质谱在钢铁行业过程控制中快速气体分析的应用

APPLICATIONSOFFASTGASANALYSISBYMASSSPECTROMETRYTOPROCESSCONTROLINTHEIRONANDSTEELINDUSTRY质谱在钢铁行业过程控制中快速气体分析的应用ROBERTWRIGHTTHERMOELECTRONCORPORATIONABSTRACT摘要THISPAPERDESCRIBESHOWFASTONLINEGASANALYSISBYMASSSPECTROMETRYISUSEDINTHEIRONANDSTEELINDUSTRYTOOPTIMISEVARIOUSPROCESSES,BASEDONACCURATEANDCOMPLETEANALYSISSTEELMAKINGGASANALYSISISUSEDFORBETTERPROCESSCONTROLANDENDPOINTDETERMINATIONTOEXPEDITEPROCESSTURNAROUNDIRONMAKINGGASANALYSISISUSEDTOOPERATEMOREEFFICIENTLYANDSAFELYCOKEOVENGASANALYSISISUSEDTOOPTIMISETHEGASCLEANINGWASTEGASESFROMVARIOUSPROCESSESAREUSEDASFUELGAS,WHICHNEEDSTOBECHARACTERISEDINTERMSOFCALORIFICVALUE,WOBBEINDEXANDSTOICHIOMETRICAIRREQUIREMENT,BUTTHESEGASESHAVEFASTCHANGINGCOMPOSITIONTHESEGASESAREALSOMIXEDTOMAKEMIXEDFUELGASFASTCOMPLETEGASANALYSISISREQUIREDTOOPTIMISETHEMIXINGOFTHESEGASESTOPROVIDEMIXEDGASOFCONSTANTCALORIFICVALUEORWOBBEINDEX本文描述在钢铁行业中如何采用质谱对气体进行准确、完整的快速在线气体分析以优化不同的过程。炼钢过程中的气体分析用于更好地控制过程，确定吹炼终点以加速吹炼周期。焦炉中的气体分析用于优化气体纯化。来源于不同过程中的废气用作燃气，通过热值，华比值和按化学计量组成所需空气量表征，这些气体组成变化很快。这些气体也被混合形成混合燃气。因此采用快速全面的气体分析来优化混合过程以提供稳定华比值的混合气体。INTRODUCTION介绍THETYPEOFMASSSPECTROMETERUSEDFORONLINEGASANALYSISISCOMMONLYREFERREDTOASAPROCESSMASSSPECTROMETER,ORPMSONEOFTHEWORLDSLARGESTSCIENTIFICINSTRUMENTMANUFACTURERS,THERMOELECTRONCORPORATION,HASBEENMANUFACTURINGPROCESSMASSSPECTROMETERSFOROVER20YEARSWITHMORETHAN1000SYSTEMSINSTALLEDWORLDWIDEONAWIDERANGEOFAPPLICATIONSINTHECHEMICALANDPETROCHEMICALINDUSTRIESANDINBIOTECHNOLOGYANDFORRESEARCHWATERISNOTCRITICAL,BUTOFTENTHEGASISDRIEDTHEMAINTENANCEREQUIREMENTSOFTHEPMSARENOTHIGH,NORMALUPTIMEIS998过程质谱仪对气体的取样条件和其他的过程气体分析仪相似。气体需要经过过滤和压力调节以提供足够流速（0210升/分）的干净样品气进入质谱仪，气体可含水，但通常样品气是干燥的。对质谱仪的维护要求并不高，正常的运行时间可达到998。