不可逆热力学分离过程理论

将热力学原理和理论扩展到不可逆过程 ,形成不可逆热力学理论 ,并应用于扩散传质分离过程 ,建立不可逆热力学分离过程理论 ,其核心为描述多组分物系组分间相对运动的普遍化麦克斯韦尔 -斯蒂芬方程。该理论可合理地解释一些传质“奇异”现象 ,计算非理想物系传质扩散系数 ,预测多组分分离过程的传质速率和级效率 ,其模拟计算结果与实验测定值能很好地吻合。不考虑组分间的交互作用 ,视各组分效率相等的模型计算结果与实验测定值存在偏差 ,物系的非理想程度越大 ,偏差越大。     

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。     

水-乙酸-乙酸丁酯体系汽液平衡研究

用改进Rose釜测定了乙酸-乙酸丁酯、水-乙酸-乙酸丁酯(完全互溶区)体系在101.33 kPa下的汽液平衡数据。考虑乙酸的缔合效应,利用维里方程和Hayden-O'Connell(HOC)模型计算各组分的汽相逸度系数,校正汽相的非理想性,液相的非理想性全部归结到液相活度系数中予以校正。用NRTL,UNIQUAC模型对乙酸-乙酸丁酯的汽液平衡数据进行关联,并得到相应的模型参数、温度偏差和汽相组成偏差。比较二元体系的关联结果,用NRTL模型参数预测了三元汽液平衡数据,计算值与实验值吻合良好,预测精度较好,说明采用的模型参数是可靠的,能够为精馏的设计和模拟计算提供基础热力学数据。     

多组分精馏的模拟计算

本文提供了进行多组分精馏模拟计算的一种方法。该方法采用 UNIQUAC 模型,计算液相的活度系数,而汽相的逸度系数则采用截项的维里方程计算,因此该方法适用于非理想系统精馏的模拟计算。     

应用分子聚集理论计算含羧酸体系的汽液平衡

本文论述了应用“分子聚集理论”对含羧酸体系的汽相进行非理想性校正的计算方法.在低压下,含羧酸体系的汽相由于缔合从而引起组分的汽相逸度系数偏离1较大,故对汽相非理想性的校正是不容忽视的.汽相应用“分子聚集理论”改进的维里方程而液相采用UNIQUAC活度系数方程对含羧酸体系的汽液平衡进行计算,取得较好的结果.     

用Wilson方程计算汽相组分活度系数

Wilson方程通常用作计算液相组分活度系数。本文试图以Wilson方程计算汽相组分活度系数,初次实现用活度系数方程关联汽液平衡。文中选取在汽相存有缔合现象的羧酸水溶液进行关联计算,其结果显得比文献[1]的计算结果还要好。     

不规则形状A301氨合成催化剂内扩散有效因子

对于不规则形状A301氨合成催化剂,测定了其形状系数和球化的当量直径及高压下本征动力学方程,用SPSR法测定了不规则催化剂颗粒的曲折因子,根据多组分单一反应等温球形A301氨合成催化剂内反应-扩散-维模型,用正交配置法结合解非线性方程组的Broyden拟牛顿法求解了模型,获得了催化剂粒内各组分的浓度分布和催化剂的内扩散有效因子.利用所测得的高压下A301催化剂的总体速率对模型进行了检验,模型计算值和实验值吻合,表明球化模型和所得当量直径、曲折因子等模型参数可用于描述A30l催化剂内的反应-扩散过程及工程设计计算.     

醋酸—甲酸—醋酸甲酯三元体系汽液平衡的研究

本文测定了醋-甲酸-醋酸甲酯三元体系和醋酸-甲酸、醋酸-醋酸甲酯、甲酸-醋酸甲酯三组二元系在760mmHg下的汽液平衡数据。采用Tamir等提出的考虑汽相分子缔合反应及非理想性给予校正的热力学摸型计算汽相逸度系数,液相活度糸数用Wilson方程进行热力学关联。     

色谱法测烷烃和芳烃在正三十六烷中的热力学参数

通过气相色谱法,测定芳烃和部分正烷烃在正三十六烷中的亨利系数和无限稀释活度系数,同时测定正三十六烷的冰点.测定时考虑了固定液流失量和气相非理想性的校正,并用溶液热力学理论分析和讨论了无限稀释活度系数和温度的关系以及亨利系数和溶质碳数的关系.结果表明:无限稀释活度系数随着温度的升高而减少,亨利系数随着溶质碳数的增加而减少.     

