PMI培訓(xùn)資料：換熱設(shè)備Heat Exchanger

換熱設(shè)備HeatExchanger換熱器一、概述在煉油、化工生產(chǎn)中，絕大多數(shù)的工藝過(guò)程都有加熱、冷卻和冷凝的過(guò)程，這些過(guò)程總稱為換熱過(guò)程。傳熱過(guò)程的進(jìn)行需要一定的設(shè)備來(lái)完成，這些使傳熱過(guò)程得以實(shí)現(xiàn)的設(shè)備就稱之為換熱設(shè)備。據(jù)統(tǒng)計(jì)，在煉油廠中換熱設(shè)備的投資占全部工藝設(shè)備總投資的35％～40％,因?yàn)榻^大部分的化學(xué)反應(yīng)或傳質(zhì)傳熱過(guò)程都與熱量的變化密切相關(guān)，如反應(yīng)過(guò)程中，有的要放熱，有的要吸熱，要維持反應(yīng)的連續(xù)進(jìn)行，就必須排除多余的熱量或補(bǔ)充所需的熱量；工藝過(guò)程中某些廢熱或余熱也需要加以回收利用，以降低成本。另外，生產(chǎn)所得的油品或化工產(chǎn)品，需要將其冷卻或冷凝，以便儲(chǔ)存和運(yùn)輸。以上這些與熱量有關(guān)的過(guò)程都需要使用換熱設(shè)備。使用換熱設(shè)備是為了達(dá)到加熱或冷卻的目的，如果將那些需要加熱的流體與需要冷卻的流體，經(jīng)過(guò)換熱設(shè)備相互換熱，既可回收熱量，又可降低冷卻水的消耗。綜上所述，換熱設(shè)備是煉油、化工生產(chǎn)中不可缺少的重要設(shè)備。換熱設(shè)備在動(dòng)力、原子能、冶金及食品等其他工業(yè)部門(mén)也有著廣泛的應(yīng)用。HeatExchanger1.OverviewIntherefining,chemicalproduction,thevastmajorityofprocessesareheating,coolingandcondensationprocess.Theseprocessesarecollectivelyreferredtoasheattransferprocesses.Theheattransferprocessrequiresacertainamountofequipmenttocomplete.Thesedevicesthatenabletheheattransferprocesstoberealizedarereferredtoasheattransferequipment.Accordingtostatistics,intherefineryheattransferequipmentinvestmentaccountedfor35%to40%ofthetotalinvestmentinprocessequipmentbecausemostofthechemicalreactionormasstransferprocessarecloselyrelatedtochangesinheat.Examplesofthereactionprocessaresomehaveexothermic,andsomehaveendothermicinordertomaintainthecontinuousreaction,andhencewemustruleouttheexcessheatorsupplementtherequiredheat;somewasteheatorwasteheatintheprocessalsoneedtoberecycledtoreducecost.Inaddition,theresultingoilorchemicalproductneedstobecooledorcondensedforstorageandtransportation.Alloftheseheat-relatedprocessesrequiretheuseofheattransferequipment.Theuseofheattransferequipmentistoachievethepurposeofheatingorcooling,ifthosewhoneedtoheatthefluidandtheneedtocoolthefluid,heatexchangeequipmentthroughheattransfer,canrecoverheat,butalsoreducetheconsumptionofcoolingwater.Insummary,theheattransferequipmentistheoilrefining,chemicalproductionindispensableimportantequipment.Heatexchangerequipmentinthepower,atomicenergy,metallurgyandfoodandotherindustrialsectorsalsohaveawiderangeofapplications.

二、比較換熱設(shè)備的指標(biāo)

