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REQUIRE "flash.a4l"; |
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REQUIRE "simpleUnits.AWW.a4c"; |
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|
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(* |
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|
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------------ |
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| | |
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-------------------------->|U4: splitter|---> bleed |
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| | | |
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| ------------ |
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| ^ |
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V | |
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----------- ----------- ------------ |
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| | | | | | |
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--->|U1: mixer |--->|U2: reactor|--->|U3: flash | |
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| | | | | | |
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----------- ----------- ------------ |
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2C2H6 -->C4H12 | |
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| |
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---------> product |
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|
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*) |
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|
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|
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MODEL simpleFS; |
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(* this demo is a reproduction of simpleFS using |
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the models in simpleUnits along with a rigorous |
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flash for the separation step *) |
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|
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(* Set up the thermo calculations *) |
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|
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compsC3, compsAll IS_A set OF symbol_constant; |
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compsC3 :== ['propylene', 'propane']; |
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compsAll :== ['propylene', 'propane', '2_hexene_cis']; |
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|
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cdC3 IS_A components_data(compsC3, 'propane'); |
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cdAll IS_A components_data(compsAll, 'propane'); |
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|
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pdV IS_A phases_data('V','Pitzer_vapor_mixture','none','none'); |
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pdL IS_A phases_data('L', 'none', 'UNIFAC_liquid_mixture','none'); |
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pdVL IS_A phases_data('VL','Pitzer_vapor_mixture', |
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'UNIFAC_liquid_mixture','none'); |
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|
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equil IS_A boolean; |
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|
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(* define feed streams *) |
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S01C3Feed IS_A stream(cdC3, pdV, equil); |
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|
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(* define units and their output streams *) |
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|
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(* U1: feed mixer and heater *) |
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Qmix IS_A energy_rate; |
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S12reactFeed IS_A stream(cdAll, pdVL, equil); |
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U1feedMixer IS_A unitTwoInOneOut(Qmix, S01C3Feed, S51recycle, S12reactFeed); |
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|
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(* U2: reactor *) |
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Qreactor IS_A energy_rate; |
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S23reactProd IS_A stream(cdAll, pdV, equil); |
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U2reactor IS_A unitOneInOneOut(Qreactor, S12reactFeed, S23reactProd); |
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conv IS_A fraction; |
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U2reactor.product.f['propylene'] = (1-conv)*U2reactor.feed.f['propylene']; |
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|
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(* U3: flash *) |
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Qflash IS_A energy_rate; |
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S34flashV IS_A stream(cdAll, pdV, equil); |
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S30flashL IS_A stream(cdAll, pdL, equil); |
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U3flash IS_A vapor_liquid_flash( |
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Qflash, equil, S23reactProd, S34flashV, S30flashL); |
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|
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(* U4: splitter *) |
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Qsplitter IS_A energy_rate; |
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S40bleed IS_A stream(cdAll, pdV, equil); |
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S45compFeed IS_A stream(cdAll, pdV, equil); |
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U4splitter IS_A unitOneInTwoOut(Qsplitter, S34flashV, S45compFeed, S40bleed); |
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(* merge all splits for simple stream splitter *) |
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splitRecycle IS_A fraction; |
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splitRecycle, U4splitter.split[compsAll] ARE_THE_SAME; |
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|
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(* U5: compressor *) |
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Qcomp IS_A energy_rate; |
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effU5 IS_A fraction; |
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compRatioU5 IS_A factor; |
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S51recycle IS_A stream(cdAll, pdV, equil); |
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U5compressor IS_A simpleCompressor(Qcomp, compRatioU5, effU5, S45compFeed, S51recycle); |
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|
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(* recycle pressure should be that of the feed *) |
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U5compressor.product.P = U1feedMixer.feed1.P; |
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|
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|
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(* various objectives we can optimize *) |
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MaxHexeneProd: MAXIMIZE S30flashL.f['2_hexene_cis']; |
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|
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METHODS |
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|
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METHOD default_self; |
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RUN U1feedMixer.default_self; |
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RUN U2reactor.default_self; |
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RUN U3flash.default_self; |
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RUN U4splitter.default_self; |
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RUN U5compressor.default_self; |
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END default_self; |
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|
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METHOD values; |
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equil := FALSE; |
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|
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(* feed streams *) |
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S01C3Feed.f['propylene'] := 0.98 {mol/s}; |
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S01C3Feed.f['propane'] := 0.02 {mol/s}; |
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S01C3Feed.T := 423.15 {K}; (* 150 degC *) |
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S01C3Feed.P := 20 {bar}; |
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|
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(* U1 feed mixer *) |
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(* set a pressure drop for the unit *) |
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U1feedMixer.delP1 := -5.0 {psia}; |
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|
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(* U2 reactor *) |
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U2reactor.delP := -5.0 {psia}; |
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U2reactor.stoichCoef['propylene'] := -2; |
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U2reactor.stoichCoef['2_hexene_cis'] := 1; |
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conv := 0.8; |
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|
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(* U3 flash *) |
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U3flash.liqout.P := 10 {bar}; |
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U3flash.liqout.T := 400 {K}; |
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U3flash.alpha['propylene'] := 7; |
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U3flash.alpha['propane'] := 8; |
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U3flash.alpha['2_hexene_cis'] := 1; |
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U3flash.state.phase_fraction['vapor'] := 0.5; |
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|
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(* U4 splitter *) |
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splitRecycle := 0.98; |
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|
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(* U5 compressor *) |
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U5compressor.efficiency := 0.95; |
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END values; |
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|
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METHOD specify; |
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(* Each unit runs the specify method for each of its |
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streams. It then releases the fixed flags for |
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the component flows, T and P of its product |
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streams. |
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|
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Only the recycle stream is overspecified |
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after running the unit specify methods if |
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we run them in the reverse order *) |
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|
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RUN U5compressor.specify; |
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RUN U4splitter.specify; |
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RUN U3flash.specify; |
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RUN U2reactor.specify; |
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RUN U1feedMixer.specify; |
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|
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(* release specs set by splitter for flash vapor *) |
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S34flashV.f[compsAll].fixed := FALSE; |
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|
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(* release specs for recycle stream *) |
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S51recycle.f[compsAll].fixed := FALSE; |
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S51recycle.T.fixed := FALSE; |
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S51recycle.P.fixed := FALSE; |
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|
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(* U1: feed mixer *) |
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(* fix product temperature of feed mixer *) |
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U1feedMixer.delT1.fixed := TRUE; |
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U1feedMixer.Qin.fixed := FALSE; |
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|
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(* U2: reactor *) |
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(* fix conversion *) |
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conv.fixed := TRUE; |
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U2reactor.turnover.fixed := FALSE; |
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(* product temperature is same as that of feed *) |
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U2reactor.delT.fixed := TRUE; |
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U2reactor.Qin.fixed := FALSE; |
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|
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(* U3: flash *) |
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(* flash P and vapor fraction already fixed *) |
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|
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(* U4: splitter *) |
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|
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(* U5: compressor *) |
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U5compressor.compressionRatio.fixed := FALSE; |
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|
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END specify; |
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|
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END simpleFS; |
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