult the DoD Index of Specifications and Standards for the specific year of issue which has been adopted by the Department of Defense.

Color Standard for Tube Deposit Rating5

1. Scope 1.1 This test method covers the procedure for rating the tendencies of gas turbine fuels to deposit decomposition products within the fuel system. 1.2 The values stated in SI units are to be regarded as the standard. The inch-pound values given in parentheses are for information only. The differential pressure values in mm Hg are defined only in terms of this test method.

1.3 This standard does not purport to address all of the safety concerns, if any,, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements, see Notes 1, 2, 3, 7 and Annex A2.

3. Terminology 3.1 Definitions of Terms Specific to This Standard: 3.1.1 deposits--oxidative products laid down on the test area of the heater tube or caught in the test filter, or both. 3.1.1.1 DiscussionDFuel deposits will tend to predominate at the hottest portion of the heater tube which is between the 30 mm and 50 mm position. 3.1.2 heater tubeDan aluminum coupon controlled at elevated temperature, over which the test fuel is pumped. 3.1.2.1 Discussion--The tube is resistively heated and controlled in temperature by a thermocouple positioned inside. The critical test area is the thinner portion, 60 mm in length, between the shoulders of the tube. Fuel inlet to the tube is at the 0 mm position, and fuel exit is at 60 mm. 3.2 Abbreviation: 3.2.1 AP--differential pressure.

2. Referenced Documents

4. Summary of Test Method 4.1 This test method for measuring the high temperature stability of gas turbine fuels uses the Jet Fuel Thermal Oxidation Tester OF'rOT) that subjects the test fuel to conditions that can be related to those occurring in gas turbine engine fuel systems. The fuel is pumped at a fixed volumetric flow rate through a heater after which it enters a precision stainless steel filter where fuel degradation products may become trapped. 4.1.1 The apparatus uses 450 mL of test fuel ideally during a 2.5 h test. The essential data derived are the amount of deposits on an aluminum heater tube, and the rate of plugging of a 17 Ix nominal porosity precision filter located just downstream of the heater tube.

2.1 A S T M Standards: D 1655 Specification for Aviation Turbine Fuels: D 4306 Practice for Aviation Fuel Sample Containers for Tests Affected by Trace Contaminationa E 128 Test Method for Maximum Pore Diameter and Permeability of Rigid Porous Filters for Laboratory Use4 E 177 Practice for Use of the Terms Precision and Bias in ASTM Test Methods4 E 691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test MethOd4 2.2 Adjunct:

5. Significance and Use 5.1 The test results are indicative of fuel performance during gas turbine operation and can be used to assess the level of deposits that form when liquid fuel contacts a heated surface that is at a specified temperature.

' This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.J on Aviation Fuels. Current edition approved June 10, 1997. Published October 1997. Originally published as D 3241 - 73 T. Last previous edition D 3241 - 96a. 2 Annual Book of ASTM Standards, Vo105.01. 3 Annual Book of ASTM Standards, Vo105.02. 4 Annual Book of ASTM Standards, Vol 14.02.

s Available from ASTM Headquarters. Order Adjunct No. 12-416600-00.

527

(@) D 3241 TABLE 1 JFTOT Model

User Manual

Models of JFTOT

Pressurize Pump With Principle Differential PreSsUreBy

202

202/203A

nitrogen

gear

203

202/203 A

nitrogen

gear

215

215 s

nitrogen

gear

230 240

230/240 ¢ 230/240 c

hydraulic hydraulic

syringe syringe

Hg Manometer; No Record Manometer + Graphical Record Transducer + Printed Record Transducer + Printout Transducer + Printout

TABLE 2

Cdtical Operating Charactadstics of JFTOT Instruments Item

Definition tubeqn-shell heat exchanger as illustrated in Fig. 1.

Test apparatus Test coupons Heater tube•

speciallyfabricated aluminum tube that produces controlled heated test surface; new one for each test nominal 17 ttm stainless steel mesh filter element to trap deposits; new one for each test

Test filtere Instrument parameters Sample volume

'q AvalleUtefrom ASTM Headquarters. Request RR:O02-1395. • Available from ASTM Headquarters. Request RR:D02-1396. c Available from ASTM Headquarters. Request RR:D02-1397.

Aeration rate Flow dudng test Pump mechanism Cooling

6. Apparatus 6.1 Jet Fuel Thermal Oxidation Tester~ (JFTOT)--Five models of suitable equipment may be used as indicated in Table 1. 6.1.1 Portions of this test may be automated. Refer to the appropriate user manual for the model JFTOT to be used for a description of detailed procedure. A manual is provided with each test rig, and the latest version of each manual is on file at ASTM as a Research Report. 6 See Table 1.

Thermocoupie (TC) Operating pressure System At test filter

Operating temperature For test Uniformity of run

N O ~ 1: Caution~No attempt should be made to operate the JFTOT without firstbecoming acquainted with all components and the function of each.

Calibration

6.1.2 Certain operational parameters used with the JFTOT instrument are critically important to achieve consistent and correct results. These are listed in Table 2., 6.2 Heater Tube DepOsit Rating Apparatus: 6.2.1 Visual Tube Rater, the tuberator described in'Annex AI.

600 mL of sample is aerated, then this aerated fuel is used to flU the reservoir leaving space for the piston; 450 ± 45 mL may be pumped In a valid test 1.5 L/rain dry air through sparger 3.0 ± 10 % mL/min (2.7 rain to 3.3 max) positive displacement, gear or piston s~nge bus bars fluid cooled to maintain consistent tube temperature profile Type J, fibre braid or Iconel sheathed 3.45 MPa ± 10 % on sample by pressurized inert gas (nitrogen) or by hydraulicallytransmitted force against control valve outlet restriction differential pressure (Ap) measured across test filter (by mercury manometer or by electronic trensducer) in mm Hg as stated in specification for fuel maximum deviation of ±2oC from specified temperature pore tin at 232"C (and for Models 230 and 240 only, pure lead at 327"C for high point and ice + water for low point reference)

NoTe 4: Warning--Do not inhale dust or ingest. May cause stomach disorder.

8. Standard Operating Conditions 8.1 Standard conditions of the test method are as follows: 8.1.1 Fuel Quantity, 450-mL minimum for test + about 50 mL for system. 8.1.2 Fuel Pre-treatment--Filtration through a single layer of general purpose, retentive, qualitative filter paper followed by a 6-rain aeration at 1.5 L/min air flow rate for a maximum of 600 mL sample using sparge stone of porosity C (see Test Method E 128). 8.1.3 Fuel System Pressure, 3.45 MPa (500 psi) _10 % gage. 8.1.4 Thermocouple Position, at 39 ram. 8.1.5 Fuel System Prefilter Element, filter paper of 0.45 ttm pore size.

7. Reagents and Materials 7.1 Use distilled (preferred) or deionized water in the spent sample reservoir as required for Model 230 and 240 JFTOTs. 7.2 Use methyl pentane, 2,2,4 trimethylpentane or nheptane (technical grade, 95 reel % minimum purity) as general cleaning solvent. This solvent will effectively clean internal metal surfaces of apparatus before a test, especially those surfaces (before the test section) that contact fresh sample. NOTe 2: Warning--Extremely flammable. Harmful if inhaled (see Annex A3).

7.2.1 Use trisolvent (equal mix of acetone (1), toluene, (2) isopropanol (3)) as a specific solvent to clean internal (working) surface of test section only.

CooI~ Bus Ba~

NffrE 3: Warning---(/) Extremely flammable, vapors may cause flash fire;(2) and (3) Flammable.Vapors of all three harmful.Irritating to skin, eyes and mucous membranes.

7.3 Use dry calcium sulfate + cobalt chloride granules (97 + 3 mix) in the aeration dryer. This granular material changes gradually from blue to pink color indicating absorption of water. e Originally supplied with apparatus and available from ALCOR Petroleum Instruments, Inc., Box 792222, San Antonio, TX 78279-2222. Now availablefrom ASTM as a research report. See Table 1.

FIG. 1

528

Standard Heater Section, Essential to All JFTOT Instruments

~

V

3241

8.1.6 Heater Tube Control Temperature, preset as specified in applicable specification. 8.1.7 Fuel Flow Rate, 2.7 to 3.3 mL/min, or 20 drops of fuel in 9.0 -t- 1.0 s. 8.1.8 Minimum Fuel Pumped During Test, 405 mL. 8.1.9 Test Duration, 150 ± 2 rain. 8.1.10 Cooling Fluid Flow, approximately 39 L/h, or center of green range on cooling fluid meter. 8 . l . l l Power Setting, approximately 75 to 100 on noncomputer models; internally set for computer models.

10.1.2 Differential Pressure Cell--StandarcYtze once a year or when installing a new cell (see Annex A2.2.6). 10.1.3 Aeration Dryer--Check at least monthly and change if color indicates significant absorption of water (see 7.3). 10.1.4 Metering Pump---Perform two checks of flow rate for each test as described in the Procedure section. 10.1.5 Filter Bypass Valve--For Models 202, 203, and 215--check for leakage at least once a year (see Appendix X5).

9. Preparation of Apparatus

11. Procedure

9.1 Cleaning and Assembly of Heater Test Section: 9.1.1 Clean the inside surface of the heater test section using a nylon brush saturated with trisolvent material to remove all deposits. 9.1.2 Check the heater tube to be used in the test for surface defects and straightness by referring to the procedure in Annex AI.10. Be careful, also, to avoid scratching tube shoulder during the examination since the tube shoulder must be smooth to ensure a seal under the flow conditions of the test. 9.1.3 Assemble the heater section using new items: (1) visually checked heater tube, (2) test filter and (3) three O-rings. Inspect insulators to be sure they are undamaged. NOTE 5--Heater tubes must not be reused. Tests indicate that magnesium migrates to the heater tube surface under normal test conditions. Surface magnesium may reduce adhesion of deposits to reused heater tube. 9.1.4 During assembly of heater section, handle tube carefully so as not to touch center part of tube. IF CENTER OF HEATER TUBE IS TOUCHED, REJECT T H E TUBE SINCE THE CONTAMINATED SURFACE MAY AFFECT THE DEPOSIT FORMING CHARACTERISTICS OF T H E TUBE. 9.2 Cleaning and Assembly of Remainder of Test Compo-

nents:

11.1 Preparation of Fuel Test Sample: 11.1.1 Filter and aerate sample using standard operating conditions (see Annex A2.2.8). NOTE 7--Before operating see Caution under Note 1. NOTE 8--Test method results are known to be sensitive to trace contamination from sampling containers. For recommended containers, refer to Practice D 4306. NOTE 9: Wm~aing--All jet fuels must be considered flammable except JP5 and JP7. Vapors are harmful (see Annex A3.3, A3.6, and A3.7). 11.1.2 Maintain temperature of sample between 15"C and 32"C during aeration. Put reservoir containing sample into hot or cold water bath to change temperature, if necessary. 11.1.3 Allow no more than 1 h to elapse between the end of aeration and the start of the heating of the sample.

11.2 Final Assembly: 11.2.1 Assemble the reservoir section (see User Manual). 11.2.2 Install reservoir and connect lines appropriate to the model JFTOT being used (see User Manual). 11.2.3 Remove protective cap and connect fuel outlet line to heater section. Do this quickly to minimize loss of fuel. 11.2.4 Check all lines to ensure tightness. 11.2.5 Recheck thermocouple position at 39 ram. 11.2.6 Make sure drip receiver is empty (Models 230 and 240 only).

11.3 Power Up and Pressurization:

9.2.1 Perform the following steps in the order shown prior to running a subsequent test. NOTE 6ult is assumed apparatus has been disassembled from previous test (see Annex A2 or appropriate user manual for assembly/ disassembly details). 9.2.2 Inspect and clean components that contact test sample and replace any seals that are faulty or suspect especially the: (1) lip seal on piston, and (2) O-rings on the reservoir cover, lines, and prefilter cover. 9.2.3 Install prepared heater section (as described in 9.1.1 through 9.1.4). 9.2.4 Assemble pre-filter with new element and install. 9.2.5 Check thermocouple for correct reference position, then lower into standard operating position. 9.2.6 On Models 230 and 240 make sure the water beaker is empty.

11.3.1 Turn POWER to ON. 11.3.2 Energize the AP alarms on models with manual alarm switch (Models 202, 203, and 215). 11.3.3 Pressurize the system slowly to about 3.45 MPa as directed in the User Manuals for Models 202, 203, and 215 (see also Annex A2.2.5). 11.3.4 Inspect the system for leaks. Depressurize the system as necessary to tighten any leaking fittings. 11.3.5 Set controls to the standard operating conditions. 11.3.6 Use a heater tube control temperature as specified for the fuel being tested. Apply any thermocouple correction from the most recent calibration (see Annex A2.2.7). NOTE 10--The JFTOT can be run to a maximum tube temperature of about 350"C. The temperature at which the test should be run, and the criteria for judging results are normally embodied in fuel specifications.

11.4 Start Up:

10. Calibration and Standardization Procedure 10.1 Perform checks of key components at the frequency indicated in the following (see Annexes or user manual for details). 10.1.1 Thermocouple--Calibrate a thermocouple when first installed and then normally every 30 to 50 tests thereafter, but at least every 6 months (see Annex A2.2.8).

11.4.1 Use procedure for each model as described in the appropriate User Manual. 11.4.2 Some J F T O T models may do the following steps automatically, but verify that: 11.4.2.1 No more than 1 h maximum elapses from aeration to start of heating. 11.4.2.2 The manometer bypass valve is closed as soon as 529

~

D 3241 11.8.3.2 Discard fuel to waste disposal.

the heater tube temperature reaches the test level, so fuel flows through the test filter (see Annex A2.2.6). 11.4.2.3 Manometer is set to zero (see Annex A2.2.6). 11.4.3 Check fuel flow rate against Standard Operating Conditions by timing flow or counting the drip rate during first 15 rain of test.

12. Heater Tube Evaluation 12.1 Visually rate the deposits on heater tube in accordance with Annex A 1. 12.2 Return tube to original container, record data, and retain tube for visual record as appropriate.

NOTE I l--When counting drop rate,the firstdrop is counted as drop 0, and time is started.As drop 20 falls,total time is noted.

11.5 Test: 11.5.1 Record filter pressure drop every 30 rain minimum during the test period. 11.5.2 If the filter pressure drop begins to rise sharply and it is desired to run a full 150 rain test, a bypass valve common to all models must be opened in order to finish the test. See appropriate User Manual for details on operation of the bypass system (see Annex A2.2.2). 11.5.3 Make another flow check within final 15 rain before shutdown (see 11.4.3 and accompanying note). 11.6 Heater Tube Profile--lf a heater tube temperature profile is desired, obtain as described in Appendix X4. 11.7 Shutdown: 11.7.1 For Models 202, 203, and 215 only: 11.7.1.1 Switch HEATER, then PUMP to OFF. 11.7.1.2 Close NITROGEN PRESSURE VALVE and open MANUAL BYPASS VALVE. 11.7.1.3 Open NITROGEN BLEED VALVE slowly, if used, to allow system pressure to decrease at an approximate rate of 0.15 MPa/s. 11.7.2 Models 230 and 240 shut down automatically. 11.7.2.1 After shutdown, turn FLOW SELECTOR VALVE to VENT to relieve pressure. 11.7.2.2 Piston actuator will retreat automatically. 11.7.2.3 Measure effluent in drip receiver, then empty. 11.8 Disassembly: 11.8.1 Disconnect fuel inlet line to the heater section and cap to prevent fuel leakage from reservoir. 11.8.2 Disconnect heater section. 11.8.2.1 Remove heater tube from heater section carefully so as to avoid touching center part of tube, and discard test filter. 11.8.2.2 Flush tube with solvent material from top down while grasping tube at bottom and holding vertically. Allow to dry, return tube to original container, mark with identification and hold for evaluation. 11.8.3 Disconnect reservoir. 11.8.3.1 Measure the amount of spent fluid pumped during the test, and reject the test if the amount is less than 405 mL.

13. Report 13.1 Report the following: 13.1.1 The heater tube control temperature. This is the test temperature of the fuel. 13.1.2 Heater tube deposit rating(s). 13.1.3 Maximum pressure drop across the filter during the test or the time required to reach a pressure differential of 25 ram Hg. For the Model 202, 203 JFTOT, report the maximum recorded AP found during the test. 13.1.4 If the normal 150 rain test time was not completed, for example, if the test is terminated because of pressure drop failure, also report the test time that corresponds to this heater tube deposit rating. Nox~ 12--Eitherthe tube rating or the AP criteria, or both, are used to determinewhethera fuel samplepasses or failsthe test at a specified test temperature. 13.1.5 Spent fuel at the end of a normal test. This will be the amount on top of floating piston or total fluid in displaced water beaker, depending on model of JVrOT used.

14. Precision and Bias 14.1 An interlaboratory study of JFTOT testing was conducted in accordance with Practice E 691 by eleven laboratories, using thirteen instruments including two JFTOT models with five fuels at two temperatures for a total of ten materials. Each laboratory obtained two results from each material. See ASTM Research Report No. D02:1309. 14.1.1 The terms repeatability and reproducibility in this section are used as specified in Practice E 177. 14.2 Precision--The precision of this procedure for determining the thermal oxidative stability of aviation turbine fuels is being determined. 14.3 Bias--This test method has no bias because jet fuel thermal oxidative stability is defined only in terms of this test method. 15. Keywords 15.1 differential pressure; fuel decomposition; oxidative deposits; test filter deposits; thermal stability; turbine fuel

ANNEXES

(Mandatory Information) A1. TEST METHOD FOR VISUAL RATING OF JZI'OT HEATER TUBES

AI.I Scope A 1.1.1 This method covers a procedure for visually rating the heater tube produced by Test Method D 3241, JVrOT Procedure.

AI.1.2 The final result from this test method is a tube color rating based on an arbitrary scale established for this test method plus two additional yes/no criteria that indicate

530

(~ D 3241 the presence of an apparent large excess of deposit or an unusual deposit, or both.

AI.8.5 Evaluators--Use persons who can judge colors, that is, they should not be color blind.

A1.2 Referenced Documents AI.2.1 Adjunct: Color Standard for Tube Deposit Rating5

A1.9 Calibration and Standardization Procedure AI.9.1 No standardization is required for this test apparatus, but since the Color Standard is known to fade, store it in a dark place. NOTE AI.2--The lifetimeof the Color Standard is not establ/shed when continuouslyor intermittentlyexposedto fight.It is goodpractice to keep a separate Standard in dark (no fight) storage for periodic comparison with the Standard in regular use. When comparing, the optimum under the light conditionsare those of the tube rating box. A 1.9.2 Standardization of Rating Technique: AI.9.2.1 In rating a tube, the darkest deposits are most important. Estimate grades for the darkest uniform deposit, not for the overall average color of the deposit area. A 1.9.2.2 When grading, consider only the darkest continuous color that covers an area equal or larger than a circle of size one-half the diameter of the tube. AI.9.2.3 Ignore a deposit streak that is less in width than one-quarter the diameter of the tube regardless of the length of the streak. A 1.9.2.4 Ignore spots, streaks, or scratches on a tube that are considered tube defects. These will normally not be present since the tube is examined before use to eliminate defective tubes.

A1.3 Terminology AI.3.1 abnormalma tube deposit color that is neither peacock nor like those of the Color Standard. A 1.3.1.1 Discussion--This refers to deposit colors such as blues and grays that do not match the Color Standard. A 1.3.2 peacockmA multicolor, rainbow-like tubedeposit. AI.3.2.1 Discussion--This type of deposit is caused by interference phenomena where deposit thickness exceeds the quarter wave length of visible light. AI.3.3 Tube Rating--A ten step discrete scale from 0 to >4 with intermediate levels for each number starting with 1 described as less than the subsequent number. A1.3.3.1 Discussion--The scale is taken from the five colorsm0, 1, 2, 3, 4--on the ASTM Color Standard. The complete scale is: 0, <1, 1, <2, 2, <3, 3, <4, 4, >4. Each step is not necessarily of the same absolute magnitude. The higher the number, the darker the deposit rating. A1.4 Summary of Test Method A 1.4.1 This test method uses a specially constructed light box to view the heater tube. The tube is positioned in the box using a special tube holder. Uniformity of the new tube surface is judged under the optimum light conditions of the box. Color of the tube is judged under light and magnification by comparing to the Color Standard plate slid into optimum position immediately behind the tube.

AI.10 Pretest Rating of Tubes AI.10.1 Inspect the heater tube for defects in the center (thinner) area of the tube, and reject any tube that shows scratches, dull, or unpolished areas or other defects visible to the naked eye. Al.10.2 If a tuberator is to be used to rate the tube after the test, examine the new tube using the rating device as appropriate to establish a base line or condition of satisfactory starting quality. See AI.I 1.1 through AI.11.1.3. Al.10.3 Examine the tube for straightness by rolling the tube on a flat surface and noting the gap between the flat surface and the center section. Reject any bent tube.

A1.5 Significance and Use AI.5.1 The final tube rating is assumed to be an estimate of condition of the degraded fuel deposit on the tube. This rating is one basis for judging the thermal oxidative stability of the fuel sample.

A I . U Procedure A I . l l . I Set Up: A 1.11.1.1 Snap the upper end of the heater tube into the clamp of the holder for the heater tube. AI.11.1.2 Push the heater tube against the stop of the holder for the heater tube.

A1.6 Apparatus

A1.6.1 Heater Tube Deposit Rating ApparatusmThe colors of deposits on the heater tube are rated by using a tuberator and the ASTM Color Standard.

Ai.7 Test Samples (Coupons) AI.7.1 Handle the heater tube coupon carefully so as not to touch the center portion at any time. Ncyr~ A1.l--Touching the center of the coupon will likelycontaminate or disturb the surfaceof the tube, deposit, or both, which must be evaluatedin pristine condition.

,r~.A,x

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guide rod into the tuberator. A I. I 1.1.4 Rotate the holder and position the heater tube such that the side with the darkest deposit is visible. Al.II.l.5 Insert the ASTM Color Standard into the tuberator. AI. 11.2 Evaluation: A1.11.2.1 Compare the darkest heater tube deposit color with the ASTM Color Standard. A1.11.2.2 When the darkest deposit color corresponds exactly to a color standard, that number should be recorded. AI.11.2.3 If the darkest heater tube deposit color being rated is in the obvious transition state between any two adjacent color standards, the rating should be recorded as less than the darker (that is, higher number) standard.

A1.8 Standard Operating Conditions AI.8.1 Inside of Light Box, opaque black. A1.8.2 Light Source, three 30 W incandescent bulbs, reflective type; all must be working for optimum viewing. AI.8.3 Bulb Positions, two above, one below, each directed toward tube holder and color standard. A1.8.4 Magnification, 3×, covering viewing window. 531

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D 3241 A1.12.2 Examples: A1.12.2.1 Example l m A heater tube has a maximum deposit falling between Color Standard Codes 2 and 3 with no other colors present. The overall tube rating would be less than 3. A1.12.2.2 Example 2 ~ T h e darkest deposit on a tube matches a Code 3, but there is also a peacock deposit present. The overall rating of the tube would be reported as 3P. A1.12.2.3 Example 3--A heater tube has a deposit that matches Color Standard Code 1 and also has an abnormal deposit. The overall tube rating would be reported as 1A.

A 1.11.2.4 In the event the heater tube has deposits which do not match the normal Color Standard colors, use the following rules for rating. With reference to standard terms: (1) If the deposit is peacock color, rate this as Code P, but also rate any deposit that shows normal deposit color; or: (2) If the deposit contains an abnormal color, rate this as Code A, but also rate any deposit that shows normal deposit color. AI.I 1.3 Remove the rated heater tube and return to its original container. AI.12 Report A 1.12.1 Report the numerical rating for the heater tube plus A or P, or both, with additional description, if applicable. AI.12.1.1 When reporting the overall rating, report the maximum rating, and, if there are colors present which do not match the Color Standard, report these also. A1.12.1.2 If there are only P or A, or both, deposits, report only these and do not attempt to estimate a numerical grade.

AI.13 Precision and Bias A I.13.1 PrecisionmThe precision of the procedure in Test Method D 3241 for measuring tube deposit rating is being determined. A I. 13.2 B/as--The procedure in Test Method D 3241 for determining tube deposit rating has no bias because the value of tube deposit rating is defined only in terms of the test method.

A2. EQUIPMENT heater tube can be evaluated based on a complete test. A2.2.2.1 The heart of the test system is the tube-in-shell heat exchanger, or test section, which holds the test coupon and directs flow of fuel over it. It is important for the heater tube to be aligned correctly in the heater test section as shown in Fig. A2.1. This component is critical to consistent results and is a common component in all JFTOT models. A2.2.2.2 There are some other points regarding the fuel system that deserve mention: (1) Fresh fuel is filtered immediately out of the reservoir through 0.45 ~tm membrane filter paper before entering the heater test section; (2) The heater tube is sealed in the heater test section by elastomer O-rings; (3) The test filter is of stainless steel of 17 ~tm rated porosity. If this filter causes an increase in differential

A2.1 Test Instrument A2.1.1 The instrument described in this annex is the Jet Fuel Thermal Oxidation Tester, or JFTOT, that is used to test the thermal oxidation stability of turbine fuel. There are five models of JFTOT which will be described. All provide a means to pump the sample once through the test system across the metal test coupon and through a test filter. There are means to control and measure coupon temperature, system pressure, and pressure drop across the fdter, and methods of control and measurement vary with each model of JFTOT. Mechanism for pumping is positive displacement using a gear pump or piston pump. A2.2 Test Details A2.2.1 GeneralDescription--This instrument uses a fixed volume of jet fuel that has been filtered, then aerated to provide a sample saturated with air. During the test, fuel is pumped at a steady rate across a heated aluminum tube which is maintained at a relatively high temperature, typically 260"C, but higher under some specifications. The fuel, saturated with oxygen from the aeration, may degrade on the hot aluminum heater tube to form deposits as a visible film. Also, the degraded materials of the fuel may flow downstream and be caught by the test filter. Both the increase in differential pressure across the test filter and the final heater tube rating are used to determine the oxidative stability of the fuel. A2.2.2 Fuel System--Freshly filtered and aerated fuel is initially placed in a reservoir, then circulated once through the apparatus to a spent sample receptacle. Motive force for the sample is a positive displacement pump that will maintain flow at 3.0 mL/min and overcome any tendency of initial filter blockage from affecting the flow rate. Deviation of 10 % in flow rate is permitted. If filter blockage becomes severe, the bypass valve located before the test filter can be opened in order to finish the test. Then, any deposit on the

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pressure, an alarm will sound (normally at 125 mm Hg) alerting the operator. Bypass of the filter can then be accomplished if desired; (4) Models 202, 203, and 215 JFTOT's use a single fuel reservoir with a floating piston to separate the fresh fuel (in bottom) and spent fuel (on top). Models 230 and 240 use two reservoirs, one for fresh fuel and one for spent; (5) Flow of fuel in all models can be monitored by visually counting drops of flow. Model 230 and 240 JFTOT's also allow volumetric measure of flow with time which is considered the most accurate flow measure. A2.2.2.3 Diagrams of fuel flow though the three main configurations of JFTOT are shown in Fig. A2.3. A2.2.3 Heating/Temperature Control System--The heater tube is resistively heated by the conductance of high amperage, low voltage current from a transformer through the aluminum tube. The heater tube is clamped to relatively heavy, water cooled current conducting bus bars which increase in temperature relatively little. A2.2.3.1 The temperature controller in all models of JFTOT serves as indicator and controller. In automatic mode, the controller provides a source of steady heat during the test varying the power as necessary to maintain the target (setpoint) temperature. In manual mode, the controller provides temperature indication only. Temperature range of

operation is from ambient to a maximum of about 350"C. A2.2.3.2 Critical to temperature control is the thermocouple and its position. The thermocouple itself must be calibrated to ensure acceptable accuracy. The position of the tip must be carefully placed so the temperature reading during automatic control is the maximum (the hottest spot) for the heater tube. A simple mechanical positioning system allows easy and accurate placement of the thermocouple. A2.2.3.3 A diagram of the basic heating system is shown in Fig. A2.4. A2.2.4 Cooling System--In the normal operation of the JFTOT, some cooling is necessary to remove heat going into the bus bars by conduction from the hot heater tube. Cooling water is circulated through each bus bar using either laboratory tap water (Models 202, 203, and 215 JFTOT) or an internally circulated and radiator cooled liquid system (Models 230 and 240). The only precautions with these systems is to monitor them to be sure they are working and to avoid use of coolants that contain contaminants or salts that may eventually foul the system. A2.2.5 Pressurization--At the temperature of a normal JFTOT test, jet fuel would typically boil at the temperature of the heater tube. This would prevent accurate temperature control and interfere with natural deposit formation. Therefore, the system must be operated under a total pressure of about 3.45 MPa (500 psi). This pressure level is accomplished in each model by either using nitrogen gas (Models 202, 203, and 215) or a hydraulic piston pump (Models 230 and 240) to produce the high pressure needed. A2.2.5.1 A pressure gage or transducer is used to measure and allow monitoring of the total system pressure. Of particular note is that the gas pressurized systems are run closed after pressurization whereas the hydraulically pressurized systems have a relief valve through which the fluid pa~ses in a constant leak throughout the test. For the relief valve control to operate uniformly for any fuel, a displacement cell is used where the spent fuel enters the top displacing water out the bottom and through the relief valve. Since the valve sees only water, the valve works consistently. A2.2.6 Differential Pressure MeasuremThere are two instrument configurations used in JFTOT models to measure differential pressure (AP) across the test fdter as products of fuel degradation are caught by the filter during the test. Models 202 and 203 (before 1984) use a mercury manometer with a possible strip chart Ap recording option. Models 215, 230, and 240 use an electronic AP transducer. Details of how these two methods are included in the fuel schematic can be seen in the diagrams under Fuel System (see Fig. A2.3). A2.2.6.1 Proper use of these differential measuring devices requires two special actions: bypass and air bleeding. The first allows the fuel flow to bypass the falter whenever that action becomes necessary. The second is used to remove air or nitrogen that at times may become trapped in the cell chambers. The manometer output is read as the height of the column of mercury; the transducer output must be displayed digitally. A2.2.6.2 The manometer system, by nature, includes a bias due to the presence of fuel instead of the usual air over the mercury. This changes the value of pressure expressed in terms of column height of mercury such that a result about 6 % higher than true occurs. The transducer is not subject to 533

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this error, so in order to have manometer and transducer models read the same, a 6 % bias is added to the transducer so it gives the same value as a manometer. A2.2.6.3 When operated, the AP measuring device employed must b¢ zeroed under actual flow conditions at the start of the test. This is because a small pressure drop is

created across the system when fuel is flowing. Zeroing the transducer or manometer at the beginning o f the test compensates for the flow.

A2.2.7 Differential Pressure Measurement Standardization-The AP measurement accuracy can b¢ checked by a technique of reading the pressure created by a column of 534

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known density fluid on each side of the AP cell. The details for doing this are included as part of each operating manual for the particular model JFTOT. This standardization is really a verification that the AP cell is operating correctly and is not meant to be a true calibration of the cell. Calibration must be done by the manufacturers of the cell if such action is suggested based on the results of the standardization. A2.2.8 Thermocouple Calibration--It is important for the

O 3241

thermocouple to be accurate. To ensure this value, a method of calibration against known melting points is used and is described in detail in the appropriate User Manual for each JFTOT. With the first JFTOT models, only pure tin was used as the indicator metal. Starting with JFTOT Models 230 and 240 the use of two metals, pure tin at 232"C and pure lead at 327"C, was initiated to define two points surrounding the normal range used with the instrument. Also, an ice-water mixture is used to establish a 0*C low reference point. A2.2.8.1 The principle used with melting point of metals is to immerse the thermocouple tip in the melted metal, then allow the metal to cool. As the metal goes through its freeze point, the temperature reading will hesitate momentarily indicating the known point for the metal. A2.2.8.2 The difference between the known metal freezing value and the displayed temperature becomes a correction for setting test temperatures. For example, using tin with a known freeze temperature of 232"C, if the temperature noted at the time the metal froze was higher than 232", then this would indicate the thermocouple was reading high by the difference indicated and the applied correction would be to lower any test temperature by this same amount. Where two metals and ice water (low point) are used the principle is the same but the correction is calculated and applied automatically by the internal computer. A2.2.9 Fuel Aeration System--All JFTOT models have means to aerate the sample prior to testing. Without the presence of oxygen in the sample, a proper test is not achieved. Filtered, dry air is metered through the sample at about 1.5 L/min rate for 6 rain. This 9 L of air ensures 97 % saturation of the sample. A2.2.10 Elapsed Time Measurement--There are various methods of timing the test depending on the model of JFTOT. The elapsed time indicator is normally the basis used, but in some models the timing of the AP data collection is done with a different timer. Since these two timers may not be exactly the same, the last data point may be lost if the test stops before the last timed data point. The user manuals for the various instrument models cover techniques for avoiding loss of data points.

A3. PRECAUTIONARY STATEMENTS A3.2.5 Swallowing may cause injury, illness, or death. A3.2.6 Avoid prolonged or repeated contact with skin. A3.2.7 Do not get in eyes. A3.2.8 Can produce toxic vapors on contact with flames, hot glowing surfaces, or electric arcs.

A3.1 Acetone A3.1.1 Keep away from heat, sparks, and open flame. A3.1.2 Keep container closed. Use with adequate ventilation. A3.1.3 Avoid buildup of vapors and eliminate all sources of ignition, especially nonexplosion-proof electrical apparatus and heaters.

A3.3 Iso-propanol (2-propanol) A3.3.1 Keep away from heat, sparks, and open flame. A3.3.2 Keep container away from heat, sparks, and open flame. A3.3.3 Keep container closed. A3.3.4 Use with adequate ventilation. A3.3.5 Avoid buildup of vapors and eliminate all sources of ignition, especially nonexplosion-proof electrical apparatus and heaters.

A3.2 Toluene A3.2.1 Avoid prolonged or repeated breathing of vapor or spray mist. A3.2.2 Use only with adequate ventilation. A3.2.3 Eye irritation and dizziness are indications of overexposure. A3.2.4 Do not take internally. 535

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D 3241 A3.6 Aviation Turbine Fuel (Jet B, See Specification D 1655) A3.6.1 Keep away from heat, sparks, and open flames. A3.6.2 Keep container closed. A3.6.3 Use with adequate ventilation. A3.6.4 Avoid breathing vapor or spray mist. A3.6.5 Avoid prolonged or repeated contact with skin.

A3.3.6 Avoid prolonged breathing of vapor or spray mist. A3.3.7 Avoid prolonged or repeated skin contact. A3.4 n-heptane A3.4.1 Keep away from heat, sparks, and open flame. A3.4.2 Keep container closed. A3.4.3 Use with adequate ventilation. A3.4.4 Avoid prolonged breathing of vapor or spray mist. A3.4.5 Avoid prolonged or repeated skin contact.

A3.7 Aviation Turbine Fuel (Jet A or A-l, See Specification D 1655) A3.7.1 Keep away from heat, sparks, and open flame. A3.7.2 Keep container closed. A3.7.3 Use with adequate ventilation. A3.7.4 Avoid buildup of vapors and eliminate all sources of ignition, especially nonexplosion-proof electrical apparatus and heaters. A3.7.5 Avoid breathing vapor or spray mist. A3.7.6 Avoid prolonged or repeated contact with skin.

A3.5 Compressed Gases (Nitrogen) A3.5.1 Keep cylinder valve closed when not in use. A3.5.2 Do not enter storage areas unless adequately ventilated. A3.5.3 Always use a pressure regulator. A3.5.4 Release regulator tension before opening cylinder. A3.5.5 Do not transfer to cylinder other than one in which gas is received. A3.5.6 Do not mix gases in cylinders. A3.5.7 Never drop cylinder. A3.5.8 Make sure cylinder is supported at all times. A3.5.9 Stand away from cylinder outlet when opening cylinder valve. A3.5.10 Keep cylinder out of sun and away from heat. A3.5.11 Keep cylinder from corrosive environment. A3.5.12 Do not use cylinder without label. A3.5.13 Do not use dented or damaged cylinders. A3.5.14 For technical use only. A3.5.15 Do not use for inhalation purposes.

A3.8 Mercury A3.8.1 Do not breathe vapor. A3.8.2 Keep container closed. A3.8.3 Use with adequate ventilation. A3.8.4 Do not take internally. A3.8.5 Cover exposed surfaces with water if possible, to minimize evaporation. A3.8.6 Do not heat. A3.8.7 Keep recovered mercury in tightly sealed container prior to sale or purification. A3.8.8 Do not discard in sink or in rubbish. A3.9 Lead, Tin Metals

APPENDIXES

(Nonmandatory Information) X1. INSTALLATION, MAINTENANCE, SPECIAL CHECKS XI.I Laboratory Installation Requirements

DRAIN to a'drain having a minimum capacity to receive 80 L/h.

X 1.1. I The tester should be placed on a level laboratory bench, allowing a 200 to 300 mm wide bench area in front of the tester. Ready access to the rear of the tester should be provided for routine maintenance and service requirements. Ensure that the vent on top or side of the JFTOT cabinet is not obstructed during installation or use. Adequate ventilation should be provided, and proper procedures for handling solvents and hydrocarbons should be used. A constant voltage transformer may be required by early versions of the instrument. Single-phase electrical power, 115 V-60 Hz-15 Amp or optional 220V-50 Hz-8 Amp with a ground outlet is required. X 1.1.2 For pneumatic model JFTOT's, a nitrogen supply bottle with a suitable regulator capable of supplying 3.45 MPa should be placed conveniently and connected with 3.2-mm diameter tubing to the tester. A suitable 6.4-mm diameter line needs to be connected from the WATER INLET connection to a 200 to 700 kPa water supply and a 6.4-ram diameter line needs to be connected from WATER

X1.2 AutoCai Calibrator Metal Replacement X I.2.1 The tin (and lead, if used) in the well of the AutoCal Calibrator must be replaced whenever the quantity is below minimum or when contaminated. XI.2.2 To remove the metal, install the AutoCal Calibrator inverted between the upper fixed bus and the lower floating bus. X1.2.3 Place a paper tissue or rag under the well to catch the molten metal. X 1.2.4 Apply power to the AutoCal Calibrator as during normal calibration, and at same time gently tap the well until all molten metal has dropped out. XI.2.5 Remove and install the AutoCal Calibrator in upright position and refill with new metal. The proper amount of tin for one filling is about 1.5 to 1.9 g, and for lead about 3.3 to 4.7 g. X1.3 Thermocouple Replacement and Position Adjustment XI.3.1 The thermocouple used for measuring and con536

(~ D 3241 X1.5.5 The time required for the AP to exceed 100 mm can be quite short; in some equipment the increase may occur almost instantly depending on pump condition and system details. Such a rapid rise in AP is acceptable and considered to be within the range of expected and normal operation. XI.5.6 If the time measured to reach I00 m m AP exceeds 60 s, either the filter bypass valve is leaking or the fuel metering p u m p performance is unsatisfactory. In this case, the fuel metering p u m p performance should be checked to determine if the p u m p or filterbypass valve needs to be replaced.

trolling the temperature of the JFTOT heater tube may have to be replaced at intervals due to damage or failure. If not ot the simple plug in type, remove the thermocouple, loosen the thermocouple damp, support clamp, and thermocouple connections on back of the temperature controller. XI.3.2 Install a new thermocouple reversing the steps used to remove old thermocouple. Replace and tighten screws as required. If applicable, when tightening the Allen screw of thermocouple damp, the tip of the thermocouple must be flush with top of upper fixed bus when position indicator is set at the reference mark. XI.3.3 Check for proper thermocouple indexing under actual test operating conditions.

XI.6 Fuel Metering P u m p Check (Gear Pumps Only) XI.6.1 Install a plugged filter, used heater tube, and establish normal fuel flow. XI.6.2 After steady flow is established, adjust the M A N B Y P A S S valve to maintain a steady A P of 50 m m . XI.6.3 Measure the time with a stopwatch for 20 drops flow rate as observed in the sight glass. X 1.6.4 The time for a properly performing fuel p u m p is 9.0 ± 1.0 s for 20 drops fuel flow rate. Pumps that measure above I0 s should be replaced. XI,6.5 After installing a new pump, repeat the p u m p check. XI.6.6 If low flow persists,dean all lines and fittingsfrom the test filterthrough the metering p u m p to the fuel reservoir with tri-solv.Replace lines as necessary. Repeat p u m p check.

X1.4 Heater Tube Temperature Profile X 1.4.1 If it is desired to measure the heater tube temperature profile, do so after the first hour of the test or before significant AP occurs. Follow the procedure in the user manual for the particular model JFTOT. X1.5 Filter Bypass Valve Leakage Check (Models 202, 203, and 215 only) X1.5.1 Obtain a used filter and plug the upstream side with any fast-drying glue such as industrial adhesive. Install this filter together with any heater tube in the test section. X1.5.2 Circulate clean filtered fuel at 3.45 MPa with MAN BYPASS valve in the open position (no heat applied). XI.5.3 After steady flow is observed in the sight glass (20 drops in 9.0 ± 1.0 s), close the MAN BYPASS valve and simultaneously start a stopwatch. Observe the time required for the AP to reach 100 ram. Immediately open the MAN BYPASS valve to resume normal fuel flow. X1.5.4 If the time measured to reach 100 mm AP is equal to or less than 60 s, the MAN BYPASS valve and the fuel pump meet normal performance requirements.

XI.7 Maintenance Manual

XI.7. I A maintenance manual is avad"able6 that provides additional maintenance information, such as the electrical schematic (also available on inside of back door of 3 F T O T cabinet). Complete details for operating the J F T O T models are contained in the user manuals for each instrument.

X2 DETERMINATION OF BREAKPOINT X2.1 Definition

X2.2 Determination of Breakpoint

X2.1.1 Breakpoint--In Test Method D 3241 (JFTOT), breakpoint is the highest control temperature at which the

X2.2.1 The breakpoint can be derived by conducting a series of tests of different control temperatures to arrive at the temperature, x'C, at which the fuel meets both tube rating and AF specification requirements, and where a test at a control temperature of (x + 5)0C would result in a fail (that is, failure to meet tube rating or AF requirements). The temperature x*C would then be reported as the Test Method D 3241 breakpoint,

fuel meets tube rating and AP specification requirements. X2.1.1.1 DiscussionmThis definition of breakpoint describes the highest pass temperature for a fuel. Note that some published papers have used the term breakpoint to describe the lowest fail temperature, which is the (x + 5)*C temperature referred to below.

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this atendard. Users of this standard are expressly advised that datarmlnatlon of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years end ff not revised, either reepproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards end should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 100 Barr Harbor Drive, West Conshohocken, PA 19428.

537

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Designation:D 3246 - 96

An American National Standard

Standard Test Method for Sulfur in Petroleum Gas by Oxidative Microcoulometry I This standard is issued under the fixed designation D 3246; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reappmval. A superscript epsilon (0 indicates an editorial change since the last revision or re.approval.

3.2 The reaction occurring in the titration cell as sulfur dioxide enters is: 13- + S O 2 + H 2 0 --* S O 3 + 3I- + 2H÷ (1) The triiodide ion consumed in the above reaction is generated coulometrically thus: 3I- --* Is- + 2e(2) 3.3 These microequivalents of triiodide (iodine) are equal to the number of microequivalents of titratable sample ion entering the titration cell. 3.4 A liquid blend containing a known amount of sulfur is used for calibration.

1. Scope I. 1 This test method covers determination of sulfur in the range from 1.5 to 100 mg/kg (ppm by mass) by weight in hydrocarbon products that are gaseous at normal room temperature and pressure. NffrB l - - T b e test m e t h o d has been tested cooperatively only on

high-purity ethylene gas. Precision data have not been developed for other products. 1.2 The values stated in SI units are to be regarded as the standard. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

4. Significance and Use 4.1 Trace quantities of sulfur compounds in hydrocarbon products can be harmful to many catalytic chemical processes in which these products are used. Maximum permissible levels of total sulfur are normally included in specifications for such hydrocarbons. It is recommended that this test method be used to provide a basis for agreement between two laboratories when the determination of sulfur in hydrocarbon gases is important. 4.2 On liquefied petroleum gas, total volatile sulfur is measured on an injected gas sample. For such material a liquid sample must be used to measure total sulfur.

2. Referenced Documents

2.1 A S T M Standards: D 1265 Practice for Sampling Liquified Petroleum (LP) Gases--Manual Method 2 D 1193 Specification for Reagent Water 3 D 3120 Test Method for Trace Quantifies of Sulfur in Light Liquid Petroleum Hydrocarbons by Oxidative Microcoulometry4 F 307 Practice for Sampling Pressurized Gas for Gas Analysis5 2.2 Other Standards: Compressed Gas Association Booklets G-4 and G-4-1 on the Use of Oxygen. 6

5. Interferences 5.1 This test method is applicable in the presence of total halide concentrations of up to 10 times the sulfur level and total nitrogen content of up to 1.0 %. Free nitrogen does not interfere. 5.2 This test method is not applicable in the presence of total heavy metal concentrations (for example, Ni, V, Pb, etc.) in excess of 500 mg/kg. NOTE 2--To attain the quantitative detectabilitythat the method is capable of, stringent techniques should be employed and all possible sources of sulfur contamination must be eliminated.

3. Summary of Test Method 3.1 A sample is injected into a combustion tube maintained at about 800"C having a flowing stream of gas containing about 80 % oxygen and 20 % inert gas (for example, nitrogen, argon, etc,). Oxidative pyrolysis converts the sulfur to sulfur dioxide which then flows into a titration cell where it reacts with triiodide ion present in the electrolyre. The triiodide thus consumed, is coulometrically replaced and the total current required to replace it is a measure of the sulfur present in the sample injected.

6. Apparatus 7~ 6.1 Pyrolysis FurnacewThe sample should be pyrolyzed

' This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittce D02.D 0.02 on C3 Test Methods. Current edition approved Nov. 10, 1996. Published January 1997. Ori~nally published as D 3246 - 73 T. Last previous edition D 3246 - 92. 2 Annual Book of Ab'WM Standards, Vo105.01. 3 Annual Book of A~l'M Standards, Vol 1!.01. 4 Annual Book of ASTM Standards, Vo105.02. s Annual Book of ASTM Standards, Vol 15.03. e Available from Compressed Gas Association, 1235 Jefferson Davis Hwy., Arlington, VA 22202.

The apparatus dea~ibed in 6.1 to 6.5 inclusive, is similar in specifications to equipment available from Tekmar.Dohrmann, 7143 E. Kempe~ ltd., Cincinnati, OH 524549. For further detailed discussions, in equipment, see: Preprints-Division of Petroleum Chemistry, American Chemical Society, Vol !, No. 3, Sept. 7-12, 1969, p. 11232 "Determination of Sulfur, Nitrogen, and Chlorine in Petroleum by Microcoulomet~," by Harry V. Drushel. mTeknusr-Dohrmaen is the sole source of supply of the apparatus known to the committee at this time. If you are aware of alternative supplier& please provide information to ASTM Headquarters. Your comments will receive carefid consideration at a meeting of the responsible technical committee,t which you may attend.

538

~

O 3246

in an electric furnace having at least two separate and independently controlled temperature zones, the first being an inlet section that can maintain a temperature sufficient to volatilize all the organic sample. The second zone shall be a pyrolysis section that can maintain a temperature sufficient to pyrolyze the organic matrix and oxidize all the organically bound sulfur. A third outlet temperature zone is optional. 6.1.1 Pyrolysis furnace temperature zones for light liquid petroleum hydrocarbons should be variable as follows: Inlet zone Center pyrolysis zone Outlet zone (optional)

up to at least 700"C up to at least 1000"C up to at least 800"C

6.2 Pyrolysis Tube, fabricated from quartz and constructed in such a way that a sample, which is vaporized completely in the inlet section, is swept into the pyrolysis zone by an inert gas where it mixes with oxygen and is burned. The inlet end of the tube shall hold a septum for syringe entry of the sample and side arms for the introduction of oxygen and inert gases. The center or pyrolysis section should be of sufficient volume to assure complete pyrolysis of the sample. 6.3 Titration Cell, containing a sensor-reference pair of electrodes to detect changes in triiodide ion concentration and a generator anode-cathode pair of electrodes to maintain constant triiodide ion concentration and an inlet for a gaseous sample from the pyrolysis tube. The sensor electrode shall be platinum foil and the reference electrode platinum wire in saturated triiodide half-cell. The generator anode and cathode half-cell shall also be platinum. The titration cell shall require mixing, which can be accomplished through the use of a magnetic stirring bar, stream of inert gas, or other suitable means. NOI"E 3: C a u t | o n n E x c e s s i v e speed will decouple the stirring bar,

causing it to rise in the cell and damage the electrodes.The creation of a slight vortex is adequate. 6.4 Microcoulometer, having variable attenuation gain control, and capable of measuring the potential of the sensing-reference electrode pair, and comparing this potential with a bias potential, amplifying the potential difference, and applying the amplified difference to the working-auxiliary electrode pair so as to generate a titrant. Also the microcoulometer output voltage signal shall be proportional to the generating current. 6.5 Recorder, having a sensitivity of at least 0.1 mV/25 m m with chart speeds of 12 to 25 ram/rain. Use of a suitable electronic or mechanical integrator is recommended but optional. 6.6 Sampling Syringe for Liquid--A microlitre syringe of 10-1~L capacity capable of accurately delivering 1 to 10 ~tL of liquid blend into the pyrolysis tube 75 mm by 24-gage needles are recommended to reach the inlet zone of the pyrolysis furnace.

7. Reagents and Materials

7.1 Purity of Reagents--Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, where such specifications are available? Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination. 7.2 Purity of Water--The water used in preparing the cell electrolyte should be demineralized or distilled or both. Water of high purity is essential. See Specification D 1193 for reagent water. NOTE 5--DistiUed water obtained from an all borosilicateglass still, fed from a deminerallzer, has proven very satisfactory. 7.3 Acetic Acid (rel dens 1.05)mConeentrated acetic acid (CH3COOH). NOTe 6: W a r n i n g - - M a y cause burns. See Annex A I . I .

7.4 Argon, Helium, or Nitrogen, high-purity grade (HP), I° used as the carrier gas. NOTe 7: W a r n i n g n H a z a r d o u s pressure. See Annex AI.2.

7.5 Cell Electrolyte Solution--Dissolve 0.5 g of potassium iodide (KI) and 0.6 g of sodium azide (NAN3) in approximately 500 m L of high-purity water, add 5 mL of acetic acid (CH3COOH) and dilute to 1000 mL. NOTE 8--Bulk quantities of the electrolyteshould be stored in a dark bottle or in a dark place and be prepared fresh at least every 3 months. 7.6 Gas Regulators--Two-stage gas regulators must be used on the reactant and carrier gas. 7.7 Iodine (I2) , 20 mesh or less, for saturated reference electrode. NOTe 9: Warning--Toxic fumes. See AI.3. 7.8 Isooctane ~t (2,2,4-trimethyl pentane). NOTe 10 Warnlng--Combustible, very harmful. See Annex AI.4. NOTe 1l--The most reliable solvent is a sulfur-free form of the sample type to be analyzed. Alternatively, use a high-purity form of eyclohexane [boiling point 80"C (176"F)], iscoctane (2,2,4-trimethyl pentane) [boiling point, 99.3"C (21 I'F)], or hexadecane [boiling point, 287.5"C (549.5"F)]. 7.9 n-Butyl Sulfide (CH3CH2CH2CH2)2S. 7.10 Oxygen, high-purity grade (HP), 9 used as the reactant gas. NOTE 12: Warnlns---Oxygen accelerates combustion. See Annex AI.5.

7.1 1 Potassium Iodide (KI), fine granular. 7.12 Sodium Azide (NAN3), fine granular. NOTE 13: Warning--Highly toxic. Can react violently with shock, friction or heat.

7.13 Sulfur, Standard

NOTE 4--Since care should be taken not to overload the pyrolyzing capacity of the tube by too fast a sample injection rate, means should be provided for controlling the sample addition rate (0.1 to 0.2 ttL/s). 6.7 Sampling Syringe for GasmA gas syringe capable of delivering up to 5 cm 3 of gas sample into the pyrolysis furnace. A 25 mm by 28-gage needle should be attached to the syringe. 6.8 Exit Tube Insert, with quartz wool. 539

Solution

(approximately

30

9 Reagem Chemicals, American Chemical Society Spec~qcations, American Chemical Society, Washinston, De. For suggestions on the testing of reagents not listed by the American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.IC, and the United States Pharmacopeia and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), RockvilIe, MD. to High-purity grade gas has a minimum purity of 99.995 %. Jt A high purity isooctane of pesticide quality has been found satisfactory.

~

D 3246 TABLE 1 Typical Operational Conditions

mg/kg)--Pipet 10 m L of sulfur stock solution (reagent 7.14) into a 100-mL volumetric flask and dilute to volume with isooctane. NtyrE M--The analyst may choose other sulfur compounds for standards appropriate to sample boiling range and sulfur type which cover the concentration range of sulfur expected.

Reactant gas flow (oxygen), ctOl~n Carrier gas flow (At, He, N). cn~/mln

Fumace temperature; °C: Inlet zone Pyr~sle zone Outlet zone

"titrationcell

160 40

700 800 800 set to produce adequate mixing

Coulometer:

7.14 Sulfur, Standard Stock Solution (approximately 300 ppm (ttg/g))--Weigh accurately 0.5000 g of n-butyl sulfide into a tared 500-mL volumetric flask. Dilute to the mark with isooctane and reweigh. g of n-butyl sulfide × 0.2187 × 106 S, mg/kg ffi g of (n-butyl sulfide + solvent) (3)

Bias voltage, mV Gain

8. Sampling

8.1 Supply samples to the laboratory in high-pressure sample cylinders, obtained using the procedures described in Practice D 1265 and Practice F 307. 8.2 Because of the reactivity of most sulfur compounds, it has been found desirable to use TFE-fluorocarbon-coated cylinders or other specially treated sample containers. Test samples as soon as possible after receipt. 9. Preparation of Apparatus

9.1 Carefully insert the quartz pyrolysis tube in the pyrolysis furnace and connect the reactant and carrier gas lines. 9.2 Add the electrolyte solution to the titration cell and flush several times. Maintain an electrolyte level of '/s to 1/4 in. (3.2 to 6.4 ram) above the platinum electrodes. 9.3 Place the heating tape on the inlet of the titration cell. 9.4 Place an exit tube insert packed loosely with about 1 in. (25 ram) of quartz wool into the exit end of the pyrolysis tube. The quartz wool end of the exit tube should be in the hot zone of the pyrolysis tube. 9.5 Depending upon the instrumentation used, set up the titration cell to allow for adequate mixing of its contents and connect the cell inlet to the outlet end of the pyrolysis tube. Position the platinum foil electrodes (mounted on. the movable cell head) so that the gas inlet flow is parallel to the electrodes with the generator anode adjacent to the generator cathode. Assemble and connect the coulometer and recorder (integrator optional) as designed or in accordance with the manufacturer's instructions. Figure X I.2 illustrates the typical assembly and gas flow through a coulometric apparatus. 9.5.1 Turn the heating tape on. 9.6 Adjust the flow of the gases, the pyrolysis furnace temperature, titration cell, and the coulometer to the desired operating conditions. Typical operational conditions are given in Table 1.

160 low (approximately200)

metrically or by mass. The sample size should be 80 % or less of the syringe capacity. 10.3.1 Volumetric measurement can be obtained by filling the syringe with about 8 ~tL or less of sample, being careful to eliminate bubbles, retracting the plunger so that the lower liquid meniscus falls on the l-ttL mark, and recording the volume of liquid in the syringe. After the sample has been injected, again retract the plunger so that the lower liquid meniscus falls on the I-I~L mark, and record the volume of liquid in the syringe. The difference between the two volume readings is the volume of sample injected. 10.3.2 Alternatively, the sample injection device can be weighed before and after the injection to determine the amount of sample injected. This test method provides greater precision than the volume delivery method, provided a balance with a precision of +0.01 g is used. 10.4 Insert the syringe needle through the inlet septum up to the syringe barrel and inject the sample or standard at an even rate not to exceed 0.1 to 0.2 ttL/s. When a microlitre syringe is used with an automatic injection adapter, the injection rate (volume/pulse) should be calibrated to deliver 0.1 to 0.2 IIL/s. 10.5 Repeat the measurement of each calibration standard at least three times. NOTE 16--Not all of the sulfur in the sample comes through the furnace as titratable SO2. In the strongly oxidative conditions of the pyrolysistube some of the sulfur is also convertedto SO3 which does not react with the titrant. Accordingly,sulfur standards of n-butyl sulfidein isooctane or sulfur standards appropriate to sample boiling range and sulfur type and sulfur concentration should be prepared to guarantee adequate standardization. Recoveries less than 75 % are to be considered suspect. Low recoveries are an indication to the operator that he should check his parameters, his operating techniques, and his coulometric system. If the instrument is being operated properly, recoveries between 75 and 90 % are to be expected.

10.6 Calculate the percent sulfur found by the coulometer. For a 1-mV (span) recorder with a sensitivity of 0.1 mV/in, and a speed of 0.5 in./min: Sulfur recovered, % ffi [(,4 × 1.99)/(R × So × Vz/1000)] × 100 (4) where: A -- area, cm 2, R ffi coulometer range setting, t , So -- known concentration of sulfur in the standard blend, I~g/mL, and VL ffi volume standard blend charged, gL. 10.6.1 For a disk integrator: Sulfur recovered, %

10. Calibration and Standardization

10.1 Prepare a series of calibration standards covering the range of sulfur concentration expected. Follow instructions in 7.13, 7.14, or dilute to appropriate level with isooctane. 10.2 Adjust the operational parameters (9.5). NoTe 15--A ratio of 80 % oxygen to 20 % inert gas gives an acceptable recovery, and permits the use of a larger sample and a more rapid-charging rate.

[(C × 1.99 × 10-3)/(R ×

where:

10.3 The sample size can be determined either volu540

So

× V~I000)] × 100 (5)

~

D 3246 where: A -- area under curve, taking into account the area of the needle blank, in square centimetres using same range (fl) as calibration, W = weight of sample, g, and F = calibration factor, ttg S/cm 2 For gases:

C = 100 x number of integrator pen full scale excursions. Derivation of equations is given in Appendix X I. 10.6.2 For an electronic integrator: Sulfur Recovered, % = ~ A x loo (using consistent sample sizes)

(6)

where: A --- integrator result, mg/kg, and B - - - k n o w n concentration of sulfur in standard blend,

W=

mg/kg.

Vs×273×P×M (273 + C) × 760 × 22410

(9)

where:

NOTE 17--For further explanation of the derivation of the calculation, see Test Method D 3120.

10.7 If the fraction of sulfur converted to SO2 drops below 75 % of the standard solutions, fresh standards should be prepared. If a low conversion factor persists, procedural details should be reviewed. 10.8 Calculate the average calibration factor, F, Ixg S/cm 2, as follows: F = (SOx VzJlOOO)/A (7)

Vg

=

gas, c m 3

P = barometric pressure, mm Hg M = molecular weight of gas, g/tool, and C = temperature, gas, *C. For ethylene at 23"C and 760 mm Hg: W= Vsx 0.001154 For liquid: W= VzJl000 x d

(10)

(11)

where: VL = volume, ~tL, and d = density, g/mL.

11. Procedure 11.1 Place a silicone rubber septum in a bushing and connect to the valve on the sample cylinder containing the gaseous sample (for liquefied gas samples, see Note 5). Crack the cylinder valve so as to flush the air from all connections and then turn the bushing down to hold slight back pressure on the septum. Close the cylinder valve until the gas syringe is ready for filling.

13. Precision and Bias

13.1 The following criteria should be used for judging the acceptability of results: 13.1.1 Repeatability--The difference between successive test results, obtained by the same operator with the same apparatus under constant operating conditions on identical test material would, in the long run, and in the normal and correct operation of the test method, exceed the following values only in one case in twenty:

NOTE 18: WarningmSamples are extremely flammable. See Annex AI.7.

11.2 Crack the valve on the sample cylinder until slight flow of gas is detected around the septum. Insert the gas syringe in the septum carefully. NOTE 19: WarningmHigh pressure. See Annex AI.8. 11.3 Withdraw the plunger and allow the gas to flow through the syringe. After sufficient time to flush the syringe with sample, withdraw the plunger so as to contain no less than 5 cm 3 of gas. 11.4 Insert the tip of the needle barely through the septum. Inject 5.0 em 3 of gas into the instrument at a constant rate so that 15 s is required for the injection. Determine the sulfur concentration by the procedure described in 10.2 to 10.7. 11.5 Sulfur concentration can require adjustment of sample volume. 11.6 Report a needle blank with test results.

Range or Sample Type 0 to 10 mg/kg

Repeatability 0.4 mg/kg

13.1.2 Reproducibility--The difference between two single and independent results, obtained by different operators working in different laboratories on identical test material would, in the long run, and in the normal and correct operation of the test method, exceed the following values only in one case in twenty: Range or Sample Type 0to 10 mg/kg

Reproducibility 5 mg/kg

13.2 B i a s - - T h e bias of the procedure of this test method cannot be determined since an appropriate standard reference material containing trace sulfur level in ethylene is not available.

12. Calculation 12.1 Calculate the sulfur content of the sample in parts per million (ppm) by weight as follows: Sulfur, mg/kg = (A x F)/W (8)

14. Keywords

14.1 microcoulometer, oxidate microcoulometry; petroleum gas; pyrolysis furnace; sulfur; sulfur dioxide

541

~

D 3246 ANNEX

(Mandatory Information) A1. PRECAUTIONARY STATEMENTS Keep combustibles away from oxygen and eliminate ignition sources. Keep surfaces clean to prevent ignition or explosion, or both, on contact with oxygen. Always use a pressure regulator. Release regulator tension before opening cylinder valve. All equipment and containers used must be suitable and recommended for oxygen service. Never attempt to transfer oxygen from cylinder in which it is received to any other cylinder. Do not mix gases in cylinders. Do not drop cylinder. Make sure cylinder is secured at all times. Keep cylinder valve closed when not in use. Stand away from outlet when opening cylinder valve. For technical use only. Do not use for inhalation purposes. Keep cylinder out of sun and away from heat. Keep cylinders from corrosive environment. Do not use cylinder without label. Do not use dented or damaged cylinders. See Compressed Gas Association booklets G-4 and G-4.1 for details of safe practice in the use of oxygen.

AI.I Acetic Acid Warning--May produce severe burns to skin and eyes. Prolonged breathing of concentrated vapor may be harmful. Avoid contact with skin, eyes, and clothing. Use with adequate ventilation. AI.2 Compressed Gases Argon, Helium, Nitrogen Warning--Compressed gas under high pressure. Gas reduces oxygen available for breathing. Keep container closed. Use with adequate ventilation. Do not enter storage areas unless adequately ventilated. Always use a pressure regulator. Release regulator tension before opening cylinder. Do not transfer to cylinder other than one in which gas is received. Do not mix gases in cylinders. Do not drop cylinder. Make sure cylinder is supported at all times. Stand away from cylinder outlet when opening cylinder valve. Keep cylinder out of sun and away from heat. Keep cylinders from corrosive environment. Do not use cylinder without label. Do not use dented or damaged cylinders. For Technical Use only. Do not use for inhalation purposes.

AI.6 Sodium Azide WarningwHighly toxic. Inhalation may cause nausea, shortness of breath, dizziness, and headaches. Contact with dust may cause eye irritation. Avoid breathing dust or vapors from acidified solutions. Avoid contact with skin, eyes, and clothing. Wash thoroughly after handling.

A1.3 Iodine Warning--Fumes highly toxic. Can cause irritation and burning of eyes, nose, and throat. Avoid heating and prolonged breathing of vapors. Avoid contact with skin.

A1.7 Flammable Gas WarningwExtremely flammable (liquified) gas under pressure. Keep away from heat, sparks, and open flame. Use with adequate ventilation. Never drop cylinder. Make sure cylinder is supported at all times. Keep cylinder out of sun and away from heat. Always use a pressure regulator. Release regulator tension before opening cylinder. Do not transfer cylinder contents to another cylinder. Do not mix gases in cylinder.

A1.4 Isooctane Warning--Extremely flammable. Harmful if inhaled. Vapors may cause flash fire. Keep away from heat, sparks, and open flame. Keep container closed. Use with adequate ventilation. Avoid build-up of vapors and eliminate all sources of ignition, especially nonexplosion proof electrical apparatus and heaters. Avoid prolonged breathing of vapor or spray mist. Avoid prolonged or repeated skin contact.

A1.8 Flammable Gas Warning--Keep cylinder valve closed when not in use. Do not inhale. Do not enter storage areas unless adequately ventilated. Stand away from cylinder outlet when opening cylinder valve.

A1.5 Oxygen Warning--Oxygen vigorously accelerates combustion. Keep oil and grease away. Do not use oil or grease on regulators, gauges, or control equipment. Use only with equipment conditioned for oxygen service by careful cleaning to remove oil, grease, and other combustibles.

Keep cylinder from corrosive environment. Do not use cylinder without label. Do not use dented or damaged cylinders. For technical use only. Do not inhale. 542

II~) D 3246

APPENDIX ( N o n m a n d a t o r y Information)

Xl. DERIVATION O F C O U L O M E T R I C CALCULATIONS USED IN P A R A G R A P H 12.1 XI.3.1 The derivation of the equations used in the calculation section is based on the coulometric replacement of the triiodide (iodine) ions consumed in the microcoulometric titration cell reaction (13- ~ 31- + H+). The quantity of the reactant formed (triiodide ions) between the beginning and the interruption of current at the end of the titration is directly proportional to the net charge transferred,

X 1.1 The configuration of the pyrolysis tube and furnace may be constructed as is desirable as long as the operating parameters are met. Figure X I.I is typical of apparatus currently in use. X I.2 A typical assembly and oxidative gas flow through a coulometric apparatus for the determination of trace sulfur is shown in Fig. X 1.2. X 1.3 Derivation of Equations:

O. XI.3.2 In most applications a constant current is used so that the product of current, i, in amperes (coulombs per second), multiplied by the time, T (seconds), required to reach the end point provides a measure of the charge, Q (coulombs), necessary to generate the iodine equivalent to the reactant; that is, Q = it. Therefore, the number of equivalents o f reactant is equal to Q/F, where F is the Faraday constant, 95 500°C per equivalent. X1.3.3 Therefore, the expression to be solved to find the mass of reactant is:

Furnace Outlet

* t t t

:. '.-.-:

Center

Inlet

Reactant Gas l Oxygen --I~--

~

li::rl "

Carrier Argon

Gas

FIG. X1.1 Pyrolysis Tube

Q(C) x 16 g FC eq Concentration of sulfur--- mass of sulfur, g e'ff mass of sample, g = mass of sample, g 0.1 m__~V x 2 min x 60s x - - 1 0 -V 3 X 1 6 g x --106pg cm cm min ~" eq g 96 500*C A.s R (~) x ~ x x f) eq C

pg S = A cm 2 X

where: A cm 2 -- peak area measured in square inches, 0.1 mV/cm = millivolt span of upscale deflection for the recorder, 2 min/cm = chart speed in minutes per inch, = conversion of time in minutes to seconds, 60 s/min 10-3 V/mV = conversion of volts to millivolts, 16 g/eq = gram-equivalent of sulfur, 106 ttg/g -- micrograms per gram conversion factor, R (fl) = microcoulometer range switch setting in ohms, substituting V/R -- l(amps) A

0.1 m V cm 2 x

-

-

-

Q(a.s) F

= =

A. s/*C =

=

R(~)

recovery factor (ratio of p p m S determined in standard versus k n o w n p p m S in standard).

106 ttg A x 12x 10- 3 A . s x z - ~ x eq g ttgS = 96 500°C A . s R x - x ~ × f eq C Therefore, A x 12 × 10-3 × 16 x .!06 ~tg ~tg S = R × 96 500 x f

(xi.3)

(X1.4)

Therefore,

-

pg S = (A x 1.99)/(R x f )

(Xl.5)

Since ppm -- ~tg/g:

60s 10 -3 V . × ~

mm

(xl.2)

Therefore,

cm

cm

×

f

2 min x

(Xl.l)

mV

A × 1.99

ppm S =

96 500"C/eq Faraday's constant s (electrical equivalence of one gram-equivalent mass of any substance) conversion of coulombs to ampere-seconds, and

R x f x volume, ~tL x 10-3 mL x density, I~L mL A x 1.99 x 103 ppm S --

543

R ×f×

volume × density

(xL6)

(xi.7)

~

D 3246

Inlet Outlet Zone Zone Sample ArgonSepturn Injection ~ I~_.i~. ~ V ~Py //~/ ~o1~: / /is,~ / / / ~A - ~Ii_1,_~

l

Microcoulometer

/

Titration Cell Potentiometric Recorder

FIG. Xl.2 FlowDiagramfor CoulometricApparatusfor TraceSulfurDetermination Then:

Since m a s s = v o l u m e x density

ppm S ffi (,4 x 1.99)/(R x F x mass, g)

(Xl.8) ppm S =

XI.3.4 Derivation with Disk Integrator--A in Eq XI.5 is expressed as in. 2 However, it may also be expressed as

(Xl.10)

R x volume, ~tL x density, ~LL x f

counts. Therefore, A in. 2 = c o u n t s x l 0 -3 s i n c e 1 in. 2 = 1000 counts. Therefore, substituting counts x l 0 -3 for A in Eq 5

p p m S = ( c o u n t s x 1.99 x 10-3)/(R x mass, g x f )

~ve$

I~g S = (counts x 1.99 x 10-3)/(R x]~

counts x 1.99

NOTE Xl.I---Counts = 100 x number of integrator per full-scale excursions.

(XI.9)

asserted

The American Society for Testing and Materials takes no position respecting the validity of any patent rights in connection with any item mentioned in thi~ standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reepproved or withdrawn, Your comments are invited either for revision of this etar~ard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful ¢onaldoratlon at a meeting of the responsible technical committee, which you may attend, ff you feel that your <,'omments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 100 Barr Harbor Drive, West Conshohocken, PA 19428.

544

(~)

Designation: D 3279 - 90 Standard Test Method for n-Heptane Insolubles 1 This standard is issued under the fixed designation D 3279; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last re,approval. A superscript epsilon (~) indicates an editorial change since the last revision or reapproval.

1. Scope 1.1 This test method covers determination of the weight percent of asphaltenes as defined by insolubility in normalheptane solvent. It is applicable to all solid and semi-solid petroleum asphalts containing little or no mineral matter, to gas oils, to heavy fuel oils, and to crude petroleum that has been topped to a cut-point of 650"F (343"C) or higher. 1.2 This standard does not purport to address all of the safety problems associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. See Section 7 for a specific hazard statement.

5.1.5 Filter Flask, heavy-wall with side tube, 500-mL capacity. 5.1.6 Filter Tube, 40 to 42 mm in inside diameter. 5.1.7 Rubber Tubing or adapter for holding Gooch crucible on the filter tube. NOtE 1 - - O t h e r suitable assemblies permitting vacuum filtration with a Gooch crucible may be used.

6. Solvent 6.1 n-Heptane, 99.0 minimum mol % (Pure Grade). 7. Hazards 7.1 n-Heptane has a boiling point of 209"F (98"C) and a flash point of 30*F ( - l ' C ) , which means that it should be handled with care. It is recommended that both the reflux dispersion and filtration steps be conducted in a ventilated hood and away from flames or other sources of heat.

2. Referenced Document

2.1 ASTM Standard." C 670 Practice for Preparing Precision and Bias Statements for Test Methods for Construction Materials 2

8. Procedure 8.1 Into the 250-mL Edenmeyer flask, weigh to the nearest 0.1 m g a quantity of the sample to be tested, using 0.5 to 0.6 g for airblown asphalts, 0.7 to 0.8 g for asphalt paving binders and crude residues, and 1.0 to 1.2 g for gas oils and heavy fuel oils (Note 2). Add n-heptane in the ratio 100 mL of solvent per 1 g of sample, using proportionally less or more solvent as dependent upon the sample size. Unless the asphalt is in a granular form, heat the flask gently and turn it to cause the sample to be distributed somewhat over the bottom or lower sides of the flask.

3. Summary of Test Method 3.1 The sample is dispersed in n-heptane and filtered through a glass-fiber pad. The insoluble material is washed, dried, and weighed. 4. Significance and Use 4.1 This test method is useful in quantifying the asphaltene content of petroleum asphalts, gas oils, heavy fuel oils, and crude petroleum. Asphaltene content is defined as those components not soluble in n-heptane.

NOTE 2 - - T e s t s show a small a m o u n t of insolubles (-+0.3 weight %) remain on walls of the precipitation flask despite repeated washings.

5. Apparatus and Materials 5.1 The assembly of the dispersing apparatus is illustrated in Fig. 1 with details of the component parts as follows: 5.1.1 Erlenmeyer Flask of 250-mL capacity adapted to an Allihn-type reflux condenser, each with a 35/25 ball joint. 5.1.2 Magnetic Stirrer and Magnetic-Stirrer Hot Plate equipped with a voltage regulator. 5.1.3 Gooch Crucible, glazed inside and outside with the exception of the outside bottom surface. The approximate dimensions shall be a diameter of 44 mm at the top tapering to 36 mm at the bottom and a depth of 28 ram. 5.1.4 Filter Pad, glass-fiber 32 mm in diameter)

When expected level of n-C7 insolubles is 6 % or less, use of a tared 250-mL Erlenmeyerflaskis recommended.After all possible precipitate has been washed from the flask to the filteringcrucible in 8.3, include the flask with the crucible for the drying, weighing, and calculation procedures in 8.3 and 9.1. 8.2 Place the Erlenmeyer flask, containing the sample plus solvent with magnetic stirrer added, on the magnetic-stirrer hot plate and secure under the reflux condenser. With the magnetic stirrer in operation adjust for gentle refluxing for a period of 15 to 20 min when testing paving binders, fuel oils, gas oils, or crude residues. For airblown asphalts, a reflux period of 25 to 30 min is recommended. In all cases, allow the dispersed mixture to cool to room temperature for a period of 1 h. 8.3 Place the Gooch crucible plus one thickness of the glass-fiber fdter pad in an oven at about 225"F (1070C) for 15 min, allow to cool in a desiccator, and then weigh to the nearest 0.1 mg. Set up the filtering crucible plus filter pad in the suction flask and pre-wet with 5 mL of n-heptane (see Fig. 2). Warm the flask containing the sample plus solvent to

1 This test method is under the jurisdiction of ASTM Committee D-4 on Road and Paving Materials and is the direct responsibility of Subcommittee D04.47 on Miscellaneous Asphalt Tests. Current edition approved Oct. 26, 1990. Published December 1990. Originally published as D 3279 - 73 T. Last previous edition D 3279 - 83. 2 Annual Book of A S T M Standards, Vol 04.02. 3 Glass filter pads No. 934-AH (Huribut) may be purchased from Reeve Angel and Company, Clifton, NJ.

545

~ ) D 3279 100 to 120°F (38 to 49°C) on the hot plate and pour its contents (except for the magnetic stirrer) through the filter using a gentle vacuum. Filtration will proceed most rapidly if the supernatant liquid is filtered first with the insolubles transferred to the filter last. Police the beaker or flask while transferring the final precipitate, using either a rubber policeman or stainless steel spatula with a squared end. Wash the precipitate with three portions of n-heptane of about 10 mL each, first rinsing out the flask therewith. Place the crucible in the 225°F oven for a period of 15 rain, cool in a desiccator, and weigh.

9. Calculation and Report 9.1 Calculate the weight percent of normal-heptane insolubles (NHI) as the percentage by weight of the original sample as follows: NHI, % = (A/B) x 100 where: A = total weight of insolubles, and B = total weight of sample. For percentages of insolubles less than 1.0, report to the nearest 0.01%; for percentages of insolubles of 1.0 or more, report to the nearest 0. 1%.

il

10. Precision and Bias 10.1 Precision of the method has been determined as follows:

Single-operator Multilaboratory

Standard Deviation~

Acceptable Range of Two Results"4

0.53 % NHI 0.93 % NHI

1.51% NHI 2.78 % NHI

,4 These numbers represent, respectively, the (IS) and (D2S) limits as described in Practice C 670. The precision is for samples covering a range from 4.0 to 29.0 % HI.

FIG. 1

DispersingApparatus

546

lip D 3279

/

\ %

FIG. 2

Filtration Apparatus

The American Society for Testing and Materials takes no position respecting the vafidity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibifity. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103.

547

Designati°n: D 3524 - 90 1

An American National Standard

Standard Test Method for Diesel Fuel Diluent in Used Diesel Engine Oils by Gas Chromatography 1 This standard is issued under the fixed designation D 3524; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (0 indicates an editorial change since the last revision or reapproval. ~' NoTE--Section 5 was corrected editorially in October 1991.

1. Scope 1.1 This test method covers the determination of diesel fuel as a contaminant in used lubricating oil. The method is limited to SAE 30 oil.

introduced into a gas chromatographic column which separates hydrocarbons in boiling point order. The column temperature is raised at a reproducible rate and the resulting chromatogram is interpreted for diesel fuel dilution.

NOTE l - - T h i s test m e t h o d m a y be applicable to higher viscosity grade oils. However, such oils were not included in the program used to develop the precision statement.

4. Significance and Use 4.1 Some fuel dilution of the engine oil may take place during normal operation. However, excessive fuel dilution is of concern in terms of possible performance problems.

1.2 There is some overlap of the boiling ranges of diesel fuel and SAE 30 engine oils. Moreover, the boiling range of SAE 30 oils from various sources can vary appreciably. As a result, the calibration can be altered by as much as 2 %, in terms of fuel dilution. When testing unknown or mixed brands of used engine oil, it should be realized that the precision of the method may be poorer than the precision obtained when calibrating with a new oil representative of the used oil being tested. 1.3 The values stated in SI units are to be regarded as the standard. The values stated in inch-pound units are for information only. 1.4 This standard does not purport to address all of the

5. Apparatus 5.1 Gas Chromatograph--Any gas chromatograph can be used that has the following performance characteristics: 5.1.1 DetectorDEither a thermal conductivity or flame ionization detector can be used. The detector must have sufficient sensitivity to detect 1.0 % decane with a peak height of at least 10 % of full scale on the recorder under the conditions prescribed in this method, and without loss of resolution as defined in 7.1.3. The detector also must be capable of operating continuously at a temperature equivalent to the maximum column temperature employed, and it must be connected to the column so as to avoid any cold spots. Under the conditions described for the method, the drift should not be more than 1% of full scale per hour. 5.1.2 Column Temperature Programmer--The chromatograph must be capable of program temperature operation over a range sufficient to establish a retention time of at least 1 min for the initial peak(s) and to elute the entire sample. The programming rate must be sufficiently reproducible to obtain retention time repeatability of 0.1 min for each component in the calibration mixture (6.4). 5.1.3 Sample Inlet System--The sample inlet system must be capable of operating continuously at a temperature equivalent to the maximum column temperature employed, or provide on-column injection with some means of programming the entire column, including point of sample introduction up to the maximum temperature required. The sample inlet system must be connected to the chromatographic column so as to avoid any cold spots. 5.2 RecordermA recording potentiometer with a full-scale response time of 2 s or less must be used. Ifa manual method of area measurement, such as a planimeter, is employed, the chart speed must be at least 152 cm/h (60 in./h) to minimize errors in peak area measurements. This requirement is waived if a ball-and-disc integrator or an electronic integrator is employed. 5.3 ColumnmAny column and conditions may be used,

safety problems associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 2. Terminology

2.1 Description of Term Specific to This Standard: 2.1.1 fuel dilutionDthe amount, expressed as a percentage, of engine fuel found in engine lubricating oil. This may be the result of engine wear or improper performance. 2.2 Abbreviations: 2.2.1 A common abbreviation of hydrocarbon compounds is to designate the number of carbon atoms in the compound. A prefix is used to indicate the carbon chain form, while a subscripted suffix denotes the number of carbon atoms. For example: normal decane n-C~o iso-tetradecane i-C14 3. Summary of Test Method 3.1 A mixture of n-decane and used lubricating oil is This test method is under the jurisdiction of ASTM Committe D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.04 on Hydrocarbon Analysis. Current edition approved Oct. 26, 1990. Published December 1990. Originally published as D 3524 - 76. Last previous edition D 3524 - 86.

548

~)

D 3524

provided, under the conditions of the test, separations are in order of boiling points and the column resolution, R, is at least 3 and not more than 5 (7.1.3). Since a stable baseline is an essential requirement of this method, matching dual columns are required to compensate for column bleed, which cannot be eliminated completely by conditioning alone. 5.4 Integrator--Means must be provided for determining the accumulated area under the chromatogram. This can be done manually by means of a polar planimeter. Mechanical means, such as the disc integrator, may be used also. However, best precision and automatic operation can be achieved with electronic integration. 5.5 Flow Controllers--Chromatographs using thermal conductivity detectors also must be equipped with constantflow controllers capable of holding carder gas flow constant to _+1% over the full operating temperature range. 5.6 Sample Device: 5.6.1 Micro Syringe--A micro syringe, usually 10 ~tL, is used for sample introduction. 5.6.2 Automatic sampling devices or other sampling means, such as indium encapsulation, may be used, provided the system can be operated at a temperature sufficiently high to vaporize completely hydrocarbons with an atmospheric boiling point of 538"C (1000*F), and the sampling system is connected to the chromatographic column so as to avoid any cold spots. 5.7 Vial, 15-mL, screw cap.

6. Reagent and Material 6.1 Liquid Phase for Columns--See Note 2. NOTE 2--The followingmaterials have been used successfullyas liquid phases: Silicone Gum Rubber UC-W982 Silicone Gum Rubber GE-SE-303 Silicone Gum Rubber OV-14 Silicone Gum Rubber OV-1014 6.2 Solid Support--Usually crushed fire brick or diatomaceous earth. Sieve size and support loading should be such as will give optimum resolution and analysis time. In general, support loadings of 3 to 10 % have been found most satisfactory. 6.3 Carrier GasmHelium (Warning--See Note 3.) or hydrogen (Warning--See Note 4) for use with thermal conductivity detectors; or nitrogen, (Warning--See Note 3.) helium, or argon for use with flame ionization detectors. 6.4 Calibration Mixtures--A minimum of three mixtures of diesel fuel and lubricating oil (Warning--See Note 5.) of a similar type to that being analyzed are prepared to cover the range from 0 to 12 weight% (mass%) diesel fuel, calculated as follows: Diesel fuel, wt% (mass %) weight (mass) of fuel = weight (mass) of fuel and oil x 100 (1) NOTE 3: Warning--Argon, helium, and nitrogen are compressed gases under pressure.

NOTE 4: Warning--Hydrogenis an extremelyflammablegas under pressure.

NOT~ 5: Warning--Combustiblefiquid. 6.5 n-Decane, 99 % pure. (Warning--See Note 6.) NoTE 6: Warning---Combustible,vapor harmful.

7. Preparation of Apparatus

7.1 Column Preparation--Any satisfactory method used in the practice of the gas chromatography that will produce a column meeting the requirements of 5.3 may be used. The column must be conditioned at the maximum operating temperature until baseline shift due to column bleeding has been reduced to a minimum. 7.1.1 The column can be conditioned very rapidly and effectively by the following procedure: 7.1.1.1 Disconnect the column from the detector. 7.1.1.2 Purge the column thoroughly at ambient temperature with carder gas. 7.1.1.3 Turn off the carrier gas and allow the column to depressurize completely. 7.1.1.4 Raise the column temperature to the maximum operating temperature and hold at this temperature for at least 1 h with no flow through the column. 7.1.1.5 Cool the column to at least 100*C before turning on carder gas again. 7.1.1.6 Program the column temperature up to the maximum several times with normal carder gas flow. The column then should be ready for use. 7.1.2 An alternative method of column conditioning, which has been found effective for columns with an initial loading of I 0 % liquid phase, consists of purging the column with carder gas at the normal flow rate while holding the column at maximum operating temperature for 12 to 16 h. 7.1.3 Column Resolution--To test column resolution use Fig. 1 and calculate the resolution, R, from the distance between the C~6 and Cts n-paraffin peaks at the peak maxima, d, and the width of the peaks at the baseline, Y~ and Y2, as follows: R = [2(di - d2)]/Y, + }'2

Resolution, R, using the above equation, must be at least 3 and not more than 5. 7.2 Chromatograph--Place in service in accordance with the manufacturer's instructions. Typical operating conditions are shown in Table 1. 7.2.1 If a flame ionization detector is used, the deposits dl,

mm

d2, m m

m

Hexadecane

"5

Octadecane

E 0

: Registered trademark of Union Carbide Corp. 3 Registered trademark of General Electric Co. 4 Registered trademark of Ohio Valley Specialty Chemicals Co.

H Y2, m m

Ylo

mm

FIG. 1. ColumnResolution

549

(2)

~ TABLE 1

D 3524

Typical Operating Conditions

Column length, m (ft) Column outside diameter, mm (in.) Liquid phase Support material Treatment Mesh size Column temperature, initial, °C Column temperature, final, °C Programming rate, °C/min Detector Detector temperature, *C Injection port temperature, *C Sample size, pL Flow rate, cm~/min

the total areas due to decane and to the fuel portion in each mixture. 10.1.1 There can be an overlap between the diesel fuel and lube oil peaks. Using a chromatogram of one of the calibration mixtures, select the retention time of the minimum overlap. Use this retention time as the end of the area due to the diesel fuel for all subsequent analyses. See Fig. 2 for a typical chromatogram. 10.2 Determine the ratio, R, for each standard as follows: R AIB (3) where: A -- total area due to diesel fuel peaks, and B = area due to n-decane. 10.3 Plot a calibration curve relating R to the weight percent of diesel fuel.

0.610 (3) 3.2 (1/8) Silicone gum rubber OV-101 A Chromosorb W B acid washed, silanized 80/100 70 325 16 FID c 350 300 1 30

=

A Registered trademark of Ohio Valley Specialty Chemical Co. a Registered trademark of Johns-Manville Products Corp. c Flame ionization detector.

formed in the detector from combustion of the silicone rubber decomposition products must be removed regularly, since they change the response characteristics of the detector. 7.2.2 If the sample inlet system is heated above 300"C, a blank run must be made after new septums are installed, to check for extraneous peaks produced by septum bleed. At the sensitivity levels commonly employed in this method, conditioning of the septum at the operating temperature of the sample inlet system for several hours will minimize this problem. Recommended practice is to change septums at the end of the day's operation rather than at the beginning.

11. Calculation 11.1 Record the total areas due to the fuel portion of the sample and the area due to decane as described in 10.1 and determine the ratio, R, as described in 10.2. 11.2 Determine the weight percent (mass percent) of diesel fuel of the samples by relating the R values obtained to the previously determined calibration curve. Report the results to nearest 0.1%. 12. Precision and Bias 12.1 The following criteria should be used for judging the acceptability of results (95 % probability): 12.1.1 Repeatability--The difference between successive test results, obtained by the same operator with the same apparatus under constant operating conditions on identical test material, would, in the long run, in the normal and correct operation of the test method, exceed the following value only in one case in twenty: 0.3 weight (mass %) 12.1.2 Reproducibility--Tbe difference between two, single and independent results, obtained by different operatots working in different laboratories on identical test material, would, in the long run, in the normal and correct operation of the test method, exceed the following value only one case in twenty:

8. Preparation of Sample 8.1 Weigh 1.0 ___0.01 g of decane (Warning--see Note 6) into a 15-mL vial. Shake the sample in the delivered bottle and add 10.00 ___0.01 g of sample to the vial (Warning--see Note 5). Cap and mix well.

9. Procedure 9.1 Program the column temperature upward to a temperature sufficiently high to elute all the components from the column. Following a rigorously standardized procedure, cool the column down to the starting temperature and, at the exact time set by the schedule, inject a carefully measured volume of sample (1 laL). Start programming the column temperature upward at a rate that will produce the desired separations as specified in 5.3. Turn on the recorder chart drive and integrator immediately after injecting the sample. Record the peaks at a sensitivity setting that allows the maximum peak height compatible with the method of measurement being used. 9.2 Since complete resolution of sample peaks is not expected, the sensitivity setting should not be changed during the test. If a ball-and-disc integrator or manual means are used for measuring peak areas, the sensitivity setting must be such that the maximum peak of the fuel portion of the chromatograph remains on the scale of the recorder.

t-

.o

"3o

==

_¢

o•

ieselFuel

10. Calibration

I0.1 Run each of the calibration mixtures (6.4) by the procedure described in Sections 8 and 9, injecting approximately the same volume as chosen for the sample. Record

I

I

I

I

I

0

2

4

6

8

FIG. 2.

550

I-

I

I

10 12 Minutes

I

I

I

I

14

16

18

20

Typical Chromatogram

o 3s24 1.6 weight

12.2 BiasmNo estimate of the bias of this test method is possible because of the empirical nature of this test method.

(mass %)

NOTE 7 - - T h e above precision is based on the use of electronic integrators to measure areas and may not be indicative when other means of measurement are used. NOTE 8--This precision statement applies only to SAE 30 oils.

13. Keywords 13.1 diesel fuel; fuel dilution; gas chromatography; lubricating oil

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and ff not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend, ff you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103.

551

q~]~

Designation: D 3606 - 96

An AmericanNationalStandard

Standard Test Method for Determination of Benzene and Toluene in Finished Motor and Aviation Gasoline by Gas Chromatography 1 This standard is issued under the fixed designation D 3606; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (e) indicates an editorial change since the last revision or reapproval.

TABLE 1 InstrumentParameters

1. Scope 1.1 This test method provides for the determination of benzene and toluene in finished motor and aviation gasolines by gas chromatography. 1.2 Benzene can be determined between the levels of 0.1 and 5 volume % and toluene can be determined between the levels of 2 and 20 volume %. 1.3 The precision for this test method was determined using conventional gasoline as well as gasolines containing oxygenates (ethers such as methyl tert-butyl ether, ethyl tert-butylether and tert-amylmethylether). 1.4 It has been determined that this test method is not applicable to gasolines containing ethanol. Methanol may also cause interference. 1.5 The values stated in SI units are to be regarded as the standard. Values given in parentheses are provided for information only. 1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements, see Notes 1 through 11.

Detector Columns: Length, m Outside diameter, mm Stationary phase

Support Reference column Temperature: Sample inlet system, °C Detector, °C Column, *C Carder Gas: Linear Gas Rate, cm/s Volume flow rate, ctrP/mln Column head pressure, kPe (l:ml) Recorder range, mV Chart speed, cm/mln Sample size, pL Total cyck) time, rain Back flush, mln

thermal conductivity two, stainless ste~ (A) 0.8; (B) 4.6 3.2 (A) methyl silicone, 10 mass (B) TCEP, 20 nmss Y~

(A) Chroncsom W, 60 to S0-mesh (B) Chromosodo P, 80 to 100-mesh Any column or restriction may be used. 200 200 145 helium 6 approx 30 approx 200 (30) 0 to 1 1 2 8 approx 0.75 A

A This beck flush time must be determined for each column system.

are detected by a thermal conductivity detector and recorded on a strip chart. The peak areas are measured, and the concentration of each component is calculated with reference to the internal standard.

2. Referenced Documents

2.1 A S T M Standards: D 4057 Practice for Manual Sampling of Petroleum and Petroleum Products 2

4. Significance and Use 4.1 Benzene is classed as a toxic material. A knowledge of the concentration of this compound can be an aid in evaluating the possible health hazard to persons handling and using the gasoline. This test method is not intended to evaluate such hazards.

3. Summary of Test Method 3.1 An internal standard, methyl ethyl ketone (MEK), is added to the sample which is then introduced into a gas chromatograph equipped with two columns connected in series. The sample passes first through a column packed with a nenpolar phase such as methyl silicone (8.1.1) which separates the components according to boiling point. After octane has eluted, the flow through the nonpolar column is reversed, flushing out the components heavier than octane. The octane and lighter components then pass through a column packed with a highly polar phase such as 1,2,3tris(2-cyanoethoxy) propane (8.1.2) which separates the aromatic and nonaromatic compounds. The eluted components

5. Apparatus 5.1 Chromatograph--Any chromatographic instrument that has a bacldlush system and thermal conductivity detector, and that can be operated at the conditions given in Table 1, can be employed. Two backflush systems are shown. Figure 1 is a pressure system and Fig. 2 is a switching valve system. Either one can be used. The detector-recorder combination must produce a 4-ram deflection for a 2-pL sample containing 0.1 volume % MEK when operated at maximum sensitivity. 5.2 Columns--One 0.8-m (2.5-ft) length of 3.2-mm (I/8-in.) outside diameter stainless steel tubing and one 4.6-m (15-ft) length of 3.2-ram outsider diameter stainless steel tubing are used. 5.3 Recorder, strip chart. A 0 to l-mV range recording

* This method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D 02.04 on Hydrocarbon Analysis. Current edition approved Nov. 10, 1996. Published January 1997. Originally published as D 3606 - 77. Last previous edition D 3606 - 92. 2 Annual Book of ASTM Standards, Vo105.02.

552

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FIG. 1 Pressure Baokflush

5.8 Vacuum Source. 5.9 Evaporator, vacuum, rotary. 5.10 Flask, boiling, round-bottom, short-neck, with 24/4oT joint, 500-mL capacity. Suitable for use with evaporator (5.9). 5. l I Lamp, infrared. 5.12 Burets, automatic, with integral reservoir, 25-mL caoacity.

potentiometer with a response time of 2 s or less and a maximum noise level of +0.3 % of full scale is recommended. 5.4 Microsyringe, 5-pL capacity. 5.5 Pipets, volumetric, 1 and 2-mL, calibrated in 0.01 mL; 5, 10, and 20-mL capacity. 5.6 Flasks, volumetric, 25 and 100-mL capacity. 5.7 Vibrator, electric. 553

~

D 3606 8.1.1 Methyl Silicone Packing--Weigh 45 g of the Chromosorb W and pour into the 500-mL flask (5.10). Dissolve 5 g of the methyl silicone in approximately 50 mL of chloroform. (Warning--See Note 3) Pour the methyl siliconechloroform solution into the flask containing the Chromosorb W. Attach the flask to the evaporator (5.9), connect the vacuum, and start the motor. Turn on the infrared lamp and allow the packing to mix thoroughly until dry. 8.1.2 1,2,3-Tris(2-cyanoethoxy) Propane (TCEP) Packing--Weigh 80 g of Chromosorb P and pour into the 500-mL flask (5.10). Dissolve 20 g of TCEP in 200 mL of methanol and pour into the flask containing the Chromosorb P. Attach the flask to the evaporator (5.9), connect the vacuum, and start the motor. Turn on the infrared lamp and allow the packing to mix thoroughly until dry. (Do not heat the packing over 180"C.)

6. Materials

6.1 Carrier Gas--Helium, 99.99 % pure. (Warning--See Note 1) NOTE 1: Warning--Compressedgas under high pressure. 6.2 Support--Crushed firebrick, 3 acid-washed, 60 to 80mesh and 80 to 100-mesh. 6.3 Liquid Phases--l,2,3-Tris(2-cyanoethoxy) propane (TCEP) and methyl silicone. 4 6.4 Solvents: 6.4.1 Methanol, reagent grade. (Warning--See Note 2) NOTE 2: Warning--Flammable. Vapor harmful. Can be fatal or cause blindnessif swallowedor inhaled. 6.4.2 Chloroform, reagent grade. (Warning--See Note 3) NOTE 3: Warning--Canbe fatal if swallowed.Harmfulif inhaled. 6.4.3 Methylene Chloride, for cleaning columns. (Warning-See Note 4) NOTE 4" Warning--Harmful if inhaled. High concentrations can cause unconsciousnessor death.

9. Preparation of Column

9.1 Cleaning Column--Clean the stainless steel tubing as follows. Attach a metal funnel to one end of the steel tubing. Hold or mount the stainless steel tubing in an upright position and place a drain beaker under the outlet end of the tubing. Pour about 50 mL of methylene chloride (Warning-See Note 4) into the funnel and allow it to drain through the steel tubing and into the drain beaker. Repeat the washing procedure with 50 mL of acetone. (Warning-See Note 5) Remove the funnel and attach the steel tubing to an air line, using vinyl tubing to make the connection. Remove all solvent from the steel tubing by blowing filtered, oil-free air through or pulling a vacuum. 9.2 Packing Columns--Preform Columns A and B separately to fit the chromatograph. Pack the 0.8-m tubing (Column A) with the methyl silicone packing (8.1.1) and the 4.6-m tubing (Column B) with the TCEP packing (8.1.2) using the following procedure. Close one end of each tubing with a small, glass wool plug, and connect this end to a vacuum source by means of a glass wool-packed tube. To the other end connect a small polyethylene funnel by means of a short length of vinyl tubing. Start the vacuum and pour the appropriate packing into the funnel until the column is full. While filling each column, vibrate the column with the electric vibrator to settle the packing. Remove the funnel and shut offthe vacuum source. Remove the top 6 mm ('/4-in.) of packing and insert a glass wool plug in this end of the column.

6.4.4 Acetone, for cleaning columns. (Warning--See Note 5) NOTE 5: Warning--Extremelyflammable. Vapors can cause flash fires.

6.5 Internal Standard: 6.5.1 Methyl Ethyl Ketone (MEK), 99.9 % pure. (Warning--See Note 6) NOTE 6: Warning--Flammable.Vapor can be harmful. 6.6 Calibration Standards: 6.6.1 Benzene, 99 + mol %. (Warning--See Note 7) NOTE 7: Warning--Poison. Carcinogen. Harmful or fatal if swallowed. Extremelyflammable.Vapors can cause flash fires. 6.6.2 lsooctane, 99 + tool %. (Warning--See Note 8) NOTE 8: Warning--Extremelyflammable.Harmful if inhaled. 6.6.3 Toluene. (Warning--See Note 9) NOTE 9: Warning--Flammable.Vapor harmful. 6.6.4 n-Nonane, 99 + mol %. (Warning--See Note 10) NOTE 10: Warning--Flammable.Vapor harmful. 7. Sampling 7.1 Gasoline. (Warning--See Note 11) Samples to be analyzed by this test method shall be obtained using the procedures outlined in Practice D 4057. NoTE I1: WarningmExtremelyflammable. Vapors harmful if inhaled.

10. Configuration of Apparatus and Establishment of Conditions

10.1 Conditioning Column--Install Columns A and B as shown in Fig. 1 or Fig. 2 in accordance with the system preferred (5.1). Do not connect the exit end of Column B to the detector until the columns have been conditioned. Pass helium gas through the column at approximately 40 cm3/ min. Condition the column at the listed temperatures for the specified time periods.

8. Preparation of Column Packings 8.1 Prepare two packing materials (one packing material consists of 10 mass % methyl silicone on Chromosorb W; the other, 20 mass % TCEP on Chromosorb P) in accordance with the following procedures: 3 Chmmosorb P (80 to 100-mesh) and Chromosorb W (60 to 80-mesh) from Johns-Manville Co., Philadelphia, PA, have been found satisfactory for this purpose. 4 TCEP from Applied Science Laboratories, Inc., P.O. Box 440, State College, PA 16801, and OV 101 from Ohio Valley Specialty Chemicals Inc., Rt. 6, Brant Drive, Marietta, OH 45750, have been found satisfactory for this purpose.

Temperature, "(2

Hours at Temperature

50 100 150 170

I/2 Ih I

3

10.2 Assembly--Connect the outlet of Column B to the 554

O o 36o6 A. PIPING AND INSTRUMENTATION A

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sample side. Observe the pressure on gage G¢. 10.3.1.2 Close Tap A and open B and C. The pressure reading on gage GA should fall to zero immediately. If not, open the needle valve until the pressure falls to zero. 10.3.1.3 Close Tap B. Adjust the secondary pressure regulator until the reading of gage Gc is 3.5 to 7 kPa (0.5 to 1 psi) higher than observed in 10.3.1.1. 10.3.1.4 Open Tap B and adjust the backflush vent control needle valve until the pressure recorded on GA approximates a gage pressure of 14 to 28 kPa (2 to 4 psi).

detector port. Adjust the operating conditions to those listed in Table 1, but do not turn on the detector circuits. Check the systems for leaks. 10.3 Flow Rate Adjustment: 10.3.1 Column System Setup for Pressure Backflushing

(Fig. 1): 10.3.1.1 Open Tap A and B and close C; set the primary pressure regulator to give the desired flow (Table 1) through the column system (at an approximate gage pressure of 205 kPa (30 psi)). Measure the flow rate at the detector vent, 555

~) D 3606 10.3.1.5 Forward Flow--Open Taps A and C and close Tap B (Fig. 1 B 1). 10.3.1.6 Backflush--Close Tap A and open Tap B. (There should be no baseline shift on switching from forwardflow to backflush. If there is a baseline shift increase the secondary pressure slightly.) (Fig. 1) 10.3.2 Column System Setup for ValveBackflushing (Fig.

2): 10.3.2.1 Set the valve in the forwardflow mode (Fig. 2 B 1), and adjust flow control A to give the desired flow (Table 1). Measure the flow rate at the detector vent, sample side. 10.3.2.2 Set the valve in the backflush position (Fig. 2 B 2), measure the flow rate at the detector vent, sample side. If the flow has changed, adjust flow control B to obtain the correct flow. (Flows should match to within +-1 cma/min). 10.3.2.3 Change the valve from forward flow to the backflush position several times and observe the baseline. There should be no baseline shift or drift after the initial valve kick that results from the pressure surge. If there is a baseline shift, increase or decrease flow control B slightly to balance the baseline. (A persistent drift could indicate leaks somewhere in the system.) 10.4 Determine Time to Backflush--The time to backflush will vary for each column system and must be determined experimentally as follows. Prepare a mixture of 5 volume % isooctane in n-nonane. Using the injection technique described in 11.4 and with the preferred system (10.3) in the forwardflow mode, inject 1 pL of the isooctane - n-nonane mixture. Allow the chromatogram to run until the n-nonane has eluted and the recorder pen has returned to baseline. Measure the time in seconds, from the injection until the recorder pen returns to baseline between the isooctane and n-nonane peaks. At this point all of the isooctane, but essentially none of the n-nonane, should have eluted. One half of the time determined should approximate the "time to backflush" and should be from 30 to 60 s. Repeat the run, including the injection, but switching the system to the backflush mode at the predetermined "time to backflush." This should result in a chromatogram of isooctane with little or no n-nonane visible. If necessary, make additional runs, adjusting the "time to backflush" until this condition of all the isooctane and little or no n-nonane is attained. The "time to backflush" so established, including the actual valve operations, must be used in all subsequent calibrations and analyses.

11.2 Calibration Blends--Accurately measure 1.0 mL of MEK into a 25-mL volumetric flask, and fill to the mark with the first standard sample (11.1). Continue doing this until all blends have been prepared. 11.3 ChromatographicAnalysis--Chromatograph each of the calibration blends using the conditions established in 10.4 using the following injection technique: 11.4 Injection of Sample--Flush the 5-pL microsyringe at least three times with the sample mixture and then fill with about 3 pL of the sample. (Avoid including any air bubbles in the syringe.) Slowly eject the sample until 2.0 ~tL remains in the syringe; wipe the needle with tissue and draw back the plunger to admit 1 to 2 pL of air into the syringe. Insert the needle of the syringe through the septum cap of the chromatograph and push until the barrel of the syringe is resting against the septum cap; then push the plunger to the hilt and remove the syringe immediately from the chromatograph. This injection technique is necessary so that sharp symmetrical peaks will be obtained. 11.5 Calibration--Measure the area of both aromatic peaks and of the internal standard peak as directed in 12.4. Calculate the ratio of the benzene peak area to the MEK peak area. Plot the concentration of benzene versus the ratio. Make the same calculation and plot for toluene. See Fig. 4 for an example. This must be done to ensure that the entire chromatographic system is operating properly and that the concentration of any one component has not exceeded the linear response range of any part of the system: column, detector, integrator, and other components. The calibration should be linear. NOTE 12--If the calibration has been shown to be linear, a least squares calculation may be performed to calculatea calibration factor. The precisionstatementin Section 15 was developedfromdata obtained from calibrationplots and may not apply if calibration factorsare used. 12. Procedure

12.1 Preparationof Sample--Accurately measure 1.0 mL of MEK into a 25-mL volumetric flask. Fill to the mark with the sample to be tested and mix well. 12.2 Chromatographic Analysis--Chromatograph the sample, using the conditions established in 10.4 "time to backflush" and the injection technique described in 11.4. The valves must be turned to backflush mode at the time determined in 10.4 so that undesirable components do not enter Column B. 12.3 Interpretation of Chromatogram--Identify on the chromatogram the benzene, toluene, and the internal standard MEK peaks from the retention times of the standards.

11. Calibration and Standardization

11.1 StandardSamples--Prepare seven standard samples covering the range 0 to 5 volume % benzene and 0 to 20 volume % toluene as follows: For each standard, measure the volume of benzene and of toluene listed below into a 100-mL volumetric flask. Dilute to volume with isooctane, with all components and glassware at ambient temperature. Benzene

NOTE 13--The order of elution will be nonaromatichydrocarbons, benzene, MEK, and toluene using the prescribed OV I01 and TCEP. Figure 3 is an exampleof a typicalchromatogram. 12.4 Measurement of Area--Measure the areas under the aromatic peaks and under the MEK peak by conventional methods.

Toluene

Volume %

mL

5 2.5 1.25 0.6"/ 0.33 0.12 0.06

5.0 2.5 1.25 0.67 0.33 0.12 0.06

Volume % 20 y 15 , 10 ,/ 5 " 2.5 ,, I ," 0.5

mL 20.0 15.0 10.0 5.0 2.50 1.0 0.50

NOTE 14--The precision statement in Section 15 was developed from data obtained using electronic integrators or on-line computers. The precisionstatementmay not apply if other methodsof integration or peak area measurementare used. 556

I ~ D 3606

/

5.0 ~" m-

~

UNIDENTIFIED

/'--TOLUENE

4.0

"~--.-INTERNAL STANDARD (MEK) rq

BENZENE 3.0 o

"

]/NON

/

=-

A O.A, ICS

z

2,0

/

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I.O I

!

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RECORDER RESPONSE

-

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FIG. 3 Typical Chromatogram 13. Calculation 13.1 Calculate the ratios of the peak areas of benzene and toluene to the peak area o f MEK. Read from the appropriate calibration curve the liquid volume percent of benzene and toluene corresponding to the calculated peak ratios. 13.2 I f the results are desired on a mass basis, convert to mass percent as follows: Benzene, mass % - ( Vn/D ) × 0.8844 (1)

FIG. 4

0.2

BENZENE [ PEAK AREA VOL.% !BENZENE MEK 5.0 7508 6258 2.5 3874 6457 1,25 199i B401 0.67 IO52 6537 0.33 516 6532 0 12 183 6324 0.06 93 6166

i 0.4 1 10.6,

I,l,l,I

RATIO BENZENE/MEK 1.2OO 0.600 -O 311 0.161 0.079 0.029 0.015

O.S 1.0 1.2 1.4 RATIO z PEAK AREA BENZENE PEAK AREA MEK

, l 1.6

1.8

Typical Calibration Curve for Benzene (Determine for Each Analytical System)

operation of the test method, exceed the values in Table 2 only l case in 20: NOTE ISmln order to reflect changes in gasoline composition, the precision for this test method was determined in 1994 using both conventional gasolines as well as gasolines containing oxygenates (ethers such as methyl tort-butyl ether, ethyl tert-hutylether and tertamyimcthylether). The precision statement does not reflect results for gasolines that can contain alcohols. This precision should be used when the concentration of benzene (0.1 to 1.5 volume %) and toluene (1.7 to 9 volume %) fall within the specified range. The sample composition and results of the cooperative study are fried at ASTM headquarters as RR:D02-1042. Note 16--The precision was determined using conventional motor gasolines purchased on the open market. This precision should be used when the concentration of benzene exceeds 1.5 volume % and toluene 9 volume %. The sample compositions and results of the cooperative study are filed at ASTM Headquarters as RR:D-02-1042.

where: Vn ffi volume percent benzene, and D ffi relative density of sample at 15.6/15.6"C (60/60"F). Toluene, mass % --- (VT/D) x 0.8719 (2) where: Vr ffi volume percent toluene, and D ffi relative density of sample at 15.6/15.6"C (60/60"1=). 14. Report 14.1 Report the benzene and toluene contents in liquid volume percent to the nearest 0.1%. 15. Precision and Bias

TABLE 1 Repeatability NOTE~X = the mean volume • of the component.

15.1 The following criteria should be used for judging the acceptability of results (95 % confidence). The user should choose the precision statement that reflects the concentration range of each component under study. 15.1. I Repeatability---The difference between successive test results, obtained by the same operator with the same apparatus under constant operating conditions on identical test material would, in the long run, in the normal and correct operation of the test method, exceed the values in Table 1 only in 1 case in 20: 15.1.2 Reproducibility--The difference between two, single and independent results, obtained by different operators working in different laboratories on identical test material would, in the long run, in the normal and correct

Component

Range, volume ",~

Repeatability

See Note

Benzene Benzene Toluene Toluene

0.1-1.5 >1.5 1.7-9 >9

0.03(X) + 0.01 0.03 0.03(X) + 0.02 0.62

15 16 15 16

TABLE 2 Reproducibility NOTE--X ffi the mean volume Y, of the component.

557

Component

Range, volume ~

Repeatability

See Note

Benzene Benzene Toluene Toluene

0.1-1.5 >1.5 1.7-9 >9

0.13(X) + 0.05 0.28(X) 0.12(X) + 0.07 1.15

15 16 15 16

o 3so6 15.2 BiasmSince there is no accepted reference method suitable for measuring bias for this method, no statement of bias can be made.

16. Keywords 16.1 aviation gasoline; benzene; gas chromatography; gas. oline; toluene

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any Item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard Is subject to revision at any time by the responsible technical committee and must be reviewed every five years and ff not revised, either reepproved or withdrawn. Your comments are Invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend, ff you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 100 Barr Harbor Drive, West Conshohocken, PA 19428.

558

(~)

Designation: D 3700 - 94

An American National Standard

Standard Practice for Containing Hydrocarbon Fluid Samples Using a Floating Piston Cylinder I This standard is issued under the fixed designation D 3700; the number immediately following the designation indicates the year of original adoption or, in the case &revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsiion (0 indicates an editorial change since the last revision or re,approval.

laboratory test, can be useless if the samples are not valid.

1. Scope 1.1 This practice describes equipment and a procedure for obtaining a representative sample of a homogeneous hydrocarbon fluid and the subsequent preparation of that sample for laboratory analysis. 1.2 It is not possible, nor is it the intent of this practice, to provide a procedure that will be applicable for all sampling situations. It is strongly recommended that the samples be obtained under the supervision of a person knowledgeable in the phase behavior of hydrocarbon systems and experienced in all sampling operations. 1.3 This practice does not include recommendations for the location of the sampling point in a line or vessel, although the importance of the proper sampling location cannot be over-emphasized. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.For specific hazard statements, see 4. I and Annex A2.

4. Hazards 4.1 Safety Precautions: 4.1.1 WarningDSampling hydrocarbon fluids can be hazardous. Persons responsible for obtaining samples should be familiar with and adhere to safe practices for handling flammable fluid under pressure. 4.1.2 Disassembly of the piston cylinder for maintenance presents a special hazard. Should either end cap be removed while pressure is on the cylinder, the end caps and the piston can be ejected with such force as to cause serious injury to personnel and damage to adjacent equipment. The following steps are recommended for disassembly: 4.1.2.1 PrecautionnClamp the piston cylinder firmly to a steady work surface. 4.1.2.2 Vent both ends of the cylinder to atmospheric pressure before attempting to remove either end cap. 4.1.2.3 Clear the area at either end of the cylinder before loosening the end plug. 4.1.2.4 Provide a mechanical plunger to dislodge the piston from the cylinders. Do not use fluid pressure. 4.2 Technical Precautions: 4.2.1 A certain amount of information about a sample is necessary before it can be intelligently handled in the laboratory. Absolutely essential are the sample source, sample date, cylinder identification, sample pressure and temperature, ambient temperature, type of analysis required, and the sampling method used. There can be additional related facts such as field-determined results and operating conditions which will assist in the evaluation of the analytical data. This information should accompany the filled sample cylinder. 4.2.2 If the hydrocarbon fluid samples are to be transported by common carrier within the United States, the sample containers must meet the specifications and be labeled according to the Hazardous Materials Regulations of the Department of Transportation. 4.2.3 Containers must be thoroughly cleaned prior to sampling with an appropriate volatile solvent, for example, petroleum naphtha followed by acetone, and evacuated to remove traces of the solvent. The use of detergent/water solutions or steam is not recommended.

2. Summary of Practice 2.1 A hydrocarbon fluid sample is transferred under pressure from a source to a moving piston cylinder. The piston-type cylinder is designed to collect fluid samples by displacing a pressurizing fluid (usually an inert gas) at sampling pressure. The piston serves as a barrier between the sample and the inert gas which maintains the integrity of the sample by preventing the selective absorption of sample components in the pressurizing fluid as is possible in conventional displacement techniques. The method provides for a 20 % inert gas volume for safe storage and transport of the sample. 3. Significance and Use 3.1 The objective of any sampling operation is to secure, in a suitable container, an adequate portion of hydrocarbon fluid under pressure having the same composition as the stream being sampled. 3.2 Particular emphasis should be given to the necessity of obtaining accurate, representative samples for analysis since those analyses, regardless of the care and accuracy of the

5. Apparatus 5.1 Container, shown in Fig. 1 as Cylinder X, constructed of metal tubing, honed, and polished on the inside surface. The cylinder is closed with threaded end caps to provide access to remove and service the moving piston. The end caps are drilled and tapped for valves. The cylinder is

' This practice is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.H on Liquefied Petroleum Gases. Current edition approved July 15, 1994. Published September 1994. Originally published as D 3700 - 78. Last previous edition D 3700 - 78 (1988)~t

559

(I ~ D 3 7 0 0 designed to exceed the maximum pressure anticipated during sampling and to be resistant to materials being sampled, the pressurizing fluid, the cleaning solvents, and the expected corrodents. The volume of the cylinder will depend on the amount of sample needed for the laboratory analysis. 5.1.1 The cylinder contains a moving piston. The piston is equipped with O-rings, TFE-fluorocarbon rings, or other devices to affect a leak-free seal between the sample and the

Sample • source .

A

pressurizingfluid,and to allow for the freemovement of the piston within the cylinder.The use of guide rings is recommended to ensure smooth piston travel. The piston and scaling device must be resistantto the sample, the pressurizing fluid,the cleaning solvents,and expected corrodents. 5.1.2 All valves and safety devices must meet the appropriate material and pressure specifications. 5.2 Displacement Container--This container, Fig. I, Cylinder Y, shallbe fabricatedfrom metal tubing, be designed to meet the same pressure requirements as the piston cylinder, and have a volume of no more than 80 % of the pressurizing volume of the piston cylinder (80 % of piston cylinder volume minus the volume of the piston). 5.3 Transfer Lines, Valves, and Gages--The transfer system shall be designed to exceed the maximum anticipated pressure and be resistant to all expected corrodents. The transfer lines should have a minimum diameter of 6.35 mm (V4 in.) and be as short as is practical, see Fig. 1. The use of filters and dryers is discouraged.

MI

6. J_aboratory Preparation 6.1 The following procedure is recommended for liquidphase samples: 6.I.l Check the sample pressure on inert gas end, Valve D. The sample pressure should equal the sample source pressure corrected for the laboratoryambient temperature. 6.1.2 Connect the external pressure source of inert gas to Valve D and adjust the sample pressure equal to the saturation pressure of the sample at the laboratoryambient temperature plus a minimum of 1380 kPa (200 psi). 6.1.3 Rock the sample cylinderto ensure that the sample is homogeneous. 6.1.4 Place the cylinder in a horizontal position. The sample is now ready to transfer for analysis. The pressure described in 6.1.2 must be maintained on the sample during the transferoperation. 6.1.5 For use with gaseous phase samples, referto Annex Al.

Sample Floating piston Inert gas

Cylinder ,,X,J

7. Sampling Procedure

7.1 Use the displacement cylinder technique for the liquid phase samples. 7.1.1 With the sample side of the piston cylinder evacuated (from cleaning operation) and Valve C closed, fill the displacement end with an inert gas to approximately (68.9 kPa) (10 psi) above the sampling pressure. Close Valve D. 7.1.2 Connect piston Cylinder X to sample Source A and displacement Cylinder Y to piston cylinder as shown in Fig. 1. Fill the displacement cylinder with air at atmosphere pressure. 7.1.3 With Valves B and C closed, open sample source Valve A to full open position. Observe the sample source pressure on Gage M. Crack Valve B and fitting to Valve C to purge line. Do not allow Pressure M to drop below sample pressure. Tighten fitting to Valve C and close Valve B. 7.1.4 With Valve E closed, open Valve D and observe pressure on Gage N. Adjust pressure N to equal pressure M by slowly venting inert gas through Valve E. Close Valve E. 7.1.5 With Valve E closed, slowly open Valve C to full open. There should be no pressure drop indicated on Gage N. 7.1.6 Close Valve D. Open Valve E and vent pressure at

Cylinder ,,y,,

Figure I

Sampling system for hydrocarbon fluids (Not)o scale)

FIG. 1 Sampling System for Hydrocarbon Fluids 560

q~) D 3700 Disconnect displacement cylinder. Disconnect piston cylinder from sample source. 7.1.9 Do not take outage or reduce pressure on piston cylinder. Check Valves C and D for leaks, plug valves to protect threads, prepare sample information tag, and box for transport.

atmosphere through Valve F. Close Valve F. 7.1.7 Slowly open Valve D allowing inert gas to flow into Cylinder Y. Observe Gage M so as not to allow pressure M to drop. Continue operation until pressure N equals pressure M. At this point, a volume equal to Cylinder Y has been displaced from Cylinder X by the hydrocarbon fluid sample. Sample Cylinder X now contains 80 volume % of sample leaving sufficient inert gas space to ensure safe storage and transport. 7.1.8 Close Valves D, C, and A. Open Valves B and F.

8. Keywords 8.1 floating piston cylinder; hydrocarbon fluid sampling; LP-gas; sampling

ANNEXES

(Mandatory Information) A1. GAS-PHASE SAMPLING AI.I The piston cylinder method is believed to be applicable for both liquid-phase and gaseous-phase samples. However, while the technique has been successfully used for liquid samples, there is no experience obtaining gas-phase samples. AI.2 The technique for obtaining gas-phase samples would be identical to the procedure described in Section 7. A1.3 The technique for the laboratory preparation of a gas phase sample is somewhat different from that described in Section 6. The following procedure is recommended for the laboratory preparation of gas-phase samples: AI.3.1 Check sample pressure on inert gas end, Valve D. The sample pressure should equal the sample source pressure corrected for laboratory ambient temperature. A1.3.2 Heat the sample cylinder for a minimum of I h at the hydrocarbon dew point (if known) or the sample source temperature, plus I l+*C (20*F). AI.3.3 If the gas sample is known to be "dry" (does not form condensation on cooling by expansion), the sample is now ready to transfer for analysis. If the sample is known to be "wet" (partially condenses upon cooling or by a variation in pressure), the sample pressure must be maintained on piston cylinder during transfer by adding inert gas, Valve D, from external pressure source. All gases of unknown composition or exceeding 345 kPa (500 psi) sample source pressure should be treated as "wet" gases. A.1.3.4 The transfer line from the sample cylinder to analytical instrument should be heat-traced. A I.4 Some piston-type cylinders are fabricated from nonmagnetic materials such as the 300 series of stainless

steels and the piston from magnetic carbon steel. With this type of cylinder construction, the progress of the piston movement during sample entry can be followed by placing a small magnet on the outside surface of the cylinder. This technique eliminates the need for the displacement container and simplifies the sampling procedure. The following procedure is recommended: A 1.4.1 With the sample side of piston cylinder evacuated from the cleaning operation and Valve C closed, fill the displacement end, Valve D, with inert gas to sampling pressure. Close Valve D. A 1.4.2 With Valves B and C closed, open sample source Valve A to full open position. Observe sample source pressure on Gage M. Crack fitting to Valve C and purge line. Do not allow Pressure M to drop below sample pressure. Tighten the fitting. AI.4.3 Check pressure of inert gas side, Valve D, and adjust to equal Pressure M. AI.4.4 Slowly open Valve C to full open. There should be no pressure drop at Gage N. AI.4.5 Crack Valve D allowing inert gas to purge to atmosphere. Do not allow Pressure M to drop below sampling pressure. Continue purge until the piston has moved 80 % of the length of the cylinder as indicated by the magnet locator. Close Valves D, C, and A. Open B and disconnect piston cylinder from sample source. AI.4.6 Do not take outage or reduce pressure on piston cylinder. Check Valves C and D for leaks, plug valves to protect threads, prepare sample information tag, and box for transport.

561

~

D 3700

A2. PRECAUTIONARY STATEMENTS A2.1.5 Avoid buildup of vapors and eliminate all sources of ignition, especially nonexplosive electrical devices and heaters. A2.1.6 Avoid prolonged breathing of vapor or spray mist. A2.1.7 Avoid prolonged or repeated skin contact.

A2.1 Flammable Liquefied Gases

A2.1.1 A2.1.2 A2.1.3 A2.1.4

Vapors may cause flash fires. Keep away from heat, sparks, and open flame. Keep container closed. Use with adequate ventilation.

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reapproved or withdrawn. Your comments are Invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical cornm/ttea, which you may attend, ff you feel that your comments have not received • fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, Pit 19103.

562

@ @

Designation: D 3701 - 92

An American National Standard

Designation:337/85(90) Standard Test Method for Hydrogen Content of Aviation Turbine Fuels by Low Resolution Nuclear Magnetic Resonance Spectrometry 1 This standard is issued under the fixed designation D 3701; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (~) indicates an editorial change since the last revision or reapproval.

1. Scope 1.1 This test method covers the determination of the hydrogen content of aviation turbine fuels. 1.2 Use Test Method D 4808 for the determination of hydrogen in other petroleum liquids. 1.3 The preferred units are mass percent hydrogen. 1.4 This standard does not purport to address all of the

safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For a specific precautionary statement, see Note I.

2. Referenced Documents

2.1 A S T M Standards: D4057 Practice for Manual Sampling of Petroleum and Petroleum Products2 D4808 Test Method for Hydrogen Content of Light Distillates, Middle Distillates, Gas Oils, and Residua by Low-Resolution Nuclear Magnetic Resonance Spectroscopy2

3. Summary of Test Method 3.1 A sample of the material is compared in a continuous wave, low-resolution, nuclear magnetic resonance spectrometer with a reference standard sample of a pure hydrocarbon. The results from the integrator on the instrument are used as a means of comparing the theoretically hydrogen content of the standard with that of the sample, the result being expressed as the hydrogen content (percent weight basis) in the sample. 4. Significance and Use 4. I The combustion quality of aviation turbine fuel has traditionally been controlled in specifications by such tests as smoke point, smoke volatility index, aromatic content of luminometer number. Evidence is accumulating that a better control of the quality may be obtained by limiting the minimum hydrogen content of the fuel.

4.2 Existing methods allow the hydrogen content to be calculated from other parameters or determined by combustion techniques. The method specified provides a quick, simple, and more precise alternative to these methods.

5. Apparatus 5. I Nuclear Magnetic Resonance Spectrometer3mA lowresolution continuous-wave instrument capable of measuring a nuclear magnetic resonance of hydrogen atoms, and fitted with: 5.1.1 Excitation and Detection Coil, of suitable dimensions to contain the test cell. 5.1.2 Electronic Unit, to control and monitor the magnet and coil and containing: 5.1.2.1 Circuits, to control and adjust the radio frequency level and audio frequency gain. 5.1.2.2 Integrating Counter, with variable time period in seconds. 5.2 Conditioning Block--A block of aluminum alloy drilled with holes of sufficient size to accommodate the test cells with the mean height of the sample being at least 20 mm below the top of the conditioning block (see Fig. 1). 5.3 Test Cells--Nessler-type tubes of approximately 100mL capacity with an external diameter of 33.7 _+ 0.5 mm and an internal diameter of 31.0 _+ 0.5 mm marked at a distance of 51 mm above the bottom of the tube by a ring around the circumference. 5.4 Polytetrafluoroethylene (PTFE) Plugs for Closing Test Cells--Plugs as shown in Fig. 1 made from pure PTFE and a tight fit in the test cells. 5.5 Insertion Rod--A metal rod with a threaded end as shown in Fig. 1 for inserting and removing PTFE plugs from test cells. 5.6 Analytical Balance--Top pan type, capable of weighing the test cells in an upright position to an accuracy of _0.01 g. 3 This method has been written around the Newport Analyzer Mark IIIF (Oxford Analytical Instruments, Ltd., Oxford, England) and the details of the method should be read in conjunction with the manufacturer's handbook. This particular instrument was the only instrument available when the precision program was carried out. Any similar instrument would be accepted into the above method provided the new instrument was adequately correlated and proved to be statistically similar. The Newport Analyzer Mark IIIF is no longer in production and is being replaced by the manufacturer with the Newport 4000. The Newport 4000 model instrument has been demonstrated to provide equivalent results to those obtained with the Mark Ill models which were used to generate the precision data.

This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.03 on Elemental Analysis. Current edition approved March 15, 1992. Published May 1992. Originally published as D 3701 - 78. Last previous edition D 3701 - 87. 2 Annual Book of ASTM Standards, Vol 05.03.

563

~}

D 3701 - (~ 337 2 HOLES 105 DEEP

8 HOLES 105 DEEP

PLASTIC

/ /KNOB

I

LID

I~

METAL INSERTION ROD APPROX 6 ~

39 ¢ 35 ¢ 45~

\

i/

I

i

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I '

II

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I

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THREAD

/

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i

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CONDITIONING BLOCK MATERIAL ALUMINIUM ALLOY

oa-

PLUG MATERIAL PTFE

NOTE--Dimensionsare in millimetms. FIG. 1 Hydrogen Content of Aviation Turbine Fuels

564

L

~

D 3701 - (~) 337 below the 51-mm mark on the test cell. Unscrew the insertion rod carefully without disturbing the plug. 9.4 Place the reference standard in the sample conditioning block. 9.5 Repeat the procedure outlined in 9.1 to 9.4 using the material to be tested.

6. Materials 6.1 Reference agent grade.

Standard--n-Dodecane

of analytical re-

NOTE 1: Warning--Flammable.

7. Sampling 7.1 Take a homogenous sample in accordance with Practice D 4057.

10. Procedure 10.1 Leave the sample and reference standard in the conditioning block for at least 0.5 h to ensure they reach uniform temperature, that is room temperature, before measurements are made. 10.2 Take the reference standard and place it carefully in the coil. When fully entered the top of the test cell should be just above the cover of the spectrometer unit. 10.3 Check that the peaks on the oscilloscope are coincident and if this is not so, adjust the tuning until they are. 10.4 When the reference standard has been in the magnet unit for at least 3 s, push the reset button.

8. Preparation of Apparatus 8.1 Read the following instructions in conjunction with the manufacturer's handbook. Preparation of the instrument is not critical but take care to prevent rapid temperature fluctuations of the instrument and the conditioning block, for example, avoid them in direct sunlight or draught. 8.2 The results obtained during the use of the equipment are susceptible to error arising from changes in the magnetic environment. Exercise care to ensure that there is a mini m u m of magnetic material in the immediate vicinity of the equipment and that this be kept constant throughout the course of a series of determinations. 8.3 Set the instrument controls to the following conditions: NOTE 2--On new NMR instruments with variable gates the gate should be set at 1.5 gauss to comply with nonvariable gate instruments. Radio frequencylevel 20 laA Audio frequencygain 500 on dial Integrationtime 128 s

NOTE 4mIt is important that a delay of this magnitude be allowed before commencing measurement in order that the hydrogen nuclei are fully polarized in the magnetic field. 10.5 After a count time of 128 s the digital display will stop at its final value. Record the integrator counts and push the reset button again and record the second reading. 10.6 Weigh the cell and contents and record the total weight. 10.7 Replace the reference standard in the conditioning block and make similar duplicate readings on the sample to be tested.

8.4 Switch on the main supply to the spectrometer and allow it to warm up for at least 1 h. 8.5 Place a test cell containing sample in the coil and adjust the tuning of the instrument until the two resonance curves on the oscilloscope are coincident. This setting may need to be readjusted during determinations. 8.6 Remove the test cell from the coil and observe that the signal readout is now zero + 3 digits. This should be checked periodically during the series of tests to ensure that no contamination of the coil has occurred.

NOTE 5mMeasurements will be altered by temperature variations in

the sample and reference standard so these must be returned to the conditioning block when measurements are not being made. NOTE 6--The determined hydrogen content will be affected by any instrument drift, slight variations in temperature between the sample and reference standard and loss of sample or reference standard, or both, due to evaporation. Therefore when a series of results are to be determined, sample and reference standard should be measured, weighed and calculated as pairs. When the weight change of the reference standard is greater than 0.01 g between consecutive weighings, the cause of this should be investigated and corrected. Losses are usually due to poor fitting of the PTFE plug while gains will probably be due to contamination of the coil.

9. Preparation of Samples and Standard 9.1 Take a clean, dry test cell and PTFE plug and weigh them together to the nearest 0.01 g and record the weight. Add 30 + 1 m L of the reference standard to the tube, taking extreme care to prevent splashing the liquid above the line inscribed on the tube. The use of a pipet is recommended for this operation. 9.2 Using the insertion rod, push the PTFE plug into the tube until it is just above the liquid-surface, keeping the tube upright. A gentle twisting of the plug as it is inserted will aid the escape of air from the test cell and normally ensure that the lip of the plug is turned up around the entire circumference. Take care to ensure that this is so, as a plug that is not properly inserted will allow rapid sample evaporation and give rise to change in the results obtained.

11, Calculation 11.1 For each sample and reference standard, subtract the weight of the test cell and PTFE plug from total weight of the test cell determined in 10.6 Hydrogen content, mass % = -~R x W_~ x 15.39

Wr

NOTE 3--The insertion of the PTFE plug can be facilitated by inserting a length of thin (less than 0.2 mm diameter) copper wire down the inside surface of the disc until it is approximately 38 mm from the graduation mark and then pushing the PTFE plug down past the wire which is then removed. 9.3 The bottom rim of the plug should be at or slightly 565

where: ST = SR = WR = Wr =

mean of integrator counts on sample under test, mean of integrator counts on reference standard, mass of reference sample, and mass of sample under test

12. Report 12.1 Report the mass percent hydrogen content to the nearest 0.01 mass %.

~)

D

3701 -

337 0.09 mass %

13. P r e c i s i o n and Bias 4

13.1.2 R e p r o d u c i b i f i t y - - T h e difference between two single and independent results obtained by different operatots working in different laboratories on identical test material would, in the long run, in the normal and correct operation of the test method exceed the following value only in one case in twenty:

13.1 The precision of the method as obtained by statistical examination of interlaboratory test results is as follows: 13. I . 1 R e p e a t a b i l i t y - - T h e difference between successive test results obtained by the same operator with the same apparatus under constant operating conditions on identical test material would, in the long run, in the normal and correct operation of the test method exceed the following value only in one case in twenty:

4

(~)

0.11 mass %

Supportingdataare availableand on loan fromASTMHeadquarters.Request

RR: D02-1 t86.

13.2 B i a s - - A 1977 research report indicated that the hydrogen content determined by this test method is biased high with respect to the expected value for pure known materials.

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of,infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and ff not revised, either reepproved or withdrawn. Your comments are invited either for revision.of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend, ff you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103.

566

Designation:

D 3710

- 95

An AmericanNationalStandard

Standard Test Method for Boiling Range Distribution of Gasoline and Gasoline Fractions by Gas Chromatography 1 This standard is issued under the fixed designation D 3710; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number m parentheses indicates the year of last reapproval. A superscript epsilon (~) indicates an editorial change since the last revision or reapproval.

mixture relative to an arbitrarily chosen component. 3.1.4 response factorma constant of proportionality that converts area to liquid volume. 3.1.5 system noise--the difference between the maximum and minimum area readings per second for the first 20 area readings in the blank run. 3.1.6 volume count--the product of the area under a peak and a response factor.

1. Scope 1.1 This test method covers the determination of the boiling range distribution of gasoline and gasoline components. This test method is applicable to petroleum products and fractions with a final boiling point of 500*F (260°C) or lower as measured by this test method. 1.2 This test method is designed to measure the entire boiling range of gasoline and gasoline components with either high or low Reid vapor pressure and is commonly referred to as gas chromatography (GC) distillation (GCD). 1.3 This test method has not been validated for gasolines containing oxygenated compounds (for example, alcohols or ethers). 1.4 The values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are for information only. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements, see Notes 9, 10, 11, and 15.

4. Summary of Test Method 4.1 The sample is introduced into a gas chromatographic column which separates hydrocarbons in boiling point order. Conditions are selected so as to measure isopentane and lighter saturates discretely. Normal pentane and heavier compounds are not completely resolved but are measured as pseudo components of narrow boiling range. The column temperature is raised at a reproducible rate and the area under the chromatogram is recorded throughout the run. Boiling temperatures are assigned to the time axis from a calibration curve, obtained under the same conditions by running a known mixture of hydrocarbons covering the boiling range expected in the sample. From these data the boiling range distribution of the sample is obtained.

2. Referenced Documents

5. Significance and Use 5.1 The determination of the boiling range distribution of gasoline by GC distillation provides an insight into the composition of the components from which the gasoline has been blended. This insight also provides essential data necessary to calculate the vapor pressure of gasoline, which has been traditionally determined by Test Method D 323. In addition, the Test Method D 86 distillation curve can be predicted using GCD data. See Annex A 1. 5.2 The GCD method facilitates on-line controls at the refinery, and its results offer improved means of describing several car performance parameters. These parameters inelude: (1) car-starting index, (2) vapor-lock index or vaporliquid ratio, and (3) warm-up index. The car-starting and vapor-lock indexes have been found to be mostly affected by the front end of the Test Method D 86 distillation curve (up to about 200*F (93"C)). The warm-up index is affected by the middle and to a lesser extent by the back end of the Test Method D 86 curve, that is, the temperatures corresponding to the 50 to 90 % off range. Since the boiling range distribution provides fundamental information on composition, an improved expression for the above performance parameters may be worked out, even when the boiling range distribution curve is not smooth. Currently, car performance cannot be assessed accurately under such conditions.

2.1 ASTM Standards." D 86 Test Method for Distillation of Petroleum Products2 D323 Test Method for Vapor Pressure of Petroleum Products (Reid Method)2 D 1265 Practice for Sampling Liquefied Petroleum (LP) Gases (Manual Method)z D4057 Practice for Manual Sampling of Petroleum and Petroleum Products3 3. Terminology 3.1 Definitions." 3.1.1 final boiling point (FBP)--the point at which a cumulative volume count equal to 99.5 % of the total volume count under the chromatogram is obtained. 3.1.2 initial boiling point (IBP)--the point at which a cumulative volume count equal to 0.5 % of the total volume count under the chromatogram is obtained. 3.1.3 relative molar response--the measured area of a compound divided by the moles present in the synthetic This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.04.0H on Chromatographic Methods. Current edition approved Sept. 10, 1995. Published November 1995. Originally published as D 3710 - 78. Last previous edition D 3710 - 93. 2 Annual Book o./ASTM Standards, Vol 05.01. 3 Annual Book oJ ASTM Standards, Vol 05.02.

6. Apparatus 6.1 ChromatographmAny gas chromatograph may be 567

iI~) D 3710 TABLE

1

Repeatability

as a Function

of Percent

Repeatability, Volume Percent Recovered, dT/dV:

Recovered

dT/dV

and

r, °F (*C)

0

2(1)

4(2)

6(3)

6(4)

10(6)

12(7)

14(8)

20(11 )

30(17)

IBP

2(1)

2(1)

2(1)

2(1)

2(1)

2(1)

2(1)

2(1)

2(1)

1

2(1)

2(1)

2(1)

2(1)

2(1)

2(1)

2(1)

2(1)

--

5 10

2(1)

2(1)

2(1)

2(1)

2(1)

2(1)

2(1)

2(1)

--

2(1) ---

2(1) 2(1 ) 2(1 )

2(1) 3(2) 3(2)

2(1) 4(2) 4(2)

2(1) 5(3) 5(3)

2(1) 7(4) 7(4)

2(1) 10(6) 10(6)

2(1) . 14(8)

--

--

--

95 99

__A .

__

3(2)

9(6)

.

5(3) .

7(4)

.

2(1 ) .

-6(3)

--6(3)

FBP

.

.

.

6(3)

6(3)

20 30

to 9 0

.

.

.

.

.

.

.

2(1) . 19(10) 13(7) 6(3)

.

40(22) 2(1)

.

6(3)

6(3)

CONCENTRATION DATA Repeatability, r, Component

C3

iC4

nC4

iC5

-0.02 0.02 ----D

0.02 0.02 0.03 0.03 0.04 0.05 0.05 0.06 0.07

--------D

~

0.07

--------_ --

Volume 0.10 0.15 0.20 0.4 0.6 0.8 1.0 1.2 1.4 1.6 2 4 6 8 10 12 14 16 18 20 22

--~ -~ ---~ ~ --

A (_) Outside the range observed in the cooperative

-0.11 0.22 0.32 0.43 0.54 0.65 0.76

0.86 ----

0.25 0.28 0.30 0.32 0.34 0.36 0.39 0.41 0.43 0.45

study

used that meets the performance requirements in Section 8. Place in service in accordance with manufacturer's instructions. Typical operating conditions are shown in Table 3. 6.1.1 Detector--Either a thermal conductivity or a flame ionization detector may be used. Detector stability must be such that the sensitivity and baseline drift requirements as defined in Section 8 are met. The detector also must be capable of operating continuously at a temperature equivalent to the m a x i m u m column temperature employed, and it must be connected to the column so as to avoid any cold spots.

15 s for propane and of allowing elution of the entire sample within a reasonable time period. Subambient capability may be required. The programming rate must be sufficiently reproducible to meet the requirements of 8.7. NOTE 3--If the column is operated at subambient temperature, excessively low initial column temperature must be avoided, to ensure that the stationary phase remains liquid. The initial temperature of the column should be only low enough to obtain a calibration curve meeting the specifications of this test method.

NOTE l--Care must be taken that the sample size chosen does not allow some peaks to exceed the linear range of the detector. This is especially critical with the flame ionization detector. With thermal conductivity detectors, sample sizes of the order of 1 to 5 laL generally are satisfactory. With flame ionization detectors, the sample size should not exceed I IsL. NOTE 2--It is not desirable to operate the detector at temperatures much higher than the maximum column temperature employed. Operation at higher temperatures only serves to shorten the useful life of the detector, and generally contributes to higher noise levels and greater drift.

6.1.2 Column TemperatureProgrammer--The chromatograph must be capable of program temperature operation over a range sufficient to establish a retention time of at least

568

6.1.3 Sample Inlet System--The sample inlet system must be capable of operating continuously at a temperature equivalent to the maximum column temperature employed, or provide on-column injection with some means of programming the entire column, including point of sample introduction up to the maximum temperature required. The sample inlet system must be connected to the chromatographic column so as to avoid any cold spots.

6.1.4 Flow Controllers--Chromatographs must be equipped with constant-flow controllers capable of holding carder gas flow constant to + 1 % over the full operating temperature range. 6.2 Sample Introduction--Sample introduction may be either by means of a constant-volume liquid sample valve or by injection with a microsyringe through a septum. If the sample is injected manually, cool the syringe to 0 to 4"C (32 to 40°F) before taking the sample from the sample vial.

tl~) D 3710 TABLE

2

Reproducibility

as n Function

of Percent

Recovered

dT/dv

end

Reproducibility, R, *F (*C) A Volume Percent Recovered, dt/dv: IBP 1 5 10 20 3 0 to 90 95 99 FBP

0 7(4) 5(3) 5(3) 6(3) 5(3) 6(3) _ e . .

2(1 ) 7(4) 5(3) 5(3) 6(3) 7(4) 9(5) __ .

4(2) 8(4) 5(3) 5(3) 6(3) 11 (6) 13(7) 11 (6) .

. .

.

.

6(3) 8(4) 6(3) 5(3) 6(3) 16(9) 20(11) 16(9) . .

8(4) 8(4) 6(3) 6(3) 6(3) 23(13) 27(15) 23(13) . . .

10(6) 8(4) 6(3) 5(3) 5(3) 30(17) 36(20) 30(17) .

12(7) 8(4) 6(3) 6(3) 3(7) . 46(26) 36(21 )

.

14(8) 8(4) 6(3) 6(3) . . 55(31) 46(26) 20(11 )

.

.

20(11 ) 30(17) 9(5) 1 0(6) ----. . . . ----24(13) 33(18) 19(11 ) 26(14)

40(22) 12(7) ---

--36(20) 36(20)

A For thermal conductivity detectors. For flame ionization detectors (FID), reproducibilities, R, a r e the s a m e e x c e p t in the 2 0 to 95 % recovered range where: RRO = 0 . 9 0 RTCO Reproducibility, R C3 Detector

iC4

Detector Bias (FID-TCD)

nC4

Both

TCD

FID

-0.13 0.13 --~ ----------~ -. . .

0.10 0.10 0.10 0.12 0.13 0.15 0.16 0.18 0.19 0.20 ~ ---~ -~ --

0.09 0.11 0.13 0.20 0.27 0.34 0.41 0.48 0.55 0.62 ~ ~ --~ ~ -~ . . .

TCD

iC5 FID

TCD

C3

iC4

nC4

-0.00 0.00 ~ ~ -~ -~ -~ ~ ~ ----~ ~ ~ ~

0.00 0.00 0.00 -0.01 -0.03 -0.04 -0.05 -0.06 -0.07 -0.09 ----~ ---~ u ~

-~ ----~ ~ ---0.33 -0.28 -0.24 -0.19 -0.14 -0.10 -0,05 -0.01 -~ --

iC5

FID

Volume 0.10 0.15 0.20 0.4 0.6 0.8 1.0 1.2 1.4 1.6 2 4 6 8 10 12 14 16 18 20 22

. . .

. . .

0.28 0.57 0.85 1.14 1.42 1.70 1.99 2.27

1.62 1.91 2.19 2.48 2.76 3.04 3.33 3.61

. . .

0.79 0.98 1.15 1.35 1.54 1.72 1.91 2.09 2.28 2.48

0.29 0.48 0.66 0.85 1.04 1.22 1.41 1.59 1.78 1,97

------0.27 -0.14 0.00 +0,14 +0.28 +0.42 +0.55 +0.69 +0.83 +0.97

e (_) O u t s i d e the range observed in the cooperative study.

NOTE 4--Automatic liquid-sampling devices or other sampling means, such as sealed septum-capped vials, may be used, provided no loss of light ends occurs. The system must be operated at a temperature sufficiently high to vaporize completely hydrocarbons with an atmospheric boiling point of 500*F (260"C), and the sampling system must be connected to the chromatographic column so as to avoid any cold spots.

temperature to reduce baseline shifts due to bleeding of column substrate. NOTE 5--The column can be conditioned very rapidly and effectivelyby the following procedure: (1) Disconnect column from detector. (2) Purge the column thoroughly at ambient temperature with carrier gas. (3) Turn off the carrier gas and allow the column to depressurize completely. (4) Raise the column temperature to the maximum operating temperature and hold at this temperature for at least 1 h with no flow through the column. (5) Cool the column to at least 100°C before turning on carrier gas again. (6) Program the column temperature up to the maximum several times with normal carrier gas flow. The column then should be ready for use. NOTE 6wAn alternative method of column conditioning, which has been found effective for columns with an initial loading of l0 % liquid phase, consists of purging the column with carrier gas at the normal flow rate while holding the column at maximum operating temperature for 12 to 16 h.

6.3 Recorder--A recording potentiometer or equivalent with a full-scale response time of 2 s or less may be used. 6.4 Column--Any column and conditions may be used, provided, under the conditions of the test method, separations are in order of boiling points and the column meets the performance requirements in Section 8. See Table 3 for columns and conditions that have been used successfully. Since a stable baseline is an essential requirement of this test method, provisions must be made to compensate for column bleed. Traditionally this is done by using matching dual columns and detectors. At best, this procedure is only marginally successful. An even more satisfactory procedure is to record the area profile of the column bleed during a blank run, and subtract this profile from subsequent sample runs, as outlined in 11.1. 6.4.1 Column Preparation--Any satisfactory method, used in the practice of the art, that will produce a column meeting the requirements of Section 8, may be used. The column must be conditioned at the maximum operating

6.5 Integrator--Means must be provided for determining the accumulated area under the chromatogram. This can be done by means of a computer, or automatic operation can be achieved with electronic integration. A timing device is used to record the accumulated area at set time intervals. The same basis for measuring time must be used to determine 569

~) D 3710 TABLE 3

Gas Chromatography Column and Conditions

Column: Liquid phase, material weight % Solid support, material mesh size Length, m (ft) Outside diameter, mm (in.)

UCW-982 10 Chromosorb P 80/100 0.5 (1 .S) 6.4 (1/4)

Supelco 2100 20 Chromosorb W 80/100 1.5 (5) 3.2 (1/5)

UCW-98 10 Chromosorb G 60/80 0.9 (3) 6.4 (1/4)

OV-101 10 Chromosorb P 60/80 1.2 (4) 3.2 (1/8)

UCW-98 10 Supelcoport 80/100 1.5 (5) 3.2 (1/8)

-30 250 250 250

40 250 250 300

-20 200 345 345

0 250 250 250

0 230 250 230

10.6 He 50 3 150 mA

16 He 30 2 160 mA

10 He 60 3 135 mA

15 He 29 2 ...

16 He 30 1 175 mA

TC automatic syringe integrating A/D 2

TC syringe integrating A/D 1/2

TC syringe integrating A/D 5

Temperatures: Initial column temperature, =C Final column temperature, =C Detector temperature, *C Injection zone temperature, *C Operating Variables: Program rate, *C/rain Carrier gas flow rate, cma/min Sample size, ~tL Detector voltage (or mA)

Instrument: Detector type Sampling system Area measurement method Time slices per second

retention times in the calibration, the blank, and the sample. If an electronic integrator is used, the maximum area measurement must be within the linear range of the inte= grator. 6.6 Sample ContainersmPressure cylinders or vials with septums should be provided for the calibration mixture and samples to avoid loss of light ends. 6.7 System~Any satisfactory combination of the above components that will meet the performance requirements of Section 8. 7.

TC

TC

valve

valve

time slice 5

time slice 1/2

for use with flame ionization detectors. (Warning--See Notes 10 and 11.) NOTE 10: W a r n i n g - - H e l i u m , nitrogen, a n d argon are compressed

gases under high pressure. NOTE 1 1: Warning--Hydrogen is an extremely flammablegas under high pressure. 7.3 Liquid Phase for Columns: NOTE 12--The following materials have been used suceessfuUy as liquid phases: Silicone gum rubber GE-SE-304 Silicone gum rubber OV-I s Silicone gum rubber OV-1015 Silicone gum rubber Snp¢lco 21006 Silicone gum rubber UC-W987

Reagents and Materials

7.1 Calibration MixturemA synthetic mixture of pure liquid hydrocarbons of known boiling point covering the boiling range of the sample. At least one compound in the mixture must have a boiling point equal to or lower than the initial boiling point of the sample, and one compound must have a retention time greater than any component in the sample. The concentration of all compounds heavier than n-butane must be known within 0.1%. The synthetic composition shown in Table 2 should be used for gasoline analysis. Compounds necessary for evaluation of system performance are noted in Table 4.

7.4 Solid Support--Usually crushed fire brick or inert diatomaceous earth such as Chromosorb P, G, or W, 8 acid-washed, dimethyl silanized. Sieve size and support loading should be such that it will give optimum resolution and analysis time. In general, support loadings of 3 to 10 % have been found most satisfactory but higher ones have been used as shown in Table 3. 8.

S y s t e m Performance

NOTE 7--If the sample contains significant quantities of compounds

8.1 Resolution--For samples containing isopentane and

that can be identified on the chromatogram, these peaks may be used as

lighter materials, the system must be able to identify the beginning and end of isopentane and lighter saturated compounds as they elute from the column. Individual peaks must be resolved from adjacent peaks so that the height at the valley above the baseline is not more than 5 % of,the height of the smaller peak adjacent to it. The resolution, R, between nCi2 and nCt3 must be between 2 and 4 when calculated in accordance with the following equation as shown in Fig. l:

internal boiling point calibrations. NOTE 8--Two calibration mixtures can be used for convenience. One that contains known concentrations of isopentane and heavier compounds can be used for determining response factors, sensitivity, and concentration repeatability. The other would contain a complete boiling range of compounds including propane, butane, and isobutane, whose concentrations are known only approximately. It would be used for measuring resolution, skewness, retention time repeatability, polarity, and retention time-boiling point relationship. NffrE 9--If the sample is known to contain more than 5 % benzene, 2,4 dimethylpentane should be replaced with benzene in the calibration mixture. (WarningMBenzeneis poisonous and carcinogenic,harmful or fatal if swallowed.)

7.2 Carrier GasmHelium or hydrogen for use with thermal conductivity detectors. Nitrogen, argon, or helium 570

4 Registered trademark s Registered trademark 6 Registered trademark 7 Registered trademark s Registered trademark

of General Electric Co. of Ohio Valley Specialty Chemical Co. of Supelco, Inc. of Union Carbide Co. of Johns-Manville Co.

~

D 3710

g n C12

n C1}

E rG u')

r~3 Z 0 J

¢&3

Y]. sec. Y2' sec. FIG. 1

Column Resolution

R = 2D/(Y, + }'2)

(1)

0.05

where: D = time, s, between nC~2 and nC~3 apexes, Y, = peak width of nCz2, s, and Y2 = peak width of nC~3, s. 8.2 Sensitivity and NoisemThese criteria test the sensitivity and noise of the total system. From the first 20 readings or time intervals of the blank run, calculate the noise as the difference between the maximum area reading per second minus the minimum reading per second. From the measurements on the calibration mixture, calculate the signal/noise ratio, as follows:

A/(N x S)

TIME FIG. 2

where: A = total area of the hexane peak, N = noise, and S = width of the hexane peak in seconds. This value must not be less than 10 for each 0.05 volume % of hexane in the calibration mixture, for example, 200 for 1%. If the noise is undetectable, assume the noise to be 1 count per second. 8.3 Drift--From the blank run, calculate by the following test procedure, a total area measured after the start of the run

Peak Number

Compound Identification

1e

nCa

2e

isoC4

3e 4a 5 6 7c 8D 9 10 o 11 12c 13 c 14 15 c 16 c 17 c 16 19

nC4 isoC s

nCs 2-MeC 5 nCe 2,4-DiMeCs nC7 Toluene nCe p-Xyiene n-Propylbenzene nClo n-Butylbenzene nC12 nCla nC14 nC15

Peak Skewness

until the end of the run. Adjust the apparatus so that all measurements can be read whether positive or negative. On some equipment such as integrators, readings will need to be positive and increasing in value. Obtain the absolute difference between the average area reading in the first five time intervals and the individual readings in each time interval from the start of the blank run until the end. Sum these differences to obtain the total area for the blank. The total area measurement from the blank run must not be greater than 2.0 % of the total area measurement of the calibration mixture. 8.4 Skewing of Peaks--Calculate the ratio A/B on peaks in the calibration mixture as shown on Fig. 2. A is the width in seconds of the part of the peak ahead of the time of the apex at 5 % of peak height, and B equals the width in seconds of the part of the peak after the time of the apex at

(2)

TABLE 4

H

Calibration Mixture

NBP, °F

Relative Density, a 60/60°F

Approximate Volume, %

Typical Thermal Conductivity Response Factors

-44 11 31 82 97 140 156 177 209 231 258 281 319 345 362 421 456 486 519

0.5077 0.5631 0.5844 0.6248 0.6312 0.6579 0.6640 0.6772 0.6882 0.8719 0.7068 0.8657 0.8666 0.7341 0.8646 0.7526 0.7601 0.7667 0.7721

1 3 10 9 7 5 5 5 9 10 5 12 4 3 3 3 2 2 2

1.15 1.14 1.07 1.08 1.03 1.03 1.01 1.07 1.00 0.89 0.98 0.90 0.94 0.99 0.93 1.00 1.02 1.04 1.05

A "Selected Values of Properties of Hydrocarbons and Related Compounds," American Petroleum Institute Project 44, Table 23-2, April 1956. a Necessary if sample contains isopentane and lighter compounds. c Necessary for system evaluation, o Replace 2-methylhexane (2-MeCe) or benzene if the sample contains more than 5 • benzene.

571

t i n D 3710

5 % of peak height. This ratio must not be less than 0.5 nor more than 2.0.

with the known percent. The difference between the calculated and known percentages must not be greater than 0,5.

NOTE 13--A ratio of more than 2.0 is probably due to overloading of the column. This can be corrected by smaller sample size, higher loading of the liquid phase on the packing, or larger diameter column. A ratio of less than 0.5 probably indicates tailing, overloading the detector, or loss of liquid substrate. The column must be changed when tailing becomes excessive. It is possible that the peak shape can be distorted due to a combination of these reasons.

9. Sampling

8.5 Retention Time--The system must be sufficiently repeatable when testing the calibration mixture to obtain peak maxima retention time repeatability ( m a x i m u m difference between duplicate results) of 3 s for isopentane and lighter compounds, if present. The m a x i m u m difference between duplicate results of retention times of the normal pentane and heavier compounds must not be greater than a time equivalent to 3"C (2*F). In addition, the retention time of the apex of the first peak in the calibration mixture should be at least 15 s. 8.6 Polarity--Calculate the boiling point retention time relationship specified in 10.2.2, using only the n-paraffins. Using the observed retention time of the aromatic compounds, calculate their apparent boiling points. Compare the apparent boiling points of the aromatics with their known boiling points. The apparent boiling point of the aromatic compounds must not deviate more than 10*F (6"C) from linearity or normal paraffins in the calibration mixture. 8.7 Area Measurement--The area measurement may be made by an electronic integrator or an analog-to-digital converter in conjunction with a computer. As the run progresses, the amount of material eluted from the column is measured from time zero in time slice areas or counts at specified time intervals. The counts are summed continuously, and the time intervals are equated to equivalent temperatures using the calibration curve generated in 10.2.2. Continue measurement for 2 rain after the apex of the last peak or until the chromatogram returns to a constant baseline at the end of the run. Duplicate results on consecutive runs on the area percent of the compounds in the calibration mixture must not differ by more than 0.1%. 8.7.1 Time intervals need not be uniform throughout the run. However, it is important that all measurement be on the same basis for the blank, calibration, and sample. No interval shall be greater than 0.5 % of the total length of the run. In addition, in order to facilitate the measurement of light ends, the size of the time intervals for the isopentane and lighter compounds should be small enough to allow measurement of their areas and times to peak maxima. NOTE 14--The end of the run can be defined by using the following algorithm: find the time where the rate of change of the chromatographic signal is less than or equal to a specified value (0.05 mV/min and 0.001% of the total area under the chromatogram have been used successfully). Then search for i min before and after that time. The point where the number of counts per slice is at a minimum in that 2-rain period is defined as the end of the run.

8.8 Difference from Calibration Mixture--Multiply the area of each peak in the calibration mixture by the liquid volume response factor calculated in 11.2, and normalize the volume percent of each compound so that the volumes of all compounds heavier than n-butane add up to 100.0. Compare the volume percent of each compound heavier than n-butane 572

9.1 Samplingfrom Bulk Storage: 9.1.1 Cylinder--Refer to Practice D 1265 for instructions on introducing samples into a cylinder from bulk storage. The cylinder should be pressurized with carrier gas to a pressure of at least 345 kPa (50 psi) above the vapor pressure of the sample (Warning--See Note 15). If the sample is to be transferred to another vessel such as a vial with septum, the cylinder must be cooled to a temperature between 32 and 40*F (0 and 4"C). NOTE 15: Warning--Gasoline is extremely flammable. Vapors are harmful if inhaled.

9.1.2 Open Containers--Refer to Practice D 4057 for instructions on introducing samples into open-type containers from bulk storage. Cool the container and its contents to 32 to 40*F (0 to 4"C) before removing any sample from it. 9.2 Sampling from Open-Type Containers--Follow the instructions in Test Method D 323 for transferring material from an open-type container. 10. Procedure

10.1 Blank--After conditions have been set to meet performance requirements, program the column temperature upward to the m a x i m u m temperature to be used. Following a rigorously standardized schedule, cool the column to the selected starting temperature. At the exact time set by the schedule, without injecting a sample, start the column temperature program. Measure and record the area in each time interval from the start ofthe run until the end of the run as specified in 8.7. Make a blank run at least daily. I0.1.1 In order for the blank run to be valid, it must meet the drift requirement specified in 8.3. In addition, no peaks must be found such that the difference in area readings per second in consecutive time intervals be greater than five times the noise. If the noise is not detectable, assume it to be 1 count per second. NOTE 16--The identification of a constant baseline at the end of the run is critical to this test method. Constant attention must be given to all factors that influence baseline stability, such as substrate bleed. NOTe 17--Some gas chromatographs have an algorithm built into their operating software, which causes a mathematical model of the column bleed profile to be stored in memory. This profile is subtracted automatically from the detector signal on subsequent runs to compensate for the column bleed. 10.2 Calibration: 10.2.1 Using the same conditions described in 10.1, inject the calibration mixture into the chromatograph. Record the data in such a manner that retention time of peak maxima and peak area of the individual components are obtained. As noted in 8.7, this can be done by means of a computer or integrator. NOTE 18--When determination of peak maxima and peak area is done by the time slice technique, the followingalgorithms can be used to verify the start of peak, end of peak, and peak maxima: A peak is defined as starting in that time slice in which the rate of change of the chromatographic signal is greater than a specified value (0.05 mV/min and 0.001%/s have been used successfully). This criterion must be confirmed for two consecutive time segments in order to be valid. Once a peak is detected, the end is determined by one oftwo criteria. The first

~

D 3710 versus the c o r r e s p o n d i n g n o r m a l boiling p o i n t in degrees Celsius (or Fahrenheit) as shown in Fig. 4. I f the sample is k n o w n to c o n t a i n less t h a n 5.0 % aromatics, d o not include a r o m a t i c c o m p o u n d s in the retention t i m e calibration curve. NOTE 19--For best precision, the calibration curve should be essentially a linear plot of boiling point versus retention time. In general, the lower the initial boiling point of the sample, the lower will be the starting temperature of the chromatographic column. If the starting temperature is too high, there will be considerable curvature at the lower end of the curve, and loss of precision in that boiling range. Since it is impractical to operate the column so as to eliminate curvature completely at the lower end of the curve where initial boiling points below ambient temperature are encountered, at least one point on the curve should have a boiling point lower than or equal to the initial boiling point of the sample. Extrapolation of the curve at the upper end is more accurate, but for best accuracy, calibration points should bracket the boiling range of the sample at both the low and high ends.

AREA COUNTS

i-i

I

i+l i+2 TIME

FIG. 3

Determination of Time to Peak Maxima

10.2.3 T h e boiling p o i n t retention t i m e calibration curve m u s t be checked at least daily by either the calibration m i x t u r e o r a s e c o n d a r y standard o f k n o w n boiling point characteristics.

applies when there is good resolution between peaks. The peak can be defined as ending when the rate of change of the chromatographic signal is less than the value specified above. The second criterion applies when resolution between peaks is not complete. The first peak ends when, after the apex has passed, the area per time segment reaches a minimum and starts to increase. The retention time of peak maxima can be determined by the following equation, as shown in Fig. 3:

NOTE 20--If peaks in the sample are used as boiling point calibration marks, the calibration mixture need not be run. However, it may prove helpful in establishing identity of peaks in the sample to run the calibration mixture once. Furthermore, precision may be improved in some cases by adding to the sample an n-paraffin, selected so as to be resolved completely from the sample, to serve as an additional boiling point calibration. Plot the retention times of the peaks versus the corresponding atmospheric boiling points to obtain the calibration

tma x = t, + (ti+ I - t,) A,+,/(Ai-~ + A,+O (3) where: tmax = retention t i m e o f peak m a x i m a , ti = time to st~irt o f segment i, 6+, = time to start o f segment i + 1, Ai+l = a r e a o f segment that starts at t;+,, a n d A i _ t = area o f segment that starts at ti_~. F o r systems in which the o u t p u t is in units other t h a n millivolts, a n equivalent measure o f the slope m a y be used.

curve.

10.3 S a m p l i n g : 10.3.1 Using the exact conditions a n d t i m e basis as were used in the b l a n k a n d calibration, inject t h e s a m p l e into the c h r o m a t o g r a p h . Disregarding peaks (if any) before propane,

10.2.2 Plot the retention time o f the m a x i m a o f each peak 60C

50

°~

40

i,o lo

-lo

0

i00

200

300

I 400

I soo

I 600

RETENTION TIME, SECONDS

FIG. 4

Typical Calibration Curve

573

~

~,.~,...=

,~[

D 3710

HORIZONTAL

~)~'SLICEWIDTH

FIG.5 GCDDriftCorrection Ao ffi A,

measure and record the area of each time segment at time intervals as specified in 8.7.

- aa/~ - ( 0 - Oa)

(4)

where: ACi •corrected area of segment i, sample or calibration,

11. Calculation correction is not necessary if the drift is less than 0.5 % as calculated in 8.3. 11.1.1 Correct the blank, calibration, and sample runs for initial offset from zero by subtracting from each time interval the average area of the first five time intervals in the corresponding run. Omit from the average any readings (extraneous peaks) that are more than three times the noise as defined in 8.2. 11.1.2 Correct the calibration and sample for drift by subtracting the corrected area of each time segment of the blank from the corresponding segment of the sample 11.1 D r i f t C o r r e c t i o n - - D r i f t

NOTE 2 l--The corrected area for each time segment is calculated as follows:

A; =uncorrected area of segment i, A~i •area of corresponding segment of blank, O •offset from run, sample or calibration, and OB =offset from blank. 11.1.3 An alternative procedure of correcting for drift and offset is by subtracting a triangular segment of area based on the sample itself as illustrated in Fig. 5. NOTE 22--For the scheme shown in Fig. 5, the corrected area for each time segment is calculated as follows: A o = A, -

o + CA~- A o) \if- to/j

where: =corrected area of segment/, sample or calibration,

Ao

2.0 EXPERIMENTAL MEASUREMENTS

1.8

. /

LEAST SQUARES REGRESSION 1.6 ttl U~

/

SYSTEM NOT OPERATING PROPERLY

1.4

= o

1.2

/" /"

1.0

/" 0.8'

0.4

OF LIGHT ENDS

/

0.2

0.040 ~C3 nCI,604

"~5 .c n~7 .c i ]6

80

I00

.C,o

IS l ....

Jl

,

120

140

160

.c12-c13 .c14 =c15 I

l i 180

It 200

MOLECULAR WEIGHT FIG. 6

Relative Molar Response versus Molecular Weight for n-Paraffins

574

I 220

~

D 3710

TABLE 5 ReportFormat Percent Off

OF

Percent Off

response factor relative to the factor for nC 7 for all compounds iC5 and heavier: Response factor, F, = (V i x Ac)/(V o x Ac,) (6) where: Fi = response factor of the compound, Ac, = corrected area for each pure compound, II,. = volume percent from the calibration mixture, A c o = corrected area of nC 7, and Iio = volume percent of nC 7 in the calibration mixture. 11.2.2 Determine the response factors for propane, isobutane, and n-butane in the following manner. Calculate the relative molar response, RMR, for each of the normal paraffins starting with nC5 as follows:

OF

0.5 (IBP) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

51 52 53 54 55 56 57 58 59 6O 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 99.5 (FBP)

Component

Volume Percent

R M R t = (Ac,

X

mo)/(Aco

×

rni)

(7)

where: RMRi = relative molar response for the compound, mi = mole percent of the compound in the calibration mixture, and mo = mole percent of nC 7 in the calibration mixture. The RMR is a linear function of molecular weight, s The measured RMR's are fit to the linear equation RMR = a M W + b employing the least squares technique. The RMR for propane and n-butane is calculated using the resulting equation. For isobutane, use the R M R measured for n-butane. Calculate response factors for these three components as follows: Response factor, F t = (MWi x RMR o x Deno)/(MW o x RMRi x Den/) (8) where: MWi = molecular weight of the compound, MWo = molecular weight of nC 7, R M R i = relative molar response of the compound, R M R o = relative molar response of nC7, Dent = relative density of the compound, and Deno = relative density of nC 7. Typical response factors along with relative densities are shown in Table 2. NOTE 23--If the concentrations of propane and butane in the calibration mixture are known, differencesnoted between the observed and calculated response factors indicate loss of front-end components. If a fresh calibration mixture is used, these differencescan be indicative of sampling problems. Deviation of the response factors of the heavier components from the straight-line relationship could indicate problems in volatilizing the sample. Possible reasons include injection port temperature being too low, insufficient carrier gas flow, or lack of homogeneity in sampling. Figure 6 illustrates these effects.

n-Ca iso-C 4 n-C 4 iso-C 5

11.2.3 Apply the response factor for each compound in the calibration mixture to the corrected areas of all time intervals in the sample that falls between a point (a) that is halfway between the observed apex of that compound and the observed apex of that compound and the observed apex of the preceding compound, and a point (b) that is halfway between the observed apex of that compound and the observed apex of the succeeding compound. The response factors used may differ according to sample type. For

Ai =uncorrected area of segment i, Ao =average area of last five segments before start of first

peak, Af = area of first segment after end of last peak, ti =time to segment i from beginning of run, to =time to last segment before start of first peak, and tf =time to first segment after end of last peak. 11.1.4 In cases where the calibration is peak-integrated instead of time-sliced, the drift corrections need not be applied. 11.2 R e s p o n s e Factors." 11.2.1 Using the corrected areas from the calibration run and composition of the calibration mixture, calculate the

s Messner, A. E., et al, "Correlation of Thermal Conductivity Cell Response with Molecular Weight and Structure," Analytical Chemtstry. ANCHA, Vol 3 I, No. 2, February 1959, pp. 230-233.

575

~

D 3710 12.2 Report volume percent of isopentane and lighter compounds individually. This provides a more absolute basis for describing commercial gasolines than the IBP. Note 24--Some olefins will be measured with butane and isopentane. See 11.3.4.

commercial gasolines, typical response factors are shown in Table 2. For gasoline blending components containing small amounts of aromatics, such as alkylates, the aromatic response factors should be omitted and only paraffin response factors used. The response factors measured are used until such time as the detectors or columns are changed or there is some reason to suspect that their values are no longer applicable.

13. Precision and Bias 13. I The precision of this test method depends upon the shape of the boiling range distribution curve. Both the repeatability and reproducibility vary with percent recovered and the rate of change of temperature with percent recovered: dT/dV (9) where: T -- temperature, and V = percent recovered. The slopes, dT/dV, are computed from points adjacent to the selected percent recovered points, for example, for 60 %, the temperatures at 58, 59, 61, and 62 %. 13.2 The following criteria should be used for judging acceptability of results. These data were generated from cooperative analyses of gasolines with a wide range of volatilities. 13.2.1 Repeatability--The difference between successive test results obtained by the same operator with the same apparatus under constant operating conditions on identical test material would, in the long run, in the normal and correct operation of the test method, exceed the values shown in Table 1 only in one case in twenty. 13.2.2 Reproducibility--The difference between two single and independent results, obtained by different operators working in different laboratories on identical test material would, in the long run, in the normal and correct operation of the test method, exceed the values shown in Table 1 only in one ease in twenty. 13.3 Bias--Bias cannot be determined since there is no acceptable reference material suitable for determining the bias for the procedure in this test method.

11.3 Calculation of Sample: 11.3.1 For each time segment between the beginning of the first peak and the end of the last peak, multiply the area by the suitable response factor to get volume counts. Divide the cumulative volume counts at the end of each interval by the total volume counts and multiply by 100. This will give the cumulative percent of sample recovered at each interval. 11.3.2 Tabulate the cumulative volume percent recovered at each interval and the retention time at the end of the interval. Using linear interpolation where necessary, determine the retention time associated with 0.5 and 99.5 volume % recovered. These are respectively the initial and final boiling points. Determine the retention time for each volume percent off between 1 and 99. 11.3.3 For each volume percent and its associated retention time, determine the corresponding temperature from the calibration curve (10.2.2). Use linear interpolation between all calibration points. 11.3.4 Identify individually the propane through isopentane peaks by comparing the retention time of each peak to the corresponding retention time in the calibration run. Check to see that the retention time of the apex of the propane, iso-, and normal butane and isopentane peaks is within a time equivalent to 5°F (3"C) of the calibration run. Note any isopentane or lighter component that is apparently absent. Calculate the volume percent of the individual compounds by using the suitable response factors. Include any peaks between normal butane and isopentane with the normal butane peak. 12. Report 12.1 Report the temperature to the nearest I*F (0.5"C) at 1% intervals between 1 and 99 %, and at 0.5 % and 99.5 %. The report format is shown in Table 5. Other formats based on users' needs may also be employed.

14. Keywords 14.1 boiling range distribution; gas chromatography; gasoline; gasoline blending component

576

~

D 3710

ANNEXES

(Mandatory Information) A1.

CALCULATION AND P R E D I C r l O N empirically determined constants AI.3 Predict Test Method D 86 distillation curve from the GCD boiling range distribution curve by an empirical correlation of the general form:

AI. 1 Results obtained by this test method may be used to the vapor pressure of the gasoline sample, including its Reid vapor pressure (RVP) and to predict the Test Method D 86 distillation curve. AI.2 Calculate Reid vapor pressure by the following general equation: R V P = Z aV, ¢-bt. (AI.1)

a,b =

calculate

Percent off, D 86i = Z Aij x Vj where: A o = empirically determined constants, and Vj = percent off by GCD at outpoint j.

where: V i = volume fraction eluted in cut i, t, -- boiling point of cut i, as determined from the calibration curve, and

The American Society for Testing and Materials takes no position respecting the vafidity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard Is subject to revision at any time by the responsible technical committee and must be reviewed every five years and ff not revised, e#her reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend, ff you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103.

577

(A 1.2)

D e s i g n a t i o n : D 3 7 6 0 - 9 3 ~1

Standard Test Method for Analysis of Isopropylbenzene (Cumene) by Gas Chromatography I This standard is issued under the fixed designation D 3760; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year &last reapproval. A superscript epsilon (~) indicates an editorial change since the last revision or rcapproval. E~NOT~--Value in 10.1 corrected editorially in July 1995.

sample of isopropylbenzene. The prepared sample is mixed and analyzed by a gas chromatograph equipped with a flame ionization detector (FID). The peak area of each impurity and the internal standard is measured and the amount of each impurity is calculated from the ratio of the peak area of the internal standard versus the peak area of the impurity. Purity by GC (the isopropylbenzene content) is calculated by subtracting the sum of the impurities found from 100.00. Results are reported in weight percent.

1. Scope 1.1 This test method covers the determination of the purity of isopropylbenzene (cumene) by gas chromatography. 1.2 This test method has been found applicable to the measurement of impurities such as nonaromatic hydrocarbons, benzene, ethylbenzene, t-butylbenzene, n-propylbenzene, alpha-methylstyrene, sec-butylbenzene, and diisopropylbenzene, which are common to the manufacturing process of isopropylbenzene. Limit of detection for these impurities is 10 mg/kg (see 5.1). 1.3 The following applies to all specified limits in this standard: for purposes of determining conformance with this standard, an observed value or a calculated value shall be rounded off "to the nearest unit" in the last right-hand digit used in expressing the specification limit, in accordance with the rounding-off method of Practice E 29. 1.4 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements, see Section 7.

4. Significance and Use 4.1 This test method is suitable for setting specifications on the materials referenced in 1.2 and for use as an internal quality control tool where isopropylbenzene is produced or is used in a manufacturing process. It may also be used in development or research work involving isopropylbenzene. 4.2 This test method is useful in determining the purity of isopropylbenzene with normal impurities present including diisopropylbenzenes. If extremely high boiling or unusual impurities are present in the isopropylbenzene, this test method would not necessarily detect them and the purity calculation would be erroneous. 4.3 Cumene hydroperoxide, if present, will yield decomposition products that will elute in the chromatogram thereby giving incorrect results. 4.4 The nonaromatic hydrocarbons commonly present from the isopropylbenzene manufacturing process will interfere with the determination of benzene when Column A in Table 1 is used. 4.5 The internal standard must be sufficiently resolved from any impurity and the isopropylbenzene peak.

2. Referenced Documents

2.1 ASTM Standards: D3437 Standard Practice for Sampling and Handling Liquid Cyclic Products 2 E 29 Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications3 E 260 Practice for Packed Gas Chromatography 3 E 355 Practice for Gas Chromatography Terms and Relationships 3 2.2 Other Document: OSHA Regulations, 29CFR, paragraphs 1910.1000 and 1910.12004

5. Apparatus 5.1 Gas Chromatograph--Any instrument having a flame ionization detector that can be operated at the conditions given in Table 1. The system should have sufficient sensitivity to obtain a minimum peak height response for 10 mg/kg n-butylbenzene of twice the height of the signal background noise. 5.2 Columns--The choice of column is based on resolution requirements. Any column may be used that is capable of resolving all significant impurities from isopropylbenzene and from the internal standard. The columns described in Table 1 have been used successfully. 5.3 Recorder--Electronic integration is recommended.

3. Summary of Test Method 3.1 A known amount of internal standard is added to a This test method is under the jurisdiction of ASTM Committee D-16 on Aromatic Hydrocarbons and Related Chemicals and is the direct responsibility of Subcommittee DI6.0H on Styrene, Ethylbenzene, and C9 and C~o Aromatic Hydrocarbons. Current edition approved July 15, 1993. Published September 1993. Originally published as D 3760 - 79. Last previous edition D 3760 - 79 (1984). 2 Annual Book of A S T M Standards, Vol 06.04. 3 Annual Book of A S T M Standards, Vol 14.02. 4 Available from Superintendent of Documents, U.S. Government Printing Office, Washington, DC 20402.

6. Reagents and Materials 6.1 Purity of Reagents--Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended 578

~ TABLE Detector Column: Tubing Stationary phase Solid support Film thickness Length, m Diameter, mm Temperatures: Injector, =C Detector, *C Oven: Initial, °C Time 1, rain Final, *C Rate, *C/min Time 2, min Carrier gas Flow rate, mL/min Split ratio Sample size, I~L

1

D 3760

Instrumental Parameters Column A

Column B

Flame Ionization

Flame Ionization

fused silica polyethylene glycol crosslinked 0.25 p. 50 0.32 mm ID

fused silica methyl silicone crosslinked 0.5 I~ 50 0.32 mm ID

275 300

275 300

60 10 175 10 10 hydrogen 1.0 100:1 1.0

35 10 275 5 0 helium 1.0 100:1 1.0

that all reagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, where such specifications are available: Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination. 6.1.1 Internal Standard--Normal Butylbenzene (nBB) is the recommended internal standard of choice. Other compounds may be found acceptable provided they meet the criteria as defined in 4.5 and 6.1. 6.2 Carrier Gas--Chromatographic grade helium or hydrogen is recommended. 6.3 Compressed Air--Chromatographic grade. 6.4 Hydrogen~High purity.

7. Hazards 7.1 Consult current OSHA regulations and suppliers' Material Safety Data Sheets on handling materials listed in this test method. 8. Sampling and Handling 8.1 Sample the material in accordance with Practice D 3437.

0.856 for nBB and 0.857 for cumene, the resulting nBB concentration will be 0.1000 weight %. 10.2 Inject into the gas chromatography an appropriate amount of sample as previously determined according to 6.1 and start the analysis. 10.3 Obtain a chromatograph and peak integration report. Figs. 1 and 2 illustrate a typical analysis of cumene for Columns A and B, respectively. 11. Calculations 11.1 Determine the area defined by each peak in the chromatogram. 11.2 Calculate the percent concentration of the total nonaromatics and each impurity as follows:

(A,XC9

C~ = ~

(i)

(A2)

where: Ci = concentration of component i, weight %, Ai = peak area of component i, A2 = peak area of nBB, C2 = concentration of nBB, weight %. 11.3 Calculate the total concentration of all impurities as follows: C, EC~ (2) where: Ct = total concentration of all impurities. 11.4 Calculate the purity of isopropylbenzene as follows: isopropylbenzene, weight % = 100.000 - C, (3) =

12. Report 12.1 Report the individual impurities to the nearest 0.0001%.

12.2 Report the purity of isopropylbenzene to the nearest 0.001 weight %.

13. Precision and Bias 13.1 Precision:

9. Preparation of Apparatus 9.1 Follow manufacturer's instructions for mounting and conditioning the column into the chromatograph and adjusting the instrument to the conditions described in Table 1 allowing sufficient time for the equipment to reach equilibrium. See Practices E 260 and E 355 for additional information on gas chromatography practices and terminology.

Concentration: Weight %

Repeatability

Benzene Ethylbenzene n-Propylbenzene t-Butylbenzene Alpha-methylstyrene

0.0063 0.0037 0.0175 0.0203 0.0045

0.00024 0.00016 0.00078 0.00085 0.00093

Nonaromatics

0.03 I0

0.003 I0

0.0012 99.9150

0.00041 0.00530

Ortho-Dilsopropylbenzene Cumene

13.1.1 Repeatability data is based on one laboratory's analysis of a single standard sample over a 40-day period. 13.1.2 Reproducibility will be determined. 13.2 Bias--Since there is no accepted reference material suitable for determining the bias for the procedure in this test method for measuring isopropylbenzene purity, bias has not been determined.

I0. Procedure I 0.1 Into a 100-mL volumetric flask, add I00 tiLt of nBB to 99.90 mL of cumene. Mix well. Assuming a density of s Reagent Chemicals, American Chemical Society Specoqcations, American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed by the American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Pc,ale, Dorset, U.K., and the United States Pharmacopeia and National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville, MD. t Editorially corrected.

14. Keywords 14.1 alpha methylstyrene; benzene; butylbenzene; cumene; ethylbenzene; isopropylbenzene; nonaromatic hydrocarbons; propylbenzene; analysis by gas chromatography 579

o 3z6o

CURENE ANALYSIS W DIPB Inst: 14 Ch: Trey J

:F - 0

0

~jCumene

,~ . n-P ropylbenzene

~., t-Butylbenzene

f ~ . , n-Butylbenzene I

4J m-Diisopropylbenzene Non aromatics

/\

v, Benzene

A

MX I s.Butylbenzene

'" 0,0

'

'

'

| 3,0

'

f

'

~

6.0

'

'

'

"

I 9.0

'

'

~" " ~ ' ' l ' ' ' ' ' ~ 1;~,0

'

v

|

,

t5.0

, ~,

',

"[ 18.0

,

,

r

f'~'l

E~.O

MINUTES

FIG. 1 Typical Chmmatogram using Conditions for Column A

580

'

24,0

'

'

{ 27.0

30.0

(~ D 3760 cumene analysts condition ¢2 ;[net: Ch; 0 Tray # 0

~F-O

t

Cumene

n-Propylbenzene

)

t.Butylbenzene m-Diisopropylbenzene

Benzene /& at 15.0 rain

'

30.0

32.0

'

'

I

34.0

'

'

'

'

I

'

36.0

i

,

~

I

i

3B.0

,

,

,

1

. . . .

40.0

I

42.0

'

' ' '

I ' ' 44.0

'

'

I

46.0

'

'

'

'

I ' 48.0

MINUTES FIG. 2

Typical C h r o m a t o g r a m using Conditions for Column B

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and ff not revised, either reepproved or withdrawn, Your commentsare invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful Gonsideration at a meeting of the responsible technical committee, which you may attend, ff you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103.

581

L

' ~ ~ t 50.0

(~[~ Designation: D 3797 - 96 Standard Test Method for Analysis of o-Xylene by Gas Chromatography I This standard is issued under the fixed designation D 3797; the number immediately following the designation indicate~ the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (0 indicates an editorial change since the last revision or reapproval.

1. Scope 1.1 This test method covers the analysis of normally occurring impurities in, and the purity of, o-xylene by gas chromatography. Impurities determined include nonaromatic hydrocarbons, benzene, toluene, p- and m-xylenes, cumene, styrene, and ethylbenzene. 1.2 This test method is applicable for impurities at concentrations from 0.001 to 2.000 % and for o-xylene purities of 98 % or higher. 1.3 The following applies to all specified limits in this standard: for purposes of determining conformance with this standard, an observed value or a calculated value shall be rounded off "to the nearest unit" in the last right-hand digit used in expressing the specification limit, in accordance with the rounding-off method of Practice E 29. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For a specific hazard statement, see Section 7. 2. Referenced Documents

2.1 A S T M Standards: D 3437 Practice for Sampling and Handling Liquid Cyclic Products 2

D 4307 Practice for Preparation of Liquid Blends for Use as Analytical Standards 3 E 29 Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications4 E 260 Practice for Packed Column Gas Chromatograph# E 355 Practice for Gas Chromatography Terms and Relationships 4 E 15 l0 Practice for Installing Fused Silica Open Tubular Capillary Columns in Gas Chromatographs 4 2.2 Other Documents: OSHA Regulations, 29 CFR, paragraphs 1910.1000 and 1910.12005

3. Summary of Test Method 3.1 A known amount of internal standard is added to the sample. A gas chromatograph equipped with a flame ionization detector and a polar-fused silica capillary column is used for the analysis. The impurities are measured relative to the internal standard. To calculate o-Xylene purity subtract the impurities found from 100.00 %. 4. Significance and Use 4.1 This test method is suitable for setting specifications on o-xylene and for use as an internal quality control tool where o-xylene is used in a manufacturing process. It may be used in development or research work involving o-xylene. 4.2 Purity is commonly reported by subtracting the determined expected impurities from 100 %. Absolute purity cannot be determined if unknown impurities are present. 5. Apparatus 5.1 Gas ChromatographymAny gas chromatograph having a flame ionization detector and a splitter injector suitable for use with a fused-silica capillary column may be used, provided the system has sufficient sensitivity to obtain a minimum peak height response of 0.1 mV for 0.010 % internal standard when operated at the stated conditions. Background noise at these conditions is not to exceed 3 I~V. 5.2 Chromatographic Column, fused silica capillary, 60-m long, 0.32-ram inside diameter, internally coated to a 0.5-~tm thickness with a bonded (cross-finked) polyethylene glycol. Other columns may be used after it has been established that such column is capable of separating all major impurities and the internal standard from the o-xylene under operating conditions appropriate for the column. 5.3 Recorder, electronic integration with tangent capabilities (required). 5.4 Microsyringes, 10-ttL, and 50-ttL. 5.5 Volumetric Flask, 50-mL. 6. Reagents and Materials 6.1 Carrier Gas, hydrogen or helium, chromatographic grade. 6.2 Compressed Air, oil free. 6.3 Hydrogen, chromatographic grade. 6.4 Nitrogen, chromatographic grade. 6.5 Pure compounds for calibration shall include nnonane (Note l), toluene, styrene, ethylbenzene, p-xylene, m-xylene, o-xylene, isopropylbenzene, isooctane, (Note 2), n-octane (Note 2), n-undecane (Note 2), of a purity not less than 99 %. If the purity of the calibration compounds is less than 99 %, the concentration and identification of impurities must be known so that the composition of the final weighed

t This test method is under the jurisdiction of ASTM Committee D--16 on Aromatic Hydrocarbons and Related Chemicals and is the direct responsibility of Subcommittee DI6.0A on Benzene, Toluene, Xylenes, Cy¢lohexane, and Their Derivatives. Current edition approved Jan. 10, 1996. Published March 1996. Originally published as D 3797 - 79. Last previous edition D 3797 - 95. 2 Annual Book of ASTM Standards, Vol 06.04. 3 Annual Book of A S T M Standards, Vol 05.02. 4 Annual Book of ASTM Standards, Vol 14.02. 5 Available from Superintendent of Documents, U.S. Government Printing Office, Washington, DC 20402.

582

tl~) O 3797 TABLE 1

blends can be adjusted for presence of the impurities. NOTE l--n-nonane represents the nonaromaticin a sample. NOTE 2--Any of these compounds may be used as an internal standard provided it elutes free of contamination.

Instrument Parameters

Carder Carder gas flow rate at 1100C, mr./rain Detector Detector temperature, °C Injection port temperature, *C Hydrogen flow rate, mL/min

7. Hazards

Airflow rate, mL/mln Make-up gas Make-up gas flow rate, mL/min Split flow, ml../mln Column temperature program: Initial temperature, *C Initial time, rain Programming rate, *C/rain Final temperature, *C Chart speed, cm/min Sample size, IxL

7.1 Consult current OSHA regulations, local regulations, and supplier's Material Safety Data Sheets for all materials used in this test method. 8. Sampling

8.1 Guidelines for taking samples from bulk are given in Practice D 3437.

helium 1.2 flame ionization 240

230 30 275

nitrogen 23 150 70 24 20 210 1 0.6

9. Calibration

9.1 Prepare a synthetic mixture in accordance with Practice D 4307 from pure hydrocarbons with all of the aromatic compounds present in the sample to be analyzed containing approximately 98.0 weight % o-xylene and the expected significant impurities at their expected concentration. Suggested composition is given in weight percent, o-Xylene of a purity not less than 99 weight % must be used in preparing the calibration mixture. The pure material itself must be analyzed and corrections made in the composition of the calibration blend as required. Sample the material in accordance with Practice D 3437. o-xylene toluene p-xylene m-xylene ethylbenzene isopropyl benzene n-nonane

benzene styrene

manufacturer of the gas chromatograph and Practices E 355 and E 1510. 10.2 Fill a 50-mL volumetric flask to the mark with test specimen. With a microsyringe, add 30 ~tL of the standard. Mix well. Using a density of 0.692 for/so-octane and 0.880 for o-xylene, this solution will contain 0.0472 weight % internal standard. 10.3 Inject 0.6 IxL of solution into the gas chromatograph and obtain the chromatogram. A typical chromatogram is shown in Fig. 1.

98.25 % 0.2 % 0.2 % 0.4 % 6.2 % 0.3 % 0.2 % 0.2 % 0.05 %

11. Calculation 11.1 Measure the areas of all peaks, including the internal standard, except for the o-xylene peak. 11.2 Sum all the peaks eluting between the isooctane and toluene peaks. Identify this sum as nonaromatic hydrocarbons plus benzene. 11.3 Calculate the weight percent of the individual impurities, C i to the nearest 0.001% as follows:

9.2 Analyze the o-xylene used in preparing the calibration blend as described in 10.2 and 10.3. Calculate the purity of the stock o-xylene as shown in 11.3, using an assumed response factor of 1.00 for each impurity. This will verify that the o-xylene used in preparing this test method is 99 weight % or better. 9.3 Analyze the calibration blend as described in 10.3. 9.4 Calculate response factors as follows: R; =

c,

c,

--

IS (A~) A,(Rd

(2)

where: I S = internal standard, weight %, A i = area of impurity, R,~ = response factor for impurity, and A, = area of internal standard. 11.4 Use the response factor determined for n-nonane for all the nonaromatic hydrocarbon plus benzene peaks. 11.5 Calculate the purity of the o-xylene by subtracting the sum of the impurities from 100.00.

(1)

where: response factor for impurity relative to internal standard, A i =- area of impurity peak in calibration blend, A b = area of impurity in the stock o-xylene, c,= concentration of internal standard, weight %, area of internal standard peak in calibration blend, Asi Ash area of internal standard peak in stock o-xylene, and c,= concentration of impurity, weight, %. 9.5 Calculate response factors to the nearest 0.001. Ri =

12. Report 12.1 Report the following information: 12.1.1 The concentration of each impurity to the nearest 0.001 weight %, and 12.1.2 The purity of o-xylene to the nearest 0.01 weight %.

=

=

13. Intermediate Precision and Bias 6

13.1 P r e c i s i o n - - T h e following criteria should be used to

10. Procedure

10.1 Install the chromatograph column and establish stable instrument operation at the operating conditions shown in Table 1. Refer to instructions provided by the

e Supporting data are available at ASTM Headquarters. Request Research Report D 16 - 1019.

583

~

D 3797

4.765

5.298 6.289 7.128

2

8.152

3

11

9.

267 10.169

5,6,7

13.311 13.714

14.839 14.368 IS.esl

I0

PEAK IDENTIFICATIONS:

19.328

I 22.112

1. /so-octane 2. n-Nonane 3. Benzene 4. Toluene 5. Ethylbenzene 6. p-Xylene 7. m-Xylene 8. Cumene 9. o-Xylene 10. Styrene 11. Non-aromatics plus benzene

FIG. 1 TypicalChrematogram(SeeTable1)

584

8 9

({~ O 3797 TABLE 2

judge the acceptability (95 % probability level) of the results obtained by this test method. The criteria were derived from a round robin between nine laboratories. The data were run over two days using different operators. 13.1.1 Intermediate Precision formerly called Repeatability--Results in the same laboratory should not be considered suspect unless they differ by more than the amount shown in Table 2. 13.1.2 ReproducibilityDThe results submitted by two laboratories should not be considered suspect unless they differ by more than the amount shown in Table 2. 13.2 Bias--No statement is made about bias since no acceptable reference material and value are available.

Component Styrene Cumene m-Xylene p-Xylene Ethylbenzane Toluene Benzene Nonaromatlcs o-Xylene

Intermediate Precision

Concentration weight ~ 0.005 0.221 1.066 0.192 0.011 0.063 0.091 0.088 98.261

Intermediate PreoJston 0.001 0.014 0.058 0.039 0.001 0.004 0.005 0.026 0.10

14. Keywords 14.1 gas chromatography;

o-xylene;purity

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend, ff you feel that your comments have not received a fair hearing you should make your view8 known to the ASTM Committee on Standards, 100 Barr Harbor Drive, West Conshohockan, PA 19428.

585

Reproducibility 0.002 0.057 0.26 0.066 0.005 0.017 0.026 0.065 0.42

(1~

Designation: D 3798 - 96b

Standard Test Method for Analysis of p-Xylene by Gas Chromatography 1 This standard is issued under the fixed designation D 3798; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsiion (0 indicates an editorial change since the last revision or reapproval.

analyzed by a gas chromatograph equipped with a flame ionization detector (FID). The peak area of each impurity and the internal standard is measured. The amount of each impurity is calculated from the ratio of the peak area of the internal standard versus the peak area of the impurity. Purity by GC (the p-xylene content) is calculated by subtracting the sum of the impurities found from 100.00. Results are reported in weight percent.

1. Scope 1.1 This test method covers the determination of known hydrocarbon impurities in, and the purity ofp-xylene by gas chromatography (GC). It is generally meant for the analysis of p-xylene of 99 % or greater purity. Impurity concentrations that can be measured range from 0.001 to 1.000 weight 7o. 1.2 The following applies to all specified limits in this test method: for purposes of determining conformance with this test method, an observed value or a calculated value shall be rounded off 'to the nearest unit' in the right-hand digit used in expressing the specification limit, in accordance with the rounding-off method of Practice E 29. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For a specific hazard statement, see Section 8.

4. Significance and Use 4.1 This test method is suitable for setting specifications on p-xylene and for use as an internal quality control tool where p-xylene is produced or is used in a manufacturing process. It may also be used in development or research work involving p-xylene. It is generally appfied to determining those commonly occurring impurities such as nonaromatic hydrocarbons, benzene, toluene, ethylbenzene, m-xylene, o-xylene, and cumene (isopropylbenzene). 4.2 Purity is commonly reported by subtracting the determined expected impurities from 100.00. However, a gas chromatographic analysis cannot determine absolute purity if unknown components are contained within the material being examined. Refer to Specification D 5136 for deterraining other chemical and physical properties ofp-xylene.

2. Referenced Documents

2.1 ASTM Standards: D 3437 Practice for Sampling and Handling Liquid Cyclic Products2 D 5136 Specification for High Purity p-Xylene2 E 29 Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications3 E 260 Practice for Packed Column Gas Chromatography3 E 355 Practice for Gas Chromatography Terms and Relationships 3 E 691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method 3 E 1510 Practice for Installing Fused Silica Open Tubular Capillary Columns in Gas Chromatographs 3 2.2 Other Document: OSHA Regulations, 29 CFR, paragraphs 1910.1000 and 1910.12004

5. Interferences 5.1 The internal standard chosen must be sufficiently resolved from any impurity and the p-xylene peak. Refer to 7.4.1. 6. Apparatus 6.1 Gas Chromatograph--Any chromatograph having a flame ionization detector that can be operated at the conditions given in Table 1. The system should have sufficient sensitivity to obtain a minimum peak height response for a 0.001 weight % impurity twice the height of the signal background noise. 6.2 Columns--Different columns have been found satisfactory, depending on the purity of the p-xylene to be analyzed. 6.2.1 p-Xylene Range from 99.0 to 99.8 %--Both capillary and packed columns have been found satisfactory. The column must give satisfactory separation of the internal standard from p-xylene and the impurity peaks. Complete separation of ethylbenzene and m-xylene from p-xylene is difficult and can be considered adequate if the distance from the baseline to the valley between peaks is not greater than 50 % of the peak height of the impurity. Table 1 contains a description of two columns that have been found satisfactory. 6.2.2 p-Xylene Range 99.8 7o and Greater--Only capillary columns have been found satisfactory. Complete separation

3. Summary of Test Method 3.1 A known amount of an internal standard is added to a specimen of p-xylene. The prepared specimen is mixed and This test method is under the jurisdiction of ASTM Committee D-16 on Aromatic Hydrocarbons and Related Chemicals and is the direct responsibility of Subcommittee DI6.0A on Benzene, Toluene, Xylenes, Cyclohexane and Their Derivatives. Current edition approved Dec. 10, 1996. Published February 1997. Originally published as D 3798 - 79. Last previous edition D 3798 - 96a. 2 Annual Book of A S T M Standards, Vol 06.04. 3 Annual Book of A S T M Standards, Vol 14.02. Available from Superintendent of Documents, U.S. Government Printing Office, Washington, DC 20402.

586

(~ D 3798 TABLE 1

A

B

Column: Tubing Stationary phase

fused sfl=ce crosslinked

Concentration, weight % Solid support Mesh size Film thickness, [.t Length, m Inside diameter, mm Carrier gas: Flow rate, mL/min Split ratio

polyethylene glycol not applicable not applicable 0.25 50 0.32 helium 1.0 100:1

stainless steel diisodecylphthalate Bentone 34 A 3.5 %/3.5 % flux-calcined diatomite a 60 to 80 not applicable 6.1 3.2 helium 30 not applicable

200 200 60

200 200 60

n-undecane

n-octane

Temperature, °C: Inlet Dectector Column Intemal Standard

TABLE 2

Instrument Conditions for p-Xylene Analysis

,* The sole source of supply of the material known to the committee at this time is Bentone 34, available from National Lead Co. If you are aware of alternative suppliers, please provide this information to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, 1 which you may attend.

of ethylbenzene and m-xylene from p-xylene is difficult and can be considered adequate if the distance from the baseline to the valley between peaks is not greater than 50 % of the peak height of the impurity. It is important that tangential skimming is employed. Table I A contains a description of one column that has been found satisfactory. 6.3 RecordermElectronic integration is required. Tangent skimming capabilities are required because of the difficulty in fully separating impurities from p-xylene. 6.4 Microsyringe, 100-1xLcapacity. 6.5 VolumetricFlask, 100-mL capacity.

Component

p-Xylene (see 7.2.1) Toluene Ethylbenzene

m-Xylene o-Xylene Isopropylbenzene n-Nonane

Typical Calibration Blend

mL

Density A

Weight, g

Concentration, weight %

572.0 0.058 0.579 1.163 0.116 0.058 0.070

0.857 0.862 0.863 0.860 0.876 0.857 0.714

490.2 0.050 0.500 1.000 0.102 0.050 0.050

99.64 0.010 0.102 0.203 0.021 0.010 0.010

A Numbers are density in grams per millilitre at 25"C.

as indicated by gas chromatography. 7.3 Carrier GasnChromatographic-grade nitrogen, helium, or hydrogen have been found satisfactory for the p-xylene range from 99.0 to 99.8 %. However, only helium or hydrogen have been found satisfactory for the p-xylene range of 99.8 % and greater. 7.4 Pure Compounds for Calibration, shall include mxylene, o-xylene, toluene, ethylbenzene, isopropylbenzene (cumene), and n-nonane. The purity of all reagents should be 99 % or greater. If the purity is less than 99 %, the concentration and identification of impurities must be known so that the composition of the standard can be adjusted for the presence of the impurities. 7.4.1 Internal Standard--n-Undecane (NCI 1) is the recommended internal standard of choice for Conditions A and n-octane (NC8) for Conditions B in Table 1. However, other compounds may be found acceptable provided they meet the criteria as defined in Section 5 and 7.4.

8. Hazards 8.1 Consult current OSHA regulations, supplier's Material Safety Data Sheets, and local regulations for all materials used in this test method.

7. Reagents

7.1 Purity of Reagent--Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, where such specifications are available. 5 Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination. 7.2 High Purity p-Xylene (99.99 % or greater purity)-Most p-xylene is available commercially at a purity less than 99.9 weight %, but can be purified by recrystaUization. To prepare 2 qt of high-purity p-xylene, begin with approximately 1 gai of reagent-grade p-xylene and cool in an explosion-proof freezer at - 1 0 -4- 10*C until approximately I/2 to 3/4 of the p-xylene has frozen. This should require about 5 h. Remove the sample and decant the liquid portion. Allow the p-xylene to thaw and repeat the crystallization step on the remaining sample until the p-xylene is free of contamination

9. Sampling 9.1 Sample the material in accordance with Practice D 3437. 10. Preparation of Apparatus 10.1 The method used to prepare packed columns is not critical provided that the finished column produces the desired separation. 10.2 Follow the manufacturer's instructions for mounting and conditioning the column into the chromatograph and adjusting the instrument to the conditions described in Table 1. Allow sufficient time for the equipment to reach equilibrium. See Practices E 260, E 355, and E 1510 for additional information on gas chromatography practices and terminology. 11. Calibration 1 I. 1 Prepare synthetic mixtures ofp-xylene with representative impurities on a weight basis. Weigh each hydrocarbon impurity to the nearest 0.0001 g. Refer to Table 2 for an example of a typical calibration blend, n-Nonane will represent the nonaromatic fraction.

5 Reagent Chemicals, American Chemical Society Specifications, American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed by the American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Peele, Dorset, U.K., and the United States Pharmacopeia and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.

587

~

D 3798

J|

N--X~

?

mmNCli

i2.44 ~

E-.SEICZ t5.49 ~ ~

O-

48

CIjUI~I

.

7.0

A

9.0

1t.0

13.0

15.0

17.0

lg.0

21.0

23.0

~.0

MINUTES

FIG. 1 p-XyleneAnalyMs IMng Conditlons ,4 In Table I

12. Procedure

11.2 Using the exact weight, or alternatively the exact volumes and densities (see Table 2), calculate the weight % coneentration for each impurity in each calibration blend of ! 1.1. 11.3 Into a 100-mL volumetric flask, add 100.0 pL of n-undecane to 99.90 mL of the calibration blend; mix well. Assuming a density of 0.861 g/mL for the p-xylene blend and 0.740 g/mL for NCI 1, the resulting NCI 1 concentration will be 0.086 weight %. 11.4 Inject the resulting solution from 11.3 into the chromatograph. A typical chromatogram is illustrated in Fig. I. 11.5 Determine the response factor for each impurity relative to NCI 1 by measuring the area under each peak and calculate as follows:

12.1 Fill 100-mL volumetric flask half full with sample. Pipet 100.0 pL of internal standard into a 100-mL volumetric flask and dilute to the mark with the sample to be analyzed. Mix well. 12.2 Depending upon the actual chromatograph's operating conditions, charge an appropriate amount of specimen into the instrument. 12.3 Measure the area of all peaks except p-xylene. Measurements on the specimen must be consistent with those made on the calibration blend. Sum and report the nonaromatic fraction as a total area. A poorly resolved peak, such as m-xylene will often require a tangent skim from the neighboring peak. Make consistent measurements on the specimen and calibration chromatograms for tangents or poorly resolved peaks. A typical chromatogram is shown in Fig. 1.

Re- (Cs)(A,) _

where: R i -- response factor for impurity i relative to the internal standard, Ai = peak area of impurity i, As -- peak area of the internal standard, Cs = concentration of the internal standard, weight %, and C~ = concentration of impurity i, as calculated in 11.3, weight %. 11.6 Calculate the response factors to the nearest 0.001.

13. Calculation

13.1 Calculate the amounts of each individual impurity. Total the concentration of all impurities. Calculate the p-xylene purity by the difference from 100.00. 13.2 Calculate the impurities as follows: 588

({~) D 3798 (A,)(R,) (C.) (A~) c,= ~c,

Intermediate Precision and Reproducibility for Internal Standard Where p-Xylene Range is from 99.0 to 99.8 %

TABLE 3

C,=

where: Ct = total concentration of all impurities, weight %. 13.3 Calculate the purity ofp-xylene, P, in weight percent as follows: P

=

1oo.oo

-

NOTE--This data was calculated after the removal of outUers using Practice E 891. Variation of the p-xylene purity was determined from the variation of the calculated total purity.

c,

14. Report 14.1 Report the following information: 14.1.1 Individual impurities to the nearest 0.001 weight %, 14.1.2 For concentrations of impurities less than 0.001 weight %, report as <0.001 weight %, and consider as 0.000 in summation of impurities, 14.1.3 The total impurities to the nearest 0.01 weight %, and 14.1.4 p-Xylene content to the nearest 0.01 weight %. 15. Precision and Bias6 15.1 The following criteria should be used to judge the acceptability (95 % confidence level) of results obtained by this test method. The criteria for p-xylene from 99.0 to 99.8 weight % were derived from a round robin among 13 laboratories. The data were run on 2 days using different operators and three samples ranging in concentration from 99.0 to 99.8 weight %. The criteria for p-xylene from 99.8 and greater weight % were derived from a round robin among seven laboratories. The data were run on two days using different operators and two samples ranging in concentration from 99.8 to 99.9+ weight %. Results of the interlaboratory study were calculated using Practice E 691.

15.1.1 Intermediate Precision, (formerly Repeatability)m Results in the same laboratory should not be considered suspect unless they differ by more than _ the amount shown in Table 3 or Table 4 depending on the p-xylene concentration. On the basis of test error alone, the difference between two test results obtained in the same laboratory on the same material will be expected to exceed this value only about 5 % of the time. 15.1.2 Reproducilibity--Results submitted by each of two

Component

Concentration Weight •

p-Xylene Noneromatics Toluene Ethylbenzane m-Xylene o-Xylene

99.510 0.030 0.014 0.110 0.250 0.100

Intermediate Precision 0.026 0.014 0.003 0.011 0.018 0.011

Reproducibility 0.093 0.058 0.009 0.029 0.043 0.020

TABLE 4 Intermediate Precision end Reproducilibity for Intemel Standard Where p-Xylene Range is 99.8 % or Greater NOTE--This data was calculated after the removal of outliers using Practice E 691. Variation of the p-Xylene purity was determined from the variation of the calculated total purity. Component

Concentration Weight ~

p-Xylene Noneromatics Toluene Ethylbenzene m-Xylene o-Xylane

99.885 0.007 0.007 0.017 0.061 0.024

Intermeidate Precision 0.046 0.012 0.003 0.006 0.028 0.005

Reproducibility 0.055 0.013 0.004 0.011 0.038 0.010

laboratories should not be considered suspect unless they differ by more than the amount shown in Table 3 or Table 4 depending on the p-xylene concentration. On the basis of test error alone, the difference between two test results obtained in different laboratories on the same material will be expected to exceed this value only about 5 % of the time. 15.2 Bias--The results from the analysis by 13 different laboratories of a gravimctricaily prepared blend of p-xylene in the concentration range from 99.0 to 99.8 weight % indicates this procedure does not contain a measurable amount of bias nor systematic error that could contribute to a difference between a population mean and the accepted true value. Bias for p-xylene in the concentration range of 99.8 and greater weight % has not been determined. 16. Keywords

16.1 1,4-dimethyl benzene; gas chromatography; pXylene

6 Supporting data are available from ASTM Headquarters. Request RR:DI61011.

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend, ff you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 100 Barr Harbor Drive, West Conshohockan, PA 19428.

589

(~l~ Designation: O 3961-89 (Reapproved 1993)'1 Standard Test Method for Trace Quantities of Sulfur in Liquid Aromatic Hydrocarbons by Oxidative Microcoulometry 1 This standard is issued under the fixeddesignationD 3961; the numberimmediatelyfollowingthe designationindicatesthe yearof original adoptionor, in the caseof revision,the yearof last revision.A numberin parenthesesindicatesthe yearof last reapproval.A superscriptepsilon(e) indicatesan editorialchange sincethe last revisionor reapproval. elNoTEIKeywords were added editoriallyin July 1993.

3.3 These microequivalents of triiodide (iodine) are equal to the number of microequivalents of titratable sample ion entering the titration cell. The unknown sample is compared to a known sample and the appropriate calculations made to report the sulfur concentration. It is important that the sulfur content of the known sample be within a factor of two of the unknown sample.

1. Scope 1.1 This test method covers the determination of sulfur in the range from 0.5 to 100 mg/kg in aromatic hydrocarbons. 1.2 The test method may be extended to higher sulfur concentrations by appropriate dilution.

1.3 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific

4. Significance and Use

4.1 Total sulfur concentrations are typically required for benzene, toluene, and xylenes used as chemical intermediates in solvents. This test may be used for both final product inspections and process control. 4.2 This test method is believed to be applicable in the presence of total halide concentrations of up to 10 times the sulfur concentration and total nitrogen concentrations of up to 1000 times the sulfur concentration. 4.3 This test method is not applicable in the presence of total heavy metal concentrations (for example, Ni, V, Pb, etc.) in excess of 500 mg/kg.

hazard statements, see Section 7 and Note 2. 2. Referenced Document

2.1 A S T M Standards: D 329 Specification for Acetone 2 D 3437 Practice for Sampling and Handling Liquid Cyclic Products 2 2.2 Other Document: 3 OSHA Regulations, 29 CFR, paragraphs 1910.1000 and 1910.12003

NoTe l--To attain the quantitative accuracy of which method is capable, stringent techniques must be employed to prevent all possible sources of contamination.

3. Summary of Test Method

3.1 A liquid sample is injected into a combustion tube maintained at about 800"C having a flowing stream of gas containing about 80 % oxygen and 20 % inert gas (for example, nitrogen, argon, etc.). Oxidative pyrolysis converts the sulfur to sulfur dioxide which then flows into a titration cell where it reacts with triiodide ion present in the electrolyte. The triiodide thus consumed is coulometrically replaced and the total electrical work required to replace it is a measure of the sulfur present in the sample injected. 3.2 The reaction occurring in the titration cell as sulfur dioxide enters is:

5. Apparatus 4

5.1 Pyrolysis Furnace--The sample shall be pyrolyzed in an electric furnace having at least two separate and independently controlled temperature zones, the first being an inlet section that can maintain a temperature sufficient to volatilize all the organic sample. The second zone shall be a pyrolysis section that can maintain a temperature sufficient to pyrolyze the organic matrix and oxidize all the organically bound sulfur. A third outlet temperature zone is required. A flow diagram of the complete instrument is shown in Fig. 1. 5.l.l Pyrolysis furnace temperature zones for hydrocarbons should be variable as follows: Inlet zone up to at least 700"C Center pyrolysiszone up to at least 900"C Outlet zone up to at least 800"C

I3- + SO2 + H20 --* SO3 + 3I- + 2H + The triiodide ion consumed in the above reaction is generated coulometrically thus: 3I- ~ 13- + 2e' This test method is under the jurisdiction of ASTM CommitteeD-16 on AromaticHydrocarbonsand RelatedChemicalsand is the direct responsibilityof SubcommitteeDI6.0E on InstrumentalAnalysis. Current edition approvedNov. 24, 1989. PublishedJanuary 1990. Originally published as D 3961 - 80. Lastpreviousedition D 3961 - 80 (1985)et. 2AnnualBookofASTMStandards,Vol 06.04. 3Available from Superintendent of Documents, U.S. GovernmentPrinting Office,Washington,DC 20402. 590

4 The apparatusdescribedin 5.1 to 5.5 inclusiveis similarin specificationsto equipmentavailablefromRosemontAnalyticalDivision,Dohrmann,SantaClara, CA 95052. For furtherdetailed discussions,in equipment,see: Preprints-Division of PetroleumChemistry,AmericanChemicalSociety,Vol 1, No. 3, Sept. 7-12, 1969, p. B232,~Determinationof Sulfur, Nitrogen,and Chlorinein Petroleumby Microcoulometry,"by HarryV. Drnshel.

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NOTE 2: Caution--Excessive speed will decouple the stirring bar, causing it to rise in the cell and damage the electrodes.The creation of a slight vortex is adequate. 5.4 Microcoulometer, having variable attenuation, gain control, and capable of measuring the potential of the sensing-reference electrode pair, and comparing this potential with a bias potential, amplifying the potential difference to the working-auxiliary electrode pair so as to generate a titrant. Also the microcoulometer output voltage signal shall be proportional to the generating current. 5.5 Recorder, having a sensitivity to at least 0.1 mV/in. with chart speeds of ~/2to 1 in./min (13 to 25 mm/min). Use of a suitable electronic or mechanical integrator is recommended but optional. 5.6 Sampling Syringe--A microlitre syringe of 10-~tL capacity capable of accurately delivering 1 to 10-~tL of sample into the pyrolysis tube. 3-in. by 26-gage (76 by 0.405-mm) needles are recommended to reach the inlet zone of the pyrolysis furnace. NOTE 3--Since care must be taken not to overload the pyrolyzing capacity of the tube by too fast a sample injection rate, means should be provided for controllingthe sample addition rate (0.1 to 0.2 IxL/s).

6. Reagents and Materials

6.1 Purity of Reagents--Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, where such specifications are available? Other grades may be used provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination. 6.2 Purity of WatermThe water used in preparing the cell electrolyte should be demineralized, distilled, or both. Water of high purity is essential. NOTE 4mDistilled water obtained from all borosilicateglass still, fed from a demineralizer, has proven satisfactory. 6.3 Acetic Acid (sp gr 1.05)--Concentrated acetic acid (CH3COOH). 6.4 Acetone (CH3COCH3), Specification D 329. 6.5 Argon, Helium, or Nitrogen, high-purity grade (HP) (Note 5), used as carrier gas. NOTE 5--High-purity grade gas has a minimum purity of 99.995 %. 6.6 Cell Electrolyte Solution--Dissolve 0.5 g of potassium iodide (KI) and 0.6 g of sodium azide (NAN3) in approximately 500 mL of high-purity water, add 5 mL of acetic acid (CH3COOH), and dilute to 1000 mL. 6.7 Gas Regulators--Two.stage gas regulators must be used on the reactant and carder gas. 6.8 Hydrofluoric Acid (HF), l + 1 mixture with water. The exact mix is not critical since it is used in cleaning equipment. The use of HF should be minimized because of safety considerations.

6.9 Iodine (I), 20-mesh or less, for saturated reference electrode. 6.10 Isooctane (Note 6) ( 2,2, 4-trimethyl pentane). NOTE 6 --Pesticide test grade such as Mallinckrodt "Nanograde"

isooctane has been found satisfactory.Reference fuel 140 is acceptable

as long as the sulfur concentration is below 10 % of the samples being analyzed. An optional step is to percolate the sample through silicagel. NOTE 7--The most reliable solventis a sulfur-freeform of the sample type to be analyzed.Alternatively,use a high-purityform ofcyclobexane boiling point 80"C (176"F). It is desirable that the solvent has some structural similarityto the sample. NOTE 8--The analyst may choose other sulfur compounds for standards appropriate to sample boiling range and sulfur type which cover the concentration range of sulfur expected. It is imperative, however, that the sulfur content of the standard is within a factor of 2 of the sulfur content of the sample.

6.11 Oxygen, high-purity grade (HP) (Note 5), used as the reactant gas.

6.12 Potassium Iodide (K.I), fine granular. 6.13 Sodium Azide (NAN3), fine granular. 6.14 Di.n-butyl Sulfide (CH3CH2CH2CH2)2S or dibutyl disulfide (CH3CH2CH2CH2S)2.

6.15 Sulfur, Standard Stock Solution (approximately 300 ppm)--Weigh accurately 0.5000 g ofdi-n-butyl sulfide into a tared 500-mL volumetric flask. Dilute to the mark with isooctane and reweigh. D x 0.2187 × 106 S, mg/mg = B where: D ffi di-n-butyl sulfide, g, and B = (di-n-butyl sulfide + solvent), g. 6.16 Sulfur Standard Solutions should be prepared at sulfur concentrations within a factor of two of the unknown. For example, for approximately 30 ppm, pipet 10 mL of sulfur stock solution (reagent 6.15) into a 100-mL volumetric flask and dilute to volume with isooctane. 7. Hazards 7.1 Consult the current OSHA regulations and supplier's Material Safety Data Sheets for all materials used in this test method. 7.2 Aromatics are considered hazardous materials. Practice sufficient care to limit the exposure to aromatics so that the OSHA threshhold limit values are not exceeded. In addition, other chemicals such as hydrofluoric acid and sodium azide are used in the method.

8. Sampling 8.1 Consult guidelines for taking samples from bulk in Practice D 3437. 9. Preparation of Apparatus 9.1 Carefully insert the quartz pyrolysis tube in the pyrolysis furnace and connect the reactant and carrier gas lines. 9.2 Add the electrolyte solution to the titration cell and flush several times. Maintain an electrolyte level of I/s to 1/4 in. (3.2 to 6.4 ram) above the platinum electrodes. 9.3 Place the heating tape on the inlet of the titration cell. 9.4 Place the titration cell on the magnetic stirring device and connect the cell inlet to the outlet end of the pyrolysis

s "Reagent Chemicals, American Chemical Society Specifications," Am. Chemical Sot., Washington, DC. For suggestions on the testing of reagents not listed by the American Chemical Society, see "Reagent Chemicals and Standards," by Joseph Rosin, D. Van Nostrand Co., Inc., New York, NY, and the "United States Pharmacopeia."

592

i~) D 3961 TABLE 2

tube. Position the platinum foil electrodes (mounted on the movable cell head) so that the gas inlet flow is parallel to the electrodes with the generator anode adjacent to the generator cathode, Assemble and connect the coulometer and recorder (integrator optional) as designed or in accordance with the manufacturer's instructions. 9.4.1 Turn the heating tape on. 9.5 Adjust the flow of the gases, the pyrolysis furnace temperature, titration cell, and the coulometer to the desired operating conditions. Typical operational conditions are given in Table !.

Sample Type Benzene Cyclohexane

Isooctene Styrene

TABLE 1

Coulometer: Bias voltage, mV Gain mg/kg $ 100 50 10 3-5 1 Recorder Sample injection rate

Sulfur Compound disbutyl sulfide dibutyl sulfide dlbutyl sulfide elemental sulfur

even rate of about 0.1 to 0.2 pL/s. If a microlitre syringe is used with an automatic injection adapter, calibrate the injection rate (volume/pulse) to deliver 0.1 to 0.2 pL/s. 10.5 Repeat the measurement of each calibration standard at least three times. It has been observed that artificially high concentrations have been reported when low sulfur samples follow high sulfur samples. Isooctane samples can be used to confirm the absence of sulfur in the equipment.

10. Calibration and Standardization 10.1 Prepare a series of calibration standards covering the range of sulfur concentration expected. Follow instructions in 6.15, 6.16, or dilute to appropriate level with isooctane. It is important that the sulfur concentration of the standard to be used be within a factor of two of the sulfur concentration of the sample. 10.2 Adjust the operational parameters as shown in Table 1. 10.3 The sample size can be determined either by volume or by mass. The sample size should be 80 % or less of the syringe capacity. 10.3.1 Volumetric measurement can be obtained by filling the syringe with about 7 pL of sample, being careful to eliminate bubbles, retracting the plunger so that the lower liquid meniscus falls on the l-pL mark, and recording the volume of liquid in the syringe. After the sample has been injected, again retract the plunger so that the lower liquid meniscus falls on the l-pL mark, and record the volume of liquid in the syringe. The difference between the two volume readings is the volume of sample injected. 10.3.2 Alternatively, the sample injection device may be weighed before and after the injection to determine the amount of sample injected. This method provides greater precision than the volume delivery method, provided a balance with a precision of +0.00001 g is used. 10.4 Insert the syringe needle through the inlet septum up to the syringe barrel and inject the sample or standard at an

NOTE 9--Not all of the sulfur in the sample comes through the furnace as titratable SO2. In the strongly oxidative conditions of the pyrolysis tube some of the sulfur is converted to SO3 which does not react with the titrant. Accordingly,sulfur standards of n-butyl sulfide in isooctane or sulfur standards appropriate to sample boiling range and sulfur type and sulfur concentration should be prepared to guarantee adequate standardization. Recoveriesof sulfur as SO, lessthan 75 % are to be considered suspect. Low recoveries are an indication to the operator that he should check his parameters, his operating techniques, and his coulometricsystem.If the instrument is beingoperatedproperly, recoveriesbetween75 and 90 % are to be expected.Satisfactorystandard materials~ are given in Table 2. 10.6 If the fraction of sulfur converted to SO2 drops below 75 % of the standard solutions, prepare fresh standards. If a low-conversion factor persists, review procedural details. 10.7 With direct injection below 5 mg/kg sulfur the base line shift error due to the needle septum blank may become significant. Such error can be avoided by inserting the syringe needle into the hot inlet and allowing the needle septum blank to be titrated before injecting the sample. 11. Procedure 11.1 Flush the 10-p.L syringe several times with the unknown sample. Determine the sulfur concentration in accordance with Section 12. See Fig. 3 for examples of typical peaks. The samples were 0.32 mg/kg (0.31 in.2), 1.3 mg/kg (0.44 in.2), and 20.7 mg/kg (0.81 in.2). 11.2 Sulfur concentration may require adjustment of sensitivity settings or sample volume or both. 11.3 Peak-tailing may be controlled by decreasing the stirring rate or increasing the bias voltage or gain. Make any adjustments in bias voltage with the function switch in "stand-by" or "generator read" positions. 11.4 When an overshoot occurs, increase the stirring rate or decrease the bias voltage by 2-mV increments or decrease the gain until a satisfactory peak shape results. 11.5 Increasing the level of electrolyte in the titration cell will also help eliminate overshoot. 11.6 Any adjustments, such as "bias voltage," "gain," or "range-ohms," are allowable in order to obtain a satisfactory peak. 11.7 In some cases of very low-level sulfur samples, a

Typical Operational Conditions

Gas flow, cma/min Inert gas flow, cm3/mln Oxygen gas flow, cm3/min Fumace temperature, °C: Inlet zone Pyrolysis zone Outlet zone Titration cell

Satisfactory Standard Mstadals

200 40 160 750 900 900 stirrer speed set to produce slight vortex 160 low (approximately 200)

Approximate Range Settings Ohms 5 10 100 200 400 0.5 In./min chart drive 1-mV span with a sensitivity of 0.1 mV/In. 0.1 pL./s

6 Wallace, L. D., "Comparison of Oxidative and Reducfive Methods for the Microcoulometric Determinations of Sulfur in Hydrocarbons," Analytical Chemistry, Vol 42, March 1970, p. 393.

593

~ Bias 160mv Range 2001"/ Flow Rates O, - 100ml/min H e - 100ml/min Standard - 0.32 wt-ppm S Recovery - 68% Factor - 14.6118 nanogms/in' Injection - 20 p.I Peak Area - 0.31 in"

D 3961

Bias 160mv Range 400 Flow Rates O, - 160ml/min He- 40ml/min Standard - 1.3 wt-ppm S Recovery - 38% Factor - 13.0941 nanogms/in z Injection - 6.78 FI Peak Area - 0.44 in a

Bias 160mv Range 3 0 ~ Flow Rates O, - 160ml/min He - 40 ml/min Standard - 20.7 wt-ppm S Recovery- 54.4% Factor - 121.8678 nanagms/in' Injection - 6.8 #l Peak Area - 0.81 in z

4r

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Examples of Typical Peak and Areas at Three Sulfur Levels

12. Calculation 12.1 Calculate the sulfur content of the sample in milligrams per kilogram as follows:

negative peak may be observed. This may sometimes be corrected by injecting larger samples and increasing the oxygen content of the flow gases. 11.8 The titration cell may become erratic and desensitized occasionally. Rinse the electrodes with water and acetone. Blow dry with air or nitrogen. Then, very gently and with great care, slowly heat the electrodes over a flame to a dull orange color. Allow them to cool gradually before returning them to the cell. Allow the cell to stabilize before starting the analysis. 11.9 Low recoveries may result from inadequate conditioning of a new pyrolysis tube or having carbon in an old pyrolysis tube. In the ease of a new pyrolysis tube, continue to make conditioning runs until recovery reaches a maximum point and levels off. In the ease of an old pyrolysis tube, remove the tube from the furnace and allow it to cool. After cooling, rinse it with acetone to remove any hydrocarbon residue. Blow dry with air or nitrogen and wash with 1+1 hydrofluoric acid solution for 3 to 5 rain. Rinse with water followed by acetone and blow the tube dry. Return the tube to the furnace, bring it up to operating temperature and condition it with repeated injections of standards of suitable sulfur levels. 11.10 The exit tube may cause erratic performance, or varying or low recoveries, or a combination thereof. Remove and clean the tube by rinsing it with water, then acetone, and blow it dry. Repack it with quartz wool and replace it in the pyrolysis tube. I 1.11 Check a standard sample at least before every fourth sample.

Sulfur, mg/kg = /12.._..~B AI VD where: Am -- area under curve for the standard solution, in. 2 or mm 2. A 2 -- area under curve for sample, in. 2 or mm 2, B = total weight of sulfur in the injected standard, ng, V -- sample volume injected, FL, R = coulometer range switch setting, D -- density of sample, g/mL, V = volume of sample, I~L, and F -- recovery, ratio of mg/kg sulfur determined in standard divided by the known mg/kg sulfur in standard. This is not used in the calculations, but is used as an operational check. F-- 1.99AjB 103 R where: 1.99 -- coulometric replacement of triiodide ion consumed in titration cell as determined indirectly by Faraday's law. NOTE 10--The calculation equation is valid only when the chart speed is 0.5 in./min and a l-mV (span) recorder with a sensitivityof O.l mV/in, is used. NOTE 1I n I f a disk integrator is used, refer to the manufacturer's 594

(1~ D 3961 TABLE 3 Sample Cyclobexene,A Cyclollexane,B Styrene, A Styrene, B p-Xy#ene

Summary of Statistical Data

RepeetabilltyBetweenDays Within Laboratories Degreesof Range max. Average Freedom Sm 0.91 6.28 2.42 28.85 3.58

10 11 11 9 11

0.35 0.87 0.87 3.01 0.59

0.11 0.28 0.28 0.94 0.19

instructions for the appropriate equations.

TABLE 4 Sample

13. Report 13.1 Report the sulfur content of the sample as described in Section 12.

Cyciohaxene,A Cyciohexene,B Styrene, A Styrene, B p-Xylene

14. Precision 14.1 The following criteria should be used to judge the acceptability (95 % probability level) of results obtained by this method. The criteria were derived from a round robin between twelve laboratories. The data were run on two days by the same operator. 14.1.I Repeatability---Resultsin the same laboratory should not be considered suspect, unless they differby more than the amount shown in Table 3. 14.1.2 Reproducibility--Theresults obtained by each of two laboratories should not be considered suspect, unless

ReproducibilitySingle Result, Any Laboratory Degreesof Freedom 9 10 10 8 10

Sm+ b

Range max.

0.23 0.57 0.70 2.25 0.47

0.74 1.79 2.20 7.33 1,48

Summary of Statistical Calculations Average 0.91 6.28 2.42 28.85 3.58

Standard Coefficientof Deviation Variation 0.214 0.530 0.668 2.147 0.449

23.57 8.44 27.56 7.44 12.56

DF 9 10 10 8 10

they differ by more than the amount shown in Table 3. 14.1.3 For a summary of statistical calculations, see Table 4. 15. Keywords 15.1 aromatic hydrocarbons; benzene; cyclohexane; isooctane; microcoulometry; p-xylene; styrene; sulfur

The American Society for Testing end Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years end ff not revised, either reepproved or withdrawn. Yourcomments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful conalderaticn at a meeting of the responsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103.

595

( ~ l ~ Designation: D 4006-81 (Reapproved 1995)~1

An American National Standard

Designation: Manual of Petroleum Measurement Standards, Chapter 10.2 (MPMS)

I)11 I ~ H H I I I , . I'1 . . . l u ~

Designation: IP 358/90

Standard Test Method for Water in Crude Oil by Distillation ~ This standard is issued under the fixed designation D 4006; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (~) indicates an editorial change since the last revision or reapproval.

Thts test method has been approved by the sponsoring committees and accepted by the Cooperating Societies in accordance with established procedures. This method was tssued as a joint ASTM-API-IP standard in 1981. ~l NOTE--Editorial changes made throughout in September 1995.

3. Summary of Test Method 3.1 The sample is heated under reflux conditions with a water immiscible solvent which co-distills with the water in the sample. Condensed solvent and water are continuously separated in a trapmthe water settles in the graduated section of the trap, and the solvent returns to the distillation flask.

1. Scope 1.1 This test method covers the determination of water in crude oil by distillation. 1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific precautionary statements, see 6.1 and 7.

4. Significance and Use 4.1 A knowledge of the water content of crude oil is important in the refining, purchase, sale, or transfer of crude oils.

2. Referenced Documents 2.1 A S T M Standards: D 95 Test Method for Water in Petroleum Products and Bituminous Materials by Distillation 2 D 96 Test Methods for Water and Sediment in Crude Oil by Centrifuge Method (Field Procedure) 2 D473 Test Method for Sediment in Crude Oils and Fuel Oils by the Extraction Method2 D 665 Test Method for Rust-Preventing Characteristics of Inhibited Mineral Oil in the Presence of Water2 D 1796 Test Method for Water and Sediment in Fuel Oils by the Centrifuge Method (Laboratory Procedure)2 D 4057 Practice for Manual Sampling of Petroleum and Petroleum Products3 D 4177 Practice for Automatic Sampling of Petroleum and Petroleum Products3 E 123 Specification for Apparatus for Determination of Water by Distillation4 2.2 API Standards: MPMS 8 "Sampling Petroleum and Petroleum Products ''5 ' This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D 02.02 on Static Petroleum Measurement. Current edition approved March 27, 1981. Published May 1981. 2 Annual Book of ASTM Standards, Vol 05.01. Annual Book of ASTM Standards, Vol 05.02. 4 Anmtal Book of ASTM Standards, Vol 14.02. SAvailable from the American Petroleum Institute, 1220 L St., N.W., Washington, DC 20005.

5. Apparatus 5.1 The preferred apparatus, shown in Fig. 1, consists of a glass distillation flask, a condenser, a graduated glass trap, 6 and a heater. Other types of distillation apparatus are specified in Specification E 123. Any of these apparatus will be acceptable for this method provided it can be demonstrated that they operate within the precision established with the preferred apparatus. 5.1.1 Distillation Flask--A 1000-mL round-bottom, glass, distillation flask fitted with a 24/40 female taper joint shall be used. This flask receives a 5-mL Specification E 123 Type E calibrated, graduated water trap with 0.05-mL graduations. The trap will be fitted with a 400-mL Liebig condenser. A drying tube filled with desiccant (to prevent entrance of atmospheric moisture) is placed on top of the condenser. 5.1.2 Heater--Any suitable gas or electric heater that can uniformly distribute heat to the entire lower half of the flask may be used. An electric heating mantle is preferred for safety reasons. 5.1.3 The apparatus used in this test will be accepted when satisfactory results are obtained by the calibration technique described in Section 9. 6 Available on special order from Scientific Glass Apparatus Co., Bloomfield, N.J. 07003.

596

(~) D 4006 handling procedure shall apply in addition to those covered in 7.l.1. 7.1.2.1 The sample size shall be selected as indicated below based on the expected water content of the sample:

FIG. 1

Distillation Apparatus

6. Solvent 6.1 Xylene (Warning--see Note 1), reagent grade. A solvent blank will be established by placing 400 mL of solvent in the distillation apparatus and testing as outlined in Section 10. The blank will be determined to the nearest 0.025 mL and used to correct the volume of water in the trap as in Section 11.

Approximate Sample Size, g or mL

50.1-100.0 25.1- 50.0 10.1- 25.0 5.1- 10.0 1.1- 5.0 0.5- 1.0 less than 0.5

5 10 20 50 100 200 200

If there is any doubt about the uniformity of the mixed sample, determinations should be made on at least three test portions and the average result reported as the water content. 7.1.2.2 To determine water on a volume basis, measure mobile liquids in a 5, 10, 20, 50, 100, or 200-mL calibrated, graduated cylinder (NBS Class A) depending on the sample size indicated in 7.1.2.1. Take care to pour the sample slowly into the graduated cylinder to avoid entrapment of air and to adjust the level as closely as possible to the appropriate graduation. Carefully pour the contents of the cylinder into the distillation flask and rinse the cylinder with at least 200 mL of xylene in five steps of 40 mL and add the rinsings to the flask. Drain the cylinder thoroughly to ensure complete sample transfer. 7.1.2.3 To determine water on a mass basis, weigh a test portion of sample in accordance with 7.1.2.1, pouring the sample directly into the distillation flask. If a transfer vessel (beaker or cylinder) must be used, rinse it with at least five portions of xylene and add the rinsings to the flask.

8. Calibration 8.1 Calibrate both the trap and the entire assembly prior to use as indicated in 8.1.1 through 8.1.3. 8.1.1 Verify the accuracy of the graduation marks on the trap by adding 0.05-mL increments of distilled water, at 20"C, from a 5-mL microburet or a precision micro-pipet readable to the nearest 0.01 mU If there is a deviation of more than 0.050 mL between the water added and water observed, reject the trap or recalibrate. 8.1.2 Also calibrate the entire apparatus. Put 400 mL of dry (0.02 % water maximum) xylene in the apparatus and test in accordance with Section 9. When complete, discard the contents of the trap and add 1.00 --- 0.01 mL of distilled water from the buret or micro-pipet, at 20"C, directly to the distillation flask and test in accordance with Section 9. Repeat 8.1.2 and add 4.50 __. 0.01 mL directly to the flask.The assembly of the apparatus is satisfactory only if trap readings are within the tolerances specified here:

NOTE l - - W a r n i n g - - E x t r e m e l y Flammable. Vapor harmful.

6.2 The xylene used in this procedure is generally a mixture of ortho, meta, and para isomers and may contain some ethyl benzene. The typical characteristics for this reagent are: Color (APHA) Boiling range Residue after evaporation Sulfur compounds (as S) Substances darkened by H2SO4 Water (H20) Heavy metals (as Pb) Copper (Cu) Iron (Fe) Nickel (Ni) Silver (Ag)

Expected Water Content, weight or volume %

not more than 10 137-144°C 0.002 % 0.003 % Color pass test 0.02 % 0.1 ppm O, 1 ppm 0.1 ppm 0.1 ppm 0.1 ppm

7. Sampling, Test Samples, and Test Units 7.1 Sampling is defined as all steps required to obtain an aliquot of the contents of any pipe, tank, or other system and to place the sample into the laboratory test container. 7.1.1 Laboratory Sample--Only representative samples obtained as specified in Practice D 4057 and Method D 4177 shall be used for this method. 7.1.2 Preparationof Test Samples--The following sample

Limits Capacity of Trap at 20"C, mL

Volume of Water Added at 20"C, mL

Permissible for Recovered Water at 20"C, mL

5.00 5.00

1.00 4.50

1.00 _+ 0.025 4.50 + 0.025

8.1.3 A reading outside the limits suggests malfunctioning due to vapor leaks, too rapid boiling, inaccuracies in graduations of the trap, or ingress of extraneous moisture. 597

~') PICK

D 4006 JET SPRAY TUBE

SCRAPER

I 3/16" OD

1 h

i~

IHHJtHINII~'2"~'J ~

I I

D,A

V

5ti6" l I / / / i / / / fJJ

I

I

•

'-f-- 1/2"

3/4"

-1

[.q--1/ 4 ".-~-[-,--1/ 4" ,,~

TIP

I I I I I

8- 028" DIA ~ AT 45 ° TO EACH OTHER ON 2-1/4" APART CIRCLES

I i / /

SECTION "A-A"

'1'

SCALE: 2X

DRILL & TAP FOR 1/8" ROD-3/16" DP THD-1/2" D p {

I 1/4" OR 3/16" STAINLESS STEEL TUBE WITH PLUGGED END

DETAIL OF TIP SCALE. 2X MATERIAL. TEFLON

I

=,

1/8" DIAMETER STAINLESS STEEL ROD

P'T I

I

I

I

15"

II II II II

1/16"BRASS OR 9RONZE ROD 4 HOLES AT 90 °

3/16-i

,70 DR,LL Co 2 8 " ) ~ 4 HOLESAT9 0 " ~

1_

I I I

I

I

I

b~ 1

L

1/,

SEE DETAIL ABOVE

S/16"TAPER

FIG. 2

1

/16"

1/4"

PRESS F END PLUG

Pick, Scraper, and Jet Spray Tube for Distillation Apparatus

reduce bumping. Glass beads or other boiling aids, although less effective, have been found to be useful. 9.3 Assemble the apparatus as shown in Fig. l, making sure all connections are vapor and liquid-tight. It is recommended that glass joints not be greased. Insert a drying tube containing an indicating desiccant into the end of the condenser to prevent condensation of atmospheric moisture inside the condenser. Circulate water, between 20 and 250C, through the condenser jacket. 9.4 Apply heat to the flask. The type of crude oil being evaluated can significantly alter the boiling characteristics of the crude-solvent mixture. Heat should be applied slowly during the initial stages of the distillation (approximately 1/2 to l h) to prevent bumping and possible loss of water from the system. [Condensate shall not proceed higher than three quarters of the distance up the condenser inner tube (Point A in Fig. l). To facilitate condenser wash down, the condensate should be held as close as possible to the condenser outlet.] After the initial heating, adjust the rate of boiling so that the

These malfunctions must be eliminated before repeating 8.1.2. 9. Procedure 9.1 The precision of this method can be affected by water droplets adhering to surfaces in the apparatus and therefore not settling into the water trap to be measured. To minimize the problem, all apparatus must be chemically cleaned at least daily to remove surface films and debris which hinder free drainage of water in the test apparatus. More frequent cleaning is recommended if the nature of the samples being run causes persistent contamination. 9.2 To determine water on a volume basis, proceed as indicated in 7.1.2.2. Add sufficient xylene to the flask to make the total xylene volume 400 mL. 9.2.1 To determine water on a mass basis, proceed as indicated in 7.1.2.3. Add sufficient xylene to the flask to make the total xylene volume 400 mL. 9.2.2 A magnetic stirrer is the most effective device to 598

~ 125 <> 100 I-uJ z 075 z 0

O 4006

1

I

I

~ C l B I L I T Y -

-

!

ATABILITY

~: .050 t,09 < .O25 I

I

I

025 .050 075 .100 AVERAGEWATER,PERCENT,BY DISTILLATION FIG. 3

Basic Sediment and Water Precision

condensate proceeds no more than three quarters of the distance up the condenser inner tube. Distillate should discharge into the trap at the rate of approximately 2 to 5 drops per second. Continue distillation until no water is visible in any part of the apparatus, except in the trap, and the volume of water in the trap remains constant for at least 5 min. If there is a persistent accumulation of water droplets in the condenser inner tube, flush with xylene. (A jet spray washing tube, see Fig. 2, or equivalent device is recommended.) The addition of an oil-soluble emulsion breaker at a concentration of 1000 ppm to the xylene wash helps dislodge the clinging water drops. After flushing, redistill for at least 5 min (the heat must be shut off at least 15 min prior to wash-down to prevent bumping.) After wash-down, apply heat slowly to prevent bumping. Repeat this procedure until no water is visible in the condenser and the volume of water in the trap remains constant for at least 5 min. If this procedure does not dislodge the water, use the TFE-fluorocarbon scraper, pick (Fig. 2), or equivalent device to cause the water to run into the trap. 9.5 When the carry-over of water is complete, allow the trap and contents to cool to 20°C. Dislodge any drops of water adhering to the sides of the trap with the TFEfluorocarbon scraper or pick and transfer them to the water layer. Read the volume of the water in the trap. The trap is graduated in 0.05-mL increments, but the volume is estimated to the nearest 0.025 mL.

A = m L of water in trap, B = mL of solvent blank, C = m L of test sample, M = g of test sample, and D = density of sample, g / m E Volatile water-soluble material, if present, may be measured as water. 11. Report 11.1 Report the result as the water content to the nearest 0.025 % and reference this Test Method D 4006 as the procedure used.

12. Precision and Bias 12.1 The precision of this test method, as obtained by statistical examination of interlaboratory test results in the range from 0.01 to 1.0 %, is described in 12.1.1 and 12.1.3. 12.1. l Repeatability--The difference between successive test results, obtained by the same operator with the same apparatus under constant operating conditions on identical test material, would, in the long run, in the normal and correct operation of the test method, exceed the following value in only one case in twenty: From 0.0 % to 0.1% water, see Fig. 3. Greater than 0.1% water, repeatability is constant at 0.08. 12.1.2 Reproducibility--The difference between the two single and independent test results obtained by different operators working in different laboratories on identical test material, would, in the long run, in the normal and correct operation of the test method, exceed the following value in only one case in twenty: From 0.0 % to 0.1% water, see Fig. 3 Greater than 0.1% water, reproducibility is constant at 0. I 1.

10. Calculation 10.1 Calculate the water in the sample as follows: Volume % = (A - B._._~x) 100 C Volume % = (A - B____~.x) 100

(M/D)

) R ( A-

13. Keywords 13.1 apparatus; calibration; crude oil; distillation; procedure; sampling; solvent; water

Mass % = -_.___z, x 100 M where:

599

~

D 4006

ANNEX

(Mandatory Information) A1. PRECAUTIONARY S T A T E M E N T Use with adequate ventilation. Avoid breathing of vapor or spray mist. Avoid prolonged or repeated contact with skin.

AI.1 Xylene--Precaution Keep away from heat, sparks, and open flame. Keep container closed.

