应用分子聚集理论计算有机物水溶液双元体系的液液平衡

本文应用由分子聚集理论改进的van der waals方程和van Laar混合规则对六个有机物水溶液体系的液液平衡进行了计算,取得了满意的结果。这表明,本方法是值得进一步开发和推广应用。     

液液平衡和会溶现象

提出了液体混合的通用Gibbs自由能模型,据此建立了液液平衡的双节线、旋节线和临界点方程.这些方程不仅适用于小分子液体混合物,而且亦适用于高分子溶液.计算结果表明,它们能满意地描述各种类型的液液平衡及其会溶现象.     

用Newton-Raphson法拟合水-乙醇气液平衡体系的Wilson方程参数

利用Newton-Raphson法拟合了气-液平衡计算中最困难的二元含水体系(水-乙醇体系)气液平衡组成的Wilson方程参数.结果表明,该方法简单,计算精度高,有理论和实际意义.在全部浓度范围内与实验值比较,结果说明,Wilson方程能很好地应用于该体系,计算结果令人满意.     

醋酸脱轻塔汽液平衡模拟计算

介绍了醋酸脱轻塔汽液平衡计算,通过醋酸体系的二元汽液平衡数据和三元液液平衡数据,回归出醋酸体系的主要二元交互作用参数,用NRTL有序双液方程与Hayden-O′Connell联立方程对非理想缔合体系的汽(液)液平衡的模拟计算,计算出醋酸精馏体系的汽液平衡与液液平衡、焓差和密度,理论模拟出醋酸脱轻塔各塔盘的流量、温度和压力与实际醋酸生产非常接近,其精度完全可满足醋酸生产的要求,对醋酸的生产具有重要的指导和借鉴意义。     

基于MPHC活度系数模型关联烃－水体系液－液平衡

基于普遍化范德华配分函数理论，应用由局部组成概念导出的方阱流体配位数模型导出了链状分子混合物的配位数模型，并由此建立了一个新的活度系数模型；将其应用于高度非理想体系汽－液平衡活度系数的关联，结果与Ｗｉｌｓｏｎ方程相当，但方程参数随温度变化较小；其于Ｎｅｗｔｏｎ－Ｒａｐｈｓｏｎ－Ｇａｕｓｓ液－液平衡算法，应用新模型对烃－水体系的液－液平衡进行了关联计算，结果优于ＮＲＴＬ方程     

基于MPHC活度系数模型关联烃－水体系液－液平衡

基于普遍化范德华配分函数理论，应用由局部组成概念导出的方阱流体配位数模型导出了链状分子混合物的配位数模型，并由此建立了一个新的活度系数模型；将其应用于高度非理想体系汽－液平衡活度系数的关联，结果与Ｗｉｌｓｏｎ方程相当，但方程参数随温度变化较小；其于Ｎｅｗｔｏｎ－Ｒａｐｈｓｏｎ－Ｇａｕｓｓ液－液平衡算法，应用新模型对烃－水体系的液－液平衡进行了关联计算，结果优于ＮＲＴＬ方程     

链状流体的分子热力学模型(IV)高分子系统的液液平衡计算

将作者先前提出的链状流体混合物的分子热力学模型应用于高分子系统液液平衡的计算,对具有最高会溶温度（UCST)和最低会溶温度（LCST）的高分子共混物的液液平衡,采用两个相互作用参数可以取得令人满意的关联结果。对具有LCST的高分子溶液的液液平衡计算,需对高分子链长作适当调整。     

尿素装置中高压系统汽液平衡的模拟计算

在综合分析现有ACWU体系热力学模型的基础上,采用扩展的UNIQUAC方程对该体系中、高压系统的汽液平衡进行模拟研究,开发了相应的计算程序.计算结果表明,该模型较好地反映了尿素工艺的中、高压段ACWU体系汽液平衡的规律,所开发的程序可用于尿素装置的合成塔和中压分离设备的汽液平衡模拟计算.     

