20100909 化工專業(yè)英語練習題 題目 1

1、僅供個人參考1)過程指引起一種物質(zhì)和(多種)物質(zhì)的混合物發(fā)生物理變化或化學(xué)變化的操作或一系列操作。進入過程的物料稱之為對該過程的輸入或進料，而離開的物料稱之為輸出或產(chǎn)品。Aprocessisanyoperationorseriesofoperationsthatcausesaphysicalorchemicalchangeinasubstanceoramixtureofsubstances.Thematerialthatentersaprocessisreferredtoasinputorfeedtheprocess,andthatwhichleavesiscalledoutputorprod

2、uct.2)B.Braun成立于1839年，從一個生產(chǎn)醫(yī)藥產(chǎn)品的小生產(chǎn)廠家不斷發(fā)展，以成為一個跨國公司，現(xiàn)經(jīng)營醫(yī)藥產(chǎn)品、醫(yī)療技術(shù)、藥物及生物技術(shù)Foundedin1839fromasmallproductionfirmforpharmaceuticalproducts,B.Braunhasgrownsteadilyintoamultinationalcompanydealingwithmedicalproducts,medicaltechnology,pharmaceuticalandbiotechnology.1）Inthesamewaythatacomplexplantcanbedivid

3、edintobasicunitoperations,sochemicalreactionsinvolvedintheprocessindustriescanbeclassifiedintocertaingroups,orunitprocesses(e.g.,polymerizations,，etherifications,andnitrations),havecommoncharacteristics.復(fù)雜的工廠可劃分為基本的操作單元一樣，過程工業(yè)中涉及的化學(xué)反應(yīng)也可劃分為一定的單元過程（如聚合、酯化、和硝化）它們具有共同的特性。2）Thenotionofaprocessingplantenc

4、ompassinganumberofoperations,suchasmixing,evaporation,andfiltration,andoftheseoperationsbeingessentiallysimilar,whatevertheproduct,ledtotheconceptofunitoperations.包括的一系列操作，如混合、蒸發(fā)、過濾，無論產(chǎn)物是什么，這些操作都基本相同，從而導(dǎo)致了單元操作的概念。3）Thechemicalengineermustworkcloselywiththechemistinordertounderstandthoroughlythechemi

5、stryinvolvedintheprocessandtomakesurethatthechemistgetsthereactionkineticdataandthephysicalpropertydataneededtodesign,operate,andoptimizetheprocess化學(xué)工程師必須與化學(xué)家緊密合作，以完全了解過程中涉及的化學(xué)知識，并要弄清化學(xué)家是否得到了過程設(shè)計、操作及優(yōu)化所需的化學(xué)動力學(xué)數(shù)據(jù)及物性數(shù)據(jù)。4）Allfluidsarecompressible-evenwater-theirdensitywillchangeaspressurechanges.Unders

6、teadyconditions,andprovidedthatthechangesinpressurearesmall,itisusuallypossibletosimplifyanalysisoftheflowbyassumingitisincompressibleandhasconstantdensity.所有的液體是可壓縮的甚至水他們的密度變化是壓力的變化。穩(wěn)定的條件下的變化,并給出在壓力很小,通?？梢院喕僭O(shè)流量分析是不可壓縮的和有一定的密度。5）Inaregionsuchasouterspace,whichisvirtuallyvoidofgases,thepressureisess

7、entiallyzero.Suchaconditioncanbeapproachedverynearlyinalaboratorywhenavacuumpumpisusedtoevacuateabottle.Thepressureinavacuumiscalledabsolutezero,andallpressuresreferencedwithrespecttothiszeropressurearetermedabsolutepressures.在某一區(qū)域內(nèi)如太空,這幾乎是無用的氣體,壓力本質(zhì)上是零。這樣的條件下,能夠到達幾乎在實驗室里當真空泵是用來撤離一個瓶子里。在真空壓力稱為絕對零,所有

