含盐体系汽液平衡的测定方法和测定仪器的研究

针对含盐体系汽液平衡测定的特点及常用测定仪器和方法中的问题，改制了具有沸点仪和双循环平衡釜双重功能CS－Ⅱ型VLE测定仪，并以拟表态法测定了含盐体系汽液平衡的泡点线和平衡液相恒盐浓度下的露点线，新测定仪能避免用双循环仪器时极易出现的流动不稳定性和爆沸现象，成功地测定了氯化钙平衡液相浓度为5％的CaCl2-丙酮（1）－甲醇（2）体系的汽液平衡数据。     

若干酮—醇体系的汽液平衡

本文用流动汽液平衡釜测定了戊酮－３－正丙醇丁酮－戊醇－１－两个体系三个温度下的等温液平衡数据，三个温度下的数据均通过热力学一致性检验，并用Ｗｉｌｓｏｎ方程和ＵＮＩ－ＱＵＡＣ方程对数据进行了关联，平均汽相偏差小于０．０１，精度令人满意。     

若干酮－醇体系的汽液平衡

本文用流动汽液平衡釜测定了①戊酮－３－正丙醇③丁酮－戊醇－１两个体系三个温度下的等温汽液平衡数据，三个温度下的数据均通过热力学一致性检验，并用Ｗｉｌｓｏｎ方程和ＵＮＩ－ＱＵＡＣ方程对数据进行了关联，平均汽相偏差小于０．０１，精度令人满意。     

苯—正庚烷—乙醇三元体系加压汽液平衡的研究

用双循环武加压汽液平衡装置测定了苯-正庚烷-乙醇三元体系在101.3、302.5、506.8、709.3、810.6 kPa下的汽液平衡数据。根据有关二元体系在对应压力下的汽液平衡数据所求得的能量配偶参数,对该体系的汽液平衡进行了预测,计算值与实验值符合良好。     

甲酸—乙酸—水—氯化镁体系汽液平衡中的盐效应

采用Otsuiki-Williams式汽液平衡仪在9.866×10~4Pa下测定了甲酸-水、乙酸-水、甲酸-乙酸、甲酸-乙酸-水体系无盐和加氯化镁后各体系的汽液平衡数据,绘制了两组分和三组分体系相图。相图表明氯化镁有明显的盐效应。     

甲酸—乙酸—水—氯化钙体系汽液平衡盐效应（Ⅱ）

研究了加入恒定浓度分别为0.8和1.0 mol/(kg溶剂)的氯化钙的甲酸-乙酸-水体系的汽液平衡盐效应以及盐浓度对体系汽液平衡盐效应的影响。用汽液相等浓线及所划分的区域和等挥发度线分析判别了盐浓度对盐效应的影响以及由此引起的各区域挥发度的变化情况。结果表明,氯化钙对甲酸、乙酸的盐析效应随盐浓度增加而增强。     

基于PSRK模型预测高分子溶液汽液平衡

为了更好地预测高分子溶液的汽液平衡,本文应用PSRK模型改进的混合规则[即将组合项(∑xiInb／bi)与原UNIFAC模型中的组合项(Flory-Huggins项)相抵消所获得的简化的混合规则]来计算方程的能量参数α。为了计入自由体积效应对高分子溶液的过量Gibbs自由能的贡献,在计算体积参bij时,将原混合规则中的指数修订为bij^1/2(bi^1/2 bj^1/2)/2。应用PSRK模型结合改进的混合规则预测二元高分子溶液体系的汽液平衡,结果表明新模型的计算精度是令人满意的。     

Vapor-liquid and liquid-liquid equilibria of water, 2-methoxyethanol and cyclohexanone: Experiment and correlation

Vapor-liquid equilibria and liquid-liquid equilibria of a ternary mixture consisting of water, 2-methoxyethanol and cyclohexanone and in addition of all binary subsystems were studied experimentally at several temperatures. A ternary corrective term in the expression for the Gibbs free energy based on the NRTL model improves simultaneous representation of binary and ternary phase equilibria.     