THEMAINJUSTIFICATIONSFORINVESTINGINAPMSINSTRUMENTARETHEFOLLOWING对过程质谱投资只要理由如下ANALYSISRESPONSETIMEISVERYFASTASFASTAS15SECONDSFORANALYSISOF6COMPONENTS分析速度快（6个组分只需15秒）ITISMULTICOMPONENTALLCOMPONENTSOFINTERESTARETYPICALLYMEASUREDONASINGLEINSTRUMENT多组分测量所有待测的组分可在一台仪器上测量ITISMULTISTREAMMULTIPLESAMPLEGASESAREMEASUREDONTHESAMEINSTRUMENT多流路测量在同一台仪器上实现多路样品测量THEHIGHANALYTICALPERFORMANCEINTERMSOFSENSITIVITY,STABILITYANDLINEARITY具有高分析性能极高的灵敏度，稳定性和宽的线性范围THEREISADEFINITECOSTBENEFITININCORPORATINGCOMPOSITIONGASANALYSISORDERIVEDDATAINTOTHEPLANTCONTROLSTRATEGY气体组分分析和工厂数据控制产生的经济价值和益处远远超过投资HOWAMASSSPECTROMETERWORKS质谱仪原理THEREAREAFEWBASICELEMENTSTOAMASSSPECTROMETERANINLETTOINTRODUCETHESAMPLEGASINTOTHEVACUUMOFTHEMASSSPECTROMETER,ANIONSOURCETOCONVERTTHESAMPLEGASMOLECULESINTOPOSITIVELYCHARGEDIONS,AMASSFILTERTOSEPARATETHEIONSUSINGMAGNETICORELECTRICFIELDSANDADETECTORTHATQUANTIFIESTHEAMOUNTSOFIONSATDIFFERENTMASSESVERYIMPORTANTLY,THEREISAVACUUMCHAMBERWITHHIGHVACUUMPUMPSANDELECTRONICSTORUNTHEMASSSPECTROMETERMODERNINSTRUMENTSHAVEEMBEDDEDPROCESSORSTORUNTHEINSTRUMENTINACOMPLETELYSTANDALONEMANNER,SONOUSERINTERVENTIONISREQUIREDTOKEEPTHEINSTRUMENTANALYZINGANDCALIBRATEDOVERTHE12MONTHPERIODBETWEENSCHEDULEDMAINTENANCEOPERATIONS质谱仪的几个基本组成部分将样品引入质谱仪的进样系统，将气体分子转变为正离子的离子源，使用磁场或电场分离离子的质量分析器，对不同质量数离子定量的检测系统。拥有真空泵和电子装置的真空室质谱仪运行中重要组成部分。内置的处理器使仪器完全可以独立运行，无需人为干预便可实现12个月以上仪器自动分析和矫正。THEPMSINSTRUMENTSUPPLIEDBYTHERMOELECTRONFORTHEIRONANDSTEELINDUSTRYISTHEMODELVGPRIMABTHEVGPRIMABUSESDEFLECTIONINASECTORSHAPEDMAGNETICFIELDASTHEMASSFILTERTHEREISAVARIABLEELECTROMAGNETTOSELECTTHEDIFFERENTMASSIONSFORMEASUREMENTTHEMAGNETICFIELDISRAMPEDINVALUETOSTEPBETWEENTHECHARACTERISTICMASSES,EGFORMEASURINGH2,CO,N2,O2,ARANDCO2ITWILLFIRSTSETTHEMAGNETICFIELDTODETECTMASS2IONS,THENMASS12IONS,THENMASS14IONS,THENMASS32IONS,THENMASS40IONS,ANDTHENMASS44IONSTHESEMASSIONSCORRESPONDTOTHEGASESASSHOWNINTABLE1BELOWVGPRIMAB是热电公司为钢铁行业提供的过程质谱仪。VGPRIMAB采用扇形磁场质量分析器，使用可变磁场选择不同的待测离子。磁场强度根据特征质量作步进升高，如测量H2,CO,N2,O2,ARANDCO2，首先选择磁场检测质量数为2的离子，然后是质量数为12的离子，然后是14，32，40，44。这些离子在如下表1中列出。