板式精馏塔的操作文献原文及翻译.docx

板式精馏塔的操作文献原文及翻译.docx

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板式精馏塔的操作文献原文及翻译

板式精馏塔的操作_文献原文及翻译

Operationofplaterectificationtower

WUChang-xiang

HarbinGasificationPlant,Harbin154864,China

　　Abstract:

Theinfluencingfactors,abnoimalphenomenonandrectificationprocesswereanalyzedtodirectactualoperation

　　Keywords:

rectificationtower,recification,reboiler,operation

　　Distillationcolumnisamulti-stagepartialvaporizationandpartialcondensationaccordingtothedifferentcomponentsinthemixturevolatilityineachfloortowerboardtoachievetheseparationofamixtureofvariouscomponentsofthetowergas-liquidcontactdevice,alsoknownasdistillation.Aplatecolumnandpackedcolumntypes.Accordingtomodeofoperationaredividedintocontinuousdistillationandbatchdistillation.Steamfromthebottomofthecolumnentry,andthedeclineinliquidcountercurrentcontactwiththetwoincontact,thedropinthevolatileliquidlowboilingpointcomponentsiscontinuouslytransferredtothesteam.Thedifficultyofsteamvolatilehighboilingcomponentcontinuedtodeclineinthetransferofliquid,steamthecloserthetopofthetower,thehighertheconcentrationofitsvolatilecomponents,whilethedeclineintheclosertowerbottomliquid,itshardtobemorevolatilecomponentsrichset,toachievecomponentseparation.Steamrisingfromthetopofthetowerintothecondenser,theliquidpartofthecondensateasrefluxliquidtoreturnintothedistillationtower,therestisremovedasdistillate.Towerbottomoutflowofliquid,someofwhichintothereboiler,thermalevaporation,thesteambacktotower,andtheotherpartoftheliquidasresiduarelease.

　　Comparedwithotherchemicalunitoperations,distillationunit,althoughrelativelysimple,singleproductionrunthatoftenappearinavarietyofproblemsaffectingtheoperationofthedistillationunit,leadingtotowertoporbottomofproductfailure,severeconstraintsofproductionequipmenttheoperationresultinginproductloss.

1.Regularchangesinprocessconditionsofdistillationcolumn

1.1Reboilertemperature

　　　Underthesameoperatingpressure,raisingthetemperatureofthereboiler,thevolatilecomponentsinthetowerliquidtoreduce,atthesametime,therisingvaporvelocityincreases,andhelptoimprovetheefficiencyofmasstransfer.Ifproductsfromthetopofthetower,thetowerreactordischargeofdifficultvolatilesvolatilecomponentstoreduceandreducelosses.Ifthetowerreactoreffluentsfortheproduct,itcanimproveproductqualitytowerdischargeofvolatilecomponentsentraineddifficultnolatilecomponentsincreased,therebyincreasingthelosses.Inbalancedoperation,thereactortemperatureissuddenlyincreased,andittoolatetoadjustthepressureandtemperaturewillinevitablyleadtothereboilerfluidissteam-air,thepressureincreased.Atthistime,thetowergas,liquidcompositionchanges,therestructuringwerelikelytobesteamedtothetopofthetower,sothatthefailureoftopproduct.

1.2Operatingpressure

　　　Inthecaseofcertainoperatingtemperature,increasingtheoperatingpressurecanincreasetheproductivecapacityofthetower,sothatstableoperation,butthecontentofvolatilegroupinthetowerreactorproducts.Indistillation,oftenprovidesfortheadjustmentrangeoftheoperatingpressure.Whenthefalloutoftheoperatingpressurebyextmrnalfactors,weredestroyed,thenormaloperationofthetowerwillbecompletelydestroyed.

1.3Feedingtemperature

1.3.1Condensatefeed,thefeedtemperatureislowerthanthetemperatureofthefeedingboard,andaddedifallthematerialintothestrippersegment,strippingsegmentloadincreases,thereboilerconsumptionincreaseintheamountofsteam,andthetopofthetowerisdifficultvolatilegroupwerelower.

1.3.2Saturatedsteamfeed,thefeedmaterialtemperatureishigherthanthetemperatureoffeedboard,allthematerialofthefeedintotherectifyingsectionandstrippingsectionoftheloadreduction,andincreasedloadoftherectifyingsection,makethetopproductqualityreduce.

1.4Feedingquantityandcompositionchanges

　　　Changesinthefeedstockofadirectimpactonthechangeoftheamountofsteam,thelatterincreasewillproduceentrained,evenflooding.Thefeedstockistoolow,theoperationisnotgoodtomaintainthebalanceofthetower,thesteamvelocitydecreases,theplateispronetoleakage,therectificationefficiencyislow.Inthelow-loadoperation,maybeappropriatetoincreasetherefluxratio,thetoweroperatinginaloadlowerlimitabovenormalandstableoperationinordertomaintainthetower.Feedingcomponentofthechangesdirectlyaffecttheproductquality.Increasedrestructuringconcentrationincreaseintherectifyingsectionloadseparationisnotgood,theresultsofrestructuringwerebroughttothetopoftower,causingthetopofthetowerofinferiorquality.Productfromthereboiler,thetopofthetowerlossesincrease.Iftheconcentrationofthevolatilegroupinthefeedinggroupwereincreased,andthestrippingsectionoftheloadincreases,maybepoorduetotheseparationcausedbythetowerreactorproductsofinferiorquality,whichentrainedvolatilecomponentsincreased.Feedingrestructuringconcentrationincreased,thefeedingmouthmovedownandviceversa,thenmoveup.Thesametime,operatingtemperature,backflowandoperatingpressuremustbeadjustedaccordinglyinordertoensurethestabilityofthedistillationoperation.