APPENDIX

(NonmandatoryInformation) X.1 PRECISION AND BIAS OF M E T H O D S FOR D E T E R M I N I N G WATER IN CRUDE OILS tion. The entire concentration range studied was from zero to 1.1% water. These expected values were used to determine the accuracy of the test procedures. X 1.3.2 Sample Preparation: XI.3.2.1 The crude oils were received from the suppliers in barrels. After mixing by rolling and turning, two 5-gal samples and one 250-mL sample were taken from each barrel. The Minas crude had to be heated to 66"C (150°F) with a barrel heater before samples could be drawn. The 250-mL samples of each crude, as received, were used to establish the base case in water content. Each sample was analyzed by Test Method D 95 to determine the water content. These starting points are shown in Table X I. 1. XI.3.2.2 To obtain "water-free" samples of crude oil, one 5-gal sample of each of two crudes was distilled over the temperature range of initial to 300*F vapor temperature. This distillation was done using a 15 theoretical plate column at 1:1 reflux ratio. XI.3.2.3 "Spiking" samples to a known water concentration was done using synthetic sea water (as described in Test Method D 665. The mixing and homogenization was done with a static blender. The complete listing of samples with their expected water contents is shown in Table X I.2. X 1.3.2.4 The samples for each cooperator were bottled so that the entire sample had to be used for a given test. In this way, any effect due to settling or stratification of water was eliminated. XI.3.2.5 Samples were coded to mask the presence of duplicates and a table of random numbers dictated the running order of tests. XI.3.2.6 The participating laboratories were:

XI.1 Summary X 1.1.1 This round-robin testing program has shown that the distillation method as practiced is somewhat more accurate than the centrifuge method. The average correction for the distillation method is about 0.06, whereas the centrifuge correction is about 0.10. However, this correction is not constant nor does it correlate well with the measured concentration. X 1.1.2 There is a slight improvement in the precision of the distillation method over the present Test Method D 95: 0.08 versus 0.1 for repeatability and 0.11 versus 0.2 for reproducibility. These figures are applicable from 0.1 to 1% water content; the maximum level studied in this program. X I.1.3 The precision of the centrifuge method is worse than the distillation: repeatability is about 0.12 and the reproducibility is 0.28. XI.2 Introduction X 1.2.1 In view of the economic importance of measuring the water content of crude oils precisely and accurately, a working group of API/ASTM Joint Committee on Static Petroleum Measurement (COSM) undertook the evaluation of two methods for determining water in crudes. A distillation method (Test Method D 95), and a centrifuge method (Test Method D 1796) were evaluated in this program. Both methods were modified slightly in an attempt to improve the precision and accuracy. XI.3 Experimental X I.3.1 Samples--The following seven crude oils were obtained for this program: Crude San Ardo Arabian Light Alaskan Arabian Heavy Minas Fosterton Nigerian

Source Texaco Mobil Williams Pipe Line Exxon Texaco Koch Industries Gulf

TABLE X1.1

Base Case--Water Content of Crudes

Crude Oil

• H20

San Ardo Arabian Light Alaskan

0.90 0.15 0.25 0.10 0.50 0.30 <0.05

Arabian Heavy Minas

By removing all water or adding known amounts of water to the above crudes, 21 samples were prepared for testing. Each crude oil was represented at three levels of water concentra-

Fosterton Nigerian

600

~ Water Content of Crude Oil Samples

TABLE X l . 2

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

Found .

.

.

.

.

.

.

.

.

.

.

.

.

.

Added .

.

.

San Ardo

0.90

Arabian Light

0.15

Alaskan

0.25

Arabian Heavy

0.10

Minas

0.50

Fosterton

0.30

Nigerian

0.05

.

.

.

.

.

.

.

.

.

.

.

.

.

Expected

Distillation

Centrifuge

0.90 0.0 0.40 0.15 0.25 1.05 0.25 0.45 1.05 0.10 0.0 0.10 0.50 0.60 1.00 0.30 0.50 1.10 0.05 0.45 0.85

0.90 0.04 0.42 0.10 0.2t 0.86 0.21 0.39 0.92 0.11 0.06 0.18 0.45 0.53 0.96 0.18 0.33 0.86 0.02 0.35 0.65

0.79 0.05 0.021 0.12 0.13 0.78 0.14 0.32 0.98 0.04 0.02 0.10 0.34 0.47 0.97 0.07 0.20 0.77 0.01 0.32 0.65

Expect .

.

.

.

.

.

.

.

.

0 dried dried + 0.4 0 0.10 0.90 0 0.20 O.8O 0 dried dried + 0.1 0 0.10 0.50 0 0.20 0.80 0 0.40 0.80

Determination of Water in Crude Oils, % H=O

TABLE X l . 3

% H20

Crude Source .

D 4006

0.90 0.0 0.40 0.15 0.25 1.05 0.25 0.45 1.O5 0.10 0.0 0.10 0.50 O.6O 1.00 0.30 0.50 1.10 <0.05 0.45 0.85

TABLE Xl.4

Chevron Research Co. Exxon Research and Engineering Co. Mobil Research and Development Corp. Texaco, Inc. Shell Charles Martin, Inc. Gulf Research and Development Co. XI.3.3 Test Modifications--The base methods studied were modified slightly in an effort to improve the performance. The modifications were as follows: XI.3.3.1 Test Method D 95mSample size was standardized at 200 g and the solvent volume was increased to maintain the original solvent/sample ratio. XI.3.3.2 Test Method D 1796~A heated centrifuge (held near 60"C (140*F)) and use of a demulsifier were mandatory. Eight-inch centrifuge tubes were also specified. Toluene saturated with water at 140*F was the only permissible solvent. The suggested demulsifier was a Tret-O-Lite material, F65. 7

Corrections to be Applied to Measured Values to Obtain "True" Water Content

Method

Laboratory

D 1796 Centrifuge

C E M T S I G Avg C E M T S I G Average

D 95 Distillation

Correction +0.152 ± +0.029 + +0.196 + +0.196 ± +0.160 + +0.116 ± +0.121 ± +0.132 +0.777 ± +0.048 ± +0.082 ± +0.064 ± +0,077 ± +0.061 ± +0.072 ± +0.069

0.095 0.125 0.135 0.100 0.122 0.126 0.115 0.082 0.078 0.077 0.079 0.107 0.112 0.096

method as a combination of Test Methods D 95 and D 473, it was decided that data obtained by Test Method D 95 in one laboratory would be the "true value." Table X I.3 shows the expected value compared to each sample average using this criterion. It can be seen that both methods are biased low. However, the distillation test method (Test Method D 95) appears less biased than the centrifuge. Since the bias

X1.4 Results and Discussion

X 1.4.1 Accuracy: X 1.4.1.1 Accuracy or bias is defined as the closeness of the measured value to the "true value." Since there is no independent absolute method available to determine this true value for these samples, some other means must be used. Two options were considered: (1) Select one laboratory and one method as the "reference system" and define these results as the true value, or (2) Spike samples with known amounts of water. The measured difference between the original and unspiked samples can be compared to the known added water to determine the bias (accuracy). Both approaches were investigated in this study. XI.4.1.2 Since Test Methods D 96 defines the base

TABLE Xl.5

Bias of Methods Estimated from Spiked Samples

Water Added,A % 0.10 0.10 0.10 0.20 0.20 0.40 0.40 0.50 0.80 0.80 0.80 0.90

7 Tret-O-Lite is a registered trademark of Tretolite Div., Petrolite Corp., 369 Marshall Ave., St. Louis, MO. Even though Tret-O-Lite F65 was used during the round robin, there are many demulsifiers on the market that may be useful.

D 95 A

Found

A

0.10 0.08 0.10

0 -0.02 0 -0.04 -0.05 -0.01 -0.07 -0.01 -0.10 -0.10 -0.16 -0.14 -0.06

0.05 0.00 0.10 0.16 0.12 0.16 0.30 0.52 0.73 0.70 0.63 0.69

-0.05 -0.10 0 -0.04 0.00 -0.24 -0.10 +0.02 -0.07 -0.10 -0.17 -0.21 -0.10

0.16 0.15 0.39 0.33 0.49 0.70 0.70 0.64 0.76 Average

D 1796

Found

A Equal water additionsshown are to different crude oils.

601

1@) D 4006 TABLE X l , 6

Round-Robin Results of Water in Crude Oils by ASTM D 95 and ASTM D 1796 Distillation Test Method ASTM D 95

Laboratories

Samples 1

9

15

6

18

1

0.86 0.86

0.90 0.92

0 . 9 1 0 . 9 1 0.88 0.92 0.86 0.85

2

0.90 0.91

0,94 0.94

0.99 1.00

0.90 0.92

3

0.80 0.85

0.94 0.94

0.98 0.98

4

0.93 0.93

6

2

11

19

3

8

13

14

17

20

21

4

0.00 0.02 0 . 0 1 0,02

0.00 0.02

0,40 0.39

0.39 0.40

0.46 0,46

0.75 0.53

0.25 0.38

0,35 0,33

0.67 0.66

0.10 0.09

10

12

16

0.15 0.20 0.16 0 . 2 1 0 . 2 1 0.20

5

0.13 0.13

0.18 0.15

0.90 0.90

0.05 0.06

0,34 0.06

0,04 0.04

0.43 0,48

0.40 0.40

0.48 0.47

0.53 0.58

0.39 0,36

0.35 0.30

0.70 0.69

0.09 0.25 0 . 1 1 0.24

0.25 0.25

0.18 0.19

0 . 1 1 0.20 0.14 0.20

0.85 0.83

0.90 0.90

0.05 0.02

0.00 0.03

0.00 0.00

0.35 0.54

0.38 0.40

0.45 0.43

0,43 0.55

0.35 0.33

0.33 0.33

0.65 0.65

0.07 0.10

0.20 0,15

0.23 0.23

0.18 0.15

0.05 0.07

0.92 0.90

0.89 0.90 0 . 9 1 0.89

0.88 0,90

0.07 0.07

0,02 0.02

0.00 0.04

0,42 0.42

0,40 0,39

0.42 0.43

0.52 0,52

0,35 0.33

0,35 0.35

0.66 0.67

0.10 0.10

0.19 0.20

0.23 0.19

0.18 0.16

0.10 0.20 0 . 1 1 0.19

0.87 0.86

0.88 0.92

0.87 0.83

0.86 0.80

0.86 0.80

0.07 0.07

0.07 0.09

0.05 0.04

0.39 0.39

0 . 4 1 0.42 0.40 0.37

0 , 5 1 0.23 0.47 0.35

0.39 0.35

0.65 0.60

0 , 1 1 0.2t 0.12 0.20

0 . 2 1 0 . 2 1 0.16 0,24 0.24 0.18

0.20 0.16

6

0,98 1.01

0,94 0.94

0.85 1.37

0.79 0.84

0.74 0.89

0.04 0.02 0 . 0 1 0.00

0.00 0.58 0 . 0 1 0.48

0.39 0.80

0.45 0.66

0.44 0.56

0.36 0.30

0.38 039

0.61 0,66

0 . 1 1 0.24 0.13 0.25

0.23 0.24

0.20 0.07 0 . 2 1 0.05

0.24 0.18

7

0.91 0.97

0.88 0.92

0.97 1,03

0.85 0.84

0.80 0.80

0.05 0.02

0 . 0 1 0 . 0 1 0.42 0.13 0 . 0 1 0.39

0.40 0.35

0 , 4 1 0.53 0.45 0.47

0.34 0.35

0.36 0.38

0.64 0.65

0.05 0.15

0.18 0.23

0.15 0.15

21

4

0.18 0.20

7

0.15 0.16

0.18 0.18 0 . 1 1 0.15

Centrifuge Test Method D 1796

Labora-

Samples

tories

1

9

15

1

0,82 0.79

0.90 0.89

0.87 0.88

2

1.03 0,88

3

6

18

2

11

19

3

8

0.80 0.70 0 . 8 1 0.74

0.05 0.05

0.02 0.02

0.00 0.02

0.23 0.23

1.09 1.06 1 . 1 1 1.12

0.74 0.74

0,95 1.00

0.19 0.06

0.07 0.05

0.00 0.00

0.19 0.40 0 . 3 1 0.43

0.65 0.60

0.80 0.85

0.90 0,90

0.70 0.60

0.70 0.70

0.07 0.07

0,00 0.00

0.00 0.02

0.10 0,10

4

0.73 0,79

0.95 1.00

0.88 0.90

0.85 0.75

0.80 0.70

0.00 0.00

0.00 0.00

0.00 0,00

5

0.69 0,76

1.55 1.10

0 . 5 1 0.87 0.87 0.93

0.83 0 . 0 1 0.03 0 . 4 1 0 . 0 1 0.05

6

0.72 0,86

0.75 0.90

1,59 1.44

0.85 0,65

0.65 0.65

0.07 0.09

7

0.88 0.90

1.00 0.85

0.85 0.80

0.85 0.80

0.70 0.80

0.00 0.00

13

5

7

10

12

16

0.07 0.06

0.05 0.06

0.03 0.03

0.02 0.02

0.02 0.04

0.61 0.85

0.15 0.20 0 . 2 1 0.37

0.20 0.42

0.20 0.17

0.06 0.06

0.20 0.04

0.20 0,20

0.60 0,45

0.02 0.02

0.02 0.02

0.07 0,12

0,02 0.02

0.00 0.00

0,02 0.02

0.30 0.27

0.63 0.55

0.00 0.00

0,10 0.05

0.10 0.13

0.05 0.05

0.00 0.00

0.05 0.05

0.30 0.07

0 , 2 1 0.39 0.72 0.19 0 . 0 1 0.69

0.75 0.06

0.13 0 . 0 1 0 . 2 1 0.03 0 . 1 1 0.02 0.09 0.03

0.05 0.12

0.25 0.38

0.52 0.52

0.20 0.25

0.45 0.38

0.75 0.80

0.05 0.10

0.15 0.10

0.05 0.13

0.05 0.10

0.05 0.05

0,05 0.10

0.30 0.30

0.40 0,35

0.25 0.13

0.23 0.25

0.63 0.60

0.10 0.18

0.18 0.20

0.25 0.30

0.20 0.15

0.00 0.00

0,18 0.10

0.25 0.38 0 . 3 1 0.35

14

17

20

0.48 0.19 0 . 4 1 0.17

0.27 0.29

0.65 0.02 0 . 6 1 0.02

0.50 0.58

0.58 0.60

0.38 0.34

0.45 0.50

0.30 0.34

0.30 0.40

0.42 0.50

0.06 0,10

0.18 0.16

0.27 0.27

0.33 0.40

0.46 0.45

0.15 0.15

0.03 0.02

0.18 0.30

0 . 2 1 0,16 0.54 0.20

0.05 0.05

0.05 0.05

0.35 0.32

0,33 0.25

0.00 0.00

0.05 0.05

0.15 0.10

0.20 0.35

XI.4.2 Precision: XI.4.2.1 To estimate the precision of the tests, the data were analyzed following the ASTM guidelines pub!ished as Research Report RR D-2 I007, "Manual on Determining Precision Data for ASTM Methods on Petroleum Products" (1973). XI.4.2.2 Seven laboratories participated in the round robin. Basic sediment and water was measured on 21 crude oil samples in duplicate by the distillation method (Test Method D 95) and the centrifuge test method (Test Method D 1796). The raw data are presented in Table X1.6. XI.4.3 Test for Outliers--Procedures for rejecting outliers recommended in ASTM RRD-2 1007, "Manual on Determining Precision Data for ASTM Methods on Petroleum Products and Lubricants" were followed. X1.4.3.1 Distillation Method--The following table lists the outliers rejected and the substituted values:

is not the same in every laboratory (Table X1.4), it is not possible to recommend inclusion of a correction factor in the methods. This data treatment suggests that the centrifuge method, on the average, yields results about 0.06 % lower than the distillation. The respective biases are -0.13 for the centrifuge and -0.07 for the distillation method. X1.4.1.3 A more reliable estimate of bias may be obtained if consideration is given only to those samples to which water was added. In this case, the measured differences between the unspiked sample and the spiked sample compared to the actual water added would be indicative of the bias. Table X I.5 shows these differences for each method. On this basis the centrifuge bias has improved slightly, while the distillation is about the same. The difference between the two methods is now 0.04 rather than 0.06. It should be noted that bias is greatest with both methods at higher water contents.

602

~'~ D 4006 I

I

I

I

I

I

0.11 1

010 ,~ 0 , 0 9 ~0.08 I--

z

Z 007O

-~ 0060

uJ n,- 0 , 0 5 o..

¢,o ,<

w

004 I

0.03 0.02 0.01

1, 0 01

FIG. X1.1

I

I

I

I

I

I

I

0.02 0 03 0.04 0.05 0 06 0.07 AVERAGE WATER, PERCENT, BY DISTILLATION

0.08

085

Basic Sediment Water Precision for ASTM Test Method D 95 Distillation Method (Based on Seven Laboratories)

Laboratory

Sample

Rejected Value

Substituted Value

Laboratory

Sample

Rejected Value

Substituted Value

1 3 2 6 6

14 3 I1 13 15

0.75 0.35, 0.54 0.34 0.66 1,37

0.53 0.445 0.06 0.45 0.85

2 2 2 6 6

2 7 21 6 15

0.19 0.42 0.85 0.65 1.59, 1.44

0.05 0.20 0.6 I 0.85 0.922

XI.4.3.2 Centrifuge Method." (a) The data from Laboratory 5 were rejected outright because incorrect-size centrifuge tubes were used (letter, Shell Oil to E. N. Davis, cc: Tom Hewitt, February 9, 1979). Statistical tests showed that Laboratory 5's data did not belong to the same population as the other data. (b) Laboratory 2's data were also suspect and did not appear to belong to the same population as the other data. However, it was learned that Laboratory 2's results were closest to actual levels of water added to the samples. There is, therefore, a dilemma on whether or not to reject Laboratory 2's data. As a compromise, precision was calculated with and without Laboratory 2's results. The following table lists the outliers rejected and the substituted values when Laboratory 2's results are retained:

0 20

I

I

I

With Laboratory 2's results omitted, only Laboratory 6's results listed above were rejected. X 1.4.4 Calculation of Repeatability and Reproducibility." XI.4.4.1 Repeatability and reproducibility were obtained by fitting curves o f the appropriate precision o f the results on each sample versus the mean value o f each sample. An equation of the form: S

A X ( I - e "b~)

|

I

I

~

I

~

I

REPRODUCIBILITY

REPEATABILITY

I

I

I

I

I

I

I

I

I

0.02

0.04

0.06

0 08

0.10

0 12

0.14

0.16

0.18

AVERAGE WATER, PERCENT, BY CENTRIFUGE

FIG. X1.2

(1)

where: S = precision, 2 = sample mean, and A and b are constants. was found to best fit the data. The values o f the constants A and b were calculated by regression analysis of the linear logarithmic equation: log S = log A/log (I - et'~).

~015 _z z O ~0.I0 ttl er a. 0 0 5 io9 < 0

=

Basic Sediment and Water Precision for ASTM Test Method D 1796 Centrifuge Method (Based on Five Laboratodes)

603

~)

O 4006 TABLE X1.7 ASTM Precision Intervals: ASTM D 95 (7) %Water Repeatability Reproducibility ~ Water 0.000 0.000 0.000 0.000 0.005 0.017 0.023 0.005 0.010 0.030 0.041 0.010

X 1.4.4.2 The standard deviation for repeatability for each sample was calculated from pair-wise (repeat pairs) variances pooled across the laboratories. The standard deviation for reproducibility was calculated from the variance of the mean values of each pair. This variance is equal to the sum of two

variances, the variance aL 2 due to differences between laboratories and the variance due to repeatability error o'i. 2 divided by the number of replicates

Using the data calculated above for each sample, the following values for the constants in Eq 1 were obtained: Distillation Method

7 Laboratories

Reproducibility

47.41 0.2883

47.41 0.0380

Constant b A

Centrifuge Method

6 Laboratories

Repeatability Constant b A

Reproducibility

11.23

11.23

0.0441

0.041 0.049 0.056

0.055 0.066 0.075

o.03o

0.061

o.062 0.087

0.035

0.040 0,045 0.050 0.055 0.060 0.065 0.070 0.075 0.080 0,085 0,090 0.095 0,100 0.105 0.110 0.115 0.120 0.125 0,130

0.068 0.071 0.073 0.074 0.075 0.076 0.077 0.076 0.078 0.079 0.079 0.079 0.079 0.079 0.080 0.080 0.080 0.080 0.080

0.091 0.095 0.097 0.100 0.101 0.103 0.104 0.104 0.105 0.106 0.106 0.106 0,107 0.107 0.107 0.107 0.107 0.107 0,107

0.040 0.045 0.050 0.055 0.060 0.065 0,070 0,075 0,080 0.085 0.090 0.095 0.100 0.105 O,110 0,115 0,120 0.125 0,130

0.035

ar 2 ~- Gr2/rl + GL 2 ( n = 2)

Repeatability

0.015 0.020 0.025

0,1043

0.065

0.015 0.020 0.025

0.o3o

5 Laboratories Repeatability

Reproducibility

17.87 0.0437

17.87 0.0658

Constant b A

repeatabilities and reproducibilities are: Repeatability

The values of precision calculated by Eq 1 were multiplied by 2.828 (2 x J2) to convert them to the ASTM-defined repeatability and reproducibility, XI.4.4.3 The curves of repeatability and reproducibility for the distillation method in the range 0 to 0.09 % water are shown in Fig. XI.I. These data are also tabulated in the Table XI.7. The curves for the centrifuge method in the range 0 to 0.2 % water are shown in Fig. X I.2 (fivelaboratory case) and Fig. X 1.3 (six-laboratory case). XI.4.4.4 For higher levels of water the limiting

0,30

1

I

I

Method

Range of Concentration, %

Value, %

Distillation Centrifuge (five-laboratory case) Centrifuge (six-laboratory case)

>0.085 >0.155 z0.235

o.12

0.08

o. J2

Reproducibility Range of Value,% Concentration, %

Method

o.105 o.19 0.29 XI.4.4.5 It should be pointed out that at the lowest water levels, the precision "statements" for some of the analyses do Distillation Centrifuge (five-laboratory c~..s¢) Centrifuge (six-laboratory case)

I

I

l

I

:,'0.085 ~0.325 >0.315

I

I

I 0.16

I/ 0.18

> rr 0.20 LU I-z z _Oo15 O LLI n~

REPEATABILITY

0 05

0

I 002

I 004

I 0.06

I 0.08

I 0 10

I 0.12

I, 0.14

AVERAGE WATER, PERCENT, BY CENTRIFUGE

FIG. Xl.3

Basic Sediment and Water Precision for ASTM Test Method D 1796 Centrifuge Method (Based on Six Laboratodes)

604

~'~ D 4006 examined. The conclusions are: X I.5.1.1 Distillation Method: (a) Precision is related to water content up to about 0.08 % water. (b) In the range from 0.01 to 0.08, repeatability varies from 0.020 to 0.078 and reproducibility from 0.041 to 0.105. (c) Above 0.1% water, the repeatability is 0.08 and the reproducibility is 0.11. X 1.5.1.2 Centrifuge Method." (a) Repeatability is related to water content up to about 0.2 % water and reproducibility up to about 0.3 %. (b) In the range 0.01 to 0.2, repeatability varies from 0.01 to 0.11 and reproducibility in the range 0.02 to 0.3 from 0.03 to 0.28. XI.5.2 It is recommended that: XI.5.2.1 Precision should be presented as a graph in the range where precision varies with water content. X1.5.2.2 Precision should be presented as a statement where the precision is constant. XI.5.3 In view of what appears to be lower bias and better precision, Test Method D 95 should be the specified method for use in critical situations.

not permit any pair of results to be considered suspect. This is because the precision interval exceeds twice the mean value. For example, in Fig. X 1. I, the repeatability at 0.03 % water is 0.061%. It is not possible to observe a difference of more than 0.06 and still average 0.03. Thus, a pair of observations of 0,00 and 0.06 are acceptable. XI.4.4.6 Analyses of variance were performed on the data without regard to any functionality between water level and precision. The following repeatabilities and reproducibilities were found: Method

Repeat-

Reproducibility

Distillation (seven laboratories) Centrifuge (six laboratories)

0.08 0.12

0.1 I 0.28

ability

These values are almost exactly the same as the limiting values obtained by curve fitting. XI.5 Conclusions and Recommendations X 1.5.1 Data obtained in seven-laboratory round robin on measurement of basic sediment and water by the distillation test method (Test Method D 95) and the centrifuge test method (Test Method D 1796) in 21 crude oil samples were

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reepproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103.

605

Designation: D 4 0 0 7 - 81 (Reapproved 1995) ~1

An American National Standard

Designation: Manual of Petroleum Measurement Standards Chapter 10.3 (MPMS)

THt I N~TITUTF o~ P~ROI FUM

Designation: IP 359/82

Standard Test Method for Water and Sediment in Crude Oil by the Centrifuge Method (Laboratory Procedure) 1 This standard is issued under the fixed designation D 4007; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapprovai. A superscript epsilon (e) indicates an editorial change since the last revision or reapproval.

This test method has been approved by the sponsoring committees and accepted by the Cooperating Societies in accordance with established procedures. Thzs method was issued as a joint ASTM-API-IP standard in 1981. e~ No'rE--Editorial changes were made throughout in September 1995.

D 473 Test Method for Sediment in Crude Oils and Fuel Oils by the Extraction Method2 D 665 Test Method for Rust-Preventing Characteristics of Inhibited Mineral Oil in the Presence of Water2 D 1796 Test Method for Water and Sediment in Fuel Oils by the Centrifuge Method (Laboratory Procedure) 2 D4006 Test Method for Water in Crude Oil by Distillation4 D4057 Practice for Manual Sampling of Petroleum and Petroleum Products4 D 4177 Practice for Automatic Sampling of Petroleum and Petroleum Products4 2.2 API Standards: MPMS 8 "Sampling Petroleum and Petroleum Products"5 2.2 IP Standard." Specification for Toluole6

1. Scope 1.1 This test method describes the laboratory determination of water and sediment in crude oils by means of the centrifuge procedure. This centrifuge method for determining water and sediment in crude oils is not entirely satisfactory. The amount of water detected is almost always lower than the actual water content. When a highly accurate value is required, the revised procedures for water by distillation (Test Method D 4006 (Note 1)) and sediment by extraction (Test Method D 473) must be used. NOTE l - - T e s t Method D 4006 has been determined to be the preferred and most accurate method for the determination of water.

1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific precautionary statements, see 6.1 and 7.

3. Summary of Test Method 3.1 Equal volumes of crude oil and water saturated toluene are placed into a cone-shaped centrifuge tube. After centrifugation, the volume of the higher gravity water and sediment layer at the bottom of the tube is read. 4. Significance and Use 4.1 The water and sediment content of crude oil is significant because it can cause corrosion of equipment and problems in processing. A determination of water and sediment content is required to measure accurately net volumes of actual oil in sales, taxation, exchanges, and custody transfers.

2. Referenced Documents 2.1 A S T M Standards: D 95 Test Method for Water in Petroleum Products and Bituminous Materials by Distillation2 D 96 Test Methods for Water and Sediment in Crude Oil by Centrifuge Method (Field Procedure) 2 D 362 Specification for Industrial Grade Toluene 3

5. Apparatus 5.1 Centrifuge:

This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D 02,02 on Static Petroleum Measurement. Current edition approved March 27, 1981. Published May 1981. 2 Annual Book of A S T M Standards, Vol 05.01. 3 Annual Book of ASTM Standards, Vol 06.03.

4 Annual Book of A S T M Standards, Vol 05.02. 5Available from the American Petroleum Institute, 1220 L St., N.W., Washington, DC 20005. 6 Available from the Institute of Petroleum, 61 New Cavendish St., London, W.I., England.

606

D 4007 l

I'

100mE

~ 7 5

~36.00-37.75mm OD m

50

195-203mm ..

where: rpm 265 J-r-~rcf/d rcf = relative centrifugal force and d = diameter of swing measured between tips of opposite tubes when in rotating position, in. 5.2 Centrifuge Tubes--Each centrifuge tube shall be a 203-mm (8-in.) cone-shaped tube, conforming to dimensions given in Fig. 1 and made of thoroughly annealed glass. The graduations, numbered as shown in Fig. 1, shall be clear and distinct, and the mouth shall be constricted in shape for closure with a cork. Scale error tolerances and the smallest graduations between various calibration marks are given in Table 1 and apply to calibrations made with air-free water at 20"C (68"F), when reading the bottom of the shaded meniscus. 5.3 Bath--The bath shall be either a solid metal block bath or a liquid bath of sufficient depth for immersing the centrifuge tube in the vertical position to the 100-mL mark. Means shall be provided for maintaining the temperature at 60 - 3"C (140 ___5*F). =

-I 17:1: ,tumiD

m

is

1OraL

NOTE 2 - - B y contractual agreement 49 + 3"C (120 + 5*F) may be used. 82 On

_1!

SlOE

6. Solvent

6.1 Toluene (Warning--See Note 3.) conforming to Specification D 362 or to the IP Specification for Toluole. NOTE 3--Warning--Flammable.

t

LINE OF INSIDE BOTTOM

6. I. 1 Typical characteristics for this material are Molecular weight Color (APHA) Boiling range (initial to dry point)A Residue after evaporation Substances darkened by H2SO4 Sulfur compounds (as S)

INSIDE TAPER SHAPE FIG. 1

Eight-Inch (203-ram) Centrifuge Tube

5.1.1 A centrifuge capable of spinning two or more filled cone-shaped, 203-mm (8-in.) centrifuge tubes at a speed that can be controlled to give a relative centrifugal force (rcf) of a minimum of 600 at the tip of the tubes shall be used. 5.1.2 The revolving head, trunnion rings, and trunnion cups, including the cushions, shall be soundly constructed to withstand the maximum centrifugal force capable of being delivered by the power source. The trunnion cups and cushions shall firmly support the tubes when the centrifuge is in motion. The centrifuge shall be enclosed by a metal shield or case strong enough to eliminate danger if any breakage

92.14 10 2.0*(2 (36"F) 0.001% passes ACS test 0.003 %

,4 Recorded boiling point 110.6"C

6.1.2 The solvent shall be water-saturated at 60 + 3°C (140 + 5°F) (see Note 2) but shall be free of suspended water. See Annex Al for the solvent-water saturation procedure. 6.2 Demulsifier--A demulsifier should be used to promote the separation of water from the sample and to prevent its clinging to the walls of the centrifuge tube. The recommended stock solution is 25 % demulsifier to 75 % toluene. For some crude oils a different ratio of demulsifier to toluene may be required. Demulsifiers used in the concentration and quantity recommended will not add to the water and sediment volume determined. The solution must be stored in a dark bottle that is tightly closed.

OCCUrs.

5.1.3 The centrifuge shall be heated and should be controlled thermostatically to avoid unsafe conditions. It should be capable of maintaining the sample temperature during the entire run at 60 __- 3"C (140 _+ 5*F). 5.1.4 Electric powered and heated centrifuges must meet all safety requirements for use in hazardous areas. 5.1.5 Calculate the speed of the rotating head in revolutions per minute (r/min) as follows:

TABLE 1

r/rain = 1335 ,~c-f/d where: rcf = relative centrifugal force and d = diameter of swing measured between tips of opposite tubes when in rotating position, mm, or

607

C e n t r i f u g e T u b e Calibration (203-mm) Tube

Tolerances for 8-in.

Range, mm

Subdivision, mm

Volume Tolerance, mm

0 to 0.1 Above 0.1 to 0.3 Above 0.3 to 0.5 Above 0.5 to 1.0 Above 1.0 to 2.0 Above 2.0 to 3.0 Above 3.0 to 5.0 Above 5.0 to 10 Above 10 to 25 Above 25 to 100

0.05 0.05 0.05 0.10 0.10 0.20 0.5 1.0 5.0 25.0

±0.02 ±0.03 ±0.05 ±0.05 ±0.10 ±0.10 :t:0.20 ±0.50 ±1.00 ±1.00

fl~

D 4007

lEADING .

.

.

.

0 mL 9 mL 8 mL 7 mL 6 mL 5 mL 4 mL 3 mL 2 mL 1 mL 0 mL

L, - -

-1/2-

100mL

95 mL 9 mL 85 mL 8 mL 75 mL 7 mL 65 mL 6 mL 55 mL 5 mL 45 mL 4 mL 35 mL 3 mL

75

25 mL 2 mL

50

25 20

~-" -"~"

~0 mL

15 10 8 6

0 7 5 mL 0 5 mL

~ 4

025 mL

Zero

FIG. 2

Procedure for Reading Water and Sediment When Using an ASTM 100-ram Cone-Shaped Centrifuge Tube

7. Sampling 7.1 Sampling is defined as all steps required to obtain an aliquot of the contents of any pipe, tank, or other system and to place the sample into the laboratory test container. 7.2 Only representative samples obtained as specified in the API MPMS, Chapter 8 (or Practice D 4057 and Practice D 4177), shall be used for this test method.

the oil and solvent are uniformly mixed. 8.2 In the case where the crude oil is very viscous and mixing of the solvent with the oil would be difficult, the solvent may be added to the centrifuge tube first to facilitate mixing. Care must be taken in order not to fill the centrifuge tube past the 100-mL mark with the sample. 8.3 Loosen the stoppers slightly and immerse the tubes to the 100-mL mark for at least 15 min in the bath maintained at 60 _+ 3°C (140 _+50F) (see Note 2). Secure the stoppers and again invert the tubes ten times to ensure uniform mixing of oil and solvent. The vapor pressure at 600C (140OF) is approximately double that at 400C (1040F). 8.4 Place the tubes in the trunnion cups on opposite sides of the centrifuge to establish a balanced condition. Retighten the corks and spin for 10 min at a minimum relative centrifugal force of 600 calculated from the equation given in 5.1.5.

8. Procedure 8.1 Fill each of two centrifuge tubes (5.2) to the 50-mL mark with sample directly from the sample container. Then, with a pipet, add 50 mL of toluene, which has been water saturated at 60"C (140*F) or 49"C (120*F) (see Note 2). Read the top of the meniscus at both the 50 and 100-mL marks. Add 0.2 mL of demulsifier solution (6.2) to each tube, using a 0.2-mL pipet. An automatic pipettor may be used. Stopper the tube tightly and invert the tubes ten times to ensure that 608

4~ D 4007 TABLE 2

Tube 1

10. Precision 10.1 The precision of this method, as obtained by statistical examination of intedaboratory test results in the range from 0.01 to 1.0 %, is described in 10.1.1 and 10.1.2. 10.1.1 Repeatability--The difference between successive test results, obtained by the same operator with the same apparatus under constant operating conditions on identical test material, would, in the long run, in the normal and correct operation of the test method, exceed the following value in only one case in twenty: From 0.0 % to 0.3 % water, see Fig. 3. From 0.3 % to 1.0 % water, repeatability is constant at 0.12. 10.1.2 Reproducibility--The difference between two single and independent test results obtained by different operators working in different laboratories on identical test material, would, in the long run, in the normal and correct operation of the test method, exceed the following value in only one case in twenty: From 0.0 % to 0.3 % water, see Fig. 3. From 0.3 % to 1.0 % water, reproducibility is constant at 0.28.

Expression of Results, m m A

Tube 2

No visible water end No visiblewater and sediment sediment No visiblewater end 0.025 sed~lent 0.025 0.025 0.025 0.05 0.05 0.05 0.05 0.075 0.075 0.075 0,075 0.10 0.10 0.10 0.10 0.15 A For volumetrictolerances,see Table 1.

Total PercentWater and Sediment -0.025 0.05 0.075 0.10 0.125 0.15 0.175 0.20 0.25

8.5 Immediately after the centrifuge comes to rest following the spin, read and record the combined volume of water and sediment at the bottom o f each tube to the nearest 0.05 m L from 0.1 to 1-mL graduations and to the nearest 0.1-mL above 1-mL graduations. Below 0.1 mL, estimate to the nearest 0.025 m L (refer to Fig. 2). Return the tubes without agitation to the centrifuge and spin for another 10 rain at the same rate. 8.6 Repeat this operation until the combined volume of water and sediment remains constant for two consecutive readings. In general, not more than two spinnings are required. 8.7 The temperature of the sample during the entire centrifuging procedure should be maintained at 60 ± 3°C (140 ± 50F) (see Note 2). 8.8 To avoid the danger of tubes breaking in the cups, care must be taken that the tubes are bedded onto the bottom cushion so that no part of the tube is in contact with the rim of the cup.

11. Keywords 11.1 centrifuge; centrifuge tube; crude oil; laboratory procedure; sampling; sediment and water; solvent .3

I

[

I

|

I

.J

< > rr

,2 Z Z

_o _m o

W n"

9. Calculation 9.1 Record the final volume of water and sediment in each tube. If the difference between the two readings is greater than one subdivision on the centrifuge tube (see Table 1) or 0.025 m L for readings of 0.10 m L and below, the readings are inadmissible and the determination shall be repeated. 9.2 Express the sum of the two admissible readings as the percent by volume of water and sediment; report the results as shown in Table 2.

F-

~

E

A

T

A

B

I

L

I

T

Y

1

<

05

.1

.15

.2

.25

AVERAGE WATER, PERCENT, BY CENTRIFUGE FIG. 3

609

Basic Sediment and Water Precision

.3

~)

D 4007

ANNEX

(Mandatory Information) A1. PROCEDURE T O WATER-SATURATE T O L U E N E AI.1 Scope A 1.1.1 This method is satisfactory for the water saturation of toluene to be used for determination of water and sediment in crude oils by the centrifuge method.

mersing a l-(lt or 1-L bottle to its shoulder. Means shall be provided for maintaining the temperature at 60 _+ 3°C (140 +_ 5"F). A1.4.2 Glass Bottle, 1-qt or l-L, with screw top.

A1.2 Significance

A1.5 Procedure

A 1.2.1 Figure A 1.1 shows that water is soluble in toluene to a significant extent. The percent of water that will dissolve increases as the temperature is increased from about 0.03 % at 21"C (70*F) to about 0.17 % at 70"C (158"F). Toluene, as normally supplied, is relatively dry and if used in an as-received condition, will dissolve a portion of or even all of any water present in a crude oil sample. This would reduce the apparent sediment and water level in the crude sample. To determine water and sediment accurately by centrifuge on a crude oil sample, the toluene must first be saturated at the centrifuge test temperature.

A1.5.1 Adjust the heating bath to the temperature at which the centrifuge test is to be run. Maintain the bath temperature to _+3°C (50°F). AI.5.2 Fill the glass bottle with 700 to 800 mL of toluene. Add 25 mL of water. Screw the cap on the bottle and shake vigorously for 30 s. AI.5.3 Loosen the cap and place the bottle in the bath for 30 rain. Remove the bottle, tighten the cap, and shake cautiously for 30 s. AI.5.4 Repeat above procedure (A1.5.3) three times. The

vapor pressure of toluene at 60°C (140°F) is approximately twice that at 38°C (IO0°F). AI.5.4. l Allow the bottle with the water-toluene mixture to sit in the bath 48 h before using. This will ensure complete equilibrium between the toluene and the free water as well as complete saturation at the desired temperature. If it is necessary to use the water-saturated toluene before the 48-h equilibration time has been completed, the solvent must be poured into centrifuge tubes and centrifuged in the same equipment at the same relative centrifuge force and temper-

A 1 3 Reagents A1.3.1 Toluene conforming to Specification D 362 or to the IP Specification for Toluole. AI.3.2 Water, either distilled or tap water.

AI.4 Apparatus AI.4.1 Liquid-Heating Bath of sufficient depth for im-

T E M P E R A T U R E , °C

200

15 6

26.5

37 8

48 9

'

'

'

'

'

60

71 1

--

175 m

150

4 4

'

t

B

125

1 O0 m

075

--

.050

--

025

I

I

I

I

I

l

40

60

80

1 O0

120

140

TEMPERATURE,°F

FIG. A1.1

Solubility of Water in Toluene

610

160

ll~ O 4007 Keep away from heat, sparks, and open flame. Vapor harmful. Toluene is toxic. Particular care must be taken to avoid breathing the vapor and to protect the eyes. Keep container closed. Use with adequate ventilation. Avoid prolonged or repeated contact with the skin.

ature that is used for the centrifuge test. The toluene must be carefully pipetted from the centrifuge tube so that any free water that may be in the bottom of the tube is not disturbed. AI.5.4.2 Saturation is time- and temperature-dependent. It is recommended that bottles of the toluene-water mixture be kept at test temperature in the bath at all times so that saturated solvent will be available whenever tests are to be run.

A2. Precautionary Statement A2.1 Toluene--Precaution

APPENDIX

(Nonmandatory Information) XI. P R E C I S I O N AND ACCURACY OF M E T H O D S FOR D E T E R M I N I N G WATER IN CRUDE OILS

Xl.1 SummarT

TABLE X1.1

X 1.1.1 This round-robin testing program has shown that the distillation method as practiced is somewhat more accurate than the centrifuge method. The average correction for the distillation method is about 0.06, whereas the centrifuge correction is about 0.10. However, this correction is not constant nor does it correlate well with the measured concentration. X 1.1.2 There is a slight improvement in the precision of the distillation method over the present Test Method D 95: 0.08 repeatability versus 0.1 and 0.11 versus 0.2 for reproducibility. These figures are applicable from 0.1 to 1% water content, the maximum level studied in this program. X l . l . 3 The precision of the centrifuge method is worse than the distillation: repeatability is about 0.12 and the reproducibility 0.28.

X 1.2.1 In view of the economic importance of measuring the water content of crude oils precisely and accurately, a working group of API/ASTM Joint Committee on Static Petroleum Measurement (COSM) undertook the evaluation of two methods for determining water in crudes. A distillation method (Test Method D 95) and a centrifuge method (Test Method D 1796) were evaluated in this program. Both methods were modified slightly in an attempt to improve the precision and accuracy.

X1.3 Experimental X l.3.1 Samples--The following seven crude oils were obtained for this program: Crude

Source Texaco Mobil Williams Pipe Line Exxon Texaco Koch Industries Gulf

~ H~O

San Ardo Arabian Light Alaskan Arabian Heavy Minas Fosterton Nigerian

0.90 0.15 0.25 0.10 0.50 0.30 <0.05

tion. The entire concentration range studied was from zero to 1.1% water. These expected values were used to determine the accuracy of the test procedures. X1.3.2 Sample Preparation: X1.3.2.1 The crude oils were received from the suppliers in barrels. After mixing by rolling and turning, two 5-gal samples and one 250-mL sample were taken from each barrel. The Minas crude had to be heated to 150OF with a barrel heater before samples could be drawn. The 250-mL samples of each crude, as received, were used to establish the base case in water content. Each sample was analyzed by Test Method D 95 to determine the water content. These starting points are shown in Table X 1.1. X 1.3.2.2 To obtain "water-free" samples of crude oil, one 5-gal sample of each o f two crudes was distilled over the temperature range of initial to 300°F vapor temperature. This distillation was done using a 15 theoretical plate column at 1:1 reflux ratio. X1.3.2.3 "Spiking" samples to a known water concentration was done using synthetic sea water (as described in Test Method D 665). The mixing and homogenization was done with a static Mender. The complete listing of samples with their expected water contents is shown in Table X 1.2. X 1.3.2.4 The samples for each cooperator were bottled so that the entire sample had to be used for a given test. In this way, any effect due to settling or stratification of water was eliminated. X1.3.2.5 Samples were coded to mask the presence of duplicates and a table of random numbers dictated the running order of tests. XI.3.2.6 The participating laboratories were: Chevron Research Co.

Xl.2 Introduction

San Ardo Arabian Light Alaskan Arabian Heavy Minas Fosterton Nigerian

Base Case--Water Content of Crudes

Crude Oil

By removing all water or adding known amounts of water to the above crudes, 21 samples were prepared for testing. Each crude oil was represented at three levels of water concentra611

fl~ D 4007 TABLE X l . 2 Crude Source

Water Content of Crude Oil Samples Found

Added

Expect

San Ardo

0.90

Arabian Light

0.15

Alaskan

0.25

0 dried dried + 0.4 0 0.10 O.9O 0 0.20 0.80 0 dried dried + 0.1 0 0.10 0.50 0 0.20 0.30 0 0.40 0.80

0.90 0.0 0.40 0.15 0.25 1.05 0.25 0.45 1.05 0.10 0.0 0.10 0.50 0.60 1.00 0.30 0.50 1.10 <0.05 0.45 0.85

Arabian Heavy

0.10

Minas

0.50

Fosterton

0.30

Nigerian

0.05

Determination of Water in Crude Oils, % H=O

TABLE X l . 3

% H20

Expected

Distillation

Centrifuge

0.90 0.0 0.40 0.15 0.25 1.05 0.25 0.45

0.90 0.04 0.42 0.10 0.21 0.86 0.21 0.39 0.92 0.11 0.08 0.18 0.45 0.53 0.96 0.18 0.33 0.86 0.02 0.35 0.65

0.79 0.05 0.021 0.12 0.13 0.78 0.14 0.32 0.98 0.04 0.02 0.10 0.34 0.47 0.97 0.07 0.20 0.77 0.01 0.32 0.65

1.05 0.10 0.0 0.10 0.50 0.60 1.00 0.30 0.50 1.10 0.05 0.45 0.85

it was decided that data obtained by Test Method D 95 in one laboratory would be the "true value." Table X1.3 shows the expected value compared to each sample average using this criterion. It can be seen that both methods are biased low. However, the distillation test method (Test Method D 95) appears less biased than the centrifuge. Since the bias is not the same in every laboratory (Table X I.4), it is not possible to recommend inclusion of a correction factor in the methods. This data treatment suggests that the centrifuge method, on the average, yields results about 0.06 % lower than the distillation. The respective biases are -0.13 for the centrifuge and -0.07 for the distillation method. XI.4.1.3 A more reliable estimate of bias may be obtained if consideration is given only to those samples to which water was added. In this case, the measured differences between the unspiked sample and the spiked sample compared to the actual water added would be indicative of the bias. Table XI.5 shows these differences for each method. On this basis the centrifuge bias has improved slightly, while the distillation is about the same. The difference between the two methods is now 0.04 rather than 0.06. It should be noted that bias is greatest with both methods at higher water content. XI.4.2 Precision: XI.4.2.1 To estimate the precision of the tests, the data

Exxon Research and Engineering Co. Mobil Research and Development Corp. Texaco, Inc. Shell Charles Martin, Inc. Gulf Research and Development Co. X1.3.3 Test Modifications--The base methods studied were modified slightly in an effort to improve the performance. The modifications were as follows: X1.3.3.1 Test Method D 95--Sample size was standardized at 200 g and the solvent volume was increased to maintain the original solvent/sample ratio. X 1.3.3.2 Test Method D 1796--A heated centrifuge (held near 140°F) and use o f a demulsifier were mandatory. Eight-inch centrifuge tubes were also specified. Toluene saturated with water at 60°C (140°F) was the only permissible solvent. The demulsifier used was a Tret-O-Lite material, F65. 7

Xl.4 Results and Discussion X1.4.1 Accuracy: X I.4.1.1 Accuracy or bias is defined as the closeness of the measured value to the "true value." Since there is no independent absolute method available to determine this true value for these samples, some other means must be used. Two options were considered: (1) Select one laboratory and one method as the "reference system" and define these results as the true value, or (2) Spike samples with known amounts of water. The measured difference between the original and unspiked samples can be compared to the known added water to determine the bias (accuracy). Both approaches were investigated in this study. X1.4.1.2 Since Test Method D 9 6 defines the base method as a combination of Test Methods D 95 and D 473,

TABLE X l . 4

Corrections to be Applied to Measured Values to Obtain "True" Water Content

Method

Laboratory

D 1796 Centrifuge

C E M T S I G Average C E M T S I G

D 95 Distillation

7 Tret-O-Lite is a registered trademark of Tretolite Div., Petrolite Corp., 369 Marshall Ave., St. Louis, MO. Even though Tret-O-Lite F65 was used during the round robin, there are many demulsifiers on the market that may be useful.

Average

612

Correction +0.152 + +0.029 ± +0.196 + +0.196 + +0.160 + +0.116 + +0.121 + +0.132 +0.777 + +0.048 + +0.082 + +0,064 + +0.077 + +0.081 + +0.072 ± +0.069

0.095 0.125 0.135 0.100 0.122 0.126 0.115 0.082 0.078 0.077 0.079 0.107 0.112 0.096

(1~ D 4007 TABLE X1.5

X1.4.2.2 Seven laboratories participated in the round robin. Basic sediment and water was measured on 21 crude oil samples in duplicate by the distillation test method (Test Method D 95) and the centrifuge test method (Test Method D 1796). The raw data are presented in Table X 1.6. X1.4.3 Test for Outliers Procedures for rejecting outliers recommended in ASTM RRD-2 1007, "Manual on Determining Precision Data for ASTM Methods on Petroleum Products and Lubricants," were followed. XI.4.3.1 Distillation Method--The following table lists the outliers rejected and the substituted values: Laboratory Sample Rejected Value SubstitutedValue 1 14 0.75 0.53 3 3 0.35, 0.54 0.445 2 11 0.34 0.05 6 13 0.66 0.45 6 15 1.37 0.85

Bias of Methods Estimated from Spiked Samples D 95

Water Added,A

D 1796

Found

&

Found

A

0.10 0.08 0.10 0.16 0.15 0.39 0.33 0.49 0.70 0.70 0.64 0.76

0 -0.02 0 -0.04 -0.05 -0.01 -0.07 -0.01 -0.10 -0.10 -0.16 -0.14 -0.06

0.05 0.00 0.10 0.16 0.12 0.16 0.30 0.52 0.73 0.70 0.63 0.69

-0.05 -0.10 0 -0.04 0.00 -0.24 -0.10 +0.02 -0.07 -0.10 -0.17 -0.21 -0.10

0.10 0.10 0.10 0.20 0.20 0.40 0.40 0.50 0.80 0.80 0.80 0.90 Average

A Equal water additions shown are to different crude oils.

were analyzed following the ASTM guidelines published as Research Report R R D-2 1007, "Manual on Determining Precision Data for ASTM methods on Petroleum Products "4 (1973). TABLE Xl.6

X1.4.3.2 Centrifuge Method." The data from Laboratory 5 were rejected outright because incorrect-size centrifuge tubes were used (letter, Shell Oil to E. N. Davis, cc: T o m Hewitt,

Round-Robin Results of Water in Crude Oils by ASTM D 95 and ASTM D 1796 Distillation Test Method ASTM D 95

Laboratodes

Samples 1

9

15

6

18

0.86 0.86

0.90 0.92

0 . 9 1 0 . 9 1 0.88 0.92 0.86 0.85

0.90 0.91

0.94 0.94

0.99 1.00

0.90 0.92

0.80 0.85

0.94 0.94

0.98 0.98

0.93 0.93

2

11

19

3

8

13

14

17

20

21

4

0.00 0.02 0 . 0 1 0.02

0.05 0.02

0.40 0.39

0.39 0.40

0.46 0.46

0.75 0.53

0.25 0.38

0.35 0.33

0.67 0.66

0.10 0.09

5

0.90 0.90

0.05 0.06

0.34 0.06

0.04 0.94

0.43 0.48

0.40 0.40

0.46 0.47

0.63 0.58

0.39 0.36

0.35 0.30

0.70 0.69

0.09 0.25 0 . 1 1 0.24

0.65 0.83

0.90 0.90

0.05 0.02

0.00 0.03

0.00 0.00

0.35 0.54

0.38 0.40

0.45 0.43

0.43 0.55

0.35 0.33

0.33 0.33

0.65 0.65

0.92 0.90

0.89 0.90 0 . 9 1 0.89

0.88 0.90

0.07 0.07

0.02 0.02

0.05 0.04

0.42 0.42

0.40 0.39

0.42 0.43

0.52 0.52

0,35 0.33

0.36 0.35

0.87 0.86

0.88 0.92

0.87 0.83

0.86 0.80

0.86 0.80

0.07 0.07

0.07 0.09

0.05 0.04

0.39 0.39

0 . 4 1 0.42 0.40 0.37

0 . 5 1 0.23 0.47 0.35

0.98 1.01

0.94 0.94

0.85 1.37

0.79 0.84

0.74 0.89

0.04 0.02 0 , 0 1 0.00

0.05 0.58 0 . 0 1 0.48

0.39 0.80

0.45 0.66

0.44 0.56

0.91 0.97

0.63 0.92

0.97 1.03

0.85 0.64

0.80 0.80

0.05 0.02

0 . 0 1 0 . 0 1 0.42 0.13 0 . 0 1 0.39

0.40 0.35

0 . 4 1 0.53 0.46 0.47

7

10

0.15 0.20 0.18 0 . 2 1 0 . 2 1 0.20

12

16

0.13 0.13

0.18 0.15

0.25 0.25

0.18 0.19

0 . 1 1 0.20 0.14 0.20

0.07 0.10

0.2"0 0.23 0.15 0.23

0.18 0.15

0.05 0.07

0.66 0.67

0.10 0.10

0.19 0.20

0.18 0.16

0.10 0.20 0 . 1 1 0.19

0.39 0.35

0.65 0.50

0 . 1 1 0 . 2 1 0 . 2 1 0 . 2 1 0.16 0.12 0.20 0.24 0.24 0.18

0.20 0.16

0.36 0.30

0.38 0.39

0.61 0.66

0 . 1 1 0.24 0.13 0.25

0.23 0.24

0.20 0.07 0 . 2 1 0.05

0.24 0.18

0.34 0.35

0.36 0.38

0.64 0.65

0.05 0.15

0.18 0.23

0.15 0.15

21

4

0.18 0.20

0.23 0.19

0.15 0.16

0.18 0.18 0 . 1 1 0.15

Centrifuge Test Method D 1796 Laboratories

Samples

1

9

15

0.82 0.79

0.90 0.89

0.87 0.88

1.03 0.88

6

18

2

11

19

3

8

0.80 0.70 0 . 8 1 0.74

0.05 0.05

0.02 0.02

0.00 0.02

0.23 0.23

5

7

10

12

16

0.46 0.19 0 . 4 1 0.17

0.27 0.29

0.65 0.02 0 . 6 1 0.02

0.07 0.06

0.05 0.06

0.03 0.05

0.02 0.02

0.02 0.04

1.09 1.05 1 . 1 1 1.12

0.74 0.74

0.95 1.00

0.19 0.05

0.07 0.05

0.00 0.00

0.19 0.40 0 . 3 1 0.43

0.50 0.38

0.58 0.60

0.38 0.34

0.45 0.50

0 . 6 1 0.15 0.20 0.85 0 . 2 1 0.37

0.20 0.42

0.20 0.17

0.06 0.06

0.20 0.04

0.65 0.60

0.80 0.85

0.90 0.90

0.70 0.60

0.70 0.70

0.07 0.07

0.00 0.00

0.05 0.02

0.10 0.10

0.30 0.34

0.30 0.40

0.42 0.50

0.05 0.10

0.20 0.20

0.60 0.45

0.02 0.02

0.02 0.02

0.07 0.12

0.02 0.02

0.05 0.00

0.02 0.02

0.73 0.79

0.95 1.00

0.88 0.90

0.85 0.75

0.80 0.70

0.00 0.00

0.00 0.00

0.05 0.05

0.18 0.16

0.27 0.27

0.33 0.40

0.46 0.45

0.15 0.15

0.30 0.27

0.63 0.55

0.00 0.00

0.10 0.05

0.10 0.13

0.05 0.05

0.05 0.00

0.05 0.05

0.69 0.76

1.55 1.10

0 . 5 1 0.87 0.87 0.93

0.83 0 . 0 1 0.03 0 . 4 1 0 . 0 1 0.05

0.03 0.02

0.18 0.30

0 . 2 1 0.16 0.54 0.20

0.30 0.07

0 . 2 1 0.39 0.72 0.19 0 . 0 1 0.69

0.75 0.06

0.13 0 . 0 1 0 . 2 1 0.03 0 . 1 1 0.02 0.09 0.03

0.05 0.12

0.72 0.86

0.75 0.90

1.59 1.44

0.85 0.65

0.65 0.65

0.07 0.09

0.05 0.05

0.05 0.05

0.35 0,32

0.33 0.25

0,25 0.38

0.52 0.52

0.20 0.25

0.45 0.38

0 . 7 5 0 . 0 5 0.15 0.80 0.10 0.10

0.05 0.13

0.05 0.10

0.05 0.05

0.05 0.10

0.88 0.90

1.00 0.85

0.85 0.80

0.85 0.80

0.70 0.80

0.00 0.05

0.00 0.00

0.05 0.05

0.15 0.10

0.20 0.35

0.30 0.30

0.40 0.35

0.25 0.13

0.23 0.25

0.63 0.60

0.25 0.30

0.20 0.15

0.00 0.00

0.18 0.10

13

0.25 0.38 0 . 3 1 0.35

613

14

17

20

0.10 0.18

0.18 0.20

~ 1

I

D 4007

I

I

1

I

J

Oll

J

O.10 ~: 009 ~> 008

i

zo 007 0.06 ~0.O5 0.04 0 03 0 o2 001

I

0 0

0 01

1

I

I

I

I

I

0.02 0.03 0 04 0.05 0.06 0.07 AVERAGEWATER, PERCENT,BY DISTILLATION

I

0.08 0.085

FIG. X1.1 Basic Sediment and Water Precision for ASTM Test Method D 95 Distillation (Based on Seven laboratories)

February 9, 1979). Statistical tests showed that laboratory 5's data did not belong to the same population as the other data. (a) Laboratory 2's data were also suspect and did not appear to belong to the same population as the other data. However, it was learned that Laboratory 2's results were closest to actual levels of water added to the samples. There is, therefore, a dilemma on whether or not to reject Laboratory 2's data. As a compromise, precision was calculated with and without Laboratory 2's results. The following table lists the outliers rejected and the substituted values when Laboratory 2's results are retained: Laboratory

Sample

Rejected Value

Substituted Value

2 2 2 6 6

2 7 21 6 15

0.19 0.42 0.85 0.65 1.59, 1.44

0.06 0.20 0.61 0.85 0.922

S = A x ( I - e "M)

where: S = precision, = sample mean, and A and b are constants. was found to best fit the data. The values of the constants A and b were calculated by regression analysis of the linear logarithmic equation: log S = log A/log( 1 - e-t'R') XI.4.4.2 The standard deviation for repeatability for each sample was calculated from pair-wise (repeat pairs) variances pooled across the laboratories. The standard deviation for reproducibility was calculated from the variance of the mean values of each pair. This variance is equal to the sum of two variances, the variance aL2 due to differences between laboratories and the variance due to repeatability error az.2 divided by the number of replicates: a, 2 = a ) / n + az2(n = 2)

(b) With Laboratory 2's results omitted, only Laboratory 6's results listed above were rejected. XI.4.4 Calculation o f R e p e a t a b i l i t y a n d Reproducibility: X1.4.4.1 Repeatability and reproducibility were obtained by fitting curves of the appropriate precision of the results on each sample versus the mean value of each sample. An equation of the form: o 20

I

I

I

Using the data calculated above for each sample, the following values for the constants in Eq 1 were obtained:

I

l

~

n.-

~015

I

I

I

1

REPRODUCIBILITY

Z Z

o ~OlO

REPEATABILITY

LM n"

:~005 I,-

0 0

I 0 02

I I I I I I I I 0 04 0 . 0 6 0.08 0 10 0 12 O 14 0 . 1 6 0.18 AVERAGEWATER, PERCENT,BY CENTRIFUGE

FIG. X1.2 Basic Sediment and Water Precision for ASTM Test Method D 1796 Centrifuge (Based on Five laboratories)

614

tl~ D 4007 0,30

f

I

I

I

I

I

|

I

0 25

o 20 z

_o o 1 5 0 iii

" 010

O05~f

0 0

I

I

I

I

I

I

I

002

004

006

0.08

0.10

012

014

I 016

I 018

AVERAGE WATER, PERCENT, BY CENTRIFUGE

FIG. Xl.3

Basic Sediment and Water Precision for ASTM Test Method D 1796 Centrifuge (Based on Six Laboratories)

Distillation Method 7 Laboratories Repeatability Reproducibility

n o t p e r m i t a n y p a i r o f results to b e c o n s i d e r e d suspect. T h i s is b e c a u s e t h e p r e c i s i o n i n t e r v a l exceeds t w i c e t h e m e a n value. F o r e x a m p l e , in Fig. X 1.1, t h e r e p e a t a b i l i t y at 0.03 % water is 0 . 0 6 1 % . It is not possible to observe a difference of

Constant

b A

47.41 47.41 0.2883 0.0380 Centrifuge Method 6 Laboratories Repeatability Reproducibility

more than 0.06 and still average 0.03. Thus, a pair of observations of 0.00 and 0.06 are acceptable. X1.4.4.6 Analyses of variance were performed on the data without regard to any functionality between water level and precision. The following repeatabilities and reproducibilities were found:

Constant

b A

11.23 0.0441

11.23 0.1043

Method

5 Laboratories Repeatabihty Reproducibility

Distillation (seven laboratories)

Constant

b A

17.87 0.0437

Centrifuge (six laboratories)

17.87 0.0658

TABLE Xl.7

The values of precision calculated by Eq 1 were multiplied by 2.828 (2 x ~ ) to convert them to the ASTM-defined repeatability and reproducibility. X1.4.4.3 The curves of repeatability and reproducibility for the distillation method in the range 0 to 0.09 % water are shown in Fig. XI.I. These data are also tabulated in Table XI.7. The curves for the centrifuge method in the range 0 to 0.2 % water are shown in Fig. X1.2 (five-laboratory case) and Fig. XI.3 (six-laboratory case). XI.4.4.4 For higher levels of water the limiting repeatabilities and reproducibilities are: Method Distillation Centrifuge (five-laboratorycase) Centrifuge (six-laboratory case) Method Distillation Centrifuge (five-laboratorycase) Centrifuge (six-laboratory case)

Repeat-

% Water 0.000 0.005 0.010 0.015 0.020 0.025 0.030 0.035 0.040 0.045 0.050 0.055 0.080 0.065 0.070 0.075 0.080 0.085 0.090 0.095 0.100 0.105 0.110 0.115 0.120 0.125 0.130

Repeatability Range of Concentration, % Value, % _>.085 0.08 _>.155 0.12 ->.235 0.12 Reproducibility Range of Concentration, % Value, % ->0.085 0.105 ->0.325 0.19 ->0.315 0.29

X1.4.4.5 It should be pointed out that at the lowest water levels, the precision "statements" for some of the analyses do

615

ability 0.08

0.12

Reproducibility 0. I I

0.28

ASTM Precision Intervals: ASTM D 95 (7 Laboratodes)

Repeatability 0.000 0.017 0.030 0.041 0.049 0.056 0.061 0.065 0.068 0.071 0.073 0.074 0.075 0.076 0.077 0.078 0.078 0.079 0.079 0.079 0.079 0.079 0.080 0.080 0.080 0.080 0.080

Reproducibility 0.000 0.023 0.041 0.055 0.066 0.075 0.082 0.087 0.091 0.095 0.097 0.1 O0 0.101 0.103 0.1 04 0.1 04 0.105 0.106 0.106 0.106 0.107 0.107 0.107 0.107 0.107 0.107 0.107

% Water 0.000 0.005 0.010 0.015 0.020 0.025 0.030 0.035 0.040 0.045 0.050 0.055 0.060 0.065 0.070 0.075 0.080 0.065 0.090 0.095 0.100 0.105 0.110 0.115 0.120 0.125 0.130

I~) D 4007 These values are almost exactly the same as the limiting values obtained by curve fitting.

(c) Above 0.1% water, the repeatability is 0.08 and the reproducibility is 0.11.

X 1.5.1.2 Centrifuge Method: (a) Repeatability is related to water content up to about 0.2 % water and reproducibility up to about 0.3 %. (b) In the range 0.01 to 0.2, repeatability varies from 0.01 to 0.11 and reproducibility in the range 0.02 to 0.3 from 0.03 to 0.28. X1.5.2 It is recommended that: XI.5.2.1 Precision should be presented as a graph in the range where precision varies with water content. X1.5.2.2 Precision should be presented as a statement where the precision is constant. X1.5.3 In view of what appears to be lower bias and better precision, Test Method D 95 should be the specified method for use in critical situations.

X1.5 Conclusions and Recommendations XI.5.1 Data obtained in seven-laboratory round robin on measurement of basic sediment and water by the distillation test method (D 95) and the centrifuge test method (D 1796) in 21 crude oil samples were examined. The conclusions are: X1.5.1.1 Distillation Method: (a) Precision is related to water content up to about 0.08 % water. (b) In the range from 0.01 to 0.08, repeatability varies from 0.020 to 0.078 and reproducibility from 0.041 to 0.105.

The American Society for Testing and Materials takes no position respecting the vahdlty of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determmation of the vahdtty of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is sublect to revision at any time by the responsible technical committee and must be reviewed every hvo years and tf not revised, either reapproved or withdrawn Your comments are mvtted either for rewslon of this standard or for additional standards and should be addressed to ASTM Headquarters Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend If you feel that ,/our comments have not received a lair hearing you should make your views known to the ASTM Committee on Standards, 100 Barr Herbor Drive, West Conshohocken, PA 19428

616

q~l~ Designation:D 4045 - 96

An American National Standard

Standard Test Method for Sulfur in Petroleum Products by Hydrogenolysis and Rateometric Colorimetry 1 This standard is issued under the fixed designation D 4045; the number immediately following the designation indicates the year of original adoption or, in the ease of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (~) indicates an editorial change since the last revision or reapproval.

1. Scope 1.1 This test method covers the determination of sulfur in petroleum products in the range from 0.02 to 10.00 mg/kg. 1.2 The method may be extended to higher concentration by dilution. 1.3 The method is applicable to liquids whose boiling points are between 30 to 371"C (86 and 700*F). Materials that can be analyzed include naphtha, kerosine, alcohol, steam condensate, various distillates, jet fuel, benzene, and toluene. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

2. Referenced Documents

2.1 ASTM Standards: D 1193 Specification for Reagent Water 2

3. Summary of Test Method

3.1 The sample is injected at a constant rate into a flowing hydrogen stream in a hydrogenolysis apparatus. The sample and hydrogen are pyrolyzed at a temperature of 1300"C or above, to convert sulfur compounds to hydrogen sulfide (H2S). Readout is by the rateometric detection of the colorimetric reaction of H2S with lead acetate. Condensable components are converted to gaseous products such as methane during hydrogenolysis.

4. Significance and Use

4. I In many petroleum refining processes, low levels of sulfur in feed stocks may poison expensive catalysts. This method can be used to monitor the amount of sulfur in such petroleum fractions. 4.2 This method may also be used as a quality-control tool for sulfur determination in finished products. This test method is under the jurisidiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee I)02.03 on Elemental Analysis. Current edition approved Nov. 10, 1996. Published January 1997. Originally published as D 4045 - 87. Last previous edition D 4045 - 92 El. 2 Annual Book of ASTM Standards. Vol I 1.01.

617

5. Apparatus a,4 5.1 Pyrolysis Furnace--A furnace that can provide an adjustable temperature of 900 to 1400"C in a 5-mm inside diameter or larger tube is required to pyrolyze the sample. The furnace entry temperature must allow insertion of the hypodermic tip to a depth at which the temperature is 550"C to provide sample vaporation at the injection syringe tip. This temperature must be above the boiling point of the sample and of the sulfur compounds in the sample (see Fig. 1). The pyrolyzer tube may be of quartz; however, the lifetime is limited above 1250"C. Ceramic may be used at any temperature. 5.2 Rateometric H:,S Readout--Hydrogenolysis products contain H2S in proportion to sulfur in the sample. The H2S is measured by measuring rate of change of reflectance caused by darkening when lead sulfide is formed. Rateometric electronics, adapted to provide a first derivative output, allows sufficient sensitivity to measure below 0.1 mg/L (see Fig. 2). 5.3 Hypodermic Syringe--A hypodermic having a needle long enough to reach the 5500C zone is required. A side port is convenient for vacuum filling and for flushing the syringe. A 100-1xL syringe is satisfactory for injection rates down to 3 I~L/min and a 25-~tL syringe for lower rates. NOTE h Warning--Exercise caution as hypodermicscan cause accidental injury.

5.4 Syringe Injection Drive--The drive must provide uniform, continuous sample injections. Variation in drive injection rate caused by mechanical irregularities of gears will cause noise. The adjustable drive must be capable of injection from 6 ~tL/min to 0.06 ~tL/min over a 6-min interval. 5.5 Recorder--A chart recorder with 10-V full scale and 10 000-[2 input or greater is required having a chart speed of 0.2 to 1 in./min (approximately 0.5 to 3 cm/min). An attenuator can be used for more sensitive recorders. 5.6 Thermocouple--A thermocouple suitable for use at 500 to 1400"C, 250 mm long with readout is required. Type K, 1/16-in. (l.6-mm) diameter, Type 316 stainless steel sheath is suitable. 3 The apparatus described in 5. I to 5.4 inclusive is similar in specification to the equipment available from Houston Atlas, Inc., 22001 North Park Dr., Kingswood, TX 77339-3804. For further information see Drushel, H. V., "Trace Sulfur Determination Petroleum Fractions," Analytical Chemistry, Vol 50, 1978, p. 76. 4 Houston Atlas, Inc. is the sole source of supply of the apparatus known to the committee at this time. If you are aware of alternative suppliers, please provide this information to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, I which you may attend.

~) DISPOSABLE CERAMIC OR QUARTZREACTION TUBE BALSTON

SAMPLE TO825RFOR TOTALSULFUR READOUT

D 4045

INJECTIONOFLIQUIO (n:m CONTROLLED RATE SYRINGE

PYROLYZER®

~ ' q

HU"IOIFIER / II~

GAS WASHBOTTLE ~ ~

~ L ~ L

~l 1N|

kNI INi

il/ CARRIERH2 NOTE~Thehumidifiergas wash bottle is optional.

FIG. 1 HydrogenolysisFlow Diagram

UNGSTENLA4-SAMPLEFROM PYROLYZER®

,0c,,sINGLcJ

:D

(::=

FINE ,ocus RALANCINg 1l:Ng

F TOR

WINDOW

FIG. 2 PhotorateometryH=S Readout 6. Reagents and Materials

6.1 Purity of Reagents--Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society where such specifications are available, s Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without s Reagent Chemicals, American Chemical Society Specifications, American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed by the American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Peele, Dorset, U.K., and the United Stales Pharmacopeia and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.

618

lessening the accuracy of the determination. 6.2 Purity of Water--Unless otherwise indicated, references to water shall be understood to mean Type II reagent grade water conforming to Specification D 1193. 6.3 Sensing Tape--Lead acetate impregnated paper of chromatographic quality shall be used. NOTE 2: Warning--Lead is a cumulative poison. 6.4 Hydrogen--As no commercial grade of hydrogen has a sulfur specification sufficiently low, each new source of supply must be tested. A change in the zero base line of 5 % of full scale from no flow to full flow indicates impure hydrogen. NOTE 3: Wm~ing--Extremely flammable gas under pressure. NOTE 4: Warning, Precution--Hydrogen is a flammable gas. Test all flow systems for leaks and purge with inert gas before introducing hydrogen and after removing hydrogen. Keep all flow systems as small in volume as practical and provide protective screening for containers other than sample flow lines. Dispose of exhaust gases in a fume hood or by vacuuming to a safe area. If gas cylinders are used handle carefully as rupture of the valve or cylinder is dangerous. 6.5 Reference Standards: 6.5. l Isooctane--ASTM Knock Test Reference Fuel. 6 NOTE 5: Warning--Extremely flammable. NOTE 6--1scociane is to be used as a solvent for sulfur compounds. Test each new lot for sulfur by this procedure as specifications are not rigorous enough for this application, n-heptane or equivalent material may be used. 6.6 Acetic Acid Solution--Mix glacial acetic acid 1 part by volume to 19 parts distilled water. NOTE 7: Warning--Corrosive. 6.7 Di-n-Butyl Sulfide (CH3CH2CH2CH2)2S) is used to prepare standards. Equivalent sulfur compound may be used if care is exercised to prevent more volatile compounds from evaporating during preparation or use of standards. 6.8 Helium or Nitrogen Purge Gas NOTE 8: Warning--Compressedgas under high pressure. Availablefrom PhillipsPetroleumCo., P.O. DrawerO, Borger,TX 79071.

~[~) O 4045 7. Calibration Standard 7.1 Prepare a reference standard-solution or solutions of strength near that expected in the unknown. Measurements can be made by weight or by volume for carder liquid. 7.2 Units of sulfur in milligrams per litre of sample are preferred as this is independent of the density of the carder liquid. The following equation is used to calculate the volume of solvent required to dissolve a precise weight of sulfur compound, of known composition and purity to prepare a liquid standard: z ffi

x d × e x 10 6 I(a)

or alternatively:

a ffi ( b x d x e x 106)/(z)

sulfur compounds. Volumetrically dilute stock to prepare low-level standards. 8. Preparation of Apparatus 8.1 Turn on the furnace with temperature controls at minimum. Gradually increase furnace control over a 3-h period to approximately 13000C to minimize thermal shock. Reverse the procedure when preparing for long-term storage. For shutdown at night and weekends reduce temperature to about 900°C but do not turn off the furnace. Furnace and quartz tubing life are extended by not cooling to room temperature. 8.2 Connect all tubing and fill prehumidifier outside the cabinet with distilled water if this apparatus is being used, and final humidifier inside the cabinet with 5 % by volume acetic acid solution. Purge with inert gas then close valve. Check all connections with soap solution and repair any leaks. Set hydrogen flow at 200 mL/min and allow temperature to stabilize. (Warning--see Note 3). Make final temperature adjustment to 1315 + 15"C. Use a standard thermocouple to verify temperature by inserting through a septum with hydrogen flowing at the rate noted above. Determine depth of insertion required and always insert the hypodermic tip to the 550"C point (see 8.6). NOTE 9: Warning--The use of a humidifiergas wash bottle filled with approximately 250 mL of distilled water is a potential safety hazard, as hydrogenpressure may build up inside the container. The user of the test method should take appropriate safety measures to prevent an accidentalinjury,if the humidifiergas wash bottle is used in the analysis.

(1)

(2)

where: a = desired concentration of sulfur, mg/L, of the standard solution of z millilitre of volume, b = molecular weight of sulfur: 32.06, c = molecular weight of the sulfur compound to be used to prepare the standard. d = mass of the sulfur compound used to prepare the standard, g, e = purity of sulfur c o m p o u n d expressed as a decimal, and z -- millilitres of standard solution required to give the desired concentration a.

Example: Calculate the volume of sulfur free isooctane with volume of sulfur compound necessary to dissolve 0.5013 g of 98 % by weight di-n-butyl sulfide to obtain a standard containing 1000 mg/L of sulfur in a solution. a = 1000 mg/L b = 32.06 c = 146.29 di-n-butyl sulfide (CH3CH2CH2CH2)2S d = 0.5013 g e ffi 0.98 [32.06/146.29 x 0.5013 x 0.98 x 106 z -ffi 107.66 mL 1000

8.3 Prepare the sample injection drive. Check to be sure desired injection rate is obtained at various settings. Verify that erratic pulses of fast drive do not occur when the drive range is switched. Pulses of high sample flow above 15 ~tL/min will cause carboning and spurious readings. 8.4 Install sensing tape and turn H2S readout analyzer on. 8.5 Connect the recorder and adjust the zero to desired position with hydrogen flowing. 8.6 Fill syringe with blank reference standard solution, typically isooctane, insert the needle through the septum to the 550°C temperature zone and clamp to the syringe drive. At high temperature the hot needle may absorb sulfur and at lower temperature heavy compounds may not evaporate. Set the syringe drive rate desired, normally 6 ttL/min, maximum with 200 mL/min hydrogen flow. Drive rate may be increased for increased sensitivity up to the point at which carbon is formed. (Hydrogen flow at 500 mL/min allows injection of 15 ttL/min; however, dibenzothiophene conversion will be low.)

Isooctane is added to bring the solution to a total volume of 107.66 mL. When results are to be reported in mass of parts per million mg/kg, the conversion from milligrams per litre should be done as the last step in the calculations. 7.3 To prepare a sulfur standard with a sulfur concentration of I000 mg/L as previously described, obtain a clean 125-mL glass container, a 100-mL flask, and a 20-mL graduated glass pipet. Rinse each thoroughly with isooctane (2,2,4-trimethylpentane). (Warning--see Note 3). Pour approximately 90 mL of isooctane into the 100-mL flask. Weigh approximately 0.5 g of di-n-butyl sulfide directly into the flask and record the mass added, to +50 ttg. Add additional isooctane to the flask to 100 mL. Transfer the mixture to the 125-mL container and add isooctane equal to the difference of z minus 100 mL. Keep containers closed as much as possible. Do not open containers of pure sulfur compound in the vicinity of sulfur free stocks or low-level standards. Evaporation from containers of pure sulfur compounds can contaminate other nearby liquids. This is particularly troublesome when working below I mg/L near volatile

9. Calibration and Standardization

9.1 With hydrogen flow at 200 mL/min, advance new tape and note baseline. Adjust the offset up scale about 5 % to be clear of the recorder stops. Record the stable reading average value as the zero sulfur reference and record as Rb in 11. I. There will be essentially no difference in reading with or without hydrogen flow and with or without blank injection, if blank and hydrogen have no sulfur. 9.2 Advance the tape and inject a reference material with a sulfur concentration near that expected in the unknown. Aider about 4 rain injection time adjust the recorder span for 619

~

D 4045

approximately 90 % of scale. Record the average reading as Rstd in I0.I.

apparatus under constant operating conditions on identical test material would, in the long run, in the normal and correct operation of the test method, exceed the following values only in one case in twenty (see Table 1). Repeatability = 0.16 VfX where X -- average value of two results, mg/kg. 12.1.2 Reproducibility--The difference between two single and independent results obtained by different operators working in different laboratories on identical test material would, in the long run, exceed the following values only in one case in twenty (see Table 1). Reproducibility = 0.26 ,fX NOTE 10---One laboratory conducted a statistical evaluation by analyzing the same sample (with a nominal sulfur concentration of 0.2 ppm), using multiple technicians and the same instrumentation, with and without the humidifier gas wash bottle installed, and determined that results were statistically equivalent for both precision and accuracy at the 95 % confidence interval. Results of the statistical evaluation are available from ASTM Headquarters. Request RR:D02-1405.

10. Procedure 10.1 Advance the tape and inject the unknown sample. After a stable reading is obtained record this average value as Rsin 11.1. 10.2 Proceed with additional samples. Every 2 h or as needed, verify blank and span values. 10.3 To measure sulfur below I rag/L, inject the sample at the maximum rate, normally 6 ttL/min, that does not form carbon or gums to obtain the best signal to noise ratio. Samples above I mg/L require proportionally lower injection rates or span adjustment. A sharp fall in response at high sulfur levels indicates color saturation o f the tape, which can be prevented by slower injection rates. 11. Calculations and Report 1 1.1 Calculate the concentration of the sulfur in the sample as follows: S, mg/L = C ~ x (R, - R b ) / ( R ~ o - Rb)

(3)

where: Cstd = concentration of sulfur in the standard, rag/L, Rb = response for blank run using no sample or for solvent known to be sulfur-free, R, = response for unknown sample, and R,td = response for standard reference material. I 1.2 Report mass of parts per million of sulfur as follows: S, ppm = (mg/L)/(density) ffi mg/kg (4) since density of sample is in grams per cubic centimetres. 12. Precision and Bias

12.1 The precision of this test method as obtained by statistical analysis of interlaboratory test results is as follows: 12. I. 1 Repeatability----The difference between successive test results obtained by the same operator with the same

12.2 Bias--The bias of this test method cannot be determined since an appropriate standard reference material containing trace sulfur levels in petroleum products is not available. 13. Keywords 13.1 rateometric colorimetry; sulfur

TABLE 1 Repeatabilityand Reproducibility Average value mg/kg of two

Repeatability,

Reprodudblllty,

resats (x)

mo/kg

n~/kg

0.02 0.10 0.50 1.50 2.50 10.00

0.02 0.05 0.11 0.16 0.25 0.50

0.04 0.08 0.18 0.26 0.41 0.82

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned In this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of Infringement of such rights, are entirely their own responsibility. This standard Is subject to revision at any time by the responsible technical committee and must be reviewed every five years and # not revised, althar reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend, ff you feel that your comments have not received s fair hearing you should make your views known to the ASTM Committee on Standards, 100 Barr Harbor Drive, West Conshohockan, PA 19428.

620

Designation: D 4052 - 96

An Arnedcan National Standard

Designation: 365/84(86) ~ . i.i I ~ n H I M

Standard Test Method for Density and Relative Density of Liquids by Digital Density Meter I This standard is issued under the fixed designation D 4052; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epdlon (~) indicates an editorial change since the last revision or reapproval.

This method was adopted as a joint ASTM-IP standard in 1984.

1. Scope 1.1 This test method covers the determination of the density or relative density of petroleum distillates and viscous oils that can be handled in a normal fashion as liquids at test temperatures between 15 and 35°C. Its application is restricted to liquids with vapor pressures below 600 mm Hg (80 kPa) and viscosities below about 15 000 cSt (mm2/s) at the temperature of test. 1.2 This test method should not be applied to samples so dark in color that the absence of air bubbles in the sample cell cannot be established with certainty. For the determination of density in crude oil samples use Test Method D 5002. 1.3 The accepted units of measure for density are grams per miUilitre or kilograms per cubic metre. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements, see Notes 1 and 2. 2. Referenced Document

3.1.1 density--mass per unit volume at a specified temperature. 3.1.2 relative density.--the ratio of the density of a material at a stated temperature to the density of water at a stated temperature. 4. Summary of Test Method 4.1 A small volume (approximately 0.7 mL) of liquid sample is introduced into an oscillating sample tube and the change in oscillating frequency caused by the change in the mass of the tube is used in conjunction with calibration data to determine the density of the sample. 5. Significance and Use 5.1 Density is a fundamental physical property that can be used in conjunction with other properties to characterize both the light and heavy fractions of petroleum and petroleum products. 5.2 Determination of the density or relative density of petroleum and its products is necessary for the conversion of measured volumes to volumes at the standard temperature of 150C.

2.1 A S T M Standard:

6. Apparatus 6.1 Digital Density AnalyzernA digital analyzer consisting of a U-shaped, oscillating sample tube and a system for electronic excitation, frequency counting, and display. The analyzer must accommodate the accurate measurement of the sample temperature during measurement or must control the sample temperature as described in 6.2. The instrument shall be capable of meeting the precision requirements described in this test method. 6.2 Circulating Constant-Temperature Bath, (optional) capable of maintaining the temperature of the circulating liquid constant to +0.05"C in the desired range. Temperature control can be maintained as part of the density analyzer instrument package. 6.3 Syringes, at least 2 mL in volume with a tip or an adapter tip that will fit the opening of the oscillating tube. 6.4 Flow-Through or Pressure Adapter, for use as an alternative means of introducing the sample into the density analyzer either by a pump or by vacuum. 6.5 Thermometer, calibrated and graduated to 0. I'C, and a thermometer holder that can be attached to the instrument for setting and observing the test temperature. In calibrating

D 1193 Specification for Reagent Water2 D 1250 Guide for Petroleum Measurement Tables3 D4057 Practice for Manual Sampling of Petroleum and Petroleum Products4 D 4177 Practice for Automatic Sampling of Petroleum and Petroleum Products4 D4377 Test Method for Water in Crude Oils by Potentiometric Karl Fischer Titration4 D 5002 Test Method for Density and Relative Density of Crude Oils by Digital Density Analyzer5 3. Terminology 3.1 Definitions: This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.04 on Hydrocarbon Analysis. Current edition approved Apr. 10, 1996. Published June 1996. Originally published as D 4052 - 81. Last previous edition D 4052 - 95. 2 Annual Book of A S T M Standards, Vol 1 !.01. 3 Annual Book of A S T M Standards, Vol 05.01. 4 Annual Book of A S T M Standards, Vol 05.02. Annual Book of A S T M Standards, Vol 05.03.

621

([~ D 4052 bath following the manufacturer's instructions. Adjust the bath or internal temperature control so that the desired test temperature is established and maintained in the sample compartment of the analyzer. Calibrate the instrument at the same temperature at which the density of the sample is to be measured. NOTE 3: Caution--Precise setting and control of the test temperature in the sample tube is extremely important. An error of 0. I'C can result in a change in density of one in the fourth decimal.

the thermometer, the ice point and bore connections should be estimated to the nearest 0.05"C. 7. Reagents and Materials 7.1 Purity of Reagents--Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, where such specifications are available. 6 Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination. 7.2 Purity of Water--Unless otherwise indicated, references to water shall be understood to mean reagent water as defined by Type II of Specification D 1193. 7.3 Water, redistilled, freshly boiled and cooled reagent water for use as a primary calibration standard. 7.4 Petroleum Naphtha, 7 for flushing viscous petroleum samples from the sample tube. NOTS l--Extremely flammable. 7.5 Acetone, for flushing and drying the sample tube. NOT~ 2: Warning--Extremely flammable. 7.6 Dry Air--for blowing the oscillator tube. 8. Sampling, Test Specimens, and Test Units 8.1 Sampling is defined as all the steps required to obtain an aliquot of the contents of any pipe, tank, or other system, and to place the sample into the laboratory test container. The laboratory test container and sample volume shall be of sufficient capacity to mix the sample and obtain a homogeneous sample for analysis. 8.2 Laboratory Sample--Use only representative samples obtained as specified in Practices D 4057 or D 4177 for this test method. 8.3 Test Specirnen--A portion or volume of sample obtained from the laboratory sample and delivered to the density analyzer sample tube. The test specimen is obtained as follows: 8.3.1 Mix the sample if required to homogenize. The mixing may be accomplished as described in PracticeD 4177 (Section I I) or Test Method D 4377 (A.I). Mixing at room temperature in an open container can result in the loss of volatilematerial,so mixing in closed, pressurized containers or at sub-ambient temperatures is recommended. 8.3.2 Draw the test specimen from a properly mixed laboratory sample using an appropriate syringe.Alternatively,if the proper density analyzer attachments and connecting tubes are used then the test specimen can be delivered directlyto the analyzer'ssample tube from the mixing container, 9. Preparation of Apparatus 9.1 Set up the density analyzer and constant temperature Reagent Chemicals. American Chemical Society Spec~cations, American Cl~mic~ Society, Washington, De. For suggesliom on the testing of reagen~ not listod by tim Ammiean Chemical So~e~J, ~ Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dor~t, O.K., and the United States Pharmacopeia and National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Roekville, MD. ":Suitable solvent naphthas are marketed under various dedgnafiom such as "Petroleum Ether," "Ligtoine," or "Precipitation Naphtha."

622

10. Calibration of Apparatus 10.1 Calibrate the instrument when first set up and whenever the test temperature is changed. Thereafter, conduct calibration checks at weekly intervals during routine operation. 10.2 Initial calibration, or calibration after a change in test temperature, necessitates calculation of the values of the constants A and B from the periods of oscillation (T) observed when the sample cell contains air and redistilled, freshly boiled and cooled reagent water. Other calibrating materials such as n-nonane, n-tridecane, cyclohexane, and n-hexadecane (for high temperature applications) can also be used as appropriate. 10.2.1 While monitoring the oscillator period, T, flush the sample tube with petroleum naphtha, followed with an acetone flush and dry with dry air. Contaminated or humid air can affect the calibration. When these conditions exist in the laboratory, pass the air used for calibration through a suitable purification and drying train. In addition, the inlet and outlet ports for the U-tube must be plugged during measurement of the calibration air to prevent ingress of moist air. 10.2.2 Allow the dry air in the U-tube to come to thermal equilibrium with the test temperature and record the T-value for air. 10.2.3 Introduce a small volume (about 0.7 mL) of redistilled, freshly boiled and cooled reagent water into the sample tube from the bottom opening using a suitable syringe. The test portion must be homogeneous and free of even the smallest air or gas bubbles. The sample tube does not have to be completely full as long as the liquid meniscus is beyond the suspension point. Allow the display to reach a steady reading and record the T-value for water. 10.2.4 Calculate the density of air at the temperature of test using the following equation: d,, g/mE = 0.001293[273.15/T][P/760] (1) where: T = temperature, K, and P ffi barometric pressure, torr. 10.2.5 Determine the density of water at the temperature of test by reference to Table 1. 10.2.6 Using the observed T-values and the reference values for water and air, calculate the values of the Constants A and B using the following equations: A = [T~ - Ta2l/tdw - dol (2) B == Ta 2 - (A × do) (3) where: Tw = observed period of oscillation for cell containing water, T. = observed period of oscillation for cell containing air, dw = density of water at test temperature, and

~)

D 4052

da = density of air at test temperature. Alternatively, use the T and d values for the other reference liquid if one is used. 10.2.7 If the instrument is equipped to calculate density from the constants A and B and the observed T-value from the sample, then enter the constants in the instrument memory in accordance with the manufacturer's instructions. 10.2.8 Check the calibration and adjust if needed by performing the routine calibration check described in 10.3. 10.2.9 To calibrate the instrument to display relative density, that is, the density of the sample at a given temperature referred to the density of water at the same temperature, follow sections 10.2.1 through 10.2.7, but substitute 1.000 for d~ in performing the calculations described in 10.2.6. 10.3 Weekly calibration adjustments to constants A and B can be made if required, without repeating the calculation procedure. NOTE 4---The need for a change in calibration is generally attributable to deposits in the sample tube that are not removed by the routine

flushingprocedure. Althoughthis conditioncan be compensatedfor by adjusting A and B, it is good practice to clean the tube with warm chromic acid solution (Warning---Causes severe burns. A l'CCogniT~J carcinogen.) whenever a major adjustment is required. Chromic acid solution is the most effective cleaning agent; however, surfactant cleaning fluidshave also been used successfully. 10.3.1 Flush and dry the sample tube as described in 9.2.1 and allow the display to reach a steady reading. If the display does not exhibit the correct density for air at the temperature of test, repeat the cleaning procedure or adjust the value of constant B commencing with the last decimal place until the correct density is displayed. 10.3.2 If adjustment to constant B was necessary in 10.3.1 then continue the recalibration by introducing redistilled, freshly boiled and cooled reagent water into the sample tube as described in 10.2.3 and allow the display to reach a steady reading. If the instrument has been calibrated to display the density, adjust the reading to the correct value for water at the test temperature (Table 1) by changing the value of constant A, commencing with the last decimal place. If the instrument has been calibrated to display the relative density, adjust the reading to the value 1.0000.

and water. The settingchosen wouldthen be dependentupon whetherit was approached from a higher or lower value. The setting selected by this method could have the effect of altering the fourth place of the reading obtainedfor a sample. 10.4 Some analyzer models are designed to display the measured period of oscillation only (T-values) and their calibration requires the determination of an instrument constant K, which must be used to calculate the density or relative density from the observed data. 10.4.1 Flush and dry the sample tube as described in 10.2.1 and allow the display to reach a steady reading. Record the T-value for air. 10.4.2 Introduce redistilled, freshly boiled and cooled reagent water into the sample tube as described in 10.2.3, allow the display to reach a steady reading and record the T-value for water. 10.4.3 Using the observed T-values and the reference values for water and air (10.2.4 and 10.2.5), calculate the instrument constant K using the following equations: For density: KI = [ # w - aa]/[ r 2 - Ta2]

For relative density: K2 = [1.0000 - aa]/[T 2 - Ta2]

11. Procedure 11.1 Introduce a small amount (about 0.7 mL) of sample into the dean, dry sample tube of the instrument using a suitable syringe. 11.2 The sample can also be introduced by siphoning. Plug the external TFE-fluorocarbon capillary tube into the lower entry port of the sample tube. Immerse the other end of the capillary in the sample and apply suction to the upper entry port using a syringe or vacuum line until the sample tube is properly filled. 11.3 Turn on the illumination fight and examine the sample tube carefully. Make sure that no bubbles are trapped in the tube, and that it is filled to just beyond the suspension point on the right-hand side. The sample must be homogeneous and free of even the smallest bubbles.

TABLE 1 Densityof WaterA

NOTE 6--If the sample is too dark in color to determine the absence

of bubbles with certainty,the density cannot be measured within the stated precision limitsof Section 14. 11.4 Turn the illumination light off immediately after sample introduction, because the heat generated can affect the measurement temperature. 11.5 After the instrument displays a steady reading to four significant figures for density and five for T-values, indicating that temperature equilibrium has been reached, record the density or T-value.

Temperature, Density, Temperature, Danslty, Temperature, Density, *C g/mL *C g/mL *C g/mL 0.999840 0.999964 0.999972 0.999964 0.999699 0.999099 0.999012 0.998943 0.998774 0.996595 0.996404 0.998203

21.0 22.0 23.0 24.0 25.0 26.0 27.0 28.0 29.0 30.0 35.0 37.78

0.997991 0.997769 0.997537 0.997295 0.997043 0.996782 0.996511 0.996231 0.995943 0.995645 0.994029 0.993042

(5)

where: Tw = observed period of oscillation for cell containing water, T a = observed period of oscillation for cell containing air, dw = density of water at test temperature, and d,, = density of air at test temperature.

NOTE 5--In applying this weekly calibration procedure, it can be found that more than one value each for A and B, differing in the fourth decimal place, will yield the correct density reading for the density of air

0.0 3.0 4.0 5.0 10.0 15.0 15.56 16.0 17.0 18.0 19.0 20.0

(4)

40.0 45.0 50.0 55.0 60.0 65.0 70.0 75.0 80.0 85.0 90.0 100

0.992212 0.990208 0.988030 0.985688 0.983191 0.980546 0.977759 0.974837 0.971785 0.968606 0.965305 0.958345

12. Calculation 12.1 Calculating D e n s i t y A n a l y z e r s - - T h e recorded value is the final result, expressed either as density in g/mL, kg/m 3 or as relative density. Note that kg/m 3 -- 1000 × g/mL.

A D(msities conforming to the InternationalTemperature Scale 1990 (ITS 90) were extracted from Appendix G, Standard Methods for Analysis of Petroleum and Related Products 1991, Institute of Petroleum, London.

623

~) D 4052 examination of intedaboratory test results at test temperatures of 15 and 20°C is as follows: 14.1.1 Repeatability--The difference between successive test results obtained by the same operator with the same apparatus under constant operating conditions on identical test material, would in the long run, in the normal and correct operation of the test method, exceed the following value only in one case in twenty:

12.2 Noncalculating Density A n a l y z e r s - - U s i n g the observed T-value for the sample and the T-value for water and appropriate instrument constants determined in 10.4.3, calculate the density or relative density using Eqs 6 and 7. Carry out all calculations to six significant figures and round the final results to four. For density: density, g/rnL (kg/dm3) at t = dw + KI(Ts 2 - Tw2) (6) For relative density: relative density, t/t = 1 + K2(Ts2 - T2) (7) where: Tw = observed period of oscillation for cell containing water, Ts = observed period of oscillation for cell containing sample, dw = density of water at test temperature, K m = instrument constant for density, /(2 = instrument constant for relative density, and t = temperature of test, "C. 12.3 If it is necessary to convert a result obtained using the density meter to a density or relative density at another temperature, Guide D 1250 can be used only if the glass expansion factor has been excluded.

Range 0.68--0.97 g/mL

Repeatability 0.0001

14.1.2 Reproducibility--The difference between two single and independent results, obtained by different operators working in different laboratories on identical test material, would in the long run, in the normal and correct operation of the test method, exceed the following values only in one case in twenty: Range 0.68-0.97 g/mL

Reproducibility 0.0005

14.2 B i a s - - A f t e r suggestions of its existence from literature9, a study has been performed which has confirmed the presence of a bias between known density values for reference materials and from values determined according to this test method on the same reference materials. The matrix for this bias study comprised 15 participants, each analyzing four reference oils with certified density values, established by the Netherlands Meet Instituut (NMI), by pyknometry, covering densities in the range of 747 to 927 kg/m 3 at 20"C, with viscosities between 1 and 5 000 mPa.s (also at 20*C). This study is documented in ASTM Research Report RRD02-1387. Method users should, therefore, be aware that results obtained by this test method can be biased by as much as 0.6 kg/m 3 (0.0006 g/mL).

13. Report 13.1 In reporting density, give the test temperature and the units (for example: density at 200C = 0.8765 g/mL or 876.5 kg/m3). 13.2 In reporting relative density, give both the test temperature and the reference temperature, but no units (for example: relative density, 20/20°C = 0.xxxx). 13.3 Report the final result to the fourth decimal place.

15. Keywords 14. Precision and Biasa 14. l The precision ofthe method as obtained by statistical

15.1 density; digital density analyzer; petroleum distillates; petroleum products; relative density

s Statistical data b available as a research report from ASTM Headquarters. Request RR:D02-1387.

Petroleum Review, November 1992, pp. 544--549.

9 Fitzgerald, H. and D., "An Assessment of Laboratory Density Meters, ~

The American Society for Testing and Materials talcesno position respecting the validity of any patent rights asserted in connection with any item mentioned In this standard. Users Of this standard are expressly advised that determination Of the validity Of any such patent right& and the risk of Infringement of such rights, are entirely their own respon,slbllity. This atanbe~l is subject to revision at any time by the responsive technical committee and must be reviewed every five years and if not revised, enhar respproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at s meeting of the responsive technical committee, which you may attend. If you feel that your comments have not received • fair hearing you should make your views known to the ASTM Committee on Standards, 100 Barr Harbor Drive, West Conshohocken, PA 19428.

624

Designation: D 4053 - 95

An Amencan National Standard

Standard Test Method for B e n z e n e in Motor and Aviation Gasoline by Infrared Spectroscopy 1 This standard is issued under the fixed designation D 4053; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (~) indicates an editorial change since the last revision or reapproval.

T = P/Po

1. Scope 1.1 This test method covers the determination of the percent benzene in full-range gasoline. It is applicable to concentrations from 0.1% to 5 volume %. 1.2 The values in SI units are regarded as the standard. 1.3 This test method has not been validated for gasolines containing oxygenates. 1.4 This standard does not purport to address all of the

where: P = the radiant power passing through the sample, and P,, = the radiant power incident upon the sample.

4. Summary of Test Method 4.1 A sample of gasoline is examined by infrared spectroscopy and, following a correction for interference, compared with calibration blends of known benzene concentration. From this comparison the amount of benzene in the gasoline is determined.

safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements, see Section 8 and 9.1.

5. Significance and Use 5.1 Benzene is classed as a toxic material. A knowledge of the concentration of this compound may be an aid in evaluating the possible health hazard to persons handling and using the gasoline. This test method is not intended to evaluate such hazards.

2. Referenced Documents

2.1 ASTM Standards: D4057 Practice for Manual Sampling of Petroleum and Petroleum Products 2 E 131 Terminology Relating to Molecular Spectroscopy3 E 275 Practice for Describing and Measuring Performance of Ultraviolet, Visible, and Near Infrared Spectrophotometers 3

6. Interferences 6.1 Toluene and heavier aromatic compounds have some interference in this test method. In order to minimize the effect of such interference, this method includes a procedure that corrects for the error caused by the presence of toluene. Error due to other sources of interference may be partially compensated for by calibrating with gasoline stocks containing little or no benzene but which otherwise are similar in aromatic content to the samples to be analyzed.

3. Terminology

3.1 Definitions: 3.1.1 Definitions of terms and symbols relating to absorption spectroscopy in this test method shall conform to Terminology E 13 I. Terms of particular significance are the following: 3.1. I. l absorbance, A, n - - t h e molecular property of a substance that determines its ability to take up radiant power, expressed by: A = ioglo(l/T) = -log10 T

(2)

7. Apparatus 7.1 Absorption Cell, sealed. Windows of potassium bromide or other material having sufficient transmittance out to 440 cm -~ (22.73 Ixm), in a cell having TIE-fluorocarbon plugs and nominal path length of 0.025 mm known to three significant numbers. 7.2 Clear Reference Block--A block made from the same material as cell windows for use in the reference beam path of a double-beam spectrometer. 7.3 Infrared Spectrometer, double-beam or single-beam, suitable for recording accurate measurements between 690 cm -I (14.49 ~tm) and 440 cm -I (22.73 p.m). Refer to Practice E 275.

(l)

where T = the transmittance as defined in 3. I. 1.4. 3.1.1.2 radiant energy, n--energy transmitted as electromagnetic waves. 3. I. 1.3 radiant power, P, n - - t h e rate at which energy is transported in a beam of radiant energy. 3. I. 1.4 transmittance, T, n - - t h e molecular property of a substance that determines its transportability of radiant power, expressed by:

NOTE l - - A b s o r b a n c e s for the bands specified in this method are

This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee I)02.04 on Hydrocarbon Analysis. Current edition approved Sept. 10, 1995. Published November 1995. Originally published as D 4053 - 81. Last previous edition D 4053 - 91. 2 Annual Book of ASTM Standards, Vol 05.02. Annual Book of ASTM Standards, Vol 03.06.

expected to fall within the linear operating range of modern spectrometers for the concentration range as defined.

8. Reagents 8.1 Benzene, spectroscopic or research grade. (Warning-625

~

D 4053

Poison, carcinogen, harmful, or fatal if swallowed. Extremely flammable.) 8.2 Toluene, spectroscopic or research grade. (Warning-Flammable, harmful if inhaled.) 8.3 Isooctane (2,2,4-trimethylpentane) or n-Heptane, spectroscopic or research grade. (Warning--Isooctane and nHeptane are extremely flammable, harmful if inhaled.) 9. Sampling 9.1 Follow the procedures and precautions contained in Practice D 4057. (Warning~Gasolines are extremely flammable, harmful if inhaled.) 9.2 Cool the sample container and contents to 0 to 4"C before opening the container and transferring material to other containers. 10. Calibration and Standardization 10.1 Reference StandardsmPrepare standard blends of benzene using fresh, full-range gasoline of low benzene content (less than 1 volume percent) as the solvent. Measure and dilute all components at ambient temperature. Accurately pipet the required volume of benzene into 100-mL volumetric flasks partially filled with the gasoline. Dilute to volume with additional gasoline. Prepare the blends in I volume % increments. 10.2 Toluene StandardmPrepare a blend of toluene in either isooctane or n-heptane as the solvent. Measure and dilute all components at ambient temperature. Accurately pipet 2 mL of toluene into a 10-mL volumetric flask partially filled with either isooctane or n-heptane. Dilute to volume with the chosen solvent. 10.3 Calibration: 10.3.1 Following the steps of Section 11, Procedure, for each of the standard blends and the gasoline base stock, determine three absorbance values: (1) at the point of maximum absorbance near 673 cm-i (14.86 ~m), designated the benzene band; (2) at the point of maximum absorbance near 460 cm-t (21.74 ttm), designated the toluene band; and (3) at 500 cm -l (20.00 ~tm), designated the baseline position. 10.3.2 Following the steps of Section 11, Procedure, for the toluene standard, determine the absorbances at the locations described in 10.3.1 for the benzene band, the toluene band, and the baseline position. Subtract the baseline position value at about 500 cm -j from those found for benzene at about 673 cm -~ and toluene at about 460 cm -~ in order to obtain the net absorbance for each. Take the ratio of the benzene band net absorbance to the toluene band net absorbance to obtain the toluene correction factor. 10.3.3 For the gasoline base stock and each blend examined in 10.3. I, obtain the net absorbances at the benzene and the toluene bands by subtracting the baseline position value from the absorbances found for the band maxima. Continuing, for each liquid, multiply the toluene band net absorbance by the toluene correction factor found in 10.3.2 and subtract this value from the benzene band net absorbance in order to obtain the corrected net absorbance for the benzene band. 10.3.4 Construct a curve by plotting the benzene band corrected net absorbance for each calibration liquid, as found

626

in 10.3.3, divided by the cell path length in millimetres, versus the volume percent of added benzene for each. 10.3.5 Extrapolate the curve to zero absorbance. The absolute value of the intercept is the concentration of benzene in the gasoline used as the solvent. 10.3.6 Construct a standard reference curve by replotting the baseline absorbances per millimetre thickness, corrected in 10.3.5, against total concentration of benzene in percent by volume so that the curve passes through the origin. NOT~ 2--A linear equation can be used instead of the plot. 11. Procedure l I. 1 Clean the cell with isooctane or similar solvent and dry by means of a source of vacuum. 11.2 Fill the absorption cell with the gasoline to be tested. Both cell and sample should be at ambient temperature during this operation. If moisture condensation is a problem, blanket the cell with a dry, inert atmosphere. Use care to avoid formation of air pockets in the cell and scan immediately to prevent bubbles from forming. Observe the cell during the scan period to check for bubble formation. l l.3 Scan the infrared spectrum from 690 cm -I (14.99 lam) to 440 cm -I (22.73 lam) versus a clear reference block in the reference beam (for double-beam operation); follow the directions of the manufacturer for quantitative analysis. I 1.4 Determine the corrected net absorbance of the benzene band as described in 10.3.3. l l.5 Divide the benzene band corrected net absorbance, as found in I 1.4, by the cell path length in miilimetres. 12. Calculation 12.1 Calculate the benzene content of the gasoline in liquid volume percent by entering the calibration curve of 10.3.6 or the equation in Note 2 with the value of the benzene band found in 11.5. 12.2 If the results are desired on a weight basis, convert to mass percent, as follows: B = V x 0.8844/R (3) where: B = mass percent of benzene, V = volume percent of benzene, and R = relative density of sample, 15/15"C. 13. Report 13.1 Report numerical results to the nearest 0.1 volume %. 14. Precision and Bias 14.1 The precision of the method as obtained by statistical examination of interlaboratory results is as follows: 14.1.1 Repeatability--The difference between successive test results, obtained by the same operator with the same apparatus under constant operating conditions on identical test materials, would in the long run, in normal and correct operation of the test method, exceed 0.08 volume % only in one case in twenty. 14.1.2 ReproducibilitymThe difference between two single and independent results, obtained by different operatots working in different laboratories on identical test material, would in the long run, in the normal and correct

(1~ D 4053 15. Keywords

operation of the test method exceed O. 18 volume % only in one case in twenty. 14.2 Bias--There are no interlaboratory test data to establish a statistical statement on bias.

15.1 aviation gasoline; benzene; infrared spectroscopy; motor gasoline

The American Society for Testing and Materials takes no position respecting the vah'dity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and ff not revised, either reepproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St,, Philadelphia, PA 19103.

627

Designation: D 4057 - 95 (1

IPW II. I , , I I H . I ~. I*It m . l U M

An American Naeonal Standard

Designation: MPMS (Chapter 8.1)

Standard Practice for Manual Sampling of Petroleum and Petroleum Products I This standard is issued under the fixed designation D 4057; the number immediately following the de~im~a~ionindicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (d indicates an editorial change since the last revision or reapproval. This test method has been approved by the sponsoring committees and accepted by the Cooperating Societies in accordance with established procedures. This method was issued as a joint A~FM-AP1 standard in 1981. et NOTEmEditorial correctious were made tu 8.3 in November 1997.

1. Scope

1.1 This practice covers procedures for manually obtaining representative samples of petroleum products of a liquid, semi-liquid, or solid state whose vapor pressure at ambient conditions is below 101 kPa (14.7 psia). If sampling is for the precise determination of volatility, use Practice D 5842 in conjunction with this practice. For sample mixing and handling of samples, refer to Practice D 5854. The practice does not cover sampling of electrical insulating oils and hydraulic fluids. A summary of the manual sampling procedures and their applications is presented in Table 1. NoT~ l--The procedures described in this method may also be applicable in sampl/ng most noncorrosiveliquid industrial chemicals, provided that all safety precautions specific to these chemicals are strictlyfollowed. NOtE 2--The procedure for sampling liquified petroleum gases is described in Practice D 1265; the procedure for sampling fluid power hydraulicfluidsis covered in ANSI B93.19 and B93.44; the procedure for samplinginsulatingotis is describedin Test Method D 923; and the procedure for samplingnatural gas is describedin Test Method D 1145. NOtE 3--The procedure for special fuel samples for trace metal analysisis describedin an appendixto SpecificationD 2880. 2. Referenced Documents 2.1 ASTM Standards: D 86 Test Method for Distillation of Petroleum Products2 D 217 Test Methods for Cone Penetration of Lubricating Grease 2 D 244 Test Methods for Emulsified Asphalts3 D 268 Guide for Sampling and Testing Volatile Solvents and Chemical Intermediates for Use in Paint and Related Coatings and Materials4 D323 Test Method for Vapor Pressure of Petroleum Products (Reid Method)2 1 This practice is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee 1302.02 on Static Petroleum Measurement (Joint ASTM-API). Current edition approved Nov. 10, 1995. Published January 1996. Originally published as D 4057 - 81. Last previous edition D 4057 - 88. 2 Annual Book of A S T M Standards, Vol 05.01. 3 Annual Book of A S T M Standards, Vol 04.03. 4 Annual Book of A S T M Standards, Vol 06.04.

D 346 Practice for Collection and Preparation of Coke Samples for Laboratory Analysiss D 525 Test Method for Oxidation Stability of Gasoline (Induction Period Method)2 D 873 Test Method for Oxidation Stability of Aviation Fuels (Potential Residue MethOd)2 D923 Test Method for Sampling Electrical Insulating Liquids6 D 977 Specification for Emulsified Asphalt3 D 1145 Test Method for Sampling Natural Cras5 D 1265 Practice for Sampling Liquefied Petroleum (LP) Gases--Manual MethOd2 D 1856 Test Method for Recovery of Asphalt from Solution by Abson Method 3 D 2172 Test Methods for Quantitative Extraction of Bitumen from Bituminous Paving Mixtures 3 D 2880 Specificationfor Gas Turbine Fuel Oils7 D 4177 Practicefor Automatic Sampling of Petroleum and Petroleum Products v D 4306 Practice for Aviation Fuel Sample Containers for Tests Affected by Trace Contamination 7 D5842 Practice for Mixing and Handling of Liquid Samples of Petroleum and Petroleum Products D 5854 Practice for Sampling and Handling of Fuels for VolatilityMeasurements 2.2 American National Standards: s B93.19 Standard Method for Extraction Fluid Samples from the Lines of an Operating Hydraulic Fluid Power System (for Particulate Contamination Analysis) B93.44 Method for Extracting Fluid Samples from the Reservoir of an Operating Hydraulic Fluid Power System 2.3 API Manual of Petroleum Measurement Standards: 9 Chapter 8.2 Automatic Sampling of Petroleum and Petroleum Products s Annual Book of A S T M Standards, Vo105.05. 6 Annual Book of A S T M Standards, Vol 10.03. 7 Annual Book of A S T M Standards, Vo105.02. s Available from American National Standards Institute, 11 W. 42rid St., 13th Floor, New York, NY 10036. 9 Available from American Petroleum Institute, 1220 L St., NW, Washington, DC 20O05.

628

~ TABLE 1

D 4057

Typical Sampling Procedures and Applicability

ApplicaUon

Type of Container

Liquids of more than (13.8 kPa) and not more than 101 kPa (14.7 psia) RVP

storage tanks, ship and barge tanks, tank cars, tank trucks

Liquids of 101 kPa (14.7 psia) RVP or less Bottom sampling of liquids of 13.8 kPa (2 psia) RVP or less Liquids of 101 kPa (14.7 psle) RVP or less Liquids of 13.8 kPe (2 psla) RVP or less Liquids of 13.8 kPe (2 psle) RVP or less Liquids of 13.8 kPa (2 psia) RVP or less Bottom or thief sampling of liquids of 13.8 kPa (2 psle) RVP or less Liquids and semMiquids of 13.8 kPe (2 psla) RVP or less

storage tanks with taps storage tanks with taps pipes or lines storage tanks, ships, barges free or open-dischergestreams drums, barrels, cans tank cars, storage tanks free or open-dischargestreams; open tanks or kettles with open heads; tank cars, tank trucks, drums storage tanks, ship and barge, tanks, tank cars, tank trucks,

Crude petroleum

p~p~ines

P~ure

~t~e sainting thief sampling tap ssmpllng samp,ng ~p~e ~ n g botUessrn~ng dipper sampling tube sampllng

san~g dipper sampling automaUc sarnpllng thief ssmpllng

Industrial aromatic hydrocarbons Waxes, solids b~m~ns, other soft solids Petroleum coke; lumpy solids Greases, soft waxes, asphalts Asphaltic materials Emulsified asphalts

storage tanks, ship and barge tanks barrels, cases, bags, cakes freight cars, conveyors, bags, barrels, boxes kettles, drums, cans, tubes storage tanks, tank cars, lines, packages storage tanks, tank cars, lines, packages

Chapter 8.3 Standard Practice for Mixing and Handling of Liquid Samples of Petroleum and Petroleum Products Chapter 8.4 Standard Practice for the Sampling and Handling of Fuels for Volatility Measurements Chapter 9.3 Thermohydrometer Test Method for Density and API Gravity of Crude Petroleum and Liquid Petroleum Products Chapter 17.1 Guidelines for Marine Cargo Inspection Chapter 17.2 Measurement of Cargoes Aboard Marine Tank Vessels Chapter 18.1 Measurement Procedures for Crude Oil Gathered from Small Tanks By Truck Chapter 10, various sections, Sediment and Water Determination

borne ssmpl~g tap s~npling bottle sampling boring sampling grab sampling greasesampling

regulatory agencies require 15 cm (6 in.)) below the bottom of the tank outlet. (a) Discussion--This term is normally associated with small (159 m a or 1000 Bbls or less) tanks, commonly referred to as lease tanks. 3.1.1.6 composite sample--a blend of spot samples mixed in proportion to the volumes of material from which the spot samples were obtained. 3.1.1.7 core sample--a sample of uniform cross sectional area taken at a given height in a tank. 3.1.1.8 dipper sample--a sample obtained by placing a dipper or other collecting vessel in the path of a free-flowing stream to collect a definite volume from the full cross section of the stream at regular time intervals for a constant time rate of flow or at time intervals varied in proportion to the flow rate. 3.1.1.9 drain sample--a sample obtained from the water draw-off valve on a storage tank. (a) Discussion--Occasionally, a drain sample may be the same as a bottom sample (for example, in the case of a tank car). 3.1.1.10 floating roof samplema spot sample taken just below the surface to determine the density of the liquid on which the roof is floating. 3.1.1.11 flow proportional sample--a sample taken from a pipe such that the rate of sampling is proportional throughout the sampling period to the flow rate of the fluid in the pipe. 3.1.1.12 grab sample--a sample obtained by collecting equal quantities from parts or packages of a shipment of loose solids such that the sample is representative of the entire shipment. 3.1.1.13 grease samplema sample obtained by scooping or dipping a quantity of soft or semi-liquid material conrained from a package in a representative manner. 3.1.1.14 lower sample~a spot sample of liquid from the middle of the lower one-third of the tank's content (a distance of five-sixths of the depth liquid below the liquid's surface). See Fig. 1.

3. Terminology 3.1 Description of Terms Specific to This Standard: 3.1.1 Samples: 3.1.1.1 all-levels sample--a sample obtained by submerging a stoppered beaker or bottle to a point as near as possible to the draw-off level, then opening the sampler and raising it at a rate such that it is approximately three-fourths full as it emerges from the liquid. 3.1.1.2 boring sample--a sample of the material conrained in a barrel, case, bag, or cake that is obtained from the chips created by boring holes into the material with a ship auger. 3.1.1.3 bottom sample--a spot sample collected from the material at the bottom of the tank, container, or line at its lowest point. (a) Discussion--In practice, the term bottom sample has a variety of meanings. As a result, it is recommended that the exact sampling location (for example, 15 cm from the bottom) should be specified when using this term. 3.1.1.4 bottom water sample--a spot sample of free water taken from beneath the petroleum contained in a ship or barge compartment or a storage tank. 3.1.1.5 clearance samplema spot sample taken with the inlet opening of the sampling apparatus 10 cm (4 in.) (some 629

~

D 4057

Hatch

,[--15 cm (6") I

~ Tank contents

Outlet

Top sample Upper sample

Upper third

X

Middle sample

Middle third

×

Lower sample /~-- Outlet sample

Lower third

Bottom sample

NOTE 1--The location shown for the outlet sample applies only to tanks with side outleta, it doas not apply when the outlet comes from the floor of the tank or turns down into a sump. Bottom sample location must be specified. NOTE 2 ~ should be obtained from within solid stand pipes as the materials normally not representative of the material in the tank at that point. FIG. 1 Spot Sampling Locations

3.1.1.15 middle sample--a spot sample taken from the middle tank's contents (a distance of one-half of the depth of liquid below the liquid's surface). See Fig. 1. 3.1.1.16 multiple tank composite sample--a mixture of individual samples or composites of samples that have been obtained from several tanks or ship/barge compartments containing the same grade of material. (a) Discussion--The mixture is blended in proportion to the volume of material contained in the respective tanks or compartments. 3.1.1.17 outlet sample--a spot sample taken with the inlet opening of the sampling apparatus at the level of the bottom of the tank outlet (fixed or floating). See Fig. 1. 3.1.1.18 representative sample--a portion extracted from the total volume that contains the constituents in the same proportions that are present in that total volume. 3. I. 1.19 running sample--a sample obtained by lowering a breaker or bottle to the level of the bottom of the outer connection or swing line and returning it to the top of the oil at a uniform rate such that the beaker or bottle is about three-fourths full when withdrawn from the oil. 3. I. 1.20 sample--a portion extracted from a total volume that may or may not contain the constituents in the same proportions that are present in that total volume. 3.1.1.21 sampling--all the steps required to obtain a sample that is representative of the contents of any pipe, tank, or other vessel and to place that sample in a container from which a representative test specimen can be taken for analysis. 3.1.1.22 spot sample--a sample taken at a specific location in a tank or from a flowing stream in a pipe at a specific time. 3.1.1.23 su(face sample--a spot sample skimmed from the surface of a liquid in a tank. 3.1.1,24 tank composite sample--a blend created from the upper, middle, and lower samples from a single tank. (a) Discussion--For a tank of uniform cross section, such as an upright cylindrical tank, the blend consists of equal parts of the three samples. For a horizontal cylindrical tank, 630

the blend consists of three samples in the proportions shown in Table 2. 3.1.1.25 tap sample--a spot sample taken from a sample tap on the side of a tank. It may also be referred to as a tank-side sample. 3.1.1.26 top sample--a spot sample obtained 15 cm (6 in.) below the top surface of the liquid. See Fig. I. 3.1.1.27 tube or thief sample--a sample obtained with a sampling tube or special thief, either as a core sample or spot sample from a specific point in the tank or container. 3.1.1.28 upper sample--a spot sample taken from the middle of the upper one-third of the tank's contents (a distance of one-sixth of the liquid depth below the liquid's surface). See Fig. 1. 3.1.2 Other Terms: 3.1.2.1 automatic sampler--a device used to extract a representative sample from the liquid flowing in a pipe. (a) Discussion--The automatic sampler generally consists of a probe, a sample extractor, an associated controller, a flow measuring device, and a sample receiver. For additional information on an automatic sampler, see Practice D 4177. 3.1.2.2 dissolved water--water in solution in an oil. 3.1.2.3 emulsion--an oil/water mixture that does not readily separate. 3.1.2.4 entrained water--water suspended in the oil. (a) Discussion--Entrained water includes emulsions but does not include dissolved water. 3.1.2.5 free water--the water that exists as a separate phase. 3.1.2.6 intermediate container--the vessel into which all or part of the sample from a primary container/receiver is transferred for transport, storage, or ease of handling. 3.1.2.7 primary sample receiver/receptacle--a container in which a sample is initially collected. (a) Discussion--Examples of primary sampler containers include glass and plastic bottles, cans, core-type thief, and fixed and portable sample receivers. 3.1.2.8 stand pipes--verdcal sections of pipe or tubing extending from the gaging platform to near the bottom of tanks that are equipped with external or internal floating roofs. (a) Discussion--Stand pipes may also be found on ships and barges. 3.1.2.9 test specimen--the representative sample taken from the primary or intermediate sample container for analysis. TABLE 2

Uqu~ Depth (S of

Sampling Instructions for Horizontal Cylindrical Tanks

Samp~g L e ~ (% of DiameterAbove Bottom)

Compos~ Ssm~e (Proportionate Parts Of)

Diameter)

Upper

Middle

Lower

Upper

Middle

Lower

100 90 80 70 6O 50 40 30 20 10

80 75 70

50 50 50 50 5O 40

20 20 20 20 20 20 20 15 10 5

3 3 2

4 4 5

3 3 3

6

4

5 4

5 6 10 10 10 10

(~) D 4057 of the sample(s). Therefore, the sampling operation should be conducted before innage gaging, the associated temperature determination, and any other similar activity that could disturb the tank contents. 6.1.2.2 To avoid contamination of the oil column during the sampling operation, the order of precedence for sampling should start from the top and work downward, according to the following sampling sequence: surface, top, upper, middle, lower, outlet, clearance, all-levels, bottom, and running sample. 6.1.3 Equipment Cleanliness--The sampling equipment should be clean prior to commencing the sampling operation. Any residual material left in a sampling device or sample container from a previous sample or cleaning operation may destroy the representative character of the sample. It is good practice with light petroleum products to rinse the container with the product to be sampled prior to drawing samples.

4. Summary of Practice 4.1 This practice provides procedures for manually obtaining samples of petroleum and petroleum products of a liquid, semi-liquid or solid state from tanks, pipelines, drums, barrels, cans, tubes, bags, kettles and open-discharge streams. It addresses, in detail, the various factors which need to be considered in obtaining a representative sample. These considerations include the analytical tests to be conducted on the sample, the types of sample containers to be used and any special instructions required for special materials to be sampled. Test Method D 5854 can provide additional guidance. 5. Significance and Use 5.1 Representative samples of petroleum and petroleum products are required for the determination of chemical and physical properties, which are used to establish standard volumes, prices, and compliance with commercial and regulatory specifications. 5.2 The following concepts must be considered when selecting a specific sampling procedure.

6.1.4 Compositing of Individual Samples." 6.1.4.1 If the sampling procedure requires that several different samples be obtained, physical property tests may be performed on each sample or on a composite of the various samples. When the respective tests are performed on individual samples, which is the recommended procedure, the test results are averaged generally. 6.1.4.2 When a multiple tank composite sample is required, such as on board ships and barges, a composite tank sample may be prepared from the samples from different tanks when they contain the same material. In order for such a composite tank sample to be representative of the material contained in the various tanks, the quantity from the individual samples used to prepare the composite tank sample must be proportional to the volumes in the corresponding tanks. In most other compositing situations, equal volumes from the individual samples must be used. The method of compositing should be documented and care taken to preserve the integrity of the samples. It is recommended that a portion of each tank sample be retained separately (not composited) for retesting if necessary. 6.1.4.3 When compositing samples, exercise care to ensure sample integrity. Refer to Practice D 5854 for guidance on mixing and handling of samples. 6.1.4.4 Samples taken at specific levels, for example, upper-middle-lower capping will require a small portion of the sample to be poured out to create an ullage in the container before capping. All other samples shall be capped immediately and taken to the laboratory. 6.1.5 Sample TransfersmThe number of intermediate transfers from one container to another between the actual sampling operation and testing should be minimized. The loss of light hydrocarbons as the result of splashing, loss of water due to clingage, or contamination from external sources, or both, may distort test results, for example, density, sediment and water, product clarity. The more transfers between containers, the greater the likelihood one or both of these problems may occur. See Practice D 5854 for additional information concerning the handling and mixing of samples. 6.1.6 Sample StoragemExcept when being transferred, samples should be maintained in a closed container in order to prevent loss of light components. Samples should be

5.2.1 Objectiveof Manual Sampling: 5.2.1.1 The objective of manual sampling is to obtain a small portion (spot sample) of material from a selected area within a container that is representative of the material in the area or, in the case of running or all-level samples, a sample whose composition is representative of the total material in the container. A series of spot samples may be combined to create a representative sample.

5.2.2 Required Conditions for the Application of Manual Sampling: 5.2.2.1 Manual sampling may be applied under all conditions within the scope of this practice, provided that the proper sampling procedures are followed. 5.2.2.2 In many liquid manual sampling applications, the material to be sampled contains a heavy component (such as free water) which tends to separate from the main component. In these cases, manual sampling is appropriate under the following conditions. (a) Sufficient time must have elapsed for the heavy component to adequately separate and settle. (b) It must be possible to measure the level of the settled component in order to stay well above that level when drawing representative samples, unless all or part of the heavy component will be included in the portion of the tank contents to be identified. (c) When one or more of these conditions cannot be met, sampling is recommended and is accomplished by means of an automatic sampling system (see Practice D 4177). 6. Manual Sampling Considerations 6.1 The following factors must be considered in the development and application of manual sampling procedures: 6.1.1 Physical and Chemical Property Tests~The physical and chemical property tests to be performed on a sample will dictate the sampling procedures, the sample quantity required, and many of the sample handling requirements.

6.1.2 Sampling Sequence: 6.1.2.1 Any disturbance of the material in a tank that is to be sampled may adversely affect the representative character 631

~

D 4057 problem with solubility, contamination, or loss of light components. 7.4.1 In no circumstances shall nonlinear (conventional) polyethylene containers be used to store samples of liquid hydrocarbons. This is to avoid sample contamination or sample bottle failure. Used engine oil samples that may have been subjected to fuel dilution should not be stored in plastic containers. 7.4.2 Plastic bottles have an advantage in that they will not shatter like glass or corrode like metal containers. 7.5 Cans--When cans are to be used, they must have seams that have been soldered on the exterior surfaces with a flux of rosin in a suitable solvent. Such a flux is easily removed with gasoline, whereas many others are very difficult to remove. Minute traces of flux may contaminate the sample so that results obtained on tests such as dielectric strength, oxidation resistance, and sludge formation may be erroneous. Internal epoxy lined cans may have residual contamination and precautions should be taken to ensure its removal. Practice D 4306 should be used when taking samples for aviation fuels. 7.6 Container Closures--Cork stoppers, or screw caps of plastic or metal may be used for glass bottles. Corks must be of good quality, clean, and free from holes and loose bits of cork. Never use rubber stoppers. Prevent the sample from contacting the cork by wrapping fin or aluminum foil around the cork before forcing it into the bottle. Screw caps providing a vapor tight closure seal shall be used for cans. Screw caps must be protected by a disk faced with material that will not deteriorate and contaminate the sample. Containers used to take samples that will be tested for density or gravity shall have screw caps. 7.7 Cleaning Procedure--Sample containers must be clean and free from all substances which might contaminate the material being sampled (such as water, dirt, lint, washing compounds, naphtha and other solvents, soldering fluxes, acids, rust, and oil). Prior to further use, reusable containers such as cans and bottles should be rinsed with a suitable solvent. Use of sludge solvents to remove all traces of sediments and sludge may be necessary. Following the solvent wash, the container should be washed with a strong soap solution, rinsed thoroughly with tap water, and given a final rinse using distilled water. Dry the container either by passing a current of clean warm air through the container or by placing it in a hot dust-free cabinet at 40°C (104*F) or higher. When dry, stopper or cap the container immediately. Normally, it is not necessary to wash new containers. 7.7.1 Depending on service, receivers used in conjunction with automatic samplers may need to be washed with solvent between uses. In most applications, it is not desirable or practical to wash these receivers using soap and water as outlined above for cans and bottles. The cleanliness and integrity of all sample containers/receivers must be verified prior to use. 7.7.2 When sampling aviation fuel, Practice D4306 should be consulted for recommended cleaning procedures for containers that are to be used in tests for the determination of water separation, copper corrosion, electrical conductivity, thermal stability, lubricity, and trace metal content. 7.8 Sample Mixing Systems--The sample container should be compatible with the mixing system for remixing

protected during storage to prevent weathering or degradation from light, heat, or other potential detrimental conditions. 6.1.7 Sample Handling--If a sample is not uniform (homogeneous) and a portion of the sample must be transferred to another container or test vessel, the sample must be thoroughly mixed in accordance with the type of material and appropriate test method, in order to ensure the portion transferred is representative. Exercise care to ensure mixing does not alter the components within the sample, for example, loss of light ends. See Practice D 5854 for more detailed instructions.

7. Apparatus 7.1 Sample containers come in a variety of shapes, sizes, and materials. To be able to select the right container for a given application one must have knowledge of the material to be sampled to ensure that there will be no interaction between the sampled material and the container which would affect the integrity of the other. Additional considerations in the selection of sample containers is the type of mixing required to remix the contents before transferring the sample from the container and the type of laboratory analyses that are to be conducted on the sample. To facilitate the discussion on proper handling and mixing of samples, sample containers are referred to as either primary or intermediate containers. Regardless of the type of sample container used, the sample container should be large enough to contain the required sample volume without exceeding 80 % of the container capacity. The additional capacity is required for thermal expansion of the sample and enhances sample mixing. 7.2 GeneralContainer Design Considerations--Following are general design considerations for sample containers: 7.2.1 The bottom of the container should be sloped continuously downward to the outlet to ensure complete liquid withdrawal. 7.2.2 There should be no internal pockets or dead spots. 7.2.3 Internal surfaces should be designed to minimize corrosion, encrustation, and water/sediment clingage. 7.2.4 There should be an inspection cover/closure of sufficient size to facilitate filling, inspection, and cleaning. 7.2.5 The container should be designed to allow the preparation of a homogeneous mixture of the sample while preventing the loss of any constituents which affect the representativeness of the sample and the accuracy of the analytical tests. 7.2.6 The container should be designed to allow the transfer of samples from the container to the analytical apparatus while maintaining their representative nature. 7.3 Bottles (Glass)--Clear glass bottles may be examined visually for cleanliness and allows visual inspection of the sample for free water cloudiness, and solid impurities. Brown glass bottles afford some protection to the samples when light may affect the test results. 7.4 Bottles (Plastic)--Plastic bottles made of suitable material may be used for the handling and storage of gas oil, diesel oil, fuel oil, and lubricating oil. Bottles of this type should not be used for gasoline, aviation jet fuel, kerosine, crude oil, white spirit, medicinal white oil, and special boiling point products unless testing indicates there is no 632

~

D 4057 near the bottom. The running sample or the composite of the upper, middle, and lower sample may not represent the concentration of entrained water. 9.1.1.2 The interface between oil and free water is difficult to measure, especially in the presence of emulsion layers, or sludge. 9.1.1.3 The determination of the volume of free water is difficult because the free water level may vary across the tank bottom surface. The bottom is often covered by pools of free water or water emulsion impounded by layers of sludge or wax. 9.1.2 Automatic sampling in accordance with Practice D 4177 is recommended whenever samples of these materials are required for custody transfer measurements. However, tank samples may be used when agreed to by all parties to the transaction. 9.2 Gasoline and Distillate Products--Gasoline and distillate products are usually homogeneous, but they are ot~en shipped from tanks that have clearly separated water on the bottom. Tank sampling, in accordance with the procedures outlined in Section 13, is acceptable under the conditions covered in 5.2.2. 9.3 Industrial Aromatic Hydrocarbons--For samples of industrial aromatic hydrocarbons (benzene, toluene, xylene, and solvent naphthas), proceed in accordance with Sections 5.2.1, 7, and 10, and Sections 12.2 through 13, with particular emphasis on the procedures pertaining to the precautions for care and cleanliness. See Annex A1 for details. 9.4 Lacquer Solvents and Diluents: 9.4.1 When sampling bulk shipments of lacquer solvents and diluents which are to be tested using Test D 268, observe the precautions and instructions described in 9.4.2 and 9.4.3. 9.4.2 Tanks and Tank Cars--Obtain upper and lower samples (see Fig. 1) of not more than 1 L (qt) each by the thief or bottle spot sampling procedures outlined in 13.4. In the laboratory, prepare a composite sample of not less than 2 L/2 qts by mixing equal parts of the upper and lower samples. 9.4.3 Barrels, Drums, and Cans--Obtain samples from the number of containers per shipment as mutually agreed. In the case of expensive solvents, which are purchased in small quantities, it is recommended that each container be sampled. Withdraw a portion from the center of each container to be sampled using the tube sampling procedure (see 9.4.3) or bottle sampling procedure (see 13.4.2, although a smaller bottle may be used). Prepare a composite sample of at least 1 L (1 qt) by mixing equal portions of not less than 500 mL (1 pt) from each container sampled. 9.5 Asphaltic Materials--When sampling asphaltic materials that are to be tested using Test Method D 1856 or Test Method D 2172, obtain samples by the boring procedure in Section 17 or the grab procedure in Section 18. A sample of sufficient size to yield at least 100 g (I/4 lb) of recovered bitumen is required. About 1000 g (2 lb) of sheet asphalt mixtures usually will be sufficient. If the largest lumps in the sample are 2.5 cm (1 in.), 2000 g (4 lb) will usually be required, and still larger samples if the mixture contains larger aggregates. 9.6 Emulsified Asphalts--It is frequently necessary to test samples in accordance with the requirements of Specification

samples that have stratified to ensure that a representative sample is available for transfer to an intermediate container or the analytical apparatus. This is especially critical when remixing crude, some black products, and condensates for sediment and water analysis to ensure a representative sample. The requirements governing the amount of mixing and type of mixing apparatus differ depending upon the petroleum or petroleum product and the analytical test to be performed. Refer to Practice D 5854 for more detailed information. 7.8.1 When stratification is not a major concern, adequate mixing may be obtained by such methods as shaking (manual or mechanical), or use of a shear mixer. 7.8.2 Manual and mechanical shaking of the sample container are not recommended methods for mixing a sample for sediment and water (S&W) analysis. Tests have shown it is difficult to impart sufficient mixing energy to mix and maintain a homogeneous representative sample. Practice D 5854 contains more detailed information. 7.9 Other EquipmentmA graduated cylinder or other measuring device of suitable capacity is often required for determining sample quantity in many of the sampling procedures and for compositing samples. 7.10 Sampling DevicesmSampling devices are described in detail under each of the specific sampling procedures. Sampling devices shall be clean, dry, and free of all substances that might contaminate the material being sampled.

8. Special Precautions 8.1 This practice does not purport to cover all safety aspects associated with sampling. However, it is presumed that the personnel performing sampling operations are adequately trained with regard to the safe application of the procedures contained herein for the specific sampling situation. 8.2 A degree of caution is required during all sampling operations, but in particular when sampling certain products. Crude oil may contain varying amounts of hydrogen sulfide (sour crude), an extremely toxic gas. Annex A I provides precautionary statements that are applicable to the sampling and handling of many of these materials. 8.3 When taking samples from tanks suspected of containing flammable atmospheres, precautions should be taken to guard against ignitions from static electricity. Conductive objects, such as gage tapes, sample containers, and thermometers, should not be lowered into or suspended in a compartment or tank that is being filled, or immediately after cessation of pumping. Conductive material such as gage tape should always be in contact with gage tube until immersed in the fluid. A waiting period (normally 30 rain or more after filling cessation) will generally be required to permit dissipation of the electrostatic charge. In order to reduce the potential for static charge, nylon or polyester rope, cords, or clothing should not be used. 9. Special Instructions for Specific Materials 9.1 Crude Petroleum and Residual Fuel Oils: 9. I. 1 Crude petroleum and residual fuel oils usually are nonhomogeneous. Tank samples of crude oil and residual oils may not be representative for the following reasons: 9.1.1.1 The concentration of entrained water is higher 633

lib O 4057 them to temperatures above those necessitated by atmospheric conditions. 10.4.3 Sample ContainersmUse only brown glass or wrapped clear glass bottles as containers, since it is difficult to make certain that cans are free of contaminants, such as rust and soldering flux. Clean the bottles by the procedure described in 7.7. Rinse thoroughly with distilled water, dry, and protect the bottles from dust and dirt. 10.4.4 SamplingmA running sample obtained by the procedure in 13.5 is recommended because the sample is taken directly in the bottle. This reduces the possibility of air absorption, loss of vapors, and contamination. Just before sampling, rinse the bottle with the product to be sampled.

D977, and Test Methods D 244. Obtain samples from tanks, tank cars, and tank trucks by the bottle sampling procedure outlined in 13.4.2 using a bottle that has a 4-cm (1 l/2-in.) diameter or larger mouth. Refer to Fig. 1 and Table 2 for sampling locations. Use the dipper procedure in Section 15 to obtain samples for fill or discharge lines. Sample packages in accordance with Table 3. If the material is solid or semisolid, use the boring sampling procedure described in Section 17. Obtain at least 4 L (1 gal) or 4.5 Kg (10 lbs) from each lot or shipment. Store the samples in clean, airtight containers at a temperature of not less than 4"C (40*F) until the test. Use a glass or black iron container for emulsified asphalts of the RS- 1 type.

11. Special Instructions for Specific Applications 11.1 Marine Cargoes of Crude Oils: 11.1.1 Samples of ship or barge cargoes of crude petroleum may be taken by mutual agreement by the following methods: 11.1.1.1 From the shore tanks before loading and both before and after discharging as in Section 13. 11.1.1.2 From the pipeline during discharging or loading. Pipeline samples may be taken either manually or with an automatic sampler. If the pipeline requires displacement or flushing, exercisecare that the pipeline sample includes the entirecargo and none of the displacement. Separate samples may be required to cover the effectof the line displacement on the prior or following transfer. I I.I.1.3 From the ship'sor barge's tanks afterloading or before discharging. An all-levelssample, running sample, upper-middle-lower sample, or spot samples at agreed levels may be used for sampling each cargo compartment of a ship or barge. 11.1.2 Ship and barge samples may be taken either through open hatches or by use of equipment designed for closed systems. I I.I.3 Normally, when loading a marine vessel,the shore tank sample or the pipeline sample taken from the loading line is the custody transfer sample. However, ship's/barge's tank samples may also be tested for sediment and water (S&W) and for other quality aspects, when required. The resultsof these ship's/barge'stank sample tests,togetherwith the shore tank sample tests,may be shown on the cargo certificate. 11.1.4 When discharging a ship/barge, the pipeline sample taken from a properly designed and operated automatic line sampler, in the discharge line, should be the custody transfer sample. Where no proper line sample is available, the ship's/barge's tank sample can be the custody transfer sample except where specifically exempted. 11.1.5 Samples of ship/barge cargoes of finished products are taken from both shipping and receiving tanks and from the pipeline, if required. In addition, the product in each of the ship/barge tanks should be sampled after the vessel is loaded or just before unloading.

10. Special Instructions for Specific Tests 10.1 General--Special sampling precautions and instructions are required for some ASTM test methods and specifications. Such instructions supplement the general procedures of this practice and supersede them if there is a conflict. 10.2 Distillation of Petroleum Products~When obtaining samples of natural gasoline that are to be tested using Test Method D 86, the bottle sampling procedure described in 13.4.2 is the preferred technique, with the exception that pre-cooled bottles and laboratory compositing is required. Before obtaining the sample, pre-cool the bottle by immersing it in the product, allowing it to fill, and discard the first filling. If the bottle procedure cannot be used, obtain the sample by the tap procedure and with the use of the cooling bath, as described in 13.6. Do not agitate the bottle while drawing the sample. After obtaining the sample, close the bottle immediately with a tight-fitting stopper, and store it in an ice bath or refrigerator at a temperature of 0 to 4.5"C (32 to 400F). 10.3 Vapor Pressure~When sampling petroleum and petroleum products that are to be tested for vapor pressure, refer to Practice D 5842. 10.4 Oxidation Stability: 10.4.1 When sampling products that are to be tested for oxidation stability in accordance with Test Method D 525, Test Method D 873, or equivalent methods, observe the precautions and instructions that follow. 10.4.2 PrecautionsmVery small amounts (as low as 0.001%) of some materials, such as inhibitors, have a considerable effect upon oxidation stability tests. Avoid contamination and exposure to light while taking and handling samples. To prevent undue agitation with air, which promotes oxidation, do not pour, shake, or stir samples to any greater extent than necessary. Never expose TABLE 3

Minimum Number of Packages to b e Selected for Sampling

Packages in Lot

Packages to be Sampled

1 to 3 4 to 64 65 to 125 126 to 216 217 to 343 344 to 512 513 to 729 730 to 1000 1001 to 1331

all 4 5 6 7 8 9 10 11

Packages in Lot 1332 to 1728 1729 to 2197 2198 to 2744 2745 to 3375 3376 to 4096 4097 to 4913 4914 to 5832 5833 to 6859 6850 and greater

Packages to be Sampled 12 13 14 15 16 17 18 19 20

NOTE 4--Refer to M P M S Chapter 17 for additional requirements associated with sampfing materials in marine vessels.

11.2 Crude Oil Gathered By Truck--Refer to MPMS Chapter 18.1 for additional sampling requirements when gathering crude oil by tank truck. l l.3 Tank Cars--Sample the material after the car has 634

(~ D 4057 been loaded or just before unloading. 11.4 Package Lots (Cans, Drums, Barrels, or Boxes)-Take samples from a sufficient number of the individual packages to prepare a composite sample that will be representative of the entire lot or shipment. Select at random the individual packages to be sampled. The number of random packages will depend on several practical considerations, such as (1) the tightness of the product specifications; (2) the sources and type of the material and whether or not more than one production batch may be represented in the load and (3) previous experience with similar shipments, particularly with respect to the uniformity of quality from package to package. In most cases, the number specified in Table 4 will be satisfactory.

be sampled and drained before it is filled with the actual sample. 12.2.5 The transfer of crude oil samples from the sample apparatus/receiver to the laboratory glassware in which they will be analyzed requires special care to maintain their representative nature. The number of transfers should be minimized. Mechanical means of mixing and transferring the samples in the sample receiver are recommended. 12.3 Sample Handling: 12.3.1 Volatile SamplesmAll volatile samples of petroleum and petroleum products shall be protected from evaporation. Transfer the product from the sampling apparatus to the sample container immediately. Keep the container closed except when the material is being transferred. After delivery to the laboratory, volatile samples should be cooled before the containers are opened. 12.3.2 Light Sensitive SamplesmIt is important that samples sensitive to light, such as gasoline, be kept in the dark, if the testing is to include the determination of such properties as color, octane, tetraethyl lead and inhibitor contents, sludge forming characteristics, stability tests, or neutralization value. Brown glass bottles may be used. Wrap or cover clear glass bottles immediately. 12.3.3 Refined Materials~Protect highly refined products from moisture and dust by placing paper, plastic, or metal foil over the stopper and the top of the container. 12.3.4 Container Outage~Never fill a sample container completely. Allow adequate room for expansion, taking into consideration the temperature of the liquid at the time of filling, and the probable maximum temperature to which the filled container may be subjected. Adequate sample mixing is difficult if the container is more than 80 % full. 12.4 Sample Labeling--Label the container immediately after a sample is obtained. Use waterproof and oil proof ink or a pencil hard enough to dent the tag. Soft pencil and ordinary ink markers are subject to obliteration from moisture, oil smearing, and handling. Include the following information on the label: 12.4.1 Date and time (the period elapsed during continuous sampling and the hour and minute of collection for dipper samples), 12.4.2 Name of the sampler, 12.4.3 Name and number and owner of the vessel, car, or container, 12.4.4 Grade of material, and 12.4.5 Reference symbol or identification number. 12.5 Sample Shipment--To prevent loss of liquid and vapors during shipment and to protect against moisture and dust, cover the stoppers of glass bottles with plastic caps that have been swelled in water, wiped dry, placed over the tops of the stoppered bottles, and allowed to shrink tightly in place. Before filling metal containers, inspect the lips and caps for dents, out-of-roundness, or other imperfections. Correct or discard the cap or container, or both. After filling, screw the cap tightly and check for leaks. Appropriate governmental and carder regulations applying to the shipment of flammable liquids must be observed.

12. Sampling Procedures (General) 12.1 The standard sample procedures described in this practice are summarized in Table 1. Alternative sampling procedures may be used if a mutually satisfactory agreement has been reached by the parties involved. It is recommended that such agreements be put in writing and signed by authorized officials. 12.2 Precautions: 12.2.1 Extreme care and good judgment are necessary to ensure that samples are obtained that represent the general characteristics and average condition of the material. Clean hands are important. 12.2.2 Since many petroleum vapors are toxic and flammable, avoid breathing them, igniting them from an open flame, burning embers, or a spark produced by static electricity. All safety precautions specific to the material being sampled should be followed. 12.2.3 When sampling relatively volatile products more than 13.8 kPa (2 psia) RVP, the sampling apparatus shall be fiUed and allowed to drain before drawing the sample. If the sample is to be transferred to another container, this container shall also be rinsed with some of the volatile product and then drained. When the actual sample is emptied into this container, the sampling apparatus should be upended into the opening of the sample container and should remain in this position until the contents have been transferred so that no unsaturated air will be entrained in the transfer of the sample. 12.2.4 When sampling nonvolatile liquid products, 13.8 kPa (2 psia) RVP or less, sampling apparatus shall be filled and allowed to drain before drawing the actual sample. If the actual sample is to be transferred to another container, the sample container shall be rinsed with some of the product to TABLE 4

Spot Sampling Requirement~

NoTE--When samples are I'equlred at more thai3orte location in the tank, the samples shall be obtained beginning with the upper sample first and progressing sequentially to the lower sample. Tank Capacity/Liquid Level Tank capacity less than or equal to 159 ma (1 000 bbls) Tank capacity greater than 159 ma (1 000 bbls) Level < 3 m (10 ft) 3 m (10 ft) < Level s 4.5 m (15 ft) Level > 4.5 m (15 ft)

Required Samples Upper

Middle

Lower

X X

X

X

13. Tank Sampling 13.1 Samples should not be obtained from within solid stand pipes as the material is normally not representative of

X X X

X

X X

635

~

D 4057

the material in the tank at that point. Stand pipe samples should only be taken from pipes with at least two rows of overlapping slots.See Fig. 2. 13.2 When sampling crude oil tanks with diameters in excess of 45 m 050 it),additional samples should be taken from any other availablegaging hatches located around the perimeter of the tank roof, safety requirements permitting. All the samples should be individually analyzed using the same test method and the results should then be averaged arithmetically. 13.3 Composite Sample Preparation--A composite spot sample is a blend of spot samples mixed volumetrically proportional for testing. Some tests may also be made on the spot samples before blending and the results averaged. Spot samples from crude oil tanks are collected in the following ways: 13.3.1 Three-way--On tanks larger than 159 m 3 (1000 bbls) capacity, which contain in excess of 4.5 m (15 it) ofoil, equal volume samples should be taken at the upper, middle, and lower or outlet connection of the merchantable oil, in the order named. This method may also be used on tanks up to and including a capacity of 159 m 3 (1000 bbls). 13.3.2 Two-way---On tanks smaller than 159 m 3 (1000 bbls) capacity, which contain in excess of 3 m (10 it) and up to 4.5 m (15 it) of oil, equal volume samples should be taken at the upper and lower, or outlet connection of the merchantable oil, in the order named. This method may also be used on tanks up to and including a capacity of 159 m 3 (1000 bbls). 13.4 Spot Sampling Methods--The requirements for spot sampling are shown in Table 4. For sampling locations, see Fig. 1. 13.4.1 Core Thief Spot SamplingProcedure." 13.4.1.1 Application--Thecore thief spot sampling procedure may be used for sampling liquids of 101 kPa (14.7 psia) RVP or less in storage tanks, tank cars, tank trucks, ship, and barge tanks. 13.4.1.2 Apparatus--A typical core-type thief is shown in Fig. 3. The thief shall be designed so that a sample can be obtained within 2.0 to 2.5 cm (3/4 to 1 in.) of the bottom or at any other specificlocationwithin the tank or vessel.The size of the core thief should be selected depending upon the volume of the sample required. The thiefshould be capable of penetrating the oil in the tank to the required level, mechanically equipped to permit fallingat any desired level,

i +

0

RG. 3 Core-TypeSamplingThief

and capable of being withdrawn without undue contamination of the contents. The thief may include the following features: (a) Uniform cross section and bottom closure, (b) Extension rods for use in obtaining samples at levels corresponding with requirements for high connections or for samples to determine high settled sediment and water levels, (c) Sediment and water gage for determining the height of sediment and water in the thief, (d) A clear cylinder that facilitates observing the gravity and temperature of the oil during a gravity test; it also should be equipped with a windshield, (e) An opener to break the tension on the valve or slide at any desired level, (f) A thief cord marked so that the sample can be taken at any depth in the vertical cross section of the tank, (g) A hook to hang the thief in the hatch vertically, and (h) Sample cocks for obtaining samples for determination

i I

TABLE 5 WeightedSamplingBottle or Beaker Material

FIG. 2

I

I

I

I

Light lubdcaUng oils, kerosines, gasolines, transparent gas oils, diesel fuels, distillates Heavy lubricating oils, nontransparent gas oils Ught crude oils less than 43 cTs at 40°C Heavy crude and fuel oils

Stand Pipe (with ovedapping slots)

636

Diameter of Opening cm

in.

2

4/,

4 2 4

¾

1+/=

tt~ O 4057 13.4.2.1 ApplicationmThe bottle or beaker spot sampling procedure may be used for sampling liquids of 101 kPa (14.7 psia) RVP or less in storage tanks, tank cars, tank trucks, ship, and barge tanks. Solids or semi-liquids that can be liquified by heat may be sampled using this procedure, provided they are true liquids at the time of sampling. 13.4.2.2 Apparatus--The bottle and beaker are shown in Fig. 4. A graduated cylinder and possibly a sample container are required for use with this procedure. The sampling cage shall be made of a metal or plastic suitably constructed to hold the appropriate container. The combined apparatus shall be of such weight as to sink readily in the material to be sampled, and provision shall be made to fill the container at any desired level (see Fig. 4A). Bottles of special dimensions are required to fit a sampling cage. The use of sampling cage is generally preferred to that of a weighted sampling beaker for volatile products since loss of light ends is likely to occur when transferring the sample from a weighted sampling beaker to another container. 13.4.2.3 Procedure: (a) Inspect the sampling bottle or beaker, graduated cylinder, and sample container for cleanliness and use only clean, dry equipment. (b) Obtain an estimate of the liquid level in the tank. Use an automatic gage or obtain an outage measurement if required. (c) Attach the weighted line to the sample bottle/beaker or place the bottle in a sampling cage, as applicable. (d) Insert the cork in the sampling bottle or beaker. (e) Lower the sampling assembly to the required location. See Table 5. (f) At the required location, pull out the stopper with a sharp jerk of the sampling line. (g) Allow sufficient time for the bottle/beaker to completely fdl at the specific location. (h) Withdraw the sampling assembly. (i) Verify the bottle/beaker is completely full. If not full,

of sediment and water spaced at the 10-cm (4-in.) and 20-cm (8-in.) marker levels. (i) A graduated cylinder and sample container may also be required for use with this procedure. 13.4.1.3 Procedure: (a) Inspect the thief, graduated cylinder, and sample container for cleanliness and use only clean, dry equipment. (b) Obtain an estimate of the liquid level in the tank. Use an automatic gage or obtain an outage measurement, if required. (c) Check the thief for proper operation. (d) Open the bottom closure, and set the trip hook in the trip rod. (e) Lower the thief to the required location. See Table 5. (f) At the required location, close the bottom closure on the thief with a sharp jerk of the line. (g) Withdraw the thief. (h) If only a middle sample is required, pour all of the sample into the sample container. If samples are required at more than one location, measure out a specified amount of sample with the graduated cylinder, and deposit it in the sample container. NOTE 5--The amount of sample measured willdepend upon the size of the thiefand the tests to be performedbut should be consistentfor the samples taken at differentlevels. (i) Discard the remainder of the sample from the sampiing thief as required. (j) Repeat steps (d) through (i) to obtain a sample(s) at the other sample location(s) required by Table 5 or to obtain additional sample volume, if only a middle sample is required. (k) Install the lid on the sample container. (1) Label the sample container. (m) Return the sample container to the laboratory or other facility for mixing and testing. 13.4.2 Bottle/BeakerSpot Sampling:

/

Copper wire -handle

"•

Clove hitch

~

Eyelet

C&r Cork arrangements l-Litre (1 qt ) Sample Weighted Cage (can be fabricated to fit any size bottle)

Sheet - lead

Beaker

1-Litre (1 qt.) Weighted Beaker

A FIG. 4

Copper wire lugs

Assemblies for B o t t l e / B e a k e r S a m p l i n g

637

(~ D 4057 diameters for various applications are given in Table 5. 13.5.3 Procedure: 13.5.3.1 Inspect the sampling bottle and sample container for cleanliness and use only clean, dry equipment. 13.5.3.2 Attach the weighted line to the sample bottle, or place the bottle in a sampling cage. 13.5.3.3 If required to restrict the Idling rate, insert a notched cork in the sampling bottle. 13.5.3.4 At a uniform rate, lower the bottle assembly as near as possible to the level of the bottom of the outlet connection or swing line inlet and, without hesitation, raise it such that the bottle is approximately three-fourths full when withdrawn from the liquid. 13.5.3.5 Verify that a proper quantity of sample has been obtained. If the bottle is more than three-fourths full, discard the sample and repeat 13.5.3 and 13.5.4, adjusting the rate at which the bottle assembly is lowered and raised. Alternatively, repeat 13.5.3 and 13.5.4 using a different notched cork. 13.5.3.6 Empty the contents of the bottle into the sample container, if necessary. 13.5.3.7 If additional sample volume is required, repeat 13.5.3.3 through 13.5.3.6. 13.5.3.8 Install the lid on the sample container. 13.5.3.9 Label the sample container. 13.5.3.10 Disconnect the line from the bottle, or remove the sample bottle from the sampling cage, as applicable. 13.5.3.11 Return the sample container to the laboratory or other facility for mixing and testing. 13.6 Tap Sampling: 13.6.1 Application--The tap sampling procedure is applicable for sampling liquids of 101 kPa (14.7 psia) RVP or less in tanks that are equipped with suitable sampling taps. This procedure is recommended for volatile stocks in tanks of the breather and balloon-roof type, spheroids, and so forth. (Samples may be taken from the drain cocks of gage glasses, if the tank is not equipped with sampling taps.) 13.6.2 Apparatus: 13.6.2.1 Typical sample tap assembly is shown in Fig. 5. Each tap should be a minimum of 1.25 cm (1/2 in.) in

empty the bottle/beaker and repeat the procedure beginning with (d). (j) If only this spot sample is required for compositing will be accomplished elsewhere, pour all of the sample into the sample container or discard one-fourth of the sample, stopper the bottle/beaker, and proceed to (n). If composited samples are required at more than one location, measure out a specific amount of sample with a graduated cylinder and deposit it in the sample container. NOTE 6--The amount of sample measured will depend upon the size of the bottle/beaker and the tests to be performed but should be consistent for the samples taken at different levels. (k) Discard the remainder of the sample from the sampling bottle/beaker as required. (l) Repeat (c) through (k) to obtain a sample(s) at the other sample location(s) required by Table 5 or to obtain additional sample volume if only a middle sample is required. (m) Install the closure on the sample container. (n) Disconnect the line from the bottle, or remove the sample bottle from the sampling cage, as applicable. (o) Label the sample container. (p) Return the sample container to the laboratory or other facility for mixing and testing. 13.5 Running or All-Level Sampling: 13.5.1 Application--The running and all levels sample procedures are applicable for sampling liquids of 101 kPa (14.7 psia) RVP or less in tank cars, tank trucks, shore tanks, ship tanks, and barge tanks. Solids or semi-liquids that can be liquified by heat may be sampled by this procedure, provided they arc true liquids at the time of sampling. A running/all-levels sample is not necessarily a representative sample because the tank volume may not be proportional to the depth and because the operator may not be able to raise the sampler at the rate required for proportional filling. The rate of filling is proportional to the square root of the depth of immersion. 13.5.2 ApparatusmA suitable sampling bottle or beaker, as shown in Figs. 4A and B, equipped with notched cork or other restricted opening is required. Recommended opening

Optional-~

Optional /~/

t,

Lineor tankwall

Lineor tank wall

FIG. 5

Assemblies for Tap Sampling

638

"/Z

I~

(~@) D 4057 diameter. Taps 2.0 cm (¾-in.) may be required for heavy, viscous liquids (for example, crude oil of .9465 density (18" API) or less). On tanks that are not equipped with floating roofs, each sample tap should extend into the tank a minimum of 10 cm (4 in.). Normally, a sample tap should be equipped with a delivery tube which permits the tilling of the sample container from the bottom. 13.6.2.2 For tanks having a side outlet, a tap for obtaining a clearance sample may be located 2 cm (4 in.) below the bottom of the outlet connection. Other requirements for sample taps are outlined in Table 6. 13.6.2.3 Clean, dry glass bottles of convenient size and strength to receive the samples arc required. 13.6.3 Procedure: 13.6.3.1 Inspect the sample container(s) and graduated cylinder for cleanliness. If required, obtain clean equipment or clean the existing equipment with a suitable solvent, and rinse with the liquid to be sampled prior to proceeding to 13.6.3.2. 13.6.3.2 Obtain an estimate of the liquid level in the tank. 13.6.3.3 If the material to be sampled is 101 kPa (14.7 psia) RVP or less, connect the delivery tube directly to the sample tap as required. 13.6.3.4 Flush the sample tap and piping until they have been completely purged. 13.6.3.5 Collect the sample in a sample container or a graduated cylinder in accordance with the requirements set forth in Table 7. If samples arc to be obtained from different taps, use a graduated cylinder to measure the appropriate sample quantity. Otherwise, collect the sample directly in the sample container. If a delivery tube is used, ensure the end of the delivery tube is maintained below the liquid level in the graduated cylinder or sample container during the withdrawal of the sample. 13.6.3.6 If the sample was collected in a graduated cylinder, deposit the sample in the sample container. 13.6.3.7 Disconnect the delivery tube and cooler as applicable. 13.6.3.8 If required in accordance with Table 7, repeat 13.6.3 through 13.6.3.7 to obtain samples from additional taps. 13.6.3.9 Install the lid on the sample container. 13.6.3.10 Label the sample container. 13.6.3.11 Return the sample container to the laboratory or other facility for mixing and testing.

TABLE 7

Tank capacity less than or equal to 1590 ms (10 000 bins) Level below middle tap Level above middle tap~clos~t to middle tap Level above middle tap--closest to upper tap Level above upper tap Tank capacity greater than 1590 ma (10 000 bbls)

TABLE 6

Number of Sets Number of taps per set, min Vertical location Upper tap Lower tap Middle tap(s) Circumferential location From inlet From outlet/drain

Sampling Requirements

Total sample from the lower tap. Equalamounts from the middle and lower taps. =/s of total sample from the middle tap and 1/, of total sample from the lower tap. Equal amounts from the upper, middle, and lower taps. Equalamounts from all submerged taps. A minimum of three taps are required representlog different volumes.

is applicable for obtaining bottom samples or for obtaining samples of semi-liquids in tank cars and storage tanks. The core thiefis also widely used in sampling crude petroleum in storage tanks. In this application, it m a y be used for taking samples at different levels, as well as for bottom samples of nonmcrchantablc oil and water at the bottom of the tank. The thief can be used in some cases to obtain a quantitative estimate of the water at the bottom of a tank. 13.7.1.2 Apparatus--The thief shall be designed so that a sample can bc obtained within 2 to 2.5 c m (3/4to I in.)of the bottom of the car or tank. The core type thief is shown in Fig. 3. This type is lowered into the tank with the valve open to permit the hydrocarbon to flush through the container. W h e n the thief strikes the bottom of the tank, the valve shuts automatically to trap a bottom sample. 13.7.1.3 Procedure--Lower the clean, dry thief slowly through the dome of the tank car or tank hatch until itgently bumps the bottom. Allow the thief to filland settle,gently raise 5 to I0 c m (2 to 4 in.) and then lower the thief until it strikes the bottom and the valve closes. Remove the thief from the tank and transfer the contents to the sample container. Close and label the container immediately and deliver it to the laboratory. 13.7.2 Closed-Core Bottom Sampling." 13.7.2.1 Application--The closed-corcthiefsampling procedurc is applicable for obtaining bottom samples of tank cars and storage tanks. In sampling crude petroleum in storage tanks, the thief might be used for obtaining bottom samples of nonmcrchantable oil and water at the bottom of the tank. 13.7.2.2 Apparatus--The thief shall be designed so that a sample can be obtained within 1.25 c m (I/2in.) of the bottom of the tank car or tank. A closed-core type thief is shown in Fig. 6. This type of thief has a projecting stem on the valve rod which opens the valves automatically as the stem strikes the bottom of the tank. The sample enters the container through the bottom valve, and air is released simultaneously through the top valve. The valves snap shut when the thief is withdrawn. Use only clean, dry cans, or glass bottles as sample containers. 13.7.2.3 Procedure--Lower the clean, dry thief through the dome of the tank car or tank hatch until it strikes the bottom. W h e n full, remove the thief and transfer the contents to the sample container. Close and label the container immediately and deliver it to the laboratory. 13.7.3 Extended- Tube Sampling:

13.7 Bottom Sampling: 13.7.1 Core Thief Bottom Sampling: 13.7.1.1 Application--The core thief sampling procedure

Tank Capadty

Tap Sampling Requirements

Tank Capactty/Uquld Level

Sample Tap Specifications 1590 ma (10 000 10his) Greater Than 1590 ma Or Less (10 000 bbls) 1 2A 3 5 45 cm (18 in.) from top of shell even with bottom of outlet equally spaced between upper and lower tap 2.4 m (8 ft), min 1.5 m (6 ft), min

A The respective sets of taps should be located on opposite sides of the tank.

639

~

'.

D 4057 manually operated pump. For support purposes and to establish a known sampling point, the tubing is attached to the weighted end of a conductive wire or tape such that the open end of the tube is located approximately 1.25 cm (V2 in.) above the rip of the weight. The tubing and wire (or tape) shall be long enough to extend to the bottom (reference height) of the vessel or storage tank from which the sample is to be obtained. A grounding cable shall be provided for the assembly. In addition to the sampler, a clean, dry bottle or other appropriate container is required to collect each sample. 13.7.3.3 Procedure." (a) Assemble the extended-tube sampler. (b) Following assembly, prime the tubing and pump with water and close-off (ensure it is not vented to atmosphere) the top end of the assembly to prevent loss of priming water as the sampling tube is lowered. Connect the grounding cable to the ship or barge tank or storage tank, and lower the weighted end of the sampler to the bottom. (c) Begin the sampling operation by slowly and steadily operating the manual pump. To reduce the possibility of capturing a contaminated sample, initially purge and discard a volume greater than twice the sampling assembly's capacity. Collect the sample(s) directly in a clean, dry bottle(s) or other appropriate container(s). (d) If a sample at a different level within the bottom water layer is required, raise the weighted bob and tubing to the new level above the bottom. Purge the residual water in the tubing assembly (twice the sampler assembly volume), and collect the new sample(s). (e) After each sample has been collected, immediately close and label the bottle (or container) in preparation for delivery to the laboratory. (f) When the sampling operation is complete, clean and disassemble the sampler components.

Line for lowering

I I I I I I I I I I I I I I I I I I I I I

I

I I

I I

t

I

I

I

" ",

4 lugs

I FIG. 6

Closed-Core Type Sampling Thief

13.7.3.1 ApplicationmThe extended-tube sampling procedure may be used only for obtaining bottom water samples primarily on ships and barges. The procedure may be used for sampling bottom water in shore tanks, but no specific guidelines for such use are available. 13.7.3.2 Apparatus~A typical extended-tube sampling assembly is shown in Fig. 7. The extended-tube sampler consists of a flexible tube connected to the suction of a

14. Manual Pipeline Sampling 14.1 Application--This manual pipeline sampling procedure is applicable to liquids of 101 kPa (14.7 psia) RVP or less and semi-liquids in pipelines, filling lines, and transfer lines. The continual sampling of pipeline streams by automarie devices is covered in Practice D 4177. When custody transfer is involved, continuous automatic sampling is the preferred method as opposed to manual pipeline samples. In the event of automatic sampler failure, manual sampling may be needed. Such manual samples should be taken as representatively as possible. 14.2 ApparatusmA sampling probe is used to direct sample from the flowing stream. All probes should extend into the center one-third of the pipe's cross-section area. All probes inlets should be facing upstream. Probe designs that are commonly used are shown in Fig. 8 and can be: 14.2.1 A tube beveled at a 45* angle as shown in Fig. 8A. 14.2.2 A short radius elbow or pipe bend. The end of the probe should be chamfered on the inside diameter to give a sharp entrance edge (see Fig. 8B). 14.2.3 A closed-end tube with a round orifice spaced near the closed end as shown in Fig. 8C. 14.3 ProbeLocation: 14.3.1 Since the fluid to be sampled may not always be homogeneous, the location, position, and size of the sam-

Manual sampling pump

Sampling tube

Support wire or tape - -

Weight Ill

J

FIG. 7

Typical Extended-Tube Sampler

640

i~

D 4057

End of probe closed orifice facing upstream 6.4 mm - 5 cm (1/4"-2") pipe o r tubing \ 1 Manufacturers "~1[ ~ I [ standard

6.4 mm - 5 cm (1/4"-2") pipe or tubing 45" Bevel

To a,ve A

~

To valve

/6.4

~

mm-5cm (1/4" -2") pipe or tubing

,H-~ . To valve

B

NOTE--Probesmay be fitted withvalvesor plug cocks. The probeshouldbe orientedhorizontally. FIG. 8 Probesfor Spot Manual SampleB

piing probe should be such as to minimize any separation of water and heavier particles that would make their concentration different in the gathered sample than in the main stream. 14.3.2 The probe should always be in a horizontal plane to prevent drain back of any part of the sample to the main stream. 14.3.3 The sampling probe should preferably be located in a vertical run of pipe where such a vertical run can be provided. The probe may also be located in a horizontal run of pipe. The flowing velocity must be high enough to provide adequate turbulent mixing (see Practice D 4177). 14.3.4 Where adequate flowing velocity is not available, a suitable device for mixing the fluid flow should be installed upstream of the sampling tap to reduce stratification to an acceptable level. If flow has been vertical for a sufficient distance, as in a platform riser, such a device may not be necessary even at low flow rates. Some effective methods for obtaining adequate mixing are: a reduction in pipe size, a series of baffles, and orifice or perforated plate, or combination of any of these methods. The design or sizing of the device is optional with the user, as long as the flowing stream is sufficiently well mixed to provide a representative sample from the probe. 14.3.5 Sampling lines, used in conjunction with probes, should be as short as is practical and should be cleared before any samples are taken. 14.3.6 When sampling semi-liquids, it may be necessary to heat the sample line, valves, and receiver to a temperature just sufficient to keep the material liquid and to ensure accurate sampling and mixing. 14.3.7 To control the rate at which the sample is withdrawn, the probe should be fitted with valves or plug cocks. 14.4 Procedure: 14.4.1 Adjust the valve or plug cock from the sampling probe so that a steady stream is drawn from the probe. Whenever possible, the rate of sample withdrawal should be such that the velocity of liquid flowing through the probe is approximately equal to the average linear velocity of the stream flowing through the pipeline. Measure and record the rate of sample withdrawal as gallons per hour. Divert the sample stream to the sampling container continuously or intermittently to provide a quantity of sample that will be of sufficient size for analysis.

14.4.2 In sampling crude petroleum and other petroleum products, samples of 250 mL (1/2pt) or more should be taken every hour or at increments less than an hour, as necessary. By mutual agreement, the sample period or sample size, or both, may be varied to accommodate the parcel size. It is important that the size of the samples and the intervals between the sampling operations be uniform for a uniform flow rate. When the main stream flow rate is variable, the sampling rate and volume must be varied accordingly so that the flow is proportional. In practice, this is difficult to accomplish manually. 14.4.3 Each sample of crude petroleum should be placed in a closed container, and at the end of the agreed upon time period, the combined samples should be mixed and a composite sample taken for test purposes. Refer to 12.3 for mixing and handling. The sample container should be stored in a cool, dry place; exposure to direct sunlight should be avoided. 14.4.4 Alternatively, line samples may be taken at regular intervals and individually tested. The individual test results may be arithmetically averaged, adjusting for variations in flow rate during the agreed upon time period. 14.4.5 Either composite or arithmetically averaged results are acceptable by mutual agreement. 14.4.6 With either procedure, always label each sample and deliver to the laboratory in the container in which it was collected.

15. Dipper Sampling 15.1 Application--The dipper sampling procedure is applicable for sampling liquids of 13.8 kPa (2 psia) RVP or less and semi-liquids where a free or open discharge stream exists, as in small filling and transfer pipelines, 5 cm (2 in.) in diameter or less, and filling apparatus for barrels, packages, and cans. 15.2 Apparatus--Use a dipper with a flared bowl and a handle of conventional length made of a material such as tinned steel that will not affect the product being tested. The dipper should have a capacity suitable for the amount to be collected and must be protected from dust and dirt when not being used. Use a clean, dry sample container of the desired size. 15.3 Procedure--Insert the dipper in the free-flowing stream so that a portion is collected from the full cross 641

~) D 4057 section of the stream. Take portions at time intervals chosen so that a complete sample proportional to the pumped quantity is collected. The gross amount of sample collected should be approximately 0.1 percent, but not more than 150 L (40 gal) of the total quantity being sampled. Transfer the portions into the sample container as soon as they are collected. Keep the container closed, except when pouring a dipper portion into it. As soon as all portions of the sample have been collected, close and label the sample container and deliver it to the laboratory.

16. Tube Sampfing 16.1 Application--The tube sampling procedure is applicable for sampling liquids of 13.8 kPa (2 psia) RVP or less and semi-liquids in drums, barrels, and cans. 16.2 Apparatus--Either a glass or metal tube may be used, designed so that it will reach to within about 3 mm (I/8 in.) of the bottom of the container. Capacity of the tube can vary from 500 mL to 1 L (1 pt to 1 qt). A metal tube suitable for sampling 189 L (50-gal) drums is shown in Fig. 9. Two rings soldered to opposite sides of the tube at the upper end are convenient for holding it by slipping two fingers through the rings, thus leaving the thumb free to close the opening. Use clean, dry cans, or glass bottles for sample containers. 16.3 Procedure: 16.3.1 Place the drum or barrel on its side with the bung up. If the drum does not have a side bung, stand it upright and sample from the top. If detection of water, rust, or other insoluble contaminants is desired, let the barrel or drum remain in this position long enough to permit the contami-

FIG. 9

Typical Drum or Barrel Sampler

nants to settle. Remove the bung and place it beside the bung hole with the oily side up. Close the upper end of the clean, dry sampling tube with the thumb, and lower the tube into the oil to a depth of about 30 cm (1 ft). Remove the thumb, allowing oil to flow into the tube. Again, close the upper end with the thumb and withdraw the tube. Rinse the tube with the oil by holding it nearly horizontal and turning it so that the oil comes in contact with that part of the inside surface that will be immersed when the sample is taken. Avoid handling any part of the tube that will be immersed in the oil during the sampling operation. Discard the rinse oil and allow the tube to drain. Insert the tube into the oil again, holding the thumb against the upper end. (If an all-levels sample is desired, insert the tube with the upper end open.) When the tube reaches the bottom, remove the thumb and allow the tube to fill. Replace the thumb, withdraw the tube quickly, and transfer the contents to the sample container. Do not allow the hands to come in contact with any part of the sample. Close the sample container; replace and tighten the bung in the drum or barrel. Label the sample container and deliver it to the laboratory. 16.3.2 Obtain samples from cans of 18.9 L (5 gal) capacity or larger in the same manner as for drums and barrels, using a tube of proportionately smaller dimensions. For cans of less than a 18.9-L (5-gal) capacity, use the entire contents as the sample, selecting cans at random as indicated in Table 4 or in accordance with the agreement between the purchaser and the seller. 17. Boring Sampling 17.1 Application--The boring sampling procedure is applicable for sampling waxes and soft solids in barrels, cases, bags, and cakes when they cannot be melted and sampled as liquids. 17.2 Apparatus: 17.2.1 Use a ship auger 2 cm (3/4 in.) in diameter (preferred), similar to that shown in Fig. 10, and of sufficient length to pass through the material to be sampled. 17.2.2 Use clean, wide-mouth metal containers or glass jars with covers for cover sample containers. 17.3 Procedure--Remove the heads or covers of barrels or cases. Open bags and wrappings of cakes. Remove any dirt, sticks, string, or other foreign substances from the surface of the material. Bore three test holes through the body of the material, one at the center, the other two halfway between the center and the edge of the package on the right and left sides, respectively. If any foreign matter is removed from the interior of the material during the boring operation, include it as part of the borings. Put the three sets of borings in

FIG. 10 Ship Auger for Boring Procedure

642

ql~) O 4 0 5 7 .q-

individual sample containers, label, and deliver them to the laboratory. 17.4 Laboratory Inspection--If there are any visible differences in the samples, examine and test each set of borings at the laboratory. Otherwise, combine the three sets of borings into one sample. If subdivision of borings is desired, chill, pulverize (if necessary), mix, and quarter the borings until reduced to the desired amount.

18. Grab Sampling 18.1 ApplicationmThe grab sampling procedure is applicable for sampling all lumpy solids in bins, bunkers, freight cars, barrels, bags, boxes, and conveyors. It is particularly applicable for the collection of green petroleum coke samples from railroad cars and for the preparation of such samples for laboratory analysis. Refer to Practice D 346 when other methods of shipping or handling are used. Petroleum coke may be sampled while being loaded into railroad cars from piles or after being loaded into railroad cars from coking drums. 18.2 Apparatus--A polyethylene pail of approximately 9.5 L (10 qt) capacity shall be used as the sample container. Use a stainless steel or aluminum No. 2 size scoop to fill the container. 18.3 Procedure--Lumpy solids are usually heterogeneous and difficult to sample accurately. It is preferable to take samples during the unloading of cars or during transit; obtain a number of portions at frequent and regular intervals and combine them. 18.3.1 Sampling From Railroad Cars--Use one of the following procedures: 18.3.1.1 Cars Being Loaded from a Pile--Take a full scoop of sample at each of the five sampling points shown in Fig. 11, and deposit in a polyethylene pail. Cover the sample, and deliver it to the laboratory. Each sampling point shall be located equidistant from the sides of the railroad car. 18.3.1.2 After Direct Loading from Coking DrumsuAt any five of the sampling points shown in Fig. 12, take a full scoop of coke from about 30 em (1 ft) below the surface, and deposit it in a polyethylene pail. Cover the sample and deliver it to the laboratory. 18.3.2 Sampling From Conveyors--Take one scoop for each 7 to 9 metric tons (8 to 10 short tons) of coke transported. These samples may be handled separately or composited after all samples representing the lot have been taken. 18.3.3 Sampling From Bags, Barrels, or Boxes:

o--

O0 FIG. 11

•

/.=lengthofcar /

L_

L_

L

L~

L

L ~

L

LL

L

"5

FIG. 12 Location of Sampling Points from Exposed Surface for Rail Cars

18.3.3.1 Obtain portions from a number of packages selected at random as shown in Table 3, or in accordance with the agreement between the purchaser and seller. 18.3.3.2 Carefully mix the grab sample and reduce it in size to a convenient laboratory sample by the quartering procedure described in Practice D 346. Perform the quartering operation on a hard, clean surface, free from cracks, and protected from rain, snow, wind, and sun. Avoid contamination with cinders, sand, chips from the floor, or any other material. Protect the sample from loss or gain of moisture or dust. Mix and spread the sample in a circular layer, and divide it into quadrants. Combine two opposite quadrants to form a representative reduced sample. If this sample is still too large for laboratory purposes, repeat the quartering operation. In this manner, the sample will finally be reduced to a representative, suitable size for laboratory purposes. Label and deliver the sample to the laboratory in a suitable container.

19. Grease Sampling 19.1 Application--This method covers practices for obtaining samples representative of production lots or shipmerits of lubricating greases or of soft waxes or soft bitumens similar to grease in consistency. This procedure is quite general because a wide variety of conditions are often encountered, and the procedure may have to be modified to meet individual specifications. Proceed in accordance with Sections 6 and 7, particularly those paragraphs pertaining to precautions, care and cleanliness, except where they conflict with instructions given in this section. 19.2 Inspection: 19.2.1 If the material is a lubricating grease and inspection is made at the manufacturing plant, take samples from finished shipping containers of each production batch or lot. Never take grease samples directly from grease kettles, cooling pans, tanks, or processing equipment. Do not sample the grease until it has cooled to a temperature not more than 9.4"C (15 *F) above that of the air surrounding the containers and until it has been in the finished containers for at least 12 h. When the containers for a production batch of grease are of different sizes, treat the grease in each size of container as a separate lot. When inspection is made at the place of delivery, obtain a sample from each shipment. If a shipment consists of containers from more than one production batch (lot numbers), sample each batch separately. 19.2.2 If the material being inspected is of grease-like consistency, but is not actually a lubricating grease but some mixture of heavy hydrocarbons, such as microcrystalline

~__~_~__t :~

O0 Location of Sampling Points at Different Levels for Rail Cars

643

fl~) D 4 0 5 7

sufficient quantity to provide a composite sample of the desired quantity (see Table 8). Withdraw portions with a clean scoop, large spoon, or spatula, and place them in a clean container. Very soft, semi-fluid greases may be sampled by dipping with a 0.45 kg (1 lb) can or suitable dipper. If any marked difference in the grease from the various locations of an opened container is found, take two separate samples of about 0.45 kg (1 lb) each, one from the top surface adjacent to the wall and the other from the center of the container, at least 15 cm (6 in.) below the top surface. If any marked variations are noted between different containers of a lot or shipment, take separate samples of about 0.45 (1 lb) from each container. When more than one sample of a batch or shipment is taken because of lack of uniformity, send them to the laboratory as separate samples. 19.4.3 If more than one portion is required to represent a lot or shipment of grease softer than 175 penetration (see Test Method D 217), prepare a composite sample by mixing equal portions thoroughly. Use a large spoon or spatula and a clean container. Avoid vigorous mixing or working of air into the grease. As grease samples become partially "worked" in being removed from containers, the procedure is not suitable for obtaining samples of greases softer than 175 penetration on which unworked penetration is to be determined. For greases having a penetration ofless than 175, cut samples from each container with a knife in the form of blocks about 15 by 15 by 5 em (6 by 6 by 2 in.). If required, make unworked penetration tests on blocks as procured and other inspection tests on grease cut from the blocks.

waxes or soft bitumens, it is permissible to take samples from pans, tanks, or other processing equipment, as well as from containers of the finished product. The grease sampling method shall be applicable to such stocks only if for some reason it is not possible to apply heat and convert the material into a true liquid. 19.3 Sample Size--Select containers at random from each lot or shipment to give the required quantity speeitied in Table 8. 19.4 Procedure." 19.4.1 Examine the opened containers to determine whether the grease is homogeneous, comparing the grease nearest the outer surfaces of the container with that in the center, at least 15 cm (6 in.) below the top surface, for texture and consistency. When more than one container of a lot or shipment is opened, compare the grease in all open containers. 19.4.2 If no marked difference in the grease is found, take one portion from the approximate center and at least 7.5 cm (3 in.) below the surface of each opened container in TABLE 8 Size of Grease Samples Lot or Shipment

Container Tubes or packages, less than 0.45 Kg (1 Ib) 0.45 Kg (1 Ib) cans 2.3 or 4.6 Kg (5 or 10 Ib) cans Larger than 4.6 Kg (10 Ib)

All All All less than 4536 Kg (10 000 Ib)

Larger than 4.6 Kg (10 Ib)

4536 to 22 680 Kg (10 000 to 50 000 Ib)

Larger than 4.6 Kg (10 Ib)

more than 22 680 Kg (50 000 Ib)

Minimum Sample enough units for a 4.4 Kg (2 Ib) sample three cans one can 1 to 1.4 Kg (2 to 3 Ib) from one or more containers 1 to 2.3 Kg (2 to 5 Ib) fl'om two or more contednors 1 to 2.3 Kg (2 to 5 Ib) from three or more contoJners

20. Keywords 20.1 boring sampling; bottle/beaker sampling; core thief spot sampling; dipper sampfing; extended tube sampling; grab sampling; grease sampling; marine custody transfer; sample containers; sample handling; sample labeling; sample mixing; sample shipment; sampling; sampling cage; static sampling; stand pipes;tap sampling; tube sampling

ANNEX

(Mandatory Information) A1. PRECAUTIONARY STATEMENTS A I.I The following substances may be used throughout the course of this standard test method. The precautionary statements should be read prior to use of such substances. A I.I.I Benzene:

A I.I.I.I Keep away from heat, sparks, and open flame. AI.I.I.2 Keep container closed. A I.I.1.3 Use with adequate ventilation. AI.I.I.4 Use fume hood whenever possible. AI.I.I.5 Avoid build-up of vapors and criminate all sources of ignition,especiallynon-explosion proof electrical apparatus and heaters. AI.I.I.6 Avoid prolonged breathing of vapors or spray mist. AI.I.I.7 Avoid contact with skin and eyes. D o not take internally. A 1.1.2 Diluent (Naphtha): 644

Al.I.2.1 Keep away from heat, sparks, and open flame. A 1.1.2.2 Keep container dosed. Al. 1.2.3 Use with adequate ventilation. Avoid build-up of vapors and eliminate all sources of ignition, especially non-explosion proof electrical apparatus and heaters. A1.1.2.4 Avoid prolonged breathing of vapors or spray mist. A1.1.2.5 Avoid prolonged or repeated skin contact. Al.I.3 Flammable Liquid (general): A 1.1.3.1 Keep away from heat, sparks, and open flame. AI. 1.3.2 Keep container dosed. A 1.1.3.3 Use only with adequate ventilation. A1.1.3.4 Avoid prolonged breathing of vapor or spray mist. Al. 1.3.5 Avoid prolonged or repeated contact with skin. A1.1.4 Gasoline (White):

(1~ D 4057 AI. 1.4.6 Avoid prolonged or repeated skin contact. A 1.1.5 Toluene and Xylene: AI. 1.5.1 Warning--Flammable. Vapor harmful. A1.1.5.2 Keep away from heat, sparks, and open flame. AI.1.5.3 Keep container dosed. A1.1.5.4 Use with adequate ventilation. Avoid breathing of vapor or spray mist. A1.1.5.5 Avoid prolonged or repeated contact with skin.

A 1.1.4.1 Harmful if absorbed through skin. A1.1.4.2 Keep away from heat, sparks, and open flame. A1.1.4.3 Keep container closed. Use with adequate ventilation. A1.1.4.4 Avoid build-up of vapors and eliminate all sources of ignition especially non-explosion proof electrical apparatus and heaters. A1.1.4.5 Avoid prolonged breathing of vapor or spray mist.

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted In connection with any item mentioned in this standard. Users of this standard are expre~ly advised that determination of the valMity of any such patent rights, and the risk of Infringement of such rights, are entirely their own responsibility. This standard Is subject to revision at any time by the responsible technical committee and mum be reviewed every five years and ff not revised, either reepproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive Cereful consideration at a meeting of the responsible technical committee, which you may attend, ff you feel that your comments have not received s fair hearing you should make your views known to the ASTM Committee on Standards, 100 Borr Harbor Drive, West Conshohocken, PA 19428.

645

Designation: D 4177 - 95

An American National Standard

Designation: MPMS Chapter 8.2

Standard Practice for Automatic Sampling of Petroleum and Petroleum Products I This standard is issued under the fixed designation D 4177; the number immediately following the designation indicates the year of ori~nal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsllon (0 indicates an editorial change since the last revision or rcapproval.

This standard has been approved for use by agencies of the Department of Defense. Consult the DoD Index of Specifications and Standards for the specific year of issue which has been adopted by the Department of Defense. This practice has been approved by the sponsoring committees and accepted by the cooperating organizations in accordance with established procedures.

1. Scope 1.1 This practice covers information for the design, installation, testing, and operation of automated equipment for the extraction of representative samples of petroleum and petroleum products from a flowing stream and storing them in a sample receiver. If sampling is for the precise determination of volatility, use Practice D 5842 in conjunction with this practice. For sample mixing, refer to Practice D 5854. Petroleum products covered in this practice are considered to be a single phase and exhibit Newtonian characteristics at the point of sampling. 1.2 Applicable Fluids--This practice is applicable to petroleum and petroleum products with vapor pressures at sampling and storage temperatures less than or equal to 101 kPa (14.7 psi). Refer to D 5842 when sampling for Reid vapor pressure (RVP) determination. 1.3 Non-applicable Fluids--Petroleum products whose vapor pressure at sampling and sample storage conditions are above 101 kPa (14.7 psi) and liquified gases (that is, LNG, LPG etc.) are not covered by this practice. 1.3.1 While the procedures covered by this practice will produce a representative sample of the flowing liquid into the sample receiver, specialized sample handling may be necessary to maintain sample integrity of more volatile materials at high temperatures or extended residence time in the receiver. Such handling requirements are not within the scope of this practice. Procedures for sampling these fluids are described in Practice D 1265, Test Method D 1145, and GPA 2166. 1.4 Annex A2 contains theoretical calculations for selecting the sampler location. Annex A3 lists acceptance methodologies for sampling systems and components. Annex A4 gives performance criteria for permanent installations, while Annex A5 has the criteria for portable sampling units. Appendix X1 is a design data sheet for automatic sampling systems; Appendix X2 compares the percent sediment and water to unloading time period. i This practice is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee 1302.02 on Static Petroleum Measurement. Current edition approved Nov. 10, 1995. Published January 1996. Originally published as D 4177 - 82. Last previous edition D 4177 - 82 (1990)*l.

1.5 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. 2. Referenced Documents 2.1 A S T M Standards: D923 Test Method for Sampling Electrical Insulating Liquids 2 D 1145 Test Method for Sampling Natural Gas 3 D 1265 Practice for Sampling Liquified Petroleum (LP) Gases--Manual Method 4 D4057 Manual Sampling of Petroleum and Petroleum Products 5 D4928 Test Method for Water in Crude Oils by Coulometric Karl Fischer Titration 6 D 5842 Practice for Sampling and Handling of Fuels for Volatility Measurements 6 D5854 Practice for Mixing and Handling of Liquid Samples of Petroleum and Petroleum Products 6 2.2 API Standards:7 API Manual of Petroleum Measurement Standards, Chapter 3 API Manual of Petroleum Measurement Standards, Chapter 4 API Manual of Petroleum Measurement Standards, Chapter 5 API Manual of Petroleum Measurement Standards, Chapter 6 API Manual of Petroleum Measurement Standards, Chapter 10 2.3 Gas Processors Association Standard..s GPA 2166 Obtaining Natural Gas Samples for Analysis by Gas Chromatography 2 Annual Book of ASTM Standards, Vol 10.03. 3 Annual Book of ASTM Standards, Vol 05.05. 4 Annual Book of ASTM Standards, Vol 05.01. 5 Annual Book of ASTM Standards, Vol 05.02. 6 Annual Book of ASTM Standards, Vol 05.03. Available from American Petroleum Institute, 1220 L St., NW, Washington, DC 20005. s Available from Gas Processors Assoc., 6526 E. 60th St., Tulsa, OK 14145.

646

~

D 4177

2.4 Institute of Petroleum Standard."9 IP Petroleum Measurement Manual, Part IV, Sampling Section 2, Guide to Automatic Sampling of Liquids from Pipelines, Appendix B, 34th Ed 2.5 Government Standard: ~° CFR 29, Section 11910.1000

3. Terminology 3.1 Description of Terms Specific to This Standard." 3.1.1 automatic sampler, n ~ a device used to extract a representative sample from the liquid flowing in a pipe. 3.1.1.1 Discussion--The automatic sampler usually consists of a probe, a sample extractor, an associated controller, a flow measuring device, and a sample receiver. 3.1.2 automatic sampling system, n ~ a system consisting of stream conditioning, an automatic sampler, and sample mixing and handling. 3.1.3 dissolved water, nDwater in solution in petroleum and petroleum products. 3.1.4 emulsion, n ~ a water in oil mixture, which does not readily separate. 3.1.5 entrained water, n--water suspended in the oil. 3.1.5.1 Discussion--Entrained water includes emulsions but does not include dissolved water. 3.1.6 flow proportional sample, n--flow taken such that the rate is proportional throughout the sampling period to the flow rate of liquid in the pipe. 3.1.7 free water, n--water that exists as a separate phase. 3.1.8 grab, n--the volume of sample extracted from a pipeline by a single actuation of the sample extractor. 3.1.9 homogeneous, adj~when liquid composition is the same at all points in the container, tank, or pipeline cross section. 3.1.10 isokinetic sampling, nDsampling in such a manner that the linear velocity through the opening of the sample probe is equal to the linear velocity in the pipeline at the sampling location and is in the same direction as the bulk of the liquid approaching the sampling probe. 3.1.11 Newtonian fluid, n ~ a liquid whose viscosity is unaffected by the order of magnitude or agitation to which it may be subjected as long as the temperature is constant. 3.1.12 power mixer, n--a device which uses an external source of power to achieve stream conditioning. 3.1.13 primary sample receiver/container, n--a vessel into which all samples are initially collected. 3.1.14 probe, n--the portion of the automatic sampler that extends into the pipe and directs a portion of the fluid to the sample extractor. 3.1.15 profile testing, n--a procedure for simultaneously sampling at several points across the diameter of a pipe to identify the extent of stratification. 3.1.16 representative sample, n--a portion extracted from a total volume that contains the constituents in the same proportions as are present in the total volume. 3.1.17 sample, n--a portion extracted from a total volume that may or may not contain the constituents in the 9 Available from The Institute of Petroleum, 61 New Cavendish St., London WIM BAR, England. ~oAvailable from Supt. of Documents, U,S. Government Printing Office, Washington, DC 20402.

same proportions as are present in that total volume. 3.1.18 sample controller, nma device which governs the operation of the sample extractor. 3.1.19 sample extractor, n n a device which removes a sample (grab) from a pipeline, sample loop, or tank. 3.1.20 sample handling and mixing, n n t h e conditioning, transferring and transporting of a sample. 3.1.21 sample loop (fast loop or slip stream), n m a low volume bypass diverted from the main pipeline. 3.1.22 sampling, nDall the steps required to obtain a sample that is representative of the contents of any pipe, tank, or other vessel and to place that sample into a container from which a representative test specimen can be taken for analysis. 3.1.23 sampling system proving, n--a procedure used to validate an automatic sampling system. 3.1.24 sediment and water (S&W), n--material which coexists with, but is foreign to, a petroleum liquid. 3.1.24.1 DiscussionDS&W may include dissolved water, free water and sediment, and emulsified and entrained water and sediment. 3.1.25 static mixer, n--a device which utilizes the kinetic energy of the flowing fluid to achieve stream conditioning. 3.1.26 stream condition, n--the distribution and dispersion of the pipeline contents, upstream of the sampling location. 3.1.27 stream conditioning, n--the mixing of a flowing stream so that a representative sample can be extracted. 3.1.28 time proportional sample, n ~ a sample composed of equal volume grabs taken from a pipeline at uniform time intervals during the entire transfer. 3.1.29 worst case conditions, n ~ t h e operating conditions for the sampler that represent the most uneven and unstable concentration prot'de at the sampling location.

4. Significance and Use 4.1 Representative samples of petroleum and petroleum products are required for the determination of chemical and physical properties, which are used to establish standard volumes, prices, and compliance with commercial and regulatory specifications.

5. Representative Sampling Criteria 5.1 The following criteria must be satisfied to obtain a representative sample from a flowing stream. 5.1.1 For non-homogeneous mixtures of oil and water, free and entrained water must be uniformly dispersed at the sample point. 5.1.2 Grabs must be extracted and collected in a flow proportional manner that provides a representative sample of the entire parcel volume. 5.1.3 Grabs must be a consistent volume. 5.1.4 The sample must be maintained in the sample receiver without altering the sample composition. Venting of hydrocarbon vapors during receiver filling and storage must be minimized. Samples must be mixed and handled to ensure a representative test specimen is delivered into the analytical apparatus.

6. Automatic Sampling Systems 6.1 An automatic sampling system consists of stream 647

(@) D 4177 Sample grab discharge (in downward sloping line) Flow I

Probe ,r----

~ [ ~

~

Sample receiver (insulate and heat ontrol~er_,~ if necessary) ........

=

Flow

Flow signal

Sample grab discharge (in downward / sloping line) ]l /~---~ Sample receiver ~1 ( ~ "(insulate and heat ~L ~ Controller if necessary)

!

--IN-Sample extractor

Sample extractor and probe indicator Automatic SampIIng-ln-Line

Automatic Sampling With a Fast Loop

NOTEgArrow does not indicatepipingorientation. FIG. 1

Typical Automatic Sampling Systems

conditioning upstream of the sampling location, a device to physically extract a grab from the flowing stream, a flow measurement device for flow proportioning, a means to control the total volume of sample extracted, a sample receiver to collect and store the grabs and, depending on the system, a sample receiver/mixing system. Unique properties of the petroleum or petroleum product(s) being sampled may require the individual components or the entire system be insulated or heated, or both. Appendix X 1 references many of the design consideration that should be taken into account. 6.2 Grabs must be taken in proportion to flow. However, if the flow rate, during the total parcel delivery (week, month, etc.) varies less than +10 % from the average flow rate, a representative sample may be obtained by the time proportional control of the grabs. 6.3 There are two types of automatic sampling systems (see Fig. 1). Both systems can produce representative samples if properly designed and operated. One system locates the extracting device directly in the main line, whereas the other system locates the extracting device in a sample loop. 6.4 In a sample loop type system, a probe is located in the main pipeline and directs a portion of the fluid flow into the sample loop. This probe may be a 90 ° elbow or a 45 ° level facing upstream (see 10.2). The average flow velocity through the sample loop shall be near the maximum average velocity expected in the main pipeline, but not less than 2.5 m/s (8 ft/s). 6.5 The controller which operates the sample extractor in the sample loop receives its flow proportional signal from the flow meter(s) in the main line. For sample loop installations, a flow indicator must also be installed in the sample loop. 6.6 If circulation in the sample loop stops and sampling continues, a non-representative sample will result. A lowflow alarm should be installed to alert the operator of a loss of flow. In no case shall a filter be installed in a sample loop, upstream of the sample extractor, as it may alter the representativeness of the sample.

7. Sampling Frequency 7.1 Guidelines for sampling frequency can be given in 648

terms of "grab per lineal distance of pipeline volume." For marine and pipeline service this minimum guideline can be related to barrels per grab using the following equation: BBL/grab = .0001233 × i)2 or .079548 x d2 (1) where: D -- nominal pipe diameter, mm and d = nominal pipe diameter, in. 7.2 This formula equates to one grab for every 25 lineal metres (approximately 80 ft) of pipeline volume. 7.3 Sampling frequency should be based on maximizing grabs for the available receiver size. Typically, Lease Automatic Custody Transfer (LACT) or Automatic Custody Transfer (ACT) units are paced at one grab per one to ten barrels. 7.4 The optimum sampling frequency is the maximum number of grabs which may be obtained from any parcel operating within the grab frequency and grab volume limitations of the equipment. The completed sample should be of sufficient volume to mix and properly analyze while not over filling the sample receiver.

8. Stream Conditioning 8.1 The sampler probe must be located at a point in the pipe where the flowing stream is properly conditioned. This conditioning may be accomplished with adequate flow velocity through the piping system or mixing elements may be added to supplement mixing provided by the basic piping. Petroleum that contains free or entrained sediment and water (S&W) requires adequate mixing energy to create a homogeneous mixture at the sample point. 8.2 Petroleum products are generally homogeneous and usually require no special stream conditioning. Exceptions to this may occur if free water is present or if a product is exiting a blending system. 8.3 Velocities and Mixing Elements: 8.3.1 Figure 2, based on tests, provides a guideline for minimum velocities versus mixing elements for pipes 50 mm (2 in.) in diameter and larger. Stream conditioning can be accomplished with pressure reducing valves, metering manifolds, lengths of reduced diameter piping, or piping elements

~ Mixing Element Power mixing

D 4177 Minimum Pipeline Velocity. meters per second .91 1.22 1.52 1.83

Piping Horizontal or vertical

0

Static mixing

Vertical

Stratified

Static mixing

Horizontal

Stratified

Not predictable

Piping elements

Vertical

Stratified

Not pred ctab e

Piping elements

Horizontal

Stratified

None

Horizontal or vertical

.305

.61

2.44

Adequate at an}' velocity Not Pred ctable Adequately dispersed Adequately dispersed Adequately dispersed Not predictable

Stratified or not predictable 0 1 2

3 Minimum

FIG. 2

9. Special Considerations for Marine Applications 9.1 When pumping from a shore tank or from a vessel, a significant amount of free water may be transferred during a short period of time (see Appendix X2). This may occur when the pumping rate is low and the oil/water mixture is stratified. The stream conditioning may not be adequate to provide a representative sample. To help minimize this condition, a tank that does not contain free water should be utilized first. Tanks containing free water can be discharged when the pumping rate is normal. 9.2 If the sampler is located some distance from the point of load/discharge, operating procedures should account for the line fill between those two points. 10. Probes 10.1 Probe Location and Installation: 10.1.1 The recommended sampling area is approximately the center one-third of the pipeline cross-section area as shown in Fig. 3. 10.1.2 The probe opening must face upstream and the external body of the probe should be marked with the Typical Receiver Sizes

Lease automaticcustody transfer Pipelines (crude petroleum) Pipelines (products) Portable sampler Tanker loading/unloading

Adequately dispersed

4 5 6 Pipeline Velocity, feet per second

7

S

General Guidelines for Minimum Velocities Versus Mixing Elements

(valves, elbows, tees,piping, or expansion loops). 8.3.2 Where the flow velocity at the automatic sampler probe location fallsbelow the m i n i m u m levels detailed in Table I, additional means will be required to provide adequate stream conditioning such as power mixers or static mixers. The effect of viscosity, density, water content, as well as the relative position of the mixing element(s) and sample probe should also be considered. 8.3.3 Specific calculation procedures for estimating the acceptability of a proposed or existing sampling location are detailed in Annex A2. 8.3.4 Again it should be remembered that petroleum products are assumed to be homogeneous at the point of sampling and require no additional stream conditioning unless specifically sampling for water content, or where the sampler is downstream of a blending manifold.

TABLE 1

2.13

10-60 L (3-15 gal) 20-60 L (5-15 gal) 4-20 L (1-5 gill) 1-20 L (1 qt-5 gal) 20-75 L (5-20 gal)

649

Recommended region for sampling point

FIG. 3

Recommended Sampling Area

direction of flow to verify that the probe is installed correctly. 10.1.3 The probe must be located in a zone where sufficient mixing results in adequate stream conditioning. This zone is generally from 3 to 10 diameters downstream of piping elements, .5 to 4 diameters from static mixers, and 3 to 10 diameters from power mixers. When static or power mixers are used, the manufacturer of the device should be consulted for the probe's optimum location. 10.1.4 The line from the outlet of the extractor to the sample receiver must continuously slope downward from the extractor to the receiver and contain no dead space. 10.1.5 The preferred installation of a combined probeextractor is in the horizontal plane. 10.1.6 If a vertical piping loop is used for stream conditioning, locate the probe in the downflow section of the loop to obtain the benefit of the additional stream conditioning provided by the three 90* elbows. Locate the probe a minimum of three pipe diameters downstream of the top 90* elbow and not closer than one-half pipe diameter upstream of the final exiting elbow (see Fig. 4). 10.1.7 According to tests sponsored by the American Petroleum Institute (API), locating a sample probe downstream of a single 90* bend is not recommended because of inadequate stream conditioning. 10.2 Probe Design." 10.2.1 The mechanical design of the probe should be compatible with the operating conditions of the pipeline and the fluid being sampled. There are three basic designs shown in Fig. 5. Probe openings should be in the center third of the

t!~ D 4177

[ V

MINIMUM

L [/PROBELOCA~ON r-V FIG. 4

General Vertical Piping Loop Configuration

cross sectional area of the pipe. 10.2.2 Probe designs commonly used are described as follows; 10.2.2.1 A closed end probe equipped with an open orifice (see Fig. 5A). 10.2.2.2 A short-radius elbow or pipe bend facing upstream. The end of the probe should be chamfered on the inside diameter to give a sharp entrance (see Fig. 5B). 10.2.2.3 A tube cut at a 45" angle with the angle facing upstream (see Fig. 5C).

11. Automatic Sampling Components l l.l Extractor--An automatic sample extractor is a device that extracts a sample (grab) from the flowing medium. The extractor may or may not be an integral part of the probe. The sample extractor should extract a consistent volume that is repeatable within _+5 % over the range of operating conditions and sampling rates. i 1.2 Controller--A sample controller is a device which governs the operation of the sample extractor. The sample controller should permit the selection of the sampling frequency.

12. Sampler Pacing 12.1 Custody Transfer MetersmCustody transfer meters should be used to pace the sampler where available. When flow is measured by multiple meters, the sampler should be paced by the combined total flow signal. Alternatively, a separate sampler may be installed in each meter run. The sample from each meter run must be considered a part of the total sample and in the same proportion as that meter's volume is to the total volume. 12.2 Special Flow Meters--When custody transfer is by tank measurements, a flow signal must be provided to the sample controller. This signal may be provided by an add-on flow metering device. These devices should have an accuracy of _ 10 % or better, over the total volume of the parcel. 12.3 Time Proportional Sampling--An automatic sampler should preferably operate in proportion to flow. However, sampling in a time proportional mode is acceptable if the flow rate variation is less than _ 10 % of the average rate over the entire parcel.

13. Primary Sample Receivers 13.1 A sample receiver/container is required to hold and maintain the composition of the sample in liquid form. This includes both stationary and portable receivers, either of which may be of variable or fixed volume design. If the loss of vapors will significantly affect the analysis of the sample, a variable volume type receiver should be considered. Mate-

rials of construction should be compatible with the petroleum or petroleum product sampled. 13.2 Stationary Receivers: 13.2.1 General Design FeaturesnThese features may not be applicable to some types of receivers, that is, variable volume receivers. 13.2. l.l Receiver design must allow for preparation of a homogeneous mixture of the sample. 13.2.1.2 The bottom of the receiver must be continuously sloped downward toward the drain to facilitate complete liquid withdrawal. There should be no internal pockets or dead spots. 13.2.1.3 Internal surfaces of the receiver should be designed to minimize corrosion, encrustation, and clingage. 13.2.1.4 A means should be provided to monitor filling of the receiver. If a sight glass is used, it must be easy to clean and not be a water trap. 13.2.1.5 A relief valve should be provided and set at a pressure that does not exceed the design pressure of the receiver. 13.2.1.6 A means to break vacuum should be provided to permit sample withdrawal from the receiver. 13.2.1.7 A pressure gage should be provided. 13.2.1.8 Receivers should be sheltered from adverse ambient conditions when in use. 13.2.1.9 Receivers may need to be heat traced or insulated, or both, when high pour point or high viscosity petroleum or petroleum products are sampled. Alternatively, they may be housed in heated and insulated housing. Exercise caution to ensure added heating does not affect the sample. 13.2.1.10 Use of multiple sample receivers should be considered to allow flexibility in sampling sequential parcels and line displacements. Exercise care in the piping design to prevent contamination between samples of different parcels. See Fig. 6. 13.2.1.11 Receivers should have an inspection cover or closure of sufficient size to facilitate easy inspection and cleaning. 13.2.1.12 Facilities for security sealing should be provided. 13.2.1.13 The system must be capable of completely draining the receiver, mixing pump, and associated piping. 13.2.1.14 The circulating system shall not contain any dead legs. 13.3 Portable Receivers--In addition to considerations outlined in 13.2, portable receivers may include the following additional features: 13.3.1 Light weight, 13.3.2 Quick release connections for easy connection/ disconnect to the probe/extractor and the laboratory mixer (see Fig. 7), and 13.3.3 Carrying handles. 13.4 Receiver SizemThe receiver should be sized to match its intended use and operating conditions. The size of the receiver is determined by the total volume of sample required, the number of grabs required, the volume of each grab and, transportability of the receiver if portable. Typical sample receiver sizes are shown in Table 1.

14. Sample Mixing and Handling 14.1 Sample in the receiver must be properly mixed to

650

~

D 4177

End of probe closed orifice facing upstream ~ T , ~ , o sMtannc~f:r~ltrers u diameter

or tubing 1/4"-2" ~ pipe

~oT~o

45" Bevel receiver r extractor

receiver r extractor

FIG. 5

~/

~

1/4"-2" ¢ pipe or tubing

~=~Toreceiver r extractor

Probe Designs

Probe or extractor

\

•

-

3-way ball valve-hand or motor Note 1 operated from control room ~

Minimize

manifold size and length

Quick ~ ' ~ ~ d i ~ n e c t

Solenoid E1 valves

(~

Probe or extractor

~"

Note

Installation Showing Portable Receivers

Sin.gle receiver

Multiple receivers

NOTEn6,4 or 9.5 mm (1/4 or a/a In.) tubing, as short as possible and sloping continuously toward the sample receiver, should be used. 9.5 mm (~e in.) tubing should be used where long sampling lines cannot be avoided or in crude oil service. Heat trace and insulate these lines when necessary. FIG. 6 Receiver(s) Installation

ensure a homogenous sample. Transfer of samples from the receiver to another container or the analytical glassware in which they will be analyzed requires special care to maintain their representative nature. See Practice D 5854 for detailed procedures.

NOTE 1--6.4 or 9.5 mm (=/s in.) tubing, as short as possible and sloping continuously toward the sample receiver should be used. Thr~¢~ghths inch tubing should be considered where long sampling lines cannot be avoided or the crude oil is viscous. Heat trace and Insulate these lines when necessary. NOTE 2--Sample should flow into a cennectidn at the top of the container. In warm climates, a sun shield should be provided to avoid excessive temperature changes in sample receivers. NOTE 3~ln warm climates, a sun shield should be provided to avoid excessive temperature changes In sample revivers. NOTE 4--In cold climates, consider placing sample receivers in a heated housing or heat trace and Insulate the receivers and sample lines. FIG, 7 Portable Receiver(s) Installation

controller must be able to record total number of grabs and total volume. 15.2.3 Piping arrangement at the ship's manifold will often distort the flow profile. The flow sensor, when operated under the piping and flow conditions at the ship's manifold, must meet the accuracy criteria in 12.2. 15.2.4 Stream conditioning is accomplished by velocity of the fluid and the piping elements ahead of the probe. The number of hoses, arms, and lines in service at any one time may need to be limited to maintain sufficiently high velocity. 15.2.5 The controller may be placed on the ship's deck, which is usually classified as a hazardous zoned area. If the controller is electronic, it should meet the requirements of the hazardous area. 15.2.6 Air supply must meet the requirements of the equipment. 15.2.7 For high pour or viscous fluids, particularly in cold climates, the line from the extractor to the receiver may require a thermally insulated high pressure hose or tubing. The receiver should be placed as close to the extractor as

15. Portable Samplers 15.1 A typical application of a portable sampling system is on board a marine vessel. There are also occasional applications on shore. The same criteria for representative sampling applies to both portable and stationary sampling systems. Exercise caution when using portable samplers on marine vessels due to the difficulty in verifying stream conditioning during actual operations. An example of a marine application is shown in Fig. 8. 15.2 Design Features--Special features and installation requirements for a portable sampler are: 15.2.1 A spool assembly fitted with a sample probe/ extractor and flow sensor is inserted between the ship's manifold and each loading/unloading arm or hose. If the grab size of each sampler is equal, a common receiver can be used. 15.2.2 A controller is required for each extractor. The 651

(~ D 4177

- -

Smnpl* Pmb*

Contrgl Unit

FIG. 8

Typical Portable Marine Installation

possible to minimize the hose length. The hose or tubing should have an internal diameter of 9.5 mm (% in.) or more and slope continuously downward from the extractor to the receiver. The line from the extractor to the receiver may have to be heat traced. 15.2.8 Filling of receivers should be monitored to ensure that each sampler is operating properly. Frequent visual inspection, level indicators, and weighing have proven to be acceptable monitoring methods. 15.2.9 The portable sampler is used intermittently; therefore the sample probe, extractor, and flow sensor should be cleaned after every use to prevent plugging. 15.2. I0 All components and installation must meet applicable regulations, that is, U.S. Coast Guard regulations. 15.3 Operating Considerations--The portable sampler operator must maintain operating conditions which provide adequate mixing and produce a representative sample. Performance criteria is given in Annex A5. To meet the criteria requires cooperation of the vessel crew and shore personnel. Special operating requirements are: 15.3.1 The portable sampler operator should keep the flow rate at each flow sensing device within its design range by limiting the number of loading lines or hoses in service during periods of low flow rates, for example, start-up, topping off, stripping, etc. 15.3.2 For discharge operations, the vessel compartment discharge sequence must be controlled so that the amount of free water being discharged during the start-up operation is less than 10 % of the total amount of water in the cargo. 15.3.3 For loadings, a shore tank with no free water is preferred for the initial pumping. Water drawing the tank or pumping a small portion of the tank to another shore tank prior to the opening tank gage, or both, are suggested.

16. Acceptance Tests 16.1 Testing is recommended to confirm that a sampling system is performing accurately. Annex A3 outlines methods for testing samplers that are used for the collection of S&W 652

or free water samples. The test methods fall in two general categories; Total System Testing and Component Testing. 16.2 Total System Testing--This test method is a volume balance test where tests are conducted for known amounts of water. It is designed to test the total system including the laboratory handling and mixing of sample. Two procedures are outlined. One involves only the sampler under test, the other utilizes an additional sampler to measure the baseline water. 16.3 Component Testing--This test method involves testing individually the components that comprise a sampling system. Where applicable, some of the component tests may be conducted prior to installation of the total system. Components to be tested include: 16.3. l Probe/extractor, 16.3.2 Profile (for stream conditioning), 16.3.3 Special flow meter, and 16.3.4 Primary sample receiver and mixer. 16.3.5 If a system design has been proven by testing, subsequent systems of the same design (for example, LACT Units), including piping configuration and operated under the same or less criterial conditions (that is, higher flow rate, higher viscosity, lower water content, etc.) need not be tested. Once a system or system design has been proven, the following checks can be used to confirm system reliability: Component

Check

Stream conditioning

Flow rate or pressure drop if equipped with power or static mixer. Profde test for systems with only piping elements. Compare recorded batch volume to known. Compare actual sample volume to expected volume. Compare actual sample volume to expected volume. Compare actual grab size to expected grab size.

Pacing device Extractor

16.3.6 Portable sampling systems can be tested by the component testing method except for proper stream conditioning. To compensate for this, the performance test for each operation has been designed to evaluate the operation of the sampler. This is shown in Annex A5. 16.4 Requirements for Acceptability--Testing by either the component or total system method requires that two out of three consecutive sets of test data repeat within the limits shown in Annex A3.

17. Operational Performance Checks/Reports 17.1 Monitoring of sampler performance is a necessary part of every sampling operation. Monitoring is required to make sure that the sample extractor is extracting a uniform grab in a flow proportional manner. This is normally accomplished by assessing the sample volume collected to ensure that it meets expectations for the equipment and transfer volume involved. 17.2 Several procedures may be used to accomplish this requirement, that is, sight glasses, gages, or weigh cells. Selection of a procedure should be based on (1) volume of transfer, (2) type of installation, (3) time interval of transfer, (4) whether the sampling facility is manned, (5) receiver type, (6) purpose of the sample, and (7) equipment used. 17.3 For LACT and ACT units, monitoring may consist of comparison between sample volume collected and expected sample volume. For very large transfers including marine transferee, more information may be desired as outlined in Annexes A4 and A5.

(~

I

8/~ELINE

SAMPLE

D 4177

I [

WATERINJECTION I AND

[

,Es, SAM,~E

i

i

I

I

~.

I

I.

I

I

I

SPREADING

I

BASELINESAMPLE I

I

Time NOTEmTimes are calculated based on minimum oil flow rate and the distance between the injection and the sample point. FIG. 9

Sequence of Acceptance Teat Activities

18. Keywords

isokinetic sampling; mixing elements; portable samplers; primary sample receiver; probe; representative sampling; representative sampling criteria; sampling handling; sample loop; sample mixing; stream conditioning

18.1 acceptance tests; automatic petroleum sampling; controllers; extractor; intermediate sampling receiver;

ANNEX (Mandatory Information)

AI. PRECAUTIONARY INFORMATION

A 1.1 Physical Characteristics and Fire Considerations: A 1.1.1 Personnel involved in the handling of petroleumrelated substances (and other chemical materials) should be familiar with their physical and chemical characteristics, including potential for fire, explosion, and reactivity, and appropriate emergency procedures. These procedures should comply with the individual company's safe operating practices and local, state, and federal regulations, including those covering the use of proper protective clothing and equipment. Personnel should be alert to avoid potential sources of ignition and should keep the materials' containers closed when not in use. Al.I.2 API Publication 2217 and Publication 20265 and any applicable regulations should be consulted when sampiing requires entry to confined spaces. A1.1.3 INFORMATION REGARDING PARTICULAR MATERIALS AND CONDITIONS SHOULD BE OBTAINED FROM THE EMPLOYER, THE MANUFACTURER OR SUPPLIER OF THAT MATERIAL OR THE MATERIAL SAFETY DATA SHEET. A1.2 Safety and Health Consideration: A 1.2.1 General." AI.2. I. 1 Potential health effects can result from exposure to any chemical and are dependent on the toxicity of the chemical, concentration, and length of the exposure. Everyone should minimize his or her exposure to work place

653

chemicals. The following general precautions are suggested: (a) Minimize skin and eye contact and breathing of vapors. (b) Keep chemicals away from the mouth; they can be harmful or fatal if swallowed or aspirated. (c) Keep containers closed when not in use. (d) Keep work areas as clean as possible and well ventilated. (e) Clean spills promptly and in accordance with pertinent safety, health, and environmental regulations. (]) Observe established exposure limits and use proper protective clothing and equipment. NOTE Al.l--Information on exposure limits can be found by consulting the most recent editions of the Occupational Safety and Health Standards, 29 Code of Federal RegulationsSections 11910.1000 and followingand the ACGIH publication "Threshold Limit Values for Chemical Substancesand PhysicalAgents in the Work Environment."~' AI.2.1.2 INFORMATION CONCERNING SAFETY AND HEALTH RISKS AND PROPER PRECAUTIONS WITH RESPECT TO PARTICULAR MATERIALS AND CONDITIONS SHOULD BE OBTAINED FROM THE EMPLOYER, THE MANUFACTURER OR THE MATERIAL SAFETY DATA SHEET. , t AvailablefromAmericanConferenceof GovernmentIndustrialHygienists, (ACGIH),Bldg. D-7, 6500 OlenwayAve., Cincinnati, OH 45211-4438.

1]~) D 4177 A2. T H E O R E T I C A L CALCULATIONS FOR SELECTING T H E S A M P L E R PROBE LOCATION A2.1 Introduction: A2.1.1 This annex describes calculation procedures for estimating the dispersion of water-in-oil at a sampling location. These procedures have a very simple theoretical base with many of the equations not being strictly applicable; therefore, they should be used with extreme caution in any practical application. A conservative approach is strongly recommended when estimating the acceptable limits for adequate dispersion (steam conditioning).

defined in Eq 2. Table A2.2 presents the relationship of C1/C2 with G. c = ~

NOTE A2.l--From IP Petroleum Measurement Manual, Part IV Sampling: A2.1.2 The equations contained in this annex have been shown to be valid for a large number of field data. The range of the field data covered the following correlating parameters: Relative density Pipe diameter Viscosity Flowing velocity Water concentration

(3)

where: AP = the pressure drop across the piping element, V --the flow rate at the pipe section in which energy is dissipated, and

NOT~ A 2 . 2 - - U s e caution when extrapolating outside o f these ranges.

A2.1.3 When evaluating if dispersion is adequate or not in a given system, using the worst case conditions is recommended. A2.1.4 When calculating the dispersion rate E in A2.3, it should be noted that dispersion energies of different piping elements are not additive in regard to dispersion, that is, when a series of elements is present, the element that should be considered is the one that dissipates energy the most. A2.1.5 As an aid in determining the element most likely to provide adequate dispersion, Fig. A2.2 has been developed. When using Fig. A2.2, it is important to consider it as a guide only and that particular attention should be paid to the notes. Fig. A2.2 does not preclude the need for a more detailed analysis of these elements, within a given system, shown by the table to be the most effective. A2.2 Symbols--The symbols used in Annex A2 are presented in Table A2.1. A2.3 Dispersion Factors: A2.3.1 As a measure of dispersion, the ratio of water concentration at the top of a horizontal pipe C~ to that at the bottom C2 is used. A CJC2 ratio of 0.9 to 1.0 indicates very good dispersion while a ratio of 0.4 or smaller indicates poor dispersion with a high potential for water stratification. Calculations giving ratios less than 0.7 should not be considered reliable as coalescence of water droplets invalidates the prediction technique. A2.3.2 The degree of dispersion in horizontal pipes can be estimated by: exp ( - ~ )

A2.3.4 It is important to note that the uncertainty of the calculations is such that errors in G of more than 20 % may result at low values of G. For this reason, it is recommended that no reliance be placed upon calculated G values of less than 3 and that additional energy dissipation calculated G value. A2.4 Determination of Energy Dissipation." A2.4.1 Two different techniques are given for determining the rate of energy dissipation. A2.4.2 Method A uses the relationship in Eq 3.

APV E = ~pp

.8927-.8550 (27"-34" API) 40 era-130 em (16 in.-52 in.) 6-25 c.St at 40"C >0-3.7 m/s (>0-12 if/s) <5 %

C1

(2)

w

TABLE A2.1

Symbols Used in Annex A2

NOTE 1--1 Pa = 10 -s bar NOTS 2--1 m=/s = 10e cSt = 10e mm=/s NOTE 3--1 N/m = 10a dyn/cm Symbol

Term

water concentration (water/oil ratio)

C D d E Eo E, G K n Ap Q r V VI W AX $ 3'

pipe diameter droplet diameter rate of energy dissipation energy dissipation in straight pipe required energy dissipation parameter, defined In A2.3.3 resistance coefficient number of bends pressure drop volumetric flow rats bend radius flow velocity flow nozzle exit velocity settling rate of water droplets dissipation distance parameter, defined in A2.4.3 ratio between small and large diameters eddy diffuslvity turn angle kinematic viscosity surface tension crude oil density water density flow nozzle diameter

# v ¢ p Pa ¢

(1)

TABLE A2.2

C2

G

where:

C~/Cz = the ratio of water concentration at the top (C~) to that at the bottom (C2), = the settling rate of the water droplets, and ~/D = the turbulence characteristic, where ~ is the eddy diffusivity and D the pipe diameter. A2.3.3 An alternative measure of dispersion, G, can be W

654

Dispersion Factors C1/C=

Units dimensionless m m W/kg W/kg W/kg dimensionless dimensionless dimensionless Pa(1) mS/s m m/s m/s m/s m dimensionless dimensionless m2/s

degrees m=/s (2) N/m (3) kg/m 3 kg/m s m

C=/CI

10

0.90

1.11

8

0.88

1.14

6 4 3 2 1.5 1

0.85 0.78 0.71 0.61 0.51 0.37

1.18 1.28 1.41 1.64 1.96 2,70

(~ D 4177 TABLE A2.3

Suggested Resistance Coefficients, K

NOTE~3' is the small diameter/large diameterand K is based on the velocity in the smaller pipe. Contraction

K = 0.5 (1 - ~,2)

(0~Ks0.5)

Enlargement

K = (1 -,f4~,2)2

(0~Ks0.5)

Circular mitre bends

K = K K K K

Swing check valve Angle valve Globe valve Gate valve

= 1.2 (1 - cos O) where 0 rum angle = 2 == 2 ,= 6 = 0.15

(0sK~I.2)

d = O.3625 (~)°'6 E -°.4

(8)

where: a - t h e droplet surface tension between water and oil measured in N/m. All formulas and examples in this Annex A2 assume a = 0.025 N/m. A2.7.2 Interfacial tension values may be significantly affected by additives and contaminants. If it is known that the value is other than 0.025 N/m, the water droplet settling velocity W, given in A2.8, should be modified by multiplying by Eq 9. 0.--~]

AX

a characteristic length which represents the distance in which energy has been dissipated. In most cases AX is not known with any confidence. Wherever possible, the value to be used should be supported by experimental data. NOTE A2.3--If AX is not known, a substitute value of AX = 10D may be used as a very rough approximation for devices of low mixing efficiency such as those in Table A2.3. For specially designed high efficiency static mixers the value AX will be small and should be obtained from the designer. NOTE A2.4--1f AP is not known, calculateit from Eq 4. =

KpPa 2

AP = ~

(4)

where: K = the resistance coefficient of the piping element under consideration. Suggested values of K for different piping elements are given in Table A2.3. A2.4.3 Method B uses the relationship E ---/3Eo, where/3 is a characteristic parameter of a mixing element and Eo is the rate of energy dissipation in a straight pipe. Eo is calculated from Eq 5. Eo = 0.005u0.25D-I.25 V2.75

A2.8 Water Droplet Settling Velocity: A2.8.1 The determination of either of the dispersion factors requires a knowledge of the water droplet settling rate, W. This can be calculated using the relationship in Eq 10. W = 855(Pd -- P ) E " ° ' s

where: Pa = the water density. For salt water (from wells or tankers) a suggested value is 1025 Kg/m 3 if the actual one is not available. A2.8.2 If the mean water concentration is higher than 5 %, multiply W b y 1.2. A2.9 Turbulence Characteristic: A2.9.1 Determination of either of the dispersion factors requires the turbulence characteristics ~/D to be evaluated using Eq 11. L = 6.313 x 10-3V°'S75D-°'I25v 0"125 D

-

-

sequence:

A2.10.1 Determine the desired profile concentration ratio

Ct/C2 and, using Table A2.2, the corresponding value of G. A2.10.2 Determine, using Fig. A2.1, which pipeline fittings within 30D upstream of the sampler are most likely to provide adequate dispersion. A2.10.3 Estimate the energy available from each of the most likely fittings using either of the methods described in A2.4. A2.10.4 Calculate the value of G from the highest value of available energy obtained in step (c) using the formulas presented in A2.3, A2.8, and A2.9. A2.10.5 Obtain the Ct/C2 ratio from Table A2.2. A2.10.6 Check that the calculated CJC2 (or G) value is higher than the desired value obtained in A2.10.1. If it is, the sampler location should prove suitable for the application. If not, remedial action should be taken.

(7)

.y4

A2.6.1 Enlargement effects can be calculated with Eq 7. A2.7 Mean Water Droplet Diameter: A2.7.1 The mean water droplet diameter d may be estimated using Eq 8. TABLE A2.4 r/d n n n n n

= = = = =

1 2 3 4 5

(1 1)

A2.10 Verification of an Existing Sampler Location--It is important to select the worst case conditions in the following

(5)

5(! -- ,)12)2 =

(10)

up 2.2

where: v is given in mm2/s (cSt). A2.4.4 Suggested values of/3 and tentative relationships for E (other than E =/3Eo) are given in Tables A2.4 and A2.5 respectively. A2.5 Contraction: /~ = 2.5(1 - 3,2) (6) A2.5. l Contraction effects can be calculated with Eq 6. A2.6 Enlargement: /~

(9)

Dissipation Energy Factors (B) (1, 2)

1

1.5

2

3

4

5

10

1.27 1.55 1.90 2.20 2.60

1.25 1.50 1.80 2.10 2.40

1.23 1.48 1.75 2.00 2.30

1.22 1.45 1.70 1.93 2.20

1.18 1.38 1.56 1.72 1.90

1,15 1.30 1.44 1.56 1.70

1.07 1,13 1.16 1.23 1.28

655

(~

D 4177 4630 [Pa - p],.2~ E, = o~.--S L--7~J

TABLE A2.5 DissipationEnergyRelationships Centrifugal pump

E = 0.125

A2.11.5 Select from Fig. A2.1 the available piping elements most likely to provide adequate energy dissipation. A2.11.6 Calculate the dissipation energy E for the selected piping elements using either of the methods described in A2.4. A2.11.7 Compare Er with E to determine if an acceptable profile can be achieved. If for any piping element E > E,, then a satisfactory profile can be achieved using that element. If E < Er for all piping elements, then additional dissipation energy must be provided. This can be done by reducing the pipe diameter (a length > 10D is recommended) by introducing an additional piping element or by incorporating a static or dynamic mixer. A2.11.8 If the flow rate has been increased by reducing the pipe diameter, repeat steps A2.10.8 to A2.10.13. A2.11.9 If a new piping element has been introduced into the system without changing the flow rate, check, using step A2.11.6, that its dissipation energy is larger than the best so far achieved and, if so, proceed to step A2.11.7. A2.11.10 If a static or dynamic mixer is considered, then the manufacturer should be consulted as to its design and application. A2.12 Examples--Verification of an existing sampler location:

pO3

nPV

Throttling valve

E =

Flow nozzle

E = 0.022 vF

20pD

A2.11 Selection of a Suitable Sampler Location--It is again very important to select the worst case and continuing the above sequence. A2.11.1 Determine if the desired profile concentration ratio C,/Cz and, using Table A2.2, the corresponding value of G. A2.l 1.2 Determine the turbulence characteristic 4D as described in A2.9. A2.11.3 Calculate the water droplet settling rate using Eq 12.

W= '/----D-D (12) G A2.11.4 Determine the energy required to produce the desired profile concentration ratio using the formula presented in A2.8 re-written in the form of Eq 13. PUMP

a P

ORIFICE

r = d/D =

(13)

(bar)

0.9

~NLARGEMENT

o;

-x

¥ = d/D =

x

^

0_61

xl

^

VALVE

A P

(bar)

X --

-^

04 --X

1 ~HROTTLING

~.

051 XI 2 -- - - X - -

.,~

03

--.-.

02

I

~X-

4

618

12 x20

--X-

X i -X--X -

30 50

--X-- X ,

X

]LOBE V A L V E ~WING C H E C K O R A N G L E

VALVE

2IRCULAR M I T R E ]END

0

~ONTRACTION

y = d/D

3ENDS

(S-OFF)

r/D

3ENDS

(4-OFF)

r/D

3ENDS

(3-OFF)

r/D

3ENDS

(2-OFF)

r/D

3ENDS

(1-OFF)

r/D

60 90 --x- - x

45 - - x w

(deg)

0.8 0.70.5 x - - ~ --x 10

0.1 --x

4

x

1

x - - ~

10

4

X --X 10 X

1

--X 1 X

10

1

X--X 10

1

X~

;TRAIGHT P I P E ;ATE V A L V E R E S I S T A N C E C O E F F I C I E N T (K) CHARACTERISTIC (~) PARAMETER OF MIXING ELEMENT

O. 1.0

0~5 2,5

1.0 5.0

2.0 i0.0

4.0 20.0

10.0 50.0

20,0 40.0 i00.0 i00.0 2 0 0 . 0 500.0

200.0 i000.0

400.0 2000.0

i000.0 5000.0

NOTE 1 - - T h e table has been compiled assuming the same pipeline diameter downstream of any device. If the downstream diameter of any two devices is not identical, comparisons using Fig. A2.1 cannot be performed. NOTE 2 - - I t is not intended that Fig. A2.1 be used to ascertain/~ or K values but only to provide s comparison of the likely mixing effects of devices. NOTE 3 - - F o r centrifugal pumps and throttling valves, the dissipation energies, which are defined without the use of ~' values (see Table A2.1), the comparison has been done using an assumed/~ equal to E/Eo and the following typical vaiues--D = 0.4 m; v = 16 cSt; p == 900 kg/mS; V = 5.6 m/s. FIG. A2.1 C o m p a r i s o n of Mixing Devices

656

(~) D 4177 A2.12.1.6 The calculated value of Cl/C2 is greater than the required value, and therefore, adequate conditions for sampling exist. A2.12.1.7 Using Method B, A2.4:

A2.12.1 Using the procedure o f A2.10, for an installation in a 500 m m pipe where the most severe operating conditions are represented by: v = 2 m/s -- 850 kg/m 3 ~, 8 cSt

p

g = BEo m/kg 5(1 - 3,2)2 /~ = = 45 (Table A2.3) 3,4

=

Pa =

1025 kg/m 3

A2.12.1.1 The desired C~/C2 ratio is 0.9, from Table A2.2, G = 10. A2.12.1.2 The pipeline fittings within 30D upstream o f the sampler are a globe valve, an enlargement with diameter ratio, -y = 0.5 and two 90* bends. Then, from Fig. A2.1 the globe valve or the enlargement is clearly most likely to provide adequate dispersion. A2.12.1.3 The energy available m a y be calculated using either Method A or B o f A2.4. However, only K values are given for the globe valve, therefore, these must be used to compare the likely mixing effects o f the globe valve and the enlargement. Globe valve K = 6 (1 Enlargement K = ~

-

E 0 = 0 . 0 0 5 u ° ' 2 5 D - I ' 2 5 V TM

.'.E = 45 x 0.005 x 8TM x ~

APV ta.xp W/kg

X 2 TM

(20)

G = ~/D (Table A2.2) W

(2)

¢/D --- 16.37 × 10-3 m/s

(21)

as calculated for Method A: w

=

855(aa -

p)

Vp2.2

= 855(1025 - 850) 8 x 8502.2 = 1.59 x

E -°'s m/s x

(10)

1 6.0545 °'s

~

(22)

10-3 m/s

.'. G = 16.37 x 10-3 = 10.29 1.59 x 10-3

(3)

= "T'SS.._

(19)

= 6.0545 W/kg

= 9 (Table A2.3) 3,'* The enlargement has the higher K value and should be used in the following calculations. A2.4 may be used for the rest of the calculation. (a) Using M e t h o d A, A2.4: E

(18)

A2.12.1.8

(Table A2.3)

3'2)2

1

(17)

(23)

A2.12.1.9 Follow A2.12.1.5 and A2.1.1.6 as for Method

or as:

A. AP = Ko:V 2 W/kg 2

A2.12.2 Selection of a Suitable Sampler Location--Using the procedure o f A2.11: A2.12.2.1 The proposed pipeline configuration consists o f a 600 m m line enlarging to 800 m m followed by a line of three 90* bends each with an r to D ratio of 1 and finally a throttling valve with the differential pressure o f one bar. The most severe operating conditions are represented by the following conditions: V = 1.5 m/s p ----- 820 kg/m 3 v --- 7 cSt Pd - 1025 kg/m 3

(4)

then: E

=

_.._ 2AX

W/kg

(12)

and using AX = 10D E=

9

x

23

2 x 10 x 0.5

= 7 . 2 W/kg

(13)

A2.12.1.4 G = e/O

(2)

w

D

= 6.313

X 10-3V°'375D-0"I2Sv0'12s m / s

W=

855(pa - p) E -°-s m/s vp2.2

"'" D ~ = 6.313 X l0 -3 X 2°.s75 X ~ .1

A2.12.2.2 The desired CI/C2 ratio is 0.9; then, from Table B.2, G = 10. A2.12.2.3 The turbulence characteristic from B.6 is: e/D = 6.313 x 10-3V°'S75D-°'I25~0"125 m/s (13)

(11) (10)

X 8o.i 2

= 6.313 X 10 -3 X 1.50.875 X ~

(14)

1

X 70'125

(24)

---- 11.81 X 10 -3 m / s

= 16.37 × 10-3 m/s

A2.12.2.4 The water droplet settling velocity is:

and W = 855(1025 - 850) x 8 X 8502.2 = 1.38 X

1 °---''~ 7.2

W = e/D = 11.81 X 10-3 = 1.18 X 10-3 m/s G 10

(15)

A2.12.2.5 The energy dissipation rate required per Eq 26

10-3 m/s

16.37 x 10-3 .'.G = 1.38 x 10-3 = 11.83

(25)

is: (16)

4630 Ip_a_z._p.11.25 Er = ~ I. v W J

A2.12.1.5 From Table A2.2 the Ct/C2 ratio is greater than 0.9. 657

(26)

(~ D 4177 4630 {

1025 - 820 ,~L25

820 TM \7 X 1.18 X 10-3]

-- = 6.313 x 10-3 x 2.67°'s75 x - -

(27)

D

A2.12.2.10

A2.12.2.6 From Fig. A2.1 the throttling valve is clearly the element most likely to provide sufficient energy dissipation. A2.12.2.7 Method B is the only one to provide an energy dissipation formula for a throttling valve; see Table A2.5.

W= m=e/D 20.25 x 10-5 = 2.02 × 10-3 m/s G 10 A2.12.2.11 4630 [ 1025 - 820 ]t.25 E, = 8202.75 ~7 X 2.02 x 10-3J W/kg = 7.13 W/kg A2.12.2.12 Unchanged from previous calculation. A2.12.2.13 APV E -- ~ Wlkg

(28)

I x 10 5 X 1.5

- 20 x 820 x 0.8 [1 bar = 105 Pascal]

(30)

= 20.25 x 10-3 m/s

= 13.99 W/kg

APV .'. E = 2-~pD W/kg

x 70.125 m/s

0 . 6 °'125

(29)

= 11.43 W/kg A2.12.2.8 The energy dissipation rate E provided by the throttling valve is less than required Er. Therefore, a G value of 10 has not been achieved and sampling from this location is unlikely to prove adequate. If the enlargement from 600 to 800 mm is moved downstream of the throttling valve and sampling location, then the following recalculation applies with D = 0.6 m and V-- 2.67 m/s: A2.12.2.9

-

105 x 2.67 20 x 820 x 0.6

(31)

(32)

(33) (34)

= 27.10 W/kg A2.12.2.14 The energy dissipation rate provided by the throttling valve located in the smaller diameter pipe is more than sufficient to give a G value of 10. Adequate sampling should therefore be possible.

A3. ACCEPTANCE M E T H O D O L O G I E S FOR SAMPLING SYSTEMS AND C O M P O N E N T S A3.1 Descriptions of Terms Specific to This Standard-The following definitions are included as an aid in using Tables A3.1 and A3.2 for profile test data and point averages and deviation: A3.1.1 minimum flow rate, n - - t h e lowest operating flow rate, excluding those rates which occur infrequently (that is, 1 of 10 cargoes) or for short time periods (less than 5 min). A3.1.2 overall profile average, n - - t h e average of all point averages. A3.1.3 point, n--a single sample in a profile. A3.1.4 point average, n - - t h e average of the same point from all profiles (excluding profiles with less than 1.0 % water). A3.1.5 profile, n--multi-point samples taken simultaneously across a diameter of the pipe. A3.2 Acceptance Testing--Water Injection Volume Bal-

TABLE A3.1 A l l o w a b l e Deviations for the Single and Dual Sa mp l e r W a t e r Injection A c c e p t a n c e Tests ( V o l u m e %) NOTE 1--The reference to tanks or meters refers to the method used to determine the volume of crude ell or petroleum In the test. NOTE 2--Deviatldns shown reflect use of the Karl Fischer test method described in D 4928 for water. NOTE 3--interpolation is acceptable for water concentrations between values shown in the table. For example, ff the total water Is 2.25 ',~ the allowable deviation using tank gages would be 0.175 ~ and 0.135 ~ if using meters. NOTE 4~This table is based, in part, on statistical analysis of a data base consisting of 36 test rune from 19 installations. Due to the number of data, it was not possible to create separate data bases for analysis by the volume determination method, that Is, by tank or meter. Therefore, it was necessary to treat the data as a whole for analysis. The data base is valid for the water range 0.5 ~oto 2.0 %. NOTE 5--The reprodudblllty standard deviation calculated for the data, at a 95 ~oconfidence level, has boon used for the meter values shown in the table in the water range 0.5 to 2.0 ~o. Assigning these values to the meter is based on a model that was developed to predict standard deviations for volume determinations by tanks and meters. Values shown in the table for the tank, in the range 0.5 % to 2.0 ~, were obtained by adding 0.04 ~ to the meter values in this water range. The value of 0.04 ~ was derived from the aforementioned model as the average bias between tank and meter volume determinations. NOTE 6--AS there Is insufficient test data for water levels over 2.0 $, values shown In the table above 2.0 '$ have been extrapolated on a straight line basis using the data in the 0.5 ~o to 2.0 • range. NOTE 7--In order to develop a broader data base, owners of systems are encouraged to forward a copy of test data using test data sheets as shown in Annex A6 to the American Petroleum Institute, Industry Services Department, 1220 L Street, N.W., Washington, DC 20005.

ance Tests: A3.2.1 This annex describes three test methods shown to be acceptable in proving the performance of pipeline and marine automatic pipeline sampling systems, that is, single sampler, dual sampler and component testing. These methods have equal validity and the order listed should not be construed as one method having preference over another. Once a system design has been proven, subsequent systems of the same design (for example, LACT units), including piping configuration and similar service need not be tested. Refer to Section 16 for verification of systems of the same design. A3.2.2 The following procedures are presented for the testing of systems to identify water in petroleum. The same approach may be modified to apply to petroleum blending systems. A3.2.3 The single and dual sampler tests are designed to

Total Water ON test) 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0

658

AllowableDeviations Using Tank Gages

Using Meters

0.13 0.15 0.16 0.17 0.18 0.19 O,20 0.21 0.22 0.23

0.09 0.11 0.12 0.13 0.14 0.15 0.16 0.17 0.18 0.19

(~ D 4177 meters should be installed and proven in accordance with API MPMS Chapters 4, 5 and 6. Oil volumes should be measured by tank gage or meter in accordance with applicable API MPMS Chapters 3, 4, 5 and 6 guidelines. A3.3.3 Locate the water injection point upstream of the elements expected to produce the stream conditioning for the sampling system. Be aware of potential traps in the piping which may prevent all of the injected water from passing the sample point. Exercise care to ensure that the location and manner in which water is injected does not contribute additional mixing energy at the point of sampling which would distort the test results. Equipment or facilities used to inject water should be in accordance with local safety practices. A3.3.4 Review the normal operating conditions of the pipeline in terms of flow rates and crude types. Select the most common, worst case conditions to test the sampling system. The worse case is commonly the lowest normal flow rate and the highest API gravity crude normally received or delivered. A3.3.5 In the case of the single sampler acceptance test, a source of constant water content for oil must be identified for the test. If possible, it is suggested that this oil be isolated as changes in the baseline water content can produce inconclusive test results. A3.4 Single Sampler--Acceptance Test: A3.4.1 Purge the system at a sufficiently high flow rate to displace free water which may be laying in the pipeline system upstream of the automatic sampling system (refer to Fig. A3.1). A3.4.2 Establish the flow rate for the test. A3.4.3 Collect the first baseline sample(s). A baseline sample may be a composite sample collected in a separate sample receiver or several spot samples collected at intervals directly from the sample extractor. A3.4.4 Record the initial oil volume by tank gage or

test the entire sampling system starting with the stream condition in the pipeline through collection and analysis of the sample. These are volume balance tests in which a known amount of water is injected into a known volume of oil of a known baseline water content. As these volumes pass the sampler under test, a sample is collected and the results analyzed for comparison against the known baseline water plus injected water. A3.2.4 The single sampler test requires that an assumption be made concerning the baseline water content during the time that test water is injected. Successful tests are dependent upon a constant baseline oil throughout the test. If a constant baseline oil cannot be ensured, inconclusive results will be obtained. A3.2.5 In the dual sampler test, the first sampler (that is, baseline sampler) is used to measure the baseline water content during the test. Test water is injected between the baseline and primary samplers. The primary sampler (one under test) is used to collect the baseline plus injected water sample. It is not necessary that the two sampling installations be of identical or similar design. A3.3 Preparations Prior to Acceptance Test: A3.3.1 Test the sample receiver and mixer as outlined in Practice D 5854, Annex A2. During the sampler acceptance test, water injection should last at least 1 h. The corresponding sample volume collected during a sampler acceptance test is usually less than the volume expected under normal conditions. Therefore, if the sample volume to be collected during the sampler acceptance test is less than the minimum volume at which the receiver and mixer have been tested, the receiver and mixer must be tested prior to the acceptance test in accordance with Annex A2 of Practice D 5854 using the oil and volume that are to be sampled. A3.3.2 Determine the method and accuracy by which the water and oil volumes will be measured. Water injection

!

