含碘化物系统汽液平衡的研究(Ⅰ)——碘化氢-水二元系

本文介绍了强电解质溶液碘化氢-水二元系的实验结果,以及对数据进行热力学处理和关联的情况。此外还用二元系的NRTL参数对醋酸-碘化氢-水三元系统的汽液平衡进行推算,并与部分实验数据作比较,在本文处理的浓度范围内,用NRTL关联式进行推算的效果良好。     

烃-醇系混合热的测量和汽液平衡数据的推算

用PICKER动态型微量热计测量了三个温度下八个烃-醇二元系的混合热数据.提出了一个研究烃-醇系热力学性质的新的热力学模型——拟化学溶液模型(QCSM),用该模型关联了混合热实验数据和部分体系的等温汽液平衡数据,计算值和实验值间符合良好.以混合热拟合得到的QCSM参数及其与温度的关系式,推算了8个烃-醇二元系的244个等温或等压汽液平衡数据,获得了满意的结果.汽相摩尔分数的平均误差为0.004—0.032.     

减压下正丁醇对甲基环己烷-甲苯系汽液平衡的影响

本文使用Rose-Williams平衡装置,测定了甲基环己烷—甲苯,甲基环己烷—正丁醇,甲苯—正丁醇三组二元体系在300和500mmHg下的汽液平衡数据,用Herington经验方法对所测数据进行了恒压下的热力学一致性检验。采用Wilson方程对三组二元系的汽液平衡数据进行了热力学关联,并用Wilson方程和UNIFAC方程推算了甲基环己烷—甲苯—正丁醇三元系在300和500mmHg下的汽液平衡数据。讨论了正丁醇对甲基环己烷—甲苯系汽液平衡的影响     

二甲基硫醚-二硫化碳-甲醇体系等压汽液平衡

用泵式沸点仪测定了100 kPa下二甲基硫醚-二硫化碳、二甲基硫醚-甲醇2个二元系以及二甲基硫醚-二硫化碳-甲醇三元系在不同液相组成时的汽液平衡数据,用Wilson、NRTL、Margules和van Laar模型分别对2个二元系活度系数进行关联,用最小二乘法求出其液相活度系数模型参数,用这些模型参数来计算其汽相组成y,根据过量Gibbs自由能函数Q(GE/RT),采用间接法由Tpx推算了2个二元系的汽相平衡组成。用所得的液相活度系数计算2个二元系的过量吉布斯自由能函数GE/RT,并由2个二元系与三元系回归出二硫化碳-甲醇二元系的NRTL模型参数。用3个二元系NRTL模型参数对所测的三元系数据进行关联,建立三元系汽液平衡的热力学模型并计算平衡时的汽相组成y和泡点温度。分别由Herington法和McDermott-Ellis法对2个二元系和三元系进行热力学一致性检验,结果表明这些相平衡数据满足热力学一致性。     

碳酸二甲酯-碳酸二乙酯-甲醇三元体系相平衡数据的推算

采用双循环汽液平衡釜测定了常压下碳酸二甲酯-碳酸二乙酯、碳酸二甲酯-甲醇、碳酸二乙酯-甲醇三组二元体系的汽液平衡数据,实验数据经Herington面积积分法检验符合热力学一致性。用Wilson模型分别对实验数据进行了关联,利用关联出的模型参数计算相应的汽相组成,并与实验值比较,二者符合良好。利用二元体系的汽液平衡数据,由Wilson方程推算了碳酸二甲酯-碳酸二乙酯-甲醇三元体系的汽液平衡数据。为建立碳酸二乙酯和碳酸二甲酯、甲醇的精馏分离数学模型提供了基础数据。     

从混合热推算含芳香族化合物体系的汽液平衡

运用Liebermann从G~E推算H~E的模型,反过来从H~E推算汽液平衡数据。提出了一个第三参数β,从实测的25℃H~E数据推算了十个体系的等温和等压汽液平衡数据。把模型从二元系推广到了三元系,利用从H~E数据拟合得到的二元参数,计算了两个三元系的汽液平衡数据,所得计算值与文献值比较,符合良好。比较了修正的Liebermann模型和NRTL模型,在从H~E数据推算汽液平衡时,前者不仅精度明显提高,而且只需要一个温度下的H~E数据。研究结果表明,用修正的Liebermann模型从H~E数据推算汽液平衡数据,对非理想不太强的或者弱缔合的体系都是十分适用的。     

