Aspen-Plus推荐使用的物性计算方法

1、Aspen-Plus推荐使用的物性计 算方法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方我们做一个 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,嫡等等.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

2、的行为,那么其密度可以使用 PV=nR耐算出来.并且汽相分率全为1,即该物料 是完全气体.由于理想气体的给与压力无关,那么换 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假设干方程, 比方涉及至少如下 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 假设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

3、果当作理想气体来处理,其误 差是比拟大的,尤其对于液相.根据理想气体处理 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,那么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 met

4、hod .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,根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良方程.状态方程法就是基于此类状态方程 来计算逸度,压缩因子,焰等等的物性方法.常见 的活度系数方程有nrtl, wilson,uniquac 等.活 度系数法

5、就是基于此类活度系数方程来计算液相 逸度,液相燃等的物性方法.一般而言,对于常见的烧类如烷,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 轻燃储存和运输过

6、程Application 应用Recommended Property Methods推荐计算方法Reservoir systemsPR-BM, RKS-BMPlatform separationPR-BM, RKS-BMTransportation of oil and gas by pipelinePR-BM, RKS-BM二、Refinery炼油过程ApplicationRecommended Property MethodsLow pressure applications(up to several atm)Vacuum tower, atmospheric crude towerB

7、K10, CHAO-SEA, GRAYSONMedium pressure applications(up to several tens of atm)Coker main fractionator, FCC main fractionatorCHAO-SEA, GRAYSON, PENG-ROB, RK-SOAVEHydrogen-rich applications, Reformer, HydrofinerGRAYSON, PENG-ROB, RK-SOAVELube oil unit, De-asphalting unitPENG-ROB, RK-SOAVE三、Gas Processi

8、ng 气体加工ApplicationRecommended 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 glycolsPRWS, RKSWS, PRMHV2, RKSMHV2,PSRK, SR-POLARAcid gas absorption with M

9、ethanol (RECTISOL) NMP (PURISOL)PRWS, RKSWS, PRMHV2, RKSMHV2,PSRK, SR-POLARAcid gas absorption withWaterAmmoniaAminesAmines + methanol (AMISOL)CausticLimeHot carbonateELECNRTLClaus processPRWS, RKSWS, PRMHV2, RKSMHV2,PSRK, SR-POLAR四、Petrochemicals石油化工过程ApplicationRecommended Property MethodsEthylene

10、 plantPrimary fractionatorCHAO-SEA, GRAYSONLight hydrocarbons Separation train Quench towerPENG-ROB, RK-SOAVEAromaticsBTX extractionWILSON, NRTL, UNIQUAC andariancestheirSubstituted hydrocarbons VCM plant Acrylonitrile planPENG-ROB, RK-SOAVEEther productionMTBE, ETBE, TAMEWILSON, NRTL, UNIQUAC and t

11、heir variancesEthylbenzene and styrene plantsPENG-ROB, RK-SOAVE ortheirWILSON, NRTL, UNIQUAC and variancesTerephthalic acidWILSON, NRTL, UNIQUAC and their variances(with dimerization in acetic acid section)五、Chemicals化工过程ApplicationRecommended Property MethodsAzeotropic separationsAlcohol separation

12、WILSON, NRTL, UNIQUAC and variancestheirCarboxylic acidsAcetic acid plantWILS-HOC, NRTL-HOC, UNIQ-HOCPhenol plantWILSON, NRTL, UNIQUAC and variancestheirLiquid phase reactions EsterificationWILSON, NRTL, UNIQUAC and variancestheirAmmonia plantPENG-ROB, RK-SOAVEFluorochemicalsWILS-HFInorganic Chemica

13、ls Caustic Acids Phosphoric acid Sulphuric acid Nitric acid Hydrochloric acidELECNRTLHydrofluoric acidENRTL-HF六、Coal Processing 煤力口工ApplicationRecommended Property MethodsSize reduction crushing, grindingSOLIDSSeparation and cleaning sieving, cyclones, precipitation, washingSOLIDSCombustionPR-BM, RK

14、S-BM (combustion databank)Acid gas absorption with Methanol (RECTISOL) NMP (PURISOL)PRWS, RKSWS, PRMHV2, RKSMHV2,PSRK, SR-POLARAcid gas absorption withELECNRTLWaterAmmoniaAminesAmines + methanol (AMISOL)CausticLimeHot carbonate七、Power Generation 发电过程ApplicationRecommended Property MethodsCombustion

15、Coal OilPR-BM, RKS-BM (combustion databank)Steam cycles Compressors TurbinesSTEAMNBS, STEAM-TA八、Synthetic Fuel合成燃料ApplicationRecommended Property MethodsSynthesis gasPR-BM, RKS-BMCoal gasificationPR-BM, RKS-BMCoal liquefactionPR-BM, RKS-BM, BWR-LS九、Environmental 环境ApplicationRecommended Property Met

16、hodsSolvent recoveryWILSON, NRTL, UNIQUAC and variancestheir(Substituted) hydrocarbon strippingWILSON, NRTL, UNIQUAC andvariancestheirAcid gas stripping from Methanol (RECTISOL) NMP (PURISOL)PRWS, RKSWS, PRMHV2, RKSMHV2,PSRK, SR-POLARAcid gas stripping from:WaterAmmoniaAminesAmines + methanol (AMISO

17、L)CausticLimeHot carbonateELECNRTLAcids Stripping NeutralizationELECNRTL十、Water and Steam水和蒸汽ApplicationRecommended Property MethodsSteam systems CoolantSTEAMNBS, STEAM.TA十、Mineral and Metallurgical Processes采矿和冶金ApplicationRecommended Property MethodsMechanical processing: CrushingGrindingSievingWashingSOLIDSHydrometallurgy