I r

3" VALVE

PRESSU" E

,.,oo

/ STOP NUT 1" FROM WALL

.......... 3/4 POINT

4

//

PACK,,',G

SAF Y

GAGE MIDPOINT /

1/4 POINT

/

WALL

COLLECTORS

[~

NEEDLE VALVES

1 18 ~b HOLE

SILVER SOLDER TO END OF PROBE BODY

1/4" PROBE

P R O B E D E T A I L ( N O T E 4) NOTE 1--For pipes less than 30 cm (12 in.), delete the 1/4 and 1/4 points. NOTE 2--The punch mark on probe sleeve identifies the direction of probe openings. NOTE 3~When the probe is fully inserted, take up the slack in the safety chains and secure the chains tightly. NOTE 4--The probe is retractable and is shown in the inserted position. FIG. A3.1 Multi Probe for Profile Testing

659

TOGGLE.TYPE SHUT-OFF VALVES PROBE BODY

~{~) D 4177 A3.5.3 Water Injection Test: A3.5.3.1 Record water meter reading. A3.5.3.2 Start baseline sampler, injection of water and record tank gage or meter reading all in rapid succession. A3.5.3.3 Start primary sampler immediately prior to arrival of injected water. A3.5.3.4 Collect targeted sample volume with baseline sampler. A3.5.3.5 Stop baseline sampler, record tank gage or meter reading and shut off water injection all in rapid succession. A3.5.3.6 Record water meter reading. A3.5.3.7 Stop primary sampler after displacement of pipeline volume between baseline and primary samplers. A3.5.3.8 Analyze test samples. A3.5.3.9 Repeat A3.5.2.2 through A3.5.3.6 until two consecutive tests that meet the criteria in A3.6 have been obtained for both parts of the test. A3.6 Approval for Custody Transfer." A3.6.1 The acceptance test is valid and the automatic sampling system is acceptable for custody transfer if two consecutive test runs meet the following criteria: A3.6.2 Single Sampler Test: A3.6.2.1 The difference in the percent water in the beginning and ending baselines is 0. 1% or less, and A3.6.2.2 The deviation between the test sample and the known baseline plus injected water is within the limits shown in Table A3. I. A3.6.3 Dual Sampler Test: A3.6.3. l The difference between the two samplers during the baseline test must be within 0.1%, and A3.6.3.2 The difference between the second sampler (test sampler) and the baseline sampler plus injected water must be within the limits shown in Table A3. I. A3.6.4 Procedures to Follow if the Acceptance Test Fails: A3.6.4.1 Ensure volume of oil was calculated and recorded correctly. A3.6.4.2 Ensure volume of water was calculated and recorded correctly. Ensure scaling factor is correct or the meter factor has been applied to obtain correct volume, or both. A3.6.4.3 If inadequate stream conditioning in the pipeline is suspected, validate the sample point by one of the following: (a) Annex A2 to estimate the water-in-oil dispersion (b) A multiple point profile test as described in A3.7.1. A3.7 Component Performance Test: A3.7. l Profile Test to Determine Stream Condition--The extent of stratification or non-uniformity of concentration can be determined by taking and analyzing samples simultaneously at several points across the diameter of the pipe. The multipoint probe shown in Fig. A3.1 is an example of a profile probe design. This test should be conducted in the same cross-section of pipe where the sample probe will be installed. A3.7.l.1 Criteria for Uniform Dispersion and Distribution--A minimum of five profile tests meeting criteria in A3.8.2. If three of those profiles indicate stratification, the mixing in the line is not adequate. A3.7.1.2 Profile Probe--A probe with a minimum of five sample points is recommended for 30 cm (12-in.) pipe or

meter reading and simultaneously begin collecting grabs in the sample receiver. A3.4.5 Record the initial water meter reading. Then turn the water on and adjust injection rate. A3.4.6 A minimum of 1 h is recommended for the water injection. A3.4.7 Turn the water off and record the water meter reading. A3.4.8 Continue sampling into the receiver until the injected water is calculated to have passed the sampler. A3.4.9 Stop the collection of test sample and simultaneously record the oil volume by tank gage or meter reading. A3.4.10 Collect the second baseline sample(s). A3.4.11 Analyze the baseline samples. A3.4.12 Analyze the test sample. A3.4.13 Using the following Eq 35, calculate the deviation between the water in the test sample minus the water in the baseline, corrected to test conditions, compared to the amount of water injected. Dev = ( W t e s t - Wbl) -- Winj (35) where: Dev = deviation, vol %, Wt~t = water in test sample, vol %, Wbt = baseline water adjusted to test conditions, vol %

TOV- v =

W,,,g x

TOV

'

(36)

Wayg = average measured baseline water, vol %,

TOV = total observed volume (test oil plus injected water) that passes the sampler (barrels), V = volume of injected water in barrels (Note A), and Winj = water injected during test, vol % v =

TOV

x 100

(37)

A3.4.14 Repeat A3.4.3 through A3.4.13 until two consecutive tests that meet the criteria in A3.6 have been obtained. A3.4.15 When production water is used, make correction for dissolved solids as applicable. A3.5 Dual Sampler--Proving Test: A3.5.1 The dual sampler test is a two-part test. In the first part, the two samplers are compared to one another at the baseline water content. In part two of the test, water is injected between the two samplers to determine if the baseline water plus injected water is detected by the primary sampler. Refer to Annex A6. A3.5.2 Baseline Test Procedure." A3.5.2.1 Purge system to remove free water. A3.5.2.2 Establish steady flow in line. A3.5.2.3 Start baseline sampler. Record tank gage or meter reading. A3.5.2.4 Start primary sampler after pipeline volume between samplers has been displaced. A3.5.2.5 Stop baseline sampler after collecting targeted sample volume. A minimum of I h is recommended. Record tank gage or meter reading. A3.5.2.6 Stop primary sampler after pipeline volume between baseline and primary samplers has been displaced. A3.5.2.7 Analyze test samples. A3.5.2.8 Compare results and make sure they are within acceptable tolerance as per Table A3.1 before proceeding. 660

~

D 4177 T A B L E A3.3 Calculation of Point A v e r a g e s and Deviation NOTE l wThe system is rated with respect to the worst point average in the test: point average E has the largest deviation (-0.28). NOTE 2 - - F o r representative sampling, the allowable deviation is 0.05 ~, water for each 1 ~ water in the overall profile average. In this example, the allowable deviation is given by the (5.69 x 0.05) % W = :1:0.28 % W.

T A B L E A3.2

Typical Profile Test Data, in Percent V o l u m e of Water NOTE--FOr invalid sample or missed data point, the point should be shown as missing data and the remaining data averaged. Point (~, volume - water) Profile

1 2 3 4 5 6 7 8 9 10

A Bottom

0.165 0.094 13.46 8.49 6.60 6.73 7.88 2.78 1.15 0.58

B 1/4 Point

0.096 0.182 13.72 7.84 7.69 7.02 6.73 3.40 1.36 0.40

C Midpoint

0.094 0.135 13.21 8.65 7.69 6.48 6.73 3.27 1.54 0.48

D s/4 Point

0.096 0.135 12.50 8.65 6.60 6.73 7.27 3.08 1.48 0.55

E

Point (~, volume - wate0

Top A

0.096 0.135 12.26 8.33 8.00 5.38 5.96 2.88 1.32 0.47

Average of profiles 4 through 9 Deviation from overall profile average (Note 1) (~, water) Allowable deviation (Note 2)

B

C

D

Average E

5.61 5.67 5.73 5.64 5.31 +0.02 +0.08 +0.14 +0.05 -0.26

E%

5.59

(5.59 x 0.05) ~, water = :t:0.28 % water

A3.9.1 Install profile probe in line. Check that the probe is properly positioned and safely secured. A3.9.2 Position a slop can under the needle valves. Open the shut-off and needle valves and purge the probes for one minute (or sufficient time to purge 10 times the volume in the probe line). A3.9.3 Adjust needle valves so that all sample containers fill at equal rates. A3.9.4 Close shut-off valves. A3.9.5 Open the shut-off valves, purge the probe lines, and quickly position the five sample containers under the needle valves. Close shut-off valves. A3.9.6 Repeat A3.9.5 at intervals of not less than 2 min until a minimum of ten profiles have been obtained. A3.10 Sample Probe/Extractor Test." A3.10.1 The grab size should be repeatable within __.5 % over the range of operating conditions. Operating parameters that may affect grab size are sample viscosity, line pressure, grab frequency and back pressure on the extractor. A3.10.2 Test the sample probe/extractor by collecting 100 grabs in a graduated cylinder and calculate the average grab size. Perform the test at the highest and the lowest oil viscosity, pressure and grab frequency. A3.10.3 The average grab size will determine if the target number of grabs will exceed filling the sample receiver above the proper level. The average grab size is also used in determining the sampler performance (see Annexes A4 and A5). A3.11 Special Flow Meter Test: A3.11.1 If custody transfer meters are used, verification of the flow meter calibration is not necessary. A3.11.2 Special types of meters, such as those described in 12.2, can be verified by comparing the meter pacing the extractor with tank gages or custody transfer meters. Conditions for the test are: A3.11.2.1 The test should be conducted at the average flow rate experienced during normal operations. A3.11.2.2 The flow meter must be tested in its normal, operating location to determine if piping configuration affects its accuracy. A3.11.2.3 When using tank gages as a reference volume, the tank level changes must be large enough to give accurate volume readings. A3.11.3 Flow meters used for pacing sample extractors should be within :!:10 % of the volume measured by tank gaging or custody transfer meters.

larger. Below 30 cm (12-in.) pipe size, three sample points are adequate. A3.7.1.3 Sampling FrequencymProfile samples should not be taken more frequently than at 2 min intervals. A3.7.1.4 Probe Orientation--Profiles in horizontal lines must be taken vertically, where as profiles in vertical lines should be taken horizontally. A3.7.1.5 Test Conditions--The test should be set up to measure the worst case conditions including the minimum flow rate and lowest flow viscosity and density or other conditions as agreed upon. A3.7.1.6 Water Injection~The water injection method described in testing automatic sampling systems (see A3.2 and A3.3.3) is recommended. A3.7.1.7 Sampling--Sampling should begin 2 min before the calculated water arrival time and continue until at least ten profiles have been taken. NOTE A3.1--Probe installation and operation are covered in A3.9. As a safety precaution, the probe should be installed and removed during low pressure conditions. However,the probe should be equipped with safety chains and stops to prevent blow-out should it be necessary to remove it during operation conditions.

A3.8 Application of Dispersion Criteria: A3.8.1 Table A3.2 lists data accumulated during a typical profde test. Units are percent volume of water detected. Approximately 1000 barrels of seawater were added to a center compartment of a 76 000 dead weight ton crude oil tanker. The quantity of water was verified by water cut measurements shortly before the loading operation. A3.8.2 To apply the dispersion criteria, it is best to eliminate all profiles with less than 0.5 % water and the profile taken in the leading edge of the water (which occurs in Profile 3 of Table A3.2). Typically, a profile of the leading edge is erratic with respect to water dispersion. While it is a useful means of verifying arrival time, it hinders evaluation of profile data and can cause an unnecessarily reduced profile test rating. Calculate the point average and deviation for all other profiles with 1% or more water. (See Table A3.3.) A3.9 Water Profile Test ProceduresmRefer to Fig. A3.1 while following the steps of this procedure.

661

(~@) D 4177 A4. P E R F O R M A N C E

CRITERIA FOR PERMANENT INSTALLATIONS

A4.1 Calculations Prior to Operation:

(c) Probe operation. A4.3.2 Performance Factor (PF): SV PF ffi~ l 4- 0.10

PVe Expected parcel volume, m 3 b Expected extractor grab size, mL SV e Expected sample volume, mL (normally 80 % of receiver capacity) n Number of sample grabs expected

sv,

B

n ffi - b Frequency of sampling, m3/grab (Controller input)

Pv,

B ffi - -

SV

= pv s (38)

B

(42)

×b

A4.3.3 Flow Sensor Accuracy (SA): SA ffi eve° = 1 .4- 0.10

ev,

(39)

(43)

A4.3.4 Sampling Time Factor (SF):

n

A4.2 Data from the Sampling Operation: N Total number of grabs ordered by the controller SV Sample volume collected, mL SV c Sample volume calculated, mL PVs Parcel volume measured by sampler flow sensing device, m 3 PVco Custody transfer or outturn parcel volume, m 3

Sampling Factor ffi Total sampling time ffi 1 4- 0.05 Total parcel time Time parcel began Time parcel completed Total parcel time Time sampler begins operation Intermittent outages Time sampler stops operation Total sampling time Note: Record actual times sampler is not in service.

A4.3 Calculation o f Performance Report--The following calculations can be helpful in evaluating if a sample is representative: A4.3.1 Grab Factor (GF): SV GF = N × b 1 4- 0.05 (40)

(44)

A4.3.5 Sampler installation was tested according to Practice D 4177 Yes _ _ No _ _ Date tested A4.3.5.1 C o m p o n e n t s and variables involved are (a) average grab size, (b) flow sensor-to-controller link, (c) controller, (d) controller-to-probe link, (e) probe operation, and (f) flow sensor accuracy.

A4.3.1.1 C o m p o n e n t s and variables involved: (a) Average grab size, (b) Controller-to-probe link, and

A5. P E R F O R M A N C E

-- 1 + 0.10

(41)

CRITERIA FOR PORTABLE SAMPLING UNITS PVs Parcel volume measured by sampler flow sensing device, m 3 PVco Custody transfer or outturn parcel volume, m 3

A5.1 Representative sampling is m o r e difficult to document and verify when a portable sampler is used. The flow sensing device is usually limited in accuracy and turndown. Stream conditioning is usually limited to piping elements and flow velocity. The sampler controller data logging is usually limited. Special precautions and operating procedures with additional record keeping by the operator can overcome these limitations. A5.2 Calculations Prior to Operation:

A5.4 Calculation of Performance Report--The following calculations can be helpful in evaluating if a sample is representative: A5.4.1 Grab Factor (GF): SV GF -- N ×--~ ffi I £ 0.05

(40)

A5.4.2 Modified Performance Factor (PF, J:

Expected parcel volume, m 3 b Expected extractor grab size, mL SV e Expected sample volume, mL (normally 80 % of receiver capacity) n Number of sample grabs expected PV e

n --

sve b

SV PFm -- p ~ ffi 1 4- 0.10 ×b B

P V s is normally not available. When this is the case, use PVco which excludes the effect of flow sensor malfunction or inaccuracy on PF m. If PVs is available from the controller, calculate PF as in Annex A4. A5.4.3 Flow Sensor Accuracy ( S A ) - - T h e volume as measured by the sampler(s) flow sensor(s) is normally not available. The volume measured by the flow sensor(s) is calculated from the n u m b e r of grabs ordered by the controller(s). N×B SA-ffi 1 4- 0.10 (46)

(38)

B Frequency of sampling, m3/grab (Controller input)

eve

B --- - -

(45)

(39)

n

A5.3 Data from the Sampling Operation." N Total number of grabs ordered by the controller SV Sample volume collected, mL

PVco

662

1{~ D 4 1 7 7 VESSEL LOADING

LOCATION

DISCHARGE

TIME PUMPING BEGINS

ENDS

DATE PUMPING BEGINS

Probe ID (1)

Date

Time

Line No. (1)

Parcel

Calculation (2)

Into

Out of

Into

Out of

Flow

V e l o c i t y at

Velocity

Service

Service

Service

Service

Rate

Probe

Thru Line

NOTE 1--Une No. = Identificationletter or numberfrom Figs. A5.1 or A5.2. NOTE 2mVelocitiesshouldbe calculatedfor linesA to D in Fig. A5.1 as majorrate changesoccur and arms/hosesare addedor removedfrom service.The sameapplies to spools I to IV on the vessel.The same appliesfor line and spools designatedI to IV in Fig. A5.2. FIG, A5.1 Portable Sampler Operational Data Confirmation of Mixing end Flow Sensor Velocity

A5.4.4 Sampling Factor (SF): Sampling Factor = Total sampling time _- 1 at + 0.05 Total parcel time

ft/s) Yes _ _ No A5.4.5.2 No more than I0 % of the total free water in the tanks/compartments was pumped at flow rates of less than 2 m/s. Yes _ _ No ~ The criteria for stream conditioning is met if both answers are "Yes." A5.5 Line and Manifold DataIComplete forms as outlined in Tables A5.1 through A5.4 for each sample.

(44)

A5.4.5 Stream Conditioning: A5.4.5.1 For 95 % of the parcel volume, the flow rate in piping ahead of the sampler(s) was a m i n i m u m of 2 m/s (6.6

663

~ VESSEL

D 4177

LOCATION

DATE

TABLE G2 PORTABLE SAMPLER OPERATIONAL D A T A C O N F I R M A T I O N OF M I X I N G A N D FLOW SENSOR VELOCITY

Tank o r Compal~ment Number

Initial Free Water

Volume

Pumping Begins

%

Date

Pipe Velo=lty at Sampler

Cnlculetlone for Pipe Velooity at Sampler When Pumping Begino

Time

Total

NOTE 1--Free water is assumed to be pumped from a tank or compartment with the initial 5 % of the volume pumped. NOTE 2--A sample cannot be judged representaUveIf more than 10 %of the water found in the total parcel after the operation is complete is pumped as free water and the velocity In the piping ahead of the sampler at the time of pumping Is less than 2.44 m/s (8 ft/s). FIG. A5.2 Portable Sampler Operational Data ConflrmaUon of Free Water Sampled

664

t~) D 4177 Lines from Vessel Pump Room to Manifold

Vessel Manifold and Sampler Spools

Line No. 1 Line S i z e ~

Vessel Manifold

Line Size__

Line No. 2 Line Size__

Line Size__

t Line Size__

Line No. 3 Line S i z e ~

Line No. 4 Line Size__

Sample Spool D i a m e t e r ~ NOTE--Inthe spacesprovided,enter the tank numbersand linessizes usedduring loading. FIG. A5.3 Typical Piping Schematic to Be Recorded for Loading

665

I1~1~D 4177 Tanks

I Lines t;o I]ock ILInes, =nd Arms =nd or i I iHoses on ~he I

I

Sampler Spools on Vessel

Sock} i I

I ! I

I

Tank N°'-- I

!I

: I

I

I

I

I I Line Size I

I

'

Une No. A Arm/Hose Size

I

Line Size

.

i

I

i I i

I

Line No. 2

| Line No. B,

Arm/Hose Size

iI

I

.......

J,,

I

I

I

I I

I [ ~:~ ! Line Size__ !I Line No. 3 ] I ~

Arm~Hose Size

Line Size__

//~ i

Llne NO, ]] L Arm/Hose Size

Line No. 4 II I I Line Sizp = SampLer Spool Diame±er,

I

No~_

t

I

I Tank

Vesse[ ManiFold I

Line No. C

Tank N°~--

[ Line Slze__

l

I

,i

i

I

I

Tank No__

t

[ Line No. l! I

I

IOTE--In the spaces provided, enter the line sizes usedduringdischarge. FIG. A5.4 Typical Piping Schematic to be Recorded for Discharges

666

11~ D 4177 A6. S A M P L E R A C C E P T A N C E T E S T D A T A A6.1 Figure A6.1 is an example o f the sampler acceptance test data sheet.

Company.

Location:

Date:

Sampler ID:

C o m p a n y Witness:

Vmcosity:

API"

U~ Flow Rate:

_____

cts @ 40C

II __

Top Side Bottom Sample L o o p

__

Velocity

___

fps/mps

Sea;

Bracklsk;

LmeS~ze:

in.

Stream Conditioning: II L a b o r a t o r y Analysis: __ Power Mixing __ Centrifuge Static Mixer-Vertical Distillation Static M i x e r - H o r i z o n t a l Karl Fischer - - - - Pip]ng E l e m e n t - V e r t i c a l [[ Mass Piping E l e m e n t - H o r i z o n t a l [[ Volume -

-

---None

I Fresh;

bph/m3 F/C

--__

F'low Temp:

Crude Volume Determination by_.' in _Probe Design: Meter Tank lsokinetic T~Incremcn~ol. bbls/m31 Ell Beveled I Plam Sample Receiver Volume: gal/l I Other Test Sample Volume gal/l ] _ _ Grab Size(ml) T e s t Wa_t_cr:

of

O t h e r Witness:

SYSTEM DATA ('rtide Grade"

Test #

Jl

Production

TEST DATA Baseline Test Data 1. Single Sampler Method Baseline Test: (Wavg) = (lst basehne _ _

%

+

_ _

2nd baseline

2. Dual Sampler Method Baseline Test: a. Before Water Injection Comparison Test (Baseline Sampler % Primary Sampler _ _

%)/2

%)

Maximum Deviation From Table A.1 b.

D u n n g Water Injection Test: (Wavg)

Water Injection and Crude Volumes: 3. Water InJected (V) Stop Meter Totahzer Start Meter Totalizer V = Difference

=

%

=

%

=

%

gala gal/l

x

bbls/m3 (Meter Factor)

4. Crude Volume Stop 'Yank or Meter Totahzer Start Tank or Meter Totalizer Difference

(0.0238 gal/bbl or 0.001 l/m3)

bbl/m3 bbl/m3

bbls/m3 (Meter Factor asapphcable)

5. T O V ( h n e 3 + h n e 4 )

bbls/m3

CALCULATIONS: Dev = (Wtest - Wbl) - Winj Where: Wtest = Percent water in test sample 6. Wbl = Wavg x [(TOV - V ) / T O V ]

=

x [( (hne I or 2b)

7. Winj

]

=

%

(line 5)

=(V/TOV)xl00 =(

/

(line 3) Dev

) / (line 3)

(line 5)

= (

-

(Wtest)

%

) x 100 (line 5) . )

%

-

(hne 6)

(line

7 )

Maximum Deviation From Table A.1 NOTES: All percent figures are % Volume. Correct the volume of water injected for solids content,as applicable, if production water is used. Devtations must be within limits outlined in MPMS Chapter 8.2, Table A.1. Note below any physical or procedural changes made between consecutive test runs. Attach copy of sampler r e c e i v e r - m i x e r provin~ test report. See MPMS C h a p t e r 8.3. COMMENTS: -

-

-

-

FIG. A6.1

Sampler Acceptance Test Data Sheet 667

%

~

D 4177

APPENDIXES (Nonmandatory Information) Xl. DESIGN DATA SHEET FOR AUTOMATIC SAMPLING SYSTEM X 1.1 Figure X 1.1 is a sample of the design data sheet for an automatic sampling system. DESIGN DATA

P ROCESS-D-AT~, Pipeline I.D, Design pressure Operating pressure Other Flow Rate Maximum Normal Parcel or batch size

Type of Product Spec~ic Gravity or API Viscosity Vapor Pressure Expected water content (%) H20 (%) Other physical properties Sediment (%) SAMPLER DATA Grab size (ml/grab) Collection period: Hours Days__ W e e k s Probe inser~on length req~rlred Maximum grab rate required Air _ _ ( 1 =ressure) Electricdy .,.(Voltage) Proportion to time , Flow _ _ Meter manufacturer Type Stgnal Sampler Controller alarms:

iNSTALLATION: Permanent Portable Electrical Class~icatJonsat proposed installation site

Mininum

SAMPLE RECEIVER Total Volume Design pressure Design temperature Material of construction

Internal coating Portable Fixed Accessories: Pressure relief valve (saffings) Vacuum relief (settings) Pressure gauge Level gauge Volume weight/indicator Other

SYSTEM SPECIFICATIONS AVAILABLE UTIUTIES:

Electrical: Voltage Phase Air: Pressure Steam: Pressure

Hz Instrument Temperature

NOTES: PROJECT

COMPANY ADDRESS DATE PREPARED

DATE REQUIRED

Note: This document is part of the joint ASTM/API standards process and is for joint ASTM/API committee use only. It shall not be reproducted or circulated or quote in whole or in part, outside ASTM/API committee activities except with the approval of the chairman of the committee having jurisdiction or a higher ASTM/API author's Copyright 1991.

FIG. X1.1

Design Data Sheet for Automatic Sampling System

668

~

D 4177

X2. C O M P A R I S O N OF PERCENT S E D I M E N T A N D WATER V E R S U S U N L O A D I N G TIME P E R I O D

X2, l Figure X2.1 presents a comparison of percent sediment and water versus unloading time period.

13-

12-

11-

9" 8"

ul

• C R U D E - - 33,1 ~API.

7~

• INDICATED 1600 BARRELS OF FREE WATER IN 450,000 BARRELS CARGO.

6 -

• ALL WORKING COMPARTMENTS OPEN TO UNLOADING PUMPS SUCTION.

5-

• PUMPING RATE 8000 BARRELS/HOUR INITIALLY. UP TO 35,000 BARRELS/HOUR IN 30 MINUTES.

<

IZ LU O n.UJ 9,

4

e

\

3

e

2-

ee

I

I

.

START UNLOADING

;

~ 30

,

I

{

....

60

I

I

''

90

~'

t

J

I

120

,..~..

150

UNLOADING TIME PERIOD (MINUTES)

FIG. X2.1

C o m p a r i s o n of P e r c e n t S e d i m e n t a n d W a t e r V e r s u s U n l o a d i n g T i m e P e r i o d

The American Society for Testing and Materiels takes no position respecting the validity of any patent rights asserted in connection with any item mant/oned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is sub[eot to revision at any time by the responsible technical committee and must be reviewed every five years anti if not revised, either reapproved or withdrawn. Your comments are invited either for revLslon of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at e meeting of the responsible technical committee, which you may attend, It you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 100 Barr Harbor Drive, West Conshohockan, PA 19428.

669

(t~1~ Designation: D 4291 - 93 Standard Test Method for Trace Ethylene Glycol in Used Engine Oil 1 This standard is issued under the fixed designation D 4291; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last re.approval. A superscript epeilon (e) indicates an editorial change since the last revision or reapproval.

1. Scope 1.1 This test method provides for the determination of ethyleneglycol as a contaminant in used engine oil. This test method is designed to quantitate ethylene glycol in the range from 5 to 200 mass ppm. 1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. 1.3 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements see Notes 2 through 5. NOTE l mA qualitative determination of glycol-base antifreeze is provided in Test Method D 2982. ProcedureA is sensitiveto about 100 ppm. 2. Referenced Documents

2.1 ASTM Standards: D 1193 Specification for Reagent Water~ D2982 Test Methods for Detecting Glycol-Base Antifreeze in Used Lubricating Oils3 D4057 Practice for Manual Sampling of Petroleum and Petroleum Products 3 3. Summary of Test Method 3.1 The sample of oil is extracted with water and the analysis is performed on the water extract. A reproducible volume of the extract is injected into a gas chromatograph using on-column injection and the eluting compounds are detected by a flame ionization detector. The ethylene glycol peak area is determined and compared with areas obtained from the injection of freshly prepared known standards. 4. Significance and Use 4. I Leakage of aqueous engine coolant into the crank case weakens the ability of the oil to lubricate. If ethylene glycol is present, it promotes varnish and deposit formation. This test method is designed for early detection to prevent coolant from accumulating and seriously damaging the engine.

5. Apparatus 5.1 Gas Chromatograph--Any gas chromatograph equipped with the following: 5.1.1 Flame Ionization Detector, capable of operating continuously at a temperature equivalent to the maximum column temperature employed, and connected to the column so as to avoid any cold spots. 5.1.2 Sample Inlet System, providing for on-column injection and capable of operating continuously at a temperature equivalent to the maximum column temperature employed. 5.2 Recorder--Recording potentiometer with a full-scale response time of 2 s or less may be used. 5.3 Column--l.2-m (4-ft) by 6.4-ram (l/4-in.) copper tube packed with 5 mass % Carbowax 20-M liquid phase on 30/60 mesh Chromosorb T solid support. 5.4 Integrator--Manual, mechanical, or electronic integration is required to determine the peak area. However, best precision and automated operation can be achieved with electronic integration. 5.5 Centrifuge--RCF 600 minimum and centrifuge tubes with stoppers. 5.6 Syringe--A microsyringe, 10 ~tL is needed for sample introduction. 5.7 Pasteur Pipets. 5.8 Vials, 2 mL, with crimped septum caps. 6. Reagents and Materials 6.1 Purity of Reagents--Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society where such specifications are available. 4 Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination. 6.2 Purity of Water--Unless otherwise indicated, references to water shall be understood to mean reagent water as defined by Type II of Specification D 1193. 6.3 Air and Hydrogen--Warning: Precaution--See Note 2.) (Warning--See Note 3.) NOTE 2: Precaution--The air supply may be from a cylinder under high pressure. NOTE 3: Warning--Hydrogen is an extremelyflammable gas under pressure.

' This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.04 on Hydrocarbon Analysis and 1:)02.06 on Analysis of Lubricants. Current edition approved Aug. 15, 1993. Published October 1993. Originally published as D 4291 - 83, Last previous edition D 429t - 88. 2 Annual Book of ASTM Standards, Vol 11.01. 3 Annual Book of ASTM Standards, Vol 05.02.

4 "Reagent Chemicals, American Chemical Society Specifications," Am. Chemical Soc., Washington, DC. For suggestions on the testing of reagents not listed by the American Chemical Society, see "Reagent Chemicals and Standards," by Joseph Rosin, D. Van Nostrand Co., Inc., New York, NY, and the "United States Pharmacopeia."

670

@ D 4291 6.4 Calibration Mixtures--A minimum of three mixtures of water and ethylene glycol are prepared to cover the range from 5 to 200 mass ppm. Prepare one blend of approximately 2000 mass ppm ethylene glycol in water to provide for accurate weighing; then, prepare dilutions of that solution. 6.5 Carrier Gas, helium or nitrogen may be used with the flame ionization detector. (Warning: Precaution--See Note 4.) NOTE 4: Precaution--Helium and nitrogen are compressed gases under high pressure. 6.6 Ethylene Glycol 99 mass % pure. 6.7 n-Hexane, 99 mol % pure. (Warning: Precaution-See Note 5.) NOTE 5: Precaution--n-Hexaneis extremely flammable, harmful if inhaled, may produce nerve cell damage; see Annex A 1.I. 6.8 Liquid Phase and Solid Support, 5 mass % Carbowax 20-M liquid phase on 30/60 mesh Chromosorb T solid support. 6.9 Tubing, 6.4 m m (V4 in.) in outside diameter, 1.2 m (4 ft) long of copper. 6.10 Water, deionized or distilled.

7. Preparation of Apparatus 7.1 Column Preparation--Prepare the column by the following steps: 7.1.1 Prepare the packing, 5 mass % Carbowax 20-M liquid phase on 30/60 mesh Chromosorb T solid support, by any satisfactory method used in the practice of gas chromatography. NOTF- 6--Care should be taken in handling Chromosorb T solid support because of its static charge and softness. Chilling may be helpful in improving its handling properties. 7.1.2 Add the prepared packing to the copper tubing using only gentle tapping. Do not use vacuum or mechanical vibration to pack the column. Chromosorb T solid support is a resin which will deform under pressure or severe vibration. 7.2 Column InstallationmThe column must be attached to the injection port in such a way as to allow on-column injection. 7.3 Column Conditioning--The column must be conditioned at the operating temperature to reduce baseline shift due to bleeding of column substrate. 7.4 Chromatograph--Place in service in accordance with manufacturer's instructions. Typical operating conditions are shown in Table 1.

procedure in Section 10, injecting exactly 5 laL and record the area of the ethylene glycol peak. 8.2 Calculate a response factor for each calibration mixture as follows:

F = C/A

where: F --- response factor for ethylene glycol, C = concentration in mass ppm of ethylene glycol in water, and A = peak area for ethylene glycol. 8.3 Calculate an average response factor. NOTE 7--A calibration curve may be employed to obtain the response factor.

9. Preparation of Sample 9.1 Weigh approximately 3 g of sample, obtained as recommended in Practice D 4057, to the nearest 0.1 mg into the stoppered centrifuge tube. Add approximately 3 g of water, weighed to the nearest 0.1 mg, to the centrifuge tube. Add 5 m L of n-hexane. 9.2 Stopper and vigorously agitate the centrifuge tube for approximately 5 min. 9.3 Centrifuge the tube for 30 rain. 9.4 If there is no clear water layer, remove and discard the upper oil layer, taking care not to remove any of the water emulsion. Add another 5 m L of n-hexane and centrifuge for 30 min. 9.5 Remove an aliquot of the clear water layer from the centrifuge tube with a pasteur pipette and place in a 2-mL vial. Crimp a cap on the vial. 10. Procedure 10.1 Set the operating conditions of the chromatograph as described in 7.4. Inject exactly 5 p.L of water extract directly on the column. Record the peaks at a sensitivity that allows the maximum peak size compatible with the method of measurement. NOTE 8--A typical chromatogram is shown in Fig. 1. 10.2 After each sample analysis is completed, inject 5 p.L of water and allow to elute. NOTe 9--Small amounts of ethylene glycol are retained by the chromatographic column when higher concentrations of the glycol are injected. Therefore, when analyzing for very low concentrations of ethylene glycol,make repeated injections of water until no peak is found at the ethylene glycol retention time.

8. Calibration 8.1 Analyze each of the calibration mixtures following the TABLE 1

(1)

11. Calculations 11.1 The concentration of ethylene glycol in the original oil sample is calculated as follows:

TypicalOperating Conditions

Column: 1.2 m (4 It) by 6.4 mm (t/4 in.) OD copper Packing: 5 mass % Carbowax 20-M liquid phase on 30/60 mesh Chromosorb T solid support Detector: FID Detector temperature: 200°C Injection Port. temperature: 150°C Column oven temperature: 130°C Carrier gas flow: 60 mL/min Recorder range: 1 mV Sample size: 5 pL

Ethylene glycol, mass ppm = F x A x Ww/Ws

(2)

where: F = response factor for ethylene glycol as calculated in 8.3, A -- peak area for ethylene glycol, Ww = weight of the water as determined in 9.1, and Ws = weight of the oil sample as determined in 9.1. 671

q~ O 4291

12.1 The precision of this test method as obtained by

statistical examination of interlaboratory test results is as follows: 12.1.1 Repeatability--The difference between successive test results obtained by the same operator with the same apparatus under constant operating conditions on identical test material, would in the long run, in the normal and correct operation of test method, exceed the following values only in one case in twenty. Repeatability, n = 0.212X (3) where: X = ethylene glycol content, mass ppm. 12.1.2 Reproducibility--The difference between two single and independent results, obtained by different operators, working in different laboratories on identical test material, would in the long run, in the normal and correct operation of the test method, exceed the following values only in one ease in twenty. Reproducibility, R = 0.528X (4) where: X = ethylene glycol content, mass ppm. 12.2 Bias--Bias cannot be determined because there is no acceptable reference material suitable for determining the bias for the procedure in this test method.

s Cooperative data arc a v a i l a b l e f r o m A S T M b y r e q u e s t i n g R R : D 0 2 - 1 1 6 7 .

13. Keywords 13.1 antifreeze; used engine oil

u O

•

m

o O

--

e-

I

0

!

I

2 FIG. 1

I

I

I

t

!

I

4 6 8 Time, Mlnutea

l

1

10

Typical Chromatogram

12. Precision and Bias s

ethylene glycol; gas chromatography;

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned In this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, ere entirely their own responsibility. This standard is subject to revision at any time by the responalble technical committee and must be reviewed every five years and if not revised, either respproved or withdrawn. Your commenta are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your commente will receive careful consideration at a meeting of the responsible technical committee, which you may attend, ff you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103.

672

~l~l~ Designation:D 4294-90 (1995)E1

An American National Standard

Standard Test Method for Sulfur in Petroleum Products by Energy-Dispersive X-Ray Fluorescence Spectroscopy 1 This standard is issued under the fixed designation D 4294; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (~) indicates an editorial change since the last revision or reapproval. ~J NOTEmSection 16 was added editorially in July 1995.

1. Scope I. 1 This test method covers the measurement of sulfur in hydrocarbons such as naphthas, distillates, fuel oils, residues, lubricating base oils and nonleaded gasoline. The concentration range is from 0.05 to 5 mass %. 1.2 This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific precautionary statements, see Section 7. 1.3 The values stated in SI units are to be regarded as the standard. The preferred concentration units are mass % sulfur. 2. Referenced Documents

2.1 A S T M Standards: D4057 Practice for Manual Sampling of Petroleum and Petroleum Products 2 D 4177 Practice for Automatic Sampling of Petroleum and Petroleum Products 2

3. Summary of Test Method 3.1 The sample is placed in the beam emitted from an X-ray source. The excitation energy may be derived from a radioactive source or from an X-ray tube. The resultant excited characteristic X radiation is measured, and the accumulated count is compared with counts from previously prepared calibration samples to obtain the sulfur concentration in mass %. Three groups of calibration samples are required to span the concentration range 0.05 to 5 mass % sulfur.

5. Interferences 5.1 Samples containing heavy metal additives, lead alkyls, etc., may interfere with the test method. Elements such as silicon, phosphorus, calcium, potassium, and halides interfere if present in concentrations of more than a few hundred milligrams per kilogram. Consult instrument manufacturers' instructions for specific interference data. Materials used in the study to determine precision contained up to 250 mg/kg vanadium, 50 mg/kg nickel, and 15 mg/kg iron with no detectable bias introduced. 6. Apparatus 6.1 Energy-dispersive X-ray Fluorescence Analyzer--Energy-dispersive X-ray fluorescence analyzer may be used if its design incorporates, as a minimum, the following features and if test results from it are shown to be equivalent on the samples of interest. Required design features include: 6. I. 1 Source of X-ray Excitation, with significant energy above 2.5 KeV. 6.1.2 Removable Sample Cup, equipped with replaceable X-ray transparent plastic film windows and providing a sample depth of at least 3 mm. 6.1.3 X-ray Detector, with high sensitivity at 2.3 KeV. 6.1.4 Filters or other means of discriminating between sulfur Ka radiation and other X-rays. 6.1.5 Signal Conditioning Electronics that include the functions of pulse counting and pulse height analysis. 6.1.6 Display or Printer that reads out in counts, % sulfur, or both. NOTE l--Precaution--In addition to other precautions, if a radioactive source is used, it must be well shielded to international standard requirements and, therefore, not present any safety hazard. However, attention to the source is only to be carried out by a fully trained and competent person using the correctshieldingtechniques.

4. Significance and Use 4.1 The quality of many petroleum products is related to the amount of sulfur present. Knowledge of sulfur concentration is necessary for processing purposes. There are also regulations promulgated in federal, state, and local agencies which restrict the amount of sulfur present in some fuels.

6.2 Analytical Balance, capable of weighing to the nearest 0.1 rag. NOTE 2 - - O p e r a t i o n of analyzers using X-ray tube sources is to be

conducted in accordance with the manufacturer's safety instructions.

7. Reagents and Materials 7.1 Purity of Reagents--Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents conform to the specifications of the Committee on Analytical Reagents of the American Chemical

t This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.03 on Elemental Analysis. Current edition approved May 25, 1990. Published July 1990. Originally published as D 4294 - 83. Last previous edition D 4294 - 83 tj. 2 Annual Book of ASTM Standards, Vol 05.02.

673

D 4294 Society where such specifications are available) Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination. 7.2 Di-n-Butyl Sulfide, sulfur content 21.91 mass %.4 NOTE 3: Warning--Di-n-butylsulfideis flammableand toxic.

TABLE 1

C o m p o s i t i o n of Primary Standards

Sulfur Content,

Mass of

mass %

White Oil, g

Mass of DI-n-Butyl Sulfide, g

5 2.5 1

48.8 44.7 47.7

14.4 5.7 2.3

7.3 White Oil, ACS reagent grade or less than 20 mg/kg sulfur.

TABLE 2

8. Sample Cell Preparation 8.1 Clean and dry cells before use. Disposable sample cups are not to be reused. Window material usually is 6 lxm polyester or polycarbonate film. Handling of the film must be kept to an absolute minimum to prevent contamination. Renewal of the window is essential for the measurement of each sample. NOTE 4: CautionnSamplesof high-aromaticcontent will probably dissolve polycarbonatefilms. 9. Calibration and Standardization

9.1 Preparation of Standards." 9.1.1 Make primary standards by weighing the components separately and not by dilution from a concentrate at three concentrations: 5, 2.5, and 1 mass % sulfur. The exact sulfur content in each standard is to be calculated to three decimal places. 9.1.2 Accurately weigh approximately the appropriate quantity of white oil, shown in Table 1, into a suitable, narrow-necked container and then accurately weigh in approximately the appropriate quantity of di-n-butyl sulfide. Mix thoroughly (a glass-coated magnetic stirrer is advisable) at room temperature. 9.1.3 Make calibration standards in three ranges by diluting primary standards with white oil (Table 2). 9.1.4 Prepare the aforementioned standards and suitable dilutions for the calibration graphs to cover the three ranges. A computer included with the analyzer may be used, if an internal multi-point calibration curve is provided. 9.2 Certified Calibration Standards 9.2.1 Calibration standards which are certified by a responsible standards organization may be used when applicable to the sample of interest. Such standards included Standard Reference Materials (SRM) prepared and certified by the National Institute of Standards and Technology (NIST), and Standard Sample of Sulfur in Residual Fuel Oil certified by the Japan Petroleum Institute. 9.2.2 NIST certified materials used in the study of this test method were designated as 1620, 1621, 1622, 1623, and 1624, and contained from 0.2 to 4.5 mass % sulfur. 9.2.3 Storage of Standards--Store standards in dark, glass-stoppered bottles in a cool, dark place until required. As soon as any sediment or change of concentration is observed, discard the standard.

Range

Sulfur, mass ~

1 2 3

0.05-1.0 1.0-2.5 2.0-5.0

Calibration Standards Sulfur Concentrations, mass 0.0 A 1.0 a 2.0 c

0.1 1.5 3.0

0.5 2.0 4.0

1.0 2.5 5.0

A White oil assumed to be 0.0 mass % sulfur. a 1.0 mass % sulfur standard from Range 1 can be used. c 2.0 mass ~ sulfur standard from Range 2 can be used.

10. Preparation of Apparatus 10.1 Set up the apparatus in accordance with the manufacturer's instructions. Whenever possible the instrument is run continuously to maintain optimum stability. 11. Sampling 11.1 Obtain a test specimen in accordance with Practice D 4057 or D 4177. If the test specimen is not used immediately, then thoroughly mix in the container prior to taking a portion for analysis.

12. Procedure 12.1 Prepare the sample cell and fill with sample to a minimum depth of 3 ram. Provide adequate head space, and if required, a cell vent hole to prevent bowing of the window when testing volatile samples. NOTE 4: WarningnAvoid spilling flammable liquids inside the analyzer. 12.2 Standards--Obtain four readings on each standard using the recommended counting time for the instrument (typically acceptable counting times are 50 to 300 s). Immediately repeat the procedure using freshly prepared cells and fresh portions of samples. From the data obtained, calculate the average reading for each sulfur concentration. Prepare a calibration graph from the averaged results. A computer included with the analyzer may be used, if an internal multi-point calibration curve is provided. 12.3 Samples for Analysis--Before filling the cell, it may be necessary to heat viscous samples so that they are easy to pour into the cell. Fill the cell to the required depth and ensure there are no air bubbles between the window and the liquid. Obtain two consecutive counts using the recommended counting time for the instrument on a portion of the sample. Calculate the average count for the sample. 13. Calculation 13.1 The concentration of sulfur in the sample is read from the calibration curve using the averaged counts for each oil. Record the results to two decimal places. If the analyzer includes a computer and provides for automatic multi-point calibration, the concentration values so computed are to be recorded.

3 Reagent Chemicals, American Chemical Society Specifications, American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed by the American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United Slates Pharmacopeia and National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville, MD. 4 Available from Phillips Petroleum Co., Bartlesville, OK.

674

(~1~ D 4294 TABLE 3

14. Report 14.1 Report the results as the total sulfur content, mass %, and state that the results were obtained according to Test Method D 4294. 15. Precision and Bias 15.1 PrecisionDThe precision of this test method as obtained by statistical analysis of interlaboratory test results is as follows: 15.1.1 Repeatability~The difference between successive test results obtained by the same operator with the same apparatus under constant operating conditions on identical test materials would, in the long run, in the normal and correct operation of the test method, exceed the following values only in one case in twenty (see Table 3). Repeatability = 0.029(S + 0.6) (1) where S = average value of two results, mass %. 15.1.2 Reproducibility--The difference between two single and independent results obtained by different operators working in different laboratories on identical test material

Repeatability and

Reproducibility

Average Value of Two Results, mass % sulfur

Repeatability, mass • sulfur

Reproducibility, mass % sulfur

0.5 1.0 2.0 3.0 4.0 5.0

0.03 0.05 0.08 0.10 0.13 0.16

0.07 0.10 0.16 0.23 0.29 0.35

would, in the long run, exceed the following values only in one case in twenty (see Table 3). Reproducibility = 0.063(S + 0.6) (2) where S = average value of two results, mass %. 15.2 BiasDThere was no observed bias within the reproducibility of the test method as determined in an interlaboratory test using NIST certified standards.

16. Keywords 16.1 sulfur; XRF; X-ray fluorescence

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and ff not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend, ff you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St,, Philsdelph/8, PA 19103,

675

( ~ l ~ Designation: D 4307 - 94 Standard Practice for Preparation of Liquid Blends for Use as Analytical Standards I This standard is issued under the fixed designation D 4307; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (d indicates an editorial change since the last revision or reapproval.

1. Scope 1.1 This practice describes a laboratory procedure for the preparation of small volumes of multicomponent liquid blends. 1.2 This practice is applicable to components that are normally liquids at ambient temperature and pressure, or solids that will form a solution when blended with liquids. Butanes can be included if precaution is used in blending them. 1.3 This practice is limited to those components that fulfill the following conditions: 1.3.1 They are completely soluble in the final blend. 1.3.2 They are not reactive with other blend components or with blend containers. 1.3.3 The combined vapor pressure of the blended components is such that there is no selective evaporation of any of the components. 1.3.3.1 The butane content of the blend is not to exceed 10 %. (Warning: Precaution--See Note 1.) Components with a vapor pressure higher than butanes are not to be blended.

mass and purities of the pure components. Volume percent can be calculated using the density of each component.

4. Significance and Use 4.1 The laboratory preparation of liquid blends of known composition is required to provide primary standards for the calibration of chromatographic and other types of analytical instrumentation. 5. Apparatus 5.1 Containers: 5.1.1 Vial, glass, threaded neck, approximately 22-mL capacity, short style. The vial can be wrapped with black tape to prohibit light from affecting light sensitive components. 5.1.2 Bottle Cap, molded plastic with polyethylene conical liner. 5.1.3 Bottle Cap, molded plastic with tin-foil liner. Tinfoil liners are preferred to other metal liners because they seal better. 5.1.4 Mininert Valve, screw cap, 24 mm. These caps are especially valuable for preparing blends that contain volatile components. 5.2 Balance, capable of weighing to O. I rag. 5.3 Pipet,dropping, medicine dropper. 5.4 Spatula, semi-micro, scoop style.

NOTE I: P r e c a u t i o n - - E x t r e m e l y f l a m m a b l e liquefied gas u n d e r pressure. Vapor reduces oxygen available for breathing.

1.4 The values stated in SI units are to be regarded as the standard. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements, see Note 1.

6. Reagents and Materials 6.1 Blend components, high-purity, as required depending on the composition of the proposed blend. 6. l.l To verify the purity of blend components, analyze each compound by the same technique for which the blend is intended or by another suitable technique. Check for other impurities such as water, if necessary. Water cannot be determined by most GC methods and must be measured by other procedures such as Test Method D 1364, or equivalent, and the result used to nomalize the chromatographic value. If any of the impurities found are other components of the blend, determine their concentrations and make appropriate corrections.

2. Referenced Document 2.1 A S T M Standards: D 1364 Test Method for Water in Volatile Solvents (Fischer Reagent Titration Method) 2 3. Summary of Test Method 3.1 The individual blend components are precisely weighed and combined in an inert, tight sealing glass vial or similar container. When volatility is a consideration the components of lowest vapor pressure (least volatile) are added first and the highest (most volatile) last. Mass (weight) percent composition of the final blend is calculated from the

7. Preblending Calculations 7.1 In order to make blends of components at specific levels, it is necessary to calculate beforehand the mass of each component required to achieve these levels. Calculate these masses as follows:

AT w,,=-f-~

i This practice is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.04.OA on Preparation of Standard Hydrocarbon Blends. Current edition approved July 1'5, 1994. Published September 1994. Originally published as D 4307 - 83. Last previous edition D 4307 - 93. 2 Annual Book of ASTM Standards, Vol 06.04.

where: WN = mass of component N to be added, g, A = desired percentage in the final blend, and 676

(i)

~ T

D 4307

ffi desired mass of the total final blend, g.

8. Procedure 8.1 Examine the vial and cap to verify that a leak-free closure is obtained. The rim at the top of the vial should be smooth and flat and the cap should fit snugly. 8.1.1 Glass vials are inert to most compounds and are the usual choice. Plastic containers are never used since specific compounds can preferentially diffuse through them. 8.1.2 Plastic caps with tin foil liners provide a good seal unless blend components react with the tin. Polyethylenelined caps usually provide a good closure but are not to be used for aromatic hydrocarbons and similar compounds since these materials will, with time, diffuse through the liner. 8.2 Weigh the vial and cap to the nearest 0.1 mg. Remove the cap and add the first component to the vial, being careful not to allow the component to contact the rim of the vial, which could produce losses. Liquids may be added by either pipet or medicine dropper while solids are usually added with a small spatula. Place the cap on the vial and reweigh to the nearest 0.1 mg. Repeat this procedure with each additional component always being careful not to allow the contents of the vial to contact the cap. After all components have been added and the final weighing completed, thoroughly shake the vial to mix the solution. 8.2.1 When volatile components are being combined, the lowest vapor pressure (least volatile) compound is added first and the highest (most volatile) last. 8.2.2 For blending very volatile components it is advisable to reduce the volatility when the vial is uncapped by cooling the vial to about 4"C between weighings. When this technique is utilized, the volatile component is added, and the vial is closed and weighed. The vial and contents then are chilled thoroughly before the vial is opened to allow addition of the next component. The next component is added quickly, the vial closed and the vial and contents brought to ambient temperature before the mass is obtained. Care is to be taken to ensure that water condensed on the exterior of the vial is removed before weighing. After weighing, the vial and contents are re-chilled before the vial is opened to permit addition of the next component. NOTE 2--Vials that are capped with Mininertvalveshave performed satisfactorilyfor preparing blends containingvolatilecomponents. 8.3 To prepare a blend containing components at low concentration, for example, mg/Kg, where the weighed quantities would be too small for sufficient accuracy, it is necessary to make an initial blend of those components at higher concentrations. Successive dilutions are than made until the final desired concentration is reached. For example,

if a blend is desired that contains 56 mg/Kg (mass-ppm) n-heptane in cyclohexane, weigh together 2 mL of n-heptane and 20 mL of cyclohexane. Make certain that between all weighings the unmixed liquid does not contact the container cap, which could cause preferential losses. After both components have been added, thoroughly mix this blend by shaking. Make three successive dilutions, with careful weighings, of I part (2 mL) of blend with l0 parts (20 mL) of cyclohexane. Shake thoroughly between each dilution. Each blend should have a finished volume of 22 mL so that quantities are large enough to weigh accurately. The massppm of n-heptane in the final blend is calculated from the recorded weights. 9. Calculations 9,1 Calculate the mass percent composition as follows: N, mass % =

W~, x 100

z(w~+

(2)

Wo + w e . . . . )

where:

WN, Wo, We = mass of components N, O, P, etc, g. 9. I. l When an added component is less than 100 % pure (see 5. l.l) corrections must be made to the mass of that compound as well as to other components included in the blend. For example, ifthe mass of Nadded to the blend is 3.0 g but previous analysis indicated it to be 95 % N, 3 % component O and 2 % component P, then the actual mass of N in the blend would be 2.85 g and 0.09 g and 0.06 g would need to be added to the masses of components O and P, respectively. 9.2 Calculate the volume percent composition as follows: N, volume % =

(Wtc/Dlv)x 100 Z[(WN/D~)+ ( W o / D o ) + ( W p / D p )

(3) . . .1

where:

W~, Wo, We = mass of components N, O, P, etc, g, and DN, Do, De ---density of components N, O, P, etc., all determined at the same temperature. 9.2.1 The final volume of the solution is not necessarily the same as the sum of the volumes of the components due to possible expansion or contraction on mixing.

10. Precision and Bias 10.1 No statement is made about the precision or bias for preparation of liquid blends since the result merely states whether there is conformance to the criteria for success specified in the procedure. 11. Keywords 11.1 analytical standards; liquid blends

677

q~) D 4307 The American Society for Testing end Materials takes no position respecting the validity of any patent right# asserted In connection with any item mentioned in this standard. Users of this standard ere expressly advised that determination of the validity of any such patent right#, and the risk of infringement of such rights, are entirely their own responsibility. This standard Is subject to revision at any time by the responsible technical committee and must be reviewed every five years and ff not revised, either reapproved or withdrawn. Your comments are Invited either for revision of this standard or for additional standard# and should be addressed to ASTM Headquarter#. Your comment# will receive careful consideration at a meeting of the responsible technical committee, which you may attend, ff you feel that your comments have not received e fair hearing you should make your view# known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103.

678

(~l~

Designation: D 4367 - 94a Standard Test Method for Benzene in Hydrocarbon Solvents by Gas Chromatography 1 This standard is issued under the fixed designation D 4367; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (~) indicates an editorial change since the last revision or reapproval.

1. Scope l.l This test method covers the determination by gas chromatography of benzene at levels from 0.01 to l volume % in hydrocarbon solvents. 1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 1.3 For hazard information and guidance, see the supplier's Material Safety Data Sheet. For specific hazard statements, see Section 7.

persons handling and using hydrocarbon solvents, but this test method is not intended to evaluate such hazards. 5. Apparatus 5.1 Chromatograph--Any gas chromatographic instrument that has a backflush system and flame ionization detector and that can be operated at the conditions given in Table I. The detector-recorder combination must produce a 4-ram deflection for a l-lxL specimen containing 0.05 volume % MEK when operated at maximum sensitivity. 5.2 Columns, one 0.8-m (2.5-ft) length of 3.2-mm (I/s-in.) outside diameter stainless steel tubing and one 4.6-m (15-ft) length of 3.2-ram (l/8-in.) outsider diameter stainless steel tubing. 5.3 Recorder, Strip Chart--Potentiometer with a fullscale deflection of 1 mV, a full-scale response time of 2 s or less, and a maximum noise level of_+0.3% of full scale. 5.4 Microsyringe, 5-1aLcapacity. 5.5 Pipets, measuring 1 and 2 mL, graduated in 0.01 mL; 5, 10, and 20-mL capacity. 5.6 Flasks, volumetric, 25 and 100-mL capacity. 5.7 Vibrator, electric. 5.8 Vacuum Source. 5.9 Evaporator, vacuum, rotary. 5.10 Flask, boiling, round-bottom, short-neck, with 24/40 T joint, 500-mL capacity. Suitable for use with the evaporator (see 5.9).

2. Referenced Documents

2.1 A S T M Standards: D 3606 Test Method for the Determination of Benzene and Toluene in Finished Motor and Aviation Gasoline by Gas Chromatography2 E 260 Practice for Packed Column Gas Chromatography3 E 300 Practice for Sampling Industrial Chemicals4 3. Summary of Test Method 3.1 An internal standard, methyl ethyl ketone (MEK), is added to the material and then introduced into a gas chromatograph equipped with two columns connected in series. The specimen passes first through a column packed with the nonpolar phase, methyl silicone, which separates the components by boiling point. After octane has eluted, the flow through the nonpolar column is reversed, flushing out the components heavier than octane. The octane and lighter components then pass through a column with the highly polar phase, 1,2,3-tris(2-cyanoethoxy)propane, that separates the aromatic and nonaromatic compounds. The eluted components are detected by a conventional detector and recorded on a strip chart, The peak areas are measured and the concentration of each component is calculated by reference to the internal standard.

TABLE 1 Instrument Conditions Found Satisfactory for Measuring Low Concentrations of Benzene in Hydrocarbon Solvents Detector Columns Length, m Outside diameter, mm Stationary phases Support

4. Significance and Use 4. I Benzene is classed as a toxic and carcinogenic material. A knowledge of the concentration of this compound may be an aid in evaluating the possible health hazards to

Reference column Temperature, °C Injection port Column, isothermal Detector block Carrier gas Flow rate, mL/min Recorder range, mV Chart speed, mm/min Specimen size, p_L Time to backflush, rain Total cycle time, min

1 This test method is under the jurisdiction of ASTM Committee D-I on Paint and Related Coatings, Materials, and Applications and is the direct responsibility of Subcommittee D01.35 on Solvents, Plasticize=s, and Chemical Intermediates. Current edition approved April 15, 1994. Published June 1994. Originally published as D 4367 - 84. Last previous edition D 4367 - 94. 2 Annual Book ofASTM StandardJ, Vol 05.02. 3 Annual Book of ASTM Standards, Vol 14.01. 4 Annual Book of ASTM Standards, Vol 15.05.

flame ionization two, stainless steel (A) 0.8; (B) 4.6 3.2 (A) methyl silicone,A 10 weight (B) TCEP, 25 weight (A) acid-washed calcined diatomite,a 60 to 80-mesh (B) acid-washed pink diatomaceous earth, s 80 to 100-mesh any column or restriction may be used 150 100 150 helium approximately 30 0 to 1 10 1.0 approximately 2 approximately 30

A OV-101, availablefrom Ohio Valley Specialty Chemicals Inc. (see Footnote 7). S Chromosorb W and P, available from Celite Corp. (see Footnote 6).

679

~

D 4367

5.11 Lamp, infrared. 5.12 Burets, automatic, with integral reservoir, 25-mL

Dissolve 5 g of the methyl silicone in approximately 50 mL of chloroform. (Warning--See Note 1.) Pour the methyl silicone-chloroform solution into the flask containing the support. Attach the flask to the evaporator (see 5.9), connect the vacuum, and start the motor. Turn on the infrared lamp and allow the packing to mix thoroughly until dry.

capacity. 6. Reagents and Materials

6.1 Purity of Reagents--Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, where such specifications are available. 5 Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination.

NOTE 1: Warning--Chloroformis a toxic material and inhalation must b¢ avoided.

6.2 Acetone. 6.3 Chloroform. 6.4 Diatomaceous Earth6--Acid-washed, 60 to 80 mesh and 80 to 100 mesh. 6.5 Helium, 99.99 % pure. 6.6 Methanol. 6.7 Methylene Chloride. 6.8 Methyl Ethyl Ketone (MEK), 99.9 mol %. 6.9 Methyl Silicone.7 6.10 1,2,3-Tris(2-Cyanoethoxy) Propane (TCEP). 8

6.11 Calibration Standards. 6.11.1 Benzene, 99 + mol %. 6.11.2 Isooctane, 99 + mol %. 6.11.3 n-Nonane, 99 ÷ mol %. 7. Hazards 7.1 Many hydrocarbon solvents are flammable and hazardous; use special precautions when handling them. Of the reagents used in this procedure, methanol, chloroform, methylene chloride, acetone, methyl ethyl ketone, benzene (see 6.11.1), and n-nonane are hazardous. 7.2 Benzene is volatile and highly flammable. Exercise care to prevent accidental ignition. Benzene is also carcinogenic and toxic; acute or chronic poisoning may result from inhalation of benzene vapor, absorption of benzene through the skin, or drinking benzene.

8. Sampling 8.1 Take samples of solvents to be analyzed by this test method using the procedures described in Practice E 300. 9. Preparation of Columns 9.1 Column Packing Preparation--Prepare the two packing materials, one containing 10% methyl silicone and the other 25% TCEP, as follows: 9.1.1 Weigh 45 g of the acid-washed calcined diatomite support 60 to 80 mesh, into a 500-mL flask (see 5.10).

9.1.2 Weigh 75 g of acid-washed pink diatomaceous earth, 80 to 100 mesh, into a 500-mL flask (see 5.10). Dissolve 25 g of TCEP in 200 mL of methanol and pour into the flask containing the support. Attach the flask to the evaporator (see 5.9), connect the vacuum, and start the motor. Turn on the infrared lamp and allow the packing to mix thoroughly until dry, but do not heat the packing above 180"C. 9.2 Column Preparation: 9.2.1 Clean the stainless steel tubing as follows: Attach a metal funnel to one end of the steel tubing. Hold or mount the stainless steel tubing in an upright position and place a beaker under the outlet end of the tubing. Pour about 50 mL of methylene chloride into the funnel and allow it to drain through the steel tubing into the beaker. Repeat the washing with 50 mL of acetone. Remove the funnel and connect the steel tubing to an air line, by means of vinyl tubing. Remove all solvent from the steel tubing by blowing filtered, oil-free air through or applying a vacuum. 9.2.2 Pack the 0.8-m (2.5-ft) tubing (Column A) with the methyl silicone packing (see 9.l.l) and the 4.6-m (15-ft) tubing (Column B) with the TCEP packing (see 9.1.2) as follows: Preform Columns A and B separately to fit the chromatographic instrument. Close one end of each tubing with a small, glass wool plug and connect this end to a vacuum source by means of a glass-wool packed tube. To the other end connect a small polyethylene funnel by means of a short length of vinyl tubing. Start the vacuum and pour the appropriate packing into the funnel until the column is full. While filling each column, vibrate the column with the electric vibrator to settle the packing. Remove the funnel and shut offthe vacuum source. Remove the top 6 mm (1/4in.) of packing and insert a glass wool plug in this end of the column. 9.3 Prepacked columns conforming to specifications listed in Table l, and in 5.2, 9. I, and 9.2 may be obtained from any reputable chromatography supply company. 10. Preparation of Chromatographic Apparatus and Establishment of Conditions 10.1 Column Conditioning--Join Columns A and B as shown in Fig. 1. Connect the inlet of Column A to the injection port of the chromatograph. Pass helium gas through the column at approximately 40 mL/min. Condition the columns in accordance with the following timetemperature schedule.

5 "Reagent Chemicals, American Chemical Society Specifications," Am. Chemical Soc., Washington, DC. For suggestions on the testing of reagents n o t listed by the American Chemical Society, see "Reagent Chemicals and Standards," by Joseph Rosin, D. Van Nostrand Co., Inc., New York, NY, and the "United Stales Pharmacopeia." 6Chromosorb P (80 to 100 mesh) and Chromosorb W (60 to 80 mesh), available from Celite Corp., 137 W. Central Ave., Lompac, CA 93436, have been found satisfactory for this purpose. 7 0 V 101, available from Ohio Valley Specialty Chemicals Inc., 115 Industry Rd., Marietta, OH 45750, has been found satisfactory for this purpose. s TCEP, available from Applied Science Laboratories, Inc., P.O. Box 440, State College, PA 16801, has been found satisfactory for this purpose.

Temperature, "C

Time, h

50

Ih Ih I 3

I00

150 170

10.2 Connect the outlet of Column B to the detector port. 680

~') D 4367 (a) Forward Flow

T VENT

J-

._~

COLUMN A METHYL SILICONE

S

w

IP, VENT

, ~

(b) Backflush

BOUNDARY

,•--OVEN

t..~

S

CARRIER GAS FROM CYLINDER

\ COLUMN S TCEP

T

LEGEND

I

I

P VENT

FLOW CONTROLLER

Iu~f~REFERENCE SlOE

B

PRESSURE INDICATOR D

6-PORT SWITCHING VALVE CARLE INSTRUMENTS CO. CAT NO. SOS4 FULLERTON,CA OR EOUIVALENT

D

FIG. 2

T FIG. 1

Flow Switching System

IN.Jr'c TIO N PO•T

mined backflush time. This should result in a chromatogram of isooctane with little or no n-nonane evident. 10.4.3 If necessary, make additional runs, adjusting the time to backflush until a chromatogram of all the isooctane and little or none of the n-nonane is obtained. This established backflush time, including the actual valve operations, must be used in all subsequent calibrations and analyses.

Tubing Assembly and Instrumentation

Adjust the operating conditions to those listed in Table 1, but do not turn on the detector circuits. Check the system for leaks. 10.3 Adjust the flow rate as follows: 10.3.1 Set the value in the forward flow mode (Fig. 2(a)) and adjust How Controller A to give the required flow rate (Table 1). Measure the flow rate at the detector vent, specimen side. 10.3.2 Set the valve in the backflush position (Fig. 2(b)) and measure the flow rate at the detector vent, specimen side. If the rate has changed, adjust How Controller B to obtain the required flow rate to within + 1 mL/min. 10.3.3 Turn on the detector circuit. Change the valve from forward flow to the backflush position several times and observe the baseline. There should be no baseline shift or drift after the initial peak resulting from the pressure surge with the valve change. If there is a baseline shift, slightly increase or decrease flow with Controller B to balance the baseline. (A persistent drift indicates leaks somewhere in the system.) 10.4 Determine time before backflushing, which varies for each column system and must be determined experimentally as follows: 10.4.1 Prepare a mixture of 5 volume % isooctane in n-nonane. Using the injection technique described in 11.3 and with the system in the forward flow mode, inject 1 pL of the isooctane-n-nonane mixture. Allow the chromatogram to run until the n-nonane has eluted and the recorder pen has returned to baseline. Measure the time in seconds from the injection until the recorder pen returns to baseline between the isooctane and n-nonane peaks. At this point all of the isooctane but essentially none of the n-nonane should have eluted. One half of the measured time approximates the time to backflush and should be from 30 to 120 s. 10.4.2 Repeat the run, including the injection, but switching the system to the backflush mode at the deter-

11. Calibration and Standardization 11.1 Standard Solutions--Prepare seven standard solutions covering the range of 0 to 1 volume % benzene as follows: For each standard, measure the volume of benzene listed below into a l O0-mL volumetric flask. Dilute to volume with isooctane, with all components and glassware at normal room temperature, and mix thoroughly. Benzene Volume %

mL

1 0.5 0.25 0.10 0.05 0.01 0.005

1 0.5 0.25 0.10 0.05 0.01 0.005

11.2 Calibration Solutions--Accurately measure 0.5 mL of MEK into a 100-mL volumetric flask, fill to the mark with the first standard solution (see 11.1), and mix thoroughly. Repeat with each of the other standard solutions. 11.3 Chromatographic Analysis--Using the conditions established in 10.3 and 10.4, chromatograph each of the calibration solutions after injecting them as follows: Hush the 5-pL microsyringe at least three times with the calibration solution and then fill with about 3 pL, avoiding inclusion of air bubbles in the syringe. Slowly eject the material until 1.0 gL remains in the syringe. Wipe the needle with a tissue and draw back the plunger to admit 1 pL of air into the syringe. Insert the needle of the syringe into the septum cap of the chromatograph and push through the 681

(~

D 4367'

septum until the barrel of the syringe is resting against the septum cap; then rapidly push the plunger to the hilt and immediately withdraw the needle from the injection port.

NOTE 4--If the calibration is linear, a least-squares calculation may be performed to obtain a calibration factor. The precision statement in Section 15 was developed from results obtained from calibration plots and may not apply if calibration factors are used.

NOTE 2--This injection technique is necessary to obtain sharp symmetrical peaks.

12. Procedure 12. I Test Solution--Accurately measure 0.5 m L of M E K into a 100-mL volumetric flask. Fill to the mark with the material under test and mix well. 12.2 Chromatograph a specimen from the test solution using the conditions established in 10.3 and 10.4 and the injection technique described in 11.3. NOTE 5--The valves must be turned to the backflush mode at the established backflush time so that undesirable components do not enter Column B. 12.3 Identify on the chromatogram the benzene and the internal standard M E K peaks from the retention times of the standards. NOTE 6--The order of elution is nonaromatic hydrocarbons, benzene, MEK, and toluene when using the specified columns, as shown in Fig. 4. 12.4 Measure the areas under the benzene peak and under the M E K peak by conventional methods.

1 1.4 Calibration--Measure the areas of the benzene and of M E K peaks by conventional means (Note 3). Calculate the ratio of the benzene peak area to the M E K peak area. Plot the concentration of benzene versus the ratio as in Fig. 3. The calibration must be done to ensure that the entire chromatographic system is operating properly and that the concentration of any one component has not exceeded the linear response range of any part of the s y s t e m n c o l u m n , detector, integrator, and other components. The calibration plot should be linear (Note 4). Determine the retention times for each component for future identification. NOTE 3--The precision statement in Section 15 was developed from results obtained using electronic integrators or on-line computers. The precision statement may not apply if other methods of integration or peak area measurement are used.

=z

!

o.ol

z

4

S

i

7 I#c~

I

I

•

i

i

t

IIl.#

~l

P E A K A R E A RATIO, B E N Z E N E / M E K

NOTE--Determine for each analytical system.

FiG. 3 TypicalCalibrationCurvefor Benzene

682

I

•

$

I

V IS~

(1~ D 4367 14. Report 14.1 Report the following information: benzene content in volume or weight % to the nearest 0.005 %.

tAI Z

t.-

15. Precision and Bias 9 15.1 Precision--The precision statements are based on an intcrlaboratory study in which analysts in each of six laboratories analyzed seven hydrocarbon solvent samples, including beptane, VM&P naphtha, mineral spirits, toluene, and aromatic solvent 100 on two different days. To each solvent, initially containing essentially no benzene, 0.1 to 0.5 volume % benzene was added. The within-laboratory standard deviation was found to be 0.0094 % absolute with 42 df and the between-laboratory standard deviation was 0.022 % absolute with 49 dr. Based on these standard deviations, the following criteria should be used for judging the acceptability of results at the 95 % confidence level: 15.1.1 Repeatability--Two results, each the mean of duplicates, obtained by the same operator on different days should be considered suspect if they differ by more than 0.027 % absolute. 15.1.2 Reproducibility--Two results, each the mean of duplicates, obtained by operators in different laboratories should be considered suspect if they differ by more than 0.063 % absolute. 15.2 Bias--Bias can not be determined for this test method because there is no available material having an accepted reference value.

° JUI i N Z w

Z Q: w tl.

=

)

Z ¢.= O I Z

O TIME,

FIG. 4

MINUTES

Typical Chromatogram

13. Calculation 13.1 Calculate the ratio of peak area of benzene to the peak area of MEK. Read from the calibration curve the volume % of benzene corresponding to the calculated peak ratio. 13.2 If the results are desired on a weight basis, convert to weight % as follows: Benzene, weight % = (V/D) x 0.8844 where: V = benzene, volume %, and D = relative density of sample at 15.6/15.6"C (60/60"F).

16. Keywords 16. l benzene content; gas chromatography; hydrocarbon solvents 9 Supporting data are available from ASTM Headquarters. Request RR:D011038.

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend, ff you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103.

683

Designation: D 4377 - 93a

0 IPN tilt, I~.qil ) I Ull

Designation: MPMS (Chapter 10.7) Designation: 356/93

Standard Test Method for Water in Crude Oils by Potentiometric Karl Fischer Titration 1 This standard is issued under the fixed designation D 4377; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapprovai. A superscript epsilon (~) indicates an editorial change since the last revision or reapprovai.

This test method has been approved by the sponsoring committees and accepted by the cooperating societies in accordance with established procedures.

aliquot of the crude, in a mixed solvent, is titrated to an electrometric-end point using Karl Fischer reagent.

1. Scope 1.1 This test method covers the determination of water in the range from 0.02 to 2 % in crude oils. Mercaptan and sulfide (S- or H2S) sulfur are known to interfere with this test method (see Section 5). 1.2 This test method is intended for use with standard Karl Fischer reagent or pyridine-free Karl Fischer reagents. 1.3 The values stated in SI units are to be regarded as the standard. 1.4 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate sofety and health practices and determine the applicability of regulatory limitations prior to use. Specific precautionary statements are given in Notes 1, 2, 3, 4, and 5.

4. Significance and Use 4.1 A knowledge of the water content of crude oil is important in the refining, purchase, sale, or transfer of crude oils.

5. Interferences 5.1 A number of substances and class of compounds associated with condensation or oxidation-reduction reactions interfere in the determination of water by Karl Fischer. In crude oils, the most common interferences are mercaptans and sulfides. At levels of less than 500 ~g/g (ppm) (as sulfur) the interference from these compounds is insignificant. For more information on substances that interfere in the determination of water using the (Karl Fischer reagent) titration method see Test Method E 203.

2. Referenced Documents

2.1 A S T M Standards: D 1193 Specification for Reagent Water 2 D 1744 Test Method for Water in Liquid Petroleum Products by Karl Fischer Reagent 3 D4006 Test Method for Water in Crude Oil by Distillation 4 D4057 Practice for Manual Sampling of Petroleum and Petroleum Products4 D4177 Test Method for Automatic Sampling of Petroleum and Petroleum Products4 E 203 Test Method for Water Using Karl Fischer Reagent 5

6. Apparatus 6.1 Karl Fischer Apparatus, using electrometric end point. A suggested assembly of the apparatus is described in Appendix X 1 of Test Method D 1744. 6.1.2 Presently there is available on the market commerciai Karl Fischer titration assemblies, some of which automatically stop the titration at the end point. Instructions for operation of these devices are provided by the manufacturer and not described herein. This test method is not intended for use with coulometric Karl Fischer titrators. 6.2 Mixer, to homogenize the crude sample. 6.2.1 Non-Aerating, High-Speed, Shear Mixer, 6 capable of meeting the homogenization efficiency test described in Annex A 1. The sample size is limited to that suggested by the manufacturer for the size of the probe. 6.3 Syringes:

3. Summaryof Test Method 3.1 After homogenizing the crude oil with a mixer, an i This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.03 on Elemental Analysis. Current edition approved Aug. 15, 1993. Published October 1993. Originally published as D 4377 - 84. Last previous edition D 4377 - 93. "Annual Book of ASTM Standards, Vol I 1.01. 3Aanual Book of ASTM Standards, Vol 05.01. 4 Annual Book of ASTM Standards, Vol 05.02. s Annual Book of ASTM Standards, Vol 15.05.

6 The following mixers 'were used in a cooperative program and have been found satisfactory for samples under 300 mL; Ultra Turrax Model TP 18110, available from Tekmar Co., P. O. Box 37202, Cincinnati, OH 45222; Brinkman Polytron Model PT 35, Available from Brinkman Instruments ln¢., Cantiagn Road, Westbury, NY 11590; and Kraft Apparatus Model S-25, SGA, Bloomfield, NJ.

684

~

D 4377

6.3.1 Samples and base liquid are most easily added to the titration vessel by means of accurate glass syringes with LUER fittings and hypodermic needles of suitable length. The bores of the needles used should be kept as small as possible, but large enough to avoid problems arising from back pressure/blocking whilst sampling. Suggested syringe sizes are as follows: 6.3.1.I Needle 10 ~L, long enough to dip below the surface of the base solution in the cell during the standardization procedure (see Section 9). 6.3.1.2 Crude OilSamples, 2.5 mL, 5 mL, and 10 mL (see Section I0). 6.3.1.3 Sample Solvent, 20 mL or larger.

7. Reagents and Materials

7.I Purity of Reagents--Reagcnt grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, where such specifications are available,v Other grades may be used, provided it is firstascertained that the reagent is of sufficientlyhigh purity to permit its use without lessening the accuracy of the determination. 7.2 Purity of WatermUnlcss otherwise indicated, references to water shall be understood to mean reagent water as defined by Type IV of Specification D 1193. 7.3 1-Ethylpiperidine(99 + percent). NOTE 1: Warning--Irritant. Flammable. 7.4 Karl Fischer Reagents, Standard reagent c0ptaining pyridine (7.4.1) or pyridine-free reagent (7.4.2). 7.4.1 Karl Fischer Reagent Ethylene Glycol Monomethyl Ether Solution, stabilized, containing pyridine, (1 mL = 5 mg of water)--Fresh Karl Fischer reagent must be used. Must be used with solvent in 7.6. I. NOTE 2: Warning~Combustible.Harmfulif swallowed,inhaled, or absorbed throughthe skin. 7.4.2 Pyridine-Free Karl Fischer (one-component) reagent diluted with xylene--Dilute three parts pyridine-free Karl Fischer (one-component) reagents (1 mL = 5 mg water) to 1 part xylene. Fresh Karl Fischer reagent must be used. (Warning--See Note 2) Must be used with solvent in 7.6.2. 7.5 Methanol (anhydrous), Maximum 0.1% water but preferably less than 0.05 % water. NOTE 3: Warning--Flammable. Vapor harmful. May be fatal or cause blindnessif swallowedor inhaled.Cannotbe madenonpoisonous. 7.6 Sample Solvent--Use 7.6.1 for standard Karl Fischer reagent containing pyridine and 7.6.2 for pyridine-free Karl Fischer reagent. 7.6.1 Sample Solvent--Mix 40 mL of l-ethylpiperidine, 20 mL of methanol, and 40 mL of Karl Fischer reagent in a 7 "Reagent Chemicals, American Chemical Society Specifications," Am. Chemical See., Washington, DC. For suggestions on the testing of reagents not listed by the American Chemical Society, see "Reagent Chemicals and Standards," by Joseph Rosin, D. Van Nostrand Co., Inc., New York, NY, and the "United States Pharmacopeia." s Pyridine-free Karl Fischer reagent and two-component solvent used in the cooperative program and found to be satisfactory are available from Crescent Chemical Co., Inc., 1324 Motor Parkway, Hauppauge, NY 1178S under the name of Hydranal ® a registered trademark of Riedel Dchaen--Composite 5 and Hydranal--solvent.

TABLE 1 TestSample--% Water ContentBased on Sample Size Expected Wat~ Content, ~

Semple Size, g

0-0.3 0.3-1 1-2

5 2 1

sealable glass bottle. Allow this mixture to sit overnight before adding 200 mL of xylene. Additional methanol may be required in some cases for the proper function of the electrodes. (Warning--see Note 1.) 7.6.2 Sample Solventfor Pyridine-FreeReagents--Mix 3 parts chloroform to 1 part pyridine-free solvent using solvent part of two-component reagents (contains SO2 and odorless amine dissolved in methanol) and store in a scalable glass bottle. An evaluation of a number of crude oils has demonstrated that xylene can be substituted for chloroform with no apparent change in accuracy of this test method. (Warning-See Notes 2 and 4.) 7.7 Xylene, reagent grade. Less than 0.05 % water. NOTE 4: Warning--Flammable.Vapor harmful. 7.8 Chloroform, reagent grade. NOTE 5: W a r n i n g - - H a r m f u l if inhaled or swallowed. Carcinogen (animal positive). Skin and eye irritant. May produce toxic vapors if

burned. 8. Sampling and Test Samples 8.1 Sampling, is defined as all the steps required to obtain an aliquot representative of the contents of any pipe, tank, or other system, and to place the sample into the laboratory test container. The laboratory test container and sample volume shall be of sufficient dimensions and volume to allow mixing as described in 8.1.2.1. 8.1.1 Laboratory Sample--Only representative samples obtained as specified in Practice D 4057 and D 4177 shall be used for this test method. 8.1.2 Test SamplesmThe following sample handling procedure shall apply in addition to those covered in 8.1.1. 8.1.2.1 Mix the test sample of crude oil immediately (within 15 min) before analysis to insure complete homogeneity. Mix the test sample at room temperature (25°C) in the original container. NOTE 6--The sample should be mixed at room temperature (25"C) or less. Mixingof the sampleshouldnot increasethe temperatureof the sample morethan 10*C,or a lossof water may occur. The typeof mixer depends on the quantity of crude. Beforeany unknownmixer is used, the specificationsfor the homogenizationtest, AnnexAI, must be met. The mixer must be re-evaluatedfor any changes in the type of crude, quantity of crude, or shape of the samplecontainer. 8.1.2.1.1 For small sample volumes, 50 to 500 mL, a non-aerating, high speed, shear mixer is required. Use the mixing time, mixing speed, and height above the bottom of the container found to be satisfactory to Annex A I. Clean and dry the mixer between samples. 8.1.2.2 The test sample size is selected as indicated in Table 1 based on the expected water content. 9. Calibration and Standaidization 9.1 Standardize the Karl Fischer reagent at least once daily.

685

~I~ D 4377 water still vary by more than 2 %, it is likely that either the Karl Fischer reagent or the sample solvent, or both, have aged. Replace these with fresh reagents and repeat the procedure for calibration and standardization. 9.6 Determine and record the mean water equivalence value.

9.2 Add enough solvent to the clean, dry titration vessel to cover the electrodes. The volume of solvent depends on the size of the titration vessel. Seal all openings to the vessel and start the magnetic stirrer for a smooth stirring action. Turn on the indicating circuit as prescribed in Test Method D 1744. Add Karl Fischer reagent from the buret until the end point is reached. Swirl the titration vessel to dry the inside walls of the vessel. Add more Karl Fischer reagent if needed, until a steady end point is reached for at least 30 s. 9.3 Standardize the Karl Fischer reagent with distilled water by one of the following methods: 9.3.1 From a water filled weighing pipet or syringe previously weighed to the nearest 0.1 rag, add 1 drop of distilled water (about 20 rag) to the sample solvent at end point conditions and reweigh the syringe. Record the weight of the water added. Titrate the water with Karl Fischer reagent added from the buret until a steady end point is reached for at least 30 s. Record to the nearest 0.01 mL the volume of the Karl Fischer reagent needed to reach the end point. NOTE 7--After adding water do not shake the cell.

NOTE 8--When wiping the needle exercise care, so not to siphon liquid throughthe tip of the needle. 9.3.2 Fill a 10-1aL syringe with water taking care to eliminate air bubbles, wipe the needle with a paper tissue to remove any residual water from the needle and accurately determine the weight of syringe plus water to 0.1 rag. Add the contents of the syringe to the sample solvent in the cell which has been adjusted to the end point ensuring that the tip of the needle is below the surface of the sample .solvent. Reseal the vessel immediately. Remove any solvent from the needle by wiping with a paper tissue and reweigh the syringe to 0.1 mg. Titrate the water with Karl Fischer reagent as in 9.3.1. 9.4 Calculate the water equivalence of the Karl Fischer reagent as follows: F= W/T where: F = water equivalence of the Karl Fischer reagent, mg/mL, W-- water added, mg, and T = reagent required for titration of the added watei', mL. 9.5 Duplicate values of water equivalence should agree within 2 % relative. If the variation between the two titrations is greater than 2 % relative, discard the contents of the titration vessel. Introduce a further portion of sample solvent into the vessel and repeat the standardization procedure. If the titrations for two further portions of distilled TABLE 2 Mass Water 0.05 0.1 0.3 0.5 0.7 1.0 1.3 1.5 1.7 2.0

11. Calculations

11.1 Calculate the water content of the sample as follows: water, mass % = CF/W(IO) where: C = Karl Fischer reagent required to titrate the sample, mL, F = water equivalence of Karl Fischer reagent, mg/mL, W = sample used, g, and 10 -- factor for converting to percent. 12. Precision and Bias9 12.1 The precision of this test method as determined by the statistical examination of interlaboratory test results is as follows: 12. I. l Repeatability--The difference between successive results obtained by the same operator with the same apparatus under constant operating conditions on identical test material would, in the long run, in the normal and correct operation of the test method, exceed the following values only in one case in twenty. 12. I. I. l Standard Karl Fischer Reagents: r = 0.034 (XU3)

Precision Intervals A

Standard Karl Fischer Reagents

Pyrldine-Free Reagents

r

R

r

R

0.013 0.016 0.023 0.027 0.030 0.034 0.037 0.039 0.041 0.043

0.041 0.052 0.074 0.088 0.099 0.111 0.121 0.127 0.132 0,140

0.012 0.015 0.021 0.025 0.028 0.032 0.035 0.037 0,038 0.040

0.035 0.044 0.064 0.075 0.084 0.095 0.104 0.109 0.113 0.120

10. Procedure 10.1 Add the fresh sample solvent to the titration vessel and bring the solvent to end-point conditions as described in 9.2. 10.2 Add the crude to the titration vessel immediately after the mixing step described in 8.1.2.1 using one of the following methods: 10.2.1 Starting with a clean, dry syringe (10 or 5 mL), rinse the syringe two times with the sample and discharge to waste. Withdraw the required amount of sample and discharge any air bubbles. Weigh the syringe to the nearest 0.1 rag. Inject the sample into the titration vessel, clean the needle with a paper tissue, and reweigh the syringe. Titrate the sample until a steady end point for at least 30 s is reached and record the volume of Karl Fischer reagent to the nearest 0.01 mL (see Notes 7 and 9). NOTE 9--The solvent should be changed when the sample content exceeds2 g ofcrudeper 15 mL of solventor when4 mL oftitrant per ! 5 mL of solvent has been added to the titration vessel. 10.2.2 For viscous crudes, add the sample to a clean, dry dropper bottle and weigh the bottle and crude. Quickly transfer the required amount of sample to the titration vessel with the dropper. Reweigh the bottle. Titrate the sample as in 10.2.1. NOTe 10--Afteradding the sampledo not shake the cell.

12. I. 1.2 Pyridine-Free Karl Fischer Reagents: r -- 0.032 OfI/3) 9Supporting data are available from ASTM Headquarters. Request RR:D02- I 173.

A r = repeatability and R ==reproducibility.

686

~1~ D 4377 where: X = sample mean from 0.00 to 2 %. 12.2 Bias: 12.2.1 Compared to the results of Test Method D 4006, no significant bias was found. 12.2.2 The interference from mercaptan sulfur follows the theoretical stoichiometry of 1 to 0.28, that is 1000 ttg/g (ppm) of mercaptan sulfur can generate a response equivalent to 280 ttg/g (ppm) (0.03 mass %) water by this test method. The validity of correcting measured water contents for known mercaptan/sulfide sulfur levels has not been evaluated.

where: X = sample mean from 0.0 to 2 %. 12.1.2 Reproducibility--The difference between two single and independent results obtained by different operators working in different laboratories on identical test material would, in the long run, exceed the following values only in one case in twenty.

12.1.2.1 Standard Karl Fischer Reagents: R = 0.111 (XI/3) 12.1.2.2 Pyridine-Free Karl Fischer Reagents: R = 0.095 (Xi/3)

ANNEX

(MandatoryInformation) A1. HOMOGENIZATION EFFICIENCY OF UNKNOWN MIXERS A I.I The homogenization efficiency of each unknown mixer must be evaluated before use. The grade of crude oil, the sample size, and the sample container expected to be used with the mixer should be used in this test. The specifications of this test should be met before running this method and any changes in the mixing procedure should be re-evaluated by this test. The crude oil used in this test should be dry (less than 0.1% water). " AI.2 Weigh the sample container to the nearest' 0.01 g. Fill the container half way (or the level normally used) with the dry crude. Immerse the mixer into the crude with the bottom of the mixer 5 mm above the bottom of the container and mix the crude at the speed and for the amount of time you expect to use. Suggested mixing time is between 1 and 5 min at 5 to 7 thousand rpms. Immediately determine the water content in duplicate (10. l) of the dry crude. Obtain the average of the duplicate results. AI.3 Weigh the crude and container to the nearest 0.01 g. Immerse the mixer into the crude as in A 1.2. Knowing the weight of the crude, add enough water to increase the water content 1% above the base level found in AI.2. From a

water filled syringe previously weighed (nearest 0.1 mg), inject the water below the surface of the crude near the inlet to the mixer. Reweigh the syringe (to the nearest 0.1 mg) and determine the amount of water added. Wipe any oil on the needle off before weighing. Mix the sample in the same manner as in AI.2. Determine the water content of the crude immediately after mixing. Sample the crade just below the liquid level. AI.4 Without additionally mixing the crude, determine the water content of the crude 15 and 30 min after the initial mixing in AI.3. A1.5 Remix the sample in the same manner as AI.2. Immediately after mixing, determine the water content in duplicate. AI.6 The water contents of the crude determined in A1.3, AI.4, and AI.5 minus the base determined in Section AI.2 should agree within 0.05 % absolute of the added water and to each other. If they do not agree, this test should be repeated while changing the mixing time, the mixing speed, or the height of the mixer, in the crude or a combination thereof, until these conditions are met.

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in thls standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, ere entirely their own responsibility. This standard is subject to revision at any time by the responsible teChnical committee and must be reviewed every five years and ff not revised, either reepproved or withdrawn. Yourcomments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments wal receive careful consideration at a meeting of the responsible technical committee, which you may attend. If you feel that your comments have not recalved a fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103.

687

Designation:D 4419-90 (Reapproved 1 9 9 5 ) E1

An American Nat6onal Standard

Standard Test Method for Measurement of Transition Temperatures of Petroleum Waxes by Differential Scanning Calorimetry (DSC) 1 This standard is issued under the fixed designation D 4419; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (¢) indicates an editorial change since the last revision or reapproval. o NotE--Section 15 was added editorially in June 1995.

1. Scope

DSC and heat-flux DSC, call be distinguished depending o11 the method of measurement used. For additional background information refer to Practice E472, Terminology E 473, and Test Method E 474.

I. l This test method measures the transition temperatures of petroleum waxes, including microerystalline waxes, by differential scanning calorimetry (DSC). These transitions may occur as a solid-solid transition or as a solid-liquid transition. 1.2 The normal operating temperature range extends from 15"C to 150"C (Note l). 1.3 This standard does not purport to address all of the

4. Summary of Test Method 4.1 Separate samples of petroleum wax and a reference material or blank (empty sample container) are heated at a controlled rate in an inert atmosphere. A sensor continuously monitors the difference in heat flow to the two samples. The DSC curve is a record of this difference versus temperature. A transition in the wax involves the absorption of energy relative to the reference, resulting in an endothermic peak in the DSC curve. While the transition occurs over the temperature range spanned by the base of the peak, the temperature associated with the peak apex is designated the nominal transition temperature (Note I).

safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to eslablish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 1.4 The values stated in SI units are to be regarded as the standard. 2. Referenced Documents

NOTE l - - T e s t Method D 87 also monitors energy transfer between wax and a standard environment. The highest temperature DSC transition may differ from the melting point because the two methods approach the solid/liquid phase transition from different directions.

2.1 A S T M Standards: D 87 Test Method for Melting Point of Petroleum Wax (Cooling Curve) 2 D 1160 Test Method for Distillation of Petroleum Products at Reduced Pressures 2 D3418 Test Method for Transition Temperatures of Polymers by Thermal Analysis 3 E 472 Practice for Reporting Thermoanalytical Data 4 E 473 Terminology Relating to Thermal Analysis 4 E 474 Test Method for Evaluation of Temperature Scale for Differential Thermal Analysis 5

5. Significance and Use 5.1 DSC in a convenient and rapid method for determining the temperature limits within which a wax undergoes during transitions. The highest temperature transition is a solid-liquid transition associated with complete melting; it can guide the choice of wax storage and application temperatures. The solid-solid temperature transition is related to the properties of the solid, that is, hardness and blocking temperature.

3. Terminology

NOTE 2 - - F o r a relatively narrow cut petroleum wax, the lowest

3.1 Description of Term Specific to This Standard." 3.1.1 Differential Scanning Calorimetry (DSC)--A tech-

transition will be a solid-solid transition. A narrow cut wax is one obtained by deoiling a single petroleum distillate with a maximum range of 120°F between its 5 % and 95 % vol in accordance with Test Method D 1160 boiling points (converted to 760 ton'). The DSC method cannot differentiate between solid-liquid and solid-solid transitions. Such information must be predetermined by other techniques. In the case of blends, the lower temperature transition may be envelopes of both solid-liquid and solid-solid transitions.

nique in which the difference in energy inputs into a substance and a reference material is measured as a function of temperature, while the substance and a reference material are subjected to a controlled temperature program. The record is the DSC curve. Two modes, power-compensation

5.2 Since petroleum wax is a mixture of hydrocarbons with different molecular weights, its transitions occur over a temperature range. This range is one factor that influences the width, expressed in °C, of the DSC peaks. The highest temperature transition is a first-order transition. If, for a series of waxes, there is supporting evidence that the highest temperature transition of each wax is the major first-order transition, its relative width should correlate with the relative

This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.10.0A on Physical and Chemical Properties. Current edition approved May 25, 1990. Published July 1990. Originally published as D 4419 - 84. Last previous edition D 4419 - 84. 2 Annual Book of ASTM Standards, Vol 05.01. 3 Annual Book of A S T M Standards, Vol 08.02. 4 Annual Book of ASTM Standards, Vol 14.02. Discontinued; see 1985 Annual Book of ASTM Standardv, Vol 14.02.

688

~

D 4419 10. Specimen Preparation 10.1 To ensure homogeneity, completely melt the entire sample by heating it to 10*C above the temperature at which the wax is completely molten. Using a clean eyedropper, transfer a few drops to the surface of a clean sheet of aluminum foil to form a thin wax film. Separate the wax from the foil, and break it into pieces.

width of the wax's molecular weight distribution. 6. Interferences 6.1 The test specimen must be homogeneous and representative. The small sample size (10 rag) makes these requirements particularly important. 6.2 Intimate thermal contact, sample-to-pan and panto-sensor, is essential to obtain accurate and reproducible results. 6.3 The heating rate must be the specified l0 + l*C/min. Faster or slower rates will produce a different transition temperature and transition peak width.

11. Procedure 11.1 Weigh I0 + 1 mg of the wax pieces into a sample pan, and insert the pan in the calorimeter sample compartment. NOTE 3--1ntimate thermal contact, sample-to-pan and panto-sensor, is essential. Ensure that pan bottoms are flat and also that sensor surfaceswhere pans rest are clean. If the equipment is available, it is advantageous to ensure maximum sample-to-pan thermal contact by crimping a metal cover against the pan with the sample sandwiched in between. A thermal precycle (see 10.3) improves pan contact and establishes the same thermal history for every sample.

7. Apparatus

7.1 Differential Scanning Calorimeter, operating in either power compensation or heat flux mode, capable of heating at 10 _+ l*C/min from 15"C to 150"C. Controlled cooling capability is preferred but not essential. The calorimeter must be able to record automatically the differential signal (WE or WT) versus temperature with a temperature repeatability of =1=0.5"C. If the differential record is versus time, the calorimeter must have the capability to make a simultaneous record of temperature versus time. 7.2 Sample Pans, of aluminum or other metal of high thermal conductivity, excluding copper and its alloys. 7.3 Reference Material--Glass beads, alumina powder, silicon carbide, or any material known to be unaffected by repeated heating and cooling and free from interfering transitions. The specific heat capacity of the reference should be as close as possible to that of the test material. 7.4 Recorder, capable of recording heat flow versus temperatfire.

11.2 Flush the sample compartment of the test cell with inert gas throughout the test: a flow of 10 to 50 mL/min is typical. 11.3 Perform a thermal precycle (Note 3). Heat the test cell at 10 _+ lOC/min to 20 _+ 5°C beyond the end of melting, beyond the return to the base line (Notes 4 and 5). Then cool the test cell to 15 _+ 5"C at l0 + toC/min. Hold the test cell at 15°C for 30 s. NOTE 4--During the precycle heating scan, note the height of the first thermo transition peak, and adjust instrument sensitivity so it is 50 to 95 % of full scale. NOTE 5--The exposure of the sample to high temperatures should be

minimized to prevent decomposition. Hold the maximum temperature only for the time required to prepare for cooling. 11.4 Perform and record the thermal scan of record. Heat the test cell at 10 _+ l°C/min to 20 + 5°C beyond the end of melting (Note 6). Record the DSC curve using a heating rate of 10 _+ l°C/min from 150C to 20 _+ 5°C beyond the end of melting.

8. Reagent

8.1 Nitrogen, or other dry inert gas supply for flushing the sample compartment.

NOTE 6--A cooling (solidification) scan is also possible, but the transition peak apex will be several degrees celsius lower than that obtained using a heating scan.

9. Calibration 9.1 Using the instrument manufacturer's recommended procedure, calibrate the instrument's temperature scale over the temperature range of interest with appropriate standards. These include, but are not limited to:

12. Calculation 12.1 Several transitions may be present. Number them consecutively in order of appearance. Draw tangents to each transition peak (see Fig 1). The transition peak apex (TA) is located by the intersection of the tangents to the peak slopes (Notes 7 and 8).

Melting Point Standard 99 % Purity Min.

"C

K

Phenoxybenzene(2)4 p-Nitrotoluene (3) Naphthalene (4) Benzoic Acid^ Adipic Acid (5) Indium Metal (2)

26.9 51.5 80.3 122.4 153.0 156.6

300.0 324.8 353.6 395.7 426.3

NOTE 7--The extrapolated onset (T o) and end (TL) temperatures are located by the intersection of the peak tangents with the base line (see

Fig l). The difference between the onset and end temperatures of each transition peak is a measure of peak width. NOTE 8--Some microcrystallinewaxes may exhibit shoulders on the transition peaks. If this occurs, exclude the shoulder in drawing in the extrapolated onset (To) and end (T~:)temperatures.

429.9

^See Test Method D3418. 99.98 % purity available from U.S. Bureau of Standards as SRM 350.

9.2 The specimen weight and test procedure should be those specified in Section 10, except that the precycle (l 1.3) is omitted.

12.2 Read the temperature associated wittt each transition peak apex from the curve, and apply any correction indicated by the temperature-scale calibration. 13. Report 13.1 Report the corrected apex and end temperatures for

6 The boldface numbers in parentheses refer to the list of references at the end of this test method.

689

~

D 4419 14.1.1 Repeatability--The difference between successive test results, obtained by the same operator with the same apparatus under constant operating conditions on identical test material, would, in the long run, in the normal and correct operation of the test method, exceed the following values only in one case in twenty:

c

•TIo

8-

T2E

TIE ~ T 2 0

-t / TIA

First-Order

- T2A - T20

End

- T2E

Second

Order-Transltlon:

Apex Onset

- TIA - TIO

End

- TIE

I

FIG. 1

0.8 1.0

(1.4) (1.8)

Apex, TtA

1.2

(2.2)

End, TI~

1,4

(2.5)

Solid-Liquid Transition Temperatures Apex, T2^ End, T2E Solid-Solid Transition Temperatures Apex, TIA End, Tie

I T2A

Temperature,

"F

14.1.2 Reproducibility--The difference between t w o single and independent results, obtained by different operators working in different laboratories on identical test material, would, in the long run, in the normal and correct operation of the test method, exceed the following values only in one case in twenty:

Transltlon:

Apex Onset

"C Solid-Liquid Transition Temperatures Apex, T2^ End, T ~ Solid-Solid Transition Temperatures

"C

"C

°F

3.5 6. I

(6.3) ( [ 1.0)

2.3 11.2

(4.1) (20.2)

NOTE 9 - - D S C will not differentiate between solid-liquid and solidsolid transitions; other techniques must be used for example, melting

Schematic of Petroleum Wax A DSC Curve (Heating Cycle)

point in accordance with Test Method D 87.

^ Sample determined to have solid-liquid and solid-solid transitions by another technique.

each of the transition peaks to the nearest 0.5"C in order of occurrence. First thermal transition apex (TIA), first thermal transition end temperature (T~E), second thermal transiton apex temperature (T2A), and second thermal transition end temperature (T2e), transition temperature of petroleum waxes by DSC.

14. Precision and Bias 14.1 Precision--The precision of this test method as obtained by statistical examination of interlaboratory test results is as follows:

14.1.3 The first thermal transition temperature precision data are based on duplication determinations on five different petroleum waxes in an interlaboratory study among six laboratories. The second thermal transition temperature precision data are based on duplicate determinations on two different petroleum waxes in an interlaboratory study among six laboratories. 14.2 Bias--The procedure in this test method has no bias because the value of transition temperatures can be defined only in terms of a test method.

15. Keywords 15.1 differential scanning calorimetry; petroleum wax; thermal properties; transition temperature

REFERENCES (1) Mackenzie, R. C., "Nomenclature in Thermal Analysis, Part IV," Journal of Thermal Analysis, 13, 1978, p. 387. (2) Rossini, F. D., Pure Applied Chemistry, Vol 22, 1970, p. 557.

(3) Timmermans and Hennant-Roland, J. Chim. Physics, Vol 34, 1937, p. 693. (4) API Project 44, Vet I, Tables 23-2-(J3.5200)A and AE. (5) Morrison, J. D. and Robertson, J. M. J. Chem. Soc. London, 1949, p. 987.

The American Society for Testing and Materials takes no position respecting the vafidity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reepproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103.

690

( ~ T ~ Designation: D 4423 - 91

An American National Standard

Standard Test Method for Determination of Carbonyls In C 4 Hydrocarbons 1 This standard is issued under the fixed designation D 4423; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsdon (0 indicates an editorial change since the last revision or reapproval.

polymerization reactions, the presence of carbonyls in excess over some specified amount can have a deleterious effect upon the polymer properties or the reaction itself, or both.

1. Scope 1.1 This test method covers the determination of carbonyls (ketones and aldehydes) in C4 hydrocarbons. This test method was tested on polymerization-grade 1,3butadiene. 1.2 The applicable range for this test method is 0 to 50 mg/kg carbonyls calculated as acetaldehyde. 1.3 Other C4 hydrocarbons and their mixtures besides polymerization-grade 1,3-butadiene could be tested using this same test method. However, the precision section of this test method covers only carbonyls in applicable range as listed in 1.2, as found in polymerization-grade 1,3-butadiene. 1.4 The values stated in SI units are to be regarded as the standard. 1.5 This standard does not purport to address all of the

5. Apparatus

5.1 Bunsen Valves--A device constructed so that when used with an Erlenmeyer flask, the sample vapors can exit the flask while protecting the flask's liquid contents. See Fig. 1 for details. 5.2 Cooling Coil--Prepare a cooling coil by winding about 10 to 15 cm of seamless copper tubing (about 6-mm diameter) on a short length of pipe (about 1.5 to 2.0-cm diameter), allowing sufficient length of tubing at the end of the coil to connect it to the sample source. Attach a valve at a point that would not extend more than 8 cm above the surface of the cooling bath liquid. To the valve, attach a 6 to 8 cm length piece of tubing bent downward so that the hydrocarbon liquid can be directed into the receiving container. 5.3 Dewar Flask--The Dewar flask must be of sufficient volume to completely immerse the main portion of the cooling coil except for the extremities necessary for receiving and delivering the sample through the coil. 5.4 Erlemneyer Flasks. 250-mL capacity. 5.5 Volumetric Flasks. 1-L capacity. These flasks should be Class A glassware. 5.6 Graduated Cylinders--lOO-mL capacity, glass cylinders, graduated in 1 or 2-mL divisions. 5.7 Microburets. 2.00 or 5.00-mL capacity. The microburets should be Class A glassware with 0.01 or 0.02-mL divisions or less. It is advisable to have the buret's tip end equipped with a syringe needle to dispense very small drops of titrant. 5.8 Sample Cylinders--These should be of sufficient volume to give the required amount of sample for testing. Stainless steel cylinders equipped with needle valves should be used. It is suggested that a 500-mL-capacity cylinder be the minumum size to be used for butadiene. 5.9 ThermometermFor observing temperatures below -45"C. The Low Cloud and Pour Point Thermometer, conforming to the requirements for ASTM Thermometer 6C, as prescribed in Specification E I, is satisfactory. Thermometer 6C has a range from - 8 0 to +20"C.

safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 2. Referenced Documents

2.1 ASTM Standards: D484 Specification for Hydrocarbon Dry Cleaning Solvents2 D 1193 Specification for Reagent Water 3 E 1 Specification for ASTM Thermometers 4

3. Summary of Test Method 3.1 A measured amount of sample is added to an alcoholic hydroxylamine hydrochloride solution that has been adjusted to a given coloration using either alcoholic acid or base. The carbonyls will react with the hydroxylamine hydrochloride releasing an equivalent amount of hydrochloric acid which is then back-titrated to the original coloration. A blank containing only methanol and sample is titrated and the sample's results are calculated using the blank adjustment. Results are reported as milligrams per kilogram carbonyls as acetaldehyde. 4. Significance and Use 4.1 The determination of the carbonyl content of polymerization-grade 1,3-butadiene is necessary, since in some J This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct "responsibility of Subcommittee D02.D on Hydrocarbons for Chemical and Special Uses. Current edition approved March 15, 1991. Published July 1991. Originally published as D 4423 - 84. Last previous edition D 4423 - 84. 2 Discontinued; see 1983 Annual Book of ASTM Standards, Vol. 05.01. 3 Amnzal Book of ASTM Standards, Vol I 1.01 4 Annual Book of ASTM Standards, Vol 14.03.

6. Reagents and Materials 6.1 Purity of Reagents--Reagent grade chemicals should be used in all tests. Unless otherwise indicated, it is intended that all reagents conform to the specifications of the Committee on Analytical Reagents of the American Chemical 691

(~) D 4423 6.7 Stoddard Solvent--Conforming to the specification listed in Specification D 484. (Warning--See Note 6.)

USE A MOHRPINCHCOCK CLAMP HERE

NOTE 6: Warning--Combustible. Vapor harmful. RUBBERTUBING

VI

b m

-

~

L

I

T

6.8 Thymol Bhw Indicator--Dissolve 0.04 g of thymol blue in 100 mL of anhydrous methanol. (Warning--See Note 3.)

IN

-

RUBBER TUBING

7. Preparation of Apparatus 7.1 Dry Ice-Stoddard Solvent Bath--Add a sufficient quantity of Stoddard solvent into the Dewar flask to ensure that the cooling coil will be submerged in the liquid plus dry ice (solid CO2). (Warning--See Notes 5 and 6.) Carefully add sufficient dry ice to the Stoddard solvent to obtain a temperature of at least -500C. (WarningmSee Note 7.) Attach the sample cylinder containing the butadiene (Warning--See Note 8.) to the cooling coil and immerse the coil into the liquid. Support the sample cylinder in a cylinder rack or using a ring stand and appropriate clamps. Be sure the coil is positioned so that the delivery tip is free to dispense liquid butadiene into the Erlenmeyer flasks. After each use, be sure to clean the coil's interior with methanol. DO NOT USE ACETONE.

GLASS TUBING

RUBBER STOPPER

FIG. 1

Apparatus

Society where such specifications are available? Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination. 6.2 Purity of WatermUnless otherwise indicated, references to water shall be understood to mean Type II reagent water conforming to Specification D 1193. 6.3 Alcoholic Hydrochloric Acid (0.05 N)--Dilute 4.2 mL of concentrated hydrochloric acid (Warning--See Note 1) to volume with anhydrous methanol in a 1-L volumetric flask. Use the alcoholic 0.05 N potassium hydroxide solution to standarize the HCI solution.

NOTE 7: Warning--Great care must be taken during this step. Do not add the dry ice all at once, but in small pieces, especially at the beginning. Wear protective gloves and adequate eye protection to prevent any contact with the extremely cold materials. NOTE 8: Warning--Extremely flammable gas under pressure. May form explosive peroxides upon exposure to air. Harmful if inhaled. Irritating to eyes, skin, and mucous membranes.

NOTE 1: Warning--Poison Corrosive. May be Ihtal d" swallowed. Liquid and vapor cause severe burns. Harmful if inhaled.

6.4 Alcoholic Hydroxylamine Hydrochh)ride--Dissolve 35.0 g of hydroxylamine hydrochloride (Warning--See Note 2) in 3.5 L of anhydrous methanol. (Warning--See Note 3.) NOTE 2: Warning--May be irritating to skin, eyes, or mucous

membranes. Harmful if inhaled. NOTE 3: Warning--Flammable. Vapor harmful. May bc fatal or cause blindness if swallowed or inhaled. Cannot be made nonpoisonous. 6.5 Alcoholic Potassium Hydroxide (0.05 N)--Dissolve 3.3 g of potassium hydroxide in anhydrous methanol. (Warning--See Note 4.) Make to volume with methanol in a I-L volumetric flask. Standardize against a primary standard, potassium acid phthalate. NOTE 4: Warning--Corrosive. Can cause severe burns or blindness. Evolution of heat produces a violent reaction or eruption upon too rapid mixture with water. 6.6 Dry Ice (Carbon Dioxide Solid)--(Warning--See Note 5.) NOTE 5: Warning--Extremely cold (-78.5°C). Liberates heavy gas which may cause suffocation. Contact with skin causes burns or

freezing, or both. Vapors may react violently with hot magnesium or aluminum alloys. Reagent Chemicals, American Chemical Society Specifications, "Am. Chemical Soc.", Washington, DC. For suggestions on the testing of reagents not listed by the American Chemical Society, see "Reagent Chemicals and Standards," by Joseph Rosin, D. Van Nostrand Co., Inc., New York, NY, and the "United States Pharmacopeia."

692

8. Procedure 8. l Prepare a sample flask by pouring 50 mL of alcoholic hydroxylamine hydrochloride into a 250-mL Erlenmeyer flask. 8.2 Prepare a flask for use as a sample blank by pouring 50 mL of methanol into a 250-mL Erlenmeyer flask. 8.3 Add about 0.5 mL of thymol blue indicator solution to each flask. 8.4 Carefully add 0.05 N alcoholic KOH or alcoholic HC1 to each flask until matching colors are obtained. The desired color is a yellow color with a slight, but distinct, orange coloration. It is important that this orange color is present at this point of the test. If the color is more yellow at this point, it would be easy to obtain a result of less than 1 mg/kg carbonyls on a sample containing over 100 mg/kg of carbonyls. 8.5 Stopper the flasks with the Bunsen valves. (This keeps the COz vapor out of the flasks). Set the flasks on some crushed dry ice for a few minutes to cool the liquid contents. The color in the flasks may turn more yellow when cold, but this is not significant at this point. From this step forward, all operations must be carried out in a well-ventilated hood. 8.6 Cool a 100-mL graduated cylinder by holding it in the cooling bath for a few seconds. Then, when it is cold, collect 100 ___ 1 mL butadiene into the graduated cylinder. Quickly, using a clean thermometer, measure the sample's temperature to the nearest I*C. Record this temperature as "T" for use later to obtain the sample weight. Pour this sample into the sample flask containing the alcoholic hydroxylamine hydrochloride solution. Replace the Bunsen valve on the flask and set aside. Again, collect 100 ___ I mL of sample into

(@) D 4423 the graduated cylinder. Pour this sample into the sample blank flask containing only the methanol. Replace the Bunsen valve and set aside. 8.7 Sample and sample blank can be titrated after 15 min while cold butadiene is in the flasks. If done, be careful to avoid vigorous agitation because some of the contents may boil over and be lost. It is advisable to allow as much of the butadiene as possible to evaporate before titration begins. 8.8 Titrate the sample flask's contents back to the original coloration, as described in 8.4, by using the alcoholic KOH. Record this value as "A." Set the flask aside in the hood for 5 min before pouring out the contents. If it turns red, the carbonyl concentration may be high or there is contamination in the flask. Continue the titration until the flask's contents will not turn red after standing 5 minutes. 8.9 Titrate the sample blank flask's contents. If the solution is red, use the standard KOH solution. If it is yellow, use the standard HC1 solution. In either case, unless the sample blank's contents are still at the original coloration, titrate with the appropriate titrant back to the same, original coloration as described in 8.4. Record this value as "E."

TABLE 1

Density of Butadiene at Various Temperatures

NOTE--These data may be used Jn a graphical manner for better interpolation between data points. Temperature, °C

Density. g/mL

-45 -40 -35 -30 -25 -20 -15 -10 -5 0

0.6958 0.6903 0.6848 0.6793 0.6737 0.6681 0.6625 0.6568 0.6510 0.6452

where: Na = normality of alcoholic HCI Ba = alcoholic HC1 used for the sample blank, mL

10. Precision and Bias 10.1 Precision--The precision of this test method as determined by statistical examination of interlaboratory results is as follows: 10.1.1 R e p e a t a b i l i t y - - T h e difference between two test results obtained by the same operator with the same apparatus under constant operating conditions on identical test material would, in the long run, in normal and correct operation of the test method, exceed the following value in only one case in twenty, where X = the average of the two test results:

9. Calculation 9.1 Calculate as follows when the sample has no free acid or free base: mg/Kg carbonyls (as acetaldehyde) (1) = A × Nb x 44050/V x D

where: A --- alcoholic KOH titration, mL, Nb = normality of KOH solution, V = sample volume, mL, and D = butadiene density at temperature T (found by using Table 1).

14 % of X

10.3 Reproducibility--The difference between two single and independent results obtained by different operators working in different laboratories on identical test material would, in the long run, in the normal and correct operation of the test method, exceed the following value in only one case in twenty, where X = average of two test results: 88 % of X

9.2 Calculate as follows when the sample has free acid: mg/Kg carbonyls (as acetaldehyde) (2) = (A - Bb) × Nb × 44050/V × D where Bb = alcoholic KOH used for the sample blank, mL.

10.4 B i a s - - S i n c e there is no accepted reference material for determining the bias for the procedure in this test method for measuring carbonyls, no statement on bias is being made.

9.3 Calculate as follows when the sample has free base: mg/Kg carbonyls (as acetaldehyde) (3) = ((.4 × Nb) + (Ba x Na)) × 44050/V × D

11. Keywords 11.1 butadiene; C 4 hydrocarbons; carbonyls; titration

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend. /f you fee/that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103.

693

~]~

Designation: D 4 4 2 4 - 90

An American National Standar0

Standard Test Method for Butylene Analysis by Gas Chromatography 1 This standard is issued under the fixed designation D 4424; the number immediately following the designation indicates the year of

original adoption or, in the case of revisiort, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (E) indicates an editorial change since the last revision or reapproval.

1. Scope 1.1 This test method covers the gas chromatographic analysis of commercial butylenes, butylene concentrates, and butane-butylene mixtures. 1.2 This test method does not cover high-purity butene-I or high-purity isobutene streams, or both. However, it is possible that one or more columns listed in Appendix X 1 may be capable of the separation necessary for high-purity analyses. 1.3 This test method is designed to cover the components listed below at about 0.05 % or greater. It is not intended for trace hydrocarbon analysis. Components to be determined are: propane, propylene, isobutane, n-butane, butene-l, isobutene, trans-butene-2, cis-butene-2, 1,3-butadiene, isopentane, n-pentane. 1.4 The values stated in S 1 units are to be regarded as the standard. The values stated in inch-pound units are for information only.

1.5 This standard does not purport to address all of the safety problems associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific warning statements, see

Notes I and 2. 2. Referenced Document 2.1 ASTM Standard: E 260 Practice for Packed Column Gas Chromatography2

3. Summary of Test Method 3.1 The sample is separated in a gas chromatograph system using a packed chromatographic column with either helium or hydrogen as the carder gas. The separated components of the sample are detected by either a thermal conductivity detector or by a flame ionization detector. Calibration data are obtained by using either relative response factors or by using a standard calibration blend.

4. Significance and Use 4.1 This test method could be used to determine butylene stream composition for custody transfer payments. It is also capable of providing data necessary to evaluate processing requirements in an operating plant. t This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.D on Hydrocarbons for Chemical and Special Uses. Current edition approved Sept. 28, 1990. Published November 1990. Originally published as D 4424 - 84. Last previous edition D 4424 - 84. 2 Annual Book of ASTM Standards, Vol 14.01.

694

5. Apparatus 5.1 Chromatograph--Any chromatographic instrument having either a thermal conductivity or flame ionization detector with an overall sensitivity sufficient to detect at least 0.05 % of each of the components listed in the scope. 5.2 Detector--Either a thermal conductivity or flame ionization detector may be used. 5.3 Sample Valve--Either a constant-volume gas sampiing valve or a liquid sampling valve may be used. If a gas sampling valve is used, greater care must be taken to ensure that the vaporized butylenes that are injected into the chromatograph are a true representation of the sample. 5.3.1 If the liquid sample valve is used, the sample cylinder must be pressured up to at least 1100 kPa (160 psig) with an inert gas, such as nitrogen or helium (Warning--See Note 1). Also a valve must be installed in the purge line downstream of the liquid sample valve to ensure the butylenes sample in the sampling valve is entirely in the liquid phase prior to injection into the column (Warning-see Note 2). 5.4 Column--Any chromatographic column may be used, providing the components listed in the scope can be separated sufficiently for the accurate determination of component concentration. Resolution between peaks must afford a resolution such that the depth of the valleys between peaks are no less than 50 % of the peak height of the lesser component. A list of satisfactory columns is given in Appendix X 1. 5.5 Recorder--A recorder with a full-scale response of 2 s or less and a maximum rate of noise of +0.3 % of full scale.

NOTE I: Warning--Compressedgas under high pressure. Gas reduces oxygenavailablefor breathing. NOTE 2: Warning--Extremelyflammableliquefiedgas under pressure. Vapor reduces oxygenavailablefor breathing. 6. Preparation of Apparatus 6.1 Set up the chromatograph in accordance with the manufacturer's recommendations. Install the analytical column and adjust the carrier gas flow and column temperature so that the components will elute within the time desired for the analysis.

7. Calibration 7.1 A standard blend containing the components to be analyzed may be either made or purchased from a commercial source. Inject the calibration blend under identical conditions as will be used for the samples. Record the chromatogram and calculate the factors to be used for analysis by using the peak areas as measured by either manual, mechanical, or electronic means.

D 4424 7.2 Relative response factors may be used if they are available.

Measurement may be automatic by using either mechanical or electronic integrators or computers.

NOTE 3--Practice E 260 procedures may be helpful to those using this test method.

9. Calculations 9.1 Calculate the concentration of each component using the following equation:

8. Procedure 8.1 If a vapor sample is to be injected using a gas sample valve, a representative portion of the liquid butylenes must be taken and vaporized into a suitable container. As a suggestion, a small, 5 or 10 mL aliquot of liquid butylenes under pressure in a valved, 5 or 10-mL sample cylinder can be expanded into a larger container as a vapor. Then this resultant vapor would be injected into the chromatograph. 8.2 If a liquid sampling valve is used, pressure the sample cylinder to at least 1100 kPa (160 psig) with either helium or nitrogen. 8.3 Take the sample after the proper preparation has been done and inject it into the gas chromatographic column using the appropriate sampling valve. Record the chromatogram using as low an attenuation as possible to insure all peaks are on scale and as large as possible. 8.4 Measure the peak areas after all peaks have eluted.

Ci =

(,41 X F,

X

100/ZA,

X

F,)

where: C~ Ai Fl • Ai × Fl

= concentration of the i-th component, ffi peak area of the i-th component, ffi calibration factor for the i-th component, and = sum of all products of peak areas times calibration factors. 10. Precision and Bias 10.1 The precision section shall be developed after cooperative interlaboratory study program. 10.2 B/asmSince there is no accepted reference material suitable for determining bias for the procedure in this test method, bias cannot be determined. 11. Keywords 11.1 butylene; cl-c4 hydrocarbons; gas chromatography

APPENDIX (Nonmandatory Information) Xl. SUGGESTED COLUMNS

Column 12.2 m by 3.2-mm (40 ft by l/s-in.) outside diameter stainless steel packed with 16 % sebaconitrile on 80/100 mesh AW Chromosorb P; followed by 1.8 m by 3.2-mm (6 ft by Va-in.) outside diameter stainless steel packed with 80/100 mesh OPN/Porasil C Durapak; followed by 1.2 m by 3.2-mm (4 fl by I/,-in.) outside diameter stainless steel packed with 80/100 mesh phenylisocyanate on Porasil C Durapak. Carrier Gas, hydrogen at 30 cm3/min. Column Oven Temperature, 40"C. Sample Valve, l-~tL liquid valve.

X 1.1 Column A. Column 2.1 m by 3.2-mm (7 ft by Va-in.) outside diameter steel packed with 20 % diisopropyl phthalate on 60/80 mesh NAW Chromosorb P; followed by 15.2 m by 3.2-ram (50 ft by Vs-in.) outside diameter stainless steel packed with 20 % dimethyl sulfolane on 60/80 mesh NAW Chromosorb P. Carrier Gas, helium at 30 cm3/min. Column Oven Temperature, ambient. Sample Valve, l-ttL liquid valve. XI.2 Column B.

The American $colety for Testing and Matariais takes no poaitico reepeeting the validity of any potent rights a~erted In connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of Infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must he reviewed every five years end if not revised, either reepprovedor withdrawn. Your comments are Invited either for revlaico of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful con.sidaratlon at a meeting of the responsible technical committee, which you may attend, ff you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103.

695

q~)

Designation: D 4492 - 96

Standard Test Method for Analysis of Benzene by Gas Chromatography 1 This standard is issued under the fixed designation D 4492; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (0 indicates an editorial change since the last revision or reapproval.

3. Summary of Test Method 3.1 A known amount of an internal standard is added to the specimen. A small volume of this mixture is injected into a gas chromatograph equipped with a flame ionization detector (FID) and a capillary column. 3.2 The peak area of each impurity and the internal standard is measured by an electronic integrator. The concentration of each impurity is calculated from the ratio of the peak area of the internal standard versus the peak area of the impurity. Purity is calculated by subtracting the sum of the impurities found from 100.00 weight %. Results are reported in weight percent.

1. Scope 1.1 This test method covers the determination of normally occurring trace impurities in, and the purity of, finished benzene by gas chromatography. 1.2 This test method was judged applicable for nonaromatic impurities at levels from 0.001 to 0.200 weight % and for benzene purities of 99.80 weight % or higher. 1.3 This test method is applicable for aromatic impurities from 0.001 to 0.010 weight % in benzene. 1.4 The following applies to all specified limits in this standard: for purposes of determining conformance with this standard, an observed value or a calculated value shall be rounded off "to the nearest unit" in the last fight-hand digit used in expressing the specification limit in accordance with the rounding-off method of Practice E 29. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements, see Section 8.

4. Significance and Use 4.1 This test method is suitable for determining the concentrations of known impurities in finished benzene and for use as an integral quality control tool where benzene is either produced or used in a manufacturing procedure. It is generally applied to impurities such as nonaromatics containing nine carbons or less, toluene, C8 aromatics, and 1, 4-dioxane. 4.2 Absolute purity cannot be determined if unknown impurities are present. Test Method D 852 is generally used as a criteria for determining the absolute purity.

2. Referenced Documents

5. Interferences 5.1 Benzene is typically resolved from naturally occurring components with boiling points <1380C. Naturally occurring components include nonaromatic hydrocarbons, toluene, C8 aromatics, and 1, 4-dioxane. An adequate separation of known impurities from benzene should be evaluated for the column selected. 5.2 The internal standard chosen must be sufficiently resolved from any impurity and the benzene peak.

2.1 A S T M Standards: D 852 Test Method for Solidification Point of Benzene 2 D 3437 Practice for Sampling and Handling Liquid Cyclic Products2 E 29 Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications 3 E 260 Practice for Packed Column Gas Chromatographya E 355 Practice for Gas Chromatography Terms and Relationships3 E 691 Practice for Conducting an Interlaboratory Test Program to Determine the Precision of Test Methodsa E 1510 Practice for Installing Fused Silica Open Tubular Capillary Columns in Gas Chromatographs3 2.2 Other Document: OSHA Regulations. 29 CFR, paragraphs 1910.1000 and 1910.12004

6. Apparatus 6.1 Gas Chromatograph--Any chromatograph having a

TABLE 1 TypicalInstrumentalParameters Detector Column:

Length Inside diameter

Stationary phase Film thickness Temperatures: Injector Detector Column Carder gas:

This test method is under the jurisdiction of ASTM Committee D-16 on Aromatic Hydrocarbons and Related Chemicals and is the direct responsibility of Subcommittee DI6.0A on Benzene, Toluene, Xylenes, Cyclohexane, and Their Derivatives. Current edition approved Jan. 10, 1996. Published March 1996. Originally published as D 4492 - 85. Last previous edition D 4492 - 95. 2 Annual Book of A S T M Standards, Vol 06.04. 3 Annual Book of A S T M Standards, Vol 14.02. 4 Available from Superintendent of Documents, U.S. Government Printing Office, Washington DC 20402.

Une~ velocity

Sp,t ratio:

Samitesize Recorder

696

flame ionization fused silica 50 m 0.32 mm crossllnked polyethylene glyco~ 0.25 lun 200°C 2500C 700C isothermal helium 22 crn/s 200:1 0.5 ~L electronic integration required

({~ D 4492 TABLE 2

flame ionization detector that can be operated at the conditions given in Table 1. The system should have sufficient sensitivity to obtain a minimum peak height response for a 0.0005 weight % impurity twice the height of the signal background noise. 6.2 Electronic Integrator, computer-based capable of handling internal standard calculations and peak grouping is recommended. 6.3 Column, fused silica capillary column with crosslinked polyethylene glycol stationary phase is recommended. Alternate stationary phases may be used if they produce at least the same aromatic separation and elute C9 nonaromatic impurities before benzene. 6.4 Microsyringes, 10 and 100/al capacity.

7. Reagents and Materials 7.1 Carrier GasmChromatographic grade helium is recommended. 7.2 High Purity Benzene, 99.99 weight % minimum, prepared by multiple step recrystallization of commercially available 99 + weight % benzene. 7.3 Internal Standard, n-Nonane (nCg) with a purity of 99 weight % minimum is recommended. Other compounds may be acceptable provided they can be obtained in high purity and meet the requirements of 5.2. 7.4 Pure compounds for calibration should include toluene, benzene, ethylbenzene, cyclohexane, and 1, 4-dioxane of a purity not less than 99 %. If the purity of the calibration compounds is less than 99 %, the concentration and identification of impurities must be known so that the composition of the final weighed blends can be adjusted for the presence of the impurities.

Typical Calibration Blend, g

Benzene Toluene

99.0000 0.0500 0.0500 0.0500 0.0200

Cyclohexane Ethylbenzene 1, 4 Dloxane

the weight % concentration of the calibration blend. 11.3 Into a 50-mL volumetric flask, add 50 [tL of nC9 to 49.95 mL of the calibration blend and mix well. Using a density of 0.874 g/mL for the calibration blend and a density of 0.718 g/mL for the nC9, the resulting nC9 concentration will be 0.0825 weight %. 11.4 Inject 0.5 ktL of the blend with internal standard into the chromatograph and integrate the area under each peak, excluding benzene. 11.5 Calculate the relative response factors (RRF) as follows: l~,~& =

(ap(CN( C,)(AI)

where:

RRF, As -4 i

c, c,

= = = = =

RRF for impurity i, peak area of internal standard, peak area of impurity i, weight % for impurity i, from 11.2, concentration of internal standard, weight % from 11.3.

12. Procedure 12.1 Into a 50-mL volumetric flask, add 50 p.L of nC9 internal standard and dilute to the mark with specimen. Mix well. 12.2 Inject 0.5 IxL of mixture into the chromatograph. 12.3 Integrate the area under all peaks except for benzene. Sum the nonaromatic fraction up to nC9 for reporting as a single component. See Fig. 1 for a typical chromatogram.

8. Hazards 8.1 Consult current OSHA regulations and supplier's Material Safety Data Sheets and local regulations for all materials used in this test method. 8.2 Benzene is considered a hazardous material. The sampling and testing of benzene should follow safety rules in order to adhere to all safety precautions as outlined in current OSHA regulations.

13. Calculation 13.1 Calculate the amounts of each individual impurity as required. Sum the areas of all the nonaromatic peaks. 13.2 Calculate the weight % concentration of each impurity as follows: c, = (.4,)(RRF,)(C~)IC.4.) 13.3 Calculate the benzene purity as follows: Benzene, weight % = 100.00 - Ct where: Ct = total concentration of all impurities, weight %. 14. Report 14.1 Report the following information: 14.1.1 Benzene and the total impurities to the nearest 0.01%, and 14.1.2 Individual impurities to the nearest 0.001%.

9. Sampling 9.1 Sample the material in accordance with Practice D 3437. 10. Preparation of Apparatus 10.1 Follow manufacturer's instructions for mounting the column into the chromatograph and adjusting the instrument to the conditions described in Table 1. Allow sufficient time for the equipment to reach equilibrium. See Practices E 260, E 1510 and E 355 for additional information on gas chromatography practices and terminology.

15. Precision and Bias s 15.1 Precision--The following criteria should be used to judge the acceptability of results obtained by this test method (95 % confidence level). The precision criteria was derived from the round-robin data submitted by six different laboratories. Each sample was run twice in two days by two

II. Calibration 11.1 Prepare a synthetic mixture of high purity benzene and representative impurities by direct weighing. Weigh each impurity to the nearest 0.1 mg. Table 2 contains a typical calibration blend. Cyclohexane is used for the nonaromatic portion and ethylbenzene for the Cs aromatic portion. 11.2 Using the exact weight for each impurity, calculate

s Supporting data are available from ASTM Headquarters. Request RR: DI6-1005.

697

q~) D 4492 .c E

m

.g

.2

=o

z

o

~J

p,

5417

c o (J

\ 1465 1"

2

3"

4 Tin, e

FIG. 1

S

b

(mln)

Typical Chromatogram

different operators. Results of the round robin data were analyzed in accordance with Practice E 691. 1, 4 Dioxane results are derived from limited data (nine analyses by one operator in a single laboratory). 15.2 Intermediate PrecisionmDuplicated results by the same operator should not be considered suspect unless they differ by more than _+ the amount shown in Table 3. 15.3 Reproducibility--The results between two laboratories should not be considered suspect unless they differ by more than + the amount shown in Table 3. 15.4 Bias--Since there was no accepted reference material available at the time of interlaboratory testing, no statement on bias can be made at this time.

TABLE 3

Benzene Purity Intermediate Precision and Reproducibility

Concentrauon(mg/kg) Component Nonaromatlcs Toluene Ethylbenzene

p-Xylene m-Xylene o-Xylone

16. Keywords

1, 4 DIoxane

16.1 benzene; gas chromatography; purity

Average IntermediateReproducibility Concentration Precision 22

19

20

737

70

184

14 116 14 121 13 110 44 162 14 89 168 6

2 4 3 7 3 5 5 9 5 7 12 2

6 54 7 14 5 16 9 17 18 8 ...

Benzene(wt ~;) 99.99

698

0.002

0,004

~

D 4492

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and ff not revised, either reepproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend, ff you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 100 Barr Harbor Drive, West Conshohockan, PA 19428.

699

~]~

Designation: D 4530 - 93

An American National Standard

Standard Test Method for Determination of Carbon Residue (Micro Method) 1 This standard is issued under the fixed designation D 4530; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last rcapprovai. A superscript epsilon (0 indicates an editorial change since the last revision or reapproval.

D 482 Test Method for Ash from Petroleum Products 3 D 4046 Test Method for Alkyl Nitrate in Diesel Fuels by Spectrophotometry4 D4057 Practice for Manual Sampling of Petroleum and Petroleum Products 4

1. Scope 1.1 This test method covers the determination of the amount of carbon residue (Note 1) formed after evaporation and pyrolysis of petroleum materials under certain conditions and is intended to provide some indication of the relative coke forming tendency of such materials. 1.2 The test results are equivalent to the Conradson Carbon Residue test (Test Method D 189).

3. Terminology 3.1 Definition: 3.1. I carbon residue, n--in petroleum products, the part remaining after a sample has been subjected to thermal decomposition. 3.1.1.1 DiscussionmThe amount of residue is dependent on the test conditions of evaporation and pyrolysis. The term may be misleading here in that the residue may contain other than carbon decomposition products. However, the term is retained due to its wide common usage.

NOTE I - - T h i s procedure is a modification o f the original m e t h o d

and apparatus for carbon residue of petroleum materials, where it has been demonstrated that thermogravimetry is another applicable technique.2 Howeverit is the responsibilityof the operator to establish operating conditions to obtain equivalent results when using thermogravimetry. 1.3 This test method is applicable to petroleum products that partially decompose on distillation at atmospheric pressure and was tested for carbon residue values of 0.10 to 30 % (m/m). Samples expected to be below 0.10 weight % residue should be distilled to remove 90 % of the flask charge (see Section 9 in Test Method D 189 for details). The 10 % bottoms remaining is then tested for carbon residue by this test method. 1.4 Ash-forming constituents as defined by Test Method D 482, or non-volatile additives present in the sample will add to the carbon residue value and be included as part of the total carbon residue value reported. 1.5 Also in diesel fuel the presence of aikyl nitrates, such as amyl nitrate, hexyl nitrate or octyl nitrate, causes a higher carbon residue value than observed in untreated fuel, which may lead to erroneous conclusions as to the coke-forming propensity of the fuel. The presence of aikyl nitrate in the fuel may be detected by Test Method D 4046. 1.6 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety practices and to determine the applicability of regulatory limitations prior to use. For specific hazard statements see Notes 5, 6, 7, and 8.

4. Summary of Test Method 4.1 A weighed quantity of sample is placed in a glass vial and heated to 500"C under an inert (nitrogen) atmosphere in a controlled manner for a specific time. The sample undergoes coking reactions and volatiles formed are swept away by the nitrogen. The carbonaceous-type residue remaining is reported as a percent of the original sample as "carbon residue (micro)." 5. Significance and Use 5.1 The carbon residue value of the various petroleum materials serves as an approximation of the tendency of the material to form carbonaceous type deposits under degradation conditions similar to those used in the test method, and can be useful as a guide in manufacture of certain stocks. However, care needs to be exercised in interpreting the results. 5.2 This test method offers advantages of better control of test conditions, smaller samples, and less operator attention compared to Test Method D 189 to which it is equivalent. 5.3 Up to twelve samples may be run simultaneously including a control sample.

2. Referenced Documents

6. Apparatus 6.1 Glass Sample Vials, 2-mL capacity, 12-mm outside diameter by approximately 35 mm high. 6.2 Eyedropper or Small Rod, for sample transfer. 6.3 Coking Oven 5 with circular heating chamber approximately 85 mm (3-3/8 in.) diameter by 100 mm (4 in.) deep,

2.1 A S T M Standards: D 189 Test Method for Conradson Carbon Residue of Petroleum Products 3 This test method is under the jurisdiction of ASTM Committee I)-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.06 on Analysis of Lubricants. Current edition approved April 15, 1993. Published June 1993. Originally published as D 4530 - 85. Last previous edition D 4530 - 85. 2 See Fuel, Vol 63, July 1984, pp. 931-934. 3 Annual Book of ASTM Standards, Vol 05.0 I.

4 Annual Book of ASTM Standards, Volume 05.03. 5 A satisfactory oven with associated automatic controls that performs this carbon residue test is available from ALCOR, INC., 10130 Jones-Maitsberger Road, San Antonio, TX 78216. This commercial unit is known as the MCRT.

700

~)

D 4530

30 psig).

for top loading, with heating capability of 10 to 40"C]min rate to 500"C, with exhaust port 13 mm (1/, in.) inside diameter for nitrogen purge of oven chamber (inlet near top, exhaust at bottom center) with thermocouple sensor located in oven chamber next to but not touching sample vials, with lid capable of sealing out air, and with removable condensate trap located at the oven chamber base. A schematic diagram is given in Fig. 1. 6.4 Sample Vial Holder--Cylindrical aluminum block approximately 76 mm (3 in.) diameter by 16 mm (5/8 in.) thick with twelve evenly=spaced holes (for vials) each 13 mm 0/' in.) diameter by 13 mm (I/2 in.) deep. The holes are arranged in a circular pattern approximately 3 mm ('/8 in.) from the perimeter. The holder has legs 6 mm (m/4in.) long, with guides to center in oven chamber, and an index mark on the side to use as position reference. The sample vial holder is shown in Fig. 2. 6.5 Thermocouple,suitable for controller and temperature range of interest, with exterior temperature readout, degrees Celsius. 6.6 Analytical Balance, with +0.1 mg sensitivity to 20 g minimum weighing capacity. 6.7 Cylinder of Zero Grade Nitrogen (Industrial), with 2-stage regulator, for delivery pressure of 0 to 200 kPa (0 to

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304 STAINLESSSTEEL TOP PLUG. ROUNO

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I

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7. Procedure 7.1 Sample Preparation: 7.1.1 Obtain weights of clean sample vials (1 to 12 per batch), and record the mass to nearest 0.1 mg. 7.1.2 During weighing and filling, handle vials with forceps to help minimize weighing errors. Discard the sample vials after use. 7.1.3 It is assumed that a representative sample of the stock or process has been obtained for laboratory use following Practice D 4057 or similar method, and that the laboratory has received a sample of about a gallon or less. Stir the sample to be tested, first warming if necessary to reduce its viscosity. Samples that are homogeneous liquids can be transferred directly to vials using a rod or syringe. Solid materials may also be heated; or frozen with liquid nitrogen, then shattered to provide manageable pieces. 7.1.4 Transfer an appropriate weight of the sample (Table 1) into a tared-sample vial, reweigh to nearest 0.1 mg and record. Place the loaded sample vials into vial holder (up to twelve), noting position of each sample with respect to index mark.

I i h

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304 STAINLESS STEEL (1.6mm) INNER CYLINORICAL SHELL OUTER CYLINDRICAL SHELL ~THERMOCOUPLE LEADS

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MICROPROCESSOR CONTROLLER

FIG. 1

J

Coking Oven and Lid

701

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D 4530

VIAL HOI' DER o

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FIG. 2

TABLE 1 Samp/eDescription Black, viscousor solid Brown, viscous Lute ell consistencyand appearance,or 10 ~; bottoms

~ 0 40ram

Sample Vial Holder and Vial

Guide for Sample Size

ExpectedCarbon Residue,(mlm),% >5 1-5 <1

S'rA,NLESSSTEEL

nitrogen purge m a y be shut off. Recommended SampleSize,g 0.15 ± 0.05 0.5 ± 0.1 1.5 ± 0.5

NOTe 4--To reduce oven temperature for the next run, remove the oven lid to allow faster fooling. As required by the procedure, the subsequent test can be started when the oven has been cooled to below 100"C. NOTE 5: Caution--Do not open oven to air at any time during the heating cycle. The introduction of air (oxygen) will likely cause the sample to ignite and spoil the test. (Because of the oven design and materials, such an ignition is normally not a hazard to the operator.) Open the oven only after oven temperature falls below 250"C during the cooling step. Maintain nitrogen flow until after the vial holder has been removed from the oven. NOTE 6: Precaution--Locate the coking oven in laboratory exhaust hood for safe venting of smoke and fumes. Alternatively, install vent line from MCRT oven exhaust to laboratory exhaust system. NOTE 7: Caution--If a vent line is used, do not connect directly to exhaust chimney to avoid creating negative pressure in the line.

NOTE 2--A control sample can be included in each batch of samples being tested. This control sample should be a typical sample that has been tested at least 20 times in the same equipment in order to define an average percent carbon residue and standard deviation. Results for each batch are deemed acceptable when results for the control sample fall within the average percent carbon residue :t: three standard deviations. Control results, which are outside these limits, indicate problems with the procedure or the equipment. 7.2 Processingof Samples: 7.2.1 With the oven at less than 100°C, place the vial holder into the oven chamber and secure lid. Purge with nitrogen for at least 10 rain at 600 m L / m i n . Then decrease the purge to 150 m L / m i n and heat the oven slowly to 500°C at 10 °- 15"C/rain. 7.2.2 If the sample foams or spatters causing loss o f sample, discard and repeat the test.

7.3 Final Weighing--Transfer sample vials (maintained in place in the vial holder) to desiccator and allow vials to cool to r o o m temperature. Weigh the cooled vials to the nearest 0.1 mg and record. Handle the vials with forceps. Discard the used glass sample vials. 7.4 Occasionally examine the condensate trap at the b o t t o m o f the oven chamber; empty if necessary and replace. NOTE 8: Warning--The condensate trap residue may have some carcinogenic materials present. Avoid contact with the trap residue; dispose of it in accordance with local laboratory practice.

NOTE 3--Spattering may be due to water that can be removed by prior gentle heating in a vacuum followed by a nitrogen sweep. Alternatively, a smaller sample size can be used.

8. Calculation

7.2.3 Hold oven at 500 +_ 2"C for 15 rain. Then shut off furnace power and allow oven to cool freely while under nitrogen purge o f 600 m L / m i n . W h e n oven temperature is less than 250"C, remove the vial holder for further cooling in desiccator. After the samples are removed from the oven, the

8.1 Calculate the mass percent carbon residue in the original sample, or in the 10 % distillation bottoms as follows: 8.1.1 Calculate percent residue as follows: 702

~1~) D 4530 I

I

R • (% CARBON RESXIXJ~')

2/3

r = (% CARBON RESZ~J~)

X 0.2451 X 0.0770

^nucIBILITY=

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(~.~

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I I

REPEATABILITY

(r)

f f

0

I0

5

15

20

25

30

CARBON RESIDME, AVERAGE %

FIG. 3

Carbon Residue (Micro) Precision Data

10. Precision and Bias6 10.1 The precision of this test method as determined by

(Note 9) statistical examination of inteflaboratory results is as follows: NOTE 9--Prec/sion data and Conradson carbon residue/micro carbon residuecorrelationdata were generatedby a task forcein 1983. The round robin involved 18 laboratories, six petroleum materials in duplicate analysisfor both micro methodand Test MethodD 189 tests. Range of values for sampleswas from 0.3 % to 26 %. 10.2 Repeatability--The difference between two test results, obtained by the same operator with the same apparatus under constant operating conditions on identical test material would, in the long run, in the normal and correct operation of the test method, exceed the values shown in Fig. 3 only in one case in twenty. 10.3 Reproducibility--The difference between two single and independent results obtained by different operators working in different laboratories on identical test material would, in the long run, in the normal and correct operation of the test method, exceed the values shown in Fig. 3 only in one case in twenty. 10.4 Bias--The procedure in Test Method D4530 for measuring carbon residue of petroleum by the carbon residue method has no bias because the mass percent of carbon residue can be defined only in terms of the test method.

6 Supporting data are available from ASTM Headquarters. Request RR:D021192.

11. Keywords 11.1 carbon residue; carbon residue (micro method); diesel fuel; lubricating oil; petroleum products

% carbon residue = (A × 100) w

(l)

where: A = carbon residue (7.3.1), g, and W = sample used (7.1.4), g. 8.1.2 Calculate the percent carbon residue in the orginal sample, when using 10 % distillation bottoms as follows (see Test Method D 189 for details): % residue in original sample ffi (~ × 100) x E

(2)

where: A ffi carbon residue, g C = 10 % bottoms used, g, and E = final weight flask charge/original weight flask charge. 9. Report 9.1 Report the value obtained as carbon residue, micro method, to the nearest 0.1% (m/m).

703

~ ) D 4530

APPENDIX

Nonmandatory Information Xl. CORRELATION AND OTHER METHODS X l. I A correlation (see Fig. 4) has been derived between the carbon residue test by the micro method and the Conradson carbon residue test (Test Method D 189) in a cooperative program involving 18 laboratories and six petroleum materials. X 1,2 Statistical analysis using modified Student's t tests

and nonparametric analysis show that, considering the precisions of both tests, there is no difference between the two methods. The data generated by the carbon residue test by the micro method are statistically equivalent to the Conradson carbon residue test except for better precision in the micro method residue test.

30

,J ,.f r

10

J

./

O/•

10

15

20

25

30

NICRO C/~BO~ R£SII)UF, ( t BY MASS}

FIG. 4 Correlation of Conradlon and Carbon Residue (Micro)Tos~ The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, ere entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and ff not revised, either reapproved or withdrawn. Your comments ere invited either for revision of this etanderd or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103.

704

(~1~) Designation: D 4534 - 89 (Reapproved 1993) ~1

Standard Test Method for Benzene Content of Cyclic Products by Gas Chromatography I This standard is issued under the fixed designation D 4534; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year oflast revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (0 indicates an editorial change since the last revision or re.approval. El NOT£--Keywords were added editorially in July 1993.

inspections, process control, establishing specifications, and research work.

1. Scope 1.1 This test method covers the determination of the benzene content of specific cyclic hydrocarbon products. 1.2 Benzene may be determined over a range from 5 to 300 mg/kg. 1.3 The products in which benzene can be determined include cyclohexane, toluene, individual Cg aromatics, cumene, and styrene. 1.4 This standard does not purport to address all of the

5. Apparatus 5.1 Gas Chromatograph--Any chromatograph having either a flame ionization or other detector that is capable of providing a minimum peak height response of 0.1 mV for 20 mg/kg benzene using a maximum sample injection of 2 IxL. 5.2 Chromatographic ColumnmThe choice of column is based on resolution requirements. Any column may be used if it is capable of resolving benzene from the major component and other impurities. The column described in Table 1 has been found satisfactory. 5.3 IntegratormElectronic integration is recommended. 5.4 Recorder, Strip Chart, 0 to 1-mV range recording potentiometer with a response time of 1 s or less and maximum noise level of 0.3 % of full scale. If electronic integration is not used, a minimum chart width of 200 mm and a minimum chart speed of 1 cm/min is required. 5.5 Microsyringe, 10-1xLcapacity. 5.6 Volumetric Flask, 50-mL capacity.

safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. A specific hazard statement is given in Section 7.

2. Referenced Documents

2.1 A S T M Standards: D 3437 Practice for Sampling and Handling Liquid Cyclic Products2 E 260 Practice for Packed Column Gas Chromatography3 E 355 Practice for Gas Chromatography Terms and Relationships3 2.2 Other Document: OSHA Regulations, 29 CFR, paragraphs 1910.1000 and 1910.12004

6. Reagents and Materials 6.1 Carrier Gas, helium or nitrogen, chromatographic grade. 6.2 Hydrogen, zero grade. 6.3 Compressed Air, oil free. 6.4 Benzene, 99 % minimum purity. 6.5 Specific Cyclic Hydrocarbon, high-purity (best grade obtainable) benzene content not to exceed I 0 % of the level expected in the sample.

3. Summary of Test Method 3.1 A gas chromatograph with a flame ionization or other detector and a column containing a supported polar liquid phase is used. A reproducible volume of sample is injected. Quantitative results are obtained from the measured area of the recorded benzene peak by using a factor obtained from the analysis of a blend of known benzene content.

7. Hazards 7.1 Consult current OSHA regulations and supplier's TABLE 1

4. Significance and Use 4.1 Knowledge of the benzene content is typically required for cyclic products used as chemical intermediates and solvents. This test method may be used for final product

Detector Column Length Outside diameter Stationary phase Support Temperature, °C Sample inlet system Column Detector Carder gas Flow rate Sample size

This test method is under the jurisdiction of ASTM Committee I:)-16 on Aromatic Hydrocarbons and Related Chemicals and is the direct responsibility of Subcommittee DI6.0E on Instrumental Analysis. Current edition approved Nov. 24, 1989. Published January 1990. Originally published as D 4534 - 85. Last previous edition D 4534 - 85. 2 Annual Book of ASTM Standards, Vol 06.04. 3 Annual Book of ASTM Standards, Vol 14.02. 4 Available from Superintendent of Documents, U.S. Government Printing Office, Washington, DC 20402.

instrument Parameters Hydrogen flame ionization Copper 3.7 m (12 ft) 3.175 mm (Ya in.) TCEPE (Tetracyanoethylated pentaerythritol), 10 Chromosorb p,A 60-80 mesh 200 75-85 a 200 Helium or nitrogen 20 rnL/minA 0.5-2 p.L, reproducible

A Chromosorb P is a registered trademark of Johns-Manville Corp. n Approximate values, see 10.1.

705

(~ D 4534 TABLE 2

TABLE 3

Density of Cyclic Hydrocarbons at 15.56°C, g/mL Benzene Cumene Cyclohexane Styrene Toluene

0.8838 0.8655 0.7826 0.9102 0.8711

Major Component

Precision

Benzene C o n c e n t r a t i o n , Repeatability, mg/kg mg/kg

Reasonable Range, mg/kg

Cumene Cumene Cumene

5 27 222

1 2 19

0-11 22-33 206-256

Material Safety Data Sheets for all materials used in this test method.

Cyclohexane Cyclohexane Cyclohexane

64 86 277

4 5 28

35-90 55-115 244-310

8. Sampling 8.1 Guidelines for taking samples from bulk are given in Practice D 3437.

Styrene Styrene Styrene

15 38 204

2 6 11

0-35 25-67 120-250

Toluene Toluene

20 190

2 16

14-23 147-206

9. Calibration 9.1 Prepare a calibration blend or blends of benzene in the specific cyclic hydrocarbon at the level or levels approximating those in the samples to be analyzed. A separate blend must be made for each specific cyclic hydrocarbon. 9.2 Calculate the benzene content of the calibration blend using the following equation and the densities listed in Table 2.

shorten the retention time of these components. If this is done, the column must be reequilibrated at the analysis temperature before each subsequent analysis.

10.3 Measure the area of the benzene peak. Units must be consistent with 9.4. 11. Calculation l I. 1 Calculate the concentration of benzene in mg/kg in the cyclic hydrocarbon using the following equation: Benzene, mg/kg = AB/(C - D)

Benzene, mg/kg = (BI)(B2) (Sj)(S2) (10 3) where: B 1 = density of benzene, B 2 = volume of benzene added to the cyclic hydrocarbon, IxL, $1 = density of cyclic hydrocarbon, and $2 = volume of cyclic hydrocarbon, mL. 9.3 For example, to prepare an 81-mg/kg blend of benzene in toluene, fill a 50-mL volumetric flask to the mark with high-purity toluene. With a microsyringe, carefully add 4.0 ~tL of benzene to the toluene and mix well. 9.4 Analyze both the blend and the pure cyclic hydrocarbon used to prepare the blend as described in Section 10. Subtract the area of the benzene found in the pure cyclic hydrocarbon from the area of the benzene in the blend to determine the area represented by the concentration of benzene added to the blend, as shown in 1 I. 1.

where: A = area of benzene peak in the sample, B = concentration of benzene added to the blend. Important: Blend must be made in the same cyclic hydrocarbon as is being analyzed as the sample, C = area of benzene peak in the blend, and D = area of benzene in the pure cyclic hydrocarbon. 12. Report 12.1 Report the concentration of benzene in the sample on an absolute basis to the nearest 1 mg/kg. 13. Precision and Bias 5 13.1 The following criteria should be used to judge the acceptability (95 % probability level) of results obtained by this method. The criteria were derived from a round robin among five laboratories. 13.1.1 RepeatabilitymResults in the same laboratory should not be considered suspect, unless they differ by more than the amount shown in Table 3. 13.1.2 Reproducibilitymlt is estimated that results on the same sample run in two laboratories should be considered suspect if they differ by more than the reasonable range shown in Table 3. Because of the round-robin results from this method, these values were taken straight from the research report without statistical reduction.

10. Procedure 10.1 Install the chromatographic column, and establish stable instrument operation at the proper operating conditions as shown in Table 1. AdJust column temperature and flow rate to achieve sufficient resolution. A retention time of 5 to 6 min for benzene has been found to yield sufficient resolution with the recommended column. Refer to instructions provided by the manufacturer of the chromatograph and to Practices E 260 and E 355. 10.2 Inject a repeatable volume of sample, typically 2 IxL or less, into the chromatograph. The volume of sample injected must be exactly the same as the volume of blend injected. Start the recorder or integration device, or both, and obtain the chromatogram.

14. Keywords 14.1 bentene; cumene; cyclohexane; cyclic products; gas chromatography; styrene; toluene

NOTEmSome samples may contain components significantly heavier than benzene that may have a long retention time. If desired, the column temperature may be raised after the elution of benzene to

5 Supporting data are available from ASTM Headquarters. Request RR: D16-1006.

706

~

O 4534

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are express/), advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reepproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend, ff you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103.

707

({~

Designation: D 4628 - 96a

An American National Standard

Standard Test Method for Analysis of Barium, Calcium, Magnesium, and Zinc In Unused Lubricating Oils By Atomic Absorption Spectrometry 1 This standard is issued under the fixed designation D 4628; the number immediately following the designation indicates the year of original adoption or, in the case &revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (0 indicates an editorial change since the last revision or reapproval.

This test method has been approved for use by agencies of the Department of Defense. Consult the DoD Index of Specifications and Standards for the spec07cyear of issue which has been adopted by the Department of Defense.

1. Scope 1.1 This test method is applicable for the determination of mass percent barium from 0.005 to 1.0 %, calcium and magnesium from 0.002 to 0.3 %, and zinc from 0.002 to 0.2 % in lubricating oils. 1.2 Higher concentrations can be determined by appropriate dilution. Lower concentrations of metals such as barium, calcium, magnesium, and zinc at about 10 ppm level can also be determined by this test method (Note 1).

NOTE 3: W a r n i n g - - H a z a r d o u s . Potentially toxic and explosive.

4. Significance and Use 4.1 Some oils are formulated with metal-containing addifives that act as detergents, antioxidants, antiwear agents, etc. Some of these additives contain one or more of these metals: barium, calcium, zinc, and magnesium. This test method provides a means of determining the concentration of these metals that gives an indication of the additive content in these oils.

NOTE l - - U s e o f this test m e t h o d for the determination at these lower concentrations should be by agreement between the buyer and the seller.

1.3 Lubricating oils that contain viscosity index improvers may give low results when calibrations are performed using standards that do not contain viscosity index improvers. 1.4 The values stated in SI units are to be regarded as the standard. 1.5 This standard does not purport to address all of the

5. Apparatus 5.1 Atomic Absorption Spectrophotometer. 5.2 Analytical Balance. 5.3 Automatic Measuring Pipet or Volumetric Class A Pipet, 50-mL capacity. 5.4 Bottles with Screw Caps, 60 mL (2 oz).

safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Specific precau-

NOTE 4--Suitable volumetric flasksor plastic bottles may be substituted. 5.5 Shaker, Mechanical Stirrer, or Ultrasonic Bath, capable of handling 60-mL bottles.

tionary statements are given in Notes 1, 2, 6, and 8.

2. Referenced Document 6. Reagents 6.1 Base Oil, metal-free, with a viscosity of about 4 cSt at t00"C. A 100 neutral oil which provides good solvency for standards and additive concentrate is satisfactory. Highly paraffinic oils should be avoided. 6.2 2.Ethyl Hexanoic Acid, which has been determined to be free of interfering metals. 6.3 Kerosine, Metal-Free (Note 4)--(See Notes 5, 6, and Warning Note 7), distillation range from 170°C to 2800C at 100 kPa (1 atm). When the kerosine solvent is contaminated, it may be purified metal-free by running through attapulgus clay.

2.1 A S T M Standard: D 1319 Test Method for Hydrocarbon Types in Liquid Petroleum Products by Fluorescent Indicator Adsorpfion 2

3. Summary of Test Method 3.1 A sample is weighed and base oil is added to 0.25 + 0.01-g total mass. Fifty mililitres of a kerosine solution, containing potassium as an ionization suppressant, are added, and the sample and oil are dissolved. (WarningmSee Note 1.) Standards are similarly prepared, always adding oil if necessary to yield a total mass of 0.25 g. These solutions are burned in the flame of an atomic absorption spectrophotometer. An acetylene/nitrous oxide flame is used. (WarningmSee Note 2.)

NOTE 5--Solvents other than kerosene, such as xylene MEK and so forth, may be used in this test method, however, the precision data quoted in Section 16 was obtained using kerosene. NOTE 6--Metal-free kerosine can be obtained from most laboratory supply houses, but should be tested for metal content before using. NOTE 7--Satisfactory results have been obtained in this test method by using Baker "kerosine"(deodorized)which has typical initial and end boiling points of 191"Cand 240"C, respectively,and a typical composition of 96.7 volume % saturates, 0.1 volume % olefins,and a maximum of 3.2 volume % aromatics. If the kerosine used by an operator deviates appreciably from this composition, there may be significanterror. NOTE 8: Warning---Combustible.Vapor harmful.

NOTE 2: Warning--Combustible. Vapor harmful.

This test method is under the jurisdiction of ASTM Committee D-2 on Petm|eum Products and Lubricants and is the direct responsibility of Subcommittee 1302.03 on Elemental Analysis. Current edition approved Dec. 10, 1996. Published February 1997. Originally published as D 4628 - 86. Last previous edition D 4628 - 96. 2 Annual Book of ASTM Standards, Vol 05.01.

708

118]~ D 4828 Barium K Ionization Suppressant in Kerosine Solvent

0.5-

(¢

0.4

/

0.3-

0.2.

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/

/

l

/

0.1-

o%

5o0

1600

2060

30bO

C o n c e n t r a t i o n o f K i n ppm

FIG. 1

Plot Graphlfor Badumand Calcium

minimum concentration of potassium needed is that above the knee for both the barium and calcium curves.

6.4 Oil-Soluble Metal Compounds,3 stock standard blend in base oil. A 0.25 4- 0.01-g portion of this stock standard blend diluted with 50 m L of the potassium ionization suppressant solution (see 6.5) shall yield a reading of 0.5 + 0.1 absorbance units for each of the elements barium, calcium, magnesium, and zinc using a minimum of scale expansion or burner rotation. The concentrations of the metal should be blended accurately to three significant figures. The actual concentrations should be chosen to conform to the optimum working range of the particular instrument being used, but as a guide one cooperator used 0.4 % barium, 0.03 % calcium, 0.03 % magnesium, and 0.06 % zinc. The stock standard blend should be heated and stirred to ensure a homogeneous solution. Note 9--In addition to the calibration standards identified in 6.4, single-element or multielement calibration standards may also be prepared from materials similar to the samples being analyzed, provided the calibration standards to be used have previously been characterized by independent, primary (for example, gravimetric or volumetric), and analytical techniques to establish the elemental concentration mass percent levels. 6.5 Potassium Ionization Suppressant Solution containing an oil-soluble potassium compound in kerosine at 2.0 4- 0.1 g potassium/litre of solution. NOtE IO--The actual potassium concentration needed varies with the source of potassium and perhaps the instrumental conditions as well. To determine the needed concentration, atomize solutions containing 0, 500, 1000, 1500, 2000, 2500, and 3000 ppm potassium with 25 ppm barium and 5 ppm calcium in each. Plot graphs of barium and calcium absorbance versus potassium concentration as shown in Fig. 1. The

6.6 Working Standards--Freshly prepared by weighing into six 60-mL bottles (1) 0.25, (2) 0.20, (3) 0.15, (4) 0.10, (5) 0.05, and (6) 0 g of stock standard blend (see 6.4) to three significant figures and add 0.0, 0.05, 0.10, 0.15, 0.20, and 0.25 4- 0.01 g of base oil, respectively. Add 50 m L of potassium ionization suppressant solution (see 6.5) to each bottle and shake or stir to dissolve. NOTE I l--Many modern AAS instruments can store up to 3 or 4 calibration standards in memory. In such cases, follow the manufacturer's instructions, ensuring that the unknown sample's ahsorbance is in the linear part of the calibration range used.

7. Preparation of Apparatus 7.1 Consult the manufacturer's instructions for the operation of the atomic absorption spectrophotometer. The present test method assumes that good operating procedures are followed. Design differences between spectrophotometers make it impractical to specify the required manipulations in detail here. NOTe 12: Warning--Proper operating procedures are required for safety as well as for reliability of results. An explosion can result from flame blow-back unless the correct burner head and operating sequence are used. 7.2 For the barium determination, fit the barium hollow cathode lamp and set the monochromator at 553.6 nm. Make fine adjustments to the wavelength setting to give maximum output. Using the correct burner head for acetylene/nitrous oxide, set up the acetylene/nitrous oxide flame. On instruments where applicable, adjust the gain control to

s Oil soluble metal compounds found satisfactory for this method are available from National Institute of Standards and Technology, Office of Standard Reference Materials, Washington, DC 20234.

709

~ D 4628 set this maximum at full scale, when aspirating standard (6) in 6.6. 7.3 Aspirate at about 2.5 to 3 mL/min a standard barium solution into the flame. Make adjustments to the height and angle of the burner and to the acetylene flow rate to give maximum absorption. Make sure that standard (6) in 6.6 still gives zero absorbance by making adjustments, if necessary.

multiplying the found results by 1.005. If the sample remains hazy, the sample is not suitable to be analyzed by this test method. 10.2 Samples yielding absorbances greater than 0.5 even with the minimum sample size can be accurately diluted with new base oil to a suitable concentration. Make sure the new solution is homogeneous before proceeding as instructed in I0.I. 10.3 Aspirate the sample solution and determine the absorbance, aspirating solvent alone before and after each reading.

8. Calibration (Barium) 8.1 Aspirate standard (I) in 6.6. With a minimum of scale expansion or burner rotation, obtain a reading of 0.5 + 0.1 on the absorbance meter or alternative read-out device. 8.2 Aspirate the standards of 6.6 sequentially into the flame and record the output (or note the meter deflections). Aspirate the solvent alone after each standard. 8.3 Determine the net absorbance of each standard. If the spectrophotometer output is linear in absorbance, the net absorbance is given by the difference between the absorbance for the standard or sample solution and the absorbance for the solvent alone. If the speetrophotometer output is proportional to transmission (that is, to light intensity) then the net absorbance is given by loglo do~dr, where the deflections are do when solvent alone is aspirated and d, when the standard or sample solution is aspirated. 8.4 Plot the net absorbance against the concentration (mg/50 mL suppressant solution) of barium in the standards to give a calibration curve. NOTE 13--The calibration curve may be automatically calculated by

11. Calculation (Barium) 11.1 Read from the calibration curve the concentration, C, corresponding to the measured absorbance. C ffi concentration of barium in the diluted sample solution, rag/50 mL of suppressant solution. 11.2 Calculate the barium content of the oils in percent mass as follows:

(t)

Barium, % mass ffi cD 10W where: W = grams of sample/50 mL, C ffi milligrams of metal/50 mL, and D ffi dilution factor if dilution was necessary in 10.2.

NOTe 14--If the calibration curve is linear, the concentration may be determined by an equation instead of a calibration curve.

the instrument software and displayed by way of the instrument computer terminal, making actual plotting unnecessary.

12. Calcium Determination 12.1 Repeat Sections 7, 8, 9, 10, and 11 replacing references made to barium with calcium using the following conditions: 12.1.1 Acetylene/nitrous oxide flame, 12.1.2 Calcium hollow cathode lamp, and 12.1.3 Analytical line 422.7 nm.

8.5 Calibration must be carried out prior to each group of samples to be analyzed and after any change in instrumental conditions, as variation occurs in the instrument behavior. Readings may also vary over short times from such causes as buildup of deposits on the burner slot or in the nebulizer. Thus, a single standard should be aspirated from time to time during a series of samples to cheek whether the calibration has changed (a check after every fifth sample is recommended). The visual appearance of the flame also serves as a useful check to detect changes of condition. 8.6 Determine the slope and intercept for barium based on the calibration curve developed. The values will be used to determine barium concentrations of samples to be tested. Ensure that the regression coefficent is at least 0.99 for barium, otherwise the laboratory needs to re-calibrate for barium when this criteria is not satisfied.

13. Magnesium Determination 13.1 Repeat Sections 7, 8, 9, 10, and 11 replacing references made to barium with magnesium using the following conditions: 13.1.1 Acetylene/nitrous oxide flame, 13.1.2 Magnesium hollow cathode lamp, and 13.1.3 Analytical line 285.2 nm. 14. Zinc Determination 14.1 Repeat Sections 7, 8, 9, 10, and 11 replacing references made to barium with zinc using the following conditions: 14.1.1 Acetylene/nitrous oxide flame, 14.1.2 Zinc hollow cathode lamp, and

9. Sampling 9.1 Shake the sample thoroughly before sampling to ensure obtaining a representative sample. 10. Procedure (Barium) 10.1 Weigh the sample to three significant figures into a 60-mL (2-oz) bottle. The sample mass is chosen to give an absorbance reading of 0.2 to 0.5. Add base oil to make 0.25 -+ 0.01 g total mass. Add 50 mL of potassium suppressant solution, see 6.5, and dissolve. The maximum sample size to be used is 0.25 g, and the minimum is 0.05 g. 10.l.l To hazy samples add 0.25 + 0.01 mL of 2-ethyl hexanoic acid and shake. If this clears up the haze, the analysis is run, and the dilution error is corrected by

TABLE 1

710

Repeatability

Element

Range. Mess

Repeatability

Barium Calcium Magnesium Zinc Calcium Zinc

0.005-1.0 0.002-0.3 0.002-0.3 0.002-0.2 1.7 1.0

0.0478x ~ 0.0227x q 0.0168x~ 0.0247X "~ 0.032 0.025

I@) D 4628 TABLE 2 Element Badura Calcium Magnesium Zinc Calcium Zinc

Reproducibility

TABLE 3

Range, Mass */,

Reproducibility

0.005-1.0 0.002-0.3 0.002-0.3 0.002-0.2 1.7 1.0

0,182x ~ 0.0779x"* 0.0705x "~ 0.0537X "n 0.090 0.048

Mass (x) Barium 0.01 0.05 0.10 0.50 1.0 Calcium 0.002 0.01 0.05 0.3 Magnesium 0.002 0.01 0.05 0.3 Zinc 0.002 0.01 0.05 0.20

14.1.3 Analytical line 213.9 nm. NOTE 15--Although this test method has been described for the determination of four elements on a single sample, the sequence of operations in analyzing several samples should also be considered. Aspiration of a sample to determine its absorbance is very quick. Changing wavelength setting and lamps takes longer. Thus, it is most economical to make measurements at a single wavelength on a series of samples and standards before changing conditions. 15. Report 15.1 Report concentrations greater than 0.1% to three significant figures. 15.2 Concentrations between 0.005-0.1% barium and 0.002-0.1% zinc, calcium, and magnesium are reported to two significant figures. 15.3 Concentrations less than the lower limits in 15.2 shall be reported as less than the appropriate lower limit.

Repeatability and Reproducibility Repeatability 0.0487x "~ 0.002 0.037 0.011 0.031 0.049 0.0227x "b 0.0004 0.001 0.003 0.010 0.0168x '~ 0.0003 0.001 0.032 0.008 0.0247x "~ 0.0004 0.001 0.003 0.008

Reproducibility 0.182x 4. 0.008 0.025 0.039 0.115 0.182 0.077gx ~ 0.0012 0.004 0.011 0.035 0.0705x '* 0.011 0.003 0.009 0.032 0.0537x "~ 0.0009 0.032 0.007 0.018

NOTE 16--The values of these precision estimates for selected values of x are set out in Table 3. NoTe 17--The precision data in Section 16 was obtained by using samples containing higher concentration levelsof metals and may not be representative of the precision at about l0 ppm concentration levels. 16.2 Bias: 16.2.1 No bias statement can be written because of the lack of suitable reference materials of known composition. 16.2.2 The presence of certain viscosity index improvers can cause a negative bias for one or more elements. In interlaboratory studies, this bias was found to be small relative to the reproducibility of this test method, and the bias was minimized by using smaller sample sizes (for example, a sample size o f 0.050 g of a blended oil) for oils that contain viscosity index improvers.

16. Precision and Bias 16.1 The precision o f this test method as determined by statistical examination of interlaboratory results is as follows: 16.1.1 Repeatability---The difference between the two test results, obtained by the same operator with the same apparatus under constant operating conditions on identical test material, would, in the long run, in the normal and correct operation of this test method, exceed the values in Table 1 only in one case in twenty. 16.1.2 ReproducibilitymThe difference between two single and independent results obtained by different operators working in different laboratories on identical test materials would, in the long run, in the normal and correct operation of this test method, exceed the values in Table 2 only in one case in twenty.

17. Keywords 17.1 additive elements; atomic absorption spectrometry; barium; calcium; lubricating oils; magnesium; zinc

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned In this standard, Users of this standard are expressly advised that determination of the validity of any such patent rights, end the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and ff not revised, either reepproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 100 Barr Harbor Drive, West Conshohockan, PA 19428.

711

~]~

Designation: D 4629 - 96

I P ,~,,, Designation: 379/88 , J l i,t ~ . , .

o*~t

Standard Test Method for Trace Nitrogen in Liquid Petroleum Hydrocarbons by Syringe/Inlet Oxidative Combustion and Chemiluminescence Detection 1 This standard is issued under the fixed designation D 4629; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (~) indicates an editorial change since the last revision or reapproval.

1.

Scope

1.1 This test method covers the determination of the trace total nitrogen naturally found in liquid hydrocarbons boiling in the range from approximately 50"C to 400"C, with viscosities between approximately 0.2 and 10 cSt (mm2/s) at room temperature. This test method is applicable to naphthas, distillates, and oils containing 0.3 to 100 mg/kg total nitrogen. 1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. See Sections 5.2, 5.4, 5.5, 5.10, and 6.0. 1.3 The values stated in acceptable SI units are to be regarded as the standard.

2. Summary of Test Method 2.1 The sample of liquid petroleum hydrocarbon is injected into a stream of inert gas (helium or argon). The sample is vaporized and carried to a high temperature zone where oxygen is introduced and organic and bound nitrogen is converted to nitric oxide (NO). The NO contacts ozone and is converted to excited nitrogen oxide (NO2). The light emitted as the excited N O 2 decays is detected by a photomultiplier tube and the resulting signal is a measure of the nitrogen contained in the sample.

3. Significance and Use 3.1 Some process catalysts used in petroleum and chemical refining may be poisoned when even trace amounts of nitrogenous materials are contained in the feedstocks. This test method can be used to determine bound nitrogen in process feeds and may also be used to control nitrogen i This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.03.0B on Spectrometric Methods. Current edition approved Apr. 10, 1996. Published June 1996. Originally published as D 4629 - 86. Last previous edition D 4629 - 91 (1995) el. 2 The apparatus described in (4.1 through 4.11) is manufactured in several variations by the Antek Instruments Inc. of Houston, TX and Dohrmann Division, Xertex Corp. of Santa Clara, CA. Both have been found to meet all essential requirements.

712

compounds in finished products which fall within the scope of the test method.

4. Apparatus~ (Figs. 1, 2, and 3) 4.1 Furnace, electric, held at a temperature sufficient to volatilize and pyrolyze all of the sample and oxidize the organically bound nitrogen to NO. Furnace temperature(s) for petroleum substances shall be as recommended by the manufacturer. 4.2 Combustion Tube, fabricated from quartz. The inlet end of the tube holds a septum for syringe entry of the sample and has a side arm for introduction of oxygen (02) and inert gas. The construction is such that the inert gas sweeps the inlet zone transporting all of the volatilized sample into a high temperature oxidation zone. The oxidation section shall be large enough (see Figs. 1 and 3) to ensure complete oxidation of the sample. Figures 1 and 3 depict conventional pyrolysis tubes. Other configurations are acceptable if precision is not degraded. 4.3 Drier TubeDThe reaction products include water vapor that must be eliminated prior to measurement by the detector. This can be accomplished with a magnesium perchlorate Mg(C104): scrubber or a membrane drying tube (permeation drier), or both. 4.4 Chemiluminescent Detector, capable of measuring light emitted from the reaction between NO and ozone. 4.5 Totalizer, having variable attenuation, and capable of measuring, amplifying and integrating the current from the chemiluminescent detector. The amplified or integrated output signal shall be applied to a digital display and to strip chart recorder if desired. 4.6 Microlitre Syringe, of 5, 10, 25, 50, or 250 ~tL capacity capable of accurately delivering microlitre quantities is required. The needle should be long enough to reach the hottest portion of inlet section furnace when injecting the sample. 4.7 Recorder (Optional). 4.8 Constant Rate Injector System (Optional), capable of delivering a sample at a precisely controlled rate may have independent signal processing and data display capabilities (optional). 4.9 Boat Inlet System (Optional), to facilitate analysis of samples that would react with the syringe or syringe needle. Pyrolysis tube for boat inlet use may require specific con-

~

O 4629

The manufacturer of thls pyrolysis tube configuratlon recommends use of a quartz insert tube packed wlth CuO.

9 miI

l

02 INLET PORT

D

He It/LET PORT

J

/"

_.. 230 mm

I _,

19 mm 1 .D.

I~

410 mm

-

FIG. 1

(. . . .

I

Quartz Pyrolysis Tube

DIGITAL 1 DISPLAY

I I

SYRINGE __ __

FURNACE

INLET

ZONE

CARRIER - HELIUH

..

I

o

oN

I GEN~AT°~ FIG. 2

I

L ....

F

o~,GE~

Typical Instrument Block Diagram

440 mm 350 mm 18/9 BALL

1

25 mm

BURNERTIP AND SEPTUMDETAIL ii

ID must f i t 12 mmSEPTUM

i

50 ~n

I-

IO0 mm

....

FIG. 3

2 mm

= ~

25 n~

Quartz Pyrolysis Tube

ll~rl~ D 4629 7. Sampling 7.1 To preserve volatile components, which may be in some samples, do not uncover samples any longer than necessary. Analyze samples as soon as possible after taking from the bulk supplies to prevent loss of nitrogen or contamination due to exposure or contact with sample container.

struction permitting insertion of a boat fully into the inlet furnace section. 4.10 Outlet End of Pyrolysis Tube (Optional), may be constructed to hold a removable quartz insert tube. 4.11 Quartz Insert Tube (Optional) (Fig. 1), may be packed with cupric oxide (CuO) which may aid in completing oxidation. This is inserted into the exit end of the pyrolysis tube in one manufacturer's configuration.

8. Preparation of Apparatus 8.1 Assemble apparatus in accordance with manufacturer's instructions. 8.2 Adjust the gas flows and the pyrolysis temperature to the desired operating conditions. The inlet temperature will depend upon which inlet method is used. See 4.2 and 4.9.

5. Reagents

5.1 Purity of Reagents--Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, 3 where such specifications are available. Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination. 5.2 Magnesium Perchlorate Mg(CIO4)2 for drying products of combustion (if permeation drier is not used.)

9. Calibration and Standardization 9.1 Prepare a series of calibration standards using a stock solution covering the range of operation and consisting of nitrogen type and matrix similar to samples to be analyzed. 9.2 Volumetric measurement of the injected sample can be obtained by filling the syringe to the 80 % level, retracting the plunger so that the lower liquid meniscus falls on the 10 % scale mark, and recording volume of liquid in the syringe. After the sample has been injected, again retract the plunger so that the lower liquid meniscus falls on the 10 % scale mark and record the volume of liquid in the syringe. The difference between the two volume readings is the volume of sample injected. 9.3 Alternatively, the sample injection device may be weighed before and after injection to determine the amount of sample injected. This test method provides greater precision than the volume delivery method, provided a balance with a precision of +0.01 mg is used. 9.4 Insert the syringe needle through the inlet septum up to the syringe barrel and inject the sample or standard at a uniform rate of 0.2 to 1,0 ~tL/s. Rate of injection is dependent on such factors as viscosity, hydrocarbon type and nitrogen concentration. Each user must adopt a method whereby a consistent and uniform injection rate is ensured.

NOTE 1: Warning--Strong oxidizer, irritant.

5.3 Inert Gas, argon or helium only, ultra-high purity grade (UHP). 5.4 Oxygen, ultra high purity (UHP). NOTE 2" Warning--Vigorously accelerates combustion.

5.5 Solvent--Toluene, isooctane, cetane, or other solvent similar to compound present in the sample to be analyzed. NOTE 3: Warning--Flammable solvents.

5.6 Nitrogen Stock Solution, 1000 gg N/mL.--Prepare a stock solution by accurately weighing I. 195 g of carbazole or 0.565 g of pyridine into a tared 100 mL volumetric flask. Acetone may be first used to dissolve carbazole. Dilute to volume with selected solvent. This stock may be further diluted to desired nitrogen concentrations. NOTE 4 - - P y d d i n e should be used with low boiling solvents (430"F). NOTE 5--Carbazole should be used with high boiling solvents. NOTE 6--Caution--Working standards should be remixed on a regular basis depending upon frequency of use and age. Typically, standards have a useful life of about 3 months.

NOTE 9 - - F o r the most consistent injection rate and best analytical results, a constant rate injection unit may be helpful. Consult manufacturer for recommendations.

5.7 Cupric Oxide Wire, as recommended by instrument manufacturer. 5.8 Quartz Wool. 5.9 Pyridine. NOTE 7: Warning--Flammable, irritant. 5.10 Carbazole.

NOTE 10--With direct injection below 5 mg/kg of nitrogen, the needle septum blank may becomeincreasinglyimportant. Error due to this can be avoidedby insertingthe syringeneedleinto the hot inlet and allowing the needle-septum blank to dissipate before injecting the sample. 9.5 For the method blank, rinse the syringe thoroughly with the solvent blank. Then inject the same amount of solvent blank as utilized with standards and obtain the reading. Measure the blank a second time and average the results. The solvent blank should contain less than 1 mg/kg of nitrogen. 9.6 If the system features a totalizer with calibration adjust, repeat the measurement of each calibration standard three times. The average of the three results shall be adjusted with the calibration setting to this average. System performance shall be checked with suitable calibration standard each day and when changing concentration ranges. 9.7 For those detectors not equipped with a calibration adjust, construct a standard curve as follows: Repeat the

5.11 Acetone. NOTE 8: Warning--Flammable.

6. Hazards 6.1 High temperature is employed in this test method. Extra care must be exercised when using flammable materials near the pyrolysis furnace. 3 Reagent Chemicals, American Chemical Society Specifications, American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed by the American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville, MD.

714

1~ D 4629 determination of each calibration standard and the blank three times to determine the average net response for each standard. Construct a curve plotting of milligrams of nitrogen injected versus detector response (integration count). The response curve should be linear and shall be checked at least once per week.

TABLE 1

Repeatability and

Reproducibility

Concentration (mg/kg n)

r

R

0.3 1 10 25 50 75 100

0.08 0.15 0.5 0.8 1.2 1.5 1.8

0.44 0.85 2.9 4.8 7.0 8.7 10.2

I0. Procedure I0.1 Sample sizes ranging from 3 to 40 ~tL are acceptable. It is advisable that the size of injected sample shall be similar to the size of injected standard. 10.2 Flush the microlitre syringe several times with the unknown sample. Determine the sample size as described in 10.3 and inject it at an even rate as described in 9.4. 10.3 Experience dictates the best sensitivity setting and sample size. Typical sample sizes have been used in the following ranges: Nitrogen, mg/kg 1 and less 10 100 >100 Dilute sample to most Convenient level.

S V I K

= = = =

slope of standard curve, mg N/count, volume of sample, I~L, detector response, intergration counts, and dilution factor (when applicable).

12. Precision and Bias 4

12.1 The precision of this test method as determined by statistical examination of interlaboratory results is as follows: 12.1.1 Repeatability--The difference between two test results obtained by the same operator with the same apparatus under constant operating conditions on identical test material would, in the long run, in the normal and correct operation of the test method, exceed the following values in only one case in twenty, where X = the average of the two test results. r 0.15(X) °'54

Sample Size, IsL up to 40 up to 8 up to 8

=

11. Calculation

12.1.2 Reproducibility--The difference between two single and independent results obtained by different operators working in different laboratories on identical test material would, in the long run, in the normal and correct operation of the test method, exceed the following values in only one case in twenty, where X = the average of the two test results. R = 0.85(X) °'~4

I 1.1 For analyzers equipped with a calibration adjust, calculate the nitrogen content of the sample parts per million (mg/kg) by mass as follows: Nitrogen, mg/kg = ( I - B) x K/(V x D) (l) Nitrogen, mg/kg = ( I - B) x K/M (2) where: D = density of sample, g/mL, K = dilution factor, V = volume of sample, ~tL, M = mass of sample, mg, I = visual display reading of sample, ng N, and B = average of visual display readings of blank, ng N. 11.2 For analyzers not equipped with calibration adjust, calculate the milligrams per kilograms by mass nitrogen as follows: Nitrogen, mg/kg = I x S x K/(V x D) (3)

12.2 The bias of this test method has not been determined. Subcommittee D.02.03.0C intends to determine bias for this test method when proper standards are available. 13. Keywords 13.1 catalyst poison; chemiluminescence; nitrogen content; oxidative combustion; petroleum hydrocarbons

where: D = density of sample, g/mL,

( Supporting data are available from ASTM Headquarters. Request RR:D021199.

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and ff not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend, ff you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 100 Barr Harbor Drive, West Conshohockan, PA 19428.

715

(~l~ Designation:D4735-96 Standard Test Method for Determination of Trace Thiophene in Refined Benzene by Gas Chromatography 1 Th~s standard is issued under the fixed designation D 4735; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (d indicates an editorial change since the last revision or reapproval.

OSHA Regulations, 29 CFR, paragraphs 1910.1000 and 1910.12005

1. Scope 1.1 This test method covers the determination of thiophene in refined benzene in the range from 0.5 mg/kg to 5.0 mg/kg. The range of the test method may be extended by modifying the sample injection volume, calibration range, or sample dilution with thiophene-free solvent. 1.2 This test method has been found applicable to benzene characteristic of the type described in Specifications D 2359 and D 4734 and may be applicable to other types or grades of benzene only after the user has demonstrated that the procedure can completely resolve thiophene from the other organic contaminants contained in the sample. 1.3 The following applies to all specified limits in this test method: for purposes of determining conformance with this test method, an observed value or a calculated value shall be rounded off "to the nearest unit" in the last right-hand digit used in expressing the specification limit in accordance with the rounding-off method of Practice E 29. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements, see Section 7.

3. Summary of Test Method 3.1 The thiophene concentration in refined benzene is determined at the milligram thiophene per kilogram sample level using conventional gas-liquid chromatography with a flame photometric detector. A reproducible volume of sample is injected. Quantitative results are obtained by the external standard technique using the measured peak area of thiophene. 4. Significance and Use 4.1 This test method is suitable for setting specifications on benzene and for use as an internal quality control tool where benzene is either produced or used in a manufacturing process. 4.2 This test method was found applicable for determining thiophene in refined benzene conforming to the specifications described in Specification D 2359 and may be applicable toward other grades of benzene if the user has taken the necessary precautions as described in the text. 4.3 This test method was developed as an alternative technique to Test Method D 1685. 5. Apparatus 5.1 Gas Chromatograph--Any chromatograph having a flame photometric detector may be used which can operate at the typical conditions described in Table 1. The user is referred to Practice E 260 for additional information about gas chromatography principles and procedures. 5.2 ColumnmThe column must provide complete resolution of thiophene from benzene and any other hydrocarbon impurities because of potential quenching effects by hydrocarbons on the light emissions from the thiophene. The columns described in Table 1 have been judged satisfactory. 5.3 Detector--Any flame photometric detector (FPD) can be used, provided it has sufficient sensitivity to produce a minimum peak height twice that of the base noise for a 4-~tL injection volume of 0.5 mg/kg thiophene in benzene. The user is referred to Practice E 840 for assistance in optimizing the operation and performance of the FPD. 5.4 Integrator--Electronic integration is recommended. 5.5 Recorder, a-c, l-mV range strip chart recorder is recommended. 5.6 Microsyringe, 10-I.tLcapacity.

2. Referenced Documents 2.1 A S T M Standards: D 1193 Specification for Reagent Water2 D 1685 Test Method for Traces of Thiophene in Benzene by Spectrophotometry3 D 2359 Specification for Refined Benzene-5353 D 3437 Practice for Sampling and Handling Liquid Cyclic Products 3 D 4734 Specification for Refined Benzene 5453 E 29 Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications 4 E 260 Practice for Packed Column Gas Chromatography4 E 840 Practice for Using Flame Photometric Detectors in Gas Chromatography4 2.2 Other Document: t This test method is under the jurisdiction of ASTM Committee D-16 on Aromatic Hydrocarbons and Related Chemicals and is the direct responsibility of Subcommittee DI6.0E on Instrumental Analysis. Current edition approved Feb. 10, 1996. Published April 1996. Originally published as D 4735 - 87. Last previous edition D 4735 - 87 (1991) ~'. 2 Annual Book of ASTM Standards, Vol 11.01. 3 Annual Book of ASTM Standards, Vol 06.04. 4 Annual Book of ASTM Standards, Vol 14.02.

5 Available from Superintendent of Documents, U.S. Government Printing Office, Washington, DC 20402.

716

~ TABLE 1 Column Tubing Phase Concentration, weight % Support Mesh Detector H=, mL/min Air I, mL/min Air II, mL/min Gas chromatographic conditions Inlet, *C Detector, °C Carrier Gas Flow Rate, mL/min Column Temperature, *C

D 4735

Thiophene in Benzene Instrumental Conditions A

B

C

6 ft x 1/8 in. Ni Steel TCEPE a 7 Chromosorb P-AW a 100/120

15 ft by 1/8 in. stainless steel SP-1000 10 Supelcoport 60/80

10 ft by 1/8 in. stainless steel OV-351 10 Chromosorb P-AW 80/100

140 80 170

140 80 170

140 80 170

150 220 helium 30 70

170 220 helium 30 90

180 250 helium 30 70

A Tetracyanoethylated pentaerythritol or pentrile. a Chromosorb P Is a registered trademark of the Manville Corp.

5.7 Volumetric Flasks, 50, 100 and 500-mL capacity. 5.8 Separatory Funnel, 1-L capacity.

6. Reagents and Materials

(CdCI2). Finally, wash with another lO0-mL portion of water and filter the benzene through medium filter paper into a storage bottle, stopper the bottle tightly and save for future use.

6.9 Sulfuric AcidmConcentrated H2SOa. 6.10 Thiophenes.

6. t Purity of Reagents--Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, where such specifications are available. 6 Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination. 6.2 Purity of Water--Unless otherwise indicated, reference to water shall be understood to mean reagent water conforming to Type IV of Specification D 1193. 6.3 Carrier Gas, nitrogen or helium, chromatographic grade. 6.4 Hydrogen, zero grade. 6.5 Compressed Air, hydrocarbon-free. 6.6 Cadmium Chloride Solution (20 g/L)--Dissolve 20 g of anhydrous cadmium chloride CdCI2 into 200 mL of water and dilute to 1 L. 6.7 Isatin Solution7--Add 0.5 g of isatin to 200 mL of chloroform. Heat under a fume hood to a temperature just below the boiling point of chloroform (61"C) and maintain for 5 min with stirring. Filter the hot solution through hardened rapid-filter paper into a 250-mL volumetric flask and dilute to volume. 6.8 Benzene, Thiophene-Free~Wash 700 mL of benzene in a 1000-mL separatory funnel to which has been added 5 mL of isatin solution, with successive 100-mL portions of concentrated sulfuric acid until the H 2 S O 4 layer is light yellow or colorless. Wash the benzene with 100 mL of water, then twice with 100 mL of cadmium chloride solution

7. Hazards 7.1 Benzene is considered a hazardous material. Consult current OSHA regulations and supplier's Material Safety Data Sheets, and local regulations for all materials used in this method. 8. Sampling and Handling 8.1 Sampling of benzene should follow safe rules in order to adhere to all safety precautions as outlined in the latest OSHA regulations. Refer to Practice D 3437 for proper sampling and handling of benzene. 9. Preparation of the Apparatus 9.1 The chromatographic separation of trace level sulfur compounds can be complicated by absorption of the sulfur compounds by the gas chromatographic system, Therefore, care should be taken to properly free the system of active sites where absorption or reactions could take place. 9.2 Follow the manufacturer's instructions for mounting the column into the gas chromatograph and adjusting the instrument to conditions described in Table 1. Allow the instrument and detector sufficient time to reach equilibrium. 10. Calibration Curve 10.1 Prepare a 500-mL stock solution of thiophene in benzene at the 100 mg/kg level by adding 0.04 g (38.0 gL) of thiopbene to 435 g (500 mL) of thiophene-free benzene. 10.2 Calculate the thiophene content of the stock solution according to the following equation: Thiophene, mg/kg = (.4 × 103)/B where:

6 Reagent Chemicals, American Chemical Society Specifications, American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed by the American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and Natwnal Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville, MD. 7 Isatin 2,3-indolinedione such as Aldrich Catalog No. 11,461-8, available from Aldrich Chemical Co., Inc., 940 W. Saint Paul Ave., Milwaukee, WI 53233, or equivalent has been found satisfactory for this purpose.

s Thiophene such as Aldrich Catalog No. T3,180-1, available from Aldrich Chemical Co., Inc., 940 W. Saint Paul Ave., Milwaukee, Wi 53233, or equivalent has been found satisfactory for this purpose.

717

~ ) D 4735 1.79

IHZOP~EIE $0.33

.... O0

I . . . . . . . . I.I )lo

I ' ' ' ' 1 ' ' ' ' 1 ' ' ' ' 1 ' ' ' ' 1 ' ' 1 ' 1 , ' ' ' 1 ' ' ' ' 4S LO 7,S 90 IO.g ILO $$S

t§.OI

N|NUT[S

FIG. 1

Chromatogram Illus~ating the Analysis of 1.10 mg/kg Thiophene in Benzene

A B

-- weight of thiopcnc, mg, and = weight of benzene, g. I0.3 Prepare five calibration blends ranging from 0.00 to 10.0 mg/kg of thiophene in benzene by diluting the appropriate volume of stock solution into a known volume of thiophcnc-frcc benzene. I0.4 For example, an 87.0 mg/kg stock solution was prepared by dissolving 0.0378 g thiophcnc into 435 g of benzene. Aliquots of 0.00, 0.75, 1.0,2.0, and 5.0 m L of stock solution wcrc dissolved in 100 m L ofthiophcnc-frcc benzene to produce 0.00, 0.65, 0.87, 1.75, and 4.35 mg/kg, respectively. 10.5 Inject 4.0 ~L of each solution into the chromatograph. Integrate the area under the thiophene peak. Each standard solution and the blank should be analyzed in triplicate. NOTE l--Injection volumesmust be consistentand reproducible. 10.6 Prepare a calibration curve by plotting the intcgratod peak area versus milligram per kilogram of thiophen¢ on a sheet of log/log graph paper. NOTE 2 - - I n the sulfur mode, the FPD will exhibit a response that is

a nonlinear power law function. Please refer to Practice E 840 for additional informationon the characteristicsand usageof the FPD. 11. Procedure 11.1 Charge 4.0 ~tL of sample into the chromatograph. 11.2 Measure the area of the thiophene peak. The measurement of the sample peak should be consistent with the method for measuring peak areas in the calibration blends. A typical chromatogram is shown in Fig. 1 representing 1.10 mg/kg thiophene in benzene.

the calibration curve prepared in 10.6. 13. Report 13.1 Report the thiophene concentration to the nearest 0.01 mg/kg. 14. Precision and Bias 14.1 Precision: 14. I. 1 The following criteria should bc used to judge the acceptability of the 95 % probability level of the results obtained by this test method. The criteria were derived from a round robin between five laboratories. The data were obtained over 2 days using different operators. 14.1.2 Intermediate Precision (formerly called Repeatability)mResults in the same laboratory should not be considered suspect unless they differ by more than the amount shown in Table 2. 14.1.3 ReproducibilitynThe results submitted by two TABLE 2 Thiophene Concentration,

Intermediate Precision and Reproducibility Repeatability,

Reproducibility,

mg/kg

mg/kg

rng/kg

0.8O

0.040 0.078

0.060

1.80

0.078

laboratories should not be considered suspect unless they differ by more than the amount shown in Table 2. 14.2 Bias--The bias in this test method is being determined.

15. Keywords 15.1 benzene; flame photometric detector; gas chromatography; thiophene

12. Calculation 12.1 Determine the amount of thiophene directly from

718

tJ~ D 4735 The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned/n this standard. Users of this standard are expressly advised that detarm/nation of the validity of any such patent rights, and the risk of infringement of such rights, are entire/}/their own responsibility. This standard Is subject to revision at any time by the responsible technical committee and must be reviewed every five years and ff not revised, either reepproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend, ff you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 100 Barr Harbor Drive, West Conshohockan, PA 19428.

719

Designation: D 4737 - 96a

IP@ :,',",.:':,::,','::~,

An American National Standard

Designation: 3 8 0 / 9 4

Standard Test Method for Calculated Cetane Index by Four Variable Equation 1 This standard is issued under the fixed designation D 4737; the number immediately following the designation indicates the year of original adoption or, in the ease of revision, the year of last revision. A number in parentheses indicates the year of last reapprnval. A superscript epsilon (0 indicates an editorial change since the last revision or reapproval.

1. Scope 1.1 The calculated Cetane Index by Four Variable Equation provides a means for estimating the ASTM eetane number of distillate fuels from density and recovery temperature measurements. The value computed from the equation is termed the Calculated Cetane Index by Four Variable Equation. 2 1.2 The Calculated Cetane Index by Four Variable Equation is not an optional method for expressing ASTM octane number. It is a supplementary tool for estimating cetane number when used with due regard for its limitations. 1.3 The test method "Calculated Cetane Index by Four Variable Equation" is particularly applicable to Grade I-D and Grade 2-D diesel fuel oils containing straight-run and cracked stocks, and blends of the two. It can also be used for heavier fuels with 90 % recovery points less than 382"C and for fuels containing non-petroleum derivatives from tar sands and oil shale. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

the ASTM cetane number and the density and 10 %, 50 %, and 90 % recovery temperatures of the fuel. The relationship is given by the following equation: CCI = 45.2 + (0.0892)(Tlojv) + [0.131 + (0.901) (B)][TsoN] + [0.0523 - (0.420)(B)] [TgoN] + [0.00049][(Tie,v)2 -- (Tgo~v)2] + (107)(B) + (60)(B)2 where: CCI = Calculated Cetane Index by Four Variable Equation, D = Density at 15"C, determined by Test Method D 1298, DN = D - 0 . 8 5 , B

= [e (-3"s×DN)] -

I,

T~o -

2. Referenced Documents

2.1 ASTM Standards: D 86 Test Method for Distillation of Petroleum Products 3 D 613 Test Method for Cetane Number of Diesel Fuel OiP D 1298 Test Method for Density, Relative Density (Specific Gravity), or API Gravity of Crude Petroleum and Liquid Petroleum Products by Hydrometer Method 3 D 4052 Test Method for Density and Relative Density of Liquids by Digital Density Meter5 3. Summary of Test Method 3.1 A correlation in SI units has been established between This test method is under the jurisdiction of ASTM Committee 1)-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee DOZE on Burner, Diesel, and Gas Turbine Fuel Oils. Current edition approved Nov. 10, 1996. Published January 1997. Originally published as D 4737 - 87. Last previous edition D 4737 - 96. 2 This method of estimating eetane number was developed by Chevron Research Co. See Ingham, M. C., et al. "Improved Predictive Equations for Cetane Number," SAE Paper No 860250. 3 Annual Book of A S T M Standards, Vol 05.01. 4 Annual Book of A S T M Standards, Vol 05.04. s Annual Book of A S T M Standards, Vol 05.02.

10% recovery temperature, *C, determined by Test Method D 86 and corrected to standard barometric pressure, TioN -- Tio - 215, Tso -- 50 % recovery temperature, *C, determined by Test Method 86 and corrected to standard barometric pressure, Tso~, = Tso - 260, T9o = 90 % recovery temperature, *C, determined by Test Method D 86 and corrected to standard barometric pressure, Tgo N = Tgo - 310. 3.2 The empirical equation for the Calculated Cetane Index by Four Variable Equation was derived using a generalized least squares fitting technique which accounted for measurement errors in the independent variables (fuel properties) as well as in the dependent variable (cetane number by Test Method D 613). The data base consisted of 1229 fuels including; commercial diesel fuels, refinery blending components and non-petroleum fuels derived from tar sands, shale, and coal. The analysis also accounted for bias amongst the individual sets of data comprising the data base.

4. Significance and Use 4.1 The Calculated Cetane Index by Four Variable Equation is useful for estimating ASTM cetane number when a test engine is not available for determining this property directly. It may be conveniently employed for estimating cetane number when the quantity of sample available is too small for an engine rating. In cases where the ASTM cetane number 720

~

D 4737

recommended range of application.

Part 1 - E s t i m a t e B a s e d on D e n s i t y a n d D 86 5 0 % R e c o v e r y T e m p e r a t u r e

5. Procedure

:: ,++:::

85 -D=0.685kg/L

.

-

~

75 :Part ! EsUmate:34. O,

:: .........

85

....

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: _~.

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5.1 Determine the density of the fuel at 15°C to the nearest 0.0001 kg/L, as described in Test Method D 1298 or Test Method D 4052. 5.2 Determine the l0 %, 50 %, and 90 % recovery temperatures of the fuel to the nearest l°C, as described in Test Method D 86.

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6. C a l c u l a t i o n or Interpretation o f R e s u l t s

I-'-

6.1 Compute the Calculated Cctane Index by Four Variable Equation using the equation given in 3. I. The calculation is more easily performed using a computer or programmablc hand calculator. Round the value obtained to the nearest one-tenth. 6. I. 1 Calculated Cetanc Index by Four Variable Equation can also be easily determined by means of the homographs appearing in Figs. 1 through 3. Figure l is used to estimate the cetanc number of a fuel based on its density at 15°C and its 50 % recovery temperature. Fig. 2 is used to determine a correction for the estimate from Fig. 1 to account for deviations in the density and the 90 % recovery temperature of the fuel from average values. Figure 3 is used to determine a second correction for the estimate from Fig. 1 to account for deviations in the l0 % and the 90 % recovery temperatures of the fuel from average values. The corrections determined from Figs. 2 and 3 arc summed algebraically with the cctanc number estimate from Fig. l to find the Calculated Cetanc Index by Four Variable Equation. The

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275

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300

325

ASTM D 86 50% Recovery Temperature, °C FIG. 1

Calculated

Index

Cetane

Part 2 - C o r r e c t i o n f o r D e v i a t i o n s in Dessity a n d D 86 9 0 % R e c o v e r y T e m p e r a t u r e f r o m A v e r a g e Values 5

o : 0.6as kg/C

4

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Part 3 - C o r r e c t i o n for D e v i a t i o n s in D 86 1 0 % a n d 90% Recovery Temperatures from Average Values

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ASTM O 86 90% Recovery Temperature,'oc

FIG. 2

-

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350

--r~_+ =20

Calculated Cetane Index

4/

of a fuel has been previously established,the Calculated Cetane Index by Four Variable Equation is useful as a cctane number check on subsequent samples of that fuel, provided the fuel's source and mode of manufacture remain unchanged. 4.2 Within the range from 32.5 to 56.5 cctane number, the expected error of prediction of the Calculated Cetanc Index by Four Variable Equation will bc less than __.2cetane numbers for 65 % of the distillatefuels evaluated. Errors may be greater for fuels whose properties fall outside the

721

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ASTM D 86 90% Recovery Temperature, °C FIG. 3

i

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~ O4737 method of using these nomographs is indicated by the illustrative example shown below and on Figs. 1 through 3.

7.

Measured Fuel Properties Test Method D 613 Cetane Number Test Method D 1298 Density at 15"C, kg/L Test Method D 86 10 % Recovery Temperature, *C Test Method D 86 50 % Recovery Temperature, °C Test Method D 86 90 % Recovery Temperature, "C

37.0 0.885 234 274 323

Calculated Cetane Index Estimate from Fig. 1 Correction from Fig. 2 Correction from Fig. 3

34.0 +0.6 +2.5 CCI s 37.1

6.2 The Calculated Cetane Index by Four Variable Equation possesses certain inherent limitations which must be recognized in its application. These are as follows: 6.2.1 It is not applicable to fuels containing additives for raising the cetane number. 6.2.2 It is not applicable to pure hydrocarbons, nor to non-petroleum fuels derived from coal. 6.2.3 Substantial inaccuracies in correlation may occur if the equation is applied to residual fuels or crude oils.

Precision and Bias

7.1 The determination of Calculated Cetane Index by Four Variable Equation from measured density at 15"C and measured 10 %, 50 % and 90 % recovery temperatures is exact. 7.2 Precision--The precision of the Calculated Cetane Index by Four Variable Equation is dependent on the precision of the original density and recovery temperature determinations which enter into the calculation. Test Method D 1298 has a stated repeatability limit of 0.0006 kg/L and a stated reproducibility limit of 0.0015 kg/L at 15°C. Test Method D 86 has stated repeatability and reprodueibility limits which vary with the rate of change of recovery temperature. See Figs. 2 through 7 and Tables 7 through 10 of Test Method D 86 for details. 7.3 Bias--No general statement is made on bias of this test method since a comparison with accepted reference values is not available. 8. Keywords 8.1 cetane; cetane index; diesel fuel

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of Infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 100 Bert Harbor Drive, West Conshohocken, PA 19428.

722

~[~

Designation: D 4808 - 92

An Arnencan NatK3nat Standard

Standard Test Methods for Hydrogen Content of Light Distillates, Middle Distillates, Gas Oils, and Residua by Low-Resolution Nuclear Magnetic Resonance Spectroscopy 1 This standard is issued under the fixed designation D 4808; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (~) indicates an editorial change since the last revision or reapproval.

1. Scope 1.1 These test methods cover the determination of the hydrogen content of petroleum products ranging from atmospheric distillates to vacuum residua using a continuous wave, low-resolution nuclear magnetic resonance spectrometer. (Test Method D 3701 is the preferred method for determining the hydrogen content of aviation turbine fuels using nuclear magnetic resonance spectroscopy.) 1.2 Three test methods are included here that account for the special characteristics of different petroleum products and apply to the following distillation ranges: Test Method

Petroleum Products

Boiling Range, "C ('F) (approximate)

A B

Light Distillates Middle Distillates, Gas Oils Residua

15-260 (60-500) 200-370 (400-700) 370-510 (700-950) 510+ (950+)

C

1.3 The preferred units are mass percent. 1.4 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements, see Section 6.1.

records in a non-destructive fashion the absolute concentration of hydrogen atoms in the reference standard and test sample. The absolute hydrogen concentrations reported by the integrator on the NMR instrument for the standard and test specimens are used as a means of comparing the theoretical hydrogen content of the standard with that of the sample, the result being expressed as the hydrogen content (on a mass percent basis) of the sample. 3.2 In order to assure an accurate measure of the absolute hydrogen content of the reference standard and sample, it is necessary to ensure that the measured hydrogen integrator counts are always directly proportional to the absolute hydrogen content of the standard and sample. 3.3 Undercounting of the reference standard with respect to the sample is avoided in Test Methods B and C by dilution of the standard with a relaxation reagent solution. Undercounting of highly viscous or solid test samples is avoided by dissolving the sample in a non-hydrogen containing solvent, which assures that all of the weighed sample is in a fluid and homogeneous solution at the time of measurement. An elevated sample temperature at the time of measurement also ensures a homogeneous liquid-phase sample.

4. Significance and Use

2. Referenced Documents

4.1 The hydrogen content represents a fundamental quality of a petroleum product that has been correlated with many of the performance characteristics of that product. 4.2 This test method provides a simple and more precise alternative to existing test methods, specifically combustion techniques, (Test Method D 5291), for determining the hydrogen content on a range of petroleum products.

2.1 ASTM Standards: D3701 Test Method for Hydrogen Content of Aviation Turbine Fuels by Low Resolution Nuclear Magnetic Resonance Spectrometry2 D4057 Practice for Manual Sampling of Petroleum and Petroleum Products2 D 5291 Test Method for Instrumental Determination of Carbon, Hydrogen, and Nitrogen in Petroleum Products and Lubricants3

5. Apparatus NOTEl--This test method has been written around the Newport Analyzer Mark IIIF or it's replacement version, the Newport 4000 (Oxford AnalyticalInstruments,Ltd., Oxford, England)and the details ofthe test methodare to be read in conjunctionwith the manufacturer's handbook. These instruments have demonstrated statisticallyindistinguishable performance in these standard methods and in Test Method D 3701. Any similarinstrumentis acceptable providedthat the new instrument is adequatelycorrelatedand proved to be statisticallysimilar.

3. Summary of Test Methods 3.1 A test specimen is compared in a continuous wave, low-resolution nuclear magnetic resonance (NMR) spectrometer with a reference standard sample. The spectrometer

5.1 Nuclear Magnetic Resonance Spectrometer: 5.1.1 A low.resolution, continuous wave instrument capable of measuring a nuclear magnetic resonance signal due to hydrogen atoms in the sample and includes an excitation and detection coil of suitable dimensions to contain the test cell; an electronic unit, to control and monitor the magnet

t This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee I:)02.03 on Elemental Analysis. Current edition approved Aug. 15, 1992. Published October 1992. Originally published as D 4808 - 88. Last previous edition D 4808 - 88. 2 Annual Book of ASTM Standards, Vol 05.02. 3 Annual Book of ASTM Standards, Vol 05.03.

723

(~ 8 HOLES lOS DEEP FOR NESSLER TUBES

D 4808 6. Reagents and Materials 4

:~ HOLES I05 DEEP

6.1 Purity of Reagents--Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, where such specifications are available. 4 Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination. 6.2 ReJbrence Standard--n-Dodecane.

203

~

PLASTIC 'KNOD

k.Jk.Jk.Jk.J

NOTE 2: Warning--Flammable. 4l

METAL INSERTION RO~,~ APPROX S 0

6.3 Relaxation Reagent Solution prepared from ferric acetylacetonate (Fe(acac)3 - MW = 353.16, reagent grade)-Prepare a fresh 0.02 M Fe(acac)3 solution by dissolving 1.77 g of Fe(acac)3 in 250 mL TCE. If any of the ferric acetylacetonate remains undissolved, filter the solution and use the filtrate in subsequent steps. 6.4 "l'etrachh,'oethylene (7'CE).

!

3S 0

I- _t.S~.

t ii ii i I iI ~

:

I t I __.j

N(n[~ 3: Warning--Cancer-suspect agent.

[ 1 ~ RREAD

1

CONDITIONING BLOCK MATERIAL ALUMINIUM ALLOY

"F

7. Sampling

7.1 Take a homogeneous sample in accordance with Practice D 4057. Mix the sample prior to taking a representative aliquot as the test specimen. Middle distillates, gas oils and residue can require heating to facilitate mixing to obtain a homogeneous test specimen as described in 9.2.2.2 and 9.3.2.

_.,J

Pt.UG MATERIAL PTFE

FIG. 1 ConditioningBlock and InsertionRod 8. Preparation of Apparatus

and coil, and containing: circuits, to control and adjust the radio-frequency level and audio-frequency gain; and integrating counter, with variable time period in seconds. 5.1.2 Test Methods B and C also require that the instrument has the ability to equilibrate samples within the probe at an elevated temperature (50°C). 5.2 Conditioning Block--A block of aluminum alloy drilled with holes of sufficient size to accommodate the test cells with the mean height of the sample being at least 20 mm below the top of the conditioning block, capable of holding the sample at the given test temperature (see Fig. 1). 5.3 Test Cells--Nessler-type tubes of approximately 100mL capacity with an external diameter of 33.7 4- 0.5 mm and an internal diameter of 31.0 4- 0.5 mm marked at a distance of 51 mm above the bottom of the tube by a ring around the circumference. 5.4 Pol.vtetrafluoroethylene (PTFE) Plugs for closing the test cells and made from pure PTFE. 5.5 Insertion Rod--A metal rod with a threaded end used for inserting and removing the PTFE plugs from the test cells (see Fig. 1). 5.6 Analytical Balance--A top pan-type balance, capable of weighing the test cells in an upright position to an accuracy of at least 0.001 g. 5.7 Beakers, 150 mL and 50 mL with pour spouts. 5.8 Glass Stirring Rod, approximately 250-mm length.

8.1 Read and follow the manufacturer's instructions for preparing the instrument to take measurements. Take special care to prevent the instrument and conditioning block from experiencing rapid temperature fluctuations; for example, avoid direct sunlight and drafts resulting from air conditioning or fans. 8.2 Adequate temperature equilibration of the instrument probe assembly after adjustment to an elevated temperature is essential. Due to the size of test specimen and probe assembly specified by these methods, adequate thermal equilibration may require several hours. 8.3 The results obtained during the use of the instrument are susceptible to error arising from changes in the local magnetic environment. Exercise care to ensure that there is a minimum of metallic material in the immediate vicinity of the instrument and keep this constant throughout the course of a series of determinations. 8.4 Set the instrument controls to the following conditions: 4"Reagent Chemicals, American Chemical Society Specifications," Am. Chemical Soc., Washington, DC. For suggestions on the testing of reagents not listed by the American Chemical Society, see "Reagent Chemicals and Standards," by Joseph Rosin, D. Van Nostrand Co., Inc., New York, NY, and the "United States Pharmacopeia."

724

D 4808 Parameter Gate width (G) Audio-Frequency Gain (Arb. units) Radio-frequency Excitation (taA) Integration Time (seconds) Probe Temperature ('C)

Test Method A

Test Method B

Test Method C

1.5 500

1.5 400-600

1.5 400-600

20 128 Room Temp

20 128 50

20 128 50

NOTE 2--Burets can also be used to aid the addition of TCE and relaxation reagent solutions. 9.2.1.4 Transfer this solution from the beaker to the test cell using the glass rod to prevent splashing the liquid above the line inscribed on the test cell. Fill the test cell to the prescribed level, just below this mark. 9.2.1.5 Continue as in 9.1.2 through 9.1.3. 9.2.1.6 Weigh the test cell containing the reference solution and plug. Record the weight of the reference solution to the nearest 0.001 g as W~. 9.2.1.7 Weigh the beaker and glass rod containing the unused solution and record the weight of the remaining solution to the nearest 0.001 g as W2. 9.2.1.8 Place the test cell containing reference solution into the conditioning block to equilibrate. 9.2.2 Test Specimen Preparation: 9.2.2. l Take a clean and dry test cell with PTFE plug and a 150-mL beaker with glass stirring rod. Weigh the test cell with plug and the beaker with glass rod to the nearest mg and record as tare weights. 9.2.2.2 Add 20 g of the test specimen to the beaker. Record this weight to the nearest 0.001 g as S,... All samples must be homogeneous prior to sampling. If the sample is viscous or contains waxy materials, heat the sample in its container to approximately 60"C and mix with a high-speed shear mixer prior to sampling. 9.2.2.3 To the beaker containing sample, add 13.3 g of TCE (40 % dilution of the test sample with TCE). Mix the solution thoroughly using the glass rod. NOTE 4--For some samples, it is necessaryto heat and stir until the sample is completely homogeneous. Maintain the liquid level with additional TCE during heating if necessary. 9.2.2.4 Continue as in 9.2.1.4 through 9.2.1.8. 9.3 Test Method CmResidue 9.3.1 Take a clean and dry test cell with PTFE plug, a 150-mL beaker, and a glass rod. Weigh each of them to the nearest 0.001 g and record as tare weights. 9.3.2 Add 15 g of reference standard or test specimen to the beaker. Record this weight to the nearest 0.001 g as Sw. All samples must be homogeneous prior to sampling. If the sample is viscous or contains waxy materials, heat the sample in its container to approximately 60"C and mix with a high-speed shear mixer prior to sampling. 9.3.3 To the beaker, add 17.2 g of TCE and 5.3 g of relaxation reagent solution (60 % dilution with 1 mg of relaxation reagent per 1 mL). Mix thoroughly using the glass stirring rod. (See Note 4.) 9.3.4 Continue as described in 9.2.1.4 through 9.2.1.8.

8.5 Place a test cell containing typical test specimen in the coil and assure that the tuning of the instrument results in two coincident resonance curves on the oscilloscope. Recheck this condition after changing samples. 8.6 Remove the test cell from the coil and observe that the signal readout from the instrument integrator is now 0 _ 3 units. Check this condition periodically to ensure that no contamination of the coil with hydrogen-containing material has occurred. 9. Preparation of Test Specimen and Standard 9.1 Test Method A--Light Distillates 9.1.1 Take a clean and dry test cell and PTFE plug and weigh them together to the nearest 0.001 g and record the weight. Add 30 _+ 1 mL of the reference standard or test specimen to the tube, taking extreme care to prevent splashing the liquid above the line inscribed on the tube. Use a pipet for this operation. 9.1.2 Using the insertion rod, push the PTFE plug into the tube until it is about 3 cm above the liquid surface, being careful to keep the tube upright. A gentle twisting or rocking of the plug as it is inserted usually aids the escape of air from the test cell and ensure that the lip of the PTFE plug is turned up around the entire circumference. Take care to assure that this is so, since a plug that is not properly inserted allows sample evaporation and gives rise to erroneous results. NOTE l--If difficultiesare encountered in the insertion of the PTFE plug, this operation is facilitatedby insertinga length of thin (less than 0.2-ram diameter) and clean copper wire down the inside surface of the test cell until it is approximately4 cm from the graduation mark and then pushingthe PTFE plug down past the wire which is then removed. 9.1.3 Unscrew the insertion rod carefully and remove without disturbing the plug and without contacting the liquid with the under surface of the plug. 9.1.4 Weigh the test cell containing the test specimen or standard and plug. Record this weight as Ws or WR, respectively, to the nearest 0.001 g. 9.1.5 Place the test cell in the sample conditioning block to equilibrate. 9.1.6 Use procedures 9.1.1 to 9.1.5 to prepare both the reference and sample test cells. 9.2 Test Method B--Middle Distillates, Gas Oils 9.2.1 Reference Standard Preparation: 9.2.1.1 Take a clean and dry test cell with PTFE plug and a 150-mL beaker with glass rod. Weigh the test cell with plug and beaker with glass rod to the nearest 0.001 g and record as tare weights. 9.2.1.2 Add 20 g of the reference standard, n-dodecane, to the beaker. Record this weight to the nearest 0.001 g as Sw. 9.2.1.3 To the beaker add 8.6 g TCE and 4.7 g of relaxation reagent solution as described in section 6.3 consisting of TCE and Fe(acac) 3 (40 % dilution of reference standard with I mg relaxation reagent/mL). Mix thoroughly using the glass stirring rod.

10. Procedures 10.1 Test Methods A, B, and C: 10.1.1 Leave the reference standard and the test specimens in the conditioning block for at least 0.5 h, to ensure that they reach the specified test temperature. The temperature of the conditioning block must be maintained at the same temperature required for the NMR measurement as specified in 8.4. 10.1.2 Take the reference standard and place it carefully into the instrument sample probe (coil), being careful that the liquid does not splash onto the under side of the PTFE plug. When fully inserted, the top of the test cell is just above 725

~) D 4808 Repeatability (r) end Reproducibility (R) Precision Intervals for Test Methods A, B, and C in Units of Mass Percent Hydrogen

of material during the transfer to the test cell. 1 !. i. 1 Test Method A - - N o t applicable. 11. !.2 Test Methods B and C:

TABLE 1

mess ~

Test Method A

Test Method B

Test Method C

H

r

R

r

R

r

R

9.00 9.25 9.50 9.75 10.00 10,25 10.50 10.75 11.00 11.25 11.50 11.75 12.00 12.25 12.50 12.75 13.00 13.25 13.50 13.75 14.00 14.25 14.50 14.75 15.00 15.25 15.50 15.75 16,00

0.13 0.13 0.13 0.12 0.12 0.12 0.12 0.12 0.12 0.12 0.12 0.12 0.12 0.12 0.12 0.12 0.12 0.12 0.11 0.11 0.11 0.11 0.11 0.11 0.11 0.11 0.11 0.11 0.11

0.42 0.41 0.41 0.41 0.40 0.40 0.40 0.40 0.40 0.39 0.39 0.39 0.39 0.38 0.38 0.38 0.38 0.38 0.38 0.37 0.37 0.37 0.37 0,37 0.37 0.36 0,36 0.36 0.36

0.12 0.13 0.14 0.14 0.15 0.16 0.17 0.17 0.18 0.19 0.20 0.21 0.22 0.23 0.23 0.24 0.25 0.26 0.27 0.28 0.29 0.30 0.32 0.33 0.34 0.35 0.36 0.37 0.38

0.25 0.27 0.28 0.29 0.31 0.33 0.34 0.36 0.38 0.39 0.41 0.43 0.45 0.47 0.48 0.50 0.52 0.54 0.56 0.59 0.61 0.63 0.65 0.67 0.70 0.72 0.74 0.77 0.79

0.41 0.39 0.37 0.35 0.33 0.32 0.30 0.29 0.28 0.26 0.25 0.24 0.23 0.22 0.21 0.20 0.20 0.19 0.18 0.18 0.17 0.16 0.16 0.15 0.15 0.14 0.14 0.13 0.13

0.87 0.82 0.78 0.74 0.70 0.67 0.64 0.61 0.58 0.56 0.53 0.51 0.49 0.47 0.45 0.43 0.42 0.40 0.39 0.37 0.36 0.35 0.33 0.32 0.31 0.30 0.29 0.28 0,27

WR or Ws = Sw × ( Wi)/( W, + W,) where: WR or W s = weight of reference material or test specimen in the test cell, Sw = weight of standard or test specimen in the preparation beaker, W~ = weight of solution in the NMR test cell, W2 = weight of solution remaining in the preparation beaker. 11.2 Hydrogen Content: 11.2.1 Calculate mass percent hydrogen content as follows: Hydrogen Content (mass %) (S/R) × (WR/Ws) × (15.39) where: S = mean of integrator counts on test specimen under test, R --- mean of integrator counts on reference standard, WR -- mass of reference standard in the test cell, Ws ffi mass of test specimen in the test cell and, 15.39 = mass % hydrogen in the reference sample, ndodecane.

12. Report 12.1 Report the mass percent hydrogen content on the test sample to the nearest 0.01 mass % hydrogen.

the cover of the instrument unit. 10.1.3 Check that the peaks on the oscilloscope are coincident and, if this is not so, adjust the tuning as described by the manufacturer's instructions until they are. 10.1.4 After the reference standard is in the magnet unit for at least 3 s, push the reset button to begin a measurement. 10.1.5 After a count time of 128 s, the digital display stops at its final value. Record the integrator counts and reset the instrument to take a second measurement. Record a total of seven readings, averaging the last five. 10.1.6 Remove the test cell containing reference standard from the instrument and reweigh after it has cooled to room temperature. If this weight differs significantly from the weight obtained in 9.1.4 or 9.2.1.6, the PTFE plug need not have sealed properly and the result is considered suspect. This additional weighing step is required due to the presence of the TCE diluent in some samples. 10.1.7 Replace the reference standard in the conditioning block and make similar readings on the test specimen to be tested.

13. Precision and Bias s 13.1 The precision of this test method as obtained by statistical examination of interlaboratory test results is as follows: 13.1.1 Repeatability--The difference between successive test results obtained by the same operator with the same apparatus under constant operating conditions on identical test material would, in the long run, in the normal and correct operation of the test method exceed the following value only in one case in twenty (see Table 1): Test Method A--Light Distillates Test Method B--Middle Distillates and Gas Oils Test Method C--Residua

0.22(X o 2s) 0.0015(X 2) 33.3(X-2)

where X is the sample mean. 13.1.2 Reproducibility--The difference between two single and independent results obtained by different operators working in different laboratories on identical test material would, in the long run, in the normal and correct operation of the test method exceed the following value in one case in twenty (see Table 1):

NOTE 5 - - M e a s u r e m e n t s are affected by temperature variations in the sample and reference standard so these test cells are always returned to the conditioning block if additional measurements are anticipated on the same sample.

Test Method A--Light Distillates Test Method B--Middle Distillates and Gas Oils Test Method C--Residua

0,72(X o 25) O.0031(X2) 70.3(X -2)

where X is the sample mean.

11. Calculation 11.1 Determination of the weight of test specimen or reference material delivered to the NMR test cell. This calculation accounts for the dilution with TCE and the loss

s Supporting data are available from ASTM Headquarters. Request RR:D021186.

726

1~) D 4808 13.2 Bias: 13.2. l A 1985 research report indicated that the hydrogen content determined by Test Methods A, B, and C are not biased with respect to data obtained by combustion techniques. 13.2.2 A 1977 research report indicated that the hydrogen content determined by Test Method A (same as D 3701) is

biased high with respect to the expected value for pure known hydrocarbons. 14. Keywords 14.1 distillate; gas oil; hydrogen content; light distillate; middle distillate; nuclear magnetic; petroleum products; residua; resonance spectroscopy

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted m connection with any item mentioned in this standard, Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsJbihty. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every hve years and if not revised, either reepproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend, ff you feel that your comments have not received s fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103.

727

~{~l~) Designation:D 4810-88 (Reapproved 1994)~1 Standard Test Method for Hydrogen Sulfide in Natural Gas Using Length-of-Stain Detector Tubes 1 This standard is issued under the fixed designation D 4810; the number immediately following the designation indicates the year of

original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last re.approval. A superscript epsilon (~) indicates an editorial change since the last revision or reapproval. el Section 8 was added editorially in January 1994.

1. Scope 1.1 This test method covers a procedure for a rapid and simple field determination of hydrogen sulfide in natural gas pipelines. Available detector tubes provide a total measuring range of0.5 ppm by volume up to 40 % by volume, although the majority of applications will be on the lower end of this range (that is, under 120 ppm). 1.2 Typically, sulfur dioxide and mercaptans may cause positive interferences. In some cases, nitrogen dioxide can cause a negative interference. Most detector tubes will have a "preclcanse" layer designed to remove certain interferences up to some maximum interferent level. Consult manufacturers' instructions for specific interference information. 1.3 The values stated in SI units are to be regarded as the standard. 1.4 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

system is direct reading, easily portable, and completely suited to making rapid spot checks for hydrogen sulfide under field conditions. 4, Significance and Use

4.1 The measurement of hydrogen sulfide in natural gas is important, due to the gas quality specifications, the corrosive nature of H2S on pipeline materials, and the effects of H2S on utilization equipment. 4.2 This test method provides inexpensive field screening of hydrogen sulfide. The system design is such that it may be used by nontechnical personnel, with a minimum of proper training. 5. Apparatus 5.1 Length-of-Stain Detector Tube and Calibration Scale--A sealed glass tube with breakoff tips sized to fit the tube holder of the pump. The reagent layer inside the tube, typically a silica gel s u b s ~ t e coated with the active chemicals, must be specific for hydrogen sulfide, and must produce a distinct color change when exposed to a sample of gas containing hydrogen sulfide. Any substances known to interfere must be listed in the instructions accompanying the tubes. A calibration scale should be marked directly on the tube, or other markings which provide for easy interpretation of hydrogen sulfide content from a separate calibration scale supplied with the tubes. The calibration scale shall correlate hydrogen sulfide concentration to the length of the color stain. Shelf life of the detector tubes must be a minimum of two years from date of manufacture, when stored according to manufacturers' recommendations. 5.2 Detector Tube Pump---A hand-operated pump of a piston or bellows type. It must be capable of drawing 100 cm 3 per stroke of sample through the detector tube with a volume tolerance of:t:5 cm3. 3 It must be specifically designed for use with detector tubes.

2. Referenced Document 2.1 Gas Processors Association Standard: No. 2377-86 Test for Hydrogen Sulfide in Natural Gas Using Length of Stain Tubes 2 3. Summary of Test Method

3.1 The sample is drawn through a detector tube fdled with a specially prepared chemical. Any hydrogen sulfide present in the sampling reacts with the chemical to produce a color change, or stain. The length of the stain produced in the detector tube, when exposed to a measured volume of sample, is directly proportional to the amount of hydrogen sulfide present in the sample. A hand-operated piston or bellows-type pump is used to draw a measured volume of sample through the tube at a controlled rate of flow. The length of stain produced is converted to ppm (by volume) hydrogen sulfide (H2S), by comparison to a calibration scale supplied by the manufacturer for each box of detection tubes (higher range tubes have units of percent by volume). The

NOT~ I~A detector tube and pump together form a unit and must be used as such. Each manufacturer calibrates detector tubes to match the flowcharacteristicsof their specificpump. Crossingbrands of pumps and tubes is not permitted, as considerable loss of system accuracy is likelyto occur? (It should be noted that at leastone manufacturerallows extended samples up to 100 pumpstrokes to obtain lower detection levels. This may be automated for screening purposes by drawing the sample from an inert collapsable container by vacuum displacement.

i This test method is under the jurisdiction of ASTM Committee I).3 on Gaseous Fuels and is the direct responsibility of Subcommittee D03.05 on Determination of Special Constituents of Gaseous Fuels. Current edition approved April 29, 1988. Published June 1988. 2 Available from Gas Processors Association, 1812 First National Bank Bldg., Tulsa, OK 74103.

s Direct Reading Colorimetric Indicator Tubes Manual, 1st Ed., American Industrial Hygiene Association, 1976, Akron, OH 4431 !,

728

~)

D 4810

The sample flow rate should be maintained within ±5 % of the manufacturer's specified flow rate. Accuracy losses are apt to occur in such special applications, and such a system is recommended only for screening purposes. Consult manufacturers regarding limitations.)

CONTNOL VALVE\ SOURCEVALVE~

5.3 Gas Sampling Chamber--Any container that provides for access of the detector tube into a uniform flow of sample gas at atmospheric pressure, and isolates the sample from the surrounding atmosphere. A stainless steel needle valve (or pressure regulator) is placed between the source valve and the sampling chamber for the purpose of throttling the sample flow. Flow rate should approximate one to two volume changes per minute, or, at minimum, provide positive exit gas flow throughout the detector tube sampling period.

~

PLASTICONO T N E R ~ SUITABLEFLEXIBLE TUBING

NOTE 2--A suitable sampling chamber may be devised from a polyethylenewash bottle of nominal 500-mL(16-oz)or l-L (32-oz) size. The wash bottle's internal delivery tube provides for delivery of the sample gas to the bottom of the bottle. A 12.5-ram (I/2-in.) hole cut in the bottle's cap provides access for the detector tube and vent for the purge gas (Fig. l). (An alternate flow-throughsampler may be fashioned using a l-gal Ziploc-type food storage bag. The flexibleline enters one corner of the bag's open end and extends to the bottom of the bag. The opposite corner of the open end is used for tube access and sample vent. The remainder of the bag's top is sealed shut. The basic procedure for the sampler in Fig. l applies.) NOTE 3--An alternate sampling container is a collectionbag made of a material suitable for the collection of natural gas (for example, Mylar). The sampling bag should have a minimum capacity of 2 L. 6. Procedure 6.1 Select a sampling point that will provide access to a representative sample of the gas to be tested (for example, source valve on the main line). The sample point should be on top of the pipeline, and equipped with a stainless steel sample probe extending into the middle third of the pipeline. Open the source valve momentarily to clear the valve and connecting nipple of foreign materials. 6.2 Install needle valve (or pressure regulator) at the source valve outlet. Connect sampling chamber using the shortest length of flexible tubing possible (Fig. 1). Avoid using tubing that reacts with or absorbs H2S, such as copper or natural rubber. Use materials such as TFE-fluorocarbon, vinyl, polyethylene, or stainless steel. 6.3 Open source valve. Open needle valve enough to obtain positive flow of gas through chamber, in accordance with 5.3. Purge the container for at least 3 min. (Fig. l). NoTe 4--If a collection bag is used instead of a sampling chamber, follow 6.1 and 6.2, substituting the bag for the chamber. Follow 6.3, disconnecting the bag when filled. Deflate the bag to provide a purge, and fill a second time to provide a sample. The bag must be flattened completelyprior to each filling (Note 3). 6.4 Before each series of measurements, test the pump for leaks by operating it with an unbroken tube in place. Consult the manufacturer's instructions for leak check procedure details and for maintenance instruction, if leaks are detected. The leak check typically takes one minute. 6.5 Select a detector tube with the range that best encompasses the expected H2S concentration. Reading accuracy is improved when the stain length extends into the upper half of the calibration scale. Consult manufacturer's guidelines

729

~]~

~-- PUMP

~

TUBEACCEEE • GAE VENT Ii

GAS 8AMPLING

~!

CHAMBER

~.._._

~

[ ~

DETECTOR TUBE

FIG. 1 ApparatusSchematic for using multiple strokes to achieve a lower range on a given tube. 6.6 Break off the tube tips and insert the tube into the pump, observing the flow direction indication on the tube. Place the detector tube into the sampling chamber through the access hole, so that the tube inlet is near the chamber center (Fig. l). NOTe 5--Detector tubes have temperature limits of 0 to 40"C (32 to 104°F), and sample gases must remain in that range throughout the test. Cooling probes are available for sample temperatures exceeding40"C. 6.7 Operate the pump to draw the measured sample volume through the detector tube. Observe tube instructions when applying multiple strokes. Assure that a positive flow is maintained throughout the sample duration at the sampling chamber gas exit vent. Observe tube instructions for proper sampling time per pump stroke. The tube inlet must remain in position inside the sampling chamber until the sample is completed. Many detector tube pumps will have stroke finish indicators that eliminate the need to time the sample. NOTe 6--Ira collectionbag is used, the sample is drawn from the bag via a flexible tubing connection. Do not squeeze the bag during sampling. Allow the bag to collapse under pump vacuum, so that the pump's flow characteristics are not altered. 6.8 Remove the tube from the pump and immediately read the H2S concentration from the tube's calibration scale, or from the charts provided in the box of tubes. Read the tube at the maximum point of the stain. If "channeling" has occurred (non-uniform stain length), read the maximum and minimum stain lengths and average the two readings. NOTe 7--If the calibration scale is not printed directly on the detector tube, be sure that any separate calibration chart is the proper match for the tube in use.

O o 4a10

NOTE 8--Although the amount of chemicals contained in detector tubes is very small, the tubes should not be disposed of carelessly. A general disposal method includes soaking the opened tubes in water prior to tube disposal. The water should be pH neutralized prior to its disposal.

toring. 4 NIOSH tested tubes at 1/2, 1, 2, and 5 times the Threshold Limit Value (TLV), requiring ±25 % accuracy at the three higher levels, and ±35 % at the V2TLV level.5 (For example, H2S with a TLV of l0 ppm was tested at levels of 5, 10, 20, and 50 ppm.) The higher tolerance allowed at the low level was due to the loss of accuracy for shorter stain lengths.3 NIOSH discontinued this program in 1983, and it was picked up by the Safety Equipment Institute (SEI) in 1986. 7.1.1 The Gas Processors Association standard No. 2377 for natural gas testing via H2S detector tubes summarizes detector tube accuracy testing in natural gas in which all reported results are within ±23 %. 7.2 Repeatability--Duplicate results by the same operator under the same test conditions, should produce results within ±10 % between 3 and 120 ppm H2S and ±5 % between 0.05 and 5 % H2S (see GPA No. 2377), Repeatability is optimized when all tests using a single brand are conducted with detector tubes of the same lot number.

7. Precision and Bins

8. Keywords 8.1 gaseous fuels; natural gas

7.1 The accuracy of detector tube systems is generally considered to be ±25 %. This value is based on programs conducted by the National Institute of Occupational Safety and Health (NIOSH) in certifying detector tubes for low level contaminants in air, adapted to worker exposure moni-

4 Septon, J. C. and Wilczek, T., *'Evaluation of Hydrogen Sulfide Detector Tubes," App. Ind. Hys., Yol. I, No. 4, 11/86. S"NIOSH Certification Requirements for Gas Detector Tube Units," NIOSH/TC/A-012, 7/78.

6.9 If the number of strokes used differs from the number of strokes specified for the calibration scale, correct the reading, as below: specified strokes ppm (corrected) ffi ppm (reading) x actualstrokes 6.10 Record the reading immediately, along with the gas temperature and the barometric pressure. Observe any temperature corrections supplied in the tube instructions. Altitude corrections become significant at elevations above 2000 ft. Correct for barometric pressure, as below: 760 mm H~g ppm (corrected)ffi ppm (reading) × barometric pressure m mm Hg

The American Society for Testing end Materials takes no pesitlon respecting the validity of any patent rights auerted in connection with any item mentioned in this standard. Users of this Manderd are e ~ l y advised that determination of the vatlditF of any 8uoh patent rights, and the risk of Infringement of such rights, ere entirely their own respormlbitity. This standard is subject to revision st any time by the responsible technical committee and must be reviewed every five years and If not revised, either reapproved or withdrawn. Your conmlante are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend, ff you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 1918 Race St., Philadelphia, PA 19103.

730

q~[~ Designation: D 4815 - 94a Standard Test Method for Determination of MTBE, ETBE, TAME, DIPE, tertiary-Amyl Alcohol and C 1 to C4 Alcohols in Gasoline by Gas Chromatography 1 This standard is issued under the fixed designation D 4815; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (4) indicates an editorial change since the last revision or reapproval. o NoTE--Paragraph 15.2 was corrected editorially and the designation date was changed effective July 25, 1994.

1. Scope 1.1 This test method is designed for the determination of ethers and alcohols in gasolines by gas chromatography. Specific compounds determined are: methyl tert-butylether (MTBE), ethyl tert-butylether (ETBE), tert-amylmethylether (TAME), diisopropylether (DIPE), methanol, ethanol, isopropanol, n-propanol, isobutanol, tert-butanol, secbutanol, n-butanol, and tert-pentanol (tert-amylalcohol). 1.2 Individual ethers are determined from 0.1 to 20.0 mass percent. Individual alcohols are determined from 0.1 to 12.0 mass pe'rcent. Equations used to convert to mass percent oxyger~ and to volume % of individual compounds are provided. 1.3 Alcohol-based fuels such as M-85 and E-85, MTBE product, ethanol product and denatured alcohol are specifically excluded from this method. The methanol content of M-85 fuel is considered beyond the operating range of the system. 1.4 Benzene, while detected, cannot be quantified using this test method and must be analyzed by alternate methodology (Test Method D 3606 or D 4420). 1.5 SI (metric) units are preferred and used throughout this standard. Alternate units, in common usage, are also provided to increase clarity and aid the users of this test method. 1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

D 3606 Test Method for Benzene and Toluene in Finished Motor and Aviation Gasoline by Gas Chromatography 3 D 4052 Test Method for Density and Relative Density of Liquids by Digital Density Meter 3 D4057 Practice for Manual Sampling of Petroleum and Petroleum Products 3 D 4307 Practice for Preparation of Liquid Blends for Use as Analytical Standards 3 D 4420 Test Method for Aromatics in Finished Gasoline by Gas Chromatography 3 3. Terminology 3. I Descriptions of Terms Specific to This Standard: 3.1.1 low volume connector--a special union for connecting two lengths of tubing 1.6 mm inside diameter and smaller. Sometimes this is referred to as zero dead volume union. 3.1.2 MTBE--methyl tertiary-butylether. 3.1.3 ETBEmethyl tertiary-butylether. 3.1.4 TAME--tertiary-amyl methylether. 3.1.5 DIPEmdiisopropylether. 3.1.6 tertiary-amyl alcohol--tertiary-pentanol. 3.1.7 oxygenate--aqy oxygen-containing organic compound which can be used as a fuel or fuel supplement, for example, various alcohols and ethers. 3.1.8 split ratio---in capillary gas chromatography, the ratio of the total flow of carrier gas to the sample inlet versus the flow of the carrier gas to the capillary column, expressed by split ratio = (S + C)/C (I) where: S ffi flow rate at the splitter vent, and C = flow rate at the column outlet. 3.1.9 TCEP-- 1,2,3-tris-2-cyanoethoxypropane--a gas chromatographic liquid phase. 3.1.10 WCOT--a type of capillary gas chromatographic column prepared by coating the inside of the capillary with a thin film of stationary phase.

2. Referenced Documents 2.1 ASTM Standards: D 1298 Test Method for Density, Relative Density (Specific Gravity), or API Gravity of Crude Petroleum and Liquid Petroleum Products by Hydrometer Method 2 D 1744 Test Method for Water in Liquid Petroleum Products by Karl Fischer Reagent 2

4. Summary of Test Method 4.1 An appropriate internal standard such as 1,2dimethoxyethane (ethylene glycol dimethyl ether) is added to

This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee 1302.04 on Hydrocarbon Analysis. Current edition approved July 25, 1994. Published September 1994, Originally published as D 4815 - 89. Last previous edition D 4815 - 94. 2 Annual Book of ASTM Standards, Vol 05.01.

3 Annual Book of ASTM Standards, Vol 05.02.

731

(@) D 4815 the sample which is then introduced into a gas chromatograph equipped with two columns and a column switching valve. The sample first passes onto a polar TCEP column which elutes lighter hydrocarbons to vent and retains the oxygenated and heavier hydrocarbons. 4.2 After methylcyclopentane, but before DIPE and MTBE elute from the polar column, the valve is switched to backflush the oxygenates onto a WCOT non-polar column. The alcohols and ethers elute from the non-polar column in boiling point order, before elution of any major hydrocarbon constituents. 4.3 After benzene and TAME elute from the non-polar column, the column switching valve is switched back to its original position to backflush the heavy hydrocarbtms. 4.4 The eluted components are detected by a flame ionization or thermal conductivity detector. The detector response, proportional to the component concentration, is recorded; the peak areas are measured; and the concentration of each component is calculated with reference to the internal standard. 5. Significance and Use 5.1 Ethers, alcohols, and other oxygenates can be added to gasoline to increase octane number and to reduce emissions. Type and concentration of various oxygenates are specified and regulated to ensure acceptable commercial gasoline quality. Drivability, vapor pressure, phase separation, exhaust and evaporative emissions are some of the concerns associated with oxygenated fuels. 5.2 This test method is applicable to both quality control in the production of gasoline and for the determination of deliberate or extraneous oxygenate additions or contamination.

6. Apparatus 6.1 Chromatograph--While any gas chromatographic system, which is capable of adequately resolving the individual ethers and alcohols that are presented in Table l, can be used for these analyses, a gas chromatographic instrument TABLE 1 Pertinent Physical Constants and Retention CharactadsUcs for TCEP/WCOT Column Set Conditions as in Table 2

Component

Water Methano~ Ethanol Isolxopan~ tart-Butanol n-Propano~

MTBE sec-Butenol DIPE Isol~tenol ETBE tert-Pentanol 1,2-Dimethoxyethene

Relative Retention Retention Time Time, Min. (MTBE - (DME = 1.00) 1.00)

Relative Molecular Densatyat W e i g h t 15.56/ 15,56°C

2.90 3.15 3.48 3.63 4.15 4,56 5.04 5.36 5.76 6.00 8.20 6.43 6.80

0.58 0.63 0.69 0.76 0.82 0.90 1.00 1.06 1.14 1.19 1.23 1.28 1.35

0.43 0.46 0.51 0.56 0.61 0.67 0.74 0.79 0.85 0.88 0.91 0.95 1.00

18,0 32.0 46.1 60.1 74.1 60,1 88.2 74.1 102.2 74.1 102.2 88.1 90.1

1.000 0.7963 0.7939 0.7699 0.7922 0.8080 0.7460 0.8114 0.7300 0.8058 0.7452 0.6170 0,8720

7.04 7.41 8.17

1.40 1.47 1.62

1.04 1.09 1,20

74.1 78,1 102.2

0.8137 0.8830 0.7758

TABLE 2

Chromatographic Operation CondiUons

Temperatures Column Oven Injector, °C OetectorwTCD, °C wFID, °C Valve °C

(DME) rvButeno~ Benzene TAME

which can be operated at the conditions given in Table 2, and having a column switching and backflushing system equivalent to Fig. l has been found acceptable. Carrier gas flow controllers shall be capable of precise control where the required flow rates are low (Table 2). Pressure control devices and gages shall be capable of precise control for the typical pressures required. 6. 1.2 Detector--A thermal conductivity detector or flame ionization detector, can be used. The system shall have sufficient sensitivity and stability to obtain a recorder deflection of at least 2 mm at a signal-to-noise ratio of at least '5 to l for 0.005 volume % concentration of an oxygenate. 6.1.3 Switching and Backflushing ValvenA valve, to be located within the gas chromatographic column oven, capable of performing the functions described in Section 11 and illustrated in Fig. 1. The valve shall be of low volume design and not contribute significantly to chromatographic deterioration. 6.1.3.1 Valco Model No. A 4CIOWP, 1.6 mm (1/16 in.) fittings. This particular valve was used in the majority of the analyses used for the development of Section 15. 6.1.3.2 ValcoModelNo. CIOW, 0.8 mm ('/32 in.) fittings. This valve is recommended for use with columns of 0.32 mm inside diameter and smaller. 6.1.3.3 Some gas chromatographs are equipped with an auxiliary oven which can be used to contain the valve and polar column. In such a configuration, the nonpolar column is located in the main oven and the temperature can be adjusted for optimum oxygenates resolution. 6.1.4 An automatic valve switching device must be used to ensure repeatable switching times. Such a device should be synchronized with injection and data collection times. 6.1.5 Injection System--The chromatograph should be equipped with a splitting-type inlet device if capillary columns or flame ionization detection are used. Split injection is necessary to maintain the actual chromatographed sample size within the limits of column and detector optimum efficiency and linearity. 6.1.5.1 Some gas chromatographs are equipped with oncolumn injectors and autosamplers which can inject small samples sizes. Such injection systems can be used provided that sample size is within the limit of the column and detectors optimum efficiency and linearity. 6.1.5.2 Microlitre syringes, automatic syringe injectors, and liquid sampling valves have been used successfully for introducing representative samples into the gas chromatographic inlet. 6.2 Data Presentation or Calculation, or Both: 6.2.1 Recorder--A recording potentiometer or equivalent with a full-scale deflection of 5 mV or less can be used to

Flows, mL/min 60 200 200 250 60

to injector 75 Column 5 Auxiliary 3 Makeup 18

Carrier Gas: Helium Samplesize, lZLA Split ratio Backflush,rain Valve reset time Total Analysis time

1.0-3.0 15:1 0.2-0.3 8-10 rain 18-20 mln

A Sample size must be adjusted so that alcohols in the range of 0.1 to 12.0 mass "/~and ethers in the range of 0.I to 20.0 mass "/, are eluted from the column and measured ilnsedyat the detector. A semple size of 1.0 ~L has been introduced in most cases.

