SpecializedEnglishforchemistry化工專業(yè)英語1/35ChemicalEnineeringandTechnology

Lesson3CatalystsforIndustrialProcessesThecriteriaforanindustriallysuccessfulcatalystareverystringent.Criteria（批評、判斷等）標(biāo)準(zhǔn)，準(zhǔn)則(criterion名詞復(fù)數(shù)Stringentadj. 嚴格;迫切;（貨幣）緊縮Thetwomostimportantconsiderationsareactivityanddurability;suitabilityforbasicstudyisnotafactor,andthishasretardedprogressinourunderstandingofhowsuchtechnicalcatalystsreallyoperate.2/35Letusconsiderthetwoprimerequirements.primeadj.最好;首要;最初;基本n.精華;早期;全盛時期;青年vt.使準(zhǔn)備好;填裝;事先指導(dǎo)First,thecatalystmustbeabletoeffectthedesiredreactionatanacceptablerateunderconditionsoftemperatureandpressurethatarepracticable.3/35Chemicaltechnologyhasadvancedtothepointwheretemperaturesashighas1600Kandpressureupto350atm(35MPa)presentnodifficultiesandthermodynamicconsiderationssometimesnecessitatetheirusetoattainreasonableequilibriumyieldsofproducts.

Necessitatevt. 使…成為必要，需要;強迫，迫使equilibriumn. 平衡，均勢;平靜4/35Ifhowevergoodyieldscanbeobtainedatlowtemperaturesandpressures,thenthereiseveryincentivetofindacatalystthatwilloperateunderthemildestpossibleconditions,sincetheuseofextremeconditionsisverycostly.Incentiven.動機;刺激;誘因;勉勵adj.刺激性;勉勵性質(zhì)Mildest適當(dāng)適中Itisconcurrentlyimportantthatside-reactionsareminimal,especiallythoseleadingtopoisoningordeactivationthroughcarbondeposition.5/35Second,thecatalystmustbeabletosustainthedesiredreactionoverprolongedperiods:insomeprocesses,acatalystlifeofseveralyearsisnotuncommon,andiseconomicallynecessary.Prolongvt. 延長，拉長;拖延，延期Clearlythelongeritlasts,thesmallerthecontributionthatitsinitialcostmakestotheoverallcostoftheprocesswillbe.initialadj. 最初;開始;首字母6/35Initialcostisrarelyofover-ridingimportance:itisusuallycheaperinthelongruntouseanexpensivecatalystthatwilllastalongtimethanacheaponethathastobereplacedfrequently.Thechiefcausesofdeteriorationinuseare:reversiblepoisoningduetoimpuritiesinthereactantsortoside-reactions,andirreversiblephysicalchangesincludinglossofsurfacearea(sintering)ormechanicalfailure.Deteriorationn.惡化;變壞;退化;墮落Irreversibleadj.不可逆;不能翻轉(zhuǎn);不能倒置sinteringn.泉華，燒結(jié)物，熔渣vt.使燒結(jié)7/35Reversiblepoisoningmaywithluckberectifiedbysimpletreatment,suchasoxidationorwashing,withoutremovingthecatalystfromthereactor.Rectifiedadj.[醫(yī)]矯正，調(diào)整v.更正，矯正(rectify過去式和過去分詞);精餾Toguardagainstphysicalchanges,carefulattentionhastobegiventothestrengthofthecatalyst.guardn.警衛(wèi);獄吏，看管;護衛(wèi)隊;防護裝置vt.保衛(wèi)，守護;看管;加防護裝置;慎重使用vi.警覺;警衛(wèi)8/35Thepreferredphysicalformforacatalystisdeterminedentirelybythemannerinwhichitistobeused.Itsparticlesizeisespeciallyfixed,atleastwithinbroadlimits,bythetypeofreactortobeemployed.Aroughcriterioniswhetherornotonecandistinguishseparateparticleswiththenakedeye.Criterionn.（批評、判斷等）標(biāo)準(zhǔn)，準(zhǔn)則;規(guī)范Whenthereactantsaresolelygasesorvapors,thereareonlytwopossiblebasictypesofreactorthatcanbeused.solelyadv. 唯一地;僅僅;獨一無二地;純粹9/35Whenthereactantsaresolelygasesorvapors,thereareonlytwopossiblebasictypesofreactorthatcanbeused.solelyadv. 唯一地;僅僅;獨一無二地;純粹Fixed-bedreactorFluidized-bedreactor10/35Tubularreactorkettlereactor11/35PackedtowerreactorTowerreactor12/35Afixed-bedreactorisoneinwhichatubeispackedwith“coarse”catalystparticlesthroughwhichthereactantsflow.Coarseadj. 粗鄙;粗糙;粗野;粗制濫造Asaresultoftheobstructiontogasflowbytheparticles,apressuredropoccursacrossthebed,andapositivepressurehastobeappliedattheinlettosecureanadequateflow-rate.13/35Thesizeofthepressuredropincraseswithincreasingflow-rateandbedlength,andwithdecreasingparticlesize.Manydifferentshapesandsizesofcatalystparticlesareusedinfixed-bedreactors,andagreatdealofskillandexperiencegoesintochoosingthemostappropriateforagivensetofconditions.appropriateadj. 適當(dāng);恰當(dāng);適當(dāng)v. 盜用;侵吞;撥（?？畹龋?4/35SphericalTrifoliumCylindricalSaddle15/35Dimensionsofmorecommonformsareusuallybetween2mmand2cm.Dimensionsvi.按規(guī)格尺寸切割vt.在…上標(biāo)尺寸n.面積;特點;（長、寬、厚、高等）尺寸;主要性;尺寸(dimension.When,asinthecaseof

