气液平衡的测定及理论研究进展

评述有机物系气液相平衡的测定方法、关联方法和推算方法。重点介绍液上气相色谱法与基团贡献法。     

USING THE GROUP-INTERACTION CONTRIBUTION APPROACH (GIC) IN MIXTURES 1. Prediction of Azeotropic Parameters

We have demonstrated the capability of the recently reported Group-Interaction Contribution Approach (GIC) (Pardillo-Fontdevila, 1997a) for predicting mixture properties. Up to day GIC approach has been reported exclusively for estimating pure-component properties. As a result: (1) it is reported a new approach for estimating mixture properties without the use of the Analytical-Solution-of-Groups Theory and (2) new models have been met for estimating azeotropic parameters in binary mixtures.

New models reported, based on GIC, distinguish between isomers in mixtures. These models give better estimates of the azeotropic parameters if estimates are compared with those obtained by the same equation but using the well-known Group Contribution method.

Estimation models reported in this work do not require of correlation equations for pure-component vapour pressures, as well as any equation for activity or fugacity coefficients. No algorithm is necessary for fitting equilibrium and azeotropic points     

新的N-甲酰吗啉UNIFAC基团相互作用参数

引　言目前国内外应用Ｎ 甲酰吗啉 (ＮＦＭ )溶剂回收苯产品的工业化装置已有数十套[1] .由于烃类与溶剂间的沸点差大 ,故含ＮＦＭ的ＶＬＥ数据罕见报道 .用ＵＮＩＦＡＣ法预测含ＮＦＭ体系ＶＬＥ数据的文献报道有 3种 :一是采用Ｔｉｅｇｓ等[2 ] 的基团参数表将ＮＦＭ划分为 1     

Isobaric vapor liquid equilibrium in binary mixtures of α-pinene,limonene and 1, 8-cineole

Isobaric vapor liquid equilibrium at atmospheric pressure has been determined for binary mixtures of (–) α-pinene, (+)-limonene and 1, 8-cineole. The Margules and Var Laar equations as well as the models proposed by Wilson, by Renon and Prausnitz (NRTL) and by Abrams and Prausnitz (UNIQUAC) were used to correlate the experimental data. The corresponding parameters for two binaries are reported here.     

基于UNIFAC模型的基团-OCOO-与-CH3,ACH,CH3OH和CH3COO-的交互作用参数估算与验证

Isobaric vapor-liquid equilibria (VLE) are experimentally measured for the binary systems of dimethyl carbonate (DMC) ethylene carbonate and methanol ethylene carbonate at 101.325kPa. The thermodynamic consistency of these experimental data is tested with an available statistic method. Interaction parameters of the carbonate group —OCOO— with the group —CH3, ACH, CH3OH and CHACO0— in UNIFAC model are determined using the experimental and literature VLE data. The results show that the calculated VLE data using the new UNIFAG parameters agree excellently with the experimental data in this work and in literature. These results are useful in the research on DMG and diphenyl carbonate synthesis by transesterification in design of reactor and distillation tower.     

一个新的基团贡献型状态方程——GC-MCSPT方程

将超额Gibbs函数模型与修正的硬球三参数状态方程(MCSPT方程)相结合,导出由基团贡献模型定义的状态方程参数混合规则.直接利用低温下的基团贡献模型参数,如UNIFAC模型、修正的UNIFAC模型(简称MUNIFAC)的交互作用参数,分别预测了二元强极性物系的低压和高压相平衡以及三元强极性物系的汽液相平衡.结果表明,新模型具有广泛的预测能力和满意的预测精度.     

正常沸点下液体蒸发焓的基团贡献计算法

用分子热力学方法建立了纯物质汽液平衡的推广vanderWaals模型 ,并据此得到了一个计算正常沸点下液体蒸发焓的方程 .它只含有一个与分子大小有关的参数 .这个参数的值与正常沸点下液体的摩尔体积成正比 ,且具有基团加和性 .为此 ,用 484个有机物回归得到了 45个基团增量 .对这些有机物的蒸发焓计算结果表明 ,与实验值的平均绝对偏差 (AAD)为 1.39% ,优于文献发表的其他方法     

水-二甲基甲酰胺-甲酸体系汽液相平衡的研究

用改进的Rose釜测定了水-N,N-二甲基甲酰胺（DMF）在101.33kPa、13.33kPa下的二元及水──DMF──甲酸在101.33kPa下的三元等压汽液相平衡数据．并对水──DMF汽液相平衡数据进行了关联,得出了相应的UNIQUAC,NRTL和Wilson模型参数．用Wilson模型推算了所测的三元汽液相平衡实验数据．结果令人满意．     

用Ha′la限制式结合γ~∞数据推算多元汽液平衡

提出了一种把Wilson方程参数间关系——Ha′la限制式和无限稀释活度系数相关联,用以估算三元系汽液平衡的方法。用汽液色谱测定挥发性溶质在不挥发性溶剂及混合溶剂中无限稀释活度系数,与Ha′la限制式相结合预测三元系汽液平衡,同文献位相比较:从Dortmund数据库的汽液平衡数据中选取了13组同时具有三元系和二元系汽液平衡数据的体系,用拟合和无限稀释活度系数及Ha′la限制式结合的方法求取Wilson参数,进而预测汽液平衡,与文献值相比较;又在三元系的三个二元系之间用同样办法进行相互推算;又利用两个二元系和三元系的一点数据进行预测;所得结果均较满意。为证明所用方法的可靠性,并对预测误差的置信度上限作了相应的估算。     

亚硝酸乙酯-乙醇-水三元体系汽液平衡的测定与关联

报道了一种测定汽液平衡的实验装置,在15.0℃～30.0℃的温度范围内测定了低压下亚硝酸乙酯──乙醇──水三元体系汽液平衡数据．并用NRTL方程进行了关联,计算值与实验值吻合较好．     

