Transcription of FLASH DRUM DESIGN - University of Oklahoma
1 FLASH DRUM DESIGN ChE 4253 - DESIGN IChE 4253 - DESIGN IVertical vessel Horizontal VesselFLASH DRUM DESIGN ChE 4253 - DESIGN IChE 4253 - DESIGN IInstalled UnitsFLASH DRUM DESIGN ChE 4253 - DESIGN IChE 4253 - DESIGN IDeflectors, and DiffusersFLASH DRUM DESIGN ChE 4253 - DESIGN IChE 4253 - DESIGN IDemistersFLASH DRUM DESIGN ChE 4253 - DESIGN IChE 4253 - DESIGN IControl SchemesFLASH DRUM DESIGN ChE 4253 - DESIGN IChE 4253 - DESIGN IDimensions to decideDhVhLhfFLASH DRUM DESIGN ChE 4253 - DESIGN IChE 4253 - DESIGN ICalculations to makeRatchford rice Equation (look for it!!)FLV=+iiiFzLx Vy=+iiiyKx=1iix= 1iiy= 1(1)1(1)iiiiiiizxVKFKzyVKF = + = + FLASH DRUM DESIGN ChE 4253 - DESIGN IChE 4253 - DESIGN IDimensions to decideD related to vapor velocity. hVrelated to vapor velocity.
2 HLrelated to level control hfrelated to floodingFLASH DRUM DESIGN ChE 4253 - DESIGN IChE 4253 - DESIGN ID related to vapor velocityWhere do these come from ? ()LVpermVvK =234ln (ln) (ln) (ln)lvlvlvlvAB F C Fd FE FKe++ + += = = = = LLlvVVWFW = FLASH DRUM DESIGN ChE 4253 - DESIGN IChE 4253 - DESIGN ID related to vapor ()LVpermVvK =6visd dFRv =34()3gLVdFgR = ()22314()23dragvisdraggDDV dLVdFFF F C R vgR + = = visFdragFgF212dragDV dFCAv =83dDgRKC=dragvisFF>> FLASH DRUM DESIGN ChE 4253 - DESIGN IChE 4253 - DESIGN IDimensional analysis for drag: Force is dependent on velocity, cross sectional area, density and viscosity. Two nondimensional numbers: Therefore Thus is a function of the particle Reynolds number. /RedvA =212dragDVdFCAv =(Re, ) 0bDfC=2(Re)12 DDcVdFCfAv ==DC83(Re)cdgRKf=(,,,,)0adragdVfF vA = FLASH DRUM DESIGN ChE 4253 - DESIGN IChE 4253 - DESIGN IBut, what should be used?
3 The criteria is that 5% of the liquid is entrained. Thus; were obtainedfitting experimental should take care of 4% (or less) of the 5%. LLlvVVWFW =44 Dperm VVDAv ==234ln(ln ) (ln ) (ln )lvlvlvlvAB F C Fd FE FKe++ + +=dRFLASH DRUM DESIGN ChE 4253 - DESIGN IChE 4253 - DESIGN IWho came up with this rule and why? What is so magic about 3 ft? (Room for demister?)Again, why 2ft? (Residence Time, Failure Analysis,Other Control issues?)or ~2 minutes residence : Nozzle size 136"2 Vhdiameter offeedline=+112"2fhdiameter offeedline=+VfLLhhh=++24poolLVhD = FLASH DRUM DESIGN ChE 4253 - DESIGN IChE 4253 - DESIGN IFinal considerationsIF 3 increase Vpool (Why???)IF 5 Use horizontal drum (Why?)
4 ??)Different DESIGN protocol: Why?LD<LD>