效率要高。效率高就要求其傳熱系數(shù)大，傳熱系數(shù)是指在單位時(shí)間內(nèi)、單位面積上溫度每變化一度所傳遞的熱量。結(jié)構(gòu)緊湊。要使換熱設(shè)備的結(jié)構(gòu)緊湊就要求其比表面積大，比表面積是指單位體積的換熱設(shè)備所具有的傳熱面積，即傳熱面積與換熱設(shè)備體積之比。節(jié)省材料。要做到此點(diǎn)要求其比重量要小，所謂比重量是指單位傳熱面積所耗用的金屬量，即換熱設(shè)備總金屬用量與傳熱面積之比。壓力降要小。流體在設(shè)備中流動(dòng)阻力小、壓力損失就小，節(jié)省動(dòng)力、操作成本降低。要求結(jié)構(gòu)可靠、制造成本低，便于安裝、檢修、使用周期長(zhǎng)。由于要全面滿足上述要求是非常困難的，因而產(chǎn)生了各種各樣的換熱器，以適應(yīng)各種特定的工藝條件。2.ComparisonofheattransferequipmentindicatorsEfficiencyishigh.Highefficiencyrequiresalargeheattransfercoefficient,heattransfercoefficientreferstotheunittime,theunitareaofthetemperatureperpassoncetheheattransfer.Compactstructure.Tomakethestructureoftheheattransferdevicerequiresalargesurfacearea,thespecificsurfaceareareferstotheunitvolumeofheattransferequipmenthasaheattransferarea,thatis,heattransferareaandheattransferequipmentvolumeratio.Savematerial.Todothisrequiresasmallerthanitsweight,theso-calledspecificweightreferstotheunitheattransferareaconsumedbytheamountofmetal,thatis,heattransferequipment,thetotalamountofmetalandheattransferarearatio.Pressuredropissmall.Fluidinthedeviceflowresistanceissmall,thepressurelossissmall,savepower,reduceoperatingcosts.Requiresreliablestructure,lowmanufacturingcost,easytoinstall,repair,longusecycle.Itisverydifficulttofullymeettheaboverequirements,resultinginavarietyofheatexchangerstosuitavarietyofspecificprocessconditions.三、換熱器的分類換熱設(shè)備的分類方法很多，現(xiàn)將幾種常見(jiàn)的分類方法介紹如下：1、按用途分類：分為熱交換器、冷凝器、蒸發(fā)器、加熱器及冷卻器等五類。1）熱交換器：兩種不同溫度的介質(zhì)進(jìn)行熱量交換，使一種介質(zhì)降溫而另一種介質(zhì)升溫，以滿足各自的需要。2）冷凝器：兩種不同溫度的介質(zhì)進(jìn)行熱量交換，其中一種介質(zhì)由汽態(tài)被冷凝成液態(tài)。3）蒸發(fā)器：與冷凝器的操作剛好相反，兩種介質(zhì)中的一種介質(zhì)由液體被蒸發(fā)成汽體。4）加熱器：只單純的完成一種介質(zhì)的加熱升溫的操作。5）冷卻器：如果熱量不回收利用，完成用冷卻劑（如水、空氣）來(lái)冷卻另外一種介質(zhì)的操作的換熱器稱為冷卻器。如用空氣作為冷卻劑的換熱器稱為空氣冷卻器，簡(jiǎn)稱空冷器。2、按材料分類：分為金屬材料和非金屬材料換熱器。3、按結(jié)構(gòu)分類：分為管殼式換熱器和板式換熱器。3.ClassificationofheatexchangersTherearemanywaystoclassifyheatexchangers.Severalcommonclassificationmethodsarepresentedasfollows:1,accordingtotheuseofclassification:dividedintoheatexchangers,condensers,evaporators,heatersandcoolersandotherfivecategories.1)Heatexchangers:Twodifferenttemperaturesofthemediumforheatexchange,sothatamediumcoolingandtheothermediumtemperaturetomeettheirneeds.2)Condenser:Twodifferenttemperaturesofthemediumforheatexchange,oneofthemediafromthevaporstateiscondensedintoliquid.3)Evaporator:Incontrasttotheoperationofthecondenser,oneofthetwomediaisevaporatedfromtheliquidintothevapor.4)Heater:justsimplyheatingonecompletemediumheatingoperation.5)cooler:Iftheheatisnotrecycled,thecompletionoftheuseofcoolants(suchaswater,air)tocooltheoperationofanothermediumheatexchangercalledthecooler.Suchastheairasacoolantheatexchangerknownastheaircooler,referredtoasaircooler.2,bymaterialclassification:metalandnon-metallicmaterialsintoheatexchanger.3,accordingtothestructureclassification:dividedintoshellandtubeheatexchangerandplateheatexchanger.1）管殼式換熱器：特點(diǎn)是圓形的外殼中裝有管束。一種介質(zhì)流經(jīng)換熱管內(nèi)的通道及其相貫通部分（稱為殼程）。它可分為:浮頭式換熱器、U型管式換熱器、套管式換熱器、固定管板式換熱器等。2）板式換熱器：它是由壓成各種形狀的薄板組成傳熱面的，冷、熱兩種介質(zhì)分別在相鄰兩板之間流動(dòng)。常見(jiàn)的板式換熱器有平板式換熱器、傘板式換熱器、螺旋板式換熱器及板殼式換熱器。板式換熱器的傳熱效率雖然較高，但由于其強(qiáng)度低，密封性能差，故其應(yīng)用受到了限制。