TABLE1MASSIONPEAKSCORRESPONDINGTOVARIOUSGASESMASSGASRESPONSIBLEFORSIGNALATTHISMASSDESCRIPTIONOFPOSITIVEIONPRODUCINGTHISSIGNAL2H2H212COCO212C14N214N32O216O240AR40AR44CO212C16O2ITSEENTHATMOSTOFTHEMASSPEAKSAREUNIQUETOONEGASTHEONLYEXCEPTIONISMASS12,WHICHRESULTSFROMTHECIONWHICHARISESFROMTHEIONISATIONOFBOTHCOANDCO2DURINGCALIBRATIONWHICHMEASURESTHEMAGNITUDEOFTHEPEAKHEIGHTFORAKNOWNCONCENTRATIONOFGAS,PURECO2ISUSEDFORDETERMININGTHERATIOOFTHEMASS12PEAKTOTHEMASS44PEAK,SOITISASIMPLECORRECTIONTOSUBTRACTTHECO2CONTRIBUTIONTOMASS12HOWEVER,THEREARELIMITATIONSTOTHEACCURACYOFTHISCORRECTIONANDARULEOFTHUMBISTHATTHEDETECTIONLIMITFORCOIS2OFTHECO2CONCENTRATION可以看出大多数质量峰和一种气体相对应。质量数为12的例外，由CO和CO2的离子化产生。在校正时，纯CO2用于确定质量峰为12和44的比例，因此只需减去CO2对质量数12的贡献。然而，这种校正方法的有一定的精度限制并且根据经验CO的检出限为CO2的2。AREPRESENTATIONOFAGASANALYSISMASSSPECTROMETERISSHOWNBELOWINFIGURE1FIGURE1SCHEMATICREPRESENTATIONOFAGASANALYSISMASSSPECTROMETERBENEFITOFMAGNETICSECTORMASSFILTER扇形磁场质量分析器的优点PROCESSMASSSPECTROMETERSTAKEMEASUREMENTSVERYQUICKLYBYJUMPINGTOEACHOFTHENOMINALMASSPOSITIONSTHEASSUMPTIONISTHATTOPOFTHEPEAKCOINCIDESWITHTHENOMINALMASSPOSITIONHOWEVERTHISMAYNOTBETHECASEIFTHEPEAKTOPISNARROWANDTHEMASSSCALEDRIFTSTHEADVANTAGEOFTHEVGPRIMAOVEROTHERPROCESSMASSSPECTROMETERDESIGNSISTHATITUSESASECTORSHAPEDMAGNETICFIELD,WHICHPRODUCESTRAPEZOIDALPEAKSHAPESWITHEXTENSIVEPEAKTOPSITISTHEREFOREVERYTOLERANTTODRIFTSINTHEMASSSCALE过程质谱仪通过跳到定义的质量位置实现快速测量。此假设基于峰顶的位置与所定义的质量位置相符合。然而，由于峰顶太窄或是质量漂移将会产生不同的结果。VGPRIMA优于其它过程质谱仪的设计在于其采用扇形磁场，产生的峰形为平顶的梯形峰，因此在质量范围内不易漂移。ANEXAMPLEAPPEARANCEOFAPEAKISSHOWNBELOWINFIGURE2图2为一质量峰峰形外观。FIGURE2PEAKSHAPEFROMMAGNETICSECTORMASSSPECTROMETEROVERVIEWOFIRONANDSTEELPROCESSES钢铁冶炼过程总述BELOW,INFIGURE3,ISSHOWNAREPRESENTATIONOFVARIOUSPROCESSESINTHEIRONANDSTEELWORKSWHICHUSEGASANALYSISASPARTOFTHEIRCONTROLASASIMPLEOVERVIEW,THEBLASTFURNACENEEDSCOKEFROMTHECOKEPLANTTOREDUCETHEIRONOREIRONOXIDETOIRONTHEIRONISCONVERTEDINTOSTEELINTHEBOFUSINGOXYGENTOREMOVEIMPURITIESSUCHASCARBONFURTHERREFININGMAYTAKEPLACEINPROCESSESSUCHASAOD,VODORRHCONTINUOUSCASTINGCONVERTSTHESTEELINTOBILLETS,BLOOMSANDSLABSREHEATFURNACESTHENMELTTHISSTEELFORMAKINGITINTOTHEVARIOUSPRODUCTSSUCHASSHEETS,BARS,RODS,COILSETCANOTHERROUTETOSTEELISFROMDRITOMAKETHEIRONFROMIRONOREANDNATURALGASTHEPRODUCTISTHENUSEDINANEAFTOMAKESTEELHOWEVER,THEMAINMATERIALUSEDINTHEEAFISSCRAPSTEEL如下图三为在钢铁冶炼过程中气体分析作为过程控制的系统图。焦炉厂中生成的焦炭在高炉中还原铁矿石（铁的氧化物）成铁。在氧气顶吹转炉中，通过氧除去碳等杂质将铁转为钢。在AOD,VOD或RH过程中进一步精炼。连铸将钢转变为钢柸，初轧抷和厚板。然后再热炉将钢铁融化炼成不同的产品如钢片，钢条，钢棒和钢圈等。另外一种方法是直接还原，从铁矿中炼铁和天燃气。产物被用于电弧炉中炼钢。然而，在电弧炉法中主要的原料是废钢。FIGURE3PROCESSESINTHEIRONANDSTEELWORKSWHICHUSEGASANALYSISCOKEOVEN焦炉INACOKEOVENPLANT,ARAWGASOFHIGHCALORIFICVALUEISPRODUCEDASABYPRODUCTFROMTHEPYROLYSISOFCOALTHECOKEPRODUCTBEINGUSEDINABLASTFURNACEFORIRONPRODUCTIONAFTERPURIFICATION,COKEOVENGASISUSEDASFUELBYOTHERPROCESSESINTHEIRONANDSTEELWORKSAPURIFICATIONPLANTISNECESSARYTOREMOVEPROBLEMATICNAPHTHALENEBLOCKAGES,ANDENVIRONMENTALLYHARMFULH2S,NH3,BENZENECOMPONENTSONLINEMONITORINGOFH2SANDO2AREOFTENWELLESTABLISHEDONCOKEOVENPLANTSHOWEVER,MEASUREMENTOFNH3,NAPHTHALENEANDBENZENETRADITIONALLYWEREPERFORMEDBYWETCHEMICALMETHODSONADAILYSPOTSAMPLEBASISHOWEVER,MORERECENTLYMASSSPECTROMETRYHASBEENAPPLIEDTOEXTENDTHERANGEOFCOMPONENTSINPURIFIEDCOKEOVENGASBEINGSUBJECTEDTOONLINEMONITORINGITHASBEENFOUNDTHATONLINEMONITORINGALLOWSOPTIMIZATIONOFTHESCRUBBERPLANTSREFS1,2ADDITIONALLY,THEMASSSPECTROMETRICANALYSISOFALLTHECOMPONENTSISEXPANDEDTODERIVETHECOMBUSTIONPROPERTIESOFTHEGASTHISISIMPORTANTBECAUSETHISGASISUSEDASFUELBYVARIOUSOTHERPROCESSESASWELLASFORHEATINGTHECOKEOVENBATTERIESTHEMSELVESTHESEPROPERTIESINCLUDECALORIFICVALUE,DENSITY,SPECIFICGRAVITY,WOBBEINDEXANDSTOICHIOMETRICAIRREQUIREMENTSUCHCALCULATIONSENABLETHEMOREEFFICIENTUSEOFFUELANDTHESAVINGSCANBECONSIDERABLETYPICALCOMPOSITIONOFCOKEOVENGASMEASUREDBYPMSISSHOWNBELOWINTABLE2在焦炉厂中，裂解煤的副产物为高热值的原料气体（焦炭产物在高炉中用于还原铁）。经纯化后，焦炉气体在其他钢铁冶炼过程中用作燃料。净化厂是必需的以除去干扰物（萘阻塞）和环境污染物（H2S,NH3,苯）。