甲醇-醋酸乙烯二元体系常压汽液平衡的研究

用改进Rose釜测定了甲醇-醋酸乙烯二元体系的常压（101.33 kPa）汽液平衡数据,结果表明甲醇-醋酸乙烯形成二元最低共沸物。试验数据通过了面积法热力学一致性检验,利用Wilson、NRTL、UNQUIC方程对试验数据进行关联和估算,得到了关联活度系数的参数值。汽相摩尔分数与试验值的最大相对偏差均〈-0.011 9,用Wilson方程参数推算了共沸点温度为58.65℃,液相甲醇摩尔分数为0.610 2,与试验数据相一致。     

含碘化物系统汽液平衡的研究(Ⅱ)——碘甲烷-碘化氢二元系

本文报道了碘甲烷-碘化氢二元系统稀溶液的汽液平衡。设计了一个在T、P、y的基础上进行热力学推算的计算程序,将推算结果与实验值进行比较,证明具有良好的热力学一致性,为多组份物系汽液平衡的推算提供了基础数据。     

环己烯、1,2-环氧环己烷和2-环己烯-1-酮二元和三元系的等压汽液平衡

作者采用改进的EC-2型汽液平衡釜测定了常压下(101.33kPa)环己烯、1,2-环氧环己烷、2-环己烯-1-酮3组二元系和1组三元系的等压汽液平衡(VLE)数据。对二元的等压汽液平衡实验数据作了热力学一致性检验和Wilson方程关联,求出了相应的Wilson方程配偶参数,用求得的参数推算了相应二元及三元系的VLE数据,并将其与实验值进行了比较,结果令人满意,可以满足工程上环己烯与其氧化产物分离设计的需要。     

丙酮-水-丙酮连氮体系汽液平衡测定与关联

采用汽液双循环平衡釜,在常压（101.3 kPa）下测定了丙酮-丙酮连氮二元组分物系以及部分丙酮-水-丙酮连氮三元组分物系的汽液平衡数据。实验数据经Herington面积积分法检验符合热力学一致性。通过化工过程模拟软件,分别采用Wilson、NRTL、UNIQUAC 活度系数模型对丙酮-丙酮连氮二元组分物系实验数据进行关联得到模型参数。并对汽液平衡的计算值与实验值进行比较,3种模型都吻合良好,其中由NRTL方程关联得到的计算结果最为适合,平均温度偏差和汽相组成偏差分别为0.0639 K和0.0048。从三元汽液相平衡数据中拟合出了丙酮-丙酮连氮、丙酮-水、水-丙酮连氮之间的NRTL方程相互作用参数。为验证数据及其二元相互作用参数的可靠性,利用关联出的丙酮-丙酮连氮模型参数计算出汽相组成与丙酮-丙酮连氮的二元数据比较,二者符合较好。实验和关联的结果为精馏分离丙酮-水-丙酮连氮汽液平衡体系提供了一定的基础数据。     

Understanding phase behaviors of multicomponent polymer mixtures based on a molecular thermodynamic framework combined with molecular simulation

A new molecular thermodynamic model based on a closed-packed lattice model is developed for multicomponent systems. Based on Monte-Carlo (MC) simulation results, we introduce new universal functions to consider the chain length dependence of polymers, and are able to obtain more accurate critical volume fraction results in liquid–liquid equilibrium (LLE) calculations. In associated blend systems, specific interactions are used to characterize strongly interacting polymer mixtures with a secondary lattice. To minimize the number of adjustable model parameters, chain length parameters are calculated in a conventional way using molecular weight and specific volume. Our proposed model successfully describes binary LLE for polymer-solvent systems. Furthermore, the model parameters obtained from these binary systems are directly used to predict corresponding LLE ternary systems, and the results were in good agreement with experimental data.     