变阱宽方阱链流体状态方程模拟制冷剂的汽液平衡

应用作者先前基于二阶微扰理论和PY2近似积分方程建立的可变阱宽方阱链流体状态方程模拟了纯制冷剂及其混合体系的汽液平衡。通过关联不同温度下制冷剂的饱和蒸气压和液体体积得到了18种纯制冷剂的分子参数,新方程计算的饱和蒸气压和液体体积总的平均偏差分别为1.11％和0.92％。结合简单混合规则,将此方程扩展到混合体系。研究发现,建立的方程可满意预测制冷剂二元混合体系除临界区附近外的汽液平衡,对两个三元体系汽液平衡的预测也取得了满意的效果,当引入一个与温度无关的可调参数时,关联精度大为提高,预示着新的方程可模拟制冷剂的汽液平衡。     

环己烷-正庚烷-N,N-二甲基甲酰胺体系液液相平衡测定与关联

采用平衡釜法测定了三元体系(环己烷+正庚烷+N,N-二甲基甲酰胺)在常压不同温度(30,40,50℃)下的液液相平衡数据。实验数据用Bachaman及Othmer-Tobias进行可靠性关联,关联结果表明数据的可靠性较好,根据实验结果绘制了三元相图。对不同温度下的液液平衡实验数据,分别用NRTL和UNIQUAC活度系数方程进行了关联,求得方程的二元交互作用系数,关联结果表明NRTL和UNIQUAC方程对该体系适用较好。由实验数据计算得到衡量N,N-二甲基甲酰胺抽提性能的参数(分配系数、分离因子、选择性系数)。     

用NRTL方程关联和预测离子液体-醇-水体系的液液相平衡

引 言 离子液体是指在室温或室温附近温度下呈液态的由离子构成的有机熔融盐,其特点是:几乎没有蒸气压,热稳定性好,大多数离子液体可以在高达300℃的温度范围内不分解,还对大量常见的有机物或无机物有良好的溶解性能,用离子液体替代传统的有机溶剂作为反应和分离的介质,也能有效地消除VOCs污染.因此,离子液体的研制和应用受到了广泛的关注[1-3].     

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.     

UNIFAC模型法计算含己内酰胺体系的相平衡(英文)

An extended liquid-liquid equilibrium (LLE) UNIFAC model is proposed to describe phase equilibria of mixtures containing caprolactam. In this model, caprolactam is introduced as a new group. New group interaction parameters are calibrated from 156 sets of liquid-liquid equilibrium data. The present model gives satisfactory correlation and prediction in liquid-liquid equilibrium, including quaternary systems containing the mixed solvent of an alcohol and an alkane. The model can be applied to predict caprolactam solubility in water and benzene accurately. Freezing point and vapor-liquid equilibrium of binary systems containing caprolactam are also predicted with the extended LLE UNIFAC model. Satisfactory prediction results are obtained.     

Prediction of the Phase Behavior of Hyperbranched Polymer Solutions by the Group Contribution Method

The purpose of this study is to predict the phase behavior of systems containing hyperbranched polymers by using a thermodynamic model based on the group contribution method, UNIFAC-FV, and considering an association term for the hydrogen bonding effect. After checking the validation of the model vapor-liquid equilibrium (VLE), bubble-point and liquid-liquid equilibrium (LLE), the cloud points for binary and ternary systems with different solvents were estimated from the proposed model. Furthermore, the activity of solvents in infinite dilution was predicted by this model. The results showed that the proposed model can estimate the phase behavior of solutions containing hyperbranched polymers with a good accuracy.     

环己酮-水-氟化钾及环己酮-水-碳酸钾的液液相平衡

采用气相色谱法测定了环己酮-水-氟化钾、环己酮-水-碳酸钾体系在25℃时的液液相平衡数据,相平衡数据表明产生的环己酮相中含有可以忽略的盐、水相中含有可以忽略的环己酮,因此采用氟化钾或碳酸钾可以有效地分离环己酮-水体系。分别采用Pitzer和NRTL方程计算水相和环己酮相中水的活度,将二者结合对液液相平衡进行了数学计算,计算值与实验值吻合较好,说明所选热力学模型对环己酮-水-氟化钾及环己酮-水-碳酸钾体系具有较好的计算精度,为采用氟化钾或碳酸钾分离环己酮-水体系提供了基础数据和设计依据。     

马丁-侯(M-H)状态方程计算二元液液平衡

本文将马丁-侯状态方程用于LLE数据关联.对二元体系,使用两个二元相互作用参数.在较大温度范围,参数处理成温度函数;温度差范围在30-40℃之内,参数可作为常数,取得良好的关联结果.基于二元LLE数据推算了二元低压VLE,结果与实验值符合较好.     