因此，在石油、化工工業(yè)中應(yīng)用較多的是管殼式換熱器，它已被當(dāng)成傳統(tǒng)的換熱設(shè)備來(lái)加以使用。1)shellandtubeheatexchanger:Featuresareroundshellwithtubebundles.Amediumflowsthroughthechannelintheheattransfertubeanditsintersectingpart(calledtheshell).Itcanbedividedinto:floatingheadheatexchanger,U-tubeheatexchanger,casingheatexchanger,fixedtubeplateheatexchanger.2)plateheatexchanger:itispressedintoavarietyofshapesofthecompositionoftheheattransfersurface,cold,heat,respectively,betweenthetwomediaflowbetweenthetwoplates.Commonplateheatexchangersareflatplateheatexchangers,umbrellaplateheatexchangers,screwplateheatexchangersandplateandshellheatexchangers.Plateheatexchangerheattransferefficiencyishigh,butbecauseofitslowstrength,poorsealingperformance,soitsapplicationhasbeenlimited.Therefore,intheoil,chemicalindustryismoreapplicationofshellandtubeheatexchanger,ithasbeenusedasatraditionalheatexchangerequipmenttobeused.四、管殼式換熱器的總體結(jié)構(gòu)1）固定管板式換熱器這類換熱器的結(jié)構(gòu)簡(jiǎn)單，重量輕，造價(jià)較低，在相同的殼層情況下，可較其他型式的列管換熱器多排一些傳熱管子。但是殼體與管程之間的流體的溫差不能太大，因溫差太大時(shí)，會(huì)產(chǎn)生較大的熱應(yīng)力，使管子與管板結(jié)合處松脫而產(chǎn)生泄漏。此外這類換熱器因管板是固定的，所以在檢修，更換管子或清洗殼層時(shí)，都比較困難。此換熱器適用于殼程介質(zhì)不易結(jié)垢，或是有結(jié)垢但可進(jìn)行化學(xué)清洗的場(chǎng)合；殼壁與管壁因溫度差而引起的膨脹量之差不大，或膨脹差雖大但殼程壓力不高的情況。1)fixedtubeplateheatexchangerThestructureofsuchheatexchangersissimple,lightweight,lowcost,inthesameshellcase,comparedwithothertypesoftubeheatexchangerrowofsomeheattransfertube.However,thetemperaturedifferencebetweentheshellandthepipecannotbetoolarge,becausethetemperatureistoolarge,willhaveagreaterthermalstress,sothatthetubeandthetubeplateatthejunctionofthelooseandproduceleakage.Inaddition,suchheatexchangerbecausethetubeplateisfixed,sointhemaintenance,replacementofthetubeorcleantheshell,aremoredifficult.Thisheatexchangerissuitableforshellmediaisnoteasytoscale,ortherearescalingbutcanbetheoccasionofchemicalcleaning;shellwallandwallduetotemperaturedifferencecausedbytheexpansionofthedifferenceisnotlarge,orexpansiondifferenceislargeShellpressureisnothigh.4.Theoverallstructureofshell-and-tubeheatexchangers總體結(jié)構(gòu)圖OverallStructure2、管殼式換熱器的總體結(jié)構(gòu)以及特點(diǎn)2）浮頭式換熱器浮頭式換熱器的一端管板是固定的。與殼體剛性連接，另一端管板是活動(dòng)的，與殼體之間并不相連?；顒?dòng)管板一側(cè)總稱為浮頭，浮頭式換熱器的管束可從殼體中抽出，故管外壁清洗方便，管束可在殼體中自由伸縮，所以無(wú)溫差應(yīng)力；但結(jié)構(gòu)復(fù)雜、造價(jià)高，且浮頭處若密封不嚴(yán)會(huì)造成兩種流體混合。浮頭式換熱器適用于冷熱流體溫差較大（一般冷流進(jìn)口與熱流進(jìn)口溫差可達(dá)110℃），介質(zhì)易結(jié)垢需要清洗的場(chǎng)合。在煉油廠中使用的各類管殼式換熱器中浮頭式最多。1.shellandtubeheatexchangeroftheoverallstructureandcharacteristics1)FloatingheadheatexchangerOneendofthefloatingheadheatexchangerisfixed.Rigidlyconnectedtothehousing,theotherendofthetubeplateisactive,andtheshellisnotconnected.Thesideoftube-sheetisknownasthefloatinghead,floatingheadheatexchangertubebundlecanbeextractedfromtheshell,sothetubewalleasytoclean,thetubecanbefreeintheshelltelescopic,sonotemperaturestress;butthestructureiscomplex,Andifthemouthisnottightlysealedwillcausetwokindsoffluidmixing.Floatingheadheatexchangerforhotandcoldfluidtemperaturedifference(thegeneralcoldflowinletandheatflowtemperaturedifferenceofupto110℃),themedianeedtocleantheneedforcleaningoccasions.Intheuseofvarioustypesofshellandtubeheatexchangerinthefloatingheadtypeup.