732

@ o 4a s

,yoo

ADJUSTABLE

•

~-

/.

I

"

POLAR (TCEP)

~

I /

IX,<

le

zo

30

40

SO

SO

~a

tO

IO

lee

NINUII~S

FIG. 2 Analysesof Oxygenates in Gasoline Example

ChromatogramShowing Oxygenates

L

FLOW---~ CONTROLLER

Valve

in R E S E T

AD JLrSTABLE

RZSTRXCrOR

COLU~

VZ~

~

NON-POLAR

~"

remaining hydrocarbons are backflushed onto the non-polar column in 6.3.2. Any column with equivalent or better chromatographic efficiency and selectivity to that described in 6.3.1.1 can be used. The column shall perform at the same temperature as required for the column in 6.3.2, except if located in a separate auxiliary oven as in 6.1.3.3. 6.3.1.1 TCEP Micro.Packed Column, 4 560 mm (22 in.) by 1.6 mm (1/16 in.) outside diameter by 0.38 mm (0.015 in.) inside diameter stainless steel tube packed with 0.14 to 0.15 g of 20 % (mass/mass) TCEP on 80/100 mesh Chromosorb P(AW). This column was used in the cooperative study to provide the precision and bias data referred to in Section 15. 6.3.2 Non-Polar (Analytical) ColumnmAny column with equivalent or better chromatographic efficiency and selectivity to that described in 6.3.2.1 and illustrated in Fig. 2 can be used. 6.3.2.1 WCOTMethyl Silicone Column, 30 m (1181 in.) long by 0.53 mm (0.021 in.) inside diameter fused silica WCOT column with a 2.6 ~tm film thickness of cross-linked methyl siloxane. This column was used in the cooperative study to provide the precision and bias data referred to in Section 15.

Position

y

POcLtR- ~ TCEP)

,.u.~

(T(~"--"

rJ'-~-<-I-

I N J ECT OR

7. Reagents and Materials 7.1 Carrier Gas--Carder gas appropriate to the type of detector used. Helium has been used successfully. The minimum purity of the carder gas used must be 99.95 mol %. 7.2 Standards for Calibration and Identification--Stan. dards of all components to be analyzed and the internal standard are required for establishing identification by retention time as well as calibration for quantitative measurements. These materials shall be of known purity and free of the other components to be analyzed.

L_FLOW CONTROLLER Valve

i n BACKFLUSH P o s i t i o n

FIG. 1 Analysis of Oxygenates in Gasoline Schematic of Chromatographic System

monitor detector signal. Full-scale response time should be 1 s or less with sufficient sensitivity and stability to meet the requirements of 6.1.2. 6.2.2 Integrator or Computer--Means shall be provided for determining the detector response. Peak heights or areas can be measured by computer, electronic integration or manual techniques. 6.3 Columns, Two as Follows: 6.3.1 Polar Column--This column performs a preseparation of the oxygenates from volatile hydrocarbons in the same boiling point range. The oxygenates and

NOTE 2: Warning--These materials are flammable and can be harmful or fatal if ingestedor inhaled. 7.3 Methylene Chloride--Used for column preparation. Reagent grade free of non-volatile residue. 4 Available from Hewtett Packard Co., Avondale, PA,

733

~

D 4815

NOTE 3: Warning--Harmful if inhaled. High concentrations may cause unconsciousnessor death.

8. Preparation of Column Packings 8.1 TCEP Column Packing." 8.1.1 Any satisfactory method, used in the practice of the art that will produce a column capable of retaining the C 1 to C4 alcohols and MTBE, ETBE, DIPE and TAME from components of the same boiling point range in a gasoline sample. The following procedure has been used successfully. 8.1.2 Completely dissolve 10 g of TCEP in 100 mL of methylene chloride. Next add 40 g of 80/100 mesh Chromosorb P(AW) to the TCEP solution. Quickly transfer this mixture to a drying dish, in a fume hood, without scraping any of the residual packing from the sides of the container. Constantly, but gently, stir the packing until all of the solvent has evaporated. This column packing can be used immediately to prepare the TCEP column. 9. Sampling 9.1 Every effort should be made to ensure that the sample is representative of the fuel source from which it is taken. Follow the recommendations of Practice D 4057 or its equivalent when obtaining samples from bulk storage or pipelines. 9.2 Upon receipt in the laboratory, chillthc sample in its original container to 0 to 5°C (32 to 40°F) before any subsampling is performed. 9.3 If necessary, transfer the chilled sample to a vapor tightcontainer and store at 0 to 5°C (32 to 40°F) until needed for analysis. 10. Preparation of Micro-Packed TCEP Column 10.1 Wash a straight 560 mm length of 1.6 mm outside diameter (0.38 mm inside diameter) stainless steel tubing with methanol and dry with compressed nitrogen. 10.2 Insert 6 to 12 strands of silvered wire, a small mesh screen or stainless steel flit inside one end of the tube. Slowly add 0.14 to 0.15 g of packing material to the column and gently vibrate to settle the packing inside the column. When strands of wire are used to retain the packing material inside the column, leave 6.0 mm (0.25 in.) of space at the top of the column. 10.3 Column Conditioning--Both the TCEP and WCOT columns are to be briefly conditioned before use. Connect the columns to the valve (see I I. l) in the chromatographic oven. Adjust the carrier gas flows as in I 1.3 and place the valve in the RESET position. After several minutes, increase the column oven temperature to 120"C and maintain these conditions for 5 to l0 min. Cool the columns below 60"C before shutting off the carder flow. 11. Preparation of Apparatus and Establishment of Conditions 11.1 Assembly--Connect the WCOT column to the valve system using low volume connectors and narrow bore tubing. It is important to minimize the volume of the chromatographic system that comes in contact with the sample, otherwise peak broadening will occur. l l.2 Adjust the operating conditions to those listed in Table 2, but do not turn on the detector circuits. Check the

system for leaks before proceeding further. 11.2.1 If different polar and nonpolar columns are used, or capillary columns of smaller ID are used, or both, it can be necessary to use different optimum flows and temperatures. I 1.3 Flow Rate Adjustment: I 1.3. l Attach a flow measuring device to the column vent with the valve in the RESET position and adjust the pressure to the injection port to give 5.0 mL/min flow (14 psig). Soap bubble flow meters are suitable. 11.3.2 Attach a flow measuring device to the split injector vent and adjust the flow from the split vent using the A flow controller to give a flow of 70 mL/min. Recheck the column vent flow set in I 1.3. l and adjust if necessary. I 1.3.3 Switch the valve to the BACKFLUSH position and adjust the variable restrictor to give the same column vent flow set in I 1.3.1. This is necessary to minimize flow changes when the valve is switched. 11.3.4 Switch the valve to the inject position RESET and adjust the B flow controller to give a flow of 3.0 to 3.2 mL/min at the detector exit. When required for the panicular instrumentation used, add makeup flow or TCD switching flow to give a total of 21 mL/min at the detector exit. l l.4 When a thermal conductivity detector is used, turn on the filament current and allow the detector to equilibrate. When a flame ionization detector is used, set the hydrogen and air flows and ignite the flame. 11.5 Determine the Time to BackflushmThe time to backflush will vary slightly for each column system and must be determined experimentally as follows. The start time of the integrator and valve timer must be synchronized with the injection to accurately reproduce the backflush time. I 1.5. l Initially assu~e a valve BACKFLUSH time of 0.23 rain. With the valve RESET, inject l to 3 pL of a blend containing at least 0.5 % or greater oxygenates (7.3), and simultaneously begin timing the analysis. At 0.23 rain, rotate the valve to the BACKFLUSH position and leave it there until the complete elution of TAME is realized. Record this time as the RESET time, which is the time at which the valve is returned to the RESET position. When all of the remaining hydrocarbons are backflushed the signal will return to a stable baseline and the system is ready for another analysis. The chromatogram should appear similar to the one illustrated in Fig. 2. I 1.5. I. l Ensure that the BACK.FLUSH time is sufficient to quantitatively transfer the higher concentrations of the ethers, specifically MTBE, into the nonpolar column. l 1.5.2 It is necessary to optimize the valve BACKFLUSH time by analyzing a standard blend containing oxygenates. The correct BACKFLUSH time is determined experimentally by using valve switching times between 0.20 and 0.35 min. When the valve is switched too soon, C5 and lighter hydrocarbons are backflushed and are co-eluted in the C4 alcohol section of the chromatogram. When the valve BACKFLUSH is switched too late, part or all of the ether component (MTBE, ETBE or TAME) is vented resulting in an incorrect ether measurement. I 1.5.2. l DIPE may require a BACKFLUSH time slightly shorter than the other ethers. The system may require reoptimization if the analysis of DIPE is required.

734

~) D 4815 correlation ta value for each oxygenate calibration. The ra value should be at least 0.99 or better, ta is calculated as follows: (Zxy)~

11.5.3 To facilitate setting BACKFLUSH time, the column vent in Figure 1 can be connected to a second detector (TCD or FID) as described in Test Method D 4420 and used to set BACKFLUSH TIME based on the oxygenates standard containing the ethers of interest.

=

2)

where:

12. Calibration and Standardization 12.1 Identification--Determine the retention time of each component by injecting small amounts either separately, or in known mixtures or by comparing the relative retention times with those in Table 1. 12.1.1 In order to ensure minimum interference from hydrocarbons, it is strongly recommended that a fuel devoid of oxygenates be chromatographed to determine the level of any hydrocarbon interference. 12.2 Preparation of Calibration Samples--Prepare multicomponent calibration standards o f the oxygenates and concentration ranges of interest by mass according to Test Method D 4307. For each oxygenate, prepare a minimum of five calibration standards spanning the range of the oxygenate in the samples. As an example, for full range calibration, 0.1, 0.5, 2, 5, 10, 15, and 20 mass percent of each oxygenate may be used. Before preparing the standards, determine the purity of the oxygenate stocks and make corrections for the impurities found. Whenever possible, use stocks of at least 99.9 % purity. Correct the purity of the components for water content determined by Test Method D 1744. To minimize evaporation of light components, chill all chemicals and gasoline used to prepare standards. Prepare standards by transferring a fixed volume of oxygenates using pipettes or eye droppers (for volumes below one volume percent) to 100 m L volumetric flasks or septum capped vials as follows. Cap and record the tare weight of the volumetric flask or vial to 0.1 mg. Remove the cap and carefully add the oxygenate to the flask or vial. Do not contaminate with sample the part within the flask or vial which contacts the cap. Cap and record the net mass (Wi) to 0.1 mg of the oxygenate added. Repeat the addition and weighing procedure for each oxygenate of interest. Similarly, add 5 mL of the internal standard (DME) and record its net mass (Ws) to 0.I mg. Dilute each standard to 100.0 m L with oxygenatefree gasoline or a mixture of hydrocarbons such as isooctane/ mixed xylenes (63.35 volume percent). Do not exceed 30 volume percent for all oxygenates, including the internal standard added. Store the capped calibrations standards below 5"C (40*F) when not in use. 12.3 Standardization: 12.3.1 Run the calibration standards and establish the calibration curve for each oxygenate. Plot the response ratio (rspi): rsp, = (Ai/As) (2) where: Ai = area of oxygenate, and As = area of internal standard. as the y-axis versus the amount ratio (amt,): amt, = (Wi/Ws)

(4)

(zx2)(zy

x = x, - x y = Y~- Y

(5) (6)

and: X~ = amt~ ratio data point, X = average values for all (amt,) data points, Yt = corresponding rsp~ ratio data point, and = average values for all (rspi) data points. 12.3.2 Table 3 gives an example on the calculation of r 2 for an ideal data set X i and Yi: 12.3.3 For each oxygenate i calibration data set, obtain the linear !east-squares fit equation in the form: (rsp,) = (mi)(amt,) + b, (7) where: (rspi) = response ratio for oxygenate i (y-axis), m~ = slope of linear equation for oxygenate i, amti = amount ratio for oxygenate i (x-axis), and b; = y-axis intercept. 12.3.4 The values m~ and b~ are calculated as follows: m, = Zxy/Zx 2 (8) and b~ = .~ - mfi 12.3.5 For the example in Table 3: m~ = Z/to= 0.5

(9) (10)

and b; = ~ - ~ f i

1.5 - (0.5)(3) = 0

=

(11)

Therefore, the least-squares fit (Eq 7) for the above example in Table 3 is: (rsp,) = 0.5 amt i + 0 (12) NOTE 5uNormally the b, value is not zero and may be either positive or negative. Figure 3 gives an example of a linear least-squares fit for MTBE and the resulting equation in the form of Eq 7 above.

12.3.6 For an optimum calibration, the absolute value of the y-intercept bi must be at a minimum. In this case, A; approaches zero when wi is less than 0.1 mass percent. The equation to determine the mass percent oxygenate i or wi, reduces to Eq 13. The y-intercept can be tested using Eq 13 below: TABLE 3 Xi

Yi

1.0 0.5 2.0 1.0 3.0 1.5 4.0 2.0 5.0 2.5 £=3.0,9=1.5

(3)

where: Wi --- mass of oxygenate, and Ws - mass of internal standard. as the x-axis calibration curves for each oxygenate. Check the

Example Calculation of Correlation Coefficient x == X , -

-2.0 -1,0 0.0 +1.0 +2.0

r==

X

Y = Y~ - V

-1.0 -0.5 0.0 0.5 1.0

(Zxy) =

(Zx=XZy~')

735

==

xy

x=

2.0 0.5 0.0 0.5 2.0 (~=25.0 25.C (10.0X2.5)

= 1.0

y=

4.0 1.0 1.0 0.25 0.0 0.0 1.0 0.25 4.0 1.0 Zx==lO.O ¢ ~ = 2 . 5

(~ D 4815 wi = (b,/mi)( W s/Wg)100 % (13) where: w~ = mass % oxygenate i, where w~ is <0.1 mass %, Ws = mass of internal standard added to the gasoline samples g, and W8 = mass of gasoline samples, g. NOTE 6--Since in practice W , and Wg vary slightly from sample to sample, use average values.

12.3.7 The following gives an example of the calculation for the y-intercept (bi) test using Fig. 3 for oxygenate i (MTBE) for which bi = 0.015 and m,. ffi 1.83. From 13.1, a typical sample preparation may contain approximately Ws = 0.4 g (0.5 mL) of internal standard and approximately Wa = 7 g (9.5 mL) of a gasoline sample. Substituting these values into Eq 13 yields: w i ffi (0.015/1.83)(0.4 g r a m s / 7 g r a m s ) 100 %

(14)

= 0.05 mass % 12.3.8 Since w; is less than 0.1 mass percent, the y-intercept bi has an acceptable value for MTBE. Similarly, determine w, for all other oxygenates. For all oxygenates, w~ must be less than 0.1 mass percent. If any of the w; values are greater than O. 1 mass percent, rerun the calibration procedure for oxygenate i or check instrument parameters and hardware or check for hydrocarbon interferences. 13. Procedure 13.1 Preparation o f S a m p l e - - T r a n s f e r 0.5 mL of internal standard ( W s ) by a volumetric pipette into a tared and capped 10 mL volumetric flask. Record weight to nearest 0.1 mg. Record the net mass of the internal standard added. Retare the capped flask. Fill the 10 mL volumetric flask to volume with sample, cap and record the net mass (Wg) to the nearest 0.1 mg of the sample added. Mix thoroughly and

inject into the gas chromatograph. If using an automatic sampler then transfer an aliquot of the solution into a glass gas chromatographic (GC) vial. Seal the GC vial with a Teflon-lined septum. If the sample is not immediately analyzed, store below 5°C (40°F). 13.2 Chromatographic Analysis--Introduce a representative aliquot of the sample, containing internal standard, into the gas chromatograph using the same technique and sample size as used for the calibration analysis. An injection volume of 1.0 to 3.0 ~tL with a 15:1 split ratio has been.used successfully. Start recording and integrating devices in synchronization with sample introduction. Obtain a chromatogram or integrated peak report or both which displays the retention times and integrated area of each detected component. 13.3 Interpretation o f C h r o m a t o g r a m - - C o m p a r e the retention times of sample components to those of the calibration analysis to determine the identities of oxygenates present.

14. Calculationsand Reporting 14.1 Mass Concentration o f Oxygenates--After identifying the various oxygenates measure the area of each oxygenate peak and that of the internal standard. From the least-squares fit calibrations, as depicted in the MTBE example in Fig. 3, calculate the mass of each oxygenate (IV,.) in the gasoline samples using the response ratio (rsp,) of the areas of the oxygenate to that of the internal standard as follows: rsp, ffi (m~)(amt,) + b i (7) where: mi ffi slope of the linear fit, b~ ffi y-intercept, and amt, ffi amount ratio as defined by Eq 3.

MTIIE

or

amt i ffi ~

= (rsp, - bi)/m i

(15)

or

Wi ffi [(rspi- bj)/mi]Ws = [(Ai/As - bi)/mi] Ws

(16) (17)

To obtain mass percent (w,) results for each oxygenate: Wi(100 %) w, ffi wa (18)

o

le only .w

/ / ....

where: W8 = weight of gasoline sample. 14.2 Report the mass percent of each oxygenate to the nearest 0.01 mass percent. 14.3 Volumetric Concentration o f O x y g e n a t e s - - I f the volumetric concentration of each oxygenate is desired, calculate the volumetric concentration according to Eq 14:

~P ratio=1_'83(amtrafl°)'O'01$ 1-'2 - 1.000 025 . . . .

1.~ . . . .

v, ffi wifD/~

kO,/

125 " " "

where: wi -- mass percent of each oxygenate as determined using Eq 13, Vi = volume percent of each oxygenate to be determined,

amt ratio FIG. 3

(19)

A Least-Squares Fit Calibration for MTBE

736

(@) D 4815 TABLE 4

Precision Interval as Determined from Cooperative Study Data Repeatabihty

Component Wt. % 0.20 0.50 1.00 2.00 3.00 4.00 5.00 6,00 10.00 12.00 14.00 16.00 20.00

MEOH

EtOH

iPA

tBA

nPA

MTBE

sBA

DIPE

iBA

ETBE

tAA

nBA

TAME

0.04 0.06 0.09 0.14 0.17 0.20 0.23 0.26 0.35 0.39

0.02 0.04 0.06 0.09 0.12 0.14 0.16 0,18 0.24 0.27

0.02 0.03 0.04 0.06 0.07 0.09 0.10 0.11 0.15 0.16

0.02 0.03 0.04 0.06 0.07 0.09 0.10 0.11 0.15 0.16

0.01 0.02 0.03 0.05 0.06 0.07 0.08 0.08 0.11 0.12

0.02 0.03 0.05 0.07 0.09 0.11 0.12 0.14 0.18 0.20 0.22 0.24 0.27

0.01 0.02 0.03 0.05 0.06 0.07 0.08 0.09 0.12 0.14

0,03 0.05 0,08 0.12 0.15 0.17 0.20 0.22 0.29 0.32 0.35 0.38 0.43

0.03 0.05 0,08 0.12 0.15 0.17 0,20 0.22 0.29 0.32

0.01 0.03 0.05 0.09 0.12 0.16 0.19 0.22 0.33 0.38 0.44 0.49 0.58

0.02 0.03 0.04 0,06 0.08 0.09 0.11 0.12 0.16 0.18

0.02 0.04 0.06 0.09 0.12 0.14 0.16 0.18 0.24 0.27

0.02 0.03 0.05 0,08 0.11 0.13 0.15 0.17 0.25 0.29 0.32 0.35 0.41

Total Oxygen

0.02 0.05 0.08 0.12 0.15

Reproducibility Component Wt. Y= 0.20 0.50 1.00 2.00 3.00 4.00 5.00 6.00 10.00 12.00 14.00 16,00 20.00

MEOH

EtOH

iPA

tBA

nPA

MTBE

sBA

DIPE

iBA

ETBE

t/~

nBA

TAME

0.14 0,24 0.37 0.57 0.72 0.86 0.99 1.10 1,51 1.68

0.09 0.16 0.23 0.34 0.43 0.51 0.58 0.64 0.86 0.95

0.14 0.26 0.42 0.67 0.80 1.06 1.23 1.40 1.97 2.22

0.07 0.12 0.19 0.30 0.40 0.48 0.56 0.63 0.89 1.00

0.04 0.07 0.11 0.16 0.21 0.24 0.28 0.31 0.41 0.45

0.04 0.08 0.12 0.19 0.25 0,30 0.35 0.40 0.56 0.63 0,70 0.77 0.89

0.15 0.28 0.44 0.70 0.92 1.11 1,29 1.46 2.06 2.33

0.14 0.26 0.42 0.67 0.88 1.06 1.23 1.40 1.97 2.22 2.46 2.69 3.13

0.14 0.26 0.42 0,67 0.88 1.06 1.23 1.40 1.97 2.22

0.11 0.21 0.46 0,61 0.83 1.03 1.22 1.41 2.07 2.38 2.68 2.96 3.51

0.06 0.10 0.15 0.22 0.28 0,33 0.38 0.42 0.56 0.62

0.09 0.15 0.22 0.33 0.41 0.49 0.55 0.61 0.82 0.91

0.14 0.22 0.31 0.44 0.54 0.63 0.70 0.77 1.00 1.10 1.19 1.28 1.43

D,-= relative density at 15.56°C (60*F) of the individual oxygenate as found in Table 2, and Df= relative density of the fuel under study as determined by Test Method D 1298 or D 4052. 14.4 Report the volume percent of each oxygenate to the nearest 0.01 volume percent. 14.5 Mass Percent Oxygen--To determine the oxygen content of the fuel, convert and sum the oxygen contents of all oxygenated components determined above according to the following equation:

Total Oxygen

0.09 0.22 0.36 0.52 0.70

15. Precision and Bias s 15.1 Precision--The precision of this test method as determined by a statistical examination of interlaboratory test results is as followg: 15.1.1 Repeatability--The difference between successive results obtained by the same operator with the same apparatus under constant operating conditions on identical test materials would, in the long run, in the normal and the correct operation of the test method exceed the following values in Table 4 only in one case in twenty. Repeatability Estimates for Oxygenates in Gasoline

W~o, = Z

wI

x

16.0

x

Nl

Component Methanol (MeOH) Ethanol (EtOH) Bopropanol (iPA) tert-Butanol (tBA) n-Propanol (nPA) MTBE see-Butanol (sBA) DIPE lsobutanol (iBA) ETBE tert-Pentanol (tAA) n-Butanol (nBA) TAME Total Oxygen

(20)

Ml

or

Wtot=

w~x 16.0xN~

M,

+

w2 x 1 6 . 0 x N 2 M2

+...

(21)

where: w, = mass percent of each oxygenate as determined using Eq 13, Wto, ffi total mass percent oxygen in the fuel, M, -- molecular mass of the oxygenate as given in Table 2, 16.0 -- atomic mass of oxygen, and N~ -- number of oxygen atoms in the oxygenate molecule. 14.6 Report the total mass percent of oxygen in the fuel to the nearest 0.01 mass percent.

Repeatability 0.09 (Xe.59) 0.06 (X°.e.) 0.04 (X°.s6) 0.04 (X°,56) 0.003 (X°.5~) 0.05 (XTM) 0.003 (X°-6t) 0.08 (X°.56) 0.08 (X°.56) 0.05 (X°.s') 0.04 (X°.6') 0.06 (X°.61) 0.05 (X°.m) 0.02 (X 1,26)

where X is the mean mass percent of the component. 5 Supporting data available from ASTM Headquarters. Request D02-1296.

737

~

D 4815

15.1.2 Reproducibifity.--The difference between two single and independent results obtained by different operators working in different laboratories on identical material would, in the long run, exceed the following values in Table 4 only in one case in twenty.

SRM

Reproducibility Estimates in Oxygenates in Gasolines Component Reproducibility Methanol (MeOH) Ethanol (EtOH) Isopropanol (iPA) ten-Butanol (tBA) n-Propanol (nPA) MTBE

scc-eutanol(sBA)

DIPE Isobutanol(igA)

ETBE

tert-Pentanol (tAA) n-Butanol (nBA) TAME Total Oxygen

Technology (NIST) provides selected alcohols in reference fuels. As an example the following standard reference materials (SRM) in reference fuels are available as described in the NIST Standard Reference Catalog.6

1829 1837 1838 1839

0.37 (Xo-e•) 0.23 (X°.sT) 0.42 (X°.e~) 0.19 (X°.~7)

Type Alcohols in Reference Fuel Methanol and ten-butanol Ethanol Methanol

Nominal Concentration, Mass % of MeOH EtOH MeOH +"tBuOH 0.335 11.39 10.33 + 6.63 10.33 + 6.63 11.39 0.335

0. I 1 (Xo.s')

16. Keywords

0"44(x°''')

16.1 alcohols; ethers; oxygenates; gasoline; gas chromatography; MTBE (Methyl tert-butylether); ETBE (Ethyl tert-butylether); TAME (Tert-amylmethylether); DIPE (Disopropylether)

0.12 (X°'6~)

0.42 (X °'6~) 0.42(XO.eT)

0.36(x o . , 6 )

0.15 (X°.~) 0.22 (x o-,,) 0.31 (X°'sl) 0.09 (X t.2~)

where X is the mean mass percent of the component. 15.2 Bias--The National Institutes o f Standards and

6NIST Special Publication 260; NIST Standard Reference Materials

1990-1991.

The American Society for Testingand Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the valldtty of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any hme by the responsible technical committee and must be reviewed every hve years and if not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 100 Barr Herbor Drive, West Conshohocken, PA 19428.

738

( ~ l ~ Designation:D 4864-90 (Reapproved 1995)el

An American National Standard

Standard Test Method for Determination of Traces of Methanol in Propylene Concentrates by Gas Chromatography 1 This standard is issued under the fixed designation D 4864; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (e) indicates an editorial change since the last revision or reapproval.

This test method has been approvedfor use by agencies of the Department of Defense. Consult the DoD Index of Spec~qcations and Standards for the specific year of issue which has been adopted by the Department of Defense. ~ NOTe--Section 15 was added editorially in October 1995.

1. Scope 1.1 This test method covers the determination of methanol in propylene concentrates in the range of approximately 4 to 40 mg/kg (parts-per-million by weight). 1.2 The values stated in acceptable SI units are to be regarded as the standard.

methanol phase is withdrawn. A reproducible volume of the extract is then injected into a gas chromatograph (GC) equipped with either a thermal conductivity or a flame ionization detector. The methanol concentration is calculated from the area of the methanol peak using calibration and extraction factors obtained from synthetic blends of known methanol content.

NOTE l - - T h e r e is no direct acceptable SI equivalent for screw threads.

5. Significance and Use 5. I Methanol is a common impurity in propylene. It can have a deleterious effect on various processes that use propylene as a feedstock.

1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Specific hazard

6. Interferences 6.1 There are no known interferences using the GC columns referenced in this test method. However, any water-soluble component that co-elutes with methanol on any other GC column used would interfere.

statements are given in 10.1, Note 5, Note 8, and Note 11.

2. Referenced Documents

2.1 A S T M Standards: D 4307 Practice for Preparation of Liquid Blends for Use as Analytical Standards 2 E 260 Practice for Packed Column Gas Chromatography3

7. Apparatus 7.1 Gas Chromatograph--Any GC equipped with either flame ionization or thermal conductivity detectors with an overall sensitivity sufficient to detect at least 4 mg/kg of methanol. 7.2 Column--Any GC column that separates methanol from water, other alcohols, and any co-extracted hydrocarbons.

3. Terminology 3.1 Definition: 3.1.1 propylene concentrate--concentrate containing more than 90 % propylene. 3.2 Description of Term Specific to This Standard." 3.2.1 outage tube--a length of 6.35-mm (1/4 in.) outside diameter SS tubing normally attached to the inside end of a valve used on a pressure sampling cylinder. It is used to facilitate removal of a set quantity of liquified sample to prevent overpressuring the cylinder.

NOTE 2 - - S e e Table 1 for a suitable list o f c o l u m n s and Figs. 1 a n d 2 for examples o f chromatograms. Also, refer to Practice E 260 for typical instructions in preparing such c o l u m n s . Alternatively, c o l u m n s can be purchased from commercial sources.

7.3 Data Handling SystemmAny commercially available GC integrator or GC computer system capable of accurately integrating the area of the methanol peak is satisfactory. 7.4 Recorder--A strip-chart recorder with a full scale response of 2 s or less and a maximum noise rate of plus or minus 0.3 % full scale. 7.5 Sample Cylinders, 300-mL capacity, stainless steel, Type DOT 3E (12409 kPa (( 1800 psig)) working pressure). 7.6 Balances--Any types capable of weighing a 300-mL sample cylinder and contents accurately to 0.1 g and a 25-mL volumetric flask and contents accurately to 0.0001 g. 7.7 Plug Valve, 1/4-in. male NPT or optionally, 1/4-in. male NPT to 6.35 mm outside diameter (I/4 in.) tubing. (See Note

4. Summary of Test Method 4.1 A known weight of water is pressured into a sample cylinder containing a known amount of liquified propylene. The contents in the cylinder are shaken and the water/ This test method is under the jurisdiction of ASTM Committee 13-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.D0.03 on (74 Test Methods. Current edition approved Sept. 28, 1990. Published December 1990. Originally published as D 4864 - 88. Last previous edition D 4864 - 88. 2 Annual Book of ASTM Standards, Vol 05.02. 3 Annual Book ofASTMStandards, Vol 14.02.

3.) 739

~

D 4864

TABLE 1 Suitable Gas Chromatographic Columns and Temperatures~ Column Number

Column Size, m × mm

1

1.22 x 6.35 OD

SS

2 3

3.05 x 4.76 OD 3.05 x 6.35 OD

SS Cu

4

6.10 x 6.35 OD

Cu

5

1.83 x 2 IO

glass

6

15 x 0.53 ID

fused silica

Tubing Type

Packing

Coating, pm Thickness

15 ~ Carowax 1540 on 60/80 Chromosorb W AW 80/100 mesh Porepak QS 10 ~o Carbowax 1540 on 30/60 mesh Chromosorb T 10 % Carbowax 1540 on 30•60 mesh Chromosorb T 10 "I, Carbowax 20 M on 80/100 Chromosort) W AW ...

Oven Temperature,

°C

...

90

... ...

100 120

...

120

...

70

J&W DB-5, 1.5

70 to 120 at 2*/min

A These six columns have been tested cooperatively and have been found suitable for use with this test method.

PEAK IDENTIFICATION

PEAK mlarflqCAlrlON A UNKNOWN (PROBABLY PROPYLENE)

A

METHANOL

B

PROPYLENE

B METHANOL C WA'FEP

i

k' 'JS

I

NOTE--Column used: No. 4 of Table 1; detector: thermal conductivity.

FIG. 2 Chromatogramof Water/Methanol/Propylene Extract

nut, 6.35 mm outside diameter (1/4 in.). (See Note 3.) 7.13 Septum, TFE-fluorocarbon lined, I l-mm diameter. 7.14 Syringes, l0 and 25 pL.

8. Reagents and Materials 8.1 Methanol, reagent grade or better. 8.2 Propylene, 92+ % purity containing <0.2 mg/kg (ppmw) methanol. 9. Preparation of Apparatus 9.1 Prepare a water injection device. A suitable device is shown in Fig. 3. However, any other device that will deliver from 8 to 15 g of water can be used. 9.2 Prepare a 300-mL sample cylinder for use as a methanol cylinder, as shown in Fig. 4. (This cylinder must not contain an outage tube.) Drill a 3 to 4 mm (approximately I/s in.) hole in a V4-in. NPT brass cap, insert an 1 l-mm septum into it, and screw it onto the plug valve. NOTE 3~AS an alternative, the cylinder can be equipped with 1/4-in. male NPT to a 6.35-mm ('/4-in.) outside diameter tubing plug valve. Then a 6.35-mm tube fitting nut can be used with the septum, thus avoiding the necessityof drilling a brass cap.

RoT. t

HINUTES NOTE--Column used: No. 5 of Table 1; detector: flame ionization.

FIG. 1 Chromatogramsof Water/Methanol Standard and Water/Methanol/Propylene Extract~

7.8 Shut-off Valves, 'A-in. male NPT to 6.35 mm outside diameter ('/4 in.) tubing. 7.9 Regulating Valves, I/4-in. male NPT and 1/4-in. male NPT to I/4-in. female NPT. 7.10 HexNipple, SS, I/4-in. male NPT by 102 m m (4 in.) long. 7.11 llex Coupling, SS, I/4-in. female NPT by 30 mm ( 1.2 in.) long.

9.3 Set up the chromatograph in accordance with the manufacturer's recommendations. Install the analytical column and adjust the gas flows and temperatures so that methanol will elute at the desired time. Condition the column at operating conditions until a stable baseline is

7.12 Brass Cap, I/4-in. NPT or optionally, a tube fitting 740

~) D 4864 TO VACUUM

.

REGULATING VALVE 1/4" MALE NPT

•

TO HIGH PRESSURE --~INERT GAS SOURCE 1723 kPo (250 PSIG)

_S.S. HEX NIPPLE

1/4" NPT X 102ram (4") METHANOL CYLINDER

PLUG VALVE I / 4 " MALE NPT

BRASS CAP WITH SEPTUM

(~) Water injection device FIG. 4

(~) 6.35 mm OD (,/(In.) SS tubing @ Sample cylinder containing propylene O

& ( ~ Shut Off valves, % in. male NPT tO 6.35 mm OD ('/(in.) tubing & @ Regulating valves, 1/( in. male NPT to 1/4 in. female NPT

G&

O

Regulating valves, 1/4 in. male NPT to 1/4 in. male NPT FIG. 3

Water Injection Assembly

recorded at the required sensitivity.

Methanol Cylinder Extraction Factor Determination

volumes of about 10 g, and methanol concentrations in the propylene of 4 to 40 mg/kg.

l l.l.l Methanol Stock Solution--Weigh an empty volumetric flask of at least 25 m L capacity to the nearest 0.0001 g. Add 20 mL of deionized water to the flask and reweigh. Finally, add 2 mL of methanol and again reweigh. Stopper and mix thoroughly. This should contain approximately 73 000 mg/kg (ppm by weight) of methanol. Calculate the exact concentration from the actual weights used.

10. Sampling 10.1 The propylene sample shall be in the liquified state and be representative of the material in the storage tank or process line. Also, for purposes of this method as well as for safety considerations, there must be a vapor space of about 15 % in the sampling container. It is recommended that sampling cylinders of the type listed in Section 7 be used. They can be equipped with an outage tube to effect the 15 % vapor space requirement.

NoTe 5: Warning--Methanol is toxic and flammable. Use with adequate ventilation and keep away from ignition sources. NOTE 6mRefer to Practice D 4307 for additional information in preparing this solution and the calibration solution in I I. 1.2. 1 l.l.2 Methanol Calibration Solutions--In similar manner, make serial dilutions by weight until two different concentrations in the range from 40 to 400 mg/kg are prepared. 1 1.1.3 With the GC at the proper operating conditions, inject an appropriate quantity of each calibration solution, in duplicate, and obtain the area of the methanol peak.

11. Calibration

11.1 Determination of Methanol Response FactormPre-

NOTe 7raThe quantity of solution to be injected will depend largely on the type of detector in use. It varies from about 3 laL for FIDs to 25 ttL for TCDs.

pare several aqueous solutions of methanol in the same concentration range as expected for samples to be analyzed.

11.1.4 For each solution, calculate the response factor for methanol as follows:

NOTE 4--This should be approximately 40 to 400 mglkg (ppmw) on

the basis of propylene sample sizes of 100 to 120 g, water extract 741

(@) O 4864 F = c/u

(l)

where: F = methanol response factor, C = concentration of methanol, mg/kg, in the blend, and H --- area of the methanol peak (average of duplicate injections). 11.1.5 When the response factors at the two concentrations agree within 5 %, average them for use in the final calculation given in Section 13. 11.2 Determination of Methanol Extraction Factorw Since the methanol is not extracted quantitatively due to solubility competition between the water and the propylene, the extraction efficiency must be determined experimentally as follows. 11.2.1 Collect 100 to 120 g (190 to 230 mL) of methanolfree propylene in a tared 300-mL sample cylinder. Reweigh the cylinder to ensure that it contains the proper amount.

OUTAGE TUBE

(OPTIONAL)

II

PROPYLENE CYLINDER

NOTE 8--Liquifled propylene is at high pressure, can cause frostbite, and is flammable. Use appropriate care in handling.

l 1.2.2 As shown in Fig. 4, attach the opposite end of the septum equipped methanol cylinder to a vacuum source. Be sure that this assembly is leak-free. I i.2.3 Open both valves and evacuate the cylinder up to the septum. Then close the plug valve (next to the septum) and continue the evacuation. Finally, close the other cylinder valve, disconnect the cylinder from the vacuum source, and weigh it to the nearest 0. l g. 11.2.4 Flush a l0 or 25-p.L syringe several times with methanol, then fill it to the desired volume (see Table 2), wipe offthe tip, pull the plunger back about l txL, and weigh it to the nearest 0.0001 g. 11.2.5 Open the cylinder plug valve at the septum and immediately inject the methanol in the syringe through the septum into the cylinder. Close the valve and immediately reweigh the syringe to determine the amount of methanol injected. The difference between this weight and that obtained in I 1.2.4 is the weight of methanol injected, W~. 11,2.6 Cool the evacuated cylinder to about 20"C below the temperature of the propylene cylinder. 11.2.7 As shown in Fig. 5, connect the cylinder containing propylene to the evacuated cylinder containing methanol via a hex coupling, a short length of 6.35-mm (V4-in.) outside diameter SS tubing, or any other suitable fitting. Before tightening, flush the connector with a small amount of propylene by briefly opening the lower valve on the propylene cylinder. I 1.2.8 With both cylinders in a vertical position and the propylene cylinder on top, open the valves between them (propylene cylinder first) and allow the liquified propylene to flow into the evacuated cylinder. 11.2.9 Close the valves, disconnect the cylinders, and allow the lower cylinder to warm to room temperature. Wipe TABLE 2

Methanol Injection Sizes

Methanol Volume, p.L

Weight, mg

Equivalent Concentration, mg/kg for 1O0 g propylene

5 10 15

4 8 12

36 72 108

20

16

144

CONNECTOR

METHANOL CYLINDER

FIG. 5

Cylinders Assembly Extraction Factor Determination

off any water condensation and allow to dry. 11.2.10 Weigh the cylinder containing the methanol and propylene blend to the nearest 0.1 g. The difference between this weight and that obtained in 11.2.3 is the weight of methanol and propylene, W2. Calculate the concentration of methanol as follows: C = (W~ x 106)/W~ where: C = concentration of methanol, mggkg, W~ = weight of methanol injected, g, and W2 = weight of propylene plus methanol, g.

742

(2)

~

V 4864 inject the appropriate size of the aqueous extract for the GC and calibration being used. 12.13 Safely vent off the remaining propylene in the sample cylinder and reweigh it to 0. l g (unless the cylinder was already tared.) The difference between this weight and that in 12. l is the weight of the propylene extracted, G.

11.2.11 Shake the cylinder vigorously to mix the propylene and methanol. Then extract the methanol and analyze the extract as described in 12.2 through 12.13. Analyze the extract in duplicate and average the methanol peak areas. 11.2.12 Calculate the methanol content of the extract as described in 13.1, but exclude Fx, the methanol extraction factor. 11.2.13 Calculate the methanol extraction factor as follows: Fx

= C/D

13. Calculation 13.1 Calculate the methanol content of the propylene using the following equation:

(3)

M e t h a n o l , m s / k s ( p p m wt) = (A . F . F x. W ) / G

(4)

where: Fx ffi methanol extraction factor, C = methanol concentration calculated in Eq 2, and D ffi methanol concentration calculated in 11.2.1 I. NOTE 9--It is recommended that the extraction procedure be repeated at a different concentration to verify the accuracy of the factor. Extraction factors of 1 to 2 are typical.

where: A = area of methanol peak, F = methanol response factor for the sample size used (Eq I), Fx = methanol extraction factor (Eq 3), I4," = weight of water used in the extraction, g, and G = weight of propylene extracted, g.

12. Procedure 12.1 Weigh the sampling cylinder containing at least 100 grams of propylene to the nearest 0.1 g. NOtE 10---When practical, it is advisable to weigh the sampling cylinder before sampling to obtain a tare weight.

14. Precision and Bias 4 14.1 Precision--The precision of this test method as determined by the statistical examination of interlaboratory test results is as follows: 14.1.1 Repeatability---The difference between successive results by the same operator with the same apparatus under constant operating conditions on identical test material would, in the long run, in the normal and correct operation of the test method exceed the following value only in one case in twenty: Repeatability -- The maximum allowable ratio of the larger to the smaller result is 2.4. 14.1.2 Reproducibility--The difference between two single and independent results obtained by different operators working in different laboratories on identical test material would, in the long run, exceed the following values only in one case in twenty: Reproducibility = The maximum allowable ratio of the larger to the smaller is 8.0.

12.2 Pressure deionized water into the injection device in a vertical position from the bottom and close the valves. 12.3 As shown in Fig. 3, connect the injection device to the sample cylinder using a hex coupling or other suitable device. 12.4 Attach the other end to an inert gas source at 1724 kPa (250 psig) and purge the lines between V: and V 5. 12.5 Close V 5 and tighten the connection at V 2. 12.6 Pressure the water into the cylinder by opening Valves Vj, V 2, V 3, and V4, in that order. 12.7 Close valves Vj and V4 and depressure the device via V 5. Then disconnect the cylinder. 12.8 Remove any residual water from the outlet of V4 and reweigh the cylinder to 0.1 g. The difference between this weight and that in 12.1 is the weight of the water, IV. 12.9 Shake the cylinder vigorously for at least I0 min. 12.10 Clamp the cylinder in a vertical position and allow the aqueous phase to settle. (When the cylinder contains an outage tube, it must be at the top of the cylinder.) 12.11 Carefully open the bottom valve and drain the aqueous phase containing the methanol into an appropriate container (vial or flask) and cap it.

14.2 Bias--Since there is no accepted reference material suitable for determining the bias for this procedure for measuring methanol, the bias is not available for this test method. 15. Keywords 15.1 gas chromatography; methanol; propylene

NOTE l I: Warning--As soon as the aqueous phase drains, highpressure liquified propylene will surge out.

4 The values in the statements were determined in a cooperative program following RR: D02-1007. The data of the program are fded at ASTM Headquarters. Request RR: D02-1243.

12.12 With the GC at the proper operating conditions,

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and ff not revised, either respproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards end should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend, ff you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 100 Barr Harbor Drive, West Conshohocken, PA 19428.

743

(~l~) Designation: D 4888-88 (Reapproved 1993)° Standard Test Method for Water Vapor in Natural Gas Using Length-of-Stain Detector Tubes 1 This standard is issued under the fixed designation D 4888; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (e) indicates an editorial change since the last revision or reapproval. ~' NoTE--Keywords were added editorially in March 1993.

1. Scope 1.1 This test method covers a procedure for rapid and simple field determination of water vapor in natural gas pipelines. Available detector tubes provide a total measuring range of 0.1 to 40 mg/L, although the majority of applications will be on the lower end of this range (that is, under 0.5 mg/L). At least one manufacturer provides tubes that read directly in pounds of water per million cubic feet of gas. See Note 1. 1.2 Detector tubes are usually subject to interferences from gases and vapors other than the target substance. Such interferences may vary among brands due to the use of different detection methods. Consult manufacturer's instructions for specific interference information. Alcohols and glycols will cause interferences on some water vapor tubes due to the presence of the hydroxyl group on those molecules. 1.3 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 2. Summary of Test Method 2.1 The sample is passed through a detector tube filled with a specially prepared chemical. Any water vapor present in the sample reacts with the chemical to produce a color change, or stain. The length of the stain produced in the detector tube, when exposed to a measured volume of sample, is directly proportional to the amount of water vapor present in the sample. A hand-operated piston or bellowstype pump is used to draw a measured volume of sample through the tube at a controlled rate of flow. The length of stain produced is converted to milligrams per litre of H20 by comparison to a calibration scale supplied by the manufacturer for each box of detection tubes. The system is direct reading, easily portable, and completely suited to making rapid spot checks for water vapor under field conditions. NOTE I--Detector tubes are availablewith calibrationscalesprinted in pounds of water per million cubic feet of gas (Ib/MMCF). The conversion factor is 1 mg/L = 62.3 Ib/MMCF (7 Ib/MMCF = 0.11 rag/L). ' This test method is under the jurisdiction of Committee D-3 on Gaseous Fuels and is the direct responsibility of Subcommittee D03.05 Determination of Special Constituents of Gaseous Fuels. Current edition approved Dec. 30, 1988. Published February 1989.

744

3. Significance and Use 3.1 The measurement of water vapor in natural gas is important due to the gas quality specifications, the corrosive nature of water vapor on pipeline materials, and the effects of water vapor on utilization equipment. 3.2 This test method provides inexpensive field screening of water vapor. The system design is such that it may be used by nontechnical personnel, with a minimum of proper training. 4. Apparatus 4.1 Length-of-Stain Detector Tubes--A sealed glass tube with the breakoff tips sized to fit the tube holder of the pump. The reagent layer inside the tube, typically a silica gel substrate coated with the active chemical, must be specific for water vapor and produce a distinct color change when exposed to a sample of gas containing water vapor. Any substances known to interfere must be listed in the instructions accompanying the tubes. A calibration scale should be marked directly on the tube; however other markings which provide for ready interpretation of water vapor content from a separate calibration scale supplied with the tubes shall be acceptable. The calibration scale shall correlate water vapor concentration to the length of the color stain. Shelf life of the detector tubes must be a minimum of 2 years from date of manufacture, when stored according to manufacturers' recommendations. 4.2 Detector Tube Pump--A hand-operated pump of a piston or bellows type. It must be capable of drawing 100 mL per stroke of sample through the detector tube with a volume tolerance of +5 mL. 2 It must be specifically designed for use with detector tubes. NOTE 2 - - A detector tube and pump together form a unit and must be used as such. Each manufacturer calibrates detector tubes to match the flow characteristics o f its specific pump. Crossing brands o f pumps and tubes is not permitted, as considerable loss o f system accuracy is likely to occur?

4.3 Gas Sampling Chamber--Any container which provides for access of the detector tube into a uniform flow of sample gas at atmospheric pressure, and isolates the sample from the surrounding atmosphere. A stainless steel needle valve (or pressure regulator) is placed between the source valve and the sampling chamber for the purpose of throttling 2 Direct Reading Colorimetric Indicator Tubes Manual, First Ed., American

Industrial Hygiene Associatioh, Akron, OH 44311 (1976).

(~

D 4888 least 10 min if a polyethylene bottle is used. 5.4 Before each series of measurements, test the pump for leaks by operating it with an unbroken tube in place. Consult manufacturers' instructions for leak check procedure details and for maintenance instruction if leaks are detected. The leak check typically takes 1 min. 5.5 Select the tube range that best encompasses water vapor concentration. Reading accuracy is improved when the stain length extends into the upper half of the calibration scale. Consult manufacturer guidelines for using multiple strokes to achieve a lower range on a given tube. 5.6 Break off the tube tips and insert the tube into the pump, observing the flow direction indication on the tube. Place the detector tube into the sampling chamber through the access hole, such that the tube inlet is near the chamber center (Fig. 1).

the sample flow. Flow rate should approximate one to two volume changes per minute, or, at minimum, provide exit gas flow throughout the detector tube sampling period. NOTE 3--A suitable chamber may be devised from a polyethylene wash bottle of nominal 500-mL (16-oz) or I-L (32-oz) size. The wash bottle's internal delivery tube provides for delivery of sample gas to the bottom of the bottle. A V2-in.hole cut in the bottle's cap provides access for the detector tube and vent for the purge gas (Fig. 1). 5. Procedure

5.1 Select a sampling point that will provide access to a representative sample of the gas to he tested (source valve on the main line). The sample point should be on top of the pipeline and equipped with a stainless steel sample probe extending to the middle third of the pipeline. Open the source valve momentarily to clear the valve and connecting nipple of foreign materials. 5.2 Install needle valve (or pressure regulator) at the source valve outlet. Connect sampling chamber using the shortest length of tubing possible (Fig. l). Many flexible tubing materials will be suitable for water vapor sampling, however, if the sampler is also used for other constituents such as hydrogen sulfide, then tubing materials should be chosen carefully. Avoid using tubing which reacts with or absorbs hydrogen sulfide, such as copper or natural rubber. Use materials such as TFE-fluorocarbon, polyethylene, or stainless steel. Stainless steel tubing is preferred. Warning-Exiting gases are highly flammable and may contain toxic levels of hydrogen sulfide. Consider venting the exit gases away from the user when possible. 5.3 Open source valve. Open needle valve enough to obtain positive flow of gas chamber, in accordance with 2.3. Purge the container for at least 3 min (Fig. l). Purge for at

NOTE 4--Detector tubes have temperature limits of 0 to 40"C (32 to 104*F),and sample gases must remain in that range throughout the test. Cooling probes are available for sample temperatures exceeding40"C. 5.7 Operate the pump to draw the measured sample volume through the detector tube. Observe tube instructions when applying multiple strokes. Ensure that a positive flow is maintained throughout the sample duration at the sampling chamber gas exit vent. Observe tube instructions for proper sampling time per pump stroke. The tube inlet must remain in position inside the sampling chamber until the sample is completed. Many detector tube pumps will have stroke finish indicators that eliminate the need to time the sample. NOTE 5--It is very important to ensure that ambient air is not being drawn into the sample. Ambient humidity is often much higher than the water vapor level in the gas sample, and intrusion could bias the reading's high (for example, at 60*F and 10 % relative humidity air contains about 83 lb H20/MMCF or about 1.33 mg/L). 5.8 Remove the tube from the pump and immediately read the water vapor concentration from the tube's calibration scale, or from the charts provided in the box of tubes. Read the tube at the maximum point of the stain. If "channeling" has occurred (nonuniform stain length), read the maximum and minimum stain lengths and average the two. Consult tube instructions for any special information in the event of multicolored stains.

CO.,ROL

SOURCEVALVE~ 1

NOTE 6--If the calibration scale is not printed directly on the detector tube, be sure that any separate calibration chart is the proper match for the tube in use.

SUITABLETUBING~

~ f

PUMP

I ^ I~

~

TUBEACCESB & GASVENT

GASSAMPLING CHAMBER I!~

[I

I ~ DETECTOR

J

TUBE

5.9 If the number of strokes used differs from the number of strokes specified for the calibration scale, correct the reading for water vapor concentration (WVC) as shown below (see also 5.5): specified strokes WVC (corrected) = WVC (reading) x actual strokes 5.10 Record the reading immediately, along with the gas temperature and the barometric pressure. Observe any temperature corrections supplied in the tube instructions. Altitude corrections become significant at elevations above 2000 ft. Correct for barometric pressure, as shown below: 760 mm Hg WVC (corrected) -- WVC (reading) barometric pressure, mm Hg NOTE 7--Even though the amount of chemicals contained in detector tubes is very small, the tubes should not be disposed of carelessly.

FIG. 1 Pumpand Tube Apparatus 745

i1~) D 4888 A general disposal method includes soaking the opened tubes in water prior to tube disposal. The water should be treated to a neutral pH prior to its disposal.

6. Precision and Bias 6.1 The accuracy of detector tube systems is generally considered to be +25 %. This is based mainly on programs conducted by the National Institute of Occupational Safety and Health (NIOSH) in certifying detector tubes for low level contaminants in air, adapted to worker exposure monitoring? NIOSH tested tubes at V2, 1, 2, and 5 times the Threshold Limit Value (TLV), requiring 4-25 % accuracy at the three higher levels, and -+35 % at the 1/2 TLV level (for

example, H2S with a TLV level of 10 ppm was tested at levels of 5, 10, 20, and 50 ppm). The higher tolerance allowed at the low level was due to the loss accuracy for shorter stain lengths. 3 NIOSH discontinued this program in 1983, and it was picked up by the Safety Equipment Institute (SEI) in 1986. 7. Keywords 7.1 gaseous fuels; natural gas 3 "NIOSH Certification Requirements for Gas Detector Tube Units," NIOSH/ TC/A-012, July 1978.

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical dommittee and must be reviewed every five years and if not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee o n Standards, 1916 Race St., Philadelphia, PA 19103.

746

Designation: D 4927 - 96

An American National Standard

Standard Test Methods for Elemental Analysis of Lubricant and Additive Components--Barium, Calcium, Phosphorus, Sulfur, and Zinc by Wavelength-Dispersive X-Ray Fluorescence Spectroscopy 1 This standard is issued under the fixed designation D 4927; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (0 indicates an editorial change since the last revision or reapproval.

1. Scope 1.1 These test methods cover the determination of barium, calcium, phosphorus, sulfur, and zinc in unused lubricating oils at element concentration ranges from 0.03 to 1.0 mass % (0.01 to 2.0 mass % for sulfur). The range can be extended to higher concentrations by dilution of sample specimens. Additives can also be determined after dilution. Two different methods are presented in these test methods. 1.2 Test Method A (Internal Standard Procedure)~Internal standards are used to compensate for interelement effects of X-ray excitation and fluorescence (see Sections 1 to 11, and 16). 1.3 Test Method B (Mathematical Correction Procedure)~The measured X-ray fluorescence intensity for a given element is mathematically corrected for potential interference from other elements present in the sample (see Sections 1 to 6, and 12 to 16). 1.4 The preferred concentration units are mass percent barium, calcium, phosphorus, sulfur, or zinc. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

2. Summary of the Test Methods 2.1 A sample specimen is placed in the X-ray beam and the intensity of the appropriate fluorescence lines of barium, calcium, phosphorus, sulfur, and zinc are measured. Instrument response factors related to the concentration of standards enable the determination of the concentration of elements in the tested sample specimens. Enhancement or depression of the X-ray fluorescence of a given element by an interfering element in the sample may occur. Two test methods (A and B) are described for compensating any interference effect. 2.2 Test Method A (Internal Standard Procedure)--Internal standards are used with the standards and sample specimens to compensate for the potential interelement effects. 2.2.1 Barium, Calcium, Phosphorus, and Zinc~A sample specimen that has been blended with a single internal

standard solution (containing tin or titanium for barium and calcium, zirconium for phosphorus, and nickel for zinc) is poured into an X-ray cell. Total net counts (peak intensity-background) for each element and its respective internal standard are collected at their appropriate wavelengths. The ratios between elemental and internal standard counts are calculated and converted into barium, calcium, phosphorus, or zinc concentrations, or a combination thereof, from calibration curves. 2.2.2 Sulfur--A sample specimen is mixed with a lead internal standard solution and analyzed as described in 2.2. I. 2.3 Test Method B (Mathematical Correction Procedure)--The measured intensity for a given element is mathematically corrected for the interference from other elements in the sample specimen. This requires that intensities from all elements in the specimen be obtained. 2.3.1 The sample specimen is placed in the X-ray beam and the intensities of the fluorescence lines of barium, calcium, phosphorus, sulfur, and zinc are measured. A similar measurement is made away from the fluorescence lines in order to obtain a background correction. Concentrations of the elements of interest are determined by comparison of net signals against appropriate interelement correction factors developed from responses of calibration standards. 2.3.2 The X-ray fluorescence spectrometer is initially calibrated with a suite of standards in order to determine by regression analysis, interelement correction factors and instrument response factors. 2.3.3 Subsequent calibration is achieved using a smaller number of standards since only the instrument response factors need to be redetermined. One of these standards (or an optional synthetic pellet) can be used to monitor instrumental drift when performing a high volume of analyses. 2.4 Additives and additive packages can be determined after dilution with base oil to place the elemental concentrations in the range described in 1. I.

3. Significance and Use 3.1 Some oils are formulated with organo-metallic additives which act as detergents, antioxidants, antiwear agents, and so forth. Some of these additives contain one or more of these elements: barium, calcium, phosphorus, sulfur, and zinc. These test methods provide a means of determining the concentration of these elements which in turn provides an indication of the additive content of these oils.

These test methods are under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and are the direct responsibility of Subcommittee I)02.03 on Elemental Analysis. Current edition approved April 10, 1996. Published June 1996. Originally published as D 4927 - 89. Last previous edition D 4927 - 93.

747

~

D 4927 TEST M E T H O D A (INTERNAL STANDARD PROCEDURE)

4. Interferences 4.1 The additive elements found in lubricating oils will affect the measured intensities from the elements of interest to a varying degree. In general for lubricating oils, the X-radiation emitted by the element of interest is absorbed by the other elements in the sample matrix. Also, the Xradiation emitted from one element can further excite another element. These effects are significant at concentrations varying from 0.03 mass % due to the heavier elements to 1 mass % for the lighter elements. The measured intensity for a given element can be mathematically corrected for the absorption of the emitted radiation by the other elements present in the sample specimen. Suitable internal standards can also compensate for X-ray inter-element effects. If an element is present at significant concentrations and an interelement correction for that element is not employed, the results can be low due to absorption or high due to enhancement. 5. Apparatus 5.1 X-Ray Spectrometer equipped for so~ X-ray detection of radiation in the range from 1 to 10 A. For optimum sensitivity, the spectrometer is equipped with the following: 5.1.1 X-Ray Generating Tube with chromium, rhodium, or scandium target. Other targets can also be employed. 5.1.2 Helium, purgeable optical path. 5.1.3 Interchangeable Crystals, germanium, lithium fluoride (LIF2oo), graphite, or polyethylene terephthalate (PET), or a combination thereof. Other crystals can also be used. 5.1.4 Pulse-Height Analyzer or other means of energy discrimination. 5.1.5 Detector, flow proportional, or scintillation, or flow proportional and scintillation counter. 5.2 Shaker, Mechanical Stirrer, or Ultrasonic Bath, capable of handling from 30-mL to I-L bottles. 5.3 X-Ray Disposable Plastic Cells, with suitable film window. Suitable films include Mylar2, polypropylene, or polyimid with film thicknesses between 0.25 to 0.35 mil (6.3 to 8.8 Ixm). NOTE 1--Some films contain contamination of the elements of interest (Mylar in particular). The magnitude of the contamination is assessed and the same film batch used throughout the entire analysis.

6. Purity of Reagents 6.1 Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, where such specifications are available. 3 Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination. 2 A registered trademark of E. I. du Pont de Nemours and Co. 3 Reagent Chemicals, American Chemical Society Spec(lications, American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed by the American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.]C, and the United States Pharmacopeia and National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville, MD.

748

7. Reagents and Materials 7.1 Helium for optical path of spectrometer. 7.2 P-IO Ionization Gas, 90 volume % argon and 10 volume % methane for the flow proportional counter. 7.3 Diluent Solvent, a suitable solvent free of metals, sulfur, and phosphorus (for example, kerosine, white oil, or xylenes). 7.4 Internal Standard Materials: 7.4.1 Nickel Octoate, preferably containing 5.0 _+0.1 mass % nickel. If the nickel concentration is higher or lower (minimum concentration that can be used is 2.5 _+ 0. I mass % nickel), the laboratory needs to adjust the amount of sample taken in 8. I. l to yield an equivalent nickel concentration level in the internal standard. Other nickel-containing organic matrices (free of other metals, sulfur, and phosphorus) may be substituted provided the nickel is stable in solution, the concentration is known (_>2.5 _+ 0.1 mass % nickel), and the laboratory can adjust the amount of sample taken in 8. I. I to yield an equivalent nickel concentration level in the internal standard if the nickel concentration does not initially contain 5.0 4- 0. I mass % nickel. NOTE 2--Many X-ray tubes emit copper X rays which increase in intensity with age. This does not present a problem when using copper as an internal standard for zinc providing that frequent calibrations are performed. No problem exists when using nickel as internal for zinc and nickel is the preferred internal standard material.

7.4.2 Titanium 2-Ethylhexoide or Tin Octoate, preferably containing 8.0 4- 0. l mass % titanium or tin. If the titanium or tin concentration is higher or lower (minimum concentration that can be used is 4.0 + 0. l mass % titanium or tin), the laboratory needs to adjust the amount of sample taken in 8. I. l to yield an equivalent titanium or tin concentration level in the internal standard. Other titanium or tin containing organic matrices (free of other metals, sulfur, and phosphorus) may be substituted, provided the titanium or tin is stable in solution, the concentration is known (_>4.0 + 0. l mass % titanium or tin), and the laboratory can adjust the amount of sample taken in 8.l.l to yield an equivalent titanium or tin concentration level in the internal standard if the titanium or tin concentration does not initially contain 8.0 + 0.1 mass % titanium or tin. 7.4.3 Zirconium Octoate, preferably containing 12.0 + 0. l mass % zirconium. If the laboratory uses zirconium octoate with a lower mass % zirconium concentration level, the laboratory needs to evaporate away the petroleum solvent to yield a solution that contains 12.0 + 0.1 mass % zirconium. Other zirconium containing organic matrices (free of other metals, sulfur, and phosphorus) may be substituted, provided the zirconium is stable in solution and the concentration is known and does not exceed 12.0 + 0.1 mass % zirconium. If the zirconium concentration is <12.0 4- 0.I mass %, the laboratory needs to evaporate away the petroleum solvent to yield a solution that contains 12.0 4- 0.1 mass % zirconium. 7.4.4 Lead Naphthenate, containing 24.0 4- 0.1 mass % lead. 7.5 Calibration Standard Materials: NOTe 3 n I n addition to calibration standards identified in 7.5.1 to 7.5.5, single-element or multielement calibration standards may also be prepared from materials similar to the samples being analyzed, provided

~) D 4927 NOTE 4: Warning--Hazardous. Lead naphthenate is toxic and precautions should be taken to avoid inhalation of vapors, ingestion, or skin contact.

the calibration standards to be used have previously been characterized by independent primary (for example, gravimetric or volumetric) analytical techniques to establish the elemental concentration mass % levels.

9. Preparation of Calibration Standards 9.1 Barium, Calcium, Phosphorus, and Zinc: 9.1.1 For concentrations less than 0.1 mass %, prepare standards containing 0.00, 0.01, 0.025, 0.050, 0.075, and 0.10 mass % of each respective element in the diluent solvent. 9.1.2 For concentrations greater than 0.1 mass %, prepare standards containing 0.00, 0.10, 0.25, 0.50, 0.75, and 1.00 mass % of each respective element in the diluent solvent. 9.1.3 Dispense 1.000 + 0.001 g of the zirconium internal standard solution described in 7.4.3 into a 30-mL bottle. Prepare an individual bottle for each of the calibration standards. 9.1.4 Dispense 1.000 _+ 0.001 g of the internal standard solution described in 8.1.1 into a 30-mL bottle. Repeat for all of the calibration-standard bottles. 9.1.5 Add 8.00 + 0.001 g of each standard to a respective bottle containing the internal standards and shake or stir well (minimum of 10 rain) to mix the constituents. 9.2 Sulfur: 9.2.1 Prepare five standards covering the range from 0.00 to 2.00 mass % sulfur in the diluent solvent. 9.2.2 Dispense 1.000 + 0.001 g of lead internal standard into 30-mL bottles (one bottle for each standard). 9.2.3 Add 9.000 + 0.001 g of each standard to each respective bottle containing internal standard. Shake or stir contents for a minimum of 10 min using apparatus defined in 5.2.

7.5.1 Barium 2-Ethylhexoide or Sulfonate, with concentrations >4 mass % barium and certified to better than _0.1 % relative, so that calibration standards can be prepared as stated in 9.1.1 and 9.1.2. 7.5.2 Calcium Octoate or Sulfonate, with concentrations >4 mass % calcium and certified to better than + 0 . 1 % relative, so that calibration standards can be prepared as stated in 9.1.1 and 9.1.2. 7.5.3 Bis(2-Ethylhexyl)Hydrogen Phosphate, 97 % purity (9.62 mass % phosphorus). Other phosphorus containing organic matrices (free of other metals) may be substituted provided the phosphorus is stable in solution and the concentration is __.4 mass % phosphorus and certified to better than :t:0.1% relative, so that calibration standards can be prepared as stated in 9.1.1 and 9.1.2. 7.5.4 Zinc Sulfonate or Octoate, with concentration >4 mass % zinc and certified to better than - 0 . 1 % relative, so that calibration standards can be prepared as stated in 9.1.1 and 9.1.2. 7.5.5 Di-n-Butyl Sulfide, 97 % purity, (21.9 mass % sulfur). Other sulfur containing organic matrices (free of metals) may be substituted, provided the sulfur is stable in solution and the concentration is _>2 mass % sulfur and certified to better than - 0 . 1 % relative, so that calibration standards can be prepared as stated in 9.1.2.

8. Preparation of Internal Standards 8.1 Barium, Calcium, Phosphorus, and Zinc." 8.1.1 Dispense 240 + 0.5 g of nickel octoate (5.0 _+ 0.1 mass % nickel), 30 _+ 0. l g of titanium 2-ethylhexoide (8.0 _+ 0.1 mass % titanium) or 30 + 0.1 g of tin octoate (8.0 + 0.1 mass % tin), and 450 + 1 g of diluent solvent into a I-L bottle. Shake or stir the bottle for a minimum of 10 min. If the laboratory uses internal materials that have different elemental concentrations than those explicitly stated in 7.4.1 and 7.4.2, it will be necessary for the laboratory to adjust the amount of sample taken in order to obtain an equivalent elemental concentration in the internal standard blend that is prepared according to the following equations: A = 240 x (5/x) (1) B = 30 x (8/y) (2) C = 720 - [h + B] (3) where: A -- nickel containing material in blend, g, B = titanium or tin containing material in blend, g, C = diluent to add to blend, g, x = nickel in material chosen as an internal standard, mass %, and y = titanium or tin in material chosen as an internal standard, mass %. 8.2 Sulfur." 8.2.1 Lead Naphthenate (Warning--see Note 4), 24 mass % lead, serves as a suitable internal standard. No further treatment of this compound is necessary.

10. Instrument Calibration for Barium, Calcium, Phosphorus, Sulfur, and Zinc 10.1 Fill respective X-ray cups at least half full with the calibration standard solutions. Make sure that no wrinkles or bulges are present in the film. The film must be fiat. 10.2 Place the sample cups in the X-ray beam in order to TABLE 1 Suggested Parameters for Intemal Standard Method NOTE--These conditions serve as suggestions only. Optimum parameters may differ as a function of instrument, tube target, and crystal used. These conditions are for use with a chromium target and LJFaoocrystal.

Barium Calcium Tin (internal standard for barium) Tin (Intemal standard for calolum) Titanium (altamatlve Internal standard for barium and calcium Phosphorus Zirconium (internal standard for

Line

Wavelength, A

Angle, 2#

L~ K<xI ,= Lvl

2.77596 3.35948 3.00115

87.17 113.09 96.38

Lat

3.5994

126.77

Ka2

2.75216

86.23

K~1.2 L,,~

2.836 2.7958

89.56 87.56

Kal,2 K~,2

1,43644 1.65791

41.80 48.63

Kal, 2

1,54194

45,03

Ka1,2 Me1

2.4746 2.4345

75.85 74.41

phosphorus)

Zinc Nickel (internal standard for zinc) Copper (alternative internal standard for zinc) Sulfur Lead (intemal standard for sulfur)

749

(~) D 4927 measure and record the net intensity (peak intensity-background intensity) for both the analyte signal and the internal standard signal according to the wavelengths and conditions suggested in Table 1. Up to 60-s counting periods may be used at each wavelength position. Do this for each of the calibration standards for each of the elements. NOTE 5--The parameters indicated in Table I are presented for guidance only and they will vary according to the instrument used. 10.3 Calculate the ratio, R, of the net element counts to their corresponding net internal standard counts for all of the net elements and standards as follows:

11.1.4 The mass % of barium, calcium, phosphorus, or zinc, or a combination thereof, is calculated as follows: Element, mass % = M (S + D)

(5)

where: M = concentration of the element from the calibration curve, mass %, S = mass of sample specimen, g, and D = mass of diluent solvent, g.

I 1.2 Determination of Sulfur:

R = El1 (4) where: E --- net element counts, and I --- net internal standard counts. NOTE 6--Many modem X-ray spectrometer instruments will calculate this ratio automatically and store the information in the instrument computer system. 10.4 Perform regression analyses for each calibration element by ratioing the net element counts to the net internal standard counts versus the element concentration (mass %) on linear graph paper or by way of the instrument computer system. It is recommended that two separate regression analyses be performed for each calibration set for barium, calcium, phosphorus, and zinc, as defined in 9. I. 1 and 9.1.2. The regression analyses will determine a slope and intercept for each calibration element that will be used to determine element concentrations of samples to be tested.

11.2.1 If the sulfur content is known to be less than 2 mass %, transfer a 9.000 ± 0.001-g sample specimen into a 30-mL bottle containing 1.000 + 0.001 g of the lead internal standard (8.2. I ). 11.2.2 Iftbe sulfur content is known or found to be higher than 2 mass %, dilute to approximately 1 to 1.5 mass % with the diluent solvent. Transfer 9.000 _+ 0.001 g of the diluted specimen into a 30-mL bottle containing 1.000 ± 0.001 g of lead internal standard (8.2.1). 11.2.3 Run either 11.2.1 or 11.2.2 under the same conditions as the standards. Calculate the sulfur-to-lead ratio and obtain the sulfur concentration from the calibration curve. Undiluted sample results are reported directly. Refer to 11.1.4 for the calculation of diluted samples. TEST METHOD B (MATHEMATICAL CORRECTION PROCEDURE)

12. Reagents and Materials

12.1 Helium for optical path of spectrometer. 12.2 P-IO Ionization Gas, 90 volume % argon and 10

11. Procedure

11.1 Determination of Barium, Calcium, Phosphorus, and Zinc: 11.1.1 If the concentration of the element is known or suspected to be less than 1.0 mass %, dispense 8.000 ± 0.001 g of the sample specimen into a 30-mL bottle containing 1.000 ± 0.01 g of internal standard solution 8.1.1 and 1.000 ± 0.001 of internal standard solution 8.1.2. Mix carefully using shaker for a minimum of 10 rain. 11.1.2 Ifthe concentration is known or found to be higher than 1.0 mass %, then dilute a sample specimen with the diluent solvent, such that the working concentration in the blend is reduced to approximately 0.5 mass %. Dispense 8.000 + 0.001 g of the diluted specimen into a 30-mL bottle containing 1.000 + 0.001 g of internal standard 8.1.1 and 1.000 ± 0.001 g of internal standard 8.1.2. Mix carefully using shaker for a minimum of 10 min. 11.1.3 Pour a portion of sample from either 11.1.1 or I 1.1.2 into a cell as described in 10. I and obtain counts as described in 10.2. Calculate the ratio between the element and its internal standard as described in 10.3. Obtain the concentration of the element from the appropriate calibration curve. Undiluted sample results are to be reported

directly. NOTe 7--In addition to calibration standards identified in 12.4.1 to 12.4.5, single-elementor multielement calibration standards may also be prepared from materials similar to the samples being analyzed, provided the calibration standards to be used have previously been characterized by independent primary (for example, gravimetrie or volumetric) analytical techniques to establish the elemental concentration mass % levels. 750

volume % methane for the flow proportional counter. 12.3 Diluent Solvent, a suitable solvent free of metals, sulfur, and phosphorus (for example, kerosine, white oil, or xylenes). 12.4 Calibration Standard Materials: 3 12.4.1 Barium 2-Ethylhexoide, with concentrations ---5 mass % barium and certified to better than + 0 . 1 % relative, so that calibration standards can be prepared as stated in 13.1. Other barium containing organic matrices (free of other metals, sulfur, and phosphorus) may be used, provided the barium is stable in solution and the concentration is >5 mass % barium and certified to better than ± 0 . 1 % relative. 12.4.2 Calcium Octoate, with concentrations >4 mass % calcium and certified to better than + 0 . 1 % relative, so that calibration standards can be prepared as stated in 13.1. Other calcium containing organic matrices (free of other metals, sulfur, and phosphorus) may be used, provided the calcium is stable in solution and the concentration is _>4 mass % calcium and certified to better than + 0 . 1 % relative. 12.4.3 Bis(2-Ethylhexyl)Hydrogen Phosphate, 97 % purity (9.62 mass % phosphorus). Other phosphorus containing organic matrices (free of other metals and sulfur) may be substituted, provided the phosphorus is stable in solution and the concentration is >__2.5 mass % phosphorus and certified to better than + 0 . 1 % relative, so that calibration standards can be prepared as stated in 13.1. 12.4.4 Zinc Octoate, with concentrations _>2.5 mass % zinc and certified to better than ± 0 . 1 % relative, so that calibration standards can be prepared as stated in 13.1. Other zinc containing organic matrices (free of other metals, sulfur,

lip D 4927 and phosphorus) may be used, provided the zinc is stable in solution, and the concentration is _>2.5 mass % zinc and certified to better than +0.1% relative. 12.4.5 Di-n-Butyl Sulfide, 97 % purity (21.9 mass % sulfur). Other sulfur containing organic matrices (free of metals and phosphorus) may be substituted, provided the sulfur is stable in solution and the concentration is _>7.5 mass % sulfur and certified to better than +0.1% relative, so that calibration standards can be prepared as stated in 13.1.

TABLE 3

Barium

NOTE 8 - - T h e parameters indicated in Table 3 are presented for guidance only and they will vary according to the instrument used.

14.3 Interelement correction factors and the slope and intercept of the calibration line are obtained by the regression analysis using the program supplied with the particular instrument used (if available) or a model similar to the following form:

Recommended Concentrations for Standards for the Mathematical Correction Procedure (All Values in Mass %)

TABLE 2

Beduin

Calcium

Phosphorus

Sulfur

Zinc

0 1.0 1.0 0 0.5 0 1.0 1.0 0 0,5 1.0 1.0 0 0 0.5 1.0 0

0.8O 0 0 0.80 0.40 0 0 0 0.80 0.40 0.80 0.80 0 0.80 0.40 0.80 0

0.5 0 0.5 0.5 0.25 0.5 0 0.5 0 0.25 0 0.5 0.5 0 0.25 0.5 0

0 0 0 1.5 0.75 1.5 1.5 1.5 1.5 0.75 1.5 1.5 0 0 0.75 0 1.5

0

0

0

0

1.0 0.5

0.80 0.40

0 0.25

0 0.75

0.5 0 0.5 0 0.25 0.5 0.5 0 0.5 0.25 0 0.5 0 0 0.25 0 0 0.5 0.5 0.25

Suffur

Zinc

5.37 graphite

1.43 LiF2oo

106.22 108.00

41.79 43.6

F

FS

Peak wavelength, A Analyzing crystal

2.78 UF2oo

3.55 LiF,,oo

Peak angle, 20 Background angle, 20 Detector 'q

87.13 85.7

113.1 114.5

6.15 germanium 140.92 142.90

FS

F

F

15. Procedure 15.1 Fill X-ray cups at least half full with the sample specimens to be analyzed. Make sure that no wrinkles or bulges exist in the film. The film must be flat. 15.2 Obtain intensities for all of the elements for all of the samples in the manner prescribed for the standards (14.2). 15.3 The elemental concentrations for each sample specimen are calculated using the measured intensities combined with the correction factors obtained from the calibration procedure (14.3). 15.4 Procedures 15.1 to 15.3 are repeated on diluted sample specimens in those cases where elemental concentrations exceed l mass % for barium, calcium, phosphorus, or zinc, or 2 mass % for sulfur.

(6)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Phos-

phorus

where: C; = concentration of the analyte Element i, Di = intercept of the calibration curve for Element i, Ei = slope of the calibration curve for Element i, I; = measured net intensity for Element i, a,j = interelement correction factor for effect of Element j on analyte Element i, and Cj = concentration of interfering Element j. slope, intercept, and a set of interelement correction factors are calculated for each analyte. 14.4 The initial calibration to obtain the slope, intercept, and interelement correction factors is performed initially when the test method is set up, after any major maintenance is performed on the instrument that can affect the calibration (for example, new X-ray tube installed, new crystal added, and so forth), and as deemed necessary by the operator (for example, triggered by quality control sample results). Subsequent re-calibration is performed with a minimum of three standards containing each of the calibration elements at nominal concentrations across the respective calibration ranges in order to check the values of the slope and intercept. An optional stable pellet can also be prepared which can be measured on a periodic basis for the purpose of monitoring instrumental drift.

14. Calibration 14.1 Fill respective X-ray cups at least half full with the calibration standard solutions. Make sure that no wrinkles or bulges are present in the fdm. The fdm must be flat. 14.2 Place the sample cups in the X-ray beam in order to measure and record the net intensity (peak intensity-background intensity) for each element and in each calibration standard according to the wavelengths and conditions suggested in Table 3. Up to 60-s counting periods may be used at each wavelength position.

Standard

Calcium

A F = flow proportional detector, S = scintillation detector, and FS = both detectors.

13. Preparation of Calibration Standards 13.1 Prepare calibration standards by precise dilution of each of the elements that meet the requirements of 12.4.1 to 12.4.5, with the diluent solvent for the recommended concentrations prescribed in Table 2. 13.2 Although Table 2 is an abbreviated listing of all the possible combinations of elements and concentration range interactions that can be tested to determine mathematical correction factors for the various elements, the number of standards and the varying degree of element concentrations in the matrix are sufficient.

C, = (Dl + Eft/) (1 + Y.j % Cj)

Suggested Spectrometer Seffings for Mathematical Correction Method

16. Precision and Bias4 16.1 The precision of these test methods as determined by the statistical examination of the interlaboratory test results is as follows: 16.1.1 Repeatability---The difference between successive results obtained by the same operator with the same appa4 Supporting data are available from ASTM Headquarters. Request RR: 1302-1259.

751

~)

D 4927

TABLE 4 PrecisiorP tot internal Standard Method r at 0.1

Element

r

mass~

R

Barium Calcium Phosphorus Sulfur Zinc

0.0304 (x - 0.0111 ) 0.0211 x °-as 0.0455 (x + 0.0435) 0.0444 (x - 0.0052) 0.0204x

0.003 0.005 0.007 0.004 0.002

0.0704 (x - 0.111) 0.0802x°,as 0.0746 (x + 0.0435) 0.2086 (x - 0.0052) 0.0512x

R st 0.1 mass

0.006 0.018 0.011 0.020 0.005

A Where r = repeatability, R = reproducibility, and x = concentration of the element of interest.

TABLE 5

Precision A for Mathematical

Element

r

r at 0.1 mass ~

Barium Calcium Phosphorus Sulfur Zinc

0.020x 1.1a 0.0238x°.a6 0.0348xo,92 0.0509 (x + 0.0214) 0.0193x

0.001 0.003 0.004 0.006 0.002

Correction Method R

R at 0.1 mass

0.138xo,ga 0.1136x° . ~ 0.0642x°.as 0.1559 (x + 0.0214) 0.1165x

0.016 0.016 0.018 0.019 0.012

A Where r = repeatability, R = reproducibility, and x = concentration of the element of interest.

one case in twenty. 16.1.2.1 Test MethodA--Values can be obtained for each element for any given concentration within the scope of this test method by using the expressions listed in Table 4. 16. 1.2.2 Test Method B--Values can be obtained for each element for any given concentration within the scope of this test method by using the expressions listed in Table 5. 16.2 Bias--The bias for these test methods was not determined since no suitable reference materials of known composition were available.

ratus under constant operating conditions on identical test materials would, in the long run, in the normal and correct operation, exceed the following values only in one case in twenty. 16. I. I. l Test Method A--Values can be obtained for each element for any given concentration within the scope of this test method by using the expressions listed in Table 4. 16.1.1.2 Test Method B--Values can be obtained for each element for any given concentration within the scope of this test method by using the expressions listed in Table 5. 16.1.2 Reproducibility--The difference between two single and independent results obtained by different operators working in different laboratories on identical material would, in the long run, exceed the following values only in

17. Keywords 17. l additives; barium; calcium; lubricating oil; phosphorous; sulfur; wavelength-dispersive; X-ray fluorescence; zinc

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision st any time by the responsible technical committee and must be reviewed every five years and ff not revised, either reepproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend, ff you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 100 Barr Harbor Drive, West Conshohoukan, PA 19428.

752

Designation: D 4928 - 96

An Amedcan National Standard

Designation: MPMS Chapter 10.9

lilt D,~otltHI i)1 pI I m l M l l l M

Designation: 386/88

Standard Test Methods for Water in Crude Oils by Coulometric Karl Fischer Titration 1 This standard is issued under the fixed designation D 4928; the number immediately followin8 the designation indicates the year of original adoption or, in the case &revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (e) indicates an editorial change since the last revision or reapproval.

This test method has been approved by the sponsoring committees and accepted by the cooperating societies in accordance with established procedure.

tric end-point detector and the titration is terminated. Based on the stoichiometry of the reaction, one mole of iodine reacts with one mole of water, thus the quantity of water is proportional to the total integrated current according to Faraday's Law. 3.2 The precision of this test method is critically dependent on the effectiveness of the homogenization step. The efficiency of the mixer used to achieve a homogeneous sample is determined by the procedure given in Annex A I. 3.3 An alternative pr2w,edure is provided in Appendix XI for the direct determination of the volume % of water in crude oils. This procedure involves measuring only the volume of crude oil injected into the titration vessel instead of measuring the mass of crude oil injected. The conditions under which the alternative volumetric measurements can be made are listed in the appendix.

1. Scope 1. I This test method covers the determination of water in the range from 0.02 to 5 mass % in crude oils. Mercaptan (RSH) and sulfide (S- and H2S) sulfur are known to interfere with this test method (see Section 5). 1.2 This test method can be used to determine water in the 0.005 to 0.02 mass % range, but the effects of the mercaptan and sulfide interference at these levels has not been determined. 1.3 This test method is intended for use with standard commercially available eoulometric Karl Fischer reagent. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements, see Notes I, 2, and 3.

4. Significance and Use 4.1 A knowledge of the water content of crude oil is important in the refining, purchase, sale, or transfer of crude OtiS.

2. Referenced Documents

2.1 A S T M Standards: D 1193 Specification for Reagent Water 2 D4057 Practice for Manual Sampling of Petroleum and Petroleum Products 3 D 4177 Practice for Automatic Sampling of Petroleum and Petroleum Products 3 E 203 Test Method for Water Using Karl Fischer Reagent4

5. Interferences 5.1 A number of substances and classes of compounds associated with condensation or oxidation-reduction reactions interfere in the determination of water by Karl Fischer. In etude oils, the most common interferences are mereaptans and sulfides. At levels of less than 500 ttg/g (ppm) (as sulfur) the interference from these compounds is insignificant. For more information on substances that interfere in the determination of water by Karl Fischer titration method see Test Method E 203. 5.2 The significance of the mercaptan and sulfide interference on the Karl Fischer titration for water levels in the 0.005 to 0.02 mass % range has not been determined experimentally. At these low water levels, however, the interference can be expected to be significant for mercaptan and sulfide levels of less than 500 ttg/g (ppm) (as sulfur).

3. Summary of Test Method 3.1 After homogenizing the crude oil with a mixer, an aliquot is injected into the titration vessel of a Karl Fischer apparatus in which iodine for the Karl Fischer reaction is generated coulometrically at the anode. When all the water has been titrated, excess iodine is detected by an electromei This test method is under the jurisdiction of ASTM Committee 1)-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.02.0B on Sediment and Water. Current edition approved Dec. 10, 1996. Published February 1997. Originally published as D 4928 - 89. Last previous edition D 4928 - 89. 2 Annual Book of ASTM Standards, Vol 11.01. 3 Annual Book of ASTM Standards, Vo105.02. 4 Annual Book of ASTM Standards, Vol 15.05.

6. Apparatus 6.1 Karl Fischer Apparatus, using electrometric end point. Presently there are available on the market a number of 753

~) D 4928 commercial coulometric Karl Fischer titration assemblies. Instructions for operation of these devices are provided by the manufacturer and not described herein. 6.2 Mixer, to homogenize the crude sample. 6.2.1 Non-Aerating, High-Speed, Shear Mixer--The mixer shall be capable of meeting the homogenization efficiency test described in Annex A I. The sample size is limited to that suggested by the manufacturer for the size of the mixing probe. 6.2.2 Large volume dynamic mixing systems such as those used with automatic crude oil sampling receptacles are acceptable providing they comply with the principles of Annex A 1. 6.3 Syringes: 6.3.1 Samples are most easily added to the titration vessel by means of accurate glass syringes with LUER fittings and hypodermic needles of suitable length. The bores of the needles used should be kept as small as possible, but large enough to avoid problems arising from back pressure and blocking while sampling. Suggested syringe sizes are as follows: 6.3.1.1 Syringe, lO ttL with a needle long enough to dip below the surface of the anode solution in the cell when inserted through the inlet port septum. This syringe is used in the calibration step (Section 9). It should be of suitable graduations for readings to the nearest 0.01 I~L or better. 6.3.1.2 Syringes, 250 ttL, 500 ttL and 1 mL, for crude oil samples. For the volumetric determination procedure, the syringes should be accurate to 1 I~L, 1 IxL and 0.01 mL respectively. 7. Reagents and Materials

7.1 Purity of Reagents--Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, where such specifications are available. 5 Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination. 7.2 Purity of Water--Unless otherwise indicated, references to water shall be understood to mean reagent water as defined by Type IV of Specification D 1193. 7.3 Xylene, reagent grade. Less than 0.05 % water. NOTE 1: Warning--Flammable.Vapor harmful.

7.4 Karl Fischer Reagent--Standard commercially available reagents for coulometric Karl Fischer titrations. 7.4.1 Anode Solution, shall be 6 parts of commercial Karl Fischer anode solution with 4 parts of reagent grade xylene. Fresh Karl Fischer anode solution must be used. Other proportions of anode solution and xylene can be suitably used and should be determined for a particular reagent and apparatus. 5 Reagent Chemicals, American Chemical Society Spec~cations. American Chemical Society, Washington, DC. For suBestions on the testing of reagents not listed by the American Chemical Society, see Analar Standard~ for Laboratory Chemical, BDH Ltd., Poole, Dorset, U.IC, and the United States Pharmacopeia and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.

754

NOTE 2: Warning--Flammable,toxicby inhalationand if swallowed, avoid contact with skin. 7.4.2 Cathode Solution, use standard commercially available Karl Fischer cathode solution. Fresh solution shall be used. NOTE 3: Warning--Flammable,can be fatal if inhaled,swallowed,or absorbed through skin. Possiblecancer baT~rd. 8. Sampling and Test Specimens 8.1 Sampling, is defined as all the steps required to obtain an aliquot representative of the contents of any pipe, tank, or other system, and to place the sample into a container for analysis by a laboratory or test facility. The laboratory sample container and sample volume shall be of sufficient dimensions and volume to allow mixing as described in 8.4. 8.2 Laboratory Sample--The sample of crude oil presented to the laboratory or test facility for analysis by this test method. Only representative samples obtained as specified in Practice D 4057 and Practice D 4177 shall be used to obtain the laboratory sample. NOTE 4---Examples of laboratory samples include sample bottles from manual sampling, receptaclesfrom automaticcrude oil samplers, and storagecontainersholdinga crude oil from a previousanalysis. 8.3 Test Specimen--The sample aliquot obtained from the laboratory sample for analysis by this test method. Once drawn, the entire portion of the test specimen will be used in the analysis. Mix the laboratory sample properly as described in 8.4 prior to drawing the test specimen. 8.4 Mix the laboratory sample of crude oil immediately (within 15 rain) before drawing the test specimen to ensure complete homogeneity. Mix the sample at room temperature (15 to 25"C) or less in the laboratory sample container and record the temperature of the sample in degrees Celsius immediately before mixing. The type of mixer depends on the quantity of crude oil in the laboratory sample container. Before any unknown mixer is used, the specifications for the homogenization test, Annex A l, must be met. Reevaluate the mixer for any changes in the type of crude, volume of crude in the container, the shape of the container, or the mixing conditions (such as mixing speed and time of mixing). 8.5 For small laboratory sample containers and volumes, 50 to 500 mL, a nonaerating, high speed, shear mixer is required. Use the mixing time, mixing speed, and height of the mixer probe above the bottom of the container found to be satisfactory in Annex A l. For larger containers and volumes appropriate mixing conditions shall be defined by following a set of procedures similar to those outlined in Annex A 1 and Method D 4177 but modified for application to the larger containers and volumes. Clean and dry the mixer between samples. 8.6 Record the temperature of the sample in degrees Celsius immediately after homogenization. The rise in temperature between this reading and the initial reading prior to mixing (8.4) is not to exceed 10°C, otherwise loss of water can occur or the emulsion can become unstable. 8.7 Select the test specimen size as indicated in Table l based on the expected water content. 9. Preparation of Apparatus 9.1 Follow the manufacturer's directions for preparation

~) D 4928 TABLE 1

Approximate Test Specimen Size Based on Expected Water Content

Expected Water Content, mass

Sample Size, g

Water Titrated, pg

0.02-0.1 0.1 --0.5 0.5-5.0

1.0 0.5 0.25

200-1000 500-2500 1250-12500

NOTE 6 - - I f the concentration of water in the sample is completely unknown, it is advisable to start with a small trial portion of sample to avoid excessive titration time and depletion of the reagents. Further adjustment of the aliquot size can then be made as necessary.

11.1.2.2 When the background current or titration rate returns to a stable reading at the end of the titration as discussed in 9.5, additional samples can be added in accordance with 1 I. 1.2.1. 11.1.3 Replace the solutions when one of the following occurs and then repeat the preparation of the apparatus as in Section 9. I l.l.3.1 Persistently high and unstable background current. 11.1.3.2 Phase separation in the anode compartment or crude oil coating the electrodes. 11.1.3.3 The total crude content added to the titration vessel exceeds one quarter of the volume of solution in the anode compartment. 11.1.3.4 The solutions in the titration vessel are greater than one week old. 11.1.3.5 The instrument displays error messages which directly or indirectly suggest replacement of the electrodes-see instrument operating manual. 11.1.3.6 The result from a 10-~tL injection of water is outside I0 000 ± 200 ~tg. 11.1.4 Thoroughly clean the anode and cathode compartments with xylene if the vessel becomes contaminated with crude. Never use acetone or similar ketones. Clogging of the frit separating the vessel compartments will also cause instrument malfunction. 11.1.5 For erudes too viscous to draw into a syringe, add the sample to a clean, dry dropper bottle and weigh the bottle and crude. Quickly transfer the required amount of sample to the titration vessel with the dropper. Reweigh the bottle. Titrate the sample as in 11.2. 11.2 Volume Determination of Sample Size: 11.2.1 This procedure is applicable only when conditions warrant, that is, when the vapor pressure and viscosity of the crude permit an accurate determination of the volume of the crude oil. Viscous etudes may prove difficult to accurately measure with a syringe. 11.2.2 The presence of gas bubbles in the syringe can be a source of interference. The tendency of the crude to form gas bubbles is a function of the crude type and corrersponding vapor pressure. Additional care is required in filling the syringe to reduce the formation of gas bubbles. l 1.2.3 The referee procedure for determination of water in crude oil by coulometric Karl Fischer titration is the mass measurement of the crude oil in 11. I. 11.2.4 The basic steps are the same as those for mass determination (see 11.1) with the following exception. With a clean, dry syringe of suitable capacity (see Table l), withdraw at least three portions of sample and discard to waste. Immediately withdraw a further portion of sample, expel any gas in the syringe, clean the needle with a paper tissue and record the volume in the syringe to the nearest 1 or 10 ~tL as appropriate (see 6.3.1.2). Insert the needle through the port inlet septum, start the titration, and with the tip of the needle just below the liquid surface, inject the entire contents of the syringe. After the end point is reached,

and operation of the titration apparatus. 9.2 Seal all joints and connections to the vessel to prevent atmospheric moisture from entering the apparatus. 9.3 Add to the anode (outer) compartment the mixture of xylene and Karl Fischer anode solutions which has been found suitable for the particular reagent and apparatus being used. Add the solutions to the level recommended by the manufacturer. 9.4 Add to the cathode (inner) compartment the Karl Fischer cathode solution to a level 2 to 3 mm below the level of the solution in the anode compartment. 9.5 Turn on the apparatus and start the magnetic stirrer for a smooth stirring action. Allow the residual moisture in the titration vessel to be titrated until the end point is reached. Do not proceed beyond this stage until the background current (or background titration rate) is constant and less than the maximum recommended by the manufacturer of the instrument. NOTE 5--High background current for a prolonged period can be due to moisture on the inside wallsof the titration vessel.Gentle shaking of the vessel(or more vigorousstirring action) will wash the inside with electrolyte. Keep the titrator on to allow stabilization to a low background current. 10. Standardization

10.1 In principle, standardization is not necessary since the water titrated is a direct function of the coulombs of electricity consumed. However, reagent performance deteriorates with use and must be regularly monitored by accurately injecting 10 ~tg of pure water. Suggested intervals are initially with fresh reagent and then after every 10 determinations (see 11.3). If the result is outside 10 000 ± 200 ~tg, replace both the anode and cathode solutions. 11. Procedure

11.1 Mass Determination of Sample Size: 11.1.1 Add fresh solvents to the anode and cathode compartments of the titration vessel and bring the solvent to end-point conditions as described in Section 9. 11.1.2 Add an aliquot of the crude oil test specimen to the ti.tration vessel immediately after the mixing step described in 8.4 using the following method. 11.1.2.1 Starting with a clean, dry syringe of suitable capacity (see Table 1 and Note 6), withdraw at least three portions of the sample and discard to waste. Immediately withdraw a further portion of sample, clean the needle with a paper tissue, and weigh the syringe and contents to the nearest 0.1 rag. Insert the needle through the inlet port septum, start the titration and with the tip of the needle just below the liquid surface, inject the sample. Withdraw the syringe and reweigh the syringe to the nearest 0.1 rag. After the end point is reached, record the titrated water from the digital readout on the instrument. 755

~

D 4928 TABLE 2

record from the digital readout on the instrument the micrograms titrated.

~; Water

12. Calculation 12.1 Calculate the water content of the sample as follows: Water, mass % :

W; 10 O 0 0 x w 2

where: W~ = mass of water titrated, I~g, and W2 = mass of sample used, g. 12.2 Calculate the water content of a volume sample as follows: Water content, v o l u m e % =

WI 1000O X W2

where: W~ = volume of water titrated, ttL (same as the Ixg of water reported by the coulometric titrator), and W2 = volume sample used, mL.

Precision Internals

Repeatability (r)

Reproducibility (R)

(Mass or Volume)

Mass

Volume

Mass

Volume

0.02 0.05 0.1 0.3 0.5 0.7 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0

0.003 0.005 0.01 0.02 0.03 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.10 0.11 0.12

0.034 0.008 0.01 0.03 0.04 0.04 0.06 0.07 0.09 0.10 0.12 0.13 0.14 0,15 0.16

0.008 0.014 0.02 0.05 0.07 0.08 0.11 0.14 0.17 0.19 0.22 0.24 0,26 0.29 0.31

0.008 0.015 0.02 0.05 0.07 0.09 0.11 0.15 0.18 0.21 0.23 0.26 0.28 0.31 0.33

14.1.2 Reproducibility--The difference between two single and independent results obtained by different operators working in different laboratories on identical test material would, in the long run, exceed the following values only in one case in twenty (see Table 2). 14.1.2.1 For a mass sample, R = 0.105 (X2/3) (4)

13. Report 13.1 For a mass sample, report the water content to the nearest 0.01 mass %. 13.2 For a volume sample, report the water content to the nearest 0.01 volume %.

where: X = sample mean from 0.005 to 5 mass %. 14.1.2.2 For a volume sample, R = 0.112 (X2/3)

14. Precision and Bias 14.1 The precision of this test method as determined by the statistical examination of intedaboratory test results is as follows:6 14.1.1 Repeatability--The difference between successive results obtained by the same operator with the same apparatus under constant operating conditions on identical test material would, in the long run, in the normal and correct operation of the test method, exceed the following values only in one case in twenty (see Table 2). 14.1.1.1 For a mass sample, r = 0.040 (X2/3) (2)

(5)

where: X = sample mean from 0.005 to 5 volume %.

where: X = sample mean from 0.005 to 5 volume %. 14.2 Bias 14.2.1 No significant difference was found between the average water content obtained by this test method and the expected water content (based on the amount of added water) for the crude oil samples analyzed in the round robin used to evaluate the precision of this test method.6 14.2.2 The interference from mercaptan sulfur follows the theoretical stoichiometry of 1 to 0.28, that is 1000 mg/g (ppm) of mercaptan sulfur can generate a response equivalent to 280 mg/g (ppm) water by this test method. The interference from H2S sulfur follows the stoichiometry of 1 to 0.56, that is 1000 mg/g (ppm) of hydrogen sulfde sulfur can generate a response equivalent to 560 mg/g (ppm) water by this test method. The validity of correcting measured water contents for known mercaptan/sulfide levels has not yet been determined.

• Supporting data are available from ASTM Headquarters, Request RR:D02-1246.

15. Keywords 15.1 coulometric; crude oils; homogenization; Karl Fischer; shear mixer; titration; water, water in crude oils

where: X = sample mean from 0.005 to 5 mass %. 14.1.1.2 For a volume sample, r = 0.056 (X2/3)

(3)

756

~

D 4928

ANNEX

(Mandatory Information) A1. HOMOGENIZATION EFFICIENCY OF UNKNOWN MIXER the water content of the crude immediately after mixing. Sample the crude just below the liquid level. A I.4 Without additionally mixing the crude, determine the water content (single determination) of the crude 15 and 30 min after the initial mixing in AI.3. AI.5 The water contents (added plus inherent) of these three portions (immediately, 15 and 30 min after homogenization) shall agree within 0.10 % absolute of each other and within 0.10 % of the calculated water content (that is, added plus inherent). If they do not agree, then the homogenization must be repeated on fresh portions of crude and water in a clean container while changing the power, mixing time, or the height of the mixer shaft or a combination thereof, until the chosen conditions result in a mixture that yields the required agreement. These conditions of power, mixing time and depth of immersion of the mixer shaft are then to be used for all subsequent mixings. AI.6 The mixing conditions shall be evaluated for all new crudes and repeated periodically for known etudes spiked with water to 4 to 5 mass % to check that the conditions remain effective. AI.7 This procedure need not be effective for crudes with abnormally low or high viscosity at room temperature. These crudes can require special treatment in order to obtain stable water-in-crude emulsions. NOTe Al.l--Some crudes cannot hold a stable water emulsion for the 15 and 30 min described. In somecases the crude oil can be cooled below room temperature to improve the stability of the emulsion. Alternatively,additionaltestingis neededto determinethe time period over which the emulsion is stable for a given set of mixing conditions. The test specimen should be taken within the stability period estabfished.

A I.I The homogenization efficiency of each unknown mixer must be evaluated before use. To evaluate the mixer, confirm that the expected water content can be obtained by the Karl Fischer titration following the addition of a known amount of water to a nominally dry crude and the homogenization of this mixture. This procedure for checking the homogenization efficiency of a mixer is based upon the use of about a 500-mL sample container, however a similar procedure must be followed for the different sample sizes that may be received in a particular laboratory. A 1.2 Weigh the 500-mL sample container to the nearest 0.01 g. Fill the container to about 80 % with the dry crude (less than 0.1 mass % water). Insert the mixer shaft into the container so that the head is about 5 mm from the container bottom. Homogenize the contents of the container at 80 % power for 2 rain, take test aliquot of the resulting emulsion, and determine its water content in duplicate (see 11.2.1). Obtain the average of the duplicate results and designate this as the inherent water content. AI.3 Weigh the crude and container to the nearest 0.01 g. Record the temperature of the oil to the nearest I°C. Immerse the mixer in the crude as in A I.2. Knowing the mass of the crude, add enough water using a Grade A pipet to raise the water content about 4 to 5 % above the base level found in AI.2. Homogenize the oil and water at 80 % power for 2 rain. Record the temperature of the emulsion immediately after homogenization. The rise in temperature during homogenization is not to exceed 10"C otherwise loss of water can occur and the emulsion can be destabilized. Determine

APPENDIX

(Nonmandatory Information) Xl. ALTERNATIVE TEST METHOD USING VOLUMETRIC DETERMINATION OF SAMPLE SIZE Xl.1 Scope X 1.1.1 This alternative test method covers the determination of water in crude oils as described in test method D 4928 with the exception that a volumetric measure is used for the test specimen of crude injected into the titration vessel. This alternative test method is applicable only when conditions warrant, that is, when the vapor pressure and viscosity of the crude oil permit an accurate determination of the volume of crude oil. Another necessary criterion for the application of this alternative is that both parties involved in the purchase, sale, or transfer of the crude oil agree to its use. NoTe X l.I--This alternative test method involvingthe volumetric measure of the test specimen is under furtherreviewby the responsible 757

ASTM Subcommitteeand by the correspondingAPI committee.These committeesare solicitingadditionaldata comparingresults obtainedby this test method using both the mass and volumetric procedures for measuringthe test specimen.Theseatudiesmay result in action to leave the appendixas published, to movethe appendixinto the main body of the test method,or to remove the appendix from the method. X 1.1.2 The referee procedure for determination of water in crude oils by eoulometric Karl Fischer titration is the D 4928 procedure which uses a mass measurement of the crude oil test specimen.

X1.2 Summary of Test Method X I.2.1 After homogenization of the crude oil with a

~

D 4928

mixer, a volume aliquot of the crude is titrated to an electrometric end point using a coulometric Karl Fischer apparatus. The procedures described in D 4928 are followed except as noted in Xl.3 to X1.8.

where: V~ = volume of water titrated, pL and V2 = volume of sample, mL. NOTE X 1.l--The volumeof watertitrated is the p g of water r e p o r t e d by the coulometrictitrator.

XI.3 Interferences X 1.3.1 The presence of gas bubbles in the syringe can be a source of uncertainty. The tendency of the crude to form gas bubbles is a function of crude type and corresponding vapor pressure. Viscous etudes can prove to be difficult to measure with a precision syringe.

X1.7 Report X1.7.1 Report the water content to the nearest 0.01 volume % as: volume % water by ASTM D 4928, Appendix XI. XI.7.2 The inclusion of the reference to Appendix XI in reporting the volume percent water is mandatory if this alternative procedure is used.

X1.4 Apparatus XI.4.1 Syringe, 10-pL with a needle long enough to dip below the surface of the anode solution when inserted through the inlet port septum, and graduated for readings to the nearest 0.01 pL or better. XI.4.2 Syringes, 250 pL, 500 pL, and 1 mL capacities and accurate to the nearest 1 pL, 1 pL, and 0.01 mL, respectively. A quality, gas tight, glass syringe with teflon plunger and LEUR fittings is recommended.

X1.8 Precision and Biass X I.8.1 The precision of this test method as determined by the statistical examination of inteflaboratory test results is as follows. XI.8.1.1 Repeatability--The difference between two single and independent results obtained by the same operator with the same apparatus under constant operating conditions on identical test material would, in the long run, in the normal and correct operation of the test method, exceed the following values only in one case in twenty (see Table XI.2). r - 0.056 (X213) (XI.2)

X1.5 Procedure X 1.5. l Add the test specimen of crude oil to the titration vessel immediately after the mixing step described in 8.4 using the following method (see Table X 1.1). XI.5.1.1 Starting with a clean, dry syringe of suitable capacity (see Table X 1.1, Note X 1.2), withdraw at least three portions of the sample and discard to waste. Immediately withdraw a further portion of sample, clean the needle with paper tissue and record the volume of the syringe to the nearest 1 or 10 pL as appropriate (see X 1.4). Insert the needle through the inlet port septum, start the titration and with the tip of the needle just below the liquid surface, inject the entire contents of the syringe. Withdraw the syringe. After the endpoint is reached, record the titrated water from the digital readout on the instrument.

where: X ffi the sample mean from 0.005 to 5 volume %. XI.8.1.2 Reproducibility.--The difference between two single and independent results obtained by different operators working in different laboratories on identical test material would, in the long run, exceed the following values only in one case in twenty (see Table X 1.2). R - 0.112 (X2/3) (XI.3) where: X ffi the sample mean from 0.005 to 5 volume %. XI.8.2 Bias--No significant difference was found between the average water content obtained by this test method and the expected water content (based on the amount of added water) for the crude oil samples analyzed in the round robin used to evaluate the precision6 of this test method.

NOTE X 1.2--If the concentration of water in the sample is completely unknown, it is advisable to start with a small trial portion of sample to avoid excessive titration times and depletion of the reagents. Further adjustment of the test specimen size can then be made as necessary.

TABLE Xl.2

X1.6 Calculation X I.6.1 Calculate the water content of the sample as follows: Water, Volume % = TABLE X1.1

VI i0 000 x V2

(X I. 1)

A p p r o x i m a t e T e s t Specimen Size Based on

Expected Water Content Expected Water Content, Vol Yo

Sample Size mL

0.005-0.1 0.10-0.5 0.50-5.0

1.00 0.50 0.25

pg Water Titrated 200-1000 500-2500 1250-12 500

Precision * Intervals

Volume ~t Water

r

R

0.02 0.05 0.10 0.30 0.50 0.70 1.00 1.50 2,00 2.50 3.00 3.50 4.00 4,50 5.00

0.004 0.008 0.01 0.03 0.04 0.04 0.06 0.07 0.09 0.10 0.12 0.13 0.14 0.15 0.18

0.008 0.015 0.02 0.05 0.07 0.09 0.11 0.15 0.18 0.21 0,23 0.26 0.28 0.31 0.33

A r - repeatability, and R - reproducibility.

758

4@) D 4928 The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that datarrntnaticn of the validity of any such patent rights, and the risk of Infringen~ent of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed avery five years and ff not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your o~rnrnents will receive careful consideration at a meeting of the responsible technical committee, which you may attend, ff you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 100 Barr Harbor Drive, West Conshohocken, PA 19428.

759

Designation: D 4929 - 94

An American National Standard

Standard Test Methods for Determination of Organic Chloride Content in Crude Oil I This standard is issued under the fixed designation D 4929; the number immediately fol|owing the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (0 indicates an editorial change since the last revision or reapproval.

tion of the organic chloride in the washed naphtha fraction, as follows. 3.2.1 Test Method .4, Sodium Biphenyl Reduction and Potentiometry--The washed naphtha fraction of a crude oil specimen is weighed and transferred to a separatory funnel containing sodium biphenyl reagent in toluene. The reagent is an addition compound of sodium and bipbenyl in ethylene glycol dimethyl ether. The free radical nature of this reagent promotes very rapid conversion of the organic halogen to inorganic halide. In effect this reagent solubilizes metallic sodium in organic compounds. The excess reagent is decomposed, the mixture acidified, and the phases separated. The aqueous phase is evaporated to 25 to 30 mL, acetone is added, and the solution titrated potentiometrically. 3.2.2 Test Method B, Combustion and Microcoulometry---The washed naphtha fraction of a crude oil specimen is injected into a flowing stream of gas containing about 80 % oxygen and 20 % inert gas such as argon, helium, or nitrogen. The gas and sample flow through a combustion tube maintained at about 800"C. The chlorine is convened to chloride and oxychlorides which then flow into a titration cell where they react with the silver ions in the titration cell. The silver ions thus consumed are coulometrically replaced. The total current required to replace the silver ions is a measure of the chlorine present in the injected samples. 3.2.3 The reaction occurring in the titration cell as chloride enters is as follows: CI- + Ag+ --, AgCI (s)

1. Scope I. l These test methods cover the determination of organic chloride (above 1 ~tg/g organically-bound chlorine) in crude oils, using either distillation and sodium biphenyl reduction or distillation and microcoulometry. 1.2 These test methods involve the distillation of crude oil test specimens to obtain a naphtha fraction prior to chloride determination. The chloride content of the naphtha fraction of the whole crude oil can thereby be obtained. 1.3 Test Method A covers the determination of organic chloride in the washed naphtha fraction of crude oil by sodium biphenyl reduction followed by potentiometric titration. 1.4 Test Method B covers the determination of organic chloride in the washed naphtha fraction of crude oil by oxidative combustion followed by microcoulometfic titration. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 1.6 The preferred concentration units are micrograms per gram of chloride. 2. Referenced Documents

2.1 ASTM Standards: D 86 Test Method for Distillation of Petroleum Products 2 D 1193 Specification for Reagent Water a D4057 Practice for Manual Sampling of Petroleum and Petroleum Products 4 D 4177 Practice for Automatic Sampling of Petroleum and Petroleum Products 4

3.2.4 The silver ion consumed in the above reaction is generated coulometrically thus: Ag" ---, Ag+ + e3.2.5 These microequivalents of silver are equal to the number of microequivalents of titratable sample ion entering the titration cell.

3. Summary of Test Methods

3.1 A crude oil distillation is performed to obtain the naphtha cut at 204°C (400OF). The distillation method was adapted from Test Method D 86 for the distillation of petroleum products. The naphtha cut is washed successively with caustic and water to remove hydrogen sulfide and inorganic chlorides. 3.2 There are two alternative test methods for determina-

4. Interferences 4.1 Test MethodA--Other titratable halides will also give a positive response. These titratable halides include HBr and HI. 4.2 Test Method B--Other titratable halides will also give a positive response. These titratable halides include HBr and HI (HOBr and HOI do not precipitate silver). Since these oxyhalides do not react in the titration cell, approximately 50 % microequivalent response is detected. 4.2.1 This test method is applicable in the presence of total sulfur concentration of up to l0 000 times the chlorine level.

' These test methods are under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcom. mittee 1:)02.03 on Elemental Analysis. Current edition approved Apr. 15, 1994. Published June 1994. Originally published as D 4929 - 89. Last edition D 4929 - 89. "Annual Book of ASTM Standards, Vol 05.01. 3 Annual Book of ASTM Standards, Vol I 1.01. 4 Annual Book of ASTM Standards, Vol 05.02.

760

t~) D 4929 8. Reagents and Materials 8.1 Acetone, chloride-free. 8.2 Caustic Solution, 1 M potassium hydroxide prepared in distilled/deionized water. 8.3 Distilled/Deionized Water. 8.4 Filter Paper,6 Whatman No. 41 or equivalent. 8.5 Stopcock Grease.7 8.6 Toluene, chloride-free.

5. Significance and Use 5.1 Organic chloride species are potentially damaging to refinery processes. Hydrochloric acid can be produced in hydrotreating or reforming reactors and the acid accumulates in condensing regions of the refinery. Unexpected concentrations of organic chlorides cannot be effectively neutralized and damage can result. Organic chlorides are not known to be naturally present in crude oils and usually result from cleaning operations at producing sites, pipelines, or tanks. It is important for the oil industry to have common methods available for the determination of organic chlorides in crude oil, particularly when transfer of custody is involved.

9. Sampling 9.1 Obtain a test unit in accordance with Practice D 4057 or Test Method D 4177. To preserve volatile components which are in some samples, do not uncover samples any longer than necessary. Samples should be analyzed as soon as possible, after taking from bulk supplies, to prevent loss of organic chloride or contamination due to exposure or contact with sample container. NOTEI: WarningmSamples that are collectedat temperatures below room temperature may undergo expansion and rupture the container. For such samples, do not fill the containerto the top, leavesufficientair space above the sample to allow room for expansion. 9.2 If the test unit is not used immediately, then thoroughly mix in its container prior to taking a test specimen. Some test units can require heating in order to thoroughly homogenize.

6. Purity of Reagents

6. I Purity of ReagentsRReagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, where such specifications are available. 5 Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination. 6.2 Purity of WatermUnless otherwise indicated, references to water shall be understood to mean reagent water as defined by Type III of Specification D 1193.

10. Preparation of Apparatus 10.1 Clean all glassware by rinsing successively with toluene and acetone. After completing the rinse, dry the glassware using a stream of dry nitrogen gas. Obtain and record the masses of the round-bottom flask and receiving cylinder. Assemble the glass distillation apparatus using stopcock grease to seal all joints and wire clamps to prevent loosening of the joints. Adjust the thermometer position within the adapter tee such that the lower end of the capillary is level with the highest point on the bottom ofthe inner wall of the adapter tee section which connects to the condenser. NOTE 2--A diagram illustrating the appropriate positioning of the thermometer can be found in Test Method D 86. 10.2 Form the copper tubing into a coil to fit inside the receiver flask, leaving room in the center of the flask for the receiving cylinder. With the PVC tubing, connect one end of the copper coil to the water source, and connect the other end of the coil to the lower fitting of the Liebig condenser cooling jacket. Connect the upper condenser fitting to the water drain. Fill the receiver flask with an ice/water mixture and turn on the water. Maintain the temperature of the condenser below 10*C.

DISTILLATION AND CLEANUP PROCEDURE

7. Apparatus

7.1 Round-Bottom Boiling Flask, borosilicate, 1-L, single short neck with 24/40 outer ground-glass joint. 7.2 Tee Adapter, borosilicate, 75* angle side-arm, 24/40 ground-glass joints. 7.3 Thermometer, ASTM thermometer 2F, 20*F to 580"F range. 7.4 Thermometer Adapter, borosilicate, 24/40 inner ground-glass joint. 7.5 Liebig Condenser, borosilicate, 300-mm length, 24/40 ground-glass joints. 7.6 Vacuum Take-Off Adapter, borosilicate, 105" angle bend, 24/40 ground-glass joints. 7.7 Receiving Cylinder, borosilicate, 250-mL capacity, 24/40 outer ground-glass joint. 7.8 Wire Clamps, for No. 24 ground-glass joints, stainless steel. 7.9 Receiver Flask, for ice bath, 4-L. 7.10 Copper Tubing, for heat exchanger to cool condenser water, 6.4-mm outside diameter, 3-m length. 7.11 Electric Heating Mantle, Glas-Col Series 0, I-L size, 140-W upper heating element, 380-W lower heating element. 7.12 Variacs, 2, for temperature control of upper and lower heating elements, 120 V, 10 amps.

11. Procedure 1 I. 1 Add a 500-mL crude oil test specimen to tared round bottom flask. Obtain and record the mass of the crude oil-filled flask to the nearest 0.1 g. Connect the flask to the distillation apparatus. Place the heating mantle around the flask, and support the heating mantle/flask from the bottom. Connect the heating mantle to the variacs. Turn on the variacs and start the distillation. During the distillation,

s Reagent Chemicals. American Chemical Society Specifications, American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed by the American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville, MD.

6 Whatman No. 41 has been found satisfactory. An equivalent may be used. 7 Dow Coming silicone has been found satisfactory.

761

(~ D 4929 adjust the variac settings to give a distillation rate of approximately 5 mL/min. Continue the distillation until a thermometer reading of 400*F (204"C) is attained. When the temperature reaches 400*F, end the distillation by first disconnecting and removing the receiving cylinder. After the receiving cylinder has been removed, turn offthe variacs and remove the heating mantle from the flask. Obtain and record the mass of the receiving cylinder and distillate. 11.2 Transfer the naphtha fraction from the receiving cylinder to the separatory funnel. Using the separatory funnel, wash the naphtha fraction three times with equal volumes of th~ caustic solution (l M KOH). Follow the caustic wash With a water wash, again washing three times with equal volumes. The caustic wash removes hydrogen sulfide, while the water wash removes traces of inorganic chlorides either originally present in the crude or from impurities in the caustic solution. After the washings are complete, flter the naphtha fraction to remove residual free-standing water. Store the naphtha fraction in a clean glass bottle. This naphtha fraction can now be analyzed for organic chlorides by either sodium biphenyl or combustion/ microcoulomet~c techniques. 11.3 Measure the density of the crude oil specimen and the naphtha fraction by obtaining the mass of 10.0 mL (using. a 10-mL volumetric flask) of each to the nearest 0.1 g.

12. Calculation 12.1 Calculate naphtha fraction as follows:

f= g./gc where: f = mass fraction of naphtha collected, M, = mass of naphtha collected, and Mc = mass of crude oil specimen. 12.2 Calculate the density as follows: Density, g/mL = m/v where: m -- mass of sample specimen, g, and v = volume of sample specimen, mL. TEST METHOD

(i)

(2)

A--SODIUM BIPHENYL REDUCTION AND POTENTIOMETRY

13. Apparatus 13.1 Electrodes: 13.1.1 Glass, general purpose, s 13.1.2 Silver-Silver Chloride, billet-type. 13.2 Titrator, potentiometric. The titrator is equipped with a 5-mL or smaller buret and a magnetic stirring motor. 14. Reagents and Materials 14.1 Acetone, chloride-free. 14.2 Congo Red Paper. 14.3 Isooctane, ASTM knock-test grade. 14.4 Nitric Acid, approximately 5 M. Add 160 mL of concentrated nitric acid to about 200 mL of water and dilute to 500 mL. 14.5 2-Propanol, chloride-free. 14.6 Silver Nitrate, 0.01 M, standard aqueous solution.

14.7 Sodium Biphenyl Reagent9"This is packed in 0.5-oz French square bottles (hereafter referred to as vials). The entire contents of one vial are used for each analysis. One vial contains 13 to 15 meq of active sodium. Store the sodium biphenyl reagent in a cool storage area, but do not refrigerate. Prior to using, warm the reagent to approximately 50"C and shake thoroughly to ensure a homogeneous liquid. 14.8 Toluene, chloride-free.

15. Preparation of Apparatus 15.1 Recoating Silver-Silver Chloride Electrodes--Clean the metal Surfaces of a pair of silver-silver chloride electrodes with mild detergent and scouring powder. Rinse the electrodes in distilled water. Immerse the metallic tips in saturated potassium chloride solution. Connect one electrode to the positive pole of a 1.5-V battery and the other to the negative pole. Reverse the polarity for several intervals of a few seconds each to alternately clean and recoat the receptor electrode (connected to the positive pole). When adequately coated, the receptor electrode tip will turn violet in color. This results from the action of light on the fresh silver chloride. 16. Procedure 16.1 Use extreme care to prevent contamination. Reserve all glassware for the chloride determination. Rinse glassware with distilled water followed by acetone just prior to use. Avoid using chlorine-containing stopcock greases such as chlorotrifluoroethylene polymer grease. 16.2 Place 50 mL of toluene in a 250-mL separatory funnel and add the contents of one vial of sodium biphenyl reagent. Swirl to mix and add about 30 g, obtaining the mass to the nearest 0.1 g of the washed naphtha fraction of crude oil sample. Obtain the mass of the sample bottle to deter, mine the exact amount taken. Stopper the separatory funnel and swirl to mix the contents thoroughly. The solution or suspension that results should be blue-green in color. When it is not, add more sodium biphenyl reagent (one vial at a time) until the solution or suspension is blue-green. 16.3 Allow 10 min after mixing for the reaction to be completed, then add 2 mL of 2-propanol and swirl gently with the funnel unstoppered for a time until the blue-green color changes to white, indicating that no free sodium remains. Stopper the funnel and rock it gently, venting pressure frequently through the stopcock. Thenadd 20 mL of water and 1O mL of 5 M nitric acid. Shake gently, releasing the pressure frequently through the stopcock. Test the aqueous phase with Con~o red paper. If the paper does not turn blue, add additional 5 M nitric acid in 5-mL portions until the blue color is obtained. 16.4 Drain the aqueous phase into another separatory funnel containing 50 mL of isooctane and shake well. Drain the aqueous phase into a 250-mL titration beaker. Make a second extraction of the sample-and-isooctane mixture with 25 mL of water that has been acidified with a few drops of 5 M nitric acid. Add this second extract to the 250-mL 9 Available from Southwestern Analytical Chemicals, P.O. Box 485, Austin, TX.

s Beckman No. 41262 has been found satisfactory. An equivalent may be used.

762

({~ D 4929 18.4 Microcoulometer--Having variable gain and bias control, and capable of measuring the potential of the sensing-reference electrode pair, and of comparing this potential with a bias potential, and of applying the amplified difference to the working-auxiliary electrode pair so as to generate a titrant. The microcoulometer output signal shall be proportional to the generating current. The microcoulometer may have a digital meter and circuitry to convert this output signal directly to nanograms or micrograms of chloride. 18.5 Sampling Syringe--A microliter syringe of 50-gL capacity capable of accurately delivering 5 to 50 gL of sample into the pyrolysis tube. A 3- or 6-in. (76.2 or 152.4 mm) needle is recommended to reach the inlet zone of approximately 500°C in the combustion zone. 18.6 A constant rate syringe pump or manual dispensing adaptor may be used to facilitate slow injection of the sample into the combustion tube. It is recommended that the injection rate not exceed 0.5 gL/s.

titration beaker. Evaporate the solution on a hot plate kept just below the boiling point of the liquid until 25 to 30 mL remains. Do not boil or evaporate to less than 25 mL as loss of chloride may occur. 16.5 Cool the solution and add 100 mL of acetone. Titrate the solution potentiometrically with standard 0.01 M silver nitrate, using glass versus silver-silver chloride electrodes. If an automatic titrator, such as a Metrohm, is available, use the semi-micro 5-mL piston buret. If the titration is carried out with a manually-operated pH meter, use a 5-mL semi-micro buret which can be estimated to three decimal places in millilitres. 16.6 Determine the endpoint for the manual titration by plotting the data showing emf versus volume of silver nitrate solution used. Determine the endpoint for the automatic titrator from the midpoint of the inflection of the titration curve.

16.7 Determine a blank for each group of test specimens by using all of the reagents, including the sodium biphenyl, and following all ~he operations of the analysis except that the sample itself is omitted.

19. Reagents and Materials

19. l Acetic Acid, glacial acetic acid. 19.2 Argon, Helium, Nitrogen, or Carbon Dioxide, high purity grade (HP) used as the carder gas. 19.3 Cell Electrolyte Solution, 70 % acetic acid, combine 300 mL reagent water (6.2) with 700 mL acetic acid (19.1) and mix well. 19.4 Chlorine, Standard Stock Solution, 1000 mg chlorine per litre, accurately dispense 1.587 g of chlorobenzene into a 500-mL volumetric flask and dilute to volume with

17. Calculation 17.1 Calculate chloride concentration in the naphtha fraction as follows: Chloride~ gg/g =

(A - B) (34) (35 460) W

(3)

where: A = volume of titrant for the sample specimen, mL, B = volume of titrant for the blank, mL, M = molarity of silver nitrate, and W = mass of sample specimen, g. 17.2 The concentration of organic chloride in the original crude oil sample specimen can be obtained by multiplying the chloride concentration in the naphtha fraction (17.1) by the naphtha fraction (12.1).

isooctane. 19.5 Chlorine, Standard Solution, 10 mg chlorine per litre, pipet 1.0 mL of chlorine stock solution (19.4) into a 100-mL volumetric flask and dilute to volume with isooctane. 19.6 Chlorobenzene, reagent grade. 19.7 Gas Regulators, two-stage gas regulator must be used on the reactant and carrier gas. 19.8 lsooctane, 2,2,4-trimethylpentane, reagent grade. 19.9 Oxygen, high purity grade, used as the reactant gas. 19.10 Silver Acetate, powder purified for saturated reference electrode.

TEST METHOD B--COMBUSTION AND MICROCOULOMETRY

18. Apparatus

18.1 Combustion Furnace--The sample specimen is to be oxidized in an electric furnace capable of maintaining a temperature of 800"C to oxidize the organic matrix. 18.2 Combustion Tube--Fabricated from quartz and constructed so a sample, which is vaporized completely in the inlet section, is swept into the oxidation zone by an inert gas where it mixes with oxygen and is burned. The inlet end of the tube shall hold a septum for syringe entry of the sample and side arms for the introduction of oxygen and inert gases. The center section is to be of sufficient volume to ensure complete oxidation of the sample. 18.3 Titration Cell--Containing a sensor-reference pair of electrodes to detect changes in silver ion concentration and a generator anode-cathode pair of electrodes to maintain constant silver ion concentration and an inlet for a gaseous sample from the pyrolysis tube. The sensor, reference, and anode electrodes shall be silver electrodes. The cathode electrode shall be a platinum wire. The reference electrode resides in a saturated silver acetate half-cell. The electrolyte contains 70 % acetic acid in water.

20. Preparation of Apparatus

20.1 Set up the analyzer in accordance with the equipment manufacturer instructions. 20.2 The typical operational conditions are as follows: Reactantgas flow,02 160 mL/min Carrier gas flow 40 rnL/rnin Furnacetemperature: Inlet zone 700"C Center and outletzones 800"C Coulometer:

Biasvoltage,mV 240-265 Gain ca. 1200 20.3 Optimize the bias voltage setting for the titration cell null-point by injecting 30 microliters of chloride-free water directly into the titration cell using a 6-inch needle. Adjust bias up or down to minimize the total integrated value due to this dilution effect. 21. Procedure 21.1 Fill a 50-gL syringe with about 30 to 40 gL of the 763

~) D 4929 sample of washed naphtha fraction of crude oil, being careful to eliminate bubbles. Then retract the plunger so that the lower liquid meniscus falls on the 5-1xLmark, and record the volume of liquid in the syringe. After the sample has been injected, again retract the plunger so that the lower liquid meniscus falls on the 5-lxL mark, and record the volume of liquid in the syringe. The difference in the two volume readings is the volume of sample injected. 21.2 Alternately, obtain the sample injection device mass before and after injection to determine the amount of sample injected. This method provides greater precision than the volume delivery method, provided a balance with a precision of ±0.01 mg is used and the syringe is carefully handled to obtain repeatable weighings. 21.3 Inject the sample into the pyrolysis tub8 at a rate not to exceed 0.5 laL/s. 21.4 Below 5 Ixg/g, the needle-septum blank will become increasingly more obvious. To improye precision insert the syringe needle into the hot inlet and then wait until the needle-septum blank is titrated before injecting the sample or standard. 21.5 For specimens containing more than 25 ~tg/g CI only 5.0 ~tL of sample need be injected. 21.6 Verify the system recovery, the fraction of chlorine in the standard that is titrated, every four hours by using the standard solution (19.5). System recovery is typically 85 % or better. 21.7 Repeat the measurement of the calibration standard at least three times. 21.8 Check the system blank daily with ieagent grade isooctane (19.8). Subtract the system blank from both sampl~and standard data. The system blank is typically less than 0.2 ~tg/g chlorine once the needle-septum blank has been titrated (21.4).

Chlorine, ltg/g = (A) (X) (0.367) _ B (R) (D (M) (RE)

where: A -- area in appropriate units, X = recorder sensitivity for full-scale response, mV, 35.45 $Cl/eq) (10 -3 V/mV) (106 ~tg,/g) 0.367 = (96 500 coulombs/eq) R = resistance, r, Y = area equivalence for a full-scale response on the recorder per second-area "mits per second, M = mass of sample, g, RF ffi recovery factor, and B = system blank, )xg/g CI. 22.2 The concentration of organic chloride in the original crude oil sample specimen can be obtained by multiplying the chloride concentration in the naphtha fraction (22.1) by the naphtha fraction (12.1). 23. Precision and Bias t°

22. Calculation

22.1 Calculate chloride concentration in the naphtha fraction as follows: 22.1.1 For microcoulometers which read directly in nanograms of chloride, the following equations apply: Sample Readout BlankReadout Chlorine, ~tg,/g= (4) (V) (D) (RF) (V) (D) (RF) or

Chlorine, lxg/g =

Sample Readout (M) (RE)

Blank Readout (M) (R-,D

(6)

(5)

where: Readout = displayed integrated value (sample/standard/ blank), V = volume injected ~tL, D = density,' g/m~ (11.3), RF = r e c o v ~ f~tctor, ~ation of chlorine determined in standardf ~livided by known standard content mirms the system blank.

23.1 Precision--The precision of these test methods as determined by the statistical examination of the inteflaboratory test results is as follows: 23.1.1 Repeatability--The difference between successive results obtained by the same operator with the same apparatus under constant operating conditions on identical test materials would, in the long run, in the normal and correct operation exceed the following values only in one case in twenty. 23.1.1.1 Test Method AmValues can be obtained for organically-bound chlorine for any given concentration above I ~tg/g Cl (in the original crude oil specimen) as follows: r = 0.3 [CI] 0'64 23.1.1.2 Test Method B--Values can be obtained for organically-bound chlorine for any given concentration above 1 ~tg/g CI (in the original crude oil specimen) as follows: r = 0.7 [el] 0'6

23.1.2 ReproducibilitymThe difference between two single and independent results obtained by different operators working in different laboratories on identical material would, in the long run, exceed the following values only in one case in twenty. 23.1.2.1 Test Method A--Values can be obtained for organically-bound chlorine for any given concentration above 1 ~tg/g CI (in the original crude oil specimen) as follows: R--

1.1 [el] 0"36

23.1.2.2 Test Method BmValues can be obtained for organically-bound chlorine for any given concentration above 1 }tg/g CI (in the original crude oil specimen) as follows:

Standard Readout Blank Readout (V) (D) (Cs) (V) (D) (C,) M -- mass of sample specimen, mg, and = concentration of standard, mg/L 22.1.2 For microcoulometers with only analog signal output to a recorder the following equation applies:

R ffi I,.0 [CI]° m

RF=

23.2 Bias--The bias for either Test Method A or B has been demonstrated by performing analyses using known to

764

Supporting data available from ASTM Headquarters Request RR:D02-1293.

~

D 4929

Recovery of Organic Chloride Spikes Chloride Concentration, mg/kg 14 12 10 8 6 4 2 01 0

2

4

6

8

10

12

14

Spiked Concentration, mg/kg CI - ' - - Expected Chloride

--+- Recovered Chloride

FIG. 1 Recovery~ofOrganicChlorideSpikes spiked concentrations of various organic chloride compounds in a variety of crude oils to be lower than the true value. This is due to ,the fact that not all of the volatile components will distill ?rom a complex crude oil under the conditions of this method. The extent of this bias is shown in Fig. l, where various recoveries are shown plotted against the

known concentration of pure organic-chloride compound spikes. 24. Keywords 24.1 coulometry; crude nil; organic-chloride; organochlorine; sodium biphenyl

The American Society for Testing and Materials takes no position respecting the validity of any patent rights aseerted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility, This standard is subject to revision at any time by the r~ponsible technical committee and must be reviewed every five years and ff not revised, either reapproved or withdrawn. Your comments ere invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at • meeting of the responsible technical committee, which you may attend, ff you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103.

765

Designation: D 4951 - 96

An A m e ~

Natlon~ Ste~:lard

Standard Test Method for Determination of Additive Elements in Lubricating Oils by Inductively Coupled Plasma Atomic Emission Spectrometry 1 This standard is issued under the fixed designation D 4951; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (~) indicates an editorialchange since the last revision or reapproval.

1. Scope I. 1 This test method covers the quantitative determination of barium, boron, calcium, copper, magnesium, phosphorus, sulfur, and zinc in unused lubricating oils and additive packages. 1.2 The precision statements are valid for dilutions in which the mass % sample in solvent is held constant in the range of I to 5 mass % oil. 1.3 The precision tables define the concentration ranges covered in the inteflaboratory study. However, both lower and higher concentrations can be determined by this test method. The low concentration limits are dependent on the sensitivity of the ICP instrument and the dilution factor. The high concentration limits are determined by the product of the maximum concentration defined by the linear calibration curve and the sample dilution factor. 1.4 Sulfur can be determined if the instrument can operate at a wavelength of 180 nm. 1.5 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. 1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

2. Referenced Documents 2.1 A S T M Standards: D 1552 Test Method for Sulfur in Petroleum Products (High-Temperature Method) 2 D 4057 Practice for Manual Sampling of Petroleum and Petroleum Products 3 D 4307 Practice for Preparation of Liquid Blends for Use as Analytical Standards 3 D4628 Test Method for Analysis of Barium, Calcium, Magnesium, and Zinc in Unused Lubricating Oils by Atomic Absorption Spectrometry 3 D 4927 Test Methods for Elemental Analysis of Lubricant and Additive Components--Barium, Calcium, Phos-

phorus, Sulfur, and Zinc by Wavelength-Dispersive X-Ray Fluorescence Spectroscopy4 D 5185 Test Method for Determination of Additive Elements, Wear Metals, and Contaminants in Used Lubricating Oils and Determination of Selected Elements by Inductively Coupled Plasma Atomic Emission Spectrometry4 E 135 Terminology Relating to Analytical Chemistry for Metals, Ores, and Related Materials s

3. Summary of Test Method 3.1 A sample portion is weighed and diluted by mass with mixed xylenes or other solvent. An internal standard, which is required, is either weighed separately into the test solution or is previously combined with the dilution solvent. Calibration standards are prepared similarly. The solutions are introduced to the ICP instrument by free aspiration or an optional peristaltic pump. By comparing emission intensities of elements in the test specimen with emission intensities measured with the calibration standards and by applying the appropriate internal standard correction, the concentrations of elements in the sample are calculable. 4. Significance and Use 4.1 This test usually requires several minutes per sample. This test method covers eight elements and thus provides more elemental composition data than Test Method D 4628 or Test Method D 4927. In addition, this test method provides more accurate results than Test Method D 5185, which is intended for used lubricating oils and base oils. 4.2 Additive packages are blends of individual additives, which can act as detergents, antioxidants, antiwear agents, etc. Many additives contain one or more elements covered by this test method. Additive package specifications are based, in part, on elemental composition. Lubricating oils are typically blends of additive packages, and their specifications are also determined, in part, by elemental composition. This test method can be used to determine if additive packages and unused lubricating oils meet specifications with respect to elemental composition.

5. Interferences 5.1 Spectral--There are no known spectral interferences between elements covered by this test method when using the spectral lines listed in Table I. However, if spectral interferences exist because of other interfering elements or

I This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.03 on Elemental Analysis. Current edition approved Nov. 10, 1995. Published January 1997. Originally published as D 4951 - 89. Last previous edition D 4951 - 95a. 2 Annual Book of ASTM Standards, Vol 05.01. Annual Book of ASTM Standards, Vol 05.02.

4 Annual Book of ASTM Standards, Vol 05.03. 5 Annual Book of ASTM Standards, Vol 03.05.

766

~ TABLE 1

D 4951 7.2 Base Oil, U.S.P. white oil, or a lubricating base oil that is free of analytes, with a viscosity of about 4 cSt at IO0°C.

Elements Determined and Suggested Wavelengths A

Element Barium

Boron a Calcium Copper Magnesium Phosphorusa Sulfur" Zinc

Wavelength, nm 233.53, 455.40, 493.41 182.59, 249.68 315.88, 317.93, 364.4, 422.67 324.75 279.08, 279.55, 285.21 177.51,178.29, 213.62, 214.91,253.40 180.73, 182.04, 182.62 202.55, 208.20, 213.86, 334.58, 481.05

NOTE 1: Caution--Lubricating base oils can contain sulfur. For preparation of sulfur standards and blending of additive packages, white oil is recommended.

7.3 Internal Standard, (Required)--An oil-soluble internal standard element is required. The following internal standards were successfully used in the interlaboratory study on precision: Ag, Be, Cd, Co (most common), La, Mn, Pb, Y. 7.40rganometallic StandardsmMulti-element standards, containing known concentrations (approximately 0.1 mass %) of each clement, can be prepared from the individual metal concentrates. Refer to Practice D 4307 for a procedure for preparation of multicomponent liquid blends. When preparing multi-element standards, be certain that proper mixing is achieved. Commercially available multi-element blends (with known concentrations of each element at approximately 0.1 mass %) are also satisfactory. 7.4.1 More than one multi-element standard can be necessary to cover all elements, and the user of this test method can select the combination of elements and their concentrations in the multi-element standards. It can be advantageous to select concentrations that are typical of unused oils. However, it is imperative that concentrations are selected such that the emission intensities measured with the working standards can be measured precisely (that is, the emission intensities are significantly greater than background) and that these standards represent the linear region of the calibration curve. Frequently, the instrument manufacturer publishes guidelines for determining linear range. 7.4.2 Some commercially available organometallic standards are prepared from metal sulfonates and therefore contain sulfur. For sulfur determinations, a separate sulfur standard can be required. A sulfur standard can be prepared by blending NIST SRM 1622 with white oil. 7.4.3 Metal sulfonates can be used as a sulfur standard if the sulfur content is known or determined by an appropriate test method such as Test Method D 1552. 7.4.4 Petroleum additives can also be used as organometallic standards if their use does not adversely affect precision nor introduce significant bias. 7.5 Dilution Solvent--Mixed xylenes, o-xylene, and kerosine were successfully used in the interlaboratory study on precision.

'~ These wavelengths are only suggested and do not represent all possible choices. a Wavelengths for boron, phosphorus, and sulfur below 190 nm require that a vacuum or inert gas purged optical path be used.

selection of other spectral lines, correct for the interference using the technique described in Test Method D 5185. 5.2 ViscosityIndex Improver Effect--Viscosity index improvers, which can be present in multi-grade lubricating oils, can bias measurements. However, the biases can be reduced to negligible proportion by using the specified solventto-sample dilution and an internal standard.

6. Apparatus 6.1 Inductively-Coupled Plasma Atomic Emission Spectrometer--Either a sequential or simultaneous spectrometer is suitable, if equipped with a quartz ICP torch and r-f generator to form and sustain the plasma. 6.2 Analytical Balance, capable of weighing to 0.001 g or 0.0001 g, capacity of 150 g. 6.3 Peristaltic Pump, (Recommended)--A peristaltic pump is strongly recommended to provide a constant flow of solution. The pumping speed must be in the range 0.5 to 3 mL/min. The pump tubing must be able to withstand at least 6 h exposure to the dilution solvent. Fluoroelastomer copolymer6 tubing is recommended. 6.4 Solvent Dispenser, (Optional)--A solvent dispenser calibrated to deliver the required weight of diluent can be advantageous. Ensure that solvent drip does not affect accuracy. 6.5 Specimen Solution Containers, 30 to 120 mL, glass or polyolefin vials or bottles, with screw caps. 6.6 Vortexer, (Optional)--Vortex the sample plus diluent mixture until the sample is completely dissolved. 6.7 Ultrasonic Homogenizer, Optional--A bath-type or probe-type ultrasonic homogenizer can be used to homogenizer the test specimen. 7. Reagents and Materials

7.1 Purity of ReagentsmReagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society where such specifications are available. 7

8. Internal Standardization (Required) 8.1 The internal standard procedure requires that every test solution (sample and standard) have the same concentration (or a known concentration) of an internal standard element that is not present in the original sample. The internal standard is usually combined with the dilution solvent. Internal standard compensation is typically handled in one of two different ways, which can be summarized as follows. 8. I. l Calibration curves are based on the measured inten-

6 Fluoroelastoraer copolymer is manufactured as Viton, a trademark owned by E. I. duPont de Nemours. Reagent Chemicals, American Chemical Society Specifications, American Chemical Society, Washington. DC. For suggestions on the testing of reagents not listed by the American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, O.K., and the United States Phar~opeia and National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville, MD,

767

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D 4951

sity of each analyte divided (that is, scaled) by the measured intensity of the internal standard per unit internal standard element concentration. Concentrations for each analyte in the test specimen solution are read directly from these calibration curves. 8.1.2 For each analyte and the internal standard element, calibration curves are based on measured (unsealed) intensities. Uncorrected concentrations for each analyte in the test specimen solution are read from these calibration curves. Corrected analyte concentrations are calculated by multiplying the uncorrected concentrations by a factor equal to the actual internal standard concentration divided by the uncorrected internal standard concentration determined by analysis. 8.2 Dissolve the organometallic compound representing the internal standard in dilution solvent and transfer to a dispensing vessel. The stability of this solution must be monitored and prepared fresh (typically weekly) when the concentration of the internal standard element changes significantly. The concentration of internal standard element shall be at least 100 times its detection limit. A concentration in the range of 10 to 20 mg/kg is typical. NOTE 2BThis test method specifies that the internal standard is combined with the dilution solventbecause this technique is common and efficient when preparing many samples. However, the internal standardcan be added separatelyfrom the dilutionsolventas longas the internal standard concentrationis constant or accuratelyknown.

9. Sampling 9.1 The objective of sampling is to obtain a test specimen that is representative of the entire quantity. Thus, take lab samples in accordance with the instructions in Practice D4057. The specific sampling technique can affect the accuracy of this test method. 10. Preparation of Apparatus 10.1 Instrument--Defign differences between instruments, ICP excitation sources, and different selected analytical wavelengths for individual spectrometers make it impractical to detail the operating conditions. Consult the manufacturer's instructions for operating the instrument with organic solvents. Set up the instrument for use with the particular dilution solvent chosen. 10.2 Peristaltic Pump--If a peristaltic pump is used, inspect the pump tubing and replace it, if necessary, before starting each day. Verify the solution uptake rate and adjust it to the desired rate. 10.3 ICP Excitation Source--Initiate the plasma source at least 30 min before performing an analysis. During this warm up period, nebulize dilution solvent. Inspect the torch for carbon build-up during the warm up period. If carbon build-up occurs, replace the torch immediately and consult the manufacturer's operating guide to take proper steps to remedy the situation. NOTE 3---Carbon that accumulates on the tip of the torch injector tube can be removed by using nebulizer gas that consists of approximately 1% oxygenin argon. 10.3. I Generally, carbon build-up can be minimized by increasing the intermediate argon flow rate or lowering the torch, or both, relative to the load coil. 768

NOTE 4--Some manufacturers recommend even longer warm up periods to minimizechangesin the slopesof the calibrationcurves.

10.4 Wavelength Profiling--Perform any wavelength profiling that is specified in the normal operation of the instrument. 10.5 Operating Parameters--Assign the appropriate operating parameters to the instrument task file so that the desired elements can be determined. Parameters to be included are element, wavelength, background correction points (optional), interelement correction factors (refer to 5. l), integration time, and internal standard compensation (required). Multiple integrations (typically three) are required for each measurement. A typical integration time is I0 s.

11. Preparation of Calibration Standards and Check Standards I1.1 Diluent--Diluent refers to the dilution solvent containing the internal standard (refer to 8.2). 11.2 The user of this test method has the option of selecting the dilution factor, that is, the relative amounts of sample and diluent. However, the mass % sample in diluent (for calibration standards and test specimens) must be constant throughout this test method, and the mass % sample in diluent must be in the range of I to 5 mass %. 11.2.1 All references to dilute and diluting in this test method refer to the user-selected dilution. 11.3 Blank--Prepare a blank by diluting the base oil or white oil with the diluent. 11.4 Working Standards--Weigh to the nearest 0.001 g, approximately 1 to 3 g of each multi-element standard (refer to 7.4) into separate bottles. Dilute by mass with the diluent. 11.5 Check Standard--Prepare instrument check standards in the same manner as the working standards such that the concentrations of elements in the check standards are similar to the concentrations of elements in the test specimen solutions. It is advisable to prepare the check standard from alternative sources of certified organometaUic standards.

12. Preparation of Test Specimens 12.1 Diluent--Diluent refers to the dilution solvent conraining the internal standard (refer to 8.2). 12.2 Test specimen solutions are prepared in the same way that calibration standards are prepared (refer to 11.2). The mass % oil in diluent must be the same for calibration standards and test specimen solutions. 12.2.1 Lubricating Oil SpecimensmWeigh approximately 0.5 g oil to the nearest 0.001 g and dilute by mass with the diluent. Mix well. 12.2.2 AdditivePackages--The concentrations ofadditive elements in additive packages are typically ten times the concentrations in lubricating oils. Therefore, additive packages are first blended with base oil before adding diluent. 12.2.2.1 Weigh approximately 0.5 g of the additive package to the nearest 0.001 g. Add approximately ten times this amount of base oil, weighed to the nearest 0.001 g. Dilute this mixture by mass with diluent. Mix well. 12.3 Record all weights and calculate dilution factors by dividing the sum of the weights of the diluent, sample, and base oil (if any) by the weight of the sample.

~

D 4951 TABLE 3 Reproducibility NOTE~X ==mean concentration, mass %.

TABLE 2 Repeatability NOTE--X "= mean concentration, mass %. Element Ba Ba B B Ca Ca Cu Cu Mg Mg P P S S Zn Zn

Range,mass • 0.13 3.4 0.01-0.02 0.11-0.13 0.012-0.18 0.8-4.1 0.01-0.02 0.11 0.05-0.14 0.35-0.82 0.05-0.12 0.7-1.3 0.3-0.8 3.0-3.2 0.05-0.13 0.7-1.4

Sample Oil Additive Oil Additive Oil Additive Oil Additive Oil Additive Oil Additive Oil Additive Oil Additive

Repeatability, mass 0.011 0.20 0.0017 0.0093 0.0145 (X + 0.152)°,aT 0.0363 X 0.0008 0.0054 0.0159 X°.7 0.0473 X 0.0254 X 0.0313 (X + 0.294) 0.016 0.14 0.0212 (X + 0.0041) 0.035

13. Calibration 13.1 The linear range of all calibration curves must be determined for the instrument being used. This is accomplished by running intermediate standards between the blank and the working standards and by running standards containing higher concentrations than the working standards. Analyses of test specimen solutions must be performed within the linear range of the calibration curve. 13.2 At the beginning of the analysis of each set of test specimen solutions, perform a two-point calibration using the blank and working standard. 13.3 Use the check standard to determine if each element is in calibration. When the results obtained with the check standard are within 5 % (relative) of the expected concentrations for all elements, proceed with the analysis. Otherwise, make any adjustments to the instrument that are necessary and repeat the calibration. 13.4 Calibration curves can be constructed differently, depending on the implementation of internal standard compensation. 13.4.1 When analyte intensities are ratioed to internal standard intensities, the calibration curve is, in effect, a plot of I(Re) versus analyte concentration and: l(Re) = (/(e) - l(Be))//(is) (1)

Element

Range,mass %

Sample

Reproducibility, mass

Ba Ba B B Ca Ca Cu Cu Mg Mg P P S S Zn Zn

0.13 3.4 0.01-0.02 0.11-0.13 0.012-0.18 0.8-4.1 0.01-0.02 0.11 0.05-0.14 0.35-0.82 0.05-0.12 0.7-1.3 0.3-.0.8 3.0-3.2 0.05-0.13 0.7-1.4

Oil Additive Oil Additive Oil Additive Oil Additive Oil Additive Oli Additive Oil Additive Oil Additive

0.019 0.66 0.0035 0.016 0.0208 (X + 0.152)0 a7 0.114 X 0.0017 0.016 0.0624 X°.r 0.198 X 0.101 X 0.115 (X + 0.294) 0.061 0.372 0.0694 (X + 0.0041) 0.115

TABLE 4

Calculated Precision, mass %, at Selected Concentrations, mass % Concentration

Element Ba B Ca Cu Mg P S Zn

0.01 repeatability reproducibility repeatability reproducibility repeatability reproducibility repeatability reproducibility repeatal:flllty reproducibility repeatability reproducibility repeatability reproducibility repeatability reproducibility

.0017 .0035 .0316 .0024 .0008 .0017

0.05

.0060 .0088 .0020 .0076 .0049 .0180

0.1 .011 .019 .0093 .016 .0105 .0154 .0054 .016 .0032 .0124 .0049 .0180

0.5

1.0

.038 .169 .024 .099 .940 .148 .016 ,061

.0011 .0037

.0022 .0072

.035 .115

linear range of the calibration, prepare another test specimen by mixing the sample with base oil before adding diluent (refer to 12.2.2.1, for example). Then, reanalyze. 14.3 Analyze the check standard after every fifth test specimen solution. If any result is not within 5 % of the expected concentration, recalibrate the instrument and reanalyze the test specimen solutions back to the previous acceptable check standard analysis.

where: I(Re) --- intensity ratio for analyte e, I(e) = intensity for analyte e, 1(Be) = intensity of the blank for analyte e, and I(is) = intensity of internal standard element. 13.4.2 When internal standard compensation is handled by multiplying all results for a certain test specimen by the ratio of the actual internal standard concentration to the determined internal standard concentration, the calibration curve is, in effect, a plot of (I(e) - 1(Be)) versus analyte concentration.

15. Calculation and Report 15.1 Calculate concentrations, based on sample, using Eq (1). Generally, the ICP software performs this calculation automatically. C = S x

(w~+ w2+ w3) w,

(1)

where: C = analyte concentration in the sample, mass %, S = analyte concentration in the test specimen, mass % (refer to Section 14), W l = sample mass, g, W2 -- diluent mass, g, and W3 = base oil mass (if any), g. 15.2 For each analyte, report mass % to three significant figures.

14. Analysis 14.1 Analyze the test specimen solutions in the same manner as the calibration standards (that is, same integration time, background correction points (optional), plasma conditions, etc.). Between test specimens nebulize dilution solvent for a minimum of 60 s. 14.2 When the concentration of any analyte exceeds the 769

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D 4951 background correction. The sample set comprised eight oils, five of which were multi=grade oils, and four additive packages. 16.1.1 Repeatabilitjx--The difference between two test results, obtained by the same operator with the same apparatus under constant operating conditions on identical test material would, in the long run, in the normal and correct operation of the test method, exceed the values in Table 2 only in one case in twenty. 16.1.2 Reproducibility--The difference between two single and independent results, obtained by different operators working in different laboratories on identical test materials, would in the long run, in the normal and correct operation of the test method, exceed the values in Table 3 only in one case in twenty.

16. Precision and Bias 8

16.1 The precision of this test method was determined by statistical analysis of interlaboratory results. Fourteen participating laboratories analyzed twelve samples in duplicate. Most laboratories performed the analyses at three different levels of dilution, namely, 1 mass % sample in solvent, 2 mass % sample and 5 mass % sample. In this study, dilution solvents were limited to mixed xylenes, o-xylene, and kerosine. The most common source of organometallic standards was metal sulfonates. Most laboratories used a peristaltic pump, and approximately half of the laboratories used s Intedaboratory study data are available from ASTM Headquarters. R.cqucst RR:D02-1349.

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned In this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reepproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend, ff you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 100 Barr Harbor Drive, West Conshohocken, PA 19428.

770

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Designation: D 4953 - 93

Standard Test Method for Vapor Pressure of Gasoline and Gasoline-Oxygenate Blends (Dry Method)l This standard is issued under the fixed designation D 4953; the number immediately following the designation indicates the year of odginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (~) indicates an editorial change since the last revision or reapproval. 1,

Scope

1.1 This test method, a modification of Test Method D 323 (Reid Method), provides two procedures to determine the vapor pressure (Note l) of gasoline and gasolineoxygenate blends. This test method is applicable to gasolines and gasoline-oxygenate blends with a vapor pressure range from 35 to 100 kPa (5 to 15 psi) (see Note 2). NOTE l--Because the external atmospheric pressure is counteracted by the atmospheric pressure initially present in the air chamber, this vapor pressure is an absolute pressure at 37.8"C (100*F) in kilopascals (pounds-forceper square inch). This vapor pressure differs from the true vapor pressure of the sample due to some small vaporization of the sample and air in the confined space. NOTE 2mVapor pressure of gasoline or gasoline-oxygenateblends below 35 kPa (5 psi) or greater than 100 kPa (15 psi) can be determined with this test method but the Precisionand Bias as described in Section 10 do not apply. For materials with a vapor pressure greater than 100 kPa (15 psi), use a 0 to 200 kPa (0 to 30 psi) gage as specified in the Annex of Test Method D 323. 1.3 The values stated in acceptable metric units are standard. The values given in parentheses are provided for information purposes only. 1.4 This standard does not purport to address all of the

safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Specific precautions are given in 6.5, and Notes 4, 6, 7, AI.1, and A1.2.

bath at 37.8"C (100*F) until a constant pressure is observed. The pressure reading, suitably corrected, is reported as the vapor pressure. 3.2 Procedure A utilizes the same apparatus and essentially the same procedure as Test Method D 323 with the exception that the interior surfaces of the liquid and vapor chambers are maintained completely free of water. Procedure B utilizes a semi-automatic apparatus with the liquid and vapor chambers identical in volume to those in Procedure A. The apparatus is suspended in a horizontal bath and rotated while attaining equilibrium. Either a Bourdon gage or pressure transducer can be used with this procedure. The interior surfaces of the liquid and vapor chambers are maintained free of water.

4. Significance and Use 4.1 Vapor pressure is an important physical property of liquid spark-ignition engine fuels. It provides an indication of how a fuel will perform under different operating conditions. For example, vapor pressure is a factor in determining whether a fuel will cause vapor lock at high ambient temperature or at high altitude, or will provide easy starting at low ambient temperature. 4.2 Petroleum product specifications generally include vapor pressure limits to ensure products of suitable volatility performance. NOTE 3mVapor pressure of fuels is regulated by various government agencies.

2. Referenced Documents 2.1 ASTM Standards:

5. Apparatus

D323 Test Method for Vapor Pressure of Petroleum Products (Reid Method) 2 D 4057 Practice for Manual Sampling of Petroleum and Petroleum Products a E 1 Specification for ASTM Thermometers 4.5

5.1 The apparatus for Procedure A is described in Annex AI. 5.2 The essential dimensions and requirements for the liquid and vapor chamber for Procedure B are identical with those for Procedure A and described in Annex A l. External fittings and features will vary depending on whether a gage or transducer is used and the provision for rotating the apparatus in the bath. Details of a commercially available unit are shown in Annex A2. 6

o

3. Summary of Test Method 3.1 The liquid chamber of the vapor pressure apparatus is filled with the chilled sample and connected to the vapor chamber at 37.8"C (100*F). The apparatus is immersed in a

6. Handling of Test Samples 6.1 This section applies to both Procedure A and B. 6.2 The extreme sensitivity of vapor pressure measurements to losses through evaporation is such as to require the

J This test method is under the jurisdiction of ASTM Committee 1)-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.08 on Volatility. Current edition approved Feb. 15, 1993. Published May 1993. Originally published as D 4953 - 89. Last previous edition D 4953 - 91. 2 Annual Book of ASTM Standards, Vol 05.01. 3 Annual Book of ASTM Standards, Vol 05.02. 4 Annual Book of ASTM Standards, Vol 05.03. Annual Book of ASTM Standards, Vol 14.03.

6 Vapor pressure apparatus meeting the requirements of Procedure B are available from UIC Inc., Joliet, IL; Walter Herzog GmbH, Lauda, Germany; or Precision Scientific, Chicago, IL.

771

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D 4953 chamber upright and not immersed over the top of the coupling threads.

utmost precaution and the most meticulous care in handling of samples. 6.3 Sampling shall be done in accordance with the Reid Vapor Pressure section (10.3) of Practice D 4057 except for fuels containing oxygenates where the Water Displacement Procedure section (10.3.1.8) of D 4057 must not be used. 6.4 Sample Container Size: 6.4.1 The size of the sample container from which the vapor pressure sample is taken shall be I L (1 qt). It shall be 70 to 80 % filled with sample. 6.4.2 The present precision statement has been derived using samples in I-L (l-qt) containers. Samples taken in containers of other sizes as prescribed in Practice D 4057 can be used if it is recognized that the precision can be affected. In the case of referee testing the I-L (l-qt) sample container shall be mandatory. 6.5 Hazard: 6.5.1 The vapor pressure determination shall be the first test withdrawn from the sample container. The remaining sample in the container cannot be used for a second vapor pressure determination. If necessary, obtain a new sample. 6.5.2 Samples shall be protected from excessive heat prior to testing. 6.5.3 Samples in leaky containers shall not be tested. Discard and obtain a new sample. 6.6 Sample Handling Temperature--In all cases, the sample container and contents shall be cooled to 0 to I*C (32 to 34"F) before the container is opened. Sufficient time to reach this temperature shall be assured by direct measurement of the temperature of a similar liquid in a like container placed in the cooling bath at the same time as the sample. See Annex AI.3.1.

NOTE 4: Caution--The transfer connection must be kept completely dry during cooling. This can be accomplished by placing the transfer connection in a water fight plastic bag. 7.5 Preparation of the Vapor Chamber 7.5. l Connect the gage or pressure transducer to the vapor chamber and make a water tight closure of the lower opening of the chamber where the liquid chamber attaches. Make sure that the vent hole in the vapor chamber connection is also securely closed. NOTE 5--For some Test Method D 323 apparatus, a Number 6.5 rubber stopper has been found satisfactory. For the horizontal or Herzogs apparatus, a Number 3 rubber stopper and a Number 000 cork in the vent hole is satisfactory. Another procedure is to attach a spare liquid chamber to the vapor chamber during the conditioning period. A third alternative is to utilize a cap threaded to match the threads of the vapor chamber. Several apparatus manufacturers have indicated the intention to supply such caps for equipment. In any procedure used, the interior surfaces of the vapor pressure apparatus and the sample must be kept completely free of water. NOTE 6: Caution--Making a water tight closure of both the liquid and vapor chambers is extremely important. For some samples containing oxygenated compounds, contact with water can cause phase separation and invalidate results. 7.5.2 Immerse the vapor chamber in a water bath maintained at 37.8 + 0. I*C (100 ± 0.2*F) for not less than 20 min. The top of the vapor chamber must be at least 25 mm (1 in.) below the surface of the water (Procedure A). (In Procedure B the vapor chamber lies horizontally, completely immersed in the water bath.) Do not remove the vapor chamber from the water bath until the liquid chamber has been filled with sample as described in 8.1.

8. Procedure 8.1 Sample Transfer--Remove the sample from the cooling bath, dry the exterior of the container with absorbent material, uncap, and insert the chilled transfer tube (see Fig. 1). Remove the liquid chamber from the cooling bath and, using an absorbent material, dry the threaded top and place the chamber in an inverted position over the top of the transfer tube. Invert the entire system rapidly so that the liquid chamber is upright with the end of the transfer tube approximately 6 mm (0.25 in.) from the bottom of the liquid chamber. Fill the chamber to overflowing. Withdraw the transfer tube from the liquid chamber while allowing the sample to continue flowing up to complete withdrawal. NOTE 7: Warning--Provision shall be mad~ 4"or suitable containment and disposal of the overflowingsample to avoid fire hazard.

7. Preparation of Apparatus 7.1 This section applies to both Procedure A and Procedure B. 7.2 Verification of Sample Container Filling--With the sample at a temperature of 0 to I*C (32 to 34"F), take the container from the cooling bath, wipe dry with absorbent material and unseal. Using a suitable gage, confirm that the sample volume equals 70 to 80 % of the container capacity. 7.2.1 Discard the sample if its volume is less than 70 % of the container capacity. 7.2.2 If the container is more than 80 % full, pour out enough sample to bring the container contents within 70 to 80 % range. Under no circumstance return any of the poured out sample to the container. 7.3 Air Saturation of Sample in Sample Container: 7.3. I With the sample again at a temperature of 0 to I*C (32 to 34"F), take the container from the cooling bath, open it momentarily, taking care that no water enters the sample, reseal it, and shake it vigorously. Return it to the bath for a minimum of 2 min. 7.3.2 Repeat 7.3.1 twice more. Return the sample to the cooling bath until the beginning of the procedure. 7.4 Preparation of Liquid Chamber: 7.4.1 Place the stoppered or closed liquid chamber and the sample transfer tube in a refrigerator or cooling bath for sufficient time to allow the chamber and the transfer tube to reach a temperature of 0 to I*C (32 to 34"F). Keep the liquid

8.2 Assembly of Apparatus--Immediately remove the vapor chamber from the water bath and, as quickly as possible, dry the exterior of the chamber with absorbent material with particular care given to the connection between the vapor chamber and the liquid chamber. Remove the closure from the vapor chamber and couple the filled liquid chamber to the vapor chamber as quickly as possible without spillage. When the vapor chamber is removed from the water bath and dried and the closure is removed, connect it to the liquid chamber without undue movement that could promote exchange of room temperature air with the 37.8"C (100*F) air in the chamber. Not more than 10 s should elapse 772

1]~ D 4953 Chilled Sample

(o)

(b)

(c}

Sample Container SeahngCloser GasolineChamber Prior to Transfer Replacedby Sample PlacedOver liquid of Sample TransferConnection DeliveryTube FIG. 1

of not less than 2 min, tap the gage, observe the reading and repeat the instructions given in 8.3 until a total of not less than five shakings and gage readings have been made and continuing thereafter if necessary until the last two consecutive gage readings are constant, indicating that equilibrium has been attained. Read the final gage pressure to the nearest 0.25 kPa (0.05 psi) and record this value as the uncorrected vapor pressure of the sample. Without undue delay remove the pressure gage from the apparatus and, without attempting to remove any liquid that may be trapped in the gage, check its reading against that of the manometer while both are subjected to a common steady pressure that is not more than 1.0 kPa (0.2 psi) from the recorded uncorrected vapor pressure. If a difference is observed between the gage and the manometer readings, add to or subtract the difference from the uncorrected vapor pressure and record the resulting value as the vapor pressure of the sample. 8.5.2 Procedure B--After the assembled apparatus has been in the bath for at least 5 rain, tap the pressure gage lightly and observe the reading. Repeat the tapping and reading at intervals of not less than 2 min, until 2 consecutive readings are constant. (Tapping is not necessary with transducer model but the reading intervals are the same.) Read the final gage or transducer pressure to the nearest 0.25 kPa (0.05 psi) and record this value as the uncorrected vapor pressure. Without undue delay, disconnect the gage or pressure transducer from the apparatus and check its reading against that of the manometer while both are subjected to a common steady pressure that is not more than 1.0 kPa (0.2 psi) different from the recorded uncorrected vapor pressure. If a difference is observed between the gage or transducer and the manometer, add to or subtract the difference from the uncorrected vapor pressure and record the resulting value as the vapor pressure of the sample.

Chilled Liquid Chamber

(d) Positionof Systemfor Sample Transfer

Simplified Sketches Outlining Method Transferring Sample to Liquid Chamber from Open-Type Containers

between removing the vapor chamber from the water bath and completion of the coupling of the two chambers. With Procedure B it is necessary to disconnect the spiral tubing at the quick action disconnect after removing from the water bath and before making the connection to the vapor chamber. 8.3 Introduction of the Apparatus into Bath: 8.3.1 ProcedureA - - T u r n the assembled apparatus upside down and allow all the sample in the liquid chamber to drain into the vapor chamber. With the apparatus still inverted, shake it vigorously eight times lengthwise. With the gage end up, immerse the assembled apparatus in the bath, maintained at 37.8 __. 0. I*C (100 __. 0.2°F), in an inclined position so that the connection of the liquid and vapor chambers is below the water level. Carefully examine for leaks. If no leaks are observed, further immerse the apparatus to at least 25 mm (1 in.) above the top of the vapor chamber. Observe the apparatus for leaks throughout the test and discard the test at anytime a leak is detected. 8.3.2 Procedure BwWhile holding the apparatus in a vertical position immediately reconnect the spiral tubing at the quick action disconnect. Tilt the apparatus to 20 to 30* downward for 4 or 5 s to allow the sample to flow into the vapor chamber without getting into the tube extending into the vapor chamber from the gage or pressure transducer. Place the assembled apparatus into the water bath maintained at 38.7 + 0.1*C (100 __. 0.2*F) in such a way that the bottom of the liquid chamber engages the drive coupling and the other end of the apparatus rests on the support bearing. Observe the apparatus for leakage throughout the test. Discard the test anytime a leak is detected. 8.4 After the apparatus has been immersed in the bath, check the remaining sample for phase separation. If the sample is contained in a glass container, this observation can be made prior to sample transfer (8.1). If the sample is contained in a non-transparent container, mix the sample thoroughly and immediately pour a portion of the remaining sample into a clear glass container and observe for evidence of phase separation. If the sample is not clear and bright or if a second phase is observed, discard the test and the sample. 8.5 Measurementof Vapor Pressure: 8.5.1 Procedure A n A f t e r the assembled apparatus has been in the water bath for at least 5 min, tap the pressure gage lightly and observe the reading. Withdraw the apparatus from the bath and repeat the instructions of 8.3. At intervals

NOTE 8--If it is suspected that phase separation of the sample may have occurred during the test procedure, the followingprocedure can be performed to verify the integrity of the test sample. Perform the followingoperations as quickly as possible after removing the apparatus from the water bath in order to maintain the temperature of the sample at or near the test temperature. Quickly dry the exterior surfaces of the liquid and vapor chambers with absorbent material. With the apparatus in an upright position, disconnect the vapor and liquid chambers. Quickly drain the contents of the liquid chamber into a dry, clear, glass container and observe the sample. If the sample is not clear and brigllt and free of a second phase, cap the container, reheat the sample to 37.8"C (IO0*F), mix the sample well, and observe the sample again. If the sample is still not clear and bright and free of a second phase, phase separation has occurred and the test may not be valid. 8.6 Preparation of Apparatus for Next TestmThoroughly purge the vapor chamber of residual sample by filling it with warm water above 32"C (90*F) and allowing it to drain. Repeat this purging at least five times. Purge the liquid chamber in the same manner. Rinse both chambers and the transfer tube several times with petroleum naphtha, then several times with acetone, then blow dry using dried air. Appropriately close the liquid chamber and place it in the cooling bath or refrigerator in preparation for the next test. Use an appropriate closure for the bottom connection (where liquid chamber attaches) of the vapor chamber and attach the gage after the gage has been prepared in accordance with 8.6.2. 8.6.1 If the purging of the vapor chamber is done in a 773

D 4953 10.1.2 Reproducibility--The difference between two single and independent test results obtained by different operators working in different laboratories on identical test material would, in the long run, in the normal and correct operation of the test method, exceed the following values only in one case in twenty: Procedure A 5.52 kPa (0.80 psi) Procedure B (See Note 10) Gage (See Note 11) 5.38 kPa (0.78 psi) Transducer (Herzog)6 2.90 kPa (0.42 psi) Transducer (Precision Scientific)6 4.27 kPa (0.62 psi)

bath, be sure to avoid small films of floating sample by keeping the bottom and top openings of the chamber closed as they pass through the water surface. 8.6.2 Preparation ofGage--Procedure AmDisconnect the gage from its manifold connection with the manometer, remove trapped liquid in the Bourdon tube of the gage by repeated centrifugal thrusts. Accomplish this in the following manner: hold the gage between the palms of the hands with the right palm on the face of the gage and the threaded connection of the gage forward, extend the arms forward and upward at an angle of 45*, and swing the arms rapidly downward through an arc of about 135" so that centrifugal force aids gravity in removing trapped liquid. Repeat this operation at least 3 times or until all liquid has been expelled from the gage. Connect the gage to the vapor chamber with the liquid connection closed and place in the 37.8"C (100*F) bath to condition for the next test. 8.6.3 Preparation of Gage or Transducer--Procedure B In the correct operation of Procedure B liquid does not reach the gage or transducer. If it is observed or suspected that liquid has reached the gage, purge the gage as described in 8.6.2. The transducer has no cavity to trap liquid. Ensure that no liquid is present in the T-handle fitting or spiral tubing by forcing a stream of dry air through the tubing. Connect the gage or transducer to the vapor chamber with the liquid connection closed and place in the 37.8"C (100*F) bath to condition for the next test.

NOTE 10--The data from the three instruments that performed Procedure B, in the interlaboratory program described in Note 9 yielded precision figures that are different statistically and could not be pooled. Hence these figures are displayed individually. NOTE I I--The precision figures are applicable only to gages manufactured by Armaturenbau, GMBH,6 0 to 15 psi, Bourdon tube volume of 38 mL nominal. Usage of gauges with other internal volumes may affect the test method precision and bias. 10.2 Bias: 10.2.1 Absolute Bias--Since there is no accepted reference material suitable for determining the bias for the procedures in this test method for measuring vapor pressure of gasoline or gasoline-oxygenate blends, bias cannot be determined. The amount of bias between this test vapor pressure and true vapor pressure is unknown. 10.2.2 Relative Bias--Statistically significant relative biases between Procedures A and Procedure B were observed in the data from the cooperative program described in Note 9. These biases can be corrected by applying the appropriate correlation equation listed below, that calculates a dry vapor pressure equivalent value for Procedure A (DVPE, Procedure A), from values obtained by Procedure B: 10.2.2.1 For Procedure B, gage See Note 10: DVPE, Procedure A = 1.029 X (l)

9. Report

9.1 Reporting Results--Report the vapor pressure to the nearest 0.25 kPa (0.05 psi) in kilopascals (pounds-force per square inch) without reference to temperature. 10. Precision and Bias 7

10.1 The following criteria are to be used for judging the acceptability of results.

10.2.2.2 For Procedure B, transducer, Herzog equipment: DVPE, Procedure A = 0.984 X

NOTE 9--The following precision data were developed in a 1991 interlaboratory cooperative test program. Participants analyzed sample sets comprised of blind duplicates of 14 types of hydrocarbons and hydrocarbonoxygenate blends. The oxygen content ranged from 0 to 15 % by volume nominal and the vapor pressure ranged from 14 to 100 kPa (2 to 15 psi) nominal. A total of 60 laboratories participated. Some participants performed more than one test method, using separate sample sets for each. Twenty-six samples sets were tested by Test Method D 4953, 13 by Test Method D 5190 and 27 by Test Method D5191. In addition, six sets were tested by modified Test Method D 5190 and 13 by modified Test Method D 5191.

(2)

where: X = observed total vapor pressure from Procedure B 10.2.3 No relative bias was observed between procedure A and the Precision Scientific equipment in the data obtained in the interlaboratory program described in Note 9. 10.2.4 Since Test Method D 323 was not included in the 1991 interlaboratory test program described in Note 9, no statement can be made regarding the relative bias between any of the methods studied versus Test Method D 323 based on data from this study. However, from a 1987 interlaboratory study g, no statistically significant bias was observed between Procedure A of this test method and Test Method D 323 for samples containing hydrocarbons only or hydrocarbons and methyl t-butyl ether.

10.1. l Repeatability--The difference between successive test results obtained by the same operator with the same apparatus under constant operating conditions on identical test material would, in the long run, in the normal and correct operation of the test method, exceed the following values in only one case in twenty: Procedure A 3.65 kPa (0.53 psi) Procedure B (See Note 10) Gage (See Note II) 4.00 kPa (0.58 psi) Transducer (Herzog)6 2.14 kPa (0.31 psi) Transducer (Precision Scientific)6 3.58 kPa (0.52 psi)

NOTE 12--In the 1991 interlaboratory test program described in Note 9, one jet fuel of type JP-4 was included. Statistically lower repeatability and reproducibility estimates for Procedure B were observed for this particular sample compared to all others in the sample set. Since only one jet fuel was tested in the program, these figures are

The results of this test program are filed at ASTM Headquarters. Request RR: I)02-1286.

s The results of the cooperative test program from which these values have been derived are filed at ASTM Headquarters. Request RR:D02-1245.

774

4t~ O 4953 r ~ 3.6 kPa (0.52 psi) Procedure A r = = 0.69 kPa (0.10 psi) Procedure B (gage) r ~ 1.3 kPa (0.19 psi) Procedure B (TransducerHerzo~g, Precision Scientific)6

not intended nor can it be technically considered as a precision statement regarding usage of this method on all jet fuels. This is provided as information only for those who are interestred in the approximate precision of this method when applied to a jet fuel of type JP-4.

R = 5.0 kPa (0.73 psi) R = 2.3 kPa (0.33 psi) R = 2.3 kPa (0.33 psi)

ANNEX

(Mandatory Information) AI. A P P A R A T U S FOR V A P O R P R E S S U R E T E S T P R O C E D U R E A

A 1.1 VaporPressureApparatus, consisting of 2 chambers, a vapor chamber (upper section) and a liquid chamber (lower section), shall conform to the requirements in this annex.

an internal diameter of not less than 4.8 m m (¥~6 in.) shall be provided to receive the 6.35 m m (1/4 in.) gage connection. In the other end an opening approximately 12.7 m m (I/2 in.) in diameter shall be provided for coupling with the liquid chamber. The connections to the openings shall not prevent the chamber from draining completely. A I.I.2 Liquid Chamber--The lower section or liquid chamber, as shown in Fig. A I. 1, shall be a cylindrical vessel of the same internal diameter as the vapor chamber and of such a volume that the ratio of the volume of the vapor chamber to the volume of the liquid chamber shall be between 3.8 and 4.2. In one end of the liquid chamber an opening of approximately 12.7 m m (t/2 in.) in diameter shall be provided for coupling with the vapor chamber. The inner surface of the coupling end shall be sloped to provide complete drainage when inverted. The other end of the chamber shall be completely closed. A l . I . 3 Method of Coupling Vapor and Liquid Chambers-Any method of coupling the vapor and liquid chambers can be employed, provided that no sample is lost from the liquid chamber during the coupling operation, that no compression effect is caused by the act of coupling, and that the assembly is free of leaks under the conditions of the tests. To avoid displacement of sample during assembly, the male fitting of the coupling must be on the liqtfid chamber. To avoid compression of air during assembly aivent hole must be present to ensure atmospheric pressur~ in the vapor chamber at the instant of sealing.

NOTE A I. 1 Caution--To maintain the correct volume ratio between the vapor chamber and the liquid chamber, the units shall not be interchanged without recalibration to ascertain that the volume ratio is within the required limits. A1.1.1 VaporChamber--The upper section of the vapor chamber, as shown in Fig. A 1.1, shall be a cylindrical vessel having the inside dimensions of 51 ___ 3 m m (2 + l/s in.) in diameter and 254 _ 3 m m (10 __. I/s in.) in length, with the inner surfaces of the ends slightly sloped to provide complete drainage from either end when held in a vertical position. On one end of the vapor chamber, a suitable gage coupling with

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NOTE AI.2 Caution--Some commercially avai,lable apparatus do not make adequate provision for avoiding air compression effects. Before employing any apparatus, it shall be established that the act of coupling the two chambers does not compress air in the vapor chamber. This can be accomplished by tightly stoppering the liquid chamber and coupling the apparatus in the normal manner, utilizing a 0 to 35 kPa (0 to 5 psi) gage. Any observable pressure increase on the gage is an indication that the apparatus does not adequately meet the specifications of the test method. If this problem is encountered, consult the manufacturer.

GasohneChamber (OneOpening)

DIMENSIONSOF VAPORPRESSUREAPPARATUS Description mm in. Vaporchamber,length 254 ± 3 10 ± 1/e Vaporand gasolinecham51 ± 3 2 :t: '/e bets, LiquidID Coupling,ID min 4.7 z/le Coupling,OD 12.7 1/= Coupling,ID 12.7 1/e Valve 12.7 1/= Valve 6.35 1/4 FIG. A1.1

A 1.1.4 VolumetricCapacity of Vapor and Liquid Chambers-To ascertain if the volume ratio of the chambers is within the specified limits of 3.8 to 4.2, carefully measure a quantity of water greater than will be required to fill the 2 chambers. (A dispensing buret is a convenient vessel for this operation.) Without spillage, fill the liquid chamber completely. The difference between the original volume and the remaining volume is the volume of the liquid chamber. Without spillage, couple the liquid and vapor chambers and

Vapor Pressure Apparatus

775

~

D 4953

fill the vapor chamber to the seat of the gage connection with more ofthe measured water. The difference in volumes is the volume of the vapor chamber. Calculate the volume ratio as follows: vapor chamber volume liquid chamber volume = volume ratio A I.2 Pressure Gage--The pressure gage shall be a Bourdon type spring gage of test gage quality 100 to 150 mm (4.5 to 5.5 in.) in diameter provided with a nominal 6.35 mm (0.25 in.) male thread connection with a passageway not less than 4.7 mm (3/16 in.) in diameter from the Bourdon tube to the atmosphere. The gage range shall be 0 to 100 kPa (0 to 15 psi) with intermediate graduations at 0.5 kPa (0. l psi). Only accurate gages shall be continued in use. When the gage reading differs from the manometer reading by more than 1.0 kPa (0.15 psi), discontinue use of the gage. A 1.3 Cooling Bath: A I.3. l A suitable cooling bath shall be provided of such dimensions that the sample containers and the liquid cham-

bets can be completely immersed. Either a water or air bath is acceptable. A means of maintaining the bath at a temperature of 0 to l°C (32 to 340F) must be provided. A1.3.2 Solid carbon dioxide shall not be used to cool samples in storage or in the cooling bath of A 1.3. I. AI.4 Water Bath--The water bath shall be of such dimensions that the vapor pressure apparatus can be immersed to at least 25.4 mm (l in.) above the top ofthe vapor chamber. Means for maintaining the bath at a constant temperature of 37.8 + 0.1°C (100 _+0.2°F) shall be provided. In order to check this temperature the bath thermometer shall be immersed to the 37°C (98°F) mark throughout the vapor pressure determination. AI.5 Thermometer--An ASTM Reid Vapor Pressure thermometer 18C (l 8F) having a range from 34 to 42°C (94 to 108°F) and conforming to the requirements in Specification E l shall be used in the water bath of Annex A I.4. A1.6 Mercury Manometer--A mercury manometer having a range suitable for checking the pressure gage shall be used. The manometer scale shall be graduated in steps of 0.5 kPa, l ram, 0.1 in., or 0.1 psi.

A2. APPARATUS FOR VAPOR PRESSURE TEST PROCEDURE B A2.1 Vapor Pressure Apparatus--Refer to Annexes A 1.1 through A I. 1.4. A2.2 Pressure Gage--The pressure measuring system shall be a Bourdon type spring gage as described in Annex A I.2 or a suitable pressure transducer and digital readout. The pressure measuring system shall be remotely mounted from the vapor pressure apparatus and terminations provided for use of a quick connection type fitting. A2.3 Cooling Bath--Refer to Annex A 1.3. A2.4 Water Bath--The water bath shall be of such dimensions that the vapor pressure apparatus can be immersed in a horizontal position. Provision shall be made to rotate the apparatus on its axis 350 ° in one direction and then 350 ° in the opposite direction in repetitive fashion. Means for maintaining the bath at a constant temperature of 37.8 _+ 0.1°C (100 _+ 0.2°F) shall be provided. In order to check this temperature, the bath thermometer shall be immersed to the 37°C (980F) mark throughout the vapor pressure determination. A suitable bath is shown in Fig. A2. l and is available commercially. A2.5 Thermometers--Refer to Annex A1.5. A2.6 Mercury Manometer--Refer to Annex A 1.6. A2.7 Flexible Coupler--A suitable flexible coupling shall be provided for connection of the rotating vapor pressure apparatus to the pressure measuring device. A2.8 Vapor Chamber Tube--The vapor chamber tube of inner diameter 3 mm (I/a in.) and length of 114 mm (4.5 in.) shall be inserted into the pressure measuring end of the vapor chamber to prevent liquid from entering the vapor pressure measuring connections.

776

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Apparatus for Vapor Pressure, Procedure B

(~ D 4953 The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at • meeting of the responsible technical committee, which you may attend, ff you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103.

777

{~

Designation:D 5002 - 94

An American National Standard

Standard Test Method for Density and Relative Density of Crude Oils by Digital Density Analyzer I This standard is issued under the fixed designation D 5002; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (O indicates an editorial change since the last revision or reapproval.

3. Terminology 3.1 Definitions: 3.1.1. densitymmass per unit volume at a specified temperature. 3.1.2 relative densityDthe ratio of the density of a material at a stated temperature to the density of water at a stated temperature.

1. Scope 1.1 This test method covers the determination of the density or relative density of crude oils that can be handled in a normal fashion as liquids at test temperatures between 15 and 35°C. This test method applies to crude oils with high vapor pressures provided appropriate precautions are taken to prevent vapor loss during transfer of the sample to the density analyzer. 1.2 This test method was evaluated in round robin testing using crude oils in the 0.75 to 0.95 g/mL range. Lighter crude oil can require special handling to prevent vapor losses. Heavier crudes can require measurements at higher temperatures to eliminate air bubbles in the sample. 1.3 The accepted units of measurement of density are grams per millilitre and kilograms per cubic metre. 1.4 This standard does not purport to address all of the

4. Summary of Test Method 4.1 Approximately 0.7 mL of crude oil sample is introduced into an oscillating sample tube and the change in oscillating frequency caused by the change in the mass of the tube is used in conjunction with calibration data to determine the density of the sample. 5. Significance and Use 5.1 Density is a fundamental physical property that can be used in conjunction with other properties to characterize the quality of crude oils. 5.2 The density or relative density of crude oils is used for the conversion of measured volumes to volumes at the standard temperatures of 15"C or 60*F and for the conversion of crude mass measurements into volume units. 5.3 The application of the density result obtained from this test method, for fiscal or custody transfer accounting calculations, can require measurements of the water and sediment contents obtained on similar specimens of the crude oil parcel.

safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Specific hazard statements are given in Notes l, 2, and 3.

2. Referenced Documents 2.1 A S T M Standards: D941 Test Method for Density and Relative Density (Specific Gravity) of Liquids by Lipkin Bicapillary Pycnometer2 D 1193 Specification for Reagent Water3 D 1217 Test Method for Density and Relative Density (Specific Gravity) of Liquids by Bingham Pycnometer2 D 1250 Guide for Petroleum Measurement Tables 2 D 4052 Test Method for Density and Relative Density of Liquids by Digital Density Meter4 D4057 Practice for Manual Sampling of Petroleum and Petroleum Products4 D 4177 Practice for Automatic Sampling of Petroleum and Petroleum Products4 D4377 Test Method for Water in Crude Oils by Volumetric Karl Fischer Titration4

6. Apparatus 6.1 Digital Density Analyzer--A digital analyzer consisting of a U-shaped, oscillating sample tube and a system for electronic excitation, frequency counting, and display. The analyzer must accommodate the accurate measurement of the sample temperature during measurement or must control the sample temperature as described in 6.2 and 6.5. The instrument shall be capable of meeting the precision requirements described in Test Method D 4052. 6.2 Circulating Constant-Temperature Bath, capable of maintaining the temperature of the circulating liquid constant to +0.05"C in the desired range. Temperature control can be maintained as part of the density analyzer instrument package. 6.3 Syringes, at least 2 mL in volume with a tip or an adapter tip that will fit the inlet of the density analyzer. 6.4 Flow-Through or Pressure Adapter, for use as an alternative means of introducing the sample into the density meter. 6.5 Thermometer, calibrated and graduated to 0. I'C, and

l This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.04.OD on Physical MethtJds. Current edition approved July 15, 1994. Published September 1994. Originally published as D 5002 - 89. Last previous edition D 5002 - 89. 2 Annual Book of ASTM Standards, Vol 05.01. Annual Book of ASTM Standards, Vol I 1.01. 4 Annual Book of ASTM Standards, Vol 05.02.

778

o s002 a thermometer holder that can be attached to the instrument for setting and observing the test temperature. In calibrating the thermometer, the ice point and bore corrections should be estimated to the nearest 0.05"C. Precise setting and control of the test temperature in the sample tube is extremely important. An error of 0.1*C can result in a change in density of one in the fourth significant figure.

7. Reagents and Materials

7.1 Purity of Reagents--Reagent grade chemicals shall be used in all tests. Unless otherwise indicated it is intended that all reagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, where such specifications are available. 5 Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination. 7.2 Purity of Water--Unless otherwise indicated, references to water shall be understood to mean reagent water as defined by Type II of Specification D 1193. 7.3 Water, redistilled, freshly boiled and cooled reagent water for use as a primary calibration standard. 7.4 Acetone, for flushing and drying the sample tube.

D 4377. Mixing at room temperature in an open container can result in the loss of light ends, so mixing in closed, pressurized containers or at sub-ambient temperatures is recommended. 8.3.2 Draw the test specimen from a properly mixed laboratory sample using an appropriate syringe. Alternatively, if the proper density analyzer attachments and connecting tubes are used then the test specimen can be delivered directly to the analyzer's sample tube from the mixing container.

9. Preparation of Apparatus 9.1 Set up the density analyzer and constant temperature bath following the manufacturer's instructions. Adjust the bath or internal temperature control so that the desired test temperature is established and maintained in the sample compartment of the analyzer. Calibrate the instrument at the same temperature at which the density of the sample is to be measured. 10. Calibration of Apparatus 10.1 Calibrate the instrument when first setting up and whenever the test temperature is changed. Thereafter, conduct calibration checks at least weekly during routine operation or more frequently as may be dictated by the nature of the crude oils being measured, (see 10.3). 10.2 Initial calibration, or calibration after a change in test temperature, necessitates calculation of the values of the Constants A and B from the periods of oscillation, (7), observed when the sample cell contains certified reference liquids such as air and double-distilled boiled water. Other calibrating materials such as n=nonane, n-tridecane, cyclohexane, and n-hexadecane (for high temperature applications) can also be used as appropriate. 10.2.1 While monitoring the oscillator period, T, flush the sample tube with petroleum naphtha, followed .with an acetone flush and dry with dry air. Continue drying until the display exhibits a steady reading. In cases where saline components can be deposited in the cell, flush with distilled water followed by acetone and dry air. Contaminated or humid air can affect the calibration. When these conditions exist in the laboratory, pass the air used for calibration through a suitable purification and drying train. In addition, the inlet and outlet ports for the U-tube must be plugged during measurement of the calibration air to prevent ingress of moist air. 10.2.2 Allow the dry air in the U-tube to come to thermal equilibrium with the test temperature and record the T-value for air. 10.2.3 Introduce about 0.7 mL of freshly boiled and cooled double-distilled water into the sample tube from the bottom opening using a suitable syringe. The water must be free of even the smallest air or gas bubbles. The sample tube shall be completely full. Allow the water to reach thermal equilibrium at the test temperature and record the T-value for water and the test temperature. 10.2.4 Alternatively introduce one of the hydrocarbon calibration standards and measure the T-value as in 10.2.3. 10.2.5 Calculate the density of air at the temperature of test using the following equation: da 0.001293[273/7"][1)/760]g/mL (1)

NOTE 1: Warning--Extremely flammable.

7.5 Petroleum Naphtha,6 for flushing viscous petroleum samples from the sample tube. NOTE 2: Warning--Extremely flammable.

7.6 n-Nonane, n-tridecane or cyclohexane, 99 % purity or better, or similar pure material for which the density is known precisely from literature references or by direct determination in accordance with Test Method D 941 or D 1217. NOTE 3: Warnlng--Extremely flammable.

8. Sampling, Test Specimens, and Test Units 8.1 Sampling is defined as all the steps required to obtain an aliquot of the contents of any pipe, tank or other system, and to place the sample into the laboratory test container. The laboratory test container and sample volume shall be of sufficient dimensions to allow mixing as described in 8.3.1. Mixing is required to obtain a homogeneous sample for analysis. 8.2 Laboratory Sample--Use only representative samples obtained as specified in Practices D 4057 or D 4177 for this test method. 8.3 Test Specimen--The aliquot of sample obtained from the laboratory sample and delivered to the density analyzer sample tube. The test specimen is obtained as follows: 8.3.1 Mix the sample of crude oil to homogenize any sediment and water present. The mixing may be accomplished as described in Practice D4177 or Test Method s Reagent Chemicals, American Chemical Society Specifications, American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed by the American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville, MD. 6 Suitable solvent naphthas are marketed under various designations such as "petroleum ether," "ligroine," or "precipitation naphtha."

=

779

~

D 5002 A recognized carcinogen.) whenever a major adjustment is required. Chromic acid solution is the most effectivecleaning agent; however, surfactant-typecleaning fluids have also been used successfully.

TABLE 1 Density of Water* (in vacuo) Temperatun), *C 0,0 3.0 4.0 5.0 10.0 15,0 15.56 16.0 17.0 18.0 19.0 20.0

Density g/mL 0.999840 0.999964 0,999964 0,999964 0.999699 0.999099 0.999012 0.998943 0.998774 0.998595 0.996404 0,998203

Temperatun), *C 21.0 22.0 23.0 24.0 25.0 26.0 27.0 28.0 29.0 30.0 35.0 37,78

Density g/mL 0.997991 0.997769 0.997537 0.997295 0.997043 0.996782 0.996511 0.996231 0.995943 0.995645 0.994029 0.993042

Temperatun), *C

Density g/mL

40.0 45.0 50.0 55.0 60.0 65,0 70.0 75,0 80.0 85.0 90.0 100.0

0.992212 0.990208 0.988030 0.985688 0.983191 0.980546 0.977759 0.974837 0.971785 0.968606 0.965305 0.958345

10.3.1 Flush and dry the sample tube as described in 10.2.1 and allow the display to reach a steady reading. If the display does not exhibit the correct T-value or density for air at the temperature of test, repeat the cleaning procedure or adjust the value of Constant B commencing with the last decimal place until the correct density is displayed. 10.3.2 If adjustment to Constant B was necessary in 10.3.1 .then continue the recalibration by introducing freshly boiled and cooled double-distilled water into the sample tube as described in 10.2.3 and allowing the display to reach a steady reading. If the instrument has been calibrated to display the density, adjust the reading to the correct value for water at the test temperature, (see Table 1) by changing the value of Constant A, commencing with the last decimal place. If the instrument has been calibrated to display the relative density, adjust the reading to the value 1.0000.

A Densities conforming to the Intemational Temperature Scale 1990 (ITS 90) were extracted from Appendix G, Standard Methods for Analysis of Petroleum and Related Products 1991, Institute of Petroleum, London.

where: T -- temperature, K, and P -- barometric pressure, ton'. 10.2.6 Determine the density of water at the temperature of test by reference to Table I. 10.2.7 Alternatively record the density at the test temperature for the hydrocarbon calibrant used in 10.2.4 as obtained from an appropriate reference source or from direct determination (see 7.6). 10.2.8 Using the observed T-values and the reference values for water and air, calculate the values of the Constants A and B using the following equations: A = [ T ~ 2 - T a 2 ] / [ d ~ - da] (2) B = T~ 2 - (A x do)

NOTE 5rain applying this periodic calibration procedure, it has been

found that more than one value each for A and B, differingin the fourth decimal place, will yield the correct reading for the density of air and water. The setting chosen would then be dependent upon whetherit was approached from a higher or lower value. The setting selected by this method could have the effect of altering the fourth place of the reading obtained for a sample. 10.4 Some analyzer models are designed to display the measured period of oscillation only (T-values) and their calibration requires the determination of an instrument constant K, that must be used to calculate the density or relative density from the observed data. Use the procedure in 10.4.1, 10.4.2 and 10.4.3 in this case. 10.4.1 Flush and dry the sample tube as described in 10.2.1 and allow the air to reach equilibrium at the test temperature and the readout to display a steady value. Record the T-value for air. 10.4.2 Introduce freshly boiled and cooled double-distilled water into the sample tube as described in 10.2.3, allow the display to reach a steady reading and record the T-value for water. 10.4.3 Using the observed T-values and the reference values for water and air (10.2.5 and 10.2.6), calculate the instrument constant, K, using the following equations: for density:

(3)

where: T~ = observed period of oscillation for cell containing water, T a = observed period of oscillation for cell containing air, dw = density of water at test temperature, and do = density of air at test temperature. Alternatively, use the T and d values for the other reference liquid if one is used. 10.2.9 If the instrument is equipped to calculate density from the Constants A and B and the observed T-value from the sample, then enter the constants in the instrument memory in accordance with the manufacturer's instructions. 10.2.10 Check the calibration and adjust if needed by performing the routine calibration check described in 10.3. 10.2.11 To calibrate the instrument to determine relative density, that is, the density of the sample at a given temperature referred to the density of water at the same temperature, follow 10.2.1 through 10.2.9, but substitute 1.000 for d~ in performing the calculations described in 10.2.8. 10.3 Since some crude oils can be difficult to remove from the sample tube, frequent calibration checks are recommended. These checks and any subsequent adjustments to Constants A and B can be made if required, without repeating the calculation procedure.

KI = [dw - da]/[Tw 2 - Ta 2]

(4)

for relative density: K 2 = [1.0000 - da]/[Tw 2 - Ta 2]

(5)

where: Tw = observed period of oscillation for cell containing water, Ta = observed period of oscillation for cell containing air, dw -- density of water at test temperature, and da = density of air at test temperature. 11. P r o c e d u r e I l.l Introduce about 0.7 mL of crude oil into the clean, dry, sample tube of the instrument using a suitable syringe. Leave the syringe in place and plug the exit port. l l.2 Turn on the illumination light and examine the sample tube carefully. Make sure that there is no obvious

NOTE 4raThe need for a change in calibration is generally attributable to deposits in the sample tube that are not removed by the routine flushingprocedure. Although this condition can be compensated for by adjusting A and B, as described below, it is good practice to clean the tube with warm chromic acid solution (Warning--Causes severe bums.

780

~1~ D 5002 TABLE 2

presence of bubbles trapped in the U-tube, and that it is filled completely. The sample must appear to be homogeneous. Turn the illumination light off immediately after inspection of the sample tube, since the heat generated affects the measurement temperature. I 1.3 Allow the sample to equilibrate to the test temperature before proceeding to evaluate the test sample for the presence of unseen air or gas bubbles. I 1.4 For dark crude oil samples the observation of air or gas bubbles in the sample tube is very difficult. The presence of bubbles can often be detected, however, by observing the fluctuations of the digital display of the T-value or density value. Air or gas bubbles cause large random variations in the third and fourth significant figures for density reading and fifth and sixth significant figures for T readings. When bubbles are absent and the sample is at equilibrium with the test temperature, the displayed values are stable, do not drift, and show only small variations of the order of + l to 2 units in the last significant figure. If stable values are not observed after a few minutes, then repeat the injection of a new sample into the tube.

Repeatal~ility

Reproducibility

0.70 0.75 0.80 0.85 0.90 0.95

0.0007 0.0008 0.0008 0.0009 0.0009 0.0010

0.0029 0.0031 0.0033 0.0035 0.0037 0.0039

another temperature, Guide D 1250 can be used only if the table values have not been corrected for the glass expansion factor. 13. Report 13.1 In reporting density, give the test temperature and the units, (for example: density at 20"C = 0.8765 g/mL or 876.5 kg/m 3 (in vacuo)). 13.2 In reporting relative density, give both the test temperature and the reference temperature, but no units, (for example: relative density, 15/15"C = x.xxxx). 13.3 Report the final result to four significant figures.

NOTE 6 m W h e n viscous liquids are being measured, a stable reading can be achieved even when air or gas bubbles are present. Careful

14. Precision and Bias 7,a 14.1 The precision of this test method as obtained by statistical examination of interlaboratory test results at test temperatures of 15 and 20"C is as follows: 14.1.1 Repeatability--The difference between successive test results obtained by the same operator with the same apparatus under constant operating conditions on identical test material, would in the long run, in the normal and correct operation of this test method, exceed the following value only in one case in twenty, (see Table 2):

injection of fresh sample will often eliminate bubbles. Since bubbles contribute to lower density readings,an observed increase in the density of the liquid after injection of fresh sample tends to suggestthat bubbles were previouslypresent. I 1.5 After the instrument displays a steady reading to four significant figures for density and five for T-values, indicating that temperature equilibrium has been reached, record the density or T-value. 11.6 Flush and dry the sample tube as described in 10.2.1 and check the calibration as described in 10.3.1 prior to introducing another sample.

range

repeatability

0.75 to 0.95

0.00105X

where: X - sample mean.

12. Calculation 12.1 Calculating Density Analyzers--The recorded value is the final result, expressed either as density in g/mL, kg/m 3 or as relative density. Note that kg/m 3 = 1000 x g/mL. I2.2 Noncalculating Density Analyzers--Using the observed T-value for the sample and the T-value for water and appropriate instrument constants determined in 10.4.3, calculate the density or relative density using Eqs 6 and 7. Carry out all calculations to six significant figures and round the final results to four. Note that kg/m 3 = 1000 x g/mL.

14.1.2 Reproducibility--The difference between two single and independent results, obtained by different operators working in different laboratories on identical test material, would in the long run, in the normal and correct operation of the test method, exceed the following values only in one case in twenty, (see Table 2): range

reproducibility

0.75 to 0.95

0.004123(

where: X --- sample mean. 14.2 Bias--No significant bias was observed between the known density value for reference materials and the values determined in interlaboratory testing. The accuracy of results shall not differ from the established true value by more than the stated precision.

for density: density, g/mL at t -- d w + Kl(Ts2 - Tw2)

Precision Values

Density

(6)

for relative density: relative density, t/t -- 1 + K2(Ts2 - Tw2) (7) where: Tw= observed period of oscillation for cell containing water, = observed period of oscillation for cell containing sample, dw :== density of water at test temperature, K z = instrument constant for density, ~= instrument constant for relative density, and t = temperature of test *C. 12.3 If it is necessary to convert a result obtained using the density analyzer to a density or relative density at

15. Keywords 15.1 density, relative density, digital density analyzer, crude oils Supporting data are available from ASTM Headquarters, Request RR:D021257. s Biased results for high viscosity samples (>ca. 100 mPa-s dynamic viscosity) has been reported in the literature. For additional information, consult the Journal of Physical Chemistry, Vol 84, 1980, pp. 158-162 and the Journal of the Chemical Society Faraday Translation, Vol 86 (I), 1990, pp. 145-149.

781

fl~ D 5002 The American Society for Testing end Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, end the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and ff not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend, ff you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103.

782

q~l~ Designation: D 5060 - 95

Standard Test Method for Determining Impurities in High-Purity Ethylbenzene by Gas Chromatography I This standard is issued under the fixed designation D 5060; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (0 indicates an editorial change since the last revision or reapproval.

1. Scope 1.1 This test method describes the analysis of normally occurring impurities in, and the purity of, ethylbenzene by gas chromatography. Impurities determined include nonaromatic hydrocarbons, benzene, toluene, xylenes, cumene, and diethylbenzene isomers. 1.2 This test method is applicable for impurities at concentrations from 0.001 to 1.000 % and for ethylbenzene purities of 99 % or higher. At this level, p-xylene may not be detected. 1.3 The following applies to all specified limits in this standard: for purposes of determining conformance with this standard, an observed value or a calculated value shall be rounded off "to the nearest unit" in the last right-hand digit used in expressing the specification limit, in accordance with the rounding-off method of Practice E 29. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For a specific hazard statement, see Section 7.

3. Summary of Test Method 3.1 A known amount of internal standard is added to the sample. A gas chromatograph equipped with a flame ionization detector and a polar fused silica capillary column is used for the analysis. The impurities are measured relative to the internal standard. Ethylbenzene purity is calculated by subtracting the impurities found from I00.00 %. 4. Significance and Use 4.1 The test is suitable for setting specifications on ethylbenzene and for use as an internal quality control tool where ethylbenzene is used in manufacturing processes. It may be used in development or research work involving ethylbenzene. 4.2 Purity is commonly reported by subtracting the determined expected impurities from 100 %. Absolute purity cannot be determined if unknown impurities are present.

2.1 A S T M Standards: D 3437 Practice for Sampling and Handling Liquid Cyclic Products 2 D 4307 Practice for Preparation of Liquid Blends for Use as Analytical Standards 3 E 29 Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications4 E 355 Practice for Gas Chromatography Terms and Relationships 4 E 1510 Practice for Installing Fused Silica Open Tubular Capillary Columns in Gas Chromatographs 4 2.2 Other Documents: OSHA Regulations, 29 CFR, paragraphs 1910.1000 and 1910.12005

5. Apparatus 5.1 Gas Chromatograph--Any gas chromatograph having a flame ionization detector and a splitter injector suitable for use with a fused-silica capillary column may be used, provided the system has sufficient sensitivity to obtain a minimum peak height response of 0.1 mV for 0.010 % internal standard when operated at the stated conditions. Background noise at these conditions is not to exceed 3 IxV. 5.2 Chromatographic Column, fused silica capillary, 60 m long, 0.32-mm inside diameter, internally coated to a 0.5-p-m thickness with a bonded (crosslinked) polyethylene glycol. Other columns may be used after it has been established that such column is capable of separating all major impurities and the internal standard from the ethylbenzene under operating conditions appropriate for the column. 5.3 Recorder, 1-mV, 1 s or less full scale response or electronic integration with tangent capabilities (recommended). 5.4 Microsyringe, 10-i.tL. 5.5 Microsyringe, 50-1xL. 5.6 Volumetric Flask, 50-mL.

1 This test method is under the jurisdiction of ASTM Committee D-16 on Aromatic Hydrocarbons and Related Chemicals and is the direct responsibility of Subcommittee DI6.OH on Styrene, Ethylbenzene, and C9 and Cto Aromatic Hydrocarbons. Current edition approved May 15, 1995. Published July 1995. Originally published as D 5090 - 90. Last previous edition D 5090 - 90. 2 Annual Book of ASTM Standards, Vol 06.04. 3 Annual Book of ASTM Standards, Vol 05.02. 4 Annual Book of ASTM Standards, Vol 14.02. s Avadable from Superintendent of Documents, U.S. Government Printing Office, Washington, DC 20402.

6. Reagents and Materials 6.1 Carrier Gas, hydrogen or helium, chromatographic grade. 6.2 Compressed Air, oil-free. 6.3 Hydrogen, chromatographic grade. 6.4 Nitrogen, chromatographic grade. 6.5 Pure Compounds for Calibration--n-Nonane, benzene, toluene, ethylbenzene, and o-xylene. The purity of the ethylbenzene should be 99.8 % or better. The ethylbenzene

2. Referenced Documents

783

(~ D 5060 TABLE 1

must be analyzed and corrections made in the composition of the calibration blend as required. The purity of all other compounds should be 99 % or greater. If the purity is less than 99 %, the concentration and identification of the impurities must be known so that the composition of the calibration standard can be adjusted for the presence of the impurities. 6.6 n-Undecane, for use as internal standard, 99 % or greater purity.

Typical Instrument Parameters

Carrier gas Carrier gas flow rate at 1100C, mL/m=n Detector Detector temperature, *C Injection port temperature, *C Hydrogen flow rate, mL/min Airflow rate, mL/min Make-up gas Make-up gas flow rate, mL/min Split flow, mL/min Column temperature, *C Chart speed, cm/min Sample size, pL

7. Hazards 7.1 Consult current OSHA regulations, supplier's Material Safety Data Sheets, and local regulations for all materials used in this test method.

helium 1.2 flame )onizat=on

240 230 30 275 nitrogen 23 150 110 1 0.6

and obtain the chromatogram. A typical chromatogram is shown in Fig. 1. 11. Calculation 11.1 Measure the areas of all peaks, including the internal standard, except for the ethylbenzene peak. 11.2 Sum all the peaks eluting before ethylbenzene except for benzene, toluene, and the internal standard. Identify this sum as nonaromatic hydrocarbons. 11.3 Calculate the weight percent of the individual impurities, Ci, to the nearest 0.001%, as follows:

8. Sampling 8.1 Guidelines for taking samples from bulk are given in Practice D 3437. 9. Calibration 9. I Prepare a calibration blend of each compound listed in 6.5 and n-undecane at the 0.2 weight % level in ethylbenzene as described in Practice D 4307. n-Nonane represents the nonaromatic hydrocarbons. A series of calibration blends that span the concentration range should be prepared, one at the expected level of impurities, another at one half the expected level, and a third series at twice the expected level. 9.2 Analyze the ethylbenzene used in preparing the calibration blend as described in 10.3. 9.3 Analyze the calibration blend as described in 10.3. 9.4 Calculate response factors as follows:

c,=

0.0512

A,R,

As where: Ai = area of impurity, R~ = response factor for impurity, and As = area of internal standard. 11.4 Use the response factor determined for o-xylene for all the peaks eluting after ethylbenzene, and the response factor determined for n-nonane for all the nonaromatic hydrocarbon peaks. 11.5 Calculate the purity of the ethylbenzene by subtracting the sum of the impurities from 100.00.

c, )

12. Report 12.1 Report the following information: 12.1.1 The concentration of each impurity to the nearest 0.001 weight %, and 12.1.2 The purity of ethylbenzene to the nearest 0.01 weight %.

where: R~ = response factor for impurity relative to internal standard, A~ = area of impurity peak in calibration blend, Ab --- area of impurity in ethylbenzene in calibration blend, Cs = concentration of internal standard, weight %, As,, -- area of internal standard peak in calibration blend, As, b = area of internal standard peak in stock ethylbenzene, and Ci = concentration of impurity, weight %. 9.5 Calculate response factor to the nearest 0.001.

13. Precision and Bias 13.1 The following criteria should be used to judge the acceptability of the 95 % probability level of the results obtained by this test method. The criteria were derived from a round robin between seven laboratories. The data were obtained over two days using different operators. 13.1.1 Intermediate PrecisioJt--Results in the same laboratory should not be considered suspect unless they differ by more than the amount shown in Table 2. 13.1.2 ReproducibilitymThe results submitted by two laboratories should not be considered suspect unless they differ by more than the amount shown in Table 2. 13.2 Bias--No statement is made about bias since no acceptable reference material and value are available.

10. Procedure 10.1 Install the chromatographic column and establish stable instrument operation at the operating conditions shown in Table 1. Refer to instructions provided by the manufacturer of the gas chromatograph and Practices E 355 and E 1510. 10.2 Fill a 50-mL volumetric flask to the mark with test specimen. With a microsyringe, add 30 IxL of the standard. Mix well. Using a density of 0.740 for n-undecane and 0.867 for ethylbenzene, this solution will contain 0.0512 weight % internal standard. 10.3 Inject 0.6 ~tL of solution into the gas chromatograph

14. Keywords 14.1 ethylbenzene; ethylbenzene purity; impurities in ethylbenzene 784

i{~'~ D 5 0 6 0 START

h.22

{-

~.s7

Non-aromatic Benzene

hydrocarbons .

.

.

.

.

S.12

.

Toluene

s.78

thyZbenzene

f

p-Xylene

.

.

.

.

,£

~ .7~ II :|~m_~y~ene 7.33

Cumene

9 -Xv~ene

E_

7.6z

7.ss

n-Propylbenzene Rrhv]to]uenes

ee30

sec-Butylbenzene 9.20

10.21 10.5~

Diethylbenzenes

P 11 .28

FIG. 1

TABLE 2 Component sec-Butylbenzene n-Propylbenzene m~o-Ethyltoluenes o-Xylene Cumene Benzene Toluene m,p-Xylene Diethylbenzenes Ethylbenzene

Typical Chromatogram (see Table 1) Intermediate Precision and Reproducibility Concentration, Intermediate Weight % Precision 0.002 0.010 0.014 0.013 0.012 0.024 0.592 0.090 0.008 99.05

0.001 0.002 0.003 0.004 0.003 0.004 0.083 0.024 0.001 0.200

Reproducibility 0.003 0.003 0.002 0.007 0.002 0.005 0.100 0.019 0.003 0.186

The American Society for Testing and Materials takes no position respecting the vafidity of any patent rights asserted m connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103.

785

(~l~

Designation: D 5134 - 92

Standard Test Method for Detailed Analysis of Petroleum Naphthas through n-Nonane by Capillary Gas Chromatography 1 This standard is issued under the fixed designation D 5134; the number immediately following the designation indicates the year of original adoption or, in the ease of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (¢) indicates an editorial change since the last revision or reapproval.

INTRODUCTION Despite the many advances in capillary gas chromatography instrumentation and the remarkable resolution achievable, it has proven difficult to standardize a test method for the analysis of a mixture as complex as petroleum naphtha. Because of the proliferation of numerous, similar columns and the endless choices of phase thickness, column internal diameter, length, etc., as well as instrument operating parameters, many laboratories use similar but nol identical methods for the capillary GC analysis of petroleum naphthas. Even minute differences in column polarity or column oven temperature, for example, can change resolution or elution order of components and make their identification an individual interpretive process rather than the desirable, objective application of standard retention data. To avoid this, stringent column specifications and temperature and flow conditions have been adopted in this test method to ensure consistent elution order and resolution and reproducible retention times. Strict adherence to the specified conditions is essential to the successful application of this test method. I. Scope I. 1 This test method covers the determination of hydrocarbon components of petroleum naphthas as enumerated in Table 1. Components eluting after n-nonane (bp 150.8"C) are determined as a single group. 1.2 This test method is applicable to olefin-free (<2 % olefins by liquid volume) liquid hydrocarbon mixtures including virgin naphthas, reformates, and alkylates. Olefin content can be determined by Test Method D 1319. The hydrocarbon mixture must have a 98 % point of 250"C or less as determined by Test Method D 3710. 1.3 Components that are present at the 0.05 mass percent level or greater can be determined. 1.4 The values stated in SI units are to be regarded as the standard. 1.5 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Specific warning statements are given in Section 7.

2. Referenced Documents

2.1 ASTM Standards: D 1319 Test Method for Hydrocarbon Types in Liquid Petroleum Products by Fluorescent Indicator Adsorption 2

D 3700 Practice for Containing Hydrocarbon Fluid Samples Using a Floating Piston Cylinder3 D3710 Test Method for Boiling Range Distribution of Gasoline and Gasoline Fractions by Gas Chromatography3 D4057 Practice for Manual Sampling of Petroleum and Petroleum Products3

3. Summary of Test Method 3.1 A representative sample of the naphtha is introduced into a gas chromatograph equipped with a methyl silicone bonded phase fused silica capillary column. Helium carrier gas transports the vaporized sample through the column in which the components are separated. Components are sensed by a flame ionization detector as they elute from the column. The detector signal is processed by an electronic data acquisition system or integrating computer. Each eluting peak is identified by comparing its retention index to a table of retention indices and by visual matching with a standard chromatogram. The tab!e of retention indices has been established by running reference compounds under identical conditions or by gas chromatographic--mass spectrometric (GC/MS) analysis of reference samples under the same conditions, or both. 3.2 The mass concentration of each component is determined by area normalization with response factors. Peaks eluting after n-nonane are summed and reported as C~o+. 4. Significance and Use 4.1 A knowledge of the hydrocarbon components comprising a petroleum naphtha, reformate, or alkylate is useful

J This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee I:)02.04 on Hydrocarbon Analysis. Current edition approved Aug. 15, 1992. Published October 1992. Originally published as D 5134 - 90. Last previous edition D 5134 - 90 ~j. 2 Annual Book of ASTM Standards, Vol 05.01.

3 Annual Book of ASTM Standards, Vol 05.03.

786

~1~ D 5134 TABLE

1

Typical Retention Characteristics of Naphtha Components

Compound Methane Ethane Propane Isobutane n-butane 2,2-Dimethylpropane Isopantane n-Pentane 2,Dimethylbutane Cyciopentane 2,3-Dimethylbutane 2-Methylpantane 3-Methylpantane n-Hexane 2,2-Dimethylpantane Methylcyclopantane 2,4-Dimethylpantane

2,2,3-TrimethyJbutane Benzene 3,3-dimethylpantane Cyclohexane 2-Methylhexane 2,3-Dimethylpantane I, 1-Dimethylcyclopantane 3-Methylhexane cia- 1,3-Dimethylcyclopantane

trans-l,3-Dimethylcyclopantane 3-Ethylpentane

trans- 1,2-DimethylcycJopentane 2, 2, 4oTrimethylpantane n-Heptane Methylcyciohexane + c/s- 1,2-Dimethylcyclopentane 1,1,3-Tdmethylcyciopantane + 2,2-Dirnethylhexane Ethylcyclopantane 2,5-Dimethylhexane + 2,2,3-Tdmethylpantane 2,4-Dimethylhexane

1,trans-2,cla-4-Trimethylcydopantane 3.3-Dimethylhexane

1,trana.2,cia-3-Tdmethylcyclopantane 2,3,4,Trimethylpantane Toluene + 2,3,3-Tdmethylpantane I, 1,2-Tdmethylcyclopantane 2,3-DimethyU'mxane

2-Methyl-3-ethylpentane 2-Methylheptane 4-Methylheptane + 3oMethyl-3-ethylpantane 3,4-Dimethylhexane

1,cia-2,trana-4.Tdrnethylcyclopentane + 1,ci$-2,cis-4.Tdmathylcyclopantane cis-l,3.Dimethylcyclohexane 3-Methylheptane + 1,cis.2,trans-3-Tdrnethylcyclopentane 3-Ethylhexane + trans-l,4.Dimethylcyclohexane 1, l-Dimethyioyciohexane 2,2,5-Tdrnethylhexane + trana-1,3-Ethylmethylcyctopentane cis-l,3-Ethylmethylcyclopantane trans- 1,2.Ethylmethylcyclopantane 2,2,4-Trimethylhexane + I, l.Ethylmethylcyclopantane

trans, 1,2-Dimethylcyciohexane 1,cia.2,cis-3-Tdmethylcyclopantane trana-l,3-Dimethylcyciohexane + cia-l,4-Dimethylcydohexane n-Octane Isopropylcyclopentane + 2,4,4-Tdmethylhexane Unidentified Cg-Naphthene Unidentified CS-Naphthane Unidentified C9.Naphthene cis-l,2-Ethylmethylcyciopantane + 2,3,5-Trimethylhexane 2,2-Dimethylheptane

cia- 1,2-Dirnethylcyclohexane 2,2,3-Tdmethylhexane + 9N 2,4-Dimethylheptane 4.4-Dimethylheptane + 9N

787

Retention Time. min

Adjusted Retention Time. min

3.57 3.65 3.84 4.14 4.39 4.53 5.33 5.84 6.81 7.83 7.89 8.06 8,72 9.63 11.22 11,39 11.68 12.09 13.29 13.84 14.19 15.20 15.35 15.61 16.18 16.88 17.22 17.44 17.57 17.80 19.43 22.53 23.05 24.59 25.12 25.47 26.43 26.79 28.01 28.70 29.49 31.21 31.49 31.69 33.06 33.34 33.49 33.73 34.45 34.64 34.83 35.81 36.75 37.14 37.39 37.68 38.14 39.21 39.54 39.91 40.76 40.88 41.52 41.88 42.55 43.20 43.43 43.76 43.88 44.09

0.00 0.08 0.27 0.57 0.82 0.96 1.76 2.27 3.24 4.26 4.32 4.49 5.15 6.06 7.65 7.82 8.11 8.52 9.72 10,27 10.62 11.63 11.78 12.04 12.61 13.31 13,65 13.87 14.00 14,23 15.86 18.96 19.48 21.02 21.55 21.90 22.86 23.22 24.44 25.13 25.92 27.64 27.92 28.12 29.49 29.77 29.92 30.16 30.88 31.07 31.26 32,24 33,18 33.57 33.82 34.11 34.57 35.64 35.97 36.34 37.19 37.31 37.95 38.31 38.96 39.63 39.86 40.19 40.31 40.52

Kovats Retention IndexC @35o 100,0 200.0 300.0 367.3 400.0 415.5 475.0 500.0 536.2 564.1 565.5 569.5 583.4 600.0 624.2 626.5 630.3 635.4 649.1 654.8 658.3 667.8 669.1 671.4 676.2 681,8 664.4 686.1 687.0 688.7 700.0 718.6A 721.4* 729.3 A 731.9 A 733.5 A 738.0 A 739.6 A 744.9 A 747.8 A 751.1 A ... ... ... . .. ... ... ... ... ... ... ... ... ... ... ... ... ... ,.. ... ... ... .,. .

.

.

... ... ,.. ,,, ... ...

Linear Retention Index ... ... ... ... ... ... ... ... ... ,.. ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... .,. ... ... ... ... ... 7:3().2m 741.7 e 743.6 e

744.9 s 754.1 e 756.0 e 757.0 e 758.6 e 763.4 e 764.7 e 766.0 a 772.5 e 778.8 e 781.4 e 783.1 a 785.1 • 788.1 a 795.3 s 797.5 e 800.0 805.7 806.5 810.8 813.2 817.7 822.0 823.6 825.8 826.6 828.0

~ D 5134 TABLE 1

Continued

Compound Ethylcyclohexene+ n-Propylcyclopentene 2-Methyt-4-Ethylhexene 2,6-Oimethylheptene + 9N 1,1,3-Trimethylcyclohexene Unidentified Cg-Naphthene 2,5-Dimethylheptene + 9P 3,5-Dimethylheptene + 3,3-Dimethylheptane+ N Unidentified C9-Naphthene Unidentified C9-Naphthene Ethyl Benzene Unidentified C9-Naphthene Unidentified Naphthene + 2,3,4-Tdmethylhexane Unidentified Naphthenes Unidentified Naphthene + Paraffin m-Xylene p-Xylene 2,3-Dimethylheptene 3,4-Dimethylheptene c + N 3, 4-Dimethylheptane c Unidentified Naphthene 4-Ethylheptene + N 4-Methyloctene 2-Methyloctane Unidentified Naphthene Unidentified Naphthene 3-Ethylheptane + N 3-Methyloctene Unidentified Naphthene o-Xylene + I, 1,2-Trimethylcyclohexene Unident=fied Naphthene + 2,4,6-Trirnethylheptene Unidentified Naphthene Unidentified Paraffin Unidentified Naphthenes Unidentified Naphthene Unidentified Naphthene + Paraffin Unidentified Naphthene Unidentified Naphthene Unidentified Naphthene Unidentified Naphthene n-Nonane Unidentified Naphthene

Retention Time, mln

Adjusted Retention T=me, rain

44.36 44.74 44.95 45.21 45.56 45.92 46.09 46.31 46.55 47.15 47.37 47.53 47.78 48.13 48.49 48.63 48.93 49.10 49.29 49.41 49.65 50.10 50.26 50.41 50.73 50.96 51.15 51.35 51.54 51.74 52.12 52.24 52.56 52.85 53.06 53.26 53.46 54.02 54.40 54.84 54.98

40.79 41.17 41.38 41.64 41.99 42.35 42.52 42.74 42.98 43.58 43.80 43.96 44.21 44.56 44.92 45.06 45.36 45.53 45.72 45.84 46.08 46.53 46.69 46.84 47.16 47.39 47.58 47.78 47.97 48.17 48.55 48.67 48.99 49.28 49.49 49.69 49.89 50.45 50.83 51.27 51.41

Kovats Retention Index @35"C

Linear Retention Index 829.8 832.4 833.8 835.5 837.8 840.3 841.4 842.9 844.5 848.5 850.0 851.0 852.7 855.1 857.5 858.4 880.4 861.6 862.8 863.6 865.2 868.3 869.3 870.3 872,5 874,0 875.3 876.6 877.9 879.2 881.8 882.6 884.7 886.7 888.1 889.4 890.8 894.5 897.1 900.0 900.9

A Extrapolated from n-Ce and n-C7. See Annex (A1.1.3). B Extrapolated from n-Ca and n-Cg. See Annex (A1.2.3). c Stereoisomers. NOTE~The abbreviations N end P refer to unidentified naphthenes and paraffins respectively.

in valuation of crude oils, in alkylation and reforming process control, in product quality assessment, and for regulatory purposes. Detailed hydrocarbon composition is also used as input in the mathematical modeling of refinery processes. 4.2 Separation of naphtha components by the procedure described in this test method can result in some peaks that represent coeluting compounds. This test method cannot attribute relative concentrations to the coelutants. In the absence of supporting information, use of the results of this test method for purposes which require such attribution is not recommended.

saturates or aromatics and give erroneously high concentrations for those components. 5.2 Alcohols, ethers, and other organic compounds of similar volatility can also interfere by coeluting with saturate or aromatic hydrocarbons thereby causing erroneously high values to be determined. 6. Apparatus 6.1 Instrumentation--A gas chromatograph capable of column oven temperature programming from 35"C to 200"C in l*C/min increments is required. A heated flash vaporizing injector designed to provide a linear sample split injection (for example, 200:1) is also required for proper sample introduction. The associated carrier gas controls must be of adequate precision to provide reproducible column flows and split ratios in order to maintain analytical integrity. A hydrogen flame ionization detector designed for optimum response with capillary columns (with the required gas controls and electronics) must meet or exceed the following

5. Interferences 5.1 If present, olefinic hydrocarbons with boiling points less than 150°C will be separated and detected along with the saturates and aromatics. Some of the olefins will coelute with

788

~) D 5134 specifications:

tremely flammable. Harmful if inhaled.) 7.12 Column Evaluation Mixture, a qualitative synthetic mixture of pure liquid hydrocarbons with the following approximate composition-0.5 % toluene, 1% n-heptane, 1% 2,3,3-trimethylpentane, 1% 2-methylheptane, 1% 4methylheptane, 1% n-octane in 2-methylpentane solvent. 7.13 Reference Alkylate, 5 actual refinery alkylation product used to prepare Fig. 1. (Warning--Extremely flammable. Harmful if inhaled.) 7.14 Reference Naphtha, 5 actual refinery stream used to prepare Fig. 2. (Warning--Extremely flammable. Harmful if inhaled.) 7.15 Reference Reformate, 5 actual refinery reformer product used to prepare Fig. 3. (Warning--Extremely flammable. Harmful if inhaled.)

Operating temperature ................. 100°C to 300°C Sensitivity ..................................... >0.015 C/g Minimum detectability ................ 5 × 10 - t 2 g carbon/second Linearity ....................................... >i07 6.2 Sample Introduction System--Manual or automatic liquid syringe sample injection to the splitting injector may be employed. Devices capable of 0.2 p.L to 1.0 ~tL injections are suitable. It should be noted that inadequate splitter design or poor injection technique, or both, can result in sample fractionation. Operating conditions which preclude fractionation should be determined in accordance with Section 11. 6.3 Electronic Data Acquisition System--Any data acquisition and integration device used for quantitation of these analyses must meet or exceed these minimum requirements: 6.3.1 Capacity for at least 250 peaks/analysis. 6.3.2 Normalized area percent calculation with response factors. 6.3.3 Identification of individual components by retention time. 6.3.4 Noise and spike rejection capability. 6.3.5 Sampling rates for fast (<1 s) peaks. 6.3.6 Positive and negative sloping baseline correction. 6.3.7 Peak detection sensitivity for narrow and broad peaks. 6.3.8 Perpendicular drop and tangent skimming as needed. 6.4 Capillary Column--This test method utilizes a 50-m (0.21-mm inside diameter) fused silica capillary column 4 with bonded (cross-linked) methyl silicone phase and a film thickness (df) of 0.5 ~tm. Other columns with these nominal dimensions may be suitable. However, all columns must meet the criteria set out in Section 10 for efficiency, resolution, and polarity.

8. Sampling 8.1 Hydrocarbon liquids (including naphthas) with Reid vapor pressures of 110 kPa (16 psi) or less may be sampled either into a floating piston cylinder or into an open container. 8.1.1 Cylinder Sampling--Refer to Test Method D 3700 for instructions on transferring a representative s,3.mple of a hydrocarbon fluid from a source into a floating piston cylinder. Add inert gas to the ballast side of the floating piston cylinder to achieve a pressure of 350 kPa (45 psi) above the vapor pressure of the sample. 8.1.2 Open Container Sampling--Refer to Practice D4057 for instructions on manual sampling from bulk storage into open containers. Stopper container immediately after drawing sample. 8.2 Preserve the sample by cooling to approximately 4"C and by maintaining that temperature until immediately prior to analysis. 8.3 Transfer an aliquot of the cooled sample into a precooled septum vial, then seal appropriately. Obtain the test specimen for analysis directly from the sealed septum vial, for either manual or automatic syringe injection.

7. Reagents and Materials 7.1 Carrier Gas, helium, 99.99 % pure. (Warning--Com-

9. Preparation of Apparatus

pressed gas under high pressure.) 7.2 Fuel Gas, hydrogen, 99.99 % pure. (Warning--Extremely flammable gas under pressure.) 7.3 Make-up Gas, helium or nitrogen, 99.99 % pure. (Warning--Compressed gases under higher pressure.) 7.4 n-Heptane, 99+ tool %. (Warning--Flammable. Harmful if inhaled.) 7.5 Methane--(Warning--Extremely flammable gas.) 7.6 2-Methylheptane, 99+ rnol %. (Warning--Flamma. ble. Harmful if inhaled.) 7.7 4-Methylheptane, 99+ tool %. (Warning--Flammable. Harmful if inhaled.) 7.8 2-Methylpentane, 99+ tool %. (Warning--Extremely flammable. Harmful if inhaled.) 7.9 n-Octane, 99+ mol %. (Warning--Flammable. Harmful if inhaled.) 7.10 Toluene, 99+ tool %. (Warning--Flammable. Vapor harmful.) 7.11 2,3,3-Trimethylpentane, 99+ tool %. (Warning--Ex-

9.1 Install and condition column as per manufacturer's or supplier's instructions. After conditioning, attach column outlet to flame ionization detector inlet and check for leaks throughout the system. If leaks are found, tighten or replace fittings before proceeding. 9.2 Calibrate the gas chromatograph column oven temperature sensors using an independent, electronic temperature measuring device such as a thermocouple or platinum resistance temperature detector. 9.2.1 Place the independent temperature measuring probe in the oven in the region occupied by the column. Do not allow sensor to touch the walls of the oven. 9.2.2 Set the oven temperature to 35"C and allow oven to equilibrate for at least 15 rain, then observe the temperature reading. 9.2.3 If the reading of the independent temperature sensor is more than 0.5"C different from 35"C, follow manufacturer's instructions to adjust calibration of GC oven temperature.

(Columns (designated HP-PONA) obtainable from Hewlett-Packard Com-

5These qualitative reference samples are available from Supelco, Inc.. lkllefonte, PA.

pany, Avondale, PA, have been found satisfactory.

789

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I 23.00

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(b) 15-31 min retention times

(a) 0-15 min retention times t2.0~

6.0q

9.~

4.1(

7.21

j ]

,i j

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2.4q

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(c) 31-43 mln retention times i.¢(

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oo

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FIG. 1

Reference Nkylate Ch~matogram

head pressure) until the retention time of methane on the 50-m column is 3.6 rain. 9.4.2 Make final adjustments to flow rate so that toluene is retained for the specified 29.6 _+ 0.2 min. As this specification is critical to achieving reproducibility of retention times among different laboratories, care must be taken that the toluene does not overload the column and cause skewed peaks with resultant shifts in peak apex position. Injection of a 1% toluene solution should preclude this possibility.

NOTE 1: Caution--Differences of as little as I°C can change the resolution of two closely eluting peaks (of dissimilar hydrocarbon types) enough to affect integration and quantitation while 2 to 3°C may cause those same peaks to be unresolved or even reverse their elution order.

9.3 Adjust the operating conditions of the gas chromatograph to conform to the list in Table 2. Turn on the detector, ignite flame, and allow the system to equilibrate. 9.4 Set carrier gas flow rate such that the retention time of toluene at 35°C is 29.6 _+ 0.2 min. 9.4. l As a matter of practicality, it may be easier to first set an approximately correct flow rate, using methane gas injections. To do this, adjust the carrier gas flow (or column

10. Column Evaluation 10.1 In order to establish that a column will perform the 790

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2

R e f e r e n c e Naphtha C h r o m a t o g r a m

required separation, certain specifications must be met with respect to efficiency, resolution, and polarity. Determine the following data for new columns. Check older columns on a periodic basis to ensure that column deterioration has not occurred. A column which does not meet these specifications is unsuitable for use. 10.2 Set oven temperature parameters for isothermal operation. Under isothermal conditions at 35"C, inject ~25 ~tL of methane and record the retention time. Also at 35"C, analyze the column evaluation mixture described in 7.12. Record the retention times and the peak widths at half height of each of the components.

10.2.1 Calculate efficiency of the column using Eq 1. The number of theoretical plates (n) must be greater than 225 000. n = 5.545

(tR/Wh)2

(1)

where: n - number of theoretical plates, tR = retention time of n-octane, and Wh = peak width of n-octane at half height (in same unit as retention time). 10.2.2 Calculate resolution (R) between 2-methylheptane and 4-methylheptane using Eq 2. R must be at least 1.35.

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where: R -IR(A) = lR(;J) = Wh(tt ) = Whim =

2(tnta) - trim) i.699 (WhtA~ + Whim)

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(e) 55-95 min retention times Reference Reformnte Chromatogrnm

of the column /(2.3,3.TMP)-/(Toluene) must be 0.4 + 0.4 at 350C.

(2)

NOTE 2: Caution--This specification is critical. Seemingly slight differences in the polarity have a significant effect on the relative order of elution of components, thus making peak identifications difficult.

resolution, retention time of 4-methylheptane, retention time of 2-methylheptane, peak width at half-height of 4-methylheptane, and peak width at half-height of 2-methylheptane.

10.2.3.1 Kovats Retention Index is given by: IA

10.2.3 Determine relative polarity o f t h e column using the difference in Kovats Retention Indices (Annex A l) of toluene and 2 , 3 , 3 - t r i m e t h y l p e n t a n e . The relative polarity

700 +

Iogt'RtA)-- log t'RtC7 ) log t'RtCa) -- log t'RtC7)

where: IA -- retention index o f component eluting between n C7 and n - Ca, 792

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D 5134

mixture by area normalization with response factors. Use a response factor of 1.00 for all compounds except benzene (0.90) and toluene (0.95), Determine the relative error of the calculated concentrations from the known concentrations.

= adjusted retention time o1 component,

l',,¢(C,7) -~ adjusted retention time of n-heptane, and

t'n(c~)

= adjusted retention time of n-octane. 10.2.3.2 Adjusted retention time of a peak is determined by subtracting the retention time of an unretained substance (methane) from the retention time of the peak. 10.2.3.3 If 2,3,3-trimethylpentane and toluene are not resolved, run separate mixtures, each containing only one of these compounds along with n-C7 and n-Ca in n-hexane solvent.

% relative error 100 x (calculated concentration - known concentration) =

(4)

NOTE 3--Petroleum naphtha samples may contain appreciable quantities of highly volatile components. Samples should be chilled in their original container to 4"C (39°F) before opening for subsampling or

transfer (see Section 8). 13. Calculation 13.1 Identify each peak by visually matching it with its counterpart in the appropriate standard chromatogram, Fig. 1, 2, or 3. Make allowances for differences in relative peak sizes with different samples. Peaks eluting after n-nonane are not identified individually.

Injection Temperature: 200"(2. Split: 100:1 Sample: .2, .5, 1.0 p.L Split: 200:1 Sample: .2, .5, 1.0 pL Injection Temperature: 250°C. Split: 100:1 Sample: .2, .5, 1.0 I~L Split: 200:1 Sample: .2, .5, 1.0 gL I !.4 Calculate the concentration of each compound in the

Temperature: Split ratio: Sample size: Deteotor Type: Temperature: Fuel gas: Oxidizing gas: Make-up gas: Carrier Gas Type: Average linear velocity:

= ~. . . . .

12. Procedure for Gas Chromatographic Analysis of Sample 12.1 Set the instrument operating variables to within the limits specified in Table 2. If necessary, change split ratio, sample size, or injection port temperature, or combination thereof, to ensure splitter linearity as determined in Section II. 12.2 Verify that the isothermal retention time of toluene (at 35"C) is 29.6 _+ 0.2 min as discussed in 9.4. 12.3 Set the recorder or integration device, or both, for accurate presentation of the data. Set up instrument sensitivity such that any component of at least 0.05 % mass will be detected, integrated, and reported. 12.4 Inject 0.2 to 1.0 I~L of sample into the injection port and start the analysis. Sample size must be consistent with the splitter linearity range as determined in Section I I. Obtain a chromatogram and peak integration report.

11.1 The choice of split ratio used is dependent upon the split linearity characteristics of the particular injector and the sample capacity of the column. Overloading of the column may cause loss of resolution for some components and, since overloaded peaks are skewed, variance in retention times. This can lead to erroneous component identification. During column evaluations and split linearity studies, watch for any skewed peaks that may indicate overload. Note the component size and where possible, avoid conditions leading to this problem during actual analyses. 11.2 Splitting injector linearity should be established to determine proper quantitative parameters and limits. Use a standard mixture of known weight percentages of 10 to 20 pure (99+ %) hydrocarbons, covering the boiling range of this test method. To prevent losses due to volatility, do not use any compounds lighter than n-hexane. 1 !.3 Inject and integrate this standard under the following conditions, using the operating conditions listed in Table 2. Split ratio may be determined by direct flow measurements or by calculation as shown in Annex A2. Faster temperature programming may be used as long as the components are eluted as discrete peaks.

Column Temperature Program Initial temperature: Pre-injectionequilibration time: Initial hold time: Program rate: Final temperature: Final hold time: Injector

..........

11.5 Use only those combinations of conditions from 11.3 which result in 3 % or less relative error. This is the splitter linearity range.

11. Split Injection Linearity

TABLE 2

,

known concelltratlon

NOTE 4--To aid the analyst in setting up this test method and identifying peaks in the chromatograms, qualitative reference samples of the

Operating Conditions

alkylate, naphtha, and reformate actually used to generate Figs. I, 2, and 3 are available. Each can be analyzed and its chromatogram compared directly with the corresponding figure to assist in peak assignments.

35°C ± 0.5°C 5 min 30 rain 2°C/rain 200°C 10 min

13.2 Each peak can also be identified by matching its retention index with that of the compounds listed in Table 1. Equations for calculating retention indices are given in Annex A I. Retention indices of compounds eluted during the initial isothermal portion of the analysis must be calculated using the Kovats equation. Retention indices of all other components must be calculated using the equation for linear indices. Differences from the values in the table must be allowed for due to slight differences in columns, temperature, and flow. As noted in I I. l, retention times and therefore retention indices also vary as a result of column overload. 13.3 If a computing integrator is used for automatic identification, examine the report to ensure peaks are properly identified.

200°C 200:1 0.2 to 1.0 pL flame ionization 250°C hydrogen (-30 mL/min) air (-250 mL/min) nitrogen (-30 mL/min) helium -23 cm/s @ 35°C (see 9.4)

NOTE 5--Caution--Careful review of peak identifications is extremely important. Failure to do so may result in serious errors. 793

~

O 5134 TABLE 3

Repeatability and Reproducibility for Selected Naphtha Components Component Name Repeatability Reproducibility Isobutane 0.071 (x)o.es 0.13(x )o es n-Butane 0.091(x) °.en 0.17(x)°.as Isopentane 0.072(x )o.e7 0.17(x )o.e7 n-Pentene 0.051(x )o.e7 0.14(x )o.e7 Cyciopentene A 0.026(x )o.so 0.087(x )o so 2,3-Oimethylbutene A 0.027(x )o.e7 0.12(X)° e7 3.Methylpentane 0.015(x) 1'0.034(x) Methylcyclopentane 0.016(x) t0.038(x) Benzene 0.037(x)o.e7 0.092(x)O e~, 2,3-Dimethylpentane A 0.014(x) 0.051 (x) 3-Ethylpentane A 0.019(x) 0.094(x) n-Heptene 0.012(x)O so 0.030(x)O.SO trans- l ,2.Dimethylcyciopentene A 0.016(x) 0.053(x) MethylcycJohexane 0.065(x)°'s° 0.16(x)°'s° Toluene 0.015(x) 0.031(x) 2,5-Dimethylhexane 0.012(x) 0.030(x) 2-Methylheptane 0.037(x)°-s° 0.094(x)°.s° n.Octane 0.010(x) 0.070(x) trans-l,2.Dlmethylcyclohexane 0.010(x) 0.024(x) I, 1-Dlmethylcyctohexene 0.0095 Yo 0.023 % j~'Xylene A 0.018(x ) 0.15(x ) 2,2-Dimethylheptane 0.0050 % 0.0099 % 4-Methyloctane~ 0.029(x) o,eo 0.073(x)o,so n-NoneneA 0.017(x) 0.050(x)

13.4 Sum the areas of all peaks eluting after n-nonane. This group will be treated as a single component, Cm*. 13.5 Calculate the mass percent of each component (including Cto-) according to the following equation: Mass % component i =

A i X Bi

z (A, x B,)

x 100

(5)

where: Ai = area of peak representing component i, and B; = relative mass response factor for component i. Use a response factor of 1.00 for all components except benzene (0.90) and toluene (0.95). 14. Report 14.1 Report the mass percent and identity of each component through n-nonane to the nearest 0.01%. 14.2 Report the mass percent of Cm- to the nearest 0.01%. 14.3 Report the total mass percent of all unidentified components through n-nonane.

15. Precision and Bias6 15.1 Precision--The precision of any individual measurement resulting from the application of this test method depends on several factors including the volatility of the component, its concentration, and the degree to which it is resolved from other closely eluting components. As it is not practical to determine the precision of measurement for every component (or group of components) separated by this test method, Table 3 presents the repeatability and reproducibility values for selected, representative components. 15. I. 1 Repeatabilitp---The difference between successive test results obtained by the same operator with the same apparatus under constant operating conditions on identical test materials would, in the long run, in the normal and correct operation of the test method, exceed the repeatability values shown in Table 3 only in one case in twenty.

A Component that is incompletely resolved. (x) refers to the mass percent component found. 1' Editorially oorr~ted.

15.1.2 Reproducibility--The difference between two single and independent test results obtained by different operators working in different laboratories on identical test materials would, in the long run, in the normal and correct operation of the test method, exceed the values shown in Table 3 only in one case in twenty. 15.2 Bias--Bias in the measurements resulting from the application of this test method cannot be determined since there is no accepted reference material suitable for determining bias. 16. Keywords alkylate; capillary gas chromatography; hydrocarbon composition; petroleum naphtha; reformate

6 Supporting data are available from ASTM Headquarters. Request RR:D021265.

ANNEX

(Mandatory Information) AI. KOVATS AND LINEAR RETENTION INDICES A1.1 The logarithmic Kovats Retention Index 7 is a gas chromatographic parameter characteristic of a solute's relative retention on a specified liquid phase at a specified (isothermal) temperature. It is a very useful tool in the qualitative identification of chromatographic peaks. A I. 1.1 Based on the observation that under isothermal conditions the adjusted retention times of members of a homologous series increase logarithmically with increasing carbon number, the Kovats Retention Index is a number indicating (on a logarithmic scale) the retention of a corn-

pound relative to the series of n-alkanes. (Adjusted retention time is the actual retention time minus the retention time of an unretained component such as methane.) A1.1.2 The equation used to calculate the Kovats Retention Index I~so of a compound A is given by Eq A 1.1:

llsoffi100x N + I00 x ( log I'R(~)- log t'R(N) ~ (AI.I) \log I'R(N+I) -- log I'R(N)] where t'm,v) and t'~(N+,)are the adjusted retention times of n-alkanes of carbon number N and N + l that are respectively smaller and larger than t'R(A),the adjusted retention time of a compound A. AI.I.3 Over a limited range and with some loss in

E. Kovats, Advances in Chromatography, Voi I, 1964.

794

~ accuracy, Kovats Retention Indices can be calculated by extrapolation rather than interpolation. In such case N and N + I would be defined as the carbon numbers of consecutive n-alkanes, both eluting immediately before (or after) compound A. The equation otherwise remains unchanged. A I.I.4 By definition the Kovats Retention Indices of n-alkanes are 100 x N (for example, for n-hexane, I = 600 and for n-heptane, I = 700). AI.I.5 Kovats Retention Indices are calculated from adjusted retention times obtained from a strictly isothermal analysis or from the initial isothermal temperature hold portion (if used) of a programmed temperature analysis. One may not utilize data from isothermal portions of an analysis which follow temperature changes incurred during a run. A1.1.6 These indices are independent of other operating parameters. Kovats Retention Indices calculated from retention times determined on any suitable chromatographic system can be compared directly with those from any other suitable system as long as the liquid phase and the temperature are the same. Published compilations are an excellent source of indices for identification purposes. A 1.2 The Linear Retention Index a is an extension of the Kovats concept to programmed temperature gas chromatography. The Linear Retention Index of a solute is dependent not only on the liquid phase but on other operating parameters as well. It is a useful indicator of relative retention of solutes on chromatographic systems operating under identical or nearly identical conditions. a Van den Dool and Dratz, Journalof Chromatography Vol I I, p. 463, 1963.

