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FCC沉降器内多相流动的数值模拟研究.docx

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FCC沉降器内多相流动的数值模拟研究 摘要 FCC气体分离装置中的沉降器是一个重要的组件，它用于分离液滴和颗粒物。得益于计算流体动力学的数值模拟方法，可以研究沉降器中多相流动的流场特性。本文使用ANSYSFluent软件对FCC沉降器内的多相流动进行了数值模拟，并探讨了不同工况下的流场分布、速度场以及液滴和颗粒物的分布情况。结果表明，在不同载荷下，液滴和颗粒物的沉降速度和分布情况与沉降器的结构密切相关。本文的研究结果对于优化FCC气体分离装置的设计具有重要的意义。 关键词：FCC沉降器；计算流体动力学；多相流动；液滴；颗粒物 Introduction Fluidcatalyticcracking(FCC)isanimportantprocessinthepetrochemicalindustry,whichhasbeenwidelyusedtoconvertheavyhydrocarbonsintolighterones.TheFCCprocessinvolvesaseriesofcomplexphysicalandchemicalreactions,whichoftenproducealargeamountofdropletsandparticles.Toensurethesmoothoperationoftheprocessandtheproductquality,itisnecessarytoremovethesedropletsandparticlesfromthegasstreamefficiently.TheFCCdropletseparatorisanessentialcomponentoftheFCCunit,whichisusedtoseparatedropletsandparticlesfromthegasstream. Thedropletseparatorisusuallyacylindricalvesselwithaseriesofbafflesinstalledinit.Thebafflesaredesignedtochangethedirectionofthegasflowandcausetheparticlestosettleoutbygravity.Duetothecomplexityoftheflowinthedropletseparator,itisdifficulttostudyitexperimentally.Therefore,numericalsimulationisapowerfultooltounderstandthebehaviorofdifferentphasesinthedropletseparator. Inthisstudy,weusetheANSYSFluentsoftwaretosimulatethemultiphaseflowinanFCCdropletseparator.Thegoalofourstudyistoinvestigatetheflowpattern,velocitydistribution,anddropletandparticledistributionunderdifferentoperatingconditions. Methodology Thedropletseparatormodeledinthisstudyisacylindricalvesselwithadiameterof2.5mandaheightof4m.Thegasinletislocatedatthetopofthevessel,andthegasoutletislocatedatthebottom.ThegeometryofthedropletseparatorisshowninFigure1. Tosimulatetheflowinthedropletseparator,weusetheEulerian-EulerianapproachinANSYSFluent.Inthisapproach,thegasandliquidphasesaretreatedasseparatecontinua,andtheirinteractionsaremodeledbyinterphasemomentumtransfer.Theflowequationsgoverningthetwo-phaseflowaresolvedusingthefinitevolumemethod. Tomodelthegas-solidflow,thediscretephasemodel(DPM)isused.TheDPMisbasedontheLagrangianapproach,wherethepart