局部组成型的互扩散系数模型

根据局部组成概念建立了混合物中互扩散系数与自扩系数的关系,并以分子集团迁移的概念建立了混合物中组分的自扩散系数的预测方法,由此预测二元系的自扩散系数和互扩散系数与实验结果符合良好,比经典的Ｈａｒｔｌｅｙ模型有了很大地改进。     

含氢气体水合物生成条件的测定和计算

利用全透明蓝宝石水合物静力学实验装置测定了12组含氢气体混合物（包括5个二元系、4个三元系和3个四元系）在纯水中的水合物生成条件.将Chen-Guo水合物模型应用于含氢体系水合物生成条件的计算,计算中选用PR状态方程以及刘昆元和汪文川提出的混合规则计算含氢气体混合物的组分逸度系数,并对混合规则中的二元交互作用参数进行了重新回归.实验测定的12组含氢气体混合物水合物生成条件的计算结果和实验结果符合得很好.     

ZrO2—Y2O3ZrO2—MgO赝二元系相平衡的研究

用双亚点阵模型处理了ZrO_2-Y_2O_3、ZrO_2-MgO系统中的体心立方ZrO_2基固溶体相。用正态分布函数和样条函数相结合的方法,由部分相图数据优化了上述赝二元系中各相的相互作用参数,并用优化的相互作用参数及本工作估计的各氧化物的点阵稳定性参数计算了上述赝二元系相图。此外,还用DTA和X射线衍射方法测定了赝二元系在1300℃以下的固态相关系。计算结果与实验结果符合。     

水-丙酸二元体系汽液平衡的热力学性质

用新型泵式沸点仪测定了在101.325kPa下水-丙酸二元系在不同液相组成时的沸点,用过量自由焓函数Q,采用间接法由Tpx推算了水-丙酸二元系的汽相平衡组成y。汽相的非理想性用截至第二项的维里系数的状态方程求出汽相混合物中组分逸度系数。二元体系活度系数的关联分别用Wilson模型、NRTL模型、Margules模型和vanLaar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。用所得的液相活度系数来计算三个二元体系的过量吉布斯自由焓函数GE/RT。计算的泡点温度与实验测得的沸点温度吻合良好,由面积积分法检验这些模型参数计算的二元体系相平衡数据,得到很好的热力学一致性。     

水-乙酸二元体系汽液平衡的热力学性质分析

用新型泵式沸点仪测定了在101.325kPa下水-乙酸二元系在不同液相组成时的沸点,用过量自由能函数Q,采用间接法由Tpx推算了水-乙酸二元系的汽相平衡组成y。汽相的非理想性用截至第二项的维里系数的状态方程求出汽相混合物中组分逸度系数。二元体系活度系数的关联分别用Wilson模型、NRTL模型、Margules模型和vanLaar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。所得的液相活度系数来计算三个二元体系的过量吉布斯自由能函数GE/RT。计算的泡点温度与实验的所测得的沸点温度吻合良好,由面积积分法检验这些模型参数计算的二元体系相平衡数据得到很好的热力学一致性。     

液体混合物密度和粘度的实验测定

<正> 本文分别在四个温度下,对乙酸乙酯+正己烷、氯仿+正己烷、四氯化碳+丙酮、乙酸乙酯+丙酮、四氯化碳+甲苯、氯苯+甲苯这6个二元液体混合物的密度和粘度进行了实验测定。包括纯物质在内,总的实验点数为244点。混合物均是涉及极性组分的系统。 根据所测二元系具有易挥发的特点,采用特别加工的密度瓶和乌氏(Ubbelohde)粘度计。     

新的分子热力学模型及其应用(Ⅱ)——在金属溶剂萃取体系中的应用

将文(Ⅰ)提出的径向分布函数表达式与Flory-Huggins公式相结合,建立了新的非电解质溶液分子热力学模型.将其应用于复杂的金属溶剂萃取有机相体系,仅用3组二元体系实验数据,即可预测DEHPA萃取Cu、萃取Co及萃取Cu、Co各萃取有机相体系中各组分的活度系数和萃取反应热力学平衡常数,预测计算中,没有引入可调参数,而预测结果与实验结果相当吻合.     