在焦炉厂中通常能很好地监测H2S和O2。然而，对氨，萘和苯的测量采用传统的化学湿法只能每天测量一个样品点。最近质谱用于在线监测焦炉气体纯化厂扩大了气体组分的测量范围。研究发现在线监测能优化气体纯化过程。而且，质谱对所有气体组分的分析扩展为推导气体的燃烧特性。这点十分重要，因为气体不仅在其他过程中用作燃料，同时也用作加热焦炉本身。这些特性包括热值，密度，比重，华比值，按化学计量组成所需的空气量。对气体的推导计算能更有效地利用燃气并且节约大量成本。表二所示为常测的焦炉中的气体组分。TABLE2TYPICALCOMPOSITIONOFCOKEOVENGASANDPRECISIONOBTAINEDBYPMSRANGEOFSAMPLEGASMOLECONCENTRATIONPRECISIONMOLEH26264008CH42225005NH30013130001H2O2225001HCN0071012002CO56005N21527005C2H4185001C2H6085001O2010150002H2S0230490001C3H6010001CO21150005C6H6/C7H8/C8H100170860001C10H800007002500002BLASTFURNACE高炉INABLASTFURNACE,COKEISUSEDTOREDUCETHEOREIRONOXIDETOIRONLARGEQUANTITIESOFGAS,TOPGAS,AREFORMEDATTHETOPOFTHEBLASTFURNACEASARESULTOFTHEREDUCTIONOFIRONOREANDTHECOMBUSTIONOFINJECTEDCOALBYINJECTEDBLASTAIR在高炉中，焦炭将铁矿石（铁的氧化物）还原为铁。在还原铁的过程和由鼓风注入的煤的燃烧过程中，高炉顶部生成大量的气体。GASANALYSISISUSEDTOOPTIMIZETHEBLASTFURNACEPROCESS,INCLUDINGREDUCINGTHECONSUMPTIONRATEOFCOKEANDCONTROLLINGTHETEMPERATURESINSIDETHEFURNACEREF4ANALYSISOFHYDROGENISVERYIMPORTANTFOREARLYDETECTIONOFCOOLINGWATERLEAKSTHATMAYRESULTINCONSIDERABLEDAMAGEANDEVENEXPLOSIONSREF4TYPICALCOMPOSITIONOFBLASTFURNACEGASMEASUREDBYPMSISSHOWNBELOWINTABLE3气体分析用于优化高炉过程，包括还原过程中焦炭的消耗速度和炉内的温度控制。冷却水的泄漏会导致严重的损坏甚至爆炸，因此对氢气的分析尤为重要。图三为由过程质谱测量的高炉中的组分。TABLE3TYPICALCOMPOSITIONOFBLASTFURNACEANDPRECISIONOBTAINEDBYPMSCONCENTRATIONMOLEPRECISIONMOLEH240005CO24003N246002O2FECOTHECOKEISALSOUSEDASTHEFUELFORTHEBLASTFURNACEPROCESS焦炭也被用作是高炉过程的燃料。ANALTERNATIVEAPPROACHINIRONPRODUCTION,WHICHDOESNOTREQUIRECOKE,ISTHEPROCESSKNOWNASDIRECTREDUCTIONINTHISPROCESSTHEIRONOREISREDUCEDTOIRONBYCARBONMONOXIDEANDHYDROGEN炼钢的另一种方法是直接还原，这个过程不需要焦碳，铁矿石被CO和H2还原。3FE2O39CO6FE9CO23FE2O39H26FE9H2OTHEREDUCINGGASES,IECOANDH2AREGENERATEDBYREACTIONOFNATURALGASMETHANEWITHTHEBYPRODUCTSOFTHEDIRECTREDUCTIONPROCESS还原气体如CO和H2，由天燃气（CH4）和直接还原法的反应的副产品生成。CH4CO22CO2H2CH4H2OCO3H2THESEGASREACTIONSTAKEPLACEINAREACTORREFERREDTOASAREFORMER这些气体的反应在反应器中进行。