Vapor-Liquid Equilibria for Chlorobenzene with Butan-1-ol, 2-Methylpropan-1-ol and 2-Methylpropan-2-ol at 94.6 kPa

Abstract

Vapor-liquid equilibria at 94.6 kPa, over the entire composition range were measured for three binary systems - butan-1-ol(1) + chlorobenzene(2), 2-methylpropan-1-ol(1) + chlorobenzene(2), 2-methylpropan-2-ol(1) + chlorobenzene(2)- using a Swietoslawski type ebulliometer. The composition (x ₁) vs. temperature (T) data were found to be well represented by Wilson model.     

Vapor-liquid equilibria for alcohol/hydrocarbon systems using the CPA Equation of state

The recently developed Cubic-Plus-Association Equation of State (CPA EoS) is extended in this study to binary systems containing one associating compound (alcohol) and an inert one (hydrocarbon). CPA combines the Soave-Redlich-Kwong (SRK) equation of state for the physical part with an association term based on perturbation theory. The classical van der Waals one-fluid mixing rules are used for the attractive and co-volume parameters, and b, while the extension of the association term to mixtures is rigorous and does not require any mixing rules. Excellent correlation of Vapor-Liquid Equilibria (VLE) is obtained using a small value for the interaction parameter (k_ij) in the attractive term of the physical part of the equation of state even when it is temperature-independent. CPA yileds much better results than SRK and its performance is similar to that of other association models, like the Anderko EoS, and the more complex SAFT and Simplified SAFT EoS.     

顺丁烯二酸酐-癸二酸二丁酯二元体系等温气液平衡

利用改进的沸点仪测定了顺酐-癸二酸二丁酯二元体系在413.15, 433.15和453.15 K下的等温气液平衡数据以及纯癸二酸二丁酯和顺酐的饱和蒸气压数据. 通过与文献值对比, 验证了此方法的可靠性. 同时, 将实验数据回归得到了纯癸二酸二丁酯和顺酐的Antoine常数. 利用NRTL方程进行了气液平衡数据的关联推算, 得到了顺酐-癸二酸二丁酯二元体系的NRTL模型参数. 利用UNIFAC基团贡献法对实验数据进行了预测, 其结果与实验值及运用NRTL方程拟合的结果吻合较好.     

Vapor-Liquid Equilibria in the Binary System Formed by Methyltertiarybutylether with Benzene at 490 and 709 mm Hg

Abstract

Isobaric vapor-liquid equilibria over the entire composition range are obtained from the measurement of the liquid phase composition versus boiling temperatures by means of a Swietoslawski type ebulliometer at 490 and 709 mm Hg for the methyl-tertiary-butylether(1) + benzene(2) system. The experimental composition (x) versus temperature (t) values could be represented well by both the Wilson and NRTL models. The optimum Wilson parameters have been used to calculate the excess Gibbs free energy.     

Bubble point temperatures of the binary mixtures of cyclohexanone with C1–C4 aliphatic alcohols at 94.8 kPa

Bubble point temperatures at 94.8?kPa, over the entire composition range, are measured for the binary mixtures of cyclohexanone with: methanol, ethanol, n-propanol, iso-propanol, and n-, iso-, sec-, and tert-butanols –?using a Swietoslawski-type ebulliometer. The liquid phase composition versus bubble point temperature measurements are well represented by the Wilson model.     

