ASTM_D_7493_-_14.pdf

Designation:D749314Standard Test Method forOnline Measurement of Sulfur Compounds in Natural Gasand Gaseous Fuels by Gas Chromatograph andElectrochemical Detection1This standard is issued under the fixed designation D7493;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 on-line measurement of volatilesulfur-containing compounds in gaseous fuels by gas chroma-tography(GC)and electrochemical(EC)detection.This testmethod is applicable to hydrogen sulfide,C1 to C4 mercaptans,sulfides and tetrahydrothiophene(THT).1.1.1 Carbonyl sulfide(COS)is not covered in this testmethod.1.1.2 The detection range for sulfur compounds is approxi-mately from 0.1 to 100 ppmv(mL/m3)or 0.1 to 100 mg/m3.The detection range may vary depending on the sampleinjection volume,chromatographic peak separation and thesensitivity to the specific EC detector.1.2 This test method describes a GC-EC method employingpacked GC columns and a specific detector for natural gas andother gaseous fuel composed of mainly light(C4 and smaller)hydrocarbons.Alternative GC columns,detector designs andinstrument parameters may be used,provided that chromato-graphic separation,quality control and measurement objectivesneeded to comply with user,or regulator needs or both,areachieved.1.3 This test method does not intend to identify and measureall individual sulfur species,and is mainly employed formonitoring naturally occurring reduced sulfur compoundscommonly found in natural gas and fuel gases or employed asan odorant in these gases.1.4 The test method is typically employed in repetitive orcontinuous on-line monitoring of sulfur components in naturalgas and fuel gases using a single sulfur calibration standard.Need for a multipoint calibration curve or quality controlprocedures can be satisfied by making use of proceduresdelineated in Test Methods D5504,D5623,D6228,D6968,ISO 19739,or GPA 2199.1.5 The test method can be used for measurement of allsulfur compounds listed in Table 1 in air or other gaseousmatrices,provided that no compounds that can interfere withthe GC separation and electrochemical detection are present.1.6 This test method is written as a companion to PracticesD5287,D7165 and D7166.1.7 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.8 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:2D3609 Practice for Calibration Techniques Using Perme-ation TubesD4150 Terminology Relating to Gaseous FuelsD4626 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 DetectionD6968 Test Method for Simultaneous Measurement of Sul-fur Compounds and Minor Hydrocarbons in Natural Gasand Gaseous Fuels by Gas Chromatography and AtomicEmission Detection1This test method is under the jurisdiction ofASTM Committee D03 on GaseousFuels and is the direct responsibility of Subcommittee D03.12 on On-Line/At-LineAnalysis of Gaseous Fuels.Current edition approved June 1,2014.Published July 2014.Originally approvedin 2008.Last previous edition approved as D7493-08.DOI:10.1520/D7493-14.2For 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 D7165 Practice for Gas Chromatograph Based On-line/At-line Analysis for Sulfur Content of Gaseous FuelsD7166 Practice for Total Sulfur Analyzer Based On-line/At-line for Sulfur Content of Gaseous Fuels2.2 ISO Standards:3ISO 19739 Natural gas Determination of sulfur com-pounds by gas chromatography2.3 GPA Standard4GPA 2199 Determination-Determination of Specific SulfurCompounds by Capillary Gas Chromatography and SulfurChemiluminescence Detection3.Terminology3.1 Common terminology used in this method are cited inTerminology D4150.Sulfur compounds are commonly re-ferred by their initials(chemical or formula),for