Effect of activity coefficient models on predictions of secondary organic aerosol partitioning

Several available models for predicting organic aerosol activity coefficients are compared by examining their effect on predictions of secondary organic aerosol (SOA) concentrations and aerosol water uptake in laboratory and atmospheric systems. Activity coefficient models studied include Ideal behavior, the Wilson and NRTL equations, and UNIFAC in standard form, with revised interaction parameters, and with no temperature dependence. Wilson and NRTL binary interaction parameters were fit from UNIFAC predictions of activity coefficients. SOA model simulations were performed for different combinations of primary organic aerosol (POA) composition, SOA composition, and relative humidity. All of the activity coefficient methods predict similar results for mixtures of similar components, but for highly dissimilar aerosol mixtures, the Ideal, Wilson and NRTL models tend to predict higher SOA concentrations and aerosol water uptake compared to UNIFAC. Different versions of UNIFAC gave nearly identical results for most scenarios. Computational requirements are lowest for Ideal, followed by Wilson, and then NRTL and UNIFAC models.     

THE APPLICATION AND COMPARISON OF FOUR ACTIVITY COEFFICIENT MODELS IN VAPOR-LIQUID EQUILIBRIUM AND DISTILLATION CALCULATIONS

Four well-known activity coefficient models (Wilson,NRTL,McCann and UNIFAC),coupled withvirial equation and tridiagonal matrix method,have been applied to the vigorous computation of variousnon-ideal distillation processes.The NIDISTL program developed by authors has been tested for 33 distil-lation systems,with more than one hundred calculations performed.18 sets of binary vapor-liquid equilibrium data were chosen for the parallel comparison of these activ-ity coefficient models,each set was fitted to Wilson,NRTL,and McCann equations respectively by us-ing nonlinear least square technique.The binary parameters so determined were used to predict the bubblepoint equilibrium data of 18 binary and 8 derived multicomponent systems.The predictions of four mod-els were compared with experimental data.Five examples were presented to illustrate the consistency of distillation calculation results using dif-ferent coefficient models.     

Prediction and experimental determination of vapour-liquid equilibria for benzene + Cyclohexane + 1-Butanol mixtures at 101.325 kPa

This article reports experimentally determined vapour-liquid equilibrium data for benzene + cyclohexane + 1-butanol mixtures at constant pressure of 101.325 kPa, and compares the results with those predicted by the group contribution methods ASOG-KT and UNIFAC and by the Wilson, NRTL and UNIQUAC models after calculation of their adjustable parameters from the corresponding binary systems.     

Measurement,correlation and prediction of binary vapor-liquid equilibria for alcohol-tetrachloroethene systems

Experimental isobaric vapor-liquid equilibria of binary mixtures of tetrachloroethene with ethanol, 2-propanol, 2-butanol and 2-pentanol have been measured at 101.08 kPa. The UNIFAC (Fredenslund et al., 1975), a group contribution model and the activity coefficient models of Margules and Van Laar (as presented by Carlson and Colburn, 1942), Wilson (1964), NRTL (Renon and Prausnitz, 1968) and UNIQUAC (Abrams and Prausnitz, 1975) have been used to predict the vapor composition from measured T-x data of ten binary mixtures of alcohol-tetrachloroethene including these four systems. The average absolute deviation between the experimental and the predicted vapor composition with the UNIFAC model ranges from 0.006 to 0.023 mole fraction and that with the activity coefficient models ranges from 0.003 to 0.038. The maximum deviation in both the cases occurred in the data of 1-propanol (Venkateswara Rao et al., 1980).     

α-蒎烯+柠檬烯和对伞花烃+柠檬烯体系常压汽液平衡的测定与关联

利用改进的Ellis平衡釜测定了α-蒎烯+柠檬烯和对伞花烃+柠檬烯两个二元体系在100.7 kPa条件下的汽液平衡数据, 所测数据符合热力学一致性。以压力为目标函数使用最小二乘法拟合了Liebermann-Fried、Wilson、NRTL、UNIQUAC模型能量参数, 并将4个溶液模型的汽液平衡计算结果与UNIFAC模型的计算结果做比较。结果显示Liebermann-Fried模型对等压汽液平衡数据的拟合效果较精确。     

Measurement and correlation of VLE data for α-pinene + limonene and p-cymene + limonene systems under atmospheric pressure

利用改进的Ellis平衡釜测定了α-蒎烯+柠檬烯和对伞花烃+柠檬烯两个二元体系在100.7 kPa条件下的汽液平衡数据, 所测数据符合热力学一致性。以压力为目标函数使用最小二乘法拟合了Liebermann-Fried、Wilson、NRTL、UNIQUAC模型能量参数, 并将4个溶液模型的汽液平衡计算结果与UNIFAC模型的计算结果做比较。结果显示Liebermann-Fried模型对等压汽液平衡数据的拟合效果较精确。     