ammoniaoxidation,itisdesiredtouseapuremetalcatalystathightemperatureandaveryshorttime.Ammonian.氨;氨水;氨氣16/35Soabedof20to30finely

wovenmetalgaugesisused,thisisanothercatalystformsuitedforuseinafixed-bedreactor.Wovenv.編，織，織成(weave過去分詞);編排;杜撰;（把…）編成gaugesn.測量標(biāo)準(zhǔn)或范圍;尺度，標(biāo)準(zhǔn);測量儀器;評定vt.（用儀器）測量;確定容量，體積或內(nèi)容;評定，判斷;采取17/35Sincemanycatalyzedreactionsarestronglyexothermic,fixed-bedreactorsmustcontainafacilityforremovingtheunwantedenthalpyofreaction.exothermicadj. 發(fā)燒，放出熱量Enthalpyn. [熱]焓;[物]熱函;熱含量HJacketSnaketubeTubularheatexchanger18/35Thismaybedoneinoneortwoways.Amultitubularreactorcontainsalargenumberofreactiontubes,typically2.5cmindiameter,withacoolinggasorliquidflowingbetweenthem.tubularadj. 管系組織;管子形，管狀;管子做成;發(fā)吹管般聲音19/35Alternativelythebedmaybesplitintosections,withprovisionforcoolingthegasinthespacesbetween.Alternativelyadv.二者擇一地;要不然;或者IntermediateindirectheattransferQuenchingwithfeedgas20/35Afurtherimportantandquitedifferentcatalystformisfindingapplication,especiallyinair-pollutioncontrol.Thisistheso-called

monolithicstructure,whichconsistsofablockofceramicmaterial(α-aluminaormullite),throughwhichrunsfineparallelchannels.

monolithicadj.獨塊巨石;整體;龐大Ceramicdj.陶器，與陶器相關(guān);陶瓷，陶制;制陶n.陶瓷制品;陶瓷器;制陶藝術(shù);陶瓷裝潢藝術(shù)aluminan.氧化鋁，礬土;鋁土Mulliten.多鋁紅柱石;莫來石paralleladj.平行;相同，類似;[電]并聯(lián);[計]并行21/35Thestructurescanbemadeinmanydifferentways,eachofwhichresultsinacharacteristicchannelshape.Theblocksareobtainableinarangeofshapesandsizes,andasingleblockwheninsertedinacontainerthereforebehavesasafixed-bedreactor.22/35Becauseofthelowporosityofthematerialfromwhichthesestructurearemade,itisusuallynecessarytoattachathinlayerofamoreporoussubstancetowhichthecatalyticallyactivephasecanadhere.porosityn. 多孔性，有孔性Adherevi.黏附;附著;堅持;追隨vt.使粘附;遵照，堅持;追隨，依附23/35Suchmonolithicstructureshaveseveralclearadvantagesoverpelletsorgranulespackedlooselyinatube.Monolithicadj.獨塊巨石;整體;龐大Pelletsn.小球;小子彈;石彈，炮彈;（貨幣等）圓浮雕v.用小球扔;用子彈射擊;將…制成丸狀;把…弄成小球形granulesn.小顆粒，小硬粒(granule名詞復(fù)數(shù))24/35First,thepressuredropthroughthebedislessforequalquantitiesofcatalyst,thuspermittinghigherspacevelocitiestobeachieved;Velocitiesn. 速度(velocity名詞復(fù)數(shù));高速，快速25/35secondly,thereisnoattritionofthecatalystduetoparticlesrubbingagainsteachotherandformingfinedust.Attritionn. 消耗;消磨;摩擦;（神學(xué)）不徹底懺悔Rubbingn. 拓本，拓印finedust細粉塵;纖塵26/35Theirabilitytowithstand

thermalshockishoweverinsomecaseslimited.Withstandvt.經(jīng)受，承受，禁得起;反抗vi.反抗;耐得住，禁得起Thesecondbasickindofreactorforgaseousreactionsisthefluidizedbed.Gaseousadj. 氣態(tài)，似氣體;無實質(zhì);〈美俚〉不可靠;氣性27/35Herethecatalystconsistsoffineparticles.Andwhenthegasflowupwardsthroughabed,suchpowderattainingacritical

velocitythebedappearsto“boil”:itexpandssignificantly,andtheparticlesareincontinuousmotion.Criticaladj.批評，愛挑剔;關(guān)鍵;嚴重;極主要Velocityn. 速率，速度;周轉(zhuǎn)率;高速，快速28/35Inthisstatethebedissaidtobefluidized.Fluidizedadj.流態(tài)化，沸騰v.使液化，流（態(tài)）化(fluidize過去式和過去分詞)29/35Thebehaviorgivescertainadvantagesoverfixedbeds,forexample,heattransfercharacteriaticsaremuchbetter,andthepressuredropincreasesfarlessquicklywithincreasingflow-rate.

30/35ExercisesVocabulary1Cataystsaresubstanceswhichbytheirmerepresenceevokechemicalreaction.AchangeBimpedeCfortifyDcause2Theessenceofcatalystsisnottheenteringbutthefallingout.AreactionBconsumptionCdepartureDappearance3Inpracticethisdefinitionprovestoorestrictive.AboardBactivatedCvagueDspecific31/354Acatalystisgenerallynotusedupitselfinachemicalreaction.ArequiredBactivatedCconsumedDenergetic5Theactivationenergybarriermustbesurmountedforreactiontotakeplace.AconqueredBpermittedCremovedDdetermined6Catalyststhataccelerate

hydrolysisofestersmustalsoaccelerateesterificationofalchols.AproceedBdevelo