Application of UNIFAC models for prediction of vapor-liquid and liquid-liquid equilibria relevant to separation and purification processes of crude biodiesel fuel

Vapor-liquid equilibrium (VLE) of the methanol-biodiesel (BDF)/glycerin binary system and liquid-liquid equilibrium (LLE) of the water-BDF binary system and the methanol-BDF-glycerin and methanol-water-BDF ternary systems were predicted using several UNIFAC models: the latest original UNIFAC model, Kikic’s model, Fornari’s model, Dortmund-UNIFAC model, and LLE-UNIFAC model. The former VLE and latter LLE are used to design methanol recovery processes and separation and purification processes of crude BDF, respectively. Unfortunately, LLE data on the water-BDF binary system was not available. Instead, solubility of water in fatty acid methyl ester (one of the BDF constituents) was measured. By examining the deviation between predicted and experimental results, we determined which of the UNIFAC models was more useful for the design of those processes as follows: either the original UNIFAC model or Dortmund-UNIFAC model should be used for the methanol recovery process. The LLE-UNIFAC model and Dortmund-UNIFAC model were more useful for the recovery and water-washing processes of crude BDF and purification process of water-washed BDF, respectively.     

甲基戊烯酮-水-邻苯二酚三元物系液液相平衡数据的测定与关联

为了给甲基戊烯酮萃取脱酚过程的设计和开发提供数据支撑,采用液液平衡釜分别测出常压下30、40和50℃甲基戊烯酮-水-邻苯二酚体系的液液相平衡组成,并通过Hand方程、Bachman方程对结果进行可靠性检验,其相关性系数的平方均大于0.99。同时利用Aspen Plus软件选取NRTL模型对实验数据进行关联,得到该三元物系相应的热力学模型参数,并以此计算相应的相平衡组成,与实验数据对比两者间的相对均方根误差和绝对平均误差均为1%。因此,NRTL模型及其参数可准确描述该物系的相平衡行为。     

Liquid–liquid equilibrium correlations using lattice fluid equation of state with hydrogen bonding

The nonrandom lattice equation of state with hydrogen bonding (NLF-HB EOS) was examined for the correlation of liquid–liquid equilibria (LLE) for binary alcohol and hydrocarbon mixture in a wide pressure range. For hydrocarbon + alcohol mixtures the consideration of a hydrogen-bonding term in the lattice equation of state clearly improves the prediction for vapor–liquid equilibrium (VLE) as shown in previous works, but the prediction of LLE is still in question. In this paper, LLE data for alcohols (methanol and ethanol) + hydrocarbons (n-hexane to n-hexadecane) were correlated by NLF-HB EOS and results were compared with a cubic equation of state (Peng–Robinson EOS with the T–K Wilson based G^E model). Both equations of state showed similar degree of accuracies but with different number of adjustable parameters. The Peng–Robinson EOS based approach requires six temperature dependent coefficients for accurate calculation whereas NLF-HB EOS requires only two temperature dependent coefficients. The effects of varying hydrogen-bonding energies for NLF-HB EOS are discussed.     

水-异丁醛二元体系相平衡的测定和关联

水-异丁醛是部分互溶的体系,而且异丁醛化学性质较活泼,实验难度大,文献报导的一些数据精度较差,互相也不一致.本文对异丁醛易氧化、易聚合的化学特性进行了测定探索,并采取有效的措施,使实验数据有良好的重复性.本文测定了760mmHg下水-异丁醛二元体系液液平衡和汽液平衡数据,并用NRTL方程和多参数Wilson方程进行关联,根据汽液平衡实验数据、液液平衡实验数据以及同时联合两者分别回归得出三组二元参数,由二元参数所计算汽液平衡数据与实测数据相比较,均得到满意的结果.