8、的壓力參考關(guān)于這個零壓稱為絕對壓力。Manypressure-measuringdeviceslikethemanometermeasurenotabsolutepressurebutonlydifferenceinpressure.Thereferencepressureisactuallytheatmosphericpressure.Wheneveratmosphericpressureisusedasareference,thepossibilityexiststhatthepressurethusmeasuredcanbeeitherpositiveornegative.Whenthi

9、sdifferenceispositive,thistypeofpressurereadingiscalledgagepressure.許多壓力的測量設(shè)備,如壓力,但是不是絕對壓力唯一的不同。參考壓力實際上是大氣壓力。每當氣壓作為參考,有可能存在著壓力從而測量可以積極還是消極的。當這種差異是積極的,這類型的壓力閱讀被稱為規(guī)的壓力。不得用于商業(yè)用途僅供個人參考，1)圖7所示的一個基本實例，是石油化工某部分的一個完整設(shè)計（主要是單元操作，換熱網(wǎng)絡(luò)和控制回路）。系統(tǒng)包括反應(yīng)和分離部分。反應(yīng)屬于催化反應(yīng)，由于催化劑的失活（deactivation），其轉(zhuǎn)化率在幾個月的操作周期內(nèi)是變化的。當催化劑活性較

10、低時，反應(yīng)轉(zhuǎn)化率下降，相應(yīng)地精餾塔的進料發(fā)生變化。精餾塔有自己的控制系統(tǒng)（未畫出）以保證塔底產(chǎn)物(bottomproduct)組成保持穩(wěn)定。塔頂組分（循環(huán)）組成是可變的，以抵消（toaccommodate）催化劑失活的影響。Figure7showsthebasecase,acompletedesign(mainunitoperations,heatexchangernetwork,andcontrolloops)forpartofapetrochemicalsprocess.Thesysteminvolvesreactionandseparation.Thereactioniscatalyti

11、candconversionisvariableoverperiodsofseveralmonthsduetocatalystdeactivation.Duringtimesodlowcatalystactivity,conversionfallsoffandconsequentlythecompositionofthedistillationfeedstreamchanges.Thedistillationcolumnhasitsowncontrolsystem(notshown),whichisusedtoensurethatthecompositionofthebottomproduct

12、iskeptconstant.Thetopproductcomposition(recycle)isvariabletoaccommodatetheeffectofcatalystdeactivation.2)化學(xué)工程是處理那些原材料變化或分離成有用產(chǎn)品的工業(yè)過程?；瘜W(xué)工程師必須能對全流程以及所用的設(shè)備進行開發(fā)、設(shè)計和操作；選擇合適的原料；高效、安全、經(jīng)濟地操作工廠，同時確保生產(chǎn)的產(chǎn)品能滿足顧客的要求Chemicalengineerhastodealwithindustrialprocessesinwhichrawmaterialsarechangedorseparatedintouseful

13、products.Chemicalengineersmustdevelop,design,andengineerboththecompleteprocessandtheequipmentused;choosetheproperrawmaterials,operatetheplantsefficiently,safely,andeconomically;andseetoitthatproductsmeettherequirementssetbycustomers1)Theaboveexamplesteachusanimportantlesson,althoughitisthechemistswh

14、omakeanddiscoverthenewchemicalswhichmayhavespecialproperties,aconsiderableinputfromengineersandtechnologistsmayberequiredbeforethechemicalcanbeprocessedandconvertedintoasuitableforminwhichitcanbeused.上述這些實例給我們一個主要的啟示：雖然化學(xué)家制備并開發(fā)了具有特性性質(zhì)的新的化學(xué)物質(zhì)，但是要將這些化學(xué)物質(zhì)加工并轉(zhuǎn)化為可實用的合適形態(tài)，還需要工程師和技術(shù)人員投入大量的工作。2)“Unitoperati

15、ons”evolvedinmeetingtheneedofeconomiclarge-scalemanufactureofcommodityproducts.Theconceptofunitoperationsheldthatanychemicalmanufacturingprocesscouldberesolvedintoacoordinatedseriesofoperationssuchaspulverizing,drying,roasting,crystallizing,filtering,evaporating,distilling,electrolyzing,andsoon.單元操作