　　　Distillation,increasingtherefluxratio,canimprovethequalityoftheproduct,buttherefluxratioistoolarge,theinnerloopofthetowerincreased,increasingenergyconsumption.Reductionoftherefluxratio,thetowergas-liquidcontactisnotgood,thebalancetodamagedandthereforethemasstransferefficiencydecreased.Thesametime,theoperatingpressuredrop,difficultvolatilecomponentseasilybroughttothetopofthetower,resultinginasubstandardproduct.

2Anomaliesinthedistillationcolumnduringoperation

2.1Platecapacity

　　　Rectifyingsectiontraydowncomeroverflowliquidtransportation,however,thatthetowerupperpartofthebeginningofflooding,aphenomenonknownasdowncomerobstructionorliquidflooding.Itscausesistoblocktheliquidleavingthetowerboardlevelriseinthedowncomerplatebetweenmistentrainedexcessiveleavingthetrayefficiencytoreduceentrainmentofthisphenomenonisknownastheexcessivefogorsteamflooding,thereasonistherelativeinthegaswhilethetowerboardbubblingareaistoosmall.

2.2Platefouling

　　　Sedimentcumulativetotheboardofboardofthetowerisanimportantissue,traysofdirtwilltowerprematurefloodingwillreducetheplateefficiency.Platescalingphenomenon:

1Therefluxratioisnothighonliquidpan;2Thepressuredropincreasebetweenthetray;3Increasetherefluxratioonthebottomofthecolumntemperature,floworreboilerloaddoesnothaveanyimpact,iftherefluxratiototheheatbalanceandmaterialbalanceof20%to30%,whilethetowerdidnotchangesignificantly,thenthetowermustbecompletelyfullofliquid.Theamountofreturningtowerdirectstreamgaspipelinethroughthetopofthetowerbacktotherefluxtank.

2.3Slugflowsintheriser

　　　Slugflowintheriserisadistillationcolumnrunningunstable,maybecausedduetoanunstablegas-liquidmixtureflowintheverticalpipeline.Refluxtankiselevatedattheofthecondenserbythecondenserdischargelogisticsisthatpartofthepipelinebetweenthegas-liquidtwo-phasemixture,thecondenserandrefluxtankiscalledtheriser.Generatealiquidcolumnintheriserflowrateistoolowwillresultintwo-phaseseparation,thedistillationcolumntoproduceabackpressure,thisliquidcolumnintermittentlybeintroducedaftertheriser,backpressurewillweaken,thentherisergraduallybeingfilledwithliquid,suchslugflowwillcausethetowerpressureperiodicpulseofchange.

　　　Abnormalfactorscausedistillationcolumnplatewaswashedaway,condensercorrosion,cloggedcaondenser,notcondensablegasinfluencecondenser.

3.Reboiler

　　　Reboilerinthedistillationcolumnoccupiesaveryimportantposition,itusedtobebottomafterthevaporizationoftheliquidpartofthebacktothedistillationcolumn,twophasesofthetowergas-liquidcontactandmasstransfertoproceed.Whichusedtheverticalthermalsiphonreboiler,whichisaverticalplacementoftheshellandtubeheatexchanger.Partialvaporizationofliquidinthebottom-uptubepassesthroughtheheatexchanger,heatingtheheatcarrierintheshell.Verticalthermalsiphonreboilerfeatures:

1cycledrivingforce:

thedensityofthereactorliquidandtheheatexchangertubegas-liquidmixture;2compact,smallfootprint,highheattransfercoefficient;3oftheshellcannotbemechanicallycleaned,notsuitableforhightowerreactor,heattransfermediumviscosity,ordirty;4providethespaceandbufferzonesofthegas-liquidseparator.

　　　Factorsthatdeterminethedistillationcolumncapacityrestricted,findthereboilerfailureisthemostlaborious,thedistillationcolumnbysteamreboiler.

　　　1gas-barrierdrainvalvefailure;2steamcondensatecollectedindoorpressureistoolarge;3thecondensateliquidsealfailure.

　　　Hydrophobicfailurecausedbyhydrophobicfailurefactors:

3.1Thermosiphonrebilerfailure

　　　Reboilerliquidinletpipeandoutletpipecoldliquidmixtureexistsbetweenthedensitydifferenceisthedensitydifferencedrivingtheprocessofprocessingliquidflowthroughthereboiler.Whentowerhumoralbitelevatedtothereboilerbacktotheliquidnozzleheight,siphoncirculationwillbeimpeded.Thecirculationratereductionwillresultinthereductionofheattransfer,thusthecoverbacktothefluidnozzleisclearlyanimportantreasonforfluctuationsinthereboilerduties.

3.2Non-condensable