《工程科技化反》课件-PPT.ppt

Chapter03IdealReactorsBATCHREACTORDESIGN1CONTINUOUS-FLOWREACTORS2PLUG-FLOWREACTORS31

3idealreactorsStirredtanksturbularorpacked-bedreactorsthecriterionforidealityintankreactorsisthattheliquidbeperfectlymixed,whichmansnogradientsintemperatureorconcentrationinthevessel.inplug-flowreactors,orPFRs,thereareaxialgradientsofconcentrationandperhapsalsoaxialgradientsoftemperatureandpressure,butintheidealPFRthereisnoaxialdiffusionorconduction.2

BatchReactorDesign

First-orderreactions1Second-orderreactions2ConsecutiveReactions3ParallelReactions4SemibatchReactions53

First-orderreactionsForanirreversiblefirst-orderreationofthetype(3.2)4

First-orderreactionsTheresultisoftengivenintermsofthefractionconverted:(3.3)5

Second-orderreactionsforaunimolecularsecond-orderreation,(3.6)(3.5)(3.4)or6

Second-orderreactionsbimolecularreationWhereR1(3.7)SinceandwithAthelimitingreactant.Let7

Second-orderreactions(3.8)Integrationbetweenlimitsgives(3.10)8

大家有疑问的，可以询问和交流可以互相讨论下，但要小声点9

大家有疑问的，可以询问和交流可以互相讨论下，但要小声点10

Second-orderreactionsR=2.011

ConsecutiveReactionsTheratesofreactiondependontheconcentrationofBintheliquidphase,whichisafunctionofgassolubility,pressure,andagitationconditions.weareoftenconcernedwiththerelativereactionratesandtheselectivity,whichdonotdependontheconcentrationofB,ifthereactionordersarethesameforbothreactions.Thereactionsaretreatedaspseudo-first-order,andequationsaredevelopedforanidealbatchreactorwithirreversiblefirst-orderkinetics:12

ConsecutiveReactions(3.13)(3.12)TheconcentrationofAfallsexponentially,aswasshownearlierinEq.(3.2):(3.11)13

ConsecutiveReactionsThematerialbalanceforproductCisCombiningtheseequationsgives(3.15)(3.14)14

ConsecutiveReactionsIfnoCispresentatthestart,integrationofEq.(3.15)givesTheconcentrationofCgoesthroughamaximumwit