Combined chemical and phase equilibrium for the hydration of ethylene to ethanol calculated by means of the Peng-Robinson-Stryjek-Vera equation of state and the Wong-Sandler mixing rules

Due to the economics of the ethylene market and the subsidized production of fermentation-based ethanol in some countries, use of the ethylene hydration process to make ethanol has been steadily declining. The economics of this process might improve by combining the reaction and separation in a reactive distillation column, whose conceptual design requires a study of the combined chemical and phase equilibrium (CPE) of the reacting system. In this work, the Peng-Robinson-Stryjek-Vera equation of state was combined with the UNIQUAC activity coefficient model through the Wong-Sandler (WS) mixing rules in order to correlate the available experimental data for the vapor-liquid equilibria (VLE) of the ethylene-water, ethylene-ethanol, and ethanol-water binary systems at 200 °C. The interaction energies of the UNIQUAC model and the binary interaction coefficient of the WS mixing rules were used as the fitting parameters. From the optimum values of these parameters, both the VLE and the combined CPE of the ethylene-water-ethanol ternary system were predicted at 200 °C and various pressures. At this temperature, the catalytic activity of a H-pentasil zeolite has already been reported to exhibit a maximum for ethylene hydration, and also the experimentally measured two-phase region of the ternary system is sufficiently wide. By means of the reactive flash method, the chemical equilibrium compositions of the liquid and vapor phases were determined for several pressures, and the equilibrium conversion and the vapor fraction were calculated as functions of the ethylene to water feed mole ratio. It turns out that the vapor-liquid mixed-phase hydration of ethylene achieves equilibrium conversions much higher than those computed for a vapor-phase reaction that would hypothetically occur at the same conditions of pressure and feed mole ratio. It was found that the reactive phase diagram of the ternary system exhibits a critical point at 200 °C and 155 atm.     

Multiphase equilibria for mixtures containing water, isopropanol, propionic acid, and isopropyl propionate

Vapor pressures of isopropyl propionate and isobaric vapor-liquid equilibrium (VLE) properties of isopropyl propionate + isopropanol and propionic acid + isopropyl propionate were measured. Isothermal vapor-liquid-liquid equilibrium (VLLE) data were also determined experimentally for water + isopropyl propionate and water + isopropyl propionate + isopropanol at temperatures from 323.24 K to 373.15 K. The binary VLE and VLLE data can be correlated well with the NRTL-HOC and the UNIQUAC-HOC models. The ternary VLLE data were used to test the validity of two versions of the UNIFAC model and the NRTL-HOC and the UNIQUAC-HOC models with the parameters determined from the phase equilibrium data of the constituent binaries. The ternary VLLE data were also correlated with the NRTL-HOC and the UNIQUAC-HOC models and the Soave-Redlich-Kwong equation of state with the Wong-Sandler mixing rule.     

The use of the NRTLmKW model for predicting VLE data of binary systems from the excess enthalpy data

A new local composition model NRTLmKW has been used for correlation of 15 binary excess enthalpy data. The data, binary systems formed by hydrocarbons and alkanols, have been selected to give a wide representation of various kinds molecular interactions in solution. Further the model, basing on the results of the correlation, has been used for prediction of excess enthalpy and VLE (vapour-liquid equilibria) in these systems. The obtained results have been discussed from the point of view of intermolecular interactions and some recommendations have been made on the use of the NRTLmKW model for such calculation.     

Vapor-liquid equilibrium properties for confined binary mixtures involving CO2, CH4, and N2 from Gibbs ensemble Monte Carlo simulations

The effects of solid-fluid interactions on the vapor-liquid phase diagram,coexistence density,relative volatility and vaporization enthalpy have been investigated for confined binary systems of CO 2-CH 4,CO 2-N 2 and CH 4-N 2.The Gibbs ensemble Monte Carlo(GEMC) simulation results indicate that the confinement and the solid-fluid interaction have significant influences on the vapor-liquid equilibrium properties.The confinement and the strength of the solid-fluid interaction make the p-x i phase diagram move to higher pressure regions.They also make the two-phase region become narrower for each binary mixture.The strength of the solid-fluid interactions can cause increases in the coexistence liquid and vapor densities,and cause the decrease of the relative volatility and the vaporization enthalpy for the systems studied.As the pore width is decreased,the two-phase region of the binary mixture becomes narrower.