Aspen-Plus推荐使用的物性计算方法.doc

做模拟的时候物性方法的选择是十分关键的，选择的十分正确关系着运行后的结果。是一个难点，高难点，而此内容与化工热力学关系十分紧密。 首先要明白什么是物性方法？比如我们做一个很简单的化工过程计算，一股100C,1atm的水-乙醇(1:1的摩尔比，1kmol/h）的物料经过一个换热器后冷却到了80C,0.9atm,问如分别下值是多少？1.入口物料的密度，汽相分率。2.换热器的负荷。3.出口物料的汽相分率，汽相密度，液相密，还可以问物料的粘度，逸度，活度，熵等等。以上的值怎么计算出来？好，我们来假设进出口的物料全是理想气体，完全符合理想气体的行为，则其密度可以使用PV=nRT计算出来。并且汽相分率全为1，即该物料是完全气体。由于理想气体的焓与压力无关，则换热器的负荷可以根据水和乙醇的定压热熔计算出来。在此例当中，描述理想气体行为的若干方程，比如涉及至少如下2个方程：1.pv=nRT，2.dH=CpdT. 这就是一种物性方法（aspen plus中称为ideal property method)。简单的说，物性方法就是计算物流物理性质的一套方程，一种物性方法包含了若干的物理化学计算公式。当然这例子选这种物性方法显然运行结果是错误的，举这个例子主要是让大家对物性方法有个概念。对于水-乙醇体系在此两种温度压力下，如果当作理想气体来处理，其误差是比较大的，尤其对于液相。按照理想气体处理的话，冷却后仍然为气体，不应当有液相出现。那么应该如何计算呢？想要准确的计算这一过程需要很多复杂的方程，而这些方程如果需要我们用户去一个个选择出来，则是一件相当麻烦的工作，并且很容易出错。好在模拟软件已经帮我做了这一步，这就是物性方法。对于本例，我们对汽相用了状态方程，srk,液相用了活度系数方程(nrtl,wilson,等等），在aspen plus中将此种方法叫做活度系数法。如果你选择nrtl方程，就称为nrtl方法，wilson方程就成为wilson物性方法(wilson property method)。在aspen plus中（或者化工热力学中）有两大类十分重要的物性方法，对于初学者而言，了解到此两类物性方法，基本上就可以开始着手模拟工作了。大体而言，根据液相混合物逸度的计算方法的不同，物性方法可以分为两大类：状态方程法和活度系数法。状态方程法使用状态方程来计算汽相及液相的逸度，而活度系数法使用状态方程计算汽相逸度，但是通过活度系数来计算液相的逸度。常见的状态方程有ideal,srk,pr,lk方程以及他们的一些改进方程.状态方程法就是基于此类状态方程来计算逸度，压缩因子，焓等等的物性方法。常见的活度系数方程有nrtl, wilson,uniquac等。活度系数法就是基于此类活度系数方程来计算液相逸度，液相焓等的物性方法。一般而言，对于常见的烃类如烷，烯，芳香族，无机气体如O2,N2等非（弱）极性的化合物，选用状态方程法；对于极性强的化合物，如水-醇，有机酸体系选用活度系数法。另外对于汽相聚合的物质，应选用特别的活度系数法，可以计算汽相聚合效应。对于无机电解质体系，选用elecnrtl物性方法。希望对大家有所帮助.Aspen Plus对不同应用领域，推荐使用的物性计算方法Recommended Property Methods for Different Applications 一、Oil and Gas Production 轻烃储存和运输过程Application (应用) Recommended Property Methods（推荐计算方法）Reservoir systemsPR-BM, RKS-BMPlatform separation PR-BM, RKS-BMTransportation of oil and gas by pipelinePR-BM, RKS-BM二、Refinery 炼油过程Application Recommended Property MethodsLow pressure applications(up to several atm)Vacuum tower, atmospheric crude towerBK10, CHAO-SEA, GRAYSONMedium pressure applications(up to several tens of atm)Coker main fractionator, FCC main fractionatorCHAO-SEA, GRAYSON, PENG-ROB, RK-SOAVE Hydrogen-rich applications, Reformer, HydrofinerGRAYSON, PENG-ROB, RK-SOAVE Lube oil unit, De-asphalting unitPENG-ROB, RK-SOAVE三、Gas Processing 气体加工Application Recommended Property MethodsHydrocarbon separations , Demethanizer, C3-splitterPR-BM, RKS-BM, PENG-ROB, RK-SOAVECryogenic gas processing , Air separationPR-BM, RKS-BM, PENG-ROB, RK-SOAVEGas dehydration with glycols PRWS, RKSWS, PRMHV2, RKSMHV2, PSRK, SR-POLARAcid gas absorption with Methanol (RECTISOL) NMP (PURISOL)PRWS, RKSWS, PRMHV2, RKSMHV2, PSRK, SR-POLARAcid gas absorption with Water Ammonia Amines Amines + methanol (AMISOL) Caustic Lime Hot carbonateELECNRTLClaus processPRWS, RKSWS, PRMHV2, RKSMHV2, PSRK, SR-POLAR 四、Petrochemicals 石油化工过程Application Recommended Property MethodsEthylene plant Primary fractionator CHAO-SEA, GRAYSONLight hydrocarbons Separation train Quench towerPENG-ROB, RK-SOAVEAromatics BTX extractionWILSON, NRTL, UNIQUAC and