丙烯──甲醇──水三元体系汽液相平衡测定

用静态平衡釜法测定了丙烯-水-甲醇三元物系在30～60℃温度,0.3～0.9MPa压力下,其中甲醇-水比例为9:1、8:2、7:3时的汽液平衡数据,用UNIQUAC-RK模型方程对汽液平衡数据进行了关联,求得各模型参数,所得结果令人满意。     

A GROUP-INTERACTION CONTRIBUTION APPROACH. A NEW STRATEGY FOR THE ESTIMATION OF PHYSICO-CHEMICAL PROPERTIES OF BRANCHED ISOMERS

The methods based on the Group Contribution Concept usually fail when one attempts to estimate the physico-chemical properties of different branched isomers of a given compound. We present a new concept, the Group-Interaction Contribution Approach (GIC) which considers the contribution of the different interactions between groups present in a molecule instead of the contribution of structural groups.

This approach allows differentiation between branched isomers, thus leading to different values of the physico-chemical properties. The GIC Approach can be easily implemented in current correlations based on the group contribution concept.

The estimates of enthalpy of formation, normal boiling temperature and critical temperature of a series of 51 saturated hydrocarbons showed clearly that the GIC concept leads to very good estimations for branched isomers.     

二氧化碳在稠油中溶解度的测定与模型预测

选取华东地区某油田的稠油作为研究对象,采用静态高压相平衡装置,在温度363.15、368.15、373.15 K下,测定了压力2~22 MPa 范围内CO₂-稠油体系的气液两相的平衡组成。将稠油看作假一元组分,通过基团贡献法估算了稠油的临界参数,分别采用P-R 方程和改进的P-T 方程拟合关联所测得的实验数据,得到了CO₂-稠油体系的二元作用参数,最后计算了CO₂-稠油体系的相平衡数据,结果表明改进的P-T 方程的拟合结果要明显优于P-R 方程,更适用于高温高压下CO₂-稠油体系溶解度的数据预测。     

一异丙醇胺-二异丙醇胺-水体系汽液平衡预测和推算

主要利用UNIFAC基团贡献法预测一异丙醇胺-二异丙醇胺-水三元体系的汽液平衡数据,同时又根据UNIQUAC二元模型参数推算上述三元体系的汽液平衡。预测值和推算值分别与实验测定的一异丙醇胺-二异丙醇胺-水三元体系在338、353、368 K下的恒温汽液平衡数据进行比较,三者符合良好,为该三元体系平衡数据的获得提供了又一途径。     

用修正的UNIFAC模型参数及HVOS规则预测汽液平衡

利用Orbey和Sandler提出的HVOS混合规则,PR状态方程与Larsen的活度系数模型相结合建立了无限压力下汽液平衡模型,模型给定状态方程中不随温度变化的参数C*=-0.623 23。用大量的汽液平衡数据在广泛的温度范围内修正了12组MLUNIFAC基团相互作用参数,并用修正的和原始的参数分别对含醇、酸、酮、水、腈和胺等极性二元体系进行了预测。结果表明,体系预测精度显著提高,大部分体系汽相组成的绝对偏差低于4.00×10-2,压力的相对偏差低于6.00%。     

Application of UNIFAC to vegetable oil-alkane mixtures

The prediction of the vapor-liquid equilibria of vegetable oil-hexane mixtures is studied. Activity coefficients are calculated by the UNIFAC model. Different entropic contributions to activity coefficients from the literature are analyzed. These modifications improve the performance of the original UNIFAC model in vapor-liquid equilibrium calculations.     

A GE/Equation of State Mixing Rule for Vapor-Liquid Equilibria

A new excess Gibbs free energy/equation of state type mixing 0rule was derived byremoving the infinite pressure boundary condition imposed by Wong and Sandler.The mixing rulewas extensively tested in terms of a comprehensive data base,consisting of 52 simple nonpolar-nonpolar,carbon dioxide containing,hydrocarbon-hydrocarbon,CFC,polar-polar,nonpolar-polarbinary and multicomponent systems.Focused on the complete predictive capability,a comparisonbetween the Wong-Sandler and the mixing rule proposed was conducted.The results indicate that thenew mixing rule is in general superior to the Wong-Sandler's,and the binary interaction parameteras required by the latter is removed,which reduces computing effort and is reliable in predictions ofvapor-liquid equilibria from low pressures to high pressures.     

噻吩-正辛烷体系等压汽液相平衡研究

利用双循环汽液平衡釜测定101.3 kPa下噻吩-正辛烷体系的汽液相平衡数据.运用该实验结果,进一步获得组分的液相活度系数.实验数据经Herington方法检验,表明符合热力学一致性.采用二元体系UNIQUAC模型对该实验数据进行关联,采用最小二乘法拟合得到UNIQUAC模型参数.结果表明,噻吩在汽相组成的平均绝对偏差为0.0635,取得满意的效果.     

四氢呋喃-乙醇变压精馏分离

共沸混合物分离是化工过程中常见的分离难题。变压精馏是根据物系压力改变而使液体混合物共沸点组成发生变化,进而使共沸物系得以分离的一种有效分离方法。在热力学分析基础上,提出了四氢呋喃-乙醇液体混合物变压精馏分离双塔工艺流程。以NRTL-RK为物性计算方法,利用Aspen Plus模拟软件对变压精馏分离工艺过程进行分析及模拟,并对工艺参数进行优化。研究结果表明:在常压塔和0.8 MPa高压塔组成的双塔流程中变压精馏可将四氢呋喃-乙醇最低共沸混合物进行较好的分离。