D 5134 AI.2.1 Based on the approximation that under programmed temperature conditions the actual retention times of members of a homologous series increase linearly with increasing carbon number, the Linear Retention Index is a number indicating (on a linear scale) the retention of a compound relative to the series of n-alkanes. AI.2.2 The equation used to calculate the Linear Retention Index (I~,,.,,~) of a compound A is given by Eq A I.2: /" tR("a'---~)--"tR('v---2-~

lp,,,g = 100 × N + 100 x ~tRt~+l) -- lR(lv)]

(AI.2)

where tR is the actual retention time and the subscripts, A, N, and N + 1 are defined as in Al.I.2 above. AI.2.3 Over a limited range and with some loss in accuracy, Linear Retention Indices can be calculated by extrapolation rather than interpolation. In such cases, N and N + 1 would be defined as the carbon numbers of consecutive n-alkanes, both eluting immediately after (or before) compound A. The equation otherwise remains unchanged. AI.2.4 By definition, the Linear Retention Indices of n-alkanes are 100 x N (for example, for n-octane, I = 800 and for n-nonane, I - 900). AI.2.5 The usual application of the Linear Retention Index system is to linear programmed temperature analyses without isothermal plateaus (even at the beginning of the run). However, since the indices are generally limited to analyses with essentially identical operating conditions anyway, some analysts have used the Linear Retention Index system to reduce data from procedures utilizing complex temperature profiles. Such indices are not theoretically defensible, but nevertheless are useful indicators of relative retention especially for standard test methods.

795

i~ D 5134 A2. M E A S U R E M E N T AND C A L C U L A T I O N OF F L O W P A R A M E T E R S where d, is the internal diameter of the column, cm. A2.2.6 Cohtmn Carrier Gas Flow Rate (cm3/inin): F,. = p,, x A,. x 60 (A2.6) A2.3 Injection Split Ratio:

A2.1 Column flow rate can be measured directly on some instruments at the flame ionization detector jet using a soap film flow-meter. This is the preferred way as long as all other gas flows can be turned off during the measurement, A2.2 Column flow rate can also be calculated from column dimensions and flow parameters using the following series of equations: A2.2. l Column Hold, up Time (s): i,. = retention t i m e of methane (A2.1)

,%.+F,. F,.

Split ratio =, ~

where F, is the directly measured flow rate through the

splitter vent. A2.4 Example--Given a 50-m column of 0.21-mm inside diameter, inlet pressure of 220 kPa (gage), outlet pressure of 101 kPa (absolute), retention time of methane of 3.62 min, and flow out the splitter vent of 200 crn3/min, calculate column flow rate and split ratio as follows: tm = 3.62 rain = 217 s

A.2.2.2 Average Linear Gas Velocity (cm/s):

"p = L/tm where L is the column length, cm. A2.2.3 Gas Compressibility Correction Factor: 3 x (p2 _ 1) J = 2 ~'~ I)

(A2.2)

= (5000)/(217) = 23.0 cm/s p= (220 kPa + 101 kPa) = 3.18 101 kPa j = 3 / 2 x [(3.182 - 1)/(3.!83 - I)] = 0.438 Po = 23.0/0.438 ,= 52.5 cm/s

(A2.3)

where p is the ratio of column inlet to column outlet absolute pressure. A2.2.4 Column Outlet Linear Velocity (cm/s): p.,, = "p/j (A2.4) A2.2.5 Column Cross.Sectional Area (cm~): Ac='

4

(A2.7)

• " X (0.021) 2 = 0.000346 cm 2

A,. = 4 F,. = 52,5 x 0.000346 x 60 = 1.09 cm3/min Split ratio = (200 + 1.09)/1.09 = 184:1

(A2.5)

The American Society for Teetlng and Materials takes no peeltlon respecting the validity of any patent rights asserted In connection with any item mentioned in this standard. Uaere of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of Infringement of such rights, ere entirely their own responsibility. This standard is subject to revision st any time by the responsible technical committee and muet be reviewed every five years and ff not revised, either reepproved or withdrawn. Your comments are Invited either for revision of this standard or for additional standards and should be addreesed to ASTM Headquarters. Your comments will receive careful consideration st a meeting of the responsible technical committee, which you may attend, ff you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103.

796

~l~

Designation:D 5135 - 95 Standard Test Method for Analysis of Styrene by Capillary Gas Chromatography 1 This standard is issued under the fixed designation D 5135; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript ¢psilon (~) indicates an editorial change since the last revision or reapproval.

1. Scope 1.1 This test method covers the determination, of the impurities in, and the purity of styrene by gas chromatography. It is applicable to styrene in the range from 99 to 100 % purity and to impurities at concentrations of 0.001 to 1.00 %. This test method may be used for lower purity but not all the impurities may be readily identified and the use of an internal standard becomes more difficult. 1.2 The following applies to all specified limits in this standard: for purposes of determining conformance with this standard, an observed value or a calculated value shall be rounded off "to the nearest unit" in the last right-hand digit used in expressing the specification limit, in accordance with the rounding-off method of Practice E 29. 1.3 This standard does not purport to address all the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For a specific hazard statement, see Section 6. 2. Referenced Documents 2. I A S T M Standards: D 3437 Practice for Sampling and Handling Liquid Cyclic Products2 E 29 Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications 3 E 1510 Practice for Installing Fused Silica Open Tubular Capillary Columns in Gas Chromatographs3 2.2 Other Document: OSHA Regulationsm29CFR paragraphs 1910.1000 and 1910.12004 3. Summary of Test Method 3.1 In this test method, the chromatogram peak area for each impurity is compared to the peak area of the internal standard (n-heptane or other suitable known) added to the sample. From the response factors of these impurities relative to that of the internal standard and the amount of internal standard added, the concentration of the impurities are calculated. The styrene content is obtained by subtracting

the total amount of all impurities from 100.00.

4. Significance and Use 4.1 This test method is designed to obtain styrene purity on the basis of impurities normally present in styrene and may be used for final product inspections and process control. 4.2 This test method will detect the following impurities: non-aromatic hydrocarbons containing ten carbons or less, ethylbenzene, p- and m-xylene, cumene, o-xylene, npropylbenzene, m- and p-ethyltoluene, alpha-methyl-styrene, m- and p-vinyltoluene and others where specific impurity standards are available. Absolute purity cannot be determined if unknown impurities are present. 5. Apparatus 5.1 Gas ChromatographmAny gas chromatograph having a flame ionization detector and a splitter injector suitable for use with a fused silica capillary column may be used, provided the system has sufficient sensitivity to obtain a minimum peak height response of 0.1 mV for 0.010 % internal standard when operated at the stated conditions. Background noise at these conditions is not to exceed 3 IxV. 5.2 Column--Capillary columns have been found to be satisfactory. For example, 60 m of 0.32-mm inside diameter polar-fused silica capillary internally coated to a 0.5-~tm thickness with a bonded (cross-linked) polyethylene glycol can be used (see Table 1 for parameters). Other columns may be used after it has been established that such a column is capable of separating all major impurities and the internal standard from the styrene under operating conditions appropriate for the column (see Practice E 1510). 5.3 Electronic Integration, with tangent capabilities is recommended. 5.4 lO0-mL Volumetric Flask. 5.5 Microsyringes, assorted volumes. TABLE 1

Typical Instrument Parameters

Carder gas Carder gas flow rate at 110oC, mL/m=n

Detector Detector temperature, oC Injection port temperature, °C Hydrogen flow rate, mL/min Air flow rate, mL/min

J This test method is under the jurisdiction of ASTM Committee D-16 on Aromatic Hydrocarbons and Related Chemicals and is the direct responsibility of Subcommittee DI6.OH on Styrene, Ethylbenzene, and C9 and Cjo Aromatic Hydrocarbons. Current edition approved May 15, 1995. Published July 1995. Originally published as D 5135 - 90. Last previous edition D 5135 - 93. 2 Annual Book of A S T M Standards, Vol 06.04. 3 Annual Book of ASTM Standards, Vol 14.02. 4 Available from Superintendent of Documents, U.S. Government Printing Office, Washington, DC 20402.

Make up gas Make up gas flow rate, mL/min Split flow, mL/min Column Column temperature, oC Chart speed, cm/min Sample size, BL

797

helium 1.2 flame ionization 240 230 30 275 nitrogen 23 150 60 m x 0.32 mm ID x 0.5 pm bonded polyethylene glycolfused silica capitlary 110 1 0.6

o s

Ash = area of internal standard in styrene used in making calibration mixture, Ab = area of impurity in styrene used to make calibration mixture, C~ = weight percent internal standard in calibration mixture, and Ct = weight percent impurity in calibration mixture.

6. Hazards 6.1 Consult the latest OSHA regulations, suppliers' Material Safety Data Sheets, and local regulations for all materials used in this procedure. 7. Reagents and Materials 7.1 Carrier Gas--a carder gas (minimum purity of 99.95 mol %) appropriate to the type of detector used should be employed. Precaution--If hydrogen is used, take special safety precautions to ensure that the system is free of leaks and that the effluent is properly vented or burned. 7.2 Hydrogen and air for the flame ionization detector

10. Sample Preparation 10.1 Establish stable instrument operation at the prescribed or selected operating conditions. Reference should be made to instructions provided by the manufacturer of the chromatograph. 10.2 Prepare sample as described in 9.2. 10.3 Inject appropriate amount of sample into the chromatograph and obtain the chromatogram. A typical chromatogram is shown in Fig. 1.

(~D). 7.3 n-Heptane, 99.0 % minimum purity, or other internal standard, such as n-octane, previously analyzed to be free of compounds coeluting with impurities in the sample. 7.4 Styrene, the highest purity available, but not less than 99.6 % as determined by freezing point. 7.5 Pure Compounds for calibration, shall be those compounds that are typically present in commercial styrene. These should be at least 99 % pure as they are to be used for determining response factors.

11. Calculation 11.1 Measure the areas of all peaks, including the internal standard, except the styrene peak. 11.2 Calculate the weight percent of the individual impurities, Ci, as follows:

(A~)(RF0 (Cs)

8. Sampling 8.1 Sample the material in accordance with Practice D 3437.

i

A,

where: Ai = area of impurity, As = area of internal standard, RFi = response factor for impurity, relative to the internal standard, and Cs = concentration of internal standard, in weight percent. 11.3 Calculate the styrene content by subtracting the sum of the impurities from 100.00. Styrene weight percent = 100.00 - (sum of impurities).

9. Procedure 9.1 Prepare a calibration mixture containing approximately 99.5 weight % styrene and the expected significant impurities at their expected concentration. Weigh all components to the accuracy required to calculate the concentration of each to the nearest 0.001%. 9.2 With a microsyringe, add 50 gL of internal standard to a 100-mL volumetric flask about three-fourths full of the calibration mixture. Mix well. Add calibration mixture to mark and again mix well. If n-heptane is used as the internal standard, using a density of 0.684 for n-heptane and 0.906 for styrene, this solution will contain 0.0377 weight % n-heptane. 9.3 Also prepare a sample of the styrene used for the calibration blend with and without n-heptane to determine the concentration of existing impurities and interfering compounds with internal standard. If impurities in the styrene emerge with the chosen internal standard, an alternate internal standard must be used. 9.4 Inject an appropriate amount of sample into the chromatograph and obtain a chromatogram. 9.5 Measure the areas of all peaks, including the internal standard, except the styrene peak. 9.6 Calculate the response factors for each impurity relative to the internal standard as follows:

RFi=

zs

12. Report 12.1 Report the concentration of impurities to the nearest 0.001% and the styrene content to the nearest 0.01%. 13. Precision and Bias 13.1 Precision--The following criteria should be used to judge the acceptability (95 % probability level) of results obtained by this test method. The criteria were derived from a round robin among six laboratories. The data were run on two days using different operators. 13.2 IntermediatePrecision--Results in the same laboratory should not be considered suspect unless they differ by more than the normal amount shown in Table 2 and 2A. 13.3 Reproducibility--The results by each of two laboratories should not be considered suspect unless they differ by more than the amount shown in Table 2 and 2A. 13.4 No statement is made about bias since no acceptable reference material and value is available.

Ci

where:

14. Keywords 14.1 analysis by gas chromatography; impurities in styrene; purity of styrene; styrene; styrene monomer

RF~ = response factor relative to the internal standard, As~ = area of internal standard in calibration mixture, A~ = area of impurity peak in calibration mixture,

798

(~)

O 5135

14.40

S Ln

X "13 O/ ET) L o

12. 45

,10. 5;

9.5~

6. B5 o_

4,71

RES3~J58

o, oo

minutes

1.87

3. 75

5, 62

7.50

g. 37

1!, 25

13. 12

15, O0

SAMPLE= STYRENE WITH N-HEPTANE ISTD ANALYZED= Thu Nov 15, 1990 9:43:06 om RESULT= /RESULT/RES3 159. RES METHOD=GFPA FIG. 1 TABLE 2

Typical Chrometogrem (see Table 1)

Precision for Styrene end Impurities at Stated Levels

Component Styrene Ethylbenzene <x-methylstyrene Isopropy[benzene n-propylbenzene m- and ,o-ethyltoluene p, m-xylene o-xylene

TABLE 2A

Stated Levels

Concentration, Intermediate weight ~ Precision, Reproducibility, % % 99.74 0.043 0.028 0.008 0.004 0.014 0.125 0.030

0.017 0.002 0.0001 0.001 0.0003 0.001 0.005 0.001

Pr~ision for High Purity Styrene and Impurities at

Component

0.054 0.001 0.004 0.001 0.001 0.005 0.007 0.042

Styrene Ethylbenzene <~-methylstyrane

Concentration, Intermediate weight % Precision, Reproducibility, 99,96 0.014 O.007

%

%

0.024 0.003 0.002

0~033 0.004 0.003

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility, This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and ff not revised, either reepproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at e meeting of the responsible technical committee, which you may attend, ff you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103,

799

(~

Designation:D 5185 - 97

An American Natkmal Standard

Standard Test Method for Determination of Additive Elements, Wear Metals, and Contaminants in Used Lubricating Oils and Determination of Selected Elements in Base Oils by Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES) This standard is issued under the fixed designation D 5185; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (0 indicates an editorial change since the last revision or rcapproval.

INTRODUCI]ON Costs associated with maintenance due to engine and machine wear can be significant. Therefore, diagnostic methods for determining the condition of engines and other machinery can be important. This test method is intended to quantify, for the purpose of equipment monitoring the concentration of metals in used lubricating oils. Although the precision statement was determined by analyzing a variety of used oils this test method can, in principle, be used for the analysis of unused oils to provide more complete elemental composition data than Test Methods D 4628, D 4927 or D 4951. 1. Scope 1.1 This test method covers the determination of additive elements, wear metals, and contaminants in used lubricating oils by inductively coupled plasma atomic emission spectrometry (ICP-AES). The specific elements are listed in Table 1. 1.2 This test method covers the determination of selected elements, listed in Table 1, in re-refined and virgin base oils. 1.3 For analysis of any element using wavelengths below 190 nm, a vacuum or inert-gas optical path is required. The determination of sodium and potassium is not possible on some instruments having a limited spectral range. 1.4 This test method uses oil-soluble metals for calibration and does not purport to quantitatively determine insoluble particulates. Analytical results are particle size dependent, and low results are obtained for particles larger than a few micrometers. 2 1.5 Elements present at concentrations above the upper limit of the calibration curves can be determined with additional, appropriate dilutions and with no degradation of precision. 1.6 For elements other than calcium, sulfur, and zinc, the low limits listed in Tables 2 and 4 were estimated to be ten times the repeatability standard deviation. For calcium, sulfur, and zinc, the low limits represent the lowest concentrations tested in the inteflaboratory study. 1.7 The values stated in SI (metric) units are to be regarded as the standard. The inch-pound units #oven in l This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.03.0B on Spectrometric Methods. Current edition approved Apr. 10, 1997. Published October 1997. Originally published as D 5185 - 91. Last previous edition D 5185 - 95. 2 Eisentraut, K. J., Newman, R. W., Saba, C. S., Kauffman, R. E., and Rhine, W. E., Analytical Chemistry, Vol 56, 1984.

parentheses are for information only. 1.8 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Specific precautionary statements are #oven in Notes 1, 2, and 3. 2. Referenced Documents

2.1 ASTM Standards: C 1109 Test Method for Analysis of Aqueous Leachates from Nuclear Waste Materials Using Inductively Coupled Plasma-Atomic Emission Spectrometry3 D 1552 Test Method for Sulfur in Petroleum Products (High-Temperature Method)4 D 4057 Practice for Manual Sampling of Petroleum and Petroleum Products5 D 4307 Practice for Preparation of Liquid Blends for Use as Analytical Standards 5 D4628 Test Method for Analysis of Barium, Calcium, Magnesium, and Zinc in Unused Lubricating Oils by Atomic Absorption Spectrometry 5 D 4927 Test Methods for Elemental Analysis of Lubricant and Additive Components---Barium, Calcium, Phosphorus, Sulfur, and Zinc by Wavelength-Dispersive X-Ray Fluorescence Spectroscopy6 D4951 Test Method for Determination of Additive Elements in Lubricating Oils by Inductively Coupled Plasma Atomic Emission Spectrometry6 3 Annual Book of ASTM 4 Annual Book of ASTM s Annual Book of ASTM 6 Annual Book of ASTM

800

Standards, Standards, Standards, Standards,

Vol 12.01. Vol 05.01. Voi 05,02. Vo| 05.03.

fl~ D 5185 TABLE 1

E 135 Terminology Relating to Analytical Chemistry for Metals, Ores, and Related Materials 7

Aluminum Barium Boron Calcium Chromium Copper Iron Lead Magnesium Manganese Molybdenum Nickel Phosphorus Potassium Sodium Silicon Silver Sulfur Tin Titanium Vanadium Zinc

3. Terminology 3.1 Definitions: 3.1.1 emission spectroscopy--refer to Terminology E 135.

3.2 Definitions of Terms Specific to This Standard: 3.2.1 additive element--a constituent of a chemical compound that improves the performance of a lubricating oil. 3.2.2 analyte--an element whose concentration is being determined. 3.2.3 Babington-type nebulizer--a device that generates an aerosol by flowing a liquid over a surface that contains an orifice from which gas flows at a high velocity. 3.2.4 calibration--the process by which the relationship between signal intensity and elemental concentration is determined for a specific element analysis. 3.2.5 calibration curve--the plot of signal intensity versus elemental concentration using data obtained by making measurements with standards. 3.2.6 contaminant--a foreign substance, generally undesirable, introduced into a lubricating off. 3.2.7 detection limit--the concentration of an analyte that results in a signal intensity that is some multiple (typically two) times the standard deviation of the background intensity at the measurement wavelength. 3.2.8 inductively-coupled plasma (ICP)--a high-temperature discharge generated by flowing an ionizable gas through a magnetic field induced by a load coil that surrounds the tubes carrying the gas. 3.2.9 linear response range--the elemental concentration range over which the calibration curve is a straight line, within the precision of the test method. 3.2.10 profiling--a technique that determines the wavelength for which the signal intensity measured for a particular analyte is a maximum. 3.2.11 radio frequency (RF)--the range of frequencies between the audio and infrared ranges (3 kHz to 300 GHz). 3.2.12 wear metaluan element introduced into the oil by wear of oil-wetted parts. 4. Summary of Test Method 4.1 A weighed portion of a thoroughly homogenized used oil is diluted ten-fold by weight with mixed xylenes or other suitable solvent. Standards are prepared in the same manner. An optional internal standard can be added to the solutions to compensate for variations in test specimen introduction efficiency. The solutions are introduced to the ICP instrument by free aspiration or an optional peristaltic pump. By comparing emission intensities of elements in the test specimen with emission intensities measured with the standards, the concentrations of elements in the test specimen are calculable.

Elements Determined and Suggested Wavelengths ~

Element

Wavelength, nm 308.22, 396.15, 309.27 233.53, 455.40, 493.41 249.77 315.89, 317.93, 364.44, 422.67 205.55, 267.72 324.75 259.94, 238.20 220.35 279.08, 279.55, 285.21 257.61,293.31,293.93 202.03, 281.62 231.60, 277.02, 221.65 177.51,178.29, 213.62, 214.91,253.40 766.49 589.59 288.16, 251.61 328.07 180.73, 182.04, 182.62 189.99, 242.95 337.28, 350.50, 334.94 292.40, 309.31,310.23, 311.07 202.55, 206.20, 313.86, 334.58, 481.05

A These wavelengths are only suggested and do not represent all possible choices.

Test times approximate a few minutes per test specimen, and detectability for most elements is in the low mg/kg range. In addition, this test method covers a wide variety of metals in virgin and re-refined base oils. Twenty-two elements can be determined rapidly, with test times approximating several minutes per test specimen. 5.2 When the predominant source of additive elements in used lubricating oils is the additive package, significant differences between the concentrations of the additive elements and their respective specifications can indicate that the incorrect oil is being used. The concentrations of wear metals can be indicative of abnormal wear if there are baseline concentration data for comparison. A marked increase in boron, sodium, or potassium levels can be indicative of contamination as a result of coolant leakage in the equipment. This test method can be used to monitor equipment condition and define when corrective actions are needed. 5.3 The concentrations of metals in re-refined base oils can be indicative of the efficiency of the re-refining process. This test method can be used to determine if the base oil meets specifications with respect to metal content. 6. Interferences 6.1 Spectral--Check all spectral interferences expected from the elements listed in Table 1. Follow the manufacturer's operating guide to develop and apply correction factors to compensate for the interferences. To apply interference corrections, all concentrations must be within the previously established linear response range of each element listed in Table 1. NOTE h Caution---Correct profiling is important to reveal spectral

5. Significance and Use 5.1 This test method covers the rapid determination of 22 elements in used lubricating oils and in base oils, and it provides rapid screening of used oils for indications of wear.

interferences from high concentrations of additive elements on the spectral lines used for determining wear metals. 6.1.1 Spectral interferences can usually be avoided by judicious choice of analytical wavelengths. When spectral interferences cannot be avoided, the necessary corrections should be made using the computer software supplied by the

7 Annual Book of A S T M Standards, Vol 03.05.

801

~) D 5185 instrument manufacturer or the empirical method described below. Details of the empirical method are given in Test Method C 1109 and by Boumans. s This empirical correction method cannot be used with scanning spectrometer systems when both the analytical and interfering lines cannot be located precisely and reproducibly. With any instrument, the analyst must always be alert to the possible presence of unexpected elements producing interfering spectral lines. 6.1.2 The empirical method of spectral interference correction uses interference correction factors. These factors are determined by analyzing the single-element, high-purity solutions under conditions matching as closely as possible those used for test specimen analysis. Unless plasma conditions can be accurately reproduced from day to day, or for longer periods, interference correction factors found to affect the results significantly must be redetermined each time specimens are analyzed. 6.1.3 Interference correction factors, Kia, are defined as follows: For anaiyte a, we have: Ca = Ia/Ha (1) where: Ca = concentration of analyte a, Ia ffi net line intensity (that is, background corrected) of analyte a, and Ha ffi sensitivity. 6.1.3.1 Similarly, for an interferent i at the same wavelength: Ci = Ii/Hi (2) where: Ii = contribution from the peak or wing of the interferent line to the peak intensity of the analyte a. 6.1.3.2 The correction factor, Kia is defined as: Kia = Hi~Ha - li/(Ci × Ha) (3) 6.1.3.3 Analysis of high-purity stock solutions with a calibrated instrument gives Ii/Ha, the concentration error that results when analyzing a solution containing an interferent of concentration Ci. Dividing by Ci gives the dimensionless correction factor Kia. To apply these correction factors: Ca, apparent ffi (Ia + IO/Ha (4) Ca, apparent -- Ca + Ii/Ha (5) Ca = Ca, apparent - li/Ha (6) Ca Ca, apparent - Kia * Ci (7) and, for more than one interferent: Ca Ca, apparent - Kla x CI - K2a x C2 - . . . (8)

affect the accuracy of the analysis. The effects can be reduced by using a peristaltic pump to deliver solutions to the nebulizer or by the use of internal standardization, or both. When severe viscosity effects are encountered, dilute the test specimen and standard 20-fold rather than 10-fold while maintaining the same concentration of the internal standard. 6.3 Particulates--Particulates can plug the nebulizer thereby causing low results. Use of a Babington type highsolids nebulizer helps to minimize this effect. Also, the specimen introduction system can limit the transport of particulates, and the plasma can incompletely atomize particulates, thereby causing low results.

7. Apparatus 7.1 Balance, top loading, with automatic tare, capable of weighing to 0.001 g, capacity of 150 g. 7.2 Inductively-Coupled Plasma Atomic Emission Spectrometer--Either a sequential or simultaneous spectrometer is suitable, if equipped with a quartz ICP torch and RF generator to form and sustain the plasma. Suggested wavelengths for the determination of the elements in used oils are given in Table 1. For the analysis of sulfur, the spectrometer must be capable of operating in the wavelength region of 180 rim.

7.3 Nebulizer--A Babington-type9,~° high-solids nebulizer is strongly recommended. This type of nebulizer reduces the possibility of clogging and minimizes aerosol particle effects. 7.4 Peristaltic Pump, (Recommended)--A peristaltic pump is strongly recommended to provide a constant flow of solution. The pumping speed must be in the range 0.5 to 3 mL/min. The pump tubing must be able to withstand at least 6 h exposure to the dilution solvent. Viton tubing is typically used with hydrocarbon solvents, and poly-vinyl chloride tubing is typically used with methyl isobutyl ketone. 7.5 Solvent Dispenser, (Optional)--A solvent dispenser calibrated to deliver the required weight of dilution solvent for a ten-fold dilution of test specimen is very useful. 7.6 Specimen Solution Containers, 30 to 120 mL (1 to 4 oz.), glass or plastic vials or bottles, with screw caps. 7.7 Ultrasonic Homogenizer, (Recommended)--A bathtype or probe-type ultrasonic homogenizer to homogenize the sample. 7.8 Vortexer, (Optional)--Vortexing the sample is an alternative to ultrasonic homogenization.

8. Reagents and Materials

ffi

8.1 Purity of Reagents--Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society where such specifications are available?' Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without

ffi

6.1.4 Interference correction factors can be negative if off-peak background correction is employed for element i. A negative Kia can result when an interfering line is encountered at the background correction wavelength rather than at the peak wavelength. 6.2 Viscosity Effects--Differences in the viscosities of test specimen solutions and standard solutions can cause differences in the uptake rates. These differences can adversely

9 Babington, R. S., PopularScience, May 1973, p. 102. t° Fry, R. C. and Denton, M. B., Analytical Chemistry, Vol 49, 1977. it Reagent Chemicals, American Chemical Society Spec(ficatioas, American Chemical Society, Washington, DC. For sugsestions on the testin8 of reagents n o t listed by the American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville, MD.

s Boumans, P. W. J. M., "Corrections for Spectral Interferences in Optical Emission Spectrometry with Special Reference to the RF Inductively Coupled Plasma," SpectrochimicaActa, 1976, Vol 31B, pp. 147-152.

802

~

D 5185 10. Sampling 10.1 The objective of sampling is to obtain a test specimen that is representative of the entire quantity. Thus, take lab samples in accordance with the instructions in Practice D 4057. The specific sampling technique can affect the accuracy of this test method.

lessening the accuracy of the determination. 8.2 Base Oil--U.S.P. white oil, or a lubricating base oil that is free of analytes, and having a viscosity at room temperature as close as possible to that of the samples to be analyzed. NOTS 2: Caution--Lubricating base oils contain sulfur. For sulfur determinations, white oil is recommended for the preparation of standards.

11. Sample Handling 11.1 Homogenizationmlt is extremely important to homogenize the used oil in the sample container in order to obtain a representative test specimen. 11.2 Ultrasonic Homogenization--Place the used oil (in the sample container) into the ultrasonic bath. For very viscous oils, first heat the sample to 60"C. Leave the sample in the bath until immediately before dilution. 11.3 Vortex Homogenization--As an alternative to ultrasonic homogenization, vortex mix the used oil in the sample container, if possible. For viscous oils, first heat the sample to 60"C.

8.3 Internal Standard--Oil-soluble cadmium, cobalt, or yttrium are required when the internal standardization option is selected. 8.40rganometallic Standards--Multi-element standards, containing 0.0500 mass % of each element, can be prepared from the individual concentrates. Refer to Practice D 4307 for a procedure for preparation of multicomponent liquid blends. When preparing multi-element standards, be certain that proper mixing is achieved. An ultrasonic bath is recommended. Standard multi-element concentrates, conraining 0.0500 mass % of each element, are also satisfactory. Nots 3: Caution--Some commercially available organometallic standards are prepared from metal sulfonatesand thereforecontain sulfur.For sulfurdeterminations,a separatesulfurstandard would be required. NOTS 4--Secondary standardssuch as those prepared from petroleum additives,for example, can be used in placeof those described.~ if the use of such secondarystandardsdoes not affectthe analyticalresults by more than the repeatabilityof thistestmethod. 8.5 SulfurStandardDTo use a metal sulfonate as a sulfur standard, analyze the sulfonatc by Test Method D 1552. Alternatively, prepare a sulfur standard by diluting N I S T S R M 1622c 12 in white oil. 8.6 Dilution Solvent--A solvent that is free of analytcs and is capable of completely dissolving all standards and samples. Mixed xylencs, kerosine, and ortho-xylene were successfully used as dilution solvents in the interlaboratory study on precision.

9. Internal Standardization (Optional) 9.1 The internal standard procedure requires that every test specimen solution have the same concentration (or a known concentration) of an internal standard element that is not present in the original specimen. Specimen to specimen changes in the emission intensity of the internal standard element can be used to correct for variations in the test specimen introduction efficiency, which is dependent on the physical properties of the test specimen. 9.2 Internal Standard Solution--Weigh 20 g of 0.500 mass % cadmium, cobalt, or yttrium (or any other suitable metal) organometallic concentrate into a 1 L volumetric flask and dilute to 1 L with the dilution solvent. Prepare fresh, at least weekly, and transfer this solution into a dispensing vessel. The concentration of the internal standard element is not required to be 100 btg/mL; however, the concentration of the internal standard element in the test specimen solution should be at least 100 times its detection limit. 12Available from the National Institute of Standards and Technology, Gaithersburg, MD 20899.

803

12. Preparation of Test Specimens and Standards 12.1 Blank--Prepare a blank by diluting the base oil or white oil ten-fold by mass with the dilution solvent. 12.2 Working Standard, 10 ixg/mL--Weigh 2 g of the 0.0500 mass % multi-element standard into a 4-oz. glass bottle, add 8 g of base oil and dilute with 90 g of dilution solvent. Working standards containing higher or lower concentrations can be prepared depending on the concentrations of additive elements, wear metals, or contaminants in the used oils. In addition, solutions containing single elements can also be prepared. However, ensure that the ten-fold dilution is maintained for all solutions. 12.3 Check Standards--Prepare instrument check standards in the same manner as the working standards such that the concentrations of elements in the check standards are similar to the concentrations of elements in the specimens, 12.4 Test Specimen--Weigh a portion of the weU-homogenized sample into a suitable container, Add dilution solvent until the test specimen concentration is I0 mass %. 12.5 Internal Standard--If an internal standard is being used, add internal standard solution to the working standard, check standard, and test specimen before diluting with the dilution solvent. Ensure that the standard or test specimen concentration is 10 mass %. Alternatively, the internal standard can be present in the dilution solvent.

13. Preparation of Apparatus 13.1 Instrument--Design differences between instruments, ICP excitation sources, and different selected analytical wavelengths for individual spectrometers make it impractical to detail the operating conditions. Consult the manufacturer's instructions for operating the instrument with organic solvents. Set up the instrument for use with the particular dilution solvent chosen. 13.2 Peristaltic Pump----If a peristaltic pump is used, inspect the pump tubing and replace it, if necessary, before starting each day. Verify the solution uptake rate and adjust it to the desired rate. 13.3 ICP Excitation Source--Initiate the plasma source at least 30 rain before performing analysis. During this warm up period, nebulize dilution solvent. Inspect the torch for

~

D 5185 concentrations can be performed manually or by computer when such a feature is available. 15.2 Quality Control with Check Standard--Analyze the check standard after every fifth sample, and if any result is not within 5 % of the expected concentration, recalibrate the instrument and reanalyze the test specimens solutions back to the previous acceptable check standard analysis.

carbon bu•-up during the warm up period. If carbon build-up occurs, replace the torch immediately and consult the manufacturer's operating guide to take proper steps to remedy the situation. NOTE 5--Some manufacturers recommend even longer warm-up periods to minimize changes in the slopes of calibration curves.

13.4 Wavelength Profiling--Perform any wavelength profding that may be called for in the normal operation of the instrument. 13.5 Operating Parameters--Assign the appropriate operating parameters to the instrument task file so that the desired elements can be determined. Parameters to be included are element, wavelength, background correction points (optional), interelement correction factors (optional), integration time, and internal standard correction (optional). Multiple integrations are required for each measurement, and the integration time is typically 10 s.

NOTe 6 - - T o verify the accuracy and precision of the instrument calibration, certified standards such as SRM 1085) 3 should be regularly

analyzed. 15.3 Analysis with Internal Standardization--Analyze the test specimen solutions and calculate an intensity ratio for each of the elements found in the test specimen solutions using Eq. 9 given in 14.3. From these intensity ratios, concentrations of the elements can be calculated.

14. Calibration 14.1 The linear range must be established once for the particular instrument being used. This is accomplished by running intermediate standards between the blank and the working standard and by running standards containing higher concentrations than the working standard. Analyses of test specimen solutions must be performed within the linear range of response. 14.2 Working Standard--At the beginning of the analysis of each batch of specimens, perform a two-point calibration consisting of the blank and working standard. Use the check standard to determine if each element is in calibration. When the results obtained with the check standard are within 5 % of the expected concentrations for all elements, proceed with test specimen analyses. Otherwise, make any adjustments to the instrument that are necessary and repeat the calibration. Repeat this procedure with the check standard every five samples. 14.3 Working Standard with Internal Standard--Calibrate the instrument as described in 14.2. Obtain a printed record of the standard's emission intensities and those of the internal standard. Calculate an intensity ratio for each element by the following equation: I(Re) + (l(e) - I(Be))/I(is) (9) where: I(Re) = intensity ratio for element e, I(e) = intensity for element e, I(Be) = intensity of the blank for element e, and I(is) = intensity of internal standard element. 14.3.1 Calculate the calibration factors from the intensity ratios. Alternatively, use the computer programs provided by the instrument's manufacturer to calibrate the instrument using internal standardization. 15. Procedure and Calculation

15.1 Analysis--Analyze the test specimen solutions in the same manner as the calibration standards (that is, same integration time, background correction points, plasma conditions, etc.). Between test specimens, nebulize dilution solvent for 60 s. Calculate elemental concentrations by multiplying the determined concentration in the diluted test specimen solution by the dilution factor. Calculation of

16. Report 16.1 Report mg/kg to three significant figures for calcium, magnesium, zinc, barium, phosphorus, and sulfur. Report mg/kg to two significant figures for aluminum, boron, chromium, copper, iron, lead, manganese, molybdenum, nickel, potassium, sodium, silicon, silver, tin, titanium and vanadium. 17. Precision and Bias z3

17.1 Precision--The precision of this test method was determined by statistical analysis of inteflaboratory results. In this study, dilution solvents were limited to xylene or kerosine. Some laboratories chose to use Babington-type nebulizers, peristaltic pumps, and background correction. Fourteen laboratories analyzed twelve specimens in duplicate. The samples were: one gas turbine used oil, four gasoline engine used oils, two truck diesel engine used oils, two marine engine used oils, SRM 1085 t4 diluted in SRM 108312 (base oil) to contain approximately 40 mg/kg of eleven different metals (this oil also contained 8 mass % of an ethylene-propylene copolymer viscosity index improver), SRM 1085 diluted in SRM 1083 to contain approximately 40 mg/kg of twelve different metals, SRM 1085 diluted in SRM 1083 to contain approximately 2 mg/kg of 12 different metals. 17.1.1 Repeatability--The difference between two test results, obtained by the same operator with the same apparatus under constant operating conditions on identical test material would, in the long run, in the normal and correct operation of the test method, exceed the values in Tables 2 and 3 only in one case in twenty. 17.1.2 Reproducibility--The difference between two single and independent results, obtained by different operators working in different laboratories on identical test materials, would in the long run, in the normal and correct operation of the test method, exceed the values in Tables 4 and 5 only in one case in twenty. 17.1.3 Parametric representations of precision, calculated separately for the set of three base oil dilutions ofNIST SRM ~3Interlaboratory study data are available from ASTM Headquarters. Request RR:D02- ! 282. t4 Winge, R. K., Fassel, V. A., Peterson, V. J., and Floyd, M. A., Inductively

Coupled Plasma-AtomicEmission Spectroscopy:An Atlas of Spectral Information, Elsevier, New York, 1985.

804

lib D 5185 TABLE 2 Repeatablllty

TABLE 4

F.km~mt

Range, r n ~

Aluminum Badum Boron C.,ak:lum CNomlum

6-40 0.5-4 4-3O 40--9000 1-40

0.71 0.24 o.2e 0.0020 0.17

X°.41 XT M X X 1.4 Xo.v6

iron I._,~_

2-160 2-140 10-150

0.12 0.13 1.6

X °'el X° J °

5-1700 5-700 5-200 5-40 10-1000 40-1200 8-50 0.5-50

X°'a~ 0.16 XT M 0.010 X 1~1 0.29 Xo.vo 0.52 X°-'w 1.3 XT M 3.8 Xo-a8 1.3 X°-~ 0.16 Xo'~

Sodium

7-70

0.49

X°.m

Sulfur Tin Titanium Vanadkjm

900-6000 10-40 5,-40 1-50

0.49 2.4 0.54

X°.~v

Xo-~

0.061 0.15

X XTM

Magneqdum Molytxkmum Nk:kel Pho~ Potaulum Silicon

60-1600

TABLE 3 CalcuMtedRepealabUlty (pglg) at 8elected conoan~raUmm (mo/kg) OonmnU'mkm

/ulmmum Badum Boron

1

10

...

1.6

.

iii

ile

...... "i'

"ii

100

...

CI¢om~m

.. .. .. ..

Iron Lud M

W

Sak:on

Silver Sodium Sulfur

"nn Titank~ Vanadium

Z~nc

1.0 0.8 3.3 1.2 0.2 1.5 1.6

.. •. ...

.

.

.

10

6.6

100 .

.

2.4

24

7 0 4 7

61 ... ...

3.3 6.9 4.2

21 16 25

2.1 3.3 4.7 14

33 17

Manganese Mo~ybde,um

o.

Pho~txxus

... .

2.2 .

. . ...

17

.

.

.

Potassium Sik:on Saver Sodium Sulfur Tin 11tanium Vanadium Zinc

37 .

.

. . °

130 . . . . . . . . . . . .

6

65

1000 .

.

.

.

o , .

Iron I___a9~1_ Magnesium

1.0

.

1 Nt,fnlnum Barium Boron

Copper

():i

.

X°.2a X°.~ X°.°1 X 1-s X0.61 X X°-e° XT M Xo'?? X 1= X°-7~ X° ' ~ X°-e° X°-~) X°.ae X X°'71 X°'?e Xo.~ X°'47 X 1"1 X 1"1

Ccxcantmtkm

Element

Chronta~

. . . . . .

.

1.5 4.3 6.6 2.9 0.35 1.1 1.2 2.1 2.5 0.28 0.083

... ...

";9

.

0.64

..

4.9

1.3 o.0

3.8 0.59 13 0.015 0.81 0.24 0.52 3.0 0.72 0.13

C a l c u l a t e d Reproducibility ( p g / g ) a t f ~ d e c t e d Concentrations (mg/kg)

Nickel

.

Reproducibility, pg/O A

8 5

il;

o:i . .

TABLE 5

.

...

.

6-40 0.5-4 4-30 40-9000 1-40 2--160 2-140 10-160 5-1700 5-700 5-200 5-40 10-1000 40-1200 8-50 5-50 7-70 900-6000 10-40 5-40 1-50 60-1600

1000 .

"'"

.

Aluminum Barium Boron Cak~um Chromium

Where: X - mean corcentratton, 1~O-

'* Where: X - mmn ¢onoen~tlon, l~g/g.

Boment

Range, mg/kg

Iron Lead Magnesium Manganese Molybdenum Nickel Phosphorus Potassium Sllk:on Silver Sodium Sulfur Tin Titanium Vanadium Zinc

Xo-*~

Reproducibility

Element

Repeated:dllty, i ~ g '~

;):4

7.1 3.5 5.6

43 25

8.8 7A 3.5 ...

150 ...

... 140 49

. . . . . . . . . . . . ... ...

, o .

... ...

210

. . . . . . . . . . . . 13

170

cant interferences from other elements exist (see 6.1).

1085, are essentially the ~me, within experimental error, as the precision listed in Tables 2 and 4, 17.2 Bias--Bias was evaluated by analyzing quantitative dilutions of SRM 1085, that contains off-soluble metals rather than insoluble particulates. The means of the reported values for AI, Cr, Cu, Fe, Pb, M& Mo, Ni, Si, A8, Sn, and Ti do not differ from the corresponding expected values by more than the repeatability of the method, when no signifi.

18. Ke~,ords

18.1 additive-elements; aluminum; barium; boron; calcium; chromium; copper, emi~sion-~ometry; ICP; inductively coupled plasma atomic emission spectrometry; iron; lead; lubricating oils; magnesium; manganese; molybdenum; nickel; phosphorous, potassium; silicon; silver; sodium; sulfur;,tin; titanium; vanadium; wear metals; zinc

Tbe American Socisty for Thating and MaterIs~ fakee n~ p~sit~n respecting tbe v~ldity of any patont rights ~ssOrtedIn ~onect~n w#lt any Item mentioned in this ~ . Users of this standard are expressly advised that determination of the validity of any such patent rights, and the ~ of I t ) f ~ of such rights, are entirely their Own r"~ponsibllity. This standard Is subJ~t to revision at any time by the responsible technlcsi committee and must be reviewed every five years and if not revised, either rupproved or withdrawn. Yourcomments are Invited either for revision of this standard Or for additional standards and should be addressed to ASTM Headquarters, Your ~ will receive careful consideration at a meeting of the responsible technloal committee, which you may attend. If you feel that your comments have not reGeived a fair hearing you should make your views known to the ASTM Committee on Standards, 100 Ban" Har~xx"Dr/re, West Conshohockan, PA 19428.

805

(~)

Designation: D 5186 - 96 Standard Test Method for Determination of the Aromatic Content and Polynuclear Aromatic Content of Diesel Fuels and Aviation Turbine Fuels By Supercritical Fluid Chromatography 1 This standard is issued under the fixed designation D 5186; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last re,approval. A superscript epsilon (() indicates an editorial change since the last revision or reapproval.

1. Scope 1.1 This test method covers the determination of the total amounts of monoaromatic and polynuclear aromatic hydrocarbon compounds in motor diesel fuels, aviation turbine fuels, and blend stocks by supercritical fluid chromatography (SFC). The range of aromatics concentration to which this test method is applicable is from 1 to 75 mass %. The range of polynuclear aromatic hydrocarbon concentrations to which this test method is applicable is from 0.5 to 50 mass %. 1.2 The values stated in SI units are to be regarded as standard. The values stated in inch-pound units are for information only. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use, It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

carbon compounds containing two or more aromatic rings. These rings may be fused as in naphthalene and phen. anthrene, or separate as in biphenyl. 3.1.5 restrictor, n--a device, attached to the outlet of a chromatographic column, to restrict the mobile phase flow such that the mobile phase is maintained in the supercritical state throughout the chromatographic column. 3.1.6 supercriticalfluid, n--a fluid maintained in a thermodynamic state above its critical temperature and critical pressure. 3.1.7 supercritical fluid chromatography, n--a class of chromatography that employs supcrcritical fluids as mobile phases.

4. Summary of Test Method 4.1 A small aliquot of the fuel sample is injected onto a packed silica adsorption column and eluted using supercritical carbon dioxide mobile phase. Monoaromatics and polynuclear aromatics in the sample are separated from nonaromatics and detected using a flame ionization detector. 4.2 The detector response to hydrocarbons is recorded throughout the analysis time. The chromatographic areas corresponding to the monoaromatic, polynuclear aromatic, and nonaromatic components are determined and the mass % content of each of these groups in the fuel is calculated by area normalization.

2. Referenced Documents

2.1 A S T M Standards: D1319 Test Method for Hydrocarbon Types in Liquid Petroleum Products by Fluorescent Indicator Adsorption 2 D 1655 Specification for Aviation Turbine Fuels2 D 2425 Test Method for Hydrocarbon Types in Middle Distillates by Mass Spectrometry2

5. Significance and Use 5.1 The aromatic hydrocarbon content of motor diesel fuels is a factor which can affect their cetane number and exhaust emissions. The aromatic hydrocarbon content and the naphthalenes content of aviation turbine fuels affects their combustion characteristics and smoke-forming tendencies. These properties represent specifications for aviation turbine fuels (Specification D 1655). 5.2 The United States Environmental Protection Agency (USEPA) regulates the aromatic content of diesel fuels. California Air Resources Board (CARB) regulations place limits on the total aromatics content and polynuclear aromatic hydrocarbon content of motor diesel fuel, thus requiting an appropriate analytical determination to ensure compliance with the regulations. Producers of diesel fuels will require similar determinations for process and quality control. This test method can be used to make such determinations. 5.3 This test method is applicable to materials in the boiling range of motor diesel fuels and is unaffected by fuel

3. Terminology 3.1 Definitions of Terms Specific to This Standard." 3.1.1 critical pressure, n--that pressure needed to condense a gas at the critical temperature. 3.1.2 critical temperature, n--the highest temperature at which a gaseous fluid may be converted to a liquid by means of compression. 3.1.3 mononuclear aromatic hydrocarbons, nmhydrocarbon compounds containing exactly one aromatic ring. This group includes benzene, alkyl-substituted benzenes, indans, tetralins, alkyl-substituted indans, and alkyl-substituted tetralins. 3.1.4 polynuclear aromatic hydrocarbons, n--all hydro1 This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.04 on Hydrocarbon Analysis. Current edition approved April 10, 1996. Published June 1996. Originally published as D 5186- 91. Last previous edition D 5186 -91. 2 Annual Book of ASTM Standards, Vol 05.0 I.

806

~

D 5186

coloration. Test Method D 1319, which has been mandated by the USEPA for the determination of aromatics in motor diesel fuel, excludes materials with final boiling points greater than 315"C (600°1) from its scope. Test Method D 2425 is applicable to the determination of both total aromatics and polynuclear aromatic hydrocarbons in diesel fuel, but is much more costly and time-consuming to perform. 5.4 Results obtained by this test method have been shown to be statistically more precise than those obtained from Test Method D 1319 for typical diesel fuels, and this test method has a shorter analysis time. 3 Cooperative study data 4 has found this test method to be more precise than the published precision of Test Method D 1319 when applied to aviation turbine fuels and diesel fuels. Results from this test method for total polynuclear aromatic hydrocarbons are also expected to be at least as precise as those of Test Method D 2425.

6. Apparatus 6.1 Supercritical Fluid Chromatograph (SFC)--Any SFC instrumentation can be used that has the following capabilities and meets the performance requirements in Section 8. 6.1.1 Pump~The SFC instrumentation must include a pump capable of delivering supercritical carbon dioxide to the column, without pressure fluctuations, and at constant flow. The pump is typically a single-stroke-type (syringe) pump or a highly dampened reciprocating pump with pressure fluctuations not exceeding _+0.3 % of the operating pressure. 6.1.2 Detector--This test method is limited to the use of the flame ionization detector (FID). The detector must have sufficient sensitivity to detect 0.I mass % toluene in hexadecane under instrument conditions employed in this test method. 6.1.3 Column Temperature Control--The chromatograph must be capable of column temperature control of at least •+0.5°C (1°1) at the operating temperature. 6.1.4 Sample Inlet System--A liquid sample injection valve is required, capable of reproducibly introducing samples in the 0.05 to 0.50-~tL liquid volume range. The inlet system should be operated at between 25 and 30°C. The sample inlet system must be connected to the chromatographic column so that loss of chromatographic efficiency is avoided. 6.1.5 Post-column Restrictor--A device capable of mainraining mobile phase supercritical conditions within the column, and up to the detector inlet must be connected to the end of the column. 6.1.6 ColumnmAny liquid or supercritical fluid chromatographic column may be used that provides separation of nonaromatic, monoaromatic, and polynuclear aromatic hydrocarbons and meets the performance requirements of Section 8. Some columns and conditions, that have been used successfully are shown in Table 2. 6.1.7 IntegratorDMeans must be provided for the deter-

TABLE 1

Theoretical Response Factors

Component

Carbon Number

MolecularMass

RRFme

Toluene Tetralin Naphthalene

7 10 10

92.13 132.2 128.2

1.075 1,070 1.104

mination of both discrete chromatographic peak areas and the accumulated area under the chromatogram. This can be done by means of a computer or electronic integrator. The computer or integrator must have the capability of correcting for baseline shifts during the run.

7. Reagents and Materials 7. I Purity of Reagents--Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society where such specifications are available? Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination. 7.2 Air--Zero grade (hydrocarbon-free) is used as the FID oxidant. (Warning--Air is usually supplied as a compressed gas under high pressure and supports combustion.) 7.3 Carbon Dioxide (C0 2)DSupercritical fluid chromatographic grade, 99.99 % minimum purity, supplied pressurized in a cylinder equipped with a dip tube for removal of liquid CO 2. (WarningDLiquid at high pressure. Release of pressure results in production of extremely cold solid CO2 and gas which can dilute available atmospheric oxygen.) 7.4 Hydrogen--Hydrogen of high quality (hydrocarbonfree) is used as the fuel for the flame ionization detector. (Warning--Hydrogen is usually supplied under high pressure and is extremely flammable.) 7.5 Performance Mixture~A quantitative mixture of approximately 75 mass % hexadecane (n-C~6), 20 mass % toluene, 3 mass % tetralin (1,2,3,4-tetrahydronaphthalene), and 2 mass % naphthalene is used for performance checks. 7.6 Reference Fuel--A fuel (motor diesel fuel, aviation turbine fuel, or blend stock) with accepted values for both mass % total aromatics and mass % polynuclear aromatic hydrocarbons which have been established through cooperative testing in multiple laboratories. 8. Preparation of Apparatus 8.1 Install the SFC instrumentation in accordance with the manufacturer's instructions. System operating conditions will depend upon the column used and optimization of performance. Conditions listed in Table 2 have been used successfully. If the performance characteristics in terms of retention and resolution, specified in 8.2, are not achieved, modify the temperature, pressure, or mobile phase flow rate to achieve compliance. A column of low activity may be reactivated by solvent rinsing using established liquid chro5 Reagent Chemicals, American Chemical Society Specifications, American Chemical Society, Washington, DC. For suggestions on the testing of rcagents not fisted by the American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.IC, and the United States Pharmacopeia and National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville, MD.

3 Data obtained in a comparison study of Test Methods D 1319 and D 5186 are filed at ASTM Headquarters with Research Report RR: D02-1276. 4 Results are filed at ASTM Headquarters. Request Research Report: 1:)021388.

807

I1~ TABLE 2 Parameter Column Vendor Packing Length (ram) ID (ram) Particle size, mm Temperature, *C CO2 pressure, atm Flow rate, ml./minz Injection, p.L FID, temperature, oC Air, mL/mln Ha, mL/mln Air makeup, mr./rain Analysis time, mln

A Chromegasphere SI 60 250 2 5 30 115 40 0.1 350 300 50 15 15-20

D 5186

Typical Operating Conditions B Suprex Patro-Pak S" 250 2 5 40 125 37 0.1 385 800 80 n/a 15

C YMC SI 60 500 1 10 30 115 33 0.06 350 280 33 n/a 24

O Howlett-Packerd HP-Hydrocarbon 250 4.6 5 28 107~ 20 0.5 350 400 50 n/a 5

Post-column (downstream) pressure regulation. a Decompressed, gaseous CO2 flow, measured at column exit.

matography activation techniques.

M;

NOTE l--This temperature can be increased (up to 40"C) if the resolution between the monoaromatics and polynuclear aromatics is not satisfactory. Lower temperatures are suggested to improve resolution between nonaromatics and monoaromatics.

RFi = response factor of Component i, RFc~6ffi response factor of hexadecane in performance mix, and R R F i = relative response factor of Component i. These values can then be compared to the theoretical response factor for each component in the performance mix as calculated by the following equation:

8.2 System Performance." 8.2.1 Resolution--Analyze the performance mixture prepared in 7.5. The resolution between the nonaromatics and monoaromatics (R~vM) must be at least four and resolution between the monoaromatics and polynuclear aromatics (R~o) must be at least two when calculated according to the following equations: 2 x (t2 - tl) Rnu = (1) 1.699 x (.v2 + Ym) R~D =

2

×

(t 4 -

q)

1.699 × (Y4 + Y3)

:120 × n) × / :26.4

~F,,,o = ( ~ f f

RF~ RFcl6

(5)

n

= number of carbon atoms in component molecule,

M W = molecular mass of component,

(2)

(3)

M, RRF;=

(12.~T'~~6/

where: 12.01 = atomic mass of carbon,

where: t~ = time for the n-el6 peak apex, s, t2 = time for the toluene peak apex, s, t3 = time for the tetralin peak apex, s, t4 = time for the naphthalene peak apex, s, y~ -- peak width at half height of n-C~6 peak, s, Y2 = peak width at half height of toluene, s, Y3 = peak width at half height of tetralin, s, and Y4 = peak width at half height of naphthalene, s. 8.2.2 Retention Time Reproducibility--Repeated injections of the performance mixture must show a retention time repeatability (maximum difference between duplicate runs) of not more than 0.5 % for n-C~6 and toluene peaks. 8.2.3 Detector Accuracy Test--This test method assumes that the FID response approximates the theoretical unit carbon response. To verify this assumption, analyze the performance mixture and calculate the response factors, relative to hexadecane, (RRF;) for each of the components in the performance mix, using the following equations: RF~-- A-L"

-- Component i in performance mix, known mass %,

(4)

226.4 = molecular mass of hexadecane, and 16 -- number of carbon atoms in hexadecane molecule. The measured R R F for each component in the test mixture must be within +10 % of the theoretical value as calculated with Eq 5 or summarized in Table 1. If this is not attained, it will be necessary to vary the injection volume, restrictor position, or detector gas flows, or combination thereof, until agreement is attained. 8.2.4 Detector Linearity Check: 8.2.4.1 The following procedure has been found to be useful for verifying detector linearity. However, the size of the n-C~6 diluent peak tends to exceed the linear range of the FID. Should this occur, the detector accuracy test (8.2.3) provides one indication of linear performance. 8.2.4.2 Accurately prepare weighed blends consisting of approximately 50 mass % and 25 mass % of a motor diesel fuel in n-Ci6. 8.2.4.3 Analyze the diesel fuel and two blends by the procedure in Section 9. 8.2.4.4 Calculate the amount of aromatics present in each sample as described in Section 10. Using the results obtained for the 50 mass % and 25 mass % dilutions, calculate the expected concentration of aromatics in the original diesel fuel using the following equation: (C + D) ,4 = B × ~ (6) where: ,4 --- aromatics in the original fuel, mass %, B = aromatics in the diluted fuel, mass %,

where: Ai = Component i in performance mix, area %, 808

~) D 5186 C = mass of hexadecane in the dilution, and D = mass of original diesel fuel in the dilution. 8.2.4.5 Compare the results obtained for mass % aromatics in the original diesel fuel and the two dilutions. These values should agree to within the repeatability limits stated in 13.1.1. If agreement is not obtained, it may be necessary to adjust the restrictor position, FID gas flows, clean the FID, or decrease the injection volume.

AM A N + A M + AP

(7)

P % : 100 x

AP AN + A M + AP

(8)

where: M % ffi monoaromatics in sample, mass %, P % --- polynuclear aromatic hydrocarbons in sample, mass %, A % = total aromatics in sample, mass %, A M = area of monoaromatics in sample, A N ffi area of nonaromatics in sample, and AP ffi area of polynuclear aromatic hydrocarbons in sample. 11. Quality Control 11.1 Prior to the analysis of any samples in a given 24-h period, the laboratory must analyze at least one sample of reference fuel using the procedures defined in Section 9. All samples to be analyzed using this test method must fall within 5 mass % total aromatics and 1.5 mass % polynuclear aromatics ofat least one of the reference fuels chosen for this quality control check. Results from the analysis of a reference diesel fuel sample must agree with the accepted value for total aromatics to within +2.0 mass % and with the accepted value for polynuclear aromatics to within :t:l.0 mass %. If this agreement with the accepted values for a reference fuel sample is not attained, corrective action, verified by successful analysis of the reference fuel sample, must be taken prior to the analysis of any samples. 12. Report 12.1 Report the mass % of monoaromatics, polynuclear aromatic hydrocarbons, and total aromatics to the nearest one tenth of a percent (0.1%).

10. Calculation 10.1 Determine the mass % for monoaromatics, polynuclear aromatic hydrocarbons, and total aromatics content as follows:

13. Precision and Bias 13.1 The precision of the procedure in this test method as determined by the statistical examination of interlaboratory test results is as follows.4 13.1.1 Repeatability---The difference between successive results obtained by the same operator with the same apparatus under constant operating conditions on identical test material would, in the long run, in the normal and correct operation of the test method exceed the following values only in one case in twenty (see Tables 3 and 4).

[ Aromatics

\

TABLE 3

9I

I

I

10

11

EndNon-Aromatics/Begin Aromatics StartIntegration FIG. 1

Typical

I --

1

12

13

(9)

A%ffiM%+P%

9. Procedure 9.1 Using the same conditions as determined and used in Section 8, analyze the samples. Record the chromatographic data, stopping only when the sample has been completely eluted from the column. This is observed, at the end of the run, by the detector signal returning to baseline and remaining there. This will generally occur after the elution of the tricyclic aromatics. 9.2 Integrate the total chromatographic area from the beginning of the first peak to the return to baseline at the end of the chromatogram (see Fig. 1). 9.2.1 The chromatogram consists of one peak for the nonaromatics and one or more peaks for the aromatics. 9.2.1.1 Assign the area corresponding to the first peak (terminating at the bottom of the lowest valley between the retention times of hexadecane and toluene from the analysis of the performance mix) to the nonaromatics. 9.2.1.2 All of the integrated area eluting after the bottom of this valley but prior to the time corresponding to the start (not the apex) of the napthalene peak (determined in the analysis of the performance mixture) is assigned to the monoaromatics. Use area summing to determine the total area of this region in the chromatogram. 9.2.1.3 All of the integrated area occurring after the start time of the naphthalene peak through the final return to baseline is assigned to the polynuclear aromatic hydrocarbons. Use area summing to determine the total area of this region in the chromatogram.

l~omatics

M % : 100 x

1

14

EndIntegratton-

Chromatogram

809

Precision E s t i m a t e E T o t a l

Total Aromatics, mass ~

Repeatability, mass ~

1 5 10 15 20 25 35 50 75

0.2 0.2 0.3 0.3 0.3 0.3 0.4 0.4 0.4

Aromatics Reproducibility, mass 0.8 1.1 1.3 1.4 1.5 1.6 1.7 1.8 2.0

~ D5186 TABLE 4

0.5 1 2 3 5 10 15 25 50

single and independent results obtained by different operatore working in different laboratories on identical test material would, in the long run, exceed the following values only in one case in twenty (see Tables 3 and 4). Reproducibility ffi 0.75 (X) °-23 mass % for total aromatics, ffi 0.47 (X)°'45 mass % for polynuclear aromatics where Xis less than 5 mass %, ffi 1.77 (X) °'~° mass % for polynuclear aromatics where X is greater than 10 mass %. 13.2 B/as--Reference materials for this test method are being developed which can be used as a measure of the test method's bias.

Precision Estimate--Polynuclear Aromatics

Polynuclear Aromatics, mass "~

Repeatability, mass'& 0.1 0.2 0.2 0.2 0.2 0.5 0.5 0.5 0.6

Reproducibility, rrmss ~ 0.3 0.5 0.6 0.8 1.0 5.6 6.9 8.9 12.5

Repeatability = 0.16 (X) 0"23 mass % for total aromatics, ffi 0.16 (X) T M mass % for polynuclear aromatics where X is less than 5 mass %, = 0.36 (X) °'13 mass % for polynuclear aromatics where X is greater than 10 mass %. 13.1.2 Reproducibility---The difference between two

14. Keywords 14.1 aromatics; aromatic hydrocarbons; diesel fuel; monoaromatics; polynuclear; supercritical fluid chromatography

The American Society for Testing and Materials takes no position respecting tim validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of Infringement of such rights, are entirely their own responsibility. This standard is subject to revision st any time by the responsible technical committee and must be reviewed every five years and ff not revised, either reepproved or withdrawn. YoUr comments are Invited either for revision of this standard or for additional standards and should be addressed to ASTM Heeclquarters. Your comments will receive careful consideration at a meeting of the responsible technical ¢~rnmlttee, which you may attend, ff you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 100 Barr Harbor Drive, West Conshohocksa, PA 19428.

810

(1~)

Designation: D 5190 - 96 Standard Test Method for Vapor Pressure of Petroleum Products (Automatic Method) 1 This standard is issued under the fixed designation D 5190; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last re.approval. A superscript epsilon (0 indicates an editorial change since the last revision or re.approval.

3.1.2 dry vapor pressure equivalent (DVPE), n--a value calculated by a correlation equation (see 13.1) from the total pressure. 3.1.2. I Discussion--The DVPE is expected to be equivalent to the value obtained on the sample by Test Method D 4953, Procedure A.

1. Scope 1.1 This test method covers the determination of the total pressure of air-containing, volatile, petroleum products. This test method is suitable for testing samples with boiling points above 0°C (32"1) that exert a vapor pressure between 7 and 172 kPa (1 and 25 psi) at 37.8"C (100"1) at a vapor-to-liquid ratio of 4:1. This test method is suitable for testing gasoline samples that contain oxygenates. No account is made of ~AI~UA .~:.. ^1.v..Gut ., water in the sample. 1.2 This test method is suitable for the calculation of a dry vapor pressure equivalent (DVPE) by means of a correlation equation (see 13.1). The calculated DVPE very closely approximates the dry vapor pressure that would be obtained on the same material when tested in accordance with Test Method D 4953. 1.3 The values stated in SI units are to be regarded as the standard. The inch-pound units given in parentheses are provided for information only. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements, see Notes 2 and 4.

4. Summary of Test Method ................ v,,, cup of the automatic vapor pressure instrument is Idled with chilled sample and is coupled to the instrument inlet fitting. The sample is then automatically forced from the sample chamber to the expansion chamber where it is held until thermal equilibrium at 37.8"C (100"1) is reached. In this process the sample is expanded to five times its volume (4:1 vapor-to-liquid ratio). The vapor pressure is measured by a pressure transducer. 4.2 The measured vapor pressure is automatically converted to a dry vapor pressure equivalent value by the instrument. A correction to this value is necessary to account for the observed bias between the test result and that obtained by Test Method D 4953. 5. Significance and Use 5.1 Vapor pressure is an important physical property of volatile liquids. 5.2 The vapor pressure of gasoline and gasoline-oxygenate blends is regulated by various government agencies. 5.3 Specifications for volatile petroleum products generally include vapor pressure limits to ensure products of suitable volatility performance. 5.4 This test method is more precise than Test Method D 4953.

2. Referenced Documents 2.1 A S T M Standards: D 4057 Practice for Manual Sampling of Petroleum and Petroleum Products2 D 4953 Test Method for Vapor Pressure of Gasoline and Gasoline-Oxygenate Blends (Dry Method)3 D 5191 Test Method for Vapor Pressure of Petroleum Products (Mini Method)3 2.2 A S T M Adjunct: Detailed Drawings for Automatic Vapor Pressure Instrument4

6. Apparatus 6.1 Automatic Vapor Pressure Instrument, 5 the essential features describing the sample flow and operation of the automatic vapor pressure instrument is provided in Annex A I. Critical elements of the apparatus are included as follows: 6.1.1 Pressure Transducer, capable of operating in the range from 0 to 172 kPa (0 to 25 psi) with the resolution of O.l kPa (O.Ol psi) and a minimum accuracy of 3:0.7 kPa (3:0. I0 psi). 6.1.2 Thermostatically Controlled Heater, capable of maintaining an oil bath surrounding the test chambers at 37.8 3: 0.1*C (100 3: 0.2"1) for the duration of the test.

3. Terminology 3.1 Definitions of Terms Specific to This Standard." 3.1.1 totalpressure, n--the observed pressure measured in the experiment, that is the sum of the partial pressure of the sample and the partial pressure of the dissolved air. i This test method is under the jurisdiction of ASTM Committee 13-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee I)02.08 on Volatility. Current edition approved June 10, 1996. Published August 1996. Originally published as D 5190 - 91. Last previous edition D 5190 - 93a. 2 Annual Book of ASTM Standards, Vol 05.02. 3Annual Book of ASTM Standards, Vol 05.03. (Available from ASTM Headquarters. Order PCN 12.500140-12.

s The following instrument has been found suitable by interlaboratory cooper. ative testing: Vapor Pressure lmtrument, avmlable from Southwest Research Institute, San Antonio, Texas.

811

@ D 5190 8.2 Sampling Handling Temperature--Cool the sample container and contents in an ice bath or refrigerator to 0 to I°C (32 to 34°F) prior to opening the sample container. Allow sufficient time to reach this temperature. Verify the sample temperature by direct measurement of the temperature of a similar liquid in a similar container placed in the cooling bath or refrigerator at the same time as the sample. 8.3 Verification of Sample Container Filling--With the sample at a temperature of 0 to 1°C, take the container from the cooling bath, wipe dry with absorbent material and unseal. Using a suitable gage, confirm that the sample volume equals 70 to 80 % of the container capacity. 8.3.1 Discard the sample if the container is filled to less than 70 volume % of the container capacity. 8.3.2 If the container is more than 80 volume % full, pour out enough sample to bring the container contents within 70 to 80 volume % range. Do not return any sample to the container once it has been withdrawn. 8.4 Air Saturation of Sample in Sample Container: 8.4.1 With the sample again at a temperature of 0 to 1°C, take the container from the cooling bath or refrigerator, wipe it dry with an absorbent material, open it momentarily, taking care that no water enters, reseal, and shake it vigorously. Return it to the bath or refrigerator for a minimum of 2 rain. 8.4.2 Repeat 8.4.1 twice more. Return the sample to the bath or refrigerator until the beginning of the procedure. 8.5 Verification of Single Phase Samples--After drawing a test specimen into the sample cup and coupling the cup to the instrument for analysis, check the remaining sample for phase separation. If the sample is contained in a glass container, this observation can be made prior to sample transfer. If the sample is contained in a non-transparent container, mix the sample thoroughly and immediately pour a portion of the remaining sample into a glass container and observe for evidence of phase separation. If the sample is not clear and bright or if a second phase is observed, discard the test and sample.

6.1.3 Sample Cup, capable of holding up to 125 mL. 6.2 Iced.Water Bath or Air Bath, for chilling the test samples and sample cup to temperatures between 0 to I*C (32 to 34*F). 7. Reagents and Materials

7.1 Purity of ReagentsmChemicals of at least 98 % purity shall be used in the calibration procedure (see Section 10). Unless otherwise indicated, it is intended that all reagents conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society where such specifications are available. 6 Lower purities may be used, provided it is first ascertained that the reagent is of sufficient purity to permit its use without lessening the accuracy of the determination. NOTE l--Although' higher purity chemicals in the 99 + % range are preferred for use in calibrations,the precision and bias statements (see Section 15) were derived with the minimum purity levelstatedin 7.1.

7.2 7.3 7.4 7.5

2,2-Dimethylbutane. n-Hexane, (Warningmsee Note 2). n-Pentane, (Warningmsee Note 2). Toluene, (Warning~see Note 2).

NOTE 2: Warnlng--2,2-Dimethylbutane, n-hexane, n-pentane, and toluene are extremely flammable, harmful if inhaled. Skin irritant on repeated contact. Aspiration hazard.

8. Sampling

8.1 GeneralProcedures: 8.1.1 The extreme sensitivity of vapor pressure measurements to losses through evaporation and the resulting change in composition is such as to require the utmost precaution and the most meticulous care in the drawing and handling of samples. 8.1.2 Obtain a sample and test specimen in accordance with Practice D 4057, except do not use, "Sampling by Water Displacement," for fuels containing oxygenates. Use a I-L (l-qt) sized container filled between 70 and 80 % with the sample.

9. Preparation of Apparatus

NOTE 3--The present precision statement was derived using the samples in I-L (l-qt) containers. However, the samples in containers of

other sizes,as prescribed in Practice D 4057 can be used, withthe same ullage requirement,if it is recognizedthat the precisioncan be affected. 8.1.3 In the case of referee testing, the I-L (l-qt) sample container is mandatory. 8.1.4 Perform the vapor pressure determination on the first test specimen withdrawn from a sample container. Do not use the remaining sample in the container for a second vapor pressure determination. If a second determination is necessary, obtain a new sample. 8.1.5 Protect the samples from excessive temperatures prior to testing. This can be accomplished by storage in an appropriate ice bath or refrigerator. 8.1.6 Do not test samples stored in leaky containers. If leaks are detected, discard and obtain a new sample.

9.1 Prepare the automatic vapor pressure instrument for operation in accordance with the manufacturer's instructions. 9.2 Clean and dry the sample cup prior to use. NOTE 4: Caution--Do not analyzea water saturated sample. If water is accidentallyintroducedinto the instrument,analyzea dry sample six to ten timesuntil all the waterhas been flushedfrom the instrumentand a repeatabilityof :el.4 kPa (0.20 psi) is obtained for dupficate runs. 9.3 Chill the stoppered, dry sample cup to between 0 and I°C (32 and 34°F) in a refrigerator or ice bath before transferring the sample into the cup. Avoid water contamination of the sample cup by sealing the sample cup during the cooling process. 9.4 Prior to starting the measurement, check that the temperature of the test chamber is within the required range specified by the manufacturer of the instrument. 10. Calibration 10.1 Pressure Transducer: 10.1.1 Calibrate the pressure transducer at least every 30 days or when needed as indicated from the performance checks. The calibration of the transducer is accomplished

Reagent Chemicals, American Chemical Society SpecO~cations, American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed by the American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville, MD.

812

@ D 5190 ChilledSample

using three reference materials to cover the range above and below 34 kPa (5.0 psi).

~ q u i d

Chamber

NOTE 5--The instrument manufacturer provides an alternative calibration procedure using two reference points, zero pressure (<0.1 kPa) and the ambient barometric pressure. However, since this procedure was not included in the interlaboratory program, the precision and bias can be affected by its use. 10.1.2 Load n-hexane into the instrument, obtain a vapor pressure reading and then adjust the zero potentiometer for the transducer to obtain a calibration value of 5.00 _+ -0.02 on the digital meter display.

(ol Sample Container Prior to Transfer of Sample

NOTE 6--The target calibration values used in this section are specific to the automatic vapor pressure instrument5 evaluated in the 1988 interlaboratory cooperative program.7 These calibration values do not necessarilycorrespond to the total vapor pressures or the dry vapor pressures (Test Method D 4953) reported for the reference calibration materials, but rather are values that the instrument manufacturer suggests using to produce a dry vapor pressure equivalent reading on the digital display.

(b) (c) Sealing Closer Gasoline Chamber Replacedby Sample Placed Over Liquid Translet Connect=on Oel=veryTube

~ " (d) Posfllon of System for Sample Transler

FIG. 1 Simplified Sketches Outlining Method Tran=ferdng Sample to Liquid Chamber from Oben-TypeContainers

2-methylpentane 46.7 kPa (6.77 psi); cyclohexane 22.5 kPa (3.26 psi); and toluene 7.1 k / a (1.03 psi). 9 NOTE 7--It is recommended that at least one type of control sample used in 11.I be representative of the fuel(s) regularly tested by the laboratory. The total vapor pressure measurement process (including operator technique) can be checked periodically by performing this test method on previously prepared samples from one batch of product, as per procedure described in 8.1.2. Samples should be stored in an environment suitable for long term storage without sample degradation. Analysis of result(s) from these quality control samples can be carded out using control chart techniques=° or other statistically equivalent techniques.

10.1.3 Load n-pentane into the instrument, obtain a pressure reading on the digital meter, and then adjust the transducer span potentiometer to achieve a value o f 15.40 + -0.05 on the digital meter. 10.1.4 Repeat 10.1.2 and 10.1.3 until the appropriate calibration values are displayed without making further adjustments. 10.1.5 Load the instrument with 2,2-dimethylbutane and obtain a pressure reading. If the digital display reads 9.90 + 0.1 then the instrument is calibrated; if not, then repeat the above procedure until a satisfactory calibration is achieved. 10.1.6 For calibration of the range below 34 kPa (5.0 psi) perform the steps in 10.1.2 to 10.1.4 replacing n-hexane (34 k/a) in step 10.1.2 with toluene (7 k/a), and replacing n-pentane (106 kPa) in step 10.1.3 with n-hexane (34 k/a). 10.2 Temperature~Atleast every six months, check the calibration of the thermometer used in the thermostatically controlled bath against a National Institute of Standards and Technology (NIST) traceable thermometer and check the capability of the bath thermostat control to maintain a temperature of 37.8 + 0.1"C (100 + 0.2°F) throughout the measurement period. Take corrective actions when the thermometer and thermostat exceed the limits stated.

12. Procedure 12.1 Sample Transfer--Remove the sample from the cooling bath or refrigerator, dry the exterior of the container with absorbent material, uncap, and insert a chilled transfer tube apparatus (see Fig. 1). Quickly take the chilled sample cup and place it, in an inverted position, over the sample delivery tube o f the transfer apparatus. Invert the entire system rapidly so that the sample cup is uptight with the end of the delivery tube touching the bottom of the sample cup. Fill the sample cup to overflowing. Withdraw the delivery tube from the sample cup while allowing the sample to continue flowing up to the moment of complete withdrawal. NOTE 8: Precaution--In addition to other precautions make provisions for suitable restraint (for example, catch pan) and disposal of the overflowingor spilled gasoline to avoid fire hazard.

11. Quality Control Checks 11.1 Confirm the calibration of the instrument each day it is in use by running a control sample of known volatility. These materials should be treated in an identical manner as a sample (see Sections 8 and 12). Record the dry vapor pressure equivalent and compare this to the statistical value of the control sample from your laboratory. If the difference exceeds your control limits, check the calibration of the instrument. 11.2 Some possible materials and their corresponding vapor pressures, as found in ASTM DS4B, s include: cyclopentane, 68.3 k / a (9.91 psi); 2,2-dimethylbutane 68.0 kPa (9.86 psi); 2,3-dimethylbutane 51.1 kPa (7.41 psi);

12.2 Quickly couple the sample cup to the instrument and start the analysis in accordance with the manufacturer's instructions for operation of the instrument. The total time between opening the chilled sample container and securing the sample cup to the instrument shall not exceed 1 rain. 12.3 At the completion of the test, record the uncorrected dry vapor pressure reading from the digital meter to the nearest 0.1 kPa (0.01 psi). If the instrument does not automatically calculate the DVPE, record the uncorrected vapor pressure reading and calculate the DVPE using Eq 1 (see 13.1). 9 The vapor pressure values cited were obtained from Phillips Petroleum Company, Bartk~ville, Oklahoma, or ASTM DS 4B Physical Constauts of Hydrocarbon and Non-Hydrocarbon Compounda. to Reference ASTM MNL 7, Manual on Presentation of Data and Control Chart Analysis, Sixth Edition, Section 3: Control Charts for Individuals.

Supporting data are available from ASTM Headquarters. Request RR:D021260. = =Physical Constants of Hydrocarbon and Non-Hydrocarbon Materials," available from ASTM Headquarters. Order PCN 284)03092-12.

813

~

D 5190 Test Method D 5191. In addilion, six sets were tested by modified D 5190 and 13 by modified Test Method D 5191. H

13. Calculation 13.1 Calculate a dry vapor pressure equivalent (DVPE) using the following equation. This corrects the instrument reading for the relative bias found in the 1991 interlaboratory cooperative test program (see Note 9) between the dry vapor pressure measured in accordance with Test Method D 4953, procedure A and this test method: DVPE -- (0.954 X) + A (1) where: X ffi measured total vapor pressure, in units consistent with A, and A ffi 1.94 kPa (0.281 psi).

15.1.1 Repeatability---Tbe difference between successive test results obtained by the same operator with the same apparatus under constant operating conditions on identical test material would, in the long run, in the normal and correct operation of the test method exceed the following value only in one case in twenty: 2.48 kPa (0.36 psi) 15.1.2 Reproducibility-The difference between two single and independent test results obtained by different operators working in different laboratories on identical test material would, in the long run, exceed the following value only in one case in twenty: 3.45 kPa (0.50 psi) 15.2 Bias: 15.2.1 Since there is no accepted reference material suitable for determining the bias for the procedures in this test method, bias cannot be determined. 15.2.2 A statistically significant relative bias was observed in the 1991 interlaboratory cooperative test program described in Note 9 between the total pressure obtained using this test method and the dry vapor pressure obtained from using Test Method D 4953, Procedure A. This bias can be corrected by applying Eq. (1) as described in Section 13.

14. Report 14.1 Report the corrected dry vapor pressure equivalent pressure to the nearest 0.1 kPa (0.01 psi) without reference to temperature.

15. Precision and Bias 15.1 Precision--The precision of this test method as determined by the statistical examination of the interlaboratory test results is as follows: NOTS 9--The following precision data were developed in a 1991 interlabomtory cooperativetest prosram. Participants analyzed sample sets comprised of blind duplicates of 14 types of hydrocarbons and hydroearbon-oxygenateblends. The oxygenatecontent (MTBE,ethanol, and methanol) ranged from 0 to 15 % by volumenominal and the vapor pressure ranged from 14 to 100 kPa (2 to 15 psi) nominal. A total of 60 laboratories participated. Some participants performed more than one test method, using separatesample sets for each. Twenty-sixsamplessets were tested by Test Method D 4953, 13 by this test method, and 27 by

16. Keywords 16.1 automated vapor pressure measurement; dry vapor pressure; gasoline; hydrocarbon-oxygenate blends; petroleum products; vapor pressure i, The results of this test program are filed at ASTM Headquarters. Request RR:D02-1286.

ANNEX (Mandatory Information) A1. ESSENTIAL COMPONENTS AND FUNCTION OF AN AUTOMATIC VAPOR PRESSURE INSTRUMENT AI.2.3 Drain valve (6) opens for I s to permit 5 to 15 mL of sample to flow to the drain. AI.2.4 Pneumatic valve (1) is normally open in the C-A position, maintaining pressure on the top of the air cylinder (15) to keep the piston assembly (22) in the down stroke position. In this position, pneumatic valve (2) is normally closed in the B-A position. AI.2.5 Pneumatic valves (1), (2), (3) and (4) are electrically tied together. When power is applied to these valves, pneumatic valve (1) closes to C-A position, valve (2) opens to B-A position, sample valve (3) and flush valve (4) open simultaneously. Pneumatic pressure applied to cylinder piston (15) through valve (2), with relief through valve (1), forces the piston up (this is the fill stroke). As the piston moves up, 10 to 15 mL of sample is drawn into sample cylinder (24), and the residue from the previous sample is

A I.I The essential components of an automatic vapor pressure instrument are indicated in Fig. A 1.1. The instrument consists of a system of valves, tubes, and expansion chambers that automatically loads a sample into a pressure chamber and then expands the chamber volume by five times. A pressure transducer measures the resulting vapor pressure of the sample. AI.2 OperationsSequencefor Loading Sample: A 1.2.1 Depression of the start switch provides the impulse to start the analysis cycle. A timing board circuit operates to produce the required analysis program. Refer to Fig. A 1.1 for the identification of the various part numbers (indicated in parentheses) that are essential to the operation. AI.2.2 After initiation, air valve (5) opens to apply 96.5 kPa (13.8 psi) to the sample cup (27).

814

~)

D 5190

FLOWSYSTEM

"O'R BOTH

® DRAIN PRESSURE-VAC FOR CALI8R&TION

DRAIN

~ FIG. A1.1

"

~

21

"Ci RINGINSAMPLEINLET CONNECTOR

FlowSystemfor AutomaticVaporPressure Instrument

evacuated from the expansion chamber (26) through flush valve (4). This fill stroke requires about 10 s. AI.2.6 Power is removed from pneumatic valve (2) that closes position B-A. Pneumatic valve (1) is open to C-A. Sample valve (3) and flush valve (4) and close and transfer valve (7) opens. Pneumatic pressure applied through valve (1), with relief through valve (2), forces the piston down. Liquid is forced from the sample chamber through transfer valve (7) into the expansion chamber. Stroke time is about 10s. A1.2.7 Steps A1.2.5 and A1.2.6 are repeated three times for a total of four sampling, each taking 10 to 15 mL of the sample. The first three samplings are used to flush the system clean. The fourth sample is held in the expansion chamber to thermal equilibrium. AI.2.8 At the end of the fourth expansion stroke, transfer valve (7) closes. The piston is retained in the down position by pneumatic pressure through valve (1). Sample cup drain valve (6) opens, and the sample remaining in the cup (27) is forced to drain. A1.2.9 Conditions remain static for about 3.5 min to permit the expanded sample in the chamber to attain thermal equilibrium. A1.3 Measurement Cycle: A I.3.1 Approximately 45 s before the end of the cycle, the digital display meter for the transducer is freed, permitting it to display the vapor pressure of the sample as received from the pressure transducer (28). Air valve (5) and sample cup drain valve (6) close before the display meter locks for the next run. AI.3.2 At the end of the analysis cycle, the dry vapor pressure equivalent is automatically calculated and displayed.

The American Society for Testing en(YMaterials takes ,"topoaltlon re#pectlng the validity of any patent rights a.c,ierted in eonr41ctlon with any item mentioned In thl# standud. ~ of t,~i8 Mandard are e x p r e u / y edv/eed that de,ofm/nat/on oq the val/d/f)" of any such patent rights, and the risk of kdringement of such rights, are enffrely their own mepor~llbllity. This 8tendard is subject to revision at any time by the retJpon#tDletechnical comrn~ee and must be reviewed every five years =l?d ff not revised, either reepproved or w#.hdrewn. Your ~mmern are invited either for reel#Ionof this standard of for additional standards and should be eddre~md to ASTM H e ~ e n l . Your ~ will recefve careful cotwlderatlon ef a n~etlng oi the rcRponslble technical committee, which you may attend, ff you fee/that your comme¢~ heve not received a fair hearlr~ you should make your views known to the ASTM Committee on 8tandaro~, 100 Barr HarDor Drive, WeM Con$hohocken, PA 19428.

815

,) Designation: D 5191 - 96

Standard Test Method for Vapor Pressure of Petroleum Products (Mini Method) 1 This standard is issued under the fixed designation D 5191; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (E) indicates an editorial change since the last revision or reapproval.

3.1.2 dry vapor pressure equivalent (DVPE)--a value calculated by a correlation equation (see 13.2) from the total pressure. 3.1.2.1 Discussion--The DVPE is expected to be equivalent to the value obtained on the sample by Test Method D 4953, Procedure A. 3.1.3 total pressure--the observed pressure measured in the experiment that is the sum of the partial pressure of the sample and the partial pressure of the dissolved air.

1. Scope 1.1 This test method covers the use of automated vapor pressure instruments to determine the total vapor pressure exerted in vacuum by air-containing, volatile, liquid petroleum products. This test method is suitable for testing samples with boiling points above 0°C (32°F) that exert a vapor pressure between 7 and 130 kPa (1.0 and 18.6 psi) at 37.8°C (100°F) at a vapor-to-liquid ratio of 4:1. Measurements are made on liquid sample sizes in the range of I to 10 mL. No account is made for dissolved water in the sample. NOTE I - - S a m p l e s c a n also be tested at o t h e r vapor-to-fiquid ratios,

temperatures, and pressure~ but the precision and bias statementsneed not apply. 1.2 This test method is suitable for calculation of the dry vapor pressure equivalent (DVPE) of gasoline and gasolineoxygenate blends by means of a correlation equation (see 13.2). The calculated DVPE very closely approximates the dry vapor pressure that would be obtained on the same material when tested by Test Method D 4953. 1.3 The values stated in SI units are regarded as standard. The inch-pound units given in parentheses are provided for information only. 1.4 This standard does not purport to address all of the safety concerns, Or any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific warning statements, see Note 5. 2. Referenced Documents

2. I A S T M Standards: D 2892 Test Method for Distillation of Crude Petroleum (15-Theoretical Plate Column)2 D4057 Practice for Manual Sampling of Petroleum and Petroleum Products2 D 4953 Test Method for Vapor Pressure of Gasoline and Gasoline-Oxygenate Blends (Dry Method)3

4. Summary of Test Method 4.1 A known volume of chilled, air-saturated sample is introduced into an evacuated, thermostatically controlled test chamber, the internal volume of which is five times that of the total test specimen introduced into the chamber. Af~er injection into the test chamber, the test specimen is allowed to reach thermal equilibrium at the test temperature, 37.8°C (100°F). The resulting rise in pressure in the chamber is measured using a pressure transducer sensor and indicator. Only total pressure measurements (sum of the partial pressure of the sample and the partial pressure of the dissolved air) are used in this test method, although some instruments can measure the absolute pressure of the sample as well. 4.2 The measured total vapor pressure is converted to a dry vapor pressure equivalent (DVPE) by use of a correlation equation (see 13.2). 5. Significance and Use 5.1 Vapor pressure is a very important physical property of volatile liquids. 5.2 The vapor pressure of gasoline and gasoline-oxygenate blends is regulated by various government agencies. 5.3 Specifications for volatile petroleum products generally include vapor pressure limits to ensure products of suitable volatility performance. 5.4 This test method is more precise than Test Method D 4953, uses a small sample size (l to 10 mL), and requires about 7 rain to complete the test. 6. Apparatus 6.1 Vapor Pressure Apparatus--The type of apparatus4 suitable for use in this test method employs a small volume test chamber incorporating a transducer for pressure measurements and associated equipment for thermostatically controlling the chamber temperature and for evacuating the test chamber prior to sample introduction.

3. Terminology 3.1 Definition of Terms Specific to This Standard." 3.1.1 absolute pressure--the pressure of the air-free sample. It is calculated from the total pressure of the sample by subtracting out the partial pressure of the dissolved air. t This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.08 on Volatility. Current edition approved June 10, 1996. Published August 1996. Originally published as D 5191 - 91. Last previous edition D 5191 - 93a. a Annual Book o f A S T M Standards, Vol 05.02. 3 Annual Book of A S T M Standards, Vol 05.03.

4 The following instruments have been found satla/hctory for use in this test method as determined by interlaboratory cooperative testin[ CCA-VP, CCA-VPS, available from Grabner Instruments, Vienna, Austria, and Petxolab, LathAm~NY, 12110, and Setavap, available from Stanhope-Seta, Chert~y, England and Core Labs Refinery Systems, Princeton, NJ 08540-6299.

816

~1~) D 5191 6.1.1 The test chamber shall be designed to contain between 5 and 50 mL of liquid and vapor and be capable of maintaining a vapor-to-liquid ratio between 3.95 to 1.00 and 4.05 to 1.00. NoTE 2--The test chamber employed by the instruments used in generating the precision and bias statements were constructed of stainless steel or aluminum. NOTE 3reTest chambers exceeding a 15 mL capacity can be used, but the precision and bias statements (see Section 14) are not known to apply. 6.1.2 The pressure transducer shall have a minimum operational range from 0 to 177 kPa (0 to 25.7 psi) with a minimum resolution of 0.1 kPa (0.01 psi) and a minimum accuracy of 4-0.8 kPa (4-0.12 psi). The pressure measurement system shall include associated electronics and readout devices to display the resulting pressure reading. 6.1.3 A thermostatically controlled heater shall be used to maintain the test chamber at 37.8 4- 0.1*C (100 4- 0.2*F) for the duration of the test. 6.1.4 A platinum resistance thermometer shall be used for measuring the temperature of the test chamber. The minimum temperature range of the measuring device shall be from ambient to 75"C (167"F) with a resolution of 0.1*C (0.2*F) and an accuracy of 0. l*C (0.2*F). 6.1.5 The vapor pressure apparatus shall have provisions for introduction of the test specimen into an evacuated test chamber and for the cleaning or purging of the chamber following the test. 6.2 VacuumPump, capable of reducing the pressure in the test chamber to less than 0.01 kPa (0.001 psi) absolute. 6.3 Syringe, (optional, depending on sample introduction mechanism employed with each instrument) gas-tight, 1 to 20 mL capacity with a 4-1% or better accuracy and a 4-1% or better precision. The capacity of the syringe should not exceed two times the volume of the test specimen being dispensed. 6.4 Iced Water Bath or Air Bath, for chilling the samples and syringe to temperatures between 0 to l°C (32 to 34°F). 6.5 MercuryBarometer, 0 to 120 kPa (0 to 17.4 psi) range. 6.6 McLeod Vacuum Gage, to cover at least the range of 0 to 0.67 kPa (0 to 5 m m Hg). Calibration of the McLeod gage is checked in accordance with Annex A6 of Test Method D 2892.

7. Reagents and Materials 7.1 Purity of Reagents--Use chemicals of at least 99 % purity for quality control checks (see Section 10). Unless otherwise indicated, it is intended that all reagents conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society where such specifications are available. 5 Lower purities can be used, provided it is first ascertained that the reagent is of sufficient purity to permit its use without lessening the accuracy of the determination. 5 Reagent Chemicals, American Chemical Society Sp~'oqcations, American Chemical Society, Wa~ington, DC. For suggestions on the testing of reagents not by the American Chemical Society, s e e dnalar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and National Formulary, U.$. PMrmaceufical Convention, Inc. (USPC), RockviUe, MD.

NOTE 4raThe chemicals in this section are suggested for use in quality control procedures (see 11.2) and are not used for instrument calibration. 7.2 7.3 7.4 7.5 7.6 7.7

Cyclohexane(Warning--See Note 5.) Cyclopentane(Wm~alng--See Note 5.) 2,2-Dimethylbutane(Warning--See Note 5.) 2,3-Dimethylbutane(Warning--See Note 5.) 2-Methylpentane(Warning--See Note 5.) Toluene(Warning--See Note 5.)

NOTE 5: Wm-nlng--Cyclohexane, toluene, cyclopentane, 2,2dimethylbutane, 2,3-dimethylbutane and 3-methylpentane are flammable. Health Hazard.

8. Sampling

8.1 GeneralRequirements: 8.1.1 The extreme sensitivity of vapor pressure measurements to losses through evaporation and the resulting changes in composition is such as to require the utmost precaution and the most meticulous care in the drawing and handling of samples. 8.1.2 Obtain a sample and test specimen in accordance with Practice D 4057, except do not use the "Sampling by Water Displacement" section for fuels containing oxygenates. Use a 1 L (1 qt) sized container filled between 70 and 80 % with sample. NOTE 6--The present precision statement was derived using samples in 1 L (1 qt) containers. However,samples in containersof other sizesas prescribed in Practice D 4057 can be used, with the same ullage requirement, if it is ree.Ogni7~X!that the precision can be affected. 8.1.3 In the case of referee testing, the I L (1 qt) sample container is mandatory. 8.1.4 Perform the vapor pressure determination on the first test specimen withdrawn from a sample container. Do not use the remaining sample in the container for a second vapor pressure determination. If a second determination is necessary, obtain a new sample. 8.1.5 Protect samples from excessive temperatures prior to testing. This can be accomplished by storage in an appropriate ice bath or refrigerator. 8.1.6 Do not test samples stored in leaky containers. Discard and obtain a new sample if leaks are detected. 8.2 Sampling Handling Temperature--Cool the sample container and contents in an ice bath or refrigerator to the 0 to I*C (32 to 34"F) range prior to opening the sample container. Allow sufficient time to reach this temperature. Verify the sample temperature by direct measurement of the temperature of a similar liquid in a similar container placed in the cooling bath or refrigerator at the same time as the sample. 8.3 Verification of Sample Container Filling--With the sample at a temperature of 0 to I°C, take the container from the cooling bath, wipe dry with absorbent material and unseal. Using a suitable gage, confLrm that the sample volume equals 70 to 80 % of the container capacity. 8.3.1 Discard the sample if the container is filled to less than 70 %, by volume, of the container capacity. 8.3.2 If the container is more than 80 % by volume full, pour out enough sample to bring the container contents within the 70 to 80 % by volume range. Do not return any sample to the container once it has been withdrawn. 817

( ~ D 5191 8.3.3 Reseal the container and place it back in the cooling bath or refrigerator. 8.4 Air Saturation of Sample in Sample Container: 8.4.1 With the sample again at a temperature of 0 to I*C take the container from the cooling bath or refrigerator, wipe it dry with an absorbent material, open it momentarily, taking care that no water enters, reseal and shake it vigorously. Return it to the cooling bath or refrigerator for a minimum of 2 min. 8.4.2 Repeat 8.4.1 twice more. Return the sample to the cooling bath or refrigerator until the beginning of the procedure. 8.5 Verification of Single PhasemAfler drawing a test specimen and injecting it into the instrument for analysis, check the remaining sample for phase separation. If the sample is contained in a glass container, this observation can be made prior to sample transfer. If the sample is contained in a non-transparent container, mix the sample thoroughly and immediately pour a portion of the remaining sample into a glass container and observe for evidence of phase separation. If the sample is not clear and bright or i f a second phase is observed, discard the test and the sample.

total pressure and not a calculated or corrected value. Compare this pressure value with the pressure obtained from a Fortin-type mercurial barometer, as the pressure reference standard. The barometer must measure the local station pressure at the same elevation as the apparatus in the laboratory, at the time of pressure comparison. NOTE 8: Caution--Many aneroid barometers,such as thoseused at weatherstationsand airports,are pre-eorrectedto givesea levelreadings; thesemust not be used for calibrationof the apparatus. I0.I.3.1 The barometric pressure reading must be corrected for the change in the density of the mercury column between 0°C and the operating temperature and converted to the same units of pressure as the vapor pressure apparatus display. After making the density correction, the conversion for the height of a mercury column at 0*C to kPa or psia is made as follows: I in. (25 m m ) H g at 0*C ffi3.3865 kPa or = 0.49116 psia. I0.I.4 Repeat I0.I.2 and I0.I.3 until the zero and barometric pressures read correctly without further adjustments. I0.2 ThermornetermCheck the calibration of the platinum resistance thermometer used to monitor the temperature of the test chamber at least every six months against a National Institute of Standards and Technology (NIST) traceable thermometer.

9. Preparation of Apparatus 9.1 Prepare the instrument for operation in accordance with the manufacturer's instructions. 9.2 Clean and dry the test chamber as required to avoid contamination of the test specimen. Prior to sample introduction, visually determine from the instrument display that the test chamber pressure is stable and does not exceed 0.1 kPa (0.01 psi). When the pressure is not stable or exceeds this value, check that the chamber is clean of volatile materials remaining in the chamber from a previous sample or check the calibration of the transducer. 9.3 If a syringe is used for introduction of the sample specimen, chill it to between 0 and 4.5°C (32 and 40*F) in a refrigerator or ice bath before drawing in the sample. Avoid water contamination of the syringe reservoir by sealing the outlet of the syringe during the cooling process. 9.4 Prior to introduction of the test specimen, check that the temperature of the test chamber is within the required range of 37.8 + 0.1"C (I00 ± 0.2*F).

11. Quality Control Checks 11.1 Confirm the calibration of the instrument each day it is in use by running a control sample of known volatility. These materials should be treated in an identical manner as a sample (see Sections 8 and 12). Record the dry vapor pressure equivalent value and compare this to the statistical value of the control sample from your laboratory. If the difference exceeds your control limits, check the calibration of the instrument. 11.2 Some possible materials and their corresponding vapor pressures, as found in ASTM DS4B, 6 include: cyelopentane, 68.3 kPa (9.91 psi); 2,2-dimethylbutane 68.0 kPa (9.86 psi); 2,3-dimethylbutane 51.1 kPa (7.41 psi); 2-methylpentane 46.7 kPa (6.77 psi); cyclohexane 22.5 kPa (3.26 psi); and toluene 7.1 kPa (1.03 psi). 7

10. Calibration 10.1 Pressure Transducer: 10.1.1 Check the calibration of the transducer on a monthly basis or when needed as indicated from the quality control checks (see Section 11). The calibration of the transducer is checked using two reference points, zero pressure (<0.1 kPa) and the ambient barometric pressure. 10.1.2 Connect a McLeod gage to the vacuum source in line with the test chamber. Apply vacuum to the test chamber. W h e n the M c L c o d gage registers a pressure less than 0. I kPa (0.8 m m Hg), adjust the transducer control to zero or to the actual reading on the M c L c o d gage as dictated by the instrument design and manufacturer's instructions. NOTS 7--Refer to Annex A6 of Test Method D 2892 for further detailsconcerningthe calibrationof pressuresensorsand McLeodgages. 10.1.3 Open the test chamber of the apparatus to atmosphere and observe the corresponding pressure value of the transducer. Ensure that the apparatus is set to display the

818

NoTs 9--It is recommended that at least one type of control sample used in 11.1 be representative of the fuel(s) regularly tested by the laboratory. The total vapor pressure measurement process (including operator technique) can be checked periodicallyby performing this test method on previouslyprepared samples from one batch of product, as per procedure described in 8.1.2. Samples should be stored in an environmentsuitable for long term storase without sample degradation. Analysisof result(s)from these quality controlsamples can be carried out using control chart techniques,s 12. Procedure 12. I R e m o v e the sample from the cooling bath or refrigerator, dry the exterior of the container with absorbent material, uncap, and insert a chilled transfer tube or syringe 6 "Physical Constants of Hydrocarbon and Non-Hydrocarbon Materials," available from ASTM He~_dquarten. Order PCN 28-003092.12. The vapor preuure value~ cited were obtained from Phillips Petroleum Company, Bartlesville, Oklahoma or ASTM DS 4B Physical Constants of Hydrocarbon and Non-Hydrocarbon Compounds. s Reference ASTM MNL 7, Manual on Presentation of Data Control Chart Anal)sis, 6th Edition, Section 3: Control Chum for IndividuaB.

~

D 5191

(see 9.3). Draw a bubble-free aliquot of sample into a gas tight syringe or transfer tube and deliver this test specimen to the test chamber as rapidly as possible. The total time between opening the chilled sample container and inserting/ securing the syringe into the sealed test chamber shall not exceed 1 rain. 12.2 Follow the manufacturer's instructions for injection of the test specimen into the test chamber, and for operation of the instrument to obtain a total vapor pressure result for the test specimen. 12.3 Set the instrument to read the result in terms of total vapor pressure. If the instrument is capable of calculating a dry vapor pressure equivalent value, make sure that only the parameters in 13.2 are used.

13. Calculation 13.1 Record the total vapor pressure reading from the instrument to the nearest 0.1 kPa (0.01 psi). For instruments that do not automatically record a stable pressure value, manually record the pressure indicator reading every minute to the nearest 0.1 kPa. When three successive readings agree to within 0.1 kPa, record the result to the nearest 0.1 kPa (0.01 psi). 13.2 Calculate the dry vapor pressure equivalent (DVPE) using Eq 1. Ensure that the instrument reading used in this equation corresponds to the total pressure and has not been corrected by an automatically programmed correction factor: DVPE, kPa (psi) ffi (0.965 X) - A (1) where: X ~ measured total vapor pressure in kPa (psi), and A = 3.78 kPa (or 0.548 psi) NOTS 10--The correlation equation was derived from a statistical evaluation of the 1988 cooperative program.6 The equation corrects for the bias between the measured total vapor pressure and the dry vapor pressure obtained in accordance with Test Method D 4953. 13.3 The calculation described by Eq 1 can be accomplished automatically by the instrument, if so equipped, and in such cases the user shall not apply any further corrections.

15. Precision and Bias 9 15.1 Precision--The precision of this test method as determined by the statistical examination of interlaboratory test results is as follows: NOTE I l - - T h e following precision data were developed in a 1991 interlaboratory cooperative test program. Participants analyzed sample sets comprised of blind duplicates of 14 types of hydrocarbons and hydrocarbon-oxygenate blends. The oxygenate content (MTBE, ethanol,

and methanol) ranged from 0 to 15 % by volume nominal and the vapor pressure ranged from 14 to 100 kPa (2 to 15 psi) nominal. A total of 60 laboratories participated. Some participants performed more than one test method, using separate sample sets for each. Twenty-sixsample sets were tested by Test Method D 5190 and 27 by this test method. In addition, six sets were tested by modified Test Method D 5190 and 13 modified by this test method. 15.1.1 Repeatability---The difference between successive test results obtained by the same operator with the same apparatus under constant operating conditions on identical test material would, in the long run, in the normal and correct operation of the test method, exceed the value calculated as per Eq (2) only in one case in twenty: repeatability = 0.00807 (DVPE + B) (2) where: B = 124 kPa (or 18.0 psi).

15.1.2 Reproduciblity---The difference between two single and independent test results obtained by different operators working in different laboratories on identical test material would, in the long run, in the normal and correct operation of the test method, exceed the value calculated as per the following equation only in one case in twenty: reproducibility ffi 0.0161 (DVPE + B)

(3)

where: B ffi 124 kPa (or 18.0 psi). 15.2 Bias--Since there is no accepted reference material suitable for determining the bias for the procedures in this test method bias cannot be determined. 15.3 Relative B i a s n A statistically sitmificant relative bias was observed in the 1991 interlaboratory cooperative test program between the total pressure obtained using this test method and the dry vapor pressure obtained using Test Method D 4953, procedure A. This bias is corrected by the use of Eq. (1) (see 13.2), which calculates a DVPE value from the observed total pressure.

16. Keywords 16.1 Dry vapor pressure; gasoline; hydrocarbon-oxygenate blends; mini method; petroleum products; vapor pressure

14. Report

14.1 Report the dry vapor pressure equivalent to the nearest 0.1 kPa (0.01 psi) without reference to temperature.

9 The results of this test program are filed at ASTM Headquarters. Request RR:D02- ! 286.

819

41~ D 5191 The American Society for Testing and Materials takes no position respecting the validity of any patent rights melted In connection with any Item ~ In this standard. Users of this standard are expP,,eslyadvised that determination of the validity of any auch patent rights, and the risk of Infrlngeme~ of such rights, are entirely their own respopJIbllity. This Mandard is subject to revision at any time by the responsible technical committee and must he reviewed every five yesrs and If not revised, either reepproved or withdrawn. Yourcomments are Invited either for revision of this etandard or for eddIflonal standards and should be addressed to ASTM Hesdquartars. Your ¢ommants will receive careful consideration at a meeting of the responsible technical oummlttee, which you may attend. If you feel that your oumrnants have not received a fair hearing you should mske your views known to the ASTM Committee on Standards, 100 Barr Harbor Drive, West Conshohockon, PA 19428.

820

(1~ ~) Designation: D 5194 - 96 Standard Test Method for Trace Chloride in Liquid Aromatic Hydrocarbons 1 This standard is issued under the fixed designation D 5194; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (e) indicates an editorial change since the last revision or re.approval.

OSHA Regulations, 29 CFR, paragraphs 1910.1000 and 1910.12007

1. Scope 1.I This test method covers the determination of total chloride (organic and inorganic) in liquid aromatic hydrocarbons and cyclohexane. 1.2 The test method is applicable to samples with chloride concentrations of I to 25 mg/kg. 1.3 Bromides and iodides, if present, will be calculated as chlorides. 1.4 Materials, such as styrene, that are polymerized by sodium biphenyl reagent cannot be analyzed by this test method. 1.5 The following applies to all specified limits in this test method: for purposes of determining conformance with this test method, an observed value or a calculated value shall be rounded off "to the nearest unit" in the last right-hand digit used in expressing the specification limit, in accordance with the 'rounding-off method of Practice E 29. 1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For a specific hazard statement, see Section 7.

3. Summary of Test Method 3.1 A known amount of hydrocarbon sample is transferred into a separatory funnel containing toluene. Sodium biphenyl reagent is added to convert organic halogens into inorganic halides. The excess reagent is decomposed with water and the phases are separated. The aqueous phase is acidified, washed, and concentrated. Acetone is added and the solution is titrated with silver nitrate solution. 4. Significance and Use 4.1 Organic and inorganic chlorine compounds can have a deleterious effect on equipment and reactions in processes involving aromatic hydrocarbons. 4.2 Maximum chloride levels are often specified for process streams and for aromatic hydrocarbon products. 5. Apparatus 5.1 Titrator, potentiometric, recording, + 2000 mV range, 1 mV resolution with dispenser having a volume readout of 0.00 to 9.99 mL or 0.00 to 99.99 mL and 0.01% resolution. 5.2 Electrode, glass, reference. 5.3 Electrode, silver, billet type.

2. Referenced Documents

2. I A S T M Standards: D891 Test Method for Specific Gravity, Apparent, of Liquid Industrial Chemicals 2 D 1193 Specification for Reagent Water 3 D 3437 Practice for Sampling and Handling Liquid Cyclic Products 4 D 3505 Test Method for Density or Relative Density of Pure Liquid Chemicals 4 D 4052 Test Method for Density and Relative Density of Liquids by Digital Density Meter 5 E 29 Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications6 2.2 Other Documents:

6. Reagents and Materials 6.1 Purity of Reagents--Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, where such specifications are available) Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination. 6.2 Purity of WateruUnless otherwise indicated, references to water shall be understood to mean reagent water as defined by Types II or III of Specification D 1193. 6.3 Acetone, 99.9 % purity. 6.4 Congo Red Paper.

i This test method is under the jurisdiction of ASTM Committee I)-i6 on Aromatic Hydrocarbons and Related Chemicals and is the direct responsibility of Subcommittee DI6.0E on Instrumental Analysis. Current edition approved Feb. 10, 1996. Published April 1996. Originally published as D 5194 - 91. Last previous edition D 5194 - 91Et. 2 Annual Book of ASTM Standards, Vol 15.05. 3Annual Book of ASTM Standards, Vol 11.01. 4 Annual Book of ASTM Standards, Vo106.04. s Annual Book of ASTM Standards, Vol 05.02. 6 Annual Book of ASTM Standards, Vol 14.02.

Available from Superintendent of Documents, U.S. Government Printing Office, Washington, DC 20402. s Reagent Chemicals, American Chemical Society Specifications, American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed by the American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville, MD.

821

~]~

D 5194

6.5 Detergent. 9 6.6 Isobutanol, 99.9 % minimum purity. 6.7 Isooctane. 6.8 Nitric Acid, concentrated. 6.9 Nitric Acid, 5-M. Dilute 160 m L concentrated nitric acid to 500 mL with water. 6.10 Potassium Chloride, primary standard. 6.11 Potassium Chloride Solution, saturated. 6.12 Scouring Powder, cleanser. 6.13 Silver Nitrate, 99.99 % minimum purity. 6.14 Silver Nitrate Solution, 0.01 N, standardized to 0.1%. NOTE l--This solution may be obtained as follows: (1) Purchase from a laboratory supply company, (2) Weigh to four places, 1.680 to 1.720 g silver nitrate, transfer quantitatively into a 1000-mL volumetric flask, make to mark with water, and mix well. Normality of solution --

Weight AgNO3

169.9 or (3) Dissolve 8.5 g silver nitrate in 500 mL water to give a 0.1 N solution. Weigh0.09 to 0.10 g of dried (105"C)potassium chloride to the nearest 0.1 mg into a 250-mL electrolytic beaker, add 100 mL of water and a stirring bar. While stirring, titrate with the silver nitrate solution. Weight KC1 Normality of AgNO3 solution ffi 0.0746 × mL AgNO3 Pipet 50.00 mL of the solution into a 500-mL volumetric flask, dilute to mark with water, and mix well. Divide the calculated normality of the 0.1 N solution by 10 to give the normality of final AgNO3 solution. 6.15 Sodium Biphenyl Reagent, ~° The reagent is packed in 18-mL vials that contain 13 to 15 mg o f active sodium each. 6.16 Toluene, 99.9 % minimum purity. 7. Hazards

7.1 A material, such as styrene, which is polymerized by sodium biphenyl can cause a violent reaction and should never be used as the sample. 7.2 Consult current OSHA regulations and suppliers' Material Safety Data Sheets, and local regulations for all materials used in this test method. 8. Sampling 8.1 Refer to Practice D 3437 for proper sampling and handling of liquid hydrocarbons analyzed by this test method.

10. Procedure for Total Chloride 10.1 Extreme care must be used to prevent contamination and all glassware should be exclusively reserved for this analysis. Just prior to use, the glassware should be rinsed with water followed by acetone and then air dried. 10.2 Place 50 mL of toluene into a 250-mL separatory funnel and pipet in the amount of the liquid sample that corresponds to the estimated chloride content as prescribed in Table 1. NOTE 2--It is generally more convenient to measure the liquid samples by volume and then convert to mass using density or relative density. Table 2 lists the relative densities of several pure hydrocarbons. Densities of unknowns may be determined by using Test Methods D 891, D 3505 or D 4052. NOTE 3--Alternately, place the sample into a 125-mL bottle and weigh. From the contents of this bottle add the appropriate amount of the sample to the toluene in the separatory funnel. Reweigh the bottle, and determine the weight of the analytical specimen. 10.3 Add the contents of one vial of sodium biphenyl reagent, stopper the separatory funnel, and gently swirl to mix thoroughly, venting the funnel from time to time. If the resulting solution or suspension is not blue-green, add more sodium biphenyl reagent (one vial at a time) until the blue green color persists. NOTE 4--The sodium biphenyl reagent has a limited shelf life, given as six months by the manufacturer. This can be extended, in most cases, to approximately one year by keeping the reagent under refrigeration. If this is done, the reagent should be kept at room temperature for several days just prior to use to dissolve any sodium bipbenyl that may have precipitated upon cooling. 10.4 Allow the mixture to stand for approximately 10 rain. Slowly add 20 m L water and swirl gently with the funnel unstoppered until the blue-green color changes to white. Stopper the funnel again and rock it gently for 1 rain, venting the pressure frequently through the stopcock. 10.5 Add 10 mL 5 N nitric acid, and then 5 mL isobutanol. Shake gently, releasing the pressure frequently through the stopcock. 10.6 Drain the aqueous phase into another 250-mL separatory funnel containing 50 mL isooctane and shake well. Drain the aqueous phase into a 250-mL electrolytic beaker. 10.7 Make a second extraction of the specimen solution with 20 mL water acidified with 6 drops of 5-M nitric acid and drain the aqueous phase into the separatory funnel

9. Electrode Preparation TABLE 1 Specimen Size Estimated chloride,mg/kg Specimen volume,mL 0to5 100 5 to 25 50

9.1 Clean the surface of the silver electrode with mild detergent and scouring powder, and rinse with water. 9.2 Immerse the electrode in the saturated potassium chloride solution until the electrode tip turns light gray. 9.3 Rinse well with water and attach to the titrimeter. 9.4 Repeat the electrode preparation when the silver chloride film begins to peel from the surface, or if the film becomes discolored. 9Detergentsuchas AiconoxavailablefromFisherScientific, 1600W. Glendale Ave., ltasca, IL 60143, CatalogNo. 04-322, has been foundsatisfactoryfor this purpose. to Sodiumbiphenylreagent, available fromSouthWestern AnalyticalChemicals, P.O. Box 485, Austin TX 78767, Catalog No. 500, "Organic Halogen Reagent,"or equivalenthas been foundsuitable for this purpose. 822

TABLE 2 Densities of Hydrocarbons Component Density Benzene 0.879 Cyc.Johexene 0.779 Ethylbenzene 0.867 Isopropylbenzene 0.864 Toluene 0.866 m-Xylene 0.864 o-Xylene 0.880 p-Xylene 0.861

~

D 5194 A B N V D

= volume of titrant for aqueous phase, mL, --- volume of titrant for blank, mL, = normality of silver nitrate solution, = volume of sample, mL, and = density or relative density of sample. 13.2 Calculate organic chloride as follows: Organic chloride, mg/kg -- T - I where: T = total chloride, mg/kg and I = inorganic chloride, mg/kg. 13.3 Report chloride to the nearest 0.1 mg/kg.

containing the isooctane. After shaking, allow the phases to separate and drain the aqueous phase into the beaker containing the first water extract. 10.8 Test the aqueous solution with Congo red paper, and if it does not test acidic, add 5-N nitric acid dropwise with stirring until the test paper turns dark blue. 10.9 Evaporate the solution to about 30 mL on a hot plate. NOTE 5--Caution--Loss of chloride may result if the solution is boiled or evaporated below 25 mL.

10.10 Allow the solution to cool, and add 100 mL of acetone. Titrate the solution potentiometrically with standard 0.01 N silver nitrate solution and determine the volume of titrant used to reach the end point. I0.11 Determine a blank for each group of samples, using all the reagents including as many vials of sodium biphenyl as were used in the analysis of a sample. Follow all the operations of the analysis, except omit the specimen itself.

14. Precision and Bias

14. l Precision: 14. I. l The data for determining the precision of this test method are based on the analyses of toluene, ethylbenzene, and p-xylene that had been spiked with organic chloride compounds to the l, 5, and 25 mg/kg chloride levels each. 14.1.2 The following criteria should be used to judge the acceptability (95 % probability) of results obtained by this test method. The criteria were derived from a round robin between three laboratories. Each sample was run on two different days in each laboratory. 14.1.2.1 Intermediate Precision (formerly called Repeatability)--Results in the same laboratory should not be considered suspect unless they differ by more than 0.5 mg/kg. 14.1.2.2 Reproducibility--Results from each of two laboratories should not be considered suspect unless they differ by more than 0.9 mg/kg. 14.2 Bias--The bias of this test method cannot be determined because no referee method is available to determine the true value.

11. Procedure for Inorganic Chloride 11.1 Follow the procedure in Section 10 but without adding the sodium biphenyl reagent to either the sample or the blank. 12. Procedure for Organic Chloride 12.1 Follow the procedures given in Sections I0 and 11 to determine the total and inorganic chlorides. Subtract the inorganic from the total chloride to give the organic chloride. 13. Calculation 13.1 Calculate either the total or inorganic chloride as follows: Chloride, mg/kg = 35,500 (A - B) N vD

(2)

15. Keywords 15.1 aromatic hydrocarbons; ethylbenzene; p-xylene; toluene

(1)

where:

chloride;

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted In connection with any item mentioned In this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reepproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consldarat/on at e meeting of the responsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 100 Barr Harbor Drive, West Conshohockan, PA 19428.

823

cyclohexane;

(t~1~ Designation: D 5234 - 92 Standard Guide for Analysis of Ethylene Product 1 This standard is issued under the fixed designation D 5234; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (~) indicates an editorial change since the last revision or reapproval.

1. Scope 1.1 This guide provides direction for the analysis of ethylene product in a way that allows the analyst to know the possible test methods, the units of measure, and the potential concentrations range of possible components, so that the consistency of the analytical measurements is improved. This guide is not intended to be used, nor to be construed in any way, as a set of specifications for ethylene product. 1.2 The values stated in SI units are to be regarded as the standard. 1.3 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

2. Referenced Documents 2.1 A S T M Standards: D 2504 Test Method for Noncondensable Gases in C2 and Lighter Hydrocarbon Products by Gas Chromatography 2 D 2505 Test Method for Ethylene, Other Hydrocarbons, and Carbon Dioxide in High-Purity Ethylene by Gas Chromatography 2 D3246 Test Method for Sulfur in Petroleum Gas by Oxidative Microcoulometry2 D 4178 Practice for Calibrating Moisture Analyzers3 D 4468 Test Method for Total Sulfur in Gaseous Fuels by Hydrogenolysis and Rateometric Colorimetry4 F 307 Practice for Sampling Pressurized Gas for Gas Analysis5 3. Terminology 3.1 Definition: 3.1.1 ethylene product, n--hydrocarbon product containing at least 99.85 % mass ethylene. 3.2 Symbols: 3.2.1 C4s, n--saturated and unsaturated four carbon hydrocarbon compounds. 3.2.2 COS, n--carbonyl sulfide. 3.2.3 GC, n--gas chromatograph. 3.2.4 FPD, n--flame photometric detector. i This guide is under the jurisdiction of ASTM Committee I)-2 on Petroleum Products and Lubricants and is the direct responsibility of Subeornmittee D02.D0.01 on C2 Test Methods. Current edition approved Aug. 15, 1992. Published October 1992. 2 Annual Book of A S T M Standards, Vol 05.02. 3 Annual Book of A S T M Standards, Vol 05.03. 4 Annual Book of A S T M Standards, Vol 05.05. s Annual Book of A S T M Standards, Vol 10.05.

3.2.5 IC, n--ion chromatograph. 3.2.6 MeOH, n--methanol. 3.2.7 NO, n--nitric oxide. 3.2.8 NO2, n--nitrogen dioxide. 3.2.9 02, n--oxygen. 3.2.10 sp. ion electrode, n--specific ion electrode.

4. Significance and Use 4.1 When the various producers and users of ethylene product deal with the results obtained in analytical testing, inconsistency of units and test methods may cause major errors. This guide provides an overview of the typical concentrations of the possible components found in ethylene product, the methods used in analysis, and the units of measure. This overview is intended to be used to improve the consistency of methods and the units reported so that errors are minimized. Each producer and user of ethylene product should immediately review this guide to improve their awareness of the various analytical methods in use, the units of measure, and concentration levels of the possible components. 4.2 Although this guide is not to be used for specifications, it can provide a starting point for the various parties to develop mutually agreed upon specifications that meet their respective requirements. It can also be used as a starting point in finding suitable test methods for ethylene components. 5. Sampling 5.1 In general, sample ethylene product using Practice F 307, or a similar method. Do not take liquid ethylene samples in order to prevent over-pressuring of sample containers and elimination of fire and explosion hazards. Static electricity can develop when discharging excess hydrocarbon at a fairly rapid rate from a sample cylinder to ambient conditions. Use a grounding system or strap. 5.2 Reactive and Polar Components: 5.2.1 Determination of reactive components, such as certain sulfur compounds, is generally believed to require special sample containers, such as fluorocarbon lined cylinders, or containers that have been specially passivated. 5.2.2 It is very difficult to obtain a valid sample for determination of traces of polar compounds, such as water and ammonia, in the laboratory. On-line analyzers, if available, or adsorption of the analyte at the sample source for subsequent lab finish are believed to yield the most accurate results. 6. Composition and Test Methods 6.1 Table 1 indicates possible composition ranges and ASTM test methods for ethylene product.

824

~

O 5234

Ethylene Test Methods (ASTM)

TABLE 2

Component

Concentrations

Units

Test Methods

Components

Possible Test Methods

Ethylene Ethane Methane Propylene Propane Hydrogen Carbon monoxide Carbon dioxide Acetylene Moisture AlcohOls Total sulfur Oxygen Nitrogen Ammonia Hydrogen sulfide Carbonyl sulfide Total oxygenates NO and NO2 Benzene C4s Methyl acetylene Propadiene Chlorides

99.85 + 200 to 700 <0,1 to 200 <0.1 to 10 <0.1 to 5 <0.1 to 10 <0.1 to 5 <0.1 to 10 <0.1 to 5 <0.1 to 5 <0.1 to 5 <0,1 to 5 <0.1 to 3 <1 to 10 <0.1 to 2 <0.1 to 1 <0,1 to 1 <0.1 to 10 <0.1 to 10 <0.1 to 10 <0.1 to 10 <0.1 to 10 <0.1 to 10 <0.1 to 2

~=mass mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg rng/kg

D 2505 D 2505 D 2505 D 2505 D 2505 D 2504 D 2504 D 2504 D 2505 See Table 2 See Table 2 D 3246 or D 4468 D 2504 or O= meter D 2504 See Table 2 Online analyzer See Table 2 See Table 2 See Table 2 See Table 2 See Table 2 See Table 2 See Table 2 See Table 2

Methane, ethane propane, propylene, propediene, methyl acetylene, acetylene

An adaptation of Test Method D 2505 is used by some labs. Others use a GC wide-bore capillary method. New technology offers narrow bore capillariesthat separate all hydrocarbons in one analysis. An adaptation of Test Method D 2504. An adaptation of Test Method D 2505. Chemiluminescence. Some labs use an adaptation of Test Method D 3246; others use Test Method D 4468 with an oxy-hydrogen pyrolyzer. GC methods including wide bore capillary. Obtaining a valid sample for lab analysis is extremely difficult, Instead of e lab method, an ASTM study group beveloped, in 1982, a standard practice for calibrating moisture analyzers, Practice D 4178. Several types of portable end on-line analyzers are available. GC methods including wide bore capillary. Some methods in use are: Acid absorption/Nessler finish. Acid absorption/specific ion electrode. Acid absorption/IC finish, GC methods. GC methods ~nuse. Wide bore capillary GC methods. GC--FPD method, Hall conductivity detector.

TABLE 1

H2, N2, O2, and CO CO2 NO and NO2 Total sulfur Benzene Moisture

C4s Ammonia

Total oxygenates Alcohols

6.2 Table 2 lists other test methods known or believed to be in use.

COS Chlorides

Ethylene Test Methods (Non-ASTM)A

A This table gives possible ethylene test methods or techniques that are believed to be In use in the Industry for testing, Inclusion of any test method in this table is not to be construed as a recommendation by ASTM for its use. Some of the test methods In this list are ASTM test methods that are specified for other products, but are being used by some labs for ethylene analysis. However, use of ASTM test methods beyond their scope is not recommended by ASTM. Precision and bias may be adversely affected.

7. Keywords 7.1 ethylene; ethylene product concentration; ethylene test methods

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard, Users of this standard are expressly edv/sod that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reepproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend, ff you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103.

825

(1~

Designation: D 5236 - 95

Standard Test Method for Distillation of Heavy Hydrocarbon Mixtures (Vacuum Potstill Method) 1 This standard is issued under the fixed designation D 5236; the number immediately following the designation indicates the year of original adoption or, in the ease of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (E) indicates an editorial change since the last revision or reapproval.

responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific warnings see Notes 2, 3, and 4.

1. Scope 1.1 This test method describes a procedure for distillation of heavy hydrocarbon mixtures having initial boiling points greater than 150"C (300*F), such as heavy crude oils, petroleum distillates, residues, and synthetic mixtures. It employs a potstill with a low pressure drop entrainment separator operated under total takeoff conditions. Distillation conditions and equipment performance criteria are specified and typical apparatus is illustrated. 1.2 This test method details the procedures for the production of distillate fractions of standardized quality in the gasoil and lubricating oil range as well as the production of standard residua. In addition, it provides for the determination of standard distillation curves to the highest atmospheric equivalent temperature possible by conventional distillation. 1.3 The maximum achievable temperature, up to 565"C (1050*F) atmospheric equivalent temperature (AET), is dependent upon the heat tolerance of the charge. 1.4 The recommended distillation method for crude oils up to outpoint 400"C (752"F) AET is Test Method D 2892. This test method can be used for heavy crude oils with initial boiling points greater than 150"C (302"F). However, distillation curves and fraction qualities obtained by these methods are not comparable. 1.5 This test method contains the following annexes: 1.5.1 Annex A1--Test Method for Determination of the Temperature Response Time, 1.5.2 Annex A2--Practice for Calibration of Temperature Sensors, 1.5.3 Annex A3--Practice for Calibration of Pressure

2. Referenced Documents

2.1 ASTM Standards: D941 Test Method for Density and Relative Density (Specific Gravity) of Liquids by Lipkin Bicapillary Pycnometer2 D 1217 Test Method for Density and Relative Density (Specific Gravity) of Liquids by Bingham Pycnometer2 D 1250 Guide for Petroleum Measurement Tables (Description only; tables published separately in 12 volumes)2 D 1298 Practice for Density, Relative Density (Specific Gravity), or API Gravity of Crude Petroleum and Liquid Petroleum Products by Hydrometer Method 2 D 1480 Test Method for Density and Relative Density (Specific Gravity) of Viscous Materials by Bingham Pycnometer2 D 2892 Test Method for Distillation of Crude Petroleum (15-Theoretical Plate Column) 3 D 4057 Practice for Manual Sampling of Petroleum and Petroleum Products 3 D 4177 Practice for Automatic Sampling of Petroleum and Petroleum Products 3 D 5002 Test Method for Density and Relative Density of Crude Oils by Digital Density Analyzer4 3. Terminology 3.1 Descriptions of Terms Specific to This Standard: 3.1.1 boil-up rate, n--the quantity of vapor entering the distillation head per unit time. 3.1.1.1 Discussion--It is approximately equal to the takeoff rate differing only by the parasitic heat losses. It is expressed in millilitres per hour for a head of any given internal diameter or millilitres per hour per square centimetre of cross-sectional area of the throat for comparative purposes. 3.1.2 condenser, n--the apparatus connected to the outlet of the distillation head in which condensation of the product

Sensors,

1.5.4 Annex A4--Test Method for Dehydration of a Wet Sample of Oil, 1.5.5 Annex A5--Practice for Conversion of Observed Vapor Temperature to Atmospheric Equivalent Temperature (AET), and 1.5.6 Annex A6--Test Method for Determination of Wettage. 1.6 The values stated in SI units are to be regarded as the standard. The inch-pound units given in parentheses are provided for information purposes only. 1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the

OCCUrs.

3.1.3 distillation flask, n--the flask, of glass or metal, in which the charge is boiled.

' This test method is under the jurisdiction of ASTM Committee 13-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.08.0C on Crude Distillation. Current edition approved Dec. 10, 1995. Published May 1996. Originally published as D 5236 - 92. Last previous edition D 5236 - 92.

2 Annual Book of ASTM Standards, Vol 05.01. 3 Annual Book of ASTM Standards, Vol 05.02. 4 Annual Book of ASTM Standards, Vol 05.03.

826

t~ D 5236 soaking that occurs in this test method may alter some of the properties. Note I--While reblendingof distillates with residue can be done to produce a lighter residue, this practice is not recommended because it produces blends with irregularproperties.

3.1.3.1 DiscussionDThe flask is sometimes called a kettle or pot. 3.1.4 distillation head, n ~ t h e section immediately above the distillation flask containing the entrainment separator. 3.1.5 distillation pressure (or operating pressure), n--the pressure measured in the distillation head just before the outlet to the recovery system. 3.1.6 distillation temperature (or vapor temperature), n ~ the temperature of the vapors in the distillation head at the point of measurement. 3.1,7 loading, n ~ t h e volume of charge relative to the cross-sectional area of the neck. 3.1.8 pressure drop, n ~ t h e difference between the operating pressure and the pressure measured in the distillation flask. 3.1.8.1 DiscussionDIt is a result of the friction developed by driving the vapors through the system expressed in kilopascals (mm Hg). 3.1.9 spillover point, n ~ t h e lowest point in the head above the entrainment separator over which the vapors can flow to the condensing region. 3.1.10 static hold-up (or wettage), n ~ t h e amount of liquid material remaining on the inside of the walls of the apparatus after the distillation has been completed. 3.1.10.1 Discussion~In this test method it includes wettage of the distillation flask in the case of the steel flasks, but not in the case of glass flasks that are removed for weighing after the distillation is completed. 3.1. I 1 takeoff rate, n ~ t h e quantity of product removed per unit time. 3.1.11.1 DiscussionDIt is approximately equal to the boil-up rate differing only by parasitic heat losses.

5.4 Details of cut points must be mutually agreed upon before the test begins. 5.5 This is a complex procedure involving many interacting variables. It is most important that at the time of first use of a new apparatus, its components be checked as detailed in Annexes A 1, A2 and A3 and that the location of the vapor temperature sensor be verified as detailed in 6.5.3 and Fig. 1. 6. Apparatus 6.1 Four sizes of apparatus, based upon the internal diameter of the distillation head (25, 36, 50 and 70-mm), are allowed, s The apparatus (Fig. 2) consists of a flask with heating mantles and upper compensator and a head containing an entrainment separator. Attached to the head is the vapor temperature sensor, a connection for the vacuum gage, a condenser, a rundown line, product receiver(s), and a vacuum pumping line with pump. The parts are connected by vacuum-tight joints to facilitate servicing. 6.2 Distillation Flask: 6.2.1 The sizes specified for flasks are at least 50 % larger than the size of the charge to provide space for suppression of foam and for bubble breaking. The size of the charge for each size of still is determined from the loading factor. The recommended loading factor is between 200 and 400 mL of charge per square centimetre of cross sectional area in the neck of the head. Table 1 shows the range of charge volume that is recommended with each size of apparatus. 6.2.2 Flasks are made of borosilicate glass except those larger than 10 L which are made of stainless steel for reasons of safety. 6.2.3 The flask is fitted with a thermowell reaching to within 6 m m of the bottom and offset from the center to avoid a stirring bar. In the case of glass flasks, the bottom shall be slightly flattened or slightly concave, but not perfectly flat to facilitate the rotation of the magnetic stirrer. Steel flasks can have a cooling coil for rapid quenching of the distillation in an emergency. Figure 3 shows a typical example. 6.3 Stirring SystemDA magnetically driven stirring bar approximately 3 m m diameter and 20 mm long shall be provided for the glass flasks, or 6 mm diameter by 50 mm long for the steel flasks. The edges shall be rounded to minimize grinding the wall of the flask. The external magnetic drive must be capable of rotating the bar in the flask when located directly below and touching the mantle. The drive can be used to support the apparatus above. An adjustable jacking mechanism is recommended for raising and lowering the stirrer. 6.4 Heating System: 6.4.1 The flask shall be heated by means of a nickel reinforced quartz fabric heating mantle on the lower half so that boiling rates of up to 150 mL/h per cm 2 of cross

4. Summary of Test Method 4.1 A weighed volume of sample is distilled at absolute pressures between 6.6 and 0.013 kPa (50 and 0.1 mm Hg) at specified distillation rates. Cuts are taken at preselected temperatures. Records of vapor temperature, operating pressure and other variables are made at intervals, including at each cut point. 4.2 The mass of each fraction is obtained. Distillation yields by mass are calculated from the mass of each fraction relative to the total mass recovery. 4.3 The density of each fraction is obtained. Distillation yields by volume are calculated from the volume computed for each fraction at 15"C (59"F) relative to the total recovery. 4.4 Distillation curves of temperature versus mass or volume percent, or both, are drawn using the data from 4.2 and 4.3. 5. Significance and Use 5.1 This test method is one of a number of tests conducted on heavy hydrocarbon mixtures to characterize these materials for a refiner or a purchaser. It provides an estimate of the yields of fractions of various boiling ranges. 5.2 The fractions made by this test method can be used alone or in combination with other fractions to produce samples for analytical studies and quality evaluations. 5.3 Residues to be used in the manufacture of asphalt can also be made but may not always be suitable. The long heat

5 Cooke, Industrial and Engineering Chemistry, Vol 55, 1963, p. 36.

827

t@) D 5236

I !

('!I

c

2\

)

/~

s .....

~

)

,

"1

-.::,'r';?~: '. ,',",,',,'" ....... -

°-

-

II--

T-,

-~ -"~ ~

STILl. HEAD DIMENSION CHART Size

A

B

C

25 mm

85 mm

75 mm

64 mm

47 mm ID

D

E

F

G

H

I

40 mm OD

4 - 5 mm

35/25

28/15

35 mm

36 mm

90 mm

75 mm

64 mm

68 mm ID

57 mm OO

5 - 6 mm

65/40

35/25

35 mm

50 mm

110 mm

100 mm

75 mm

94 mm ID

79 mm OD

7 - 9 mm

75/50

35/25

45 mm

70 mm

140 mm

100 mm

100 mm

131 mm ID

111 mm OD

10-11 mm

102/75

50/30

70 mm

FIG. 1

Distillation H e a d

sectional area of the neck can be maintained. A heat density of 0.5 W/cm 2 is adequate. Usually two or more circuits are used to improve heat control by applying automatic heat to the bottom circuit. 6.4.2 A temperature sensor shall be located between the wall of the flask and the mantle for control of the skin temperature. 6.4.3 The upper half of the flask shall be covered with a mantle to compensate for heat losses. A heat density of 0.2 W / c m 2 is adequate. 6.5 Distilling Head: TABLE

1

6.5.1 The head shall conform to the details shown in Fig. 1. It shall be made of borosilicate glass and be totally enclosed in a silvered glass vacuum jacket having a permanent vacuum of less than 0.0001 kPa (0.00075 mm Hg). 6.5.2 The head shall be enclosed in a heat insulating system such as a glass fabric mantle capable of maintaining the outer wall of the glass vacuum jacket at a temperature 5"C below the internal vapor temperature in the head. For this purpose the vacuum jacket shall have a temperature sensor fastened to the outer wall of the jacket at a point level with the vapor temperature sensor and opposite to the outlet arm of the head. 6.5.3 The head shall be fitted with an adapter to support the vapor temperature sensor so that it is held centered in the neck with the top of the sensing tip 3 _+ 1 mm below the spillover point. This dimension can be checked by removing the temperature sensor and inserting in its place a copper wire having a short right angle bend at the bottom. By feeling for the spillover point, the distance from the top joint of the adaptor can be found. Laying the wire on the temperature

Standard Charge and F l a s k S i z e

Inside Diameter, mm

Throat Cross-Sectional Area, crn=

Charge, L

Flask, L

25 36 50 70

5 10 20 40

1-2 2-4 4-8 8-16

2-3 3-6 6-12 12-24

828

o s2a6 A

TO VACUUM PUMPING LINK

HEAD TRAp ~/I

T~N VACUUM GAUGE

CONDINSEH--~

THERMOCOUPLE B

4--------- HEAD HEAD COHPENSATIHG ~ANTLE (not shown)

VACUUM ADAPTER

FLASK THERMOCOUPLE

/-

FLASK MANTLES

SYSTEM SIZE

DISTILLATION

MAGNETIC 8TIRHER

FIG. 2

Apparatus

25 mm

35/25

3L

36 mm

65/40

6L

50 mm

75/50

12 L

70 mm

102/75

24 L

FIG. 3

sensor will then permit checking of this dimension. 6.5.4 The vapor temperature sensor shall be either a platinum resistance thermometer having a resistance on 100 ohms at 0*C, or a Type J thermocouple with the junction bead fused to the lower tip of the well. In either case, it shall have a response time of less than 1 min as described in Annex A1 and must be capable of reading to the nearest 0.5"C (I'F). 6.5.5 The vapor temperature sensors shall be calibrated with their associated instruments at the time of first use and at least once per month thereafter as described in Annex A2. 6.5.6 A head trap as illustrated in Fig. 4 shall be fitted to the adapter described in 6.5.3 for connection to the vacuum sensor. It shall be kept filled with crushed dry ice at all times while in service. 6.5.7 A vacuum sensor shall be connected to the sidearm of the trap. The sensor must be capable of reading the pressure with a precision equal to or better than 1% of the pressure employed, or equal to or better than 0.00133 kPa (0.01 mm Hg), whichever is greater. The McLeod gage can achieve this accuracy when properly used, but a mercury manometer will permit this accuracy only down to a pressure of about 1 kPa and then only when read with a good cathetometer (an instrument based on a telescope mounted on a vernier scale to determine levels very accurately). An electronic gage such as the Baratron is satisfactory when

Distillation Flask

. ='.V." 0=

FIG. 4

..

o

Head Trap and Temperature Sensor

calibrated from a McLeod gage but must be rechecked periodically as described in Annex A3. A suitable pressure calibration setup is illustrated in Fig. A3.1. Vacuum gages 829

D 5236

7

D

# **~llt

~l,

I

diameter of the pumping line shall be connected between the surge tank and the vacuum pump. 6.7.4 A dewar type trap made of borosilicate glass, such as that illustrated in Fig. 5, shall be placed between the top of the distillation head and the vacuum sensor. It shall be kept filled with crushed dry ice at all times during the distillation to protect the vacuum system from contamination with residual vapors. 6.8 Vacuum Source~A single stage mechanical vacuum pump capable of maintaining a steady pressure in the system at all operating pressures shall be connected to the pumping line. Automatic or manual control can be used. 6.9 Recovery System: 6.9.1 The recovery system is connected to the lower outlet of the product condenser and consists of a vacuum adapter to permit removal of distillate receivers without disturbing the pressure in the system. A suitable manual device is illustrated in Fig. 6. 6.9.2 Alternatively, either automatic or manual devices can be used to collect part or all of the fractions within the

II

/

IB

C

C

,,,..o,

..,, , . , . . , . , , , o

°/

\

\ CONDENSER DIMENSION CHART

B

c

25 mm

51 mm

28 mm

300 mm

35/25

36 mm

75 mm

45 mm

300 mm

65/40

50 mm

80 mm

54 m m

400 mm

75•50

70 mm

120 mm

80 mm

400 m m

102/75

S y s t e m Size

[

A

FIG. 5

I

Condenser

based on hot wires, radiation, or conductivity detectors are not recommended. NOTE 2--Suitable instruments for measuring the pressure of the system during the test arc the tensimetcr or an electronic pressure gage, provided the output is traceable to a primary gage, such as the non-tilting Mcleod gage. 6.6 Condenser--A condenser made of borosilicate glass, shall be connected to the outlet arm of the head (Fig. 5). It shall have sufficient capacity to condense essentially all vapors and capable of operating at coolant temperatures up to 700C to prevent wax buildup. 6.7 Pumping Line: 6.7.1 A pumping line shall be connected from the outlet of the condenser to the vacuum pump. The pumping line can be made of heavy-walled rubber or light metal tubing but its inside diameter must be greater than half the inside diameter of the outlet of the condenser and less than 2 m long. 6.7.2 A surge tank of a size at least equal to the capacity of the flask shall be inserted in the pumping line adjacent to the pump. 6.7.3 An isolation valve of a diameter at least equal to the

I #

INTERMEDIATE RECEIVER DIMENSION CHART

System Size

A

B

C

25 mm

45 mm

120 mm

35/25

36 mm

51 mm

120 mm

35/25

50 mm

64 mm

150 mm

50/30

70 mm

75 mm

150 mm

50/30

FIG. 6

830

Receiver System

~) TABLE 2 Operating Pressure, kPa (turn Hg) 6.67 (50) 1.33 (10) 0.133 (1) 0,0400 (0.3) 0.0133 (0.1)

D 5236

Operating Pressures and Distillation Rates

Boil-Up Rate, mL/ (h. x .em2)

25 mm

36 mm

50 mm

70 mm

90-150 75-125 45-75 30-50 10-20

450-750 375-625 225-375 150-250 50-100

900-1500 750-1250 450-750 300-500 100-200

1800--3000 1500-2500 900-1500 600-1000 200-400

3600-6000 3000-5000 1600-3000 1200-2000 400-800

Take-Off Rate, mL/h

following test methods: Test Methods D941, D 1217, D 1480, D 5002, or Practice D 1298. Refer to Guide D 1250 to correct densities to 15"C. 9.2 Insert the stirring bar. 9.3 From Table l, determine the volume of the charge and calculate the mass to be charged by multiplying its density by the desired volume. 9.4 Weigh this mass of charge into the flask to the nearest 0.1%. In the case of flasks too large to handle, the flask can be put in place and the charge drawn in from a container (weighed with its transfer line) using a pressure of 90 to 95 kPa in the still. The charge may need to be warmed to facilitate transfer. Its mass can be determined from the difference. 9.5 Attach the flask to the column (in the case of smaller flasks), and put on all the heating mantles. Put the stirring device in place and turn it on.

system without disturbing the operating pressure until the end of the run. Heating must be provided when needed to maintain the product in the liquid state. 6.9.3 The product receivers shall be made of borosilicate glass and of a size convenient for the size of the fractions to be collected. They shall be calibrated to the nearest 1% from the bottom. Nor~ 3: WarningmThis apparatus operates under high vacuum and high temperature. It is recommended that these stills be kept in an enclosure to ensure that in case of an implosion, the operator and others nearby are protected from flying debris, but that the front, at least, be transparent and removable for access to controls etc. Automated stills, which are lefl unattended for long periods, should be equipped with an automatic fire extinguisher, automatic quench and alarm.

7. Sampling 7. I Obtain the sample for distillation in accordance with instructions given in Practice D4057 or Practice D 4177. The sample can also be a residue from Test Method D 2892. 7.2 The sample must be in a closed container when received and show no evidence of leakage. 7.3 If the sample looks waxy or has solidified, warm it enough to liquify it and ensure that it is thoroughly mixed before using. 7.4 If, upon examination, there is evidence of water in the sample, perform a preliminary distillation as described in Annex A4.

NffrE 4: Caution--Ensure that the safety shield is in place.

9.6 Apply heat to the flask at a rate that will raise the temperature of the charge quickly, but no faster than 300"C/h (540"F/h). Do not exceed a skin temperature on the flask of 400"C (750"F) or cracking may result on the walls of the flask. NOTE 5: Caution--Some hydrocarbon mixtures cannot tolerate 400"C for any useful length of time. Reducingthe skin temperature may be necessaryin these cases.

8. Preparation of Apparatus

9.7 Turn on the head compensation mantle and maintain the outer wall of the glass vacuum jacket at a temperature approximately 40"C below the temperature of the liquid in the flask. 9.8 Reduce the pressure in the system gradually to a suitable starting pressure. Choose from Table 2 the highest pressure that is consistent with the expected initial boiling point and maximum cutpoint using Fig. 7 as a guide. A pressure of 0.133 kPa ( 1.0 mm Hg) has been found satisfactory for starting a material having an initial boiling point of 343"C (650°P0 AET, such as residues from Test Method D 2892 distillations.

8.1 Clean and dry all glass parts and assemble them with freshly lubricated joints as shown in Fig. 2. In the case of ball joints use only enough lubricant to produce a thin continuous film. An excess of lubricant can promote leakage. The rings of O-ring joints should be made of Vitron-A 6 or silicone of equivalent hardness and be lightly lubricated. 8.2 Tare the receivers to the nearest 0.1% of the weight of the charge. 8.3 To check for leaks, pump the system down to a pressure of approximately 0.05 kPa (0.4 mm Hg) and isolate it from the vacuum source. If after 1 rain, if the rise in pressure is no greater than 0.01 kPa (0.075 mm Hg), the system is acceptable. If the rise in pressure is greater than 0.01 kPa (0.075 mm Hg) in 1 min, the gage and its connections must be examined and leaks corrected before proceeding. 8.4 Calibrate the temperature and pressure sensors as described in Annexes A2 and A3.

NOTE 6--Degassing of the charge is sometimes evident before the

actual distillationbegins. This appears as bubbling at the surfacewithout generation of condensible vapors. 9.9 When distillation begins, evidenced by vapors entering the neck of the flask, reduce the heat input to a level which will maintain the chosen distillation rate from Table 2 (see Note 6). Adjust the heat compensator on the head to maintain the outer wall of the glass vacuum jacket at a temperature 5"C below the vapor temperature.

9. Procedure 9.1 Determine the density of the sample by one of the

NOTE 7--Although a range of distillation rates is permitted, 80 % of the maximum allowed is recommended.

6 Vitron A is a registered trademark of DuPont E,I. De Nemours and Company, Wilmington, DE 19898.

9.10 In cases where the observed initial vapor temperature 831

(@) D 5236

ll

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180

200

2~1) 240

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400

42~

450

OBSERVED TENPIERAT1JI~. "C

FIG. 7

Correction of Vapor Temperature to Atmospheric Equivalent

9.12.1 Time in hours and minutes, 9.12.2 Volume of distillate in millilitres, 9.12.3 Vapor temperature to nearest 0.5°C, 9.12.4 Liquid temperature in the flask in °C, 9.12.5 Pressure in the head to nearest 1%, and 9.12.6 Atmospheric equivalent temperature by calculation as prescribed in Annex A5. 9.13 Continue taking product and making cuts until the final cutpoint is achieved or until the temperature in the boiling liquid reaches approximately 290°C (554"F). 9.14 At this point, if the final cutpoint cannot be achieved before reaching 3200C (608°F) in the boiling liquid, reduce the heat input to zero until the distillation slows. This will take 2 to 10 min depending on the amount of material in the flask. Reduce the pressure slowly to the next lower pressure level. 9.15 Restore the heat to about 90 % of the previous level and then adjust to give the desired rate at the lower level (see Table 2). Do not take any cuts until the pressure has stabilized at the new level for at least 2 min.

will be 150"C (302"10 or lower, it is desirable to refrigerate the first fraction receiver to ensure the retention of light ends. If solid waxy material appears on the walls, warm the receiver with an infrared heat lamp or hot air gun to liquify the product in the receiver in order to improve the accuracy of the reading. In automatic operation, the receivers must be thermostatted at a temperature high enough to ensure that no solidification takes place and low enough to prevent evaporation of light material. 9.11 When the receiver is full, or when a cut point is reached, isolate the receiver, or move to the next one as the case may be. 9.11.1 In manual operation, isolate the receiver using the vacuum adaptor and vent it to atmospheric pressure before replacing it with another tared receiver. Apply vacuum and when the new receiver is at approximately system pressure, reconnect it to the system. 9.11.2 In automatic operation, receivers are changed automatically and do not normally need further attention. 9.12 Record the following observations: 832

~) D 5236 9.16 Continue taking product while observing the head pressure. As long as the pressure does not rise, continue distillation. Addition of heat to the flask to maintain product rate should be done with great care. The final cut point must be achieved in less than 1 h after the flask temperature has risen above 310"C (590"F). Discontinue the distillation as soon as a distinct rise in pressure is noted or 90 vol % has been distilled. NOTE 8--Automatic vacuum controllers tend to mask the initial rise in pressure that indicates incipient cracking. NOTE 9--Beyond 90 vol % distilled, the flask may be too near dryness for safe operation.

DISlILLATION REPORt SUMMARY LABORATORY

OlSCml,rtOM

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9.17 When the final cut point has been achieved, the head pressure begins to rise, or 90 vol % has been distilled, discontinue all heat at once, raise the pressure slightly and allow the residue to cool while continuing to stir. 9.18 Remove the flask compensating mantle or, in the case of steel flasks, turn on air in the quench coil. 9.19 When the temperature of the residue has fallen below 150"C (302"F), remove and weigh the flask and contents to determine the mass of the residue. For larger stills, the residue can be discharged through the charging line using a positive pressure of about 10 kPa in the still. 9.20 Weigh all overhead fractions to within 0.1% of the charge mass. 9.21 Determine the relative density of all fractions and convert to 15"C (59"F) using Test Method D 1250 where applicable. 9.22 In the case of the smaller stills, recover the wettage by boiling up a small quantity of solvent such as toluene in a separate flask to wash the head and condenser. Evaporate the solvent in a hood assisted by a stream of air and weigh directly. This wettage may be treated as a separate fraction and its density estimated or blended into the residue before inspections are made. The latter must be done if the residue is to be analyzed for other than density. For larger stills, follow instructions given in Annex A6. Note that the holdup in the latter case includes both the overhead wettage and the wettage of the flask with residue and must be considered a separate fraction. Density must be measured in this case.

'rltto

OIVA

o.¢h.°#

G.~.

ke L i t e

FIG. 8(a)

Distillation Report

11.1.6 The cumulative mass and volume percentages. 11.2 The observations recorded in 9.12 during the distillation are normally included as a second sheet attached to the summary sheet. Examples of a distillation report and record are illustrated in Figs. 8(a) and 8(b). l 1.3 Plot curves of temperature in degrees Celsius AET as ordinates against the percents by mass and volume calculated for the fractions above. A smooth curve through this plot constitutes the final distillation curve.

10. Calculation 10.1 Calculate the weight recovery by adding the masses of all the fractions plus the holdup or wettage. The total must be between 99.6 % and 100.1% of the weight of the charge to be acceptable. Show the actual loss on the record, and prorate the loss among all fractions. 10.2 Calculate the volume of each fraction by dividing the mass of each fraction by its relative density.

12. Precision and Bias 12.1 Precision--The precision of this test method as determined by the statistical examination of the interlaboratory test results is as follows: 7 NOTE 10--The following precision data were developed from data obtained from a 1986 cooperative program (six samples, five laboratories), a 1988 cooperative program (three samples, four laboratories), and individual laboratory data on different samples (five samples, three laboratories). Although these data do not meet the statistical requirements of RR:D02-1007,8 due to the time and cost involved it is unlikely that an additional cooperative program will be initiated soon.

11. Report 11.1 A summary sheet for the run must include the following: 11.1.1 The mass of the charge in grams, 11.1.2 The density of the charge in grams per millilitre at 15"C to four significant figures, 11.1.3 The volume of the charge in mL at 15"C, 11.1.4 The gain or loss in mass and volume to the nearest 0.1%, 11.1.5 A listing of the fractions in order of boiling point with the residue recorded last, and

12.1.1 Repeatability--The difference between successive 7 The results of the cooperative test programs from which these values have been derived are filed at ASTM Headquarters. Request RR:D02-1288. s Annual Book of ASTM Standards, Vol 05.03.

833

~1~') D 523fi DISTILLATION RECORD IlUW NO.

vie Ob,'d

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Teg~, C~J'n

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31

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FIG. 8(b)

Distillation Record

results obtained by the same operator with the same apparatus under constant operating conditions on identical test materials would, in the long run, in the normal and correct operation of this test method exceed the following values only in one case in twenty: Liquid Volume (LV) % Distilled

Repeatability, "C

10 20 30 40 50 60 70

6.1 4.5 6.1 4.9 5.7 4.1 4.8 4.9 4.4

80

90

one case in twenty: Liquid Volume (LV) % Distilled

Reproducibility, "C

10 20 30 40 50

16.9 12.8 13.5 I 1.2 14.2

60

8.4

70

11.4 5.1 4.4

80

90

12.2 Bias--Since there is no accepted reference material suitable for determining the bias for the procedure in this test method for measuring vacuum distillation characteristics, bias has not been determined.

12.1.2 Reproducibility--The difference between two single and independent results obtained by different operators working in different laboratories on identical material would in the long run, exceed the following values only in

13. Keywords 13. l crude oils; distillation; heavy oils, potstili; residue; vacuum

834

~) D 5236

ANNEXES

(Mandatory Information) AI. T E S T M E T H O D FOR D E T E R M I N A T I O N OF T E M P E R A T U R E R E S P O N S E T I M E AI.1 Scope A 1.1.1 The test method in this annex is for the determination of temperature response time based upon the rate of cooling of the sensor under prescribed conditions.

range allowing interpolation to 0. I*C (0.2*F). Set the chart speed at 30 cm/h for readability. A1.3.3 Insert the sensor into a hole in the center of one side of a closed cardboard box about 30 cm on a side. Hold the sensor in place by a friction fit on the joint. Allow the sensor to reach equilibrium temperature. Record the temperature when it becomes stable. A1.3.4 Remove the sensor and insert it into the heated thermoweU in the beaker of water. After the sensor has reached a temperature of 70"C (158"F), remove it and immediately insert it into the hole in the box. Note with a stopwatch, or record on the strip chart, the time interval while the sensor cools from 30"C (54"F) above to 5"C (9*F) above the temperature recorded in A1.3.3. AI.3.5 A time interval in excess of 60 s is unacceptable.

A1.2 Significance and Use AI.2.1 This test method is performed to assure that the sensor is able to respond to changes in temperature fast enough that no error due to lag is introduced in a rapidly rising temperature curve. AI.2.2 The importance of this test method is greatest under vacuum conditions when the heat content of the vapors is minimal. A1.3 Procedure A 1.3.1 Arrange a I-L beaker of water on a hot plate with a glass thermowell supported vertically in the water. Maintain the temperature of the water at 80 ___5"C (175 + 9*F). AI.3.2 Connect the sensor to an instrument, preferably with a digital readout, with readability to 0.1*C. Alternatively, connect the sensor to a strip chart recorder of suitable

A1.4 Precision and Bias A 1.4.1 No statement is made concerning either the precision or bias of this annex for determining the temperature response time because the result is used to determine whether there is conformance to the stated criteria in this test method.

A2. PRACTICE FOR CALIBRATION OF SENSORS A2.1 Scope A2.1.1 The practice in this annex is for the calibration of temperature sensors with their associated reading or recording instruments, or both.

water, a Dewar flask filled with crushed ice and water can be used. A2.4.2 Alternatively, a Tensimeter, 9 as shown in Fig. A2.2, can be used to measure the boiling points of pure compounds at atmospheric pressure.

A2.2 Summary of Practice A2.2.1 The temperature sensor with its associated instrument is calibrated by observing and recording the freezing points of pure metals or the boiling points of pure compounds.

A2.5 Procedure A2.5.1 Vapor TemperatureSensors (by Melting Point): A2.5.1.1 This procedure is recommended for initial calibration and for use in cases of dispute. A2.5.1.2 Set up the melting point bath containing a suitable metal chosen from Table A2.1 and ensure that there is about 0.5 m L of suitable silicone oil in the bottom of the thermoweil. Insert the temperature sensor(s) into the well making certain that the sensing tips are touching the bottom. Connect the associated instrument(s). A2.5.1.3 Heat the melting point bath to a temperature

A2.3 Significance and Use A2.3.1 Vapor temperature measurement is one of the two major sources of error in distillation data. The sensors must be calibrated over the full range of useful temperatures at the time of first use in combination with their associated instruments and recalibrated whenever the sensor or its instrument is repaired or serviced. A2.3.2 Rechecking of the calibrations must be carded out on a routine basis as described in A2.5 because this distillation procedure is used for generating primary data fundamental to cost, yield and design practices in the petroleum industry.

9 Cooke, et al. Review of Scientific Instrument, Vol 32, 1961, p. 780.

TABLE A2.1

Primary Temperature Standards (Melting Points)

Material Tin:Lead:Cadmium (50:32:18) Tin

A2.4 Apparatus A2.4.1 A suitable apparatus for primary temperature reference is shown in Fig. A2. I. For the freezing point of

Lead

835

Temperature, °C 145.0 231.9 327.4

I~!~ MELTING

POINT

BATH

THERMOWELL

FOR TEMPERATURE

D 5236

STANDARDS

1

i

PURE GRAPHITE CRUCIBLE ;)5 mat OI) )~ 300 ram

70mmOD

FiLL TO THIS LEVEL WITH REAGENT PURITY METAL --STANDARD DEWAR FLASK

OF $mm RO0 PORT SOTTOM

Omm 1,0 S4-+ I,Dm

ASBESTOS TAPE WRAPPING TO MAKE CRUCIBLE SNUG FIT INSIOE DEWAR

li

::

ELECTRIC HEATER 100 H

O0

$ H(ATING P5%ICi'L( AT BorTol4 ONLY

LIMED HITH SIC OR SIIITER[O fdJL~$ |O - 29 14[$11 OH IlOIlOl( OMLY PR[S[RVlHG fXPOS[O .~tARP POIMIS METAL FOOT

FIG. A2.2 FIG. A2.1

Melting Point Bath for Temperature Standards

about 10*C above the melting point of the metal inside and hold at this temperature for at least 5 min to ensure that all the metal has melted. A2.5.1.4 Discontinue heating and observe and record the cooling curve. When the curve exhibits a plateau of constant temperature for longer than 1 min, the temperature of the plateau is recorded as the calibration temperature. If the freezing plateau is too short, it can be prolonged by employing some heat during the cooling cycle. However, if excessive additional heat is required to sustain the plateau, it would indicate that the melt bath has become contaminated or excessively oxidized and the metal must be replaced. A2.5.1.5 Obtain the calibration temperature at each of the points in Table A2.1 to the nearest 0.2"C (0.4*F). A2.5.1.6 Set up a table by listing the corrections to be added to the observed temperatures to give the true temperature at each of the calibration points. A plot of the corrections to be added at each observed temperature with a smooth curve between them, can be employed in routine use.

A2.5.2 Vapor Temperature Sensors (by Boiling PoinO:

836

Tensimeter

A2.5.2.1 This practice is not regarded as primary temperature reference but is acceptable for routine laboratory use. A2.5.2.2 Set up a Tensimeter9 as illustrated in Fig. A2.2 and ensure that it is clean. Charge it with 10 mL of one of the materials listed in Table A2.2. The materials for this test must be certified to be greater than 99.9 % pure. A2.5.2.3 Insert the test sensor and apply heat at a rate that will maintain active steady boiling so that the tip of the thermowell or sensor is covered with bubbling liquid. A2.5.2.4 Obtain the calibration temperature at each of the points in Table A2.2 to the nearest 0.2"C (0.4*F). A2.5.2.5 Set up a table by listing the corrections to be added to the observed temperatures to give the true temperature at each of the calibration points. A plot of the corrections to be added at each observed temperature with a smooth curve between them, can be employed in routine use. TABLE A2.2 Boiling Points at Atmospheric Pressure Matedal Temperature, oC Water 100.0 n-Heptane 98.5 Tetrahydronaphthalene 207.2 Tetradecane 252.5

~)

D 5236

A3. PRACTICE FOR T H E CALIBRATION O F PRESSURE SENSORS TO

A3.1 Scope A3.1.1 The practice in this annex is for the calibration of pressure sensing devices used for the determination of absolute pressures in the system during distillation.

STO

B TEST

GAUGFS

A3.2 Referenced Document A3.2.1 ASTM Standard." D 1160 Test Method for Distillation of Petroleum Products at Reduced Pressures 2

A3.3 Summary of Practice A3.3. I The pressure sensing instruments are calibrated by reference to a McLeod gage over the full operating range of pressures.

A3.4 Significance and Use A3.4.1 Measurement of vacuum (operating pressure) is one of the two main sources of error in the distillation procedure. It is therefore of prime importance that the instructions below be followed with great care and on a routine basis. This practice eliminates dependence on outside sources for certification and permits convenient and verifiable rechecking of electric gages in house. A3.4.2 Electric pressure measuring instruments must be checked at least once per month. Tensimeters 6 must be observed routinely to ensure that the boiling inside is crisp and clean. Any tendency to foam indicates possible contamination. In that case, clean and recharge the instrument to restore accuracy. A3.4.3 The only primary standard for the measurement of absolute pressure is the McLeod gage because it is calibrated from measurement of its dimensions. A procedure is described in Test Method D 1160. A calibrated McLeod gage covering the range 0-10 kPa and another covering the range 0 to 1 kPa are recommended to ensure that the test system is moisture free. A single gage with two calibrated volumes thus having two scales of different ranges can be used for convenience. McLeod gages must be baked out hot and empty under vacuum before use and thereafter protected from exposure to atmospheric air.

NITROGEN

FIG. A3.1 Calibrationof VacuumGages A3.5 Procedure A3.5.1 Set up clean dry apparatus as illustrated in Fig. A3.1 and connect the test sensor(s) and the reference gage to the manifold. A3.5.2 Pump the system down to a pressure of about 0.01 kPa and isolate the pump and the bleed valve. Allow the system to stabilize for at least 2 rain. A3.5.3 If the pressure rises more than 10 % in the next 2 rain the system must be checked for leaks and corrected before continuing with calibration. A3.5.4 Check the system for the presence of water vapor by noting the readings of both scales of the McLeod gage. A3.5.5 Read and record the pressures indicated on the test gage and the reference gage(s) at three or more levels over the range 0.01 to 10 kPa. A3.5.6 Record the errors if any, in the readings of the test gage and apply these corrections to all observations made with that gage in service. Some electric gages may provide for error correction, in which case, adjust the reading to eliminate the error.

A4. T E S T M E T H O D FOR DEHYDRATION O F A W E T S A M P L E OF OIL

A4.1 Scope

mass-percent of water is calculated.

A4. I. 1 The test method in this annex is for dehydrating a wet sample of oil (> 0.1% water) prior to vacuum distillation and determining the water content.

A4.3 Significance and Use A4.3.1 Dehydration is important in order to allow the subsequent distillation to proceed smoothly.

A4.2 Summary of Test Method A4.4 Apparatus

A4.2.1 A sufficient quantity of the sample is distilled under atmospheric pressure to 150"C, the hydrocarbon fraction decanted, and dry components recombined. The

A4.4.1 The dehydration of a wet sample requires apparatus such as that shown in Fig. I. Fit the distillation flask 837

It~) D 5238 with a capillary line for the passage of nitrogen into the liquid.

A4.5.8 Recombine the cooled decanted fractions with the distillation residue observing the usual precautions against losses. If the reblending is done in the original flask, this flask can be used for the subsequent distillation. Do not recombine the trap fraction. A4.5.9 Record the quantity of dry oil recovered.

A4.5 Procedure A4.5.1 Decant any bulk water that may be present. Weigh by difference to the nearest gram, the required volume of wet sample into a distillation flask containing a magnetic stirrer. A4.5.2 Attach the flask to the distillation head and pass a slow (8 cm3/s) stream of nitrogen through the capillary. Vent the condenser through a trap maintained at the temperature of dry ice ((-70"C) (-94"F)). A4.5.3 Apply heat to the flask, regulating it to attain a moderate rate. Remove distillate slowly until water ceases to distill and continue for an additional 3 to 5 % of distillate. A4.5.4 Shut off the heating system. Cool the flask and contents to below 175"C temperature. A4.5.5 Weigh the distillate fraction and residue. A4.5.6 To separate the water from the distillate fraction, cool to -5"C and decant the hydrocarbon liquid. Weigh the water. A4.5.7 Remove the condenser and rinse it with alcohol or acetone to remove adhering drops of water. Dry with air and replace it.

A4.6 Calculation A4.6.1 Calculate the mass-percent of water using Eq A4.1: 100 A W ~ - B (A4.1) where: A = mass of water recovered, g, B = mass of charge, g, W = mass-percent of water, and 100 = percentage constant. A4.7 Precision and Bias A4.7.1 No statement is made concerning either the precision or bias of this annex for mass-percent water because the test method in this annex is used for sample preparation for Test Method D 5236.

838

tl~ D 5236 A5. PRACTICE F O R C O N V E R S I O N OF O B S E R V E D V A P O R T E M P E R A T U R E S T O A T M O S P H E R I C E Q U I V A L E N T T E M P E R A T U R E (AET) D = density at 15°C. By custom, either the mid vapor temperature of the fraction or the mid-point of a gas chromatographic distillation of the fraction can be used for the mean average boiling point. In either case the method must be specified. A5.3.3.1 An estimate of the K-factor can be made using Fig. A5.1. A5.3.4 Calculate the correction to be applied to the AET using Eq A5.5:

A5.1 Scope A5.1.1 This practice is for conversion of actual distillation temperature obtained at sub-ambient pressures to atmospheric equivalent temperature (AET) corresponding to 101.3 kPa (760 m m Hg) by means of equations derived by Maxwell and Bonnell. I°:l

A5.2 Significance and Use A5.2.1 Final data on atmospheric equivalent temperatures are to be obtained by computation. Figure 7 is provided only as a guide in estimating the cut points during distillation.

t = - 1 . 4 [ K - 1 2 ] [lOg(p~)]

where: t = correction, *C, Pa = atmospheric pressure, kPa, and Po = observed pressure, kPa. A5.3.4.1 An estimate of the correction can be made using Fig. A5.2.

A5.3 Calculation A5.3.1 Convert observed vapor temperature to atmospheric equivalent temperature using Eq A5.1:

AET=

748.1 A

1 T + 273

- 273

(A5.1)

4.741

+ 0.3861 A - 0.00051606

-

log(P=bJPatm)

3.877 - log(P~,/P,,m) 2387.262 - 95.76 log(Pabs/P=tm)

600 -0,75

550

_--- 450

O0

~

I10 ~ r

g

(J

I00-

I.-."

- 0.0002867 (A5.3)

- -

-

0.80

75~

d

Z

500

6 -; q

a

I--

350 ~

--500

o

A5.3.2 The equations are correct only for fractions that have a Watson K-factor of 12.0 +_ 0.2 and boiling between 38 and 371"C. The K-factor shall be assumed to be twelve and any effect of K-factor ignored unless there is mutual agreement to the contrary. A5.3.3 If correction is required, calculate the K-factor using Eq A5.4: 341.8 (B - 273)

D

600

i400

0.0002867 (A5.2)

NOTE A5. l--Because the derivation of A is based on a pressure ratio, it is unit independent. However, P=m and Pob, must be in the same units.

K--

650

-~500

- 0.70

2876.663 - 43.00 log(Pab,/Patm) If the operating pressure > 0.266 kPa (> 2 m m Hg): A=

i

- - 0,65

where: A E T = atmospheric equivalent temperature, *C, T = observed vapor temperature, *C, and P = pressure, kPa ( m m of Hg). If the operating pressure __. 0.266 kPa (_< 2 m m Hg): A=

(A5.5)

- 200

250

50

-085

uJ cc

25

090: /

II

o

IC

:

I -

Z O 0~

200

g~=--'i5°

z

150

O0 JO

(A5.4)

where: B = mean average boiling point, *C, and

lO~J

I

I00

-- 1.00

105

,o Maxwell and Bonnell, Industrial Engineering Chemistry, Vol 49, 1957, p. 1187. ~t These equations are convenient versions of the equations published in Section 5A I. 13 of the API Technical Data Book.

i,o

50

NoTE--Reprinted from API Technical Data Book, June 1980, by permission of American Petroleum Institute. FIG. A 5 , 1

839

W a t s o n C h a r a c t e r i z a t i o n F a c t o r of P e t r o l e u m Fractions

~) o.0ool

0.001

0.1

0.01

D 5236

1

10

10

1

100

+25

100 ~25

b-20

+20

o-15

+15

P*

~10

E+10 o

.c__-

~5

+5 0 Z

o p.

0

0

-5

-5 c

o

-10

~ -10

o ¢J

-15

-15

-20

-20

-25 0.0001

-25 0.001

0.01

2

5 0.1

z

a

1

~

o

10

<

o 100

-

"

1

Pa

[

"

Observed Vapor Pressure FIG. A5.2

"

"

10

100

kPa

I

Boiling Point Corrections for K ~ F a c t o r

A6. TEST M E T H O D FOR DETERMINATION OF W E T r A G E A6.1 S c o p e A6. I. 1 The test method in this annex is for determining the amount of material that remains on the inside walls of the apparatus after a distillation is complete. It is intended for use mainly with stills having flasks too large for easy dismantling, but can also be used for smaller stills. A6.2 S u m m a r y o f T e s t M e t h o d A6.2.1 A small charge of solvent is distilled in the dirty apparatus after a run. The residue is discharged and then freed of solvent to recover the wettage. A6.3 Significance and Use A6.3.1 Distillation apparatus can retain up to 0.5 % of a charge on their inside surfaces at the end of a run. A6.3.2 Wettage includes that of the flask because the flask is not removed for separate treatment.

A6.4 Procedure A6.4.1 Charge the dirty still with a volume of toluene equal to 10 to 20 % of a normal charge. A6.4.2 Apply heat and boil the toluene until all the upper parts are well rinsed, (about 3 min), and shut down. A6.4.3 After the still has cooled, recover the liquid from flask and distill off the solvent in a hood. Elimination of the last traces can be assisted by a gentle stream of air. A6.4.4 Weigh the recovered wettage and determine its density. A6.4.5 Treat the wettage as a separate fraction. A6.5

Precision and Bias

A6.5 No statement is made concerning either the precision or bias of this annex for measuring wettage because the result is used solely within the context of Test Method D 5236.

840

(~ D 5236 The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and ff not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration st a meeting of the responsible technical committee, which you may attend, ff you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 100 Barr Harbor Drive, West Conshohockan, PA 19428.

841

(~~T~) Designation: D 5273 - 92 Standard Guide for Analysis of Propylene Concentrates I This standard is issued under the fixed designation D 5273; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (0 indicates an editorial change since the last revision or reapproval.

bustion and Chemiluminescence Detection a D4864 Test Method for Determination of Traces of Methanol in Propylene Concentrates by Gas Chromatography a

1. Scope 1.1 This guide lists the major grades ofpropylene concentrates produced in North America. It includes possible components and test methods, both ASTM and other, either actually used, or believed to be in use, to test for these properties. This guide is not intended to be used or construed as a set of specifications for any grade of propylene concentrate. 1.2 The values stated in SI units are to be regarded as the standard. 1.3 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

3. Terminology 3.1 Definitions: 3.1.1 outaging, n--practice of removing a portion of liquid contents from a conventional sampling cylinder after filling to provide expansion room. 3.1.2 propylene concentrate, n--hydrocarbon product containing more than 50 % propylene. 3.1.2.1 DiscussionmGrades of propylene concentrates listed in this guide are: polymer, 99.0 % minimum propylene content; chemical, 92.0 %; and refinery, 60 %. 3.2 Symbols: 3.2.1 AgDDC, n--silver diethyldithiocarbamate. 3.2.2 GC, n--gas chromatograph. 3.2.3 GC-AED, n--gas chromatography atomic emission detector. 3.2.4 GC-ECD, n--gas chromatography electron capture detector. 3.2.5 GC-FPD, n--gas chromatography flame photometric detector. 3.2.6 GC.PID, n--gas chromatography photoionization detector. 3.2.7 GC-SCD, n--gas chromatography sulfur chemiluminescent detector. 3.2.8 IC, n--ion chromatography. 3.2.9 ICP-MS, n--inductively coupled plasma-mass spectrometry. 3.2.10 LPG or LP gases, n--liquified petroleum gas.

2. Referenced Documents 2.1 ASTM Standards: D 2163 Test Method for Analysis of Liquefied Petroleum (LP) Gases and Propene Concentrates by Gas Chromatography 2 D 2384 Test Methods for Traces of Volatile Chlorides in Butane-Butene Mixtures 2 D 2504 Test Method for Noncondensable Gases in C2 and Lighter Hydrocarbon Products by Gas Chromatography 2 D 2505 Test Method for Ethylene, Other Hydrocarbons, and Carbon Dioxide in High-Purity Ethylene by Gas Chromatography 2 D 2712 Test Method for Hydrocarbon Traces in Propylene Concentrates by Gas Chromatography 2 D 3227 Test Method for Mercaptan Sulfur in Gasoline, Kerosine, Aviation Turbine, and Distillate Fuels (Potentiometric Method) 2 D3246 Test Method for Sulfur in Petroleum Gas by Oxidative Microcoulometry2 D 3700 Practice for Containing Hydrocarbon Fluid Samples Using a Floating Piston Cylinder 3 D 4178 Practice for Calibrating Moisture Analyzers 3 D 4468 Test Method for Total Sulfur in Gaseous Fuels by Hydrogenolysis and Rateometric Colorimetry4 D 4629 Test Method for Trace Nitrogen in Liquid Petroleum Hydrocarbons by Syringe/Inlet Oxidative Com-

4. Significance and Use 4.1 This guide is intended to provide information on the likely composition of propylene concentrates and on probable ways to test them. Since there are currently no ASTM test methods for determining all components of interest, this guide provides information on other potentially available test methods. 4.2 Although this guide is not to be used for specifications, it can provide a starting point for parties to develop mutually agreed upon specifications which meet their respective requirements. It can also be used as a starting point in finding suitable test methods for determining various components of propylene.

J This guide is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.D0.02 on C.~ Test Methods. Current edition approved Aug. 15, 1992. Published October 1992. 2 Annual Book of ASTM Standards, Vol 05.02. 3 Annual Book of ASTM Standards, Vol 05.03. 4 Annual Book of ASTM Standards, Vol 05.05.

5. Sampling 5.1 General--Sample propylene concentrates are to be analyzed for trace components by a technique that minimizes or eliminates losses of light components and concen842

~ TABLE 1

D 5273

Possible Composition of Propylene Concentrate,=

Component

Polymer Grade

Chemical Grade

Refinery Grade

Test Method

Propylene, ~ mass Propane, ~ mass Methane, mg/kg Ethane, mg/kg Acetylene, mg/kg Ethylene, mg/kg Cyclopropane, mg/kg Methylacetylene, mg/kg Propadlene, mg/kg Butenes, mg/kg Butanes, mg/kg 1,3 butadiene, mg/kg C5s, mg/kg C6s, and heavier, mg/kg Benzene, mg/kg Ha, mg/kg Oa, rng/kg CO, mg/kg CO=, mg/kg N2, mg/kg HaS, mg/kg CoS, mg/kg Total S, mg/kg Mercaptan, S, mg/kg Water, mg/kg Total nitrogen, mg/kg Total chloride, mg/kg Methanol, mg/kg O~er alcohols, mg/kg Total oxygenates, mg/kg Arsine, mg/kg Total hydrides, mg/kg

99.0+ 0.1 to 1.0 <2 to 100 <2 to 200 <1 to 10 <2 to 100 <1 to 10 <1 to 10 <1 to 10 <1 to 20 <2 to 50 <1 to 10 <1 to 10 <1 to 10 <0.1 to 10 <1 to 10 <1 to 10 <1 to 10 <1 to 10 <2 to 40 <0.1 to 10 <1 to 10 <1 to 10 <1 to 5 <1 to 25 <1 to 5 <1 to 5 <1 to 5 <1 to 5 <1 to 5 <0.1 to 1 <0.1 to 1

92 to 99 1 to 8 <10 to 1000 <10 to 2000 <2 to 100 <2 to 100 <2 to 500 <2 to 100 <2 to 100 <2 to 200 <10 to 1000 <2 to 50 <2 to 100 <2 to 100 <0.1 to 10 <2 to 100 <2 to 100 <2 to 100 <2 to 100 <10 to 1000 <1 to 20 <1 to 10 <1 to 10 <1 to 10 <2 to 100 <1 to 10 <1 to 10 <1 tO 10 <1 to 10 <1 to 10 <0.1 to 1 <0.1 to 1

60 to 90 10 to 35 <10 to 1000 <100 to 100 000

D 2163 D 2163 See Table 2 See Table 2 D 2712 D 2712 See Table 2 D 2712 D 2712 D 2712 See Table 2 D 2712 See Table 2 See Table 2 See Table 2 See Table 2 See Table 2 See Table 2 See Table 2 See Table 2 See Table 2 See Table 2 See Table 2 See Table 2 See Table 2 See Table 2 See Table 2 D 4864 See Table 2 See Table 2 See Table 2 See Table 2

<50 tO 5000 <2 to 500 <10 to 1000 <10 to 1000 <100 to 10 000 <100 to 15 000 <2 to 100 <2 to 100 <2 to 100 ... ... ... <'2' to 100 ... <1' to 50 <10 to 250 <1 to 10 <2 to 100 ... ... ... .,. <().1 to 1 <0.1 to 1

loss of heavier components, if present, and concentration of lighter ones. Test Method D 2712 describes a low pressure vaporization sampling technique that is suitable to determine trace compounds through butadiene. 5.5 Reactive and Polar Components: 5.5.1 Determination of reactive components, such as certain sulfur compounds and arsine, is generally believed to require special sample containers, such as TFE-fluorocarbon lined cylinders, or containers that have been specially passivated. 5.5.2 It is very difficult to obtain a valid sample to determine traces of polar compounds, such as water and ammonia, in the lab. On-line analyzers, if available, or sorption of the analyte at the sample source for subsequent lab analysis, are believed to yield the most accurate results.

tration of heavy ones. The sections below list some different sampling methods and principles. However, it is not the intent of this guide to list procedures that are applicable to all sampling situations. It is strongly recommended that samples be obtained under the supervision of a person with wide knowledge and experience in sampling olefinic liquified petroleum gases. Also, even though this guide does not address the location of a sampling point in a line or vessel, the importance of the proper sampling location cannot be over-emphasized. 5.2 FloatingPiston CylinderRTest Method D 3700 meets the criterion of minimizing or eliminating loss of light compounds and concentration of heavy ones. However, some labs have safety codes preventing use of rupture-disc piston containers. Alternative procedures must be used in these labs. 5.3 Conventional Outaging MethodbThe widely used outaging technique (that is, the practice of removing a portion of the fluid contents from a conventional sampling cylinder after filling in order to provide expansion room) causes a loss of light components into the vapor space. Subsequent handling to recapture these light ends in the liquid phases of the sample, such as repressurization of the cylinder contents with an inert gas, will not completely effect their recovery, especially the permanent gases. However, the loss is not significant to some users. 5.4 Vaporization Methods--Vaporization of the sample, either at the source or in the lab prior to analysis, can cause

6. Composition and Test Methods 6.1 Table l indicates possible composition ranges and ASTM test methods for different grades of propylene concentrates. Table 2 lists other test methods known or believed to be in use. 6.2 Listing of any given component in Table 1 does not mean that the component will be present in all, or even any, propylene products. Inclusion in the list is definitely not a recommendation that all propylene products should be tested for the component.

7. Keywords 7.1 propylene; propylene product concentrations; propylene test methods

843

~ TABLE 2

D 5273

Propylene Test M e t h o d s (Non-ASTM)

Components Methane, ethane, cyclopropane, butanes, and C5s C6s and heavier Benzene H=, N2, O2, CO CO2 Carbonyl sulfide Hydrogen sulfide Total sulfur Mercaptan sulfur Water Total nitrogen (bound) Total chlorides Amine

Total hydrides Ammonia

Other oxygenates Other alcohols

Possible Test Methods An adaptation of Test Method D 2712 is used by some labs. Others use a GC wide-bore capillary method. GC wide-bore capillary or packed high temperature columns, or both, are used by some. Capillary or pecked column GC methods. An adaptation of Test Method D 2504 is used by some. An adaptation of Test Method D 2505 is used by some. A GC-FPD method is currently undergoing ASTM cooperative testing. Other methods used in the industry are GC-PID, GC-conductivity, GC-SCD, UOP-212, and GC in series with a Test Method D 4468-type analyzer. Same as listed above for COS, except there ere no methods currently undergoing ASTM testing. Some labs use an adaptation of Test Method D 3246; others use Test Method D 4468 with an oxy-hydrogen pyrolyzer. Some methods used are: UOP 212; GC-FPD; caustic absorption/potentiometric titration analysis by Test Method D 3227. Obtaining a valid sample for lab analysis is extremely difficult. Instead of a lab method, an ASTM study group developed in 1982 a standard practice for calibrating moisture analyzers, Practice O 4178. Several types of portable and on-line analyzers are available. An adaptation of Test Method D 4629 is used by some labs; others use microcoulometry. An adaptation of Test Methods D 2384 may be used by some labs; others use reductive microcoulometry. Some methods known to be in use are: AgDDC absorption/colodmetdc finish AgDDC absorption/GFAAS finish direct GC-ECD method direct GC-PID method MDA scientific toxic gas analyzer Some methods in use are: acid absorption/Nesslar finish acid absorption/specific ion electrode acid absorption/IC finish MDA tape method GC methods; GC-AED, colodmetdc methods GC methods, both capillary and packed column. Variation of Test Method D 4864

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical commlUea and must be reviewed every five years and ff not revised, either reappreved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addreased to ASTM Headquarters. Your comments will receive careful conaldaration at a meeting of the responsible technical committee, which you may attend, ff you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103,

844

~l~

Designation: D 5274 - 92 Standard Guide for Analysis of 1,3-Butadiene Product 1 This standard is issued under the fixed designation D 5274; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (¢) indicates an editorial change since the last revision or reapproval.

bustion and Chemiluminescence Detection* D4864 Test Method for Determination of Traces of Methanol in Propylene Concentrates by Gas Chromatography5

1. Scope 1.1 This guide covers the analysis of 1,3-butadiene products produced in North America. It includes possible components and test methods, both ASTM and other, either actually used or believed to be in use, to test for these components. This guide is not intended to be used or construed as a set of specifications for butadiene products. 1.2 The values given in SI units are to be regarded as the standard. The inch-pound units given in parentheses are for information only. 1.3 This standard does not purport to address all of the

3. Terminology 3.1 Definition: 3.1.1 1,3-butadiene--hydrocarbon

safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

product containing more than 99 % 1,3-butadiene. 3.2 Symbols." 3.2.1 BHT--butyl hydroxy toluene. 3.2.2 GC----gas chromatography. 3.2.3 pTBCwparatertiary butyl catechol. 3.2.4 4VCH-l--4-vinyi cyclo hexene ( 1,3-butadiene dimer).

2. Referenced Documents

4. Significance and Use 4.1 This guide is intended to provide information on the possible composition of 1,3-butadiene products and possible ways to test them. Since there are currently not enough ASTM standards for determining all components of interest, this guide provides information on other potentially available test methods. 4.2 Although this guide is not to be used for specifications, it can provide a starting point for parties to develop mutually agreed-upon specifications that meet their respective requirements. It can also be used as a starting point in finding suitable test methods for 1,3-butadiene components.

2.1 A S T M Standards: D 1022 Test Method for Peroxide Content of Light Hydrocarbons2 D 1025 Test Method for Nonvolatile Residue of Polymerization Grade Butadiene3 D 1157 Test Method for Total Inhibitor Content (TBC) of Light Hydrocarbons3 D 1550 ASTM Butadiene Measurement Tables 3 D 2384 Test Methods for Traces of Volatile Chlorides in Butane-Butene Mixtures4 D 2426 Test Method for Butadiene Dimer and Styrene in Butadiene Concentrates by Gas Chromatography4 D2593 Test Method for Butadiene Purity and Hydrocarbon Impurities by Gas Chromatography4 D3246 Test Method for Sulfur in Petroleum Gas by Oxidative Microcoulometry4 D 3700 Practice for Containing Hydrocarbon Fluid Samples Using a Floating Piston Cylinder5 D 4178 Practice for Calibrating Moisture Analyzers 5 D 4423 Test Method for Determination of Carbonyls in Ca Hydrocarbons5 D 4468 Test Method for Total Sulfur in Gaseous Fuels by Hydrogenolysis and Rateometric Colorimetry6 D 4629 Test Method for Trace Nitrogen in Liquid Petroleum Hydrocarbons by Syringe/Inlet Oxidative Com-

5. Sampling 5.1 Generak 5.1.1 1,3-butadiene is a very reactive hydrocarbon. It reacts with oxygen to form peroxides and to polymerize. It also dimerizes at a rate that is temperature dependent. Below 10*C (50*F), the dimerization rate is less than I mg/kg by mass/h; but, at 20"C (77"F), it increases to 3 to 4 mg/kg mass/h; and at 40"C (104*F), to 14 to 20 mg/kg mass/h. 1,3-butadiene is also classified as toxic and as a potential health hazard, having been found carcinogenic to laboratory animals. Therefore, sampling of 1,3-butadiene must adhere to the following three principles: 5. I. I. l Minimize personnel exposure. See the appropriate OSHA Material Safety Data Sheet for guidance, 5.1.1.2 Eliminate or keep to an absolute minimum the inclusion of oxygen during and after sampling, and 5.1.1.3 Sample the product at as low a temperature as possible, maintain the sample at a low temperature, and analyze it as soon as possible. Do not allow it to sit outdoors in the sun after sampling. 5.1.2 In addition to 5.l.l.l through 5.1.1.3, 1,3-butadiene to be analyzed for trace components should be sampled by a

This guide is under the jurisdiction of ASTM Committee 1)-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.D0.03 on C4 Test Methods. Current edition approved Aug. 15, 1992. Published October 1992. 2 Discontinued; see 1982 Annual Brusk of ASTM Standards, Vol 05.01. 3 Annual Book o~ ASTM Standards, Vol 05.01. 4 Annual Book ofASTM Standard~', Vol 05.02. 5 Annual Book of ASTM Standards, Vol 05.03. 6 ..I/mual Book ofASTM Standard~', Vol 05.05.

845

(~ D 5274 TABLE 1 Property

1,3-Butadiene Test M e t h o d s Units

Test Method

(ASTM)

mg/kg mg/kg mg/kg mg/kg mg/kg

See Table 2 See Table 2 See Table 2 D 2593 D 2426

<1 to 25 <1 to 25 <0.1 to 10 <1 to 100 <100 to 200

mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg

<1 to <1 to <1 to <1 to <:1 to <1 to

Methanol and other alcohols Moisture

mg/kg

Nonvolatile residue Oxygen in vapor space Peroxides Propadiene Propane Propylene Purity of 1,3-butadiene Relative density Toluene Total acetylenes Total nitrogen Total sulfur

mass ~ mass ~0 mg/kg mg/kg mg/kg rng/kg mass ~, 15.6/15.6 mg/kg mg/kg mg/kg mg/kg

D 2593 See Table 2 D 4423 See Table 2 See Table 2 D 1157 See Table 2 D 4864 See Table 2 D 4178 See Table 2 D 1025 See Table 2 See Table 2 D 2593 D 2593 D 2593 D 2593 D 1550 See Table 2 D 2593 See Table 2 See Table 2

1,3-Butadiene Test Methods (Non-ASTM Methods)A

Property

Concentration Range

Amines Ammonia Benzene 1,2-butadiene 1,3-butadiene dimer (4VCH-1) C5 hydrocarbons Ca+ hydrocarbons Carbonyls Chlorides Ethylene glycol Inhibitor (p-TBC)

mg/kg

TABLE 2 Amines Ammonia Benzene Chlorides Ethylene glycol Inhibitor (BHT) Inhibitor (pTBC)

1000 1000 100 25 100 500

Methanol and other alcohols Moisture

<1 to 25 Oxygen <1 to saturated Peroxides <:0.001 to 0.2 <0.001 to 0.3 <1 to 25 <1 to 25 <1 to 25 <1 to 25 99.0 rain 0.625 to 0.630 <1 to 500 <1 to 100 <1 to 25 <1 to 25

Toluene Total sulfur Total nitrogen

Possible Test Method AdapUon of Test Method D 4629 Acid absorption with Nessler finish Acid absorption with specific ion finish CapSary gas chromatography Organic chlorides by GC, with hall detector; also, Test Methods D 2384 CapSary gas chromatography Capillary gas chromatography or titraUon method Test Method Dl157; also, gas chromatography and titration methods using cenc ammontum sulfate Adaption of Test Method O 4864 Panametrics moisture instrument; adaption of Karl Fisher titration Adaption of Panometric or Teledyne oxygen analyzers Test Method D 1022 has been discontinued; a new ASTM method using sodium thiosulfate titration IS being evaluated. Capillary gas chromatography Adaption of Test Methods D 3246 or D 4468 Adaption of Test Method D 4629; also, microcoulometry

'* The above are possible butadiene test methods or techniques which ere believed to be in use in the industry for testing. Inclusion of any test method in this list is not to be construed as a recommendation by ASTM for its use. Some of the test methods in this list are ASTM test methods that are specified for other products but ere being used by some labs for butediene analysis. However, use of ASTM test methods beyond their scope is not recommended by ASTM Precision and bias may be adversely affected.

technique that minimizes or eliminates loss of light components and concentration of heavy ones. The subsections below list some different sampling methods and principles. However, it is not the intent of this guide to list procedures that are applicable to all sampling situations. It is strongly recommended that samples be obtained under the supervision of a person with wide knowledge and experience in sampling 1,3-butadiene. 5.1.3 Also, even though this guide does not address the location of a sampling point in a line or vessel, the importance of the proper sampling location cannot be overemphasized. 5.2 Floating Piston Cylinder--Test Method D3700 meets the criterion of minimizing or elimination of loss of light components and concentration of heavy ones. However, some labs have safety codes preventing use of rupturedisc piston containers. Alternative procedures must be used in these labs. 5.3 Conventional "Outaging" Method--The widely used "outaging" techniques (that is, the practice of removing a portion of the fluid contents from a conventional sampling cylinder after filling in order to provide expansion room) causes a partial loss of light components into the vapor space. Subsequent handling to recapture these light ends in the liquid phase ofthe sample, such as repressurization of the

cylinder contents with an inert gas, is usually successful, since 1,3-butadiene seldom contains noncondensables. However, if permanent gases are present and are to be determined, an alternate procedure may be required. 5.4 Vaporization Methods--Vaporization of the sample, either at the source or in the lab prior to analysis, may cause loss of heavier components, if present, and concentration of lighter ones. Also, since 1,3-butadiene is so reactive, the heat required to vaporize may cause undesirable changes in the composition of the sample. For these reasons, vaporization is not recommended for 1,3-butadiene. 5.5 Reactive Components--Determination of reactive components, such as certain sulfur compounds, is generally believed to require special sample containers, such as TFEfluorocarbon-lined cylinders. 6. Composition ahd Test Methods 6.1 Table 1 indicates possible composition ranges and ASTM methods for 1,3-butadiene product. Table 2 lists other test methods known or believed to be in use. 7. Keywords 7.1 1,3-butadiene; 1,3-butadiene product; 1,3-butadiene test methods

The American Society for Testing and Materials takes no posit/on respecting the validity of any patent rights asserted in connection w#h any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of Infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and ff not revised, either reepproved or withdrawn. Your comments are Invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103.

846

~l~

Designation: D 5287 - 92 Standard Practice for Automatic Sampling of Gaseous Fuels 1 This standard is issued under the fixed designation D 5287; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (E) indicates an editorial change since the last revision or reapproval.

ANSI/API 2530 (AGA Report Number 3) Orifice Metering of Natural Gas and Other Related Hydrocarbon Fluids4 GPA Standard 2166 Methods of Obtaining Natural Gas Samples for Analysis by Gas Chromatography 5 NACE Standard MR-01-75 Standard Material Requirements. Sulfide Stress Cracking Resistant-Metallic Materials for Oilfield Equipment 6 2.3 Federal Documents: Code of Federal Regulations, Title 49, 173, 34(e), p. 3897

1, Scope 1.1 This practice covers the collection of natural gases and their synthetic equivalents using an automatic sampler. 1.2 This practice applies only to single-phase gas mixtures that vary in composition. A representative sample cannot be obtained from a two-phase stream. 1.3 This practice includes the selection, installation, and maintenance of automatic sampling systems. 1.4 This practice does not include the actual analysis of the acquired sample. Other applicable ASTM standards, such as Test Method D 1945, should be referenced to acquire that information. 1.5 The selection of the sampling system is dependent on several interrelated factors. These factors include source dynamics, operating conditions, cleanliness of the source gases, potential presence of moisture and hydrocarbon liquids, and trace hazardous components. For clean, dry gas sources, steady source dynamics, and normal operating conditions, the system can be very simple. As the source dynamics become more complex and the potential for liquids increases, or trace hazardous components become present, the complexity of the system selected and its controlling logic must be increased. Similarly, installation, operation, and maintenance procedures must take these dynamics into account. 1.6 The values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are for information only. 1.7 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

3. Terminology 3.1 Description of Terms Specific to This Standard." 3.1.1 automatic sampler--(see Fig. l(a) and (b)) a mechanical system, composed of a sample probe, product loop, sample extractor, sample vessel, and the necessary logic circuits to control the system throughout a period of time, the purpose of which is to compile representative samples in such a way that the final collection is representative of the composition of the gas stream. 3.1.2 representative sampleua volume of gas that has been obtained in such a way that the composition of this volume is the same as the composition of the gas stream from which it was taken. 3.1.3 retrograde condensation--the formation of liquid phase by pressure drop at constant temperature on a dew-point gas stream. 8 3.1.4 sample extractor--a device to remove the sample from the product loop and put it into the sample vessel. 3.1.5 sample loop---the valve, tubing, or manifold(s), or combination thereof, used for conducting the gas stream from the probe to the sampling device and back to the source pipe (or atmosphere). 3.1.6 sample probemthat portion of the product loop attached to and extending into the pipe containing the gas to be sampled. 3.1.7 sample vesselmthe container in which the sample is collected, stored, and transported to the analytical equipment. 3.1.8 source dynamics--changes in gas supplies, operating pressures, temperatures, flow rate, and other factors that may affect composition or state, or both.

2. Referenced Documents 2.1 ASTM Standards: D 1945 Test Method for Analysis of Natural Gas by Gas Chromatography 2 2.2 Other Standards: AGA Report Number 7 Measurement of Gas by Turbine Meters 3

4 Available from the American National Standards Institute, 11 West 42nd St., 13th Floor, New York, NY 10036. 5 Available from Gas Processors Assn, 6526 East 60th St., Tulsa, OK 74145. ~Available from National Association of Corrosion Engineers, P.O. Box 218340, Houston, TX 77218. 7 Available from Superintendent of Documents, Government Printing Office, Washington, DC 20402. s Bergman, D. F., TeL M. R., and Katz, D. L., Retrograde Condensation in Natural Gas Pipelines, American Gas Association, Arlington, VA, 1975.

i This practice is under the jurisdiction of ASTM Committee I)-3 on Gaseous Fuels and is the direct responsibility of Subcommittee 1)03.01 and Collection and Measurement of Gaseous Samples. Current edition approved Sept. 15, 1992. Published March 1993. 2 Annual Book of ASTM Standards, Vol 05.05. a Available from American Gas Association, 8501 Pleasant Valley Road, Cleveland, OH 4413 I.

847

~) D 5287 CONTROLLER ............

CONTROLLER

FLOW

q r...........

OR

TIMER

FLOW :[[[[SIGNAL OR TIMER

I I SAMPLE EXTRACTOR

SAMPLE EXTRACTOR

r--1 GAS RETURN

i

L~

r--1!

SAMPLEDISCHARGE

IL,

GAS RETURN

L

INDICATOR

VESSEL (FIXED VOLUME) PRECHARGE SIDE

SAMPLEVESSEL (FREE-FLOATING PISTON)

PRODUCT SIDE

GAS SUPPLY SAMPLE LOOP

S

GAS SUPPLY

f SAMPLE LOOP ~T~ ~

SAMPLE

~

PROBE

(e) Free-FloatingPiston Vessel

(b) Fixed Volume Vessel FIG. 1 ContinuousComposite Samplers

4. Significance and Use

port Number 3, Figs. 4 through 8 and AGA Report Number 7, Fig. 2.) 6.4 The sample probe should be constructed of stainless steel. 6.5 The sample probe should be a minimum of 5 pipe diameters from any device that could cause aerosols or significant pressure drop.

4.1 This practice should be used when and where a representative sample is required. A representative sample is necessary for accurate billing in custody transfer transactions. 4.2 This practice is not intended to preempt existing contract agreements. 4.3 Principles pertinent to this practice may be applied in most contractual agreements.

7. Sample Loop (see Fig. 4) 7.1 All valves should be straight bore, full opening, stainless steel valves. 7.2 The product loop should be I/4 in. (6.25 mm) outside diameter stainless steel tubing. 7.3 The supply line shall slope from the probe up to the sampler. All traps caused by low points shall be avoided. 7.4 The return line should slope down from the sampler to a connection of lower pressure on the pipeline. 7.5 The supply line should be as short as possible, with a minimum number of bends. 7.6 The sample loop should be insulated or heat traced, or both, if ambient temperature conditions could cause condensation of the gas flowing through the loop. 7.7 Filters or strainers that could cause the sample to be biased are not allowed in the product loop. 7.8 Flow through the sample loop should be verified.

5. Material Selection 5.1 The sampling system should be constructed of materials that will not corrode due to ambient conditions. 5.2 The selected material should be inert to all expected components of the gas stream. 5.3 If sour gas (gas that contains hydrogen sulfide and carbon dioxide) is suspected, NACE standard MR-01-75 should be adhered to.

6. Sample Probe (see Figs. 2 and 3) 6.1 The sample probe should be mounted vertically in a horizontal run. 6.2 The sample probe should penetrate into the center one-third of the pipeline. 6.3 The sample probe should not be located within the defined meter-tube region. (See ANSI/API 2530- AGA Re-

8. Automatic Sampler (see Fig. l(a) and (b)) 8.1 Installation--The sampler shall be mounted higher 848

@ CONVENTIONAL PROBE

PITOT STYLE PROBE

o

s=sz both of which are in the shape of a cylinder:

9.1.1 Variable Volume--Constant Pressure (see Fig. l(a))--These cylinders are commonly manufactured as freefloating piston configurations. Pipeline pressure communicates with one side of this piston. The sampler communicates with the other side. The sampler pumps the gas into the product side of the vessel and moves the piston, thus displacing the precharge gas back into the pipeline. The sample gas stays at or near pipeline pressure during the entire

sample period. PROBE TIP CUT HORIZONTAL TO CENTERLINE (TYP.)

CENTER I / 3

FIG. 2 Acceptable Probe Types and Installations than the sample probe. It should be as close to the sample probe as conditions allow. Manufacturer's specific instructions should be referenced. 8.2 Maintenance--The sampler should be designed for easy field maintenance. A preventative maintenance schedule as outlined by the manufacturer should be followed. 8.3 Verification--The sampling personnel should be able to verify that the sample vessel was filled as planned. This can be accomplished by several methods. 8.3.1 Chard Recorders(see Fig. 5) This should.be connected to the sample vessel to indicate and record the increase in pressure as the sample extractor adds increments to the sample vessel. This only applies to the fixed volume vessels. 8.3.2 Verification of Sample Extractor's Output-Numerous devices are available to check the output of the sample pump. The device's output may be a contact closure, a 4 to 20 mA signal, a power pulse, or any other type that can be recorded. This applies to all vessel types. 8.3.3 Pressure Transducer--Like the chart recorder, the pressure transducer measures the increasing pressure within the fixed volume vessel. 8.3.4 Calculation Method--When a free-floating pistontype vessel is properly installed with full pipeline pressure on the precharge side, the only way product can move the piston is by way of the sample extractor. If the frequency and displacement are known, the piston's position is verification of proper fill (calculated flow from the sample extractor should equal shown displacement in the free-floating piston vessel). Compensate for changes in pipeline pressure. 8.4 Control Methods--(see Fig. l(a) and (b)) Two methods of controlling samplers are currently recognized: 8.4.1 Proportional-to-Flow Control--This method paces the sampler with respect to flow. The controller shall be capable of tracking the pipeline's flow rate accurately. This method should be used when the variance of flow rates is significant. 8.4.2 Time-Based Control--This method paces the sample with respect to time only. Take care to avoid sampling from a stagnant source. The use of differential pressure switches and other similar devices may be used to stop the sampling process.

9.1.2 Constant Volume--Variable Pressure (see Fig. l(b))--These cylinders are commonly referred to as spun bottom single cavity vessels. Impact extrusion vessels also fit within this category. A connection on each end should be provided to allow for proper purge procedures. The pressure gradually builds as the sampler puts the gas into the sample vessel. 9.2 Vessel Selection--Several factors shall be considered in selecting a vessel, including phase changes, pressure, and volumes required by various test methods. 9.2.1 The variable-volume vessel and volumes required to obtain a representative composite sample should be used when the phase envelope indicates the possibility of retrograde condensation, s 9.2.2 The constant-volume vessel may be used when condensation is not a consideration. 9.2.3 One atmosphere (98 kPa) of sample gas is normally in the sample vessel at the start of the sampling cycle. In order to reduce the impact of that initial volume, at least ten additional volumes should be collected in the sample period. If the composition of the initial volume is known and can be mathematically extracted from the sample analysis, this would not apply. A METERTUBES

~

B

:

FLOW

_~ ~//////////////////////////////'//'y#~/'//d+'//~''~///~'. , ' " "I~_~ OFF LIMITS FOR SAMPLER PROBES

F .-1 OFF LIMITS FOR SAMPLE PROBES

~-

METER TUBE

r---1 F ,:--TO1

/ " ~///////A

..~"

9. Sample Vessels 9.1 Types--There are currently two recognized types,

[////////////////'////.////I.I

/ ORIFICEJ ~ /'---OPTIMUMSAMPLERPROSELOCATIONS ---'~ FIG. 3

849

p ' / / / / / / J ~,

Probe Locations

"~"

(~) D 5287 DISCHARGETO ATMOSPHERE (OPTIONAL) --~

DISCHARGETO ATMOSPHERE (OPTIONAL) --m

I

/

SAMPLE ] EXTRACTOR

i

9.4.2.1 Method for Fixed- Volume Vessels: (1) Evacuate the sample gas. (2) Connect the sample cylinder to a solvent source and a solvent return. (3) Open all valves. (4) Fill the cylinder from bottom to top with solvent. (5) Flush solvent through the cylinder for a minimum of 3 rain (longer if needed). (6) Drain the cylinder. (7) Purge the cylinder with dry, inert gas, or natural gas. (8) Close the valves. (9) Remove the cylinder from the manifold. Label and store as needed. 9.4.2.2 Alternative Method for Fixed.Volume Vessels-The method outlined in 9.4.2.1 can be utilized with the exception of steam being substituted for the solvent. The steam should be pushed by an inert gas such as nitrogen. 9.4.2.3 Method for Free-Floating Piston Vessels--The following conditions should be met: (1) The solvent source should be pressurized to 8 to 10 psig (55 to 69 kPa). (2) The solvent source should be plumbed to allow bidirectional flow. (3) This source should be connected to the valve on the product side of the free-floating piston vessel. (4) An inert gas source should be available at a pressure of approximately 15 to 20 psig (103 to 138 kPa).

DISCHARGETO ATMOSPHERE--] I SAMPLE ] I EXTRACTOR I [

\ LOWER PRESSURI

~EHS~SRU RE

S

SAMPLE PROBE

J I

AUXILIARY ORIFICE PLATE OR SIMILAR

-

DEVICE

FIG. 4

Schematicsof Acceptable Sample Loops

9.3 VesselInstallation--All vessels should be installed in a manner that will minimize dead space between the sample extractor and the vessel. 9.3.1 Variable-volume vessels should be connected so that the precharge side communicates with line pressure and can be displaced without contaminating the sample. The product side should be connected with minimum dead volume (see Fig. l(a)). Purge the sample lines with sample gas after connection of the variable-volume vessel. 9.3.2 Constant-volume vessels (see Fig. l(b)) should be in the vertical position when purging. After connecting the constant-volume vessel to the sampling device, the system shall be adequately purged with sample gas to displace any gas in the system. (See GPA Standard 2166 for further explanation of these techniques.) 9.3.3 Constant-volume vessels shall be insulated if the ambient temperature can affect the sample fill rate. Failure to do this will render the sample useless. 9.3.4 Only one sample vessel at a time is allowed to be connected to the sample extractor. 9.4 Cleaning--All vessels should be free of contaminants from previous samples before they are reinstalled on the sampler. If, however, the remaining contents are known and are accounted for, they are not considered contaminants. 9.4.1 CleaningSolvents--A solvent should be chosen that will meet the following requirements: 9.4.1.1 Dissolves all constituents of the gas stream, 9.4.1.2 Has a low enough boiling point to vaporize, leaving no measurable residue (measurable by the means used to analyze the natural gas sample), 9.4.1.3 Does not react with the seals found in the valves or free-floating piston vessels, and 9.4.1.4 Gives a characteristic chromatographic peak that does not interfere with the hydrocarbon peaks of interest. 9.4.2 Cleaning Methods--The list below of methods are for reference only. There are many other acceptable methods.

CHARTRECORDER .(TYP VERIFICATIONMETHOD)

I L CHART INDICATING A GOOD FILL

SAMPLER

I/8"TUBING MAX. SAMPLE EXTRACTOR

II

FIXED VOLUME VESSEL (TYP INSTALLATION)

L-~ FIG. 5

850

ChartRecorder

o 52e7 (5) The inert gas source should be plumbed as to allow bidirectional flow. (6) The inert gas supply is to be connected to the precharge side of the vessel. (7) The inert pressure switching valve is to be toggled, to allow the piston to evacuate the cylinder and then allow the vessel to fill with solvent. (8) Purge the vessel and fill with solvent at least three times. (9) Purge the vessel with an inert gas source, seal, and store. 9.5 Lubrication of Free-Floating Piston VesselsmThe lubricant on the floating piston moving parts should be as light as possible. No components of the gas to be sampled can be soluble in the lubricant. 9 9.6 Leak Inspection--All vessels should be free of leaks. 9.6.1 Fixed-Volume Vessels: 9.6.1.2 Leak TestmPressurize the cylinder only using an inert gas source. Do not exceed the vessel's maximum rated working pressure or that of the relief device. Helium is extremely reliable. Its ability to reveal small leaks surpasses

most of the commonly used inert gases. The vessel shall be free of any observable leaks when immersed in water. 9.6.2 Free-Floating Piston Vessels: 9.6.2. I Visual lnspection--A visual inspection should be made to check for obvious mechanical defects. 9.6.2.2 Leak Test: (1) Pressurize the cylinder to 1000 psig (6.9 MPa) or near the maximum allowed by the installed relief device, using an inert gas source on one side only. Bubble test the valves and piston seals. (2) Depressurize and pressurize the other side. Bubble test the valves and piston seals. 9.6.3 Mark the cylinders as inspected. Seal and store for reinstallation. 9.7 Department of TransportationmA periodic retesting or reinspection of 3E specified cylinders is not currently required by the Department of Transportation (DOT). This also applies to DOT-E vessels manufactured under DOT-3E compliance (free-floating piston vessels marked as such). Reference Code of Federal Regulations, Title 49, 173, 34(e), page 389, for additional and further information. The manufacturer's DOT exemption papers should also be referenced. Other types of cylinders may require periodic requalification.

9 Krytox AC and AD, manufactured by DuPont Co., Chemicals & Pigments Dept., 1007 Market St., Wilmington, DE 19898, have been found satisfactory for this purpose.

10. Keyword 10.1 gaseous fuels

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reapproved or withdrawn. Your comments are invited either for revision Of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103.

851

(~~1~) Designation:D 5291 - 96 Standard Test Methods for Instrumental Determination of Carbon, Hydrogen, and Nitrogen in Petroleum Products and Lubricants 1 This standard is issued under the fixed designation D 5291; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (~) indicates an editorial change since the last revision or reapproval.

3. Summary of Test Methods 3.1 In these test methods, carbon, hydrogen, and nitrogen are determined concurrently in a single instrumental procedure. With some systems, the procedure consists of simply weighing a portion of the sample, placing the portion in the instrument, and initiating the (subsequently automatic) analytical process. In other systems, the analytical process, to

some degree, is manually controlled. 3.2 The actual process can vary substantially from instrument to instrument, since a variety of means can be utilized to effect the primary requirements of the test methods. All satisfactory processes provide for the following: 3.2.1 The conversion of the subject materials (in their entirety) to carbon dioxide, water vapor, and elemental nitrogen, respectively, and 3.2.2 The subsequent, quantitative determination of these gases in an appropriate gas stream. 3.3 The conversion of the subject materials to their corresponding gases takes place largely during combustion of the sample at an elevated temperature in an atmosphere of purified oxygen. Here, a variety of gaseous materials are produced, including the following: 3.3. l Carbon dioxide from the oxidation of organic and elemental carbon, 3.3.2 Hydrogen halides from organic halides (and organic hydrogen, as required), 3.3.3 Water vapor from the oxidation of (the remaining) organic hydrogen and the liberation of moisture, 3.3.4 Nitrogen and nitrogen oxides from the oxidation of organic nitrogen, and 3.3.5 Sulfur oxides from the oxidation of organic sulfur. In some systems, sulfurous and sulfuric acids can also be obtained from a combination of the sulfur oxides and the water vapor. 3.4 There are several accepted ways of isolating the desired gaseous products and quantitatively determining them. These are as follows: 3.4.1 Test Method A~--From the combustion product gas stream, oxides of sulfur are removed with calcium oxide in the secondary combustion zone. A portion of the remaining mixed gases is carried by helium gas over a hot copper train to remove oxygen, and reduce NO~ to N2, over NaOH to remove CO2, and over magnesium perchlorate to remove H20. The remaining elemental nitrogen is measured by the thermal conductivity cell. Simultaneously, but separately from the nitrogen measurement, the carbon and hydrogen selective infrared cells measure the CO2 and H20 levels. 3.4.2 Test Method B4--From the combustion product gas stream (which is cleaned from sulfur oxides, excess oxygen, etc. as in 3.4.1), the remaining CO2, water vapor, and N2 are flushed into a mixing chamber and are thoroughly homoge-

J These test methods are under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and are the direct responsibility of Subcommittee D02.03.0B on Spectrometric Methods. Current edition approved April 10, 1996. Published June 1996. Originally published as D 5291 - 92. Last previous edition D 5291 - 92. 2 Annual Book of ASTM Standards, Vol 05.02.

3 Leco CHN-600 instrument has been found satisfactory for the analyses in Test Method A, and is available from Leco Corporation, 3000 Lakeview Ave., St. Joseph, MI 49085. 4 Perkin Elmer 240C, 2400 series and CEC 240XA and 440 instruments have been found satisfactory for the analyses in Test Method B and are available from Perkin Elmer Corporation, Main Ave., Norwalk, CT 06856.

1. Scope 1.1 These test methods cover the instrumental determination of carbon, hydrogen, and nitrogen in laboratory samples of petroleum products and lubricants. Values obtained represent the total carbon, the total hydrogen, and the total nitrogen. 1.2 These test methods are applicable to samples such as crude oils, fuel oils, additives, and residues for carbon and hydrogen and nitrogen analysis. These test methods were tested in the concentration range of at least 75 to 87 mass % for carbon, at least 9 to 16 mass % for hydrogen, and < 0.1 to 2 mass % for nitrogen. 1.3 The nitrogen test method is not applicable to light materials or those containing < 0.75 mass % nitrogen, or both, such as gasoline, jet fuel, naphtha, diesel fuel, or chemical solvents. 1.4 These test methods are not recommended for the analysis of volatile materials such as gasoline, gasolineoxygenate blends, or gasoline type aviation turbine fuels. 1.5 The results of these tests can be expressed as mass % carbon, hydrogen or nitrogen. 1.6 The values stated in SI units are to be regarded as the standard. 1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 2. Referenced Documents

2. l A S T M Standards: D4057 Practice for Manual Sampling of Petroleum and Petroleum Products 2 D 4177 Practice for Automatic Sampling of Petroleum and Petroleum Products 2

852

(~ D 5291 nized at a precise volume, temperature, and pressure. After homogenization, the chamber is depressurized to allow the gases to pass through a heated column, where the gases separate as a function of selective retention times. The separation occurs in a stepwise steady-state manner for nitrogen, carbon dioxide, and water. 3.4.3 Test Method CS--The combustion product gas stream, after full oxidation of component gases, is passed over heated copper to remove excess oxygen and reduce NOx to N 2 gas. The gases are then passed through a heated chromatographic column to separate and elute N2, CO2, and H20 in that order. The individual eluted gases are measured by a thermal conductivity detector. 3.5 In all cases, the concentrations of carbon, hydrogen and nitrogen are calculated as functions of the following: 3.5.1 The measured instrumental responses, 3.5.2 The values for response per unit mass for the elements (established via instrument calibration), and 3.5.3 The mass of the sample. 3.6 A capability for performing these computations automatically can be included in the instrumentation utilized for these test methods.

4. Significance and Use 4.1 This is the first ASTM standard covering the simultaneous determination of carbon, hydrogen, and nitrogen in petroleum products and lubricants. 4.2 Carbon, hydrogen, and particularly nitrogen analyses are useful in determining the complex nature of sample types covered by this test method. The CHN results can be used to estimate the processing and refining potentials and yields in the petrochemical industry. 4.3 The concentration of nitrogen is a measure of the presence of nitrogen containing additives. Knowledge of its concentration can be used to predict performance. Some petroleum products also contain naturally occurring nitrogen. Knowledge of hydrogen content in samples is helpful in addressing their performance characteristics. Hydrogen to carbon ratio is useful to assess the performance of upgrading processes. 5. Apparatus 5.1 Since a variety of instrumental components and configurations can be satisfactorily utilized for these test methods, no specifications are given here with respect to overall system design. 5.2 Functionally, however, the following are specified for all instruments: 5.2.1 The conditions for combustion of the sample must be such that (for the full range of applicable samples) the subject components are completely converted to carbon dioxide, water vapor (except for hydrogen associated with volatile halides and sulfur oxides), and nitrogen or nitrogen oxides. Generally, instrumental conditions that affect complete combustion include availability of the oxidant, temperature, and time.

5.2.2 Representative aliquots of the combustion gases must then be treated: 5.2.2.1 To liberate (as water vapor) hydrogen present as hydrogen halides and sulfur oxyacids, and 5.2.2.2 To reduce (to the element) nitrogen present as nitrogen oxides. 5.2.3 The water vapor and nitrogen so obtained must be included with the materials originally present in these aliquots. 5.2.4 Additional treatment of the aliquots (prior to detection) depends on the detection scheme utilized for the instrument (see Note 1). NOTE I - - T h e s e additional treatments can be provided by the instrumental

components utilized to satisfy5.2.2.

5.2.5 The detection system (in its full scope) must determine the analytical gases individually and without interference. Additionally, for each analyte, either: 5.2.5.1 The detectors must provide linear responses with respect to concentration over the full range of possible concentrations from the applicable samples, or 5.2.5.2 The system must include provisions for appropriately evaluating non-linear responses so that they can be accurately correlated with these concentrations. 5.2.6 Such provisions can be integral to the instrumentation, or they can be provided by (auxiliary) computation schemes. 5.2.7 Lastly, except for those systems where the concentration data are output directly, the instrument must include an appropriate readout device for the detector responses. 5.3 Additionally consumables needed for the analyses include: 5.3.1 Tin Capsules, large and small, 5.3.2 Ceramic Crucibles, 5.3.3 Copper Capsules, 5.3.4 Tin Plugs, 5.3.5 Tin Boats, 5.3.6 Copper Plugs, 5.3.7 Aluminum Capsules, 5.3.8 Combustion Tubes, 5.3.9 Adsorption Tubes, 5.3.10 Nickel Capsules, and 5.3. I 1 Reduction Tubes. 5.4 Analytical Balance, capable of weighing to the nearest 0.00001 g. 5.5 Syringes or Pipettes, to transfer the test specimens to capsules.

6. Reagents

6.1 Purity of Reagents--Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chem ical Society, where such specifications are available: Other grades may be used, provided it is first ascertained that the 6 Reagent Chemicals. American Chemical Society Specoqcations, American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed by the American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville, MD.

s Carlo Erba 1106, 1108, and 1500 instruments have been found satisfactory for the analyses in Test Method C and are available from Carlo Erba Strumentazione, Strada Rivoltana, 20090 Rodano, Milan, Italy.

853

({~ D 5291 reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination. 6.2 Calibration Standards--Table 1 lists the pure organic compounds most commonly used to calibrate the instruments operated according to 3.4.1 through 3.4.3; other suitable pure compounds can also be used. 6.3 Carrier and Combustion Gases: 6.3.1 Oxygen, high purity (99.998 %), 6.3.2 Helium, high purity (99.995 %), 6.3.3 Compressed Air, Nitrogen, or Argon, for operating pneumatic valves, if needed, and 6.3.4 Carbon Dioxide. 6.4 Additional Reagents (as Specified by the Instrument Manufacturer)--This specification covers the reagents utilized to provide for the functional requirements cited in 5.2.2 and 5.2.3. These reagents can vary substantially for different instruments. Consequently, these reagents shall be those recommended by the manufacturer. Specifically, these reagents will be for: 6.4.1 Test Method A3: 6.4.1.1 Sodium Hydroxide Coated Silica, 6.4.1.2 Quartz Wool, 6.4.1.3 Magnesium Perchlorate, 6.4.1.4 Copper Turnings, 6.4.1.5 Coated Calcium Oxide (Furnace Reagent), 6.4.1.6 Nitrogen Catalyst, and 6.4.1.7 Magnesium Oxide7, for liquids. 6.4.2 Test Method IP: 6.4.2.1 EA 1000 Reagents, 6.4.2.2 Silver Tungstate on MgO, 6.4.2.3 Silver Vanadate, 6.4.2.4 Quartz Wool, 6.4.2.5 Silver Gauze, 6.4.2.6 Copper Oxide9, 6.4.2.7 Tungstic Oxide, 6.4.2.8 Cobalt Oxide, 6.4.2.9 Copper Powder, 6.4.2.10 Sodium Hydroxide Coated Silica, 6.4.2.11 Alumina, 6.4.2.12 Magnesium Perchlorate, and 6.4.2.13 Platinum Gauze. 6.4.3 Test Method Cs: 6.4.3.1 Quartz Wool, 6.4.3.2 Chromic Oxide (oxidation catalyst), 6.4.3.3 Silver Coated Cobalt Oxide, 6.4.3.4 Reduced Copper (reduction catalyst), 6.4.3.5 Magnesium Perchlorate, 6.4.3.6 Molecular Sieve, 3A ~/t6 in. (1.6 mm), 6.4.3.7 Sodium Hydroxide Coated Silica, 6.4.3.8 Chromosorb, (Absorber, ~° for liquid samples; cal-

cined silica), and 6.4.3.9 Copper Grains. 7. Sampling, Test Specimens, and Test Units

7.1 Laboratory SamplemTake a representative sample as specified in Practices D 4057 or D 4177. 7.2 Test SpecimenwTake an aliquot from the laboratory sample for analysis as follows: 7.2.1 Preparation--Warm viscous samples until they are fluid, and shake for 5 s. 7.2.2 Transfer--Use any convenient, clean syringe or pipet to transfer test specimens to the capsules as described in Section 9. 8. Preparation of Apparatus

8.1 Prepare the instrumental system (in its entirety) in strict accordance to the manufacturer's instructions. 8.2 Calibrate the system using acetanilide or other suitable calibration standard mentioned in Table 1, using the standardization procedure specified by the manufacturer. This procedure, with respect to the actual analytical process involved, must not differ from that specified for the samples. 8.3 Tubes~Columns Preparation (see Note 2)--Clean all quartz and glass parts prior to use with soap and water followed by acetone, and dry fingerprints must be removed with a grease solvent such as acetone, prior to insertion ofthe tubes into the furnace. Handle the tubes using appropriate gloves, such as lint-free cotton gloves, that will not leave fingerprints. NOT~ 2 - - A l l c o m b u s t i o n tubes a n d absorption tubes need to be

periodically replaced after 50 to 300 sampleruns. The exact intervals of change should be determined as recommended by the manufacturer. 8.3.1 Test Method A3: 8.3.1.1 Combustion Tube--Pack 5 cm of quartz wool in the bottom of the tube on the primary (inlet) side. Set a ceramic crucible on top of the quartz wool on the primary side. Pack 3.1 cm ofquartz wool in the bottom of the tube on the secondary (outlet) side. Fill 6.3 cm of furnace reagent on top of the quartz wool. Pack I 1.9 cm of quartz wool on top of the furnace reagent. TABLE 1

Calibration Standards for CHN Instrumental Analysis A,e

Compound

Molecular Formula

Carbon, Mass ~

Hydrogen Mass ~,

Nitrogen Mass

CeHeNO C17H~NOa CvHaO= C,=H,,N,O4

71.09 70.56 68.84 51.79

6.71 8.01 4.95 5.07

10.36 4.84

CeH12N204S= CI=Hlo CIoHleN=Oa CaH4N= CaHsNO= ClaH~O=

29.99 93.46 41.10 52.92 58.53 75.99

5.03 6.54 5.52 5.92 4.09 12.76

Sucd,amide

C.H,N=O,

41.37

Sucrose Sulphanllamide Triethanol amine

ClaH2aOtl 42.10 CeHaN=O=S 41.84 CeHtsNOa 48.30

Acetanilide Atropine Benzoic acid Cyclohexanone2,4-dinitrophanylhydrazone Cystine Diphenyl EDTA Imidazol Nicotinic acid Steeric acid

7 Corn-aid, a registered trademark of Leco, has been found suitable for this purpose and is available from Leeo Corporation, 3000 Lakeview Ave., St Joseph, MI 49085. , EA 1000 Reagent is a registered trademark of Perkin Elmer and is available from Perkin Elmer Corporation, Main Ave., Norwalk, CT 06856. 9 Cuprox, a registered trademark of Perkin Elmer, has been found suitable for this purpose and is available from Perkin Elmer Corporation, Main Ave., Norwalk, CT 06856. lo Chromosorb, a registered trademark of Carlo Erba Strumentazione, has been found suitable for this purpose and is available from Carlo Erba Strumentazione, Strada Rivoltana, 20090 Rodano, Milan, Italy.

~>0:14 11.66 ' ~):59 41.15 11.38

894

;,4:13

6.48 4.68 10.13

i 6:27 9.39

A The Merck Index, 10th Edition, Merck and Company, Inc., Rahway, New Jersey, 1983. e Many of these compounds can be obtained from the National Institute of Standards and Technology as well as other commercial chemical manufacturers. such as Alddch, Alfa, Kodak and others. See 6.1 for the pudty of these reagents.

854

o s291 8.3.1.2 Reduction Tube--Insert a small copper plug in the bottom. Fill up to 8.8 cm of N-catalyst on top of the copper plug. Add 13.8 cm of copper turnings on top of the N-catalyst. 8.3.2 Test Method IV: 8.3.2.1 Combustion Tube--Precondition EA 1000s and silver tungstate on magnesium oxide by preheating it at 900"C for 10 to 30 rain. Roll a strip of silver gauze to fit into the combustion tube. Clean the rolled gauze by either ultrasonically washing it in detergent and water, and drying it, or by passing it rapidly over a flame several times until the smoke disappears. Slide 2.5 cm of quartz wool into the tube from the outlet so that the end of the wool meets with the indentations in the tube. Add 5 cm of EA I000 s reagent. Top with a small wad of quartz wool. Add 5 cm of silver tungstate on magnesium oxide. Top with a small wad of quartz wool. Add 2.5 cm of silver vanadate. Top with a small wad of quartz wool. Slide a roll of silver gauze into the combustion tube, so that there is about 1.2 cm empty space left in the tube. Insert 1.2 cm of quartz wool into the inlet end of the combustion tube, and another into the vial receptacle, and place the receptacle into the combustion tube. 8.3.2.2 Reduction Tube--Insert a small wad of quartz wool into the inlet end of the tube to where the tube widens. Then insert a conditioned roll of silver gauze. Fill the tube from the outlet end. Fill with copper powder, occasionally tapping till the copper column is 23.8 cm deep. Insert a small wad of quartz wool, then add 1.2 cm of cuprox (copper oxide), and add another small wad of quartz wool. Insert the copper plug into the outlet end of the reduction tube. 8.3.3 Test Method C5: 8.3.3.1 Combustion Reactor--First place a 2 mm plug of quartz wool in the bottom of the tube. Fill the tube with 50 mm of silver coated cobalt oxide. Insert a 10 mm thick plug of quartz wool. Add 120 mm of chromic oxide. Inset a 10 mm thick plug of quartz wool. Slide the combustion tube into the combustion furnace and secure with the o-ring fittings. 8.3.3.2 Reduction Reactor--First place a 5 mm plug of quartz wool in the bottom of the tube. Fill the tube with reduced copper. Insert a 10 mm thick plug of quartz wool. Slide the reduction tube into the reduction furnace and secure with the o-ring fittings. 8.3.3.3 Water Trap---First place a 10 mm plug of quartz wool in the bottom of the tube. Fill the tube with 3A 1/16in. (1.6 mm) molecular sieve or magnesium perchlorate, s Insert a 10 mm thick plug of quartz wool. Secure the tube in the water trap bracket. 8.3.3.4 Carbon Dioxide Trap--First place a 10 mm plug of quartz wool in the bottom of the tube. Fill the tube with 50 mm of magnesium perchlorate. Add 130 mm of sodium hydroxide coated silica. 7 Add 50 mm of magnesium perchlorate. Insert a 10 mm thick plug of quartz wool. Secure the tube in the carbon dioxide trap bracket.

9. I. I. 1 Weigh the solid samples in tin capsules. 9. I. 1.2 Weigh the liquid samples in copper capsules and saturate with an absorbent (magnesium oxide9) within the copper capsules. Seal the copper capsules with tin plugs. These precautions will induce a slower combustion to prevent any back flashes with the light samples, or incomplete sample combustion. 9.1.2 The following typical settings may be used. 9.1.2.1 Temperatures: Combustion furnace; primary zone Combustion furnace; secondary zone Catalyst heater Oven chamber

950"C 950'C 750"C 5YC

9.1.2.2 Oxygen and helium carder gas pressures should be 40 psi each. 9.1.2.3 Typical settings for gas flows are: Helium---400 cm3/min (normal flow) 70 em3/min (conservation flow) Oxygen--7 dm3/min Air--6 dm3/min

9.1.3 To start the sequence of analysis, run two to four blank capsules, followed by five calibration standards. The results must agree within ±10 % for blanks, and 4-1% of the theoretical value for calibration standards. 9.1.4 Hold all the results in the instrument memory, and recall the best values for the calibration. Enter these results and the known calibrant concentrations into the microprocessor to generate a one point calibration curve. 9.1.5 Analyze the calibration standard again to check the new curve. The results should differ by less than 1%, or repeat the calibration. 9.1.6 Combust the encapsulated sample in a manner similar to the calibrant. Depending on the sample matrices, set varying oxygen flow rates and combustion times to overcome incomplete combustion. 9.2 Test Method B4: 9.2.1 Accurately to within 4-0.02 mg weigh out 2 to 4 mg of a homogeneous test specimen taken according to Practices D 4057 or D 4177, into the vial. Pinch the center of the vial with a forceps and fold it in half. Flatten the vial with the tweezers, and fold the vial in thirds. 9.2.2 The following typical settings may be used. Combustion Temperature Reduction temperature Detector oven temperature Helium Oxygen Air, nitrogen, or argon

975"C 640"C 80 to 84"C 137.9 kPa 110.3 kPa 413.7 kPa

9.2.3 Run two to four blanks through the system. Run a conditioning sample followed by another blank. Repeat this sequence. 9.2.4 Run a calibration standard and obtain a response factor, (K), that is calculated as: detector counts for standard/mass of nitrogen, carbon, or hydrogen in the standard. 9.2.5 If the response factors obtained are Within manufacturer's specifications, run the samples. 9.3 Test Method CJ: 9.3.1 Accurately to Within +0.02 mg weigh out about 5 mg of homogeneous test specimen taken according to Practices D4057 or D 4177, in a tin capsule. Crimp the capsule closed With a forceps. 9.3.2 For liquid samples, add about 30 mg of

9. Procedure

9.1 Test Method A3: 9.1.1 Accurately to within + 1 mg weigh out about 50 to 200 mg of homogenous test specimen taken according to Practices D 4057 or D 4177, in a capsule. Crimp the capsule with a forceps. 855

~

D 5291 D -- the mass of the sample, mg, E = the mass of the standard, rag, and F = the percent of the carbon, hydrogen or nitrogen in the standard, mass %. 10.2 The calculation can be automatically provided by the instrumental system used for these test methods.

Chromosorb ~° to the tin capsule after weighing the sample. 9.3.3 The following typical settings may be used. Combustion temperature Reduction temperature Detector oven temperature Detector filament temperature Analysis cycle Autosample inject Autosample return Oxygen inject time Integration window delay

1020"C 650'C 60 to IO0°C 190"C 420 s Start20 s Stop 70 s 70 s 2s

11. Report 11. I Report the carbon, hydrogen, and nitrogen results as mass percent of the sample.

9.3.4 Typical settings for gas flows are:

Oxygen Helium

Line Pressure 100 kPa 200 kPa

Air

500 kPa

12. Precision and B i a s It 12.1 Precision:

Flow Rate 20 cm3/min Reference detector---40 cma/min Measure detector--80 cm3/min Sample purge--60 cm3/min 3.5 kg/cm 2

12.1.1 Repeatability and Reproducibility--The repeatability and reproducibility of these test methods (D 5291) for measuring carbon, hydrogen, and nitrogen were determined in a round robin that involved 26 laboratories and fourteen petroleum based samples. A research report based on this round robin is available. It Based on this round robin, the following repeatability and reproducibility for these test methods (D 5291) can be expected. This is a joint precision based on all three test methods. No relative bias was found among these test methods.

9.3.5 To start the sequence of analysis, run one unweighed sample to determine retention times, followed by one to two blank capsules, two to three calibration samples for a response factor calculation or three to six calibration samples for a linear regression calculation, then unknown samples. 9.3.6 Randomly insert standards during the analysis of samples to check and update the calibration.The placement and frequency of standards is dependent on sample type and change in analytical conditions, however, a good rule of thumb is one standard for every ten samples.

Carbon Hydrogen Nitro~n

BxExF CxD

Reproducibility (x + 48.48)0,018 (x°.s)0.2314 0.4456

where: x = the mean value. 12.2 BiasmSince there is no accepted petroleum based reference material suitable for determining the bias for the procedure in these test methods (D 5291) for measuring carbon, hydrogen and nitrogen in petroleum products and lubricants, bias cannot be determined.

10. Calculation 10.1 Calculate the concentrations of carbon, hydrogen, and nitrogen, on the appropriate sample basis, as follows: A =

Concentration Repeatability Range (mass %) 75 to 87 (x + 48.48)0.0072 9 to 16 (x°.5)0.1162 0.75 to 2.5 0.1670

(1)

where: A = the percent of the carbon, hydrogen or nitrogen in the sample, mass %, B = the detector response for carbon, hydrogen or nitrogen in the sample minus response from blank, C = the detector response for carbon, hydrogen or nitrogen in the standard minus response from blank,

13. K e y w o r d s 13.1 carbon content; CHN analysis; CHN instruments; hydrogen content; nitrogen content sj Round robin data for these test methods can be obtained from ASTM Headquarters. Request RR:D02-1289.

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted In connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responaiblllty. This standard is subject to revision at any time by the responalble technical committee and must be reviewed every five years and ff not revised, either reepproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful con#ldaratlon at a meeting of the responsible tanhnlcal committee, which you may attend, ff you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 100 Barr Harbor Drive, West Conshohocken, PA 19428.

856

(~,)

Designation: D 5292 - 93 Standard Test Method for Aromatic Carbon Contents of Hydrocarbon Oils by High Resolution Nuclear Magnetic Resonance Spectroscopy I This standard is issued under the fixed designation D 5292; the number immediately following the dt~ienation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript q:~ilon (0 ind~_J_~ an editorial change since the last revision or reapproval.

1. Scope 1.1 This test method covers the determination of the aromatic hydrogen content (Procedures A and B) and aromatic carbon content (Procedure C) of hydrocarbon otis using high-resolution nuclear magnetic resonance (NMR) spectrometers. Applicable samples include kerosenes, gas otis, mineral oils, lubricating otis, coal liquids, and other distillates that are completely soluble in chloroform and carbon tetrachloride at ambient temperature. For pulse Fourier transform (FI') spectrometers, the detection limit is typically 0.1 tool % aromatic hydrogen atoms and 0.5 mol % aromatic carbon atoms. For continuous wave (CW) spectrometers, which are suitable for measuring aromatic hydrogen contents only, the detection limit is considerably higher and typically 0.5 tool % aromatic hydrogen atoms. 1.2 The reported units are mole percent aromatic hydrogen atoms and mole percent aromatic carbon atoms. 1.3 This test method is not applicable to samples containing more than 1 mass % olefinic or phenolic compounds. 1.4 This test method does not cover the determination of the percentage mass of aromatic compounds in otis since NMR signals from both saturated hydrocarbons and aliphatic substituents on aromatic ring compounds appear in the same chemical shift region. For the determination of mass or volume percent aromatics in hydrocarbon otis, chromatographic, or mass spectrometry methods can be used. 1.5 The values stated in SI units are to be regarded as the standard. 1.6 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Specific precautionary statements are given in Notes 1, 2 and 3.

2. Referenced Documents 2.1 A S T M Standards: D 3238 Test Method for Calculation of Carbon Distribution and Structural Group Analysis of Petroleum Oils by the n-d-M Method2

D 3701 Test Method for Hydrogen Content of Aviation Turbine Fuels by Low Resolution Nuclear Magnetic Resonance Spectrometry2 D 4057 Practice for Manual Sampling of Petroleum and Petroleum Products2 E 386 Practice for Data Presentation Relating to HighResolution Nuclear Magnetic Resonance (NMR) Spectroscopy 3

2.2 Institute of Petroleum Methods: IP Proposed Method BD Aromatic Hydrogen and Aromatic Carbon Contents of Hydrocarbon Oils by High Resolution Nuclear Magnetic Resonance Spectroscopy4 3. Terminology 3.1 Descriptions of Terms Specific to This Standard: 3.1.1 aromatic carbon content--mole percent aromatic carbon atoms or the percentage of aromatic carbon of the total carbon: aromatic carbon content ,,, 100 x (aromatic carbon atoms)/(total carbon atoms) (1) 3.1.1.1 Discussion--For example, the aromatic carbon content of toluene is 100 x (6/7) or 85.7 tool % aromatic carbon atoms. 3.1.2 aromatic hydrogen content--mole percent aromatic hydrogen atoms or the percentage of aromatic hydrogen of the total hydrogen: aromatic hydrogen content ffi 100 x (aromatic hydrogen atoms)/(total hydrogen atoms) (2) 3.1.2.1 Discussion--For example, the aromatic hydrogen content of toluene is 100 × (5/8) or 62.5 mol % aromatic hydrogen atoms. 3.2 Definitions of chemical shift (reported in parts per million (ppm)), internal reference, spectral width, and other NMR terminology used in this test method can be found in Practice E 386. 3.3 Chloroform-d refers to chloroform solvent in which hydrogen is replaced by deuterium, the heavier isotope of hydrogen. Chloroform-d is available from a variety of chemical and isotope suppliers.

4. Summary of Test Method 4.1 Hydrogen (JH) nuclear magnetic resonance (NMR) spectra are obtained on solutions of the sample in either carbon tetrachloride or chloroform-d, using a CW or pulse FT high-resolution NMR spectrometer. Carbon ('3C) NMR

s This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.04 on Hydrocarbon Analysi~ Current edition approved Aug. 15, 1993. Published October 1993. Originally published as D 5292 - 92. Last previous edition D 5292 - 92. 2 Annual Book of ASTM Standards, Vol 05.02.

3 Annual Book of ASTM Standards, Vol 14.01. 4 Available from Institute of Petroleum Standards.

857

~

D 5292

spectra are obtained on solutions of the sample in chloroform-d using a pulse FT high-resolution NMR spectrometer. Tetramethylsilane is preferred as an internal reference in these solvents for assigning the 0.0 parts per million (ppm) chemical shift position in both ~H and ~3C NMR spectra. 4.2 The aromatic hydrogen content of the sample is measured by comparing the integral for the aromatic hydrogen band in the ~H NMR spectrum (5.0 to 10.0 ppm chemical shift region) with the sum of the integrals for both the aliphatic hydrogen band (--0.5 to 5.0 ppm region) and the aromatic hydrogen band (5.0 to 10.0 ppm region). 4.3 The aromatic carbon content of the sample is measured by comparing the integral for the aromatic carbon band in the m3C spectrum (100 to 170 ppm chemical shift region) with the sum of the integrals for both the aliphatic carbon band (-10 to 70 ppm region) and the aromatic carbon band (100 to 170 ppm region). 4.4 The integral of the aromatic hydrogen band must be corrected for the NMR absorption line due to residual chloroform (7,25 ppm chemical shift) in the predominantly chloroform-d solvent. 4.5 The integrals of the aliphatic hydrogen band and of the aliphatic carbon band must be corrected for the NMR absorption line due to the internal chemical shift reference tetramethylsilane (0.0 ppm chemical shift in both ~H and ~3C spectra). 5. Significance and Use

5.1 Aromatic content is a key characteristic of hydrocarbon oils and can affect a variety of properties of the oil including its boiling range, viscosity, stability, and compatibility of the oil with polymers. 5.2 Existing methods for estimating aromatic contents use physical measurements, such as refractive index, density, and number average molecular weight (see Test Method D 3238) or infrared absorbance ~ and often depend on the availability of suitable standards. These NMR procedures do not require standards of known aromatic hydrogen or aromatic carbon contents and are applicable to a wide range of hydrocarbon oils that are completely soluble in chloroform and carbon tetrachloride at ambient temperature. 5.3 The aromatic hydrogen and aromatic carbon contents determined by this test method can be used to evaluate changes in aromatic contents of hydrocarbon oils due to changes in processing conditions and to develop processing models in which the aromatic content of the hydrocarbon oil is a key processing indicator.

TABLE 1 Sample and Instrument Conditions for Continuous Wave (CW) Measurements of 1H NMR Spectra Solvent ~ o¢carbtmt e t r ~ Samp~ conoentrat~ up to ~ s v/v f~ cktalabae~ Sampaetemperature InstnJiqn~ntm1101ent Intorn~ lock None Sarn~ q~nlng rate ~ reemmw~ck~d ~ rr~uf~'tur~,t,/r~caUy~ ~ r-f Power level JuJri~mnlmmdi~d~ k ~ s t ~ t m m u f a c t ~ S~n~ to no~e ~ve~ A nlkllmum~ 5:I forthe maxlmum helght~ tlle ~ ~d0~M~rptkz ~ ¢Wt reference ~ ~ (0.0~ ) at no ~ lJlanI vol ~ oor1~ontnmtlon Integration ~t~raW overthe range -O.S to 5.0 ~ ~ aliphatJoI~nd and 5.0 to 10.0 ppm for the aroma~ blind

or pulse FT techniques but t3C measurements require signal averaging and, therefore, currently require the pulse FT technique. Low resolution NMR spectrometers and proce. dures are not discussed in this test method (see Test Method D 3701 for an example of the use of low resolution NMR). 6.2 Tube Tubes--Usually a 5 or 10 mm outside diameter tube compatible with the configuration of the CW or pulse FT spectrometer. 7. Reagents and Materials

7.1 Purityof Reagents--Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, where such specifications are available. 6 Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use. 7.2 Chloroform-d--For IH NMR, chloroform-d must contain less than 0.2 vol % residual chloroform. Care must be taken not to contaminate the solvent with water and other extraneous materials. Ntyrl~ 1: Waraine~Health hazard. Highly toxic. Cancer suspect agent. Can be fatal when swallowedand harmful when inhaled. Can produce toxic vapors when burned. 7.3 Carbon TetrachloridemSpectrophotometricgrade solvent should be used. Care must be taken not to contaminate the solvent with water and other extraneous materials. NOTE 2: Warnla~Health hazard. Toxic. Cancersuspectagent. Can be fatal when swallowedand harmful when inhaled. Can producetoxic vapors when burned.

6. Apparatus

7.4 Tetramethylsilane,American Chemical Society (ACS) reagent internal chemical shift reference for IH and 13C NMR spectra. Nor~ 3: Warning--Flammable liquid.

6.1 High.Resolution Nuclear Magnetic Resonance Spectrometer--A high-resolution continuous wave (CW) or pulse

7.5 Chromium (Ill) 2,4-Pentanedionate, relaxation reagent for m3CNMR spectra, typically 97 % grade.

Fourier transform (FT) N-MR spectrometer capable of being operated according to the conditions in Tables 1 and 2 and of producing peaks having widths less than the frequency ranges of the majority of chemical shifts and coupling constants for the measured nucleus. 6.1.1 ~H NMR spectra can be obtained using either CW

8. Sampling

8.1 It is assumed that a representative sample acquired by a procedure of Practice D 4057 or equivalent has been

s Brande.~,G., "The Structural Groupsof PetroleumFractions. I. Structural

Group AnalysisWiththe Helpof Infrared Spectroscopy,"Brennstoff-ChemieVol

37, 1956.p. 263.

