GPA-2261-13天然气组分分析-GC法

AnalysisforNaturalGasandSimilarGaseousMixturesbyGasChromatographyAdoptedasTentativeStandard,1961RevisedandAdoptedasaStandard,1964Revised1972,1986,1989,1990,1995,1999,2000and2013GasProcessorsAssociation6526East60thStreetTulsa,Oklahoma74145GPAStandard2261-13DISCLAIMERGPApublicationsnecessarilyaddressproblemsofageneralnatureandmaybeusedbyanyonedesiringtodoso.EveryefforthasbeenmadebyGPAtoassureaccuracyandreliabilityoftheinformationcontainedinitspublications.Withrespecttoparticularcircumstances,local,state,andfederallawsandregulationsshouldbereviewed.ItisnottheintentofGPAtoassumethedutiesofemployers,manufacturers,orsupplierstowarnandproperlytrainemployees,orothersexposed,concerninghealthandsafetyrisksorprecautions.GPAmakesnorepresentation,warranty,orguaranteeinconnectionwiththispublicationandherebyexpresslydisclaimsanyliabilityorresponsibilityforlossordamageresultingfromitsuseorfortheviolationofanyfederal,state,ormunicipalregulationwithwhichthispublicationmayconflict,orforanyinfringementoflettersofpatentregardingapparatus,equipment,ormethodsocovered.FOREWARDGPA2261providesthegasprocessingindustryamethodfordeterminingthechemicalcompositionofnaturalgasandsimilargaseousmixturesusingaGasChromatograph(GC).Theprecisionstatementscontainedinthisstandardarebasedonthestatisticalanalysisofround-robinlaboratorydataobtainedbySectionB.ThisstandardwasdevelopedbythecooperativeeffortsofmanyindividualsfromindustryunderthesponsorshipofGPASectionB,AnalysisandTestMethods.Throughoutthispublication,thelatestappropriateGPAStandardsarereferenced“Copyright©2013byGasProcessorsAssociation.Allrightsreserved.NopartofthisReportmaybereproducedwithoutthewrittenconsentoftheGasProcessorsAssociation.”11.SCOPE1.1ThisstandardcoversthedeterminationofthechemicalcompositionofnaturalgasandsimilargaseousmixtureswithintherangeslistedinTable1,usingaGasChromatograph(GC).ThethreecolumnsrepresenttheoriginalTable1,butseparatethevaluestothreedistinctgroups.Thefirstgroupisconcentrationslowerthanthedataobtainedfromtheround-robinproject(RR-188).Thesecondgroupisconcentrationsusedintheround-robinproject(RR-188).Theequationslistedintheprecisionstatementinthisstandardcovertherangelistedinthemiddlecolumn,afteroutlierswereremoved.Thethirdgroupisconcentrationshigherthanthedataobtainedfromtheround-robinproject(RR-188).TheprecisionstatementinthisstandardutilizesequationsderivedfromaregressionofthedatainRR-188andisdetailedinGPATP-31.TheprecisionstatementcriterionappliesonlytovalueslistedinSection10,Table6.1.2Componentssometimesassociatedwithnaturalgases,i.e.,helium,hydrogensulfide,water,carbonmonoxide,hydrogenandothercompoundsareexcludedfromthemainbodyofthemethod.Thesecomponentsmaybedeterminedandmadeapartofthecompletecompositionaldata.RefertoAppendixA.TableIRangesofNaturalGasComponentsCoveredComponentLowerRegionRoundRobinHigherRegionNitrogen0.01-0.10.1-3030CarbonDioxide0.01-0.10.1-3030Methane0.01-4040-100N/AEthane0.01-0.10.1-1010Propane0.01-0.10.1-1010Isobutane0.01-0.250.25-44n-Butane0.01-0.250.25-44Isopentane0.01-0.120.12-1.51.5n-Pentane0.01-0.120.12-1.51.5*HexanesPlus0.01-0.10.1-1.51.5*HeptanesPlus0.01-0.10.1-1.51.5*Datafromround–robinwasonlyobtainedforHexanesPlusTableNote:UncertaintyintheLowerregioncaneasilybetentimesgreaterandinthehigherregiontwotothreetimesgreaterthanthecentercolumn.NOTE1–ComponentsnotlistedinTable1maybedeterminedbyproceduresoutlinedinAppendixAorotherapplicableanalyticalprocedures.RefertoAppendixA.2.SUMMARYOFMETHOD2.1Componentstobedeterminedinagaseoussamplearephysicallyseparatedbygaschromatographyandcomparedtocalibrationdataobtainedunderidenticaloperatingconditions.Afixedvolumeofsampleinthegaseousphaseisisolatedinasuitableinletsamplesystemandenteredontothecolumn.2.2Thefullrangeanalysisofagaseoussamplemayrequiremultiplerunstoproperlydetermineallcomponentsofinterest.Theprimaryrunisonapartitioncolumntodetermineair,methane,carbondioxide,ethaneandheavierhydrocarbons.Whenoxygen/argoncontentiscriticalintheunknownsample,orissuspectedasacontaminant,asecondaryrunshouldbemadetodetermineoxygen/argonandnitrogenintheairpeakonthepartitioncolumn.Whencarbondioxidecontentintheunknownsampledoesnotfallwithinthecalibratedrangeonthepartitioncolumn,asecondaryrunshouldbemadetodeterminecarbondioxidecontent.Whenheliumand/orhydrogencontentarecriticalintheunknownsample,asecondaryrunshouldbemadetodetermineheliumand/orhydrogen.2.2.1Theseanalysesareindependentandmaybemadeinanyorder,ormaybemadeseparatelytoobtainlessthanthefullrangeanalysis.TheconfigurationcanconsistofasingleormultipleGC’stoaccomplishthis.RefertoAppendixA.2.3Responsefactorsorresponsecurvesderivedfromcalibrationdataareessentialtoaccuratelydeterminethecompositionofanunknownsample.ThereferencestandardblendandtheunknownsamplesmustberunusingidenticalGCoperatingconditions.3.APPARATUS3.1Chromatograph-AnyGasChromatographmaybeusedaslongasthespecificationsforrepeatabilityandreproducibilitystatedinSection10withintheround-robintestcomponentrangeslistedinTable1aremetorexceeded.Theequipmentdescribedinthissectionhasbeenpro