PERANCANGAN SISTEM/JARINGAN PEMISAH … Kuliah Section 2 1. Dasar‐dasar Penggunaan CHEMCAD/HYSYS...
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Transcript of PERANCANGAN SISTEM/JARINGAN PEMISAH … Kuliah Section 2 1. Dasar‐dasar Penggunaan CHEMCAD/HYSYS...
Perancangan Proses KimiaPerancangan Proses Kimia
PERANCANGAN PERANCANGAN SISTEM/JARINGAN PEMISAH & RECYCLE
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Rancangan Kuliah Section 2Rancangan Kuliah Section 21. Dasar‐dasar Penggunaan CHEMCAD/HYSYS2.Perancangan Sistem/jaringan Reaktor3.Tugas 1 dan Pembahasannya4 Perancangan Sistem/jaringan Separator & Recycle4.Perancangan Sistem/jaringan Separator & Recycle5.Tugas 2 dan Pembahasannya6.Perancangan Sistem/jaringan Pemanas6.Perancangan Sistem/jaringan Pemanas7.Tugas 3 ‐‐ Studi Kasus8.Ujian Section 2
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Heuristic of SeparationsHeuristic of SeparationsHeuristic 9: Separate liquid mixtures using distillation, 9 p q g ,stripping, enhanced (exctractive, azeotropic, reactive) distillation, liquid‐liquid extraction, crystallization, and/or absorptionabsorptionHeuristic 10: Attempt to condense or partially condense vapor mixtures with cooling water or a refrigerant. Then use Heuristic 9Heuristic 11: Separate vapor mixtures using partial condensation cryogenic distillation absorption condensation, cryogenic distillation, absorption, adsorption, membrane separation and/or desublimation
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Basic Configuration of Chemical ProcessBasic Configuration of Chemical Process
Liquid Liquid Feeds ProductsReactor System Separation
SystemFeeds Products
Liquid Recycle
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Separation of Vapor Reactor EffluentsEffluents
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The liquid separation system involves one or more of q p ythe following separators:
distillation and enhanced distillation, stripping stripping, liquid‐liquid extraction, and so on, with the unreacted chemicals recovered in a li id h d l d t th ti tiliquid phase and recycled to the reaction operation
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For reaction products in the vapor phase, ==> partially p p p p ycondense them by cooling with cooling water or a refrigerantCooling water can cool the reaction products typically to 35 Cooling water can cool the reaction products typically to 35 oCThe usual objective is to obtain a liquid phase, which is
i t t ith t i f i ti hi h easier to separate, without using refrigeration, which involves an expensive compression step.Unreacted chemicals are recycled to the reactor section yand vapor products are removedA vapor purge is added when necessary to remove inerts that concentrate in the vapor and are not readily separatedthat concentrate in the vapor and are not readily separated
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Separation of Vapor/Liquid Reactor Effl tEffluents
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HeuristicsHeuristicsCertain separation devices, i.e. membrane separators, are p pnot considered for the separation of liquidTo achieve a partial condensation, cooling water is utilized initially rather than compression and refrigerationinitially, rather than compression and refrigerationAn attempt is made to partially condense the vapor products, but no attempts is made to partially vaporize the li id d tliquid products
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General Flowsheet for a Separation PProcess
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Phase Separation of Reacton EffluentEffluent
Reactor effluent: homogeneous phase or heterogeneous hphaseHomogeneous phase ==> change Temperature and/or Pressure ==> to obtain partial separation of heterogeneous mixtureThree‐phase model considers the possibility that a vapor may also be present, together with two liquid phasesIf solids are present with one or two liquid phases, it is not possible to separate completely the solids from the liquid phase(s).pInstead, a centrifuge of filter is used to deliver a wet cake of solids
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Various Phase Separation DevicesVarious Phase‐Separation Devices
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Each exiting phase is either:g precycled to the reactorpurged from the systemsent to separate vapor liquid or slurry separation sent to separate vapor, liquid, or slurry separation systems
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Separate Separation Systems with Reactor‐system and Separation‐System Recyclesy p y y
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The effluents from these separation systems are:d hi h products, which are sent to storage
byproducts, which leave the processreactor‐system recycle streams, which are sent back to the reactorseparation‐system recycle streams, which are sent to one of the other separation systemsp y
Purges and byproducts are either additional valuable products, which are sent to storageF l b d hi h f l l Fuel byproducts, which are sent to a fuel supply or storage systemWaste stream, which are sent to waste treatment, Waste stream, which are sent to waste treatment, incineration, or landfill
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Example: hydrodealkylation of t l t btoluene to benzene
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Factors for Separation SelectionFactors for Separation SelectionPhase condition of the feedSeparation Factor (SF)
SF=y1 /x1/ y2 / x2=K1/K 2=α1,2Reason for Separation
purificationl f d i bl
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removal of undesirable componentsrecovery
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Sequencing of Ordinary Di till ti C lDistillation Columns
The relative volatility between the two selected key components for the separation in each column is >1.05The reboiler duty is not excessive. (low relative volatility ==> high duty reboiler)g y )The tower pressure does not cause the mixture to approach its critical temperatureThe overhead vapor can be at least partially condensed at the The overhead vapor can be at least partially condensed at the column pressure to provide reflux without excessive refrigeration requirementsThe bottoms temperature for the tower pressure is not so high The bottoms temperature for the tower pressure is not so high that chemical decomposition occursAzeotropes do not prevent the desired operationC l d i t l bl ti l l if ti i Column pressure drop is tolerable, particularly if operation is under vacuum
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Heuristics for Determining Favorable Sequence ==> Economic
Remove thermally unstable, corrosive, or chemically reactive y ycomponents early in the sequenceRemove final products one by one as distillatesS ti i t t l i th Sequence separation points to remove, early in the sequence, those components of greatest molar percentage in the feedSequence separation points in the order of decreasing relative q p p gvolatility so that the most difficult splits are made in the absence of other componentsSequence separation points to leave last those separations that Sequence separation points to leave last those separations that give the highest purity productsSequence separation points that favor near equimolar amounts f di ill d b i h lof distillate and bottoms in each column
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Configuration of Ternary Di till tiDistillation
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Phase Conditions of The Feed as Criterion
V f dVapor feed:Partial condensationDi till ti d i ditiDistillation under cryogenic conditionsGas absorptionG d tiGas adsorptionGas permeation with a membraned bli tidesublimation
Liquid Feed:FlashDistillationDistillationStrippingExctractive distillationA i di ill iAzeotropic distillationLiquid‐liquid extractionCrystallizationyLiquid adsorptionDialysis, reverse osmosis, ultrafiltration, etcSupercritical extractionSupercritical extraction
Slurries, wet cake, dry solidsFiltrationCentrifugation obtain a wet cakeThe separated into a vapor and a dry solid by drying
Example for Separation HeuristicsExample for Separation HeuristicsExample for Separation HeuristicsExample for Separation Heuristics
Relative Volatility DataRelative Volatility Data
Solution based on heuristics
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