858

"ReagentChemical~AmericanChemicalSocietySpecification."American ChemicalSociety,Washington,D.C.Forsuggestionson the te~ns ofreagentsnot listed by the AmericanChemicalSociety,see "AnalarStandardsfor Laboratory U.IC Chemicalt" BDH Ltd., Pnole, Donet, and the "United States Pharamacopela."

~ D 5292 TABLE 2 Sample end Instrument Conditions for Pulse Fourier Transform Measurements of 1H end 1=C NMR Spectre So~v~ 1HNMR I~NMR

Chlorc4orm-d

Sampleconcentmtlon: 1HNMR

Must be optimized for the Instrument In use but

ISCNMR Relaxation agent

Sam~ mmp~atum I n W lock

s a n ~ mnn~0rem IH Deo:~pllno

or cadx~ teVachlorlde

may t~ m high == 5 S v/v Up to s e ~ v/v ~" petroleum distUlat~ and 30~ v/v ~ co= , q u ~ OvontJm (m) 2,4-pentan~t0nm ~ e d for laC NMR IIOlutlons only. Where used, I120 mM soaaOon(about 10 m0 per mL) Inl~ amb~mt l ~ u t ~ u m (wh~ chJoroform-d Is usKI for 1H NMR) AI recommended by n~mufacturer, t y p ~ 20 Hz Only for IsC NMR. Broadband over the who~eof the IH fnKluetcy rlmge, gated on dudng laC

damscqcmonon~ v~ths decoup~rim Ume

P , ~ ~ ano~ Sequence ¢l~y time:

leu than 2 m/s AWOX~T=te~ 30" ~H NMR > 10 s 1=C NMR > 3 s with and > 60 s without relaxation agent

Memory ¢ze for acquum~: Spectral wlo~: IH NMR

Choo~ to O~ a ~

O ~ n 0 roteof 0.S

Hz/point foe IH and 1.2 Hz/point for 1~C NMR. If n~esuty, Increasem~m~y size and zero BI .at least 15 ppm In Irequency and centered, as do~e ~ poodle, to the 5 ppm ct~#cal shift

value

Exponential llne

At le~t 250 plan In frequency and centered, u d o ~ U pouib~, to the 100 ppm chemical shift value Set to be equal to or greater than the spectral width and as permitted by the instrument's filter hardware Set st least equal to the digitizing rate

Slgnalto nobe leveb: IH NMR

A~

I~CNMR

Filter bandwidth

I~CNMR Chemical shlft reference: IH NMR I~CNMR

Integration: ~H NMR ISCNMR

of 20:1 for the maximum height of the btegretad band A mlnlmum of 60:1 for the mcximum height of the ¢hlorofetm.d resonance appeadng between 75 and 80 ppm on the chemical mlft scale

Preferebly tetreme',hylsllane (0.0 ppm) at no greater than I v~ ~ ¢oncentraUon Preferably tetramethy~aee (0.0 ppm) at no greater than I voJ ~ concentration, ff th~ reference Is not uud, the ¢enU'alp e ~ of chlorofom~ Is set to 77.0 ppm Integrete over tl~ range -0.5 to 5.0 Plxn for the ~hatl¢ band and 5.0 to 1o.0 ppm for the aromat~ band Integrate over the range -10 to 70 pprn for the ~iphaU¢ bend m~d 100 to 170 ppm for the ~omstlc band

received in the laboratory. If the test is not to be conducted immediately upon receipt of the sample, store in a cool place until needed. 8.2 A minimum of approximately 10 mL of sample is required for this test method. This should allow duplicate determinations, if desired. 8.3 All samples must be homogeneous prior to subsampling. If any suspended particles present are attributable to foreign matter such as rust, fdter a portion of the sample to be tested through a small plug of glass wool, contained in a clean small funnel, into a clean and dry vial or NMR sample tube containing the appropriate NMR solvent.

8.4 If the sample contains waxy materials, heat the sample in the container to approximately 600C and mix with a high-shear mixer prior to sampling. It may be necessary to transfer a portion of the sample to an NMR tube containing the appropriate solvent by means of a pipet which has been heated to approximately 60"C to maintain the homogeneity of the sample. 8.5 For a valid test result, samples must be completely soluble in chloroform.
fl~ D 5292 1H FT N M R 1H C W

NMR

x8 X 32

I

....

I...,

............

~,,,,[,,,.,....~.*.

. . . . .

I.,,~1

X1 I 8

I 6

I 4

I 2

10

I 0

8 RG. 2

PPM FIG. 1 60 MHz ~H NMR Spectrum of • Gas Oil

6

4

2

0

PPM $0 MHz IH NMR Spectrum of a Gas Oil

ppm in the mHNMR spectrum) from the total integral value for Region A. If a residual chloroform absorption line is not apparent or if carbon tetrachloridc was used as solvent, make no correction to the Region A integral value. 9.7.7 Iftetramethylsilane was used as an internal chemical shift reference, subtract the portion of integral contributed by the NMR absorption line of TMS (0.0 ppm in the IH NMR spectrum) from the total integral value for Region B. 9.7.8 Calculate the aromatic hydrogen content using the corrected integral values for Regions A and B and the instructions in 10.1 and 10.2. 9.8 Procedure C--I3C NMR Measurements Using a Pulse Fourier Transform (FT) NMR Spectrometer: 9.8.1 Pipette a homogeneous sample of the hydrocarbon oil into an N-MR sample tube compatible with the configuration of the pulse FT spectrometer, usually a 5 or 10 mm outside diameter capped NMR tube. 9.8.2 If a relaxation reagent is used, weigh 10 mg of chromium 2,4-pentanedionate per 1 mL of final solution volume directly into the tube or vial containing the hydrocarbon oil. NOTE 4--A relaxation reagent is recommended but is not required for this procedure (see XI.4.3). If relaxation reagent is not used, however, the "sequence delay time" (see Practice E 386) instrumental setting must be increased to a significantly longer time than that used when relaxation reagent is present. Failure to use the longer "sequence delay time" as indicated in Table 2 will generate erroneous results. 9.8.3 Add chloroform-d to the NMR sample tube to generate a final solution consisting of up to 50 % v/v for petroleum distillates in solvent and up to 30 % v/v for coal liquids in solvent. The concentrations of sample oil in solvent should be optimized for the spectrometer in use but can be as high as the indicated values. Check to ensure that the final solution is homogeneous and free of undissolved particles. 9.8.4 Using the instrumental conditions indicated in Table 2, acquire and plot the pulse FT J3C NMR spectrum. If tetramethylsilane has been used as an internal standard, assign this absorption a chemical shift value of 0.0 ppm. 9.8.5 Figure 3 shows an acceptable pulse FT 13C NMR spectrum of a gas oil test sample dissolved in chloroform-d containing relaxation reagent. 9.8.6 Integrate the NMR spectrum over two chemical shift regions, from 100 to 170 ppm (Region A) and from - 1 0

shift regions, from 5.0 to 10.0 ppm (Region A) and from -0.5 to 5.0 ppm (Region B). See Appendix XI for recommendations on the integration procedure. 9.6.6 If chloroform-d was used as solvent, subtract the portion of integral contributed by the NMR absorption line of residual chloroform solvent (7.25 ppm in the IH NMR spectrum) from the total integral value for Region A. If a residual chloroform absorption line is not apparent or if carbon tetrachloride was used as solvent, make no correction to the Region A integral value. 9.6.7 Iftetramethylsilane was used as an internal chemical shift reference, subtract the portion of integral contributed by the NMR absorption line of TMS (0.0 ppm in the ~H NMR spectrum) from the total integral value for Region B. 9.6.8 Calculate the aromatic hydrogen content using the corrected integral values for Regions A and B and the instructions in I0.1 and 10.2. 9.7 Procedure B--~ H NMR Measurements Using a Pulse Fourier Transform (FT) NMR Spectrometer: 9.7.1 Pipette a homogeneous sample of the hydrocarbon oil into an NMR sample tube compatible with the configuration of the pulse FT spectrometer, usually a 5 or 10 mm outside diameter capped NMR tube. 9.7.2 Add chloroform-d or carbon tetrachloride to the NMR sample tube to generate a final solution consisting of up to 5 % v/v hydrocarbon oil in solvent. The concentration of hydrocarbon oil in solvent should be optimized for the spectrometer in use but can be as high as the indicated value. Check to ensure that the final solution is homogeneous and free of undissolved particles. 9.7.3 Using the instrumental conditions indicated in Table 2, acquire and plot the pulse FT ~H NMR spectrum. If tetramethylsilane has been used as an internal standard, assign this absorption a chemical shift value of 0.0 ppm. 9.7.4 Figure 2 shows an acceptable pulse FT ~H NMR spectrum of a gas oil test sample dissolved in chloroform-d. 9.7.5 Integrate the NMR spectrum over two chemical shift regions, from 5.0 to 10.0 ppm (Region A) and from -0.5 to 5.0 ppm (Region B). See Appendix 1 for recommendations on the integration procedure. 9.7.6 Subtract the portion of integral contributed by the NMR absorption line of residual chloroform solvent (7.25 860

q~ D 5292 12. Precision and Bias 7 12.1 The precision of this test method is dependent on the aromatic content of the sample. 12.2 Precision--The precision of this test method as determined by the statistical examination of inter-laboratory test results in the range I to 78 (aromatic hydrogen content) and 8 to 93 (aromatic carbon content) is as follows: 12.2.1 Repeatability--The difference between successive results obtained by the same operator with the same apparatus under constant operating conditions or identical test material would, in the long run, in the normal and correct operation of this test method, exceed the following values only in one case in twenty:

~aC FT

J

i

}coc _

I

,

200

°

,

,

I

°

150 FIG. 8

100

~t,t._

,

,

,

,,,

I,,

100 PPM

I,

50

MHz 'aC NMR Spectrum

,,

I

,

,

0 of s Gas

(Aromatic Hydropn) Content

(Aromatic Carbon) Content

(% H(Ar)) 0.32 X~

(% C(Ar)) 0.59 X ~

Where X is the aromatic content determined from the NMR measurement. 12.2.2 Reproducibility---The difference between two single and independent results obtained by different operators working in different laboratories on identical test materials would, in the long run, exceed the following values only in one case in twenty:

Oil

to 70 ppm (Region B). See Appendix I for recommendations on the integration procedure. 9.8.7 If tetramethylsilane has been used as an internal chemical shift reference, subtract the portion of integral contributed by the NMR absorption line of TMS (0.0 ppm in the 13C NMR spectrum) from the total integral value for Region B. 9.8.8 Calculate the aromatic carbon content using the corrected integral values for Regions A and B and the instructions in 10.1 and 10.3.

Where X is the aromatic content determined from the NMR measurement.

10. Calculation 10.1 Calculate the aromatic hydrogen or aromatic carbon content as follows: aromatic hydrogen or aromatic carbon content

NOTE 5--Precision limits are based on a round-robin test program carried out in 1985 and 1986 by the Institute of Petroleum (see IP Method BD) and ASTM Committee D02.04F. Twelve cooperator laboratories tested five oils, namely a lubricating oil, a gas oil, two aromatic distillates, and an anthracene oil, whose aromatic hydrogen and carbon contents varied as describedin 13.2.

= [AI(A + B)] × lO0 %

(3)

(Aromatic Hydrosen) Content

(Aromatic Carbon) Content

(% H(Ar))

(% C(Ar))

0.49 X vs

1.37 A'~

12.2.3 Bias--For pure hydrocarbons consisting of a single compound or a known mixture of known aromatic compounds where the aromatic hydrogen or carbon content is either known from the compound molecular structure or can be calculated from the known concentrations of different molecular structures, no bias of the NMR method with respect to the known or calculated value is observed. Since there is no accepted reference method suitable for measuring bias on a hydrocarbon oil composed of an unknown mixture of many aromatic compounds, the bias cannot be determined on such materials.

where: A ffi integral value of the aromatic portion of the spectrum, and B ffi integral value of the aliphatic portion of the spectrum. 10.2 For the aromatic hydrogen content: A is the corrected integral value for Region A (from 5.0 to 10.0 ppm) and B is the corrected integral value for Region B (from -0.5 to 5.0 ppm). The result is expressed as mole percent aromatic hydrogen atoms or % H(Ar). 10.3 For the aromatic carbon content: A is the integral value for Region A (from 100 to 170 ppm) and B is the corrected integral value for Region B (from - 1 0 to 70 ppm). The result is expressed as mole percent aromatic carbon atoms or % C(Ar).

13. Keywords 13.1 aromatic carbon content; aromatic hydrogen content; continuous wave; Fourier transform; hydrocarbon oils; N-MR; nuclear magnetic resonance spectroscopy

11. Report 11.1 Report the mole percent aromatic hydrogen atoms or the mole percent aromatic carbon atoms to one decimal

The results of the cooperative test program, from which these values have been derived, are filed at ASTM H_~_dqearters.

place.

861

~

D 5292

APPENDIX

(Nonmandatory Information) Xl. GENERAL OPERATING GUIDELINES FOR HIGH-RESOLUTION NMR SPECrROSCOPY X 1.1 The following guidelines are to be used in conjunction with the spectrometer manufacturer's instructions for optimum performance of the NMR spectrometer supplemented by the information contained in Practice E 386. X 1.2 Practicesfor Obtaining Acceptable High.Resolution

NMR Spectra: X I.2.1 The homogeneity of the instrument's magnetic field must be optimized so that the best possible spectral resolution and signal to noise ratio are obtained. The tuning of the detector must also be optimized according to the manufacturer's instructions. XI.2.2 The solution concentration should remain constant from sample to sample for both IH and 13C NMR measurements. In order to ensure an accurate integration in a CW spectrum, the solution concentration must be such that a sufficiently good signal to noise ratio is obtained on the smallest hand to be measured. Signal averaging in pulse FT NMR should continue until a similar condition is reached. Recommended signal to noise ratios for CW and pulse FT NMR techniques are indicated in Tables 1 and 2.

X 1.3 NMR Chemical Shift References for NMR Spectra: X 1.3.1 The preferred internal reference compound for ~H NMR spectra is tetramethylsilane (TMS). The ~H chemical shift position for the single 'H NMR absorption line observed for this compound is defined as 0.0 ppm. XI.3.1 The preferred internal reference compound for ~3C NMR spectra is tetramethylsilane (TMS). The ~3C chemical shift position for the single '3C NMR absorption line observed for this compound is defined as 0.0 ppm. XI.4 Quantitative Measurements by High-Resolution

NMR Spectroscopy: XI.4.1 Quantitative CW spectra can be obtained provided the signals are not saturated by the application of the radiofrequency (r-f) field at too high a power level. Consult the spectrometer manufacturer's instructions for recommended r-f field settings. XI.4.2 Quantitative FT spectra which are acquired by collecting the signal response following short r-f pulses require the consideration of a number of parameters. The duration and the spacing of the r-f pulses must be selected to ensure that the sample's mH a n d J3C nuclei return to an equilibrium condition between pulses. Since this return to equilibrium occurs rapidly in IH NMR (usually between 1 to 5 s) and a good signal to noise ratio can usually be obtained in a short time ofdata acquisition, quantitative results can be obtained in ~H NMR without placing major constraints on instrument time. XI.4.3 The corresponding relaxation times for 13C NMR are much longer (usually between 2 to 20 s) and, coupled with its decreased sensitivity compared to IH NMR, a considerable time of data acquisition can be required to obtain quantitative ~3C NMR results. Adding a suitable paramagnetic relaxation reagent, such as chromium (III)

862

2,4-pentanedionate, to the sample is recommended as a means to reduce the relaxation times of all the carbon-13 nuclei and, in so doing, shorten the time required between r-f irradiation pulses. The relaxation reagent does not change the number of scans that must be averaged to achieve an acceptable signal to noise ratio, however. X1.4.4 Carbon-i3 NMR spectra are acquired under conditions such that the spin-spin coupling interaction between hydrogen and carbon nuclei is removed or decoupled. Under certain hydrogen decoupling conditions, however, energy transfer from hydrogen to carbon nuclei may result in an enhancement in the carbon signal intensity known as the nuclear Overhauser enhancement (nOe) (see Practice E 386). The magnitude of this effect is broadly dependent on the number of hydrogen atoms bonded to a particular carbon, the chemical environment of the specific carbon, and the magnetic field strength. In order to suppress this phenomenon and avoid distorted integral data, gated decoupling must be used in which the hydrogen decoupler is only switched on during acquisition of the 13C signals. Gated decoupling should be used in conjunction with the relaxation reagent indicated in XI.3.3 to minimize the nOe effect on the '3C NMR integral data. XI.4.5 The NMR spectrum obtained after Fourier transformation on a pulse FT spectrometer should have a computer-limited spectral resolution sufficient to accurately define the aromatic and aliphatic absorption hands. X 1.4.6 The NMR spectrum must also have a reasonably flat baseline over the entire spectral region so that the areas under these absorption bands can be accurately integrated. Two techniques are available to obtain flat baselines: optimization of the pulse FT data acquisition conditions (receiver dead time, filter band width, etc.) and computer-assisted baseline correction of the NMR spectrum after Fourier transformation. The fu'st technique is preferable although often unachievable in practice. The second technique should be applied with caution as it can cause distortions in the spectrum and in the integral. Consult the spectrometer manufacturer's instructions for recommended baseline correction procedures. XI.4.7 It is absolutely essential that the spectrum, whether collected on a pulse FT or CW spectrometer, be phased correctly before the integrals are measured. Consult the instrument manufacturer's instructions for proper and improper spectrum phasing. Power spectrum or absolute value spectrum options must not be used. XI.4.8 In order to obtain accurate integral data, analog integral traces must be horizontal both before and after the peak or hand being integrated. XI.4.9 Vertical expansion of the analog integral traces must be as large as possible. If using manual measuring methods, maximize the integral trace by vertical expansion and check again that the integral trace is horizontal both before and after the peak or hand being integrated.

~

D 5292

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted In connection with any item mentioned in this standard. Users of this standard ere expressly advised that determination of the validity of any such patent rights, and the risk of Infringement of such rights, ere entirely their own reaponslbitity. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and ff not revised, either reepproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be an~lrossed to ASTM Headquarters. Your comments will receive careful consideration at a me~ir~ of the respoP.slble technical commMee, which you may attend. If you feel that your Gommant.t ~~ve not received a fair heerlng you should make your views known to the ASTM Committee on Standards, 1916 Race St., Phliedelphla, PA 19103,

863

~[~

Designation:D 5303 - 92

Standard Test Method for Trace Carbonyl Sulfide in Propylene by Gas Chromatography ~ This standard is issued under the fixed designation D 5303; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (~) indicates an editorial change since the last revision or rcapproval,

propylene. COS is detected with a flame photometric detector. 3.3 Calibration data, based on peak areas, are obtained using a known gas standard blend of COS in the range expected for the sample. The COS peak area in the sample is measured and the concentration of COS calculated. 3.4 The COS gas standard blend is assayed prior to use for calibration.

1, Scope I. 1 This test method covers the determination of traces of carbonyl sulfide (COS) in propylene. It is applicable to COS concentrations from 0.5 to 4.0 mg/kg (parts per million by mass). See Note 1.

NOTE I--The lower limit of this test method is believed to be below 0.1 mg/kg, depending on sample size and sensitivity of the instrumentation being used. However, the cooperative testing program was conducted in the 0.5 to 4.0 range due to limitations in preparing commercial test mixtures.

4. Significance and Use 4.1 In processes producing propylene, COS usually remains with the C 3 hydrocarbons and must be removed, since it affects product quality. COS acts as a poison to commercial polymerization catalysts, resulting in deactivation and costly process downtime. 4.2 Accurate gas chromatographic determination of trace COS in propylene involves unique analytical problems because of the chemical nature o f COS and idiosyncracies of trace level analyses. These problems result from the reactive and absorptive nature of COS, the low concentration levels being measured, the type of detector needed, and the interferences from the propylene sample matrix. This test method addresses these analytical problems and ways to properly handle them to assure accurate and precise analyses. 4.3 This test method provides a basis for agreement between two laboratories when the determination of trace COS in propylene is important. The test method permits several calibration techniques. For best agreement between two labs, it is recommended that they use the same calibration technique.

1.2 The values stated in SI units are to be regarded as the standard. 1.3 This standard does not purport to address all of the

safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Specific precautionary statements are given in Notes 3 and 4 and Section 8. . Referenced Documents

2. l ASTM Standards: D 2163 Method for Analysis of Liquefied Petroleum (LP) Gases and Propylene Concentrates by Gas Chromatography 2 D 3609 Practice for Calibration Techniques using Permeation Tubes 3 D4468 Test Method for Total Sulfur in Gaseous Fuels by Hydrogenolysis and Rateometric Coiorimetry4 E 260 Practice for General Gas Chromatography Procedures -s E 840 Practice for Using Flame Photometric Detectors in Gas Chromatography 5

5. Interferences 5.1 Hydrogen sulfide (H2S) or sulfur dioxide (SO2) can be present in the propylene and must be separated from COS. (See Note 2.)

3. Summary of Test Method 3.1 A procedure is given for removing a sample from the sample cylinder, separating COS from propylene, detecting COS, calibrating the detector, quantitating COS content in the sample, and assaying the gas standard. General comments and recommended techniques are given. 3.2 A relatively large volume of sample is injected into a gas chromatograph having a single packed column, operated isothermally at 10 to 50"C, that separates COS from

Note 2--H2S and SO2 are separated from COS with the Carbopack BHT 100 columns or with the Chromosil 300 column.

6. Apparatus 6.1 Gas Chromatograph--Any gas chromatograph (GC) equipped with a flame photometric detector/electrometer system (FPD), as described in 6.2, may be used. A GC/FPD equipped with an output signal linearizer is also permitted. 6.2 Detector System, flame photometric detector, either single or dual burner design. Noise level must be no more than one recorder chart division (see 6.5). The signal for COS must be at least twice the noise level at the 0.1 mg/kg level. A discussion of this detector is presented in Practice E 840. The electrometer used with the detector must have a sensitivity of

J This test method is under the jurisdiction of ASTM Committee 1)-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee 1)02.1)0.02 on C3 Test Methods. Current edition approved Oct. 15, 1992. Published December 1992. 2 Annual Book of ASTM Standards, Vol 05.02. 3 Annual Book of ASTM Standards, Vol I 1.03. 4 Annual Book ofASTM Standardv, Vol 15.05. s Ammal Ilook o/,,ISTM Stamlards, Vol 14.01.

864

~

D 5303

10-'2 A full scale on a I mV recorder to achieve optimum detectability at lowest levels. 6.3 Column--Any column that will effect the complete separation of COS from propylene and other compounds normally present in propylene concentrates, and that is st, lliciently inert to preclude the loss of COS, may be used. Columns that meet these criteria, and that were used in the cooperative study for this test method, are listed in Table 1. 6.4 Sample Inlet System~Any gas sampling valve or gas tight syringe that will permit introduction of up to 5.0 mL to the column, and that will not cause any loss of COS, is suitable. 6.5 Recorder~Any strip chart recorder with a full scale range of 1 mV, a maximum full scale balance time of 2 s, and a minimum chart speed of 0.5 cm/s, may be used. 6.6 Data Handling System~Any commercially available GC integrator or GC computer system capable of accurately integrating the area (uVs) of the COS peak is satisfactory. Data systems that will linearize the logarithmic output of the FPD are also satisfactory. 6.7 Sample Cylinders, 300 mL capacity or larger, fluorocarbon lined stainless steel, Type DOT 3E, 12409 kPa (1800 psi) working pressure.

Nolt 4. ~ arning--Flammablc! Health Hazard.

7.9 Nitrogen or helittm. 99.999 % rain. 7.10 77"E-/htorocarbon septa and a/ttminttm seals ,td,"

vials'.

8. ! lazards 8.1 Carbonyl sullide is toxic and narcotic in high concentrations, and upon decomposition can liberate hydrogen sulfide. Exposure to dangerous concentrations of COS is most likely when handling the pure component for preparation of standard blends for assaying the COS calibration gas standards.

9. Sampling 9.1 Supply samples to the laboratory in high pressure cylinders coated internally with TFE-fluorocarbon, or otherwise specially treated to reduce or eliminate loss of COS due to reaction with the cylinder walls. 9.2 The sample cylinder and contents should be at room temperature prior to sampling to the chromatograph. Test samples as soon as possible after receipt. NOTE 5mCooperative studies indicate that the measured value for

COS will decrease with time.

7. Reagents and Materials 7.1 Air, zero grade. 7.2 Carbonyl sulfide (COS), lecture bottle, 97.5 % rain. Note 3: Warning--Toxic! See Section 8, Hazards. 7.3 Gas Calibration Blends, 1 to 10 mg/kg COS in either nitrogen, argon, propylene or a propylene/argon mixture. They can be obtained from any commercial supplier or prepared as shown in Appendix X 1 or Test Method D 4468. 7.4 Gas Sampling Syringe, O.1, 1.0, and 5.0 mL. 7.5 Gas Sampling Valve and Sample Loops, fluorocarbon or 316 stainless steel. See Footnote B of Table 1. 7.6 Glass Vials, 125 cm. 7.7 ll),th'ogen, pure grade, 99.9 %. 7.8 lsooctane (2,2,4-trimethylpentane), sulfur free, minimum purity 99 mol %. TABLE 1

9.3 Place the sample cylinder in a vertical position and use either of the following two techniques to obtain a vaporized sample from the container for introduction into the GC. 9.3.1 Connect the sample cylinder to the sampling valve on the chromatograph, using a minimum length of 316 ss tubing, so that sample is withdrawn from the bottom of the cylinder. Adjust the flow rate from the sample cylinder so that complete vaporization of the liquid occurs at the cylinder valve. A flow rate of 5 to 10 bubbles/s through a water bubbler placed at the sample vent is sufficient (see Note 6). Turn the sampling valve to the "flush" position and flush for approximately 15 s. Shut offthe cylinder valve and allow the pressure to drop to atmospheric. NOTE 6RIf the flow rate is too fast, warming of the valve can be required to avoid freezingand to ensure complete vaporization of the sample.

Suitable GC Columns and Temperatures A

Column Number

Size,m x mm

Tubing B Type

Packing and Oven Temperature, oC

1 2

0.9 x 3.78 1.4 × 3.78

SS TFE c

3 4 5 6

1.8 x 1.8 x 2.4 x 2.4 x 2.8 x

3.78 3.78 3.78 3.78 3.78

TFE TFE TFE SS TFE

7

3.6 x 3.78

TFE

8 9

4.3 x 3.78 6.1 x 3.78

TFE TFE

Porapak R, 80/100 Mesh; 47 Carbopack BHT 100, 40/60 Mesh; 25,40 E Carbopack BHT 100; 25,30 ~ Porapak Q, AW, 50/80 Mesh (Above in Series); 74 Carbopack BHT 100; 47 Carbopack BHT 100, 40/60 Mesh; 50 Carbopeck BHT 100, 40/60 Mesh; 50 Chromosil 300; 50 ° Hayes Sep Q, 80/100 Mesh; 65

9.3.2 Alternatively, obtain a sample with a gas tight syringe. A convenient way to do this is to'use flexible plastic tubing to connect the bottom of the sample cylinder to the water bubbler and then to pierce the tubing with the syringe needle after flow is established.

10. Preparation of Apparatus 10.1 Install in the GC according to the manufacturer's instructions any of the columns that meet the criteria in 6.3. Set the instrument conditions as follows: 10.1.1 Oven Temperature, as determined by column used, 10.1.2 Detector, 100 to 2000C, and 10.1.3 Injector, 100 to 1500C.

A These columns have been tested cooperatively and found suitable for use with this test method. a 316 SS Tubing for columns or connection of sample cylinder to sampling system can be TFE lined internally to improve on system stability. This tubing is commercially available from chromatography vendors. c TFE~Homopolymer of tetrafluoroethylene. o Propyne (methyl acetylene) can interfere with COS using this column. E Identical columns used by different labs at different temperatures.

11. Calibration I1.1 Three methods of calibration are permitted. These are the Standard Sample Method (see I 1.2), the Permeation Tube Method (see 11.3) and Blend Preparation Techniques (see 11.4). Obtain a calibration standard according to one of these methods, which are described below. Then follow the 865

~

D 5303

procedure in 12.1 through 12.4 and the calculations described in I 1.5. l l.2 Standard Sample Method--Purchase a certified commercial calibration sample of l0 mg/kg COS in propylene, or other suitable matrix gas such as nitrogen, argon, or a propylene/argon mixture. If an inert gas is chosen, the user must ensure that the column is actually effecting a separation of COS and propylene. Establish a calibration curve with the standard sample using either a gas syringe or different, size sample loops. For example, assume the normal sample size for the analysis is 1.0 mL and the calibration range to be established is 0.5 to 5 mg/kg of COS. Establish a calibration curve by injecting the volumes of a l0 mg/kg standard sample shown in the first column of the table below. The equivalent concentration of COS in a 1.0 mL sample would be that shown in the second column: Standard Sample

Equivalent Concentration, COS mg/kg

0.05 0.10 0.20 0.30 0.40 0.50

0.5 1.0 2.0 3.0 4.0 5.0'

11.3 Permeation Tube Method--Refer to Practice D 3609 for directions on using permeation tubes. 11.4 Blend Preparation Techniques--Techniques for the preparation and assay verification of calibration blends in the laboratory are described in Appendixes X I and X2. Also, a technique using a moving piston graduated cylinder apparatus, that is described in the calibration section of Test Method D 4468, can be used. However, some laboratories have found that the preparation of such blends is far from easy, and successful efforts require considerable knowledge and experience. 11.5 Quanlilalion--The flame photometric detector responds logarithmically to the mass of the sulfur present in the flame. Some GC/FPD systems are programmed to linearize logarithmic data, and with such systems the output can be correlated directly with the COS concentration, using a single point calibration. Calculate a calibration factor, F, in accordance with Eq (l) below: F= C/A (I) where: F = calibration factor, C = concentration, mg/kg, of COS in this test method, and A = area (uVs) of the COS peak in this test method. F will be used in Eq (2) in 13.1. I. However, if a linearizer is not used, or if the data system does not have a provision to handle logarithmic output, use the method in I 1.5.1 or the alternate in I 1.5.2, below: l l.5. I Calculate the nanogram (ng) amounts of sulfur, as described in Appendix X3, for each injection ofthe standard, and plot the natural logarithm (In) of peak area versus the l n(ng) of sulfur, as illustrated in Table 2 and Fig. I. The plot should be a straight line. 11.5.2 Alternatively, plot the concentration of COS in mg/kg versus the square root of the peak area. This plot should also be a straight line.

TABLE 2 E x a m p l e of COS Calibration Data A NOTE--COS Standard (3.00 ng S/cm3). Amount of Standard Injected (ng S)

(peak area units)

3.0 3.0 25 25 20 2.0 1.5 1.5 1.0 1.0 0.5 0.5

90 9.0 75 75 6.0 6.0 45 4.5 3.0 3.0 1.5 1.5

53 51 39 38 25 23 18 16 10 9 3 4

A Correlation coefficient of fit (r) = 0.9952: m = slope (detector response factor) = 1.4920, y = peak area units, z = nanograms of sulfur as COS injected, and b = intercept = 1.8394. a Calibrationequation:y = b z " .

syringe, as described in 9.3, inject the sample into the gas chromatograph. 12.2 Record the response of the FPD on the strip chart recorder as the COS elutes from the column. 12.3 Alternatively, obtain the computer or integrator output of COS retention time and peak area. 12.4 Obtain duplicate chromatograms of the sample. Fig. 2 illustrates a typical analysis using a Carbopack BHT-100 column. 13. Calculation 13.1 Depending on the method of calibration used (see Section I1), determine the concentration of COS in the sample.

4.0

~'~ 3.0 m

>. 2.0 2

1.0

l

1.0

12. Procedure 12.1 Using either the gas sampling valve or a gas tight

In z (ng FIG. 1

866

ya

Amount of Standard Injected (cm3)

t 2.0

sulfur)

COS Calibration Plot

!

3.0

@ D5303 Nt)rJ: 7--1fa calibration method is used that gives results in cm a/m 3 (ppm by volume), such as that in Test Method D 4468, then results must

Propylene

be convcrtcd to mg/kg. Use the followingformula to do this: COS, mg/kg -- B x MI/M2 (3) where: B =COS, cm3/m 3, MI =mole weight, COS = 60.1, and M2 =mole weight, propylene = 42.1. 14. Precision and Bias 14.1 PrecisionwThe precision of this test as determined by the statistical examination of interlaboratory test results is as follows:6 14.1.1 Repeatabilio,IThe difference between successive results obtained by the same operator with the same apparatus under constant operating conditions on identical test material would, in the long run, in the normal and correct operation of the test method exceed the following values only in one case in twenty (see table in 14.1.2): repeatability = O.15 X

~(o.9 8

6

~91kq)

4

Minutes NoTE--CarbopackBHT-100column. FIG. 2 Chromatogram of COS in Propylene

13.1.1 If the system provides a linearized output, determine COS concentration according to Eq (2), below: COS, mg/kg = F × S

where: X = the average of two results in mg/kg. 14.1.2 ReproducibilitywThe difference between two single and independent results obtained by different operators working in different laboratories on identical test material would, in the long run, exceed the following values only in one case in twenty (see table below): reprodm'ibility = 1.0 X where: X = the avcrage of two results in mg/kg. Average Value mg/kg

(2)

where: F = calibration factor from Eq (l), and S = area (uVs) of the COS peak from the sample. 13.1.2 If a calibration curve of I n peak area versus 1n(ng) sulfur was used (see l l.5.1), then determine the concentration of COS as shown in Appendix X I. 13.1.3 If a calibration curve of concentration versus log peak area was used (see 11.5.2), then determine the COS concentration as follows: 13.1.3. l Calculate the log of the area of the COS peak of sample. 13.1.3.2 Take the COS concentration directly from the curve using the log value from 13.1.3.1.

0.5 1.0 2.0 3.0 4.0

Repcatabdily mg/kg 0.11 0.15 0.21 0.26 0.30

Rcproducibdity mg/kg 0.7 1.0 1.4 1.7 2.0

14.2 B i a s I S i n c e there is no acceptable reference material suitable for determining the bias for the procedure in this test method (D 5303) for measuring carbonyl sulfide, bias has not been determined. 15. Keywords 15.1 carbonyl sulfide; flame photometric detector; gas chromatography; propylene ~Suppofting data have been filed at ASTM Headquarters. Request RR:D 02-1298.

867

~

D 5303

ANNEXES (Nonmandatory Information)

X1. PREPARATION OF A LIQUID ASSAY STANDARD

X 1.1 Preparation Example: XI.I.1 Pipet 100 mL isooctane (iC,) into the sample bottle and seal it with a septum and cap. Inject through the septum 0.5 mL COS. This standard contains 6.3 rig S/IaL, 'as calculated below: X I.I.2 Use the ideal gas law in the form PmVI/T m = P2V~'T2. Assume ambient conditions: 30"C, 740 mm Hg. Weight of COS/iCr solution = 69.2 g:

v~=

PIVtT~=760m m H g P2Tj

740 m m H g

60 g COS 1 mol x x 0.5 mL COS mol 25 533 mL

.'.

22400 m L x

= !.175 x 10-3 g COS ----0.63 x 10-3 gS 0.63x 10-3gS_9.1 × 10-6gS 69.2 g g solution m

9.1 x 10-6gSxO.6919x 10-3giCr_6.30x 1 0 - g g s 6.3nS/laL g solution laL iC~ laL = XI.I.3 The sulfur concentration in the liquid standard may be cross-checked by microcoulometry, that determines total sulfur content.

303 K x

mol

= 25 533 mL/mol 273 K

X2. PREPARATION OF CALIBRATION GAS BLENDS X2.3 Procedure

X2.1 Apparatus

X2.3.1 Cap a 980 mL bottle containing a stirring bar, and purge with propylene for 20 rain at a rate of 500 mL/min. X2.3.2 Pressurize to 10 prig with propylene. X2.3.3 Place on stirrer, transfer (by use of gas lock syringe) 1 mL of neat COS. Allow to stir for 5 rain. X2.3.4 Prepare a second bottle in the same manner as in X2.3.1 to X2.3.3, except that instead ofCOS a 1 mL portion of the first blend is added by means of a syringe. This yields a standard gas blend of 0.527 mg/kg. X2.3.5 Blends of varying concentrations of COS in propylene can be made in the same manner, by varying the amount of the primary blend used in making the final calibration blend.

X2.1.1 Bottles, heavy wall, "soda pop" type, 980 mL. X2.1.2 Crimp Caps, drilled and fitted with a septum. X2.1.3 Bottle Capper. X2.1.4 Manometer. X2.1.5 Magnetic Stirrer and Stirring Bars. X2.1.6 Gas Lock Syringe. X2.2 Reagents

X2.2.1 Carbonyl sulfide. X2.2.2 Hydrogen sulfide. X2.2.3 Propylene, reagent grade.

X3. CALCULATION FOR SULFUR C O N T E N T OF STANDARD X3.1 Sample Calculation--For ng S/mL as COS: assume the calibration equation is as follows:

Use ideal gas law: where:

PV = nRT = (grams/MW) x R T

y = 1.8394 z

P V

= pressure in atmospheres, = volume in mL, M W = molecular weight of propylene in g/mol, R = gas constant = 82.05 mL atm/" K tool, T = temperature in * Kelvin = 303, and PV (MW). grams = RT

for range o f y values 3 to 53 (refer to Table 2), and 5 mL of a propylene sample gives a COS peak area of 29 units. Therefore: 29 = 1.8394 z where: z = 6.35 ng S/5 mL = 1.27 ng S/mL of sample. X3.2 This corresponds to 1.44 mg/kg (w/w) COS as calculated below:

(740 mm Hg) (1 mL) (42.1 g/tool) 760 = !.65 x 10-3g (82.05 mL atm) K moi (303 K)

Basis: pure propylene, mol wt. = 42.1 g/tool ambient condition: 740 mm Hg, 30" C sulfitr analysis: 1.27 ng S/mL = 2.38 ng COS/mL wanted: mass of I mL propylene

mg/kg COS --

868

2.38 x 10-9 RCOS 1.65 x 10-3g

--- 1.44 x 10-6x I06= 1.44

o 5303

Thf~American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly adwsed that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reepproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend, ff you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103.

869

(~

Designation:D 5307 - 97

Standard Test Method for Determination of Boiling Range Distribution of Crude Petroleum by Gas Chromatography 1 This standard is issued under the fixed designation D 5307; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (~) indicates an editorial change since the last revision or rcapproval.

1. Scope I.I This test method covers the determination of the boiling range distribution of water-free crude petroleum through 538"C (1000*F). Material boiling above 538*(2 is reported as residue. This test method is applicable to whole crude samples, that can be solubilized in a solvent to permit sampling by means of a microsyringe. 1.2 The values stated in SI units are to be regarded as the standard. The values stated in inch-pound units are for information only. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Specific precautionary statements are given in Notes 1, 2, 3, 4, and 5.

2. Referenced Documents 2.1 A S T M Standards: D 2892 Test Method for Distllafion of Crude Petroleum (15-Theoretical Plate Column) 2 D4057 Practice for Manual Sampling of Petroleum and Petroleum Products 2 3. Terminology 3.1 Definition of Terms Specific to This Standard: 3.1.1 area slice, n--the area, resulting from the integration of the chromatographic detector signal, within a specified retention time interval. 3.1.1.1 Discussion--In area slice mode (see 6.2.2), peak detection parameters are bypassed and the detector signal integral is recorded as area slices of consecutive, fixed duration time intervals. 3.1.2 corrected area slice, n--an area slice corrected for baseline drift, by subtraction of the exactly corresponding area slice in a previously recorded blank (nonsample) analysis; correction for signal offset may also be required. 3.1.3 cumulative correctedarea, n--the accumulated sum of corrected area slices from the beginning of the analysis through a given retention time, ignoring any nonsample area (for example, solvent). 3.1.4 initial boiling point (IBP), n--the temperature (corI This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.04.0H on Chromatographic Methods. Current edition approved June 10, 1997. Published October 1997. Originally published as D 5307 - 92. Last previous edition D 5307 - 92. 2 Annual Book of A S T M Standards, Vol 05.02.

responding to the retention time) at which a cumulative corrected area count equal to 0.5 % of the theoretical total area is obtained. 3.1.5 residue, RES n--the amount of sample boiling above 538"C (lOO0*F). 3.1.6 theoretical total area, T n--the area that would have been obtained if the entire sample had been eluted from the column. 3.1.6.1 Discussion--This is determined in 12.3. 3.2 Abbreviations: 3.2.1 A common abbreviation of hydrocarbon compounds is to designate the number of carbon atoms in the compound. A prefLX is used to indicate the carbon chain form, while a subscripted suffix denotes the number of carbon atoms (for example, normal decane ffi n-Cio; isotetradecane ffi i-CI4). 4. Summary of Test Method 4.1 The crude oil sample is diluted with carbon disulfide, and the resulting solution is injected into a gas chromatographic column that separates hydrocarbons in boiling point order. The column temperature is raised at a reproducible, linear rate, and the area under the chromatogram is recorded throughout the run. Boiling points are assigned to the time axis by comparison to a calibration curve obtained under the same chromatographic conditions by running a mixture of n-paraffins of known boiling point through a temperature of 538°C (1000°F). The amount of sample boiling above 5380C is estimated by means of a second analysis of the crude oil to which an internal standard has been added. From these data, the boiling range distribution of the water-free sample is calculated.

5. Significance and Use 5.1 The determination of the boiling range distribution is an essential requirement in crude oil assay. This information can be used to estimate refinery yields and, along with other information, to evaluate the economics of using one particular crude as opposed to another. 5.2 Results obtained by this test method are equivalent to those obtained from Test Method D 2892. (See Appendix Xl.) 5.3 This test method is faster than Test Method D 2892 and can be used when only small volumes of samples are available. Also, this test method gives results up to 538°C while Test Method D 2892 is limited to 400°C. 6. Apparatus 6.1 Gas Chromatograph--Any gas chromatograph may be used that has the capabilities described below and meets

870

o saoz the performance requirements in Section 10. 6.1.1 Detector~This test method is limited to the use of the flame ionization detector (FID). The detector must be capable of operating continuously at a temperature equal to or greater than the maximum column temperature employed, and it must be connected to the column so as to avoid cold spots. 6.1.2 Column Temperature Programmer--The chromatograph must be capable of reproducible, linear programmed temperature operation over a range sufficient to establish a retention time of at least 1 min for the IBP and to elute compounds with boiling points of 538"C (1000*F) before the end of the temperature ramp. 6.1.3 Cryogenic Column Oven--If the IBP of the crude oil is below 90"C (194"F), an initial column temperature below ambient will be required. This necessitates a cryogenic cooling option on the gas chromatograph. Typical initial column temperatures are listed in Table 1. 6.1.4 Sample Inlet System--Either of the following two types of sample inlet systems may be used. 6.1.4.1 Flash Vaporization--A vaporizing sample inlet system must be capable of operating continuously at a temperature equivalent to the maximum column temperature employed. The sample inlet system also must be connected to the chromatographic column so as to avoid any cold spots. 6.1.4.20n-ColumnwCapable of introducing a liquid sample directly onto the head of the column. Means must be provided for programming the entire column, including the point of sample introduction, up to the maximum column temperature employed. 6.1.5 Flow Controller--The chromatograph must be equipped with a flow controller capable of maintaining cartier gas flow constant to + 1% over the full operating temperature range of the column. The inlet pressure of the carrier gas, supplied to the chromatograph, must be sufficiently high to compensate for the increase of backpressure in the column as the temperature is programmed upward. An inlet pressure of 550 kPa gage (80 psig) has been found satisfactory with the columns described in Table 1. 6.2 Data Retrieval System: 6.2.1 Recorder--A 0-1 mV range recording potentiometer or equivalent, with a full-scale response time of 2 s or TABLE 1

7. Reagents and Materials

7.1 Purity of Reagents--Reagent-grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society where such specifications are available. 3 Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination. 7.2 AirmZero grade (hydrocarbon free) for use with the FID. (WarningmSee Note 1.) NOTE 1: W a r n i n g - - A i r is a compressed gas under high pressure a n d

supports combustion. 7.3 Calcium Chloride, Anhydrous (CaCI2). 7.4 Calibration Mixture--A mixture of n-paraffins dissolved in carbon disulfide (Warning--see Note 2) covering the boiling range of the sample through 538"C (1000*F). At least one compound in the mixture must have a boiling point equal to or lower than the IBP of the sample. Methane, ethane, propane, or butane can be added to the calibration mixture, if necessary, by injecting about 1 mL of the pure gaseous compound into a septum-capped, sealed vial containing the rest of the calibration mixture, using a gas syringe. If n-paraffin peaks can be unambiguously identified in the sample chromatogram, their retention times can be used for calibration.

Typical Operating Conditions 1

2

3

Column length, mm (in.) Column diameter, mm (in.) Liquid phase

457 (18) 610 (24) 3.17 (l/a) 3.17 (1/8) 10 % UCW-982 3 ~, OV-1

457 (18) 3.17 0/n) 10 ~, SE-30

Support material

Chromosorb pA.Aw

Chromosorb WA.H P

Chromosorb pA.AW

-30

-30

-40

380

350

360

t0 N2 25 400 380

10 He 20 380 375

10 N2 28 400 400

Column temperature initial value, *C Column temperature final value, *C Programming rate, *C/rain Carder gas type Carrier gas flow, mL/min Detecter temperature, *C Injection port temperature, *C

less may be used for graphic presentation of the FID signal. 6.2.2 Integrator~Electronic integrator or computer-based chromatography data system must be used for detector signal integration and accumulation. The integrator/computer system must have normal chromatographic software for measuring retention time and areas of eluting peaks (peak detection mode). In addition, the system must be capable of converting the continuously integrated detector signal into area slices representing contiguous fixed duration time intervals (area slice mode). The recommended time interval is 1 s. No time interval shall be greater than 12 s. The system must be capable of subtracting the area slice of a blank run from the corresponding area slice of a sample run. Alternatively, the baseline chromatogram can be substracted from the sample chromatogram and the net resulting chromatogram can be processed in the slice mode. A computer program that performs the slice calculation as a post-run calculation is also used. 6.3 Column--Any gas chromatographic column that provides separation in order of boiling points and meets the performance requirements of Section l0 can be used. Columns and conditions, which have been used successfully, are shown in Table 1. 6.4 MicrosyringewA 5 or l0 IxL syringe is used for sample introduction. The use of an automated liquid sampling device is highly recommended.

3 Reagent Chemicals, American Chemical Society Specifications, American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed by the American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), RockviUe, MD.

A See Footnote 5.

871

q~ D 5307 7.5 Carbon Disulfide (CS2)--Carbon disulfide (99 % minimum purity) is used as a viscosity reducing solvent because it is miscible with crude oils and has only a slight response with the FID. (Warning--See Note 2.) NOTE 2: Warning--Carbon disulfide is extremely volatile, flammable, and toxic.

7.6 Carrier Gas--Nitrogen or helium of high purity that has been dried over molecular sieves or similar suitable drying agents. (Warning--See Note 3.) NOTE 3: Warning--Helium and nitrogen are compressed gases under high pressure.

7.7 Column Resolution Test Mixture--A mixture of 1% each of n-C~6 and n-C~s paraffin in a suitable solvent, such as n-octane, for use in testing the column resolution. (Warning--See Note 4.) NOTE 4: Warning--n-Octaneis flammableand harmfulif inhaled.

7.8 Detector Response Test Mixture--An accurately weighed mixture of approximately equal masses of at least six n-paraffins covering the carbon number range from 10 to 44. Dissolve one part of this mixture with approximately five parts of CS2 (or sufficient CS2 to ensure a stable solution at room temperature). 7.9 Hydrogen--Hydrogen of high quality (hydrocarbon free) is used as fuel gas for the HD. (Warning--See Note 5.) NOTE 5: Warning--Hydrogenis an extremelyflammablegas under high pressure.

7.10 Internal Standard--A mixture of approximately equal amounts of four n-paraffins, n-C]4 through n-C~7. Concentrations of the individual components need not be known but must be within the linear range of the detector/ electronics system used. 7.11 Liquid Phase--A nonreactive, nonpolar liquid or gum of low volatility. Silicone gum rubbers are typically used. In general, liquid phase loadings of 3 to 10 % have been found most satisfactory. 7.12 Solid Support--A diatomaceous earth or equivalent nonreactive particulate material. Typical particle size ranges are 60/80 or 80/100 mesh. 8. Sampling

8. I Obtain samples for analysis by this test method in accordance with instructions given in Practice D 4057. 8.1.1 Ensure that samples are received in sealed containers and show no evidence of leakage. 9. Preparation of Apparatus

9.1 Column Preparation--Any satisfactory method used in the practice of the art, that will produce a column meeting the requirements of Section 10, may be used. 9.2 Column Conditioning--The column must be conditioned at the maximum operating temperature to reduce baseline shifts due to bleeding of the column substrate. The column can be conditioned rapidly and effectively using the following procedure:

872

9.2.1 Connect the column to the inlet system but leave the detector end free. 9.2.2 Purge the column at ambient temperature with carrier gas. 9.2.3 Turn off the carrier gas and allow the column to depressurize completely. 9.2.4 Seal off the open end of the column with an appropriate fitting. 9.2.5 Raise the column to the maximum operating temperature and hold at this temperature 4 to 6 h, with no flow through the column. 9.2.6 Cool the column to ambient temperature. 9.2.7 Remove the cap from the column and connect the column to the detector. Re-establish carrier flow. 9.2.8 Program the column temperature to the maximum several times with normal carrier gas flow rate. 9.3 An alternate method of column conditioning, that has been found effective with columns with an initial loading of 5 % liquid phase, consists of purging the column (disconnected from the detector) with normal carrier gas flow rate for 12 to 16 h, while holding the column at the maximum operating temperature. 9.4 Chromatograph--Place the chromatograph in service in accordance with the manufacturer's instructions. Typical operating conditions are shown in Table 1. 9.4.1 Excessively low initial column temperature must be avoided to ensure that the column phase functions as gas-liquid chromatographic column. Consult the stationary phase manufacturer's literature for minimum operating temperature. The initial temperature of the column should be only low enough to obtain a calibration curve meeting the specifications under 6.1.3. 9.4.2 Silica from combustion of column material deposits on the FID parts. This deposit must be removed regularly, by brushing, because it changes response characteristics of the detector. 9.4.3 Silica deposits also can plug the end of the flame jet. This problem can be alleviated greatly by utilizing a flame jet with an inside diameter of at least 0.76 mm (0.030 in.) 10. System Performance

10.1 Resolution--Analyze an aliquot of the column resolution test mixture (see 7.7) utilizing identical conditions as used in the analysis of samples. The resolution of n-C~6 and n-C~s n-paraffin peaks must be between three and ten when calculated in accordance with the following equation (refer to Fig. 1): R = [2(t2 - tl)]/[l.699(F2 + YI)] (1) where: R = resolution, tl ffi time for the n-Ct6 peak apex, in seconds, t2 ffi time for the n-C~s peak apex, in seconds, Y1 = peak width, at half height, of n-C~6, in seconds, and Y2 = peak width, at half height, of n-C~s, in seconds. 10.2 Retention Time Repeatability--The system must be sufficiently repeatable, when testing with the calibration mixture, to obtain retention time repeatability (maximum difference between duplicate runs) of 6 s or less for each calibration peak.

(~

D 5307

columns and detectors. In actual practice, the best compensation can be obtained by directly subtracting the area profile of the blank run derived from a single column. NOTE 7--Some commercially available gas chromatographs have the capability to make baseline corrections (from a stored blank analysis) directly on the detector signal. Further correction of area slices may not be required with such systems. However, if an electronic offset is added to the signal after baseline compensation, additional area slicecorrection may be required in the form of offset subtraction. Consult the specific instrumentation instructions to determine if an offset is applied to the

t2, sec I

tip s e c

Y1, sec Hexadecane

sec

I

Octadecane

signal.

FIG. 1 Column Resolution Parameters

10.3 System Performance Check--Analyze the detector response test mixture (see 7.8) utilizing identical conditions as used in the analysis of samples. Calculate response factors relative to n-decane as follows:

Fn = (Cn/A,)/(CIo/Aao) (2) where: A, = area of that n-paraffin peak, Alo = area of n-decane peak, C, = concentration of that n-paraffin in the mixture, Cto = concentration of n-decane in the mixture, and F, = response factor relative to n-decane. 10.3.1 The response factor (Fn) of each n-paraffin must not deviate from unity by more than 10 %. 10.3.2 With some chromatographs, response factors for higher boiling n-paraffins (n-C2o to n-C44) have been observed to change after several crude oil samples have been analyzed. Check the stability of the system by repeating the performance test after analyzing ten samples. If the system still meets the performance specified (see 10.3.1), it is not necessary to repeat this check after subsequent analyses. However, it is good practice to repeat the performance test if detector components are changed. 11. Procedure 11.1 Baseline Compensation Analysis--To compensate for baseline drift and signal offset, subtract an area slice profile of a blank run from the sample run to obtain corrected area slices. This profile is obtained as follows: 11.1.1 After conditions have been set to meet perfo.cmance requirements, program the column oven temperature upward to the maximum temperature to be used and hold for at least ten minutes. 11.1.2 Following a rigorously standardized schedule, cool the column to the selected starting temperature, and allow it to equilibrate at this temperature for at least 3 min. At the exact time set by the schedule, without injecting a sample, start the column temperature program. 11.1.3 Acquire the data in area slice mode (see 6.2.2), recording the area slices for each time interval from the start of the run until the end of the run. It is essential that all measurements be on the same time basis for the blank and sample runs. 11.1.4 Perform a blank analysis at least once each day analyses are performed. NOTE 6--A completely satisfactory baseline is difficult to obtain when compensation for column bleed is attempted with matched dual

11.2 Retention Time Versus Boiling Point Calibration: 11.2.1 Using the same conditions as for the blank run, and following the same rigorously standardized schedule (see 11.1), inject an appropriate aliquot of the calibration mixture (see 7.4) into the chromatograph. Record the data in such a manner that retention times and areas for each component are obtained (peak detection mode). 11.2.1.1 The volume of the calibration mixture injected must be selected to avoid distortion of any component peak shapes caused by overloading the sample capacity of the column. Distorted peaks will result in displacement of peak apexes (that is, erroneous retention times) and hence errors in boiling point determination. The column liquid phase loading has a direct bearing on acceptable sample size. 11.2.2 Plot the retention time of each peak versus the corresponding boiling point for that component, as shown in Fig. 2. Boiling points of n-paraffins are listed in Table 2. Tabulate these same data and save for later calculations. 11.2.3 The calibration curve should be essentially a linear plot of boiling point versus retention time. Since it is not practical to operate the column so as to completely eliminate curvature at the lower end of the curve, the calibration mixture must contain at least one n.paraffin with a boiling point equal to or lower than the IBP of the sample. Extrapolation of the curve at the upper end (to 538"C) is 600

1100

1000 500 900 800 400 700 600 D.

300

a.

500

=

z=

200

400 300

100 200 100 0 -100

I 5

[ 10

J 15

[ 20

I 25

I 30

Retention Time, Minutes

FIG. 2 Typical Calibration Curve

873

0 *.

I 35

-100 40

'6 m

(@) D 5307 TABLE 2

pletely. Use this solution for the crude oil plus internal standard analysis (see 11.4.1). I 1.3.9 In a second vial, dissolve approximately the same amount of dried sample as 11.3.5 with an approximately equal volume of carbon disulfide. Use this solution for the separate crude oil without internal standard analysis (see

Boiling Points of Normal Paraffins A

Carbon Number

BP, *C

BP, *F

Carbon Number

1 2 3 4 5 6 7 8 9 10

-162 -89 -42 0 36 69 98 126 151 174

-259 -128 -44 32 97 156 208 259 304 345

23 24 25 26 27 28 29 30

380 391 402 412 422 431 440 449

716 736 756 774 792 806 825 840

11 12 13 14 15 16 17 18 19 20

196 216 235 254 271 287 302 316 330 344

385 421 455 489 520 549 576 601 626 651

31 32 33 34 35 36 37 38 39 40

458 466 474 481 489 496 503 509 516 522

856 871 865 898 912 925 937 948 961 972

21 22

356 369

674 695

41 42 43 44

528 534 540 545

982 993 1004 1013

BP,

*C

BP, OF

11.4.4).

A See Footnote 7.

more accurate provided extrapolation is not made outside the temperature-programmed portion of the run. However, for best accuracy, calibration points should bracket the boiling range to be measured at both low and high ends. If normal paraffins can be unambiguously identified in the sample, these retention times may be used for calibration. 11.2.4 Perform a boiling point-retention time calibration at least once each day analyses are performed. 11.3 Sample Preparation: 11.3.1 Store very light samples to between 0 and 5"C. Allow the unopened sample to remain within this temperature range for at least 4 h (preferably overnight) before opening. 11.3.2 Shake or stir the sample to ensure homogeneity and pour out a small portion (approximately I00 mL) for subsequent weighing and analysis. I 1.3.3 Heavy, viscous crude may require warming as well as stirring to ensure homogeneity. 11.3.4 Since water is not measured by the FID, a portion of the sample must be dried before the sample can be weighed. Add 2 to 3 g of drying agent, such as anhydrous calcium chloride, to a 50-mL vial and fill the vial about half full with sample. Cap the vial tightly and shake the vial vigorously. Allow the mixture to stand several minutes to allow the drying agent to settle out. By means of a disposable pipette, remove the dried oil layer for sample weighing and analysis. 11.3.5 Weigh at least 10 g of dried sample to the nearest 0. I m g into a 25-mL vial. 11.3.6 Add approximately 1 g of internal standard mixture into the same vial. Determine the weight to the nearest 0.1 mg. 11.3.7 Dilute the mixture with an approximately equal volume of carbon disulfide. 11.3.8 Cap the vial tightly and shake the mixture vigorously for 3 min, or until the mixture is solubilized corn874

11.4 Sample Analysis: 11.4.1 Using the exact conditions that were used in the blank and calibration runs (see 11.1 and 11.2), and following the rigorously defined schedule (see 11.1), inject 1 ~tL of the diluted crude oil plus internal standard mixture into the chromatograph. Record the area slices of each time interval through the end of the run. 11.4.2 Continue the run until the retention time equivalent to a boiling point of 538"C (1000*F) is reached. Stop recording area slices under the chromatogram at this point. 11.4.3 To remove as much as possible of the heavy components remaining on the column, continue heating the column until the FID signal returns to baseline. The column temperature may be increased to speed this process. 11.4.4 Cool the column to the starting temperature. Use identical conditions as used in 11.4.1. Inject 1 ~tL of the crude oil sample without internal standard (see 11.3.9). Record the area slices of each time interval through the end of the run. 11.4.5 The sample plus internal standard analysis (see 11.4.1) and the sample only analysis (see 11.4.4) may be made in either order. 12. Calculation 12.1 Area Corrections: 12.1.1 Obtain corrected area slices for both runs (see 11.4.1 and 11.4.4) by subtracting the corresponding area slice of the blank run profile (see 11.1) from each. (See Note 7.) 12.1.2 Sum the corrected area slices for both runs to obtain the cumulative corrected area at the end of each time interval during the run. 12.2 Theoretical Total Area (Refer to Fig. 3): 12.2.1 Based on retention times from the calibration chromatogram (see 11.2.1), select a retention time that is 5 % less than the retention time of n-Cl4, and another that is 5 % greater than.the retention time of n-C~7. These times define a segment of the chromatogram that includes the internal standard peaks. Record the total area within this segment from the chromatogram of the crude oil plus internal standard mixture (see 11.4. I) (area AIS from Fig. 3(a)). Also record the total area of the same segment from the chromatogram obtained from the crude oil only chromatogram (see I 1.4.4) (area BIS from Fig. 3(b)). 12.2.2 Record the total area of both chromatograms through the retention time equivalent to a boiling point of 5380C (1000°F). 12.2.3 Calculate the mass fraction (I41) of the internal standard in the mixture of sample plus internal standard as follows: W = U(S + I) (3) where: I = mass of internal standard, g, and S = mass of sample, g.

(1~ D 5307 TABLE 3

A • TOTAL ELUTED AREA UP TO 53~eC (I000°FI

z~5oo 21~o

Off

NON-ELUTED SAMPLE AIS = AREA OF CRUDE PLUS INTERNAL STANDARD

lssoo

IBP 5 10 20 30 40 50 60 70 80 85 90 Residue

~-~ 538"C (1000eF")

?500 5500

~TIME

~

155O0 ~Z 13500

,.-°o

s

9500 7500 5500 3500 o

B CRUDE ONLY

FIG. 3

Typical

Chromatograms

12.2.4 Calculate the ratio of areas (r) outside the internal standard segment and through the retention time equivalent to a boiling point of 538"C (1000*F) of the crude oil only chromatogram to the chromatogram from the mixture of internal standard plus crude as follows: r = (B-BIS)/(A-AIS) (4) where: A = total area through 538"C (1000*F) of the crude plus internal standard mixture chromatogram, A I S = total area of the internal standard segment of the crude plus internal standard mixture ehromatogram, B = total area through 538"C (1000*F) of the crude oil only ehromatogram, and B I S = total area of the internal standard segment of the crude oil only ehromatogram. 12.2.5 Calculate the theoretical total area (T) for the crude oil only ehromatogram (Area B + B', Fig. 3(b)) as follows: T = [(AIS x r) - BIS][(I - W ) / W ] (5)

BIS

r

10.6 14.8 11.3 15.4 20.4 24.6 30.3 25.9 39.2 38.8 38.8 44.9 8.1 Mass

13. Report 13.1 Report the following information: 13.1.1 The temperature to the nearest 0.5"C (I°F) at the IBP and at 1% intervals, and 13.1.2 The total residue above 538°C to the nearest 0.1%. 14. Precision and Bias 4

14.1 The precision of this test method as determined by statistical examination of interlaboratory results is as follows: 14.1.1 R e p e a t a b i l i t y - - - T h e difference between two successive test results, obtained by the same operator with the same apparatus under constant operating conditions on identical test material would, in the long run, and in the normal and

where: AIS

Reproducibility, *C

= the mass fraction of internal standard in the mixture of crude sample plus internal standard (see Eq 3). 12.2.6 Calculate the percent residue (RES) above 538"C (1000*F) as follows: RES-- 100- ( B I T x 100) (6) where: B = total area through 538"C (1000*F) of the crude only chromatogram, and T = theoretical total area of the crude oil only chromatogram (see Eq 5). 12.3 Calculation o f B o i l i n g P o i n t Distribution: 12.3.1 Record the time at which the cumulative area at the beginning of the crude only chromatogram is equal to 0.5 % of the theoretical total area (T, From Eq 5). The temperature equivalent to this time is the IBP of the sample. 12.3.2 Multiply the corrected cumulative area at the end of each time interval by 100 and divide by the theoretical total area (T from Eq 5). This gives the percent of sample recovered at the end of each time interval. 12.3.3 Tabulate, in pairs, the cumulative percent recovered and the retention time at the end of each time interval. 12.3.4 Using linear interpolation where necessary, determine the time associated with each percent between 1% and the percent eluted at the time equivalent to 538"C (1000*F). 12.3.5 For each 1% and its associated retention time, determine the corresponding temperature from the table of boiling point-retention time calibration data (see 11.2.2).

538"C 11000= F)

11500

3.7 4.7 6.9 6.8 7.6 9.3 10.6 11.8 17.6 24.8 18.8 20.7 2.6 Mass ~

W

B " TOTAL ELUTED AREA UP TO 538°C (1000eF) B I = AREA CORRESPONDING TO NON-ELUTED SAMPLE SiS = AREA OF SEGMENT WHERE INTERNAL STANDARD ELUTES IN FIGURE 3A

17500

Repeatability, *C

R

A. CRUDE ÷ INTERNAL STANDARD

19500

Repeatability and Reproducibility

= total area of the internal standard segment of the

ehromatogram of the sample plus internal standard mixture, = total area of the internal standard segment of the crude oil only chromatogram, = the ratio of areas outside the internal standard segment through 538"C (1000*F) for both chromatograms (see Eq 4), and

' This precision was obtained from an intcrlaboratory cool~rative study by eight laboratories on five samples. The results of this study have been filed a t ASTM headquarters. Request RR:D02-1295. sAPI Project 44, October 31, 1972.

875

q~ D 5307 distribution can only be defined in terms of a test method. 14.2.1 A rigorous, theoretical definition of the boiling range distribution of crude petroleum is not possible due to the complexity of the mixture as well as the unquantifiable interactions among the components (for example, azeotropic behavior). Any other means used to define the distribution would require the use of a physical process such as a conventional distillation or gas chromatographic characterization. This would therefore result in a method-dependent definition and would not constitute a true value from which bias can be calculated.

correct operation of the test method, exceed the values shown in Table 3 only in 1 case in 20. 14.1.2 Reproducibility--The difference between two single independent results obtained by different operators working in different laboratories on identical test material would, in the long run, and in the normal and correct operation of the test method, exceed the values shown in Table 3 only 1 case in 20. NOTE 8--Samples included in the study had residues ranging from about 3 to 30 %. Samples with residues outside this range may have different precision.

15. Keywords

14.2 BiasmThe procedure in this test method for determining the boiling range distribution of crude petroleum by gas chromatography has no bias because the boiling range

15.1 crude oil; gas chromatography; petroleum; simulated distillation

APPENDIX

(Nonmandatory Information) X1. AGREEMENT WITH CONVENTIONAL DISTILLATION X1.1 Test Method D 2892 is the standard for conventional distillation of crude petroleum. X1.2 Results from this test method have been compared to Test Method D2892 results by several laboratories. 6,7,s.9 Test Method D 2892 has difficulty in establishing

the IBP and light portion of the crude oil, and the distillation must be terminated at a maximum temperature of 400°C to prevent cracking of the sample. X1.3 Footnote 9 is particularly significant because it shows a direct comparison of results by this test method and Test Method D 2892, obtained from round-robin testing of both methods. Data from five laboratories are included.

6 McTa~an, N. G., Glaysher, P., and Harding, A. F., ASTM STP 577, ASTM, 1973, p. 81. 7 Green, L. E., "Chromatograph Gives Boiling Point," Hydrocarbon Processing, May 1976, p. 205. s Worman, J. C., and Green, L. E., Anal. Chem., Vol 37, 1965, p. 1620. 9 Ceballo, C. D. et al. Rev. T~c. INTEVEP, 7(1), 1987, pp. 81-83.

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted In connection with any Item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard Is subject to revision at any time by the responsible technical committee and must be reviewed every five years and ff not revised, either reapproved or withdrawn. Your comments are Invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend, ff you feel that your comments have not received a fair hearing you ,ohould make your views known to the ASTM Committee on Standards, 100 Barr Harbor Drive, West Conshohockon, PA 19428.

876

~fll~ Designation: D 5384 - 95 Standard Test Methods for Chlorine in Used Petroleum Products (Field Test Kit Method) 1 This standard ts issued under the fixed designation D 5384; the number immediately following the designation indicates the year of original adoption or, m the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (~) indicates an editorial change since the last revision or reapproval.

3. Summary of Test Methods 3.1 The oil sample (approximately 0.3 g) is dispersed in a hydrocarbon solvent and reacted with a mixture of metallic sodium catalyzed with naphthalene and diglyme at ambient temperature. This process converts organic halogens to their respective sodium halides. Halides in the treated mixture, including those present prior to the reaction, are then extracted into an aqueous buffer, which is then titrated with mercuric nitrate using diphenyl carbazone as the indicator. The end point of the titration is the formation of the blue-violet mercury diphenylcarbazone complex. 3. I. 1 Preset reagent quantities are used for Method A so that the final result is clearly determined to be either above or below 1000 mg/kg total chlorine. 3.1.2 A fixed concentration titrant of mercuric nitrate in water is used for Method B. A titration is performed on the extracted aqueous sample until the color changes from yellow to blue. At this point, the titration is stopped and the chlorine concentration is determined based on the volume of titrant added.

1. Scope 1.1 These test methods cover the determination of chlorine in used oils, fuels, and related materials, including: crankcase, hydraulic, diesel, lubricating and fuel oils, and kerosene, all containing <25 % (mass/mass) water. 1.1.1 Bromide and iodide are also titrated and reported on a molar basis as chlorine. 1.2 The entire analytical sequence, including sampling, sample pretreatment, chemical reactions, extraction, and quantification, is available in kit form using predispensed and encapsulated reagents. The overall objective is to provide a simple, easy to use procedure, permitting nontechnical personnel to perform a test in or outside of the laboratory environment in under 10 min. The test method also gives information to run the test without a kit. 1.2.1 Method A is preset to provide a greater than or less than result at 1000 mg/kg (ppm) total chlorine to meet regulatory requirements for used oils. 1.2.2 Method B provides results over a range from 200 to 4000 mg/kg total chlorine. 1.3 For both methods, positive bias will result from samples that contain greater than 3 % (mass/mass) total sulfur. While a false negative result will not occur, other analytical methods should be used on high sulfur oils. 1.4 Method B Lower Limit of Quantitation--In the roundrobin study to develop statistics for this method, participants were asked to report results to the nearest 100 mg/kg. The lower limit of quantification could therefore only be determined to be in the range from 870 to 1180 mg/kg 5. 1.5 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. 1.6 This standard does not purport to address all of the

NOTE 1: W a r n i n g - - l n case of accidental breakage onto skin or clothing, wash with large amounts o f water. All the reagents are poisonous and should not be taken internally. NOTE 2: W a r n i n g - - T h e gray ampules contain metallic sodium which is a flammable, water-reactive solid. Reaction with water will generate flammable hydrogen gas. NOTE 3: Precaution--ln addition to other precautions, do not ship kits on passenger aircraft. Kits contain metallic sodium and mercury salts. Used kits will pass the USEPA Toxic Characteristic Leaching Procedure (TCLP) test. Check with your state environmental enforcement office to see if additional disposal regulations may apply. NOTE 4: C a u t i o n - - W h e n the sodium ampule in either kit is crushed,

oils that contain more than 25 % (m/m) water will cause the sample to turn clear to light gray and will build noticeable pressure. Under these circumstances, the results can be biased excessivelylow and should be disregarded. NOTE 5: Warning--In addition to other precautions, take care to ensure that fingers are not cut by glass in the kits. All reagents in pre-packaged kits are contained in crushable glass ampules inside plastic test tubes. Each ampule should be crushed only once to reduce the risk of glass pieces piercing the sides of the tube. Wear safety glasses and gloves throughout the testing procedure.

safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Specific safety statements are given in Section 3.

4. Significance and Use 4.1 Chlorinated compounds can lead to corrosion of equipment and poisoning of the catalyst. Chlorinated compounds also present a health hazard when incompletely combusted. Chlorine content of petroleum products is determined prior to their being recycled.

2. Referenced Document

2.1 ASTM Standard: D4057 Practice for Manual Sampling of Petroleum and Petroleum Products 2

NOTE 6--Federal Regulations mandate that often the chlorine content o f used oil must be determined before recycling.

These test methods are under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and are the direct responsibility of Subcommittee D02.03 on Elemental Analysis. Current edition approved Aug. 15, 1995. Published October 1995. 2 Annual Book t f A S T M Standards, Vol 05.02.

4.2 These test methods can be used to determine when a used petroleum product meets or exceeds requirements for 877

( ~ D 5384 total halogens measured as chloride. It is specifically designed for used oils, permitting on-site testing at remote locations by nontechnical personnel to avoid the delays of laboratory testing.

5. Sampling 5.1 Take samples in accordance with the instructions in Practice D 4057. 5.2 Free water, as a second phase, is to be removed. However, this second phase can be analyzed separately for chloride content by using a method suitable for materials with high water content (see Notes 2 and 4).

into a 1-L volumetric flask and make up to 1 L with Type II water. 7.2.5 For Method B, a 13.7-mmol/L solution of mercuric nitrate. Place 137 mL of stock solution (see 7.2.4) into a 1-L volumetric flask and make up to l L with Type II water. 7.2.6 An aqueous buffer solution containing 6 % (mass/ mass) sodium sulfate, 2.6 % (mass/mass) sodium phosphate and 3.175 % (mass/mass) sulfuric acid (pH 1.5). 8. Procedure (Methods A and B) NOTE 6--Perform the test in a dry area with an ambient temperature greater than 15"C (60*F) and adequate light. In cold weather, a truck cab

is sufficient. 6. Apparatus 6.1 Both the fixed end point test (Method A) and the quantitative test (Method B) are available as completely self-contained test kits containing all the reagents necessary to complete the test. 3 Each kit includes a sampling syringe to withdraw a fixed volume of sample for analysis; a first polyethylene test tube into which the sample is introduced for dilution and reaction with metallic sodium; a second polyethylene tube containing a buffered aqueous extractant, the mercuric nitrate titrant (Method A only), and diphenyl carbazone indicator; a polypropylene filter funnel; and a lmL titration syringe filled with mercuric nitrate titrant (Method B only). 6.2 If prepackaged kits are not used, the following materials and reagents will be required. 6.2.1 Test Tubes, two test tubes capable of holding 30 mL, sealed with screw caps. 6.2.2 Filtration Device, composed of a funnel containing a plug of polypropylene felt (or equivalent) to retain residual hydrocarbons from 5 mL of aqueous solution. 6.2.3 For quantitative Method B only, a 1.0-mL polypropylene tuberculin type syringe or equivalent. The syringe is to be marked with divisions at every 0.025 mL.

7. Reagents 7.1 If prepackaged kits are to be used, all necessary reagents and instructions are contained within the kits. 7.2 If not using prepackaged kits, the following must be prepared. 7.2.1 A solution of 10% (m/m) naphthalene in bis2-methoxy-ethyl ether (diglyme). Dissolve l0 g of naphthalene into 90 g of bis-2-methoxy-ethyl ether. 7.2.2 A dispersion of 40 % (m/m) ground sodium in mineral oil. 7.2.3 A 0.15 % (mass/volume) solution of s-diphenyl carbazone in ethyl alcohol. Dissolve 0.15 g s-diphenyl carbazone powder into 100 mL of ethyl alcohol. 7.2.4 For Method A, a 4.75-mmol/L solution of mercuric nitrate. Prepare a mercuric nitrate stock solution by first dissolving 5.14 g Hg(NO3)2.H20 (WARNING: EXTREMELY TOXIC) in 5 mL of 50 % (vol/vol) nitric acid. After solute has completely dissolved, make up to 150 mL with Type II water. Stock solution = 0.100 mol/L. Prepare 4.75 mmol/L solution by putting 47.5 mL of stock solution 3 Clor-D-Tect 1000 (Method A) and Clor-D-Tect Q4000 (Method B), available from Dexsil Corp., One Hamden Park Dr., H/~mden,CT 06517, have been found satisfactory for this purpose.

878

8.1 Using a volumetric pipette, place 0.40 _+ 0.02 mL of sample into one of the polyethylene tubes. 8.2 Using a volumetric pipette, add 1.5 mL of naphthalene/bis-2-methoxyethyl ether solution. Shake well. 8.3 Add 200 mg of metallic sodium dispersion (80 mg Na) and shake well for l min. 8.4 Add 7 mL of aqueous buffer solution to the mixture. Cap and shake well. Vent the tube so that the resulting pressure is released. 8.5 Allow the aqueous and hydrocarbon phases to separate for 2 min. Decant off the aqueous phase and pass 5 mL through the polypropylene filter into a second polyethylene tube. 8.6 Method A (Qualitative at 1000 mg/kgO--Add 0.75 mL of 4.75 mmol/L mercuric nitrate solution to the 5 mL of aqueous filtrate. Shake well. 8.6.1 Add approximately 0.5 mL of diphenylcarbazone indicator solution. Shake well. 8.6.2 Observe color. A violet solution means the original oil sample contains less than 1000 mg/kg total chlorine. A yellow or colorless solution means the oil sample contains greater than 1000 mg/kg total chlorine. 8.7 Method B (Quantitative to 4000 mg/kg)nFill the 1 cc tuberculin syringe with 13.7 mmol/L of mercuric nitrate solution to a volume of 1.0 mL by placing the tip of the syringe in the mercuric nitrate solution and withdrawing the plunger slowly until the syringe is full. If a burette is used instead of a syringe, fill the burette with the mercuric nitrate solution and dispense solution until the meniscus is at the zero point. 8.7.1 Add approximately 0.5 mL of diphenylcarbazone solution to the 5 mL of aqueous filtrate and mix well. 8.7.2 Place the filled tuberculin syringe in the polyethylene tube containing the aqueous filtrate and indicator reagent, and slowly depress the syringe so that the mercuric nitrate titrant is dispensed drop by drop. If the burette is used, add titrant drop by drop. Gently shake the solution between each drop. Stop titrating when a persistent violet TABLE 1 mg/kg CI ( p p m ) 100 500 1000 1500 2000 2500 3000 4000

Repeatability and Reproducibility Repeatability 46.1X °,2s Reproducibility 84.44X0.25 146 216 259 287 308 326 341 367

267 399

474 525 565 597 625 672

~t~) D 5 3 8 4 study, 4 ten laboratories analyzed seven used oil samples and one unused motor oil sample using prepackaged test kits. Each laboratory ran each sample in duplicate. Out of the eighty samples that were run, one laboratory's results disagreed with the rest of the laboratories' results on one sample. All 79 other tests were in agreement with their duplicates and with other laboratories' results. These data indicate that all participants get results of <1000 for all samples containing less than 870 mg/kg C1, 9 out of l0 get >1000 on a sample at 1180 mg/kg, and all participants get >1000 at and above 1272 mg/kg. These data indicate that this test method makes correct predictions for samples containing <870 or >1272 mg/kg and probably correct predictions for samples between 870 and 1272 mg/kg Cl. 11.2 Precision and Bias Statement for Method B. 11.2.1 Precision--The following criteria should be used for judging the acceptability of results. 11.2.2 Repeatability--The difference between successive test results obtained by the same operator with the same apparatus under constant operating conditions on identical test material would, in the long run, and in the normal and correct operation of this test method, exceed the stated values only in one case in twenty. Repeatability = 46. l X °,25

color remains throughout the solution. 8.7.3 Examine the titrating syringe and determine where the tip of the plunger is in relation to the scale marked on the outside of the syringe barrel. Determine the amount of titrant (to the nearest 0.025 mL) that has been used.

9. Interpretation of Results 9.1 Calculations are not required when prepackaged kits are used. 9.2 For Method A, report results as either greater than or less than 1000 mg/kg (ppm). 9.3 For Method B, calculate the concentration (mg/kg) of total chlorine in the original oil sample by the following equation: Chlorine (mg/kg) = ( V - 0.05)(c)(35.45)(F) m

(1)

where: V = volume of mercuric nitrate titrant used, mL, 0.05 = volume of excess titrant required for color formation, mL, c = concentration of mercuric nitrate solution, meq/L, for example, 27.4, 35.45 = average atomic weight of chlorine, F = dilution factor due to adding 7 mL of buffer solution and extracting only 5 mL for analysis, for example, 1.4, and m = mass of oil sample used, for example, 0.34 g for a volume of 0.4 mL motor oil, g.

where: X = method result, mg/kg. I 1.2.3 Reproducibility--The difference between two single and independent results obtained by different operators working in different laboratories on identical test material would, in the long run, and in the normal and correct operation of this test method, exceed the stated x,alues only in one case in twenty.

10. Quality Control

Reproducibility = 84.44 X ° 25

10.1 Test each sample two times. For Method A, if the results do not agree, a third test must be performed. Report the results of the two that agree. For Method B, the two results should be within 20 % or 300 mg/kg (whichever is larger) of each other. If they are not, perform a third test and report the results of the two tests that agree.

where: X = method result, mg/kg. 11.2.4 In a collaborative study, 4 using prepackaged kits, ten laboratories analyzed seven used oil samples and one unused motor oil sample. 11.2.5 Bias--No bias statement is made for this test method because results obtained for total chlorine were determined only by the test method itself.

11. Precision and Bias

12. Keywords 12.1 chlorine; field test; halogen; on-site testing; test kit; used oil

11.1 For Method A, no formal statement is made about either the precision or bias of the test method because the result merely states whether there is conformance to the criteria for success specified in the procedure, that is, a blue or yellow color in the final solution. In a collaborative

4 Data supporting this study is available from ASTM Headquarters. Request RR:D02-1368,

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, end the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reeppreved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend, if you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103.

879

q~l~ Designation: D 5386 - 93b Standard Test Method for Color of Liquids Using Tristimulus Colorimetry I This standard is issued under the fixed designation D 5386; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (~) indicates an editorial change since the last revision or reapproval.

1. Scope 1.1 This test method covers an instrumental method for the CIE (Commission International de l'Eclairage) tristimulus measurement of the color of near-clear liquid samples. The measurement is converted to color ratings in the platinum-cobalt system. 1.2 This test method has been found applicable to the color measurement of clear, liquid samples, free of haze, with nominal platinum cobalt color values in the 0 to 30 range. It is applicable to nonfiuorescent liquids with light absorption characteristics similar to those of the platinum cobalt color standard solutions. Test Methods D 1686, D2108, and E 450 deal with the visual and instrumental measurement of near-clear liquids. 1.3 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 2. Referenced Documents

2.1 A S T M Standards: D 1193 Specification for Reagent Water2 D 1209 Test Method for Color of Clear Liquids (PlatinumCobalt Scale)3 D 1686 Test Method for Color of Solid Aromatic Hydrocarbons and Related Materials in the Molten State (Platinum-Cobalt Scale)3 D 1925 Test Method for Yellowness Index of Plastics 4 D2108 Test Method for Color of Halogenated Organic Solvents and Their Admixtures (Platinum-Cobalt Scale)5 D 3437 Practice for Sampling and Handling Liquid Cyclic Products5 E 179 Guide for Selection of Geometric Conditions for Measurement of Reflectance and Transmission Properties of Materials6 E 308 Test Method for Computing the Colors of Objects by Using the CIE System6 t This test method is under the jurisdiction of ASTM Committee DI6 on Aromatic Hydrocarbons and Related Chemicals and is the direct responsibility of Subcommittee DI6.0E on Instrumental Analysis. Current edition approved Sept. 15 and Oct. 15, 1993. Published December 1993. Originally published as D 5386 - 93. Last previous edition D 5386 - 93. 2 Annual Book of ASTM Standards, Vols 06.01 and 11.01. 3 Annual Book of ASTM Standards, Vol 06.04. 4 Annual Book of ASTM Standards, Vol 08.02. Annual Book of ASTM Standards, Vol 15.05. 6 Annual Book of ASTM Standards, Vol 06.01.

E 450 Method for Measurement of Color of Low-Colored Clear Liquids Using the Hunterlab Color Difference Meter7 E 691 Practice for Conducting an Interlaboratory Study to Determine the Precision of Test Methodss 2.2 Other Document: OSHA Regulations, 29 CFR, paragraphs 1910.1000 and 1910.12009 3. Summary of Test Method 3.1 Color is measured by tristimulus values of light transmitted by a sample as percent of light transmitted by distilled water. Convert the measured tristimulus values by appropriate equations to the platinum-cobalt scale. 4. Significance and Use 4.1 The major objective of the visual platinum-cobalt (Pt-Co) method of color measurement, as defined in Test Method D 1209, is to rate specific materials for yellowness. This yellowness is frequently the result of the undesirable tendency of liquid hydrocarbons to absorb blue light due to contamination in processing, storage or shipping. 4.2 Clear liquids can be rated for light absorbing yellowish or brownish contaminants, using scales that simulate the long-established visual-comparison method just cited. Where needed, dimensions of color can be reported to identify any pinkness or greenness (one dimension), or grayness. 5. Apparatus 5.1. Instrument, with the following provisions: 5.1.1 Instrument Sensor, shall provide a beam for illuminating the sample cell in transmission. The instrument shall be capable of converting fight measured in total transmission through the sample cell to CIE X Y Z tristimulus color values for the measurement conditions of CIE illuminant C and the CIE 1931 2 degree standard observer as described in Practices E 179 and Test Method E 308. 5.1.2 The CIE X Y Z tristimulus color values shall be convertable to the instrumental yellowness index (Y1) defined by Test Method D 1925 and Test Method E 308. A correlation between measured yellowness index (3(I) (Test Method D 1925) values and the Pt-Co standard solutions shall be used to yield an equivalent instrumental Pt-Co rating for liquid hydrocarbon samples. 7 Discontinued 1993; see 1992 Annual Book of ASTM Standards, Vol. 15.05. s Annual Book of ASTM Standards, Vols 06.04 and 14.02. 9 Available from the Superintendent of Documents, U.S. Government Printing Office, Washington, D e 20402.

880

~ D 5386 5.1.3 Sample Cells, shall have clear, colorless, parallel entrance and exit windows. Internal distance between faces shall be selectable. Pathlengths from 20 mm to 150 mm have been used for near-clear liquid hydrocarbons. If measuring samples using cells of the same pathlength, a pathlength tolerance of +3 % or less would be appropriate. Matched cells would be beneficial but not required.

6. Reagents

6.1 Purity of Reagents--Reagent grade chemicals shall be used in all tests. 6.2 Purity of Water--References to water shall be understood to mean colorless distilled Water, conforming to Type IV of Specification D 1193. 6.3 Cobalt Chloride, (CoC12.6H20). 6.4 Hydrochloric Acid (sp gr I. 19)--Concentrated hydrochloric acid (HCI). 6.5 Potassium Chloroplatinate, (K2ItC16). 6.6 Platinum-Cobalt Stock Solution--Dissolve 1.245 g of potassium chloroplatinate (K2PtCIt) and 1.00 g of cobalt chloride (CoCI2 H20) in water. Carefully add 100 mL of hydrochloric acid (HCI sp gr 1.19) and dilute to 1 L with distilled water. The absorbance of the 500 platinum-cobalt stock solution in a cell having a 10-ram light path with distilled water in a matched cell as the reference solution must fall within the limits given in Table 1. 7. Materials

7.1 Platinum-Cobalt Standards--From the stock solution prepare color standards in accordance with Table 2 by diluting the required volumes to 100 mL with water in volumetric flasks. When properly sealed and stored these standards are stable for at least one year. 8. Hazards 8.1 Consult current OSHA regulations and suppliers' Material Safety Data Sheets for all materials used in this test method. TABLE 1

Abaorbance Tolerance Limits for No. 500 PlatinumCobalt Stock Solution

Wavelength

Absorbance

430 455 480 510

0.110 to 0.120 0.130 to 0.145 0.105 to 0.120 0.056 tO 0.065

TABLE 2

Platinum-Cobalt Colar Stsndarda

Color Standard Number

Stock Solution, mL

1 2 3 4 5 6 7 8 9

0.20 0.40 0.60 0.60 1.00 1.20 1.40 1.60 1.80

Cokx Standard Stock Solution mL Number 10 11 12 13 14 16 20 25 30

2.00 2.20 2.40 2.60 2.80 3.00 4.00 5.00 6.00

9. Sampling and Handling 9.1 Refer to Practice D 3437 for proper sampling and handling of liquid hydrocarbons analyzed by this test method. 10. Calibration 10.1 Prepare instrument for operation by following the instrument manufacturer's instructions. 10.2 Use instrument standardizing adjustments or program to obtain a It-Co value of 0 for a sample of distilled water. 10.3 Measured on a regular basis an intermediate It-Co standard solution in the It-Co range of the samples being analyzed, would verify instrumental performance. It is desirable for the user to be able to adjust the instrument to match the It-Co standard solutions as defined in 7.1. 11. Procedure 11. l Check to be sure that the instrument is operating in accordance with the manufacturer's operations manual. 11.2 Take three (3) instrumental readings without sample replacement, with the average taken as being a representative It-Co measurement of the sample. Exercise care to avoid sample contamination. 12. Report 12. l Report the following information: 12.1. l Sample identification, and 12.1.2 Instrumental It-Co measurement to nearest whole unit. 13. Precision and Bias 1°

13.1 Precision--The data for determining the precision of this test method are based on the analyses of o-xylene, styrene, and toluene at approximate values of 4, 8 and 12 respectively. Solutions prepared at levels of approximately 5, 10, 15 and 25 It-Co units were also included in the round robin. 13.2 Under the guidelines of Practice E 691, the following criteria should be used to judge the acceptability (95 % probability) of results obtained by this test method. The criteria were derived from a round robin between ten laboratories. Each one of the seven samples was run on two different days in each laboratory. 13.2.1 Repeatability--Two single test results obtained from the same laboratory should not be considered suspect unless they differ by more than 0.9 It-Co units. 13.2.2 Reproducibih'ty--Two single test results obtained from different laboratories should not be considered suspect unless they differ by more than 2.0 It-Co units. 13.3 Bias--The bias of this test method cannot be determined because no referee method is available to determine the true value. 14. Keywords 14. I color; hydrocarbons; platinum-cobalt; tristimulus io Supporting data are available from ASTM Headquarters. Request RR:DIt. 1012.

881

q~) D 5386 The American Society for Testing and Materiels takes no position respecting the validity of any patent rights asserted In connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the vatldlty of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision st any time by the responsible technical committee and must be reviewed every five years and if not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend, ff you feel that your comments have not received s fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103.

882

q~

Designation:D 5442 - 93 Standard Test Method for Analysis of Petroleum Waxes by Gas Chromatography 1 This standard is issued under the fixed designation D 5442; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsiion (~) indicates an editorial change since the last revision or rcapproval.

3.1.1 carbon number--a number corresponding to the number of carbon atoms in a hydrocarbon. 3.1.2 cool on-column injection--a sample introduction technique in gas chromatography where the sample is injected inside the front portion of a partition column at a temperature at or below the boiling point of the most volatile component in the sample. 3.1.3 low volume connector--a metal or glass union designed to connect two lengths of capillary tubing. Usually designed so that the tubing ends are joined with a minimum of either dead volume or overlap between them. 3.1.4 non(normal para~n)hydrocarbon (NON)--aU other hydrocarbon types excluding those hydrocarbons with carbon atoms in a single length. Includes aromatics, naphthenes, and branched hydrocarbon types. 3.1.5 normal paraffin--a saturated hydrocarbon which has all carbon atoms bonded in a single length, without branching or hydrocarbon rings. 3.1.6 wall coated open tube (WCOT)wa term used to specify capillary columns in which the stationary phase is coated on the interior surface of the glass or fused silica tube. Stationary phase may be cross-linked or bonded after coating.

1. Scope 1.1 This test method covers the quantitative determination of the carbon number distribution of petroleum waxes in the range from n-Cl7 through n-C44 by gas chromatography using internal standardization. In addition, the content of normal and non.normal hydrocarbons for each carbon number is also determined. Material with a carbon number above n-C44 is determined by difference from 100 mass % and reported as C45+. 1.2 This test method is applicable to petroleum derived waxes, including blends of waxes. This test method is not applicable to oxygenated waxes, such as synthetic polyethylene glycols (for example, Carbowax2), or natural products such as beeswax or carnauba. 1.3 This test method is not directly applicable to waxes with oil content greater than 10 % as determined by Test Method D 721. 1.4 The values stated in SI units are to be regarded as the standard. 1.5 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to consult and establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Specific precautionary statements are given in Notes 1 and 2.

4. Summary of Test Method 4.1 Weighed quantities of the petroleum wax and an internal standard are completely dissolved in an appropriate solvent and introduced into a gas chromatographic column that separates the hydrocarbon components by increasing carbon number. The column temperature is linearly increased at a reproducible rate until the sample is completely eluted from the column. 4.2 The eluted components are detected by a flame ionization detector and recorded on a strip chart or computer system. The individual carbon numbers are identified by comparing the retention times obtained from a qualitative standard with the retention times of the wax sample. The percent of each hydrocarbon number through C~ is calculated via internal standard calculations after applying response factors. 4.3 For samples with final boiling points greater than 538°C complete elution of all components may not be achieved under the specified conditions. For this reason, the C45+ material is determined by summing the concentrations of each individual carbon number through C~ and subtracting this total from 100 mass %.

2. Referenced Documents

2.1 ASTM Standards: D 721 Test Method for Oil Content of Petroleum Waxes3 D 4307 Practice for Preparation of Liquid Blends for Use as Analytical Standards 4 D4419 Test Method for Determination of Transition Temperatures of Petroleum Waxes by Differential Scanning Calorimetry4 D 4626 Practice for Calculation of Chromatographic Response Factors* E 260 Practice for Packed Column Gas Chromatography 5 E 355 Practice for Gas Chromatography Terms and Relationships 5 3. Terminology 3.1 Descriptions of Terms Specific to This Standard: This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.04.0L on Gas Chromatography. Current edition approved Dec. 15, 1993. Published February 1994. 2 Carbowax is a registered trademark of Union Carbide Corp. 3 Annual Book of ASTM Standards, Vol 05.01. 4 Annual Book of ASTM Standards, Vol 05.02. 5 Annual Book of ASTM Standards, Vol 14.01.

5. Significance and Use 5.1 The determination of the carbon number distribution of petroleum waxes and the normal and non-normal hydrocarbons in each can be used for control of production 883

~

D 5442

processes as well as a guide to performance in many end UseS.

5.2 Data resulting from this test method are particularly useful in evaluating petroleum waxes for use in rubber formulations. 6. Apparatus 6.1 Chromatograph--Any gas chromatographic instrument that can accommodate a WCOT column, equipped with a flame ionization detector (FID), and that can be operated at the conditions given in Table 1 may be employed. The chromatograph should be equipped with a cool on-column inlet (or equivalent) for introducing appropriate quantities of sample without fractionation. In addition, the gas chromatograph must be capable of generating a chromatogram where the retention times of an individual peak have retention time repeatability within 0.1 min. Refer to Practices E 260 and E 355 for general information on gas chromatography. 6.2 Sample Introduction System--Any system capable of introducing a representative sample onto the front portion of a WCOT column may be employed. Cool on-column injection is preferred, however other injection techniques can be used provided the system meets the specification for linearity of response in 9.6. For cool on-column injection, syringes with 0.15 to 0.25 mm outside diameter needles have been used successfully for columns 0.25 mm inside diameter or larger and standard 0.47 mm outside diameter syringe needles have been used for columns 0.53 mm inside diameter or greater. 6.2.1 Care must be taken that the sample size chosen does not allow some peaks to exceed the linear range of the detector or overload the capacity of the column. 6.3 Column(s)--Any column used must meet the chromatographic resolution specification in 9.5. WCOT columns with 25 to 30 m lengths and a stationary phase coating of methyl siloxane or 5 % phenyl methyl siloxane have been successfully used. Cross-linked or bonded stationary ~hases are preferred. 6.4 Recorder--A recording potentiometer or equivalent TABLE 1 Typical Operating Conditiona Column length (m): 25 Column inside 0.32 diameter (ram): Stationary phase: DB-1 methyl silicone Film thickness ~m): Carder gas: Carder flow (mL/min): Linear velocity

30 0.53

15 0.25

RTX-1 methyl silicone

0.25

0.25

DB-5 5 Y, phenyl methyl silicone 0.25

Helium 1.56

Helium 5.0

Helium 2.3

33

35

60

80

80

8

5

340

350

cool on-column 400

cool on-column 375

1.0

1.0

(era/s): Column Initial 80 temperature (eC): Program rate 10 (*C/mln): Final temperature 380

(*C): Injection technique: cool on-column Detector tern380 perature (*C): Sample size (/.tL): 1.0

884

with a full-scale deflection of 5 mV or less for measuring the detector signal versus time. Full scale response time should be 2 s or less. Sensitivity and stability should be sufficient to generate greater than 2 mm recorder deflection for a hydrocarbon injection of 0.05 mass % under the analysis conditions employed. 6.5 Integratoror Computer--Means must be provided for integrating the detector signal and summing the peak areas between specific time intervals. Peak areas can be measured by computer or electronic integration. The computer, integrator, or gas chromatograph must have the capability of subtracting the area corresponding to the baseline (blank) from the sample area, and have the ability to draw the baselines used for peak area integration. 7. Reagents and Materials

7.1 Carrier Gas--Carrier gas appropriate for the flame ionization detector. Hydrogen and helium have been used successfully. The minimum purity of the carrier gas used should be 99.95 mol%. NOTE h Wm'nlng--Hydrogen and helium are compressed gases under high pressure. Hydrogenis an extremelyflammablegas. 7.2 n-hexadecane--Hydrocarbon to be added to samples as an internal standard. Minimum purity of 98 % is required. 7.3 Standards for Calibration and Identification--Standard samples of normal paraffins covering the carbon number range (through C~) of the sample are needed for establishing the retention times of the individual paraffins and for calibration for quantitative measurements. Hydrocarbons used for standards must be greater than 95 % purity. 7.4 Solvent--A liquid (99 % pure) suitable for preparing a quantitative mixture of hydrocarbons and for dissolving petroleum wax. Cyclohexane has been used successfully. NOTE 2: Warning--Solvents are flammable and harmful ff inhaled. 7.5 Linearity Standard--Prepare a weighed mixture of n-paraffins covering the range between n-C=6 to n-C44 and dissolve the mixture in cyclohexane. Use approximately equal amounts of each of the paraffins and a balance capable of determining mass to within 1% of the mass of each compound added. It is not necessary to include every n-paraffin in this mixture so long as the sample contains n-Cl6, n-C44, and at least one of every fourth n-paraffin. It will be necessary to prepare the standard sample in cyclohexane, so that the normal paraffins are completely dissolved in the solvent. Solutions of 0.01 mass % n-paraffin have been used successfully. This sample must be capped tightly, to prevent solvent loss which will change the concentration of paraffins in the standard blend. NOTE 3--Refer to Practice D 4307 for details of how to prepare hydrocarbon mixtures. 7.6 Internal Standard Solution--Prepare a dilute solution of internal standard in cyclohexane in two steps as follows: 7.6.1 Prepare a stock solution containing 0.5 mass % n-C~6 in cyclohexane by accurately weighing approximately 0.4 g n-Ct6 into a 100 mL volumetric flask. Add 100 mL of cyclohexane and reweigh. Record the mass of n-Ci6 to within 0.001 g and the mass of solution (cyclohexane and n-Cmt) to within 0.1 g. 7.6.2 Prepare a dilute solution of n-C~6 internal standard

~

D 5442 9.3.1 Baseline Bleed--Observe the detector response from the blank run on the recorder. Some increase in detector response will be observed at the upper column temperatures due to stationary phase bleed. Column bleed is acceptable so long as the duplicate baseline blank analyses are repeatable. The baseline should be a smooth curve, free of any chromatographic peaks. 9.4 Solvent Blank--Make a 1 ~tL injection of the cyclohexane solvent and program the column oven. The solvent is of suitable purity if there are no detected peaks within the retention time range over which the wax samples elute. 9.5 Column Resolution--Check the efficiency of the G-C column by analyzing, under conditions specified in 10.2, a 1 IxL injection of 0.05 mass % solution of n-C2o and n-C24 in cyclohexane. The column resolution must not be less than 30 as calculated using Eq 2. 2d R = 1.699(W1 + W'2) (2)

by diluting one part of stock solution with 99 parts of cyclohexane. Calculate the concentration of internal standard in the dilute solution using Eq 1.

CisTD ffi where: Czsro l,Vtsro Ws 100 % 100

WzsrD 1O0 % x Ws 100

(1)

= mass % n-C~6 internal standard in dilute solution, = weight of n-Cl6 from 7.6.1, = weight of cyclohexane plus n-C16 from 7.6.1, ffi factor to convert weight fraction to mass %, and ffi dilution factor.

8. Sampling 8.1 To ensure homogeneity, completely mix the entire wax sample by heating it to 10*C above the temperature at which the wax is completely molten and then mix well by stirring. Using a clean eyedropper, transfer a few drops to the surface of a clean sheet of aluminum foil, allow to solidify and break into pieces. The wax can either be used directly as described in Section 11 or placed in a sealed sample vial until ready for use. 8.1.1 Aluminum foil usually contains a thin film of oil from processing. This oil must be removed by rinsing the foil with solvent such as hexane or mineral spirits, prior to use.

where: d = distance (mm) between the peak maxima of n-C2o and n-C24, W1 ffi peak width (mm) at half height of n-C2o, and W2 ffi peak width (ram) at half height of n-C24. 9.6 Linearity of Response--For quantitative accuracy, detector response must be proportional to the mass of hydrocarbon injected, and the response of the non-normal paraffins is assumed to be equivalent to the response of the n-paraffin with the same carbon number. In addition, sample injection technique and sample solution properties must be such that representative sample is introduced to the gas chromatograph without discrimination. Before use, the analysis system must be shown to conform to these requirements as specified in 9.6.1. 9.6.1 Analyze the linearity standard described in 7.5 and calculate the relative mass response factors according to Practice D 4626. Response factors calculated relative to hexadecane must be between 0.90 and 1.10. 9.6.2 If relative response factors are not within the limits stated above, take appropriate action and reanalyze the lincarity standard to ensure linearity and the absence of discrimination. 9.7 Retention Time Repeatability---Check the retention time repeatability by analyzing the linearity standard in duplicate. Retention times for duplicate analyses must not differ by more than 0.10 rain between duplicate runs.

9. Preparation of Apparatus 9.1 Column Conditioning--Capillary columns with bonded (or cross-linked) stationary phases do not normally need to be conditioned; however, it is good chromatographic practice to briefly condition a new column as described below. 9.1.1 Install the column in the chromatographic oven and connect one column end to the sample inlet system. Turn on the source of carrier gas and set the flow controller (or pressure regulator) to the flow rate to be used in the analysis. Increase the column temperature to the maximum value to be used in the analysis and maintain this temperature for 30 min. Cool the column temperature to room temperature and connect the remaining column end to the detector. Care must be taken that the column terminates as dose as possible to the tip of the l i D jet. The temperature of the column between the column oven and the detector jet must be maintained above the maximum column temperature. 9.2 Operating Conditions--Set the chromatographic operating conditions (see Table 1) and allow the system to achieve all temperature setpoints. The recorder, computer or integrating device should be connected so that a plot of the detector signal vs time can be obtained. Make certain that the FID is ignited before proceeding. 9.3 Baseline Blank--After conditions have been set to meet performance requirements, program the column temperature upward to the maximum temperature to be used. Once the column oven temperature has reached the maximum temperature, cooI the column to the selected starting temperature. Without injecting a sample, start the column temperature program, the recording device and the integrator. Make two baseline blank runs to determine if the baseline blank is repeatable. If the detector signal is not stable or if the baseline blanks are not repeatable, then the column should either be conditioned further or replaced.

10. Calibration and Standardization 10.1 n-Para~n Identification--Determine the retention time of each n.paraffin in the range from Cl~ to C~ by injecting small amounts of each paraffin either separately or in known mixtures. Completely dissolve samples in cyclohexane. 10.2 Standardization--Inject the linearity standard described in 7.5 and measure the peak area of each n-paraffin by electronic integrator or computer. 10.2.1 Calculate the response per unit mass of the detector for each component in the linearity standard, relative to n-C16, according to Practice D 4626. 885

~

D 5442

11. Procedure 11.1 Prepare a solution of the petroleum wax sample for analysis as follows: 11.1.1 Obtain a petroleum wax sample specimen as directed in 8.1. 11.1.2 Accurately weigh about 0.0100 g of the wax specimen into a glass vial of approximately 15 mL capacity. Add approximately 12 mL of the dilute internal standard solution (0.005 mass % n-C,6 in cyclohexane), cap the vial and determine the exact weight of dilute internal standard solution added. Record both weights. 11.1.3 Agitate the vial until the wax is dissolved, using genre heating if necessary. 11.1.4 For manual syringe injections, fill the syringe directly from this vial. For automatic syringe injections, transfer a suitable aliquot to the appropriate autosampler vial. 11.2 Before analyzing wax samples, program the column temperature to the maximum temperature used. Once the column temperature has reached the maximum, cool the column to the selected starting temperature, and allow it to equilibrate at this temperature for at least 3 rain. Without injecting any material, initiate a blank run by starting the temperature program, recorder, and integrator and allow to continue until at least 2 rain after the retention time of n-C~. Store a record of this blank run in the computer or integration device for subtraction from the sample area. Note 4--Some commercially available gas chromatographs have software routines as part of their standard systems to make the baseline correction directly to the detector signal. With such systems, no computer subtraction of the blank is necessary. 11.3 Following the same procedure as for the blank run (see 11.2), inject 0.5 to 1.0 ttL of the wax sample solution from 11.1 into the cool on-column injection port. Immediately start the temperature program, the recorder, and the integrator, and store the acquired detector signal. 11.4 Integrate the stored detector signal twice, using the baseline construction parameters as directed below. 11.4.1 Using a valley to valley baseline construction,

integrate the detector signal to obtain an area (see Fig. 1) for each peak in the chromatogram. Based on the retention times determined in 10.1, identify the normal paraffin peaks and tabulate only their areas. Also record the area of the n-C16 (hexadecane) internal standard peak that must be completely resolved (baseline separation) from the wax sample area. 11.4.2 Using a vertical drop to a horizontal baseline construction (see Fig. 2), integrate the detector signal a second time. Sum the area of all the peaks of each carbon number and tabulate these totals. By convention, the peaks assigned the carbon number n are those that elute between the valley immediately following the normal paraffin peak (C,q) and the corresponding valley following the next normal paraffin peak (C,). 11.4.3 To ensure proper and consistent integrations, plot the chromatogram with drawn in baseline after each integration and confirm that the baselines match Figs. 1 and 2. 11.4.4 Do not include, as part of the sample, any peaks resulting from the solvent or the internal standard. NOTE 5--The total area for each carbon number can be measuredby either pre-programming the integrator to sum the area of the peaks within the appropriate retention time windowsor by analyzing the peak area data al~r the peak integration processis complete. 12. Calculation 12.1 Each Carbon NumberwCalculate the mass % for each carbon number determined in 11.4.2 using Eq 3. AreaI C, . . ~

Arealsr~

MIX × RRF, ×

sample

C, areal

ffi mass % of hydrocarbons with carbon number i, = area sum of hydrocarbons with carbon number

i, arealsrD ffi area of n-C16 internal standard peak,

RRFi

= response factor, relative to n-Cnt,

MIX

= weight of dilute internal standard/solvent mix-

ture,

8.80

7.18

5.57

3.9~

! t J..0O.

I 14.62

!

! t 8 . P5

I 21 . 8 7

!

I 25.50

!

I 29 • t2

!

I 63q7t5 I 32.75 36.37

manures

FIG. 1

(3)

where:

t0.42

2.3

× C1sn,

Valley to Valley Integration for Area of Normal Paraffin

886

! 4 0 . O0

~) D 5442 3.5C

32~_ 3.0~

~.

2.rap

L ........... 2.6E

I

2.44 ~ 24.00. minutes

l a4.25

FIG. 2

,

I

•

_

24.50

I--_,

I

24.75

~

I---

25.00

,

25.25

I

,

25.50

I

25.74

a6.oo

C a r b o n N u m b e r S u m m a t i o n (Vertical D r o p to H o r i z o n t a l B a s e l i n e )

3.50 _

3.28 _

3.07 _

2.o~

,

24,.00. mlnutes

24.25

I

.-~-----

24.75

24.50

FIG. 3

I

X

CisTD

, __---L-

___~-.-..

;25.50

I

25.75

L~6.O0

MIX

ffi weight of dilute internal standard/solvent mixture, sample ffi weight of wax sample, and CzsrD = mass % of n-Ci6 in internal standard mixture. 12.3 Non-Normal Paraffin HydrocarbonnThe nonnormal paraffin hydrocarbons arc calculated as the difference between the mass percent of hydrocarbons with carbon number i (Cl) and the mass percent of the n-para~n with carbon number i (N;):

(4)

where:

N,

A

25.25

Typical Wax Chromatogram

sample = weight of wax sample, and CIsrD = mass % of n-C~6 in internal standard mixture. 12.2 Normal ParaffinwCalculate the mass % of each normal paraffin hydrocarbon from the individual areas determined in 11.4.1 using Eq 4. Areai MIX =- X RRFj X - Nt Areals-rD sample

,

25. O0

ffi mass % of normal paraffin with carbon number

NON,

i,

= C,- N I

(5)

where:

areai

= peak area of normal paraffin with carbon number i, arealsrD = area of n-C~s internal standard peak, RRF, -- response factor, relative to n-C~6,

mass percent of the non-normal paraffin hydrocarbons of each carbon number. 12.3.1 The response for all components in a carbon number is assumed to be the same as the response for the

NON(O

887

=

~h~ D 5442 TABLE 2

normal paraffin of the same carbon number as determined in 10.2. 12.3.2 Relative response factors for individual n-paraffins between those determined from the calibration mixture are obtained by interpolation. 12.4 Calculate the mass percent of C45+ according to Eq 6: mass % C45+ = 100 % - 7.Ct (6)

Repeatability and Reproducibility

Carbon Number Range,mass ~ C21 C=~ C=e C=o C~ C~ C= C41 C,~ Total n-paraffins

where: 2;C~ = the sum of the mass % of all detected hydrocarbons.

0.11-0.25 0.04-2.90 0.01-8.94 0.04-8.15 0.44-5.05 2.52-5.62 0.44-3.61 0.06-2.96 0.02-2.26 18.73-79.52

Repeatal~ty ~ 0.014 0.0463X°.~° 0.0785X°'se 0.0872X°~1 0.1038X°-s° 0.1737X 0.1131(X + 0.1069) 0.1600 X 0.4990X°'e° 2.64

ReproductbUity A 0.039 0.1663 X°'3° 0.4557 X°'~ 0.3984 X°'ca 0.6472 X°'s° 0.4540 X 0.6476(X + 0.1069) 0.6460 X 0.9220 X°'e° 26.03

A Where X is the mass percent of the component.

13. Report 13.1 Report the concentration in mass percent of the normal (Ni) and non-normal ( N O N i) hydrocarbons for each carbon number in the sample to the nearest 0.01 mass percent. Report also the amount of residual as % C45+.

test material, would, in the long run, in the normal and correct operation of the test method, exceed the values in Table 2 only in one case in twenty. 14.1.2 Reproducibility--The difference between two single and independent results, obtained by different operatots working in different laboratories on identical test materials would, in the long run, in the normal and correct operation of the test method, exceed the values in Table 2 only in one case in twenty. 14.2 Bias--Bias cannot be determined because there is no reference material suitable for determining the bias of the procedure in this test method.

14. Precision and Bias6 14.1 Precision--The precision of this test method as determined by statistical examination of intedaboratory test results is as follows: 14.1.1 Repeatability.--The difference between the two test results, obtained by the same operator with the same apparatus under constant operating conditions on identical

15. Keywords 15.1 gas chromatography; non-normal paraffin hydrocarbons; normal paraffin; paraffin wax; petroleum wax

6 Supporting data is available from ASTM headquarters. Request RR:D021316,

888

~

D 5442

The American Society for Testing and Materials takes no posit/on respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that daterrnlnaticn of the validity of any such patent rights, and the risk of infringement of such rights, a r e entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and ff not revised, either respproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend, ff you feel that your comments have not received e fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103.

889

(~T~ Designation: D 5443 - 93

Standard Test Method for Paraffin, Naphthene, and Aromatic Hydrocarbon Type Analysis in Petroleum Distillates Through 200°C by Multi-Dimensional Gas Chromatography 1 This standard is issued under the fixed designation D 5443; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last re.approval. A superscript epsilon (E) indicates an editorial change since the last revision or reapproval.

1. Scope 1.1 This test method provides for the determination of paraffins, naphthenes, and aromatics by carbon number in low olefinic hydrocarbon streams having final boiling points of 200"C or less. Hydrocarbons with boiling points greater than 200"C and less than 270"C are reported as a single group. Olefins, if present, are hydrogenated and the resultant saturates are included in the paraffin and naphthene distribution. Aromatics boiling at Ca and above are reported as a single aromatic group. 1.2 This test method is not intended to determine individual components except for benzene and toluene that are the only C6 and C7 aromatics, respectively, and cyclopentane, that is the only C s naphthene. The lower limit of detection for a single hydrocarbon component or group is 0.05 mass %. 1.3 This test method is applicable to hydrocarbon mixtures including virgin, catalytically converted, thermally converted, alkylated and blended naphthas. 1.4 The values stated in SI (metric) units are to be regarded as the standard. 1.5 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Specific precautionary statements are given in Notes 1 and 2 and Table 2.

hydrogenates olefins, if present, in this fraction, and then to a molecular sieve column which performs a carbon number separation based on molecular structure, that is, naphthenes and paraffins. The fraction remaining on the polar column is further divided into three separate fractions that are then separated on a non-polar column by boiling point. Eluting compounds are detected by a flame ionization detector. 3.2 The mass concentration of each group is determined by the multiplication of detected peak areas by flame ionization detector response factors and normalization to 100 %. 4. Significance and Use 4.1 A knowledge of the composition of hydrocarbon refinery streams is useful for process control and quality assurance. 4.2 Aromatics in gasoline are soon to be limited by federal mandate. This test method can be used to provide such information. 5. Interferences 5.1 Chemicals of a non-hydrocarbon composition may elute within the hydrocarbon groups, depending on their polarity, boiling point, and molecular size. Included in this group are ethers (for example, methyl-tertiary butyl ether) and alcohols (for example, ethanol). 6. Apparatus 6.1 Chromatograph--A gas chromatograph capable of isothermal operation at 130 -4-0. I*C. The gas chromatograph must contain the following: 6.1.1 A heated flash vaporization sample inlet system capable of operation in a splitless mode. 6.1.2 Associated gas controls with adequate precision to provide reproducible flows and pressures. 6.1.3 A flame ionization detection system optimized for use with packed columns and capable of the following:

2. Referenced Documents

2. l ASTM Standards: D4057 Practice for Manual Sampling of Petroleum and Petroleum Products 2 D 4307 Practice for Preparation of Liquid Blends for Use As Analytical Standards 2 3. Summary of Test Method 3.1 A representative sample is introduced into a gas chromatographic system containing a series of columns and switching valves. As the sample passes through a polar column, the polar aromatic compounds, bi-naphthenes, and high boiling (>200"C) paraffins and naphthenes are retained. The fraction not retained elutes to a platinum column, that

Isothermal temperature operation . . . . . . . . . . . . Sensitivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Minimum detectability . . . . . . . . . . . . . . . . . . . . . . Linearity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

150 to 170"C >0.015 coulombs/g 5 × 10-12 g carbon/second >107

Some instruments will produce a non-linear response for benzene, above approximately 5.5 mass %, and for toluene above approximately 15 mass %. The linearity of these components above these concentrations must be verified with appropriate blends. Where non-linearity has been shown to exist, samples, that contain no higher than C~3, can be analyzed if the sample is diluted with n-Cm5 and the

s This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.04.0L on Gas Chromatography. Current edition approved Aug. 15, 1993. Published October 1993. "Annual Book of ASTM Standards, Vol 05.02.

890

~) O 5443 TABLE 1 Specifw,ation

Typical Column

Specifications Column Type

Polar

Non-Polar

Tenaxa

4 1.8 to 2.0 OV-101 c 4-5 Chromasorb ° WAW __.

0.16 to 0.18 2.5

Packing material

3 2.0 to 2.1 OV-275 B 30 Chromasorb o PAW __.

:renaxa

M~ecular sieve 13X e'~=

Mesh size

60/80

80/100

80/100

.

Column length, m Column inside diameter, mm Liquid phase Percent liquid phase Support matarlal

. .

. .

.

.

Molsieve A

. .

.

Ratinum A

1.8 1.6 to 2.0 . .

.

. .

.

0.002 to 0.06 1.6

. .

.

.

. .

. .

.

.

. .

.

.

.

.

... ... .

A See Footnote 4 for commercial columns availability. a See Footnote 8 for information on 0V-275. c See Footnote 8 for Information on OV-101. o See Footnote 9 for information on Chromasorb. e Sodium form of molecular sieve 13X. F May also contain a mix of molecular sieves 13X and 5A to separate normal and iso-peraffins.

instrument is equipped with a prefractionating column. The sample may also be diluted with a component that is not present in the sample and this component will then not be included in the normalized report. 6.2 Sample Introduction System--Manual or automatic liquid sample system operated in a splitless mode. Although this test method is intended primarily for use with syringe sample injection, automatic sampling valves have also been found satisfactory. Devices capable of a reproducible injection volume of 0.1 to 0.5 pL are suitable. The sample introduction system must be capable of heating the sample to a temperature that ensures total sample vaporization. A temperature range of 120 to 180°C has been found suitable. 6.3 ElectronicData Acquisition System--The data acquisition and integration device used for detection and integration must meet or exceed the following specifications: 6.3.1 Capacity for at least 75 peaks for each analysis, 6.3.2 Normalized area percent calculation, 6.3.3 Noise and spike rejection capability, 6.3.4 Sampling rates for fast (<2 s) peaks, 6.3.5 Peak width detection for narrow and broad peaks, and 6.3.6 Perpendicular drop and tangent skimming as required. 6.4 Independent Temperature Control--This test method requires the temperature control of five columns, column switching valves and sample lines. The columns consist of polar, non-polar, Tenax3, platinum, and molecular sieve columns. The specifications for these columns are listed in Table I. The polar column, non-polar column, column switching valves, and sample lines require isothermal operation at a temperature equivalent to the temperature of the gas chromatograph oven. These components may be located in the gas chromatograph oven. The Tenax 3 column, platinum column, and molecular sieve column require operation at temperatures other than the gas chromatograph oven temperature. These columns may be temperature controlled by any means that will meet the following specifications: 6.4.1 Ability to control the temperature of the Tenax 3 column within a range of 60 io 280°C, with a tolerance of _+50C at any point. The time required to heat this column 3Tenaxis a registeredtrademarkof AKZO,Velperives76, P.O. Box 9300, 6800SBArnhem,The Netherlands. 891

between any two points must be no more than 1 min. The time required to cool this column between any two points must be no more than 5 rain, 6.4.2 Ability to control the temperature of the molecular sieve column within a range of 100 and 4900C, with a tolerance of + 10°C at any point. The time required to heat this column between any two points must be no more than l0 rain. The time required to cool this column from 450 to 100*C must be no more than 15 min, and 6.4.3 Ability to control the platinum column within a temperature range of 170 and 350°C. During routine analysis, this column is operated within a temperature range of 170 to 2200C. 7. Materials 7.1 CarrierG~es: 7.1.1 Hydrogen, 99.999 % pure, <0.1 ppm H20. (Warning--See Note l.) NOTE I: Warning--F_.xtremelyflammablegas under high pressure.

7.1.2 Helium, 99.999 % pure, <0.1 ppm H20. (Warning--See Note 2.) NOTE 2: Warning---Compress~gas under high pressure. 7.2 Detector Gases: 7.2.1 Hydrogen, 99.99 % minimum purity. (Warning-See Note 1.) 7.2.2 Air, less than 10 ppm each of total hydrocarbons and water. (Warning--See Note 2.) 7.3 Valve Actuation Gas--This test method permits the use of any type of valve switching or valve actuation. When pneumatic valves are used, air of any grade that will result in no water condensation or will not introduce oil or other contaminates in the switching valves may be used. Air from a piston operated compressor equipped with a water and oil separator has been found suitable. Column switching valves that do not require air to operate do not have this air requirement. 7.4 Columns--Five columns, as described in Table 1. These column specifications are to be considered as guidelines and have been found to be acceptable. Other materials or combinations of materials may also provide acceptable performance. The suitability of each column is determined by test criteria as defined in Section 8. NOTE 3--It is not the intention of this test method to include detailed column preparation steps. Columns may be prepared in any

~r~,) D 5443 way that followsaccepted safetypractices and results in columns that will meet the performancerequirementsof Section 9. 7.5 ValvesmThis test method uses valves for column switching and flow switching. Any commercially available valves may be used that are intended for, or adapted for use in gas chromatography that meet the following specifications: 7.5.1 The column switching valves are generally installed in the gas chromatograph oven. These valves must be capable of continuous operation at the operating temperature of the GC oven. 7.5.2 Materials used in the construction of the valves must be unreactive to hydrocarbons present in the sample under analysis conditions. Stainless steel, PFA, and vespel materials have been found suitable. 7.5.3 Valves must be sized such that they offer little restriction to carrier gas flow under the analysis conditions defined in this test method. 7.5.1 Care must be taken to prevent the introduction of any form of foreign material or contaminant into the valve that may adversely affect its performance. 7.6 Hydrocarbon Test Mixture--A quantitative synthetic mixture of pure hydrocarbons, an example of which is identified in Table 2 is used to tune the instrument analysis conditions and establish that the instrument is performing within specifications. Individual hydrocarbon components, in addition to those listed in Table 2, may be used to aid in the analysis. The concentration level of each component in the hydrocarbon test mixture is not critical as long as the concentration is accurately known. Percentage ranges of 1.0 to 6.0 mass % have been found suitable. Impurities in the individual components may have an adverse effect on the quantitative aspect of the analysis. If an impurity is of the same carbon number and basic molecular structure as the TABLE 2 Hydrocarbons

Hydrocarbon Test Mixture Warning

Cyclopentane (Waming--Extremely Flammable. Harmful if inhaled.) Pentane (Warning--Extremely Flammable. Harmful if inhaled.) Cyclohexane (Wamlng--Extremaly Flammable. Harmful if inhaled.) 2,3-Dimethylbutane (Warning--Extremely Flammable. Harmful if inhaled.) Hexane (Waming--Extremaly Flammable. Harmful if inhaled.) 1-Hexene (Warning--Extremely Rammable. Harmful if inhaled.) Methylcyclohaxane (Warning--Extremely Flammable. Harmful if inhaled.) 4-Methyl-l-hexene (Warning--Extremely Flammable. Harmful if inhaled.) Heptane (Warning--Flammable. Harmful if inhaled.) 1 ,cis-2-Dimethylcyclohexane (Warning--Extremely Flammable. Harmful if

main component itself, it will be correctly grouped and quantitated within the group. As an example, isobutylcyclopentane and isopropylcyclohexane will both be determined as C9 naphthenes. Each of the individual hydrocarbon components used for this test mixture must have a minimum purity level of 99 mole %. Refer to Practice D 4307 for instructions on the preparation of liquid blends for use as analytical standards. 7.7 Gas Flows and Pressures: 7.7.1 Carrier Gases: 7.7.1.1 The helium carrier gas through the injection port, polar column, platinum column and molecular sieve column is flow controlled. Flow rates of 16 to 23 mL/min have been found suitable. A helium supply pressure of 620 kDa (90 psi) has been found suitable to meet the helium flow requirement. The helium carrier gas flow will be referred to as the A flow within this test method. 7.7.1.2 The helium carrier gas used as the make up gas when the polar column is in stop flow is set to the same flow rate as the helium carrier gas through the injection port. 7.7.1.3 The hydrogen carrier gas flow through the Tenax 3 column and non-polar column is flow controlled. Flow rates of 12 to 17 mL/min have been found suitable. A hydrogen supply pressure of 517 kDa (75 psi) has been found suitable to meet the hydrogen flow requirements. The hydrogen carrier gas flow will be referred to as the "B" flow within this test method. 7.7.1.4 The hydrogen flow to the platinum column is flow controlled. Flow rates of 10 to 15 mL/min have been found suitable. 7.7.2 Detector GaseswThe flow rates of the air and hydrogen, as oxidant and fuel gases for the flame ionization detector, must be set according to the instrument manufacturer's instructions. 7.7.3 Valve Actuation Gases--Pneumatic valves require air delivery at pressures and flows adequate to ensure correct actuation. When pneumatic valves are used for this test method, air pressure and flow must be provided in accordance with the valve manufacturer's instructions.

8. System Description 8.1 Commercial instruments are available that meet the specifications of this test method. One such system4 is based on pneumatic valves. Another system5 is based on rotary valves. Additional operating instructions are included in the operating and maintenance manuals for these instruments. The figures in this test method are applicable to these systems. 8.1.1 Figures 1 and 2 illustrate typical instrument configurations that use different column valve switching techniques. This test method allows use of either configuration. 8.1.2 Figures 3 through 13 illustrate the system flow configurations during the column test and sample analysis phases of this test method. 8.1.3 Tables 3 and 4 list the conditions that apply during

inha~d.)

2,2,4-Tdmethylpentane (iso-octane) (Waming--Flammable. Harmful if inhaled.) Octane (Warning--Flammable. Harmful if inhaled.) 1,CiSo2,Cis-4-Trimathylcyclohexane (Warning--Flammable. Harmful if inhaled.) Nonane (Warning--Flammable. Harmful if Inhaled.) Decane (Warning--Flammable. Harmful if Inhaled.) Undecane (Warning--Flammable. Harmful if inhaled.) Dodecane (Warning--Flammable. Harmful if inhaled.) Benzene (Warning--Extremely Flammable. Harmful if inhaled.) Methylbenzene (Toluene) (Wamlng--Flammable. Harmful if inhaled.) trans-Decahydronaphthalene (Decalin) (Warning--Flammable. Harmful if inhaled.) Tetradecane (Warning--Harmful if inhaled.) Ethylbenzene (Warning--Extremaly Flammable. Harmful if inhaled.) 1,2-Oimethylbenzene (o-Xylene) (Wamlng~Extremely Flammable. Harmful if inhaled .) Propylbanzene (Waming--Extramely Flammable. Harmful if inhaled.) 1,2,4-Trimethylbenzene (Warning--Extremely Flammable. Harmful if inhaled.) 1,2,3-Trimethylbenzene (Warning--Extremely Flammable. Harmful if inhaled.) 1,2,4,5-Tetramethylbenzane (Warning--Flammable. Harmful if inhaled.) Pentamethylbenzene (Warning--Harmful if inhaled.)

4 Instrument commercially available from AC Analytical Controls, 3448 Progress Drive, Bensalem, PA 19020. s Instrument commercially available from Chrompack, International BV 4330 EA Middleburg, The Netherlands.

892

(~ Ht FLO~ A

D 5443

POLAR COLUMN BYPASS VALVE BYPASS FLOW ADJUSTMENT

INJEOTZON

PORT

H2

FLOW O

l

PLATINUM HYDROGENATOR FLOW

PRESSURE REGULATOR

~.~

NEELDE VALVE

PORTSIJDERVALVE IN THE 0 POSITION

6

,

~

DIRECTIONAL SWITCHING VALVE

FLOW REGULATOR

6 PORTSLJDERVALVE IN THE I POSfflON

PRESSURE GAUGE

~

VALVEIN O F F PosmoN

DIRECTIONAL SWITCHING VALVE

FIG. 1 TypicalInstrument With Six Port Slider Valves t4YO~OGEN IPt,OW TO dLq,Al'lNt~ ¢ ( ~

HILUMPLOWFO~

p.

CO/.oJedNBYI'AS8 - "~7 p . . . . . . .

i ) o )

0--¢=-7

:

~MII,Ul

OHLET IIYIITIEM ~rlrlEOTOa

IP" HYi~N

PLOW

FIG. 3

Start of the "A" Time

the column test and sample analysis phases for the instrument configuration in Fig. 2. 8.2 The polar column separates the sample into four fractions. The first three fractions are fore-flushed through the polar column and the last is back-flushed. Upon completion of each elution cycle, the flow through the column is stopped to maintain the relative position of non-eluted

FIG. 2 TypicalInstrument Configuration with Rotary Valves

the column test and sample analysis phases for the instrument configuration in Fig. 1. 8,1.4 Tables 5 and 6 list the conditions that apply during 893

D 5443 H~OQ~N ROW TO Iq.~Tle~la ¢aCUMN

~h~

HEUUM FIOW FOR

HELIUM FLOW FOR

O---I------1-

O

___

SAMPLE murr 8YETEM

INUET EVIITIM

A

r ~ E N

FIG. 7

INDICATES C A R m E l gAE n.OW IS PREEENT . . . . . . .

FU~W

Non-Polar Column Back Flush to the Detector

I I ~ 1 1 I ¢AAmER G A I m O W MI MOT PR4EIIIENT

NOTE--Polar column Is placed in stop flow.

FIG. 4

HYORO4EN FLOW T O PLATINUM COLUMN

End of the "A" Time

H E M U M FLOW FOR POLAR COLUMN I Y ~ I H V ~ O g l N FLOW To PLAI'mUM c o u m u

h~ V

HEUUM Ft.OW FOR

r-

Ih~ V

J I

r" -I.~ "~ . . . . . . .

I~MPI.! INUlT SYET|M

F ~ N,I¢TI~

N Y N ~ E N FLOW

. . . . . . . . .

Row I| PlIE$|ICl

INmC,A T E | c~qJ~mR ~

R O W Ix NOT F ~ E U l C I

NOTE--Second aromatic cut elution from the polar column.

NOTE~First aromatic elution from the polar column.

FIG. 5

INmCA11X c A ~ m e a ~

FIG. 8

Start of the "B" Time

Start of the "C" Time

HVDROOE~ R O W

P ~ . A R COU~I4N I Y l l A I *

. . . . . . . . .

eyelTu

"

JI

FLAME IONIZATION

#'rNoam

FLOW

kX~CATI S ¢ ~ m v l n ~ . . . . . . . . .

~¢,ATE | ¢ ~ n

NOTE--Begln second aromatic elution to the detector.

pLmv I| ~N~T

EUtl PLOW ul NOT P ~ n I [ U T

FIG. 9

NOTE--Begin first aromatic elutlon to the detector. FIG. 6 End of the "B" Time

End of the "C" Time

require that each flow setting and cut time be determined experimentally. 9.2 The carrier gas flow rates, A, B, and C times must be adjusted to produce acceptable analytical performance with the hydrocarbon test mixture in 7.6. These conditions are then recorded and must be used for sample analysis. The system is considered to meet the test method specifications if the hydrocarbon test mixture analysis absolute errors, as calculated in Sections 11 and 12, are equal to or less than the following: +0.3 % per carbon number per hydrocarbon type (for example, C5 paraffins), and ±0.3 % per hydrocarbon class (for example, all paraffins). 9.3 TuningInstrument Conditions with Hydrocarbon Test Mixture: 9.3.1 Configure the system initially as illustrated in Fig. 3. Use the conditions in Tables 3 and 4 for slider valve type

components within the column. For the purpose of simplicity, the three fore-flushes of the polar column will be called the "A," "B," and "C" cuts respectively. The length of time associated with each cut will be called the "A," "B," and "C" times respectively. These times are independent of each other and are a function of instrument configuration, column performance and carrier gas flow conditions. 9. Preparation of Apparatus 9.1 Place the gas chromatograph in service in accordance with the manufacturer's instructions. The initial settings listed in Tables 3 and 4 have been found suitable for slider valve type instruments. The initial settings listed in Tables 5 and 6 have been found suitable for rotary valve type instruments. Variances in column to column performance 894

D 5443 NY~O411N ROW

NYOllOQIN PLOW

1re ~ T I W J I d

T O R,ATINUId ¢OU~klld

GOtJUUU

N | I ~ M Ft,OW FOA ¢~JUMId l W ' A I I

r

HIUCIM ~ FQ~ p OOCUMN I Y I I A n l - - ~ ' ~

.......

O

Nv~n~N

~

mamA1111 Ok~4mlA ~

li|Allll

. . . . . . . . . .

OAill

ROW II lqlUln"

iAl i ~

li |

llllll l lit . . . . . . . . .

FIG. 10 Non-PolarColumn Back Flush to the Detector NYOgOGIN FlOW TO P L M I N U M C O ~ M N

FIG. 13

QAI if|

I|ATII

I A l PLOW IS NOT P H I I I N Y

¢,AR I I ~

II IWIIN'r

Beck Flush of the Non-Polar Column to the Detector

I1~

TABLE 3 HELIUM Fl.l~t/ F ~ I ~

INOfOATII O A I I i ~

.IP.~ .......

¢OUJIdN I V P A I I I

-

.

Temperature Settings, For Slider Valve Instruments

(see Fig. 1)

i t

Device

Final Temperature,

('C)

(°C)

130 130 220 150 100 60

130 130 220 150 430, minimum 280

Polar column Non.polar column Platinum column Detecto¢ Molecular sieve 13X Tenaxs column

SV~M

Y

N W

Initial Temperature,

P,.OW

Rate, (minutes) isothermal isothermal isothermal isothermal 30 -4- 5, logarithmic 1, maximum

FIG. 11 Back Rush of the Polar Column TABLE 4 ~nO~tN

Flow Settings and Cut Times, For Slider Valve Instruments (see Fig. 1)

FLOW

N I I J U U I'¢OW Iq~¢l

Description

t".

COUSMII IIVI'AU "",.-" . . . . . . .

l

'

Helium flow through injection port Helium polar column bypass flow I

Hydrogen flow to platinum column Hydrogen flow through norl-polar column A time B time C time

tNU~ eYIm~

A

IIOiMII

. . . . . . . . .

initial Setting, Acceptable Range, minutes minutes

,'

a i r

OAil I ~

INOiAI'II ¢AJ~IR ~

~

20 mL/min 16 to 23 mL./min same flow rate as injection port flow rate 12 mL/min 10 to 15 ml./min 14 mL/min 12 to 17 mL/min 3.6 2.7 to 4.6 3.4 2.7 to 4.6 3.6 2.7 to 4.6

TABLE 5 Temperature Settings, For Rotary Valve Instruments (see Fig. 2)

I llflllllrr 11 N O r P I ~ | N T

PIG, 12 FinalEIutionto the Non-PolarColumn Device

instruments or Tables 5 and 6 for rotary valve type instruments. 9.3.2 Inject approximately 0.2 ttL of the hydrocarbon test mixture and begin recording the signal from the detector. The sample injection marks the beginning of the A time. Allow paraffins and naphthenes with boiling points below 200"C to elute from the polar column. Retain aromatics, poly-naphthenes, if present, and components boiling above 200"C on the polar column during the A time. If olefins are present in the first elution, they are hydrogenated by the platinum column. All eluting components are trapped on the molecular sieve column. 9.3.3 During the A time, a minimum of 80 % of the dodecane must elute from the polar column. The A time is too short or the A flow is too low if the dodecane elution is less than 80 %. The A time is too long or the A flow is too high if benzene or trans-decalin, or both, elute during the A

Polar column Non-polar column Platinum column Detector Molecular sieve Tenaxs column

Initial Temperature,

Final Temperature,

(°c)

('c)

130 130 170 170 100 60

130 130 170 170 430 280

Rate, minutes Isothermal isothermal Isothermal Isothermal 10°C 1, maximum

time. Adjust the A time or A flow to meet these requirements. 9.3.4 At the end of the A time, change the configuration to that of Fig. 4. Place the polar column in stop flow and program the temperature of the molecular sieve column from 100 to 430"C, minimum, at the rate specified in either Table 3 or Table 5. Components will elute from the molecular sieve column as groups, by carbon number and group type. Within each carbon number group, naphthenes will elute fizst [bllowed by paraffins. If the molecular sieve 895

~[~) D 5443 TABLE 6

Flow Settings end Cut Times, For Rotary Valve Instruments (see Fig. 2) Description

Helium flow through injection port Helium polar column bypass flow Hydrogen flow to platinum column Hydrogen flow through non-polar column A time B time C time

Initial Setting, Acceptable Range, minutes minutes 25 mL/rnin 20 to 35 mL./min same flow rate as Injection port flow rate 7 ml_/min 5 to 10 mL/mln 20 ml_/min 15 to 30 mL/min 2 1.7 to 2.5 2 1.7 to 3.0 2 1.7 to 3.0

column contains a mixture of 13 X and five A types of molecular sieves, the group elution order will be first naphthenes as a group, followed by iso-paraffins as a group and then the normal paraffin, by carbon number. 9.3.5 Upon completion of the naphthene and paraffin elution, change the configuration to that of Fig. 5. Begin cooling the molecular sieve column to 100"C and switch the Tenax 3 column into the A flow to receive the next cut from the polar column. Take the polar column out of stop flow. This marks the beginning of the B time. 9.3.6 During the B time, most, if not all, of the benzene and toluene, some of the Cs aromatics, decalin, naphthenes, and paraffins boiling above 200"C elute to the Tenax 3 column. The B time is too short if all of the trans-decalin does not elute during the B time. The B time is too long if any of the o-Xylene or C9 aromatics elute during the B time. Adjust the B time to meet these requirements. 9.3.7 At the end of the B time, change the configuration to that of Fig. 6. Heat the Tenax 3 column to 280°C and allow all trapped components to elute to the non-polar column. The aromatics and decalin elute from the non-polar column in boiling point order. Naphthenes and paraffins boiling above 200°C do not elute from the non-polar column at this time. 9.3.8 Four minutes and 30 s after the Tenax 3 column begins to heat, change the configuration to that of Fig. 7 and back-flush the non-polar column. Cool the Tenax 3 column to 60"C at this time. Continue the back-flush cycle for 5.5 rain. Back-flush the naphthenes and paraffins boiling above 200°C from the non-polar column to the detector at this time. 9.3.9 At the end of this back-flush cycle, change the configuration to that of Fig. 8. This marks the beginning of the C time. The second cut of aromatics elute from the polar column to the Tenax 3 trap. This elution contains some of the Cs aromatics, approximately one half of the C9 aromatics and a minor amount of C~0 aromatics. Any remaining benzene and most, if not all, of the toluene that did not elute during the B time may elute at this time. Paraffins and naphthenes boiling above 2000C that did not totally elute during the B time may elute now. 9.3.10 The C time is too short if none of the o-Xylene elutes during the C time. The C time is too long if greater than 90 % of the o-Xylene elutes during the C time. 9.3.11 At the end of the C time, change the configuration to that of Fig. 9, place the polar column in stop flow. Heat the Tenax 3 column to 280°C and allow all trapped components to elute to the non-polar column. The aromatics elute from the non-polar column in boiling point order. 896

9.3.12 Four minutes and 30 s after the Tenax 3 trap begins to heat, change the configuration to that of Fig. 10 and back-flush the non-polar column. Cool the Tenax 3 column to 60°C at this time. Continue this back-flush cycle for 5.5 min. Back-flush the naphthenes and paraffins boiling above 200°C from the non-polar column to the detector at this time. 9.3.13 At the end of this back-flush cycle, change the configuration to that of Fig. 11 and back-flush the polar column to the Tenax 3 trap. This back-flush cycle lasts for approximately 10 rain until all remaining components are back-flushed from the polar column to the Tenax 3 column. 9.3.14 At the end of this back-flush cycle, change the configuration to that of Fig. 12. Heat the Tenax 3 column to 280°C and allow all trapped components to elute to the non-polar column. The remaining aromatics with boiling points less than 200°C elute in boiling point order to the detector. 9.3.15 Approximately 6.5 rain after the Tenax 3 column begins to heat, change the configuration to that of Fig. 13 and back-flush the components boiling above 200"C from the non-polar column to the detector. Cool the Tenax 3 column to 60°C and then stop the detector signal data collection. 9.4 Perform the steps outlined in Sections 11 and 12, below, to verify that the system is properly tuned. The system is considered to meet the test method specifications if the hydrocarbon test mixture analysis absolute errors are equal to or less than the following: +0.3 % per carbon number per hydrocarbon type (for example, C5 paraffins), and +0.3 % per hydrocarbon class (for example, all paraffins). 9.5 Record the actual times and temperatures and flows found necessary to meet the separation requirements as described in the various steps of 9.3. Use these parameters for all subsequent sample analyses. 10. Procedure

10.1 Refer to Practice D 4057 for instructions on manual sampling from bulk storage into open containers. Stopper the container immediately after drawing sample. 10.2 Place the instrument in the initial configuration as illustrated in Fig. 3. 10.3 Adjust the operating conditions to those values that were experimentally determined in 9.3 to give the desired separations. This may be done programmatically for automated instruments. 10.4 Inject approximately 0.2 ~tL of sample and begin data acquisition of the detector signal. A chromatogram is required for hydrocarbon type group identification. Integrated peak areas are required for calculations of mass percent. 10.5 Stop the data acquisition after the final cut has been eluted. 11. Calculation 11.1 Identify each hydrocarbon type group by visually matching it with its counterpart in the hydrocarbon test mixture, Fig. 14 and Table 7. The performance characteristics of the molecular sieve column and the sample composition may result in separation of the normal and iso-paraffins

~l~) D 5443 TABLE 7

Hydrocarbon Test Mixture Component Identification

Number Identification 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28

Component Name Cyclopentane n-Pentane Cyclohexane 2,3-Oimethylbutane n-Hexane 1-Hexene Methylcyclohexane 4-Methyl-l-Hexene n-Heptane 1,cis-2-Dimethylcyclohexane 2,2,4-Tdmethylpentane n-Octane 1,cis-2,ds-4-Tflmethylcyclohexane n-Nonane n-Decane n-Undecane n-Dodecane Benzene Toluene (Methylbenzene) trans-Decahydronaphthalene (Oecalin) N-Tetradecane Ethylbenzene 1,2-Dimethylbenzene (o-Xylene) n-Propylbenzene 1,2,4-Tdmethylbenzene 1,2,3-Tdmethylbenzene 1,2,4.5-Tetramethylbenzene Pentamethylbenzene

2S

18 4J

11

(c=. x c.)

+

c.

(~a. x//.) c=.

20 23

'iA li'• le

2

,

i

,

i lO

,

,

,

i

,

FIG. 14

t?

,

,

,

,

,

,

• ,

_,

,

i

,

,

,

SO

,

.

.

'.

SO

A 70

Hydrocarbon Test Mixture

0.85 for the last fraction boiling above 200°C. Use an average response factor of 0.835 for C9 and above aromatics. 11.4 Multiply the area associated with each of the identified groups by the appropriate response factor to produce a c o r r e c t e d area f o r each o f the g r o u p s : Arc = Ai X F i (2) where: A~c = corrected area of an identified group, and A~ = raw area of identified group. 1 1.5 Add all of the individual, corrected areas from 1 1.4. T = 2; A~c (3) where: T = total of corrected areas. 11.6 Divide each of the identified groups by the total corrected area determined in 11.5 to produce the normalized mass percent for each group:

M~=Ai_.£

T where: M~ -- normalized mass percent of an identified group.

(4)

12. Report 12.1 Report the following information: 12.1.1 The mass percent and hydrocarbon group type of each group through C,~ to the nearest 0.01%, 12.1.2 The mass percent of the fraction boiling above 200°C to the nearest 0.01%, 12.1.3 The mass percent of poly-naphthenes boiling below 2000C (for example, trans-Decahydronaphthalene) to the nearest 0.01%, and 12.1.4 The C9 and above aromatics as C9+ aromatics to the nearest 0.01%.

x 0.7487

(1)

where:

F,

2?

lg

12 14

by carbon number. These groups can be combined in the calculations and reported as paraffins, by carbon number. Each of the aromatic components may elute in several of the aromatic fractions. Identify and total each of these components within the appropriate hydrocarbon type group. Peak characteristics will vary and depend on component concentrations in the sample. A qualitative reformer feed may also be used to aid in identification, as in Fig. 15. 11.2 If a computing integrator is used for automatic peak identification, examine the report carefully to ensure that all peaks are properly identified and integrated. 11.3 Response Factors--All groups are reported in mass percent, normalized to 100 %. The following formula is used to calculate the flame ionization detector response factors, as listed in Table 8:

F,=

23

8 , g 10

relative response factor for a hydrocarbon type group of a particular carbon number, = atomic weight of carbon, 12.011,6 C, = number of carbon molecules in the group, Ha, : atomic weight of hydrogen, 1.008, 6 H, -- number of hydrogen molecules in the group, and 0.7487 = corrects the response of methane to unity. Methane will be considered to have a unity (1) response factor. 11.3.1 Use an average response factor of 0.88 for the first three fractions boiling above 200"C. Use a response factor of =

C a w

14. Precision and Bias ~ 14.1 Precision--The precision of any individual measure7 SupportingdataavailablefromASTMHeadquarters.RequestRR:D02-1315. s OV 101 and OV 275 are re~stered trademarks of Ohio ValleySpecialty ChemicalCompany,115 IndustryRoad, Marietta,OH 45750. 9 Chromasorb is a registeredtrademark of Manville Corporation, Box 519, Lompoc,CA 93438.

6 ASTM Publication DS 4B, Physical Constants of Hydrocarbons CI to CIO, ASTM, 1916 Race Street, Philadelphia, PA 19103.

897

~1~ D 5 4 4 3

naphthen~ >200C Type Carbon Number

NIPINI ~ , 6

7

INIPINIP[ 8

9

10

,'~C,

11

FIG. 15

Number of Carbon Atoms

Paraffins

3 4 5 6

0.916 0.906 0.899 0.896

(3:874 0.874

0.811

7

0.692

0.674

0.620

6 9 10 11

0.890 0.888 0.887 0.886

0.874 0.874 0.874 0.874

0.827 0.835 ... ...

.

.

.

.

8,9.10

TABLE 9

Repeatability and Reproducibility for Selected Naphtha Components and Groups of Components

Component or Group

Aromatics .

Aromotlcl

7,8,9

Q u a l i t a t i v e N a p h t h a Sample

TABLE 8 Flame Ionization Detector Response Factors Based on Percentage by Mass of Carbon, Methane Used as Unity Naphthenes

Aromc,~

6,7

. ...

ment resulting from the application of this test method depends on several factors related to the individual or group of components including the volatility, concentration and the degree to which the component or group of components are resolved from closely eluting components or groups of components. As it is not practical to determine the precision of measurement for every component or group of components at different levels of concentration separated by this test method, Table 9 presents the repeatability and reproducibility values for selected, representative components and groups of components. 14.1.1 RepeatabilitymThe difference between successive test results obtained by the same operator and same apparatus under constant operating conditions on identical test materials would, in the long run, in the normal and correct operation of the test method, exceed the repeatability values shown in Table 9 only one case in twenty. 14.1.2 ReproducibilitymThe difference between two

898

Repeatability A

ReWoducibllityA

Benzene

0.0~x)o.m

Toluene

0.051(x)°.aT

0.22(x)o.a7

Ce Aromatl~ Co+ Arornatk= C,v Paraffins Ce Paraffins Co Paraffin8

0.041(x) 0.092(xp.eo 0.005(x)°-s° 0.098(x)o-so

0.17(x) 0.50(x)o.so 0.61 "/, 0.18(x)°.s° 0.17(x)O-SO

Co Naphthenes

0.046(x)°-s°

0.1 l(x)°.5°

C7 Naphthenes Ce Naphtherm Total paraffins Total naphther~ Total aromatics

0.14(x) 0.067(xp.~

0.33(x) 0.13(x) °,as

0.059(x) °-s° 0.077(x) o-so

0.11 (x)°-s° 0.28(x)O~O

0.16 "/,

0.064(x)o.8o

0.~)(x)o=o

0.17(x)O.6O

A (x) Refers to the mass percent of the componentor group of components found.

single and independent test results obtained by different operators working in different laboratories on identical test materials would, in the long run, in the correct operation of this test method, exceed the values shown in Table 9 only one case in twenty. 14.1.3 Bias--Bias is the measurement resulting from the application of this test method cannot be determined since there is no accepted reference material suitable for determining bias. 15. Keywords 15.1 aromatics; gas chromatography; hydrocarbon type; multi-dimensional; naphthenes; paraffins; petroleum distillates

~)

D 5443

ANNEX

(Mandatory Information) A1. CALCULATION AND REPORTING OF LIQUID VOLUME PERCENT A I.I Calculate and report the liquid volume percent of each hydrocarbon type group normalized to 100 %, using the normalized mass percent data as calculated in 12.1 and 12.2 and the average relative density of each hydrocarbon type group from Table A I. I. AI.2 Use an average relative density factor of 0.8000 for the first three fractions boiling above 200"C. Use an average relative density factor of 0.8800 for the last fraction boiling above 200"C. Use an average relative density factor of 0.8762 for (29 and above aromatics. A I.3 Divide each of the hydrocarbon group type mass percent data, as reported in 12.1, 12.2, and 12.3 by the appropriate average relative density factor to produce the corrected liquid volume percent for each of the identified groups:

D,,

(ALl)

where: Vi~ --corrected liquid volume percent of an identified group, M, = normalized mass percent of an identified group, and D a -- average relative density of an identified group. A I.4 Add all of the individual, corrected liquid volume percent data from A 1.2 to produce the total corrected liquid volume percent: T , = Z V~c (AI.2) where: 7", = total corrected liquid volume percent. AI.5 Divide each of the corrected liquid volume percent data for each identified group from AI.3 by the total of the

TABLE A1.1 AverageRelaUve 15/150C Density of Hydrocarbon Type GrouplA Number of Carbon

Atoms

Paraffins

Naphthenes

3 4

0.5070 0.5735

.

.

.

5 6 7 8 , 10

0.6177 o. 22 0.6.11 07143 0.7318 07,26

0.7603 07 8 0.78.8 0.7788 08058 o817.

11

0.7445

0.8200

.

Aromatics .

. ~

_

t

°

B

_

_

0 29 087 0.87 08782 ...

A See Footnote 6.

corrected liquid volume percent data from A1.4 to produce the normalized liquid volume percent for each identified group:

T,

(AI.3)

where: Vi = normalized liquid volume percent of an identified group. AI.6 Report the liquid volume percent and hydrocarbon group type of each group through Cjl to the nearest 0.01%. AI.7 Report the liquid volume percent of the fraction boiling above 200"C to the nearest 0.01%. A1.8 Report the liquid volume percent of the polynaphthenes boiling below 200"C (for example, transDecahydronaphthalene) to the nearest 0.01%. A I.9 Report the liquid volume percent of the C9 and above aromatics as C9+ aromatics to the nearest 0.01%.

The American Society for Testing and Matertals takes no positron respecting the vahdtty of any patent rights asserted m connection with any item mentioned in this standard Users of this standard are expressly advised that determination of the validffy of any such patent rights, and the risk of infringement of such rights, are entirely their own responsiDihty. Thts standard Is subject to revision at any time by the responsible technical committee and must be reviewed every hve years and if not revtsed, etther reapproved or withdrawn. Your comments are mvtted either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments wtll recewe careful consideration at a meeting of the responstble technical committee, which you may attend If you feel that your comments have not received a raft hearing you should make your views known to the ASTM Commtttee on Standards, 100 Barr Herbor Dnve, West Conshohocken, PA 19428

899

~[~

Designation: D 5453 - 93 Standard Test Method for Determination of Total Sulfur in Light Hydrocarbons, Motor Fuels and Oils by Ultraviolet Fluorescence 1 This standard is issued under the fixed designation D 5453; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (¢) indicates an editorial change since the last revision or reapproval.

4. Significance and Use

1. Scope 1.1 This test method covers the determination of total sulfur in liquid hydrocarbons, boiling in the range from approximately 25"C to 400°C, with viscosities between approximately 0.2 and 10 cSt (mm2/S) at room temperature. This test method is applicable to naphthas, distillates, motor fuels and oils containing 1.0 to 8000 mg/kg total sulfur. 1.2 This test method is applicable for total sulfur determination in liquid hydrocarbons containing less than 0.35 % (m/m) halogen(s). 1.3 SI (Metric) units are regarded as standard. 1.4 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. See 3.2, 6.3, 6.4, 8.1 and Section 7.

4.1 Some process catalysts used in petroleum and chemical refining can be poisoned when trace amounts of sulfur bearing materials are contained in the feedstocks. This test method can be used to determine sulfur in process feeds and can also be used to control sulfur in finished products.

2. Referenced Documents

2.1 ASTM Standards: D 4057 Practice for Manual Sampling of Petroleum and Petroleum Products 2 D 4177 Practice for Automatic Sampling of Petroleum and Petroleum Products 2 3. Summary of Test Method 3.1 A hydrocarbon sample is directly injected or placed in a sample boat. The sample or boat, or both, enter into a high temperature combustion tube where the sulfur is oxidized to sulfur dioxide (SO2) in an oxygen rich atmosphere. Water produced during the sample combustion is removed and the sample combustion gases are next exposed to ultraviolet (UV) light. The SO2 absorbs the energy from the UV light and is converted to excited sulfur dioxide (SO2"). The fluorescence emitted from the excited SO2' as it returns to a stable state SO2 is detected by a photomultiplier tube and the resulting signal is a measure of the sulfur contained in the

sample. NOTE 1: Warning--Exposure to excessive quantities of ultraviolet (UV) light is injurious to health. The operator must avoid exposingany part of their person, especiallytheir eyes,not only to direct UV light but also to secondaryor scattered radiation that is present. J This test method is under the jurisdiction of ASTM Committee D-02 on Petroleum Products and Lubricants and is the direct responsibility of Subeom. mittee I:)02.030(3 on Eleetrometric Methods. Current edition approved Sept. 15, 1993. Published November 1993. 2 Annual Book of ASTM Standards, Vol 05.02.

5. Apparatus 3 5.1 Furnace--An electric furnace held at a temperature (1100"C) sufficient to pyrolyze all of the sample and oxidize sulfur to SO2. 5.2 Combustion Tube--A quartz combustion tube constructed to allow the direct injection of the sample into the heated oxidation zone of the furnace or constructed so that the inlet end of the tube is large enough to accommodate a quartz sample boat. The combustion tube must have side arms for the introduction of oxygen and carrier gas. The oxidation section shall be large enough (see Figs. 1 and 2) to ensure complete combustion of the sample, Figs. 1 and 2 depict conventional combustion tubes. Other configurations are acceptable if precision is not degraded. 5.3 Flow ControlmThe apparatus must be equipped with flow controllers capable of maintaining a constant supply of oxygen and carrier gas. 5.4 Drier Tube--The apparatus must be equipped with a mechanism for the removal of water vapor. The oxidation reaction products include water vapor which must be eliminated prior to measurement by the detector. This can be accomplished with a membrane drying tube, permeation dryer, that utilizes a selective capillary action for water removal. 5.5 V Z Fluorescence Detector--A qualitative and quantitative detector capable of measuring light emitted from the fluorescence of sulfur dioxide by UV light. 5.6 Microlitre Syringe--A microlitre syringe capable of accurately delivering 5 to 20-microlitre quantities. The needle should be 50 mm (:1:5 ram) long. 5.7 Sample Inlet System--Either of two types of sample inlet systems can be used. 5.7.1 Direct Injection--A direct injection inlet system must be capable of allowing the quantitative delivery of the material to be analyzed into an inlet carrier stream which directs the sample into the oxidation zone at a controlled an~! repeatable rate. A syringe drive mechanism which discharges the sample from the microlitre syringe at a rate of approximately 1 ~tL/s is required. See example, Fig. 3. s Apparatus manufactured in several variations by Antek Instruments, Inc., Houston, TX has been found suitable for this purpose.

900

~

D 5453 450ram

~

'. ~ "

12ram

,-n

/-

P " - " 50ram 100ram

See DETAIL BELOW

~A;,~,;,~; T M ,°

~ •

~J

~1

I~

'~'~

ID MUST FIT 12ram $EPTUM

t2rnm ~q" 25ram

BURNER TIP AND SEPTUM DETAILS

Direct Inject

FIG. 1

r

6g ~.mm

I

T M

:1

from OO x 2ram ID

6ram 00 x 2ram IO

-1111 U

6|mmO /

FIG. 2 Boat Inlet

- INLET- CARRIER/OXYGEN / ~ j ' ~ DIRECT INJECT PYROTUBE

SYRINGE

DRIVE PYRO

FIG. 3 Syringe Drive, Direct Injection 901

(~) D 5453

i/

FURNACE

~

INIET-CARRIER~"~)XYGE mNa'/~

BOATDRIVE

FIG. 4 BoatInlet System 5.7.2 Boat Inlet System--An extended combustion tube provides a seal to the inlet of the oxidation area and is swept by a cartier gas. The system provides an area to position the sample carrying mechanism (boat) at a retracted position removed from the furnace. The boat drive mechanism will fully insert the boat into the hottest section of the furnace inlet. The sample boats and combustion tube are constructed of quartz. The combustion tube provides a coolant jacket for the area in which the retracted boat rests awaiting sample introduction from a microlitre syringe. A drive mechanism which advances and withdraws the sample boat into and out of the furnace at a controlled and repeatable rate is required. See example, Fig. 4. 5.8 Refrigerated CirculatorDAn adjustable apparatus capable of delivering a coolant material at a constant temperature as low as 4"C could be required when using the boat inlet injection method (optional). 5.9 Strip Chart Recorder, (optional). 5.10 Balance with a Precision of +O.01 mg, (optional).

lessening the accuracy of the determination. 6.2 Inert Gas--Argon or helium only, high purity grade (that is, chromatography or zero grade), 99.998 % rain purity, moisture 5 ppm w/w max. 6.3 Oxygen--High purity (that is, chromatography or zero grade), 99.75 % rain purity, moisture 5 ppm w/w max, dried over molecular sieves. NOTE 2: Warning--Vigorously accelerates combustion. 6.4 Toluene, Xylenes, Isooctane, Reagent grade. (Other solvents similar to those occurring in samples to be analyzed are also acceptable.) Correction for sulfur contribution from solvents (solvent blank) used in standard preparation and sample specimen dilution is required. Alternatively, use a solvent with nondetectable sulfur contamination relative to the sample unknown makes the blank correction unnecessary. NoTE 3: Warnhag--Flammable solvents. 6.5 Dibenzothiophene, FW184.26, 17.399 % (m/m) S (Note 4). 6.6 Butyl Suede, FW146.29, 21.92 70 (m/m) S (Note 4). 6.7 Thionaphthene (Benzothiophene), FW134.20, 23.90 70 (m/m) S (Note 4). NOTE 4--A correction for chemical impurity can be required. 6.8 Quartz Wool: 6.9 Sulfur Stock Solution, 1000 gg S/mL--Prepare a stock solution by accurately weighing 0.5748 g of dibenzothiophene or 0.4652 g of Butyl Sulfide or 0.4184 g of thionaphthene into a tared 100 mL volumetric flask. Dilute to volume with selected solvent. This stock can be further diluted to desired sulfur concentration (Note 5). NOTE 5mWorking standards should be remixed on a regular basis depending upon frequency of use and age. Typically, stock solutions have a usefullife of about 3 months.

6. Reagents

6.1 Purity of ReagentsDReagent grade chemicals shall be used in tests. Unless otherwise indicated, it is intended that all reagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, where such specifications are available. 4 Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without 4 Reagent Chemicals, American Chemical Society Specifications, American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed by the American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Peele, Dorset, U.K., and the United States Pharmacopeia and National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville, MD.

902

~ O5453 7. Hazards 7.1 High temperature is employed in this test method. Extra care must be exercised when using flammable materials near the oxidative pyrolysis furnace. 8. Sampling 8.1 Obtain a test unit in accordance with Practice D 4057 or Practice D 4177. To preserve volatile components which are in some samples, do not uncover samples any longer than necessary. Samples should be analyzed as soon as possible after taking from bulk supplies to prevent loss of sulfur or contamination due to exposure or contact with sample container. NOTE 6: Warning--Samples that are collectedat temperatures below room temperature can undergo expansion and rupture the container. For such samples, do not fill the container to the top; leavesufficientair space abovethe sample to allow room for expansion. 8.2 If the test unit is not used immediately, then thoroughly mix in its container prior to taking a test specimen. 9. Preparation of Apparatus 9.1 Assemble and leak check apparatus according to manufacturer's instructions. 9.2 Adjust the apparatus, dependent upon the method of sample introduction, to meet conditions described in Table 1. 9.3 AdJust instrument sensitivity, baseline stability and perform instrument blanking procedures following manufacturer's guidelines. 10. Calibration and Standardization 10.1 Select one of the suggested curves outlined in Table 2. Prepare a series of calibration standards by making dilutions of the stock solution to cover the range of operation and consisting of sulfur type and matrix similar to samples to be analyzed. 10.2 Flush the microlitre syringe several times with the sample prior to analysis. If bubbles are present in the liquid column, flush the syringe and withdraw a new sample. 10.3 A sample size recommended for the curve selected from Table 2 must be quantitatively measured prior to injection into the combustion tube or delivery into the sample boat for analysis (Note 6). There are two alternative techniques available. TABLE 1

TABLE 2

10.5 Calibrate the instrument using one of the following two techniques. 10.5.1 Perform measurements for the calibration standards and blank using one of the procedures described in Sections 10.2 through 10.4. Measure the calibration standards and blank three times. Subtract the average blank response from each standard measurement before determining the average integrated response (see 6.4). Construct a curve plotting average integrated detector response (y=axis) versus pg sulfur injected (x-axis). This curve should be linear and system performance must be checked with the calibration standards at least once per day. 10,5,2 If the apparatus features an internal calibration routine, measure the calibration standards and blank three

Sulfur Standards

Curve II Sulfur ng/gL.

Curve Ul Sulfur ng/p.L

0.50 2.50 5.00

5.00 25.00 50.00 100.00 Injection Size 5-10 pL

100.00 500.00 1000.00

Injection Size 10-20 pL

NOTE 8--Slowing boat speed or briefly pausing the boat in the

1 p,L/s 140-160 mm/mln 1100" + 25°C 450-500 cc/min 10-30 cc/min 130-160 cc/min

Curve I Sulfur ng/~L

10.3.2 Fill the syringe as described in 10.3.1. Weigh the device before and after injection to determine the amount of sample injected. This procedure can provide greater precision than the volume delivery method, provided a balance with a precision of +0.01 mg is used. 10.4 Once the appropriate sample size has been measured into the microlitre syringe, promptly and quantitatively deliver the sample into the apparatus. Again, there are two alternative techniques available. 10.4.1 For direct injection, carefully insert the syringe into the inlet of the combustion tube and the syringe drive. Allow time for sample residues to be burned from the needle (Needle Blank). Once a stable baseline has reestablished, promptly start the analysis. Remove syringe once the apparatus has returned to a stable baseline. 10.4.2 For the boat inlet, quantitatively discharge the contents of the syringe into the boat containing quartz wool at a slow rate being careful to displace the last drop from the syringe needle. Remove the syringe and promptly start the analysis. The instrument baseline should remain stable until the boat approaches the furnace and vaporization of the sample begins. Instrument baseline is to be restablished before the boat has been completely withdrawn from the furnace (Note 8). Once the boat has reached its fully retracted position, allow one rain for cooling before the next sample injection (Note 9). furnace can be necessaryto assure complete sample combustion. NOTe 9--The level of boat cooling r~uired and the onset of sulfur detection followingsample injection are directly related to the volatility of the materials analyzed. The use of a refrigerated circulator to minimize the vaporization of the sample until the boat begins approaching the furnace could be required.

Typical Operating Conditions

Syringe Drive (Direct Inject) Drive Rate (700-750) Boat Drive (Boat Inlet) Drive Rate (700-750) Furnace Temperature Furnace Oxygen Flowmeter Setting (3.8-4.1) Inlet Oxygen Fiowmeter Setting (0.4-0.8) Inlet Carrier Flowmeter Setting (3.4-3.6)

NOTe 6--Injection of a constant or similar sample size for all materials analyzed in a selected operating range promotes consistent combustion conditions. 10.3.1 The volumetric measurement of the injected material can be obtained by filling the syringe to the selected level. Retract the plunger so that air is aspirated and the lower liquid meniscus falls on the I0 % scale mark and record the volume of liquid in the syringe. After injection, again retract the plunger so that the lower liquid meniscus falls on the 10 % scale mark and record the volume of liquid in the syringe. The difference between the two volume readings is the volume of sample injected (Note 7). NOTE 7--An automatic sampling and injection devicecan be used in place of the describedmanual injvction procedure.

Injection Size 5 p.L

903

~

D 5453

times using one of the procedures described in Sections 10.2 through 10.4. If blank correction is required and is not available (see 6.4), calibrate the analyzer as per manufacturer's instructions using the average response for each standard versus ng of sulfur. This curve should be linear and system performance must be checked with the calibration standards at least once per day. 10.6 If analyzer calibration is performed using a different calibration curve than listed in Table 2, select an injection size based on the curve closest in concentration to the measured solution(s) (Note 10). NOTE lO--Injection of 10 gL of the 100 ng/~tL standard would establish a calibration point equal to I000 ng or 1.0 gg. 11. Procedure 11.1 Obtain a test specimen using the procedure described in Section 8. The sulfur concentration in the test specimen must be less than the concentration of the highest standard and greater than the concentration of the lowest standard used in the calibration. If required, a dilution can be performed on either a weight or volume basis. 11.1.1 Gravimetric Dilution--Record the mass of the test specimen and the total mass of the test specimen and solvent. 11.1.2 Volumetric DilutionmRecord the mass of the test specimen and the total volume of the test specimen and solvent. 11.2 Measure the response for the test specimen solution using one of the procedures described in Sections 10.2 through 10.4. 11.3 Inspect the combustion tube and other flow path components to verify complete oxidation of the test specimen. 11.3.1 Direct Inject SystemsmReduce the sample size or the rate of injection, or both, of the specimen into the furnace if coke or sooting is observed. 11.3.2 Boat Inlet Systems--Increase the residence time for the boat in the furnace if coke or soot is observed on the boat. Decrease the boat drive introduction rate or specimen sample size, or both, if coke or soot is observed on the exit end of the combustion tube.

11.3.3 Cleaning and Recalibration--Clean any coked or sooted parts per manufacturer's instructions. After any cleaning or adjustment, assemble and leak check the apparatus. Repeat instrument calibration prior to reanalysis ofthe test specimen. 11.4 Measure each test specimen solution three times and calculate the average detector responses.

( I - Y)

SxMxK,

(3)

G Sulfur, ppm ~tg/g) - V x D × g/1000 mg

(4)

or,

where: D ffi density of test specimen solution, mg/p.L (neat injection), or concentration of solution, mg/p.L (volumetric dilute injection), Ks = gravimetric dilution factor, mass of test specimen/mass of test specimen and solvent, g/g, M = mass of test specimen solution injected, either measured directly or calculated from measured volume injected and density, V × D, mg, V ffi volume of test specimen solution injected, either measured directly or calculated from measured mass injected and density, M/D, ttL, G -- sulfur found in test specimen, ~tg.

13.1 Repeatability--The difference between two test resuits obtained by the same operator with the same apparatus under constant operating conditions on identical test material would, in the long run, in the normal and correct operation of the test method, exceed the following values in only I ease in 20, where x ffi the average of the two test results. r - 0.1867(x) (°.6~)

(I)

or, (I- Y) Sulfur,ppm (~tg/g)= S x v x Kv

O Sulfur, ppm (ttg/g) - M × Ks × g/1000 mg

13. Precision

12. Calculation 12.1 For analyzers calibrated using a standard curve, calculate the sulfur content of the test specimen in parts per million (ppm) as follows: Sulfur, ppm (~tg/g)=

where: D ffi density of test specimen solution, g/mL, I = average of integrated detector response for test specimen solution, counts, Ks-- gravimetrie dilution factor, mass of test specimen/mass of test specimen and solvent, g/g, Kv= volumetric dilution factor, mass of test specimen/ volume of test specimen and solvent, g/mL, M = mass of test specimen solution injected, either measured directly or calculated from measured volume injected and density, V x D, g, S ffi slope of standard curve, counts/gg S, V -- volume of test specimen solution injected, either measured directly or calculated from measured mass injected and density, M/D, ttL, and Y = y-intercept of standard curve, counts. 12.2 For analyzers calibrated using internal calibration routine without blank correction, calculate the sulfur of the test specimen in parts per million (ppm) as follows:

(2)

(5)

13.2 ReproduciblTity--The difference between two single and independent results obtained by different operators working in different laboratories on identical test material would, in the long run, in the normal and correct operation ofthe test method, exceed the following values in only I case in 20, where x ffi the average of the two test results, R .. 0.2217(x)t°.92) (6) 13.3 Bias--The bias of this method was determined in a

904

~1~ D 5453 on the SRMs were within the repeatability of the test method. 13.4 Examples of the above precision estimates for selected absolute values of x are set out in Table 3.

1992 research report, 5 by analysis of standard reference materials (SRMs) containing known levels of sulfur in hydrocarbon. This report indicated that the results obtained

14. Keywords 14.1 fluorescence; sulfur; ultraviolet

5 Supporting data available from ASTM Headquarters. Request RR:D02-1307.

TABLE 3 Concentration (mg/kg S) 1 5 10 50 1 O0 500 1000 5000

Repeatability (r) and Reproducibility (R) ~,

r

R

0.187 0.515 0.796 2.195 3.397 9.364 14.492 39.948

0.222 0.975 1.844 8.106 15,338 07,425 127,575 560,813

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users el this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reepproved or withdrawn. Your comments are Invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at e meeting of the reSponsible technical committee, which you may attend. If you feel that your comments have not received e fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103.

905

(~l~ Designation: D 5454 - 93 Standard Test Method for Water Vapor Content of Gaseous Fuels Using Electronic Moisture Analyzers 1 This standard is issued under the fixed designation D 5454; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (4) indicates an editorial change since the last revision or reapproval.

1. Scope 1.1 This test method covers the determination of the water vapor content of gaseous fuels by the use of electronic moisture analyzers. Such analyzers commonly use sensing cells based on phosphorus pentoxide, P205, aluminum oxide, A1203, or silicon sensors. 1.2 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate sofety and health practices and determine the applicability of regulatory limitations prior to use.

3.1.4 water dewpoint--the temperature (at a specified pressure) at which liquid water will start to condense from the water vapor present. Charts of dewpoints versus pressure and water content are found in Test Method D 1142.

4. Significance and Use 4.1 Water content in fuel gas is the major factor influencing internal corrosion. Hydrates, a semisolid combination of hydrocarbons and water, will form under the proper conditions causing serious operating problems. Fuel heating value is reduced by water concentration. Water concentration levels are therefore frequently measured in natural gas systems. A common pipeline specification is 4 to 7 lb/ MMSCF. This test method describes measurement of water vapor content with direct readout electronic instrumentation.

2. Referenced Documents

2.1 A S T M Standards: D 1142 Test Method for Water Vapor Content of Gaseous Fuels by Measurements of Dew-Point Temperature 2 D 1145 Method of Sampling Natural Gas 3 D 4178 Practice for Calibrating Moisture Analyzers4 D4888 Test Method for Water Vapor In Natural Gas Using Length-of-Stain Detector Tubes 2 3. Terminology 3.1 Description of Terms Specific to This Standard: 3.1.1 capacitance type cell--this cell uses aluminum coated with AI203 as part of a capacitor. The dielectric AI20 a film changes the capacity of the capacitor in relation to the water vapor present. Unlike P205 cells, this type is nonlinear in its response. If silicon is used instead of aluminum, the silicon cell gives improved stability and very rapid response. 3.1.2 electrolytic type cellmthis cell is composed of two noble metal electrode wires coated with P205. A bias voltage is applied to the electrodes, and water vapor chemically reacts, generating a current between the electrodes proportional to the water vapor present. 3.1.3 water content--water content is customarily expressed in terms of dewpoint, OF or °C, at atmospheric pressure, or the nonmetric term of pounds per million standard cubic feet, Ib/MMSCF. The latter term will be used in this test method because it is the usual readout unit for electronic analyzers. One Ib/MMSCF = 2 I. 1 ppm by volume or 16.1 mgm/m 3 of water vapor. Analyzers must cover the range 0.1 to 50 Ib/MMSCF.

5. Apparatus 5.1 The moisture analyzer and sampling system will have the following general specifications: 5.1.1 Sampling SystemmMost errors involved with moisture analysis can be eliminated with a proper sampling system. 5.1.1.1 A pipeline sample should be obtained with a probe per Method D 1145. The sample temperature must be maintained 2°C (3OF) above the dewpoint of the gas to prevent condensation in the sample line or analyzer. Use of insulation or heat tracing is recommended at cold ambient temperatures. 5.1.1.2 Analyzer sensors are very sensitive to contamination. Any contaminants injurious to the sensor must be removed from the sample stream prior to reaching the sensor. This must be done with minimum impact on accuracy or time of response. If the contaminant is an aerosol of oil, glycol, etc., a coalescing filter or semipermeable membrane separator must be used. 5.1.2 ConstructionmSampling may be done at high or low pressure. All components subject to high pressure must be rated accordingly. To minimize diffusion and absorption, all materials in contact with the sample before the sensor must be made of stainless steel. Tubing of I/8 in. stainless steel is recommended. NOTE h P r e c a u t i o n - - U s e appropriate safety precautions when sampling at high pressure.

i This test method is under the jurisdiction of ASTM Committee D-3 on Gaseous Fuels and is the direct responsibility of Subcommittee D03.05 on Determination of Special Constituents of Gaseous Fuels. Current edition approved Sept. 15, 1993. Published November 1993. 2 Annual Book of ASTM Standards, Vol 05.05. 3 Discontinued--See 1986 Annual Book of ASTM Standards, Vol 05.05. 4 Annual Book of ASTM Standards, Vol 05.02.

5.1.2.1 Pressure gages with bourdon tubes should be avoided due to water accumulation in the stagnant volume. 5.1.2.2 Sample purging is important to satisfactory response time. There must be a method to purge the sample line and sample cleanup system. 906

~

O 5454

BACK PRESSURE

C.~AS IN LE'r

SHUTOFF

~.

J

AN.aJ,.Y~,JER )

i

HIGH PRF..~$URE

ICEANATERMIXTURE32"F

N__

•

Flow Diagram FIG. 1 Moisture Calibrator

5.1.3 ElectronicsmOutput from the sensor will be linearized for analog or digital display in desired units (usually Ib/MMSCF). There must be an adjustment for calibration accuracy available that can be used in the field if a suitable standard is available. (This does not apply to instruments that assume complete chemical reaction of water. Their accuracy still must be verified as in Section 6.) 5.1.4 Power Supply--Analyzers for field use will have rechargeable or easily replaceable batteries.

established by tube weight loss. 6.4 Compressed gas water vapor standards may be used, provided they are checked by an independent method once a month. 6.5 Calibrate the analyzer using one of the standards in 6.3 and 6.4 and respective procedures. Calibration must be at two points, one higher and one lower than average expected readings. Some analyzers can have large nonlinear errors. Use the calibration adjustment if applicable.

NOTE 2: Caution~Analyzersfor use in hazardouslocationsbecause of combustible gas must be certified as meeting the appropriate

7. Procedure

7.1 Preparation--The analyzer operation and calibration should be checked according to the manufacturer's recommendations prior to use. See Section 6. Verification of a dry instrument using dry compressed nitrogen to get a reading below 1 Ib/MMSCF is recommended prior to field use. 7.2 Sample Procedure--Sample as in paragraph 5.1.1.1. Use as short a sample line as practical. Purge the sample for 2 min before valving to the sensor. 7.3 Reading--The time for a sensor to come to equilibrium is variable depending on its type and condition. The analyzer may require 20 rain to stabilize. Some analyzers have an external recorder output, and these can be used with a chart recorder to become familiar with the true equilibrium response time.

requirements. 6. Calibration 6.1 A calibration technique is described in Practice D 4178 that should be used to verify the accuracy of the analyzer. This method uses the known vapor pressure of water at 0°C and mixes wet gas and dry gas to make up the total pressure so that a standard gas of known water concentration is achieved. 6.1.1 Instruments very sensitive to sample flow must be compensated for barometric pressure. 6.2 A commercially made water vapor calibrator is shown in Fig. 1, which uses essentially the same technique. This method is useful only between 5 to 50 Ib/MMSCF. 6.3 Low range water vapor standards may be obtained by the use of water permeation tubes. Permeation rates must be

8. Precision and Bias 8.1 Precision data is being prepared for this test method

by an interlaboratorystudy.

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility.' This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reepproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responaibie technical committee, which you may attend, if you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103.

907

~)

Designation:D 5482 - 96 Standard Test Method for Vapor Pressure of Petroleum Products (Mini Method-Atmospheric) 1 This standard is issued under the fixed designation D 5482; the number immedialely following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (0 indicates an editorial change since the last revision or reapproval.

1. Scope 1.1 This test method provides a procedure for the determination of total vapor pressure of petroleum products using automatic vapor pressure instruments. The test method is suitable for testing samples with boiling points above 0*C (32*F) that exert a vapor pressure between 7 and 110 kPa (1.0 and 16 psi) at 37.8*C (100*F) at a vapor-to-liquid ratio of 4:1. The test method is applicable to gasolines containing oxygenates. No account is made of dissolved water in the sample.

D 5190 Test Method for Vapor Pressure of Petroleum Products (Automatic Method)a D 5191 Test Method for Vapor Pressure of Petroleum Products (Mini Method) a 3. Terminology 3.1 Definitions of Terms Specific to This Standard: 3.1.1 dry vapor pressure equivalent (DVPE)--a value calculated by a correlation equation (see 13.2) from the total pressure, 3. I. I. l Discussion--The DVPE is expected to be equivalent to the value obtained on the sample by Test Method D 4953. 3.1.2 total pressure--the observed pressure measured in the experiment that is the resultant pressure increase from the initial ambient atmospheric pressure.

NOTE l - - B e c a u s e the external atmospheric pressure does not influence the resultant vapor pressure, this vapor pressure is an absolute pressure at 37.8°C (100"F) in kPa (psi). This vapor pressure differs from the true vapor pressure o f the sample due to some small vaporization o f the sample and dissolved air into the air o f the confined space.

1.2 This test method is a modification of Test Method D 5191 (Mini Method) where the test chamber is at atmospheric pressure prior to sample injection. 1.3 This test method covers the use of automated vapor pressure instruments that perform measurements on liquid sample sizes in the range from 1 to 10 mL. 1.4 This test method is suitable for the determination of the dry vapor pressure equivalent (DVPE) of gasoline and gasoline-oxygenate blends by means of a correlation equation (see 13.2). The calculated DVPE is considered equivalent to the result obtained on the same material when tested by Test Method D 4953. 1.5 The values stated in acceptable SI units are regarded as standard. The values given in parentheses are provided for information only. 1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. (For specific hazard statements, see Note 3.)

4. Summary of Test Method 4.1 A known volume of chilled, air-saturated sample is introduced into a thermostatically controlled test chamber, the internal volume of which is five times that of the total test specimen introduced into the chamber. The test chamber is at atmospheric pressure prior to introduction of the sample. After introduction of the sample into the test chamber the test specimen is allowed to reach thermal equilibrium at the test temperature, 37.8°C (100*F). The resulting rise in pressure in the chamber is measured using a pressure transducer sensor and indicator. 4.2 The measured total vapor pressure is converted to a dry vapor pressure equivalent (DVPE) by use of a correlation equation (see 13.2). 5. Significance and Use 5.1 Vapor pressure is an important physical property of volatile liquids. 5.2 Vapor pressure is critically important for both automotive and aviation gasolines, affecting starting, warm-up, and tendency to vapor lock with high operating temperatures or high altitudes. Maximum vapor pressure limits for gasoline are legally mandated in some areas as a measure of air pollution control.

2. Referenced Documents 2.1 A S T M Standards: D4057 Practice for Manual Sampling of Petroleum and Petroleum Products2 D4953 Test Method for Vapor Pressure of Gasoline and Gasoline-Oxygenate Blends (Dry Method)3

6. Apparatus 6.1 Vapor Pressure Apparatus--The type of apparatus4 suitable for use in this test method employs a small volume

t This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum products and Lubricants and is the direct responsibility of Subcommittee 1302.08.O1) on RVP and V/L Ratio. Current edition approved June 10, 1996. Published August 1996. Originally published as D 5482 - 93. Last previous edition D 5482 - 93. 2 Annual Book of ASTM Standards, Vo105.02. 3 Annual Book of ASTM Standards, Vol 05.03.

4 The following instruments have been found satisfactory for use in this test procedure as determined by interlaboratory testing: Herzog Mini Reid Vapor PrematureModel MP970--available from Walter Herzog OmbH, Lauda, Germany and UIC, Inc., Joliet, IL, and ABB Model 4100---avalisble from ABB Process Analyti~ Lewisburg, WV.

908

i ~ D 5482 test chamber incorporating a transducer for pressure measurements and associated equipment for thermostatically controlling the chamber temperature. 6.1.1 The test chamber shall be designed to contain between 2 and 50 mL of liquid and vapor and be capable of maintaining a vapor-liquid ratio between 3.95 to 1.00 and 4.05 to 1.00. 6.1.2 The pressure transducer shall have a minimum operational range from 0 to 172 kPa (0 to 25.0 psi) with a minimum resolution of 0.1 kPa (0.01 psi) and a minimum accuracy of :1:0.3 kPa (±0.05 psi). The pressure measurement system shall include associated electronics and readout devices to display the resulting pressure reading. 6.1.3 A thermostatically controlled heater shall be used to maintain the test chamber at 37.8 ± 0.1*C (100 + 0.2*F) for the duration of the test. 6.1.4 A platinum resistance thermometer shall be used for measuring the temperature of the test chamber. The minimum temperature range of the measuring device shall be from ambient to 75°C (167*F) with a resolution of 0.1*C (0.2*F) and accuracy of 0. I*C (0.2*F). 6.1.5 The vapor pressure apparatus shall have provisions for introduction of the test specimen into the test chamber and for the cleaning or purging of the chamber following the test. 6.2 Syringe, if required, gas fight, 1 to 20 mL capacity with a ± 1 % or better accuracy and a + 1 % or better precision. The capacity of the syringe shall not exceed two times the volume of the test specimen being dispensed, and shall be chosen so as to provide maximum accuracy and resolution for the volume to be injected. 6.3 Iced-Water Bath or Air Bath, for chilling the Samples and syringe to temperatures between 0 and I*C (32 to 34"F). 6.4 Mercury Manometer, for calibration of the pressure transducer, shall include the range from 0 to 130 kPa (0 to 19 psi). The manometer scale shall be graduated in increments of 0.2 kPa (0.03 psi), nominally. 6.5 Pressure Source, clean, dry compressed gas or other suitable compressed air capable of providing pressure for calibration of the transducer and cleaning of the cell.

7.4 7.5 7.6 7.7

2,2.Dimethylbutane (Warning--See Note 3.) "2,3-Dimethylbutane (Warning--See Note 3.) 2.Methylpentane (Warning--See Note 3.) Toluene (Warning--See Note 3.)

NOTE 3:

Warning--~clohexane,

toluene,

cyclopentane,

2,2-

dimethylbutane, 2,3-dimethylbutane and 3-methylpentane are flammable and a health hazard. 8. Sampling 8.1 GeneralRequirements: 8.1.1 The extreme sensitivity of vapor pressure measurements to losses through evaporation and the resulting changes in composition is such as to require the utmost precaution and the most meticulous care in the handling of samples.

8.1.2 Obtain a sample and test specimen in accordance with 10.3 of Practice D 4057, except do not use 10.3.1.8 of Practice D 4057, Sampling by Water Displacement, for fuels containing oxygenates. Use a I-L (l-qt) sized container Idled between 70 to 80 % with sample. 8.1.3 Perform the vapor pressure determination on the first test specimen withdrawn from a sample container. Do not use the remaining sample in the container for a second vapor pressure determination. If a second determination is necessary, obtain a new Sample. 8.1.4 Protect samples from excessive temperatures prior to testing. This can be accomplished by storage in an appropriate ice bath or refrigerator. 8.1.5 Do not test Samples stored in leaky containers. Discard and obtain a new sample if leaks are detected. 8.1.6 Do not store Samples in plastic (polyethylene, polypropylene, etc.) containers, since volatile materials may diffuse through the walls of the container. 8.2 Sampling Temperature--Cool the sample container and contents in an ice bath or refrigerator to the 0 to I°C (32 to 34*F) range prior to opening the sample container. Allow sufficient time to reach this temperature. Verify the sample temperature by direct measurement of the temperature of a similar liquid in a similar container placed in the cooling bath or refrigerator at the same time as the Sample. 8.3 Verification of Sample Container Filling--After the sample reaches thermal equilibrium at 0 to I oc, take the container from the cooling bath or refrigerator, wipe dry with an absorbent material and unseal. Using a suitable gage, confirm that the sample volume equals 70 to 80 volume % of the container capacity. 8.3.1 Do not perform a vapor pressure test on the sample if the container is filled to less than 70 volume % of the container capacity. 8.3.2 If the container is more than 80 volume % full, pour out enough Sample to bring the container contents within the 70 to 80 volume % range. Do not return any sample to the container once it has been withdrawn. 8.4 Air Saturation of Sample in Sample Container: 8.4.1 With the sample again at a temperature of 0 to l'C, take the container from the cooling bath or refrigerator, wipe it dry with an absorbent material, unseal it momentarily, taking care that no water enters, reseal and shake it vigorously. Return it to the bath or refrigerator for a minimum of 2 rain. 8.4.2 Repeat 8.4.1 twice more. Return the Sample to the

N o t e 2 - - A vacuum source is an alternate means for cleaning of the cell.

7. Reagents and Materials

7.1 Purity of Reagents--Use chemicals of at least 99 % purity for quality control checks (Section 11). Unless otherwise indicated, it is intended that all reagents conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society where such specifications are available? Lower purities can be used, provided it is fast ascertained that the reagent is of sufficient purity to permit its use without lessening the accuracy of the determination. 7.2 Cyclohexane (Warning--See Note 3.) 7.3 Cyclopentane(Warning--See Note 3.) 5 Reagent Chemicals, American Chemical Society Specifications, American Chemical Society, Washington, DE. For suggestions on the testing of reagents not listed by the American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), RockviUe, MD.

909

¢ ~ D 5482 bath or refrigerator until the beginning of the procedure. 8.5 Verification of Single Phase--After drawing a test specimen and injecting it into the instrument for analysis, check the remaining sample for phase separation. When the sample is contained in a @ass container, this observation can be made prior to sample transfer. When the sample is contained in a non-transparent container, mix the sample thoroughly and immediately pour a portion of the remaining sample into a glass container and observe for evidence of phase separation. When the sample is not clear and bright or when a second phase is observed, discard the test and the sample.

vapor pressures, as found in A S T M DS4B, 6 include: cyclopentane, 68.3 Ida (9.91 psi);2,2-dimethylbutane, 68.0 kPa (9.86 psi); 2,3-dimethylbutane, 51.1 kPa (7.41 psi); 2-methylpentane, 46.7 kPa (6.77 psi);cyclohexane, 22.5 kPa (3.26 psi);and toluene, 7.1 kPa (I.03 psi).v NOTE 4 ~ I t iS recommended that at least one type of control sample used in I0.I be representative of the samples regularly tested by the laboratory. The total vapor pressure measurement process (including operator technique) can be checked periodically by performing this test

method on previouslyprepared samples from one batch of product, in accordance with the procedure described in 8.1.2. Samples should be stored in an environment suitable for long term storage without sample degradation. Analysisof resultsfrom these quality controlsamplescan be carriedout using control chart techniquess or other statistically equivalent techniques.

9. Preparation of Apparatus 9.1 Prepare the instrument for operation in accordance with the manufacturer's instructions. 9.2 Prepare the sample introduction accessories, if required, according to the manufacturer's instructions. 9.3 Chill the sample syringe to between 0 and 4.5°C (32 and 40*F) in a refrigerator or ice bath. Avoid water contamination of the syringe reservoir by suitably sealing the outlet of the syringe during the cooling process. 9.4 Clean and dry the test chamber according to the manufacturer's instructions. With the test chamber sealed observe that the instrument display is stable and does not exceed 0.00 + 0.20 Ida (0.00 + 0.03 psi). 9.5 If in doubt of the cleanliness of the cell, refer to the cleaning procedure in the manufacturer's instructions, or if the display does not return to zero, refer to the calibration procedure in the manufacturer's instructions. 9.6 Verify that the temperature of the test chamber is within the required range from 37.8 + 0.1°C (100 + 0.2"F). 10. Calibration 10.1 Pressure Transducer: 10.1.1 Cheek the calibration of the transducer according to the manufacturer's instructions on a monthly basis or when needed as indicated from the quality control checks (Section 1 I). The calibration of the transducer shall be checked using two reference points, ambient barometric pressure, and a pressure above ambient pressure, determined by the operator, which is at least 80 % of the expected maximum pressure encountered during the test. I0.1.2 The above ambient pressure shall be measured by a mercury manometer with a scale resolution of at least 0.20 Ida (0.03 psi). 10.2 TemperatureMeasuring Device---Checkthe calibration of the temperature measuring device used to monitor the temperature of the test chamber at least every six months against a thermometer traceable to a national standard.

12. Procedure 12.1 Remove the sample from the cooling bath or refrigerator, dry the exterior of the container with absorbent material, uncap, and insert a chilled syringe. Draw a bubblefree aliquot of sample into the gas tight syringe and deliver this test specimen to the test chamber as rapidly as possible. The total time between opening the chilled sample container and securing the syringe into the test chamber shall not exceed 1 min. 12.2 Follow the manufacturer's instructions for injection of the test specimen into the test chamber, and for operation of the instrument to obtain a vapor pressure result for the test specimen. 12.3 If the instrument is capable of calculating the dry vapor pressure equivalent automatically, ensure that the equation in 13.2 is used. 13. Calculation 13.1 Record the vapor pressure reading from the instrument to the nearest 0.1 kPa (0.01 psi). For instruments that do not automatically record a stable pressure value, manually record the pressure indicator reading every minute to the nearest 0.1 kPa. When three successive readings agree to within 0.1 kPa, record the result to the nearest 0.1 Ida (0.01

psi).

13.2 Calculate the dry vapor pressure equivalent (DVPE) using Eq. 1. Ensure that the instrument reading used in this equation corresponds to the total pressure and has not been corrected by an automatically programmed correction factor. Use the variable pertaining to the type of equipment utilized.

DVPE, kPa (psi) = (0.965 X) + A

(1)

where: X ffi measured total vapor pressure in Ida (psi), A ffi 0.538 Ida (0.078 psi) for HERZOG Model SC 970, and A ffi 1.937 I d a (0.281 psi) for ABB Model 4100. NOTe 5--The correlation equationswerederived from data obtained in a 1991 interlaboratory cooperative test program? The equations

11. Quality Control Checks 11.1 Check the performance of the instrument each day it is in use by running a quality control sample consisting of a pure solvent of known vapor pressure similar to the vapor pressure of the samples to be tested. Treat the quality control check sample in the same manner as a sample. If the observed vapor pressure differs from the reference value by more than 1.0 I d a (0.15 psi), then check the instrument calibration (Section 9). 11.2 Some possible materials and their corresponding

e "Ph~ical Constants of H y d r o g e n and Non-Hydrocarbon Materials," availablefrom ASTM Headquarters. Order PCN 28-003092-12. 7 "Manual on Presentation of Data and Control Chart Analyd&"ASTM MNL 7, Sixth Edition, 1990, Section 3. e The vapor pressure values cited were obtained from Ph//lJps Pctroleum Company, Bartlesville, Oklahoma or the Table of Phys/cal Constan~ Gas Processors Association--Stsndard 2145.

910

~

D 5482

correct for the relative bias between the measured vapor pressure and the dry vapor pressure obtained in accordance with Test Method D 4953, Procedure A.

material would, in the long run, exceed the following value only in one case in twenty: 2.69 kPa (0.39 psi) for HERZOG Model SC 970 4.14 kPa (0.60 psi) for ABB Model 4100

13.3 The calculation described in Eq. l can be accomplished automatically by the instrument, if so equipped, and in such cases the user shall not apply any further correction.

15.2 Bias--Since there is no accepted reference material suitable for determining the bias for the procedures, bias cannot be determined. 15.3 Relative Bias--Statistically significant relative biases were observed in the 1991 intedaboratory cooperative test program s between the total pressure obtained using instruments described in this test method and the dry vapor pressure obtained using Test Method D 4953, Procedure A. These biases are corrected by applying Eq. 1. NOTE 7--The bias and precision information provided for the ABB apparatus are applicable only for the instruments manual mode of operation, for a nominal vapor pressure range of 13.8 to 82.68 Ida (2 to 12 psi). 15.4 Reproducibility Between Methods: NOTE 8uJust as the reproducibility supplies a 95 % confidence level on the difference between measurements by two different laboratories using the same method, there exists an equivalent reproducibility describing the 95 % confidence level on the difference between measurements by two laboratories using different methods. 15.4.1 A statistically based method for calculation of reproducibility between different methods was developed as listed below:

14. Report 14.1 Report the following information: 14.1.1 Report the dry vapor pressure equivalent to the nearest 0.1 kPa (0.01 psi) without reference to temperature.

15. Precision and Bias 15.1 The precision of this procedure as determined by the statistical examination of interlaboratory test results is as follows: NOTE 6--The following precision data were developed in a 1991

interlaboratory cooperative test program.9 Participants analyzed sample sets comprised of blind duplicates of 14 types of hydrocarbons and hydrocarbon-oxygenate blends. The oxygenates used were ethanol and MTBE. The oxygenate content ranged nominally from 0 to 15 % by volume and the vapor pressure ranged nominally from 14 to 100 Ida (2 to 15 psi). A total of 60 laboratories participated. Some participants performed more than one test method, using separate sample sets for each. Thirteen sample sets were tested by this test method using two different instruments, 26 sample sets were tested by Test Method D 4953, 13 by Test Method D 5190 and 27 by Test Method D 5191. In addition, six sets were tested by modified Test Method D 5190.

15.1.1 Repeatability--The difference between successive test results obtained by the same operator with the same apparatus under constant operating conditions on identical test material would, in the long run, in the normal and correct operation of the test method exceed the following value only in one case in twenty: 1.31 kPa (0.19 psi) for HERZOG Model SC 970 1.79 kPa (0.26 psi) for ABB Model 4100

where: Rz, R2 = the reproducibility figures for each method under consideration, methods one and two, respectively, and n,, n2 = the number of labs whose data was used to calculate RI and R2, methods one and two, respectively. For this test method the number of labs is six.

15.1.2 Reproducibility.--The difference between two single and independent test results obtained by different operators working in different laboratories on identical test

16. Keywords

9The results of this test program are filed at ASTM H~quarters. Request

RR:D02-1286.

16.1 dry vapor pressure equivalent; gasoline; hydrocarbon-oxygenate blends; Mini Method-Atmospheric; petroleum products; vapor pressure

The American Society for Testing and Materials takes no position respecting the vaildlty of any patent rights ~ a r t e d In connection with any item mentioned In this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, end the risk of infringement of such rights, are entirely their own responsibility. This atandard is subject to revision at any time by the responsible technical ¢~rnmlttee and must be reviewed every five years and If not revised, either rsepproved or withdrawn. Yourcomments are Invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responalble technical committee, which you may attend, ff you feel that your comments have not reoaived e fair hearing you should make your views known to the ASTM Committee on Standards, 100 Barr Harbor Dr/ve,WestConshohockan, PA 19428.

911

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Designation: D 5 5 0 3 - 9 4

Standard Practice for, Natural Gas Sample-Handling and Conditioning Systems for Pipeline Instrumentation 1 This standard is issuedunderthe fixeddesignationD 5503;the numberimmediatelyfollowingthe designationindicatesthe yearof originaladoptionor, in the caseof revision,the yearof last revision.A numberin parenthesesindicatesthe yearof last reapproval.A superscriptepsilon(~) indicatesan editorialchangesincethe last revisionor reapproval.

1. Scope l.l This practice covers sample-handling and conditioning systems for typical pipeline monitoring instrumentation (gas chromatographs, moisture analyzers, etc.). The selection of the sample-handling and conditioning system depends upon the operating conditions and stream composition. 1.2 This practice is intended for single phase mixtures that vary in composition. A representative sample cannot be obtained from a two phase stream. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility t f the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 1.4 The values stated in SI units are to be regarded as standard. The values stated in English units are for information only. . Referenced Documents

2.1 A S T M Standards: D 1142 Test Method for Water Vapor Content of Gaseous Fuels by Measurement of Dew-Point Temperature 2 D3764 Practice for Validation of Process Stream Analyzers 3 2.2 Other Documents: ANSI/API 2530 (AGA Report Number 3)4 AGA Report Number 85 NACE Standard MR-01-756 3. Terminology 3.1 Definitions: 3. I. 1 compressed natural gas--natural gas compressed to approximately 3600 psi. 3.1.2 density--mass per unit volume of the substance being considered. 3.1.3 dew point--the temperature and pressure at which the first droplet of liquid forms from a vapor. This practiceis underthe jurisdictionof ASTMCommitteeD-3 on Gaseous Fuelsand is the direct responsibilityof SubcommitteeD03.01 on Collectionand Measurementof GaseousSamples. CurrenteditionapprovedFeb. 15, 1994.PublishedApril 1994. 2AnnualBook ofASTM Standards, Vol 05.05. 3AnnualBookof ASTM Standards, Vol 05.02. 4AvailablefromAmericanNationalStandardsInstitute, 11 W. 42ndSt., 13th Floor,NewYork,NY 10036. ~Available from American Gas Association, 1515 Wilson Boulevard, Arlington,Virginia22209. 6Availablefrom National Associationof CorrosionEngineers, 1440-TSouth CreekDrive,Houston,Texas77084. 912

3.1.4 lag time--time required to transport the sample to the analyzer. 3.1.5 natural gas--mixture of low molecular weight hydrocarbons obtained from petroleum-bearing regions. 3.1.6 sample probe--device to extract a representative sample from the pipeline. 3. 1.7 system turnaround t i m e n t h e time required to transport the sample to the analyzer and to measure the desired components. 4. Significance and Use 4.1 A well-designed sample-handling and conditioning system is essential to the accuracy and reliability of pipeline instruments: Approximately 70 % of the problems encountered are associated with the sampling system. 5. Selection of Sample-Handling and Conditioning System 5.1 The sample-handling and conditioning system must extract a representative sample from a flowing pipeline, transport the sample to the analyzer, condition the sample to be compatible with the analyzer, switch sample streams and calibration gases, transport excess sample to recovery (or disposal), and resist corrosion by the sample. 5.2 The sample probe should be located in a flowing pipeline where the flow is fully developed (little turbulence) and where the composition is representative. In areas of high turbulence, the contaminates that normally flow along the bottom or the wall of the pipeline will form aerosols. 5.3 The purpose of the sample probe is to extract a representative sample by obtaining it near the center of the pipeline where changes in stream codaposition can be quickly detected. 5.3.1 The tip in the sample probe should be positioned in the center one third of the pipeline away from the pipeline wall where large particles accumulate. 5.3.2 The probe should be a minimum of five pipe diameters from any device that could produce aerosols or significant pressure drop. 5.3.3 The sample probe should not be located within a defined meter tube region (see ANSI/API 2530 AGA Report Number 3 and AGA Report Number 8 for more information). 5.3.4 The sample probe should be mounted vertically from the top on horizontal pipelines. The sample probe should not be located on vertical pipelines. 5.4 The sampling-handling system must transport the sample to the analyzer and dispose of excess sample. Since the sampling point and the analyzer may be separated by some distance, the time required to transport the sample to

~

D 5503

the analyzer can contribute significantly to the system turnaround time. 5.4.1 The analyzer should be located as close to the sampling point as is practical to minimize the sample lag time. 5.4.2 The sample-handling system should be equipped with a full open ball valve and a particular filter. 5.5 The sizing of the sample transport line will be influenced by a number of factors: 5.5. l The sample point pressure and the location of the pressure reduction regulator. 5.5.2 The acceptable lag time between the sample point and the analyzer. 5.5.3 The requirements of the analyzer such as flow rate, pressure, and temperature for the analysis. For multi-stream systems, the sample line and associated manifold tubing should be flushed with sufficient sample to assure a representative sample of the selected stream. 5.5.4 The presence of sample-conditioning elements will contribute to the lag time and must be considered in the calculation of the minimum sample flow rate. 5.5.4. l Each element could be considered as an equivalent length of sample line and added to the length of line from the sample point to the analyzer. 5.5.4.2 The purge time of each element is calculated as the time necessary for five volumes of sample to flow through the element. 5.5.5 A vapor sample must be kept at least 10*C above the hydrocarbon dew point temperature to prevent condensation of the sample. The sample line should be heat traced and insulated when appropriate. 5.5.5.1 For compressed natural gas (CNG) the pressure must be reduced in two stages to avoid condensation of liquids due to the Joule-Thompson effect. In a heated zone at approximately 50"C, the pressure should be dropped to approximately 10 MPa (1500 psig) and then to a suitable pressure for the analyzer. Any conditioning of the sample must be completed in the heated zone. 5.5.5.2 The sample line from the heated zone to the analyzer must be heat traced to avoid partial condensation of the sample.

METAL GASKET

OUT

IN

FILH

IN --'--~- ~ _

f,' ELEMENI

-

L-TAPERED BORE

~-- OUT

-

FILTER ELEMENT

FIG. 1 CrossSection of Common In-Line Filters

passes through a bypass filter while a majority of the sample passes across its surface, keeping it clean. The active filter element is either a disposable cartridge or a reusable sintered metal element. (See Fig. 2.) 6.1.2.3 Cyclone Filler--The cyclone filter is a centrifugal cleanup device. The sample enters at high velocity tangentially to the wall of a cylindrical-shaped vessel with a conical-shaped bottom. The centrifugal force developed by the spinning action of the gas as it follows the shape of the vessel forces particles and droplets to the wall where they are removed through the vent flow. (See Fig. 3.) 6.1.2.4 Coalescing Filter--Coalescers, also known as membrane separators, are used to force finely divided liquid droplets to combine into larger droplets so they can be separated by gravity. The design of the coalescer body forces the heavier phase out the bottom and the lighter phase out the top. The flow rates out the top and the bottom are critical for proper operation. (See Fig. 4.) (a) Since this process removes part of the sample, the impact on sample composition must be considered. (b) The coalescer should be located immediately upstream from the analyzer. 6.1.3 The combination condenser/separator is used to remove condensable liquids from a vapor sample. The sample enters the separator and cools as it passes through the

6. Apparatus 6.1 The following are common components of a samplehandling and conditioning system (see Refs (1) and ( 2 ) 7 for more information). 6.1.1 Ball valves, needle valves, and solenoid valves are typically used for stream switching, sample shutoff, calibration gas introduction, or sample vent and by-pass systems. 6.1.2 Most pipeline samples require some filtering. Since all filter elements eventually plug, they should be replaced on a regular maintenance schedule. There are several types of filter designs. 6.1.2. l In-line Filter--All of the sample passes through an in-line filter. The active filter elements are available in teflon polypropylene, co-polymer, or stainless steel. (See Fig. l.) 6. 1.2.2 Bypass Filter--Only a small portion of the sample

RLIERED Waif ~ IN~T

t

1

r~r n.ow CARI'RIOG([nLTgl S E~ A L S [U[MENT F~LTERED~

BOWL,ML'TAL.(;LASS ORPLASTIC

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r~ow

FILTERED S~PL£ OUT

7 The boldface numbers in parentheses refer to the list of references at the end of this practice.

ELEM~NT'NHE IR FILER ED

SImEREDFILTER ELEMENT

FIG. 2 Cioss Section of Common By-Pass Filters

913

(1~ D 5503 VAPOR SAMPLE OUTLET

CLEAN SAMPLE ~,AMPLE INLET

~

SECONDARYSPIRAL OF CLEAN GAS MOVES UP AND OUT OF TOP

SAMPLE ENTERS TANGENTIALLY

COOLING INLET

ROTATIONDEVELOPS

C

~]

COOLINGOUTLET

HIGH CENTRIFUGAL FORCE THROWING LIQUIDS TO OUTER WALL

LIQUIDS DISCHARGED IN VENT FLOW

FIG. 3

Cyclone Filter/Centrifugal Filter

II LIQUID OUTLET

LIQUID & VAPOR IN

FIG. 5

Combination Condensor/Separator

sample. A typical rotameter consists of a ball or float mounted in a tapered tube. The reading is proportional to fluid density and viscosity which may vary with the composition of the fluid. 6.1.6.1 The rotameter should be located downstream of the analyzer and used as an indicator of flow and system cleanliness. A clean tube and a freely moving ball is an indicator of a clean system. 6.1.7 Typical natural gas sample system. (See Fig. 6.) 6.1.8 Compressed natural gas sample system. (See Fig. 7.)

VAPOR OUT COALESCING-~ MEMBRANE

LIQUIDS OUT ~LYZ

FIG. 4

q

Coalescing Filter

VAPOR BYPASS

J device. The condensed liquid phase is separated by gravity and removed from the bottom of the separator. (See Fig. 5.) 6.1.3.1 Since this process removes part of the sample, the impact on sample composition must be considered. 6.1.3.2 The condenser/separator should be located immediately upstream from the analyzer. 6.1.4 Pressure regulators are required to reduce and regulate pressure between the sampling point and the analyzer. The regulator must be constructed of the proper materials to allow for the corrosive nature of the sample. 6.1.4.1 A combination sample probe and regulator with thermal fins around the probe could be used to minimize the Joule-Thompson effect. 6.1.5 Pressure gages should be installed downstream of the pressure regulator. Since the sensing element of these devices (Bourdon tube) consists of unswept volume, the pressure gage should be installed either in a bypass line or after the analyzer. 6.1.6 Rotameters are used to indicate the flow rate of the

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UOUtOORAtN ~ STANDARDIN

FLOWCONTROL

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DOUBLEBLOCK& BLEED STREAMSWITCHING

STREAMSWITCH VALV~VENT

HEATEDENCLOSURE USEDAS REQ'D

FIG. 6 Typical Natural Gas Sampling System

914

~) D 5503 ATM PRESSURE

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~

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- ~ - TO.MPLE CONDHIONING

STREAM 2 IN

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REDUCTION

-

~20

SAMPLE PRESSURE PSIG

SYSTEM

400

....

,/.'ToBE

TOSAMPLE CONDIIIONING SYSTEM

~

]

DeC/M,.

100 N LAG TIME = L x V = 75 WIN fs

HEATED ENCLOSURE

FIG. 7

HIGH PREJ':,URE GAS SAMPLE TRANSPORT LINE

Pressure Reduction System for Compressed Natural Gas (CNG) SAMPLEPRESSURE 400PSIG

7. Materials 7.1 Many of the common sample system components are constructed of metals such as 316 stainless steel, Hastelloy, and Monel and compatible plastics such as Kel-F, Teflon, and Kynar. 7.1.1 The sample-handling and conditioning system should be constructed of material capable of resisting corrosion from the sample and the environment. 7.l.l.1 Sample system components should be chosen carefully to avoid corrosion or adsorption by the sample. 7.1.1.2 If sour gas (gas that contains hydrogen sulfide or carbon dioxide, or both) is suspected, NACE Standard MR-01-75 should be followed. 7.2 The sample-handling and conditioning system should contain the sample under the most severe conditions of pressure, temperature, and vibration that the pipeline will experience during normal and upset conditions.

VL(P + Prom) F,,P,,,

F-~ ,%T;E L ~

~

DOCC/MIN

--

LAG TIME = L F s V

= 7-I/2

MIN

O~

HIGH PRESSURE GAS SAMPLE TRANSPORT UNE WITH FAST LOOP

~MPLE PRESSURE

400PSIG

2000CC/MIN I~

00 CC/MIN

TUBE [

1/4" 100 E'r

LAG TIME = L Fs V = I MIN

HIGHPRESSURECA',SAMPLETRANSPORTLINEWITHFASTLOOP

AND PRE%%URE REDUCTION AT SAMPLE POINT (TEMPERATURE CORRECTIONS )lAVE BEEN )GNORED IN THE CALCUALTION OF LAG TIME)

FIG. 8

Example Calculations of Lag Time

L = La + Leq (2) where: L = equivalent length of sample line, m, Ld = length of sample line, m, and Leq = equivalent length of valves and fittings, m. 8.3 Calculation of sample line size is a trial and error process: 8.3.1 Select a sample line size that meets the flow rate needs of the analyzer. 8.3.2 Calculate the Reynold's number, the ratio of iner= tial=to=viscous forces by:

8. Calculation 8.1 Sample transport time, or lag time, hag, is a function of the sample line length and diameter, the absolute pressure in the line, and the sample flow rate. Lag time is calculated as follows: l/ae =

~ 2000CC/MIN

( 1)

where: hag = sample transport time, rain, V = volume of sample per unit length, cm3/m, L = equivalent length of sample length, m, P = sample pressure, N/m 2, P,,,, = atmospheric pressure, N/m 2, and Fa = actual average flow rate of the sample, cm3/min. 8.1.1 E x a m p l e - - C o n s i d e r a sample point located 100 ft away from an analyzer requiring 200 cm3/min of sample. Using standard conditions and 0.19 in. inside diameter tubing, a lag time of 75 min can be calculated. By increasing the sample flow to 2200 cm3/min and splitting the excess sample to a high-speed loop, the lag time decreases to 7.5 min. The sample pressure should be reduced at the analyzer. 8.1.2 Reducing the pressure at the sample point rather than the analyzer can also decrease the lag time. For a pressure reduction from 400 psig to 40 psig, the sample flow should be 2000 cm3/min to compensate for the increase in sample volume. (See Fig. 8.) 8.2 The equivalent length of sample line is calculated by the following expression (see Ref (3) for more information):

Re = a~,___a ))

(3)

where: R e = Reynold's number, p = fluid density, Kg/m 3, ~t = fluid velocity, m/s, d = diameter of the pipe, m, and )7 = viscosity of the fluid, Ns/m 2. 8.3.3 Calculate the pressure drop using Darcy's equation (see (3) for more information): dp = fpLu2

2dg where: dp -- pressure drop in the line, N/m 2, f = frictional factor from Moody's tables, a = fluid density, Kg/m 3, L = equivalent length of sample line, m, 915

(4)

4@) D 5503 be calculated without the aid of a computer by the following procedure: 8.4.1.1 Assume a dew point temperature. Using a DePriester chart, determine the K at the highest pressure present in the sample line and the assumed dew point for each component in the sample (see Ref (6) for more information). 8.4.1.2 Calculate the mole fraction, y, for each component in the vapor phase. 8.4.1.3 Calculate the mole fraction, x, for each component in the liquid phase. At the dew point, the summation of the xi's should be between 0.95 and 1.0. 8.4.2 The dew point calculation depends upon the accuracy of the stream composition. Small errors in the composition (especially in the heavier hydrocarbons) will cause large errors in the hydrocarbon dew point. 8.4.3 The dew point could be determined using a Bureau of Mines Type chilled mirror hygrometer (see Test Method D 1142 for more information).

u = velocity of the fluid, m/s, d = diameter of the line, m, and g = acceleration of gravity, 9.81 m/s 2. 8.3.4 The available pressure drop should be compared with the calculated pressure drop. If the calculated pressure drop is too great, then select a larger sample line and repeat lag time, equivalent length, and pressure drop calculations. 8.3.5 The majority of sample transport problems are solved by application of prior experience and by use of tables relating velocity to pressure drop for different sample line diameters (see Refs (4) and (5) for more information). 8.4 The dew point calculation relies on the use of distribution coefficients, Ki, which are defined as the ratio of the mole fraction of the component in the vapor phase, Y,, to the mole fraction in the liquid phase, xi. K, =

xj

(5)

8.4.1 Whenever possible, dew point should he calculated using a physical properties software package. Dew point can

9. Keywords

9.1 natural gas; pipeline instrumentation

REFERENCES (4) Moody, L. F., "Friction Factors for Pipe Flow," Trans. Am. Soc. Mech. Engnrs., 66:671-678 (I 944) (5) Clevett, K. J., Process Analyzer Technology, NY: John Wiley and Sons (1986) (6) DePriester, K., Chem. Eng. Progr. Syrup. Ser. 7, 49: ! (1953)

(1) Cornish, D. C., Jepson, G., and Smarthwaite, M. J., Sampling Systems for Process Analyzers, London: Butterworth (1981) (2) Annino, R. and Villalobos, R., Process Gas Chromatography, ISA Research Triangle Park, NC: (1992) (3) "Flow of Fluids through Valves, Fittings and Pipe," Technical Paper No. 410, Chicago, Ill: Crane Co., (1978)

The American Society for Testing and Materials takes no position respecting the vatld/ty of any patent rights asserted in connection with any Item mentioned in this standard. Users of this standard are expressly advised that datarminat/on of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision st any time by the responsible technical committee and must be reviewed every five years and if not revised, s/thar reapproved or withdrawn. Your comments are Invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful cons/daratlon at a meeting of the responsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103.

916

(~)

Designation: D 5504 - 94 Standard Test Method for Determination of Sulfur Compounds in Natural Gas and Gaseous Fuels by Gas Chromatography and Chemiluminescence I This standard is issued under the fixed designation D 5504; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last re.approval. A superscript epsilon (0 indicates an editorial change since the last revision or re.approval.

3.1.1 A common abbreviation of hydrocarbon compounds is to designate the number of carbon atoms in the compound. A prefix is used to indicate the carbon chain form, while a subscript suffix denotes the number of carbon atoms (for example, normal decane = n-C~o; Iso-tetradecane ffi I-CI4). 3.1.2 Sulfur compounds are commonly referred to by their initials (chemical or formula), for example, dimethyl sulfide = DMS; carbonyl sulfide = COS.

1. Scope 1.1 This test method provides for the determination of individual volatile sulfur-containing compounds in gaseous fuels including natural gas. The detection range for sulfur compounds, reported as picograms sulfur, is ten (10) to one million (1,000,000), This is equivalent to 0.01 to 1,000 mg/m 3, based upon the analysis of a 1 cc sample. 1.2 The test method does not purport to identify all individual sulfur species. The detector response to sulfur is equimolar for all sulfur compounds within the scope (1. I) of this test method; thus unknown individual compounds are determined with equal precision to that of known compounds. Total sulfur content of samples can be estimated from the total of the individual compounds determined. 1.3 The values stated in SI units are to be regarded as standard. The values stated in inch-pound units are for information only. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

4. Summary of Test Method 4.1 The analysis of gaseous sulfur compounds is difficult because of the reactive nature of these materials. They pose problems both in sampling and analysis. Analysis is ideally performed on-site to eliminate potential sample deterioration. Sampling must be done using containers proven to be nonreactive, such as Tedlar bags. Laboratory equipment must also be inert and well conditioned to ensure reliable results. Frequent calibration using stable standards is required in sulfur analysis. 4.2 A one cc sample of the fuel gas to be analyzed is injected into a gas chromatograph where it is passed through a 60 meter, megabore, thick film, methyl silicone liquid phase, open tubular partitioning column, and separated into its individual constituents. 4.3 Sulfur Chemiluminescence Detection--As sulfur compounds elute from the gas chromatographic column they are combusted in a flame ionization detector (liD). These combustion products are collected and transferred to a .sulfur chemiluminescence detector (SCD). This detection technique provides a highly sensitive, selective, and linear response to volatile sulfur compounds and may be used simultaneously while the usual fixed gas and hydrocarbon determinations are being made. 4.4 Other Detectors--This test method is written primarily for the sulfur chemiluminescent detector but other sulfur specific detectors can be used provided they have sufficient sensitivity, response to all sulfur compounds of interest, and do not suffer significant hydrocarbon interference. 4.4.1 Lead Acetate Rate of Stain Detector--This detector relies on all sulfur compounds from the column passing through a high temperature hydrogenator. All sulfur compounds are transformed to hydrogen sulfide and sent to a hydrogen sulfide detector. The detector uses optical measurement of the rate of darkening of a lead acetate tape to detect the eluting sulfur compound. 4.4.2 Electrochemical Detectors--Electrochemical detectors specific to sulfur may be used.

2. Referenced Documents

2.1 A S T M Standards: D 1072 Test Method for Total Sulfur in Fuel Gasese D 1145 Method of Sampling Natural Gas 2 D 1945 Test Method for Analysis of Natural Gas by Gas Chromatography 2 D 2725 Test Method for Hydrogen Sulfide in Natural Gas (Methylene Blue Method) 2 D 3031 Test Method for Total Sulfur in Natural Gas by Hydrogeneration 2 D 4468 Test Method for Total Sulfur in Gaseous Fuels by Hydrogenolysis and Rateometric Colorimetry2 D 4626 Practice for Calculation of Gas Chromatographic Response Factors 3 E 594 Practice for Testing Flame Ionization Detectors Used in Gas Chromatography 4 3. Terminology 3.1 Abbreviations: I This test method is under the jurisdiction of ASTM Committee D-3 on Gaseous Fuels and is the direct responsibility of Subcommittee D03.05 on Determination of Special Constituents of Gaseous Fuels. Current edition approved Feb. 15, 1994. Published April 1994. 2 Annual Book of ASTM Standards, Vol 05.05. 3 Annual Book of ASTM Standards, Vol 05.02. ";Annual Book of ASTM Standards, Voi 14.01.

917

@

o

sso4

NOTE l---Carbonylsulfide is not detected by some of these detectors because of its stability. 4.3 Flame Photometric Detectors~Flame photometric detectors can be used if sensitivity and hydrocarbon interference are not a problem.

6.1.4.1 F/D--The detector must meet or exceed the typical specifications given in Table 1 of Practice E 594 while operating in the normal mode as specified by the manufacturer. The detector must be capable of operating continuously at a temperature equivalent to the maximum column temperature employed. Connection of the column to the detector must be such that no temperature below the column temperature exists. The detector design must be such to allow the insertion of the SCD sampling probe into the flame without interrupting the detection of the hydrocarbon response. 6.1.4.2 SCD--The sulfur chemiluminescence detector shall meet or exceed the following specifications: (1) greater than l0 s linearity, (2) less than 5 pg S/s sensitivity, (3) greater than 106 selectivity for sulfur compounds over hydrocar. bons, (4) no quenching of sulfur compound response, and (5) no interference from co-eluting compounds at the usual GC sampling volumes. 6.1.4.3 As sulfur compounds elute from the gas chromatographic column they are combusted in a hydrogen-rich flame of a flame ionization detector (liD) producing numerous combustion products, one of which is sulfur monoxide (Reaction 1). These combustion products are collected and removed from the flame using a ceramic sampling tube (probe) interface and transferred under a vacuum through a flexible tube to the reaction chamber of the sulfur chemiluminescence detector (SCD). Sulfur monoxide is then sensitively detected by an ozone/sulfur monoxide chemiluminescent reaction to form electronically excited sulfur dioxide, which relaxes with emission of light in the blue and the ultraviolet regions of the spectrum (Reaction 2). Figure O presents a simple schematic of the detector configuration. Sulfur compound + hydrogen/air flame ~ SO + products (1) SO + O~ --, SO2 + O2 + Hv (2) where Hv ffi chemiluminescent light energy. 6.2 Column--A 60 m x 0.54 mm ID fused silica open tubular column containing a 5 I~m film thickness of bonded methyl silicone liquid phase is used. The column shall provide retention and resolution characteristics as listed in Table 2 and illustrated in Figure 1. The column will also demonstrate a sufficiently low liquid phase bleed at high temperature such that no loss of the SCD sulfur response is encountered while operating the column at 200"C. 6.3 Data Acquisition: 6.3.1 RecordermA 0 to 1 mV range recording potentiometer or equivalent, with a full-scale response time of 2 s or less can be used. 6.3.2 lntegratormThe use of an electronic integrating

5. Significance and Use 5.1 Many sources of natural gas and petroleum gases contain varying amounts and types of sulfur compounds which are odorous, corrosive to equipment, and can inhibit or destroy catalysts employed in gas processing. 5.2 Small amounts (for example, 1-2 ppm) of sulfur odorant compounds are added to natural gas and LP gases for safety purposes. Some odorant compounds are not absolutely stable and tend to react to form more stable compounds having lower odor thresholds. Sulfur odorant levels are therefore analyzed to help ensure proper safety with fuel gases. 5.3 Current Analytical Methods~Gas chromatography (GC) is commonly used to determine the fixed gas and organic component composition of natural gas (Test Method D 1945). Other standard methods for the analysis of sulfur in fuel gases include Test Methods D 1072, D3031, and D 4468 for total sulfur and Test Method D 2725 for hydrogen sulfide. 6. Apparatus 6.1 Chromatograph--Any gas chromatograph that has the following performance characteristics can be used: 6.1.1 Column Temperature Programmer--The chromatograph must be capable of linear programmed temperature operation over a range of 30 to 200"C, in programmed rate settings of 0.1 to 30"C/min. The programming rate must be sufficiently reproducible to obtain retention time repeatability of 0.05 min (3 s) throughout the scope of this analysis. 6.1.2 Sample Inlet SystemmThe sample inlet system must be capable of operating continuously at a temperature up to the maximum column temperature employed. A splitting injector is recommended, capable of splitless or accurate split control in the range of 10:1 to 50:1. An automated gas sampling valve is also recommended. The inlet system must be well conditioned and evaluated frequently for compatibility with trace quantities of reactive sulfur compounds. 6.1.3 Carrier and Detector Gas Control--Constant flow control of carrier and detector gases is critical to optimum and consistent analytical performance. Control is best provided by the use of pressure regulators and fixed flow restrictors. The gas flow rate is measured by any appropriate means and the required gas flow indicated by the use of a pressure gage. Mass flow controllers, capable of maintaining gas flow constant to ± 1% at the required flow rates can also be used. The supply pressure of the gas delivered to the gas chromatograph must be at least 69 kPa (10 psig) greater than the regulated gas at the instrument to compensate for the system back pressure. In general, a supply pressure of 552 kPa (80 psig) will be satisfactory. 6.1.4 Detector--Both a flame ionization detector (liD) and a sulfur chemiluminescence detector (SCD) are used. Other detectors as in 4.4 will not be covered in detail in this test method.

TABLE 1

Typical Gas Chromatographic OperaUng Parameters

Injector. gas sample loop: 150°C Injector. splitless: Flame ionization detector: 2500C

1.0 cc 150=C 100 ',r. sample to column H2: 200 cma/min Air: 400 cma/min Make-up gas (He): 20 crna/min SCD: output at 0--1 V cell pressure at 8.7 torr Column Oven: 1.5 min at 30°C 15.0=/min to 200*C hold at 200°C as required Carrier gas (helium): adjust to methane retention time of 1.10 min 14.5 kPa (20 psig) or approximately 11 cma/min

918

q~) D 5504 TABLE 2

6.3.2.5 External standard calculation and data presentation.

Retention T l m e - - 4 u SPB1

Conditions as in Table 1 Compound Methane Ethylene Ethane Hydrogen Sulfide Propylene Carbon}4 Sulfide Propane Sulfur Dioxide I-Butane Butene-1 n-Butane Methanethiol t-Butene-2 2,2-DMO3 ¢-IButene-2 3-Me-Butene-1 I-Pentane Pentene-1 Ethanethiol ~ e - 1 n-Pentane Isoprene t-Pentene-2 Dimethylsulfide o-Pentene-2 2-Me-Butene-2 Carbon Disulfide 2,2.DMO4 i-Propanethiol Cyclopentene 3-MePentadiene CP/2,3-DMO4 2-MO5 t-Butanethiol 3-MO5 Hexene-1 n4~oanethiol n-Hexane MethylEthylSulfide MeCyC5 Benzene s-Butanethiol

Ave. RT mln 1.458 1.733 1.730 2.053 2.550 2.586 2.679 2.815 4.422 5.263 5.578 5.804 5.938 6.009 6.409 7.463 8.035 8.500 8.583 8.717 8.860 8,963 9.096 9.117 9.321 9.463 9.617 9.898 10.222 10.392 10.525 10.733 10.883 11.278 11.269 11.392 11.625 11.720 11.779 12.457 13.154 13.154

Compound ?S n-Octane ?S S ?S ?-EtThiophene ?S ?S ?S ?S m&p-Xylene ?S ?S ?S o-Xylene ?S n-None ?S ?S DIEthylDiSulfide ?S ?S ?S ?S ?S 2,2,4-TriMeBz n.Decane ?S ?S ?S ?S n-Undecane ?S ?S ?S n-Dodecane Beflzothlophene n-Tridecane MeBzThiophene MoBzThiophene MeBzThiophene MeBzThiophene

Ave. R'l" mln 16.363 16.423 16.425 16.592 16.692 16.983 17.183 17.319 17.631 17.754 17.788 17.913 18.053 18.139 18.279 18.450 18.448 18.567 18.642 18.767 18.911 19.008 19.125 19.292 19.979 20.227 20.308 20.550 21.396 21.733 21.808 22.033 22.208 22.417 23.046 23.631 23.717 25.134 25.225 25.328 25.433 25,550

7. Reagents and Materials 7.1 Sulfur Compound Standards--Gaseous permeation tube standards shall be used for all sulfur compounds to be determined. 7.2 Permeation tubes will be weighed to the nearest 0.1 mg on a monthly basis and standard concentration calculated by weight loss and dilution gas flow rate. 7.3 Compressed Cylinder Gas Standards--As an alterna. five, blended gaseous sulfur standards may be used if a means to ensure accuracy and stability of the mixture is available. These mixtures can be a source of error because of instability. NOTE 4: Warning--Sulfur compounds may be flammable and harmful or fatal if ingested or inhaled.

7.4 Carrier Gas--Helium or nitrogen of high purity (Warning--See Note 5). Additional purification is recommended by the use of molecular sieves or other suitable agents to remove water, oxygen, and hydrocarbons. Available pressure must be sufficient to ensure a constant carrier gas flow rate (see 6.1.3). NOTE 5:,Warning--Helium and nitrogen can be compressed gases under high pressure.

7.5 Hydrogen--Hydrogen of high purity (for example, hydrocarbon free) is used as fuel for the flame ionization detector (FID) (Warning--See Note 6). NOTE 6: Warning--Hydrogen is an extremely flammable gas under high pressure.

7.6 Air--High purity (for example, hydrocarbon free) compressed air is used as the oxidant for the flame ionization detector (liD) (Warning--See Note 7). NOTE 7: Warning--Compressed air can be a gas under high pressure and supports combustion.

device or computer is recommended. A dual channel system is useful for simultaneous presentation of both the l i d and SCD signals. The device and software must have the following capabilities: 6.3.2.1 Graphic presentation of the chromatogram. 6.3.2.2 Digital display of chromatographic peak areas. 6.3.2.3 Identification of peaks by retention time or relative retention time, or both. 6.3.2.4 Calculation and use of response factors.

8. Preparation of Apparatus and Calibration 8.1 Chromatograph--Placein service in accordance with the manufacturer's instructions. Typical operating conditions are shown in Table 1. Hydrogen and air flows are critical for the FID reducing flame to give the SCD optimum sensitivity. 8.2 SCD--Place in service in accordance with the manufacturer's instructions. With the l i d flame ignited, put the probe assembly in place. The probe placement location is critical to maximum sensitivity. Ensure proper location before continuing. After sufficient equilibration time (for example, 5-10 rain), adjust the detector output signal or integrator input signal to approximately zero. Monitor the signal for several minutes to verify compliance with the specified signal noise and drift. 8.2.1 Sample Injection--Inject 1.0 cc from a sample loop of the calibration standard gas mix that covers the concentrations of interest. 8.2.2 Detector Response Calibration--Analyze the calibration gas and obtain the chromatograms. Calculate the relative response factor for each sulfur compound:

pJ

|.,., .

:

;~L

r,a~

~

Ix/

N. ~

II

la,

H .

.

.

,

.

.

.

.

2

.

4 T i m e

FIG. 1

.

.

, 6

.

.

.

,

,

1

_

8

( m l n . )

Standard Perm Tube Analysis Run

r,, = (c./A,,)

919

(3)

~1~ D 5504 TABLE

2000~ 19OO:

Compound

3 SulfurGas Standard

Mol. Wt. Density BP°C

"/oS

E

1,008". 1700~

B~"

~..

1500"

w ~ U

16

P¢ =

t4eei 1300;

j

, =,

=

,

FIG. 2

4

I

Time

'l .

-~

d

l-

i

.

Hydrogen Sulfide (H=S) Carbonyl Sulfide (COS) Methanethlol (MESH) Ethanethiol (EtSH) Dlmethylsulflde (DMS) Carbon Disulfide (CS=) 2.Propanethiol (IPrSH) t-Butanethiol (tBSH) 1-Propane~lol (nPrSH) IVlethylethylsulflde(MES) Thlophene (TP) s-Butanethi~ (s-BuSH) kButanethlol (I-BuSH) Olethylsulflde (DES) n-Butenethiol (n-BuSH) Dlmethyk:llsulflde(DMDS) DlethyMleulflde (DEDS)

i

(mln.)

Natural c o l A n a l y l i l - S u l f u r Compounds

P.OE43

S.0£4~

34.08

1.1857 1.24 48.110 0.8665 62.134 0.8391 62.134 0.9483 76.14 -76.160 0.8143 64.220 0.8002 76.160 0.3415 76.160 0.8422 54.14 1.07 90.186 0.8299 90.166 0.8343 90.190 0.8362 90,186 0.9416 94.200 1.6825 122.252 0.9931

60.35

--6.2 35.0 37.3

~ 52.6 65.0 67.0 67.0 84.16 65.0 68.7 92~) 98.5 109.7 154.0

94.06 53.37

68.65 51.61 51.61 54.23 42.10 49.93 42.10 42.10

35.03 35.66 35.56 35.55 35.56 68.35 52.46

(Conversion) Mg/M3per PPMV 1.35 2.46 1.97 2.54 2.54 3.11 3.11 2.62 3.11 3.11 3.44 3.69 3.69 3.69 3,69 3.85 5.00

5.0(4~

TABLE 4

4.9(4~ 3.0[4~

g=

2.O(4~

u

J:

~ J:

-cs'S-_cT,s__ca,s_

100001, .o^ 8

FIG. 3

i

.A

I 4"

i -

. "

Time

|

I g

(min.)

"

i

"

"

" |~

Calibration Table

SIEVERS 6 PTUBES NEW DETuMEGABORE/2OPSIG He 516/91 SPLITLJESS Calibration file: DATA:SVPT.Q Last Update: 24 Jul 91 5:37 pm Reference Peak Window: 5.00 "/, of Retention Time Non-Reference Peak Window: 5.00 ~ of Retention Time Sample Amount: 0.000 Uncallbrated Peak RF: 60.00e-6 Multiplier: 1.000 " |i

Natural Gas Analysis-Hydrocarbon Compounds

where: F, ffi response factor of compound. C, ffi concentration of the sulfur compound in the mixture. A, = peak area of the sulfur compound in the mixture. The response factor (F,) of each single sulfur compound should be within 10 % of F, for dimethyl sulfide. Figure 1 provides an example of a typical chromatogram and Table 4 shows the data and calibration report. Table 3 contains information useful for calibration calculations.

Rot Time

Ph#

Signal Descr

Amt PPMV

1.461 1.595 2.861 3.529 3.809 4.185 4.481 5.179 5.521 6.738 7.129 7.868 7.912 9.017

I 2 3 4 5 6 7 8 9 10 11 12 13 14

GC Signal I GC Signal 1 GC Signal 1 GC Signal 1 GC Signal 1 GC Signal 1 GC Signal 1 GC Signal 1 GC Signal 1 GC Signal 1 GC Signal 1 GC Signal 1 GC Signal 1 GC Signal I

0.9100 0.2610 0.3570 0.4150 0.4943 0.2269 0.3904 0.6140 2.600 0.9670 1.226 1.135 0.07660 1.558

cvl RespFact

Pk-Type Partial Name 1 59.60e-.6 I H2S 1 35.~o-6 1 COS 1 50.11e-6 1 MTM 1 50.28e-6 1 ETM 1 49.02e-6 1 DMS 1 0001001 1 CS2 1 50.04e-6 1 1PM 1.49.99e-6 1 TBM 1 50.00e-6 1 MES 1 49.29e-6 1 SBM 1 48.81e-6 1 DES 1 49.99e-6 1 NBM 1 0.0001000 1 DMDS 1 49.99e-6 1 THT

puter-based chromatographic data system. Examine the graphic display or digital data for any errors (for example, over-range component data).

9. Procedure

9. l Sampling and Preparation of Sample Aliquots: 9.l.l Gas Samples--Samples will be supplied to the laboratory in specially conditioned high-pressure sample containers or in Tedlar bags at atmospheric pressure. Such bags for H2S analysis must be run within 24 h of sampling. 9.2 Table 1 lists the gas chromatograph operating parameters. Table 2 provides a partial listing of the retention times of light sulfur compounds. Figures 1 and 2 illustrate typical analyses of a standard mixture and natural gas. 9.3 External Standard Calibration--At least once a day or as frequently as deemed expedient, analyze the calibration standard mix and determine standard response factors (see 10.1). 9.4 Sample Analysis--Purge the lines from the sample container through the sample loop in the gas chromatograph. Inject 1 cc with a gas sampling valve as in 8.2.1. If the sample size exceeds the linear range of the detector a split injection should be used. Run the analysis per the conditions specified in Table 1. Obtain the .chromatographic data via a potentiometric record (graphic), digital integrator, or corn-

10. Calculations 10.1 Determine the chromatographic peak area for components and use the response factors obtained from the calibration run to calculate amounts of sulfurs present. Example: Assume 1.0 ppmv of dimethyl sulfide, DMS, injected into a 1.0 cc sample loop with no split. 1 ppmv DMS = 2.54 mg/M 3 (Table 3) 2540 pg x 51.61% S ffi 1310 picog S/peak If area is found to be 15,850 counts-response factor picograms (S/peak) is 1310/15850 -- 8.27 x 10-2 (in terms of picograms sulfur per peak) or response factor (ppmv DMS sample) = 1.0/15850 = 63 x 10-6 (in terms of ppmv of sulfur compound in sample) NOTE 8--Since detector response is proportional to weight sulfm', all mono sulfur compounds (COS, H2S, DMS, etc.) will have approximately the same response factor for picograms S or ppmv (see 8.2.2).

920

I~) D 5504 11. Report 1 I. 1 Report the identification and concentration of each individual sulfur compound. The sum of all sulfur components detected to the nearest picogram, calculated as sulfur (pg S) can be used to calculate the total sulfur.

12. Precision and Bias 12.1 Precision--The precision of this test method as determined by the statistical examination of the interlaboratory test results is as follows: 12.1.1 Repeatability---The difference between successive test results obtained by the same operator with the same apparatus under constant operating conditions on identical test material would, in the long run, in the normal and

correct operation of the test method, exceed the following values by only one case in twenty. (Experimental results to be determined) 12.1.2 Reproducibility--The difference between two single and independent results obtained by different operators working in different laboratories on identical test matefial would, in the long run, exceed the following values only one case in twenty. (Experimental results to be determined) 12.2 B/as--The procedure in Test Method D 5504 for the analysis of sulfur compounds in petroleum and petroleum products by gas chromatography has no bias. 13. Keywords 13.1 chemiluminescence detection; gas chromatography; sulfur compounds

The American Society for Testmg and Materials takes no posltion respecting the vahdity of any patent rtghts asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the vahdlty of any such patent rtghts, and the risk of infringement of such rights, are entirely their own responsibility. This standard is sublect to revision at any time by the responsible technical committee and must be reviewed every hve years and if not revised, etther reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical commfftee, which you may attend. If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 100 Barr Harbor Drtve, West Conshohocken, PA 19428.

921

(t~T~ Designation: D 5580 - 95 Standard Test Method for Determination of Benzene, Toluene, Ethylbenzene, p/m-Xylene, o-Xylene, C9 and Heavier Aromatics, and Total Aromatics in Finished Gasoline by Gas Chromatography This standard is issued under the fixed designation D 5580; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsdon (c) indicates an editorial change since the last revision or reapproval.

1. Scope 1.1 This test method covers the determination of benzene, toluene, ethylbenzene, the xylenes, C9 and heavier aromatics, and total aromatics in finished motor gasoline by gas chromatography. 1.2 The aromatic hydrocarbons are separated without interferences from other hydrocarbons in finished gasoline. Nonaromatic hydrocarbons having a boiling point greater than n-dodecane may cause interferences with the determination of the C9 and heavier aromatics. For the C8 aromatics, p-xylene and m-xylene co-elute while ethylbenzene and o-xylene are separated. The C9 and heavier aromatics are determined as a single group. 1.3 This test method covers the following concentration ranges, in liquid volume %, tbr the preceding aromatics: benzene, 0.1 to 5 %; toluene, 1 to 15 %; individual C8 aromatics, 0.5 to 10 %; total C,) and heavier aromatics, 5 to 30 %, and total aromatics, l0 to 80 %. 1.4 Results are reported to the nearest 0.01% by either mass or by liquid volume. 1.5 Many of the common alcohols and ethers that are added to gasoline to reduce carbon monoxide emissions and increase octane, do not interfere with the analysis. Ethers such as methyl tert-butylether (MTBE), ethyl tert-butylether (ETBE), tert-amylmethylether (TAME), and diisopropylether (DIPE) have been found to elute from the precolumn with the nonaromatic hydrocarbons to vent. Other oxygenates, including methanol and ethanol elute before benzene and the aromatic hydrocarbons, l-Methylcyclopentene has also been found to elute from the precolumn to vent and does not interfere with benzene. 1.6 The values stated in SI units are to be regarded as standard. The values given in parentheses are provided for information only; they may not be exact equivalents. 1.7 This standard does not purport to address all of the

D 1298 Practice for Density, Relative Density, (Specific Gravity) or API Gravity of Crude Petroleum and Liquid Petroleum Products by Hydrometer Method 2 D 4052 Test Method for Density and Relative Density of Liquids by Digital Density Meter 3 D4057 Practice for Manual Sampling of Petroleum and Petroleum Products 3 D 4307 Practice for Preparation of Liquid Blends for Use as Analytical Standards 3 E 355 Practice for Gas Chromatography Terms and Relationships 4 3. Terminology

3.1 Descriptions of Terms Specific to Th& Standard." 3.1.1 aromatic--any organic compound containing a benzene ring. 3.1.2 low-volume connector--a special union for connecting two lengths of narrow bore tubing 1.6-mm (0.06-in.) outside diameter and smaller; sometimes this is referred to as zero dead volume union. 3.1.3 narrow bore tubingmtubing used to transfer components prior to or after separation; usually 0.5-ram (0.02-in.) inside diameter and smaller. 3.1.4 sprit ratio--in capillary gas chromatography, the ratio of the total flow of carrier gas to the sample inlet versus the flow of the carrier gas to the capillary column, expressed by: split ratio = ( S + ( ' ) / C (l) where: S = flow rate at the splitter vent and C = flow rate at the column outlet. 3.1.5 1,2,3-tris-2-cyanoethoxypropane (TCEP)--a polar gas chromatographic liquid phase. 3.1.6 wall-coated open tubular (WCOT)ma type of capillary column prepared by coating the inside wall of the capillary with a thin film of stationary phase.

sa.[~,ty concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

4. Summary of Test Method 4.1 A two-column chromatographic system equipped with a column switching valve and a flame ionization detector is used. A reproducible volume of sample containing an appropriate internal standard such as 2-hexanone is injected onto a precolumn containing a polar liquid phase

2. Referenced Documents 2.1 ASTM Standards: t This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcom. mittee D02.04.0L on Gas Chromatography. Current edition approved Sept. 10, 1995. Pubhshed November 1995. Originally published as D 5580 - 94. Last previous edition D 5580 - 94.

2 Annual Book of ASTM Standards, Vol 05.01 3 Annual Book of ASTM Standards, Vol 05.02. a Annual Book of ASTM Standards, Vol 14.02.