二氧化碳与乙醇和异丙醇的二元汽液平衡

应用汽液双循环高压相平衡装置，测定了二氧化碳－乙醇和二氧化碳－异丙醇二元混合物分别在３０３．１５Ｋ，３１０．１５Ｋ和３２９．１５Ｋ，压力范围为１．７８～１０．０４ＭＰａ下的汽液相平衡数据。用ＤＤＬＣ－ＳＲＫ方程关联两个二元体系的汽液相平衡数据，计算值与实验值吻合良好。     

两种特性的涂料类有机混合物闪点模型预测

为了简化与扩展热力学推导的闪点预测模型,提出由UNIFAC活度系数模型与二元汽液平衡的实验得出二元互溶溶液的超额Gibbs自由能,评判区分溶液的理想与非理想性的方法。选择实用的2种涂料类有机混合物配方成分的二元与三元混合溶液,实验研究闪点变化规律,并与Raoult定律、活度系数模型(Wilson、NRTL、UNIQUAC)和UNIFAC模型的预测值比较。结果表明:理想性物系可直接由Raoult定律预测闪点(平均绝对误差AAD1.0℃);而非理想性物系适宜用3种活度系数模型(AAD2.5℃)或UNIFAC模型(AAD1.0℃)预测闪点。可为涂料类有机混合物的火灾爆炸危险性控制提供可靠闪点预测数据。     

1,2-丙二醇/乙醇混合物液相导热系数的实验研究

乙醇和1,2-丙二醇是重要的化工原料,以其作为主要组分的多元低温载冷剂在低温工程技术中具有重要的应用价值。为了给1,2-丙二醇/乙醇混合物的工程应用和科学研究提供基本的热物性数据,在233—313 K的温度范围内,利用瞬态热线法测量装置对乙醇、1,2-丙二醇及摩尔分数分别为0. 2,0. 4,0. 6和0. 8的1,2-丙二醇/乙醇二元液相混合物的导热系数进行了实验研究。采用二阶Scheffé多项式,将混合物的导热系数实验数据拟合为温度和质量分数的关联方程,实验数据与关联方程的最大偏差和平均绝对偏差分别为0. 48%和0. 12%。利用5种二元液体混合物的导热系数预测方法对1,2-丙二醇/乙醇混合物的导热系数进行了估算,根据预测结果与实验值的偏差,从工程应用及方程形式上推荐使用幂率法对液体混合物的导热系数进行预测。     

High pressure vapor-liquid equilibria of binary system 1,1,1-trifluoroethane (HFC-143a)+propane (HC-290)

Isothermal vapor-liquid equilibrium data were measured for the binary mixture of 1,1,1-trifluoroethane (HFC-143a)+propane (HC-290) at six equally spaced temperatures between 268.15 and 318.15 K by using a circulation-type equilibrium apparatus. The phase composition at equilibrium was measured by gas chromatography. The experimental data were compared with the calculated data based on the Carnahan-Starling-De Santis (CSD) equation of state. Good agreement between experimental and calculated data indicates that the CSD equation of state can be used to estimate thermodynamic properties for the mixture of HFC-143a+propane in the range of temperatures between 268.15 and 318.15 K. The binary system of HFC-143a+propane exhibits azeotropes.     

Phase equilibrium in acetone-water-mesityl oxide-diacetone alcohol four-component system

The liquid-vapor equilibrium is measured for acetone-mesityl oxide, acetone-diacetone alcohol, and mesityl oxide-diacetone alcohol binary systems and for three ternary systems. Activity coefficients for these systems are found. The binary interaction parameters of the NRTL equation for the components of a given reaction mixture are calculated from experimental data using the PRO/II SimSci software package. The vapor-liquid equilibrium is modeled and an analysis of the phase diagram is presented.     

Phase stability analysis using the PC-SAFT equation of state and the tunneling global optimization method

Phase stability calculation is a very important topic in phase equilibrium modeling. Usually the phase stability problem is solved by minimization of the tangent plane distance (TPD) function, the sign of the objective function at its global minimum indicating the state of the mixture at given conditions. The TPD function is non-convex and may be highly non-linear, many phase stability problems being really challenging. The tunneling global optimization method had been successfully used for solving a variety of phase equilibrium problems, including stability, with cubic equations of state (EoS). In this work, we test the ability of the tunneling method to solve the phase stability problem for more complex EoS like PC-SAFT. Calculations are performed for several benchmark problems, for mixtures of non-associating molecules, from binaries to multicomponent. In one example, the mixture contains hydrogen sulphide, for which the three parameters required by the PC-SAFT EoS were unavailable in the literature. These parameters, as well as the binary interaction parameter (BIP) between hydrogen sulphide and methane, were calculated based on experimental data.     

