变压精馏分离甲醇-苯体系的模拟与优化

Simulation and optimization of the pressure-swing distillation for methanol-benzene separation

基于甲醇-苯二元共沸体系的压力敏感性,利用Aspen Plus软件对变压精馏(PSD)分离甲醇-苯工艺进行模拟与优化。采用序贯迭代法,以年度总费用(TAC)最小为目标函数,确定了最佳工艺条件:低压塔理论板数19,原料进料位置为第12块塔板,回流板位置为第9块板,回流比0.7;高压塔理论板数21,进料位置第14块塔板,回流比1,所得甲醇和苯产品纯度均达到了99.9%。同时,探究了变压精馏分离甲醇-苯工艺的部分热集成方案,与传统变压精馏相比可节能42.7%,可为甲醇-苯分离的实验研究及其他共沸体系的分离提供参考。

Both methanol and benzene as important organic solvents am widely used in paints, coatings, phamlaceutical and other fields. Based on the pressire-sensitive of the mixture of methanol-benzene, the process of separating this azeotropic system via pressure-swing distillation （PSD）is simulated by Aspen Plus. The process is optimized by sequential iterative method which takes the minimum total annual cost （TAC） as the objective function, and the optimum process parameters are detemfined： for low pressure column, theoretical plate number 19, feed plate 12th and reflux ratio 0.7 ; for high pressire column, theoretical plate number 21, feed plate 14th and reflux ratio 1.0. The purity of the methanol and benzene obtained 99.9%. Meanwhile, the partial heat integration schemes of methanol-benzene process via pressure swing distillation have been explored, and the results show that it can reduce the energy consumption by 42.7% compared with the conventional pressure swing distillation. And those results provide a reference for the further experimental study of the separation of methanol benzene and the other systems.