16、已發(fā)展成為滿足商品大規(guī)模生產(chǎn)的需要，其概念認為：任何化學(xué)生產(chǎn)過程可分解為一系列同等的操作，如粉碎、干燥、焙燒、結(jié)晶、過濾、蒸發(fā)、蒸餾、電解等。3)Theterm“chemicalengineer”impliesthatthepersonisprimarilyanengineerwhosefirstprofessionalconcerniswithmanufacturingprocessesmakingsomething,ormakingsomeprocesswork.Theadjective“chemical”impliesaparticularinterestinprocesseswhich

17、involvechemicalchanges.術(shù)語“化學(xué)工程師”意味著人主要是一個工程師的第一個專業(yè)的關(guān)心的是制造過程做活兒,或做一些過程的工作。這個形容詞“化學(xué)”意味著一個特定的興趣涉及的化學(xué)變化過程。1）除對恒定平均值(meanvalues)可能的微小漲落外，如果一個過程的所有變量(variables)（即：所有溫度、壓力、體積、流速等）的值都不隨時間變化，該過程可認為是處于穩(wěn)定操作。如有任何過程變量隨時間變化，則可稱為處于過度態(tài)或非穩(wěn)態(tài)。將其本質(zhì)而言，間歇過程和半間歇過程是非穩(wěn)定態(tài)，而連續(xù)過程是穩(wěn)態(tài)或過度態(tài)。Ifthevaluesofallthevariablesinaprocess(e

18、.g.alltemperatures,pressures,volumes,flowrates,etc.)donotchangewithtime,exceptpossiblyforminorfluctuationsaboutconstantmeanvalues,theprocessissaidtobeoperatingatsteadystate.Ifanyoftheprocessvariableschangewithtime,transientorunsteady-stateoperationissaidtoexist.Bytheirnature,batchandsemibatchprocess

19、areunsteady-stateoperations,whereascontinuousprocessesmaybeeithersteadystateortransient不得用于商業(yè)用途僅供個人參考2）合成有機化合物可定義為從天然存在的原料（如石油、天然氣、煤）中衍生出的產(chǎn)品，這些原料至少要經(jīng)過一種化學(xué)反應(yīng)過程（如氧化反應(yīng)、加氫反應(yīng)、鹵化反應(yīng)halogenations、磺化反應(yīng)sulfonation,或烷基化反應(yīng)）。Syntheticorganicchemicalscanbedefinedasderivativeproductsofnaturallyoccurringmaterials(p

20、etroleum,naturalgasandcoal),whichhaveundergoneatleastonechemicalreaction,suchasoxidation,hydrogenation,halogenation,sulfonation,oralkylation.1）Apilotplantisacollectionofequipmentdesignedandconstructedtoinvestigatesomecriticalaspectsofaprocessoperationorperformbasicresearch.Itisatoolratherthananinits

21、elf.Apilotplantcanrangeinsizefromalaboratorybench-topunittoafacilityonlymarginallysmallerthanacommercialunit.Thepurposesforitsconstructionandoperationcanvarywidely:confirmingfeasibilityofaproposedprocess;providingdesigndata;determiningtheeconomicfeasibilityofanewprocess;determiningoptimummaterialsof

22、construction;testingoperabilityofacontrolscheme;determiningtheextentofplantmaintenance;producingsufficientqualitiesofproductformarketevaluation;obtainingkineticdata;screeningcatalysts;providingareasofadvancedtechnology;providingdataforsolutionstoscale-upproblems;providingtechnicalsupporttoanexisting

