ASTM_D_8488_-_22.pdf

Designation:D848822Standard Test Method forDetermination of Hydrogen Sulfide(H2S)in Natural Gas byTunable Diode Laser Spectroscopy(TDLAS)1This standard is issued under the fixed designation D8488;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 online determination ofhydrogen sulfide(H2S)in natural gas using tunable diode laserabsorption spectroscopy(TDLAS)analyzers also known as a“TDL analyzers.”The particular wavelength for H2S measure-ment varies by manufacturer,typically between 1000 and10 000 nm with an individual laser having a tunable range ofless than 10 nm.The H2S concentration ranges can be any-where from 0-5 ppm(v)to 0-90%by volume.1.2 UnitsThe values stated in SI units are to be regardedas the standard.No other units of measurement are included inthis standard.TDLAS analyzers inherently output concentra-tions in unitless molar ratios such as ppm(v).NOTE1Weight-per-volume units such as milligrams or grains of H2Sper cubic foot or cubic meter can be derived from ppm(v)at“standardconditions”or standard temperature and pressure.1.3 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,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.4 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:2D1945 Test Method for Analysis of Natural Gas by GasChromatographyD4150 Terminology Relating to Gaseous FuelsD5503 Practice for Natural Gas Sample-Handling and Con-ditioning Systems for Pipeline Instrumentation(With-drawn 2017)3D5504 Test Method for Determination of Sulfur Compoundsin Natural Gas and Gaseous Fuels by Gas Chromatogra-phy and ChemiluminescenceD6228 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 DetectionD7551 Test Method for Determination of Total VolatileSulfur in Gaseous Hydrocarbons and Liquefied PetroleumGases and Natural Gas by Ultraviolet FluorescenceD7833 Test Method for Determination of Hydrocarbons andNon-Hydrocarbon Gases in Gaseous Mixtures by GasChromatography3.Terminology3.1 DefinitionsFor definitions of general terms used inD03 Gaseous Fuels standards,refer to Terminology D4150.3.2 Definitions of Terms Specific to This Standard:3.2.1 absorption spectroscopy,nrefers to spectroscopictechniques that measure the absorption of electromagneticradiation as a function of frequency or wavelength because ofits interaction with a sample.3.2.2 adsorption,nadhesion of molecules to a solid sur-face forming a molecular or atomic film.3.2.3 chemometrics,nfield of science relating measure-ments made on a chemical system or process to the state of thesystem via application of mathematical or statistical methods.3.2.4 desorption,nphenomenon whereby a substance isreleased from a surface(the opposite of adsorption).3.2.5 heat trace,nribbon-shaped tape that uses electricalresistance or tubing carrying steam to generate heat.1This 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 Nov.1,2022.Published November 2022.DOI:10.1520/D8488-22.2For 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.3The last approved version of this historical standard is referenced onwww.astm.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.13.2.5.1 DiscussionHeat trace tape is attached to sampletubing and other sample-conditioning components to avoidcondensation and stabilize the temperature of the wettedcomponents and the gas stre