Comparison of different solubility equations for modeling in cooling crystallization

In this paper we evaluate the sensitivity of using different solubility models on cooling crystallization. Specifically, the cooling crystallization of acetaminophen in ethanol is investigated. Empirical, correlative thermodynamic (namely van Laar, Wilson, and NRTL) and predictive thermodynamic (namely MOSCED, NRTL-SAC, and UNIFAC) models are considered. Equilibrium solubility model prediction determines the predicted supersaturation profile. The different solubility equations are used within a population balance model for prediction of crystal size properties. Incorrect prediction of the supersaturation profile results in incorrect prediction of crystal size distribution. The NRTL model was found to be more accurate at predicting equilibrium solubility and consequently crystal size. After the solubility sensitivity is evaluated, two methods are proposed to make the crystallization model more robust against solubility model errors.     

COMPOSITION DERIVATIVES OF ACTIVITY COEFFICIENT MODELS (FOR THE ESTIMATION OF THERMODYNAMIC FACTORS IN DIFFUSION)

Derivatives of activity coefficient models are needed for the evaluation of the thermodynamic factors that arise in the equations that describe diffusion in multicomponent systems. A general framework for the evaluation of these thermodynamic factors is presented together with specific results for the Margules, Van Laar, Wilson, NRTL and UNIQUAC activity coefficient models.     

Vapor‐Liquid Equilibrium of MTBE‐Methanol,MTBE‐Methanol‐Calcium Chloride and MTBE‐Methanol‐Lithium Chloride Mixtures

Isobaric vapor‐liquid equilibria of methyl tert‐butyl ether (MTBE)‐methanol, MTBE‐methanol‐calcium chloride, and MTBE‐methanol‐lithium chloride mixtures were measured at 93.57 kPa using a Malanowski equilibrium still which circulates both the vapor and liquid phases. The experimental results of the salt‐free system showed that MTBE‐methanol forms a minimum boiling azeotrope of 69.80 mol.‐% MTBE at 93.57 kPa and 322.67 K. The experimental results of the salt‐free system were predicted using the original UNIFAC and the UNIFAC‐Dortmund methods, where the vapor‐phase compositions were predicted with root‐mean‐square deviations (RMSD) of 0.0046 and 0.0091, respectively, and the bubble point temperatures were predicted with RMSD of 0.36 and 0.71 K, respectively. The Wilson and the nonrandom two‐liquid (NRTL) models could satisfactorily correlate the experimental data of the salt‐free mixtures with RMSD in the vapor‐phase compositions calculation of 0.0047 and 0.0059, respectively and in bubble‐point temperatures calculation of 0.20 and 0.40 K, respectively. Addition of either calcium chloride or lithium chloride to the MTBE‐methanol mixtures resulted in salting‐out the MTBE and shifting the azeotropic point to a vapor composition of 76.5 mol.‐% and 93.0 mol.‐% MTBE, respectively. Both the Tan‐Wilson and Tan‐NRTL models could satisfactorily predict the bubble‐point temperatures of the MTBE‐methanol‐calcium chloride mixtures with RMSD of 0.143 and 0.130 K, respectively, and the vapor phase compositions with RMSD of 0.0055 and 0.0041, respectively.     

Isobaric vapor-liquid equilibrium of 2-propanone+2-butanol system at 101.325 kPa: Experimental and molecular dynamics simulation

Isobaric vapor-liquid equilibrium (VLE) data for binary mixtures of 2-propanone+2-butanol have been measured at 101.325 kPa. The measurements were in a modified recirculating type of Othmer equilibrium still. All the data passed the thermodynamics consistency test and no azeotropic behavior was exhibited. The experimental VLE data were correlated with the Wilson, non-random two-liquid (NRTL) and universal quasi-chemical (UNIQUAC) activity coefficient models. The correlation results showed that the experimental data were well correlated with those models. The experimental data also showed slight deviations from the predicted results using UNIFAC and modified UNIFAC (Dortmund) models. To gain more insight into the nature of interactions between 2-propanone molecule and alcohol, we analyzed the hydrogen-bonds, the electrostatic (Coulomb) interactions, and the van der Waals (Lennard- Jones) interaction energies extracted from MD simulations. In addition, the structural property of liquid phase was characterized through radial distribution function (RDF) to establish favorable interactions between 2-propanone and 2-butanol in the mixture.