總體結(jié)構(gòu)圖Overallstructure浮頭式換熱器和冷凝器，可采用內(nèi)導(dǎo)流或外導(dǎo)流結(jié)構(gòu)，管內(nèi)均可承受高壓。Floatingheadheatexchangerandcondenser,canbeusedwithinthediversionorexternaldiversionstructure,thetubecanwithstandhighpressure.內(nèi)導(dǎo)流換熱器結(jié)構(gòu)圖外導(dǎo)流換熱器結(jié)構(gòu)圖內(nèi)導(dǎo)流筒與外導(dǎo)流筒換熱器的區(qū)別Ⅰ、內(nèi)導(dǎo)流筒換熱器是在換熱器的殼程筒體內(nèi)設(shè)置了內(nèi)導(dǎo)流筒使換熱器的前或后端未加導(dǎo)流筒前難以利用換熱的換熱管得以充分利用，從而增大換熱器的有效換熱面積。Ⅱ、外導(dǎo)流式換熱器是在原換熱器的殼程筒體上增加一個(gè)放大筒節(jié)用以擴(kuò)散殼程流體，并使流體從換熱器殼程的兩端進(jìn)入殼程，從而避免了在換熱器布管時(shí)考慮布管弓形的高，而使增加了同規(guī)格上換熱器的布管數(shù)目并有效利用了換熱器前后端的換熱管從而增大了有效換熱面積。ThedifferencebetweentheinnerguidecylinderandtheexternalguidetubeheatexchangerⅠ,theinternalguidetubeheatexchangerisintheheatexchangershelltubebodyisprovidedwithintheinternalguidetubesothattheheatexchangerbeforeoraftertheendofthedrafttubeisnotdifficulttousetheheattransfertubetobesufficientUse,therebyincreasingtheeffectiveheattransferareaoftheheatexchanger.II,theexternalflow-typeheatexchangerisintheoriginalheatexchangershellsideofthecylindertoaddazoomtubesectiontodiffusetheshellprocessfluid,andthefluidfromtheheatexchangershellbothendsintotheshell,soastoavoidTheheatpipeintheheatpipewhenconsideringthehighangleofthetube,sothattheincreasewiththespecificationsoftheheatexchangeronthenumberofpipeandtheeffectiveuseoftheheatexchangerbeforeandaftertheendoftheheattransfertubetoincreasetheeffectiveheattransferarea.3）U型管式換熱器這種換熱器不同于固定管板式和浮頭式，只有一塊管板，換熱管作為U字形、兩端都固定在同一塊管板上；管板和殼體之間通過(guò)螺栓固定在一起。這種換熱器結(jié)構(gòu)簡(jiǎn)單、造價(jià)低，管束可在殼體內(nèi)自由伸縮，無(wú)溫差應(yīng)力，也可將管束抽出清洗且還省了一塊管板；但U形管管內(nèi)清洗困難且管子更換也不方便，由于U形彎管半徑不能太小，故與其他管殼式換熱器相比布管較少，結(jié)構(gòu)不夠緊湊。它適用于冷熱流體溫差較大、管內(nèi)走清潔不易結(jié)垢的高溫、高壓、腐蝕性較大的流體的場(chǎng)合。3)U-tubeheatexchangerThisheatexchangerisdifferentfromthefixedtubeplateandfloatingheadtype,onlyatubeplate,theheattransfertubeasU-shaped,bothendsarefixedonthesametubeplate;tubeplateandtheshellbetweentheboltstogether.Thiskindofheatexchangerhastheadvantagesofsimplestructure,lowcost,freeexpansionandcontractionofthetubeintheshell,notemperaturestress,andcanalsotakeoutthetubeandsavethetubeboard;buttheU-shapedpipeisdifficulttocleanandthepipeisnoteasytobereplaced,BecausetheU-shapedbendradiuscannotbetoosmall,socomparedwithothershellandtubeheatexchangertubeless,thestructureisnotcompactenough.Itissuitableforhotandcoldfluidtemperaturedifferencebetweenthetubetogocleanandeasytoscalehightemperature,highpressure,corrosivelargefluidoccasions.總體結(jié)構(gòu)圖4）釜式換熱器這種換熱器的殼體直徑一般為管束直徑的1.5～2.0倍，管束偏置于殼體的下方，液面淹沒(méi)管束，使管束上部形成一定的汽液分離空間。此換熱器多用來(lái)做蒸發(fā)器、分餾塔的重沸器或簡(jiǎn)單的廢熱鍋爐。根據(jù)需要，管束可以是固定管板型、浮頭型或U型管型。4)kettleheatexchangerThediameteroftheheatexchangershellisgenerally1.5to2.0timesthediameterofthebundle,thetubebundleisplacedundertheshell,theliquidsubmergedtubebundle,sothattheupperpartofthetubetoformacertainvapor-liquidseparationspace.Thisheatexchangerisusedforevaporators,reboilers,orsimplewasteheatboilers.Thetubebundlemaybeeitherafixedtubeplatetype,afloatingheadtypeoraUtypetubetypeasrequired.5）折流桿管殼式換熱器折流桿換熱器主要特點(diǎn)是：殼程不再設(shè)置折流板，而由折流桿組成的折流圈來(lái)代替折流板，既對(duì)管子起支撐作用，又對(duì)流體起擾動(dòng)作用，藉以達(dá)到強(qiáng)化傳熱的目的。折流桿管殼式換熱器的結(jié)構(gòu)特點(diǎn)：折流桿換熱器的核心部分是由一系列焊有折流桿的折流圈組成折流圈籠。圖5-1為折流圈的示意圖。圖5-2則為折流圈籠和管板的組裝圖。5)baffleshellandtubeheatexchanger