23、processorproductassessingprocesshazards;determiningoperatingcosts;optimizinganexistingprocess;andperformingbasicprocessresearch.中試工廠是用于研究過程操作中某些關(guān)鍵問題或進行基礎(chǔ)研究的一整套設(shè)備。它是研究手段而不是研究目的。中式工廠的規(guī)模，可從實驗室小型實驗設(shè)備直至比工業(yè)裝置的外形略小一點的裝置。建立并進行中試操作的目的很多：檢驗所設(shè)想過程的可行性；提供設(shè)計數(shù)據(jù)；確定新過程在經(jīng)濟上的可行性；確定最佳的施工材料；檢驗控制系統(tǒng)的可操作性；確定工廠的維護范圍；生產(chǎn)足夠量的產(chǎn)

24、品以供市場評價；獲取動力學(xué)數(shù)據(jù)；為先進技術(shù)提供試驗基地；提供解決放大問題的數(shù)據(jù)；為以有過程或產(chǎn)品提供技術(shù)支持；評定過程的危險程度；確定操作費用；優(yōu)化現(xiàn)有工藝；進行基礎(chǔ)過程研究。2)Abatchreactorisusedforsmall-scaleoperation,fortestingnewprocessesthathavenotbeenfullydeveloped,forthemanufactureofexpensiveproducts,andforprocessesthataredifficulttoconverttocontinuousoperations.Thereactorcanbe

25、chargedthroughtheholesatthetop.Thebatchreactorhastheadvantageofhighconversionsthatcanbeobtainedbyleavingthereactantinthereactorforlongperiodsoftime,butitalsohasthedisadvantagesofhighlaborcostsperbatchandthedifficultyoflarge-scaleproduction.間歇反應(yīng)器用于小于小規(guī)模生產(chǎn)，用于試驗尚未完全開發(fā)成功的新過程，還用于生產(chǎn)昂貴的產(chǎn)品，以及那些難于實現(xiàn)連續(xù)化操作的過程。

26、間歇反應(yīng)器可以從頂部加料。延長反應(yīng)物在反應(yīng)器的停留時間可以獲得較高的轉(zhuǎn)化率，這是間歇反應(yīng)器的優(yōu)點，而其缺點在于每個周期的勞動成本高及難以進行大規(guī)模生產(chǎn)。1）異庚烷由丁烯和異丁烷在濃硫酸的乳化液(emulsion)中反應(yīng)生產(chǎn)。過程的新鮮進料以40,000kg/h的速率加入。其中含25.00mole%的異丁烷、25.00mole%丁烯和50.00mole%的正丁烷，后者在過程中是化學(xué)惰性的。部分反應(yīng)器的出料（effluent）循環(huán)至反應(yīng)器的進口。其余部分流入分層槽（settler）在槽中水相（硫酸）和烴相得以分離。酸循環(huán)至反應(yīng)器，烴則進入精餾塔。塔頂餾出物含正丁烷和異庚烷，而塔底產(chǎn)物全為異丁烷循環(huán)

27、至反應(yīng)器。Isooctaneisproducedbythereactionofbutylenesandisobuteneinanemulsiontheconcentratedsulfuricacid.Thefreshfeedtotheprocessflowsatarateof40000kg/h,andcontains25mole%isobutene,25%butylenes,and50%n-butane,whichischemicallyinertinthisprocess.Aportionofthereactoreffluentisrecycledtothereactortheinlet,a

28、ndtheremainderpassestoasettler,inwhichtheaqueous(sulfuricacid)andhydrocarbonphasesareallowedtoseparate.Theacidisrecycledtothereactor,andthehydrocarbonspasstoadistillationcolumn.Theoverheadfromthecolumncontainsisooctaneandn-butane,andthebottomsproduct,whichisrecycledtoreactor,containsonlyisobutene.不得

29、用于商業(yè)用途僅供個人參考2)流化床催化裂化裝置（cracker）的典型簡圖見圖15。裝置的特征是有兩個巨大的容器（vessel），一個用于使進料在熱催化劑上進行反應(yīng)，另一個用空氣燒去碳以使用過的（spent）催化劑再生。新型（newer）分子篩催化劑的活性如此之高，使得物料和催化劑之間的接觸時間必須急劇減少，否則石油就會過度裂解(overcrack)而得到不希望得到的氣體和焦碳。AtypicaldiagramofafluidcatalyticcrackerisshowninFig.15.Theunitischaracterizedbytwohugevessels,onetoreadthefee