甲醇-乙酸-丙酸多元体系汽液平衡

用新型泵式沸点仪测定了在100kPa下甲醇-乙酸、甲醇-丙酸、乙酸-丙酸3个二元体系以及甲醇-乙酸-丙酸三元系在不同液相组成时的沸点,并用间接法T-p-x(温度、压力和液相摩尔分数)推算了3个二元体系的汽相平衡组成。3个二元体系活度系数分别用Wilson模型、NRTL模型、Margules模型和van Laar模型进行关联,用最小二乘法求出了它们的液相活度系数模型参数,同时,用这些模型参数来计算它们的汽相摩尔分数。所得的液相活度系数来计算3个二元体系的过量吉布斯自由能函数,且所研究的所有体系中各组分之间不存在共沸点。用3个二元体系Wilson模型参数对所测的三元体系数据进行关联,建立该系统汽液平衡的热力学模型并计算平衡时的汽相摩尔分数和泡点温度。由面积积分法检验这些模型参数计算的3个二元体系相平衡数据,得到很好的热力学一致性。     

Calculation of solution-vapor thermodynamic equilibria by the method of minimizing the Gibbs energy

An algorithm of direct numerical minimization of the Gibbs energy for calculating the liquid-vapor thermodynamic equilibrium in multicomponent systems is proposed. The method makes it possible to simultaneously determine the distributions of concentrations in the vapor and solution and the vapor mole fractionwhen the temperature, pressure, and initial mixture composition are given. The developed algorithm is distinguished from the existing equilibrium calculation methods by a higher stability and the capability of obtaining solutions in the range of parameters in which the conventional algorithms are not able to produce a physically meaningful result. The Peng-Robinson equation of state is used to simulate the Gibbs energy. The accuracy of the proposed algorithm is illustrated by comparison with experimental data.     

2,2-二甲基丁烷+乙醇、+正丙醇二元体系常压汽液平衡的测定

使用自行设计的汽液平衡釜测定了常压下2,2-二甲基丁烷+乙醇和2,2-二甲基丁烷+正丙醇二元体系的汽液平衡数据,所得到的汽液平衡数据通过了Herrington面积法热力学一致性检验。实验数据用NRTL方程进行关联,采用关联得到的模型参数计算相应的汽相组成,并与实验值比较。汽相组成的平均偏差小于0.02,这说明NRTL模型适用于所研究的二元体系。     

Vapor–liquid equilibria for ethyl acetate + methanol and ethyl acetate + ethanol mixtures: Experimental verification and prediction

This work aims of the determination of a series of vapor–liquid equilibrium (VLE) experimental data at low pressure (70 kPa) for binary mixtures of ethyl acetate with methanol and ethanol. The Fischer's ebulliometer was used for the measurements of VLE data. A complete series of equilibrium data was obtained such as pressure, temperature and compositions of the liquid and vapor phases (PTxy). The two VLE data sets were submitted to a thermodynamic consistence test, where the deviations were evaluated in all variables, using the UNIQUAC activity coefficient equation. The magnitude of the average deviations was within the experimental uncertainty satisfying the Gibbs–Duhen equation. The data sets were also used to test the prediction of the UNIFAC model in its original and modified editions and the results were also within experimental uncertainties. Then a series of binary systems containing alcohols (methanol and ethanol) and esters (methyl and ethyl acetate) were collected from the literature for testing systematically the capability of the UNIFAC contribution method for this type of mixtures.     

On the predictive capabilities of CPA for applications in the chemical industry: Multicomponent mixtures containing methyl-methacrylate,dimethyl-ether or acetic acid