Themainfeaturesofthebaffleheatexchangerare:thebaffleplateisnolongersetupbaffle,andthebafflecomposedofbaffleinsteadofthebaffle,bothonthetubefromthesupportingrole,butalsotheroleofthefluidfromthedisturbanceToachievethepurposeofenhancedheattransfer.

Thestructuralcharacteristicsofthebaffle-typeheatexchangerare:Thecorepartofthebaffleheatexchangerconsistsofaseriesofbaffleswithabafflewithabaffle.Figure5-1isaschematicdiagramofthebaffle.Figure5-2showstheassemblyofthebafflecageandtubesheet.圖5-1折流圈的示意圖Schematicdiagramofthebaffle1—?dú)んwShell；2—折流圈Bafflering；3—折流桿Baffleroddbi、db0、d0—分別為折流圈的內(nèi)徑、外徑和殼體內(nèi)徑theinnerdiameterofthebaffle,theouterdiameterandtheinnerdiameteroftheshell圖5-2折流圈籠和管板的組裝圖BaffleringandcageassemblyofFIGtubesheet

從以上兩圖可以看出折流桿是均勻地焊在折流圈上，每一個(gè)折流圈側(cè)相隔一定的距離，按一定排列分別焊接在拉桿上，從而形成一個(gè)折流圈籠。折流桿可以是圓形、方形或長(zhǎng)方形。通常相鄰兩個(gè)折流圈的折流桿其方向是互相垂直的，即如果前一個(gè)折流圈的折流桿是垂直布置的，則后一個(gè)折流圈的折流桿就為水平布置。傳熱管穿過(guò)折流圈時(shí)可以有不同的情況，例如可以是兩根折流桿中間夾一根傳熱管子，也可以是兩根折流桿之間夾兩根傳熱管。而且前后折流圈的折流桿與傳熱管之間也可以有不同的組合情況。Fromtheabovetwofigurescanbeseenthatthebaffleisevenlyweldedtothebaffle,eachfuselagesideseparatedbyacertaindistance,accordingtoacertainarrangementwereweldedtotherod,thusformingabafflecage.Thebafflecanberound,squareorrectangular.Normallythebafflesoftheadjacenttwobafflesareorientedperpendiculartoeachother,thatis,ifthebaffleofthepreviousbaffleisverticallyarranged,thebaffleofthesubsequentbaffleisarrangedhorizontally.Whentheheattransfertubethroughthebafflecanhavedifferentcircumstances,forexample,canbetwobafflesinthemiddlefolderaheattransfertube,itcanbebetweenthetwobaffletwoheattransfertube.Andthefrontandrearbafflebetweenthebaffleandheattransfertubecanalsohaveadifferentcombination.

例如前面折流圈的折流桿是水平地支撐第1、3、5-----排傳熱管，隨后一個(gè)折流圈的折流桿則是垂直地支撐第2、4、6-----排傳熱管，然后依次交替布置。當(dāng)然也可以有其它的組合和布置方式，但不論何種布置方式都必須保證每根傳熱管能被四個(gè)折流圈的四根折流桿從四個(gè)方向?qū)⑵淅卫喂潭?。折流圈中的折流環(huán)可以用圓桿、方桿或方條制作，其內(nèi)徑等于管束的外徑，其外徑則等于殼體內(nèi)徑減去設(shè)計(jì)標(biāo)準(zhǔn)所規(guī)定的間隙。折流環(huán)的形式有桿式、板式和帶式三種。其中板式折流環(huán)的徑向厚度大于縱向厚度，而帶式折流環(huán)的徑向厚度小于縱向厚度。Forexample,thebaffleofthefrontbaffleishorizontallysupportingthefirst,third,fifth,andquinteredheattransfertubes,followedbyabafflebafflethatverticallysupportsthe2nd,----dischargeheatpipe,andthenarrangedinturn.Ofcourse,theremaybeothercombinationsandarrangements,butnomatterwhatarrangementmustensurethateachheattransfertubecanbefourbafflesfourbafflesfromfourdirectionstofirmlyfixed.Thebaffleinthebafflecanbemadeofaroundbar,squarebarorsquarebarwhoseinnerdiameterisequaltotheouterdiameterofthetubebundleanditsouterdiameterisequaltotheinnerdiameteroftheshellminustheclearancespecifiedbythedesignstandard.Theshapeofthebaffleisrod,plateandbelt.Whereintheradialthicknessoftheplatebaffleisgreaterthanthelongitudinalthicknessandtheradialthicknessofthebeltbaffleislessthanthelongitudinalthickness.優(yōu)點(diǎn)：①、不易發(fā)生誘導(dǎo)振動(dòng)損失；②、傳熱死區(qū)小，傳熱效率提高20%以上；③、壓降??；④、抗垢性能優(yōu)良；⑤、有強(qiáng)化冷凝的機(jī)理；⑥、適用于換熱器大型化，特別是在核電換熱器應(yīng)用；適用于冷凝、沸騰場(chǎng)合的換熱器；⑦、適用于壓縮機(jī)級(jí)間冷卻和煙氣預(yù)熱器。缺點(diǎn)：①、在低雷諾數(shù)Re＜6000（液相）、Re＜10000（氣相）熱效率較低；②、造價(jià)提高3~5%。Advantage:①,itisnoteasytoinducevibrationloss;②,heattransferdeadzoneissmall,heattransferefficiencyincreasedby20%ormore;③,pressuredropissmall;④,excellentanti-foulingperformance;⑤,thereisamechanismtostrengthenthecondensation;⑥,suitableforlarge-scaleheatexchanger,especiallyintheapplicationofnuclearheatexchanger;forcondensing,boilingheatexchanger;⑦,suitableforcompressorinter-stagecoolingandfluegaspreheater.Disadvantages:①,lowReynoldsnumberRe<6000(liquidphase),Re<10000(gasphase)thermalefficiencyislow;②,thecostincreasedby3to5%.6）雙弓形板換熱器Doublearchedplateheatexchanger結(jié)構(gòu)形式Structuretype雙弓形板換熱器與通常使用的單弓形板換熱器相比，僅在于折流板形狀的不同。雙弓形折流板由A、B兩種結(jié)構(gòu)組成。Doublearchedplateheatexchangercomparedwithasinglearcuateplateheatexchangerisgenerallyusedonlyindifferentbaffleshape.DoublesegmentalbafflebyA,Bcomposedoftwostructures.6）雙弓形板換熱器性能特點(diǎn)雙弓形板換熱器的管束由相鄰兩種折流板組成支撐件，流體呈順錯(cuò)流流動(dòng)，從而克服了普通單弓形板換熱器的殼程流體，在流動(dòng)中的180度轉(zhuǎn)彎所造成的死區(qū)、阻力大、易震動(dòng)等缺陷。在相同殼程壓力降下，雙弓形板換熱器殼程流體的流速一般可提高1.5倍以上，從而強(qiáng)化了傳熱。通過(guò)管束的阻力僅為單弓形扳換熱器的1/5～1/8，因此減少板間距和殼徑來(lái)提高流速是常用手段。6)DoublearchedplateheatexchangerCharacteristicsofitsperformanceDoublearchedplateheatexchangertubebundlefromthetwokindsofadjacentbaffleplatessupportmember,thefluidflowintheciscrossflowtoovercometheordinarysinglearcuateshell-sidefluidplateheatexchanger,the180-degreeturnintheflowofdeadzonecausedbytheresistance,vibration-proneandotherdefects.Pressuredropsinthesameshell,thearcuatedouble-flowplateheatexchangershellfluidisgenerallyincreasedmorethan1.5times,therebyenhancingheattransfer.Theresistancethroughthetubebundleisonly1/5to1/8ofthesingle-archedheatexchanger,soreducingtheplatespacingandtheshelldiametertoincreasetheflowrateisacommonmeans.7）螺旋折流板換熱器Helicalbaffleheatexchanger