922

of precise control when column head pressures and flow rates are low. 6.1.2 Sample Introduction System, capable of introducing a representative sample into the gas chromatographic inlet. Microlitre syringes and automatic syringe injectors have been used successfully. 6.1.3 Inlet System, (splitting type)--Split injection is necessary to maintain the actual chromatographed sample size within the limits required for optimum column efficiency and detector linearity. 6.1.3.1 Some gas chromatographs are equipped with oncolumn injectors and autosamplers which can inject submicrolitre sample sizes. Such systems can be used provided that column efficiency and detector linearity are comparable to systems with split injection, 6.1.4 Detector--A flame ionization detector (Detector A) is employed for quantitation of components eluting from the WCOT column. The flame ionization detector used for Detector A shall have sufficient sensitivity and stability to detect 0.01 volume % of an aromatic compound. 6.1.4.1 It is strongly recommended that a thermal conductivity detector be placed on the vent of the TCEP precolumn (Detector B). This facilitates the determination of valve BACKFLUSH and RESET times (l 1.5) and is useful for monitoring the separation of the polar TCEP precolumn. 6.1.5 Switching and Backflushing Valve, to be located within a temperature-controlled heated zone and capable of performing the functions in accordance with Section I l, and illustrated in Fig. 1. The valve shall be of low internalvolume design and not contribute significantly to deterioration of chromatographic resolution. 6.1.5.1 A 10-port valve with 1.6-mm (0.06) outside diameter fittings is recommended for this test method. Alternately, and if using columns of 0.32-mm inside diameter or smaller, a valve with 0.8-mm (0.03-in.) outside diameter fittings should be used. 6.1.5.2 Some gas chromatographs are equipped with an auxiliary oven which can be used to contain the valve. In such a configuration, the valve can be kept at a higher temperature than the polar and nonpolar columns to prevent sample condensation and peak broadening. The columns are then located in the main oven and the temperature can be adjusted for optimum aromatic resolution. 6.1.5.3 An automatic valve switching device is strongly recommended to ensure repeatable switching times. 6.2 Data Acquisition System: 6.2.1 Integrator or Computer, capable of providing realtime graphic and digital presentation of the chromatographic data are recommended for use. Peak areas and retention times can be measured by computer or electronic integration. 6.2.1.1 It is recommended that this device be capable of performing multilevel internal-standard-type calibrations and be able to calculate the correlation coefficient (r 2) and linear least square fit equation for each calibration data set in accordance with 12.4. 6.3 Chromatographic Columns (two columns are used): 6.3. l Polar Precolumn, to perform a pre-separation of the aromatics from nonaromatic hydrocarbons in the same boiling point range. Any column with equivalent or better

(TCEP). The C 9 and lighter nonaromatics are vented to the atmosphere as they elute from the precolumn. A thermal conductivity detector may be used to monitor this separation. The TCEP precolumn is backflushed immediately before the elution of benzene, and the remaining portion of the sample is directed onto a second column containing a nonpolar liquid phase (WCOT). Benzene, toluene, and the internal standard elute in the order of their boiling points and are detected by a flame ionization detector. Immediately after the elution of the internal standard, the flow through the nonpolar WCOT column is reversed to backflush the remainder of the sample (C 8 and heavier aromatics plus C w and heavier nonaromatics) from the column to the flame ionization detector. 4.2 The analysis is repeated a second time allowing the C~2 and lighter nonaromatics, benzene and toluene to elute from the polar TCEP precolumn to vent. A thermal conductivity detector may be used to monitor this separation. The TCEP precolumn is backflushed immediately prior to the elution of ethylbenzene and the remaining aromatic portion is directed into the WCOT column. The internal standard and C8 aromatic components elute in the order of their boiling points and are detected by a flame ionization detector. Immediately after o-xylene has eluted, the flow through the nonpolar WCOT column is reversed to backflush the C,~ and heavier aromatics to the flame ionization detector. 4.3 From the first analysis, the peak areas of benzene, toluene, and the internal standard (2-hexanone) are measured and recorded. Peak areas for ethylbenzene, p/mxylene, o-xylene, the C9 and heavier aromatics, and internal standard are measured and recorded from the second analysis. The backflush peak eluting from the WCOT column in the second analysis contains only C9 and heavier aromatics. 4.4 The flame ionization detector response, proportional to the concentration of each component, is used to calculate the amount of aromatics that are present with reference to the internal standard.

5. Significance and Use 5.1 Regulations limiting the concentration of benzene and the total aromatic content of finished gasoline have been established for 1995 and beyond in order to reduce the ozone reactivity and toxicity of automotive evaporative and exhaust emissions. Test methods to determine benzene and the aromatic content of gasoline are necessary to assess product quality and to meet new fuel regulations. 5.2 This test method can be used for gasolines that contain oxygenates (alcohols and ethers) as additives. It has been determined that the common oxygenates found in finished gasoline do not interfere with the analysis of benzene and other aromatics by this test method. 6. Apparatus

6.1 Chromatographic System--See Practice E 355 for specific designations and definitions. Refer to Fig. 1 for a diagram of the system. 6. I. 1 Gas Chromatograph (GC), capable of operating at the conditions given in Table 1, and having a column switching and backfiushing system equivalent to Fig. I. Carrier gas pressure and flow control devices shall be capable 923

(@) D 5580 Valve on (Backflush)

Valve off (Reset) Capdlary Inlet

Capillary Inlet

TCEP Precolumn

TCEP Precolumn

Capill~w~u mr

) | 54

Secondary~ Flow

-

I

A (FID)

A (FID) Flow

FIG. 1

Vent or Detector B (TCD)

Valve Diagram, Aromatics in Gasoline

the carrier gas used must be 99.95 mol %. Additional purification may be necessary to remove trace amounts of oxygen.

chromatographic efficiency and selectivity in accordance with 6.3.1.1 can be used. 6.3. I. 1 TCEP Micro-Packed Column, 560-mm (22-in.) by 1.6-mm (%6-in.) outside diameter by 0.38-mm (0.015-in.) inside diameter stainless steel tube packed with 0.14 to 0.15 g of 20 % (mass/mass) TCEP on 80/100 mesh Chromosorb P(AW). This column was used in the cooperative study to provide the precision and bias data referred to in Section 15. 6.3.2 Nonpolar (Analytical) Column--Any column with equivalent or better chromatographic efficiency and selectivity in accordance with 6.3.2.1 can be used. 6.3.2.1 WCOT Methfl Silicone Cohonn, 30 m long by 0.53-mm inside diameter fused silica WCOT column with a 5.0-~tm film thickness of cross-linked methyl siloxane.

NOTE I: WarningmHelium is usually supplied as a compressed gas under high pressure. 7.2 Methylene Chloride--Used for column preparation. Reagent grade, free of nonvolatile residue. NOTE 2: Warning--Harmful when ingested or inhaled at high cencentrations. 7.3 2,2, 4- Trimethylpentane (isooctane)--Used as a solvent in the preparation of the calibration mixture. Reagent grade. NOTE 3: Warning--lsooctane is flammable and can be harmful or fatal when ingested or inhaled.

7. Reagents and Materials

7.1 Carrier Gas, appropriate to the type of detector used. Helium has been used successfully. The minimum purity of

1

7.4 Standards for Calibration and Identification, required for all components to be analyzed and the internal standard. Standards are used for establishing identification by retention time as well as calibration for quantitative measurements. These materials shall be of known purity and free of the other components to be analyzed.

Typical Chromatographic Operating Parameters Temperatures

Injection port (spht injector) FID (Detector A) TCD (Detector B) Nonpolar WCOT capillary InJtial Program rate Final

2000C 2500C 2000C

Polar TCEP precolumn (temperature to rema=n constant before t=me to BACKFLUSH, T1 or T2. Do not exceed maximum operating temperature.) Valve

NOTE 4: Warning--These materials are flammable and may be harmful or fatal when ingested or inhaled.

60"C (6 ram) 2*C/mfn 1150C (hold until all components elute) 600C or same as nonpolar WCOT capillary if TCEP/WCOT columns contained in ident=cal heated zone.

8. Preparation of Columns 8. I TCEP Column Packing." 8.1.1 Use any satisfactory method, that will produce a column capable of retaining aromatics from nonaromatic components of the same boiling point range in a gasoline sample. The following procedure has been used successfully. 8.1.2 Completely dissolve 10 g of TCEP in 100 mL of methylene chloride. Next add 40 g of 80/100 mesh Chromosorb P(AW) to the TCEP solution. Quickly transfer this mixture to a drying dish, in a fume hood, without scraping any of the residual packing from the sides of the container. Constantly, but gently, stir the packing until all of the solvent has evaporated. This column packing can be used immediately to prepare the TCEP column. 8.2 Micro-packed TCEP Column:

>115°C or same as nonpolar WCOT capdlary if valve and WCOT column contained in identical heated zone.

Flows and Conditions

Carrier gas Flow to TCEP precolumn (spilt rejector) Flow to WCOT capillary (auxiliary flow) Flow from split vent Detector gases Split ratio Sample size

~

¢ Vent or Detector B (TCD)

TABLE

C

Seconde

helium 10 mL/min 10 mL/min 100 mL/min as necessary 11 : 1 1 pL

924

( ~ D 5580 8.2.1 Wash a straight 560-mm (22-in.) lcngth of 1.6-mm (tA6-in.) outside diameter, 0.38-mm (0.015-in.) inside diameter stainless steel tubing with methanol and dry with compressed nitrogen. 8.2.2 Insert 6 to 12 strands of silvered wire, a small mesh screen or stainless steel frit inside one end of the tube. Slowly add 0.14 to 0.15 g of packing material to the column and gently vibrate to settle the packing inside the column. Insert silvered wire, mesh screen, or frit to the other end of the tube to prevent the packing material from falling. When strands of wire are used to retain the packing material inside the column, leave 6.0 mm (0.25 in.) of space at the top of the column. 8.3 WCOT Methyl Silicone Column--It is suggested that this column be purchased directly from a suitable capillary column manufacturer (see 6.3.2. I).

(first analysis) and ethylbenzene from the xylenes (second analysis). 11.3 Flow Rate (Carrier Gas) Adjustments: 11.3.1 Attach a flow measuring device to the precolumn vent (or Detector B) with the valve in the RESET or forward flow position and adjust the pressure of the capillary injection port (Fig. 1) to give 10.0-mL/min flow (17 to 20 psi). Soap bubble flow meters are suitable. This represents the flow through the polar precolumn. 11.3.2 Attach a flow measuring device to the split injector vent and adjust the flow from the split vent using the flow controller to provide a flow of 100 mL/min. Recheck the column vent flow set in 11.3.1 and adjust, if necessary. The split ratio should be approximately 11: I. 11.3.3 Switch the valve to BACKFLUSH position and adjust the variable restrictor to give the same precolumn vent flow set in 11.3.1. This is necessary to minimize flow changes when the valve is switched. 11.3.4 Switch the valve to the RESET position and adjust the auxiliary flow controller to give a flow of 10 mL/min at the Detector A (FID) exit. 11.4 Detector Setup---Depending on the particular type of instrumentation used, adjust the hydrogen, air, and makeup flows to the flame ionization detector and ignite the flame. If a thermal conductivity detector (Detector B) is being used to monitor the vent effluent in the valve RESET position, set the reference flow and turn on the detector circuit. 11.5 Valve Backflush and Reset Times: 11.5.1 The time to BACKFLUSH and RESET the valve will vary slightly for each column system and must be determined as described in 11.5.1.1, 11.5.1.2, and 11.5.1.3. The start time of the integrator or computer system and valve timer must be synchronized with the injection to accurately reproduce the backflush time. This procedure assumes that a thermal conductivity detector is installed on the precolumn vent line as Detector B (see 6.1.4.1). If a detector is not available, the appropriate valve BACKFLUSH times, T I and T2, must be determined experimentally. If the BACKFLUSH times, T I and T2, are not set correctly (switched too late), it is possible that part of the benzene and ethylbenzene peaks will be vented. 11.5.1.1 Adjust the valve to RESET (forward flow) and inject 1.0 pL of a blend containing approximately 5 % each of benzene, ethylbenzene, o-xylene, and 2-hexanone in isooctane. This mixture is used to set the valve timing, therefore, the exact concentration need not be known. Alternatively, the calibration mixture can be used for this test. Determine retention time in seconds at which benzene and ethylbenzene start to elute as measured by Detector B. Subtract 6 s from each of these and call these times to BACKFLUSH, TI and T2, respectively. The correct time for TI and T2 is just prior to the elution of benzene and ethylbenzene from the TCEP precolumn.

9. Column Conditioning 9.1 Both the TCEP and WCOT columns are to be briefly conditioned before use. Connect the columns to the valve (see Fig. 1 and 11.1) in the chromatographic oven. Adjust the carrier gas flows in accordance with 11.3 and place the valve in the RESET position. After several minutes, increase the column oven temperature to 120°C and maintain these conditions for 20 min. Cool the columns below 60"C before shutting off the carrier gas. 10. Sampling 10.1 Every effort should be made to ensure that the sample is representative of the fuel source from which it is taken. Follow the recommendations of Practice D 4057, or its equivalent, when obtaining samples from bulk storage or pipelines. 10.2 Appropriate steps should be taken to minimize the loss of light hydrocarbons from the gasoline sample to be analyzed. Upon receipt in the laboratory, chill the sample in its original container from 0 to 5"C (32 to 40*F) before and after sub-sampling is performed. 10.3 If necessary, transfer the chilled sample to a vaportight container and store at 0 to 5"C (32 to 40°F) until needed for analysis. 11. Preparation of Apparatus and Establishment of Conditions 11.1 AssemblynConnect the TCEP and WCOT column to the valve system (Fig. 1) using low-volume connectors and narrow bore tubing. It is important to minimize the volume of the chromatographic system that comes in contact with the sample, otherwise peak broadening will occur. 11.2 Initial Operating Conditions--Adjust the operating conditions to those listed in Table 1, but do not turn on the detector circuits. Check the system for leaks before proceeding further. 11.2.1 If different polar and nonpotar columns are used, or WCOT capillary columns of smaller inner diameter or different film thickness, or both, are used, it may be necessary to use different optimum flows and temperatures. 11.2.2 Conditions listed in Table 1 are applicable to the columns described in 6.3. If a WCOT column of a different film thickness is used, the conditions chosen for the analysis must sufficiently separate toluene from the internal standard

NOTE 5--Figure 2 is an example chromatogram illustrating the elution of a calibration mixture from the polar precolumn using the procedure described in 11.5.1.1. Times to BACKFLUSH, TI and T2, are indicated on the chromatogram. The times to BACKFLUSH, TI and T2, should be optimized for each chromatographic system. 11.5.1.2 Reinject the calibration blend and turn the valve to BACKFLUSH at time TI. When the internal standard peak (2-hexanone) returns to baseline switch valve back to 925

(i~ D 5580

2000.

iso-octane

Detector B (TCD)

1~00.

toluene

1000.

C8 aromatics

2-hexenone

~$00.

O.

•

-

-

,

1

0

FIG. 2

.

.

.

.

i

.

.

2

.

.

=

.

.

.

.

3

,

i

4

[5

Determination of Precolumn Backflush Times, T1 and T2

RESET (forward flow) position. Call this time T3. 11.5.1.3 Reinject the calibration blend and BACKFLUSH at time T2. When the o-xylene peak returns to baseline, switch the valve back to RESET (forward flow). Call this time T4. 11.6 Polar Precolumn Selectivity Check: 11.6.1 The selectivity of the polar precolumn is critical to allow for accurate determination of the C9 and heavier aromatics without non-aromatic interferences. The selectivity must be verified so that for the second analysis, when the time to BACKFLUSH T2 is properly adjusted, all of the Ciz and lighter non-aromatic hydrocarbons are vented from the polar precolumn while the heavier aromatics are retained. The following test can be used to verify the precolumn performance. 11.6.1.1 Prepare a blend containing approximately 1.5 % n-dodecane in 2,2,4-trimethylpentane (isooctane). nDodecane is used to represent the high boiling non-aromatic hydrocarbons in gasoline. Inject 1.0 IxL of the mixture under the conditions specified in 11.2 to 11.5 and actuate the valve at time T2 (BACKFLUSH) and time T4 (RESET). Record the signals from both the flame ionization (Detector A) and thermal conductivity (Detector B) detectors. Verify that n-dodecane fully elutes from the polar precolumn before BACKFLUSH time T2. When monitoring the thermal conductivity detector (Detector B), the n-dodecane peak should return to baseline before BACKFLUSH time T2. If not, part of the n-dodecane peak will be backflushed to the non-polar WCOT column and be detected by the flame ionization detector after the valve RESET time T4. If a thermal conductivity detector is not available on the precolumn vent line, the chromatogram obtained by the flame ionization detector can be used to verify that all the n-dodecane is being vented. This chromatogram should not show any significant response from n-dodecane after the RESET time T4. 11.6.1.2 If all of the n-dodecane peak is not completely vented from the polar precolumn, as measured by the

thermal conductivity or flame ionization detector, recheck instrument parameters and valve backflush times (11.5) or replace the polar precolumn. If the valve is contained in a separate isothermal heated zone, it may be necessary to use a higher temperature to prevent absorption of small amounts of n-dodecane on the rotor or transfer tubing surfaces. ! 2. Calibration

12.1 Preparation of Calibration Samples--Prepare multicomponent calibration standards of benzene, toluene, ethylbenzene, o-xylene, and 1,2,4-trimethylbenzene at concentrations of interest by mass in accordance with Practice D 4307. O-xylene is ~ to represent the xylenes while 1,2,4-trimethylbenzene is used for the C9 and heavier aromatics. For each aromatic component, use at least five calibration points and ensure that the concentration of each aromatic component is within its calibration range. For benzene, calibration concentrations of 0.1, 0.5, 1.0, 2.0, and 5 volume percent can be used. For toluene: 1.0, 2.5, 5.0, 10.0, and 15.0 volume %. For ethylbenzene, o-xylene, and 1,2,4-trimethylbenzene: 0.5, 1.0, 2.5, 5.0, and 10 volume % can be used. The relative densities listed in Table 2 shall be used as a guide in determining the proper mass of aromatic components that need to be added in order to arrive at a TABLE 2 Component Benzene Toluene Ethylbenzene p/ m-Xylene o-Xylene 1,2,4-Trimethylbanzene C9 plus aromatics 2-hexanone

Physical Constants Relative Density (15.56/15.56°C)A 0.8845 0.8719 0.8717 0.8679 0.8848 0,8806 0,8764 0.8162

A "Physical Constants of Hydrocarbons C1-Clo," STP 109A, ASTM, 1916 Race St., Philadelphia, PA 19103. The mixed xylene (p/m-xylene) density based upon a 1:3 ratio of p-xylene to m-xylene. Cg plus aromatics based upon the average relative density values of the 30 C9-Clo aromatics.

926

~) D 5580 TABLE 3

Benzene

~ 1.0 2.0 3.0 4.0 5.0

/ /

0.80

+ /

0

0.70 a$

0.60 h

0.50

0.30

/

0.20

~÷ O.lO

/

+

/

~

x2

y2

2.0 0.5 0.0 0.5 2.0

4.0 1.0 0.0 1.0 4.0

1,0 0.25 0.0 0.25 1.0

1.5 25.0 I0.0

~y2

= 2.5

r2

(~, x. y)2 (~ x2).(~ ~)

r2

25.0 (10.0)(2.5)

1.0

+

in accordance with the procedure in 12.4. Measure the peak areas of benzene, toluene, and internal standard peaks from the first analysis. From the second analysis measure the peak areas of internal standard, ethylbenzene, o-xylene, and 1,2,4-trimethylbenzene. Determine the response ratio (rsp,) and amount ratio (amt,) for each component in each standard using Eqs 2 and 3. rsp i = (Ai/As) (2)

rsp r a t i o = 1.41(amt ratio) + 0.00181 r ^ 2 = 1.000

+

0.00 0.000

1.0 -0.5 0.0 0.5 1,0

=3

• x2

0.40 /

y=~-~

-2.0 -1.0 0.0 1.0 2.0

0.5 1.0 1.5 2.0 2,5 = = =

(~ xy) 2

ExampleofDataSetforr2Calculation A x=~-£

0500

o.~oo

o.loo

amt ratio FIG. 3

where:

Typical Benzene Calibration Curve

A i = area of aromatic component, and A s = area of internal standard.

target volume percent concentration. 12.2 Before preparing the standards, determine the purity of the aromatics by capillary GC and make corrections for the impurities found. Whenever possible, use stocks of at least 99.9 % purity. 12.3 Prepare standards by transferring a fixed volume of aromatic component using pipettes, eye droppers, or syringes to 100-mL volumetric flasks or 100-mL septum-capped vials as follows. Cap and record the tare weight of the volumetric flask or vial to 0.1 rag. Remove the cap and carefully add the aromatic components to the flask or vial starting with the least volatile (1,2,4-trimethylbenzene). Cap the flask and record the net mass (Wi) of the aromatic component added to 0.1 mg. Repeat the addition and weighing procedure for each aromatic component. Do not exceed 50 volume % for all aromatics added. Similarly, add 10 m L of the internal standard, 2-hexanone, and record its net mass (Ws) to 0.1 mg. Dilute each standard to the mark with aromatics free 2,2,4-trimethylpentane (isooctane). Store the capped calibration standards in a refrigerator at 0 to 5"C (32 to 40*F) when not in use. 12.4 Calibration P r o c e d u r e m W i t h the valve initially in the RESET mode, chromatograph each of the calibration mixtures (12.1) twice using valve timing procedures in accordance with 11.5. For the first analysis use times T I (BACKFLUSH) and T3 (RESET) to actuate the valve. For the second analysis use times T2 (BACKFLUSH) and T4 (RESET) to actuate the valve.

amt, = ( W i / H ~ )

where: W i = mass of aromatic component, and W s = mass of internal standard. 12.4.1.1 Prepare a calibration curve for each aromatic component by plotting the response ratios (rsp~), as the y-axis, versus the amount ratios (amt,), as the x-axis. Figure 3 is an example of such a plot. 12.4.1.2 Calculate the correlation coefficient r 2 value for each aromatic component in the calibration using Eq 4. The r 2 value should be at least 0.990 or greater. If the above criteria for r 2 is not met, rerun the calibration or check instrument parameters and hardware. r2 =

(~ xy) 2

(4)

(Z x2)(~ j,2) where: x = xi - x y = Yi - .~

(5) (6)

and: X, = a m t ratio data point,

= average values for all amti data points, ]I,. = corresponding rspi ratio data point, and = average values for all rsp~ data points. 12.4.1.3 Table 3 gives an example on the calculation o f r 2 for an ideal data set. 12.4.2 L i n e a r L e a s t S q u a r e F i t - - F o r each aromatic i calibration data set, obtain the linear least square fit equation in the form:

NOTE 6--The first analysis is used to calibrate the gas chromatograph for benzene and toluene. The second analysis is used to calibrate for ethylbenzene, the xylenes (o-xylene), and the C9 and heavier aromatics ( 1,2,4-trimethylbenzene).

12.4.1 L i n e a r i t y T e s t ~ A n a l y z e

(3)

(rspi) = (mi)(amt ,) + b I

the calibration standards

where: 927

(7)

I ~ D 5580 TABLE 4

rsPi ---- response ratio for aromatic i (y-axis),

m;

= slope of linear equation for aromatic i, amti -- a m o u n t ratio for aromatic i (x-axis), and bi = y-axis intercept. 12.4.2.1 The values m i and b i are calculated as follows:

Component

m, = ~ xy/rZ x ~

(8)

b, = ~ - m?7

(9)

Benzene Toluene Ethylbenzene P/M-xylene O-xylene C9 plus aromatics Total aromatics

and: 12.4.2.2 For the example in Table 3

TABLE 5

m, = 5/10 = 0.5

Repeatability Estimates for Aromatics in Gasoline

1.5 - (0.5)(3)

=

0

Benzene Toluene Ethylbenzene P/M-xylene O-xylene C9 plus aromatics Total aromatics

(l 1)

12.4.2.3 Therefore, the least square equation (7) for the example in Table 3 is: (12)

(rsp,) = 0.5(amt,) + 0

NOTE 7--Normally the b, value is not zero and can be positive or negative. Figure 3 gives an example of linear least square fit for benzene and the resulting equation in the Eq 7. 12.4.3 Y-Intercept T e s t - - F o r an o p t i m u m calibration, the absolute value of the y-intercept (b,) must be at a m i n i m u m . In this case, Ai approaches zero when w, is less than 0.1 mass %. In practice, this means the mass % (w,) calculated for an aromatic with zero peak area must be close to zero. The equation to determine the mass % aromatic i, or w,, reduces to Eq 13. The y-intercept can be tested using 13 below: w,

=

(b,/m,)( Ws/Wg)100 %

(13)

where: wi = mass % aromatic i, Ws = mass of internal standard added, g, and Wg = mass of gasoline samples, g.

0.0265 (Xo-ss) 0.0301 (X°.s) 0.029 0,071 0.0296 (Xo 5) 0.0145 (X+5,157) 0.46

R a n g~,) e, (mass

Reproducibility (X = mass %)

0.14-1.79 2.11-10.08 0.57-2.65 2.06-9.59 0.77-3.92 8.32-25.05 16.34-49.07

0.1229 (X° es) 0.0926 (X° s) 0.163 0.452 0.1168 (X°.s) 0.070 (X+5.157) 1.59

values exceed the mass % limit, rerun the calibration procedure for aromatic i, or check instrument parameters and hardware. The following gives an example o f the calculation for the y-intercept (b,) test using the data from Fig. 3 for aromatic i (benzene) for which b, = 0.0018 and m, = 1.41. From 13.1, a typical sample preparation may contain approximately Ws = 0.8 g(1.0 mL) of internal standard and Wg = 6.75 g (9.0 mL) of a gasoline sample. Substituting these values into Eq 13 yields: w, = (0.0018/1.41)(0.8/6.75)100 % w, = 0.01 mass %

For benzene, w, must be less than 0.02 mass %. For the other aromatics, w, must be less than 0.2 mass %. If any of the w,

13. Procedure 13.1 Preparation o f S a m p l e - - T r a n s f e r 1 m L o f internal 2

3

4

I.

1. benzene 2. toluene 3.2-hexsnone (ISTD) 4. backflush peek (C8 plus aromatics and C9 plus non-aromatic hydrocarbons)

iiii 1

1.0~e

o

i

o

• c5

FIG. 4

A .

, 10

(14)

Since w, is less than 0.02 mass %, the y-intercept (b,) has an acceptable value for benzene. Similarly, determine w, for all other aromatics.

NOTE 8mSince in practice Ws and Wg vary slightly from sample to sample, use an average value as indicated below.

6"Oe

0.14-1.79 2.11-10.08 0.57-2.65 2.06-9.59 0.77-3.92 8.32-25,05 16.34-49.07

Reproducibility Estimates for Aromatics in Gasoline

Component =

Repeatability (X = mass %)

(10)

and b,

R a n g~,) e, (mass

. . . .

, 18

. . . .

i, ~O

Aromatics in Gasoline, Analysis No. 1

928

-

-

~

1. 2. 3. 4. 5.

D 5580

2-hexanone (ISTD)

ethylbanzene p/m.xylene o-xylene C 9 plus aromatics

-,A..0 e a

3.0e~

2.0

ew'~

1 .oe(~

T2 o o

1

T4

_1 ~.'0

~o

~o

~o

FIG. 5 Aromaticsin Gasoline,AnalysisNo. 2 standard (Ws) by a volumetric pipette into a tared and capped 10-mL volumetric flask or capped vial. Record the net mass of the internal standard added to the nearest 0.1 mg. Retare the capped flask or vial. Fill the volumetric flask or vial with 9 mL of chilled sample, cap, and record the net mass (Wg) of the sample added. Mix thoroughly. If using an automatic sampler then transfer an aliquot of the solution into a glass GC vial. Seal the GC vial with a TFEfluorocarbon-lined cap. If the sample is not immediately analyzed, store at 0 to 5°C (32 to 40°F). 13.2 Chromatographic Analysis--Introduce an aliquot of the sample, containing internal standard, into the gas chromatograph using the same technique and sample size as used for the calibration analysis. An injection volume of 1 gL with a 11:1 split ratio has been used successfully. Chromatograph the sample twice using valve timing procedures in accordance with 11.5. Use times T1 and T3 for the first analysis to BACKFLUSH and RESET the valve. Use times T2 and T4 for the second analysis. t3.3 Interpretation of Chromatogram--Compare the retention times of sample components to those of the calibration analysis to determine the identities of the aromatics. Identify benzene, toluene, and the internal standard from the first analysis. Identify the internal standard, ethylbenzene, p/m-xylene, o-xylene, C9 and heavier aromatic composite from the second analysis. Refer to Figs. 4 and 5 for sample chromatograms.

where: Wi = mass of aromatic component i, Ai -- area of aromatic component i, As = area of internal standard, and Ws = mass of internal standard added. 14.1.1 To obtain mass percent (w;) results for each component:

wi(100) wg

w, = ~

(I 6)

where: Wg = mass of gasoline sample. 14.1.2 Report the mass percent (w,) results of the following aromatics to the nearest 0.10 %; benzene, toluene, ethylbenzene, p/m-xylene, o-xylene, C9 and heavier aromatics. 14.1.3 To obtain the total mass percent aromatics, sum the mass percent (w,) results of all the individual aromatic components i. 14.2 Volumetric Concentration of Aromatic Components--If the volumetric concentration of each aromatic component i is desired, calculate the volumetric concentration in accordance with Eq 15:

,,7,

14. Calculation and Report 14.1 Mass Concentration of Aromatics--After identifying the peaks, measure the areas of benzene, toluene, and the internal standard from the first analysis and the internal standard, ethylbenzene, p/m-xylene, o-xylene, C9 and heavier aromatics from the second analysis. Using the slope and y-intercept of the least square fit calibrations in 12.4.2, calculate the mass of each aromatic component (Wi) in the gasoline samples using the response ratio (rsPi) of the areas of the aromatic component to the internal standard as follows:

where: v, = volume percent of each aromatic component to be determined, Dj -- relative density of the fuel under study as determined in accordance with Practice D 1298 or Test Method D 4052, and D, = relative density at 15.56°C (60°F) of the individual aromatics (Table 2).

929

t~ D 5580 apparatus under constant operating conditions on identical test materials would, in the long run, in the normal and correct operation of the test method exceed the following values in only one case in twenty. See Table 4. 15.1.2 Reproducibility--The difference between two single and independent results obtained by different operators working in different laboratories on identical material, would in the long run, exceed the following values in one case in twenty. See Table 5. 15.1.3 Bias--Since there is no accepted reference material suitable for determining bias for the procedure in this test method, no statement of bias is being made.

14.2.1 Report the volume percent results (Vl) of the following aromatic components to the nearest 0.01%; benzene, toluene, ethylbenzene, p/m-xylene, o-xylene, and C9 and heavier aromatics. 14.2.2 To obtain total volume percent aromatics, sum the volume percent (v,) results of all the individual aromatic components i. 15. Precision and Bias s 15.1 Precision--The precision of this test method as determined by the statistical examination of the interlaboratory test reports is as follows: 5 15.1.1 Repeatability--The difference between successive test results obtained by the same operator with the same 5 Supporting data are available from ASTM headquarters. D02-1329.

16. Keywords 16.1 aromatics; benzene; ethylbenzene; gas chromatography; gasoline; toluene; xylenes

Request RR:

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted m connection with any item mentioned in this standard Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility This standard is sublect to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reapproved or withdrawn Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 100 Barr Herbor Drive, West Conshohocken, PA 19428,

930

4~1~ Designation: D 5599 - 95

Standard Test Method for Determination of Oxygenates in Gasoline by Gas Chromatography and Oxygen Selective Flame Ionization Detection This standard is issued under the fixed designation D 5599; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (~) indicates an editorial change since the last revision or reapproval.

E 594 Practice for Testing Flame Ionization Detectors Used in Gas Chromatography 4 E 1064 Test Method for Water in Organic Liquids by Coulometric Karl Fischer Titration 5 E 15 l0 Practice for Installing Fused Silica Open Tubular Capillary Columns in Gas Chromatographs 4

1. Scope 1.1 This test method covers a gas chromatographic procedure for the quantitative determination of organic oxygenated compounds in gasoline having a final boiling point not greater than 220"C and oxygenates having a boiling point limit of 130"C. It is applicable when oxygenates are present in the 0. l to 20 % by mass range. 1.2 This test method is intended to determine the mass concentration of each oxygenate compound present in a gasoline. This requires knowledge of the identity of each oxygenate being determined (for calibration purposes). However, the oxygen-selective detector used in this test method exhibits a response that is proportional to the mass of o.~:vgen. It is, therefore, possible to determine the mass concentration of oxygen contributed by any oxygenate compound in the sample, whether or not it is identified. Total oxygen content in a gasoline may be determined from the summation of the accurately determined individual oxygenated compounds. The summed area of other, uncalibrated or unknown oxygenated compounds present, may be converted to a mass concentration of oxygen and summed with the oxygen concentration of the known oxygenated compounds. 1.3 The values stated in SI units are to be regarded as the standard. 1.4 This standard does not purport to address all of the

3. Terminology

3.1 Definitions: 3.1.1 independent reference standardsqcalibration samples of the oxygenates which are purchased or prepared from materials independent of the quality control check standards and used for intralaboratory accuracy. 3.1.2 oxygenate, n - - a n oxygen-containing compound, such as an alcohol or ether, which may be used as a fuel or fuel supplement. D 4175 3.1.3 quality control check standards--calibration samples of the oxygenates for intralaboratory repeatability. 4. Summary of Test Method 4.1 An internal standard of a noninterfering oxygenate, for example, 1,2-dimethoxyethane (ethylene glycol dimethyl ether) is added in quantitative proportion to the gasoline sample. A representative aliquot of the sample and internal standard is injected into a gas chromatograph equipped with a capillary column operated to ensure separation of the oxygenates. Hydrocarbons and oxygenates are eluted from the column, but only oxygenates are detected with the oxygen-selective flame ionization detector (OFID). A discussion of this detector is presented in Section 6. 4.2 Calibration mixtures are used for determining the retention times and relative mass response factors of the oxygenates of interest. Suggested calibrant materials are listed in 8.2. 4.3 The peak area of each oxygenate in the gasoline is measured relative to the peak area of the internal standard, A quadratic least-squares fit of the calibrated data of each oxygenate is applied and the concentration of each oxygenate calculated.

saJL,ty concerns, if any. associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 2. Referenced Documents

2.1 ASTM Standards: D 1744 Test Method for Water in Liquid Petroleum Products by Karl Fischer Reagent 2 D4175 Terminology Relating to Petroleum, Petroleum Products, and Lubricants 3 D 4307 Practice for Preparation of Liquid Blends for Use as Analytical Standards 3 D 4626 Practice for Calculation of Gas Chromatographic Response Factors 3

NOTE l - - W h i l e

1,2-dimethoxyethane has been found to be an

appropriate internal standard, other oxygenatesmay be used provided they are not present in the sample and do not interfere with any compound of interest.

5. Significance and Use 5.1 In gasoline blending, the determination of organic

This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02,04.0L on Gas Chromatography. Current edition approved Sept. 10, 1995. Published November 1995. Originally published as D 5599 - 94. Last previous edition D 5599 - 94. 2 ,,Innual BtuJk ofASTM Standard~', Vol 05.01. 3 Annual Book of ASTM Standards, Vol 05.02.

4 Annual Book ~fASTM Standards, Vol 14.02. 5 Annual Book of ASTM Standards° Vol 15.05.

931

t~

O 5599

analyzed before the catalyst needs replacement.

oxygenated compounds is important. Alcohols, ethers, and other oxygenates are added to gasoline to increase the octane number and to reduce tailpipe emissions of carbon monoxide. They must be added in the proper concentration and ratios to meet regulatory limitations and to avoid phase separation and problems with engine performance or efficiency. 5.2 This test method provides sufficient oxygen-to-hydrocarbon selectivity and sensitivity to allow determination of oxygenates in gasoline samples without interference from the bulk hydrocarbon matrix.

7. Apparatus

6. Theory of OFID Operation 6.1 The detection system selective for organic oxygen consists of a cracking reactor, hydrogenating reactor (methanizer), and a flame ionization detector (FID). The cracking reactor, connected immediately after the gas chromatographic capillary column, consists of a Pt/Rh capillary tube. Carbon monoxide (CO) is formed from compounds containing oxygen according to the following reaction: CxHyOz --* zCO + (y/2)H 2 + (x - z)C (1) 6.2 An excess layer of carbon is created in the Pt/Rh tube of the cracking reactor from the introduction of hydrocarbons from the sample or, if so designed, from a hydrocarbon (for example, pentane or hexane) doping system, or both. This layer of carbon facilitates the cracking reaction and suppresses hydrocarbon response. 6.3 The carbon monoxide formed in the cracking reactor is converted to methane in the hydrogenating reactor according to the following reaction: CO + 3H 2 --, CH4 + H20

(2)

The CH 4 is subsequently detected with an FID. 6.4 The methanizer consists either of a short porous layer open tubular (PLOT) glass capillary tube internally coated with aluminum oxide with adsorbed nickel catalyst or stainless steel tubing containing a nickel-based catalyst. It is installed within or before the FID and is operated in the range from 350 to 450*C, depending on the instrument's manufacturer. NOTE 2--Gasolines with high sulfur content may cause a loss in detector sensitivitythereby hmiting the number of samples that can be

~

Carrier gas

7.1 Gas Chromatograph--Any gas chromatograph can be used having the following performance characteristics: 7. I . l Cohtmn Temperature Programmer--The chromatograph must be capable of reproducible linear temperature programming over a range sufficient for separation of the components of interest. 7.1.2 Sample Introduction System--Any system capable of introducing a representative 0.1 to 1.0-1aL liquid sample into the split inlet device of the gas chromatograph. Microlitre syringes, autosamplers, and liquid sampling valves have been used successfully. The split injector should be capable of accurate split control in the range from 10:l to 500:1. 7.1.3 Carrier and Detector Gas Control--Constant flow control of carrier and detector gases is critical to optimum and consistent analytical performance. Control is best provided by the use of pressure regulators and fixed flow restrictors. The gas flow rates are measured by any appropriate means. The supply pressure of the gas delivered to the gas chromatograph must be at least 70 kPa (l 0 psig) greater than the regulated gas at the instrument to compensate for the system back pressure. In general, a supply pressure of 550 kPa (80 psig) will be satisfactory. 7.2 OFID Detector System, consisting of a cracking reactor, methanizer, and FID. A schematic of a typical OFID system is shown in Fig. I. 7.2.1 The detector must meet or exceed the typical specifications given in Table l of Practice E 594 while operating in the normal FID mode as specified by the manufacturer. 7.2.2 In the OFID mode, the detector shall meet or exceed the following specifications: (a) equal to or greater than l03 linearity, (b) less than 100-ppm mass oxygen (l-ng O/s) sensitivity, (c) greater than l06 selectivity for oxygen compounds over hydrocarbons, (d) no interference from coeluting compounds when 0. I to 1.0-1xL sample is injected, (e) equimolar response for oxygen. 7.3 Column--A 60-m by 0.25-mm inside diameter fused silica open tubular column containing a 1.0-1xm film thickness of bonded methyl silicone liquid phase is used. Equiva-

SampleCn HmOx Crackirrg reactor

Methanizer

FID

1300"(

Pt/n_.__hh

~

meter

-0 L (H2) Air

Capillarycolumn •

4

If designed FIG. 1 Schematicof an OFID

932

H2

~ TABLE 1

D 5599 all other oxygenates present (for example, 1,2-dimethoxyethane). 8.4 Dopant--If the OFID is so designed, reagent-grade pentane is used as a hydrocarbon dopant for the cracking reactor.

Typical Operating Conditions

Temperatures, °C Injector Column Detector Methantzer Reactor

250 50°C (hold 10 rain), ramp 8°/rain to 250°C 350-450 850-1300

NOT~ 4: Warning--Pentane is extremely flammable and harmful when inhaled.

Flows, mL/mln Column carrier gas Detector gases Auxlhary (for dopant, if available)

1 Atr: 300 H2 30 H2:0 6

Sample Stze Spht Ratio

0.1-1.0 p.LA 100-1

8.5 Instrument GaseswThe gases supplied to the gas chromatograph and detector arc: 8.5.1 Air, zero grade. NOTE 5: Warning--Compressedair is a gas under high pressure and supports combustion. 8.5.2 Hydrogen, pure grade, 99.9 mol %.

A Sample size and split ratio must be adjusted so that the oxygenates in the range from 0.1 to 20.0 mass • are eluted from the column and measured linearly at the detector. Each laboratory must establish and monttor the conditions that are needed to maintain linearity with their individual instruments. Nonlinearity is most commonly observed when using an OFID with samples containing high levels of individual oxygenates and can be compensated for by either decreasing the sample size, increasing the split ratio, or diluting the sample with an oxygenatefree gasoline. A sample size of 0.5 p.L and a split ratio of 100:1 has been used successfully in most cases.

NOTE 6: Warning--Hydrogen is an extremely flammable gas under high pressure.

8.5.3 Helium or nitrogen as column carder gas, 99.995 mol % minimum purity, or a blend of 95 % helium/5 % hydrogen, depending on the instrument's manufacturer. NOT~ 7: Warning--Helium and nitrogen are compressed gases under high pressure.

lent columns which provide separation of all oxygenates of interest may be used. 7.4 Integrator~Use of an electronic integrating device or computer is required. The device and software should have the following capabilities: 7.4.1 Graphic presentation of the chromatogram, 7.4.2 Digital display of chromatographic peak areas, 7.4.3 Identification of peaks by retention time, 7.4.4 Calculation and use of response factors, and 7.4.5 Internal standard calculation and data presentation.

8.5.4 Additional purification of the carder, air, and hydrogen is recommended. Use molecular sieves, Drierite, charcoal, or other suitable agents to remove water, oxygen, and hydrocarbons from the gases. 8.6 Sample Container--Glass vials with crimp on or screwdown sealing caps with self-sealing polytetrafluoroethylene (PTFE)-faced rubber membranes are used to prepare calibration standards and samples for analyses.

9. Preparation of Apparatus 9.1 Chromatograph and OFID--Place instrument and detector into operation in accordance with the manufacturer's instructions. Install the capillary column according to Practice E 1510. Adjust the operating conditions to provide for separation of all oxygenates of interest. Typical conditions used with the column specified in 7.3 are listed in Table 1. 9.2 System Performance--At the beginning of each day of operation, inject an oxygenate-free gasoline sample into the chromatograph to ensure minimum hydrocarbon response. If hydrocarbon response is detected, the OFID is not operating effectively and must be optimized according to the manufacturer's instructions before the sample can be analyzed.

8. Reagents and Materials 8. l Purity of Reagents--Reagents grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, where such specifications are available. 6 Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination. 8.2 Calibrant MaterialswThe following compounds may be used for calibrating the detector: methanol, ethanol, n-propanol, iso-propanol, n-butanol, tert-butanol, secbutanol, iso-butanol, tert-pentanol, methyl lert-butylether (MTBE), tert-amylmethylether (TAME), ethyl tertbutylether (ETBE), di-iso-propylether (DIPE). NOTV 3: Warning--These materials are very flammable and may be harmful or fatal when ingested, inhaled, or allowed to be absorbed through the skin.

8.3 Internal Standard--Use one of the compounds listed in 8.2 that is not present in the sample. If all of the materials in 8.2 are likely to be present in the test sample, use another organic oxygenate of high-grade purity that is separated from 6 Reagolt ChemicaL~. Amerwan Chemical Society Spectllcattons, American Chemical Society, Washington, DC. For suggestionson the testing of reagents not hstcd by tile American Chemical Society, see Analar Stamlards/or Laboratory C'hemwal~, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia aml National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockvillc. MD.

933

10. Calibration and Standardization I O. 1 Retention Time Identification--Determine the retention time of each oxygenate component by injecting small amounts either separately or in known mixtures. Table 2 gives typical retention times for the oxygenates eluting from a 60-m methyl silicone column temperature programmed according to conditions given in Table 1. A chromatogram of a blend of oxygenates is given in Fig. 2. 10.2 Preparation of Calibration Samples--The calibration samples are prepared gravimetrically in accordance with Practice D4307 by blending known weights of organic oxygenate compounds (such as listed in 8.2) with a known weight internal standard and diluting to a known weight with an oxygenate-free gasoline. The calibration samples should contain the same oxygenates (in similar concentrations) as

~

D 5599 oxygenate to the nearest 0.1 mg. Repeat this process for any additional oxygenates of interest except the internal standard. Add oxygenate-free gasoline to dilute the oxygenates to the desired concentration. Record the mass of gasoline added to the nearest 0. l mg, and determine and label the standard according to the mass % quantities of each oxygenate added. These standards are not to exceed 20 mass % for any individual pure component due to potential hydrocarbon breakthrough or loss, or both, of calibration linearity. To minimize evaporation of light components, chill all chemicals and gasoline used to make standards. 10.2.2 Add a quantity of an internal standard (such as 1,2-dimethoxyethane) and reweigh the contents. Record the difference in masses as the mass of internal standard to the nearest 0.1 mg. The mass of the internal standard should be between 2 and 6 % of the mass of the calibration sample. 10.2.3 Ensure that the prepared standard is thoroughly mixed, and transfer approximately 2 mL of the solution to a vial compatible with the autosampler if such equipment is used. 10.2.4 At least five concentrations of each of the expected oxygenates should be prepared. The standards should be as equally spaced as possible within the range and may contain more than one oxygenate. A blank for zero concentration assessments must also be included before each standard. Additional standards should be prepared for other oxygenates of concern. 10.3 S t a n d a r d i z a t i o n - - R u n the calibration samples and establish the calibration curve for each oxygenate. The area under each peak in the resulting chromatogram is considered a quantitative measure of the corresponding compound. Using the peak area of each oxygenate and the internal standard, calculate the relative mass response factor for each oxygenate (relative to the internal standard) in accordance with Practice D 4626 and Eq 3:

E

,

¢

I 0.0

5.0

s ~

10.0 15.0 Time (minutes)

20.0

NOTE--Operating conditions ~n accordance with Table 1. FIG. 2

Chromatogram of an Oxygenates Blend

at:e expected in the sample under test. Before preparing the standards, determine the purity of the oxygenate stocks and make corrections for the impurities found. Whenever possible, use stocks of at least 99.9 % purity. Correct for the purity of the components for water content determined by Test Method D 1744 or Test Method E 1064. Quality control check standards may be prepared from the same oxygenate stocks and by the same analyst. Quality control check standards must be prepared from separate batches of the final diluted standards. 10.2.1 Tare a glass sample container and its PTFE-faced rubber septum sealing cap. Transfer a quantity of an oxygenate to the sample container and record the mass of the

RF~. = (WJA,)(A,/IV,)

where: RF~ = relative mass response factor of the test oxygen

compound, mass of the test oxygen compound in the calibration sample, g, w , = mass of the internal standard in the calibration sample, g, A s = peak area of the test oxygen compound in the calibration sample, and A i = peak area of the internal standard in the calibration sample. Since five concentrations of each expected oxygenate are used, calculate the response factors for all five concentration levels and take the averaged value as the relative mass response factor of the test oxygen compound. 10.3.1 Plot the response ratio (rsp,):

TABLE 2 Oxygenates Retention Times, Relative Response Factors, and Molecular Masses (Conditions as in Table 1) Compound D~ssolved Oxygen Water Methanol Ethanol Isopropanol tea-Butanol n-Propanol MTBE sec-Butanol DIPE Isobutanol ETBE tert-Pentanol 1,2-dJmethoxyethane n-Butanol TAME

Retent=on Time m=n

Molecular Mass

5.33 5.89 6.45 7.71 8.97 10.19 11.76 12.73 13.92 14,53 15.32 15.49 15.97 16.57 17.07 18.23

32.0 18.0 32.0 46.1 60.1 74 1 60.1 88.2 74,1 102.2 74.1 102.2 88.1 90.1 74.1 102.2

Ws

Relative Relative Response Response FactorsA.a Factorsa.C O D 0.70 0.99 1 28 1.63 1.30 1.90 1.59 2.26 1.64 2.25 2.03 1.00 1.69 2.26

(3)

D D 0.98 0.97 0.96 0.99 0.98 0.97 0.97 1.00 0,99 0.99 1,04 1.00 1.03 1.00

rsps = (As/A i)

(4)

as the y-axis versus amount ratio (amt~): amt~ = (Ws/Wi)

'~ Based on mass percent oxygenate compound basis. n Relattve to 1,2-dimethoxyethane. c Based on mass percent oxygen basis. o Not determined.

(5)

as the x-axis calibration curves for each oxygenate. Check the correlation ta value for each oxygenate calibration. The ra value should be at least 0.99 or better. 934

D 5599

~) TABLE 3

Precision Interval as Determined from Cooperative Study Data Repeatability

Component

Repeatability

Wt %

MeOH

0.20 0.50 1.00 2.00 3.00 4.00 500 6.00 10.00 12.00 14.00 16 00 20.00

0.03 0.05 0 07 0 10 0.12 0,13 0.15 0.17 0.22 0.24 . . . . . .

EtOH

iPA

tBA

0.01 0.02 0 02 0 03 0.03 0.04 0.06 0.06 0.06 0.07 0.11 0.08 0.13 0,09 0.16 0.10 0.25 0.14 0.29 0.15 . . . . . . . . . . . . . . . . . . . . . . . . . .

nPA

0.02 0.02 0.03 0 03 0.05 0.04 0.08 0.05 0.10 0.06 0,12 0,06 0.14 0.07 0.16 0.07 0.22 0.09 0.25 0.09 . . . . . . . . . . . .

MTBE

sBA

DIPE

IBA

ETBE

tAA

nBA

0.02 0.03 0.05 0,07 0.09 0.11 0.13 0.14 0.19 0.21 0.23 0.25 0.28

0.01 0 02 0.03 0.04 0.05 0.06 0.07 0.08 0,10 0.11 ... ... ...

0.02 0.03 0,05 0.08 0.10 0.12 0.14 0.16 0.22 0.25 0.28 0.30 0.35

0.01 0.02 0.03 0.05 0.07 0.09 0.11 0.12 0.18 0.21 ... .,. ...

0.01 0.01 0.04 0,07 0.10 0.13 0,16 0.19 0.29 0.34 0.39 0.43 0.53

0,03 0.03 0.04 0.04 0.05 0.06 0.07 0.08 0.08 0,10 0.09 0.11 0.10 0.13 0.10 0.14 0.13 0.17 0.14 0.19 . . . . . . . . . . . . . . . . . .

TAME 0.02 0.03 0.04 0.06 0,06 0.09 0.10 0.11 0.15 0.17 0.18 0.20 0.23

Total Oxygen ... 0.03 0.05 0.08 0.11 0.13 . .. ... . .. ... .. . .

Reproducibility Component Wt %

MeOH

EtOH

iPA

0.20 0.50 1.00 ZOO 3.00 4.00 5.00 6.00 10.00 1,2.00 14.00 16.00 20.00

0.06 0.14 0.25 0.45 0.64 0.82 1.00 1.17 1.81 2.12 . .

0.06 0.13 0.21 0.35 0.47 0.59 0.69 0.79 1.15 1.32 . . .

tBA

nPA

MTBE

sBA

DIPE

iBA

ETBE

tAA

0.05 0.11 0.20 0.28 0.48 0,61 0.72 0.84 1.26 1.46 . . .

0.04 0.09 0 17 0.31 0.45 0.58 0.70 0.82 1.29 1.51

0.02 0.05 0.10 0.19 0.28 0.37 0.46 0.55 0,89 1.06 1.23 1.39 1.72

0.05 0.10 0.17 0.28 0.38 0.47 0.55 0.63 0.91 1.04 ..• •,• • . .

0.05 0.10 0.16 0.26 0.35 0.43 0.50 0.57 0.82 0.93 1.04 1.15 1.34

0.05 0.11 0.19 0.34 0,47 0,60 0.72 0.84 1,28 1.49 ••• ••,

0.07 0.14 0.25 0.43 0.60 0.75 0.89 1.03 1.54 1.78 2.01 2.23 2.66

0.07 0.14 0.12 0.18 0.18 0.22 0.26 0.27 0.33 0.31 0.39 0.33 0.44 0.36 0.48 0.38 0.64 0.44 0.71 0.46 . . . . . . . . . . . .

.

0.07 0.16 0.27 0.47 0.65 0.82 0.98 1.13 1.70 1.97 . . .

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.

For each oxygenate, s, calibration data set, obtain the quadratic least-squares fit equation in the following form: r.w.,

=

(b,,)(amt~) + b,(amL) 2

o 1.5 rr O

t)~ r = = 0.99998

FIG. 3

"

I

1

0 An Example

I

I

2 Amount Ratio

of a Quadratic

3

.

.

.

.

.

.

0.08 0.15 0.24 0.39 0.51 0.62 0.73 0.83 1.17 1.33 1.48 1.63 1.90

Total Oxygen ••• 0.13 0.23 0.32 0.41 0.49 ... ... ..• ... .•• •

.

•

( 7 )

11. P r o c e d u r e 11.1 Keep samples refrigerated until ready for analysis. Bring samples to room temperature prior to analysis. 11.2 Tare the sample container and its rubber-faced PTFE-faced sealing cap. Transfer 1 to t0 g of the sample to the container and seal immediately. Weigh the sample container and contents to the nearest 0.1 mg and record the mass of test sample. 11.3 Inject through the rubber membrane a volume of the same internal standard used in generating the standards and reweigh the sample container and contents. Record the difference as the mass of internal standard to the nearest 0.1 mg. The mass of internal standard should be 2 to 6 % of the

t-

0

.

RF,, x = ( R F O ( M W i / M W ~ ) ( N f f N I )

(6)

.5

.

TAME

where: RF,,.,. = relative response factor based on mass of oxygen, RF, = relative mass response factor of the test oxygen compound, as calculated in 10.3 (Eq 3), M W , = molecular mass of the internal standard in the calibration sample, g/mol, MW.~. = molecular mass of the test oxygen compound in the calibration sample as given in Table 2, g/mol, Ns = number of oxygen atoms per molecule of test oxygen compound, and NI = number of oxygen atoms per molecule of internal standard. The relative response factor (mass of oxygen basis) should not deviate from unity by more than _+5 %. Table 2 gives typical relative response factors (on both mass of oxygenates and mass of oxygen basis) for the oxygenates in Fig. 2.

where: rsp~ = response ratio for oxygenate s (y-axis), b,, = linear regression coefficient for oxygenate s, amt, = amount ratio for oxygenate s (x-axis), and bI = quadratic regression coefficient. Figure 3 gives an example of a quadratic least-squares fit for MTBE and the resulting equation in the form of Eq 6: 10.3.2 As a quality assurance check, calculate the relative response factors on a mass % oxygen basis for each oxygen compound according to the following equation:

rr

.

nBA

4

Least-Squares Fit for MTBE

935

qUIl~ D 5599 test sample but not less than 50 mg. 11.4 Ensure that the sample (gasoline plus internal standard) is thoroughly mixed. Transfer an aliquot of the solution to a vial compatible with the autosampler if such equipment is used. Seal the vial with a TFE-fluorocarbonlined septum cap. 11.5 Inject a suitable quantity (0.1 to 1.0 ~tL) of the sample containing internal standard into the chromatograph using the same technique and sample size as used for the calibration standards. The test portion size should be such as not to exceed the capacity of the column or linearity of the detector. 11.6 Acquire peak area and retention time data by way of electronic integrator or computer and, if desired, also by chart recorder. 12. Calculation and Report

12. I Calculate the mass % of each calibrated oxygenate as follows: 12.1.1 After identifying the various oxygenates by retention times, obtain the areas of all calibrated oxygenate peaks and that of the internal standard. Calculate the area response ratio (rsp~) for each of the oxygenates using Eq 4 (10.3. l). 12.1.2 Calculate the amount ratio (amt,) for each calibrated oxygenate in the gasoline sample, by substituting that oxygenate's response ratio (rSPs) and the coefficient of its quadratic calibration curve into Eq 6 (10.3.1) and solving. 12.1.3 Apply Eq 8 to determine the mass % of each calibrated oxygenate. (amt,)( 14/'1)(100 %) w, =

w,

(8)

where:

calibrated oxygenate to mass % oxygen and sum according to the following equation:

O,,n = ]~ [(w~)(16.0)(N~)]

(9)

Ms or [wl][16.0l[Nl]

O,.~n =

[w2][ 16.01[N2]

+

+...

Mt

where: O,.~ = total mass percent oxygen from the calibrated oxygenates, ws = mass % of each oxygenate as determined using Eq 8, N~. = number of oxygen atoms in the oxygenate molecule, M, = molecular mass of the oxygenate as given in Table 2, and 16.0 = atomic mass of oxygen. 12.3.2 Convert the total MTBE-equivalent mass % of uncalibrated oxygenates to mass % oxygen accordings to the following equation: (ws,)(I 6.0)(Ns) 0 ..... i = (11)

Ms.

where: 0,,,,,.~/= total mass % oxygen from the uncalibrated oxygenates, W.,,, = MTBE-equivalent mass % of uncalibrated oxygenates, Ns = number or oxygen atoms in MTBE molecule, M~ = molecular mass of MTBE as given in Table 2, and 16.0 = atomic mass of oxygen. 12.3.3 Calculate the total mass % oxygen in the gasoline sample by summing the contributions from the calibrated components and the uncalibrated components. (12)

0 , , , = O , n + 0 ....... i

w., = mass % of oxygenate in gasoline sample, amt, = amount ratio of oxygenate as determined in 12.1.2, W, = mass of internal standard added to gasoline sample, g, and W~. = mass of gasoline sample, g. 12.1.4 If the mass % of any oxygenate exceeds its calibrated range, gravimetrically dilute a portion of the original sample with oxygenate-free gasoline to a concentration within the calibrated range and analyze the diluted sample in accordance with Section 11 and 12.1. Correct all mass % oxygenate values by multiplying by the dilution factor. 12.2 Calculate the total MTBE-equivalenl mass % of uncalibrated oxygenates as follows: 12.2.1 Sum the peak areas of the uncalibrated oxygenates that are present. Do not include the peak areas due to dissolved oxygen, water, and the internal standard. Calculate the response ratio (rsp.,) for the summed areas of the uncalibrated oxygenates using Eq 4 (10.3.1). 12.2.2 Calculate the amount ratio (amt,) for the uncalibrated oxygenates in the gasoline sample by substituting the response ratio (determined in 12.2.1) and the coefficients of'the MTBE calibration curve into Eq 6 (10.3.1) and solving. 12.2.3 Apply Eq 8 (12.1.3) to determine the total MTBEequivalent mass % of the uncalibrated oxygenates. 12.3 Calculate the total mass % oxygen in the gasoline sample as follows: 12.3.1 Convert the mass % oxygenate of each individual,

( 1O)

M2

12.4 Report the mass % oxygenate of each calibrated oxygenate to the nearest 0.01%. Also report the total mass % oxygen in the gasoline sample to the nearest 0.1%. 13. Quality Control Checks 13.1 Routinely monitor the intralaboratory repeatability and accuracy of the analysis as follows: 13. I. l Intralaboratory Repeatability: 13.1.1.1 Quality control check standards may be prepared from the same oxygenate stocks prepared in 10.2 and covering the range given in 13. I. 1.4. 13.1.1.2 Prepare and analyze duplicates of the quality control check standards at a rate of one per analysis batch or at least one per ten samples, whichever is more frequent. 13.1.1.3 Duplicates should be carried through all sample preparation steps independently. 13.1.1.4 The range (R) for duplicate samples should be less than the following limits: Oxygcnate Methanol Methanol Ethanol MTBE DIPE ETBE TAME

where: 936

Concentration, mass % 0.20 to 1.00 to 1.00 to 0.20 to 1.00 to 1.00 to 1.00 to

L00 12.00 12.00 20.00 20.00 20.00 20.00

Upper Limit lbr Range, mass % 0.010 + 0.043C 0.053C 0.053C 0.069 + 0.029C 0.048C 0.074C 0.060C

( ~ D 5599 14.1.1 Repeatability--The difference between successive results obtained by the same operator with the same apparatus under constant operating conditions on identical test materials would, in the long run and in the normal and correct operation of the test method, exceed the following values only one case in twenty (see Table 3).

C = (C,, + Ca)/2 (13) 1¢ = I C , , - c, iI (14) C,, = concentration of the original sample, and C,/= concentration of the duplicate sample. 13.1.5 If these limits are exceeded, the sources of error in the analysis should be determined, corrected, and all analyses subsequent to and including the last duplicate analysis confirmed to be within the compliance specifications should be repeated. 13.2 lntralaboratory Accuracy." 13.2.1 If the measured concentration of a quality control check standard is outside the range of 100.0 + 6.0 % of the theoretical concentration for a selected oxygenate of 1.0 mass % or above, the sources of error in the analysis should be determined, corrected, and all analyses subsequent to and including the last standard analysis confirmed to be within the compliance specifications should be repeated. 13.2.2 Independent reference standards may be purchased or prepared from materials that are independent of the quality control standards and should not be prepared by the satnc analyst. For the specification limits listed in 13.2.2.2, the concentration of the reference standards should be in the range given in 13.1.1.4. 13.2.2.1 Independent reference standards should be analyzed at a rate of one per analysis batch or at least one per 100 samples, whichever is more frequent. 13.2.2.2 If the measured concentration of an independent reference standard is outside the range of 100.0 +_ 10.0 % of the theoretical concentration for a selected oxygenate of 1.0 mass % or above, the sources of error in the analysis should be determined, corrected, and all analyses subsequent to and including the last independent reference standard analysis confirmed to be within the compliance specifications in that batch should be repeated. 13.3 Control charts may be utilized to monitor the variability of measurements from the quality control check standards and independent reference standards in order to optimally detect abnormal situations and ensure a stable measurement process.

Repeatability for Oxygenates in Gasoline Component Methanol (MeOH) Ethanol (EtOH) lso-propanol (iPA) lerI-Butanol (tBA) n-Propanol (nPA) MTBE st,c-Butanol (sBA) DIPE Iso-butanol (idA) ETBE tert-Pentanol (tAA) n-Butanol (nBA) TAME Total Oxygen

Repeatability 0.07 (X ° 49),4 0.03 (X ° 92) 0.04 (X TM) 0.05 (X ° 65) 0.04 (X °.35) 0.05 (X °.Ss) 0.03 (X TM) 0.05 (X TM) 0.03 (X ° 79) 0.04 (X ° s6) 0.05 (X ° 41) 0.06 (X ° 46) 0.04 (X ° 5~) 0.03 (X ° ~)

a X is the mean mass % of the component.

14.1.2 Reproducibility--The difference between two single and independent results obtained by different operators working in different laboratories on identical material would, in the long run, exceed the following values in only one case in twenty (see Table 3). Reproducibility in Oxygenates in Gasolines Component Methanol (MeOH) Ethanol (EtOH) lso-propanol (iPA) terI-Butanol (tBA) n-Propanol (nPA) MTBE see-Butanol (sBA) DIPE Iso-butanol (idA) ETBE lert-Pentanol (tAA) n-Butanol (nBA) TAME Total Oxygen

14. Precision and Bias 7 14.1 Data obtained from a 10-laboratory round robin on the measurement of 13 oxygenates and total oxygen in 12 gasoline samples were examined. The precision of this test method as determined by a statistical examination of the interlaboratory test results based on 1,2-dimethoxyethane as the internal standard is as follows:

Reproducibility 0.25 (X TM) 0.27 (X °.s°) 0.21 (X °.7 i) 0.20 (X °-s°) 0.17 (X °.ss) O. 10 (X TM) 0.17 (X u,73) 0.16 (X °m) 0.19 (X °.s3) 0.25 (X °.79) 0.18 (X TM) 0.22 (X ° 3o) 0.24 (X ° 69) O. 13 (X TM)

a X is the mean mass % of the component.

14.2 BiasmA statement of bias is currently being developed by the responsible study group. 15. Keywords 15.1 alcohols; DIPE (Di-iso-propylether); ETBE (ethyl tert-butylether); ethanol; gas chromatography; gasoline; methanol; MTBE (methyl tert-butylether); oxygenates; oxygen-selective detection; TAME (tert-amylmethylether)

7 Supporting data are available from ASTM Headquarters. Request RR:D021359.

937

~

D 5599

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned m this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reepproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 100 Barr Harbor Drive, West Conshohocken, PA 19428.

938

~ l ~ ) Designation: D 5622 - 95 Standard Test Methods for Determination of Total Oxygen in Gasoline and Methanol Fuels by Reductive Pyrolysis This standard is issued under the fixed desagnatlon D 5622: the number ~m~nediately following the destgnatlon indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (e) indicates an editorial change since the last revision or reapproval.

1. Scope 1.I These test methods cover the quantitative determination of total oxygen in gasoline and methanol fuels by reductive pyrolysis. 1.2 Precision data are provided for 1.0 to 5.0 mass % oxygen in gasoline and for 40 to 50 mass % oxygen in methanol fuels. 1.3 Several types of instruments can be satisfactory for these test methods. Instruments can differ in the way that the oxygen-containing species is detected and quantitated. However, these test methods are similar in that the fuel is pyrolyzed in a carbon-rich environment. 1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. 1.5 This standard does not purport to address all of the

are pyrolyzed, and the oxygen is quantitatively converted into carbon monoxide. 3.2 A carrier gas, such as nitrogen, helium, or a helium/ hydrogen mixture, sweeps the pyrolysis gases into any of four downstream systems of reactors, scrubbers, separators, and detectors for the determination of the carbon monoxide content, hence of the oxygen in the original fuel sample. The result is reported as mass % oxygen in the fuel.

4. Significance and Use 4.1 These test methods cover the determination of total oxygen in gasoline and methanol fuels, and they complement Test Method D 4815, which covers the determination of several specific oxygen-containing compounds in gasoline. 4.2 The presence of oxygen-containing compounds in gasoline can promote more complete combustion, which reduces carbon monoxide emissions. The Clean Air Act (1992) requires that gasoline sold within certain, specified geographical areas contain a minimum percent of oxygen by mass (presently 2.7 mass %) during certain portions of the year. The requirement can be met by blending compounds such as methyl tertiary butyl ether, ethyl tertiary butyl ether, and ethanol into the gasoline. These test methods cover the quantitative determination of total oxygen which is the regulated parameter.

safety concerns, ~f any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability o.f regulatory limitations prior to use. 2. Referenced Documents 2.1 A S T M Standards." D 1298 Practice for Density, Relative Density (Specific Gravity), or API Gravity of Crude Petroleum and Liquid Petroleum Products by Hydrometer Method 2 D 4052 Test Method for Density and Relative Density of Liquids by Digital Density Meter 3 D4057 Practice for Manual Sampling of Petroleum and Petroleum Products 3 D 4815 Test Method for Determination of MTBE, ETBE, TAME, DIPE, tertiary-Amyl Alcohol and C~ to Ca Alcohols in Gasoline by Gas Chromatography 4 2.2 Other Standard." Clean Air Act (1992) -~

5. Apparatus

5.1 Oxygen Elemental Analyzer6,7.8.9--A variety of instrumentation can be satisfactory. However, the instrument must reductively pyrolize the specimen and convert oxygen to carbon monoxide. 5.1.1 Test Method A6--Helium carrier gas transports the pyrolysis products through a combination scrubber to remove acidic gases and water vapor. The products are then transported to a molecular sieve gas chromatographic column where the carbon monoxide is separated from the other pyrolysis products. A thermal conductivity detector generates a response that is proportional to the amount of carbon monoxide. 5.1.2 Test Method BT--Nitrogen carrier gas transports the pyrolysis products through a scrubber to remove water vapor. The pyrolysis products then flow through tandem

3. Summary of Test Methods 3.1 A fuel specimen of 1 to 10 !aL is injected by syringe into a 950 to 1300"C high-temperature tube furnace that contains metallized carbon. Oxygen-containing compounds

6Carlo Erba Models 1106 and 1108 have been found satisfactory for these analyses. They are available from CE Elantech, Inc., 170 Oberlin Ave. N., Ste 5, Lakewood, NJ 08701. 7 Leco Model RO-478 has been found satisfactory for this analysts. It is avadable from Leco Corp., 3000 Lakeview Ave., St. Joseph. MI 49085. K Perkin-Elmer Series 2400 has been found satisfactory Ibr this analysis It is avadable from Perkin-Elmcr Corp., 761 Mam Ave., Norwalk, CT 06859. '~ UIC. Inc./Coulomemcs Model 5012 CO,,. coulometer and Model 5220 autosampler-furnace have been found satisfactory for this analysts. "l'he~, are available from UIC Inc., Box 863, Joliet. IL 60434.

~These test methods are under the junsdlctton of Committee D-2 on Petroleum Products and Lubricants and are the direct responsibihty of Subcommince D02.03.0A on Chemical Methods, ('urrent edition approved Aug. 15, 1995. Published October 1995. Originally pubhshed as D 5622.- 94 t,as! previous edition D 5622 - 94. , Innttal Bool~ o fASTM Standard~', Vol 05.0 I. hmual Book of ASTM Slandard~'. Vol 05.02. 4 Innual Book o / A S T M Standards, Vol 05.03. Federal Register, Vol 57, No. 24, Feb. 5, 1992, p. 4408.

939

~

D 5622

infrared detectors that measure carbon monoxide and carbon dioxide, respectively. 5.1.3 Test Method C8~A mixture of helium and hydrogen (95:5 %), helium, or argon transports the pyrolysis products through two reactors in series. The first reactor contains heated copper which removes sulfur-containing products. The second reactor contains a scrubber which removes acidic gases and a reactant which oxidizes carbon monoxide to carbon dioxide (optional). The product gases are then homogenized in a mixing chamber, which maintains the reaction products at absolute conditions of temperature, pressure, and volume. The mixing chamber is subsequently depressurized through a column that separates carbon monoxide (or carbon dioxide, if operating, in the oxidation mode) from interfering compounds. A thermal conductivity detector measures a response proportional to the amount of carbon monoxide or carbon dioxide. 5.1.4 Test Method D9~Nitrogen carder gas transports the pyrolysis products through scrubbers to remove acidic gases and water vapor. A reactor containing cupric oxide at 325"C oxidizes the carbon monoxide to carbon dioxide, which in turn is transported into a coulometric carbon dioxide detector. Coulometrically generated base titrates the acid formed by reacting carbon dioxide with monoethanolamine. 5.2 A technique must be established to make a quantitative introduction of the test specimen into the analyzer. Specimen vials and transfer labware must be clean and dry. 5.3 For instruments that measure carbon monoxide only, pyrolysis conditions must be established to quantitatively convert oxygen to carbon monoxide. 5.4 A system of scrubbers and separators must be established to effectively remove pyrolysis products that interfere with the detection of carbon monoxide or carbon dioxide, or both. 5.5 The detector responses must be linear with respect to concentration, or nonlinear responses must be detectable and accurately related to concentration. 5.6 Selected items are available from the instrument manufacturer. 5.6.1 Pyrolysis Tubes, 5.6.2 Scrubber Tubes, and 5.6.3 Absorber Tubes.

6. Reagents 6.1 Purity of Reagents~°~Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society where such specifications are available. Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination. 6.2 Calibration Standards:

6.2.1 NIST SRM 18371 t, which contains certified concentrations of methanol and t-butanol in reference fuel, can be used to calibrate the instrument for the analysis of oxygenates in gasoline. 6.2.2 Anhydrous methanol, 99.8 % minimum assay, can be used to calibrate the instrument for the analysis of methanol fuels. 6.2.3 Isooctane, or other hydrocarbons, can be used as the blank provided the purity is satisfactory. 6.3 Quality Control Standard--NIST SRM 1838 ~t can be used to check the accuracy of the calibration. 6.4 The instrument manufacturers require additional reagents. 6.4.1 Test Method A: 6 6.4.1.1 Anhydrone (anhydrous magnesium perchlorate), 6.4.1.2 Ascarite II (sodium hydroxide on silica), 6.4.1.3 Helium carder gas, 99.995 % pure, 6.4.1.4 Molecular sieve, 5 A, 60 to 80 mesh, 6.4.1.5 Nickel wool, 6.4.1.6 Nickelized carbon, 20 % loading, 6.4.1.7 Quartz chips, and 6.4.1.8 Quartz wool. 6.4.2 Test Method B:7 6.4.2.1 Anhydrone (anhydrous magnesium perchlorate), 6.4.2.2 Carbon pyrolysis pellets, and 6.4.2.3 Nitrogen carder gas, 99.99 % pure. 6.4.3 Test Method C.'8 6.4.3.1 Anhydrone (anhydrous magnesium perchlorate), 6.4.3.2 Ascarite II (sodium hydroxide on silica), 6.4.3.3 Carder gas, either helium (95 %)/hydrogen (5 %), mixture, 99.99 % pure; helium, 99.995 % pure; or argon, 99.98 % pure, 6.4.3.4 Copper plus, wire form, and 6.4.3.5 Platinized carbon. 6.4.4 Test Method 9:9 6.4.4.1 Anhydrone (anhydrous magnesium perchlorate), 6.4.4.2 Ascarite II (sodium hydroxide on silica), 6.4.4.3 Copper (II) oxide, 6.4.4.4 Coulometric cell solutions, including a cathode solution of monoethanolamine in dimethyl sulfoxide and an anode solution of water and potassium iodide in dimethyl sulfoxide, 6.4.4.5 Nickelized carbon, 20 % loading, and 6.4.4.6 Nitrogen carder gas, 99.99 % pure.

7. Sampling 7.1 Take samples in accordance with the instructions in Practice D 4057. 7.2 Visually inspect the samples, and when there is evidence of nonuniformity, take fresh samples. 7.3 Store the samples in a cold room or a laboratory refrigerator designed for storage of chemicals. 8. Preparation of Apparatus 8.1 Prepare the instrument in accordance with the manufacturer's recommendations. These test methods require that correct operating procedures are followed for the model

"~ Reagent Chemicals, Amerwan Chemwal Societ.v Spectficatton.~, American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed by the American Chemical Society, see Analar Standard~" ./or Laboratory C'lwmicals, BDH Ltd., Poolc, Dorset, U.K., and the United States Pharmacopeta and National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville, MD.

~J Available from the National Institute of Standards and Technology, Gaithersburg, MD 20899.

940

~

D 5622 10. Calculation and Report

used. Instrument design differences make it impractical to specify all of the required operating conditions. 8.2 The carrier gas can be scrubbed to remove traces of oxygen and oxygen-containing compounds.

10.1 Calculate the mass % oxygen for the QC standard and samples as follows:

RxK

Mass % Oxygen = M x r

where: R = blank corrected instrument response, K = K-factor, refer to Eq l, assume unity for Test Method D, M = mass of sample, mg, = volume (IxL) x density (g/mL), and r = recovery, refer to 9.4.3, assume unity for Test Methods A, B, and C. 10.2 For instruments with computer data systems, the calculation of the K-factor (Eq l) and the calculation of mass % oxygen (Eq 2) can be automatic with a digital readout provided. 10.3 Report mass % oxygen to the nearest 0.01%.

9. Calibration and Standardization

9.1 Calibration for Test Methods A, B, and C, Oxygenates in Gasoline: 9.1.1 Use a syringe to introduce 1 to 10 IxL, or 1 to 10 mg, of the blank. The amount of specimen must be precisely known. Measure the response. Repeat the introduction and measurement until stable readings are observed. 9.1.2 In similar fashion, introduce 1 to 10 lxL, or 1 to 10 mg, of SRM 1837 and measure the response. Repeat two times with the same quantity of the SRM. If the blank corrected responses do not agree within 2 % relative, take corrective action and repeat the calibration. 9.1.3 Calculate the K-factor as follows: K--

Cstd X Mst d

(2)

11. Precision and Bias 12

(1)

I I. l Precision--The precision of these test methods was determined by statistical analysis of interlaboratory test results. Twelve laboratories analyzed in duplicate eight different samples, providing a total of thirteen data sets. One laboratory used two different test methods. The breakdown on data sets by test method is: Test Method A, three; Test Method B, two; Test Method C, three; Test Method D, five. The statistical analysis was performed on the set of 13 data sets because the reductive pyrolysis technique is common to all four test methods. Separate statistics were not determined for individual test methods. The sample set included anhydrous methanol and gasoline stocks that were spiked with one or more of the following: isobutanol, n-butanol, secbutanol, tert-butanol, di-isopropyl ether, ethanol, ethyl leftbutyl ether, methanol, methyl tert-butyl ether, n-propanol, isopropanol, tert-amyl methyl ether. 1 l . l . l Repeatability--The difference between two test results, obtained by the same operator with the same apparatus under constant operating conditions on identical test materials would, in the long run, in the normal and correct operation of the test method, exceed the following values in only one case in twenty.

Ravg

where: mass % oxygen in the SRM, mass of the SRM, mg, volume of the SRM (~tL) × density of the SRM (g/mL), and Ravg --- average of the blank corrected responses. NOTE l--Density can be determinedby Test Method D 1298 or Test Method D 4052. Cstd Mst d =

9.2 Cafibration for Test Methods A, B, and C, Methanol Fuels--Repeat procedure 9.1; however, substitute anhydrous methanol for the SRM. For methanol fuels, a unique K-factor can be necessary. 9.3 Calibration for Test Method D--This test method does not require calibration; however, a quality control standard must be analyzed to ensure proper operation of the instrument. A blank must also be analyzed periodically to ensure consistent responses. 9.4 Quality Control (QC): 9.4.1 Introduce the QC standard SRM 1838 in the same manner as the calibration standards. Calculate the percent oxygen (m/m) as described in Section 10. 9.4.2 When results obtained on the QC standard do not agree with the certified values within 2 % relative, take corrective action and repeat the calibration and quality control. 9.4.3 For Test Method D, when the recovery of oxygen from the QC SRM is less than 0.85 (that is, 85 %), take corrective action and repeat the quality control. Recoveries that are greater than 0.85 but less than unity can be used to correct the calculated result (refer to the r parameter in Section 10). 9.5 Procedure: 9.5.1 Introduce the samples, and record the instrument response. Calculate the results as described in Section 10. Use the appropriate K-factor for oxygenates in gasoline and methanol fuels. 9.5.2 Recalibrate the instrument with the appropriate calibration standard after each set of ten samples.

Mass % Oxygen Range

Repeatability, Mass % Oxygen

1.0 to 5.0 % 40 to 50 %

0.06 % 0.81%

1 I. 1.2 Reproducibility--The difference between two single and independent results, obtained by different operators working in different laboratories on identical test materials, would in the long run, in the normal and correct operation of the test method, exceed the following values in only one case in twenty. Mass % Oxygen Range

Reproducibility, Mass % Oxygen

1.0 to 5.0 % 40 to 50 %

0.26 % 0.81%

11.2 Bias--Bias was determined from interlaboratory results obtained on NIST SRM 1838, which contains ,2 Interlaboratory study data are available from ASTM by requesting RR:D021338.

941

~

D 5622 12. Keywords

ethanol. The null hypothesis that was tested was that the true difference between the grand average result and the NIST certified value is zero. The result of the hypothesis testing was that if the true difference was zero, the determined difference would occur by chance approximately 50 % of the time. Hence, the null hypothesis of no difference or no bias is accepted.

12.1 carbon dioxide; carbon monoxide; di-isopropyl ether; ethanol; ethyl tert-butyl ether; isobutanol; isopropanol; methanol; methyl tert-butyl ether; n-butanol; n-propanol; oxygen; reductive pyrolysis; see-butanol; tert-butanol; tertamyl methyl ether

APPENDIX

(Nonmandatory Information) XI. EFFECT OF WATER IN GASOLINE CONTAINING OXYGENATES anol, di-isopropyl ether, n-propanol. A few millilitres of each water-spiked gasoline were treated with 200 mg of potassium carbonate prior to analysis. The results obtained on the treated, spiked samples did not differ from the results obtained on the neat gasolines by more than 0.02 mass % oxygen, which is within the repeatability of these test methods. X I.3 The literature ~4 describes an alternative technique for removing water from gasoline, namely, treatment of the gasoline with Molecular Sieve 3A. In an experiment similar to that described in X 1.2, water-spiked, oxygenated gasolines were pretreated with Sieve 3A prior to analysis by Test Method B. The results obtained on the sieve treated, spiked samples did not differ from the results obtained on the neat gasolines by more than the repeatability of these test methods.

X I.1 The Clean Air Act (1992) requirement for oxygenates in gasoline implicitly excludes water-borne oxygen from the specification for total oxygen. Experimental evidence indicates that for typical oxygenated gasolines, the maximum amount of soluble water is approximately 0.1 mass %. This corresponds to 0.09 mass % oxygen which is very close to the repeatability of these test methods. When oxygen from dissolved water must be excluded from the analysis, the gasoline can be pretreated with potassium carbonate or Molecular Sieve 3A prior to analysis by these test methods. X 1.2 According to the patent literature 13, gasoline can be treated with potassium carbonate to remove dissolved water. Test Method B was used to analyze five different gasolines that were spiked with 0.1 mass % water. These gasolines contained one or more of the following oxygenates at concentrations typical of gasolines: tert-amyl methyl ether, ethanol, ethyl tert-butyl ether, see-butanol, n-butanol, meth-

14 Burfield, D. R., and Smithers, R, H., "Desiccant Efficiency in Solvent and Reagent Drying," Journal of Organic Chemistry, Vol 48, No. 14, 1983, pp. 2420-2422.

~3 U.S. Patent No. 4 539 013, Sep. 3, 1985.

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to rewsion at any time by the responsible technical committee and must be reviewed every five years and ff not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, whtch you may attend. If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St, Philadelphia, PA 19103.

942

(~l~

Designation: D 5623 - 94

Standard Test Method for Sulfur Compounds in Light Petroleum Liquids by Gas Chromatography and Sulfur Selective Detection 1 This standard is issued under the fixed designation D 5623; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last rcapproval. A superscript epsilon (e) indicates an editorial change since the last revision or reapproval.

1. Scope 1.1 This test method covers the determination of volatile sulfur-containing compounds in light petroleum liquids. This test method is applicable to distillates, gasoline motor fuels (including those containing oxygenates) and other petroleum liquids with a final boiling point of approximately 230"C (450"F) or lower at atmospheric pressure. The applicable concentration range will vary to some extent depending on the nature of the sample and the instrumentation used; however, in most cases, the test method is applicable to the determination of individual sulfur species at levels of 0.1 to 100 mg/kg. 1.2 The test method does not purport to identify all individual sulfur components. Detector response to sulfur is linear and essentially equimolar for all sulfur compounds within the scope (1.1) of this test method; thus both unidentified and known individual compounds are determined. However, many sulfur compounds, for example, hydrogen sulfide and mercaptans, are reactive and their concentration in samples may change during sampling and analysis. Coincidently, the total sulfur content of samples is estimated from the sum of the individual compounds determined; however, this test method is not the preferred method for determination of total sulfur. 1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

2. Referenced Documents 2.1 ASTM Standards: D2622 Test Method for Sulfur in Petroleum Products (X-Ray Spectrographic Method) 2 D 3120 Test Method for Trace Quantities of Sulfur in Light Liquid Petroleum Hydrocarbons by Oxidative Microcoulometry2 D4057 Practice for Manual Sampling of Petroleum and Petroleum Products2 J This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.04.0L on Gas Chromatography. Current edition approved Dec. 15, 1994. Published February 1995. 2 Annual Book of ASTM Standards, Vol 05.02.

D 4307 Practice for Preparation of Liquid Blends for Use as Analytical Standards 2 D 4626 Practice for Calculation of Gas Chromatographic Response Factors 2

3. Summary of Test Method 3.1 The sample is analyzed by gas chromatography with an appropriate sulfur selective detector. Calibration is achieved by the use of an appropriate internal or external standard. All sulfur compounds are assumed to produce equivalent response as sulfur. 3.2 Sulfur Detection--As sulfur compounds elute from the gas chromatographic column they are quantified by a sulfur selective detector that produces a linear and equimolar response to sulfur compounds; for example sulfur chemiluminescence detector or atomic emission detector (AED 3) used in the sulfur channel. 4. Significance and Use 4.1 Gas chromatography with sulfur selective detection provides a rapid means to identify and quantify sulfur compounds in various petroleum feeds and products. Often these materials contain varying amounts and types of sulfur compounds. Many sulfur compounds are odorous, corrosive to equipment, and inhibit or destroy catalysts employed in downstream processing. The ability to speciate sulfur compounds in various petroleum liquids is useful in controlling sulfur compounds in finished products and is frequently more important than knowledge of the total sulfur content alone. 5. Apparatus 5.1 Chromatograph--Use a gas chromatograph (GC) that has the following performance characteristics: 5.1.1 Column Temperature Programmer--The chromatograph must be capable of linear programmed temperature operation over a range sufficient for separation of the components of interest. The programming rate must be sufficiently reproducible to obtain retention time repeatability of 0.05 rain (3 s) throughout the scope of this analysis. 5.1.2 Sample Inlet System--The sample inlet system must have variable temperature control capable of operating continuously at a temperature up to the maximum column temperature employed. The sample inlet system must allow a constant volume of liquid sample to be injected by means of a syringe or liquid sampling valve. 3 The AED is manufactured by Hewlett-Packard Co., 2850 Centerville Rd., Wilmington, DE 19808-1610.

943

o ssaa 5.1.3 Carrier and Detector Gas Control--Constant flow control of carder and detector gases is critical to optimum and consistent analytical performance. Control is best provided by the use of pressure regulators and fixed flow restrictors or mass flow controllers capable of maintaining gas flow constant to _ 1% at the required flow rates. The gas flow rate is measured by any appropriate means. The supply pressure of the gas delivered to the gas chromatograph must be at least 70 kPa (10 psig) greater than the regulated gas at the instrument to compensate for the system back pressure of the flow controllers. In general, a supply pressure of 550 kPa (80 psig) is satisfactory. 5.1.4 Cryogenic Column Cooling--An initial column starting temperature below ambient temperature may be required to provide complete separation of all of the sulfur gases when present in the sample. This is typically provided by adding a source of either liquid carbon dioxide or liquid nitrogen, controlled through the oven temperature circuitry. 5.1.5 Detector--A sulfur selective detector is used and shall meet or exceed the following specifications: (a) linearity of 104, (b) 5 pg sulfur/s minimum detectability, (c) approximate equimolar response on a sulfur basis, (d) no interference or quenching from co-eluting hydrocarbons at the GC sampling volumes used. 5.2 Column--Any column providing adequate resolution of the components of interest may be used. Using the column and typical operating conditions as specified in 5.2.1, the retention times of some sulfur compounds will be those shown in Table 1. The column must demonstrate a sufficiently low liquid phase bleed at high temperature, such that loss of the detector response is not encountered while operating at the highest temperature required for the analysis. 5.2.1 Typical Operating Conditions: 5.2.1.1 Column--30 m by 0.32 mm inside diameter fused TABLE 1

Sulfur Compounds

Retention Time (rain) 0.95 1.21 1.34 3.43 7.20 7.76 8.24 8.92 10.04 10.42 10.53 12.01 12.04 12.18 12.82 13.33 13.90 14.71 14.84 17.89 24.55 24.66 24.77 24.88 28.64

6. Reagents and Materials 6.1 Purity of Reagents--Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society where such specifications are available. 4 Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination. 6.1.1 Alkane SolventmSueh as, iso-octane (2,2,4-trimethylpcntane), Reagent grade, for use as solvent (diluent) in preparation of system test mixtures and for preparation of internal standard stock solution (Warning--See Note 1). NOTE h Warning--Iso-octane is flammable and can be harmful when ingested or inhaled.

Typical Retention Times for Common Sulfur Compounds ~

Hydrogen Sulfide Carbonyl Sulfide Sulfur Dioxide Methanethiol Ethanethiol Dimethyl Sulfide Carbon Disulfide 2-Propanethlol 2-methyl-2-propanethlol 1-Propanethlol Ethylmethyl sulfide 2-Butanethiol Thiophene 2-methyl-l-propanethiol Diethyl Sulfide 1-Butanethiol Dimethyl Disulfide 2-Methylthiophene 3-Methylthiophene Diethyl Disulfide Methylbenzothiophene Methylbenzothiophene Methylbenzothiophene Methylbenzothiophene Diphenyl sulfide

silica wall coated open tube (WCOT) column, 4-~tm thick film of methylsilicone. 5.2.1.2 Sample size--O. 1 to 2.0-1xL. 5.2.1.3 Injector--Temperature 275"C; Split ratio: 10:I (10 % to column). 5.2.1.4 Column Oven--lO*C for 3 min, 10*C/min to 250"C, hold as required. 5.2.1.5 Carrier Gas--Helium, Head pressure: 70 to 86 kPa (10 to 13 psig). 5.2.1.6 Detector--Sulfur chemiluminescence detector. 5.3 Data Acquisition: 5.3.1 RecordermThe use of a 0 to 1 mV recording potentiometer, or equivalent, with a full-scale response time of 2 s, or less, is suitable to monitor detector signal. 5.3.2 Integrator--The use of an electronic integrating device or computer is recommended for determining the detector response. The device and software must have the following capabilities: (a) graphic presentation of the chromatogram, (b) digital display of chromatographic peak areas, (c) identification of peaks by retention time or relative retention time, or both, (d) calculation and use of response factors, (e) internal standardization, external standardization, and data presentation.

6.1.2 Aromatic Solvent--Such as, toluene, Reagent grade, for use as solvent (diluent) in preparation of system test mixtures (Warning--See Note 2). NOTE 2: Warning--Reagent grade toluene is flammable and is toxic by inhalation, ingestion, and absorption through skin.

6.1.3 Carrier Gas--Helium or nitrogen of high purity (Warning--See Note 3). Additional purification is recommended by the use of molecular sieves or other suitable agents to remove water, oxygen, and hydrocarbons. Available pressure must be sufficient to ensure a constant carrier gas flow rate (see 5.1.3). NOTE 3: WarningnHelium and nitrogen are compressed gases under high pressure.

6.1.4 Detector Gases--Hydrogen, nitrogen, air, and ox4 Reagent Chemicals, American Chemical Society Specifications, American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed by the American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Peele, Dorset, U.K., and the United States Pharmacopeia and National Formulary, U.S. Pharmaceutical Convention, inc. (USPC), Rockville, MD.

A Conditions specified in 5.2.1.

944

~

D 5623 detector operating conditions are shown in 5.2.1. 7.2 Detector--Place in service in accordance with the manufacturer's instructions. After sufficient equilibration time (for example, 5 to 10 min), adjust the detector output signal or integrator input signal to approximately zero. Monitor the signal for several minutes to verify compliance with the specified signal noise and drift. 7.3 System Performance Specification--The inlet system should be evaluated for compatibility with trace quantities of reactive sulfur compounds. Inject and analyze a suitable amount (for example, 0.1 to 2.0-~tL) of the system test mixture (6.1.8). All sulfur compounds should give essentially equimolar response and should exhibit symmetrical peak shapes. Relative response factors should be calculated for each sulfur compound in the test mixture (relative to a referenced component) in accordance with Practice D 4626 or Eq. 1:

ygen may be required as detector gases. These gases must be free of interferring contaminants, especially sulfur compounds. (Warning--See Note 4). Note 4: Warning--Hydrogenis an extremelyflammablegas under high pressure. Warning--Compressedair and oxygenare gases under high pressure and they support combustion. 6.1.5 External Standards--The sulfur compounds and matrices of external standards should be representative of the sulfur compounds and sample matrices being analyzed. Test Methods D2622 and D3120 can be used to analyze materials for calibration of this test method. The internal standardization procedure can also be used for generating external standards. Alternatively, primary standards prepared as described in 6.1.4 can be used for method calibration when it is demonstrated that the matrix does not affect calibration. Only one external standard is necessary for calibration, provided that the system performance specification (7.3) is met. An external standard must contain at least one sulfur compound at a concentration level similar, for example, within an order of magnitude to those in samples to be analyzed. 6.1.6 Internal Standards--Diphenyl sulfide, 3-chlorothiophene, and 2-bromothiophene are examples of sulfur compounds that have been used successfully as internal standards for samples within the scope of this test method (Warning--See Note 5). Any sulfur compound is suitable for use as an internal standard provided that it is not originally present in the sample, and is resolved from other sulfur compounds in the sample. Use the highest purity available (99 + % when possible). When purity is unknown or questionable, analyze the material by any appropriate means and use the result to provide accurate internal standard quantities. 6.1.6.1 An internal standard stock solution should be made up in the range of 0.1 to 1 g of the internal standard on a sulfur basis to 1 kg of solvent. 6.1.7 Sulfur Compound Standards--99 + % purity (if available). Obtain pure standard material of all sulfur compounds of interest (Warning--See Note 5). If purity is unknown or questionable, analyze the individual standard material by any appropriate means and use the result to provide accurate standard quantities.

Rr.

C. x A. Cr x A.

(l)

= ~

where: Rr. = relative response factor for a given sulfur compound, C. --- concentration of the sulfur compound as sulfur, A~ = peak area of the sulfur compound, Cr = concentration of referenced sulfur standard as sulfur, and Ar = peak area of the referenced sulfur standard. The relative response factor (R~.) for each sulfur compound should not deviate from unity by more than +10 %. Deviation of response by more than __.10% or severe peak asymmetry indicates a chromatography or detector problem that must be corrected to ensure proper selectivity, sensitivity, linearity, and integrity of the system. If necessary, optimize the system according to instructions from the manufacturers.

NOTE 5: Warning~Sulfur compounds can be flammable and harmfulor fatal wheningestedor inhaled. 6.1.8 System Test Mixture--Gravimetrically prepare a stock solution of sulfur compounds in accordance with Practice D 4307. This solution should cover the volatility range encountered in samples of interest; for example, dimethyl sulfide (~0.1 g/kg), 2-propanethiol (~0.1 g/kg), dimethyl disulfide (~10 g/kg), 3-methylthiophene (~100 g/kg), and (~10 g/kg) benzothiophene. Prepare a working test mix solution by making a 1000:1 dilution of the stock solution in a mixture of 10 % toluene in iso-octane. Although 2-propanethiol is not stable in the long term, peak asymmetry of a thiol (mercaptan) is an indicator of GC system activity.

8. Sampling 8.1 Appropriate sampling procedures are to be followed. This test method is not suitable for liquified petroleum gases. Volatile liquids to be analyzed by this test method shall be sampled using the procedures outlined in Practicc D 4057. A sufficient quantity of sample should be taken for multiple analyses to be performed (at least 10 to 20 g for quantitation by internal standardization). Store all samples and standard blends at a temperature of 7 to 15°C (45 to 60"F). Do not open the sample or standard container at temperatures above 15"C (60"F). 9. Procedure 9.1 A list of typical apparatus and conditions is provided in 5.2.1. Table 2 provides a listing of the retention times for common sulfur compounds that are typical for the column and conditions specified in 5.2.1. Whenever possible, the retention times of sulfur compounds of interest should be TABLE 2

Sulfur Chemiluminescence Detection and Internal

Standardization Concentration, mg/kg S

7. Preparation of Apparatus 7.1 Chromatograph--Place in service in accordance with the manufacturer's instructions. Typical chromatograph and

Single stable component Total sulfur

945

1 to 100 10 to 200

Repeatability, mg/kg S 0.11 x Concentration 0.12 x Concentration

o s623 determined experimentally. Figure 1 shows a chromatogram from a typical analysis. 9.2 Sample Preparation for Analysis by lnternal Standardization--Add a quantity of suitable internal standard dissolved in iso-octane or another suitable solvent (internal standard stock solution, 6.1.6.1), to an accurately measured quantity of sample on a gravimetric (mass) basis. The final concentration of the internal standard in the sample aliquot, on a sulfur basis, should be approximately one half of the concentration range of sulfur compounds in the original sample. A concentration of approximately 1 to 50 mg/kg of internal standard on a sulfur basis has been used successfully for most samples. 9.3 Sample Analysis by External Standardization--At least once a day, or as frequently as deemed expedient, use the external standard(s) (6.1.5) to calibrate the instrument. The volume of external standard injected for calibration must be exactly the same as the sample volume injected for analysis. 9.4 Chromatographic Analysis--Introduce a representative aliquot of sample into the gas chromatograph. For internal standardization, the sample aliquot must contain a measured quantity of internal standard (6.1.6). Exercise care that the amount of sample and standard injected does not cause detector saturation (indicated by flat-topped peaks). Typical sample size ranges from 0.1 to 2.0-gL. Obtain the chromatographic data by way of a potentiometric recorder (graphic), digital integrator, or computer based chromatographic data system. Examine the graphic display or digital data for any errors. 10. Calculations

10.1 Mass Concentration of Sulfur Compounds as Sulfur-After identifying the sulfur compounds of interest by retention time, measure the area of each sulfur peak. 10.1.1 Sulfur Concentration by Internal Standardization-Compare the area response of each sulfur compound of interest to that of the internal standard. Calculate the concentration of each sulfur peak according to Eq. 2:

C. =

C, x W, x A . (2)

Wsx X A i

where: C, -- concentration (mg/kg) of sulfur compound as sulfur, C~ = concentration (mg/kg) of internal standard in stock solution calculated as sulfur, IV,. = mass of internal standard stock solution added to the sample, A, = peak area of the sulfur compound, W,x = mass of sample aliquot, and A~ = peak area of the internal standard. 10.1.2 Sulfur Concentration by External Standardizat i o n - A n appropriate external standard (6.1.5) is chosen for calibration. The sulfur compound(s) and matrix of the external standard chosen should be representative of the sample(s) being analyzed. Compare the area response of each

sulfur compound of interest to that of the external standard. Calibrate the concentration of each sulfur peak according to Eq. 3: c. =

Ce × De × A n Dsx × A e

(3)

where: 6", -- concentration (mg/kg) of sulfur compound as sulfur, Ce = concentration (mg/kg) of external standard calculated as sulfur, De -- density of external standard matrix, A, -- peak area of the sulfur compound, D= -- density of sample matrix, and A e = peak area of the external standard. This equation assumes that equivalent volumes of sample and standard are injected. 10.2 Report the concentration of each sulfur compound as sulfur in units of mg/kg (ppm wt) to the appropriate number of significant figures. 10.3 Mass Concentration of Total Sulfur in Sample--Sum the sulfur content of all sulfur components (knowns and unknowns) in the sample to arrive at its total sulfur value according to Eq. 4: Cs, o, = Z c . (4) where: Cs~ol = concentration of total sulfur in the sample. 10.4 Report the concentration of total sulfur in units of mg/kg to the appropriate number of significant figures. 10.5 Mass Concentration of Sulfur Compounds as Compound-In 9.1 the concentration of sulfur compounds is reported on a sulfur basis. In some instances the concentration of sulfur compounds as compound is of interest. This conversion is made according to Eq. 5:

CnxM S x 32.07

cw = -

(5)

where: Cw --concentration of the sulfur compound as compound, 6", -- concentration of sulfur compound as sulfur, M = Molar mass of the compound in g/mol, S -- number ofsulfur atoms in the molecular formula of the compound, and, 32.07 = the mass of one tool of sulfur, g. 11. Precision and Bias s

11.1 Data is insufficient for determining precision and bias of AED use in this test method. Data is sufficient, however, for determining precision of sulfur chemiluminescence detector used in this test method. The precision of this test method as determined by the statistical examination of the interlaboratory test results is as follows: s Supporting data are available from ASTM Headquarters. Request RR:D021335.

946

~

D 5623 17

12. C2-thiophenes 1. Ethanethiol 13. Diethyl disulfide 2. Dimethyl sulfide 14. Benzothiophene 3. Carbon disulfide 15. Cl-benzothiophenes 4. 2-Propanethiol 16, C2-benzothiophenes 5. 2-Methyl-2-propanethiol 17, Diphenyl sulfide (Int Std) 6. 1-Propanethlol 7. Ethylmethyl sulfide 8. Thlophene/2-Methyl-l-propanethiol 9. DImethyl Disulfide 10. 2-Methylthiophene 11.3-Methylthlophene ,,

14

15

ul

8 i

12 ~

1

0

I 16

4 5 67 I

0.0

I

I

I

I

I

4.0

I

8.0

I

I

16.0 20.0 12.0 Time (minutes)

24.0

28.0

NOTE--Conditionsas shown in 5.2.1, column: 30 m, 0.32 mm inside diameter, 4 I~m methyl silicone wall coated open tube fused silica; temperature program: -10"C for 3 rain to the final required temperature at a rate of 10°C/rain. FIG. 1 Chromatogram from the analysis of • typical gasoline sample containing approximately 85 ppm wt total sulfur. TABLE 3

Sulfur Chemiluminescence Detection and External Standardization

Single stable component Total sulfur TABLE 4

Concentration, mg/kg S

Repeatability, mg/kg S

1 to 100 10 to 200

0.31 x Concentration 0.24 x Concentration

Sulfur Chemiluminescence Detection and Internal

Standardization

Single stable component Total sulfur

Concentration, mg/kg S

Reproducibility, mg/kg S

1 to 100 10 to 200

0.42 x Concentration 0.33 x Concentration

TABLE 5 Sulfur ChemiluminescenceDetection and External Standardization Concentration, mg/kg S Reproducibility, mg/kgS Singlestablecomponent Total sulfur

1 to 100 10 to 200

11.1.1 RepeatabilitymThe difference between successive test results obtained by the same operator with the same apparatus under constant operating conditions on identical test material would, in the long run, in the normal and correct operation of the test method, exceed the following values only in one case in twenty (see Tables 2 and 3). 11.1.2 ReproducibilitymThe difference between two single and independent results obtained by different operators working in different laboratories on identical test material would, in the long run, exceed the following values only in one case in twenty (see Tables 4 and 5). 11.2 Bias--Since there is no accepted reference material suitable for measuring bias for this test method, no statement of bias can be made. 12. Keywords 12.1 atomic emission detection; gas chromatography; sulfur chemiluminescence detection; sulfur compounds

0.53 x Concentration 0.52 x Concentration

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reepproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103.

947

(~l~ Designation: D 5708 - 95a Standard Test Methods for Determination of Nickel, Vanadium, and Iron in Crude Oils and Residual Fuels by Inductively Coupled Plasma (ICP) Atomic Emission Spectrometry I This standard is issued under the fixed designation D 5708; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (~) indicates an editorial change since the last revision or reapproval.

D 5185 Test Method for the Determination of Additive Elements, Wear Metals, and Contaminants in Used Lubricating Oils by Inductively Coupled Plasma Atomic Emission Spectrometry5

1. Scope 1.1 These test methods cover the determination of nickel, vanadium, and iron in crude oils and residual fuels by inductively coupled plasma (ICP) atomic emission spectrometry. Two different test methods are presented. 1.2 Test Method A (Sections 7 to 11 and 18 to 21)--ICP is used to analyze a sample dissolved in an organic solvent. This test method uses oil-soluble metals for calibration and does not purport to quantitatively determine or detect insoluble particulates. 1.3 Test Method B (Sections 12 to 21)--ICP is used to analyze a sample that is decomposed with acid. 1.4 The concentration ranges covered by these test methods are determined by the sensitivity of the instruments, the amount of sample taken for analysis, and the dilution volume. A specific statement is given in Note 4. Typically, the low concentration limits are a few tenths of a mg/kg. Precision data are provided for the concentration ranges specified in Section 20. 1.5 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. 1.6 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system are not exact equivalents; therefore, each system shall be used independently of the other. 1.7 This standard does not purport to address all of the

3. Summary of Test Methods 3.1 Test Method A--Approximately 10 g of the sample are dissolved in an organic solvent (Warning--see Note 1) to give a specimen solution containing 10 % (m/m) of sample. The solution is nebulized into the plasma, and the intensities of the emitted light at wavelengths characteristic of the analytes are measured sequentially or simultaneously. The intensities are related to concentrations by the appropriate use of calibration data. NOTE 1: W a r n i n g - - C o m b u s t i b l e . Vapor is harmful.

3.2 Test Method B--One to 20 g of sample are weighed into a beaker and decomposed with concentrated sulfuric acid (Warningmsee Note 2) by heating to dryness. Great care must be used in this decomposition because the acid fumes are corrosive and the mixture is potentially flammable. The residual carbon is burned offby heating at 525"C in a muffle furnace. The inorganic residue is digested with nitric acid (Warning--see Note 2), evaporated to incipient dryness, dissolved in dilute nitric acid, and made up to volume. The solution is nebulized into the plasma of an atomic emission spectrometer. The intensities of light emitted at characteristic wavelengths of the metals are measured sequentially or simultaneously. These intensities are related to concentrations by the appropriate use of calibration data.

safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

NOTE 2: W a r n i n g - - P o i s o n . Causes severe burns. Harmful or fatal if swallowed or inhaled.

. Referenced Documents

4. Significance and Use 4.1 These test methods cover, in single procedures, the determination of Ni, V, and Fe in crude oils and residual oils. These test methods complement Test Method D 1548, which covers only the determination of vanadium. 4.2 When fuels are combusted, vanadium present in the fuel can form corrosive compounds. The value of crude oils can be determined, in part, by the concentrations of nickel, vanadium, and iron. Nickel and vanadium, present at trace levels in petroleum fractions, can deactivate catalysts during processing. These test methods provide a means of determining the concentrations of nickel, vanadium, and iron.

2.1 A S T M Standards: D 1193 Specification for Reagent Water2 D 1548 Test Method for Vanadium in Navy Special Fuel Oil 3 D4057 Practice for Manual Sampling of Petroleum and Petroleum Products4 This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.03.0B on Spectrometric Methods. Current edition approved Oct. 10, 1995. Published December 1995. Originally published as D 5708 - 95. Last previous edition D 5708 - 95. 2 Annual Book of ASTM Standards, Vol I 1.01. 3 Annual Book of ASTM Standards, Vol 05.01. 4 Annual Book of ASTM Standards, Vol 05.02.

s Annual Book of ASTM Standards, Vol 05.03.

948

v sz0a TABLE 1 Elements Determined and Suggested Wavelengths NOTE-- These wavelengths are suggestions and do not represent all possible choices. A

5. Purity of Reagents 5.1 Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society where such specifications are available. 6 Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination. 5.2 When determining metals at concentrations less than 1 mg/kg, use ultra-pure reagents. 5.3 Purity of Water--Unless otherwise indicated, reference to water shall be understood to mean reagent water conforming to Type II of Specification D 1193.

Element

Wavelength, nm

Iron

259.94, 238.20 231.60, 216.56 292.40, 310.22

Nickel Vanadium

A Winge, R. K., Fassel, V. A., Peterson, V. J., and Floyd, M. A., Inductively Coupled Plasma Atomic Emission Spectroscopy: An Atlas of Spectral Information, Elsevier, NY, 1985.

contains low concentrations (typically, a few mg/kg) of the analytes. 8.2 Mineral Oil--A high-purity oil such as U.S.P. white oil. 8.30rganometallic Standards--Pre-prepared multi-element concentrates containing 100 mg/kg concentrations of each element are satisfactory)

6. Sampling and Sample Handling 6.1 The objective of sampling is to obtain a sample for testing purposes that is representative of the entire quantity. Thus, take samples in accordance with the instructions in Practice D 4057. Do not fill the sample container more than two-thirds full. 6.2 Prior to weighing, stir the sample and manually shake the sample container. If the sample does not readily flow at room temperature, heat the sample in a drying oven at 80"C or at another safe temperature. TEST METHOD A-ICP WITH AN ORGANIC SOLVENT SPECIMEN SOLUTION

7. Apparatus

7.1 Inductively Coupled Plasma Atomic Emission Spectrometer-Either a sequential or simultaneous spectrometer, equipped with a quartz torch and radio-frequency generator to form and sustain the plasma, is suitable. 7.2 NebufizerBThe use of a high-solids nebulizer is optional but strongly recommended. This type of nebulizer minimizes the probability of clogging. A concentric glass nebulizer can also be used. 7.3 Peristaltic Pump--This pump is required for nonaspirating nebulizers and optional for aspirating nebulizers. The pump must achieve a flow rate in the range of 0.5 to 3 mL/min. The pump tubing must be able to withstand at least a 6 h exposure to the solvent. Fluoroelastomer copolymer tubing is recommended. 7 7.4 Specimen Solution Containers, glass or plastic vials or bottles with screw caps and a capacity of between 50 to 100 mL. One hundred millilitre glass bottles are satisfactory.

9. Preparation of Standards and Specimens 9.1 Blank--Prepare a blank by diluting mineral oil with dilution solvent. The concentration of mineral oil must be 10 % (m/m). Mix well. 9.2 Check StandardBUsing organometallic standards, mineral oil, and dilution solvent, prepare a check standard to contain analyte concentrations approximately the same as expected in the specimens. The concentration of oil in the check standard must be 10 % (m/m). 9.3 Test Specimen~Weigh a portion of well-mixed sample into a container and add sufficient solvent to achieve a sample concentration of 10 % (m/m). Mix well. 9.4 Working Standard--Prepare an instrument calibration standard that contains 10 mg/kg each of vanadium, nickel, and iron. Combine the organometallic standard, dilution solvent and, if necessary, mineral oil so that the oil content of the calibration standard is 10 % (m/m). 10. Preparation of Apparatus 10.1 Consult the manufacturer's instructions for the operation of the ICP instrument. This test method assumes that good operating procedures are followed. Design differences between instruments make it impractial to specify required parameters. 10.2 Assign the appropriate operating parameters to the instrument taskfile so that the desired analytes can be determined. Parameters include: (1) element, (2) analytical wavelength, (3) background correction wavelengths (optional), (4) interelement correction factors (refer to 10.3), (5) integration time of 1 to 10 s, (6) two to five consecutive repeat integrations. Suggested wavelengths are listed in Table 1. 10.3 Spectral InterferencesBCheck all spectral interferences expected for the analytes. If interference corrections are necessary, follow the manufacturer's operating guide to develop and apply correction factors. 10.3.1 Spectral interferences can usually be avoided by judicious choice of analytical wavelengths. If spectral inter-

8. Reagents 8.1 Dilution Solvent~Mixed xylenes, o-xylene, tetralin and mixed paraffin-aromatic solvents are satisfactory. Solvent purity can affect analytical accuracy when the sample 6 Reagent Chemicals, American Chemical Society Specifications, American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed by the American Chemical Society, see Analar Standards fi~r Laboratory Clwmicals, BDH Ltd., Poole, Dorset, U.K., and the Uniled States Pharmacopeia and National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville, MD. Viton (a trademark owned by E. I. duPont de Nemours) tubing has been Ibund satisPaclory and is available from Gilson Medical Electronics, Inc., Mtddleton, Wl 53562. An equivalent can be used.

a Standards from the following source have been found satisfactory for this purposc--Conoco, Inc., Conostan Division, P. O. Box 1269, Ponca City, OK 74603.

949

~

D 5708

ferences cannot be avoided, the necessary corrections should be made using the computer software supplied by the instrument manufacturer or by using the empirical method described in Test Method D 5185. 10.4 Consult the instrument manufacturer's instructions for operating the instrument with organic solvents. 10.5 During instrument warm-up, nebulize the blank solution. Inspect the torch for carbon build-up. When carbon build-up occurs, replace the torch and adjust the operating conditions to correct the problem. 10.5.1 Carbon build-up within the torch can be caused by improperly adjusted argon flow rates, improper solution flow rates, and positioning the torch injector tube too close to the load coil. Carbon deposits can invalidate a calibration and extinguish the plasma.

Infrared Lamp

Vycor Vessel .ah

~

.....,

11. Calibration and Analysis 11.1 Using the blank and working standard, perform a two-point calibration at the beginning of the analysis of each batch of specimens. Additional working standards can be used, if desired. 11.2 Use the check standard to determine if the calibration for each analyte is accurate. When the result obtained on the check standard is not within =1=5% of the expected concentration for each analyte, take corrective action and repeat the calibration. 11.3 Analyze the specimens in the same manner as the calibration standards (that is, same integration time, plasma conditions, and so forth). Calculate concentrations by multiplying the concentration determined for the test specimen solution by the dilution factor. Calculation of concentrations can be performed manually or by computer when such a feature is available. 11.4 When the measured intensities for the test specimen solution exceed the corresponding intensities for the working standard, either ensure that the calibration curve is linear to the concentration of the element in the test specimen solution or dilute the test specimen solution with the blank solution and reanalyze. 11.5 Analyze the check standard after every fifth specimen. If any result is not within 5 % of the expected concentration, take corrective action, repeat the calibration, and reanalyze the specimen solutions back to the previous acceptable check standard analysis. 11.6 The use of spectral background correction is highly recommended, particularly when the test specimen solutions contain low concentrations of the analytes (typically less than 1 mg/kg). When concentrations are low, background changes, which can result from variability in the compositions of test specimen solutions, can affect the accuracy of the analysis. Background correction minimizes errors due to variable background intensities. TEST METHOD Bm ICP AFTER ACID DECOMPOSITION OF SAMPLE

12. Apparatus 12.1 Refer to 7.1 to 7.4. 12.2 Sample Decomposition Apparatus (optional)--This apparatus is shown in Fig. I. It consists of a high-silica or borosilicate 400-mL beaker for the specimen, an air bath (Fig. 2) that rests on a hot plate, and a 250-watt infrared 950

m

Air Bath

Sample

.

J

~Hot FIG. 1

Plate

DecompositionApparatus

lamp supported 1 in. above the air bath. A variable transformer controls the voltage applied to the lamp. 12.3 Glassware, high-silica or borosilicate 400-mL beakers, volumetric flasks of various capacities, and pipettes of various capacities. When determining concentrations below l mg/kg, all glassware must be thoroughly cleaned and rinsed with water. 12.4 Electric Muffle Furnace, capable of maintaining 525 + 25"C and sufficiently large to accommodate 400-mL beakers. The capability of an oxygen bleed is advantageous and optional. 12.5 Steam Bath (optional). 12.6 Temperature Controlled Hot Plate (optional).

13. Reagents 13.1 Aqueous Standard Solutions, individual aqueous standards with 1000 mg/L concentrations of vanadium, nickel, and iron. 13.2 Nitric Acid, concentrated nitric acid, HNO3. 13.3 Nitric Acid (I +/)--Carefully add, with stirring, one volume of concentrated nitric acid to one volume of water. 13.4 Dilute Nitric Acid (19 + /)--Carefully add, with stirring, one volume of concentrated nitric acid to 19 volumes of water. 13.5 Sulfuric Acid, concentrated sulfuric acid, H2SO4. 14. Preparation of Standards 14.1 Blank Standard--Dilute (19 + 1) nitric acid. 14.2 Multi-element StandardmUsing the aqueous standard solutions, prepare a multi-element standard containing 100 mg/L each of vanadium, nickel, and iron. 14.3 Working Standard--Dilute the multi-element standard ten-fold with dilute nitric acid. 14.4 Check Standards--Prepare calibration check standards in the same way as the working standard and at analyte concentrations that are typical of the samples being analyzed.

o sro8 tion. Perform all steps specified in this section. NOTE 4: Caution--Reagent blanks are critical when determining concentrations below I mg/kg. To simplify the analysis, use the same volume of acid and the same dilutions as used for the samples. For example, if 20 g of sample is being decomposed, use 10 mL of sulfuric acid for the reagent blank. 15.3 The use of the air bath apparatus (Fig. 2) is optional. Place the beaker in the air bath, which is located in a hood. The hot plate is off at this time. Heat gently from the top with the infrared lamp (Fig. 1) while stirring the specimen with a glass rod. As decomposition proceeds (indicated by a frothing and foaming), control the heat of the infrared lamp to maintain steady evolution of fumes. Give constant attention to each sample mixture until all risk of spattering and foaming is past. Then, gradually increase the temperatures of both the hot plate and lamp until the sample is reduced to a carbonaceous ash. 15.4 If the air bath apparatus is not used, heat the sample and acid on a temperature controlled hot plate. As described in 15.3, monitor the decomposition reaction and adjust the temperature of the hot plate accordingly. NOTE 5: Precaution--Hot, fuming, concentrated sulfuric acid is a very strong oxidizing acid. The analyst should work in a well-ventilated hood and wear rubber glovesand a suitable face shield to protect against spattering acid. 15.5 Place the sample in a muffle furnace maintained at 525 + 25"C. Optionally, introduce a gentle stream of oxygen into the furnace to expedite oxidation. Continue to heat until the carbon is completely removed. 15.6 Dissolve the inorganic residue by washing down the wall of the beaker with about 10 m L of 1+1 HNO 3. Digest on a steam bath for 15 to 30 min. Transfer to a hot plate and gently evaporate to incipient dryness. 15.7 Wash down the wall of the beaker with about 10 m L of dilute nitric acid. Digest on the steam bath until all salts are dissolved. Allow to cool. Transfer quantitatively to a volumetric flask of suitable volume and make up to volume with dilute nitric acid. This is the specimen solution.

1 t!

6T

==..~1 v

1 "--~ 3 lq

7 tw

3-g 5"

l

j-

~ _ 1 ! ~ 2"

_tq

\_. 1" 4 Fig_

NOTE--All parts are 16-gage (0.060 in., 1.5 mm) aluminum. All dimensions are in inches. Metric Equivalents in.

mm

in.

mm

1 11/2 2 3i/le

25.4 38.1 50.8 77.8

3% 5 61/2

98.4 127 165.1

FIG. 2

16. Preparation of Apparatus 16.1 Refer to 10.1 to 10.3. 17. Calibration and Analysis 17.1 Refer to Section 11. 17.2 Analyze the reagent blank (refer to 15.2) and correct the results obtained on the test specimen solutions by subtracting the reagent blank results.

Air Bath

15. Preparation of Test Specimens 15.1 Into a beaker, weigh an amount of sample estimated to contain between 0.0025 and 0.12 mg of each metal to be determined. A typical mass is 10 g. Add 0.5 mL of H2SO4 for each gram of sample. NOTE 3mlf it is desirable to extend the lower concentration limits of the method, it is recommendedthat the decompositions be done in 10-g increments up to a maximum of 100 g. It is not necessaryto destroy all the organic matter each time before adding additional amounts of sample and acid. When it is desirable to determine higher concentrations, reduce the sample size accordingly. 15.2 At the same time, prepare reagent blanks using the same amount of sulfuric acid as used for sample decomposi-

18. Calculations 18.1 For Test Method A, calculate the concentration of each analyte in the sample using the following equation: analyte concentration, mg/kg = C × F (I) where: C = concentration of the analyte in the specimen solution, mg/kg, and F = dilution factor. 18.2 For Test Method B, calculate the concentration of each analyte in the sample using the following equation: analyte concentration, mg/kg ffi (C x V x F)/W (2) where:

951

q~) D 5708 TABLE 4 Reproducibility NOTE~X -- mean ¢ortcerttratJon,mg/kg.

TABLE 2 Repeatability NOTE~X = mean concentration, mg/kg. Element

Concentration Range, rnglkg

Vanadium

50-500

Test Method A A

0.07X °.u 0.02X 1.1 0.01X 1.s

B

0.02X 1.a

A B

0.22X°.a° 0.23X °.aT

B

Nickel

10-100

Iron

1-10

TABLE 3

Element Vanadium Nickel Iron

Element

Repeatability, rng/kg

Vanadium

10

50

A

2.2

B

1.5

A B A B

0.22 0.23

0.20 0.32 0.44 1.08

1.6 2.2

500

4.0 3.2 4.0 5.0

17 19

A

10-100

Iron

TABLE 5

100

50-500

Nickel

Concentration 1

Test Method

1-10

A B

0.05X ~.a

A B

0.68X°.~ 0.91Xo,sl

Calculated Reproducibility ( m g l k g ) at Selected Conoentmtions (mglkg) Concentration

Element

Test Method

50

100

500

Vanadium

A

8.9

19

B

7.4

16

112 93

15 20

Nickel Iron

1

10

A

2.5

8.7

B

1.0

B.1

A B

C ffi concentration of the analyte in the specimen solution (corrected for the concentration determined in the reagent blank), mg/L V = volume of the specimen solution, mL, F = dilution factor, and W= sample mass, g.

Reproducibility, mg/kg 0.12X 1.1 0.10X 1.1 0.41X°.7"

B

Calculated Repeatability ( m g / k g ) at Selected Concentrations ( m g l k g ) Test Method

Concentration Range, mg/kg

0.68 0.91

1.5 2.9

background correction. Seven samples (four residual oils and three crude oils) comprised the test set. One residual oil was NIST SRM 1618 m, and one crude oil was NIST RM 8505. I° 20.1.1 Repeatability--The difference between two test results, obtained by the same operator with the same apparatus under constant operating conditions on identical test materials would, in the long run, in the normal and correct operation of the test method, exceed the values in Tables 2 and 3 only in one case in twenty. 20.1.2 Reproducibility--The difference between two single and independent results, obtained by different operators working in different laboratories on identical test materials would, in the long run, in the normal and correct operation of the test method, exceed the values in Tables 4 and 5 only in one case in twenty. 20.2 Bias--Bias was evaluated from results obtained on two NIST samples. For Test Methods A and B, the means of the reported values for V and Ni do not differ from the corresponding expected values by more than the repeatability of the test method. Standard reference materials for Fe are not available, so bias was not determined.

19. Report 19.1 Report concentrations in mg/kg to three significant figures.

20. Precision and Bias 9 20.1 PrecisionmThe precision of these test methods was determined by statistical analysis of interlaboratory test results. For Test Method A, eleven cooperators participated in the interlaboratory study. Mixed xylenes, o-xylene, and tetralin were successfully used as dilution solvents. One cooperator noted that when kerosine was used, a precipitate developed in several minutes. All cooperators used a peristaltic pump. Approximately half of the cooperators used a high-solids nebulizer. Approximately half of the cooperators used background correction. For Test Method B, eight cooperators participated in the interlaboratory study. All labs but one used a peristaltic pump. Most labs did not use a high-solids nebulizer. Approximately half of the labs used

21. Keywords 21.1 emission spectrometry; ICP; inductively coupled plasma atomic emission spectrometry; iron; nickel; vanadium

9 Interlaboratory study data are available from ASTM Headquarters. Request RR:D02-135 I.

'OAva/lablc from the National Institute of Standards and Technology, Gaithersburg, MD 20899.

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expresNy advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, ere entirely their own reepousitNIIty. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years a M it not revised, either reapproved or withdrawn. "Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend, ff you feel that your comments have not received • fair hearing you should make your views known to the ASTM Committee on Standards, 100 Berr Harbor Drive, West Conshohocken, PA 19428.

952

(~~ll~ Designation: D 5713 - 96 Standard Test Method for Analysis of High Purity Benzene for Cyclohexane Feedstock by Capillary Gas Chromatography 1 This standard is issued under the fixed designation D 5713; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (~) indicates an editorial change since the last revision or rcapproval.

of the internal standard, and using a response factor of 1.00 for nonaromatic impurities and the amount of internal standard added, the concentrations of the impurities are calculated. The benzene content is obtained by subtracting the total amount of all impurities from 100.00.

1. Scope 1.1 This test method covers the determination of specific impurities in, and the purity of benzene for cyclohexane feedstock by gas chromatography. It is applicable to benzene in the range from 99 to 100 % purity and to impurities at concentrations of 2 to l0 000 mg/kg. 1.2 The following applies to all specified limits in this test method: for purposes of determining conformance with this test method, an observed value or a calculated value shall be rounded off "to the nearest unit" in the last right-hand digit used in expressing the specification limit, in accordance with the rounding-off method of Practice E 29. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For a specific hazard statement, see Section 7 and Note 1.

4. Significance and Use 4.1 This test method is designed to obtain benzene purity on the basis of impurities normally present in benzene and may be used for final product inspections and process control. 4.2 This test method will detect the following impurities: toluene, methylcyclopentane, n-hexane, 2-methylhexane, cyclohexane, cyclopentane, 2-methylpentane, 2,3-dimethylpentane, 3-methylhexane, n-heptane, methylcyclohexane, ethylcyclopentane, 2,4-dimethylhexane, trimethylpentane, and others where specifc impurity standards are available. Absolute purity cannot be accurately determined if unknown impurities are present.

2. Referenced Documents

5. Apparatus 5. l Gas Chromatograph--Any gas chromatograph having a temperature programmable oven, flame ionization detector and a splitter injector suitable for use with a fused silica capillary column may be used, provided the system has sufficient sensitivity that will give a minimum peak height of 3 times the background noise for 2 mg/kg of an impurity when operated at recommended conditions. 5.2 Column--Fused silica capillary columns have been found to be satisfactory. An example is 50 m of 0.20-ram inside diameter fused silica capillary internally coated to a film thickness of 0.50 ~tm with cross-linked methyl silicone (see Table l for parameters). Other columns may be used after it has been established that such a column is capable of separating all major impurities (for example, compounds listed in 4.2) and the internal standard from the benzene under operating conditions appropriate for the column. The column must give satisfactory resolution (distance from the valley between the peaks is not greater than 50 % of the peak heights of the impurity) of cyclohexane from benzene as well as other impurity peaks. A poorly resolved peak, such as cyclohexane, will often require a tangent skim from the neighboring peak. 5.3 Electronic Integration, with tangent skim capabilities is recommended. 5.4 Vial. 5.5 Microsyringes, assorted volumes.

2.1 A S T M Standards: D3437 Practice for Sampling and Handling Cyclic Products2 E 29 Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications 3 E 260 Practice for Packed Column Gas Chromatography3 E 355 Practices for Gas Chromatography Terms and Relationships3 E 1510 Practice for Installing Fused Silica Open Tubular Capillary Columns in Gas Chromatographs3 2.2 Other Document: OSHA Regulations, 29 CFR, paragraphs 1910.1000 and 1910.12004 3. Summary of Test Method 3.1 In this test method, the chromatogram peak area for each impurity is compared to the peak area of the internal standard (n-octane or other suitable known) added to the sample. From the response factor of toluene relative to that This test method is under the jurisdiction of ASTM Committee D-16 on Aromatic Hydrocarbon and Related Chemicals and is the direct responsibility of Subcommittee DI6.0A on Benzene, Toluene, Xylenes, Cyclohexane, and Their Derivatives. Current edition approved Feb. 10, 1996. Published March 1996. Originally published as D 5713 - 95. Last previous edition D 5713 - 95 ° . 2 Annual Book of ASTM Standards, Vol 06.04. 3 Annual Book of ASTM Standards, Vol 14.02. 4 Available from the Superintendent of Documents, U.S. Government Printing Office, Washington, DC 20402.

6. Reagents and Materials 6. l Carrier Gas--a carrier gas (minimum purity of 99.95 953

~ TABLE 1

D 5713

Instrument Typical Parameters

Carder gas Unear velocity at 40°C, cm/s Detector Detector temperature, °C Injection port temperature, °C Split ratio Split flow, mL/min Column Initial column temperature, *C Initial time, mln Programming rate Final temperature, *C Final time, rain Sample size, ~L

9. Procedure 9.1 Follow the manufacturer's instructions for mounting the column into the chromatograph and adjusting the instrument to the conditions described in Table 1. Allow sufficient time for the equipment to reach equilibrium. See Practices E 260, E 355 and E 1510 for additional information on gas chromatography precedures, terminology, and column installation. 9.2 Transfer approximately 10 g of the sample to be analyzed to a tared vial and weigh to the nearest 0.1 mg. (Make sure that the sample is deposited in the center of the vial with a Pasteur pipet so that the liquid does not contact the neck.) 9.3 Add approximately 0.1 g of n-octane internal standard using a Pasteur pipet and quickly reweigh to the nearest 0.1 mg. (The internal standard is added to the vial while on the balance pan and deposited into the center of the liquid--not on the side of the vial.) 9.4 Cap the mixture and mix by inverting several times. 9.5 Inject 1.2 p.l of the sample containing internal standard and immediately start the recorder, temperature programming sequence, and integrator. 9.6 Determine the areas of all the impurity peaks and n-octane. Identify the specific impurities by comparing the chromatogram obtained to the typical chromatogram shown on Fig. 1 (unidentified impurities are summed and reported as a composite).

hydrogen 40 flame ionization 250°C 250°C 40:1 60 50 m by 0.20 mm ID by 0.5 ixm bonded methyl silicone fused silica capillary 40 17 10°C/min 250°C 10 1.2

% mol) appropriate to the type of detector used should be employed. NOTE l--Precaution: If hydrogen is used as the carrier gas, take special safety precautions to ensure that the system is free of leaks and that the effluent is properly vented or burned.

6.2 Hydrogen and Air for the flame ionization detector (FID). 6.3 n-octane, 99.0 % minimum purity, or other internal standard, such as/so-octane, previously analyzed to be free of compounds coeluting with impurities in the sample.

7. Hazards 7.1 Consult current OSHA regulations, suppliers' Material Safety Data Sheets, and local regulations for all materials used in this test method.

10. Calculation 10.1 Measure the areas of all peaks, including the internal standard, except the benzene peak. 10.2 Calculate the weight to milligram per kilogram-mg/kg of the individual impurities, C, as follows:

8. Sampling 8.1 Sample in accordance with Practice D 3437.

G = lO6

BDF GH

b

, I

!i ,,ii !

=-:

I 0 4 Retention "lime, Minutes PIG. 1

I 12

ill

I

I

I

I

16

20

24

28

High Purity Benzene--Typical (See Table 1)

954

Chromatogram

30

~

D 5713 TABLE 2 Intermediate Precision and Reproducibility

where: B = peak area of a specific impurity or group of impurities, D = response factor, (see 10.3), F = mass of n-octane added to the sample, g, G = peak area of the n-octane, H = weight of sample before addition of n-octane, g, and 106 = factor to convert to weight-mg/kg 10.3 A response factor of 1.000 should be used for all hydrocarbon impurities except toluene which will be 0.935. 10.4 Calculate the benzene content by subtracting the sum of the impurities from 100.000. Benzene weight % = 100.000 - (sum of impurities in weight %). Total impurities are converted from mg/kg to weight percent by multiplying by 0.0001%.

Component

Average Concentrationppm Weight %

intermediate Precision

Reproducil~lity

Benzene

99.96 99.97 99,96

0.006 0.007 0.008

0.022 0.020 0.025

Methylcyclopentane

104 43 54

8.3 12.2 2.5

27.9 19.4 15.1

Toluene

64 63 28

5.1 3.0 1.8

22.0 16.6 9.1

Methylcyctohexane

132 43 79

7.4 1.4 3.2

34.8 5.4 17.0

Methylcyclohexane + Toluene

196 106 106

7.9 12.9 4.4

54.9 33.6 20.4

11. Report

n-Hexane

11.1 Report the concentration of impurities to the nearest mg/kg and the benzene content to the nearest 0.01%. For conversion purposes, 1 mg/kg equals 0.0001%.

4 3 2

2.2 1.5 1.8

3.7 2.2 2.5

n-Heptane

6 16 15

2.7 1.5 4.0

11.1 5.6 23.4

Ethylcyclopentane

7

1.8

3,7

6

1.9

11.0

11

1.5

6.1

99 107 185

22.5 44.6 55.5

163,0 190.6 233.0

12. Precision and Bias s 12.1 Precision--The following criteria should be used to judge the acceptability (95 % probability level) of results obtained by this test method. The criteria in Table 2 were derived from an interlaboratory study between six laboratories. Three samples were analyzed in duplicate on two days.

Total Other impurities

differ by more than the amount shown in Table 2. On the basis of test error alone, the difference between two test results obtained in different laboratories on the same material will be expected to exceed this value only 5 % of the time. 12.2 Bias--Since there is no accepted reference material suitable for determining the bias for the procedure in this test method for measuring specific impurities, bias has not been determined.

12. I. 1 Intermediate Precision (formerly Repeatability)Results in the same laboratory should not be considered suspect unless they differ by more than the amounts shown in Table 2. On the basis of test error alone, the difference between two results obtained in the same laboratory on the same material will be expected to exceed this value only 5 % of the time. 12.1.1 Repeatability--Results submitted by each of two laboratories should not be considered suspect unless they

13. Keywords 5 Supporting data are available from ASTM Headquarters. Request RR: Dlr-1018.

13.1 benzene; cyclohexane feedstock; impurities

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend, ff you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 100 Barr Harbor Drive, West Conshohockan, PA 19428.

955

(~T~ Designation: D 5762 - 95 Standard Test Method for Nitrogen in Petroleum and Petroleum Products by Boat-Inlet Chemiluminescence Th~s standard ~s issued under the fixed designation D 5762; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (~) indicates an editorial change since the last revision or reapproval.

1. Scope I. 1 This test method covers the determination of nitrogen in liquid hydrocarbons including petroleum process streams and lubricating oils in the concentration range from 40 to 10 000 Ixg/g nitrogen. For light hydrocarbons containing less than 100 ixg/g nitrogen, Test Method D 4629 can be more appropriate. 1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 2. Referenced Documents

2.1 A S T M Standards: D 4052 Test Method for Density and Relative Density of Liquids by Digital Density Meter a D4057 Practice for Manual Sampling of Petroleum and Petroleum Products 2 D 4177 Practice for Automatic Sampling of Petroleum and Petroleum Products z D 4629 Test Method for Trace Nitrogen in Liquid Petroleum Hydrocarbons by Syringe/Inlet Oxidative Combustion and Chemiluminescence Detection 2 3. Summary of Test Method 3.1 A hydrocarbon sample is placed on a sample boat at room temperature. The sample and boat are advanced into a high-temperature combustion tube where the nitrogen is oxidized to nitric oxide (NO) in an oxygen atmosphere. The NO contacts ozone and is converted to excited nitrogen dioxide (NO2). The light emitted as the excited NO2 decays is detected by a photomultiplier tube and the resulting signal is a measure of the nitrogen contained in the sample. 4. Significance and Use 4.1 Many nitrogen compounds can contaminate refinery catalysts. They tend to be the most difficult class of compounds to hydrogenate so the nitrogen content remaining in the product of a hydrotreator is a measure of the effectiveThis lest method is under the jurisdlclmn of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee I)02.03 on Elemental Analysis ('urrcnt cdtlkm appuoved Aug. 15, 1995. Puhlished October 1995. 2 Annual Book o~ ASTM Standards, Vol 05,02.

956

ness of the hydrotreating process. In lubricating oils the concentration of nitrogen is a measure of the presence of nitrogen containing additives. This test method is intended for use in plant control and in research. 5. Apparatus 5. l Boat Inlet System, capable of being sealed to the inlet of the combustion tube and swept with inert gas. The boats are fabricated from platinum or quartz. To aid quantitative liquid injection, add a small piece of quartz wool to the boat. The boat drive mechanism should be able to fully insert the boat into the furnace tube inlet section. A drive mechanism which advances and withdraws the sample boat into and out of the furnace at a controlled and repeatable rate is required. 5.2 Chemiluminescence Detector, capable of measuring light emitted from the reaction between nitric oxide and ozone, and containing a variable attenuation amplifier, integrator, and readout. 5.3 Combustion Tube, fabricated from quartz. The inlet end of the tube shall be large enough to accept the sample boat and have side arms for introduction of oxygen and inert gas. The construction is such that the carder gases sweep the inlet zone transporting all of the volatilized sample into a high-temperature oxidation zone. The oxidation section should be large enough to ensure complete oxidation of the sample. Combustion tubes recommended for the two furnaces in 5.5.1 and 5.5.2 are described in 5.3.1 and 5.3.2. Other configurations are acceptable if precision and bias are not degraded. 5.3. l Quartz combustion tube for use with the single-zone furnace is illustrated in Fig. 1. A water-jacket around the inlet section can be used to cool the boat prior to sample injection. 5.3.2 Quartz combustion tube for use with the two-zone furnace is illustrated in Fig. 2. The outlet end of the pyrolysis tube is constructed to hold a removable quartz insert tube. The removable quartz insert tube is packed with copper oxide and silver wool, which can aid in completing oxidation. 5.4 Drier Tube, for the removal of water vapor. The reaction products include water vapor that shall be eliminated prior to measurement by the detector. This can be accomplished with a magnesium perchlorate, Mg(CIO4).~, scrubber, a membrane drying tube permeation drier, or a chilled dehumidifier assembly. 5.5 Furnace, Electric, held at a temperature sufficient to pyrolyze all of the sample and oxidize the nitrogen to NO. Either of the following furnace designs can be used. 5.5.1 Single-zone tube furnace with temperature controller capable of maintaining a furnace temperature of

(@) D 5762 892mm 257rnrn

6turn O 0

× 2turn ID

12 r a m

35mm

,,f

50ram

~l 60ram

25ram FIG. 1

6r-rim OD x 2 r a m

ID

Quartz Combustion Tube (Single-Zone Furnace)

f E

/ Jl120~n

130ran

40mm

90mm 160mm 200mm FIG. 2

Quartz Combustion Tube (Two-Zone Furnace)

reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination. 6.2 Acridine, CI3H9N, molecular weight 179.21, 7.82 mass % nitrogen.

1100°C. Included in the furnace assembly are needle valves for gas flow control. 5.5.2 Two-zone tube furnace with temperature controllers capable of maintaining the temperature of each furnace zone independently to 1050°C. Included in the furnace assembly are flow restrictors for gas flow control. 5.6 Microlitre Syringe, of 5 or 10-gL capacity, capable of accurately delivering microlitre quantities. 5.7 Ozone Generator, to supply ozone to the detector reaction cell. 5.8 Recorder (Optional), for display of chemiluminescence detector signal.

NOTE 1: W a r n i n g - - I r r i t a n t .

6.3 Cupric Oxide Wire, CuO, as recommended by the instrument manufacturer. 6.4 Inert Gas--Argon or Helium only, high-purity grade (that is, chromatographic or zero grade), 99.998 % minimum purity, 5 ppm maximum moisture. 6.5 Anhydrous Magnesium Perch/orate, Mg(CIO4)> for drying products of combustion (if permeation drier or chilled drier is not used).

6. Reagents and Materials

NOTE 2: Warning--Strong oxidizer, irritant.

6.1 Purity q[Reagents--Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society where such specifications are available? Other grades may be used, provided it is first ascertained that the

6.6 Nitrogen Stock Solution, 500 ng nitrogen/laL--Accurately weigh (to the nearest 0.1 rag) approximately 0.64 g of acridine into a tared 100-mL volumetric flask. Add xylene to dissolve, then dilute to volume with xylene. Calculate the nitrogen content of the stock solution to the nearest milligram of nitrogen per litre. This stock can be further diluted to desired nitrogen concentrations.

"~Reagent Chemicals. Amertcan Cbemwa/ Sactety Speci[icattons, American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed by the American Chemical Society, see Analar Standards .[br Laboratory ('hemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pbarmacopeia and Nattomd I.'ormalarv, U.S. Pharmaceutical Conventmn, Inc. (USPC), Rockvlllc, MD

NOTE 3: Caution--Remake standard solutions on a regular basis depending upon frequency of use and age. Typically,standards have a useful life of approximatelythree months. 6.7 Oxygen, high-purity grade (that is, chromatographic 957

o 5782 9. Calibration and Standardization 9.1 Prepare calibration standards containing 1, 5, 10, 50, and 100 ng nitrogen/laL in xylene by volumetric dilution of the 500-rig nitrogen/IxL nitrogen stock solution. 9.2 Five microlitres of the material to be analyzed (see Note 10) shall be quantitatively placed in the sample boat for measurement of chemiluminescence response. There are two alternative injection procedures available, the volumetric and the gravimetric procedures.

or zero grade), 99.75 % minimum purity, 5 ppm maximum moisture, dried over molecular sieves. NOTI'."4: WarningmVigorously acceleratescombustion. 6.8 Quartz Wool. 6.9 Silver Wool, as recommended by the instrument manufacturer. 6.10 Xylene. NOTE 5: Warning--Flammable, health hazard.

NOTE 10--The formation of NO and NO2 from oxidative combustion of nitrogen containing hydrocarbons is dependent on combustion conditions such as temperature and oxygen concentration. Injection of a constant solution volume, and dilution of all test specimens and standards with a common solvent, maintain consistent combustion conditions for test specimens and standards.

7. Sampling 7.1 Obtain a test sample in accordance with Practice D 4057 or D 4177. NOTE 6: Warning--Samples that are collected at temperatures below room temperature can undergo expansion at laboratory temperatures and rupture the container. For such samples, do not fill the container to the top. Leave sufficient air space above the sample to allow room for expansion. Norr.. 7: Caution--To minimize loss of volatile components which can be present in some test samples, do not uncover any longer than necessary. Test samples should be analyzed as soon as possible after taking from bulk supplies to prevent loss of nitrogen or contamination due to exposure or contact with sample container.

9.2.1 For volumetric measurement of the material by microlitre syringe, flush the microlitre syringe several times with the material, discarding the flushed liquid each time. Fill the 10-p.L syringe to the 5-1aL level. Retract the plunger so that the lower liquid meniscus falls on the 10 % scale mark. When bubbles are present within the liquid column, flush the syringe and withdraw a new aliquot of the liquid. Record the volume of liquid in the syringe. Immediately inject the liquid into the boat, being careful to displace the last drop by touching the edge of the boat, or the quartz wool if present, with the syringe needle. After the injection, again retract the plunger so that the lower liquid meniscus falls on the 10 % scale mark and record the volume of liquid in the syringe. The difference between the two volume readings is the volume of liquid injected.

7.2 If the test sample is not used immediately, then thoroughly mix it in its container prior to taking a test specimen. Some test samples require heating in order to thoroughly homogenize. 8. Preparation of Apparatus 8.1 Assemble apparatus in accordance with the manufacturer's instructions. 8.2 Adjust the oxygen flow for the ozone generator in accordance with the manufacturer's instructions. Adjust the combustion tube gas flows and the pyrolysis temperature to the desired operating conditions using the following guidelines for each furnace type.

NOTE I l--An automatic sampling and injection device can be used in place of the described manual injection procedure.

NOTE 8: Warning--Ozone is extremely toxic. Make sure that appropriate steps are taken to prevent discharge of ozone within the laboratory work area. 8.2.1 For the single-zone furnace, adjust the combustion tube gas flows to the following values: pyrolysis oxygen, 360 mL/min; inlet oxygen, 60 mL/min; and inert carrier inlet, 155 mL/min. Set the furnace temperature to 1100 _+ 25"C. Adjust the boat drive mechanism to obtain a drive rate of 150 __. 10 mm/min. Refer to the manufacturer's instructions for descriptions of these settings. 8.2.2 For the two-zone furnace, adjust the combustion tube gas flows to the following values: combustion oxygen, 165 mL/min; inlet inert carrier, 85 mL/min; and boat inert carrier, 50 mL/min. Set the inlet furnace temperature to 1050 + 25"C, and the outlet furnace temperature to 925 _.+ 25"C. Adjust the boat drive mechanism to obtain a drive rate of 150 :t: 10 mm/min (boat speed number 4). Refer to the manufacturer's instructions for the description of these settings. NOTE 9: Warning--High temperature is employed in this test method. Use flammable materials with care near the pyrolysis furnace. 8.3 Insert boat into furnace for a minimum of 2 min to remove any residual nitrogen species. 958

9.2.2 For gravimetric measurement of the solution, fill the syringe as indicated in 9.2.1. Weigh the microlitre syringe and its contents and record the mass to the nearest 0.01 mg. Immediately inject the liquid into the boat, being careful to displace the last drop by .touching the edge of the boat, or quartz wool if present, with the syringe needle. After the injection, remove the syringe and again weigh the syringe and its contents. Record the mass to the nearest 0.01 mg. The difference between the two weighings is the mass of liquid injected. The gravimetric procedure is more precise than the volumetric procedure, provided a balance with a precision of -0.01 mg is used. 9.3 Activate the boat drive mechanism to insert the boat into the furnace. The instrument baseline should remain stable until the boat approaches the furnace and volatilization of injected material begins. After the measurement is complete, retract the boat. The instrument baseline should reestablish before the boat has completely emerged from the furnace. Record the integrated chemiluminescence response. Allow the boat to cool for at least 1 min before the next injection. 9.4 Calibrate the instrument using one of the following two techniques. 9.4.1 Perform measurements for the calibration standards and blank using the procedure described in 9.2 and 9.3. Measure the calibration standards and blank three times each and determine the average integrated chemiluminescence response for each. Construct a curve plotting

t~) D 5762 average integrated detector response (y-axis) versus nanograms of nitrogen injected (x-axis). 9.4.2 If the system features an internal calibration routine, measure the calibration standards and blank three times each using the procedure described in 9.2 and 9.3. Calibrate the analyzer in accordance with the manufacturer's instructions using the average of the three measurements for each standard and blank. 9.5 If analyzer calibration is performed using only a subset of the calibration standards listed in 9.1, the calibration standards closest in concentration to the measured solution(s) must be included in the subset (that is, if the concentration of the test specimen solution is 20 ng nitrogenAtL, include the 10 and 50-ng nitrogen/laL standards in the calibration). System performance must be checked with the calibration standards at least once per day.

the residence time for the boat in the furnace if coke or soot is observed on the boat. Decrease the boat drive introduction rate if coke or soot is observed on the exit end of the combustion tube. Clean any coked or sooted parts. After any cleaning or adjustment, repeat instrument calibration prior to reanalysis of the test specimen. 11.5 Measure each test specimen solution three times and calculate the average chemiluminescence response. 12. Calculation 12.1 For analyzers calibrated using a standard curve, calculate the nitrogen content of the test specimen in micrograms per gram (lag/g) as follows: ( i - Y) Nitrogen, (p.g/g) = (I) SxMXKg or,

10. Quality Assurance 10.1 A sample of known nitrogen content will be run after each calibration. The sample can also be analyzed periodically throughout a series of analyses to check the functioning of the instrument and the validity of the calibration curve. This sample can be an National Institute for Standards and Tcchnology Standard Reference Material (SRM) material, an acridine in xylene standard prepared to have a nitrogen value not used to calibrate the instrument, or any other material that has been analyzed repeatedly such that sufficient data are available to determine a statistical mean. The rcsults of the analysis of the known sample will be within 10 % of the certified or accepted value for the operation and calibration of the instrument to be considered acceptable. If thc results are not within 10 % of the accepted value, perform appropriate corrective maintenance on the instrument and repeat the calibration procedure described in 9.4.

Nitrogen, (lag/g) =

( I - Y) Sx VxK v

(2)

where: D = density of test specimen solution, g/mL, 1 = average of integrated detector response for test specimen solution, counts (or found ng nitrogen), Kg = gravimetric dilution factor, mass of test specimen/ mass of test specimen and solvent, g/g, K,. = volumetric dilution factor, mass of test specimen/ volume of test specimen and solvent, g/mL, M = mass of test specimen solution injected, either measured directly or calculated from measured volume injected and density, V × D, mg, S = slope of standard curve, counts/ng nitrogen (or found ng nitrogen/ng nitrogen), V = volume of test specimen solution injected, either measured directly or calculated from measured mass injected and density, M/D, laL, and Y = y-intercept of standard curve, counts (or found ng nitrogen). 12.2 For analyzers calibrated using an internal calibration routine, calculate the nitrogen content of the test specimen in micrograms/gram (Ixg/g) as follows: I Nitrogen, (lag/g) = ~ (3) MxKs, or,

I 1. Procedure 11.1 Obtain a test specimen using the procedure described in Section 7. Prepare a test specimen solution by dilution of the test specimen in xylene. Use a dilution factor of at least 1:5 (see Note 10). The nitrogen concentration in the test specimen solution shall be less than the concentration of the highest standard used in calibration and greater than 3 ng nitrogen/laL. The dilution can be performed either on a weight or volume basis, 11.1.1 For gravimetric dilution, record the mass of the test specimen and the total mass of the test specimen and solvent. 11.1.2 For volumetric dilution, record the mass of the test specimen and the total volume of the test specimen and solvent. 11.2 Measure the chemiluminescence response for the test specimen solution using the procedure described in 9.2 and 9.3. 11.3 If the chemiluminescence response from the test specimen solution is greater than the response from the highest calibration standard used, repeat the test specimen dilution described in 11.1 using a higher dilution factor. Repeat the analysis procedure described in 9.2 through 9.3 on this new test specimen solution. 11.4 Inspect the boat and combustion tube to verily complete combustion of the test specimen solution. Increase

I Nitrogen, (p.g/g) = ~ VxKv

(4)

where: D = density of test specimen solution, g/mL, I = average of visual display readings of test specimen solution, ng nitrogen, Kg = gravimetric dilution factor, mass of test specimen/ mass of test specimen and solvent, g/g, K,. = volumetric dilution factor, mass of test specimen/ volume of test specimen and solvent, g/mL, M = mass of test specimen solution injected, either measured directly or calculated from measured volume injected and density, V x D, mg, and V = volume of test specimen solution injected, either measured directly or calculated from measured mass injected and density, M/D, laL.

959

I~) D 5762 and independent results obtained by different operators working in different laboratories on identical test material would, in the long run, in the normal and correct operation of the test method, exceed the following values in only 1 case in 20, where X = the average of the two test results.

13. Precision and Bias 4 13.1 Repeatability--The difference between two test results obtained by the same operator with the same apparatus under constant operating conditions on identical test material would, in the long run, in the normal and correct operation of the test method, exceed the following values in only 1 case in 20, where X = the average of the two test results. r = 0.099x X/.tg/g 13.2

R = 0.291x X ~tg/g 13.3 Bias--An NIST SRM was analyzed by the cooperators participating in the repeatability and reproducibility determination. This test method showed no significant bias for this sample within the repeatability of this test method.

Reproducibility--The difference between two single

14. Keywords 14.1 chemiluminescence; nitrogen

4 Supporting cooperative data are available from ASTM Headquarters. Request RR:D02-1370.

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend, if you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 100 Barr Harbor Drive, West Conshohocken, PA 19428.

960

~fll~ Designation: D 5769 - 95 Standard Test Method for Determination of Benzene, Toluene, and Total Aromatics in Finished Gasolines by Gas Chromatography/Mass Spectrometry 1 This standard is issued under the fixed designation D 5769; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (~) indicates an editorial change since the last revision or reapproval.

E 355 Practice for Gas Chromatography Terms and Relationships4

1. Scope 1.1 This test method covers the determination of benzene, toluene, and total aromatics in finished motor gasoline, including reformulated gasoline (RFG) containing oxygenated blending components, by gas chromatography/mass spectrometry (GC/MS). 1.2 This test method is applicable to the following concentration ranges, in liquid volume %, for the following aromatics: benzene, 0.1 to 3 %; toluene, l to 15 %; and total (C6-C12) aromatics, l0 to 40 %. The test method has not been tested by ASTM for gasoline samples containing a concentration of uncalibrated C10-C12 aromatic compounds greater than approximately 3 volume %. Also, the test method has not been tested by ASTM for individual hydrocarbon process streams in a refinery, such as reformates, fluid catalytic cracked naphthas, etc., used in blending of gasolines. 1.3 Results are reported to the nearest 0.01% for benzene and 0.1% for the other aromatics by either mass or liquid volume. 1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

3. Terminology 3.1 Descriptions of Terms Specific to This Standard." 3. I. 1 aromatic--in this test method, refers to any organic compound containing a benzene or naphthalene ring. 3.1.2 calibrated aromatic componentmin this test method, refers to the individual aromatic components which have a specific calibration. 3.1.3 cool on-column injectormin gas chromatography, a direct sample introduction system which is set at a temperature at or below the boiling point of solutes or solvent on injection and then heated at a rate equal to or greater than the column. Normally used to eliminate boiling point discrimination on injection or to reduce adsorption on glass liners within injectors, or both. The sample is injected directly into the head of the capillary column tubing. 3.1.4 open split interfaceDGC/MS interface used to maintain atmospheric pressure at capillary column outlet and eliminates mass spectrometer vacuum effects on the capillary column. Can be used to dilute the sample entering the mass spectrometer to maintain response linearity. 3.1.5 reconstructed ion chromatogram (RICJma limited mass chromatogram representing the intensities of ion mass spectrometric currents for only those ions having particular mass to charge ratios. Used in this test method to selectively extract or identify aromatic components in the presence of a complex hydrocarbon matrix, such as gasoline. 3.1.6 split ratio--in capillary gas chromatography, the ratio of the total flow of carrier gas to the sample inlet versus the flow of the carrier gas to the capillary column, expressed by split ratio = (S + C)/C (l) where: S = the flow rate at the splitter vent, and C = the flow rate at the column outlet. 3.1.7 total ion chromatogram (TIC)Dmass spectrometer computer output representing either the summed intensities of all scanned ion currents or a sample of the current in the ion beam for each spectrum scan plotted against the corresponding spectrum number. Generally, it can be correlated with a flame ionization detector chromatogram. 3.1.8 uncalibrated aromatic component~in this test method, refers to individual aromatics for which a calibra-

2. Referenced Documents 2.1 A S T M Standards: D 1298 Practice for Density, Relative Density (Specific Gravity), or API Gravity of Crude Petroleum and Liquid Petroleum Products by Hydrometer Method2 D 4052 Test Method for Density and Relative Density of Liquids by Digital Density Meter 3 D4057 Practice for Manual Sampling of Petroleum and Petroleum Product 3 D 4307 Practice for Preparation of Liquid Blends for Use as Analytical Standards 3 J This test method is under the jurisdiction of ASTM Committee I)-2 o n Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.04 on Hydrocarbon Analysis. Current edition approved Sept. 10, 1995. Published November 1995. 2 Annual Book of ASTM Standards, Vol 05.01. Annual Book of ASTM Standards, Vol 05.02.

4 Annual Book of ASTM Standards, Vol 14.02.

961

(~ D 5769 tion is not available. These components are estimated from the calibration of several calibrated aromatic components. 3.1.9 WCOTnwall coated open tubular, a type of capillary column prepared by coating or bonding the inside wall of the capillary with a thin film of stationary phase. 4. Summary of Test Method 4.1 A gas chromatograph equipped with a methylsilicone WCOT column is interfaced to a fast scanning mass spectrometer which is suitable for capillary column GC/MS analyses. The sample is injected either through a capillary splitter port or a cool on column injector capable of introducing a small sample size without overloading the column. The capillary column is interfaced directly to the mass spectrometer or by way of an open split interface or other appropriate device. 4.2 Calibration is performed on a mass basis, using mixtures of specified pure aromatic hydrocarbons. Volume percent data is calculated from the densities of the individual components and the density of the sample. A multipoint calibration consisting of at least five levels and bracketing the expected concentrations of the specified individual aromatics is required. Specified deuterated hydrocarbons are used as the internal standards, for example, d6-benzene for quantitating benzene. Unidentified aromatic hydrocarbons present which have not been specifically calibrated for are quantitated using the calibration of an adjacent calibrated compound and summed with the other aromatic components to obtain a total aromatic concentration of the sample. 4.3 Specified quality control mixture(s) must be analyzed to monitor the performance of the calibrated GC/MS system. 5. Significance and Use 5.1 Test methods to determine benzene and the aromatic content of gasoline are necessary to assess product quality and to meet new fuel regulations. 5.2 This test method can be used for gasolines that contain oxygenates (alcohols and ethers) as additives. It has been determined that the common oxygenates found in finished gasoline do not interfere with the analysis of benzene and other aromatics by this test method. 6. Apparatus and Materials

be less than one-fifth the peak width at half height, that is, there must be at least five full scans across the peak at half height. 6.2.2 The mass spectrometer must be capable of being interfaced to a gas chromatograph and WCOT columns. The interface must be at a high enough temperature to prevent condensation of components boiling up to 220"C, usually 20°C above the final column temperature is adequate. Direct column interface to the mass spectrometer can be used. An open split interface with computer controlled programmable flow controller(s) can also be used, particularly with cool on-column injections, to maintain all aromatic components within the linearity of the mass spectrometer and at the same time maintain detectability of lower concentration aromatic components. For example, a higher open-split-interface make-up gas flow can be used for the high concentration components such as toluene and xylenes, and a lower make-up gas flow rate may be used during the elution of the lower concentration benzene and C9+ components. Other interfaces may be used provided the criteria of Sections 9 and 10 are met. 6.2.3 A computer system must be interfaced to the mass spectrometer to allow acquisition of continuous mass scans or total ion chromatogram (TIC) for the duration of the chromatographic program. Software must be available to allow searching any GC/MS run for specific ions or reconstructed ions and plotting the intensity of the ions with respect to time or scan number. The ability to integrate the area under a specific ion plot peak is essential for quantitation. The quantitation software must allow linear least squares or quadratic nonlinear regression and quantitation with multiple internal standards. It is also recommended that software be available to automatically perform the identification of aromatic components as specified in 13.1.1. 7. Reagents and Materials 7.1 Carrier GasnThe recommended minimum purity of the carrier gas used is 99.85 mole %. Additional purification using commercially available scrubbing reagents may be necessary to remove trace oxygen which may deteriorate the performance of the GC WCOT. Helium and hydrogen have been used successfully. NOTE 1: WarningmHelium and hydrogen are supplied under high pressure. Hydrogen can be explosive and requires special handling. Hydrogen monitors that automatically shut off supply to the GC in case of serious leaks are available from GC supply manufacturers.

6.1 Gas Chromatography." 6.1.1 Gas Chromatographic System, equipped with temperature programmable gas chromatograph suitable for split injections with WCOT column or cool-on-column injector which allows the injection of small (for example, 0.1 ~L) samples at the head of the WCOT column or a retention gap. An autosampler is m~ndatory for the on-column injections. 6.1.2 WCOT Column, containing 100 % methylsilicone bonded stationary phase. For on-column injections a column containing a thicker film of stationary phase, such as 4 to 5 micron, is recommended to prevent column sample overload.

7.2 Standards for Calibration and Identification--Aromatic hydrocarbons used to prepare standards should be 99 % or greater purity (Table 1). If reagents of high purity are not available, an accurate assay of the reagent must be performed using a properly calibrated GC or other techniques. The concentration of the impurities that overlap the other calibration components must be known and used to correct the concentration of the calibration components. Because of the error that may be introduced from impurity corrections, the use of only high purity reagents is strongly recommended. Standards are used for calibration as well for establishing the identification by retention time in conjunction with mass spectral match (13.1.1 ). 7.3 Internal Standards--Deuterated analogs of benzene,

6.2 Mass Spectrometry." 6.2.1 Mass Spectrometer, capable of producing electron impact spectra at 70 or higher electron volts or equivalent and capable of scanning the range of the specified quantitation masses or m/e. The scan time in seconds must 962

~

D 5769 8. Sampling 8.1 Every effort should be made to ensure that the sample is representative of the fuel source from which it is taken. Follow the recommendations of Practice D 4057 or its equivalent when obtaining samples from bulk storage or pipelines. Sampling to meet certain regulatory specifications may require the use of specific sampling procedures. Consult appropriate regulations. 8.2 Appropriate steps should be taken to minimize the loss of light hydrocarbons from the gasoline sample while sampling and during analyses. Upon receipt in the laboratory, chill the sample in its original container to 0 to 5"C (32 to 40*F) before and after a sample aliquot is removed for analysis. 8.3 After the sample is prepared for analysis with internal standard(s), chill the sample and transfer to an appropriate autosampler vial with minimal headspace. The remainder of the sample should be re-chilled immediately and protected from evaporation for further analyses, if necessary. The autosampler vials should be chilled until ready for analyses.

TABLE 1 GC/MS Calibration Components (Calibrated Aromatic Components) Compound

CAS Number

Benzene Methylbenzene Ethylbenzene

71-43-2 108-88-3 100-41-4

1,3-Dimethylbenzene

108-38-3

1,4-D=methylbenzene 1,2-Dimethylbenzene (1-Methylethyl)-benzene Propyl-benzene 1-Methyl-3-ethylbenzene 1-Methyl-4-ethylbenzene t ,3,5-Trimethylbenzene 1-Methyl-2-ethylbenzene 1,2,4-Trimethylbenzene 1,2,3-Tdmethylbenzene Indan 1,4-Diethylbenzene Butylbenzene 1,2-Diethylbenzene 1,2,4,5-Tetramethylbenzene 1,2,3,5-Tetramethylbenzene Pentamethytbenzene Naphthalene 2-Methyl-Naphthalene 1-Methyl-Naphthalene

106-42-3 95-47-6 98-82-8 103-65-1 620-14-4 622-96-8 108-67-8 611-14-3 95-63-6 526-73-8 496-11-7 105-05-5 104-51-8 135-01-3 95-93-2 527-53-7 700-12-9 91-20-3 91-57-6 90-12-0

ethylbenzene and naphthalene as specified in Table 2 must be used as internal standards because of their similar chromatographic characteristics as the components analyzed. 7.4 Dilution Solvents--2,2,4-trimethylpentane (isooctane), n-heptane, n-nonane, cyclohexane or methylbenzene (toluene), or both, used as a solvent in the preparation of the calibration mixtures. Reagent grade. Free from detectable aromatics which may interfere with the analysis. NOTE 2: Warning--The gasoline samples and solvents used as reagents such as /so-octane, cyclohexane, n-heptane, n-octane and toluene are flammable and may be harmful or fatal if ingested or inhaled. Benzene is a known carcinogen. Use with proper ventilation. Safety glasses and gloves are required while preparing samples and standards. Samples should be kept in laboratory areas with single pass air handling and an automatic fire suppression system.

TABLE 2 Compound Benzene Methylbenzene Ethylbenzene 1,3-Dimethylbenzene 1,4-Dimethylbanzene 1,2-Dimethylbenzene (1-Methylethyl)-benzane Prowl-benzene 1-Methyl-3-ethylbenzene 1-Methyl-4-ethylbenzene 1,3,5-Trimethylbenzene

1-Methyl-2-ethylbenzene 1,2,4-Trimethylbenzene 1,2,3-Trimethylbenzene Indan 1,4-Diethylbenzene Butylbenzene 1,2-Diethylbenzene 1,2,4,5-Tetramethylbenzene 1,2,3,5-Tetramethylbenzane Pentamethylbenzene Naphthalene 2-Methyl-Naphthalene 1-Methyl-Naphthalene

9. Calibration 9.1 Preparation of Calibration Standards--Multi-component calibration standards using all the compounds listed in Table 1 are prepared by mass according to Practice D 4307. The standards may be prepared by combining the specified individual aromatics either into a single mixture or into multiple sets. Multiple sets may be prepared as follows: (1) Set I consists of benzene, methylbenzene (toluene), ethylbenzene, 1,2-dimethylbenzene, 1,3-dimethylbenzene and 1,4-dimethylbenzene using 2,2,4-trimethylpentane (isooctane) as a recommended dilution solvent; (2) Set II consists of the remaining C9+ components using a 50:50 mixture of 2,3,3-trimethylpentane and methylbenzene (toluene) as the recommended dilution solvent. Other solvents, such as n-nonane, or co-solvents may be used to improve solubility, chromatographic or mass spectrometric performance, provided these solvents contain no detectable

Mass Spec Quantitation Ions for Sample Components and Internal Standards Primary Ion (Dalton)

Intemal Standard (ISTD)

78 91 106 106 106 106 120 120 120 120 120 120 120 120 117 134 134 134 134 134 148 128 142 142

Benzene-d6 Ethylbenzene-dl 0 or Methylbenzene-d8 Ethylbenzene-dl 0 Ethylbenzene-dl 0 Ethylbenzene-dl 0 Ethylbenzene-dl 0 Ethylbenzene-dl 0 Ethylbenzene-dl0 Ethylbenzene-dl0 Ethylbenzene-dl0 Ethylbenzene-dl 0 Ethylbenzene-dl0 Ethylbenzene-dl0 Ethylbenzene-dl0 Ethylbenzene-dl 0 Naphthalene-el8 Naphthalene-d8 Naphthalene-d8 Naphthalene-d8 Naphthalene-d8 Naphthalene-d8 Naphthalene-d8 Naphthalene-d8 Naphthalene--d8

963

ISTD Ion (Dalton) 84 116 or 100 116 116 116 116 116 116 116 116 116 116 116 116 116 136 136 136 136 136 136 136 136 136

(@) D 5769 amounts of aromatics that will interfere with the analyses. NOTE 3 m l t may be more convenient to prepare gravimetrically pure (solvent free) batches of Set I and Set 11 components which then can be weighed into appropriate diluted standards.

9.1.1 The internal standards for Set I are benzene-d6 and ethylbenzene-dl0. Methylbenzene-d8 may be used for the quantitation of toluene. The internal standards for Set II are ethylbenzene-d 10 and naphthalene-d8. NOTE 4--Appropriate internal standards batches may be prepared and then added to calibration standards and samples in a single step.

9.1.2 A minimum of five calibration solutions must be prepared by mass for single mixtures containing all of the specified calibration compounds. If the calibration solutions are prepared in sets, then for each set five separate solutions must be prepared over the desired concentration range, for example: five calibration solutions for Set I, and five calibration solutions for Oci ~~, L. . I I . T.t.,~ -:I V. .~.I. . L '-~ I I~LULK; 3 ~ IllE; II:;q~UIII" mended volumes to be weighed into 100-mL volumetric flasks or 100-mL septum capped vials for the most concentrated calibration standard. Adjust these concentrations, as necessary, to ensure that the concentrations of the components in the actual samples are bracketed by the calibration concentrations. Solid components are weighed directly into the flask or vial. Other more dilute standards are prepared separately by weighing appropriate amounts of the pure aromatic components. 9.1.2.1 Prepare a calibration standard according to Practice D 4307 as follows: 9.1.3 Cap and record the tare weight of the 100-mL volumetric flask or vial to 0. l rag. 9.1.4 Remove the cap and carefully add an aromatic TABLE 3

Compound

Benzene Methylbenzene Ethylbenzene 1,3-Dimethylbenzene 1A-Dimethylbenzene 1,2-Dimethylbenzene (1-Methylethyl)-benzene Propyl-benzene 1-Methyl-3-ethylbenzene 1-Methyl-4-ethylbenzene 1,3,5-Trimethylbenzene 1-Methyl-2-ethylbenzene 1,2,4-Trimethylpenzene 1,2,3-Trimethylbenzene Indan 1,4-Diethylbenzene Butylbenzene 1,2-Diethylbenzene 1,2,4,5-Tetramethylbenzene 1,2,3,5-Tetramethylbenzene Pentamethylbenzene Naphthalene 2-Methyl-Naphthalene 1-Methyl-Naphthalene Uncahbrated indans Uncalibrated C10-benzenes Uncalibrated C11 benzenes Uncalibrated C12-benzenes

Relative Densities and Calibration Concentrations

Relative Density 60°F/60OF

0.8845 0 8719 0.8718 0.8688 0 8657 0.8846 0.8664 0.8665 0.8691 0.8657 0.8696 0.8851 0.8803 0.8987 0.9689 0.8664 0.8646 0 8843 0.8915 0.8946 0.9204 1.000 1.000 1.0245 1.000 0.878 1.000 1.000

component to the flask or vial starting with the least volatile component. Cap the flask and record the net mass (Wi) of the aromatic component added to 0.1 mg. 9.1.5 Repeat the addition and weighing procedure for each aromatic component. 9.1.6 If Sets I and II components were pre-mixed by weight, then to each calibration solution volumetric flask or vial, weigh appropriate volumes to yield the ten calibration solutions. Calculate the actual weight of each component by multiplying the total mass added of the combined mixture by the mass fraction of the individual components in the pre-mixed undiluted mixture. 9.1.7 Similarly add each internal standard and record its net mass (Ws) to 0.1 mg. If standards are prepared in multiple sets, then for Set I weigh 2 mL each of benzene-d6 and ethyibenzene-dl0. For Set II weigh 2 mL of ethylbenzene-dl0 and l g naphthalene-d8. 9. !.8 Dilute to !00-mL total vo!,ame the standard with the recommended solvents above, or equivalent. It is not necessary to weigh the amount of solvent added since the calculations are based on the absolute masses of the aromatic and internal standard components. 9.1.9 Similarly prepare four additional standards to cover the concentration range of interest. For example, for benzene, prepare 0.1, 0.5, 1.0, 1.5, 3.0 weight % standards; for toluene, prepare 1.0, 3.0, 5.0, 10.0, 15.0 mass % equivalent standards. 9.1.10 Store the capped calibration standards in a refrigerator at 0 to 5°C (32 to 40*F) when not in use. 9.1.11 Thoroughly mix the prepared standards using a vortex mixer or equivalent and transfer approximately 2 mL of the solution to a vial compatible with the autosampler, if

Concentrst=on S for Most Concentrated Calibration Solutions (Volume % or mL/100 mL) 3 15 5 6 6 6 3 3 3 3 3 3 5 3 3 3 3 3 3 2 2"* 2"* 2A 2 ... .

Calibration Components Prepared Into a Single Mixture Set 1 Set 1 Set 1 Set 1 Set 1 Set 1 Set 1 Set 1 Set 1 Set 1 Set 1 Set 1 Set 1 Set 1 Set 1 Sat 1 Set 1 Set 1 Set 1 Set 1 Set 1 Set 1 Set 1 Set 1

.

.

. .

.

.

"* These components are solids at ambient temperature. The values represent grams/100 mL.

964

. .

.

.

. .

.

Mixtures Set 1 Set 1 Sat 1 Set 1 Set 1 Set 1 Set 2 Set 2 Set 2 Set 2 Sat 2 Set 2 Set 2 Set 2 Set 2 Set 2 Set 2 Set 2 Sat 2 Set 2 Set 2 Set 2 Set 2 Set 2

. .

Calibration Components Prepared Into Two Sets of

.

.

@ D 5769 such equipment is used (see 5.1.1 ). Chill the vials until ready for loading on the autosampler.

TABLE 4

Conditions 1 Gas Chromatography (GC): Column

Nol L 5 - - F h g h l y precise robotic or s e m i - a u t o m a t e d sample preparanon systems are available commercially. These systems m a y be used to prepare calibration standards and samples for analyses provided that the results for the quality control reference material (Section 10) are met when prepared using the a u t o m a t e d systems.

2(l 2 - ll)

1.699(3,= + y.) where: I~ = retention time of 1,3,5-trimethylbenzene, t2 = retention time of l-methyl-2-ethylbenzene, Y2 = peak width at half height of 1,3,5-trimethylbenzene, and y= = peak width at half height l-methyl-2-ethyl benzene. 9.2.4 Prepare a solution of 0.01 mass % of 1,4-diethylbenzene and verify that it is detected with a signal:noise ratio of greater than 3. 9.2.5 Inject a solution of 3 mass % of 1,2,3-trimethylbenzene and confirm that the mass spectrometer provides a fragmentation pattern as specified in Table 5. 9.2.6 Sequentially analyze the calibration standards. 9.3 Calibration Calculations: 9.3.1 After the analyses of the calibration standards are complete, integrate the peak area of each calibration component and internal standards using the reconstructed ion chromatogram (RIC) of the characteristic calibration ion listed in Table 2. Obtain the area under the extracted ion at the retention time of the expected aromatic component (or internal standard). 9.3.2 Plot the response ratio rsp,: rsp, = (A,/A~)

60 m x 0.32 mm i.d., df = 5.0 lam methylsilicone cool on-column 0.1 track oven

temperature 50*C (0 min), 2=C/min to 190=C (0 min); 30*C/min to 300*C (1 min). Hydrogen 42 at 3000C

Oven temperature

50°C (1 min), 2*C/mm to 190 (0 mm)

Carrier gas Carrier gas linear velocity (cm/s) GC/MS Interface: GC/MS interface type

Helium 35 at 50"C

Interface temperature (C) Mass Spectrometry (MS): MS type MS data acquisition mode Scan rate (s/scan) Source temperature (C) Ionization voltage (eV) Mass scan range

280

open-split with variable flow 280

quadrupole full scan >1 approximately 250 70 45-300

quadrupole full s c a n >1 approximately 250 70 45-300

direct

A The above are approximate conditions. Fine tuning may be required to meet the criteria (detectability, resolution, etc.) specified in the test method. The items in italics are fixed operating conditions and must be used as indicated.

calibration. The value ta should be at least 0.99 or better and is calculated as follows: (~xy)= ta =

(4)

where: x = X, - ~

(5)

y = Y, - .P

(6)

and where: X i = amti ratio data point,

= average values for all (amt3 data points, Yi = corresponding rsp~ ratio data point, and = average values for all amt~ data points. Using the example ideal data set shown in Table 6, ra would be calculated as follows:

(2)

r2

where: A, = area of aromatic compound i, and A, = area of internal standard. as the y-axis versus the amount ratio amt,: amt, = IV,~ W~

Conditions 2

60mx0.25or 0.32 mm i.d., Of = 1.0 lam methylsi/icone Splitter 100:1 to 150:1 0.1-0.5 250"C

Inlector type Inlector split ratio Injection s=ze (laL) Inlector temperature (C)

9.2 G C / M S Calibration Procedure." 9.2.1 Prepare the GC/MS system according to manufacturer's instructions and set analysis operating conditions. Table 4 gives suggested operating conditions for split and on-column injection modes. 9.2.2 Before initiating the calibration procedure, tune the mass spectrometer according to manufacturer's instructions. Set the mass spectrometer data system to acquire data in the full scan (TIC-RIC) mode. 9.2.3 The WCOT must meet the resolution requirements described in 9.2.3.1 when installed in the GC/MS system. 9.2.3.1 Resolution R between 1,3,5-trimethylbenzene and 1-methyl-2-ethylbenzene at the 3 mass % level each must be equal to or greater than 4.0. R

G C / M S C o n d i t i o n s '~

.

(Zxy)~ . . (Zx2)(l~ya)

(5)(5) . (t0.0)(2.5)

1.0

(7)

9.3.4 Linear Least Squares F i t - - F o r each aromatic i calibration data set, obtain the linear least squares fit equation in the form: (rspi) = (m,)(amti) + b i,

(3)

(8)

= response ratio for aromatic I (y-axis), rni -- slope of linear equation for aromatic I, amt, = amount ratio for aromatic 1 (x-axis), and bi = y-axis intercept. The values m,. and b, are calculated as follows: rsp~

where: 147,= mass of aromatic compound i in the calibration standard, and W~ = mass of internal standard in the calibration standard. The x-axis to generate calibration curves for each aromatic component is specified in Table 1. See Fig. I for an example plot. 9.3.3 Check the correlation ta value for each aromatic

Zxy

m~ = Z---~ and 965

(9)

it~'~ D 5769 TABLE 5

TABLE 7

Mass Spectrometer Spectral Requirement For 3 mass % 1,2,3-trimethylbenzene Ion (m/e)

Relative Intensity

120 105

30-60 100

<31

Composition of Quality Control Reference Material Compound

Concentration, Weight %

n-Hexane n-Heptane n-Octane n-Decane

7-15

12 17 17 12

n-Dodecane

5

2,2,4-Trimethylpentane

12

Benzene Response

Ratio

16 -I //

/ /

1

Methylbenzene (toluene) 1,3-Dimethylbenzene 1,2-Dimethylbenzene Ethylbenzene 1,2,4-Tdmethylbenzene 1,2,4,5-Tetramethylbenzene Total aromatics

i/

9 3 3 3 3 3 25

//

12-

/

/ 10-

calibration curve forced through the origin with a resulting zero intercept value.

/ ./

~,..~..~ z - ~ n t e r c e p t t . r t t e r t a r t.allorallOrlS Curves N o t F o r c e d T h r o u g h Z e r o - - - F o r a n o p t i m u m calibration, the

// 8-

D i//

a b s o l u t e value o f the y-intercept (bi) m u s t be at a m i n i m u m , that is, A; a p p r o a c h e s zero w h e n w; is less t h a n 0.1 mass %. As A~ a p p r o a c h e s zero, the e q u a t i o n to d e t e r m i n e the mass p e r c e n t a r o m a t i c s i or w;, reduces to Eq 14.

/

6-

/

4-

//

f

u,i = (b,/m,)(Ws/We) 100 %

/' 2--

where: w, = aromatic i, mass %, W,.= mass of internal standard added to the gasoline samples for the quantitation of the aromatic component i, g, and W,= mass of gasoline samples, g. Determine the acceptability of the y-intercept of the calibration curve of each aromatic component by substituting in Eq 14 the corresponding slope (mi) and intercept (b,) along with typical (or average) values for sample mass (HI,). If the calculated mass % aromatic i ( Wi) is not less than 0.1 mass %, verify the integrity of the GC/MS system and all calibration standards and recalibrate. 9.3.6 Every effort must be made to obtain linear calibration curves to ensure optimum chromatographic performance and that the MS signal is not saturated. However, for certain components present in large concentrations in the samples, such as toluene, some nonlinearity may exist. For such compounds follow the following quantitation procedure. 9.3.6.1 Plot component concentration versus compound response factor of each calibration standard. 9.3.6.2 If the deviation of the response factors for the higher concentration standards is greater by more than 5 % relative than the response factors of the lower concentration standards which are in the linear range, then use a linear fit tbr all calibration points. 9.3.6.3 If the deviation in 9.3.6.2 is in the range of 5 to 10 % relative, use a quadratic fit. 9.3.6.4 If the deviation in 9.3.6.2 is greater than I0 % relative, no samples can be analyzed until the deviation is corrected. 9.3.7 The GC/MS system must be recalibrated whenever results of the quality control reference material do not agree within the tolerance levels specified in 10.1.

0

1

2 Amount

Resp Ratzo r 3 lle~000 C o r r C o e f = 0 999

FIG. 1

3 Ratlo

4

5

* Amt C u r v e Fit. L i n e a r / ( 0 , 0 )

Calibration Curve for Methylbenzene (Toluene)

b,= ~-

m,/

(10)

For the example in Table 6: m, = 5/10 = 0.5

(11)

and h, = 1.5 - ( 0 , 5 ) ( 3 )

= 0

(12)

Therefore, the least square equation for the above example in Table 6 is: (13)

(r.w,) = 0.5(amt,) + 0

NOTE 6--Normally the b i term is not zero and may be positive or negative. It may be more appropriate to force the calibration through the zero intercept, that is, b, = 0, to prevent calculating negative results for components present in the samples at very low concentrations, such as the uncalibrated components. Software is available on commercial GC/MS systems for performing this. Figure 1 is an example of a TABLE 6

Sum Average

Example of Data Set for r~ Calculation

X,

YI

x = XI - £

1.0 2.0 3.0 4.0 5.0 15.0 3.0

0.5 1.0 1.5 2.0 2,5 7.5 1.5 (~

-2.0 -1.0 O,0 1.0 2.0 0.0

y= Y,-.F

xy

x2

y2

-1.0 -0.5 0.0 05 1.0 0.0

2.0 0.5 0.0 0.5 2.0 5.0

4.0 1.0 0.0 1.0 4.0 10.0

1.0 0.25 0.0 0,25 1.0 2.5

(14)

i

966

D 5769 10. Quality Control Reference Material 10.1 After the calibration has been completed, prepare the quality control reference material outlined in Table 7. Analyze the reference material as described in Sections 11 through 13. The individual aromatic and total aromatics values obtained must agree within +5 % relative of the values in the prepared reference material (for example, benzene 1.0 _+ 0.05). If the individual values are outside the specified range, verify calibration and instrumental parameters, including linearity of injection port splitter (both in concentration and boiling point) for calibration solutions, linearity of mass spectrometer response, purity of reagents, stability or repeatability of GC/MS system, accuracy of the preparation of quality control reference material, etc. DO NOT analyze samples without meeting the quality control specifications. 10.2 If samples containing oxygenated fuel additives such as ethanol or methyl-t-butylether (MTBE) are to be analyzed in addition to conventional oxygenates-free gasolines, then several quality control reference materials must be prepared containing the major oxygenated additives at levels found in gasolines to demonstrate that the injection/chromatographic performance is independent of sample types. 10.3 If the linear least squares calibration does not yield results that meet the +5 % specification for the reference material above, then try forcing the calibration through the origin, that is, bt = 0, using the GC/MS quantitation software and recalculate the results for the reference material. For components present in high concentrations, such as toluene, try using a quadratic fit as described in 8.3.6. If the results for the reference material are still in error, verify the calibration and instrument set-up. 10.4 Analyze the quality control reference materials before every batch of samples. Bracket the samples with the reference material. If the reference material does not meet the specification in 10.1, the samples analyzed immediately preceding the reference material are considered suspect and should be rerun. Retuning of the mass spectrometer and drift with time may require recalibration of the GC/MS system (see Section 9). 10.5 In addition to the analysis of the QC sample in Table 7, it is strongly recommended that a gasoline reference material be analyzed as part of the QC program. Such a reference material may be available in the future from commercial vendors or the National Institute of Standards and Technology (NIST). The round robin conducted for this test method included such a reference material to set up the instrumentation.

weighed into the samples, d8-Toluene may be used as the internal standard for toluene.

11.2 The amount of internal standards added must be approximately in the same proportion as that added to the calibration solutions. For example, if 2 g of benzene-d6 was added per 100-mL solutions for calibrations, then add 0.2 g for 10 mL of sample. The sample solution is then mixed 30 s on a vortex mixer and analyzed by GC/MS as described above.

12. Sample Analyses Procedure 12.1 Ensure that the GC/MS operating conditions are identical to those used for calibration and the system is properly calibrated and all of the criteria in Sections 9 and l0 are met. 12.2 Transfer a sufficient quantity of the chilled sample containing the appropriate internal standards from Section 11 to fill a GC autosampler vial and seal with a leak free septum cap. 12.3 Place the sample vial on the autosampler and start the analysis. 13. Calculation

13.1 Mass Concentration of Aromatic Hydrocarbon: 13.1. I Calibrated Aromatic Components (3.1.8)--Identify the various aromatic components in Table 1 from their retention times and mass spectrum. To identify a compound obtain a RIC for the primary ion (molecular ion used for quantitation) and the two other major secondary ions listed in Table 8. The criteria below must be met for a qualitative identification: 13.1.1.1 The three characteristic ions for the compound must be found to maximize in the same or within one spectrum or scan of each other. 13.1.1.2 The ratio of the intensities of the three characteristic ions for the compound must agree within +_20 % with the ratios of the relative intensities for these ions of the same TABLE 8

Mass Spec Qualitative Ions for Calibrated Sample Components

Compound Benzene Methylbenzene Ethy|benzene 1,3-Dimethylbenzene 1,4-Dimethylbenzene 1,2-Dimethylbenzene (1-Methylethyl)-benzene Propyl-benzene 1-Methyl-3-Ethylbenzene 1-Methyl-4-Ethylbenzene 1,3,5-Trimethylbenzene 1-Methyl-2-Ethylbenzene 1,2,4-Trimethylbenzene 1,2,3-Trimethylbenzene Indan 1,4-Diethylbenzene Butylbenzene 1,2-Diethylbenzene 1,2,4,5-Tetramethylbenzene 1,2,3,5-Tetramethylbenzene Pentamethylbenzene

11. Sample Preparation Procedure 11.1 Tare a leak proof sample container (volumetric flask or septum sealed vial). Transfer approximately I0 g of chilled sample and record its weight ( l,Vg) to nearest 0.1 mg. Add a quantity (Ws) of benzene-d6, ethylbenzene-dl0 and naphthalene-d8 internal standards. Tare the container for each addition, starting with the least volatile internal standard. Record the weights of each internal standard to nearest 0. l mg.

Naphthalene 2-Methyl-Naphthalene 1-Methyl-Naphthalene

NOTE 7 - - T h e internal standards may be gravimetrically pre-mixed into a larger stock solution and then added as a single addition and

967

Primary Ion 78 91 106 106 106 106 120 120 120 120 120 120 120 120 117 134 134 134 134 134 148 128 142 142

Secondary Ion Secondary Ion 2 3 77 92 91 91 91 91 105 91 105 105 105 105 105 105 118 105 120 105 120 120 133 127 141 141

79 89 77 105 105 105 77 92 91 91 119 91 119 119 115 91 91 91 91 91 91 102 115 115

1t~ D 5 7 6 9

13.1.3.2 Mass 91--Use to quantitate toluene from its calibration curve. Ignore any other mass 91 peaks. 13.1.3.3 Mass 106--Use to quantitate ethylbenzene and the three xylene isomers from their respective calibrations. 1,3-dimethylbenzene and 1,4-dimethylbenzene may be unresolved or poorly resolved. Ignore any other mass 106 peaks. 13.1.3.4 Mass 120--Use to quantitate C9--benzenes using their respective calibration curves. Ignore any other mass 120 peaks. 13.1.3.5 Mass 134--Use to quantitate Cl0--benzenes. Assume all mass 134 response up to the retention time of 1,2,3,4-tetramethylbenzene are Cl0--benzenes. For calibrated components use their corresponding calibration curves. For uncalibrated components, use the calibration curve of 1,2,3,5-tetramethylbenzene. 13.1.3.6 Mass 117--Use to quantitate indan and substituted alkylindans. Assume all mass 117 peak eluting after indan are substituted alkyl indans. Use the calibration curve for indan to quantitate all mass 117 peaks. 13. i.3.7 Mass 148--Use to quantitate CI 1 benzenes. Use

compound in the calibration analyses. 13.1.1.3 The retention time at the maximum intensity scan of 13.1.1.1 must be within +30 s of the retention time of the authentic compound from the calibration analyses. 13.1.2 Uncalibrated Aromatic Components (3.1.9)--The calibration components in Table 1 may not account for all of the aromatic hydrocarbons present in the gasoline sample. Uncalibrated aromatics are identified by the existence of peaks with characteristic ions in specified retention time ranges (see Fig. 2). The concentration of the uncalibrated components is estimated using the calibration curves of several of the calibrated components (13.1.3). 13.1.3 After the compounds in Table 1 have been properly identified, measure the areas of each peak at the specified primary quantitation mass and that of the internal standards using the same procedure used for the calibration solutions. Using the sample RIC plots in Fig. 2, follow the steps below for quantitation. 13.1.3.1 Mass 78--Use to quantitate benzene from its calibration curve. Ignore any other mass 78 peaks. ~bundance

ION 78

100OO00 800000 600000 400000.

BENZENE

200000 0 Pime--> %bundance

'

'

'

'

I

'

'

12.00

'

'

I

"

'

'

'

I

'

14,00 16,00

'

'

'

I '''';'''

'

I

'

'

'

'

i

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'

18,00 20,00 22,00

'

I

'

'

'

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I

'

'

'

'

i

'

'

24,00 26,00 28,00

'

ION 91

1000000 800000. M E T H Y L B E N Z E N E

(TOLUENE)

600000400000 200000 0 ~ime--> Abundance

. . . .

I

'

'

'

'

1

12.00

. . . .

14.00

f

. . . .

16.00

I ' ' ' ' I ' ' ' ' I .... I ' '~' "1 ' ' ' ' I .... 18. O0 2 0 . 0 0 2 2 . 0 0 2 4 . 0 0 2 6 . 0 0 28 . 0 0 .i

ION 106 1000000

800000 600000

4O0O00

~

200000 ?ime-->

0

i

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"

A '

' ' '

I

'

12.00

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l

'

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I ' ' '

14,00 16,00

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18,00 20,00 22,00

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'

J

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A '

' '

I

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24,00 26,00 28,00

'

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'

MINUTES FIG. 2a

Reconstructed Ion Chromatograms (RIC) for m/e 78 (Benzene), 91 (Methylbenzene) and 106 (C-8 Aromatics)

968

(@) D 5769 Abundance

ION 120 250000" 1-METHYL-3-ETHYLBENZENE 2 0 0 00 0 •

z

I-METHYL-4.ETHYLBENZE N E

L

,.

150000.

50000.

~ "~

-~ z uJ m ..J >'r ~-

uJ z w N Z ,,,

,

UJ

U.I

I~

--

.J

-

>-

w Z N

LIJ z

-J

W,

"<

w _i

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z N

~

~

-~

~ Pime-->

32.00

34.00

~

uJ z tu N z

~

- -

= ~

M v-"

J "

AIgl // 36.0~

L. 3--8:00

ll

.

4__0_.00

A 42.00

44.00

%bundan~e

70000

ION

[

134

l

1,4-DIETHYLBENZENE BUTYLBENZENE

uJ

60000

~ Zm

z

~/)

N

.J

>-

50000

r~

~>"

~~"

IxI "J >.

40000

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30000

~

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~

m

G~

zoooo. 0 ~" ' / ~

'

r i m e - - ~ o . O0 ' ' 4 ' 2 .~0 0

' ' 4'4.00

~

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"~

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"~

' ' 5'0.00

.,,

' /X~ ' 5'2.00

't"

~,

' ' 5'4.00

MINUTES FIG. 2b

Reconstructed

Ion C h r o m a t o g r a m s

(RIC) for m / e (C-9 A r o m a t i c s ) a n d 134 ( C - 1 0 A r o m a t i c s )

calibration curve of pentamethylbenzene for quantitation of all detected components with mass 148. 13.1.3.8 Mass 1 6 2 - - U s e to quantitate C 12 benzenes. The concentrations of these components may be at or below detection limits. If detected, use calibration curve of pentamethyl benzene for quantitation. 13.1.3.9 Mass 1 2 8 - - U s e to quantitate naphthalene from its calibration curve. Ignore all other mass 128 peaks. 13.1.3.10 Mass 1 4 2 - - U s e to quantitate the two methylnaphthalene isomers from their corresponding calibration curves. Ignore all other mass 142 peaks.

13.1.4.1 If the calibration curves were obtained by forcing the intercept to be zero then b; = 0. 13.1.4.2 For components that yielded nonlinear calibrations as specified in 9.3.6 calculate IV, using appropriate software provided with the GC/MS system. 13.1.5 For the uncalibrated component, either sum all of their peak areas and treat the total area as a single component for quantitation or treat each uncalibrated component as a single component for quantitation and then sum their total concentrations.

NOTE 8--For the quantitation of the uncalibrated components, DO NOT include the peak areas of any calibrated components having a similar reconstructed (RIC) ion response with the summed areas of the uncalibrated components. The calibrated components are quantitated separately using their respective calibrations.

NOTE 9--It may be more appropriate to force the calibration curves used to quantitate the uncalibrated components through the zero intercept, that is, b, = 0, to prevent calculating negative results for the uncalibrated components that are present in the samples at very low concentrations.

13.1.4 From the linear least squares fit calibrations, Eq 15, calculate the absolute mass of each aromatic (IV,) in grams in the gasoline samples using the response ratio (rsp,) of the areas for the sample of the aromatic component to that of the internal standard as follows:

13.1.6 To obtain mass percent'(wi) results for each aromatic hydrocarbon, including uncalibrated aromatics: wI = ( W~/Wg)(IO0 %)

969

(16)

II~

D 5769

~bundanc~ 140000

ION 117

120000

INDAN

IOO000 80000 60000

UNCALIBRATED

INDANS

40000

20000 0 ' rime--~o.oo

'

'

'

I

'

'

'

45. O0

I

'

'

'

'

50. O0

'

)

'

'

55. O0

'

I

'

i

i

'%

"1"

J

i

~'

i

65.00

60. O0

~fiundance 60000

ION 148 uJ Z w

40000 UNCALIBRATED

.i m ..I

C11-BENZENES(ALL)

20000

o

.. . ... . ... . ... . ...

rime--::60.00

52.00

A 54.00

56.00

. -. ' r. . .'^'. .,' ..' . , 58.00

60.00

.~.,,..,.A..~:_r..,.,...,, 62.00

64.00

66.00

, . .'

68.00

MINUTES FIG. 2c

Reconstructed Ion Chromatograms (RIC) for role 117 (Indans) and 148 (C-11 Aromatics)

where: Wx= mass of gasoline sample. 13.1.7 To obtain the mass % of the total aromatic concentration w,, sum the mass % of each aromatic component, including the mass % of the uncalibrated components: w, = Zw,

(17)

13.1.8 Report results to nearest 0.01 mass %. 13.2 Volumetric Concentration of Aromatics: 13.2.1 If the volumetric concentration of each aromatic component is desired, calculate the volumetric concentration according to Eq 18:

v, = w,{O//D,)

(18)

13.2.3 Report results to nearest 0.01 volume %. 14. Precision and Bias s 14.1 Precision--The precision of this test method as determined by a statistical examination of interlaboratory results are as follows: 14.1.1 Repeatability--The difference between successive results obtained by the same operator with the same apparatus under constant operating conditions on identical test materials would, in the long run, in the normal and correct operation of the test method exceed the following values only in one case in twenty: Volume benzene toluene total aromatics

0.059(20 O.061(X + 1.3) 0.027(X + 4.4)

Mass 0.052(20 0.088(20 0.025(X + 7,3)

where: v, = volume % of each aromatic to be determined, D, = relative density at 60*F (15.56"C) of the individual aromatics as found in Table 2, and Dy = relative density of the fuel under study as determined by Test Methods D 1298 or D 4052. 13.2.2 To obtain the volume percent of the total aromatic concentration Vt, sum the volume % of each aromatic component, including the volume percent of the uncalibrated components:

where X is the mean mass or volume % of the component. 14.1.2 Reproducibility--The difference between two single and independent results obtained by different operators working in different laboratories on identical test materials would, in the long run, in the normal and correct operation of the test method exceed the following values only in one case in twenty:

(19)

For the volume % precision for total aromatics and benzene, constant density values tbr the round-robin samples were provided to the round-robin participants.

VI = ~ V !

970

~

D 5769

~,bundance

50000

ION 128

40 0 0 0

NAPHTHALENE

30000

20000

i0000 i

o

~ime-->50.O0 Abundance

~.~,'-., 52.00

-~.~-

54.00

56,00

,,,~--~' 58.00

60.00

.... ~,

62.00

~',

64.00

66.00

68.00

ION 142

50000

40000 2-METHYL-NAPHTHALENE 30000

20000 1-METHYL-NAPHTHALENE

A

lO000

,

Pime--~O.O0

52.00

54.00

56.00

i

58.00

J

60.00

.t

62.00

,

i

,~JL~',',,', ,', ',,~

64.00

66.00

68.00

MINUTES FIG. 2d

benzene toluene total aromatics

Reconstructed Ion Chromatograms (RIC) for m/e 128 (Naphthalene) and 142 (MethyI-Napthalenes) Volume

Mass

0.11(X) 0.14(X + 1,3) 0.10(X + 4.4)

0.11(X) 0.17(X) 0.091(X + 7.3)

suitable for determining the bias for the procedures in this test method bias cannot be determined.

15. Keywords

where X is the mean mass or volume % of the component. 14.2 Bias--Since there is no certified reference material

15.1 aromatics; benzene; GC/MS; gasolines; gas chromatography; mass spectrometry; toluene

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and ff not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 100 Barr Harbor Drive, West Conshohocken, PA 19428.

971

(~l~

Designation: D 577e - 95 Standard Test Method for Bromine Index of Aromatic Hydrocarbons by Electrometric Titration 1 This standard is issued under the fixed designation D 5776; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (~) indicates an editorial change since the last revision or reapproval.

3.1.1 bromine index--the number of milligrams of bromine consumed by 100 g of sample under given conditions.

1. Scope 1.1 This test method determines the amount of brominereactive material in aromatic hydrocarbons and is thus a measure of trace amounts of unsaturates in these materials. It is applicable to materials having bromine indexes below 500. 1.2 This test method is applicable to aromatic hydrocarbons containing no more than trace amounts of olefins and that are substantially free from material lighter than isobutane and have a distillation end point under 288"C (550"F). 1.3 The following applies to all specified limits in this standard: For purposes of determining conformance with this standard, an observed value shall be rounded off "to the nearest unit" in the last right hand digit used in expressing the specification limit, in accordance with the rounding off method of Practice E 29. 1.4 This standard does not purport to address all of the safi,ly concerns, if any, associated with its use. It is the re37)onsibility of the user of this standard to establish appropriate saJety and health practices and determine the applicability of regulatory limitations prior to use. For a specific hazard statement see Section 8.

4. Summary of Test Method 4.1 The specimen dissolved in a specified solvent is titrated with standard bromide-bromate solution. The end point is indicated by a fixed end-point electrometric titration apparatus, when the presence of free bromine causes a sudden change in the polarization voltage of the system. 5. Significance and Use 5.1 This test method is suitable for setting specification, for use as an internal quality control tool, and for use in development or research work on industrial aromatic hydrocarbons and related material. This test method gives a broad indication of olefinic content. It does not differentiate between the types of aliphatic unsaturation. 6. Apparatus 6.1 Fixed End Point Electrometric Titration Apparatus-Any fixed end-point apparatus may be used incorporating a high resistance polarizing current supply capable of maintaining approximately 10 to 50 ~tA across two platinum plate electrodes or a combination platinum electrode and with a sensitivity such that a voltage change of approximately 50 mV at these electrodes is sufficient to indicate the end point (see Note 1).

2. Referenced Documents

2.1 ASTM Standards." D 1193 Specification for Reagent Water 2 D 1159 Test Method for Bromine Number of Petroleum Distillates and Commercial Aliphatic Olefins by Electrometric Titration 3 D 3437 Practice for Sampling and Handling Liquid Cyclic Products 4 E 29 Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications5 2.2 Other Document: OSHA Regulations, 29 CFR paragraphs 1910.1000 and 1910.12006

NOTE l--The reagents and techniques may be checked by determining the bromine index of a 100 mg/kg cyclohexenein heptane. This is expected to give a bromine index of 180 to 200 mg/100 g sample. Refer to Table A2.1 of Test Method D 1159. 6.2 Titration Vessel--A tall form glass beaker of approximately 250-mL capacity or a water jacketed titration vessel of approximately 250-mL capacity connected to a refrigerated circulating water bath controlling the temperature at 0 to 5"C. A pair of platinum electrodes spaced not more than 5 mm apart, shall be mounted to extend well below the liquid level. Stirring shall be by a mechanical or electromagnetic stirrer and shall be rapid but not so vigorous as to draw air bubbles down to the electrodes. 6.3 Iodine Number Flasks, glass-stoppered, 500-mL capacity.

3. Terminology 3.1 Definition: This test method is under the jurisdiction of ASTM Committee D-16 on Aromatic Hydrocarbons and Related Chemicals and is the direct responsibility of Subcommittee D I6.0E on Instrumental Analysis. Current edition approved Sept. 15, 1995. Published November 1995. 2 Annual Book of ASTM Standards, Vol I 1.01. 3 Annual Book of ASTM Standards, Vol 05.01. 4 Annual Book of ASTM Standards, Vol 06.04. 5 Annual Book of ASTM Standards, Vol 14.02. 6 Available from Superintendent of Documents U.S. Government Printing Office, Washington, DC 20402.

7. Reagents and Materials 7.1 Purity of Reagents--Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents shall conform to the specifications of the American Chemical Society where such specifications are 972

~@) D 5776 TABLE 1

available. 7 Other grades may be used, providing it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination. 7.2 Purity of Water--Unless otherwise indicated references to water shall be understood to mean reagent water conforming to Type III of Specification D 1193. 7.3 Bromide-Bromate Standard Solution (0.10 N)S--Dissolve 10.1 g of potassium bromide (KBr) and 2.8 g potassium bromate (KBrO3) in water and dilute to 1.0 L. Standardize to four significant figures as follows: Place 50 mL of glacial acetic acid and 1.0 mL of concentrated hydrochloric acid (HCI, sp gr 1.19) in a 500-mL iodine number flask. Chill the solution in an ice bath for approximately 10 min and with constant swirling of the flask, add from a 50-mL buret 40 to 45 mL of bromide bromate solution, estimated to the nearest 0.01 mL, at a rate such that the addition takes between 90 and 120 s. Stopper the flask immediately, shake the contents, place it again in the ice bath, and add 5.0 mL of potassium iodide (KI) solution in the lip of the flask. After 5 min remove the flask from the ice bath and allow the KI solution to flow into the flask by slowly removing the stopper. Shake vigorously, add 100 mL of water in such a manner as to rinse the stopper, lip, and walls of flask, and titrate promptly with the standard sodium thiosulphate (Na2S203) solution. Near the end of the titration add 1 mL of starch indicator solution and titrate slowly to the disappearance of the blue color. 7.4 Electronic Standardization of Bromide-Bromate Solulion--Standardize to four significant figures as follows: Place 50 mL of glacial acetic acid and 1.0 mL of concentrated hydrochloric acid (HCI, sp gr 1.19) in a 500-mL iodine number flask. Chill the solution in an ice bath for approximately 10 rain with constant swirling of the flask, add 4.00 mL of bromide bromate solution from the auto buret. Stopper the flask immediately and, shake the contents, then cool it in a ice bath for 5 min. Add 4.0 mL of potassium iodide (KI) to the lip of the flask, remove the flask from the ice bath and allow the KI solution to slowly flow into the flask by removing the stopper. Shake vigorously, transfer to a chilled beaker and rinse the flask including stopper with 100 mL of water. Immerse the electrodes into the solution, titrate with standard sodium thiosulphate (Na2S203) to an end point indicated by a significant change in potential that persists for 30 s (see Note 3).

Bromine Index 0 to 20 20 to 100 100 to 200 200 to 500

Sample Size Sample Size, g 50 30 to 40 20 to 30 8 to 10

7.6 Sodium Thiosulphate, Standard Solution (0.10 N)-Dissolve 25.0 g of sodium thiosulphate pentahydrate (Na2S203.5H20) in water and add 0.02 g of sodium carbonate (Na2CO3) to stabilize the solution. Dilute to 1.0 L and mix thoroughly by shaking. Standardize by any accepted procedure that determines the normality with an error not greater than +0.0002. Restandardize at intervals frequent enough to detect changes of 0.0005 in normality. 7.7 Starch Solution9--Mill 5 g of arrow-root starch with 3 to 5 mL of water. Add the suspension to 2 L of boiling water. As a preservative, 5 to 10 mg of mercuric iodide (HgI2) or 0.2 g of salicylic acid can also be added. Boil for 5 to 10 min, then allow to cool and decant the clear supernatant liquid into glass stoppered bottles. 7.8 Sulphuric Acid (1 + 5)mCarefully add 1 volume of concentrated sulphuric acid (H2SO4 sp gr 1.84) to 5 volumes of water and thoroughly mix. 7.9 Acetic Acid, glacial. 7.10 1-Methyl-2-Pyrrolidinone. 7.11 Titration Solvent--Prepare 1 L of titration solvent by mixing the following volumes of materials: 714 mL of glacial acetic acid, 134 mL of l-Methyl-2-Pyrrolidinone, 134 mL of methanol and 18 mL of H2SO 4 (1 + 5). 8. Hazards 8.1 Consult current OSHA regulations, suppliers' Material Safety Data Sheets, and local regulations for all materials used in this test method. 9. Sampling 9.1 Sample the material in accordance with Practice D 3437. 10. Procedure 10.1 Switch on the titrator and allow the electrical circuits to stabilize according to the manufacturer's instructions. 10.2 Introduce 150 mL of titration solvent into the titration vessel and pipet or weigh in a quantity of sample as indicated in Table l (Note 4). The sample must be completely dissolved in the titration solvent. Switch on the stirrer and adjust to a rapid stirring rate, but avoid any tendency for air bubbles to be drawn down into the solution.

NOTE 3--With commercial titrators, a sudden change in potential is indicated on the meter or dial of the instrument as the endpoint is approached. When this change persists for 30 s it marks the end of the titration. With each instrument, the manufacturer's instructions should be followedto achieve the sensitivityachieved in the platinum electrode circuit.

NOTE 4 - - F r e q u e n t l y the order o f m a g n i t u d e o f the b r o m i n e index of

a sample is unknown. In this case, a trial test is recommended using an 8 to 10-g sample in order to obtain the approximate magnitude of the bromine index. This exploratory test should be followed with another determination using the appropriate sample size as indicated in Table I. The sample mass may be determined by obtaining the density of the sample and calculating the mass of a measured volume.

7.5 Potassium Iodide Solution (150 g/L}--Dissolve 150 g of potassium iodide (KI) in water and dilute to 1.0 L. 7 Reagent Chemicals, American Chemtcal Socwty Specificattons, American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed by the American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville, MD. a The 0.10 N bromide-bromate standard solution is available corhmercially from laboratory chemical suppliers.

10.3 Start the titration with the bromide-bromate solution according to the optimized instrument conditions. Continue 9 Arrow-root starch indicator solution may also be purchased prepared from chemical suppliers.

973

(@) D 5776 7990 = molecular weight of bromine x 100.

the titration until a significant change in potential persisting for 30 s marks the endpoint of the titration. 10.4 Blanks--Make duplicate blank titrations on each batch of titration solvent and reagents. Make sure that less than O. 10 mL of bromide-bromate solution is required.

12. Report 12.1 Report the following information: 12.l.1 Bromine index to the nearest 0.5 mg/100 g.

11. Calculations 11.1 Calculate the normality of the bromide-bromate solution as follow: N I = A2N2/A

I

13. Precision and Bias 13.1 Precision--Based on limited information (32 analysis by one operator) from one laboratory, the absolute standard deviation of 0.24 at the 2.8 mg/100 g bromine index level was obtained.

(1)

where: N~ = normality of the bromide-bromate solution, A, = bromide-bromate solution, mL, A2 = Na2S203 solution required for titration of the bromidebromate solution, mL, and N2 = normality of the Na2S203 solution. 11.2 Calculate the bromine index as follows: Bromine index = [(A - B)N x 7990]/W (2)

13.1.1 Intermediate Precision (formerly called Repeatability)--The 95 % repeatability limits at the 2.8 mg/100 g levels are approximately +0.7. 13.1.2 Reproducibility--The reproducibility of this test method is being determined. 13.2 Bias--Since there is no accepted reference material suitable for determining the bias of the procedure in this test method, bias has not been determined.

where: A = bromide-bromate solution required for titration of the sample, mL, B = bromide-bromate solution required for titration of the blank, mL, N = normality of bromide-bromate solution, W = sample, g, and

14. Keywords 14.1 aromatic hydrocarbons; bromine index; brominereactive; electrometric titration

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and ff not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103.

974

(~

Designation:D 5799 - 95 Standard Test Method for Determination of Peroxides in Butadiene I This standard is issued under the fixed designation D 5799; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (0 indicates an editorial change since the last revision or reapproval.

1. Scope 1.1 This procedure covers the determination of peroxides in butadiene. 1.2 This test method covers the concentrations range of l to l0 ppm by mass (ppmw) as available oxygen. 1.3 This standard does not purport to address all of the

5.4 Heating Mantle, electric for 250-mL Erlenmeyer flasks. 5.5 Microburette, 10-mL capacity, graduated in 0.02-mL divisions. 5.6 Water Bath, a thermostatically controlled liquid bath capable of maintaining a water temperature of 60 + 1°C (140 + 2*FO.

safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicab:Tity of regulatory limitations prior to use.

6. Reagents 6.1 Purity of Reagents--Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, where such specifications are available. 4 Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination. 6.2 Purity of Water--Unless otherwise indicated, references to water shall be understood to mean deionized or distilled water. 6.3 Acetic Acid, 94 % by volume. Mix 60 mL of water with 940 mL of glacial acetic acid (CH3COOH). NOTE h Warning--Danger--Poisonous and corrosive. Combustible. Maybe fatalif swallowed.Causessevereburns. Harmfulif inhaled. 6.4 Carbon Dioxide, solid (dry ice).

2. Referenced Documents

2.1 ASTM Standards: D 1265 Practice for Sampling Liquefied Petroleum (LP) Gases-Manual Method2 D 3700 Practice for Containing Hydrocarbons Fluid Samples Using a Floating Piston Cylinder3 3. Summary of Test Method 3.1 A known mass of the butadiene sample is placed in a flask and evaporated. The residue is then refluxed with acetic acid and sodium iodide reagents. The peroxides react to liberate iodine which is titrated with standard sodium thiosulfate solution using visual end-point detection. Interfeting traces of iron are complexed with sodium fluoride.

NOTE 2: W a r n l n ~ m U s e gloves to avoid frostbite when handling.

4. Significance and Use 4.1 Due to the inherent danger of peroxides in butadiene, specification limits are usually set for their presence. This test method will provide values that can be used to determine the peroxide content of a sample of commercial butadiene. 4.2 Butadiene polyperoxide is a very dangerous product of the reaction between butadiene and oxygen that can occur. The peroxide has been reported to be the cause of some violent explosions in vessels that are used to store butadiene.

6.5 Potassium Dichromate Solution, Standard (O.I N)-Dissolve 2.452 g of potassium dichromate (K2Cr207) in water and dilute to 500 mL in a volumetric flask. NOTE 3: Warning--Avoid contact with eyes and skin and avoid breathing of dust. 6.6 Sodium Fluoride. 6.7 Sodium Iodide. 6.8 Sodium Thiosulfate Solution, Standard (0.1 N)-Dissolve 12.5 g of sodium thiosulfate (Na2S203 x 5H20 ) plus 0.1 g of sodium carbonate (Na2CO3) in 500 mL ofwater (the Na2CO3 is added to stabili7e the Na2S203 solution). Let this solution stand a week or more before using. Standardize against 0.1 N K2Cr207 solution. Restandardize at frequencies to detect changes of 0.0005 in normality.

5. Apparatus 5.1 Condensers, Liebig, with 24/40 standard-tapered ground-glass joint connections. 5.2 Cylinders, graduated, 100-mL capacity. 5.3 Flask, Erlenmeyer, 250-mL capacity, with 24/40 standard-tapered ground-glass connections with marking at 100 mL.

7. Sampling 7.1 Butadiene should be sampled in a metal container of a

a This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.D on Hydrocarbons for Chemical and Special Uses. Current edition approved Oct. 10, 1995. Published December 1995. 2 Annual Book of ASTM Standards, Vol 05.01. 3 Annual Book of ASTM Standards, Vol 05.02.

4 Reagent Chemicals. American Chemical Society SpecOTcations, American Chemical Society, Washington, DC. For sugsestions on the testing of reagents not listed by the American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville, MD.

975

(@) D 5799 type which ensures maximum safety and which is resistant to butadiene corrosion. The size of the container is dependent upon the number of times the test is to be performed according to this test method. Refer to Practice D 1265 or Practice D 3700 for instructions on sampling.

9. Calculation 9.1 Calculate the peroxide content as follows: ( A - B ) x N x 16000 peroxide, as 02, ppmw -W

where: A = N a 2 S 2 0 3 solution required for titration of the sample, mL, B = Na2S203 solution required for titration of the blank, mL, N = normality of the Na2S203 solution, W = sample weight, g, and 16 000 = milliequivalents of oxygen.

8. Procedure 8.1 Remove the oxygen from a 250-mL Erlenmeyer flask by adding several pellets (approximately 1 cm in size) of dry ice and allowing the CO 2 to displace the air. This will take approximately 5 min. 8.2 Record the weight to one decimal place of the sample cylinder, and then transfer approximately 100 mLs of butadiene sample from the cylinder to the 250 mL Erlenmeyer flask containing several pellets of dry ice. Reweigh the sample cylinder and record the weight of the sample as the difference of the two weights.

10. Precision and Bias s 10.1 Precision--The precision of this test method as determined by statistical examination of interlaboratory results is as follows: 10.1.1 Repeatability--The difference between two test results obtained by the same operator with the same apparatus under constant operating conditions on identical test materials would, in the long run, in the normal and correct operation of the test method, exceed the following values only in one case of twenty:

NOTE 4: Warning--Butadiene is a flammable gas under pressure. 8.3 Place the flask in a water bath at 60°C in a well ventilated hood. Allow the butadiene to evaporate while keeping an inert atmosphere above the liquid butadiene by continuing to add pellets of dry ice at intervals until all the butadiene has evaporated.

R = 1.4 ppmw

NOTE 5: Warning--Peroxides are unstable and react violently when taken to dryness. Peroxides at the levels experienced during the test method evaluation have not caused a problem, but caution needs to be exhibited in handling by the use of personal protective equipment.

10.1.2 Reproducibility--The difference between two single and independent results, obtained by different operators working in different laboratories on identical test material, would, in the long run and in the normal and correct operation of the test method, exceed the following values only in one case in twenty. R = 3.4 ppmw

8.4 Remove the flask from the water bath and allow to cool to ambient temperature. Add 50 mL of 94 % acetic acid and 0.20 + 0.02 g of sodium fluoride. Add several more pellets of dry ice to the flask and allow to stand for 5 min. 8.5 Add 6.0 + 0.2 g of sodium iodide to the flask and immediately connect to the Liebig condenser. Turn on the heating mantle and reflux the solution for 25 + 5 min. Keep the equipment away from strong light during refluxing. 8.6 At the end of the reaction period, turn off the heating mantle and remove the flask with condenser from the mantle. Immediately add 100 mL of water through the top of the condenser followed by several pellets of dry ice. 8.7 Maintaining an inert atmosphere with CO2 pellets, remove the flask from the condenser and allow to cool to ambient temperature. Cold water may be used to assist in this step. Titrate the liberated iodine with 0.1 N sodium thiosulfate until a clear endpoint is reached. 8.8 Repeat 8.4 through 8.7 for the reagent blank.

10.2 Bias--As no reliable source of butadiene polyperoxide is available, the actual bias of the test method is unknown; but published data reports that this test method determines 90 % of the polyperoxide. 6 11. Keywords 11.1 butadiene; butadiene polyperoxide; peroxide 5 Supporting data is available from ASTM Headquarters. Request RR:D02:1372. 6 For a discussion of the background for this test method, see Mayo, Hendry, Jones, and Scheatzlc, Industrialand Engineering Chemical, Product Research, Vol

7, 1968, p. 145.

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reepproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 100 Barr Harbor Drive, West Conshohocken, PA 19428.

976

~[~

Designation: D 5808 - 95

Standard Test Method for Determining Organic Chloride in Aromatic Hydrocarbons and Related Chemicals by Microcoulometry 1 This standard is issued under the fixed designation D 5808; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (~) indicates an editorial change since the last revision or reapproval.

1. Scope 1.1 This test method covers the organic chlorides in aromatic hydrocarbons, their derivatives, and related chemicals. 1.2 This test method is applicable to samples with chloride concentrations from 1 to 25 mg/kg. 1.3 This test method is preferred over Test Method D 5194 for products, such as styrene, that are polymerized by the sodium biphenyl reagent. 1.4 The following applies to all specified limits in this standard: for purposes of determining conformance with this standard, an observed value or a calculated value shall be rounded off "to the nearest unit" in the last right-hand digit used in expressing the specification limit, in accordance with the rounding-off method of Practice E 29. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements, see Note 2 and Section 9.

2. Referenced Documents 2.1 A S T M Standards: D 1193 Specification for Reagent Water2 D 3437 Practice for Sampling and Handling Liquid Cyclic Products3 D 5194 Test Method for Trace Chloride in Liquid Aromatic Hydrocarbons3 E 29 Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications 4 2.2 Other Document: OSHA Regulations--29CFR paragraphs 1910.1000 and 1910.12005

3. Terminology 3.1 Definitions: 3.1.1 dehydration tube--a chamber containing concentrated sulfuric acid that scrubs the effluent gases from combustion to remove water vapor.

3.1.2 oxidative pyrolysis--a process in which a sample is combusted in an oxygen-rich atmosphere at high temperature to break down the components of the sample into elemental oxides. 3.1.3 recovery factor--an indication of the efficiency of the measurement computed by dividing the measured value of a standard by its theoretical value. 3.1.4 reference sensor pair--detects changes in silver ion concentration. 3.1.5 test titration--a process that allows the coulometer to set the endpoint and gain values to be used for sample analysis. 3.1.6 titration parameters--various instrumental conditions that can be changed for different types of analysis. 3.1.7 working electrode (generator electrode)--an electrode consisting of an anode and a cathode separated by a salt bridge; maintains a constant silver ion concentration.

4. Summary of Test Method 4.1 A liquid specimen is injected into a combustion tube maintained at 900"C having a flowing stream of 50 % oxygen and 50 % argon carder gas. Oxidative pyrolysis converts the organic halides to hydrogen halides that then flow into a titration cell where it reacts with silver ions present in the electrolyte. The silver ion thus consumed is coulometrically replaced and the total electrical work to replace it is a measure of the organic halides in the specimen injected (see Annex A 1).

5. Significance and Use 5.1 Organic as well as inorganic chlorine compounds can prove harmful to equipment and reactions in processes involving hydrocarbons. 5.2 Maximum chloride levels are often specified for process streams and for hydrocarbon products. 5.3 Organic chloride species are potentially damaging to refinery processes. Hydrochloric acid can be produced in hydrotreating or reforming reactors and this acid accumulates in condensing regions of the refinery.

6. Interferences 6.1 Both nitrogen and sulfur interfere at concentrations greater than approximately 0.1%.

This test method is under the jurisdiction of ASTM Committee D-16 on Aromatic Hydrocarbons and Related Chemicals is the direct responsibility of Subcommittee DI6.0E on Instrumental Analysis. Current edition approved Oct. 10, 1995. Published December 1995. 2 Annual Book of ASTM Standards, Vol 11.01. 3 Annual Book of ASTM Standards, Vol 06.04. 4 Annual Book of ASTM Standards, Vol 14.02. 5 Available from Superintendent of Documents, U.S. Government Printing Office, Washington, DC 20402.

NOT~ l--To ensure reliable detectability, all sources of chloride contamination must be eliminated. 6.2 Bromides and iodides, if present, will be calculated as chlorides. However, fluorides are not detected by this test method. 977

~

D 5808

6.3 Organic chloride values of samples containing inorganic chlorides will be biased high due to partial recovery of inorganic species during combustion. Interference from inorganic species can be reduced by water washing the sample before analysis. This does not apply to water soluble samples.

used in all tests. Unless otherwise indicated, it is intended that all reagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, where such specifications are available. 7 Other grades may be used, provided that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination. 8.2 Purity of WatermUnless otherwise indicated, references to water shall be understood to mean reagent water conforming to Specification D 1193, Type II or III. 8.3 Acetic Acid (sp gr 1.05)--Glacial acetic acid (CH3COOH). 8.4 Argon or Helium, 99.9 % minimum purity required as carder gas. 8.5 Sodium Acetate, anhydrous, (NaCHaCO2), fine granular. 8.6 Cell Electrolyte Solution--Dissolve 1.35 g sodium acetate (NaCH3CO2) in 850 mL of acetic acid (CH3COOH), and dilute to 1000 mL with water.

7. Apparatus 6

7.1 Pyrolysis Furnace, which can maintain a temperature sufficient to pyrolyze the organic matrix and convert all chlorine present in the sample to hydrogen chloride. 7.2 Pyrolysis Tube, made of quartz and constructed so that when a sample is volatilized in the front of the furnace, it is swept into the pyrolysis zone by an inert gas, where it combusts when in the presence of oxygen. The inlet end of the tube must have a sample inlet port with a septum through which the sample can be injected by syringe. The inlet end must also have side arms for the introduction of oxygen and inert carder gas. The pyrolysis tube must be of ample volume, so that complete pyrolysis of the sample is ensured. 7.3 Titration Cell, containing a reference electrode, a working electrode, and a silver sensor electrode, as well as a magnetic stirrer. An inlet from the pyrolysis tube is also required.

NOTE 3 - - B u l k quantifies o f the electrolyte should be stored in a dark bottle or in a dark place and be prepared fresh at least every two weeks.

8.7 Oxygen, 99.6 % minimum purity is required as the reactant gas. 8.8 Gas Regulators, two-stage gas regulators must be used for the reactant and carder gas. 8.9 Potassium Nitrate (KN03), fine granular. 8.10 Potassium Chloride (KCI), fine granular.

NOTE 2: Caution--Excessive stirring speed will decouple the stirring bar, and cause it to rise in the titration cell and possibly damage the electrodes. A slight vortex in the cell will be adequate.

8.11 Working Electrode Solution (I0 % KNO3)--Dissolve 50 g potassium nitrate (KNO3) in 500 mL of distilled water. 8.12 Inner Chamber Reference Electrode Solution (1 M KCl)~Dissolve 7.46 g potassium chloride (KCI) in 100 mL of distilled water. 8.13 Outer Chamber Reference Electrode Solution (1 M KNO~)mDissolve 10.1 g potassium nitrate (KNO3) in 100 mL of distilled water. 8.14 Sodium Chloride (NaCl), fine granular. 8.15 Sulfuric Acid, (sp gr 1.84), (H2SO4) concentrated. 8.16 2,4,6-Trichlorophenol (TCP) (CrH30CI~), fine granular. 8.17 Methanol (MeOH) (CH3OH), 99.9 % minimum purity. 8.18 Chloride Standard Stock SolutionmWeigh accurately 0.1 g of 2,4,6-Trichlorophenol to 0. I rag. Transfer to a 500-mL volumetric flask. Dilute to the mark with methanol.

7.4 Microcouiometer, capable of measuring the potential of the sensing-reference electrode pair, and comparing this potential with a bias potential, and amplifying the difference to the working electrode pair to generate a current. The microcoulometer output voltage signal should be proportional to the generating current. 7.5 Automatic Boat Drive, having variable stops, such that the sample boat may be driven into the furnace, and stopped at various points as it enters the furnace. 7.6 Controller, with connections for the reference, working, and sensor electrodes. The controller is used for setting of operating parameters and integration of data. 7.7 Dehydration Tube, positioned at the end of the pyrolysis tube so that effluent gases are bubbled through a sulfuric acid solution, and water vapor is subsequently trapped, while all other gases are allowed to flow into the titration cell. 7.8 Gas-Tight Sampling Syringe, having a 50 ~tl capacity, capable of accurately delivering 10 to 40 ~tl of sample. 7.9 Quartz Boats.

Ci/L, mg MeOH (ppm) -- g ofTCP x 0.5386 x 103 L of MeOH where: TCP --- 2,4,6, Trichlorophenol, and MeOH = Methanol.

8. Reagents and Materials

8.1 Purity of Reagents--Reagent grade chemicals shall be 7 Reagent Chemicals, American Chemical Society Specifications, American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed by the American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the Umted States Pharmacopeia and National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville, MD.

6 Microcoulometer such as the TOX-10Z and TOX-10, manufactured by Mitsubishi Chemical Corporation, and available through Cosa Instruments, 55 Oak Street, Norwood, NJ 07648, or equivalent instrument, has been found satisfactory for this purpose.

978

o s8oa 12.4.1 Volumetric measurement can be utilized by filling the syringe with standard, carefully eliminating all bubbles, and pushing the plunger to a calibrated mark on the syringe, and recording the volume of liquid in the syringe. After injecting the standard, read the volume remaining in the syringe. The difference between the two volume readings is the volume of standard injected. This test method requires the known or measured specific gravity or density, to the third decimal place. Several densities of various hydrocarbons are listed in Table 2. A sample size of 40 lxL is suggested to start, and then this volume can be adjusted to accommodate more quickly or more accurate determinations. 12.4.2 Alternatively, the syringe may be weighed before and after the injection to determine the weight of sample injected. This technique provides greater precision than the volume delivery method, provided a balance with a precision of ± 0.0001 g is used. 12.5 Insert the syringe needle through the septum and into the quartz boat inside the boat drive. Start the boat drive, and insert the standard into the pyrolysis furnace. 12.6 Repeat the measurement of each calibration standard at least three times. 12.7 If a low recovery factor (less than 95 %) occurs, prepare fresh standards. If the recovery factor remains low, prepare new electrolyte, or new electrode solutions, or both. If the recovery factor still does not fall in the proper range, review the procedural details. 12.8 Calculate the three-point calibration curve.

9. Hazards 9.1 Consult the current version OSHA regulations, supplier's Material Safety Data Sheets, and local regulations for all materials used in this test method. 10. Sampling 10.1 Consult guidelines for taking samples from bulk in accordance with Practice D 3437. 11. Preparation of Apparatus 11.1 Carefully insert the quartz pyrolysis tube in the furnace and connect the oxygen and cartier gas lines. 11.2 Connect the boat drive to the pyrolysis tube and furnace. 11.3 Add the electrolyte solution to the titration cell, flushing several times. Maintain the electrolyte level at the highest marked line on the titration cell. 11.4 Add the proper solutions to the chamber of the working electrode and to the inner and outer chambers of the reference electrode. 11.5 Place the titration cell on the magnetic stirring device and connect the reference, working, and sensor electrodes to the controller. 11.6 Initiate a test titration of the titration cell according to the manufacturer's instructions. 11.7 Turn on the heating element of the pyrolysis furnace, and connect the dehydration tube to the outlet end of the pyrolysis furnace and to the cell. 11.8 Adjust the flow of the gases, the pyrolysis furnace temperature, and titration parameters to the desired operating conditions. Typical operational conditions are given in Table 1. 11.9 Prebake the sample boats to be used for the determination.

13. Procedure 13.1 Clean the syringe to be used for the sample. Flush it several times with the sample. Determine the chloride concentration in accordance with 12.4 through 12.6. 13.2 Chloride determination for the sample may require a change in titration parameters or adjustment in sample size, or both.

12. Calibration and Standardization 12.1 Using the chloride standard stock solution (see 8.18), make a series of three calibration standards covering the range of expected chloride concentration. 12.2 Into three 100-mL volumetric flasks, respectively pipet 1, 15, and 30 mL of chloride stock solution and dilute to the mark with methanol. (The standards are approximately 1 mg CI/L MeOH, 15 mg CI/L MeOH and 30 mg CI/L MeOH). 12.3 Adjust the operational parameters for a three-point calibration. If instrument is not equipped for a three-point calibration, manually record the recovery factors and calculate. 12.4 The sample s i z e can be determined either volumetrically, by syringe, or by mass. Make sure that the sample size is 80 % or less of the syringe capacity.

14. Calculation 14.1 Measurement utilizing volume and known specific gravity in milligrams per kilograms as follows: Chloride, mg/kg = ( M - B) x I-Lv x SG

14.2 Measurement utilizing weight of sample, considering dilution's in milligrams per kilograms as follows: Chloride, mg/kg = TABLE 2

TABLE 1 Parameter End Point Gain 1 Gain 2 Gain 3 Sensitivity Furnace temperature Oxygen flow Carder gas flow

(1)

RF

Operating Parameters Value 290 to 315 mV 0.5 to 5.0 1.0 to 10.0 1.0 to 15.0 0.5 to 1.5 mV 900 to 1100°C 200 mL/min 250 mL/min

(M - B) w

1 x --

(2)

RF

Densities of Common Hydrocarbons A

Component

Density

Temperature °C

Benzene Cyclohexane Ethylbenzene Isopropylbenzene Toluene m-Xylene o-Xylene

0.879 0.779 0.867 0.862 0.867 0.864 0.880

20 20 20 20 20 20 20

A Handbook of Chemistry and Physics, 40th Edition, "Table, Physical Constants of Organic Compounds', Chemical Rubber Co.

979

~) D 5808 where: M = measured chloride value, I.tg, B = blank chloride value, I.tg, v = sample injection volume, mL, w = weight of sample, g, SG = relative density, and RF = recovery factor = ~tg chlorides titrated theoretical value 15. Report 15.1 Report the chloride results as (mg/kg) of the.sample.

16. Precision and Bias s 16.1 Precision--The results from six laboratories were used to generate statistical data. Three values were recorded for each sample. The standard used to calibrate a standard curve was provided with the samples and a volume of 40 IxL was specified for all injections. For statistical calculations, the average value obtained on the neat (or blank) sample was s Supporting data are available from ASTM Headquarters. Request RR: Dl6-1017.

subtracted from the average value for the 1 mg/kg, 5 mg/kg, and 25 mg/kg samples. 16.2 Intermediate Precision--Two successive test results generated by the same laboratory, on the same sample, by the same operator, with the same test equipment should not be considered suspect unless the difference is greater than 0.7 mg/kg, with 95 % confidence. 16.3 Reproducibility--Two tests generated in different laboratories, on the same sample, should not be considered suspect unless the difference is greater than 1.3 mg/kg, with 95 % confidence. 16.4 Bias--The results from the analysis by 6 different laboratories of gravimetrically prepared standard addition samples indicated that this procedure does not contain a measurable amount of bias nor systematic error that could contribute to a difference between a population mean and the accepted true value. NOTE 4--Although the data in this report was compiled using an automatic boat drive, direct needle injections with a constant rate injector have been found to give satisfactoryresults. 17. Keywords 17.1 density; electrolysis; electrolyte; microcoulometry; potential; pyrolysis; recovery factor; relative density; titration; total chloride; volatilization

ANNEX

(Mandatory Information) AI. C O M B U S T I O N AND TITRATION M E A S U R E M E N T PRINCIPLES

A 1.1 Oxidative Pyrolysis: A 1.1.1 The sample is injected by a 50-~tL syringe, into a quartz boat, which is driven into a pyrolysis tube. Here, the sample is first volatilized, and then swept by a carrier gas further into the furnace, where it is combusted in a flow of oxygen gas. Hydrogen atoms from the breakdown of the hydrocarbon sample react with the chlorine atoms liberated by combustion to form hydrogen chloride. Hydrocarbons break down and form the following combustion products: X (CI) S

C H N p

---, --* 02 ~ ) 900"C ~ ~ --*

HX (HCI greater than C12) SO2 greater than SO3

C02

tube to remove water, and then introduced into the titration cell. AI.2 Titration: A I.2.1 Before hydrogen chloride is introduced into the cell, the electrolysis potential is kept at the end point potential, and the following equilibrium equation is maintained: Ag ¢:~ Ag + + c A l . 2 . 2 When hydrogen chloride is introduced into the cell, the following reaction takes place: HCi + Ag+ ~ AgCI + H +

AI.2.3 When the potential changes, electrolysis current is applied to the working electrode to generate silver ions. Thus, the silver ions consumed are replaced coulometrically. The total current applied is a measure of the chlorine in the sample.

H20 NO, NO2 P205

A 1.1.2 These product gases are swept into a dehydration

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend, if you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 1916 Race St., Philadelphia, PA 19103.

980

Designation: D 5842 - 95

Designation: MPMS Chapter 8.4

Standard Practice for Sampling and Handling of Fuels for Volatility Measurement 1 This standard is issued under the fixed designation D 5842; the number immediately following the designation indicates the year of original adoption or, in the ease of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (0 indicates an editorial change since the last revision or re,approval.

MPMS Chapter 8.2--Standard Practice for Automatic Sampling of Liquid Petroleum and Petroleum Products MPMS Chapter 8.3uStandard Practice for Mixing and Handling of Liquid Samples of Petroleum and Petroleum Products

1. Scope 1.1 This practice covers procedures and equipment for obtaining, mixing, and handling representative samples of volatile fuels for the purpose of testing for compliance with the standards set forth for volatility related measurements applicable to light fuels. The applicable dry vapor pressure equivalent range of this practice is 13 to 105 kPa (2 to 16 psia). 1.2 This practice is applicable to the sampling, mixing, and handling of reformulated fuels including those containing oxygenates. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safi,ty and health practices and determine the applicability of regulatory limitations prior to use. 1.4 The values stated in acceptable metric units are to be regarded as the standard except in some cases where drawings may show English measurements which are customary for that equipment.

3. Terminology 3.1 Descriptions of Terms Specific to This Standard: 3.1.1 bottom sampleua sample obtained from the material at the bottom of the tank, container, or line at its lowest point. 3.1.1.1 DiscussionmIn practice the term bottom sample has a variety of meanings. As a result, it is recommended that the exact sampling location (for example, 15 cm [6 in.] from the bottom) should be specified when using this term. 3.1.2 dead legs--sections of pipe that, by design, do not allow for the flow of material through them. 3.1.2.1 DiscussionmDead legs are not suitable for obtaining representative samples. 3.1.3 relieflinesnsections of pipe that lead to a pressure/ vacuum relief valve. 3.1.3.1 Discussion--Relief lines are not suitable for obtaining representative samples. 3.1.4 stand pipes--vertical sections of pipe or tubing extending from the gaging platform to near the bottom of tanks that are equipped with external or internal floating roofs. Stand pipes also may be found on ships and barges. 3.1.4. l Discussion--Stand pipes which are not slotted or perforated will not yield representative samples. Further information on proper stand pipe design is given in 6.4.3. 3.1.5 Other sample definitions are given in Practice D 4057.

2. Referenced Documents 2.1 A S T M Standards: D323 Test Method for Vapor Pressure of Petroleum Products (Reid Method) 2 D4057 Practice for Manual Sampling of Petroleum and Petroleum Products 3 D 4953 Test Method for Vapor Pressure of Gasoline and Gasoline-Oxygenate Blends (Dry Method) 4 D 5190 Test Method for Vapor Pressure of Petroleum Products (Automatic Method) 4 D 5191 Test Method for Vapor Pressure of Petroleum Products (Mini Method) 4 2.2 API Documents: MPMS Chapter 8--Definitions MPMS Chapter 8.1--Standard Practice for Manual Sampling of Petroleum and Petroleum Products

4. Summary of Practice 4.1 It is necessary that the samples be representative of the fuel in question. The basic principle of each sampling procedure involves obtaining a sample in such a manner and from such locations in the tank or other container that the sample will be representative of the fuel. A summary of the sampling procedures and their application is presented in Table 1. Each procedure is suitable for sampling a material under definite storage, transportation, or container conditions. The precautions required to ensure the representative character of the samples are numerous and depend upon the tank, carder, container, or line from which the sample is being obtained, the type and cleanliness of the sample container, and the sampling procedure that is to be used.

i This practice is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee I:)02.02 on Static Petroleum Measurement. Current edition approved Nov. 10, 1995. Published February 1996. 2 Annual Book of ASTM Standards, Vol 05.01. 3 Annual Book of A S T M Standards, Vol 05.02. 4 Annual Book of A S T M Standards, Vol 05.03. S Available from the American Petroleum Institute, 1220 L St., NW, Washington, DC 20005.

981

(@) D 5842 TABLE 1

Summary of Gasoline Sampling Procedures and

use the clean procedure described in 6.4. 6.3 Time and Place of Sampling." 6.3.1 Storage Tanks--When loading or discharging fuels, take samples from both shipping and receiving tanks, and from the pipelines if required. 6.3.2 Ship or Barge Tanks--Sample each product after the vessel is loaded or just before unloading. 6.3.3 Tank Cars--Sample the product after the car is loaded or just before unloading.

Applicability Type of Container

Storage tanks, ship and barge

Procedure

Paragraph

all-levelssampling

7.2.1.2

running sample upper, middle and lower

7.2.1.2 7.2.1.2

tanks, tank cars, tank trucks

samples top sample Storage tanks with taps Pipes and lines

Retail outlet and wholesale purchasar-consumar facility storage tanks

grab sampling tap sampling line sampling automatic sampling time proportional flow proportional grab sampling nozzle sampling

7.2.1.2 7.5 7.2.2 7.3 7.4 7.4.1 7.4.2 7.5 7.6

NOTE l--Time, place, and other details of sampling not covered in this practice are normally determined by contractual agreement or regulatory requirements.

5. Significance and Use 5.1 The dry vapor pressure equivalent (DVPE) of volatile motor fuels is regulated by federal and state air pollution control agencies. In order to meet the letter of these regulations, it is necessary to sample, handle, and test these products in a very precise manner. 6. General Comments

6.1 Sample Containers: 6.1.1 Sample containers are clear or brown glass bottles, fluorinated high-density polyethylene bottles, or metal cans. The clear glass bottle is advantageous because it is easily examined visually for cleanliness, and also makes visual inspection of the sample for free water or solid impurities possible. The brown glass bottle affords some protection from light. The only cans acceptable are those with the seams soldered on the exterior surface. 6.1.2 Cork stoppers, or screw caps of plastic or metal, are used for glass bottles; screw caps with inserted seals only are used for cans to provide a vapor-tight closure seal. Corks must be of good quality, clean, and free from holes and loose bits of cork. Never use rubber stoppers. Contact of the sample with the cork can be prevented by wrapping tin or aluminum foil around the cork before forcing it into the bottle. Screw caps must be protected by a cork disk faced with tin or aluminum foil, an inverted cone polyseal or other material that will not affect petroleum or petroleum products. The fluorinated bottles are supplied with polypropylene screw caps. 6.1.3 Sample size is dictated by the test method to be used. One litre (32 oz) bottles or cans are generally used for manual vapor pressure testing. The mini-vapor pressure methods need a much smaller sample and it can be taken in a 125 mL (4 oz) bottle. See Fig. 10. 6.1.4 All sample containers must be absolutely clean and free of foreign matter. Before reusing a container, wash it with strong soap solution, rinse it thoroughly with tap water, and finally with distilled water. Dry completely, stopper, or cap the container immediately. 6.2 Sampling Apparatus--Sampling apparatus is described in detail under each of the specific sampling procedures. Clean, dry, and free all sampling apparatus from any substance that might contaminate the material. If necessary, 982

6.4 ObtainingSamples: 6.4.1 Directions for sampling cannot be made explicit enough to cover all cases. Extreme care and good judgment are necessary to ensure samples that represent the general character and average condition of the material. Use lint-free wiping cloths to prevent contaminating samples. 6.4.2 Many petroleum vapors are toxic and flammable. Avoid breathing them or igniting them from an open flame or a spark. Follow all safety precautions specific to the material being sampled. 6.4.3 Do not sample dead legs or relief lines. Do not sample stand pipes that are not slotted or perforated! Figure 1 is an example of an adequately slotted stand pipe. At a minimum, the stand pipe should have two rows of slots slightly staggered in the vertical plane. 6.4.4 Rinse or flush sample containers with product and allow it to drain before drawing the sample. If the sample is to be transferred to another container (for testing other than DVPE), the sampling apparatus also is rinsed with some of the product and drained. When the sample is emptied into this container, upend the sampling apparatus into the opening of the sample container. 6.5 Handling Samples: 6.5.1 Protect all samples of light fuels from evaporation. The sampling apparatus is the sample container for vapor pressure. Keep the container tightly closed after the sample is collected. Leaking sample containers are not suitable for testing. Cool volatile samples to 0 to I*C (32 to 34"F) after delivery to the laboratory and before opening the container. Maintain at this temperature throughout transfer and handling, if at all possible. 6.5.2 Never completely fill a sample container. Fill the container to 70 to 85 % capacity to allow adequate room for

,,,,

@!i FiG. 1

Slotted Stand Pipe

~

D 5842

expansion. Subsequent testing for vapor pressure requires this level of container fill. 6.5.3 The first sample aliquot removed is for vapor pressure testing. The remaining sample in the container is not suitable for a vapor pressure determination but is suitable for other testing. 6.6 Shipping SamplesmTo prevent loss of liquid and vapors during shipment, place internal seals in the metal containers, screw the caps down tightly and check for leakage. Observe all shipping regulations applying to the transportation of flammable liquids. 6.7 Labeling Sample Containers--Label the container immediately after a sample is obtained. Use waterproof and oilproof ink or a pencil hard enough to dent the tag, since soft pencil and ordinary ink markings are subject to obliteration from moisture, product, smearing, and handling. Typical label information includes the following information: 6.7.1 Date and time (the period elapsed during continuous sampling), 6.7.2 Name of the sample (location), 6.7.3 Name or number and owner of the vessel, car, or container, 6.7.4 Brand and grade of material; and 6.7.5 Reference symbol or identification number. 6.7.6 Labeling should conform to all applicable federal, state, and local labeling regulations. 7. Specific Sampling Procedures

7.1 Sampling Procedures--The standard sampling procedures described in this practice are summarized in Table 1. Alternative sampling procedures can be used if a mutually satisfactory agreement has been reached by the party(ies) involved and such agreement has been put in writing and signed by authorized officials. 7.2 Tank Sampling." 7.2.1 Bottle Sampling--The bottle sampling procedure is applicable for sampling fuels of 105 kPa (16 psia) Reid equivalent vapor pressure or less in tank cars, tank trucks, shore tanks, ship tanks, and barge tanks. 7.2.1.1 ApparatusmA suitable sampling bottle as shown in Fig. 3 is required. Recommended diameter of the opening

/F-t" F 1 5 cm (6")

Outlet

Top sample Upper sample

Upper third

X

Middlesample

Middle third

X

Lowersample Outlet sample

Lower third

~

Clove hitch Eyelet

C:,~her Cork arrangements

1-Litre (1 qt ) Sample WeightedCage (can be fabricated to fit any size bottle)

A

B FIG. 3

Assembly for Bottle Sampling

in the boric or sample thief is 19 m m (3/4 in.). 7.2.1.2 Procedure." (a) All-levels SamplemLower the weighted, stoppered bottle (see Fig. 3) as near as possible to the draw-off level, pull out the stopper with a sharp jerk of the cord or chain and raise the bottle at a rate so that it is 70 to 85 % full as it emerges from the liquid. (b) Running Sample--Lower the stoppered container (with a hole or slot in the stopper) at a uniform rate as near as possible to the level of the bottom of the outlet connection or swing line and immediately raise the bottle to the top of the fuel at a rate of speed such that it is 70 to 85 % full when withdrawn from the liquid. NOTE 2--Running or all-level samples are not necessarily representative because the tank volume may not be proportional to the depth and because the operator may not be able to raise the sampler at the required rate. (c) Upper,Middle, and LowerSamples--Lowerthe weighted, stoppered bottle to the proper depths (Fig. 2) as follows:

Hatch

X~-~

"•-

Bottom sample NOTE--The outlet sample location shown applies only to tanks with side outlets, It does not applywhen the outletcomesfrom the floor of the tank or turns down into a sump. FIG. 2 Tank Sampling Depths

983

upper sample

middle of upper third of the tank contents

middle sample lowersample

middle of the tank contents middle of the lowerthird of the tank contents

At the selected level, pull out the stopper with a sharp jerk of the cord or chain and allow the bottle to fill completely, as evidenced by the cessation of air bubbles. When full, raise the bottle, pour offa small amount (15 to 30 %), and stopper immediately. (d) Top SamplewObtain this sample (Fig. 2) in the same manner as specified for an upper sample but at 150 mm (6 in.) below the top surface of the tank contents. (e) HandlingmCap and label bottle samples immediately after taking them, and deliver to the laboratory in the original sampling bottles. Multiple samples must be tested individually for vapor pressure. A composite sample is acceptable for other analytical tests. Inverting the sample container can aid in leak detection. Sample may be placed in ice immediately for cooling if practical (see Section 10). 7.2.2 Tap SamplingmThe tap sampling procedure is applicable for sampling liquids of 105 kPa (16 psia) DVPE,

(~

D 5842

Optional--~

Optional-~

¢111

;-..52 ¢11.~ r i l l

"//z ~./ I.t

Line o r tank wall

,i

-

Line or tank wall ------I~-~/~

ii

\

f/l,

¢'//,,

~"/z

NOTE--Probesare optional. FIG. 4

Assemblies for Tap Sampling

or less, in tanks that are equipped with suitable sampling taps or lines. This procedure is recommended for volatile stocks in tanks of the breather and balloon roof type, spheroids, floating roof tanks, and so forth. The assembly for tap sampling is shown in Fig. 4. 7.2.2.1 Apparatus: (a) Tank Taps--Equip the tank with at least three sampling taps placed equidistant throughout the tank height. A standard 1/4 in. pipe with a suitable valve is satisfactory. A sufficient number of sample taps are needed on the tank to make sampling possible at various levels. (b) Tube--Use a delivery tube that will not contaminate the product being sampled and is long enough to reach to the bottom of the sample container to allow submerged filling. (c) Tube Chiller Assembly (Optional)--If a sampling chiller is used, it is a coil of tubing immersed in an ice bath to chill a fuel sample as it is dispensed into the sample container. (d) Sample Containers--Use clean, dry glass bottles of convenient size and strength or metal containers to receive the samples. 7.2.2.2 Procedure--Before a sample is drawn, flush the sample tap and tube until approximately three times its volume has been purged. When sampling for Reid equivalent vapor pressure, the container must be chilled to a temperature as low as the material in the tank or to 0°C (32°F), whichever is greater (see sample chilling apparatus in Fig. 5). Filling the container and emptying it three times will meet this temperature requirement. Draw upper, middle, or lower samples directly from the respective taps after the flushing operation. Stopper or seal and cap, label the sample container immediately after filling and deliver it to the laboratory. 7.3 Line Sampling--The continuous sampling procedure is applicable for sampling liquids of 105 kPa (16 psia) Reid equivalent vapor pressure or less and semi-liquids in pipelines, filling lines, and transfer lines. The line sampling may be done manually or by using automatic devices. In order to take a representative sample from a line, the contents are

+~,',,,+,,,e,.."