30、dwithhotcatalystandtheothertoregeneratethespentcatalystbyburningoffcarbonwithair.Theactivityofnewermolecular-sievecatalystsistogreatthatthecontacttimebetweenfeedandcatalystisreduceddrastically.Ifnot,theoilwillovercracktogiveunwantedgasesandcoke.1)Whiletechnicaladvancesandefficiencyimprovementsinspec

31、ificunitoperationsareoccurringthetime,thebigstoryisthehybridizationofprocesses.Combiningindividualunitoperations,suchasreaction,andheatexchange,intolarger,concurrentoperationswillbemajortrendomupcomingyears.Technologiessuchasreactivedistillation,catalyticmembranes,andphase-transfercatalystsallrepres

32、entexamplesofhybridizedprocesseswherereactionandseparationarecombined.當技術(shù)進步和提升效率發(fā)生在特定單元操作,大的故事是有關(guān)雜交過程。結(jié)合個人單元操作,如反應(yīng),與換熱,成規(guī)模更大、并行操作將主要趨勢即將到來的市的年。技術(shù),如反應(yīng)蒸餾、催化膜、相轉(zhuǎn)移催化劑的例子都表現(xiàn)化過程中,反應(yīng)和分離的總和。2)Theformulationofthethermodynamicequilibriumproblemandthemethodologiesusedforitssolutionarepresentedinthischapter.The

33、resultingequationsneedanumberofpurecomponentandmixtureequilibriumproperties,which,whenevernotexperimentallyavailableattheconditionsofinterest,mustbeestimated.本章給出了對熱力學(xué)平衡問題的描述及其解決方法。所導(dǎo)出的方程需要大量純組分的平衡性質(zhì)及混合物的平衡性質(zhì)，如果在要求的條件下，以實驗方式得不到這些平衡數(shù)據(jù)，就必須估算這些數(shù)據(jù)。Mostoftheproblemsinchemicalengineering,however,aremultiv

34、ariableandnonlinear,withconstraints,andoftenrequiretheuseofdiscretevaluedvariables.Also,whileoptimizationisaconceptuallypowerfulframework,itsimpacthasbeensomewhatlimitedinpracticeduetothelackoftoolsthatfacilitatetheformulationandsolutionoftheseproblems.然而，化學(xué)工程中大多數(shù)問題都是多變量、非線性、有約束條件的問題還常常需要利用離散變量。此外，雖

35、然優(yōu)化概念上很有效的構(gòu)想，但由于缺乏描述問題和求解問題的簡便工具，使得優(yōu)化的效果在實用上有一定的局限性。1)因為產(chǎn)物氨的分子的體積比反應(yīng)物的體積小，所以提高壓力會提高氨的平衡轉(zhuǎn)化率。提高溫度對平衡產(chǎn)生相反的效應(yīng)，但會明顯（greatly）提高反應(yīng)速率。溫度對平衡的負效應(yīng)又兼具對反應(yīng)速率很強的正效應(yīng)，對其他許多反應(yīng)也是常見的，為此，需要對各種條件精致地權(quán)衡以確保得到令人滿意（good）的操作條件，獲得可能的利潤。較快的反應(yīng)速率意味著減小設(shè)備尺寸，因而相應(yīng)地降低設(shè)備成本。Becausetheproductmolecule,ammonia,hasalowervolumethanthereactant

36、molecules,theequilibriumyieldofammoniaisincreasedbyincreasingpressure.Temperatureincreaseproducestheoppositeeffectontheequilibrium,butincreasestherateofreactiongreatly.Thisnegativetemperatureeffectonequilibriumcombinedwithastrongpositiveeffectonrateiscommontomanyotherreactionsandrequiresanicebalance

