碳酸丙烯酯与1,2-丙二醇二元体系UNIQUAC模型参数的估算与实验修正

Estimation and Experimental Modification of UNIQUAC Model Parameters for the PC and PG Binary System

在碳酸二甲酯的转酯化工艺过程模拟、设计与优化研究中,缺少与碳酸丙烯酯(PC)和1,2-丙二醇(PG)二元体系相关的相平衡实验数据及UNIQUAC模型参数。今通过实验数据推算和基团贡献法估算两种方法进行了PC和PG二元体系的UNIQUAC模型参数的估算;利用自行设计的汽液平衡装置实验测定了该二元体系的常压汽液平衡数据,通过绘制T-x-y曲线对比对估算结果的准确性进行验证,结果显示实验数据推算办法获得的UNIQUAC模型参数精度较高;最后借助流程模拟软件Aspen Plus,通过数据回归对该二元体系的UNIQUAC模型参数进行了修正,使用修正后的UNIQUAC模型参数对PC和PG二元体系汽液平衡的温度、液相PC摩尔分数和气相PC摩尔分数计算的平均绝对偏差分别是0.5、0.0124%和2.3035%,表明修正后的UNIQUAC模型参数能够用于高精度要求的工艺过程模拟计算。

When conducting simulating, designing and optimizing a DMC transesterification process, thevapor-liquid equilibrium （VLE） data and UNIQUAC model parameters for the binary system of propylenecarbonate （PC） and 1,2-propylene glycol （PG） are needed. However they usually cannot be found normally. Inthis paper, the UNIQUAC model parameters were estimated by two available methods, they are theexperimental data calculation and UNIFAC based estimation. The isobaric VLE data of the PC and PG binarysystem under atmospheric pressure were determined in a specially designed VLE experimental device. Theaccuracy of the estimated results was verified by T-x-y plots and the verified results show that the accuracy ofUNIQUAC model parameters obtained by experiment data calculation is higher. Finally, the UNIQUAC modelparameters were modified by data regression with using simulation system of Aspen Plus. The calculated valuesagree well with the experimental results, and the average absolute deviations of the predicted temperature, PCvapor mole fraction and PC liquid mole fraction are 0.5, 0.0124 % and 2.3035 %, respectively. The modifiedUNIQUAC model parameters can be used in relevant process simulations with high accuracy requirement.