乙酸异丙酯-异丙醇-DMSO的等压汽液相平衡和萃取精馏模拟

Vapor-Liquid Equilibria and Simulation of Extractive Distillation for Ternary Mixtures of Isopropyl Alcohol,Isopropyl Acetate and DMSO

在101.3 k Pa压力下,采用汽液平衡釜测定了二元物系异丙醇+二甲基亚砜(DMSO)、乙酸异丙酯+DMSO和三元物系异丙醇+乙酸异丙酯+DMSO的汽液平衡数据。利用Van Ness点校验法检验以上气液平衡数据,结果表明,数据符合热力学一致性。采用NRTL、Wilson和UNIQUAC活度系数模型对二元数据进行了拟合,并进行了三元物系汽液相平衡数据预测,结果表明,回归数据和实验数据吻合良好。Wilson模型的预测结果优于NRTL和UNIQUAC模型。一定量DMSO的加入可消除异丙醇和乙酸异丙酯的共沸点,因此,DMSO可作为一种有效的萃取剂来萃取精馏分离此二元物系。然后,通过流程模拟软件Aspen Plus,使用获得的二元交互作用参数对三元系统的萃取精馏进行了模拟。讨论了在不同的操作条件(塔板数、进料位置、溶剂比和回流比)下,异丙醇和乙酸异丙酯分离的情况,得到了最适宜的操作条件。

The vapor-liquid equilibrium （VLE） data for the binary system isopropyl alcohol＋dimethyl sulfoxide （DMSO）, isopropyl acetate＋DMSO and ternary system isopropyl alcohol＋isopropyl acetate＋DMSO were measured with a VLE modified Othmer still at 101.3 kPa. The experimental data were proved to be thermodynamically consistent when the point to point consistency test of Van Ness test was applied. The binary experimental data were correlated with the NRTL, Wilson and UNIQUAC activity coefficient models. Then, the ternary VLE data were predicted with the obtained binary interaction parameters. The results indicate that the calculated values are in good agreement with the experimental data. The results predicted by the Wilson models are slight better than those of other models. The binary azeotrope of isopropyl alcohol and isopropyl acetate was eliminated when added a certain amount of DMSO. Therefore, DMSO is a potential extractive agent to separate the azeotrope. Then, the extractive distillation of the ternary system was simulated using obtained binary interaction parameters with the process simulation software Aspen Plus. The separation conditions of isopropyl alcohol and isopropyl acetate with different operational parameters （stage number, feed stage, solvent ratio and reflux ratio） were discussed and the optimum conditions were achieved.