螺旋折流板換熱器是管殼式換熱器的一種形式。每塊折流板占1/4的橫截面積，呈螺旋狀自進(jìn)口至出口方向逐一布置。折流板對(duì)換熱器中心線保持一定的傾斜角度，四塊折流板完成360。內(nèi)的旋轉(zhuǎn)，這樣在殼體內(nèi)形成連續(xù)的螺旋，使流體流動(dòng)接近柱塞流動(dòng)。

Helicalbaffleheatexchangersareaformofshellandtubeheatexchangers.Eachbaffleaccountedfor1/4ofthecross-sectionalarea,wasspiralfromtheimporttotheexportdirectiononebyonearrangement.Thebaffleplatemaintainsacertaininclinationangletothecenterlineoftheheatexchanger,andthefourbafflesarecompleted360.,Sothatacontinuousspiralisformedinthehousingsothatthefluidflowsclosetotheplunger.螺旋折流板換熱器基本原理及折流板形式螺旋折流板換熱器的提出基于這樣一種思想:通過(guò)改變殼側(cè)折流板的布置，使殼側(cè)流體呈連續(xù)的螺旋狀流動(dòng)。因此，理想的折流板布置應(yīng)該為連續(xù)的螺旋曲面。但是，螺旋曲面加工困難，而且換熱管與折流板的配合也較難實(shí)現(xiàn).考慮到加工上的方便，采用一系列的扇形平面板(稱之為螺旋折流板)替代曲面相間連接，在殼側(cè)形成近似螺旋面，使殼側(cè)流體產(chǎn)生近似連續(xù)螺旋狀流動(dòng)。一般來(lái)說(shuō)，出于加工方面的考慮，一個(gè)螺距取2～4塊折流板，相鄰折流板之間有連續(xù)搭接和交錯(cuò)搭接兩方式，按流道又可分為單螺旋和雙螺旋兩種結(jié)構(gòu)。Basicprincipleofspiralbaffleheatexchangerandbaffleplateform

Thespiralbaffleheatexchangerisbasedontheideathattheshellsidefluidflowsinacontinuousspiralbychangingthearrangementoftheshellsidebaffles.Therefore,theidealbafflearrangementshouldbeacontinuoushelicalsurface.However,thespiralsurfaceprocessingisdifficult,andtheheattransfertubeandthebafflewiththemoredifficulttoachieve.Withtheconvenienceofprocessing,usingaseriesoffan-shapedflatplate(calledthespiralbaffle)insteadofcurvedsurfaceconnected,Andanapproximatelyhelicalsurfaceisformedontheshellsidesothattheshellsidefluidproducesanapproximatelycontinuoushelicalflow.Ingeneral,forprocessingconsiderations,ascrewfromthe2to4baffles,adjacentbafflesbetweenthecontinuouslapandstaggeredoverlapbetweenthetwoways,accordingtotheflowchannelcanbedividedintosinglehelixandDoublehelixtwostructures.性能特點(diǎn)：與普通的弓形折流板換熱器相比，螺旋折流板換熱器有以下的性能改進(jìn)：①衡量換熱效果好壞的綜合效益系數(shù)(即傳熱速率與壓力降的比值)有較大的提高：

ABB公司以水一水為介質(zhì)，進(jìn)行普通弓形折流板和螺旋折流板的傳熱與壓力降實(shí)驗(yàn)對(duì)比，結(jié)果為：(a)螺旋折流板換熱器殼程傳熱系數(shù)約提高1.8倍；(b)壓力降減少約4.5倍。②殼程流體流動(dòng)狀態(tài)的改變：弓形折流板使殼程流體基本上處于橫穿管子的錯(cuò)流流動(dòng)，在90度轉(zhuǎn)彎處易有固體顆粒堆積和結(jié)垢產(chǎn)生。而螺旋折流板每塊折流板僅占1/4橫截面積，與中心線有一定角度的傾斜。Features:

Comparedwithconventionalsegmentalbaffleheatexchangers,spiralheatexchangerbafflehasthefollowingperformanceimprovements:

①measuretheheattransfereffectofgoodorbadcomprehensiveefficiencycoefficient(thatis,theratioofheattransferrateandpressuredrop)havegreatlyimproved:

Theresultsshowthat:(a)theheattransfercoefficientoftheshellofthehelicalbaffleheatexchangerisabout1.8(1),andtheheattransfercoefficientofthecoilisimprovedby1.8%Times;(b)thepressuredropbyabout4.5times.②changesinshellfluidflowstate:

