ASTM_D_6968_-_03_2015.pdf

Designation:D696803(Reapproved 2015)Standard Test Method forSimultaneous Measurement of Sulfur Compounds andMinor Hydrocarbons in Natural Gas and Gaseous Fuels byGas Chromatography and Atomic Emission Detection1This standard is issued under the fixed designation D6968;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method is for the determination of volatilesulfur-containing compounds and minor hydrocarbons in gas-eous fuels including components with higher molar mass thanthat of propane in a high methane gas,by gas chromatography(GC)and atomic emission detection(AED).Hydrocarbonsinclude individual aliphatic components from C4to C6,aro-matic components and groups of hydrocarbons classifiedaccording to carbon numbers up to C12at least,such as C6-C7,C7-C8,C8-C9and C9-C10,etc.The detection range for sulfurand carbon containing compounds is approximately 20 to100 000 picograms(pg).This is roughly equivalent to 0.04 to200 mg/m3sulfur or carbon based upon the analysis of a 0.25mL sample.1.2 This test method describes a GC-AED method employ-ing a specific capillary GC column as an illustration for naturalgas and other gaseous fuel containing low percentages ofethane and propane.Alternative GC columns and instrumentparameters may be used in this analysis optimized for differenttypes of gaseous fuel,provided that appropriate separation ofthe compounds of interest can be achieved.1.3 This test method does not intend to identify all indi-vidual sulfur species.Unknown sulfur compounds are mea-sured as mono-sulfur containing compounds.Total sulfurcontent of a sample can be found by summing up sulfur contentpresent in all sulfur species.1.4 This method is not a Detailed Hydrocarbon Analysis(DHA)method and does not intend to identify all individualhydrocarbon species.Aliphatic hydrocarbon componentslighter than n-hexane,benzene,toluene,ethyl benzene,m,p-xylenes and o-xylene(BTEX)are generally separated andidentified individually.Higher molar mass hydrocarbons aredetermined as groups based on carbon number,excludingBTEX.The total carbon content of propane and higher molarmass components in a sample can be found by summing upcarbon content present in all species containing carbon.1.5 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.6 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2D1265 Practice for Sampling Liquefied Petroleum(LP)Gases,Manual MethodD1945 Test Method for Analysis of Natural Gas by GasChromatographyD1946 Practice for Analysis of Reformed Gas by GasChromatographyD3609 Practice for Calibration Techniques Using Perme-ation TubesD4626 Practice for Calculation of Gas ChromatographicResponse FactorsD5287 Practice for Automatic Sampling of Gaseous FuelsD5504 Test Method for Determination of Sulfur Compoundsin Natural Gas and Gaseous Fuels by Gas Chromatogra-phy and ChemiluminescenceD5623 Test Method for Sulfur Compounds in Light Petro-leum Liquids by Gas Chromatography and Sulfur Selec-tive DetectionD6228 Test Method for Determination of Sulfur Compoundsin Natural Gas and Gaseous Fuels by Gas Chromatogra-phy and Flame Photometric DetectionE840 Practice for Using Flame Photometric Detectors in GasChromatography1This test method is under the jurisdiction ofASTM Committee D03 on GaseousFuels and is the direct responsibility of Subcommittee D03.05 on Determination ofSpecial Constituents of Gaseous Fuels.Current edition approved June 1,2015.Published July 2015.Originally approvedin 2003.Last previous edition approved in 2009 as D696803(2009).DOI:10.1520/D6968-03R15.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 2.2 Other References:ISO 19739 Natural GasDetermination of Sulfur Com-pounds by Gas chromatography3GPA 2199 DeterminationSpecific Sulfur Compounds4“Improved Measurement of Sulfur and Nitrogen Com-pounds in Refinery Liquids Using Gas ChromatographyAtomic Emission Detection,”Journal of Chromato-graphic Science,36,No 9,September,1998,p.435.3.Terminology3.1 Abbreviations:3.1.1 Acommon abbreviation of hydrocarbon compounds isto designate the number of carbon atoms in the compound.Aprefix is used to indicate the carbon chain form