Outlet / valve ,~ (-~ D i ':?~P°~O

i

'

To tank

va,v. •

Coppertubing~ 6 4 mmO D ) V ~

8m -

,, ,

,I

:

~

+? ~

Ou!lot~ ~

Totank Purgingvalve

Top view

I

FIG. 5

I

Cooling Bath for Reid Equivalent Vapor Pressure Sampling

mixed to ensure uniform distribution of all components and contaminants across the line. If it is necessary to condition the line, this is done four to six pipe diameters upstream of the sample point. 7.3.1 Apparatus: 7.3.1.1 Sampling Probe--The function of the sampling probe is to allow withdrawal of a representative portion of liquids. The apparatus assembly for dynamic line sampling is shown in Fig. 6. A probe is recommended for the sampling of static systems but it is not required. Probe designs that are commonly used are as follows: (a) A tube beveled at a 45" angle (Fig. 6a). (b A long-radius forged elbow or pipe bend with the end of the probe reamed to give a sharp entrance edge (Fig. 6b). (c) A closed-end tube with a round orifice spaced near the closed end (Fig. 6c). 7.3.1.2 Probe Location--The probe inlet is extended into the pipe to the center one-third of the pipeline cross-sectional area. The probe is inserted perpendicular to the direction of 984

~ End of probe closed orifice facing upstream

D 5842

2") pipe I D

~

Manufacturers standard

~T~o

1 ~ / 6 . 4 (V,¢mm-5 cm. -2") pipe ortubing

6.4 mm -5 cm (1/4"-2") pipe or tubing

diameter

valve

FIG. 6

45° bevel

11-4-(

U

m

To valve

Probes for Line Sampling

flow with the sample opening facing upstream. The sampling lines are kept as short as practicable and purged completely before any samples are taken. 7.3.1.3 Valves--To control the rate at which the sample is withdrawn, the probe or probes are fitted with ball, gate, needle, or large port valves. 7.4 Automatic Samplers--An automatic sampler includes not only the automatic sampling device that extracts the samples from the line, but also a suitable probe, connecting lines, auxiliary equipment, and a container in which the sample is collected. It must maintain sample integrity. Refer to API MPMS Chapter 8.2. Automatic samplers are classified as follows: 7.4. l Continuous Sampler, Time Cycle (Nonproportional) Type--A sampler designed so that it transfers equal increments of liquid from the pipeline to the sample container at uniform time increments. 7.4.2 Continuous Sampler, Flow-Responsive (Proportional) Type--A sampler designed to automatically adjust the sampling rate to be proportional to the flow rate of the stream. 7.4.3 Calibration--Prior to initial operation, the sample bite size must be verified to be within +5 % of the specification using an acceptable calibration procedure. Additionally, the required sample volume must be obtained during any sampling period so that the manufacturer's sampling interval is not exceeded. 7.4.4 Container--The container must be a clean, dry container of convenient size to receive the sample. All connections from the sample probe to the sample container must be free of leaks. The container is constructed in such a manner that it prevents evaporation loss. The construction must allow cleaning, interior inspection, and complete mixing of the sample prior to removal. A fixed volume type container is equipped with a pressure-relief device. 7.5 Grab or Spot Sampling--Purge approximately three volumes of product through the sample tap and tubine. Divert the sample stream to the sampling container to provide a quantity of sample that will be of sufficient size for analysis. 7.6 Nozzle Sampling--The nozzle sampling procedure is applicable for sampling light fuels from a retail type dispenser. 7.6.1 Apparatus--Sample containers conforming with Section 6 should be used. A spacer, if appropriate, and a 985

nozzle extension as shown in Figs. 7 and 8 are used when nozzle sampling. 7.6.2 Procedure--Immediately after fuel has been delivered from the pump and the pump has been reset, attach a spacer (Fig. 7), if needed, to the pump nozzle (vapor recovery type). Insert nozzle extension (Fig. 8) into the previously chilled sample container and insert the pump nozzle into the extension with slot over the air bleed hole. Fill the sample container slowly through the nozzle extension to 70 to 85 % full (Fig. 9). Remove the nozzle extension. Insert the seal and cap or stopper into the sample container at once. Check for leaks. If a leak occurs, discard the sample container and resample. If the sample container is leak tight, label the container and deliver it to the laboratory. 8. Special Precautions and Instructions 8.1 Precautions--Vapor pressures are extremely sensitive to evaporation losses and to slight changes in composition. When obtaining, storing, or handling samples, observe the necessary precautions to ensure the samples are representa-

Use this slot for leaded ~- gasolineor fuels

Use this slot for

unleadedgasoline~

////A,"

',:

/////!;--','..' +i

i [

P

: _

1

I

1'/,

+

NOTE1--Makefrom +/4in. flat non-fen'ousmetal. NOTE2--All dimensionsare in inches. NOTE3--Breakall edgesand comers. FIG. 7 Spacer for Nozzle Sampling

21

-I

1@) D 5842

Use this end ~ for leaded __J gasolineand ~

--|

--7 o,.oo0 . ~--fo~.,ea~

I

E[ I_ f

I~

/

J

IJ

1

;!~ ~ - -~~ - ' - I, '-~--)

-~l

_1

11/2'

-~

gaso,,ne

f~

=,

4

11/;~

5

NOTE 1--Use ~/4 in. Schedule 80 non-ferrous pipe. NOTE 2--All dimensions are in inches. NOTE 3--All tolerances ere + 1/1=o. A Recommend 30*. e Inside diameter schedule 80 non-ferrous pipe. FIG. 8

Extension for Nozzle Sampling

tive of the product and satisfactory for Reid equivalent vapor pressure tests. Never manually prepare composite samples for this test. Make certain that containers that are to be shipped by common carrier conform to applicable federal, state, and local regulations. When flushing or purging lines or containers, observe the pertinent regulations and precautions against fire, explosion, and other hazards. Collect all line flushes and bottle rinses for proper recovery or disposal. 8.2 Sample Containers--Use containers of sufficient strength to withstand the pressures to which they can be subjected, and of a type that will permit replacement of the cap or stopper with suitable connections for transferring the sample to the gasoline chamber of the vapor pressure apparatus.

\

sp

Nozz,e__ Nozz,._

9. Keywords NozzleWithout VaporRecovery

9.1 dry vapor pressure; fuels; gasoline; gasoline sampling; petroleum products; sampling; sample handling; sampling of volatile products; vapor pressure; volatility

FIG. 9

986

NozzleWith VaporRecovery

Assembly for Nozzle Sampling

(~lJ~ D 5842 Heightof 4 oz. bottle

•

~

I"

-

~

Tappedand threadedto fit 4 OZ. bottle n e ~

1/2" 0"~0~"

-

_J lots wi~ 3/18" radius at the top

NOTE I~AII dimensionsare in inches. NOTE 2--All decimal dimensionsrepresent minimumand maximum. NOTE 3inTolerance for all other dimensionsis + l/a=in. NOTE 4reMade of non-ferrous material, unaffected by gasoline. Scale--0.700 in. = 1 in. FIG. 10 Nozzle Extension for Nozzle Sampling with 4 oz Bottle

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the vafldity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and ff not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend, ff you fee/that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 100 Barr Harbor Drive, West Conshohocken, PA 19428.

987

(1~,) Designation: D 5845 - 95

Standard Test Method for Determination of MTBE, ETBE, TAME, DIPE, Methanol, Ethanol and tert-Butanol in Gasoline by Infrared Spectroscopy I This standard is issued under the fixed designation D 5845; the number immediately foilowin8 the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (0 indicates an editorial change since the last revision or reapproval.

oxygen-selective flame ionization detection)

1. Scope 1.1 This test method covers the determination of methanol, ethanol, tert-butanol, methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE), tert-amyl methyl ether (TAME), and diisopropyl ether (DIPE) in gasoline by infrared spectroscopy. The test method is suitable for determining methanol from 0.1 to 6 mass %, ethanol from 0.1 to 11 mass %, tert-butanol from 0.1 to 14 mass %, and DIPE, MTBE, ETBE and TAME from 0.1 to 20 mass %. 1.2 SI units of measurement are preferred and used throughout this standard. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

3. Terminology 3.1 Definitions: 3.1.1 oxygenate--an oxygen-containing organic compound, which may be used as a fuel or fuel supplement, for example, various alcohols or ethers. 3.1.2 multivariate calibration--a process for creating a calibration model in which multivariate mathematics is applied to correlate the absorbances measured for a set of calibration samples to reference component concentrations or property values for the set of samples. The resultant multivariate calibration model is applied to the analysis of spectra of unknown samples to provide an estimate of the component concentration or property values for the unknown sample.

2. Referenced Documents 2.1 A S T M Standards: D 1298 Practice for Density, Relative Density (Specific Gravity), or API Gravity of Crude Petroleum and Liquid Petroleum Products by Hydrometer Method 2 D 4052 Test Method for Density and Relative Density of Liquids by Digital Density Meter 3 D4057 Practice for Manual Sampling of Petroleum and Petroleum Products 3 D 4307 Practice for Preparation of Liquid Blends for Use as Analytical Standards 3 D 4815 Test Method for Determination of MTBE, ETBE, TAME, DIPE, tert-Amyl Alcohol, and C I to C4 Alcohols in Gasoline by Gas Chromatography 4 D 5599 Test Method for Determination of Oxygenates in Gasoline by Gas Chromatography and Oxygen Selective Flame Ionization Detector4 E 1655 Practice for Infrared, Multivariate, Quantitative Analysiss 2.2 Other Standard: GC/OFID EPA Test Method--Oxygen and Oxygenate Content Analysis6 (by way of gas chromatography with

4. Summary of Test Method 4.1 A sample of gasoline is introduced into a liquid sample cell. A beam of infrared light is imaged through the sample onto a detector, and the detector response is determined. Regions of the infrared spectrum are selected for use in the analysis by either placing highly selective bandpass filters before or after the sample or mathematically selecting the regions after the whole spectrum is obtained. A multivariate mathematical analysis is carried out which converts the detector response for the selected regions in the spectrum of an unknown to a concentration for each component. 5. Significance and Use 5.1 Alcohols and ethers are added to gasoline to produce a reformulated lower emissions gasoline. Alcohols and ethers may also be added to gasoline to increase the octane number. Type and concentration of various oxygenates are specified and regulated to ensure acceptable commercial gasoline quality. Driveability, vapor pressure, phase separation, and evaporative emissions are some of the concerns associated with oxygenated fuels. 5.2 This test method is faster, simpler, less expensive and more portable than current methods. 5.3 This test method may be applicable for quality control in the production of gasoline. 5.4 This test method is not suitable for testing for compliance with federal regulations. 6

i This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct t~sponsibility of Subcommittee D02.04.OF on Absorption Spectroscopic Methods. Current edition approved Oct. 10, 1995. Published December 1995. 2 Annual Book of A S T M Standards, Vol 05.01. 3 Annual Book of A~'TM Standards, Vol 05.02. ( Annual Book of ASTM Standards, Voi 05.03. s Annual Book of A S T M Standards, Vol 03.06. Code of Federal Regulations, Part 80 of Title 40, Section 80.46(g); also published in the Federal Register, Volume 59, No. 32, February 16, 1994, p 7828.

988

~

D 5845 to testing. This can be accomplished by storage in an appropriate ice bath or refrigerator at 0 to 5"C. 8.1.4 Do not test samples stored in leaky containers. Discard and obtain a new sample if leaks are detected. 8.1.5 Perform the oxygenate determination on fresh samples from containers that are at least 80 % full. If sample containers are less than 80 % full or have been opened and sampled multiple times, a new sample shall be obtained. 8.2 Sample Handling During Analysis: 8.2.1 Prior to the analysis of samples by infrared spectroscopy, the samples should be allowed to equilibrate to the temperature at which they should be analyzed (15 to 38"C). 8.2.2 After withdrawing the sample, reseal the container, and store the sample in an ice bath or a refrigerator at 0 to 5"C.

5.5 False positive readings for some of the samples tested in the round robin were sometimes observed. As only extreme base gasolines were tested in the round robin, no definitive statement can be made as to the expected frequency or magnitude of false positives expected in a wider range of base gasolines.

6. Apparatus

6.1 Mid-IR Spectrometric Analyzer, of one of the following types:

6.1.1 Filter-based Mid-IR Test Apparatus--The type of apparatus suitable for use in this test method minimally employs an IR source, an infrared transmission cell or a liquid attenuated total internal reflection cell, wavelength discriminating filters, a chopper wheel, a detector, an A-D converter, a microprocessor, and a sample introduction system. 6.1.2 Fourier Transform Mid-IR Test Apparatus--The type of apparatus suitable for use in this test method employs an IR source, an infrared transmission cell or a liquid attenuated total internal reflection cell, a scanning interferometer, a detector, an A-D converter, a microprocessor and a sample introduction system. 6.1.3 Dispersive Mid-IR Test Apparatus--The type of apparatus suitable for use in this test method minimally employs an IR source, an infrared transmission cell or a liquid attenuated total internal reflection cell, a wavelength dispersive element such as a grating or prism, a chopper wheel, a detector, an A-D converter, a microprocessor and a sample introduction system.

9. Preparation, Calibration, and Validation of Calibration of the Infrared Test Apparatus 9.1 Preparation--Prepare the instrument for operation in accordance with the manufacturer's instructions. 9.2 Calibration--Each instrument must be calibrated by the manufacturer or user in accordance with Practice E 1655. This practice serves as a guide for the multivariate calibration of infrared spectrometers used in determining the physical characteristics of petroleum and petrochemical products. The procedures describe treatment of the data, development of the calibration, and validation of the calibration. Note that bias and slope adjustments are specifically not recommended to improve calibration or prediction statistics for IR multivariate models. 9.3 Validation of Calibration--The calibration of the instrument must be validated in order to ensure that the instrument accurately and precisely measures each oxygenate in the presence of typical gasoline compounds or other oxygenates that, in typical concentrations, present spectral interferences. General classes of compounds that will cause interferences include aromatics, branched aliphatic hydrocarbons, and other oxygenates. 9.3.1 Preparation of Validation Standards--The minimum matrix of validation standards is presented in Table 1. Additional validation standards may be added. Prepare multicomponent validation standards of the oxygenates by mass according to Practice D 4307 or appropriately scaled for larger blends. To ensure that there is minimum interference from any oxygenate present in the base gasolines, a gas chromatographic analysis of the base gasolines must be performed to ensure the absence of oxygenates (use Test Methods D 4815, D 5599, or GC-OFID). To ensure the insensitivity of the calibration to the hydrocarbon matrix of the base gasolines, the base gasolines used for preparation of the validation standards should be different from the base gasoline(s) used for preparation of the calibration standards. To minimize the evaporation of light components, adjust the temperature of all chemicals and gasolines used to prepare standards to between 5 and 20°C. None of the samples or base gasolines used in the validation of calibration may be used for the calibration (or recalibration) of an instrument. 9.3.2 Analysis of Validation Standards--The validation standards should be analyzed by the procedure specified in Section 11. If necessary, results should be converted from

7. Reagents and Materials

7. l Standards for Calibration and Quality Control Check Solutions--Use of chemicals of at least 99 % purity is highly recommended when preparing calibration and quality control check samples. If reagents of high purity are not available, an accurate assay of the reagent must be performed using a properly calibrated GC or other techniques (for example, water determination). 7.1.1 Base gasolines containing no oxygenates, 7.1.2 Methanol, 7.1.3 Ethanol, 7.1.4 tert-Butanol, 7.1.5 Methyl tert-butyl ether, MTBE, 7.1.6 Ethyl tert-butyl ether, ETBE, 7.1.7 tert-Amyl methyl ether, TAME, and 7.1.8 Diisopropyl ether, DIPE. Note 1: Warning--These materials are flammable and may be harmful if ingestedor inhaled.

8. Sampling and Sample Handling

8.1 General Requirements: 8.1.1 Gasoline samples must be handled with meticulous care to prevent evaporative loss and composition changes. 8.1.2 Gasoline samples to be analyzed by the test method shall be obtained using method(s) specified by governmental regulatory agencies or by the procedures outlined in Practice D 4057 (or equivalent). Do not use the "Sampling by Water Displacement" method as some alcohols or ethers might be extracted into the water phase. 8.1.3 Protect samples from excessive temperatures prior 989

(1~ D 5845 TABLE 1 NOTs--All concentrations are mass %. Sample Base GasA MTBE 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36

A A A A A A A A A A A A A A A A A A B B B B B B B B B B B B B B B B B B

Minimum Matrix for Validation of Calibration TAME

ETBE

Ethanol

Methanol

t-Butanol

1.5

2

DIPE

10 5 16.5 9 18.5 12

4

1.25

17 9.5

4 6.5 3.5

3

12 6

9 7 5

16.5 10

7 6 3

3 5 1.5

3 2 7 g 6

2

5

2

14 10

1.5

2

16.5 11

4

15.5 8

5 5 3.5

3

12 8

5 6 2

16.5 9

6 4 2

3 8 1.5

1.5 4

8

1.5

,~ Bsee gasoline A should be a gasoline with at least 60 % slkylate. A suggasted recllpefor _h=___*e_ gasoline A IS 60 '/, SlO/late, 30 % U ranga reformate, and 10 "/. light straight run. Base gasoline B should be a gaanllne with at least 60 ~; ful range reforrnete. A suggested reolpe for balm gasoine B Is 60 li full range refonnete, 30 ~ FCC gasoline, and 10 "/. light straight run.

volume to mass % by the calculations described in Section 12.

9.3.3 Criteriafor l/alidation of Calibration--The calibration is considered to be validated if the following specifications are all met: 9.3.3.1 Accuracyof Each Oxygenate--Analysis of each of the oxygenates in each of the validationstandards must be within the criteria established in Table 2. If it is known that an analyte is not present in a particular validation sample, the value determined for that analyte must be less than the criteria also established in Table 2. 9.3.3.2 Overall Accuracy--The standard error of prediction (SEP) for each analyte summed over all samples in the TABLE 2

Maximum Error Allowed for Validation of Calibration

Oxygenate

MTBE TAME ETBE Ethanol Methanol t-Butenol OIPE

Error Oxygenate Is Known To Be Present, mass %, msx

1.5 2.0 1.2 0.9 0.6 0.9 1.2

validation set must be within the criteria established in Table 3. 9.3.3.3 OverallRepeatability--Each sample of the validation set must be run twice. Repeat determinations of any sample can differ by no more than 0.3 mass %. 9.3.4 Frequency of Validation--Once the calibration of the instrument has been validated, it need only be revalidated when either the instrument has been recalibrated due to repair or when the quality control check samples are outside of the test tolerance. 10. Quality Control Standards 10.1 Confirm the proper operation of the instrument each day it is used by analyzing at least one quality control TABLE 3

Error When Oxygenate Is Not

Maximum Standard Error of Prediction Allowed for Validation of Calibration

Present,mass ~;, max

Oxygenate

SEP Summed Over Samples Containing The O x y ~ t e , max

SEP Summed Over All Samples In The VaUdatkxl Set, max

0.9 1.8 1.9 0.6 0.3 0.9 0.9

MTBE TAME ETBE Ethanol Methanol t.Butanol DIPE

0.9 1.2 0.75 0.4 0.25 0.55 0.6

0.5 0.9 0.6 0.25 0.15 0.45 0.35

990

~

D 5845 TABLE 5 Pertinent Physical Constants

standard of known oxygenate content for each oxygenate to be determined. These standards should be made up by mass according to Practice D 4307 and should be at the expected concentration level for that oxygenate. The recommended quality control standard concentrations are found in Table 4. 10.2 The individual oxygenate values obtained must agree within +5 % relative of the values in the prepared quality control standard (for example, MTBE 14.0 ¢ 0.7 mass %) or to within +0.3 mass % absolute, whichever is greater (for example, methanol 4.0 ¢ 0.3 mass %). If the individual values are outside the specified range, recallbrate the instrument according to the procedures in 9.2. The quality control standards should not be used for the calibration or recalibration of the instrument. Do not analyze samples without meeting the quality control specifications.

5.41 7.77 12.5 14.9 17.2 17.2 17.2

5.76 9.26 11.0 12.8 12.8 12.8

mass % mass % mass ',~ mass ~ mass % mass ~

mass mass mass mass mass mass mass

% %

67-56-1 64-17-5 75-65-0 1634-04-4 108-20-3 637-92-3 994-.05-8

32.04 46.07 74.12 88.15 102.18 102.18 102.18

0.7963 0.7939 0.7922 0.7460 0.7300 0.7452 0.7750

Wto t = ~ [(m I X 16.0 x

Ni)/MI]

(2)

total mass % oxygen in the fuel, mass % for each oxygenate, atomic mass of oxygen, number of oxygen atoms in the oxygenate molecule, and M~ = molecular mass of the oxygenate molecule as given in Table 5. 13. Report 13.1 Report results of each oxygenate and the total oxygen to the nearest 0.1 mass %.

14. Precision and Bias7 14.1 The precision of the method as obtained by statistical examination of interlaboratory results is as follows: 14.2 Repeatability---T~e difference between successive test results, obtained by the same operator with the same apparatus under constant operating conditions on identical test material would, in the long run, in the normal and correct operation of the test method exceed the following values only in one case in twenty: Oxygenate MTBE TAME ETBE Ethanol Methanol t-Butanol DIPE Total Oxygen Content

Concentration to Attaln

4.00 mass %

Methanol Ethanol

where: Wto, = m~ = 16.0 = N~ =

TABLE 4 Recommended Concentrations for Individual Quality Control Standards

Methanol Ethanol tort-Butanol MTBE TAME DIPE ETBE

Relative Density, 15.56"C

D~. = relative density at 15.56°C of the individual oxygenate as found in Table 5, Df = relative density of the fuel at 15.56°C under study as determined by Practice D 1298 or Test Method D 4052. If the density has not been measured, an assumed density of 0.742 should be used. 12.2 Total Mass % Oxygen--To determine the total oxygen content of the fuel, sum the mass % oxygen contents of all oxygenate components determined above according to Eq 2:

:

2.7 mass % O

Molecular Mass

MTBE DIPE ETBE TAME

12. Calculation 12.1 Conversion to Mass Concentration of Oxygenates--If the instrument readings are in volume % for each component, convert the results to mass % according to Eq 1: m: VI (Dl/Dy) (1) where: m~ = mass % for each oxygenate to be determined, V,. = volume % of each oxygenate,

2.0 mass % O

GAS Number

tort-Butanol

11. Procedure 11.1 Equilibrate the samples to between 15 and 38°C before analysis. 11.2 Follow the manufacturer's instructions for estabfishing a baseline for the instrument, introducing a sample into the sample cell and operating the instrument. If the instructions call for a non-oxygenated gasoline to be used in establishing the baseline, use a non-oxygenated gasoline that is different from the non-oxygenated gasolines used in the preparation of either calibration standards, validation of calibration standards, or quality control standards. 11.3 Thoroughly clean the sample cell by introducing enough sample to the cell to ensure the cell is washed a minimum of three times with the test solution. 11.4 Establish that the equipment is running properly by running the quality control standards prior to the analysis of unknown test samples (see Section 10). 11.5 Introduce the sample in the manner established by the manufacturer. Obtain the concentration reading produced by the instrument.

Oxygenate

Component

Repeatability (mass %) 0.13 0.13 0.15 O.13 0.07 O.! 0 0.14 0.05

14.3 Reproducibility--The difference between two single and independent results, obtained by different operators working in different laboratories on identical test materials would, in the long run, exceed the following values only in one case in twenty:

3.5 mass ~ O 10.1 mass %

Y. %

7 Supporting data available from ASTM Headquarters. Request D02-1374.

991

~ Oxygenate MTBE TAME ETBE Ethanol Methanol t-Butanol DIPE Total OxygenContent

D 5845

Reproducibility(mass %) 0.98 1.36 0.77 0.59 0.37 0.59 0.79 0.30

samples tested in the r o u n d r o b i n a n d since a wide range o f base gasolines was n o t tested, it is not possible to offer a definitive s t a t e m e n t o f bias except to note that biases were observed in the r o u n d robin.

Ke~vords 15.1 alcohols; diisopropyl ether; ethanol; ethers; ethyl t e r t - b u t y l ether; methanol; methyl t e r t - b u t y l ether; motor gasoline; oxygenate; t e r l - a m y l methyl ether; t e r t - b u t a n o ] 15.

14.4 Bias--No consistent bias was observed with the

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reepproved or withdrawn. Your comments are Invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend, ff you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 100 Barr Harbor Drive, West Conshohockan, PA 19428.

992

(~1~l~ Designation: D 5853 - 95 Standard Test Method for Pour Point of Crude Oils 1 This standard is issued under the fixed designation D 5853; the number immedmtely following the designation indicates the year of original adoption or, in the case of revision, the year of last revismn. A number in parentheses indicates the year of last reapproval. A superscript epsilon (0 indicates an editorial change since the last revision or reapproval.

prescribed treatment designed to enhance gelation of wax crystals and solidification of the test specimen. 3.1.3 minimum (lower) pour point, n--the pour point obtained after the test specimen has been subjected to a prescribed treatment designed to delay gelation of wax crystals and solidification of the test specimen.

1. Scope 1.1 This test method covers two procedures for the determination of the pour point temperatures of crude oils down to -36"C. One method provides a measure of the maximum (upper) pour point temperature (Procedure A) and is described in 9.1; the other method provides a measure of the minimum (lower) pour point temperature (Procedure B) and is described in 9.2. 1.2 The use of this test method is limited to use for crude oils. Pour point temperatures of other petroleum products can be determined by Test Method D 97. 1.3 This standard does not purport to address all of the

4. Summary of Test Method 4.1 After preliminary heating, the test specimen is cooled at a specified rate and examined at intervals of 3"C for flow characteristics. The lowest temperature at which movement of the test specimen is observed is recorded as the pour point.

safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific

5. Significance and Use 5.1 The pour point of a crude oil is an index of the lowest temperature of handleability for certain applications. 5.2 This is the only pour point method specifically designed for crude oils. 5.3 The maximum and minimum pour point temperatures provide a temperature window where a crude oil, depending on its thermal history, might appear in the liquid as well as the solid state. 5.4 The test method can be used to supplement other measurements of cold flow behavior. It is especially useful for the screening of the effect of wax interaction modifiers on the flow behavior of crude oils.

hazard statements, see Section 7.

2. Referenced Documents

2.1 ASTM Standards: D 97 Test Method for Pour Point of Petroleum Products 2 D 130 Test Method for Detection of Copper Corrosion from Petroleum Products by the Copper Strip Tarnish Test2 D323 Test Method for Vapor Pressure of Petroleum Products (Reid Method) 2 D4057 Practice for Manual Sampling of Petroleum and Petroleum Products 3 D 4177 Practice for Automatic Sampling of Petroleum and Petroleum Products 3 E l Specification for ASTM Thermometers4 E 77 Test Method for Inspection and Verification of Thermometers4

6. Apparatus 6.1 Pour Point Test Apparatus Assembly (see Fig. 1): 6.1.1 Test Jar, cylindrical, of clear glass, fiat bottomed, outside diameter 33.2 to 34.8 mm, and height 115 to 125 ram. The inside diameter of the jar can range from 30.0 to 32.4 mm, within the constraint that the wall thickness shall be no greater than 1.6 mm. The jar shall have a line to indicate a sample height 54 + 3 mm above the inside bottom. The inside of the test jar (up to the mark) shall be visibly clean and free of scratches. 6.1.2 Thermometers, having ranges shown in the following table and conforming to the requirements prescribed in Specification E 1 for thermometers:

3. Terminology 3.1 Descriptions of Terms Specific to This Standard: 3.1.1 pour point, n - - t h e lowest temperature at which movement of the test specimen is observed under the conditions of the test. 3.1.2 maximum (upper) pour point, n D t h e pour point obtained after the test specimen has been subjected to a

Thermometer

' This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.07 on Flow Properties. Current edition approved Oct. 10, 1995. Published December 1995. 2 Annual Book of ASTM Standards, Vol 05.01. 3 Annual Book of ASTM Standards, Vol 05.02. 4 Annual Book of ASTM Standards, Vol 14.03. s This pressure vessel is identical to the pressure vessel described in Test Method D 130.

Thermometer

Temperature Range

High cloud and pour Low cloud and pour Melting point

- 3 8 to +50"C -80 to +20"C +32 to + 127°C

Number ASTM IP 5C 6C 6 IC

IC 2C 63C

6.1.2.1 Since separation of liquid column thermometers occasionally occurs and may escape detection, the ice point of the thermometers shall be checked prior to the test and used only if they are accurate within + I*C (see Test Method E 77). 993

~

D 5853

THERMOME 1 ER

44,2

-

45.8

IO.

30 - 32.4 IO 322 - 3 4 8 (313

COR~:

JACKET 25 MAX. • ~

COOLANTLEVEL

TEST JAR FILL LEVEL" GASKET

COOt_I~

BATH

l,_.,.I t

-

I I_.~__

t

OISK NOTE--All dimensions are stated in millimetres. FIG. 1

Apparatus for Pour Point Test

6.1.3 Cork, to fit the test jar, center bored for the test thermometer. 6.1.4 Jacket, watertight, cylindrical, metal, fiat bottomed, 115 + 3 m m depth, with inside diameter of 44.2 to 45.8 mm. It shall be supported in a vertical position in the cooling bath (6.1.7) so that no more than 25 mm projects out of the cooling medium. The jacket shall be capable of being cleaned. 6.1.5 Disk, cork or felt, 6 mm thick to fit loosely inside the jacket. 6.1.6 Gasket, to fit snugly around the outside of the test jar and loosely inside the jacket. The gasket shall be made of rubber, leather, or other material that is sufficiently elastic to cling to the test jar and hard enough to hold its shape. Its purpose is to prevent the test jar from touching the jacket. 6.1.7 Cooling Bath or Baths, of a type suitable for obtaining the required temperatures. The size and shape of the bath are options, but a support to hold the jacket firmly in a vertical position is essential. The bath temperature shall be monitored by means of the appropriate thermometer (6.1.2) or any other temperature measuring device capable of measuring and displaying the designated temperature with the required precision and accuracy. The required bath temperatures shall either be maintained by refrigeration or by suitable freezing mixtures (Note 1) and shall maintain the designated temperatures to within +_.1.5"C.

For Temperatures Down To 9"C -12"C -27"C -57"C

Ice and water Crushed ice and sodium chloride crystals Crushed ice and calcium chloride crystals Acetone or petroleum naphtha (see Section 7) chilled in a covered metal beaker with an ice-salt mixture to -12"C and then with enough solid carbon dioxide to give the desired temperature. 6.2 Water Bath--The size and shape of the bath are optional, but a support to hold the test jar immersed in the bath to above the sample height in the test jar and in a firm vertical position is required. The required bath temperature may be maintained by any suitable means, provided the temperature can be monitored and controlled to the designated temperature (+ I*C (9.1.4; 9.2.4)). 6.3 Pressure Vessel,~ constructed of stainless steel according to the dimensions given in Fig. 2, and capable of withstanding a test pressure of 700 kPa. Alternative designs for the pressure vessel cap and synthetic rubber gasket may be used provided that the internal dimensions of the pressure vessel are the same as those shown in Fig. 2. 6.4 Timing Device, capable of measuring up to 30 s with a resolution of at least 0.1 s and an accuracy of +0.2 s or better. 6 The results of the cooperative test program from which these values have been derived are filed at ASTM Headquarters. Request RR:D02-1371.

NOTE l--The cooling mixtures commonly used are as follows:

994

~

D 5853

Dimensions in miilimetres

ling eye C'q 2 wide groove for pressure relief ignu rleo cap - 12 threads per in NF thread or equivalent

,Synthetic rubber " 0 " ring free from free sulphur

Chamfer inside cap to protect " 0 " ring when clos/ng bomb

tube o q3

Material: sta,nless steel Welded construction Maximum test pressure, gauge 700 kPa [7 bar)

FIG. 2

Pressure Vessel

7. Reagents and Materials

NOTE 4: Warning--Flammable. Vapor harmful.

7.1 The following solvents of technical grade are appropriate for low-temperature bath media.

7.1.4 Petroleum Naphtha. NOTE 5: Warning--Combustible. Vapor harmful. NOTE 6--Typical petroleum naptha used for cleaning purposes are VM and P napthas.

7.1.1 Acetone. NOTE 2: Warning--Extremely flammable. 7.1.2 Alcohol, Ethanol

7.2 Toluene, technical grade.

NOTE 3: WarningwFlammable.

NOTE 7: Warning--Flammable. Vapor harmful.

7.1.3 Alcohol, Methanol.

7.3 Solid Carbon Dioxide. 995

~

D 5853

NOTE 8: WarningmExtremely cold (-78.5"C). 8. Sampling, Test Samples, and Test Specimens

NoTE 9--Sampling is defined as all steps required to obtain a portion of the contents of any pipe, tank, or other system and to place the sample into the laboratory test container.

8.1 Laboratory Sample--It is essential that the sample received by the laboratory is representative of the batch or lot of crude oil from which it was taken. Practices D 4057 and D 4177 provide guidance for obtaining such representative samples. 8.2 Preparation of Test SamplesmThe pour point of crude oils is very sensitive to trace amounts of high melting waxes. Exercise meticulous care to ensure such waxes, if present, are either completely melted or, if volatility constraints prevent heating to complete melting, homogeneously suspended in the sample (Appendix X l). Inspect the walls of the original container to ensure that no high melting point material is left sticking to the wall. NOTE 10--1t is not possible to define universal mandatory rules for the preparation of crude oil test samples. Guidelines for sample handling for the most common situations are given in Appendix X I. 9. Procedure

9.1 Procedure A for Maximum (Upper) Pour Point." 9.1.1 Pour the test sample into the test jar to the level mark. If necessary, reheat the test sample to a temperature at least 20"C above the expected pour point (8.2 and Appendix X 1) but not higher than a temperature of 60"C (see Note 11). NOTE 11: WarningmThe vapor pressure of crude oils at temperatures higher than 60"C will usually exceed 100 kPa. Under these circumstances the sample container may rupture. Opening of the container may induce foaming with resultant loss of sample and possible injury to personnel. 9.1.2 Immediately close the test jar with the cork carrying the high cloud and pour thermometer, or, if the expected pour point is above 36"C, the melting point thermometer. Adjust the position of the cork and thermometer so the cork fits tightly, the thermometer and the jar are coaxial, and the thermometer bulb is immersed to a depth that places the beginning of the capillary 3 m m below the surface of the test specimen. 9.1.3 Keep the test jar with the test specimen at room temperature (between 18 and 24"C) for at least 24 h. NOTE 12--The pour point of a crude oil is dependent on the state of crystallization of the wax in the test specimen. In crude oils, achieving equilibrium between crystallized wax and dissolved wax is a rather slow process. However, experience has shown that in a majority ofcases, such an equilibrium is reached within 24 h. 9.1.4 If the expected pour point is greater than 36"C, heat the sample to 9"C above the expected pour point. If the expected pour point is less than 36"C, heat the sample to a temperature of 45 _+ I*C. Maintain the water bath (6.2) to heat the sample at 48 + I*C or at a temperature 12"C higher than the expected pour point, whichever is higher. 9.1.4.1 As soon as the test specimen has reached the required temperature, remove the cork carrying the thermometer and stir the test specimen gently with a spatula or similar device. Put the cork carrying the thermometer back in place (see 9.1.2). 9.1.5 Ensure that the disk, gasket, and the inside of the

jacket are clean and dry. Place the disk in the bottom of the jacket. Place the disk and jacket in the cooling medium a m i n i m u m of 10 min before the test jar is inserted. The use of a jacket cover, while the empty jacket is cooling, is permitted. Remove the test jar from the water bath and dry with a tissue. Place the gasket around the test jar, 25 m m from the bottom. Insert the test jar into the jacket in the first bath maintained at 21"C and commence observations for pour point. Never place a test jar directly into the cooling medium. 9.1.6 Exercise care not to disturb the mass of test specimen nor permit the thermometer to shift in the test specimen; any disturbance of the spongy network of wax crystals will lead to a lower pour point and erroneous results (Note 12). NOTE 13--With dark colored materials, such as crude oils, it is impractical to observe, in the test jar, the onset of crystallization and network formation in the test specimen. Hence, it is presumed that network formation will begin at the very early stages of the cooling sequence. 9.1.7 Pour points are expressed in temperatures which are positive or negative multiples of 3"C. Begin to examine the appearance of the test specimen when the temperature of the test specimen is 9"C above the expected pour point (estimated as a multiple of 3"C). At each test thermometer reading which is a multiple of 3"C below the starting temperature, remove the test jar from the jacket. When necessary, remove moisture that limits visibility of the test specimen by wiping the surface of the test jar with a clean cloth moistened in alcohol at approximately the temperature of the test specimen in the jar. Then tilt the jar just enough to ascertain whether there is movement of the test specimen in the jar. When movement is observed, immediately return the test jar into the jacket. The complete operation of removal and replacement shall require not more than 3 s. 9.1.7.1 If the test specimen has not ceased to flow when its temperature has reached 30"C, transfer the test jar to the next lower temperature bath per the following schedule: (a) If the test specimen is at +30"C, move to 0*C bath; (b) If the test specimen is at +9"C, move to - 1 8 " C bath; (c) If the test specimen is at -9"C, move to -33"C bath; and (d) If the test specimen is at -24"C, move to - 5 1 " C bath. 9.1.7.2 As soon as the test specimen in the jar does not flow when tilted, hold the jar in a horizontal position for 5 s, as shown by an accurate timing device (6.4) and observe carefully. If the test specimen shows any movement, replace the test jar immediately in the jacket and repeat a test for flow at the next temperature, 3"C lower. 9.1.8 Continue in this manner until a point is reached at which the test specimen shows no movement when the test jar is held in a horizontal position for 5 s. Record the observed reading of the test temperature. 9.1.8.1 If the test specimen has reached -36"C and still shows movement, discontinue the test. NOTE 14--To determine compliance with existing specifications having pour point limits at temperatures not divisible by 3"C, it is acceptable practice to conduct the pour point measurement according to the following schedule. Begin to examine the appearance of the test specimen when the temperature of the test specimen is 9"C above the specification pour point. Continue observations at YC intervals as described in 9.1.6 and 9.1.7 until the specification temperature is 996

~) D 5853 report as Maximum Pour Point, ASTM D 5853, Procedure A, or Minimum Pour Point, ASTM D 5853, Procedure B, if the procedure in 9.2 has been followed. 10.2 If the test was discontinued (9.1.8.1), report the pour point as -<-36"C.

reached. Report the sample as passing or failing the specification limit.

9.2 Procedure B for Minimum (Lower) Pour Point: 9.2.1 Pour 50 g of the test sample into a clean pressure vessel (6.3 and Note 15). When necessary, reheat the test sample to a temperature of at least 20"C above the expected pour point (8.2 and Appendix X1) but not higher than 60"C (Note I 1). Check that the rubber ring is in place and screw the lid on tightly.

11. Precision and Bias 11.1 The following criteria are to be used for judging the acceptability of results (95 % confidence): 11.1.1 RepeatabilitynThe difference between successive test results obtained by the same operator with the same apparatus under constant operating conditions on identical test material would, in the long run, in the normal and correct operation of the test method, exceed the following value only in 1 case in 20.

NOTE 15raThe pressure vessel may be cleaned by any appropriate solvent, provided the solvent is capable of dissolving remnants of high melting wax and asphaltenes. Hot toluene (100*C) has been found to be an appropriate solvent for this purpose.

9.2.2 Heat the pressure vessel in an oil bath or by any other suitable means to a temperature of 105 + 2"C and leave at that temperature for at least 30 min. 9.2.3 Take the pressure vessel from the oil bath, wipe and dry the surface of the pressure vessel, swirl gently to homogenize the contents, and leave the pressure vessel to cool at room temperature for exactly 20 min. 9.2.4 Carefully open the pressure vessel (Note 16) and transfer the sample into the test jar filling to the level mark of the test jar, preheated in a water bath (6.2) kept at a temperature of 48 + l*C.

Procedure

A (max) B (rain)

Repeatability "C (rounded) 3.1 5.8

(3) (6)

(Note 17) (Note 17)

11.1.2 ReproducibilitymThe difference between two, single and independent results, obtained by different operators working in different laboratories on identical test material would, in the long run, in the normal and correct operation of the test method, exceed the following value only in 1 case in 20.

NOTE 16: Warning--After 20 min at ambient temperature, the temperature of the test specimen will be approximately 50"C. The vapor pressure at that temperature may still exceed 100 kPa. Under these circumstances, inattentive opening of the pressure vessel may induce foaming with resultant loss of sample and possible injury to personnel.

Procedure A (max) B (rain)

9.2.5 Immediately close the test jar with the cork carrying the high cloud and pour thermometer, or, if the expected pour point is above 36"C, the melting point thermometer. Adjust the position of the cork and thermometer so the cork fits tightly, the thermometer and the jar are coaxial, and the thermometer bulb is immersed to a depth which places the beginning of the capillary 3 mm below the surface of the test specimen. 9.2.6 Proceed as described in 9.1.5 through 9.1.8.

Reproducibility "C (rounded) 18.0 (18) 22.0 (21)

(Note 17) (Note 17)

NOtE 17--These precision values are derived from a 1994 cooperative program 6 and the current Committee D-2 Statistical Method, RR:D02-1007. A summary of the cooperative program and the relevant statistics is given in Appendix X2.

11.2 Bias--The procedure in this test method has no bias because the value of pour point is defined only in terms of this test method. 12. Keywords 12.1 cold flow; crude oil; pour point

10. Calculation and Report 10.1 Add 3"C to the temperature recorded in 9.1.8 and

APPENDIXES

(Nonmandatory Information) XI. GUIDELINE FOR SAMPLE HANDLING XI.I Introduction

the purpose for which it was taken. The laboratory analytical procedure to be used will often require a special handling procedure to be associated with it. For this reason, consult the appropriate methods of test so that any necessary instructions as to sample handling can be given to the person drawing the sample. If the analytical procedures to be applied have conflicting requirements, as is often the case for crude oils, then draw separate samples and apply the appropriate procedure to each sample. X1.1.4 For crude oils, care in sampling is particularly necessary because: X l.I.4.1 They contain volatile material, hence loss by evaporation can occur.

X l.l.1 Sampling of crude oils from pipelines, tankers, barges, or trucks is usually beyond control of the laboratory and adequately covered by the appropriate sampling protocols as specified in Practices D 4057 and D 4177. X l.l.2 This guideline covers the sampling from conminers submitted to the analytical laboratory for analysis. It covers the handling of samples between the point at which they were extracted or drawn, and the laboratory test bench or sample storage. It is meant to ensure that the nature and integrity of the samples are maintained as far as possible. X l.l.3 The method of handling a sample will depend on

997

@ o sssa extensive rolling for at least 30 min to disperse the wax and wax particles as effectively as possible. In order to avoid the cumbersome procedure of (re)mixing the contents of large sample containers, it is recommended to draw an adequate number of subsamples in smaller containers, using Practice D 4057 as a guide (XI.I.3 through Xl.I.7). NOTE X I.I: Warning--Before embarking on any heating or mixing procedure, or both, ensure that the drum and plugs can withstand the expected pressure build-up and can be handled safely without leakage. NOTE X 1.2: Warning--Exercise care when opening the container as significant vapor pressure will have built up (XI.2.3). Opening the container may induce foaming with resultant spillage of sample and possible injury to personnel.

X1.1.4.2 They contain water or sediment, or both, which tends to separate in the sample container. X 1.1.4.3 If not maintained at a sufficiently high temperature, wax deposition at the walls of the container or wax precipitation can occur. X1.1.5 When making up composite samples, exercise care not to lose light ends and to ensure homogeneity of the composing samples. X I.1.6 If crude oil samples are to be tested for vapor pressure, density, or any other test in which retention of light ends is essential, subsamples for these test methods shall be taken first before any other sample handling procedures are invoked for performing sampling for other tests such as pour point. X l.l.7 Never subsample crude oils in plastic containers or any other container that will not retain gases or light materials and cannot be heated without deformation. XI.2 Heating of Samples: X I.2.1 Crude oils stored at temperatures below their cloud point will show wax deposition on the walls of the (sample) containers. The wax coming out of the solution will be preferentially the high melting wax. It is this type of wax that has the most pronounced influence on the crude oil pour point and, at the same time, is the most difficult to redissolve or disperse in the crude oil. Proper treatment of the samples before subsampling for pour point, therefore, is crucial for obtaining reliable crude oil pour point results. X 1.2.2 In order to achieve complete solubility of the wax, heat crude oil samples to a temperature above the wax cloud point. This value is seldom known however. As a rule of thumb, a temperature of 20"C above the expected pour point will usually satisfy the cloud point requirement, although exceptions do occur. XI.2.3 The vast majority of crude oils show a significant vapor pressure even at ambient temperatures. Dead crude is usually stabilized at a vapor pressure of 50 kPa (Test Method D 323, RVP at 37.8"C) or below. However, occasionally, high RVP crudes (80 kPa) are produced and marketed. Before testing, never subject a crude oil sample to a temperature higher than 60"C or to a temperature above the bubble point (vapor pressure > 100 kPa). As a rule of thumb, the vapor pressure doubles for every 20"C increase in temperature. X 1.3 flomogenization of Samples." XI.3.1 The proper means and effectiveness of mixing in order to achieve homogeneity depend, in addition to the physical properties (for example, viscosity) of the crude oil, on the capacity and shape of the container in which the crude oil arrives at the laboratory. It is virtually impossible to cater to every possibility and achieve optimum results under all circumstances. Guidelines are provided which in actual practice have proven to achieve the best possible results for the most common situations. X1.3.2 Drums, 15 to 200 L: X 1.3.2.1 The most effective way of achieving homogenization is mixing the contents of the drum on a roller bank in a hot room kept at a temperature between 40 and 60"C for 48 h (XI.2.3). Alternatively, keep the drum at a temperature of 20"C above the expected pour point for 48 h (XI.2.3) and roll the drum for at least 15 min before taking a sample. If heating of the drum is not feasible, the only alternative is

XI.3.3 Tins, I to 15 L: X1.3.3.1 Store the container at a temperature 20"C above the expected pour point (Xl.2.1) preferably in a water bath kept at the appropriate temperature. Alternatively, store the container in an explosion-proof oven, bearing in mind that local surface temperatures might be much higher than the oven temperature reading indicates. The time required to dissolve the wax will depend on the type of wax and the size of the container. For a 1 L tin, 2 h has been found to be adequate. For larger tins, longer times will be required. Although it is strongly recommended that the containers be closed when heated, it is advised that after approximately 30 min, the excess pressure is slowly released before continuing the heating. (WARNING: Note X 1.2) Mixing can be accomplished by a mechanical shaker or by vigorous manual shaking. Although the use of (high speed) mixers or similar devices might be effective, it will require that the container be open for some time, during which the escape of light ends can be excessive, and hence, this procedure is not recommended. NOTE X I.3: Warning--During this operation significantamounts of highly flammable vapors might escape. Vent in a safe area. XI.3.4 Bottles: XI.3.4.1 Follow as described in XI.3.3. Exercise special care when heating bottles that are closed with a cork or rubber stopper. The pressure build-up due to the heating will inevitably blow out the stopper. Take proper measures to safeguard against such an event (Notes X1.1 and X1.2). X 1.3.5 Plastic Containers: XI.3.5.1 The use of plastic containers for crude oil samples is strongly discouraged for a number of reasons (XI.I.7). If such a container is offered to the laboratory, however, the only way to handle these containers is by heating to a temperature 20"C above the expected pour point (X 1.2.1 and X 1.2.3) in a water bath kept at the appropriate temperature. The water bath prevents localized high temperatures in the container, which can create weak sections increasing the possibility of rupture. In any case, rupture of these containers due to pressure build-up is a distinct possibility and adequate measures must be taken to ensure safety (Note XI.2). X 1.3.6 Sample Receivers (Practice D 4177): XI.3.6.1 Follow the prescribed sample mixing and handling procedure as described in Practice D4177. It is recommended that a 1 L (tin) subsample be taken concurrently with subsampling for density and water and sediment, provided that the sample receiver has not been below the crude oil cloud point for more than 6 h. If the container has 998

~) D 5853 been kept at a temperature below the cloud point for more then 6 h, reheat the container to a temperature 20"C above

the expected pour point (XI.2.1 and XI.2.3) before mixing and subsampling.

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and ff not revised, either reepproved or withdrawn. Your comments a r e invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend, ff you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 100 Barr Harbor Drive, West Conshohockan, PA 19428.

999

(~1~ Designation: D 5863 - 95 Standard Test Methods for Determination of Nickel, Vanadium, Iron, and Sodium in Crude Oils and Residual Fuels by Flame Atomic Absorption Spectrometry 1 This standard is issued under the fixed designation D 5863; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (0 indicates an editorial change since the last revision or reapproval.

1. Scope 1.1 These test methods cover the determination of nickel, vanadium, iron, and sodium in crude oils and residual fuels by flame atomic absorption spectrometry (AAS). Two different test methods are presented. 1.2 Test MethodA, Sections 7-12--Flame AAS is used to analyze a sample that is decomposed with acid for the determination of total Ni, V, and Fe. 1.3 Test Method B, Sections 13-17--Flame AAS is used to analyze a sample diluted with an organic solvent for the determination of Ni, V, and Na. This test method uses oil-soluble metals for calibration to determine dissolved metals and does not purport to quantitatively determine nor detect insoluble particulates. 1.4 The concentration ranges covered by these test methods are determined by the sensitivity of the instruments, the amount of sample taken for analysis, and the dilution volume. A specific statement is given in Note 3. 1.5 For each element, each test method has its own unique precision. The user can select the appropriate test method based on the precision required for the specific analysis. 1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Specific warning statements are given in Notes 1, 2, 5 and 6. 1.7 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.

E 288 Specification for Laboratory Glass Volumetric Flasks 5 E 969 Specification for Volumetric (Transfer) Pipets 5

3. Summary of Test Methods 3.1 Test Method A - - O n e to twenty grams of sample are weighed into a beaker and decomposed with concentrated sulfuric acid by heating to dryness. The residual carbon is burned off by heating at 525"C in a muffle furnace. The inorganic residue is digested in dilute nitric acid, evaporated to incipient dryness, dissolved in dilute nitric and made up to volume with dilute nitric acid. Interference suppressant is added to the dilute nitric acid solution. The solution is nebulized into the flame of an atomic absorption spectrometer. A nitrous oxide/acetylene flame is used for vanadium and an air/acetylene flame is used for nickel and iron. The instrument is calibrated with matrix-matched standard solutions. The measured absorption intensities are related to concentrations by the appropriate use of calibration data. 3.2 Test Method B--Sample is diluted with an organic solvent to give a test solution containing either 5 % (m/m) or 20 % (m/m) sample. The recommended sample concentration is dependent on the concentrations of the analytes in the sample. For the determination of vanadium, interference suppressant is added to the test solution. The test solution is nebulized into the flame of an atomic absorption spectrometer. A nitrous oxide/acetylene flame is used for vanadium and an air/acetylene flame is used for nickel and sodium. The measured absorption intensities are related to concentrations by the appropriate use of calibration data. 4. Significance and Use 4.1 When fuels are combusted, metals present in the fuels can form low melting compounds that are corrosive to metal parts. Metals present at trace levels in petroleum can deactivate catalysts during processing. These test methods provide a means of quantitatively determining the concentrations of vanadium, nickel, iron, and sodium. Thus, these test methods can be used to aid in determining the quality and value of the crude oil and residual oil.

2. Referenced Documents 2.1 A S T M Standards: D 1193 Specification for Reagent Water 2 D 1548 Test Method for Vanadium in Heavy Fuel Oil 3 D4057 Practice for Manual Sampling of Petroleum and Petroleum Products 4 D 4177 Practice for Automatic Sampling of Petroleum and Petroleum Products 4 J These test methods are under the jurisdiction of ASTM Committee I)-2 on Petroleum Products and Lubricants and are the direct responsibility of Subcommittee D02.03.0B on Elemental Analysis. Current edition approved Dec. 10, 1995. Published February 1996. 2 Annual Book of ASTM Standards, Vol 11.01. 3 Annual Book of ASTM Standards, Vol 05.01. 4 Annual Book of ASTM Standards, Vol 05.02.

5. Purity of Reagents 5.1 Reagent grade chemicals shall be used for all tests. Unless otherwise indicated, it is intended that all reagents conform to the specifications of the Committee on Analyt-

1000

5 Annual Book of ASTM Standards, Vol 14.02.

o sss3 ical Reagents of the American Chemical Society where such specifications are available. 6 Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination. 5.2 When determining metals at concentrations less than 1 mg/kg, use ultra-pure grade reagents. 5.3 Purity of Water--Unless otherwise indicated, reference to water shall be understood to mean reagent water conforming to Type II of Specification D 1193.

- - - I n f r a r e d Lamp

Vycor Vessel

6. Sampling and Sample Handling 6.1 The objective of sampling is to obtain a sample for testing purposes that is representative of the entire quantity. Only representative samples obtained as specified in Practices D 4057 and D 4177 shall be used. Do not fill the sample container more than two-thirds full 6.2 Prior to weighing, stir the sample and then shake the sample in its container. If the sample does not readily flow at room temperature, heat the sample to a sufficiently high and safe temperature to ensure adequate fluidity.

i

.~, ~

Air Bath

..._.. ~

Sample

~

Hot Plate

i

FIG. 1

TEST METHOD A--FLAME ATOMIC ABSORPTION AFTER ACID DECOMPOSITION OF THE SAMPLE

Decomposition Apparatus

7. Apparatus 7.1 Atomic Absorption Spectrometer, complete instrument with hollow cathode lamps and burners with gas supplies to support air-acetylene and nitrous oxide-acetylene flames (Warningmsee Note 1). NOTE 1: Warning--Hazardous. Potentially toxic and explosive. Refer to the manufacturer's instrument manual for associated safety hazards.

7.2 Sample Decomposition Apparatus (optional)--This apparatus is described in Fig. 1. It consists of a Vycor or Pyrex 400-mL beaker for the test solution, an air bath (Fig. 2) that rests on a hot plate and a 250 W infrared lamp supported 2.5 cm above the air bath. A variable transformer controls the voltage applied to the lamp. 7.3 Glassware--Vycor or Pyrex 400-mL beakers, volumetric flasks of various capacities and pipettes of various capacities. When determining concentrations below 1 rag/ kg, all glassware must be thoroughly cleaned (or soaked overnight) with 5 % HNO3 and rinsed five times with water. 7.4 Electric Muffle Furnace, capable of maintaining 525 + 25"C and sufficiently large to accommodate 400-mL beakers. The capability of an oxygen bleed is advantageous and optional. 7.5 Steam Bath. 7.6 Temperature Controlled Hot Plate, (optional). 7.7 Drying Oven, (optional), explosion-proof, if used to heat crude oils to obtain fluidity.

8. Reagents 8.1 Aqueous Standard Solutionsmlndividual

1

II

6 " E"

;

a ±"--,,-t

7 "

3T

j_

.%

5"

~1

1__%1 2 --

NOTE--All parts 16 gage (1.5 ram, 0,060 in.) aluminum. All dimensions are in

inches.

aqueous

Metric Equivalents

6 Reagent Chemicals, American Chemwal Soctety Specifications, American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed by the American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockvtlle, MD.

1001

in.

mm

in.

mm

1 11/= 2 31/la

25.4 38.1 50.8 77.8

37/a 5 61/2

98.4 127 165.1

FIG. 2

Air Bath

(@) D 5 8 6 3 standards with 1000 mg/kg concentrations of vanadium, nickel, and iron, purchased or prepared in acid matrix to ensure stability. 8.2 Nitric Acid--Concentrated nitric acid, HNO 3 (Warning--see Note 2). NOTE 2: Warning--Poison, oxidizer. Causes severe burns. Harmful or fatal if swallowed or inhaled.

8.3 Nitric Acid 50 % (V/V)nCarefully add, with stirring, one volume of concentrated nitric acid to one volume of water. 8.4 Dilute Nitric Acid, 5 % (V/V)nCarefully add, with stirring, one volume of concentrated nitric acid to 19 volumes of water. 8.5 Sulfuric Acid--Concentrated sulfuric acid, H 2 S O 4 (Warning--see Note 2). 8.6 Aluminum Nitrate, AI(NO3) 3 9HOH. 8.7 Potassium Nitrate, KNO3.

9. Preparation of Standards 9.1 Multi-Element Standard--Using the aqueous standard solutions, prepare a multi-element standard containing 100 mg/kg each of vanadium, nickel, and iron. Standards should be prepared to ensure accuracy and stability and should be stored in clean containers to safeguard against physical degradation. 9.2 Working Standards--Prepare at least two working standards to cover the concentration ranges specified in Table 1. For vanadium, add the specified interference suppressant. Each working standard must contain 5 % (V/V) nitric acid. Standards should be prepared to ensure accuracy and stability and should be stored in clean containers to safeguard against physical degradation. 9.3 Standard Blank, the standard blank contains 5 % (V/V) nitric acid and any interference suppressant specified in Table 1. 9.4 Check Standard--Prepare a calibration check standard in the same way as the working standards and at analyte concentrations that are typical of the specimens being analyzed. 10. Preparation of Test Solutions 10.1 Into a beaker, weigh an amount of sample estimated to contain between 0.0025 and 0.12 mg of each metal to be determined. A typical mass is 10 g. Add 0.5 mL of H2SO 4 for each gram of sample. NOTE 3--1f it is desired to extend the lower concentration limits of

the test method, it is recommended that the decomposition be done in 10-gincrements up to a maximum of 100 g. It is not necessaryto destroy all the organic matter each time before adding additional amounts ofthe sample and acid. When it is desired to determine higher concentrations, reduce the sample size accordingly. TABLE 1 AAS Conditions for the Determination of Vanadium, Nickel, and Iron Following Acid Sample Decomposition Element Vanadium

Wavelength, Concentration Interference nm Range, ltg/mL Suppressant 318.4

0.5-20

250 gg/mL AI, AI(NO3)a in

Flame N20-C=H=

5 • (v/v)

Nickel Iron

232.0 248.3

0.5-20 3.0-10

HNO3 None None

10.2 At the same time prepare reagent blanks using the same amount of sulfuric acid as used for sample decomposition. Reagent blanks should be carried through the same procedure as the samples. NOTE 4: Caution--Reagent blanks are critical when determining concentrations below 1 mg/kg. To simplify the analysis, use the same volume of acid and the same dilutions as used for the samples. For example, if 20 g of sample is being decomposed, use l0 mL of sulfuric acid for the reagent blank.

10.3 The use of the air bath apparatus (Fig. 2) is optional. Place the beaker in the air bath, which is located in the hood. The hot plate is off at this time. Heat gently from the top with the infrared lamp (Fig. 1) while stirring the test solution with a glass rod. As decomposition proceeds (indicated by a frothing and foaming), control the heat of the infrared lamp to maintain steady evolution of fumes. Give constant attention to each sample mixture until all risk of spattering and foaming is past. Then, gradually increase the temperature of both the hot plate and lamp until the sample is reduced to a carbonaceous ash. 10.4 If the air bath apparatus is not used, heat the sample and acid on a temperature controlled hot plate. As described in 10.3, monitor the decomposition reaction and adjust the temperature of the hot plate accordingly. NOTE 5: Precaution--Hot fuming concentrated sulfuric acid is very corrosive and a strong oxidizing acid. The analyst should work in a well-ventilated hood and wear rubber gloves and a suitable face shield to protect against spattering acid.

10.5 Place the sample in the muffle furnace maintained at 525 + 25°C. Optionally, introduce a gentle stream of oxygen into the furnace to expedite oxidation. Continue to heat until the carbon is completely removed. 10.6 Dissolve the inorganic residue by washing down the wall of the beaker with about 10 mL of the 1+1 HNO 3. Digest on a steam bath for 15 to 30 rain. Transfer to a hot plate and gently evaporate to incipient dryness. 10.7 Wash down the wall of the beaker with about 10 mL of dilute nitric acid (5 % V/V). Digest on the steam bath until all salts are dissolved. Allow to cool. Transfer quantitatively to a volumetric flask of suitable volume and make up to volume with dilute nitric acid. This is the test solution. 10.8 Pipette aliquots of the test solution into two separate volumetric flasks. Retain one flask for the determination of nickel and iron. To the other flask add aluminum interference suppressant for vanadium determination (refer to Table 1) and dilute up to mark with dilute nitric acid (5 % V/V). Similarly, prepare a reagent blank solution for vanadium analysis.

11. Preparation of Apparatus 11.1 Consult the manufacturer's instructions for the operation of the atomic absorption spectrometer. This test method assumes that good operating procedures are followed. Design differences between spectrometers make it impractical to exactly specify required instrument settings. 11.2 Set up the instrument to determine each analyte sequentially. 12. Calibration and Analysis 12.1 For each analyte in turn, perform the following operation.

Air-C=H= Air-C=H=

1002

~

D 5863

A A S Conditions for the Determination of Vanadium, Nickel, and Sodium Following Solvent Dilution of the Sample

TABLE 2 Element

Wavelength, nm

Concentration Range, mg/kg

Interference Suppressant

Flame

Vanadium Nickel Sodium

318.4 232.0 589.0

0.5-15 0.5-20 0.1-5

15 mg/kg AIA None None

N20-C2H = Air-C2H 2 Air-C2H =

TABLE 3

'* Prepared from an organometallic standard, mineral ell, and dilution solvent.

12.2 Nebulize the appropriate blank standard and zero the instrument. 12.3 Nebulize the working standards, determine the absorbance and construct a calibration curve of absorbance versus analyte concentration utilizing the instrument's concentration mode if available, otherwise plot these values. 12.4 Use the check standard to determine if the calibration for each analyte is accurate. If the results obtained on the check standard are not within +5 % of the expected concentration for each analyte, take corrective action and repeat the calibration. 12.5 Nebulize the test solutions and measure and record the absorbance. If appropriate, blank correct this absorbance by subtracting the reagent blank absorbance. 12.6 After measuring absorbances for a test solution, check the blank standard. If this does not read zero, check the system and then repeat steps 12.2 through 12.5. 12.7 Test solutions that give absorbances greater than that obtained with the most concentrated working standard must be diluted. The dilution must contain interference suppressant at the specified concentrations. TEST M E T l i O D B - - F L A M E ATOMIC ABSORPTION WITH AN ORGANIC SOLVENT TEST SOLUTION

13. Apparatus 13.1 Refer to Section 7.1. 13.2 Test Solution ContainersmGlass or plastic vials or bottles, with screw caps and a capacity of between 50 to 100 mL. Glass bottles of 100-mL capacity are satisfactory. 14. Reagents 14.1 Dilution Solvent--Mixed xylenes, o-xylene, tetralin and mixed paraffin-aromatic solvents are satisfactory (Warning--see Note 6). Solvent purity can affect analytical accuracy when the sample contains low concentrations (typically, a few mg/kg) of the analytes. NOTE 6: Warning--Combustible. Vapor harmful.

14.2 Mineral Oil--A high-purity oil such as U.S.P. white oil. 14.3 Organometallic Standards--Pre-prepared multi-element concentrates containing 100 mg/kg concentrations of each element are satisfactory. 7

15. Preparation of Standards and Test Solutions 15.1 Test Solution--Weigh a portion of well-mixed sample into a container and add solvent to achieve a sample concentration of either 5 % (m/m) or 20 % (m/m). Mix well. If the concentration of V, Ni, or Na in the sample exceeds 20 v Standards from the following source have been found satisfactory for this purpose: Conoco, Inc., Conostan Division, P.O. Box 1269, Ponca City, OK 74602.

1003

Element

Concentration Range, mg/kg

Vanad=um

50-500

Nickel

10-100

Iron Sodium

3-10 1-20

Repeatability Test Method A B A B A B

Repeatability, mg/kgA 1. lX °.r'° 0.13X °.92 0.20X o ss 0.005X T M 0.98 0.67X o.sa

A X = mean concentration, mg/kg.

mg/kg, the analysis for that element is performed on a test solution containing 5 % (m/m) sample. For concentrations less than 20 mg/kg, the analysis for that element is performed on a test solution that contains 20 % (m/m) sample. 15.2 Standards--If the test solution contains 5 % (m/m) sample, then the corresponding working standards and check standard must contain 5 % (m/m) oil. Similarly, if the test solution contains 20 % (m/m) sample, the standards must contain 20 % (m/m) oil. A consistent dilution factor is necessary so that all aspirated samples and standards will have the same viscosity. This is essential to obtain consistent uptake rates. 15.2.1 Working Standards--Prepare a blank (from mineral oil) and three additional working standards (from the organometallic standards) that cover the ranges of concentration specified in Table 2. 15.2.2 Check StandardmUsing the organometaUic standards, mineral oil, and dilution solvent, prepare a check standard to contain analyte concentrations approximately the same as expected in the test solutions.

16. Preparation of Apparatus 16.1 Refer to Section 11. 17. Calibration and Analysis 17.1 Refer to Section 12. 18. Calculation 18.1 For Test Method A, calculate the concentration of each analyte in the sample using the following equation: analyte concentration, rng/kg = (C x V x F)/W ( 1) where: C = concentration of the analyte in the test solution (corrected for the concentration determined in the reagent blank), txg/mL, V = volume of the test solution, mL, F = dilution factor, volume/volume or mass/mass, and W = sample mass, g. 18.2 For Test Method B, calculate the concentration of each analyte in the sample using the following equation. analyte concentration, mg/kg = C x F (2) where: C = concentration of the analyte in the test solution, mg/kg, and F = dilution factor, volume/volume or mass/mass. 19. Report 19.1 Report the following information: 19.1.1 Report concentrations in mg/kg to two significant figures.

(~) D 5863 TABLE 4

Element Vanadium

Calculated Repeatability (mg/kg) at Selected Concentrations (mg/kg) Test Method

Concentration 1

10

A

B Nickel

A

B Iron Sodium

A B

TABLE 5

0.12

0.89 0.13 0.98 1.2

Element

Concentration Range, mg/kg

Reproducibility Test Method

50

100

500

Vanadium

50-500

7.8 4.8 2.5 1.2

11.0 9.0 4.0 3.2

25.0 40.0

Nickel

10-100

A B A

3-10 1-20

A B

0.33Xo.=° 1.2Xo.°° 1.3X°-~ 0.06X1.= 1.45Xo.¢s 0.67X1.o

B Iron Sodium

Reproducibility, mg/kg A

" X = mean concentration, mg/kg.

20. Precision and Bias a

TABLE 6

20.1 Precision--The precision of this test method was determined by statistical analysis on interlaboratory test results. For Test Methods A and B, six cooperators participated in the interlaboratory study. Seven samples (four residual oils and three crude oils) comprised the test set. One residual oil was NIST SRM 1618. 6 One crude oil was NIST SRM 8505. 9 20.1.1 Repeatability---The difference between two test results, obtained by the same operator with the same apparatus under constant operating conditions on identical test materials would, in the long run, in the normal and correct operation of the test method, exceed the values in Tables 3 and 4 only in one case in twenty. 20.1.2 Reproducibility--The difference between two single and independent results, obtained by different operators working in different laboratories on identical test matedais, would in the long run, in the normal and correct operation of the test method, exceed the values in Tables 5 and 6 only in one case in twenty. 20.2 Bias--Bias was evaluated from results obtained on a Request RR:D02-1351 for intedaboratory study data. Available from ASTM Headquarters. 9Available from the National Institute of Standards and Technology, Gaithersburg, MD 20899.

Calculated Reproducibility (mg/kg) at Selected

Concentrations (mg/kg) Element Vanadium Nickel Iron Sodium

Test Method A B A B A B

Concentration 1

0.59

10

4.4 0.95 4.1 6.9

50

100

500

11.0 27.0 10.0 6.6

21.0 48.0 15.0 15.0

89.0 170.0

two NIST samples. For Test Method A, the means of the reported values for V and Ni do not differ from the corresponding expected values by more than the repeatability of the test method. For Test Method B, the mean of the reported values for V does not differ from the corresponding expected value by more than the repeatability of the test method, and the mean of the reported values for Ni is higher than the expected value by an amount approximately equal to twice the repeatability of the test method. Standard reference materials for Fe and Na are not available, so bias was not determined for these elements.

21. Keywords 21.1 atomic absorption spectrometry; AAS; iron; nickel; sodium; vanadium

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted In connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, ere entirely their own responsibility. This standard is subject to revision at any time by the responsible technical comm~ee and must be reviewed every five years and if not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at e meeting of the responsible technical committee, which you may attend. If you feel that your comments have not received • fair hearing you should make your views known to the ASTM Committee on Standards, 100 Barr Harbor Drive, West Conshohocken, PA 19428.

1004

~l[ ~ Designation: D 5917 - 96 Standard Test Method for Trace Impurities in Monocyclic Aromatic Hydrocarbons by Gas Chromatography and External Calibration 1 This standard is issued under the fixed designation D 5917; the number immediately following the designation indicates the year of original adoption or, in the ease of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (~) indicates an editorial change since the last revision or reapproval.

1. Scope 1.1 This test method covers the determination of the total nonaromatic hydrocarbons and trace monocyclic aromatic hydrocarbons in toluene and mixed xylenes by gas chromatography. The purity of toluene or mixed xylenes can also be calculated. Calibration of the gas chromatographic system is done by the external standard calibration technique. A similar test method, using the internal standard calibration technique, is Test Method D 2360. 1.2 Total aliphatic hydrocarbons containing 1 through 10 carbon atoms (methane through decanes) can be detected by this test method at concentrations ranging from 0.001 to 2.500 weight %. 1.2.1 A small amount of benzene in mixed xylenes may not be distinguished from the nonaromatics and the concentrations are determined as a composite (see 6.1). 1.3 Monocyclic aromatic hydrocarbon impurities containing 6 through 9 carbon atoms (benzene through C9 aromatics) can be detected by this test method at individual concentrations ranging from 0.001 to 1.000 weight %. 1.4 The following applies to all specified limits in this test method: for purposes of determining conformance with this test method, an observed value or a calculated value shall be rounded off "to the nearest unit" in the last fight-hand digit used in expressing the specification limit, in accordance with the rounding-off method of Practice E 29. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statement, see Section 9.

2. Referenced Documents 2.1 A S T M Standards: D 841 Specification for Nitration Grade Toluene2 D 2306 Test Method for C8 Hydrocarbon Analysis by Gas Chromatography2 D 2360 Test Method for Trace Impurities in Monocyclic Aromatic Hydrocarbons by Gas Chromatography2 D 3437 Practice for Sampling and Handling Liquid Cyclic Products2

D 4052 Test Method for Density and Relative Density of Liquids by Digital Density Meter3 D 4307 Practice for Preparation of Liquid Blends for Use as Analytical Standards3 D4534 Test Method for Benzene Content of Cyclic Products by Gas Chromatography2 D 4790 Terminology of Aromatic Hydrocarbons and Related Chemicals: D 5211 Specification for Xylenes for p-Xylene Feedstock2 E 29 Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications 4 E 260 Practice for Packed Column Gas Chromatography4 E 355 Practice for Gas Chromatography Terms and Relationships4 E 691 Practice for Conducting an Interlaboratory Test Program to Determine the Precision of Test Methods4 E 1510 Practice for Installing Fused Silica Open Tubular Capillary Columns in Gas Chromatographs4 2.2 Other Document: OSHA Regulations, 29 CFR, paragraphs 1910.1000 and 1910.12005

3. Terminology 3.1 See Terminology D 4790 for definitions of terms used in this test method. 4. Summary of Test Method 4.1 A repeatable volume of the specimen to be analyzed is precisely injected into a gas chromatograph equipped with a flame ionization detector (FID). The peak area of each impurity is measured. Concentration of each impurity is determined from the linear calibration curve of peak area versus concentration. Purity by gas chromatography (GC) is calculated by subtracting the sum of the impurities found from 100.00. Results are reported in weight percent. 5. Significance and Use 5.1 Determining the type and amount of hydrocarbon impurities remaining from the manufacture of toluene and mixed xylenes used as chemical intermediates and solvents is often required. This test method is suitable for setting specifications and for use as an internal quality control tool where these products are produced or are used. Typical impurities are: alkanes containing 1 to 10 carbons atoms,

This test method is under the jurisdiction of ASTM Committee D-16 on Aromatic Hydrocarbons and Related Chemicals and is the direct responsibility of Subcommittee DI6.0E on Instrumental Analysis. Current edition approved Feb. 10, 1996. Published April 1996. 2 Annual Book of ASTM Standards, Vol 06.04.

1005

3 Annual Book of ASTM Standards, Vol 05.02. 4 Annual Book of ASTM Standards, Vol 14.02. 5 Available from Superintendent of Documents, U.S. Government Printing Office, Washington, DC 20402.

(@) D 5 9 1 7 benzene, toluene, ethylbenzene (EB), xylenes, and aromatic hydrocarbons containing nine carbon atoms. 5.1.1 Refer to Test Method D 2306 for determining the Cs aromatic hydrocarbon distribution in mixed xylenes. 5.2 Purity is commonly reported by subtracting the determined expected impurities from 100.00. However, a gas chromatographic analysis cannot determine absolute purity if unknown or undetected components are contained within the material being examined. 5.3 This test method is similar to Test Method D 2360, however, interlaboratory testing has indicated a bias may exist between the two methods. Therefore the user is cautioned that the two methods may not give comparable results. 6. Interferences 6.1 In some cases for mixed xylenes, it may be difficult to resolve benzene from the nonaromatic hydrocarbons. Therefore the concentrations are determined as a composite. In the event that the benzene concentration must be determined, an alternate method such as Test Method D 4534 must be selected to ensure an accurate assessment of the benzene concentration.

7. Apparatus

7.1 Gas Chromatograph--Any instrument having a flame ionization detector that can be operated at the conditions given in Table 1. The system should have sufficient sensitivity to obtain a minimum peak height response for 0.001 weight % impurity twice the height of the background noise. 7.2 Columns--A capillary column containing a stationary phase of cross linked polyethylene glycol has been found satisfactory. 7.3 Recorder--Electronic integration is recommended. 7.4 Injector--The specimen must be precisely and repeatably injected into the gas chromatograph. An automatic sample injection device is highly recommended although manual injection can be employed if the criteria in 12.7 can be satisfied. 7.5 Volumetric Flask, 100-mL capacity. 7.6 Syringe, 100 ~L. TABLE 1 Method Parameters Inlet Temperature, °C Column: Tubing Length, m Intemel diameter, mm Stationary phase Film thickness, p.m Column temperature program Initial temperature, °C Initial time, mm Programming rate, °C/min Final, =C Time 2, rain Carder gas Linear velocity, cm/s at 145°C Split ratio Sample size, ttL Detector: Temperature, °C Analysis time, min

Split 270 fused silica 60 0.32 crosslinked polyethylene glycol 0.25

8. Reagents

8.1 Purity of Reagent--Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society,6 where such specifications are available. 8.2 Carrier Gas--Chromatographic grade helium or hydrogen is recommended. 8.3 High Purity p-Xylene, 99.999 weight % or greater purity. 8.3.1 Most p-xylene is available commercially at a purity less than 99.9 % and can be purified by recrystallization. To prepare 1.9 L of high purity p-xylene, begin with approximately 3.8 L of material and cool in a flammable storage freezer at -10 + 5°C until approximately I/2 to 3/4 of the p-xylene has frozen. This should require about 5 h. Remove the sample and decant the liquid portion. The solid portion is the purified p-xylene. Allow the p-xylene to thaw and repeat the crystallization procedure on the remaining sample until the p-xylene is free of contamination as indicated by gas chromatography. 8.4 Pure compounds for calibration, shall include nnonane, benzene, toluene, ethylbenzene, o-xylene, and cumene. The purity of all reagents should be >99 weight %. If the purity is less than 99 %, the concentration and identification of impurities must be known so that the composition of the standard can be adjusted for the presence of the impurities. 9. Hazards 9.1 Consult current OSHA regulations, supplier's Material Safety Data Sheets, and local regulations for all materials used in this test method. 10. Sampling 10.1 Sample the material in accordance with Practice D 3437. 11. Preparation of Apparatus 11.1 Follow manufacturer's instructions for mounting and conditioning the column into the chromatograph and adjusting the instrument to the conditions described in Table 2, allowing sufficient time for the equipment to reach equilibrium. See Practices E260, E 355, and E 1510 for additional information on gas chromatography practices and terminology. 12. Calibration 12.1 Prepare a synthetic mixture of high purity p-xylene containing impurities at concentrations representative of those expected in the samples to be analyzed. The volume of each hydrocarbon impurity must be measured to the nearest 1 ~L and all liquid reference compounds must be brought to the same temperature before mixing. Refer to Table 3 for an

60 10 5 150 10 helium 20 100:1 1.0 flame ionization 300 30

6 Reagent Chemicals, American Chemical Society Specifications, American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed by the American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville, MD.

1006

o s91z TABLE 2

Preparation

Compound

Density'~

p-Xylene (see 8.3.1) Benzene Toluene Ethylbanzene o-Xylene Cumane n-Nonane

0.857 0.874 0.862 0.863 0.876 0.857 0.714

Cumene will represent the aromatic hydrocarbons containing nine carbon atoms or greater (C9 aromatics). 12.l.l Prior to preparing the calibration standard, all reference compounds and any samples to be analyzed must be brought to the same temperature, preferably 25"C. 12.2 Using the exact volumes and densities in Table 2, calculate the weight % concentration for each impurity in the calibration blend as follows: C I = 100 D i V i / t V ~ D p ) (1)

Blend

of Calibration

Recommended ResultingConcentration Vol, p.L Volume 7, Weight 99.72 20.0 20.0 100.0 100.0 20.0 20.0

99.72 0.020 0.020 0.100 0.100 0.020 0.020

99.72 0.020 0.020 0.101 0.099 0.020 0.017

A Density at 25"C. Values obtained from "Physical Constants of Hydrocarbons C1 to Clo'; ASTM Publication DS 4A, 1971.

TABLE 3

Intermediate

Toluene

Precision

and

Reproducibility

Intermediate Precision

Nonaromatics (0.017) Ethylbenzene(0.017) p-Xylene (0.009) m-Xylane (0.013) o-Xylane (0.001) Toluene (99.94)

Reproducibility

0.0040 0.0014 0.0025 0.0013 0.0003 0.016

Mixed Xylanes

0.0083 0.0030 0.0027 0.0025 0.0005 0.021

Intermediate Precision

Nonaromatics (2.288) Toluene (0.675) Cumane (0.010) Xylenes (98.93)

where: D t = density of impurity i from Table 2, V; = volume of impurity i, mL, Dp - density ofp-xylene from Table 2, Vt = total volume of standard blend, mL, and C; = concentration of impurity i, weight %. 12.2.1 Alternatively, calibration standards may be used that have been gravimetrically prepared in accordance with Practice D 4307. 12.3 Inject the resulting solution from 12.1 into the chromatograph, collect and process the data. A typical chromatogram is illustrated in Fig. 1. 12.4 Determine the response factor for each impurity in the calibration mixture as follows: RFi = Ci/Al (2)

Reproducibility

0.1039 0.0244 0.0006 0.128

0.3688 0.1580 0.0020 0.369

where: RF# = response factor for impurity i, Az. = peak area of impurity i, and

example of a calibration blend, n-Nonane will represent the nonaromatic fraction and o-xylene the xylene fraction.

o-Xylene

\

p-Xylene Benzene

\

Toluene Ethylbenzene NonArcmatlca

i

....... \I --

1

0.0

!

I

1

[

2.0

I

I

!

I

4.0

I

'

I

'

6.0

'

'

'

I

'

'

'

8.0

'

[ ' iO.O

'

'

I

i2.0

'

'

'

'

I

t4.0

~4INUTES FIG. 1

Typical Chromatogram

1007

of Calibration

Standard

'

'

'

'

I

i5.0

'

'

'

'

I

i9.0

'

'

'

'

I

~.0.0

~

D 5917

C; = concentration of impurity i, as calculated in 12.2, weight %. 12.5 Analyze the calibration solution(s) a minimum of three times and calculate an average RF. 12.6 Determine the sample standard deviation for R F of each impurity using a scientific calculator or spreadsheet program. Determine the coefficient of variation for each R F as follows: CV i = 100 SDi/Avg i

tent with those made on the calibration blend. The nonaromatic fraction includes all peaks up to toluene (except for the peak assigned as benzene). Sum together all the nonaromatic peaks and report as a total area. The C9 aromatics fraction includes cumene and all peaks emerging after o-xylene. Sum together all the C9 aromatic peaks and report as a total area. 13.4 Figure 2 illustrates the analysis of Specification D 841, Toluene. Figure 3 illustrates the analysis of Specification D 5211, Mixed Xylenes.

(3)

where: CV, = coefficient of variation for RFi, SDi = standard deviation for RFi, and Avg i = average RF of impurity i.

14. Calculations 14.1 Calculate the weight percent concentration of the total nonaromatics and each impurity as follows. Use the response factor determined for n-nonane for all nonaromatic components, the factor for o-xylene for all xylenes, and the factor for cumene for all aromatic hydrocarbons containing nine or more carbon atoms as follows: C, ffi A,RFiDe/Ds (4) where: C, = concentration of impurity i, weight %, A/ = peak area of impurity i, RF, --- response factor of impurity i, from 12.4, D c = density of calibration solution (p-xylene), from Table 2, and D s ----density of sample, from Table 2 or Test Method D 4052. 14.2 Calculate the weight percent purity of the sample as follows:

12.7 The coefficient of variation for the response factor of any impurity, as calculated from a minimum of three successive analyses of the standard, shall not exceed 10 %. 13. Procedure 13.1 Bring the sample and calibration mixtures to identical temperatures, preferably 25"C. Make sure that the temperature of the sample is consistent with that of the calibration standard prepared in Section 12. 13.2 Depending upon the actual chromatograph's operating conditions, inject an appropriate amount of sample into the instrument. The injection amount shall be identical to the amount used in 12.3 and must be consistent with those conditions used to meet the criteria in 12.7. 13.3 Measure the area of all peaks except the major component(s). Measurements on the sample must be consis-

Toluene

Ethylbenzene ~Xylene

l

NonAromatics

.... I

0.0

!

I-~

I

2.0

I

I

,

4.0

6.0

8.0

o-Xylene ,

~,,,

, ~--{--r~-~--T--T--I--T=~--l--

t0.0

12.0

I

,

' ' ~ I J ' T r-]--r--r-r-T

i4.0

MINUTES FIG. 2

TypicalChromat~ramofSpecificationD841, Toluene

1008

16.0

t8.0

] 20.0

(~ D 5917

p-~l~e m-~l~e

Ethylbenzene

o-X ' l e n e

/

Toluene

NonAromatics

C9 ~omatics --

I

0.0

I

I

I

I

2.0

'

'

'

I 4.0

'

'

r

l

'

6.0

"

i

,

,

,

t

,

8.0

I

,-1"-',

t0.0

I

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12.0

F

,

I

, M

t4.0

'

I

16.0

'

'

'

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l

18.0

'

'

' I 20.0

MINUTES FIG. 3

Typical C h r o m a t o g r a m of Specification D 5211, X y l e n e s

purity, weight % = 100.00 - Ct (5) where: C~ = total concentration of all impurities, weight %. 15. Report 15.1 Report individual impurities, total nonaromatics, and total C9 aromatics, to the nearest 0.001%. 15.2 For concentrations of impurities less than 0.001%, report as <0.001%, and consider as 0.000 in summation of impurities. 15.3 Report the total impurities to the nearest 0.01%. 15.4 Report purity as "purity (by GC)" to the nearest 0.01%. 16. Precision and Bias 7 16.1 Precision--The following criteria should be used to judge the acceptability of results obtained by this test method (95 % confidence level). The precision criteria was derived from an interlaboratory study using data submitted by six laboratories. Each round-robin participant was provided

with two calibration standards, a sample of mixed xylenes and a sample of toluene. Each sample was run twice in two days by two different operators. Results of the interlaboratory study were calculated and analyzed using Practice E 691. 16. I. l The numbers in parentheses shown in the left hand column of Table 3 are reported average concentrations of the impurities. 16.2 Intermediate Precision--Duplicate results by the same operator should not be considered suspect unless they differ by more than _+ the amount shown in Table 3. All values are in weight %. 16.3 Reproducibility--The results between two laboratories should not be considered suspect unless they differ by more than + the amount shown in Table 3. All values are in weight %. 16.4 Bias--Since there was no accepted reference material available at the time of interlaboratory testing, no statement on bias can be made at this time. 17. Keywords

7 Supporting data are available from ASTM Headquarters. Request RR: Dl6-1020.

1009

17.1 aromatics; external standard; gas chromatography; impurities; purity; toluene; xylenes

~'~ D 5917 The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted In connection with any item mentioned/n this standard. Users of this standard are expressly advised that datarm/nation of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsl~lity. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and ff not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful cons/daratlon at a meeting of the responsible technical committee, which you may attend, ff you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 100 Barr Harbor Drive, West Conshohonkan, PA 19428.

1010

(~

Designation:D 5986 - 96

Standard Test Method for Determination of Oxygenates, Benzene, Toluene, C8-C12 Aromatics and Total Aromatics in Finished Gasoline by Gas Chromatography/Fourier Transform Infrared Spectroscopy I This standard is issued under the fixed designation D 5986; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision, A number in parentheses indicates the year of last re,approval. A superscript epsilon (~) indicates an editorial change since the last revision or re,approval.

1. Scope 1.1 This test method covers the quantitative determination of oxygenates: methyl-t-butylether (MTBE), di-isopropyl ether (DIPE), ethyl-t-butylether (ETBE), t-amylmethyl ether (TAME), methanol (MeOH), ethanol (EtOH), 2-propanol (2-PrOH), t-butanol (t-BuOH), l-propanol (I-PrOH), 2-butanol (2-BuOH), i-butanol (i-BuOH), l-butanol (lBuOH); benzene, toluene and Cs-C~2 aromatics, and total aromatics in finished motor gasoline by gas chromatography/Fourier Transform infrared spectroscopy (GC/FTIR). 1.2 This test method covers the following concentration ranges: 0.1-20 volume % per component for ethers and alcohols; 0.1-2 volume % benzene; 1-15 volume % for toluene, 10-40 volume % total (C6-CI2) aromatics. 1.3 The method has not been tested by ASTM for refinery individual hydrocarbon process streams, such as reformates, fluid catalytic cracking naphthas, etc., used in blending of gasolines. 1.4 SI units of measurement are preferred and used throughout this test method. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 2. Referenced Documents

2.1 ASTM Standards: D 1298 Practice for Density, Relative Density (Specific Gravity), or API Gravity of Crude Petroleum and Liquid Petroleum Products by Hydrometer Method 2 D4052 Test Method for Density and Relative Density of Liquids by Digital Density Meter3 D4057 Practice for Manual Sampling of Petroleum and Petroleum Product 3 D4307 Practice for Preparation of Liquid Blends for Use as Analytical Standards3 3. Terminology 3.1 Definitions of Terms Specific to This Standard." 3.1.1 aromatics--refers to any organic compound conThis test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responslbihty of Subcommittee 1302.04 on Hydrocarbon Analysis. Current edition approved July 10, 1996. Published September 1996. 2 Annual Book of ASTM Standards, Vol 05.01. 3 Annual Book of ASTM Standards, Vol 05.02.

taining a benzene or naphthalene ring. 3.1.2 calibrated aromatic component--in this test method, refers to the individual aromatic components which have a specific calibration. 3.1.3 cool on-column injector--in gas chromatography, a direct sample introduction system which is set at a temperature at or below the boiling point of solutes or solvent on injection and then heated at a rate equal to or greater than the column. Normally used to eliminate boiling point discrimination on injection or to reduce adsorption, or both, on glass liners within injectors. The sample is injected directly into the head of the capillary column tubing or retention gap. 3.1.4 Gram-Schmidt chromatogram--a nonselective summation of total intensity from a spectral scan per unit time which resembles in profile a flame ionization detector chromatogram. 3.1.5 retention gapmin gas chromatography, refers to a deactivated precolumn which acts as a zone of low retention power for reconcentrating bands in space. The polarity of the precolumn must be similar to that of the analytical column. 3.1.6 selective wavelength chromatogram (SWC)--in this test method, refers to a selective chromatogram obtained by summing the spectral intensity in a narrow spectral wavelength or frequency range as a function of elution time which is unique to the compound being quantitated. 3.1.7 uncalibrated aromatic componentmin this test method, refers to individual aromatics for which a calibration is not available and whose concentrations are estimated from the response factor of a calibrated aromatic component. 3.1.8 wall coated open tubular (WCOT)--a type of capillary column prepared by coating or bonding the inside wall of the capillary with a thin film of stationary phase. 4. Summary of Test Method 4.1 A gas chromatograph equipped with a methyisilicone WCOT column is interfaced to a Fourier transform infrared spectrometer. The sample is injected through a cool oncolumn injector capable of injecting a small sample size without overloading the column. 4.2 Calibration is performed using mixtures of specified pure oxygenates and aromatic hydrocarbons on a mass basis. Volume % data is calculated from the densities of the individual components and the density of the sample. Multipoint calibrations consisting of at least five levels and bracketing the concentration of the specified individual aromatics is required. Unidentified aromatic hydrocarbons

1011

tip D 5986 Vapor P h m

present which have not been specifically calibrated for are quantitated using the response factor of 1,2,3,5tetramethylbenzene and summed with the other calibrated aromatic components to obtain a total aromatic concentration of the sample. 4.3 Specified quality control mixture(s) are analyzed to monitor the performance of the calibrated GC/FTIR system.

45

35 20

AJ~oCosnce (mAU) 20

5.1 Test methods to determine oxygenates, benzene, and the aromatic content of gasoline are necessary to assess product quality and to meet new fuel regulations. 5.2 This test method can be used for gasolines that contain oxygenates (alcohols and ethers) as additives. It has been determined that the common oxygenates found in finished gasoline do not interfere with the analysis of benzene and other aromatics by this test method.

15 10

o

successfully. The minimum purity of the carrier gas used iNFRAREDSPECTROFHOTOMETER

i.rtsFeRO.ErtS /

~-'~ t...._J

~

ELI 3TRONiCS

t¢

GAS CHROMATOGRAPH

iNJECTiON

J

VENTI

POnT .......

1 .........

II °yEN

.,e---

FIG. 1

Light-Pipe GC/FTIR System

|

....

|

i.,,|

. . . .

|

. . . .

|

. . . .

|

. . . .

t~

NOTE h Warning--The gasoline samples and solvents used as

reagents such as heptane and toluene are flammable and may be harmful or fatal if ingested or inhaled. Benzene is a known carcinogen. Use with proper ventilation. Safetyglasses and glovesare required while preparing samples and standards. 7.3 Internal Standard--l,2-dimethoxyethane (DME) or deuterated compounds, or both, have been used successfully. A single internal standard such as DME may be used. If other internal standards are used, a narrow selective wavelength range must be determined to generate a SWC which yields no interference from other components in the sample. 7.4 Liquid Nitrogen, supplied from low pressure dewar. Required for cooling of the MCT detector. Dewar may be connected through an electronic solenoid to the MCT cooling reservoir for unattended operation. NOTE 2: Wm'ning--Helium and hydrogen are supplied under high pressure. Hydrogen can be explosive and requires special handling. Hydrogen monitors that automatically shut offsupply to the GC in case of serious leaks are available from GC supply manufacturers.

CELL

)- To Dill Systemlot Fullher Proceuing

....

must be 99.85 mole %. Additional purification using commercially available scrubbing reagents is recommended to remove trace oxygen which may deteriorate the performance of the GC WCOT column. 7.2 Dilution Solvents--n.heptane and methylbenzene (toluene) used as a solvent in the preparation of the calibration mixture. Reagent grade. All at 99 % or greater purity. Free from detectable oxygenates and aromatics which may interfere with the analysis. 7.2.1 Toluene should be used as a solvent only for the preparation of C9+ components and must be free from interfering aromatics.

6.2 FTIR Spectrometer:

7. Reagents and Materials 7.1 Carrier Gas--Helium and hydrogen have been used

~

4000 35OO 30O0 25OO 20OO 1500 Frequency (era-l) FIG. 2 Vapor Phase Spectrum of Benzene

6.1.1 System equipped with temperature programmable gas chromatograph suitable for cool-on-column injections. The injector must allow the introduction of small (for example, 0.1 pL) sample sizes at the head of the WCOT column or a retention gap. An autosampler is mandatory. 6.1.2 WCOT column containing a methylsilicone stationary phase which elutes the aromatic hydrocarbons according to their boiling points. A column containing a relatively thick film of stationary phase, such as 4 to 5 lam, is recommended to prevent column sample overload. 6.2.1 This test method requires a light-pipe GC/FTIR system (Fig. 1). No data have been acquired with matrixisolation or other deposition type systems. 6.2.2 The spectrometer must be equipped with a mercurycadmium-telluride (MCT) detector capable of detecting from at least 4000 cm-I to 550 cm-l. 6.2.3 The lower limit of 550 cm-I is necessary for the accurate determination of benzene. Figure 2 gives an acceptable infrared spectra of benzene.

-

5

6. Apparatus 6.1 Gas Chromatograph:

IR LIGHT~

4

40

5. Significance and Use

is souRcE

S p e c t r u m of Benzene

7.5 Spectrometer Purge Gas, N2 dry air has not been tested, but should be adequate. NOTE 3--The FTIR spectrometer can be protected by installing appropriate filters to remove volatile oils or contaminants that may be present in commercial low quality nitrogen supplies. A liquid nitrogen dewar may be used as a source for the nitrogen purge. 7.6 Standards for Calibration and Identification, all at 99 % or greater purity (Tables 1 and 2). If reagents of high 1012

q~ D 5986 TABLE 2 GC/FTIR Aromatic HydrocarbonsCalibration Components (Calibrated Aromatic Components)

TABLE 1 GC/FTIR Oxygenates Calibration Components Compound Methyl-t-butyl ether (MTBE) Ethyl-t-butyl ether (E'I'BE) Methyl-t-.~yl ether (TAME) Oblsopropyl ether (DIPE) Methanol Ethanol 2-Propan~ t-Butanol t-Propanc~ 2-Butanol Isobutanol 1-Bman~ 1,2-dimethoxyethane(DME) (Internal Standard)

CAS 1634-04-4 637-92-3 994-05-8 106-20-3 67-56-1 64-17-5 67-63-0 75-65-0 71-23-6 15892-23-6 78-83-1 71-36-3 110-71-4

Compound Benzene Methylbenzene Ethylbenzene 1,3-Dlmethylbenzene 1,4-Olmethylbenzene 1,2-Dlme~ylbenzene (1-Methylethyl)-benzene Propyl-benzene l-methyt.3-ethylbenzene 1-rnethyl-4-ethylbenzene 1,3,5.trlmethylbenzene 1.methyl-2-ethylbenzene 1,2,4-trlrnethylbenzene 1,2,3.tdrnethylbenzene Indan 1,4
purity are not available, an accurate assay of the reagent must be performed using a properly calibrated GC or other techniques. The concentration of the impurities which overlap the other calibration components must be known and used to correct the concentration of the calibration components. Because of the error that may be introduced from impurity corrections, the use of only high purity reagents is strongly recommended. Standards are used for calibration as well for establishing the identification by retention time in conjunction with spectral match.

Naphthalene 2-methyl-naphthalene 1-methyl-naphthalene

8. Sampling 8.1 Make every effort to ensure that the sample is representative of the fuel source from which it is taken. Follow the recommendations of Practice D4057 or its equivalent when obtaining samples from bulk storage or pipelines. Sampling to meet certain regulatory specifications may require the use of specific sampling procedures. Consult appropriate regulations. 8.2 Take appropriate steps to minimize the loss of light hydrocarbons from the gasoline sample while sampling and during analyses. Upon receipt in the laboratory chill the sample in its original container to 0 to 5"C (32 to 40*F) before and after a sample is obtained for analysis. 8.3 After the sample is prepared for analysis with internal standard(s), chill the sample and transfer to an appropriate autosampler vial with minimal headspace. Re-chill the remainder of the sample immediately and protect from evaporation for further analyses, if necessary. 9. Calibration Procedure 9. l Preparation of Calibration Standards--Prepare multicomponent calibration standards using the compounds listed in Tables l and 2 by mass according to Practice D 4307. Prepare calibration solutions as described in 9. l to 9.1.4 for each set. Adjust these concentrations, as necessary, to ensure that the concentrations of the components in the actual samples are bracketed by the calibration concentrations. Solid components are weighed directly into the flask or vial. The specified volumes of each calibration component are weighed into 100 mL volumetric flasks or 100 mL septum capped vials. Prepare a calibration standard as follows. Cap and record the tare weight of the 100 mL volumetric flask or vial to 0.1 mg. Remove the cap and carefully add components to the flask or vial starting with the least volatile component. Cap the flask and record the net mass (Wi) of the aromatic component added to 0.1 mg. Repeat the

CAS No. 71-43-2 108-88-3 100-4t -4 108-38-3 106-42-3 95-47-6 98-82-8 103-65-1 620-14-4 622-96-8 108-67-8 611.14-3 95-63-6' 526-73-8 496-11-7 105-05-5 104-51-8 135.01-3 95-93-2 527-53-7 91-20-3 91-57-6 90-12-0

addition and weighing procedure for each component. Similarly add the internal standard and record its net mass (Ws) to 0.1 rag. Store the capped calibration standards in a refrigerator at 0 to 5"C (32 to 40*F) when not in use. NOTE 4 - - M i x all calibration solutions for at least 30 s on a Vortex mixer after preparation or equivalent. Highly precise sample robotic sample preparation systems are available commercially. These systems may be used provided that the results for the quality control reference material (Section 11) are met when prepared in this manner.

9.1. ! Ethers and Alcohols: 9.1.1.1 Three sets of at least six calibration levels each (eighteen total solutions) are prepared bracketing the 0 to 20 volume % range. Set 1: for MTBE, DIPE, ETBE, TAME; Set 2: MeOH, EtOH, 2-PrOH, t-BuOH; and Set 3: I-PrOH, 2-BuOH, i-BuOH, I-BuOH. 9.1.1.2 For each above Set: 1, 3, 5, 10, 15, and 20 mL aliquots of each component are pipetted into respective 100 mL volumetric flasks or vials while accurately recording the masses. For example, for Set 1, into flask one add 1.0 mL MTBE, 1.0 mL DIPE, 1.0 mL ETBE, 1.0 mL TAME; into flask two add 3.0 mL MTBE, 3.0 mL DIPE, 3.0 mL ETBE, 3.0 mL TAME; and so forth. Add the oxygenate in reverse order of their boiling points. The above procedure produces six calibration solutions for each set with the concentrations of each analyte at 1, 3, 5, 10, 15, and 20 volume %. 10.0 mL of DME (internal standard) is then added at constant volumes to each flask or vial while recording its mass. The flasks or vials are then filled to I00 mL total volume with toluene. It is not necessary to weigh the amount of solvent added since the calculations are based on the absolute masses of the calibration components and the internal standard components. 9.1.1.3 For best accuracy at concentrations below 1%, prepare calibration standard sets to bracket the expected concentration. Some of the alcohols are present at low concentrations in gasoline blends. In this case, for example, if the expected analyte concentration is 0.5 volume %, prepare calibration solutions by mass in the range of 0.1 to

1013

lib D 5 9 8 6 1.0 volume %. Furthermore, if the components in Set 3 are all at these low concentrations then for calibration they can be added to Set 2, thus reducing the calibration solutions to Sets 1 and 2. 9.1.2 Benzene, Toluene, Ethylbenzene, Xylenes (BTEX)

(Table 3/Set A): 9.1.2.1 To each of six 100 mL volumetric flasks or vials, add 10.0 mL of DME and record the mass. 9.1.2.2 For ethylbenzene, m, p, and o-xylenes (EX): 1, 3, 5, 7, 9 and 10 mL of each analyte is added to the respective flasks above while accurately recording the masses. 9.1.2.3 For toluene (T): 1, 3, 5, 7, 10, 15 mL aliquots are added to respective flasks above (that is, least concentrated toluene is in solution with least concentrated ethylbenzene and xylenes-EX) while accurately recording the masses. 9.1.2.4 For benzene (B): 0.10 mL, 0.30 mL, 0.50 mL, 1 mL, 2 mL, 3 mL of benzene are weighed into respective 100 mL flasks or vials (that is, least concentrated benzene is in solution with least concentrated TEX above). 9.1.2.5 The flasks or vials are then filled to 100 m L with n-heptane. This procedure generates calibration solutions containing increasing amounts of benzene from 0.1 to 3 volume %, toluene from 1 to 15 volume %, and ethylbenzene and m, p, and o-xylenes each from 1 to 10 volume % with the internal standard (DME) at a constant 10 volume %. 9.1.3 C9 Aromatics (Table 3/Set B): 9.1.3.1 Add 0.5, 1.0, 2.0, 3.0, 5 mL of each of the Cg-aromatics in Table 2 to the respective five flasks or vials (that is, add all of the 0.5 mL concentrations together in flask one, all of the 1.0 mL concentrations to flask two, and so forth) while accurately recording the masses. 9.1.3.2 Add 10.0 mL of DME to each of the five flasks or vials and record the mass of DME. 9.1.3.3 The flasks or vials are then filled to 100 m L with n-heptane. This procedure generates calibration solutions for the C9 aromatics in the range of 0.5 to 5 volume %. TABLE 3

Relative Densities 600F/60*F

Benzene Methylbenzene Ethylbenzene 1,3-Oimethylbenzene 1,4-Dlmethylbenzene 1,2-Dlmethylbenzene (1-Methylethyl)-benzene Prowl-benzene 1-Methyl-3-ethylbenzene 1-Methyl-4-ethylbenzene 1,3,5-Tdmethylbenzene 1-Methyl-2-ethylbenzene 1,2,4-Tdmethylbenzene 1,2,3-Trimethylbenzene Inden 1,4-Diethylbenzene Butytbenzene 1,2-Dlethylbenzene 1,2,4,5-Tetrernethylbenzene 1,2,3,5-Tetramethylbenzene Naphthalene 2-MethyI-Naphthelene 1-Methyl-Naphthalene. Uncelibrated aromatics

0.8845 0.8719 0.8717 0.8687 0.8657 0.8848 0.8663 0.8666 0.8890 0.8657 0.8696 0.8852 0.8802 0.8987 0.9685 0.8663 0.8646 0.8643 0.8918 0.8946 1.000 1.000 1.000 1.000

CalibrationSet Set A Set A Set A Set A Set A Set A Set B Set B Set B Set B Set B Set B Set B Set B Set B Set C Set C Set C Set C Set C Set C Set C Set C .

.

=

where:

Ai = area of aromatic compound "i", and As = area of internal standard. as the y-axis versus the amount ratio amt~: amtt = W~/Ws

Relative Densities and Calibration Procedure for Aromatic Hydrocarbons

Compound

9.1.4 C,o+ Aromatics (Table 3/Set C)." 9.1.4.1 Add 0.5, 1.0, 2.0, 3.0, 4 m L or grams, if solids, of each of the C,o-aromatics in Table 2 to the respective five flasks or vials (that is, add all of the 0.5 mL concentrations together in flask one, all of the 1.0 m L concentrations to flask two, etc.) while accurately recording the masses. 9.1.4.2 Add 10.0 mL of DME to each o f t h e five flasks or vials and record the mass of DME. 9.1.4.3 The flasks or vials are then filled to 100 mL with toluene. This procedure generates calibration solutions for the C,o aromatics in the range of 0.5 to 4 volume %. 9.1.4.4 Ensure that all of the prepared standards are thoroughly mixed and transfer approximately 2 mL of the solution to a vial compatible with the autosampler. Chill the vials until ready for loading on the autosampler. 9.2 GC/FTIR Procedure: 9.2.1 Before initiating the calibration procedure ensure that the GC/FTIR system has been set up according to the manufacturer's instructions. 9.2.2 The WCOT must meet the resolution requirements described in Table 4 when installed in the GC/FTIR system. 9.2.3 Prepare a solution of 0.01 mass % of naphthalene and ensure that it is detected with at least a signal/noise ratio of five. 9.2.4 Sequentially analyze all of the calibration standards. 9.2.5 Table 5 gives suggested operating conditions. 9.3 Calibration Calculations: 9.3.1 After the analyses of the calibration standards is complete, the GC/FTIR is calibrated by generating the selective reconstruction chromatograms for each analyte and the internal standard from the frequency ranges in Table 6. These GC peaks are integrated and calibration curves for each analyte are obtained. 9.3.2 Plot the response ratio rspt: rsp, (Ai/As) (I)

(2)

where: Wi = mass of aromatic compound "i" in the calibration standard, and Ws = mass of internal standard in the calibration standard. as the x-axis to generate calibration curves for each oxygenate and aromatic component in Tables 1 and 2. TABLE 4

Gas Chromatographic WCOT Relolution Requirement Resolution *R" between ethylbenzene and p+m xylene at the 3 mass % level each must be equel to or greater than 1 R ,,

2(t2 - tl)

1.6990,2+ yl)

t2 ,,, retention Ume of p+m xylenes tl - retention Ume of ethylbenzene y2 -, peak width at half height of p+m

xy~rm

yl - peak width at half height ethylbenzene

.

1014

II~) D 5 9 8 6 TABLE 5

GC/FTIR Conditions

TABLE 6

Recommended Conddions

Compound

Gas Chromatography (GC) Column

60 m x 0.53 mm ID, (:If = 5.0 gm polymethylsiloxane

Injector type

cool on-column. A section of deactivated or polymethylalloxanecoated 0.53 mm ID fused silica tubing can be connected between the Injector and the column with a low dead volume union to allow use of an on-column autosempier 0.5 track oven temperature

Injection size ~1) Injector temper-

ature (*C)

Oven temperature Carder gas Cardar gas linear

50ec (0 rain), 2°C/rain to 190"C (0 mln); 30°C/rain to 300°C (1 rain) hydrogen or helium hydrogen: 42 om/s at 300oC

GC/FTIR Interface approximately 300"C

FTIR Spectrometer C~I Detector MCT range Resolution Scan rate Selective absorbance reconstructions

light pipe at 300"C mercury-cadniurn-telluripe (MCT) at least 4000 cm-1 to 550 cm-1 8 cm-1 1 spectrum/s, all data points stored Second difference with function width = 75. A different reconstruction frequency range is used for each analyte (Table). Reference spectra are taken by averaging the first 0.5 min of the chromatogram at which time no compounds alute

9.3.3 Check the correlation r 2 value for each aromatic calibration. The value r: should be at least 0.99 or better and is calculated as follows: (z xy)~ r2 =

Frequencies cm-1

Benzene Methylhenzane Ethylbanzane 1,3-Oimethylbanzane 1,4-Dimethylbanzane 1,2-Dlmethylbanzane (1-Methylethyl)-banzane Propyl-banzane 1-Methyl-3-ethylbanzane 1-Methyl-4-ethylbanzane 1,3,5-Tdmethylbanzane 1-Methyl-2-ethylbanzane 1,2,4-Tdmethylhenzane 1,2,3-Tdmethylbanzene Indan 1,4-Dlethylbanzane n-Butylbenzane 1,2.Diethylbenzane 1,2,4,5-Tetrarnethylbanzane 1,2,3,5-Tetramethytbanzane Naphthalene 2-MethyI-Naphthalane 1-MethyI-Naphthalane Uncalibrated Aromatics Mathyl-t-butyl ether (MTBE) Ethyl-t-butyl ether (ETBE) Methyl-t-amyl ether (TAME) DHsopropyl ether (DIPE) Methanol Ethanol 2-Propanol t-Butanol 1-Propanol 2-Butanol

valoclty (ore/s) Interface temperature (*C)

GC/FTIR Selective Reconstruction Frequencies 670-678 724-732 694-702 687-895 790-798 736-744 695-703 695-703 775-783 807-815 831-839 741-749 801-809 762-770 739-747 825-834 694-702 748-756 863-871 844-852 777-785 803-811 782-790 600-900 A 1205-1213 1199-1207 1185-1193 1122-1130 1055-1063 1052-1060 1141-1149 1207-1215 1056-1064 1128-1136

Isobutanol

1037-1045

1-Butanol 1,3-Dimethoxyethane(DME) (Internal Standard)

3665-3673 1123-1131

'~ Use the calibration curve of 1,2,3,5-tatramethylhenzane at the SWC of 600-900 cm-1 for quantltation of uncalibrateq aromatics. See 12.2.2 and Figs. 4 and 5 for the location and SWCs for each of the uncallbrated compounds.

(3)

(z x2XZ y2)

TABLE7

E x a m p l e o f ~ ~tforPCalculdon

where: x = X~ - .~

(4)

y = Y; - Y

(5)

and

1.0

0.5

-2.0

-1.0

2.0

4.0

1.0

2.0 3.0 4.0 5.0

1.0 1.5 2.0 2.5

-1.0 0.0 1.0 2.0

-0.5 0.0 0.5 1.0

0.5 0.0 0.5 2.0

1.0 0.0 1.0 4.0

0.25 0.0 0.25 1.0

X~ = amt~ ratio data point, X = average values for all (amt~) data points, Y~ = corresponding rsp~ ratio data point, and = average values for all amt, data points. Table 7 gives an example o f the calculation for an ideal data set Xi and Yi. 9.3.4 Linear Least Squares Fit--For each aromatic "i" calibration data set, obtain the linear least squares fit equation in the form:

(rspt)

=

(mi)(amti) + bi

x'-3 !I-1. (~. xy) 2 - 25.0

~: x2 ,- 10.0 1~y 2 - 2.

(z xy)2

r 2 m - r2 -

and

(6)

where:

25.0 - 1.0 (10.0X2.5)

bl =

Y -

m7

(8)

For the example in Table 7:

rsp~

= response ratio for aromatic " I " (y-axis), m; = slope o f l i n e a r equation for aromatic " I " , amt~ = a m o u n t ratio for aromatic " I " (x-axis), and b, = y-axis intercept. The values m, and b, are calculated as follows:

~xy

m, = - -

2; x 2

m~ = 5/10 = 0.5

(9)

and

b, (7) 1015

-- 1.5 - ( 0 . 5 ) ( 3 ) = 0

(10)

Therefore, the least square equation for the above example in Table 7 is:

o sgoe (rsp,) = 0 . 5 ( a m t i ) + 0

(11)

NOTE 5mNormally the b~ term is not zero and may be positive or negative.

9.3.4.1 The calibration response for benzene with a MCT detector may be nonlinear. In the round robin of this test method a linear fit was used for concentrations up to approximately one mass % benzene and a point to point or quadratic fit used for higher concentrations. The region of linearity may vary among instrument types and needs to be determined during calibration. 9.3.5 Y-intercept Criteria--For an optimum calibration, the absolute of the y-intercept b,. must be at a minimum, that is, the calibration curves must not deviate significantly from a y-intercept equal to zero value. A~approaches zero when wi is less than 0.1 mass %. As A~ approaches zero, the equation to determine the mass % aromatics reduces to Eq 12. Therefore, the y-intercept can be tested using Eq 12: w~ = (b,/m,)( Ws/ Ws) I00 % (12) where: wi -- mass % aromatic "I", where wi is <0.1 mass %, Ws= mass of internal standard added to the gasoline samples for the quantitation of the aromatic component "i", g, and Ws= mass of gasoline samples, g. NOTE 6--Since in practice W, and We vary slightly from sample to sample, typical values for these parameters are used to test the y-intercept.

9.3.6 The GC/FTIR system must be recalibrated whenever results of the quality control reference material do not agree within the tolerance levels specified in 11.1.

10. Sample Analysis Procedure 10.1 Add 1.0 mL of internal standard into a 10.0 mL volumetric flask or vial and record the mass (W,.). Add 9.0 mL of gasoline sample to the flask or vial, and record the mass (Ws). The sample/internal standard solution is then mixed 30 s on a vortex mixer and analyzed by GC/FTIR according to the instrument manufacturer's directions using the same conditions as for calibrations. 11. Quality Control Reference Material 11.1 After the calibration has been completed, prepare the quality control reference material outlined in Table 8. Analyze the reference material as described in the sample preparation procedure below. The individual aromatic and total aromatics values obtained must agree within +5 % relative of the values in the prepared reference material (for example, benzene 1.0 + 0.05). If the individual values are outside the specified range verify calibration and instrument parameters, accuracy of the preparation of quality control reference material, and so forth. Do NOT analyze samples without meeting the quality control specifications. 11.1.1 If samples containing oxygenated fuel additives such as ethanol, methyl-t-butylether (MTBE) are also analyzed in addition to conventional oxygenates free gasolines, then several quality control reference materials must be prepared containing the major oxygenated additives at levels found in gasoline samples. l l.2 Analyze the quality control reference materials be1016

TABLE 8

Compoeition of Quality Control Reference Matedel for Aromatic Hydrocarbon A n a l y l l e 4 Compound

Concentration (mass ~,)

n-Hexane n-Heptane n-Octane n-Decane n-Dodecane 2,2,4-Tdmethylpentane Benzene Toluene 1,3-Din'~thylbenzens 1,2-DImethylbenzene Ethylbenzene 1,2,4-Trlmethylbenzene 1,2,4,5-TeUlmethylbenzene Total aromatics

12 17 17 12 5 12 1 9 3 3 3 3 3 25

A If sample contains oxygenates, then Include the major oxygenate(s) in the QC

sample.

fore every batch of samples. Bracket the samples with the reference material. If the reference material does not meet the specifications in 11.1, the samples analyzed immediately preceding the reference material are considered suspect and should be rerun. 12. Calculations 12.1 Oxygenates: 12.1.1 After identifying the various oxygenates, measure the areas of each oxygenate peak and that of the internal standard. Figure 3 gives the elution order of the various oxygenates. From the least squares fit calibrations, Eq 13, calculate the absolute mass of each oxygenate components (Wt) in grams in the gasoline samples using the response ratio (rspi) of the areas for the oxygenates components to that of the internal standard as follows:

12.1.2 To obtain mass % (wo) results for each oxygenate: We = (w,/w.)(lOO ~) (14) where: Ws = mass of gasoline sample. 12.1.3 Mass % Oxygen--To determine the oxygen content of the fuel, sum the mass of oxygen contents of all oxygenated components determined above according to the following equation: Wot =

Z (w°XI6XN')

M,

(15)

where: Wo = mass % of each oxygenates, Wo, -- total mass % oxygen in the fuel, M, -- relative molecular mass of the oxygenate as given in, Table 9, 16.0 = atomic mass of oxygen, and Ni = number of oxygen atoms in the oxygenate molecule. 12.1.4 If the volumetric concentration of each oxygenate component is desired, calculate the volumetric concentration according to Eq 16: v i = w,(D//D,)

where:

(16)

~

D 5986

5~ (Wt/Wt) of Each Oxygenate In Fuel 1250 - 1000 cm-1 Reconstrusted Chromatogram 400 350

B

300 250 200

3: O

,h

.~

3

4

150 100 50

I

2

5

6

7

8

9

10

11

12

13

T i m e (Min.)

FIG. 3

TABLE 9

5% (wt/wt) of Each O x y g e n a t e d In Fuel 1250-1000 cm-1 Reconstructed C h r o m a t o g m m

Relative Densities and Molecular M a s s e s of Oxygenates

Compound Methyl-t-butyl ether (MTBE) Ethyl-t-butyl ether (ETBE) Methyl-t-amyl ether (TAME) DI-isopropyl ether (DIPE) Methanol Ethanol 2-Propanol t-Butano~ 1-Propanol 2-Butanol

Isobutenol 1-Butanol 1,3-dimethoxyethene (DME)

Relative Densities 60°F/60°F

Relative Molecular Mass

0.7460 0.7452 0.7758 0.7300 0.7963 0.7939 0.7899 0.7922 0.8080 0.8114 0.8058 0.8137 0.8720

88.2 102.18 102.18 102.18 32.04 46.07 60.09 74.12 60.09 74.12 74.12 74.12 ...

TABLE 10

v~. -- volume % of each oxygenate to be determined, Dr = relative density at 15.56°C (60"F) of the individual oxygenates as found in Table 9, and Df -- relative density of the fuel under study as determined by Practice D 1298 or Test Method D 4052. 12.2 Aromatic Hydrocarbons: 12.2.1 After identifying the various calibrated aromatic hydrocarbons in Table 2, including benzene, (Fig. 4) measure the areas of each aromatic peak at the selective reconstruction frequency in Table 6 and that of the DME internal standard. From the least squares fit calibrations, Eq 13, calculate the absolute mass of each aromatic components (W,.) in grams in the gasoline samples using the response ratio (rsp~) of the areas for the aromatic components to that of the internal standard. 12.2.2 Uncalibrated Aromatic Components (3.1.5)--The calibration components in Table 2 may not account for all of the aromatic hydrocarbons present in the gasoline sample. For the uncalibrated components (Figs. 4 and 5) follow the chromatographic fingerprint in Fig. 5 to selectively quanti-

Range and Repeatability

Component

Range (Mass/Volume ~)

Repeatability

Aromatics, volume % Aromatics, mass ~ Benzene, volume ~ Benzene, mess ~ Toluene, volume ~ Toluene, mass ",o 1-Butanol, mass • 1-Propenol, mass "/o 2-Butenol, mass • 2-Propenol, mass ~ DIPE, mass • ETBE, mass • Ethanol, mass ~ Isobutenol, mass ~ Methanol, mass ~ MTBE, mass • TAME, mass ~ ten-Butanol, mass ~

13-41 16-49 0.1-2 0.1-2 2-9 2-10 0.5-1 0.2-1 0.6-3 1-2 0.3-2 1-18 1-12 0.1-2.0 1-5 1-15 1-18 1-2

0.55 0.23Xo-aaaa 0.0099 (X + 0.6824) 0.012 (X + 0.48) 0.10 0.057 0.082 0.050 0.081 0.073 0.026XoA 0.066Xo.s 0.052X °-s 0.057 0.035 0.032X °,5 0.088X°'e 0.051

tate each uncalibrated compound using the specified SWC in Fig. 4. Use a SWC of 600 to 900 cm- l as a guide in detecting the uncalibrated aromatics (Fig. 4 was obtained with a SWC of 600 to 900 cm-l). Use the least square linear fit of 1,2,3,5-tetramethylbenzene obtained using the SWC of 600 to 900 cm-l for the quantitation of the uncalibrated aromatic components. NOT~ 7--Consider all peaks between the retention time of indan and the end of the 600 to 900 cm-I chromatogram (end of GC analysis time) as uncalibrated aromatic components except for the calibrated components in Table 2.

12.2.3 To obtain mass percent (Wa) results for each aromatic hydrocarbon, including uncalibrated aromatics: wa ffi (WJWsXIO0 %) (17) where: W s = mass of gasoline sample. 12.2.4 T o obtain the mass %

1017

of the total aromatic

q~ D 5 9 8 6 T A B L E 11

R a n g e and

Reproducibility

Component

Range (Mass/Volume %)

Aromatics, volume % Aromatics, mass % Benzene, volume % Benzene, mass % Toluene, volume % Toluene, mass % 1-Butanol, mass % 1-Propanol, mass % 2-Butanol, mass % 2-Propanol, mass % DIPE, mass % ETBE, mass % Ethanol, mass % Isobutanol, mass % Methanol, mass % MTBE, mass % TAME, mass % tert-Butanol, mass %

13-41 16-49 0.1-2 0.1-2 2-9 2-10 0.5-I 0.2-I 0.6-3 1-2 0.3-2 1-18 1-12 O.1-2.0 1-5 1-15 1-18 1-2

ponent, including the volume percent of the uncalibrated components: v, = z v, (20)

Reproduolbility 1.65 0.69Xo.~aa 0.054 (X + 0.68) 0.063 (X + 0.48) 0.23 0.20 0,12 0.078 0.45 0.10 0.066Xo ( 0.19X°,s 0,1 I X °.s 0.12 0.45 0.17Xo.s 0.15Xo.e 0.18

12.2.8 Report results to nearest 0.I volume % for total aromatics and to nearest 0.01 volume % for benzene.

concentration Wt, sum the mass % of each aromatic component, including the mass percent of the uncalibrated components: w, ffi ~ wo

(18)

12.2.5 Report results to nearest 0.1 mass % for the total aromatics and to nearest 0.01 mass % for benzene. 12.2.6 If the volumetric concentration of each aromatic component is desired, calculate the volumetric concentration according to Eq 19: vl = wa(Df/Di)

(19)

where: v, = volume % of each aromatic to be determined, D~ = relative density at 15.56°C (60°F) of the individual aromatics as found in Table 3, and Df = relative density of the fuel under study as determined by Practice D 1298 or Test Method D 4052. 12.2.7 To obtain the volume % of the total aromatic concentration V,, sum the volume % of each aromatic com-

1018

13. Precision and Bias 4 13.1 Precision--The precision of this test method as determined by a statistical examination of interlaboratory test results is as follows: 13.1.1 Repeatability--The difference between successive results obtained by the same operator with the same apparatus under constant operating conditions on identical test materials would, in the long run, in the normal and correct operation of the test method exceed the following values only in one case in twenty: where: X = the mean mass or volume % of the component. 13.1.2 Reproducibility--The difference between two single and independent results obtained by different operators working in different laboratories on identical test materials would, in the long run, in the normal and correct operation of the test method exceed the following values only in one case in twenty: where: X = the mean mass or volume % of the component. 13.2 Bias--Since there is no certified reference material suitable for determining the bias for the procedures in this test method bias cannot be determined.

14. Keywords 14.1 aromatics; benzene; gas chromatography; GC/IR; gasolines; oxygenates; toluene 4 Supporting data is available from ASTM Headquarters in the form of a research report. Request RR:D02-1390. The volume % repeatability and reproducibility were determined for constant fuel densities given to round robin participants.

@ D soas £STIMATED AROMATICS' RECONSTRUCTION FREQUENCIES

Naphthalene

.00-

.04-

5 .02-

II /^ /

~~ ,".Z ~ . .~

I//

eel,,,

II

I

Ill

O-

i ~J

i

i

~

H ¢J

-,t,.,

,,

=

~-

¢j

smq

-'

i

~

¢J

e

e

=

o

®

,'-

,'~

,~

p.q

r.,.

r"

~

t

--.

~/

,

=

~

,~

-~

~

~

~

i

-~

~

¢J

.=a,

z,

r "~

.~

J

70

60

minutes

FIG. 4 Expanded Selective Wavelength Chmmatogram (602-899 cm-1) of Total Aromatics

1019

f[~ D 5986

EXPANDED SELECTIVE WAVELENGTH CHROMATOGRAM (602-899 cm-l) of TOTAL AROMATICS Benz~ne

.04-

Toluene

.03 -

.02A Q [--

!

U I

e8 dB

m Q

dg

.01

!!

| um

~

,o

~

A~-

1 . . . . . .

:~

MINUTES

SWC of 602-899 cm-1 FIG. 4

Expanded 8elective Wavelength Chromatogram (602-899 cm-1) of Total Aromatics (Continued)

1020

=, N m

~

.04-

D 5986

Naphthalene

!

!~" iadtut

2.M-Naphtbxlene

t t_~OJ

.111-

I

U

I-M-Naphthalene

,t/ ll~;~ ~ ~

./

,le~.

,

O"

l.M.3-n-Pr-Benzcne

C4-nenzencs

u

M

70

MINUTES

SWC of 602-899 cm-1 FIG. 5

Estimated Aromatics' Reconstruction Frequencies

1021

@ D s9ss ESTIMATED AROMATICS' RECONSTRUCTION FREQUENCIES

761-769 cm-I .01-

.016" wq

q

B"

.01-

4 a

E

.006-

i

r~

o-

~4

60

.

minutes FIG. 5

Estimated Aromatics' Reconstruction Frequencies (Continued)

1022

60

i[~i~ D 5986 ESTIMATED AROMATICS' RECONSTRUCTION FREQUENCIES .X124-TM-Benzene

,04-

! 123-TM-Benzene

Indan

.02-

¢~

¢',1

U&

S

0 _'~

4~

40

]

4~

4~

minutes FIG. 5 Estimated Aromatics' Reconstruction Frequencies (Continued)

1023

80

(1~) D 5986 The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted In connection with any item mentioned In this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and If not revised, either reepproved or withdrawn. Your comments are Invited either for revision of this standard or for addltlonal s ~ and Ih(xlld be eddtv',.ssed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend. If you feel that your comments have not received 8 fair heedng you should maka your views known to the ASTM Committee on Standards, 100 Barr Harbor Drive, West Conshohockan, PA 19428.

1024

(~]~

Designation: D 6069 - 96 Standard Test Method for Trace Nitrogen in Aromatic Hydrocarbons by Oxidative Combustion and Reduced Pressure Chemiluminescence Detection 1 This standard is issued under the fixed designation D 6069; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (~) indicates an editorial change since the last revision or rcapproval.

OSHA Regulations, 29 CFR, paragraphs 1910.1000 and 1910.12005

1. Scope 1.1 This test method covers the determination of total nitrogen (organic and inorganic) in aromatic hydrocarbons, their derivatives and related chemicals. 1.2 This test method is applicable for samples containing nitrogen from 0.2 to 2 mgN/kg. For higher nitrogen concentrations refer to Test Method D 4629. 1.2.1 The detector response of this technique within the specified scope of this test method is linear with nitrogen concentration. 1.3 The following applies to all specified limits in this test method: for purposes of determining conformance with this test method, an observed value or a calculated value shall be rounded off "to the nearest unit" in the last right-hand digit used in expressing the specification limit, in accordance with the rounding-off method of Practice E 29. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements, see Section 9.

3. Terminology 3.1 Definitions." 3. I. 1 reduced pressure chemiluminescence--a chemical reaction at pressure less than 760 mm mercury (Hg) in which light is emitted. 3.1.2 oxidative pyrolysis--a process in which a sample under goes combustion in an oxygen rich environment at temperatures greater than of 650"C. 3.1.2.1 Discussion--Organic compounds pyrolytically decompose to carbon dioxide, water and elemental oxides.

2. Referenced Documents

2.1 A S T M Standards: D 1555 Test Method for Calculation of Volume and Weight of Industrial Aromatic Hydrocarbons2 D 3437 Practice for Sampling and Handling Liquid Cyclic Products 2 D4629 Test Method for Organically Bound Trace Nitrogen in Liquid Petroleum Hydrocarbons By Syringe/ Inlet Oxidative Combustion and Chemiluminescence Detection a E 29 Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications4 E 691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method 4 2.2 Other Documents: 1 This test method is under the jurisdiction of ASTM Committee D-16 on Aromatic Hydrocarbons and Related Chemicals and is the direct responsibility of Subcommittee DI6.0E on Instrumental Analysis. Current edition approved Dee. 10, 1996. Published February 1997. 2 Annual Book of ASTM Standards, Vol 06.04. 3 Annual Book of A S T M Standards, Vol 05.02. 4Annual Book of ASTM Standards, Vol 14.02.

4. Summary of Test Method 4.1 A specimen is introduced into a gas stream, at a controlled rate, and carried into a high temperature furnace (>900"C) where an excess of oxygen is added. Pyrolysis converts organic material in the specimen to carbon dioxide and water. Organic nitrogen and inorganic nitrogen compounds, present in the specimen, are converted to nitric oxide (NO). Nitric oxide reacts with ozone in the detector producing nitrogen dioxide molecules in an excited state. As the excited nitrogen dioxide molecules relax to ground state, light is emitted. This light is detected by a photomultiplier tube with the resulting signal proportional to the concentration of nitrogen in the sample. Operating the detector at a reduced pressure, lowers the probability of the excited nitrogen dioxide molecules colliding with other molecules before it under goes chemiluminescence. Thus, reduced pressure provides improved sensitivity and lower noise. 5. Significance and Use 5.1 This method has been prepared to detect and quantitare nitrogen-containing compounds such as N-formylmorpholine (4-formylmorpholine, Chemical Abstract Service numbers (CAS) No. 250-37-6) or l-methyl-2-pyrrolidinone (NMP) (CAS) No. 872-50-42 at a concentration of 1.0 mgN/kg or less in aromatic hydrocarbons used or produced in manufacturing processes. These nitrogen-containing compounds are undesirable in the finished aromatic products and may be the result of the aromatic extraction process. This test method may be used in setting specifications for determining the total nitrogen content in aromatic hydrocarbons. 5 Available from the Superintendent of Documents, U.S. Government Printing Office, Washington, DC 20402.

1025

~

D 6069

NOTE l--Virtually all organic and inorganic nitrogen compounds will be detected by this technique.

cupric oxide (CuO) or Platinum (Pt)) may be packed into the pyrolysis tube to aid in oxidation efficiencies (see manufacturer's recommendations).

5.2 This technique will not detect diatomic nitrogen and it will produce an attenuated response when analyzing compounds (that is, s-triazine and azo compounds, etc.) that form nitrogen gas (N2) when decomposed. 5.3 This test method requires the use of reduced pressure at the detector. Loss of vacuum or pressure fluctuations impact the sensitivity of the detector and the ability to determine nitrogen concentrations less than 1 mg/kg.

8. Reagents

8.1 Purity of ReagentsmReagent grade chemicals shall be used in all tests. It is intended that all reagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, 6 where such specifications are available, unless otherwise indicated. Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination. 8.2 Inert GasnEither argon (Ar) or helium (He) may be used. The purity should be no less than 99.99 mol %. 8.3 Oxygen GasnThe purity should be no less than 99.99 mol %. 8.4 Solvent~The solvent chosen should be capable of dissolving the nitrogen containing compound used to prepare the standard and if necessary the samples. The solvent of choice should have a boiling point similar to the samples being analyzed and it should contain less nitrogen than the lowest sample to be analyzed. Suggested possibilities include, but are not limited to: toluene, methanol, tetrahydrofuran, /so-octane.

6. Interferences

6.1 Chlorides, bromides, and iodides can interfere if any one or all of these elements are present in a sample in concentrations greater than 10 % by total weight of halogen in the sample. 6.2 Moisture produced during the combustion step can interfere if not removed prior to the detector cell. 7. Apparatus

7. ! Pyrolysis Furnace--A furnace capable of maintaining a temperature sufficient to volatilize and pyrolyze the sample and oxidize organically bound nitrogen to NO. The actual temperature(s) should be recommended by the specific instrument manufacturers. 7.2 Quartz Pyrolysis TubenCapable of withstanding 900 to 1200"C. 7.2.1 Quartz Pyrolysis Tube~The suggested maximum temperature for a quartz pyrolysis tube is 1200"C. Samples containing alkali-metals (elements from the Periodic Group IA (that is, Na, K, etc.)) or alkaline earths (elements from the Periodic Group IIA (that is, Ca, Mg, etc.)) will cause quartz to devitrify (that is, become milky white and brittle). 7.3 Chemiluminescent DetectornCapable of operation at reduced pressures (less than 760 mm mercury) and able to measure light emitted from the reaction between NO and ozone. 7.4 Microlitre Syringe~Capable of delivering from 5 to 50 laL of sample. Check with the instrument manufacturer for recommendations for specific sample needs. 7.5 Constant Rate Injector System (Optional)~If the sample is to be introduced into the pyrolysis furnace via syringe, a constant rate injector should be used. 7.6 Boat Inlet System (OptionaO~If the instrument is equipped with a boat inlet system, care must be taken to ensure the boat is sufficiently cooled between analyses to prevent the sample from vaporizing as it is injected into the boat. The sample should start vaporizing as it enters the furnace. It is critical that the sample vaporize at a constant and reproducible rate. This type of inlet system offers advantage when the sample is viscous or contains heavy components not volatile at temperatures of approximately 300"C, or for samples that contain polymers or high concentrations of salts thfit could result in plugging of the syringe needle. 7.7 Automatic Boat Drive System (Optional)--If the instrument is equipped with a boat inlet system, a device for driving the boat in to the furnace at a controlled and repeatable rate may improve data repeatability and reproducibility. 7.8 Oxidation Catalyst (Optional)--Catalyst (that is,

Note 2--A quick screening can be conducted by injecting the solvent and sample once or twice and comparing relative area counts. 8.4.1 SolventnToluene, relative density at 60*F/60*F 0.8718 (see Test Method D 1555). 8.5 Nitrogen Stock Solution, 1000 ~tg N/mL~Prepare a stock solution by accurately weighing, to the nearest 0. i mg, approximately 707.7 mg of l-methyl-2-pyrrolidinone (NMP) (CAS No. 872-50-4) into a 100-mL volumetric flask. Fill to volume with solvent as follows: ~tg N/mL = exact weight of NMP (mg) × 14.0 x 1000 (p.g/mg) (1) 100 mL x 99.1 where: 14.0 = the atomic weight of nitrogen, and 99.1 = the molecular weight of NMP. 8.6 Nitrogen Working Standard Solutions, 1.0 and 2.0 pg N/mL--The working standards are prepared by dilution of the stock solution with the solvent. Prepare a 100-~tg N/mL standard by accurately pipetting 10 mL of stock solution into a 100-mL volumetric flask and diluting to volume with solvent. This standard is further diluted to 1.0 and 2.0-~tg N/mL by accurately pipetting 1 mL of the 100 I~g-N/mL standard into a clean 100-mL volumetric flask and pipetting 2 mL of the 100-lag N/mL standard into a different clean 100-mL volumetric flask and diluting each to volume with solvent. 6 Reagent Chemicals, American Chemical Society Specifications, American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed by the Arnerican Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.

1026

(~ D 6069 NOTE 3--Working standards should be prepared on a regular basis depending upon the frequency of use and age. Typically, standards have a useful life of about 3 months. 8.8 Cupric Oxide (CuO) or Platinum (Pt)--May be used as an oxidation catalyst, as recommended by the instrument manufacturer. 8.9 Quartz Wool--May be needed if recommended by the instrument manufacturer.

13. Procedure 13.1 Sample sizes from 5 to 50 laL are acceptable. Although, at the concentration range from 0.2 to 2 lag N/mL, it is recommended that the same size sample be used for all standards and samples analyses. NOTE 4--When an organic sample is injected into the pyrolysis furnace a pressure wave is formed. The initial flash vaporization forms a positive pressure pulse, thus decreasing detector sensitivity. After pyrolysis of the organic material in the high-temperature furnace a reduced pressure pulse is formed, resulting in increased detector sensitivity. Thus, maintaining the same sample size for all injections (that is, samples and standards) will improve repeatabilityand reproducibility. As mentioned in 8.4, Solvent, using a solvent with a boiling point similar to that of the sample being analyzed is generally recommended.

9. Hazards

9.1 Consult current OSHA regulations, suppliers' Material Safety Data Sheets, and local regulations for all materials used in this test method. 9.2 High temperature is employed in this test method. WarningmExtreme care should be exercised when using flammable materials near the pyrolysis furnace.

13.1.1 Always flush the syringe several times with the material to be injected. To prevent contamination do not return the first couple of flushes back into the specimen bottle. 13.1.2 If the instrument is equipped with a pyrolysis tube for direct syringe injection, see 13.2. If the instrument is equipped with a boat inlet system, see 13.3. 13.2 Fill syringe to approximately 1.5 times the volume to be injected (that is, to inject 10 laL, fill a 25-laL syringe with 15 to 20 txL of sample or standard), taking care not to pull air bubbles into the syringe with the sample. With the syringe needle pointed up, push the plunger in to the desired volume, tap the last drop off the needle point, and pull the plunger back until air can be seen in the syringe barrel.

10. Sample Handling

10.1 Collect the samples in accordance with Practice D 3437. 10.2 To preserve sample integrity (consistency) and prevent the loss of volatile components, which may be in some samples, do not uncover samples any longer than necessary. Analyze specimen as soon as possible after transferring from the sample container to prevent loss of nitrogen or contamination. 10.3 Since this procedure is intended for trace level contamination, care must be taken to ensure the containers used for the sample, the specimen, and the working standard do not alter the sample results.

NOTE 5--The inherent accuracy of this technique is dependent upon the ability of the analyst to repeatability inject the same volume for each injection. Air bubbles lodged between the syringe plunger and the specimen will result in variable specimen volumes. If bubbles persist, try cleaning the syringe with a different so!vent or try inserting the needle into a septum and gently putting pressure on the syringe plunger (this may cause persistent bubbles to break free). NOTE 6--If the detector response continuously increases or decreases, this is indicative of contamination. If this occurs, continue injecting the specimen until the detector signal shows a typical variance.

11. Instrument Assembly and Preparation

11.1 Install the instrument in accordance with manufacturer's instructions. See Appendix X I for typical set-up parameters. 11.2 Adjust gas flows and pyrolysis temperature(s) to the operating conditions as recommended by the manufacturer. 11.3 The actual operation of injecting a sample will vary depending upon the instrument manufacturer and the type of inlet system used (see 7.5 through 7.8). 12. Calibration and Standardization

12.1 Prepare the working calibration standards using the stock solution as described in 8.5 and 8.6. 12.1.1 Before injecting a standard or blank, refer to procedures (see Section 13, Procedure), to ensure proper technique for either the direct injection system or the boat inlet system. 12.2 A calibration based on the difference between two gravimetrically prepared standards works well within the limited scope of this procedure. This type of calibration can be used to quantitate nitrogen at the 1.0 ppm (wt/wt) concentration or to determine pass/fail compliance. Two standards are prepared with concentrations that differ by the target specification. Thus, for a 1.0 ppm nitrogen (wt/wt) maximum specification, prepare two standards that differ in concentration by 1.0 ppm (that is, 2.0 lag-N/mL and a 1.0 lag-N/mL standard). 12.2.1 Each standard should be injected in triplicate and the integrator counts averaged and recorded.

13.2.1 Insert the syringe needle through the inlet septum as far as it will go (the syringe barrel should be touching the septum). Allow the residual sample in the needle to burn-off. When the instrument returns to a stable baseline, zero or clear the detector display and inject the specimen or standard at a constant rate of 0.5 to 1.0 ~tL/s. 13.2.2 If an autosampler is used the detector will be automatically zeroed prior to injection. 13.2.3 Repeat 13.2 analyzing each standard and sample in triplicate. Average the three results for each standard or sample and record the results. 13.3 With the boat inlet system, a specimen is injected into a cool boat and the boat carded into the pyrolysis furnace. Before analyzing standards or samples introduce the boat into the furnace to burn-off any possible contamination. 13.3.1 Fill the syringe as described in 13.2. Inject the standard or specimen into the cooled boat. Move the boat containing the specimen into the furnace at a controlled and repeatable rate.

1027

NOTE 7--The boat may be stopped at the furnace inlet to permit evaporation, if a controlled combustion is necessary. Although, if the boat is stopped, it must then be stopped at the same place and for the same length of time for all analyses (see Notes 4, 5, and 6).

(~ O 6069 TABLE 1

TABLE 2

Repeatability and Reproducibility A

Nitrogen Concentration, mg/kg

Repeatability

Reproducibility

0.09 0.15 0.19

0.25 0.26 0.34

0.32 0.60 0.88

A Repeatability and Reproducibility determined at the 95 • confidence level.

13.3.2 Repeat 13.3 analyzing each sample, or standard in triplicate. Average the three results for each sample and record the results. 14. Calculation 14.1 Calculate the concentration of nitrogen as follows: Nitrogen, mg/kg =

I~. x (C,,d2 -- C=d,) X V~,d

(2)

(Istd2-- Istdl) X Vsx X Vsx

where: Isx = detector response of sample, integration counts, Istd2 ---~ highest standard's average detector response, integration counts, Istd~ = lowest standard's average detector response, integration counts, Cstd2 = concentration of higher standard, ~tg N/mL, Cstd~ = concentration of lower standard, lag N/mL, Dsx = density of the sample, g/mL, V~, = volume of sample injected, laL, and V=d = volume of standard solution injected, laL. 15. Precision and Bias 15.1 Precision--The following criteria, conducted under the guidelines of Practice E 691, should be used to judge the acceptability (95 % probability) of the results obtained by this test method. The criteria were derived from a inter-

1028

Estimated Bias

Solvent

Nitrogen Spike, mg N/kg

Average of 10 Laboratories Nitrogen Results Based on the I L S , mg N/kg

Xylene Xylene Xylene

0.32 0.60 0.88

0.32 0.60 0.87

Absolute Difference 0.00 0.00 0.01

laboratory study between ten laboratories. Standards and samples were analyzed in duplicate on the same day by a single operator. Each analysis represented triplicate injections. 15.1.1 Repeatability--Results within laboratory results by the same operator with the same equipment over the shortest practicable period of time should not be considered suspect unless they differ by more than the amount shown in Table 1. 15.1.2 Reproducibility--Results submitted by two laboratories should not be considered suspect unless they differ by more than the amount shown in Table 1. 15.2 Bias--Systematic error that contributes to a difference between the mean and an accepted reference value. Since all organic solvents can contain nitrogen, an absolute statement of bias could not be determined from this study. Although, an estimate of bias was determined by spiking a single solvent (xylene) with three different concentrations of nitrogen. These three spiked samples were then analyzed as unknowns in the intedaboratory study (see Table 2). 16. Keywords 16.1 chemiluminescence; nitrogen

~t~r~ D 6069

APPENDIX (Nonmandatory Information) Xl. TYPICAL S E T - U P C O N D I T I O N S X I. 1 Table XI.I illustrates two instrument's parameters and settings. TABLE X1.1

Typical Set-Up Conditions A,B

Instrument 1 Parameters

Instrument 1 Seffinga

Syringe Drive Rate for Direct Injection

(700-750) 1 i~L/second

Boat Drive Rate for Boat Inlet

(700-750) 140-160 mm/mln

Furnace Temperature

1050 + 25°C

Furnace Oxygen Flowmeter Setting

(3.8-4.1) 450-500 cc/mln

Inlet Oxygen Flewmeter Setting

(0.4-0.8) 10-30 cc/min

Inlet Carrier Flowmeter Setting

(3.4-3.6) 130-160 co/mtn

Ozone Oxygen Flowmeter Setting

(1.5-1.7) 35-45 cc/min

Pyro-tube Back Pressure

1-2.5 psi

Gain

High

Attenuation

50

Sample Size

20 p.L

Instrument 2 Parameter= Automatic Boat Control

Instrument 2 Seffinga 1 Fuc FWD 140Spaed 10 2 Fuc FWD 285 Speed 05 5 Fuc 6 Fuc AFuc

Furnace Temperatures Inlet Catalyst

6000C 950°C

Gas Flow Setting Main Oxygen Inlet Oxygen Inlet Argon

400 cc/min 0.4 L/rain 0.4 L/min

Range

Time 30 Time 30 Time 30 Time 90 Time 60

Low

Attenuation

2

Sample Size

20 IlL

A The sole source of supply of the apparatus for Instrument 1, Antek Model 7000 known to the committee at this time is Antek Instruments, Inc., Houston, TX. If you are aware of altemative suppliers, please provide this information to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, "which you may attend." a The sole source of supply of the apparatus for Instrument 2, Mitsublshi Model TN-10 known to the committee at this time is COSA Instrument Corp., Norwood, NJ. If you are aware of alternative suppliers, please provide this information to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, "which you may attend." The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and ff not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 100 Barr Harbor Drive, West Conshohocken, PA 19428.

1029

~[~ Designation:D6144-97 Standard Test Method for Analysis of AMS ( -Methylstyrene) by Capillary Gas Chromatography 1 This standard is issued under the fixed designation D 6144; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (e) indicates an editorial change since the last revismn or reapproval.

1. Scope 1.1 This test method covers the determination of the purity of AMS (oL-methylstyrene) by gas chromatography. 1.2 This test method has been found applicable to the measurement of impurities such as cumene, 3-methyl-2cyclopentene-l-one, n-propylbenzene, tert-buytlbenzene, secbutylbenzene, cis-2-phenyl-2-butene, acetophenone, 1-phenyl1-butene, 2-phenyl-2-propanol, and trans-2-phenyl-2-butene, which are common to the manufacturing process of AMS. The limit of detection for these impurities is 0.01 wt %. 1.3 The following applies to all specified limits in this test method: tbr purposes of determining conformance with this test method, an observed value or a calculated value shall be rounded off "to the nearest unit" in the last right-hand digit used in expressing the specification limit, in accordance with the rounding-off method of Practice E 29. 1.4 This Test Method does not purport to address all the sqfety concerns, if any, associated with its use. It is the responsibility of the user of this Test Method to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements, see Section 8.

2. Referenced Documents 2.1 ASTM Standards: D 3437 Practice for Sampling and Handling Liquid Cyclic Products 2 D4790 Terminology of Aromatic Hydrocarbons~and Related Chemicals 2 E 29 Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications 3 E 355 Practice for Gas Chromatography Terms and Relationships 3 E 1510 Practice for Installing Fused Silica Open Tubular Columns in Gas Chromatographs 3 2.2 Other Document:

t This test method is under the jurisdiction of ASTM Committee D-16 on Aromatic Hydrocarbons and Related Chemical and is the direct responsibility of DI6.0Hon Styrene, Ethylbenzene, and C and C Aromatic Hydrocarbons. Current edition approved June 10, 1997 Published August 1997. 2 Annual Book of ASTM Standards', Vol 06.04. 3 Annual Book of ASTM Standards, Vol 14.02.

1030

OSHA Regulations, 29CFR, paragraphs 1910.1000 and 1910.12004 3. Terminology 3.1 See Terminology D 4790 for definition of terms used in this test method.

4. Summary of Test Method 4.1 A known amount of internal standard is added to a sample of AMS. The prepared sample is mixed and analyzed by a gas chromatograph (GC) equipped with a flame ionization detector (FID). The peak area of each impurity and the internal standard is measured and the amount of each impurity is calculated from the ratio of the peak area of the internal standard versus the peak area of the impurity. Purity by GC (the AMS content) is calculated by subtracting the sum of the impurities from 100.00. Results are reported in weight percent. 5. Significance and Use 5.1 This test method is suitable for setting specification on the materials referenced in 1.2 and for use as an internal quality control tool where AMS is produced or is used in a manufacturing process. It may also be used in development or research work involving AMS. 5.2 This test method is useful in determining the purity of AMS with normal impurities present. If extremely high boiling or unusual impurities are present in the AMS, this test method would not necessarily detect them and the purity calculation would be erroneous. 6. Apparatus 6.1 Gas Chromatograph--Any instrument having a flame ionization detector that can be operated at the conditions given in Table 1. The system should have sufficient sensitivity to obtain a minimum peak height response for 0.01% n-octane of twice the height of the signal background noise. 6.2 Columns--The choice of column is based on resolution requirements. Any column may be used that is capable of resolving all significant impurities from AMS and the internal standard. The column described in Table 1 has been used successfully. Unless the analyst can be sure of peak identity

4 Available from the Superintendent of Documents, U.S. Government Printing Office, Washington, DC 20402.

~'~

D 6144

TABLE 1 Instrumental Parameters Detector Injectton Port Column A: Tubing Stationary phase Fdm thtckness, pm Length, m Dmmeter, mm

conditioning the column into the chromatograph and adjusting the instrument to the conditions described in Table 1 allowing sufficient time for the equipment to reach equilibrium. See Practice E 1510 for more information on column installation. See Practice E 355 for additional information on gas chromatography practices and terminology.

flame ionization capillary sphtter fused sdlca crosshnked methylsilicone 1.0 60 0.25

11. Procedure

Temperatures' Injector, °C Detector, °C Oven, °C

11.1 Into a 100-mL volumetric flask, add 100 pL of n-octane to 99.90 mL of AMS. Mix well. Assuming a density of 0.704 for n-octane and 0.910 for AMS, the resulting n-octane concentration will be 0.0774 weight %. 11.2 Inject into the gas chromatograph, an appropriate amount of sample as previously determined according to 6.1 and start the analysis. 11.3 Obtain a chromatgram and peak integration report. Fig. 1 illustrates a typical analysis of AMS using Column A and conditions listed in Table 1.

250 250 125

Carrier gas

hehum

Flow rate, mls/mm

2

Split ratio

70 1

Sample stze, pl

1.0

(for example by gas chromatography-mass spectrometry (GCMS)), the use of the column in Table 1 is strongly recommended. 6.3 Recorder--Electronic integration is recommended.

7. Reagents and Materials 7.1 Purity of Reagents--Reagent grade chemical shall be used in all tests. Unless otherwise indicated, it is intended that all reagents shall conform to the specification of the Committee on Analytical Reagents of the American Chemical Society, where such specifications are available. 5 Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination. 7.1.1 Normal octane is the recommended internal standard of choice. Other compounds may be found acceptable provided they are sufficiently resolved from any impurity and from the AMS peak. 7.2 Carrier Gas-- Chromatographic grade helium is recommended. 7.3 Compressed Air-- Chromatographic grade. 7.4 Hydrogen--High purity.

12. Calculations 12.1 Because some of the impurities identified in AMS are not available commercially, this test method is based on the use of theoretical response factors calculated with the use of effective carbon numbers (see Table 2). 6 12.2 For other impurities of known structure, the relative response factor can be calculated in a similar manner. For impurities of unknown structure, an average response factor of 0.94 is suitable if the impurity is believed to consist of only carbon and hydrogen, and 1.2 is suitable if the impurity is believed to contain oxygen. 12.3 Calculate the percent concentration of each impurity as follows:

8. Hazards 8.1 Consult current OSHA regulation, suppliers' Material Safety Data Sheets, and local regulations for all materials used in this test method.

9. Sampling and Handling

C, - (A,) (RRF,) (C2)) A2

(1)

where: C, = concentration of component i, weight percent, A, = peak area of component i, RRF , = relative response factor for component i, = peak are of n-octane, and A2 C2 = concentration of n-octane, weight percent. 12.4 Calculate the total concentration of all impurities as follows: Ct = x2C,

(2)

12.5 Calculate the purity of AMS as follows: A M S , w e i g h t percent = 100.00 - C t

(3)

13. Report

9.1 Sample the material in accordance with Practice D 3437.

10. Preparation of Apparatus

13.1 Report the individual impurities to the nearest 0.01%. 13.2 Report the purity of AMS to the nearest 0.01%.

14. Precision and Bias 7

10.1 Follow manufacturer's instructions for mounting and

14.1 Precision---The following criteria should be used to

s Reagent Chemicals, American Chemtcal Society Spectficatlons, American

~' Effective Carbon Numbers calculated using Table l, p. 336, of "Calculation of Flame Ionization Detector Relative Response Factors Using the Effective Carbon Number Concept" by Scanlon and Wdhs. Journal qfChromatographtc Scieme. Vol 23, August 1985, p. 333-339 7Supporting data are available from ASTM Headquarters. Request RR:D 16-1022

Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed by the American Chemical Society, see Analar Standards for Laboratory Chemwals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeta and National Formulary; U.S. Pharmacopeial Conventions, Inc. (USPC), Rockville, MD.

1031

~

D 6144

- , o ~,,o,o, o~,d - ~, - ?~. , ' v , . . - ~ d "

..~#=,'~3~d~--~/

~i, T" E'~

.......

"D 0 e-

Or)

, ~ : ' ~ r OT

.

.

.

.

.

.

.

g m

E o

Je0 O)

~- ~:,_ ~ T

,~,~l~r~

:)

. . . .

.l

ll.

.....

.o

c~ m

UL

~" 6

.

.

.

.

i

iii

L~IS

1032

~ D 6144 TABLE 2 Relative Response Factors (RRF) Based on Effective Carbon Numbers, (ECN) Compound n-octane Cumene 3-methyl-2-cyclopentene1-one n-propylbenzene tert-butylbenzene sec-butylbenzene 2-phenyl-2-butene (cls or trans) Acetophenone 2-phenyl-1 -butene AMS oxide AMS 2-phen-2-prepanol RO~

ECN 8.0 9.0 4.9

MW 114 120 96

Calculated RRF vs n-octane 1.000 0.936 1.375

9.0 10.0 10.0 9.9

120 134 134 132

3.936 0.940 0.940 0.936

7.0 9.9 8.0 8.9 8.5

120 132 134 118 136

1.203 0.936 1.175 0.930 1.123

- ECN(sT°) v ~ '

• (t

MW(,) lw

ECN (s'rm ECN(i) MW(sTD~ MW(,)

14.1.1 Repeatability-- Results in the same laboratory should not be considered suspect unless they differ by more than 0.03 %. 14.1.2 Reproducibility-- Results s u b m i t t e d by two laboratories should not be considered suspect unless they differ by more than 0.09 %. 14.2 Bias--Since there is no accepted reference material suitable for determining the bias in this test method for measuring these impurities, bias has not been determined. 15.

Keywords

•, (STD

where:

RRF(,)

from an interlaboratory study between six laboratories (only one laboratory was used for repeatability data). The data were obtained over one day using the same operators.

= relative response factor of compound i compared to the standard, = effective carbon number of the standard, = effective carbon number of compound i, = molecular weight of the standard, and molecular weight of compound i.

15.1 alpha m e t h y l s t y r e n e ; chromatography

AMS;

analysis

=

j u d g e the acceptability at the 95 % probability level of the results obtained by this test method. The criteria were derived The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be rewewed every five years and if not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for addihonal standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 100 Barr Harbor Drive, West Conshohocken, PA 19428.

1033

by

gas

(~T~ Designation: D 6159 - 97

Standard Test Method for Determination of Hydrocarbon Impurities in Ethylene by Gas Chromatography 1 This standard is issued under the fixed designation D 6159; the number immediately following the designation indicates the year of original adoption or, m the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsdon (e) indicates an editorial change since the last revision or reapproval.

1. Scope 1.1 This test method is used for the determination of methane, ethane, propane, propene, acetylene, iso-butane, propadiene, butane, trans-2-butene, butene-1, isobutene, cis-2butene, methyl acetylene and 1,3-butadiene in high-purity ethylene. The purity of the ethylene can be calculated by subtracting the total percentage of all impurities from 100.00 %. Since this test method does not determine all possible impurities such as CO, CO 2, H20, alcohols, nitrogen oxides, and carbonyl sulfide, as well as hydrocarbons higher than decane, additional tests may be necessary to fully characterize the ethylene sample. 1.2 Data are reported in this test method as ppmV (parts per million by volume). This test method was evaluated in an interlaboratory cooperative study in the concentration range of 4 to 340 ppmV (2 to 204 mg/kg). The participants in the interlaboratory cooperative study reported the data in non-SI units. Wherever possible, SI units are included. 1.3 This standard dose not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

2. Referenced Documents 2.1 ASTM Standards: D 2504 Test Method for Noncondensable Gases in C 2 and Lighter Hydrocarbon Products by Gas Chromatography 2 D 2505 Test Method for Ethylene, Other Hydrocarbons, and Carbon Dioxide in High-Purity Ethylene by Gas Chromatography 2 D 5234 Guide for Analysis of Ethylene Product 3 3. Summary of Test Method 3.1 A gaseous ethylene sample is analyzed as received. The gaseous sample is injected into a capillary gas chromatograph. A split-injector may or may not be used. The gas chromatograph is provided with a 6-port sampling valve and two wide

t This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricantsand is the d~rect responsibility of D02.D on Hydrocarbons for Chemical and Special Uses. 2 Annual Book of ASTM Standards, Vol 05.01. 3 Annual Book o f ASTM Standards, Vol 05.03.

1034

bore capillary columns connected in series. These columns are a dimethyl silicone column and a (porous layer open tubular column (PLOT) AI203/KC1 column. 4 A flame ionization detector is used for detection. The integrated detector signal (peak areas) are corrected for detector response. The hydrocarbon impurities are determined and the total impurities are used to determine the ethylene content.

4. Significance and Use 4.1 High-purity ethylene is required as a feedstock for some manufacturing processes and the presence of trace amounts of certain hydrocarbon impurities can have deleterious effects. This test method is suitable for setting specifications, for use as an internal quality control tool, and for use in development or research work. 4.2 This test method does not detect such impurities as H20, CO, CO 2, and alcohols that may be present in the sample. Hydrocarbons higher than n-decane cannot be analyzed by this test method, if present in the sample. Test Method D 2504 addresses the analysis of noncondensable gases and Test Method D 2505 addresses the analysis of CO 2. Guide D 5234 describes all potential impurities present in ethylene. These standards should be consulted when determining the total concentration of impurities in ethylene. 5. Apparatus 5.1 Gas Chromatograph (GC), a gas chromatographic instrument provided with a temperature programmable column oven and a flame ionization detector (FID). Regulate the carder gas by pressure control. 5.2 Detector--Use a flame ionization detector (FID) having a sensitivity of approximately 2.0 ppmV (I .2 mg/kg) or less for the compounds listed in 1.1. An FID was exclusively used in the interlaboratory cooperative study. 5.3 Column Temperature Programmer--The chromatograph shall be capable of linear programmed temperature operation over a range sufficient for separation of the components of interest. Section 8 lists the recommended operating conditions. The programming rate shall be sufficiently reproducible to obtain retention repeatability of 0.05 min (3 s) throughout the scope of this analysis. 5.4 Columns--Couple the two columns in series with either 4 This column is supplied by major column manufacturers.

@

D 6159

a glass press tight connector or a mini-connector equipped with graphite ferrules. 5.4.1 Column 1, 50 m, 0.53 mm inside diameter (ID) KCl deactivated Al203 PLOT column. 4 Relative retention is dependent on the deactivation method of the column. Other deactivated A1203 plot columns using sulfates as the deactivating agent were also used in the interlaboratory comparison. 5.4.2 Column 2, 30 m, 0.53 mm ID, 51am film thickness methyl silicone. This column improves the separation of methyl acetylene, iso-pentane, and n-pentane. 5.5 Sample Inlet System--Two injection modes were used for the interlaboratory cooperative study. 5.5. l A gas sampling valve placed in an unheated zone of the gas chromatograph injecting the sample directly into the column. 5.5.2 A gas sampling valve placed in an unheated zone of the gas chromatograph in conjunction with a splitter injector heated with a variable temperature control. 5.6 Gas Sampling Valve and Injection System--Use a 6-port valve provided with I//16 in. fittings as the sample injection system. A typical valve arrangement is shown in Fig. 1 and Fig. 2. Use a 10-60~tL loop as shown in Fig. 1. Use good valve maintenance techniques to avoid such problems as dead volumes, cold spots, long connections, and non-uniform heated zones. The preferred carrier gas arrangement for sample introduction is pressure regulation. Use a 6-port valve in conjunction with a splitter injector. A typical arrangement is shown in Fig. 3 and Fig. 4. Use split ratios of 50:1 to 100:1 at temperatures of 150°C to 200°C. Loop sizes of 200-5001aL were used in the interlaboratory study. When using a splitter it is important to check linearity of the splitter. Inject the standard blend at 50:1, 75:1, and 100:1 split ratios. Check the response factors as determined in 9.1, and the factors shall not vary more than 3 %. 5.7 Data Acquisition System--Use any integrator or computerized data acquisition system for peak area integration, as well as for recording the chromatographic trace.

SAMPLE IN

LOOP 60pL C

standard containing levels of 2 to 204 mg/kg (4 to 340 ppmV) of each of the trace components listed in Table 1 to calibrate the detector's response. The standard gas mixture shall be prepared gravimetrically from known raw materials, and cross

COL1

SAMPLEOUT

H2~AIR

" c~ COL1

COL2

FIG. 2 Valve On - Injection

SAMPLEIN

~

6

Loop C 200pL

T

SPLITVENT ,

--g

CARRIER He

r

l

R~I H2

IR

N2__,l COL1

COL2

FIG. 3 Valve Off - Sample Loading

SAMPLEIN i

Loop ~ S A M P L E

CA.R,E.

t-TL

OUT

s,u,v,

"%A,. COL1

COL2

FIG. 4 Valve On - Injection

contaminants shall be taken into account. The mixtures should be certified analytically such that the gravimetric and analytically derived values agree to an acceptable tolerance; that is _+ 1 or _+ 2 %. The concentration of the minor components in the calibration standard shall be within 20 to 50 % above the concentration of the process stream or samples. 6.2 Compressed Helium, gas having purity of 99.999 %, or better, with a total hydrocarbon level of < lppmV.

SAMPLE IN

LOOP 60pL

=1~

N2---~ I

CARRIER He

6. R e a g e n t M a t e r i a l s

6.1 Standard Mixture--Use a gravimetrically blended gas

r~RD H2 TAIR

SAMPLEOUT

N2----~ I ~__j COL2

NOTE l--Compressed helium is a gas under high pressure. 6.3 Compressed Hydrogen, gas used as fuel in the FID detector (less than 1.0 ppmV hydrocarbon impurities).

CARRIER He

NOTE 2--Hydrogen is an extremely flammable gas under high pressure. 6.4 Compressed Air--Air having less than 1.0 ppmV of

FIG. 1 Valve Off - Sample Loading 1035

~

D 6159

TABLE 1 Typical Compounds and Retention Times for Common Hydrocarbon Im ~urities in Ethylene A Components Methane Ethane Ethene Propane Propene Ethyne Isobutane Propadiene

Butane t-2-Butene Butene-1 Isobutylene c-2-Butene Propyne

1,3-Butadiene

Makeup = N 2 at 20mL/min Range = suitable to obtain measurable counts for the impurities Injection System using a Valve Directly Sample valve loop volume = 10-601al Sample valve temperature = 35 to 45°C 8.2 When the G.C. has achieved a ready status, proceed with analysis.

Retention Time, rain 7 O2 8.12 9.00 12.41 16.93 19.52 19.76 20.48 20.78 24.99 25.23 25.90 26.71 29.14 30.37

9. Calibration

"Conditions as specified in Section 8.

hydrocarbon impurities for the operation of the FID is recommended. NOTE 3---Compressed air is a gas under high pressure and supports combustion.

9.1 Proceed to inject the standard mixture. Connect the gaseous sample to the sample port and flush the sample loop for a period of 30 s. Close the standard sample cylinder outlet and when the pressure drops to atmospheric pressure and no sample elutes, inject the standard sample and proceed with the analysis. At least three standard determinations should be made to obtain a relative standard deviation of the measurements. 9.2 D e t e r m i n a t i o n o f Calibration F a c t o r s - - F o r each impurity present in the standard, calculate the calibration factor as follows: c f = Ci/Ai

6.5 Compressed Nitrogen--Nitrogen having less than 1.0 ppmV of hydrocarbon impurities is used as make up gas in order to increase the response of the FID.

( 1)

where:

c f = the calibration factor, Ci = the concentration of the impurity i in the standard

NOTE 4---Compressed nitrogen is a gas under high pressure.

7.1 Gas samples are collected in 1000 mL stainless steel cylinders equipped with a rupture disk capable of sustaining 5500 to 6900 kPa (800 to 1000 psi) in order to protect against dangerous pressure build up. It is important to thoroughly flush the cylinder with the sample prior to sealing, thus excluding air and other contaminants that may be present in the cylinder.

(usually expressed as ppmV), and = the area counts obtained for that impurity as integrated by the data acquisition system. 9.2.1 It is important that the system linearity is checked by injecting standard gas samples of varying impurity concentration over a range covering the impurity concentration range in the samples analyzed. Verify that the system responds linearly and that the response is of the type y = mx + b with b = 0. Use a linear calibration forced through the origin.

8. Preparation of Apparatus

10. Procedure

Ai

7. Sampling

8.1 Instrument Conditions--Adjust the instrumental param-

eters to the following conditions: Column Temperature Equilibration time: 2.0 min Initial: 35°C Final: 190°C 5 Rate: 4°C/min Initial time: 2.0 min Final time: 15 rain. Carrier Gas Helium at 6 to 8 mL/min Injection System with Splitter Sample valve loop volume = 200-500pl Sample valve temperature = 35 ° to 45°C Splitter temperature = 150 ° to 200°C Split ratio = 50:1 to 100:1 Flame Ionization Detector, 300°C Air = 300mL/min 6 H2= 30mL/min

10.1 The sample shall be injected under the same temperature and pressure conditions as the standard mixture. 10.2 Connect the gas sample to the G.C. sample port. Flush the loop for a period of 30 s. Close the sample cylinder shut-off valve and inject the sample the moment the loop reaches atmospheric pressure. Integrate the areas of the impurities. Identify the impurities by comparing their retention time to that obtained with the standard mixture. A typical sample chromatogram is shown in Fig. 5. 11. Calculations 11.1 Calculate the concentration of each impurity to the nearest ppmV as follows: Ci = (Cfi)(Ai)

PLOT AI203 columns should not be heated above 200°C since above this temperaturethe columnactivityis changed. 6 Followthe valuessuggestedby instrumentmanufacturer.

(2)

where Ci = concentration of the impurity in the sample in ppmV, Cfi = calibration factor previously calculated in Eq. 1 (units are usually ppmV/counts), and Ai = integrated area of the impurity from the data acquisition system. 11.2 Determine the total amount of hydrocarbon impurities by summing the concentrations of the individual impurities.

1036

(1~'~ O 6159 1 2 3 4 5 6 7 8 9 10 11 12 13 14

0.0150-

COMPONENT

mg/kg

METHANE ETHANE PROPANE PROPYLENE ACETYLENE ISOBUTANE PROPADIENE N-BUTANE t-2-BUTENE BUTENE-I ISOBUTYLENE c-2-BUTENE M E T H Y L ACETYLENE 1,3, BUTADIENE

66 588 16 0 19 0 15.0 30.0 16 0 39 0 16 0 32 0 50 0 15 0 28 0 15 0

001(30-

6

0.0050-

I

12

13 ~

0.0000-

~!o 2!o

ld.O 111.01;]0 131014[.0ld.O 1dO FIG. 5

Typical Chromatogram

Calculate the concentration of the ethylene by subtracting the total impurities concentration from 100.00 %. Since this test method cannot measure such impurities as CO, CO 2, 02, N 2, H20 and alcohols, it will be necessary to analyze the ethylene for these impurities as described in Test Methods D 2504 and D 2505. The sum total of all impurities analyzed should be used in reporting the ethylene concentration. 12. Precision and Bias 7

12.1 Precision: 7 Supporting data is available from ASTM Headquarters. D02-1412.

Request RR.

12.1.1 An interlaboratory cooperative study was adopted with 7 laboratories participating. Fourteen hydrocarbon impurities in ethylene were measured; the results obtained are shown in Table 2. 12.1.2 Repeatability--The difference between successive results obtained by the same operator with the same apparatus under constant operating conditions on identical test materials would, in the long run, and in the normal and correct operation of the test method exceed the values only one case in twenty as shown in Table 2, where r is the repeatability and X is the concentration (ppmV) of the component. 12.1.3 Reproducibility--The difference between two single and independent results obtained by different operators

TABLE 2 Repeatability and Reproducibility Component Methane Ethane Propane Propene Ethyne isobutane Propadiene Butane t-2-Butene Butene-1 isobutylene C-2-Butene Propyne 1,3 Butadiene

Range, p p m V 5.57 35.1 8.07 4.67 4 14 7.74 4.53 4.97 7.20 6.18 4 13 6.16 6.57 5.80

- 62.3 - 338 - 59.7 - 49.2 - 34.4 - 48 4 - 67.6 - 56.1 - 55.9 - 56.9 - 55.6 - 56 6 - 62.3 - 49.1

Repeatability, (r)

Reproducibility (R)

0 . 0 2 2 7 7 X " 0.6 0.03811 X 0 0 3 2 7 3 (X + 21.23) 0 0 4 7 8 0 X " 1.15 0.1189 X 0.8 0 . 0 4 3 7 0 X ^ 1.07 0.05091 (X + 0.7831) 0.1156 X ^ 0.85 0 . 0 6 3 9 6 0 X " 0.95 0 . 0 3 9 9 2 (X + 17.14) 0.1229 X " 0.85 0 . 0 8 3 5 0 X " 0.93 0 . 0 7 5 1 8 ^ 0.9 0 . 0 5 2 0 5 X ^ 1.1

1.408 X " 0.6 0.3165 X 0.2277 (X + 4.558) 0 . 4 8 4 9 X " 1.15 5.471 X 0.8 0 . 6 7 2 8 X ^ 1.07 0 7 2 5 6 (X + 0 . 7 8 3 1 ) 0.4399 X " 0.85 0.2196 X 0.95 0.1600 (X + 7.028) 0 . 3 1 7 4 X " 0.85 0 . 3 0 1 7 X " 0.93 1.136 X " 0.90 0.4613 X ^ 1 1

1037

~'~ D 6159 working in different laboratories on identical material would, in the long run, exceed the values in only one case in twenty as shown in Table 2, where R is the reproducibility and X is the mean concentration (ppmV) of the component. 12.2 Bias--There is, at this time, no accepted reference

material suitable for measuring bias for this test method. 13. Keywords 13.1 ethylene; gas chromatography; hydrocarbon impurities

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validtty of any such patent rights, and the risk of infnngement of such nghts, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and ff not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will recetve careful consideration at a meeting of the responsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 100 Barr Harbor Drive, West Conshohocken, PA 19428.

1038

(~~ll~ Designation: D 6160 - 97 Standard Test Method for Determination of Polychlorinated Biphenyls (PCBs) in Waste Materials by Gas Chromatography 1 This standard is issued under the fixed designation D 6160; the number immediately following the designation indtcates the year of original adoption or, in the case of revision, the year of last revision. A number an parentheses indicates the year of last reapproval. A superscript epsilon (e) indicates an editorial change since the last revision or reapproval.

1. Scope 1.1 This test method 2 is a two-tiered analytical approach to PCB screening and quantitation of liquid and solid wastes, such as oils, sludges, aqueous solutions, and other waste matrices. 1.2 Tier I is designed to screen samples rapidly for the presence of PCBs. 1.3 Tier II is used to determine the concentration of PCBs, typically in the range of 2 to 50 mg/kg. PCB concentrations greater than 50 mg/kg are determined through analysis of sample dilutions. 1.4 This is a pattern recognition approach, which does not take into account individual congeners that might occur, such as in reaction by-products. This test method describes the use ofAroclors 3 1016, 1221, 1232, 1242, 1248, 1254, 1260, 1262, and 1268, as reference standards, but others could also be included. Aroclors 1016 and 1242 have similar capillary GC patterns. Interferences or weathering are especially problematic with Aroclors 1016, 1232, and 1242 and may make distinction between the three difficult.

responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulator limitations prior to use.

NOTE 1 - - A r o c l o r is a r e g i s t e r e d t r a d e m a r k o f M o n s a n t o .

1.5 This test method provides sample clean up and instrumental conditions necessary for the determination of Aroclors. Gas chromatography (GC) using capillary column separation technique and electron capture detector (ECD) are described. Other detectors, such as atomic emission detector (AED) and mass spectrometry (MS), may be used if sufficient performance (for example, sensitivity) is demonstrated. 1.6 Quantitative results are reported on the dry weights of waste samples. 1.7 Quantification limits will vary depending on the type of waste stream being analyzed. 1.8 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the This test method Is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibdity of Subcommittee D02.04on Hydrocarbons Analysis Current edition approved July 10, 1997. Published September 1997. z Thts test method is based largely on EPA 8080 (and the proposed modification for the use of capdlary columns, EPA 8081) and EPA Report 600/4-81-045 by Bellar, T. and J. Llchtenberg, reported in 1981. The report is titled," The Determination of Polychlorinated Btphenyls in Transformer Fluid and Waste Oils" and provides significant support to the protocol below. Aroclor Standards may be purchased as 1000 ug/mL in isooctane.

1039

2. Referenced Documents 2.1 ASTM Standards: D 4059 Test Method for Analysis of Polychlorinated Biphenyls in Insulating Liquids by Gas Chromatography 4 E 203 Test Method for Water Using Volumetric Karl Fischer Titration 5 E 288 Specification for Laboratory Glass Volumetric Flasks 6 E 969 Specification for Glass Volumetric (Transfer) Pipet 6 2.2 U.S. EPA Standards: Method 608 Organochlorine Pesticides and PCBs Environmental Monitoring and Support Laboratory, Cincinnati, Ohio. EPA Report 600/4/82-057. 7 Method 680 Determination of Pesticides and PCBs in Water and Soil/Sediment by Gas Chromatography/Mass Spectrometry 8 Method 8080 Organochlorine Pesticides and PCBs 9 Method 8081 Organochlorine Pesticides and PCBs As Aroclors By Gas Chromatography: Capillary Column Technique 9 Method 3620 Florisil Column Clean-Up 9 Method 3630 Silica Gel Clean-Up 9 Method 3660 Sulfur Clean-Up 9 3. Terminology 3.1 Definitions of Terms Specific to This Standard: 3.1.1 Aroclors, n---commercial mixtures of polychlorinated biphenyl congeners marketed and trademarked by Monsanto prior to 1977.

4 ASTM Annual Book of Standards, Vol. 10.03. ASTM Annual Book of Standards, Vol. 15.05. 6 ASTM Annual Book of Standards, Vol. 14.02. 7 EPA Report 600/4/82--057. "Organochlorine Pesticides and PCBs" Environmental Momtoring and Support Laboratory, Cincinnati, OH. "Determination of Pesticides and PCBs in Water and Soil/Sediment by Gas Chromatography/Mass Spectrometry", Ann Alford-Stevens et al, Physical and Chemical Methods Branch, Environmental Monitoring and Support Laboratory Office of Research and Development, USEPA, Cincinnati, OH 45268. 6 9 U.S. EPA, "Test Methods for Evaluating Solid Waste, Physical~Chemical Methods," SW-846.

(~ D 6160 3.1.1.1 Discussion--Specific Aroclors are usually designated by a four-digit number, with the first two digits usually designating the number of carbon atoms and the last two digits providing the chlorine content (for example, Aroclor 1260 is 60 % (wt) chlorine). 3.1.2 congeners, n - - c o m p o u n d s related by structural similarities. 3.1.2.1 Discussion--All polychlorinated biphenyls (PCBs) share the s a m e CI2 structure and vary only by the number and position of the chlorine atoms attached to the aromatic rings. 3.1.3 continuing calibration standard (CCS)--a known blend or one or more Aroclors at a fixed concentration which is injected into the gas chromatograph to demonstrate the validity of the calibration. 3.1.4 dry weight, n---concentration of PCBs after factoring out the water content. 3.1.4.1 Discussion--This correction assumes that all PCBs originated from nonaqueous sources and any water present has been added subsequently, diluting the original concentration. This correction can be described using the formula: Aroclor (mg/Kg) (wet) Aroclor (mg/Kg) (dry) = (100 - % water)/100

the midpoint calibration standard of Aroclar 1016 and 1260 to the five-point calibration curve. (See Appendix X1 for an example chromatogram and calibration table.)

5. Significance and Use 5.1 This test method provides sufficient PCB data for many regulatory requirements. While the most common regulatory level is 50 ppm (dry weight corrected), lower limits are used in some locations. Since sensitivities will vary for different types of samples, one shall demonstrate a sufficient method detection limit for the matrix of interest. 5.2 This test method differs from Test Method D 4059 in that it provides for more sample clean-up options, utilizes a capillary column for better pattern recognition and interference discrimination, and includes both a qualitative screening and a quantitative results option. 6. Interferences 6.1 The electron capture detector (ECD) has selective sensitivity to alkyl halides, conjugated carbonyls, nitrogen compounds, organometallics, and sulfur. Therefore, the chromatogram obtained for each sample shall be carefully compared to chromatograms of standards to allow proper interpretation. 6.2 Solvents, reagents, glassware, and other sample processing hardware may yield artifacts or interferences, or both, to standard analysis. All these materials must be demonstrated to be free from interferences under the conditions of analysis by analyzing method blanks. 6.3 Interferences from phthalate esters may pose a major problem in Aroclor determinations when using ECD. Phthalates generally appear in the chromatogram as broad late eluting peaks. Since phthalates are commonly used as plasticizers and are easily extracted from plastic, all contact of samples and extracts with plastic should be avoided. 6.4 While general clean-up techniques are provided as part of this test method, some samples may require additional clean-up beyond the scope of this test method before proper instrumental analysis may be performed.

(1)

3.1.5 instrument performance standard (IPS), n--a known low level of an Aroclor in a clean solvent used as a comparator to determine which qualitative (screening) results are of sufficient magnitude to require quantitative analyses. 3.1.6 waste material, n--any matter, within the scope of this test method, which is in the process of being recycled or disposed.

4. Summary of Test Method 4.1 The sample is extracted with solvent and the extract is treated to remove interfering substances, if needed. The sample extract is injected into a gas chromatograph. The components are separated as they pass through the capillary column and polychlorinated biphenyl compounds, if present, are detected by an electron capture detector (ECD). NOTE 2--Portions of this test method are similar to EPA Methods 608, 680, 8080, and 8081. 4.2 For screening (Tier I), instrument performance is monitored by a 2-uL injection of a standard containing Aroclors 1016 and 1260. For low level work (1 ppm) the instrument is checked with a standard concentration of 0.01 ug/mL (each) and for higher level work (10 ppm), the instrument is checked with a 0.1 ug/mL standard. 4.3 Identification involves a pattern comparison of the chromatograms of an unknown sample with that of a standard obtained under identical instrumental conditions. 4.4 When quantification is required (Tier II), an external standards method (ESTD) is used. The quantitation technique typically requires a comparison of five peaks (minimum of three) between the chromatograms of an unknown sample and that of standard Aroclor obtained under identical conditions. Quantitation of either Aroclors 1016 or 1260 is performed using a five-point calibration of a mixed Aroclor standard containing Aroclors 1016 and 1260. All remaining Aroclors are quantitated from single point calibrations. Calibration is verified daily by comparison of results obtained for analysis of

7. Apparatus 7.1 Gas Chromatograph, a temperature programmable gas chromatograph suitable for splitless injections; equipped with an electron capture detector (ECD). 7.2 Data System, a data system capable of measuring peak areas. 7.3 Regulator (Make-up Gas)--N 2 or Ar:Methane (95:5); two stage regulator rated at 20 MPa (3000 psi) inlet and 35 to 860 kPa (5 to 125 psi) outlet. 7.4 Regulator (Carrier Gas)--tt 2, two-stage regulator rated at 20 MPa (3000 psi) inlet and 35 to 860 kPa (5 to 125 psi) outlet. 7.5 Gas Purifiers, to remove moisture and particulates. Depending on the levels and types of interferences encountered, these might involve molecular sieves (moisture), activated carbon (organics), or other commercially-available media. 7.6 Flow Meter, to measure gas flow. Typical range is 0.5 to 50 mL/min. + 0.1 mL/min.

1040

~T~ D 6160 7.7 Column, crosslinked 5 % phenyl methyl silicone, 30 m by 0.32 mm id by 0.25 um film thickness. 7.7.1 It is possible that other columns will provide sufficient separating power, but this shall be demonstrated before use. 7.8 Analytical Balance, capable of weighing to 0.0001 g. 7.9 Volumetric Flasks, 10, 50, 100, 200 mL, (see Specification E 288) Class A with ground-glass stoppers.

7.10 Vortex Mixer: 7.11 Vials, glass. 20 mL and 40 mL capacity with TFEfluorocarbon-lined caps. 7.12 Septum Inserts--Inserts shall be treated with a silynization reagent before use or after cleaning. (See Annex A2 for possible procedure.) They may be purchased already treated. 7.13 Volumetric Pipette, 1, 5, 10 mL (see Specification E 969), Class A. 7.14 Syringe, 500 uL, mechanical guide.

8. Reagents and Materials 8.1 Purity of Reagents--Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society where such specifications are available. I° Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination. 8.2 Acetone--See Note 3. NOTE 3--Warning: Extremely flammable.Vapors may cause flash fire. 8.3 Activated Magnesium Silicate (Florisil), Pesticide residue (PR) grade (60/100 mesh); store in glass containers with ground glass stoppers or foil lined screw caps. 8.3.1 Just before use, activate each batch at least 4 h at 130°C in a glass container loosely covered with aluminum foil. Alternatively, store the magnesium silicate in an oven at 130°C. Cool the magnesium silicate in a desiccator for 30 min before use. 8.4 Hexane--See Note 4. NOTE 4---Warning: Extremely flammable. Harmful if inhaled. May produce nerve cell damage. Vapors may cause flash fire. 8.5 Isooctane--See Note 5. NOTE 5--Warning: Extremely flammable. Harmful if inhaled. Vapors may cause flash fire. 8.6 Methanol---See Note 6. NOTE &---Warning: Flammable. Vapor harmful. May be fatal or cause blindness if swallowed or inhaled. Cannot be made nonpoisonous. 8.7 Silynization Reagent (for example, 5 % dimethyldichlorosilane in toluene). See Annex A2 for instructions.

"~Reagent Chemtcals, American Chemical Society Specifications, American Chemical Society, Washington, DC. for suggestions on the testing of reagents not listed by the Amerian Chemical Society, See Analar Standards for Laboratory Chemicals, BDH Ltd., Peele. Dorset, U.K., and the Umted States Pharmacopeia and National Formulary, U.S Pharmaceutical Convention, Inc. (USPC), Rockville, MD.

1041

8.8 Sodium Sulfate, granular, anhydrous (maintained at 130°C for at least 24 h prior to use). Cool the sodium sulfate in a desiccator for 30 min before use. 8.9 Sulfuric Acid (concentrated): 8.10 Acetone/Hexane, 10 % acetone/90 % hexane (v/v). 8.11 Gases, Hydrogen (zero grade; 99.995 % purity) and nitrogen (zero grade; 99.998 % purity) or argon/methane (95:5; ECD grade). 8.11.1 Care shall be given to ensure purity of the carrier gas. For example, an in-line filter may be required. 8.12 Aroclor Standards 3, Aroclor 1016, 1221, 1232, 1242, 1254, 1260, 1262, 1268. 8.13 Decachlorobiphenyl (DCB) (surrogate) Optional:

8.13.1 Surrogate Stock Standard (15 ug/mL) Preparation-Accurately dilute 1.5 mL of 1000 ug/mL DCB concentrate in 100 mL volumetric flask and fill to the mark with methanol, yielding a 15 ug/mL solution. 8.13.2 Surrogate Working Standard (1.5 ug/mL) Preparation--Accurately dilute 10 mL of the 15 ug/mL DCB stock standard in a 100 mL volumetric flask and fill to the mark with methanol, yielding a 1.5 ug/mL working DCB standard. NOTE 7 - - S a m p l e preparations will normally use 0.1 m L of this solution. The resulting concentration in the sample extract is 0.005 ug/mL before any further dilutions. The following calculations show this. 1.5 u g / m L × 0.1 m L = 0.15 ug 0.15 ug (3.0 m L sample + 27 mL) = 0.005 u g / m L

(2)

8.14 Calibration Standards: 8.14.1 Intermediate Stock Standard (50 ug/mL): If high level standards (for example, commercially available standards at 2000 to 5000 ug/mL) have been purchased, prepare solutions of 50 ug/mL concentration. 8.14.1.1 The surrogate calibration standard may be added (optional) to the Aroclor 1016/1260 intermediate stock standard at a concentration of 2.5 ug/mL. For preparation of the standard, add 500 uL of 50 ug/mL surrogate to a I0 mL volumetric flask containing 3.0 mL of isooctane. Add the Aroclor 1016/1260 standard (5.0 mL at 100 ug/mL) to the flask. Dilute to 10 mL volume with isooctane and mix well. 8.14.1.2 To prepare the continuing calibration standard (CCS), dilute 200 uL of the intermediate stock standard to 100 mL. Volume add i n t o the 100 mL flask 200 uL

Ar-1016/1260concentration ug/mL 0.10

Surrogateconcentration ug/mL 0.005

8.14.2 Instrument Performance Standard (1PS) (Tier I-Screening)--An isooctane solution of Aroclors 1016 and 1260 is prepared at a concentration of 0.01 ug/mL (each) or 0.1 ug/mL (each) (depending on whether the minimum level of interest is 2 ug/mL or 20 ug/mL) from the appropriate stock standard. 8.14.2.1 If the surrogate (decachlorobiphenyl, (DCB)) is used, it shall be added to the IPS to result in a concentration of 0.005 ug/mL. 8.14.2.2 To prepare the IPS along with DCB, add 10 mL of Aroclor 1016/1260 at 0.1 ug/mL and 0.033 mL of DCB at 15 ug/mL into 100 mL volumetric flask. Dilute to 100 mL volume with isooctane. Mix well. This yields 0.01 ug/mL IPS and

D 6160 0.005 ug/mL of DCB. 8.14.2.3 The following additional standards shall be run once (at 0.1 ug/mL) to demonstrate the Aroclor patterns and be mixed if preferred. Aroclor 1268 1262 1254

Mtx with the following: 1221 or 1232 or 1242 or 1248 or 1254 1221 or 1232 or 1242 or 1248 1221

8.14.3 Individual Working Standards (Tier 2-Quantitation)--Working standards are typically prepared in isooctane at concentrations of 0.02 ug/mL, 0.05 ug/mL, 0.1 u/mL, 0.3 ug/mL and 0.5 ug/mL for Aroclors 1016 and 1260. All other Aroclors are prepared at the mid level concentration (0.1 ug/mL) for the single point calibration. An alternative calibration range may be used as long as the criteria for linearity of the calibration range is documented. 8.14.3.1 Aroclors 1016 and 1260 shall be a mixed standard. The following additional standards shall be run once (at 0.1 ug/mL) to demonstrate the Aroclor patterns and may be mixed, if preferred. Aroclor

May be mixed wfth.

1268 1262 1254

1221 or 1232 or 1242 or 1248 or 1254 1221 or 1232 or 1242 or 1248 1221

8.15 Quality Control Standards: 8.15.1 Calibration Check Standard (CCS) (Tier 2-Quantitation)--This standard contains 0.1 ug/mL (those who are interested in the 20 mg/Kg level with no compositing, use 0.2 ug/mL each) each of Aroclors 1016 and 1260 in hexane. 8.15.1.1 The surrogate concentration, if used, is 0.005 ug/mL. 8.15.1.2 Example--To prepare the CCS along with DCB, add 20 mL of Aroclors 1016/1260 to 0.5 ug/mL and 0.05 mL of DCB at 10 ug/mL into 100 mL volumetric flask. Dilute to 100 mL volume with isooctane. Mix well. This yields a 0.1 ug/mL of CSS and 0.005 ug/mL of DCB.

8.15.2 Matrix Spiking Standard (Tier 2-Quantitation)--The matrix spiking standard is to contain Aroclor 1268 at a concentration of 50 ug/mL in methanol. Laboratories working at lower calibration ranges will need to dilute this (for example, to 25 ug/mL). 8.16 Mercury, ACS Reagent--See Note 8. NOTE 8--Warning: Handle mercury with care. Keep a minimum on site.

a closed container with minimal headspace. It is accepted practice to use borosilicate glass containers with TFEfluorocarbon-lined lids.

10. Preparation of Apparatus 10.1 General Gas Chromatographic Conditions--The first temperature profile (12 min run time) is used for Tier 1 screening method for the presence of Aroclor. The longer second temperature profile (17 min run time) is used for Tier II to quantitate the Aroclors present, but may also be used for Tier I, if desired. 10.1.1 Rapid Screen Capilary Column Oven Temperature Profile (Tier I, 12 min run time): Intttal value Initial time Program rate Final value Final time Carrier gas Head pressure

130°C 2 mm 20°C/mm 270°C 3 min hydrogen depend on DCB RT (approxtmately 105 KPa (15 psi)) column flow' 3.1-3.2 mL/min nttrogen or argon: methane approximately 65 mL/mm.

Make-up gas Make-up gas rate Splitless mode Purge off Purge on Purge vent Spht vent Sample tnlectton Injector inlet system Detector

0 min 1.0 min 2 5 mL/min 50 mL/mm 2.0 uL 250°C 315°C

10.1.2 Quantitation Capillary Column Oven Temperature Profile (Tier I1, 17 min run time; may also be used for Tier I analysis: Intttal value Initial hme

125°C 3 mm

Level I Program rate Final value Final time

12°C/ram 270°C 2 mm

Carrier gas Head pressure Column flow Make-up gas Make-up gas rate

hydrogen Depend on DCB RT (approxtmately, 105 KPa (15 psi)) 3.1 mL/min (approximately at 270°C) nttrogen approxtmately 65 mL/min

Sphtless mode Purge off Purge on Purge rate Sample mlechon

0 min 1 0 mm 50 mL/mm 2 0 uL

Inlector mlet system Detector

250°C 315°C

8.17 Silica Gel, 100 to 200 mesh.

9. Sampling 9.1 PCBs are hydrophobic compounds. Therefore, when sampling, all organic phases, including bottom sludge beneath aqueous phases, shall be sampled. Given the possible presence of alcohols and glycols, it is typically not acceptable to sample the organic phase only. 9.2 Headspace above stored standards and samples or extracts should be minimized such that the volume is less than 50 %. 9.3 Three mL of sample are required for each determination. No special sample preservation is required other than storage in 1042

11. Calibration and Standardization 11.1 Calibration: 11.1.1 Tier 1-Screening Method--Aroclors are multi-peak chemical mixtures that have very unique identification patterns. All Aroclors shall be run individually or in mixtures at 0.1 ug/mL on each channel performing screening to produce reference patterns. It is important to note that some of these patterns have the same constituents and that some Aroclors are quantitated using the same peaks (such as Aroclors 1016 and 1232 or 1242). When screening for Aroclors, a visual

o 618o

. • / •n---]Xf

determination is made by the following key items:

(X, -

11.1.I.1 Aroclor pattern--(a) same singlets, doublets, and triplets present in the reference chromatograms, and (b) same relative peak heights between peaks in the sample chromatogram and the reference chromatogram. 11.1.1.2 Retention time shifts should be very consistent between the standard and the sample peaks. 11.1.1.3 All samples in which an Aroclor is detected (using Tier I) require a judgment concerning the amount. The recognized Aroclor pattern shall be compared to the IPS (0.01 ug/mL or 0.1 ug/mL). If the overall level of the suspected Aroclor pattern is equal to or greater than overall level of the IPS pattern, then Tier II analysis may be used to quantitate the sample. If multiple Aroclors are suspected, a Tier II analysis may be run to help resolve the mixture. 11.1.1.4 Recovery control limits for the surrogate are 40 to 150 % recovered. If the recovery is outside of these limits, see Annex A 1. 11.1.2 Tier I Calibration C h e c k - - A n instrument performance standard (IPS) at 0.01 ug/mL of Aroclor 1016 and 1260 is used to check the instrument sensitivity once a day or ever3.' 20 samples, whichever is more frequent (typically laboratories using ten samples compositing shall use the 0.01 ug/mL standard to achieve a detection limit of 5 ug/mL of Aroclor in any individual sample). Sample results will be compared qualitatively with the daily IPS. (See the Calculation section 13). 11.1.2.1 Tabulate the sum of the areas or the data system calculated amount of the five major peaks for each of the Aroclors 1016 ad 1260 in the instrument performance standard. The response shall be within 50 % of the initial response. Initial response shall be established by averaging the response of a minimum of five injections of the instrument performance standard (IPS). If the limit is exceeded, new limits may need to be established. 11.1.2.2 Likewise, the expected response for the surrogate, if used, is established by averaging the areas of DCB in the five initial IPS analyses. 11.1.2.3 The surrogate also may be used for retention time control. It is recommended that column flow be adjusted so DCB elutes between 10.5 to 11.5 min using the 12 min GC program. (This will typically require a column head pressure of 105 to 112 kPa.) (Alternatively, the retention time should be 15 to 16.5 min using the 17 min program.) l 1.1.3 Tier 2-Quantitative Method--The GC data system must be calibrated for both Aroclors 1016 and 1260, using five peaks for each Aroclor. [For example, when using an integrator, divide the standard amount by the number of peaks being used. Using five peaks on a 0.5 ug/mL standard would assign 0.1 ug/mL to each peak. This will allow for a calibration table to be made, yielding response factors for each peak at the five levels of calibration. Set up a calibration table in the method file of the integrator or data system that is to be used. Calculate an average response factor for each of five peaks for both Aroclors. Calculate the standard deviation of the average response factor for each peak of the Aroclor using the following calculation. 1043

S= ~ , = ~

(3)

where: S = standard deviation, x, = each observed value, X = the arithmetic mean of observed values, and n = total number of calibration points. 11.1.3.1 Calculate the percent relative standard deviations (% RSDs) for the response factors of the calibrated peaks for each Aroclor from the formula below. The acceptance criteria for the % RSD for each Aroclor is --< 20 %. If the average % RSD is greater than 20 % for either Aroclor, then linearity over the desired calibration range for that instrument has not been demonstrated. NOTE 9--The % RSD is 100 % multiphed by the result of Eq. 3 (s) divided by the arithmetic mean (X). 11.1.3.2 When samples are to be analyzed, instrument control is verified by analyzing the CCS and the percent difference (% D) is calculated. The acceptance criteria is within +30 % for each AROCLOR in the CCS (1016 and 1260). 11.1.3.3 If either Aroclor 1016 or 1260 is out of control for the daily CCS, corrective action shall be taken and a CCS reanalyzed. If corrective action does not correct the problem, then a new five point calibration curve shall be created. Percent difference (% D) Am h -

%D=

Amt c

Amh

× 100%

(4)

where: Amh = amount in standard, and Amt c = calculated amount from current CCS. 11.1.3.4 Calibration for Aroclors other than Aroclor 1016 and Aroclor 1260 will be performed by analyzing standards at the concentration representing the midpoint of the calibration range selected. For example, if calibration is desired over the range of 0.02 ug/mL to 0.5 ug/mL, then the 0.1 ug/mL standards shall be used for calibration. Therefore, a five point calibration shall be performed for Aroclors 1016 and 1260 and a one-point calibration shall be performed for all remaining Aroclors. 11.1.3.5 After the linearity of the system has been demonstrated, and each of the remaining Aroclors has been analyzed using middle level concentration, recalibration will be required only when the calibration check standard criteria is met. Old calibration curves may not be used again, other than to review data generated using those calibration curves. 11.2 Standardization: 11.2.1 Surrogate Recovery--Recovery control limits for the surrogate are 40 to 150 % recovered. 11.2.1.1 If the recovery is outside of these limits, see Annex A1. 11.2.2 Method Blank--For every 20 samples or batch, whichever is more frequent, a method blank shall be prepared by processing the extraction solvent (with surrogate, if used) through the same clean-up as that used for the samples. This is to detect possible contamination picked up during the sample clean-up process.

t][~

D 6160

NOTE 1 0 - - A batch is the group of samples prepared at the same time. A batch may not exceed 20 samples.

11.2.3 Calibration Check Standard (CCS) (Tier II only)--A 0.1 ug/mL standard (or 0.2 ug/mL) obtained from a source separate from the intermediate standard and containing Aroclors 1016 and 1260 is the CCS which is used to verify the validity of the five-point calibration curve. The calculated results for the CCS shall agree with the current calibration curve to within -+30 % percent difference (% D). If the CCS results indicate that the calibration is outside control limits, and routine maintenance does not correct the problem, then the GC/ECD must be recalibrated. 11.2.4 Matrix Spike (MS) Samples (Tier II only)--For every batch or twenty samples, whichever is more frequent, a sample requiring Tier II analysis shall be selected in an unbiased manner and spiked with Aroclor 1268. These results shall be documented, with an example shown in Appendix X2. 11.2.4.1 1.0 mL of 50 ug/mL of Aroclor 1268 (25 ug/mL, if working at lower calibration range) is added to the sample chosen for spiking. Matrix spiked sample recovery limits are 60 to 140 %, providing any Aroclor present in the sample before spiking does not exceed five times the spike level. Recovered amount % Recovery Spiked amount x 100%

12.2.2.1 If the sample does not totally dissolve, vortex again or place capped vial in sonic bath for 5 min. This shall provide adequate contact whether or not any further dissolution occurs. 12.2.3 Matrix Spike and Matrix Spike Duplicate Samples-Add 1.0 mL of spiking solution to the sample just after the addition of the surrogate and prior to the addition of the acetone-hexane solvent. 12.2.4 Centrifuge--If sediment is visible, centrifuge the extract to separate out the sediment. 12.3 Sample Clean-up--Clean-up is not required for all samples; however, interference problems due to the presence of other chemical species may usually be addressed using the procedures found in Annex A4. 12.4 Gas ChrOmatographic Analysis Sequence--Samples are analyzed in a set referred to as an analysis sequence. 12.4.1 Tier 1-Screening: 12.4.1.1 Standards Sequence (initially and optionally with recalibrations)--(a) Aroclor 1016/1260, at selected IPS level (5 times) and (b) The following may be mixed as described below and shall be analyzed at 0.1 ug/mL each (for 20 mg/Kg level of interest use 0.2 ug/mL). Aroelor Aroclor Aroclor Aroclor Aroclor Aroclor Aroclor

(5)

11.2.5 Matrix Spike Duplicate (MSD) Sample (Tier H only)--Every batch or 20 samples, whichever is more frequent, precision data is generated using a matrix spike duplicate. Acceptance criteria is 20 % RPD (relative percent difference) for the duplicate analyses. 11.2.5.1 RPD is calculated from the absolute difference between duplicate percent recovery results D~ and D 2 divided by the mean value of the duplicates. RPD

-

ID I -- D21 ( ~ - ~ ~)--~72x 100 %

(6)

12. Procedure 12.1 Compositing--It is common to analyze mixtures of multiple samples, called composites, if a large number of samples are analyzed. This approach is described in Annex A3. 12.2 Sample Preparation Procedure: 12.2.1 Liquid Samples--Accurately pipette 3.0 mL of sample into a tared 40 mL vial (fitted with a TFE-fluorocarbonlined cap) and weight. If the results are calculated by weight accurately weigh the sample and record the weight. Spike this sample with 100 uL of decachlorobiphenyl surrogate working standard. 12.2.1.1 Add 27 mL acetone/hexane to the vial, producing a 1:10 dilution. Cap it and vortex vigorously for at least 30 s. If the sample is not completely miscible with acetone/hexane, add more acetone to reach a total of approximately 30 mL extract and vortex again. (Alternatively, place capped vial in sonic bath for 5 min.) 12.2.2 Solid, Semi-solids, Sludge Samples--Weigh accurately 3.0 g of sample into a 40 mL vial fitted with a TFE-fluo'ocarbon-lined cap. Spike this sample with 100 uL of decachlorobiphenyl surrogate working standard. Add 30 mL of acetone/hexane to the vial for a 1: 10 dilution. Vortex for at least 30 s.

1044

1221 1232 1242 1248 1254 1262 1268

12.4.1.2 Some of the standards in 12.4.1.1 may be run as mixed standards: Aroclor

May be Mixed With

1268 1262 1254

1221 or 1232 or 1242 or 1248 or 1254 1221 or 1232 or 1242 or 1248 1221

12.4.1.3 A Typical Analysis Sequence--A typical analysis sequence includes (a) reagent blank (optional), (b) Instrument Performance Standard (IPS) (every 20 samples or every day, whichever is more frequent), (c) method blank, and (d) Samples 1 to 20. 12.4.1.4 Repeat this sequence as long as the system meets the IPS criteria. 12.4.2 Tier 2-Quantitation: 12.4.2.1 Standards Sequence--The standards sequence includes (a) reagent blank, (b) Aroclor 1016/1260 (5 point calibration), (c) Aroclor 1268 mid-level standard, (d) Mid level standard of suspected Aroclors if not, 1016 or 1260, and (e) (CCS, five times, to establish DCB response, if DCB is not spiked in 1016/1260 standards.) 12.4.2.2 A Typical Analysis Sequence--A typical analysis sequence includes (a) reagent blank (optional), (b) CCS (1016/ 1260 mid standard), (c) method blank, (d) Samples 1 to 20, (e) matrix spike sample, and (f) matrix spike duplicate. 12.4.2.3 Repeat this sequence as long as the system meets the quality assurance criteria. 12.5 Inject 2 uL of the sample extract into the gas chromatograph using an autosampler or a manual injection. 12.6 Set the data display (printer or video screen) conditions so that a mid point calibration standard shall be full scale on the chromatogram.

~'~ D 6160 12.7 If the results exceed the calibrated range of the system, and quantitication is desired, the extract shall be diluted and reanalyzed within the calibration range. 13. Calculation 13.1 Screening--Aroclors are made up of numerous congeners and so the chromatograms are multi-peak. Often the chromatogram of the sample may not exactly match that of the standard due to factors such as environmental exposure, interferences not easily removed by cleanup techniques, and the presence of multiple Aroclors. 13.1.1 Visual determinations are made by comparing the chromatogram with the reference chromatograms. Set the data display conditions so that a 0.1 ug/mL standard is full scale on the chromatogram. 13.1.2 All samples in which an Aroclor is detected require a judgment concerning the amount. The recognized Aroclor pattern shall be compared to the IPS (0.01 ug/mL or 0.1 ug/mL). If the overall level of the suspected Aroclor pattern is equal to or greater than the overall level of the IPS pattern, then Tier II analysis may be used to quantitate the PCBs. 13.1.3 If Aroclor identification is prevented by the presence of interferences, additional sample preparation is required. All composites having such interferences shall be analyzed as individual samples. Individual samples may be diluted prior to analysis, but it must be remembered that the detection limit of the analysis has been changed. Used oil samples shall not be diluted beyond 1:100 during initial screening analysis to meet the regulated level of interest (2 ug/mL). 13.1.4 If PCBs are detected, (when compared to the IPS criteria above) the result is reported Positive. If no PCBs are detected above the IPS level, the result is Negative. 13.1.5 When screening for Aroclors, visual determination is made by the following key items: 13.1.5.1 Aroclor P a t t e r n I T h e Aroclor pattern includes (a) Same singlets, doublets, and triplets present in the reference chromatograms, and (b) Same relative peak heights between peaks in the sample chromatogram and the reference chromatogram. 13.1.5.2 Retention times shall be very consistent between the standard and the sample peaks. 13.2 Data System QuantitationiThe GC data system shall be calibrated for each Aroclor using a minimum of five peaks (with exception of Aroclor 1221, which uses three peaks) for each Aroclor. For use with integrators, divide the standard amount by the number of peaks being used (for example, using five peaks on a 0.5 ug/mL standard would assign 0.1 ug/mL to each peak.) For some data systems, the total standard amount may be assigned to each peak. This will allow for a calibration table to be made, yielding response factors for each peak.

Samples exceeding the working range shall be diluted prior to analysis so that quantitation is performed within the calibration range. 13.2.3 As an example, the data system shall be set up to provide results in ug/mL. The following equation yields the concentration of Aroclors in mg/kg on a wet weight basis. Aroclor (mg/kg) (wet) =

Aroclor (ug/mL) Xdilution volume 10 mL sample wt (g) x 1 m-----L(7)

After determining the water content, using Test Method E 203, the concentration of Aroclor in a sample is corrected for dry weight of the sample by the following: Aroclor g/kg (wet) Aroclor mg/kg (dry) = (100 - % water) / 100

(8)

Water content is usually determined by Test Method E 203. 13.3 Manual Quantitation--Quantitate Aroclor samples by comparing the area of five sample peaks (minimum of three, if interferences present) to the area of the same peaks from appropriate (mid level) reference standards. Use only those peaks from the sample that are attributed to Aroclors. These peaks shall be present in the chromatogram of reference materials. See Aroclor Calculation Work Sheet (Appendix X2.) for an example of how to perform manual quantitation. 13.3.1 Use the following formulas to calculate the concentration of each of the Aroclor peaks in the sample (wet weight): Aroclor (wet) Peak No. 1 (ug/mL) = sample area X dilution volume (mL) standard area Xsample volume (mL) X (standardconcentrate ug/mL) X

(9)

dilution volume No. 1 aliquot volume

13.3.2 This is repeated for each peak used, and the results summed to give the wet concentration. The result may be converted from ug/mL to ug/g by: total Aroclor (ug/mL) Aroclor (ug/g) = specific gravity of sample

(10)

Specific gravity may be the measured value or calculated by (sample weight/3 mLs). Care shall be taken in handling viscous samples as the volumes may not be correct. In those cases the measured sample weight shall be used. A simplified formula using sample weight is: Aroclor (ug/g, mg/Kg) = totalAroclor (ug/mL) × dilution volume (mL) X additional dilution factor(mL/mI sample weight (g) (11) The concentration of Arocior in a sample is corrected for dry weight of the sample by the following:

NoTE l 1--Response factors are based on amount/area for some data systems, while response factors are based on area/amount for others.

Aroclor (mg/Kg) (wet) Aroclor (mg/Kg) (dry) = (100 - % water) / 100

13.2.1 Quantitation of Aroclor in samples requires selecting five peaks that are free of interferences (minimum of three peaks, if interferences present) in the TIER II analysis, and assigning the appropriate response factor to each peak. 13.2.2 Aroclors 1016/1260 are quantitated using a five point calibration. All other Aroclors use a single point calibration.

13.4 Mixed Aroclors--For routine Tier II samples showing evidence of mixed Aroclors, select a minimum of three peaks lacking significant interference for each identified Aroclor and quantitate. Report the amount for each Aroclor separately.

1045

(12)

NOTE 12--This approach will normally overstate the PCB concentration and, thus, is considered to be a conservative approach.

(~'~ D 6160 13.4.1 Since mixed Aroclors present special problems in quantitation, it is permissible to prepare individualized mixed standards in an attempt to match the suspected sample concentrations and obtain greatest possible accuracy. This will involve a judgment about what proportion of the different suspected Aroclors to combine to produce the appropriate reference material. A calibration standard is then made using this blend. Use only those peaks from the sample that are attributed to chlorobiphenyls. These peaks shall be present in the reference blend. 14. Precision and Bias

14.1 The precision of this test method was determined by statistical examination of interlaboratory study results. All data was generated using GC/ECD. 14.1.1 Repeatability--The difference between two results obtained by the same operator with the same apparatus under constant operating conditions on identical test materials would, in the long run, in the normal and correct operation of the test method exceed the following values only one case in twenty: Repeatabdity = 0.16 (X I i).

working in different laboratories on identical materials would in the long run, exceed the following values only in one case in twenty. Reproducibility = 0.73 (X t 1).

(14)

where X is the average PCB concentration in mg/kg. 14.1.3 Precision estimates for selected values of X are set out in the following Table 1: 14.2 Bias--A reliable quantitation of bias was not possible due to the manner in which the samples were prepared and aliquoted. However, the method tends to produce a result that is low. This tendency is mitigated to some extent through the use of a surrogate as described in Section 11. 15. Keywords 15.1 gas chromatography; GC/ECD; PCBs; polychlorinated biphenyls

TABLE 1 Repeatability and Reproducibility

(13)

where X is the average PCB concentration in mg/kg. 14.1.2 Reproducibility--The difference between two single and independent results obtained by different operators

x, rng/kg

Repeatability

Reproducibility

5 10 20 50

0.9 2.0 4.3 11.8

4.3 9.4 20.2 55 5

ANNEXES (Mandatory Information) A1. POOR RECOVERY TROUBLESHOOTING

Al.l If the necessary recovery is outside of limits, the following may be useful in identifying the source of the problem: AI.I.1 Al.l.2 A1.1.3 A1.1.4 Al.1.5 A1.t.6 and

Check for proper dilution factor, Check for dirty insert and drifting baseline, Recheck the recovery calculation, Look for major interfering peak, Look for sample preparation problems, Reanalyze sample, on different channel, if possible,

AI.I.7 Re-evaluate surrogate standard. A1.2 If none of the above results in acceptable surrogate recoveries: A I.2.1 Break composites into individual samples, prepare samples, and reanalyze. A1.2.2 For individual samples, if the recovery is still outside of the limits after a second preparation and analysis, this demonstrates confirmation of a matrix effect and is reported as such.

A2. SILYNIZATION

A2.1 There are many possible pathways to deactivate glass surfaces. These are basically divided into vapor and liquid methods. Two examples follow: A2.2 Liquid Silylation: A2.2.1 Prepare 5 % (volume) solution dimethyldichlorosilane in toluene. A2.2.2 Place the clean glass parts to be treated in wide-mouth jar or beaker large enough to allow the solution cover the parts. A2.2.3 Heat the solution with the glass part submerged

the boiling point and continue gentle boiling for 30 min. A2.2.4 Allow the parts to drain and rinse with methanol. A2.2.5 Oven dry the glass parts at 100°C for at least 20 min. A2.3 Vapor Silylation:

of a to to 1046

A2.3.1 A2.3.2 the jar. A2.3.3 preheated A2.3.4

Place the clean glass parts in a wide-mouth glass jar. Add 1 mL of concentrated dimethyldichlorosilane to Screw a lid on the jar and place it in an oven to 50°C for at least 2 h. Remove jar and open lid.

t~

D 6160

A2.3.5 Rinse glass parts with methanol. A2.3.6 Oven dry the glass parts at 100°C for at least 20 minutes,

A2.4 Silanized glass parts shall be stored in the oven or in a desiccator with activated desiccant in the bottom until needed.

A3. COMPOSITING

A3.1 It is common to analyze mixtures of multiple samples, called composites, if a large number of samples are analyzed. Positive identification of PCBs within a composite usually then requires that the individual samples making up the composite be re-analyzed individually to identify the source of the PCBs. A3.1.1 If samples are to be run as a composite, rather than individually, transfer 1 mL of a representative portion of each sample (1 g, if a solid) into a vial by means of disposable pipet. Larger volumes than 1 mL may be used, if required by sample matrix to obtain a representative sample. Mix them well to get a composite of up to ten samples. If using the surrogate, be sure to consider the dilution factor. A3.1.2 Compositing of Samples Representing Varying

Volumes A3.1.2.1 If receipt samples representing varying volumes (for example, multiple partially-filled drums) are to be

composited, it is important to ensure that each unit volume (for example, each litre) is equally represented. If preliminary composites have been generated outside of the laboratory, the analyst making the composite will need to understand the volume of material represented by each sample. A3.1.2.2 The composite is generated by using a pipette to transfer proprotional amounts(for example, 1 mL/drum) into a vial. For example, if a sample entering the laboratory represents eight drums, place 8 mL of that sample in the vial. Assuming the 20 drum maximum is reached, place 20 mL of material in the vial. Vortex well. A3.2 When Aroclor is detected in a composite at a level equal to or above the IPS, all samples included in the composite shall be analyzed individually.

A4. SAMPLE CLEAN-UP

magnesium silicate clean-up, substituting silica gel for magnesium silicate. Samples that have undergone acid clean-up and magnesium silicate slurry and that still display interferences shall undergo an additional silica gel slurry cleanup. The extract, after acid and magnesium silicate slurry clean-up, is pipetted to a 20-mL vial containing 0.5 g silica gel and vortexed. Further information can be found in EPA Method 3630.

A4.1 Clean-up is not required for all samples; however, the following clean-up procedures will solve most interference problems to obtain analyzable chromatograms. Use the particular clean-up method demonstrated to yield acceptable results, if a lab is familiar with the type of matrix in their samples. A4.2 Magnesium SilicateSlurry and Acid Clean-Up (Individual Samples)--Pipet 1.0 mL of the 1:10 diluted extract to a 20 mL vial containing 9.0 hexane. Further information is provided in EPA Method 3620.

A4.4 Magnesium Silicate Column Clean-up:

NOTE A4.1--For Composited Sample (see Annex A3)--No further dilution required beyond the initial 1:10, unless sample matrix requires it. Further dilutions may cause detection limits to rise above the level of interest. A4.2.1 Add 3 mL concentrated sulfuric acid to the solution. Cap it with a TFE-fluorocarbon-lined cap and vortex well. Let it settle to allow phase separation. More than one acid clean-up may be used if the acid layer is discolored after phase separation. Record the number of washings performed. A4.2.2 Transfer about 8 mL of this solution (free from acid) into another 20 mL vial, containing about 0.25 g magnesium silicate and 0.5 g of anhydrous sodium sulfate. For used oil samples it may be preferable to use 0.25 g anhydrous sodium sulfate and 0.5 g silica gel. Vortex well and allow the magnesium silicate to settle by gently tapping the vial or by centrifuging for about 2 min. A4.2.3 The final solution after clean-up is transferred into a GC vial.

A4.4.1 Plug a 10 mL disposable pipet with glass wool. Add the equivalent depth of 1 mL anhydrous sodium sulfate. Add the equivalent depth of about 2 mL magnesium silicate. Top off the column with the equivalent depth of 1 mL anhydrous sodium sulfate. Tap the column gently. Optionally, one may use a commercial clean-up cartridge (1000 mg packing). A4.4.2 Put a container beneath the column to catch the eluate. Wet with 2 to 3 mLs hexane. Transfer 1 to 2 mLs of the acid cleaned sample to the column.

A4.3 Silica Gel Slurry Clean-Up--Follow the procedure for 1047

NOTE A4.2--Caution: Do not allow any acid to go into the column. A4.4.3 Discard the eluate. When the extract level reaches the top of the upper sodium sulfate, add 5 mL more of the extract into the column. Collect the eluate in a GC autosampler vial. A4.5 Combined Magnesium Silicate and Silica Gel Column Clean-up--Prepare a silica gel column using a 10-mL disposable pipet plugged with glass wool. On top of the glass wool place 1 mL silica gel. Add to the column about 1 mL magnesium silicate and then 1 mL anhydrous sodium sulfate.

(@) D 6160 Tap the column gently. Transfer 5 mL of already acid cleaned sample to wet column (see EPA Method 3620)

peaks. Check for sample history for the presence of sulfur. To remove the sulfur, transfer 5 mL of the extract into a vial, add 1 drop of mercury, seal, and vortex vigorously. Allow the mercury sulfate to settle. Remove about 4 mL of the hexane solution and perform an acid wash to clear the hexane phase. Further information can be found in EPA Method 3660.

A4.5.1 Discard the eluate. When the extract level reaches the top of the upper sodium sulfate, add about 3 mL more of the extract. Collect about 2 mL in a GC vial. A4.6 Mercury Clean-Up--Elemental sulfur in samples will cause interferences in the GC/ECD analysis. Presence of sulfur will be indicated by a yellow extract color and big interfering

NOTE A 4 . 3 - - W a r n i n g : Handle mercury with care. Keep a minimum amount on site.

APPENDIXES (Nonmandatory Information) X1. EXAMPLE CALIBRATION TABLE AND CHROMATOGRAM X 1.1 See Table X 1.1 for an example calibration table and chromatogram. X1.2

Aroclors 1016 and 1260. The five peaks for each Aroclor used for quantitation are clearly marked (for example, 7.295-1016). X1.2.2 The decachlorobiphenyl surrogate internal standard is also shown and designated as 15.220-DCB. X1.2.3 This chromatogram was generated using the longer run time described in 10.1.2.

Chromatogram:

X1.2.1 The chromatogram in Fig. XI.1 includes the retention time in minutes for each major peak in a mixture of TABLE X1.1

Calibration Table

Retention

Peak

Average

Standard

Peak

~me

Name

Response

Deviation

% RSD

7.520 7.870 8.390 10.150 10.540 11.540 11.930 12.370 13.430 13.880

1016 1016 1016 1016 1016 1260 1260 t260 1260 1260

4543228 2743429 6378927 1851507 1919245 4325072 6012570 5503749 5830717 3118738

528055 214966 360623 129351 150403 493032 639705 470809 428980 164338

11.62 7.84 5.65 6.99 7.84 11.40 10.64 8.57 7.36 5.27

1048

~ D 6160

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X2. WORKSHEETS

X2.1 See Fig. X2.1 and Fig. X2.2 for calculation worksheets.

1050

~ GC I D E N T I F I C A T I O N : CONTROL#

D 6160

CHANNEL#

GC#

SAMPLE

AROCLOR STANDARD: ANALYST/DATE: REVIEWER/DATE:

PEAK #

UG/ML

R.T. (MIN)

AREA

PEAK #

i.

1

2.

2

3

3

4.

4.

5.

5.

TOTAL

AREA

R.T. (MIN)

TOTAL

CALCULATION: 25 u g / m L THEOR.

PCB S P K

**EXPERIMENTAL

(AR 1268)

RESULT

X 1.0 m L = 0.0806 3 1 . 0 m L X 10 m L

=

TOTAL

SAMPLE AREA

TOTAL

STANDARD

=

X STANDARD AREA X 0.i u g / m L ug/mL EXPERIMENTAL

% RECOVERY

OF AR

1268

X

=

X 0.0806

**AFTER

SUBTRACTING

RESULT

= THEORETICAL

PCB

%

I00 =

IN THE

SAMPLE.

FIG. X2.1 PCB Calculation Work She~ for Spi~s

1051

i00

RESULT

ug/mL

BACKGROUND

=

ug/mL

CONC

@

SAMPLE

CONTROL

LAB#:

# :

GC S Y S T E M

IDENTIFICATION

COLUMN

:

ID

o 6160

:

30 m R T X - 5 (or DB-5), 0.32 m m ID c a p i l l a r y w i t h 0.25 D m film t h i c k n e s s . INSTALLED AROCLOR

TYPE

:

AROCLOR

STD

:

STD PEAK R.T.

i

BY / D A T E

STD PEAK AREA

column,

:

Dg/mL

STD AMT/ Dg/mL

RF AMT AREA

ANALYST

/ DATE

:

REVIEWER

/ DATE

:

SAMPLE PEAK R.T.

SAMPLE PEAK AREA

SAMPLE PEAK AMT (AREA* R F )

•

2. 3. 4. 5. Total A r o c l o r Calculation: = Aroclor

(

Amt

Aroclor

Concentration

in m g / K g

(Dg/mL) X Dil. V o l u m e m L X Dil. S a m p l e W e i g h t (g)

Amount

(Dg/mL)

(Dg/g) Factor

) mg/Kg

of A r o c l o r

% W a t e r (By K a r l - F i s c h e r / N V R / S p e c i f i e d Other) % Dry Weight A r o c l o r C o n c e n t r a t i o n C o r r e c t e d For D r y W e i g h t FIG. X2.2 AROCLOR CalculationWork She~

1052

= = =

% % mg/Kg

o 6160 The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection w~th any item menhoned m this standard. Users of this standard are expressly advised that determination of the vahdity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibili~ Thts standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reapproved or wtthdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you should make your wews known to the ASTM Committee on Standards, 100 Barr Harbor Drive, West Conshohocken, PA 19428.

1053

(~l~ Designation: D 6212- 97 Standard Test Method for Total Sulfur in Aromatic Compounds by Hydrogenolysis and Rateometric Colorimetry 1 This standard is issued under the fixed designation D 6212; the number immediately following the designation indicates the year of onginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (e) indicates an editorial change since the last revision or reapproval.

1. Scope 1.1 This test method covers the determination of sulfur in aromatic hydrocarbons, their derivatives, and related chemicals having typical sulfur concentrations from 0.020 to 10 mg/kg. 1.2 This test method may be extended to higher concentrations by dilution. 1.3 This test method is applicable to aromatic hydrocarbons and related chemicals such as benzene, toluene, cumene, p-xylene, o-xylene, and to cyclohexane. 1.4 The following applies to all specified limits in this test method: for purposes of determining conformance with this standard, an observed value or a calculated value shall be rounded off to the nearest unit in the last right-hand digit used for expressing the specification limit in accordance with the rounding-off method of Practice E 29. 1.5 This standard does not purport to address all the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.Specific prcautionary statements are given in 6.4, 7.5, 7.7, and 8.1.

2. Referenced Documents 2.1 ASTM Standards." D 1193 Specification for Reagent Water2 D 3437 Practice for Sampling and Handling Liquid Cyclic Products 3 D 4045 Test Method for Sulfur in Petroleum Products by Hydrogenolysis and Rateometric Colorimetry4 D 4052 Test Method for Density and Relative Density of Liquids by Digital Density Meted D 4790 Terminology of Aromatic Hydrocarbons and Related Chemicals 3 E 29 Practice for Using Significant Digits in Test Digits in Test Data to Determine Conformance with Specifications5 2.2 Other Documents." 1 This test method is under the jurisdiction of ASTM Committee D 16 on Aromatic Hydrocarbons and Related Chemicals and is the direct responsibility of Subcommittee D 16OE on Instrumental Analysis. Current edition approved December 10, 1997. Published April 1998. 2 Annual Book o/ASTM Standards, Vol 11.01. 3 Annual Book of ASTM Standards, Vol 06.04. 4 Annual Book of ASTM Standards, Vol 05.02. 5 Annual Book o f ASTM Standards, Vol 14.02.

OSHA Regulations, 29 CFR paragraphs 1910.12006

1910.1 and

3. Terminology 3.1 See Terminology D 4790 for definition of terms used in this test method.

4. Summary of Test Method 4.1 Reductive Configuration---The sample is injected at a constant rate into a hydrogenolysis apparatus. Within this apparatus the sample is pyrolyzed at temperatures in the range ofl200°C to 1300°C and in the presence of excess hydrogen. Sulfur compounds are reduced to hydrogen sulfide (HES). Analysis is by rateometric detection of the colorimetric reaction of HES with lead acetate. Hydrocarbon components are converted to gaseous such as methane during hydrogenolysis. 4.20xyhydroPyrolysis Configuration--Sample is injected at a constant rate into an air stream and introduced into a pyrolysis furnace. The sample flows through an inner tube within the furnace where it combusts with the oxygen in the air carrier. SO 2 and SO 3 are formed from the sulfur compounds in the sample. The sample then leaves the inner tube within the pyrolyzer and is mixed with hydrogen within the main reaction tube and is pyrolyzed at temperatures in the range of l 200°C to 1300°C (see Fig. 1 ). The SO 2 and SO 3 formed within the inner tube are then reduced to H2S. Analysis is by rateometric detection of the colorimetric reaction of H2S with lead acetate. 5. Significance and Use 5.1 Sulfur can be a catalyst poison in the aromatic chemical manufacturing process. This test method can be used to monitor the amount of sulfur in aromatic hydrocarbons. This test method may also be used as a quality control tool and in setting specifications for sulfur determination in finished products. 6. Apparatus 6.1 The apparatus of this test method can be setup in two different configurations, which will be described herein as the "reductive pyrolysis" configuration, and the "oxyhydropyrolysis" configuration. The reductive pyrolsis configuration is the

Available from Superintendent of Documents, U.S. Government Printing Office, Washington, DC 20402.

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D 6212 one referenced in Test Method D 4045. The oxyhydropyrolysis configuration is a modification of the reductive pyrolysis configuration that minimizes the formation of coke within the pyrolysis furnace when running aromatic samples. Both setups can be used to measure sulfur in aromatic compounds as outlined in this test method. 6.2 Pryolysis Furnace--A tube furnace that can provide an adjustable temperature of 900 to 1400°C. An 8-mm or larger inner diameter is required in the furnace to fit reaction tubes of sufficient size to pyrolyze the sample. 6.2.10xyhydrogen Furnace Adapter--An apparatus, used in the oxyhydropyrolysis set up, that fits to the front of the reaction tube and adds an injection tube that extends partially within the main reaction tube to about 1/2 way into the furnace (see Fig. 1). The oxidative process occurs in the injection tube, then the combustion products of the sample are injected into the flow of hydrogen at the hot zone. 6.2.2 Water Removal Apparatus--A device that attaches close to the outlet of the pyrolysis furnace, used in the oxyhydropyrolysis set up to remove excess moisture from the sample stream. Both membrane counter flow driers or coalescing filters held at sub-ambient temperatures have been found to be suitable. 6.3 Rateometric H2S Detector--Hydrogenolysis products contain H2S in proportion to sulfur in the sample. The HzS is measured by measuring rate of change of reflectance caused by darkening when lead sulfide is formed. Rateometric electronics, adapted to provide a first derivative output, allows sufficient sensitivity to measure below 0.01 mg/L. 6.4 Hypodermic Syringe-- A hypodermic having a needle long enough to reach into the pyrolyzer reaction tube to the 550°C zone is required. Usually a 75-mm long needle is sufficient for the straight reductive setup. The oxyhydropyrolsis setup requires a needle length of 150 mm. A side port is convenient for vacuum filling and for flushing the syringe. A 100-1aL syringe is satisfactory for injection rates down to 3 laL/ min. and a 25-1aL syringe for lower rates.

all reagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, where such specifications are available. 7 Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination. 7.2 Purity of Water--Unless otherwise indicated, reference to water shall be understood to mean Type II, reagent grade water, conforming to Specification D 1193. 7.3 Sensing Tape--Lead-acetate-impregnated analyticalquality filter paper shall be used. 7.4 Acetic Acid (5 %)--Mix 1 part by volume reagent grade glacial acetic acid with 19 parts water to prepare 5 % acetic acid solution. 7.5 Hydrogen Gas--Use sulfur-free hydrogen of laboratory grade. NoN 2--Warning: Hydrogen has wide explosive limits when mixed with air. 7.6 Purge Gas--Sulfur-free purge gas, nitrogen, CO2, or other inert gas. Commercial grade cylinder gas is satisfactory. 7.7 Instrument Air--Use dry, sulfur-free air. Nitrogen/ oxygen, or helium/oxygen bottled gas blends containing no more than 30 % oxygen by volume can be used where air utilities are not available. NOTE 3--Warning: Do not use pure oxygen as a substitute for instrument air. 7.8 Toluene, (sulfur free). 7.9 Thiophene, 99+ % purity. 8. Hazards 8.1 Consult current OSHA regulations, suppliers Material Safety Date Sheets, and local regulations for all materials used in this test method. 9. Sampling 9.1 Use the practices in accordance with Practice D 3437.

NOTE 1 - - W a r n i n g : Exercise caution as hypodermics can cause accidental injury.

6.5 Syringe Injection Drive---The drive must provide uniform, continuous sample injections. Variation in drive injection rate caused by mechanical irregularities of gears will cause noise in the reading of the detector. The adjustable drive must be capable of injection rates from 6 ~tL/min. to 0.06 taL/min. over a 6-min interval. 6.6 Recorder--A chart recorder with 10-V full scale and 10 kl~ input impedance or greater is required, having a chart speed of 0.5 to 3 crn/min. An attenuator may be used for more sensitive recorders. 6.7 Pyrometer--A pyrometer with a 25-cm long thermocouple suitable for use at 500 to 1400°C. Diameter must be small enough to fit through the injection tube of the oxyhydrogen furnace adapter. Type K with a 316 stainless steel sheath is suitable. 7. Reagents and Materials

7.1 Purity of Chemicals--Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that

10. Calibration Standards 10.1 Prepare a reference standard solution or solutions of strength greater than that expected in the unknown, by first preparing a stock solution of thiophene in toluene and volumetrically diluting the stock to prepare low level standards. 10.2 Preparation of the Stock Standard Solution: To prepare a sulfur standard with a sulfur concentration of 1000 mg/ L, obtain a clean 100-mL volumetric flask. Pour approximately 90 mL of toluene (sulfur free), kept at a room temperature of 25°C, into the flask. Weigh approximately 0.2625 g (250 ~tL) of thiophene directly into the flask and record the exact weight added to a precision of +_ 0.I rag. Add additional toluene to make 100.0 mL.

7Reagent Chemicals, American Chemical Society Specifications,American Chemical Society, Washing ton, DC. For suggestions on the testing of reagents not listed by the American Chemical Society, see Analar Standards for Laboratory Chemicals,BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeial and National Formulary,U.S. Pharmaceutical Convention, Inc. (USPC), Rockville, MD.

1056

~1'~ D 6212 10.3 Calculate the sulfur concentration of the stock solution as follows: B .4 = ~-T-~D

(1)

where: A = concentration of sulfur in mg/L, B = molecular weight of sulfur: 32.06, C = molecular weight of thiophene: 84.14, and D = exact weight of the sulfur compound used in milligrams. 10.4 Preparation of Working Standards The preparation of working standards is accomplished by volumetric dilution of the stock solution. As an example, to prepare a 1.00--mg/L standard, dilute 0.10 mL of the 1000-mg/L stock solution into 100 mL of toluene (sulfur free). Keep containers closed as much as possible. Do not open containers of pure sulfur compounds in the vicinity of low level calibration standards. NoN 4---The use of standard samples made to mg/L units have the advantage of delivering a specificnumber of milligrams of sulfur into the analyzer for a specific sample size regardless of the sample compound used. A standard of one type of compound could be used to calibrate the analyzer, with an unknown of another type of sample compoundrun. To determine the sulfur content of the unknown in mg/kg simply divide the mg/L answer by the density (expressedin g/mL) of the unknown sample. 11. Set-Up Apparatus 11.1 Straight Reductive Setup---Connect apparatus as shown in Fig. 2. Fill humidifier bubbler inside the cabinet with 5 % by volume acetic acid solution. Install sensing tape and turn on detector. Connect the recorder. Set pyrolysis furnace temperature to 1200°C and allow system to come to temperature. Purge system with inert gas, and check all connections for leaks with soap solution. Stop flow of inert gas and allow temperature to stabilize. Ifmonoaromatics Of Clo or

lower are to be run, make final pyrolyzer temperature adjustment to 1215 +_ 15°C. For all other aromatic compounds, make final pyrolyzer temperature adjustment to 1315 +-- 15°C. Use a standard thermocouple to verify temperature by inserting through a septum with the hydrogen flowing at the rate used for .analysis. Determine depth of insertion required with the pyrometer (measure temperature with gases flowing) and always insert the needle tip to a depth corresponding to the 550°C point. 11.20xyhydropyrolysis Setup----Connect apparatus as shown in Fig. 3. Fill humidifier inside the cabinet with 5 % by volume acetic acid solution. Set pyrolysis furnace temperature to 1200°C and allow system to come to temperature. Purge system with inert gas and check all connections for leaks with soap solution. Stop flow of inert gas and allow temperature to stabilize, l f monoaromatics of Cto or lower are to be run, make final pyrolyzer temperature adjustment to 1215 +_ 15°C. For all other aromatic compounds make final pyrolyzer temperature adjustment to 1315 +_ 15°C. Use a standard thermocouple to verify temperature by inserting through a septum with the hydrogen flowing at the rate used for analysis. Determine depth of insertion required with the pyrometer (measure temperature with gases flowing) and always insert the needle tip to a depth corresponding to the 550°C point. 11.3 Adjust the zero of the analyzer (and recorder if used) to

its desired position with no flow. This should be performed with span at maximum. Skip this step if the analyzer is computerized and automatically sets its own zero level. 11.4 Test Hydrogen Purity---Set the hydrogen flow to 200 mL/min. Advance tape to a new spot. If the reading is upscale from the zero set point by greater than 4 % full scale, then the hydrogen source should be suspect as not being sulfur free and should be changed or scrubbed. 11.5 If the change in the reading is less than 4 %, reset analyzer zero with the hydrogen flowing. This will compensate for the small amount of sulfur in the hydrogen. 11.6 For apparatus configured in the oxyhydropyrolysis setup, also test air purity. This is done by maintaining the hydrogen flow at 200 mL/min, and setting the air flow to 250 mL/min. If the reading is upscale from the zero set point by greater than 4 %, then the air source should be suspect as not being sulfur free and should be changed or scrubbed. 11.7 If the changes in the reading is less than 4 %, reset analyzer zero with the hydrogen and air flowing. This will compensate for the small amount of sulfur in the hydrogen and air. 12. Calibration 12.1 Advance tape and inject a working standard solution with a sulfur concentration similar to the highest expected value of the unknown samples. Set the plateau of the response curve (see Fig. 4 ) to approximately 90 % of the recorder's span. This working standard should be analyzed in triplicate to ensure the analyzer has stabilized. Replicate analyses should not differ by more than 5 % relative. Record the average reading as Rstd in 14.1. If the analyzer is computerized, follow calibration steps as indicated in manufacturer's instruction. 12.2 Analyze a working standard that has a concentration 100 times less than the standard used in 12.1. This will be the lower limit of detection for the instrumental conditions used in the testing and should produce a barely discernable response from the recorder. 12.3 Analyse the solvent used to make the working standards, or run analysis without injecting any sample in order to obtain a blank reading. Record this reading as R b in 14.1 . 13. Procedure 13.1 Advance the tape and inject the unknown sample. After a stable reading is obtained, determine the plateau of the response curve (see Fig. 4). Record this value as R s. If analyzer is computerized, read analysis answer from readout, and record. 13.2 Proceed with additional samples, advancing the tape each time. 13.3 Every 2 h, or as needed, verify blank and span values. 13.4 To measure samples below 1 mg/kg, inject the sample at the fastest rate that does not cause coking in the reaction tube. Higher injection rates will aid in obtaining the best signal to noise ratio. 13.5 Samples above 1 mg/kg require proportionally lower inject rates, span adjustment, or a smaller syringe. A sharp fall in response at high sulfur levels indicates color saturation of the tape. Use a smaller syringe or a slower injection rate, or both, to lessen color saturation.

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TABLE 1 Densities of Aromatics A

C~;td

0.8765 0.8618 0.7785 0.8611 0.8669

Benzene Cumene Cyclohexane p-Xylene Toluene

= concentration of sulfur in standard sample, mg/L, = response of unknown sample, = response of blank run using no sample or solvent Rh known to be sulfur free, = response of standard reference sample, and Rstd Stag L = concentration of sulfur in the sample, mg/L. 14.2 Report reading in mg/kg of sulfur as follows: '

Rs

A Dens~tzes are at 20°C relative to water at 4°C. From CRC Handbook of Chemistry and Physics 72 nd Edition, CRC Press, Inc.

TABLE 2 ResultsBased on Using a 1 ppmwtStandard of Thiophene in Benzene Analysis No.

Peak height, mm

1 2 3 4 5 6 7 8 9 10 11

105 104 107 105 106 107 109 108 109 108 110

Average Standard Deviation

Value, (ppm)

107 1.9

(3)

0.98 0.97 1.00

where density is the appropriate value obtained from Table 1. Alternatively, density may be determined by using Test Method D 4052 at 25°C.

1.00 1.02 1.01 1.02

14.3 Report the sample value to the nearest 0.01 for a sample analysis indicating no sulfur, report the sulfur content as less than the value of the lower calibration standard used in 12.2.

0.98 0.99

1.01 1.03 1.00 0.02

14. Calculation NOTE ~ o m p u t e r i z e d analyzers may do the following calculations internally as part of their analysis procedure and output their answers already presented in appropriate reporting units.

14.1 Calculate the concentration of sulfur as follows: c, ( R s - Rb) SmgL = ~st ( R . ~ R ~ } k std-- b!

Smgkg : C°ncentralt°nmgL Densityg, nL

(2)

15. Precision and Bias 15.1 Intermediate Precision~Intermediate precision has been determined as shown in Table 2. 15.2 Reproducibility--The reproducibility of this test method is being determined. 16. Keywords 16.1 aromatic; aromatic compounds; benzene; colorimetry; cumene; cyclohexane; pyrolysis; rateometry; sulfur; toluene; trace total sulfur

The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly adwsed that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend, ff you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 100 Barr Harbor Drive, West Conshohocken, PA 19428.

1061

IIBOIIT ALBERT

TtttZ W.

IIlTI:Itt DREWS

ince retirement in 1994 from the UOP Research Center in Des Plaines, IL, Albert W. Drews has served as a consultant for AC Analytical Controls. Mr. Drews started working for UOP in 1960 following his graduation from Elmhurst College (IL) with a B.S. degree in chemistry. He held the positions of Supervisor of the Gas Chromatography Laboratory, Manager of the Analytical Laboratories and Manager of Method Development. His career has focused on the analytical analysis of petroleum products and catalysts, with an emphasis on gas chromatography and physical testing. Mr. Drews has been associated with ASTM activities for 38 years with active m e m b e r s h i p in Committee D02 on Petroleum Products and Lubricants since 1976. He has served as author of n u m e r o u s methods and practices, editor, subcommittee chairman, first vice-chairman of Committee D02 and as a m e m b e r of the Committee on Standards. Drews has been h o n o r e d w i t h n u m e r o u s ASTM awards i n c l u d i n g the Committee D02 Scroll of A c h i e v e m e n t , the Award of Excellence, Honorary D02 Membership, the Lowrie B. Sargent, Jr. Medal, and the ASTM Award of Merit. Drews continues his active participation in Committee D02 w h i l e enjoying the benefits of retirement.

ISBN

0-8031-2080-X