Thebafflecausestheshell-sidefluidtobesubstantiallyinacross-flowflowacrossthetube,withsolidparticlesaccumulatingandfoulingat90°turns.Andthespiralbaffleeachbaffleonly1/4cross-sectionalarea,andthecenterlinehasacertainangleoftilt.折流板按一定的間距和不同方位相繼排列，使殼程流體呈旋轉(zhuǎn)柱塞流動(dòng)。這就消除了流動(dòng)死區(qū)，減少了固體顆粒堆積和結(jié)垢的生成。因?yàn)闆](méi)有橫穿管間的流動(dòng)，因此即使在較高的流速下也不易引起管子的振動(dòng)。③較低的壓力降允許流體提高流速，以使膜傳熱系數(shù)有較大的提高：因?yàn)闅こ虊毫祪H為普通弓形折流板的1/4-1/5，故可以允許介質(zhì)高速流過(guò)從而強(qiáng)化傳熱效果。在滿足管程需求的同時(shí)，可以盡量提高殼程流動(dòng)速度來(lái)提高膜傳熱系數(shù)。這樣，螺旋折流板換熱器需要精心設(shè)計(jì)，尋求適合的殼徑與管長(zhǎng)的比例，以達(dá)到提高總傳熱速率、減少換熱面積的目的。④對(duì)于限制殼程壓力降的設(shè)備，在利用原有殼徑的基礎(chǔ)上，螺旋折流板換熱器可以發(fā)揮自身優(yōu)勢(shì)。Thebaffleplateisarrangedinacertainpitchandindifferentorientationssothattheshellfluidflowsasarotatingplunger.Thiseliminatestheflowdeadzone,reducingtheaccumulationofsolidparticlesandtheformationoffouling.Sincethereisnoflowacrossthepipe,itisnoteasytocausethevibrationofthetubeevenatahigherflowrate.

③lowerpressuredropallowsthefluidtoincreasetheflowrate,sothatthemembraneheattransfercoefficienthasgreatlyimproved:

Becausetheshellpressuredropisonly1/4-1/5oftheordinarybowbaffle,itcanallowthemediumtoflowathighspeedtoenhancetheheattransfereffect.Inordertomeettheneedsofthepipelineatthesametime,youcantrytoimprovetheshellflowratetoimprovethemembraneheattransfercoefficient.Inthisway,thespiralbaffleheatexchangerneedstobecarefullydesignedtofindtheappropriateratioofshelldiametertopipelengthinordertoachievethepurposeofincreasingthetotalheattransferrateandreducingtheheattransferarea.④shellforlimitingpressuredropdevice,basedontheuseoftheoriginaldiameteroftheshell,thehelicalbaffleheatexchangercanplaytheirownadvantages.8）螺紋鎖緊環(huán)換熱器螺紋鎖緊環(huán)換熱器，其結(jié)構(gòu)主要由管箱、殼體、管束、管箱蓋、固定環(huán)、螺紋鎖緊環(huán)、壓緊環(huán)、密封裝置等零部件組成。一般設(shè)計(jì)壓力8~20MPa，設(shè)計(jì)溫度300~550℃，材料為2.25Cr-1Mo+347L或15CrMoR+321，是目前高壓換熱器設(shè)計(jì)難度高，制造難度大的換熱設(shè)備，螺紋鎖緊環(huán)換熱器結(jié)構(gòu)復(fù)雜，金屬耗量大，機(jī)加工配合件較多。Thebreechlockclosuretypeheatexchanger,itsstructuremainlybythetubebox,shell,tubebundle,tubeboxcover,fixedring,threadlockingring,pressingring,sealingdeviceandothercomponents.Thedesignpressureis8~20MPa,thedesigntemperatureis300~550℃,thematerialis2.25Cr-1Mo+347Lor15CrMoR+321,whichistheheattransferdevicewithhighdesignandhighdifficultyinmakinghighpressureheatexchanger.Heatexchangerstructureiscomplex,metalconsumption,machiningwithmorepieces.密封結(jié)構(gòu)——螺紋鎖緊環(huán)

Sealingstructure-Thebreechlockclosure

1-管箱殼體；2-固定螺栓；

3-固定螺栓；4-管箱蓋；

5-墊片壓板；6-固定環(huán)；

7-螺紋鎖緊環(huán)；8-壓緊環(huán)；

9-管程墊片；10-壓環(huán)；

11-內(nèi)法蘭；12-管程開(kāi)口接管；

13-密封裝置；14-管板；

15-傳熱管；16-殼體；

17-殼程開(kāi)口接管；18-殼程墊片；19-分程隔板；20-內(nèi)部固定螺栓；21-內(nèi)套筒密封結(jié)構(gòu)——螺紋鎖緊環(huán)

Sealingstructure-Thebreechlockclosure優(yōu)點(diǎn)：①、結(jié)構(gòu)上安全可靠；

②、耐高溫、高壓，溫度≤550℃，壓力≤20MPa；

③、密封性能好；

④、結(jié)構(gòu)獨(dú)特；

⑤、殼壁與管束壁溫差大，管束可自由伸縮，吸收膨脹差；

⑥、可拆卸、可清洗；

⑦、耐硫化氫腐蝕缺點(diǎn)：①、結(jié)構(gòu)復(fù)雜，設(shè)計(jì)繁瑣；

②、重量大，造價(jià)高；③、零部件較多，密封要求高；④、檢修、維修量大。advantage:①,thestructureissafeandreliable;②,hightemperature,highpressure,temperature≤550℃,pressure≤20MPa;③,goodsealingperformance;④,uniquestructure;⑤,shellwallandtubebundlewalltemperaturedifference,tubebundlecanbefreetostretch,absorptionexpansiondifference;⑥,removable,canbecleaned;⑦,resistancetohydrogensulfidecorrosionDisadvantages:①,complexstructure,cumbersomedesign;②,heavyweight,highcost;③,moreparts,highsealingrequirements;④,maintenance,maintenancevolume.9）Ω環(huán)高壓換熱器

