CNG三元催化剂

INTRODUCTIONTOCNGFUELAugust2007Dr.JonathanCooperPrincipalScientistConfidentialConfidentialCNGCNGConfidentialCNGFUELPROPERTIESEMISSIONSCHEMISTRYConfidentialEMISSIONSCHEMISTRYNaturalgasisanexcellentfuelsourceforurbantransportationNaturalgasisanexcellentfuelsourceforurbantransportationandismainlycomposedofmethane(85%)–Perunitofenergy,naturalgascontainslesscarbonthananyotherfossilfuel,andthusproduceslowerCO2emission.¾2025%reductioninglobalwarmingindexrelativetogasoline¾20-25%reductioninglobalwarmingindexrelativetogasoline•ExhaustemissionsfromatypicalNGVaremuchlowerthanthoseExhaustemissionsfromatypicalNGVaremuchlowerthanthosefromgasoline-poweredvehicles.¾Non-methaneorganicgas(NMOG)by87%¾COby70%¾NOxby87%¾COby20%¾CO2by20%CONFIDENTIALConfidentialCNGFUELPROPERTIESCOMBUSTIONCHARACTERISTICSConfidentialCOMBUSTIONCHARACTERISTICS•Veryhighoctanenumber(RON=130),highknockresistance,capabilityofoperatingatλ=1inallengineoperationscapabilityofoperatingatλ=1inallengineoperations•NaturalgasformshomogeneousmixturewithairsogivesgoodNaturalgasformshomogeneousmixturewithairsogivesgoodAir-Fueldistributionbetweencylinders¾Advantageousforcoldstarts,noenrichmentneeded¾CleancombustionNtlbtidiifitldhdthi•Naturalgascombustionproducesnosignificantaldehydesorotherairtoxins•Particulatematterisreducedbyasmuchas95%y¾Nearcompletereductioninemittedtoxic,carcinogenicandozone-tihttittdllfttpromotingexhaustconstituentsandlowsulfurcontentCONFIDENTIALConfidentialCNGFUELPROPERTIESSAFETYConfidentialSAFETY•Ingasolinevehicles,evaporativeandfuelingemissionsaccountgpgforatleast50%ofavehicle'stotalhydrocarbonemissions-dedicatedNGVsproducelittleornoevaporativeemissions•Naturalgasisnottoxicorcorrosiveandwillnotcontaminategroundwaterg•Naturalgas,unlikegasoline,islighterthanairandthereforediititththithtfidtdissipatesintotheatmosphereintheeventofanaccident•Theflammabilityrangeofnaturalgasisbetweenabout515%•Theflammabilityrangeofnaturalgasisbetweenabout5-15%gastoair.Ifthereisnotenoughortoomuchairnaturalgaswillnotignite.CONFIDENTIALConfidentialCNGFUELPROPERTIESSAFETYConfidentialSAFETY•ThefuelstoragecylindersusedinNGVsaremuchstrongerthangyggasolinefueltanks-thefuelisstoredathighpressure(200bar)andthecylindersaredesignedtowithstandsevereabuse.Theyaresubjectedtoanumberoftestssuchasextremesofheatandaresubjectedtoanumberoftests,suchasextremesofheatandpressure,gunfireandcollisions.CONFIDENTIAL“Onlyanarmour-piercingbulletshotfromaNATO-styleassaultriflecanpenetratethemetalcylinder.”ConfidentialCNGCHEMISTRYCHALLENGESConfidential•ThemethanemoleculeisstabletheleastreactiveHCandis•Themethanemoleculeisstable,theleastreactiveHCandisthereforemoredifficulttooxidiseacrossacatalyst¾C-Hbondsarestrong(435kJ/mol)¾Symmetricalmolecule,nofunctionalgroups,magneticmomentorpolardistributionstofacilitatechemicalattacks¾Higheractivationenergyisneededtoinitiatelightoff¾Higheractivationenergyisneededtoinitiatelight-off•BecauseCOproductionislowerthaningasolineenginesNOBecauseCOproductionislowerthaningasolineenginesNOconversioncanalsobeproblematic¾CO+NOÆCO2+½N2•Methaneisastronggreenhousegas;itsglobalwarmingpotentialis21timesthatofCOpotentialis21timesthatofCO2CONFIDENTIALConfidentialSCATLIGHTOFFJM604/120/0:11:1Ovenaged4hrs1000oCinairConfidentialJM604/120/0:11:1-Ovenaged4hrs1000oCinairMETHANEMODEGASOLINEMODE80901008090100)METHANEMODEGASOLINEMODE4050607080sionEfficiency(%)CO%4050607080sionEfficiency(%)010203040ConversHC%NOx%010203040Convers100150200250300350400450Temperature(癈)100150200250300350400450Temperature(癈)HCT50–229oCHCT75–248oCHCT50–295oCHCT75–323oC60-70ºCdifferenceHCT75248CHCT90–267oCHCT75323CHCT90–368oCInCNGmodehighertemperaturesareneededtoinitiatelightoffgpgConfidentialSCAT450oCLAMBDASCANJM604/120/0:11:1Ovenaged4hrs1000oCinairConfidentialJM604/120/0:11:1-Ovenaged4hrs1000oCinairMETHANEMODEGASOLINEMODEMETHANEMODEGASOLINEMODE100110100110708090ionEfficiency(%)CO%HC%NOx%708090ionEfficiency(%)405060Convers405060Conversi400.970.980.991.001.011.021.03Lambda400.970.980.991.001.011.021.03LambdaInCNGmodecatalystsrequiretighterlambdawindowofoperationInCNGmodecatalystsrequiretighterlambdawindowofoperationandlowerperturbationfrequenciesConfidentialCNGCHEMISTRYCHALLENGESEUROPEANMARKETConfidentialEUROPEANMARKET•EuropeanmarketforCNGvehiclesislimitedduetothepoorproliferationofnaturalgasrefuellingstationsbutCNGmarketisgrowingofnaturalgasrefuellingstationsbutCNGmarketisgrowing–CNGpassengervehiclesarenowstartingtoreceivetaxincentives–CNGfuelpricesarelowerthanmanyotherfuelsduetolowertaxationpy–Preferentialaccessofcitycentrestogreenvehicles•StageVlegislationfavoursCNGtosomeextent–NMHC0.068g/kmTHC01/k–THC0.1g/km•FederallegislationexcludesmethanebecauseofitsunreactivenatureFederallegislationexcludesmethanebecauseofitsunreactivenaturetowardsphotochemicalsmoggenerationreactions–EPAarelookingatnon-CO2greenhousegasesinthefightagainstclimatechangeCONFIDENTIALConfidentialEFFECTOFOXYGENONACTIVESITEConfidential•OxygenabsorptiononPdisfastandirreversiblebelow400oC,whilstmethaneabsorptionisaslowandactivatedprocessOff–Oxyge