The predictive performance of the CPA (Cubic-Plus-Association) equation of state for applications relevant to the chemical industry is illustrated in this work. Three such applications inspired by industrial requests/interest are illustrated here, all of which involve aqueous multicomponent mixtures exhibiting vapor–liquid (VLE) and/or liquid–liquid (LLE) equilibrium. The first two cases include mixtures of methyl-methacrylate with acetone or methanol and dimethyl-ether with ethanol, respectively. In these two cases, the classical form of CPA is used. The third case involves aqueous mixtures with acetic acid, esters, ethers and alcohols, and in this case for water–acetic acid the CPA-Huron Vidal (CPA-HV) version of the model is used. For the latter binary mixture, new CPA-HV binary parameter sets are estimated using, among others, data for activity coefficients at infinite dilutions. The modeling approach is similar in all three cases, i.e. the binary parameters are solely fitted to binary data and thus all multicomponent calculations are considered predictions.It is shown that CPA correlations for binary systems are excellent in all cases using temperature independent parameters except for the acetic acid–water system for which different parameter sets at different temperatures can be recommended. Even with the use of CPA-HV mixing rules, modeling of the acetic acid–water system with few interaction parameters remains a challenging task. Excellent simultaneous VLE and LLE correlation is obtained for complex systems such as aqueous mixtures with ethers and esters. The multicomponent results are, with a few exceptions, very satisfactory, especially for the vapor–liquid equilibrium cases. For the demanding aqueous acetic acid–water containing systems, one parameter set is recommended at the end for modeling ternary or multicomponent mixtures containing acetic acid and water.     

醋酸-水二元系25——75℃恒温汽液平衡的研究

建立了利用静态法测定溶液蒸气压的装置,它包括平衡器、零压计、水银压差计、脱气室以及高真空设备。在此装置中测定了醋酸-水二元系在25—75℃范围内的蒸气压。为了得到完整的恒温汽液数据,利用我们先前发展的一个直接热力学方法来计算平衡汽相组成,计算时考虑了汽相缔合。本文中用表格形式发表了所得的计算结果。 为了拟合实验数据,用了一个由热力学推导得到的关联活度系数与温度的多项式,多项式参数由最小二乘法求得。利用这些参数,并外推至常压,预测所得泡点和汽相组成与文献报导的恒压实验数据,具有良好地一致。这些参数,可在低压至常压的广阔范围内的实际汽液平衡计算中使用。     

甲基二氯硅烷+甲基三氯硅烷+二甲基二氯硅烷+苯多元系常压汽液平衡研究

卤代硅烷的相平衡数据为硅烷生产所需,而这方面的研究又较缺乏,尤其是甲基乙烯基二氯硅烷生产中所需的汽液相平衡数据尚未见报道.今用新型泵式沸点仪测定了常压(101.325 kPa)下甲基二氯硅烷 甲基三氯硅烷 二甲基二氯硅烷 苯四元系及其四个三元体系和六个二元体系在不同液相组成时的泡点.由所测的二元系数据,用过量自由焓Q函数间接法推算了与之平衡的汽相组成.再用最小二乘法求出二元体系的最佳配偶液相活度系数模型参数.所得的六组最佳二元系Wilson模型参数符合热力学一致性,并用于该体系三元和四元系汽液相平衡数据的预测,将计算的泡点与实验测得的泡点作了比较,其拟合精度良好,关联结果令人满意,硅烷二元系、多元系的热力学模型及VLE数据可为该体系的分离设计提供必要的理论依据.     

Calculation of Vapor‐Liquid Equilibrium Data of Binary Mixtures Using Vapor Pressure Data

The design of plants or unit operations requires the knowledge of data for multicomponent systems. An approach is presented for the regression of binary interaction parameters required for the calculation of activity coefficients. Binary vapor pressure data are used to correlate these parameters for calculation of vapour/liquid equilibrium data. The advantage of the approach is the fact that only easily measured vapor pressure data are required. The procedure is demonstrated by means of two binary mixtures. Parameter regression, prediction of vapour/liquid equilibrium data as well as their experimental verification are demonstrated.     

Phase equilibria of mixtures containing CO2 and organic acids using the UMR-PRU model

The UMR-PRU model, which has been successfully tested in the past to the predictions of different type of phase equilibrium and thermodynamic properties in binary and multicomponent systems, is applied in this work to phase equilibria in mixtures containing CO₂ and organic acids. New interaction parameters are determined by fitting only binary vapor–liquid equilibrium data and then they are used to predict the vapor–liquid, solid–gas and solid–liquid–gas equilibria in CO₂/organic acid systems. Furthermore, the UMR-PRU model with the newly derived interaction parameters is applied to the prediction of the phase equilibrium in ternary mixtures consisting of CO₂, organic acids and water. Satisfactory results are obtained in all cases.