工业催化原理-英文课件Chapter1

CatalysisandIt’sReactionKineticsByXuzhude&JiangXianzhengDepartmentofChemistryZhejiangUniversityChapter1IntroductionandBasicConception§1.1SignificanceofcatalysistomodernchemicalindustrySomeconceptscatalysiscatalystcatalyticactivitycatalyzedreactionTheimportanceofcatalystThefirstcatalyticprocessofindustrialsignificancewasdevelopedasearlyas1875.ItisPlatinum(Pt)catalyzedoxidationofSO2toSO3whichwasthenconvertedtosulfuricacidH2SO4TherearenosuchprogressesofmodernchemicalindustrywithoutcatalysisMorethaneightypercents(80%)ofchemicalengineeringprocessesinvolvecatalysisSeveralimportantappliedfieldsofcatalysisSynthesisofAmmonia--atypicalillustrationforthedevelopmentofcatalystFe-Al2O3-K2ON2+3H22NH3thisreactionalmostcannotbeobservedattheatmospherepressureandroomtemperatureeventhroughitsGisnegative.BASFfirstachievedtheindustrialprocessofammoniasynthesisin1910,andwontheNobelprizeof1932.SeveralimportantappliedfieldsofcatalysisPetroleumrefiningcatalyzedcrackingofcrudeoiland/orheavyoiltoenrichthelightoilcomponents.Hydrocarbonwithlargermolecularweightcrackstosmallermolecules.SiO2-Al2O3,ZSM-5zeoliteReforming:convertingalkylhydrocarbontoaromatichydrocarbonPlatinumPtSeveralimportantappliedfieldsofcatalysisPolymer:Synthesizedfiber,robber,andplasticpolymerizationofolefin(ester,acrylonitrile......)Zeagler-Nattatypecatalyst-TiCl4/AlEt3ProductionofprimaryorganicchemicalsaminoxidationofpropenetoacrylonitrileCH2=CHCH3+NH3+1/2O2CH2=CHCN+3H2OP-Mo-Bi,multi-componentcatalystSeveralimportantappliedfieldsofcatalysisProductionofprimaryorganicchemicalsaminoxidationofpropenetoacrylonitrileCH2=CHCH3+NH3+1/2O2CH2=CHCN+3H2OP-Mo-Bi,multi-componentcatalystOxidationofethylenetoaldehydeCH2=CH2+1/2O2CH3CHOPdCl2/CuCl2complexingcatalysSeveralimportantappliedfieldsofcatalysisManufacturingfinechemicalsInwholepatentsinvolvingcatalysisissuedinJapan,thosedealingwithfinechemicalshadbeenincreasedbyaboutthreetimes,from7.1%to24.8%duringtheperiodof1975-1984.EnvironmentprotectionCatalystforautomobiletailgas.ConvertingNOxandCODesulfuratingcatalystforfluegasMainresearchinterestsMechanismofcatalysisKineticsofcatalyzedreactionTherelationbetweencatalyticpropertiesandstructureofcatalystDevelopingnewcatalystsandnewcatalytictechniquesSomefrontierresearchdirectionHeterogenelizationofhomogeneouscatalysisCatalysisinC1chemistry:convertingCO,CO2,andCH4toproductsofeconomicalimportanceFilm(membrance)catalysisBiologicalEnzymecatalysisPhotocatalysisandphotosynthesisComputeroptimizationincatalystdesignandpreparationSpecialistsystemPatternrecognitionArtificialintelligence§1.2ConceptanddefinitionCatalysisTheconceptofcatalysisisamethodofcontrollingtherateanddirectionofachemicalreactionCatalystAcatalystisasubstancethatincreasestherateofreactiontowardstoequilibriumwithoutbeingappreciablyconsumedintheprocess.Catalystcannotchangetheultimateequilibriumdeterminedbythermodynamics.Itsroleisrestrictedtoacceleratingtherateofapproachingtoequilibrium.§1.2ConceptanddefinitionCatalyzedreactionThebasicconceptisthatacatalyzedreactioninvolvesthechemisorptionofoneormoreofthereactantsontothesurfaceofthecatalyst,rearrangementofthebondinganddesorptionoftheproduct.Ingeneral,catalystparticipatesincertainintermediatestepsofareactiontoalterthereactionpathwayandtolowertheactivationenergy,henceincreasesthereactionrateconstant.catalystsurfacereactantAintermediateMproductPEaMEa’PA§1.2Conceptanddefinitionk=Aexp(-Ea/kT)whenEadecreaseskhasgotincreasedInfewercases,catalystmayalsochangethemagnitudeofpre-exponentialfactor§1.3ClassificationofcatalysisBiologicalenzymecatalysis2H2O22H2O+O2enzymeHomogeneouscatalysisCH3COOC2H5C2H5OH+CH3COOHH2SO4themostimportanthomogeneouscatalystissolubletransitionmetalcomplex§1.3ClassificationofcatalysisHeterogeneouscatalysisSolidacidicandbasiccatalystCH3OHgasolineZSM-5zeolite,acidic2CH4+O2C2H4+2H2OMgO,basicSupportedcatalystCH4+H2OCO+3H2(syngas)Ni/Al2O3Oxidecatalyst,insulatororsemiconductorCO+H2CH3OHCuO/ZnOMetalcatalystC6H6(Benzene)+3H2C6H12(Cyclohexane)Ni§1.4Activity,selectivityandlifetimeofcatalystActivityconversionXA=(nA0-nA)/nA0100%nA0:initialquantityofreactantnA:residualreactantattheendofreactionSpace-timeyield(especialforsolidcatalyst)quantityofproductformedperunittimeperunitvolumeofcatalystKmol/hr·m3g/min·L§1.4Activity,selectivityandlifetimeofcatalystSelectivityk1CH3CHO(P)+H2Cu,250ºCC2H5OH(A)k2C2H4(B)+H2OAl2O3,350ºCselectivefactors=k1/k2selectivitysP=a/pnP/(nA0-nA)100%orsP=nP/(nP+nB)100%herea=1andp=1StoichimetriccoefficientYieldy=a/pnP/nA0100%y=XAsP§1.4ExampleForthereactionofmethanoldehydrogentomethylaldehydeCH3OHHCHO+H2Ifthemethanolfeedrateis5.0kmol/hrandtheproductis3.8kmol/hraldehydewith0.7kmol/hrmethanolasresidualconversionXAXA=(nA0-nA)/nA0100%=(5.0-0.7)/5.0100%=86.0%selectivitysPsp=a/pnP/(nA0-nA)100%=3.8/(5.0-0.7)100%=88.4%yieldyy=nP/nA0100%=3.8/5.0100%=76.0%§1.4LifetimeofcatalystdeactivationofcatalystAcatalystloseitsactivityoritsselectivityforawidevarietyofreason