Ω環(huán)高壓換熱器結(jié)構(gòu)由管箱、殼體、管束、Ω環(huán)等零部件組成，與普通U型管換熱器結(jié)構(gòu)相同，所不同的是密封墊片由Ω環(huán)代替。其原理是：工作狀態(tài)下介質(zhì)進(jìn)入Ω環(huán)中，由于小管子承壓高，故可承受壓力≤32MPa，由于采用0Cr18Ni11Ti耐溫可達(dá)550℃，由于操作過(guò)程中Ω環(huán)中介質(zhì)存在，故墊片比壓可選擇為零，減少了螺栓預(yù)緊載荷而使螺柱直徑減小，減少螺柱預(yù)緊時(shí)管板產(chǎn)生的載荷，減薄了管板的厚度，由此重量低，造價(jià)降低。9)Ωringhighpressureheatexchanger

Ωringhigh-pressureheatexchangerstructurefromthetubebox,shell,tubebundle,Ωringandothercomponents,andordinaryU-tubeheatexchangerstructureisthesame,thedifferenceisthegasketbytheΩringinstead.Theprincipleis:theworkingstateofthemediaintotheΩring,duetosmalltubepressureishigh,itcanwithstandthepressure≤32MPa,dueto0Cr18Ni11Titemperatureupto550℃,duetotheoperationprocessΩringmediumexists,Canbeselectedtozero,reducingtheboltpreloadloadleavingthestuddiameterdecreases,reducingthestudpreloadwhenthetubeplateload,thinningthethicknessofthetubeplate,whichislowweight,lowercost.優(yōu)點(diǎn)：①、結(jié)構(gòu)簡(jiǎn)單，設(shè)計(jì)簡(jiǎn)單；②、密封安全可靠；③、耐高溫、高壓，溫度≤550℃，壓力≤32MPa；④、結(jié)構(gòu)獨(dú)特；⑤、殼壁與管束壁溫差大，可吸收熱膨脹；⑥、拆卸方便，可清洗；⑦、采用流路分析法設(shè)計(jì)，傳熱效率提高20%以上；⑧、耐硫化氫腐蝕；⑨、重量可比螺紋鎖緊環(huán)降低23%，鍛件耗量少，造價(jià)節(jié)省21%；⑩、適用于8~32MPa壓力的加氫換熱器、合成氨換熱器、化肥裝置廢鍋換熱器、巨毒介質(zhì)換熱器以及絕對(duì)保證無(wú)泄露的場(chǎng)合。缺點(diǎn)：Ω環(huán)加工復(fù)雜，要求較高。

advantage:①,simplestructure,simpledesign;②,sealedsafeandreliable;③,hightemperature,highpressure,temperature≤550℃,pressure≤32MPa;④,uniquestructure;⑤,shellwallandtubewalltemperaturedifference,canabsorbthermalexpansion;,Easytodisassemble,canbecleaned;⑦,theuseofflowanalysismethoddesign,heattransferefficiencyincreasedby20%;⑧,resistancetohydrogensulfidecorrosion;⑨,weightcomparabletothethreadedlockingringby23%,forgingless,twentyone%;⑩,for8~32MPapressureofthehydrogenationheatexchanger,ammoniaheatexchanger,fertilizerplantwasteheaters,gianttoxicmediaheatexchangerandabsoluteguaranteenoleakageoftheoccasion.Disadvantages:Ωringprocessingcomplex,demanding.10）、板式換熱器板式換熱器其結(jié)構(gòu)由板片、壓緊板、膠墊、支架等零部件組成，是一種傳熱效率高，占地面積小，重量輕、結(jié)構(gòu)緊湊、維修、檢修、安裝較方便的換熱器。板片間采用膠墊密封或焊接。10),plateheatexchangerPlateheatexchangeritsstructurebytheplate,pressingplate,pads,stentsandothercomponents,isahighheattransferefficiency,smallfootprint,lightweight,compactstructure,maintenance,repair,installationmoreconvenientHeatExchanger.Platebetweentheuseofrubbersealorwelding.（1）、板式換熱器的優(yōu)點(diǎn)①傳熱系數(shù)高：板式換熱器具有較高的傳熱系數(shù)，一般約為管殼式換熱器的2-5倍。主要原因是流體在管殼式換熱器的殼程中流動(dòng)時(shí)存在著折流板-殼體、折流板-換熱管、管束-殼體之間的旁路，通過(guò)這些旁路的流體，沒(méi)有充分參與換熱。而板式換熱器，不存在旁路，而且板片的波紋能使流體在較小的流速下產(chǎn)生湍流，湍流效果明顯，(雷諾數(shù)約為200即為湍流)，故能獲得較高的傳熱系數(shù)。(1),theadvantagesofplateheatexchanger

①highheattransfercoefficient:plateheatexchangerhasahighheattransfercoefficient,generallyaboutshell-and-tubeheatexchanger2-5times.Themainreasonisthatthefluidflowsintheshellsideoftheshell-and-tubeheatexchangerwiththebaffle-shell,thebaffl