Calculation of mixture equilibrium binary interaction parameters using closed cup flash point measurements

Proper design and operation of separation processes are highly dependent on phase equilibrium calculations. The common method to treat polar/nonpolar systems, and also mixtures of normal compounds where the sizes are significantly different is to use binary interaction parameters. This paper presents a method to calculate mixture binary interaction parameters using closed cup flash point measurements. The measured and literature closed cup flash points of different binary mixtures (ethanol + n-octane, 1-propanol + n-octane, 1-propanol + n-decane, n-octane + n-decane, 1-propanol + water, 1-butanol + n-octane, 2-butanol + n-octane, and water + propionic acid) are used to calculate binary interaction parameters. These binary interaction parameters together with common activity models are then used to calculate vapor–liquid equilibrium compositions of different binary mixtures considered in this study. The validity of the proposed method was successfully approved by comparing the calculated equilibrium compositions with experimental data.     

Measurement of excess enthalpies using a high-pressure flow microcalorimeter and determination of binary interaction parameters for thermodynamic models

While an equation of state (EOS) plays a critical role in estimating thermodynamic properties, employing it in the determination of binary interaction parameters is extremely important. In general, these parameters can be determined from phase equilibrium data. However, data collection from experiments is a time-consuming and tedious process. In this study, after measuring the excess enthalpies of binary systems containing CO₂ by high-pressure flow isothermal microcalorimetry (IMC), we determined the EOS binary interaction parameters, specifically, the Peng-Robinson EOS binary interaction parameters. These binary interaction parameters obtained by IMC were compared with those obtained by vapor-liquid equilibrium (VLE) experiments. Hence, high-pressure flow IMC appears to be an effective method for the determination of interaction parameters that are used in the estimation of thermodynamic properties. Further, the Flory-Huggins interaction parameters of a binary mixture CO₂ containing with various mole compositions were also estimated by employing high-pressure IMC.     

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。     

正丁醇-氯苯-苯乙酮三元体系等压汽液平衡的测定与关联

正丁醇-氯苯常压下存在最低共沸现象,首先应用汽液平衡法从6种备选溶剂中筛选出苯乙酮作为最佳萃取剂,然后分别测定了正丁醇-氯苯、正丁醇-苯乙酮、氯苯-苯乙酮3个二元体系以及正丁醇-氯苯-苯乙酮三元体系在101.33 kPa下的汽液平衡数据。所有实验数据都通过了Herington法和Van Ness法的热力学一致性检验,采用Wilson、NRTL和UNIQUAC 3种活度系数模型进行关联计算,其二元拟合数据与实验数据吻合较好。使用关联得到的二元交互参数推算三元汽液平衡数据,并与实验值进行对比,偏差在合理范围以内。结果表明,苯乙酮作为萃取剂可以有效地改变正丁醇与氯苯的相对挥发度,在溶剂质量比为1：1时能够使共沸现象消失。为工业上使用萃取精馏分离正丁醇-氯苯体系提供参考,也为汽液平衡数据库补充新的内容。     

What does the NRTL model look like? Determination of boundaries for different fluid phase equilibrium regions

The adequate correlation of experimental phase equilibrium data by using any thermodynamic model represents a key point for the rigorous design of the chemical processes. However, this data correlation process remains a challenging problem, due to the high nonlinearity of the models used and the consequent problems of convergence. The present work analyzes the nonrandom two-liquids mode (NRTL) model to check the relation between the values of the binary interaction parameters and the corresponding phase equilibria that the NRTL model can or cannot reproduce. Additionally, in the case of the LLE, empirical equations have been established as a function of the nonrandomness parameter, to model the trajectory of the different miscibility boundaries observed. These functions can be used as constraints in the experimental data correlation procedure to reduce the search space and guarantee the consistency of the obtained binary interaction parameters with the experimental behavior of the system under study.     

热力学状态方程二元交互作用参数估算模型开发

基于气液平衡理论,建立了热力学状态方程二元交互作用参数估算模型。首先,结合气液平衡理论、状态方程以及相应的混合规则建立气液相平衡数学模型;然后以气相组成误差平方和与压力相对误差平方和之和作为目标函数,并使用计算机编程,利用单纯形法进行优化求解,实现了热力学状态方程二元交互作用参数估算模型的开发;最后,用该模型对5组二元气液平衡体系中的组分二元交互作用参数进行估算,并根据估算出的参数对各体系的气相组成进行预测,结果显示,预测值与实验值的平均相对偏差均小于1％,表明该模型计算结果准确,可应用于气液平衡计算中。