37、ofassuregoodoperatingconditionsandtomakeprofitspossible.Greaterratemeansreducedequipmentandconsequentequipmentcost.2)硝酸廣泛用于生產(chǎn)無機硝酸鹽和有機硝酸酯、用于各種金屬處理，以及用于光刻（photoengraving）。硝酸生產(chǎn)是鉑-銠（platinum-rhodium）催化劑上將氨氧化成一氧化氮（nitricoxide），一氧化氮氧化成二氧化氮，然后將二氧化氮溶解于水。降低產(chǎn)品速率的副反應(yīng)是氨氧化成氮氣和水蒸氣。Nitricacidisusedextensivelyforth

38、eproductionofinorganicandorganicnitrates,formetaltreatmentofvariouskinds,andforphotoengraving.Itisproducedbyoxidizingammoniatonitricoxideoveraplatinum-rhodiumcatalyst,oxidizingthenitricoxidetonitrogendioxide,anddissolvingtheNO2inwater.Asidereactionthatlowerstheproductyieldistheoxidationofammoniatoni

39、trogenandwatervapor.不得用于商業(yè)用途僅供個人參考3）許多石油化工產(chǎn)品從木材制得，首先將木材轉(zhuǎn)化為合成氣，合成氣然后轉(zhuǎn)化為甲醇或者氨，通過進一步的加工就能夠獲得所需的產(chǎn)品。圖1歸納了一些能夠以甲醇和氨這兩種基本中間體生產(chǎn)的化工產(chǎn)品衍生物。Awidevarietyofpetrochemicalscanbeproducedfromwoodbyfirstconvertingthewoodtosynthesisgas,whichcanthenbeconvertedtoeithermethanolorammoniaandfurtherprocessedtoproducethedesir

40、edchemicalproducts.Fig.1summarizessomeofthechemicalderivativesthatcanbeproducedfromthetwobasicintermediateproducts.1)Muchequipmentfortheseparationofliquidsandfinelydividedsolidswasinventedindependentlyinanumberofindustriesandisofdiversecharacter.Thesedevelopmentshaveoccurredwithoutbenefitofanybutthe

41、mostgeneraltheoreticalconsiderations.Evenatpresent,theselectionofequipmentforspecificsolid-liquidseparationapplicationsislargelyaprocessofscale-upbasedondirectexperimentationwiththeprocessmaterial.在許多工業(yè)部門獨立開發(fā)出許多用于分離液體和細微固體顆粒的設(shè)備，它們各具特性。這些開發(fā)只是依據(jù)一些最基本的理論。即使在目前，為特定固-液分離過程的設(shè)備選型主要還是一個以工藝物料直接實驗結(jié)果為基礎(chǔ)的放大過程。2

42、）Theunitoperationsarelargelyusedtoconducttheprimarilyphysicalstepsofpreparingofreactants,separatingandpurifyingtheproducts,recyclingunconvertedreactants,andcontrollingtheenergytransferintooroutofthechemicalreactor.Wealsocansaythat,theunitoperationsdealmainlywiththetransferandchangeofenergyandthetran

43、sferandchangeofmaterialsprimarilybyphysicalmeansbutalsobyphysical-chemicalmeans.設(shè)備操作在很大程度上是用來進行主要物理步反應(yīng)物料配比、準備分組分離純化回收得救產(chǎn)品反應(yīng)物料配比、和控制能量傳遞進、出化學(xué)反應(yīng)器。我們也能說,設(shè)備操作應(yīng)對主要是由于轉(zhuǎn)會和改變的能量和轉(zhuǎn)移和改變的材料主要由物理方法還理化手段。1Unlikemanyproductswhosestructureandreactionswerewellknownbeforetheirindustrialapplication,somepolymerswerepr

44、oducedonanindustrialscalelongbeforetheirchemistryorphysicswerestudied.和許多的產(chǎn)品結(jié)構(gòu)和反應(yīng)是非常熟悉的在他們的工業(yè)應(yīng)用,一些聚合物工業(yè)生產(chǎn)規(guī)模生產(chǎn)化學(xué)或物理他們之前的很長一段時間進行了研究。2Configurationalisomerismisthenduetothepresenceinthemoleculeofoneormoredissymmetriccenters,inthesimplestcaseasymmetriccarbonatomseachofwhichcanhave(R)and(S)absoluteconfi

