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1、FluidPhaseEquilibria349(2013)37–55ContentslistsavailableatSciVerseScienceDirectFluidPhaseEquilibriajournalhomepage:∗SchoolofChemicalEngineering,OklahomaStateUniversity,Stillwater,OK74078,UnitedStatesarticleinfoArticlehistory:Received18January2013Receivedinrevisedform3April2013Accepted5April2013Availableonline15April2013Keywords:VolumetranslationPeng-RobinsonequationofstateSaturatedliquiddensitiesSingle-phasedensitiesBubblepointBinarymixturesAsymmetricmixturesVapor–liquidequilibriaabstractTwo-pa。
2、rametercubicequationsofstate(CEOS)arewidelyusedinprocessengineeringcalculations.However,inaccurateliquiddensitypredictionsremainasignificantdeficiencyintheseequations.Toremedythisproblem,avolumetranslationoftheCEOSisfrequentlyemployed.Inarecentwork,wepresentedavolume-translatedPeng-Robinsonequationofstate(VTPREOS)thatiscapableofprovidingaccuratedensitypredictionsforbothsaturated-andsingle-phaseregionsofpurefluidsathighpressures.Inthecurrentwork,wepresentanextensionofthatapproach,employingconvention。
3、almixingrules,topredictdensitiesofliquidmixturesoverlargerangesofpressureandtemperature.Forthispurpose,twodatabaseswerecompiledforvapor–liquidequilibriumandliquiddensitymeasurementsof73binarysystemscomposedofdiversechemicalspecies.Themolecularspeciesinthedatabasesrangedwidelyintermsofmolecularsize,shape,asymmetryandpolarityand,thus,werewellsuitedtotesttheefficacyofourapproach.Overall,thedatabasescontainedmorethan5000datapointsforvapor–liquidequilibriummeasurementsandover13,000datapointsforliquidd。
4、ensitymeasurementsofmixtures.ResultsindicatethatextensionoftheVTPREOStoliquidmixturesiscapableofprovidingreliabledensitypredictionsfordiversebinarymixturesoverlargerangesofpressure.TheVTPREOSpredictionsofmixtureliquiddensitiesyielderrorsthatarethreetofivetimeslowerthanthecorrespondingpredictionsfromtheuntranslatedPeng-Robinsonequationofstate(PREOS).Specifically,theoverallpercentageaverageabsolutedeviations(%AAD)fromtheVTPREOSvariedfrom1.5to3forbinarymixtures.Thisrepresentsasubstantialimprovementre。
5、lativetotheuntranslatedPREOS,forwhicherrorsrangedfrom2to15%AAD.©2013ElsevierB.V.Allrightsreserved.1.IntroductionReliable,accuratethermodynamicmodelsarenecessaryfordesignofchemicalprocessesandforreservoirsimulationsinthepetroleumandnaturalgasindustry.Duetotheirinherentsimplic-ityandcomputationalefficiency,cubicequationsofstate(CEOS)suchastheSoave-Redlich-Kwong(SRK)[1]andPeng-Robinson(PR)equationsofstate[2]arewidelyusedinprocessdesignandreservoirsimulations.However,awell-knowndeficiencyinthetwo-para。
6、metercubicequationsofstateistheirinaccurateliq-uiddensitypredictions.Toaddressthisproblem,atranslationinthecalculatedvolumeisfrequentlyemployed.BeginningwiththeworksofMartin[3]andPenelouxetal.[4],severalvolume-translationapproacheshavebeenproposedintheliterature.Theserangefromaconstantcorrectiontermtomorecomplexformsthatarebothtemperatureanddensity-dependent[3–16].Inarecentwork[17],wepresentedanewvolume-translationfunction∗Correspondingauthor.Tel.:+14057445280;fax:+14057446338.E-mailaddress:gase。
7、m@okstate.edu(K.A.M.Gasem).basedonthedimensionless-distanceapproachofMathiasetal.[13]andChouandPrausnitz[7].Thenewvolume-translationfunctioncontainsonlyonefluid-specificparameter,andwehavegener-alizedthisparameterintermsofmolecularpropertiessuchascriticalcompressibilityfactor,acentricfactoranddipolemoment[17].Thenewvolume-translatedPeng-Robinsonequationofstate(VTPREOS)providesaccuratepredictionsofliquiddensitiesinboththesaturated-andsingle-phaseregionsforpurefluidsofdiverseclassesofmolecules.Inaddi。
8、tion,theVTPREOSdoesnotleadtother-modynamicinconsistencies,suchasisothermcross-oversinthecompressedliquidregionathighpressures,whichwereobservedinsomeofthetemperature-dependentmethodsintheliterature[18].Animportantaspectofvolume-translationmethodsistheirextensiontomixtures.ApartfromPeneloux’swork[4],onlyafewvolume-translationmethodsintheliteraturehavebeenextendedtomixtures.TsaiandChen[14]andLinandDuan[11]extendedtheirvolume-translationmethodstomixtures,butonlyforatmosphericpressureconditions.Sinc。
9、emostvolume-translationmethodsavailableintheliteraturehavebeendevelopedandtestedonlyforpurefluids,aneedexistsforareliable0378-3812/$–seefrontmatter©2013ElsevierB.V.Allrightsreserved.fluid.2013.04.00238A.M.Abudouretal./FluidPhaseEquilibria349(2013)37–55volume-translationmethodthatcanprovideaccuratepredictionsofsaturated-andsingle-phaseliquiddensitiesformixtures.There-fore,inthiswork,weextendtheVTPREOSfromourpreviouswork[17]topredictdensitiesofdiversemixturesoverlargerangesofpressureandtemperature.A。
10、sisshownherein,theVTPREOSappearscapableofprovidingaccuratepredictionsofliquiddensi-tiesforbinarymixturescomprisedofdiversemolecularspecies.Asdiscussedelsewhere[7],asuccessfulapplicationofvol-umetranslationtomixturesrequiresasatisfactorydescriptionofphaseequilibriaofthemixtures.Thus,inthisw。
本文标题:Volume-translated Peng-Robinson equation of state
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