THENATURALGASISALSOUSEDASTHEFUELFORTHEPROCESSINSOMEDIRECTREDUCTIONPLANTS,HIGHERHYDROCARBONSOREVENOILORCOALAREUSEDINSTEADOFNATURALGAS,BUTTHEPRINCIPLESARETHESAME天燃气在过程中也被用作燃料。一些直接还原钢铁厂采用高烃甚至油或煤代替天燃气，基本原理都是相同的。THESCARCITYOFSUITABLECOKEFORUSEINTHEBLASTFURNACEANDTHECHEAPNESSOFNATURALGASOROTHERFUELSCANFAVOURTHEADOPTIONOFTHEDIRECTREDUCTIONPROCESSFORIRONPRODUCTIONINCERTAINPARTSOFTHEWORLDANDAPPROXIMATELYONEHUNDREDDIRECTREDUCTIONSTEELPLANTSHAVEBEENBUILTOVERTHELASTFORTYYEARS用于高炉中的焦炭的稀缺和天燃气及其他燃料低廉的价格使得许多炼铁厂采用直接还原法，在过去的四十多年里有近百家炼铁厂采用此方法。FROMACONSIDERATIONOFTHEABOVEIMPORTANTREACTIONSOCCURRINGINADIRECTREDUCTIONPROCESS,ITCANBEREADILYAPPRECIATEDTHATPROCESSCONTROLREQUIRESACCURATEONLINEMONITORINGOFGASSTREAMSCONTAININGH2,CH4,COANDCO2MASSSPECTROMETRICGASPROVIDESTHEBESTCOMBINATIONOFSPEEDANDACCURACYCOMPAREDWITHALTERNATIVEMETHODSOFGASANALYSISSUCHASINFRAREDANALYZERSORGASCHROMATOGRAPHSTHEREAREACTUALLYATLEAST9SAMPLESTREAMSWHOSECOMPOSITIONNEEDSTOBEMONITOREDINORDERTOCONTROLADRIPLANTTHEWORLDSLARGESTLICENSOROFDRIPROCESS,MIDREXTECHNOLOGIES,INCSPECIFICALLYRECOMMENDTHATMASSSPECTROMETRYBEUSEDFORTHEGASANALYSISREF6TYPICALGASSAMPLES,WHICHAREMEASUREDBYPMSONADRIPLANT,ARESHOWNBELOWINTABLE4从以上直接还原炼铁过程中的重要反应可看出，此过程需要精确在线监测气体流路H2,CH4,CO和CO2。质谱仪可提供快速，精确的气体分析，同时取代其他分析方法如红外，气相色谱。控制DRI过程实际需要至少监测9个样品流路的气体组分。世界上最大的DRI过程认证颁发者MIDEREX公司特别推荐质谱用于气体分析。表四列出了常规气体分析样品。TABLE4TYPICALDRIGASANALYZEDBYPMSSTREAMNUMBER123456789DRYCOMPOSISTIONSUNITSPROCESSGASREFORMEDGASBUSTLEGASCOOLINGGASFEEDGASREFORMERFLUEGASRECUPERATORFLUEGASSEALGASNATURALGASCOVOL27037236727219CO2VOL20125250916617711817814H2VOL488576568566395003002002H2OVOLCH4VOL302033273199919N2VOL1106061220980379880203O2VOL198420C2H6VOL01010842C3H8VOL0020020315C4H10VOL001010107H2SVOLPPM5040402060100EAF电弧炉炼钢THEELECTRICARCFURNACECONVERTSSCRAPMETALINTOSTEELUSINGELECTRICALENERGYANDCHEMICALENERGYITUSESOXYFUELBURNERSANDOXYGENLANCESTHEAMOUNTOFOXYGENINTRODUCEDBYTHEOXYGENLANCESISIMPORTANTFORACHIEVINGCOMBUSTIONOFCOTOCO2TERMEDPOSTCOMBUSTIONTHISISIMPORTANTBECAUSECO,WHICHLEAVESTHEFURNACENONOXIDIZED,ISLOSTTOTHEVENTWHEREITWILLTHENBECOMBUSTEDBUTTHEHEATISEFFECTIVELYLOSTTHEGASEVOLVEDFROMTHEFURNACECONSISTSOFH2,CH4,CO,N2,O2,AR,CO2ANDH2OTHEELECTRICARCPROCESSHEATTYPICALLYTAKES12HOURS电弧炉利用电能和化学能将废料转变为钢。由氧枪吹入的氧量对于将CO燃烧为CO2地控制十分关键。这是因为未被氧化的CO在排气口燃烧损失了热能。电弧炉的氧化过程时间为12小时，从炉内排出的气体包含H2,CH4,CO,N2,O2,AR,CO2和H2O。THEMAINOBJECTIVEOFTHEGASANALYSISISTOPROVIDEDATAFORCONTROLOFPOSTCOMBUSTION,TOMINIMISELOSSOFCOFROMTHEFURNACETHISREQUIRESACCURATECO2,COMONITORINGTOCONFERSIGNIFICANTENERGYSAVINGS气体分析的主要目的是为氧化终点控制提供数据，以最小化CO的损失因此需精确监测CO2和CO。RELIABLEANALYTICALDATAONTHEFORMATIONOFH2ISIMPORTANTFORHIGHLIGHTINGWATERINGRESSFROMCOOLINGWATER,WHICHCANCAUSESEVEREENERGYLOSSLATENTHEATANDHEATCAPACITYOFWATER对因冷却水进入炉内形成H2的监测也十分重要，因其可造成不可估量的能源损失。FUELGAS燃气REHEATFURNACESAREUSEDTOMELTTHESTEELTOFABRICATETHESTEELINTODIFFERENTPRODUCTSTEELSHAPESSUCHASSHEETS,BARS,RODS,COILS,PLATES,PIPES,TUBESANDOTHERSHAPESINVARIOUSMILLSTHEFUELGASFORREHEATFURNACESISOFTENAMIXTUREOFDIFFERENTGASES,SUCHASCOKEOVENGAS,BLASTFURNACEGASANDBOFGASFASTCOMPLETEGASANALYSISISREQUIREDTOOPTIMISETHEMIXINGOFTHESEGASESBYAGASMIXINGSTATIONTOPROVIDEMIXEDGASOFCONSTANTCALORIFICVALUEORWOBBEINDEXEVENWHENTHEGASESARENOTMIXED,THERECANSTILLBECONSIDERABLEVARIATIONINCOMPOSITIONANDTHEREFORECOMBUSTIONPROPERTIES,SUCHASCALORIFICVALUE,DENSITY,SPECIFICGRAVITY,WOBBEINDEXANDSTOICHIOMETRICAIRREQUIREMENTINORDERTOMAINTAINCONSTANTBURNERPERFORMANCEANDMAXIMISEEFFICIENCYTHESECOMBUSTIONPROPERTIESNEEDTOBEACCURATELYMONITOREDTHISISWHEREPMSHASVERYSIGNIFICANTBENEFITSOVEROTHERMETHODSOFMONITORINGTHEANALYSISISCOMPREHENSIVEEVERYTHINGISMEASUREDWHILSTALSOBEINGFASTTHELATTERPOINTISIMPORTANTWHERETHEGASCOMPOSITIONCANCHANGERAPIDLYDISCUSSION讨论ALTERNATIVETECHNIQUESFORGASANALYSISAREAVAILABLEGASCHROMATOGRAPHYGCISAWELLESTABLISHED,RELIABLEANDACCURATEMETHODOFONLINEGASANALYSISTHEONLYMAJORDISADVANTAGEISTHATITISVERYSLOWANALYSESTYPICALLYTAKEATLEAST5MINUTESWHICHISTOOSLOWFORPROCESSCONTROLINTHEIRONANDSTEELINDUSTRYALESSERDISADVANTAGEOFGCISTHATSOMECOMPONENTSCANNOTBESEPARATEDEGARGONANDOXYGENANOTHERTECHNIQUEISINFRAREDIRTHISTECHNIQUEISALSOSLOWERTHANPMSANDANOTHERDISADVANTAGEISTHATITCANONLYMEASURECOMPONENTSWITH2ORMOREDISSIMILARATOMSIEMOLECULESWITHADIPOLEMOMENT,SUCHASCOANDCO2THEREFORETHEANALYSISISLIMITEDTHERMALCONDUCTIVITYCANBEUSEDTOANALYSEFORHYDROGEN,BUTTHEACCURACYANDLINEARITYISINFERIORTOTHATOFPMS,DUETOTHEASSUMPTIONSTHATAREMADEABOUTTHETHERMALCONDUCTIVITYOFTHEBALANCEGASANEMERGINGTECHNIQUEUSESLASERANALYSISSUCHANINSTRUMENTISACTUALLYINSTALLEDINLINEANDHASINBUILTCORRECTIONFORLIGHTATTENUATIONBYDUSTPARTICLESTHISTECHNIQUETHEREFOREAVOIDSTHENEEDFORSAMPLECONDITIONINGANDANANALYZERSHELTERTHATCANCOSTASMUCHASTHEPMSITSELFHOWEVER,THISLASERANALYSISISARELATIVELYEXPENSIVETECHNIQUETOUSEFORTYPICALLYONLYONEORTWOCOMPONENTSANDTHERANGEOFCOMPONENTSTHATCANBEMEASUREDISALSOSEVERELYLIMITEDCERTAINOTHERDISCRETEANALYZERSARESOMETIMESUSEDINTHEIRONANDSTEELINDUSTRY,SUCHASPARAMAGNETICSENSORFORO2ANDLEADACETATETAPEFORH2SANDPROVIDEEXCELLENTSENSITIVITYANDSTABILITYFORTHESESPECIFICSPECIES其他的分析方法也用于气体分析。气相色谱是用于在线的可靠精确的气体分析方法，其主要的缺点是分析速度慢通常至少需要5分钟，而这对钢铁行业的过程控制来说显然太慢。另一个缺点是有些组分无法分析如氩和氧。另一种技术是红外。这种技术分析速度也比过程质谱慢，同时只能分析包含2个或更多原子的气体组分（即有偶极矩的分子）如CO和CO2。因此，这种分析方法也有局限。热导方法用于分析氢气，但是精度和线性劣于过程质谱。最近出现激光法用于气体分析，采用内嵌的安装和通过微粒对光的衰减进行内置的校正，因此不需样品预处理和价格和分析小屋。但是，激光法分析通常只能测量一两种组分，而且测量的组分范围也十分有局限，因此是一种相对比较昂贵的技术。其他一些单点分析仪也用在钢铁行业，如氧气分析仪和测硫化氢的醋酸铅纸带用于对特定的样品提供高灵敏度和可靠性的分析。SOTHEMAINADVANTAGESOFPMSARETHESPEEDOFANALYSISANDTHERANGEOFCOMPONENTSTHATCANBEMEASUREDSUCHTHATTYPICALLYONLYONEINSTRUMENTISREQUIREDTOMEASUREALLTHEGASCOMPONENTSOFINTERESTINAPROCESSSOMEUSERSOFPMSINTHEIRONANDSTEELINDUSTRYHAVEFOUNDTHATASWELLASENABLINGPROCESSCONTROLBASEDONGASCOMPOSITIONANALYSIS,PMSALSOOFFERSFURTHERINSIGHTSINTOTHEPROC