their ariancesSubstituted hydrocarbons VCM plant Acrylonitrile planPENG-ROB, RK-SOAVEEther production MTBE, ETBE, TAMEWILSON, NRTL, UNIQUAC and their variancesEthylbenzene and styrene plantsPENG-ROB, RK-SOAVE orWILSON, NRTL, UNIQUAC and their variancesTerephthalic acid WILSON, NRTL, UNIQUAC and their variances (with dimerization in acetic acid section)五、Chemicals 化工过程Application Recommended Property MethodsAzeotropic separations Alcohol separationWILSON, NRTL, UNIQUAC and their variancesCarboxylic acids Acetic acid plantWILS-HOC, NRTL-HOC, UNIQ-HOCPhenol plantWILSON, NRTL, UNIQUAC and their variancesLiquid phase reactions EsterificationWILSON, NRTL, UNIQUAC and their variancesAmmonia plantPENG-ROB, RK-SOAVEFluorochemicalsWILS-HFInorganic Chemicals Caustic Acids Phosphoric acid Sulphuric acid Nitric acid Hydrochloric acidELECNRTLHydrofluoric acidENRTL-HF 六、Coal Processing 煤加工Application Recommended Property MethodsSize reduction crushing, grindingSOLIDSSeparation and cleaning sieving,cyclones, precipitation, washingSOLIDSCombustionPR-BM, RKS-BM (combustion databank)Acid gas absorption with Methanol (RECTISOL) NMP (PURISOL)PRWS, RKSWS, PRMHV2, RKSMHV2, PSRK, SR-POLARAcid gas absorption with Water Ammonia Amines Amines + methanol (AMISOL) Caustic Lime Hot carbonate ELECNRTL七、Power Generation 发电过程Application Recommended Property MethodsCombustion Coal Oil PR-BM, RKS-BM (combustion databank) Steam cycles Compressors Turbines STEAMNBS, STEAM-TA八、Synthetic Fuel 合成燃料Application Recommended Property MethodsSynthesis gasPR-BM, RKS-BMCoal gasificationPR-BM, RKS-BMCoal liquefaction PR-BM, RKS-BM, BWR-LS九、Environmental 环境Application Recommended Property MethodsSolvent recoveryWILSON, NRTL, UNIQUAC and their variances(Substituted) hydrocarbon strippingWILSON, NRTL, UNIQUAC and their variancesAcid gas stripping from Methanol (RECTISOL) NMP (PURISOL) PRWS, RKSWS, PRMHV2, RKSMHV2, PSRK, SR-POLARAcid gas stripping from: Water Ammonia Amines Amines + methanol (AMISOL) Caustic Lime Hot carbonate ELECNRTLAcids Stripping NeutralizationELECNRTL十、Water and Steam 水和蒸汽Application Recommended Property MethodsSteam systems Coolant STEAMNBS, STEAM.TA 十一、Mineral and Metallurgical Processes 采矿和冶金Application Recommended Property MethodsMechanical processing: Crushing Grinding Sieving Washing SOLIDSHydrometallurgy Mineral leachingELECNRTLPyrometallurgy Smelter ConverterSOLIDSWILS-NTH; WILS-HOC; NRTL-NTH; NRTL-HOC; UNIQ-NTH; UNIQ-HOC; UNIF-HOCDimersDP?Y选择物性计算方法图示导引：NRTL； UNIQUAC；and their variancesELECNRTLPENG-ROB; RK-SOAVE; GRAYSON CHAO-SEAMedium pressureBK10; CHAO-SEA; GRAYSONLow pressureP?PENG-ROB; RK-SOAVE; PR-BM; LK-PLOCK; RKS-BMPseudocomponents & RealREALNonpolarR?Interaction parametersIs not available Interaction parameters available PSRK; RKSMHV2SR-POLAR; PRWS; RKSWS; PRMHV2; RKSMHV2Ij?WILSON; NRTL; UNIQUAC and their variances Si