45、guration;and,or,tothepresenceofdoublebondswhichcangivecis-andtrans-geometricalisomers.然后構(gòu)型正異構(gòu)由于存在一個或多個分子不對稱中心,在最簡單的情況下不對稱碳原子其中的每一個都可以有(R)和(S)絕對的配置;或者雙聯(lián)系的存在能給順和轉(zhuǎn)化幾何異構(gòu)體。3Thehomologesofbenzenearethosecontaininganalkygrouporalkylgroupsinplaceofoneormotehydrogenatoms.那些含有烷基團體或烷基官能團的同分異構(gòu)體的苯必須代替一個塵粒氫原子構(gòu)成。4

46、Objectionablehydrogensulfideisremovedfromsuchagasorfromnaturallyoccurringhydrocarbongasesbywashingwithvariousalkalinesolutionsinwhichitisabsorbed.討厭的硫化氫將這些氣體或自然發(fā)生的碳氫化合物氣體從用各種堿液中,這是吸收。5Gasabsorptionisanoperationinwhichagasmixtureiscontactedwithaliquidforthepurposesofpreferentiallydissolvingoneormorec

47、omponentsofthegasandtoprovideandtogiveasolutionoftheseintheliquid.氣體吸收的一種操作聯(lián)系的混合氣體與液體溶解優(yōu)先為目的的一個或多個組件提供的氣體,把解決這些處在液體里。不得用于商業(yè)用途僅供個人參考6.Thecontinuousprocessalthoughrequiringmorecarefullydesignedequipmentthanthebatchprocess,canordinarilybehandledinlessspace,fitsinwithothercontinuousstepsmoresmoothly,and

48、canbeconductedatanyprevailingpressure.連續(xù)過程雖然需要更多精心設(shè)計的設(shè)備比批量生產(chǎn)、通常能處理較少的空間,適用于其它連續(xù)舞步順利,可進行任何流行的壓力。7Normally,inevaporationthethickliquidisthevaluableproductandthevaporiscondensedanddiscarded.Mineral-bearingwaterisoftenevaporatedtogiveasolid-freeproductforboilerfeed,forspecialprocessrequirements,orforhum

49、anconsumption.Thistechniqueisoftencalledwaterdistillation,buttechnicallyitisevaporation.Inonespecificsituation,however,thereverseistrue.一般來說,在蒸發(fā)漿是有價值的產(chǎn)品和蒸汽被壓縮并且丟棄。含礦物質(zhì)的水是經(jīng)常蒸發(fā)給無固相產(chǎn)品對于鍋爐,為特別的工藝的要求,或給人食用。這一技術(shù)是經(jīng)常被稱為“水蒸餾,但技術(shù)上講是蒸發(fā)。在某一情況下,然而,剛好相反。1）將甲烷轉(zhuǎn)化成石油化工產(chǎn)品的最重要的工藝路線是借助于氫氣，或借助于氫氣和一氧化碳的混合氣，后者稱之為“合成氣”(syn

50、thesisgas)。以煤來生產(chǎn)氫氣和一氧化碳混合物最初實現(xiàn)工業(yè)化（toestablishindustrially）是通過著名的水煤氣反應(yīng)（water-gasreaction）。Willthemethaneintopetrochemicalproductsisthemostimportantprocessroutebyhydrogen,orbyhydrogenandcarbonmonoxiderichermixture,thelattercalledsyngas.Withcoaltoproducehydrogenandcarbonmonoxidemixturefirstrealizationi

51、ndustrializationisthroughthefamousserni-watergasreactions.1）Whentwoobjectsatdifferenttemperaturesarebroughtintothermalcontact,heatflowsfromtheobjectatthehightemperaturetothatatthelowertemperature.Thenetflowisalwaysinthedirectionofthetemperaturedecrease.Themechanismsbywhichtheheatmayflowarethree:cond

52、uction,convention,andradiation.當兩個物體在不同的溫度被帶至接觸熱,熱源自于物體的高溫溫度較低的物體。網(wǎng)絡(luò)流的方向一直在溫度降低。所采用的機制流熱可以有三個:辦理、會議展覽、和輻射等。economicandsafe2）Tounderstandthecontributionswhicharefeasibleanddesirablefromthetwounderstandingoftheindividualknowledgebases,perspectivesandinterests.Putsimple,thecontributionofthechemististoi

53、dentifythevariouscombinationsofchemicals,catalystsandconditionswhichwillleadtooptimalconversionstothedesiredproductorproducts,theengineerscontributionistoidentifypractical,equipmentconfigurationswhichwillallowcircumstancestobeachieved.為了理解化學(xué)家和化學(xué)工程師在過程開發(fā)活動中做出的既可行又合乎需要的貢獻，必須了解他們各自的知識基礎(chǔ)、思考問題的方法及興趣所在。簡言

54、之，化學(xué)家的貢獻在于尋找化學(xué)物、催化劑和反應(yīng)條件的組合，以達到生產(chǎn)所需產(chǎn)品的最優(yōu)轉(zhuǎn)化率，而工程師的貢獻在于確定實用、經(jīng)濟、安全的設(shè)備構(gòu)型，使這些條件得以實現(xiàn)。3）Theremovalofoneormoreselectivecomponentsfrommixtureofgasesbyabsorptionintoasuitableliquidisthesecondmajoroperationofchemicalengineeringthatisbasedoninterphasemasstransfercontrolledlargelybyratesofdiffusion.通過吸收將氣體混合物中一個

55、或多個組分脫除到合適的液體中去，是第二大基于擴散速率控制的相際傳質(zhì)的化工操作。4）chemicaloxygendemand.Abbrev.COD.Ameasureoftheamountofpotassiumdichromateneededtooxidizereducingmaterialinawatersample.Itisexpressedastheconcentrationofmillion,chemicallyequivalenttotheamountofdichromateconsumed.Itisgenerallyhigherthanthebiologicaloxygendemand

56、,assomematerials,suchascellulose,willreactwithdichromatebutnotwithoxygenunderbiologicalconditions.化學(xué)需氧量（COD）氧化水樣品中還原物質(zhì)所需重鉻酸鉀量的一種亮度，化學(xué)需氧量濃度為ppm，化學(xué)當量等于消耗的重鉻酸鹽總量?；瘜W(xué)需氧量通常大生物耗氧量，因為有些物質(zhì)（如纖維素）在生物條件下可與重鉻酸鹽反應(yīng)而不與氧反應(yīng)。不得用于商業(yè)用途僅供個人參考WestfaliaSeparator從事離心分離(centrifugal)技術(shù)已有近一百年的歷史。生產(chǎn)的設(shè)備用于下列工業(yè)部門：生物工程、化學(xué)與制藥工業(yè)、食品工業(yè)

57、、礦物油加工及廢水處理。WestfaliaSeparator公司通過人力開展研究和開發(fā)工作，使它成為擁有最現(xiàn)代化工藝和系統(tǒng)技術(shù)的專業(yè)公司W(wǎng)estfaliaSeparatorengagedincentrifugalseparationtechnologyhasahistoryofalmostonehundredyears.Productionequipmentusedinthefollowingindustrialsectors:biologicalengineering,chemicalandpharmaceuticalindustry,foodindustry,mineraloilproce

58、ssingandwastewatertreatment.WestfaliaSeparatorcompanythroughthehumanconductresearchanddevelopmentwork,makeitbecomewiththemostmoderntechnologyandsystemtechnologyofprofessionalcompanies1）Thispaperseekstoreviewthevariouspurposeofpilotplantoperationsandshowineachcontextthebenefitswhichcanbeobtainedbytheapplicationofchemicalengineeringexpertiseandtheenhancedbenefitswh