萃取精馏分离乙醇-甲苯共沸体系的模拟与优化

Simulation and optimization of extractive distillation for ethanol-toluene azeotropic mixture

利用化工流程模拟软件,选用Wilson模型作为气液平衡的计算模型,对萃取精馏分离乙醇-甲苯共沸物的过程进行模拟研究。考察不同溶剂对乙醇一甲苯相对挥发度的影响,筛选出适宜的溶剂为正丙苯。对溶剂和原料的进料位置、溶剂比、回流比和溶剂进料温度对萃取精馏效果的影响进行了模拟分析。在保证产品乙醇、甲苯质量分数均在0.998以上的条件下,萃取精馏塔模拟优化结果为:全塔总理论板数35块,溶剂进料位置第16块塔板、原料进料位置第32块塔板、溶剂比1.2、回流比1.6、溶剂进料温度为常温。模拟结果可用于指导实际过程分析和设计。

An extractive distillation process with two columns and n-propylbenzene as the extractant for separating ethanol-toluene mixture was simulated by using process simulation software and Wilson model. After the different solvents were investigated the influence of ethanol-toluene relative volatility, selecting the suitable solvent for n-propylbenzene. The effects of feed-positions of the solvent and mixture, reflux ratio, solvent ratio and the solvent feed-temperature on the extractive distillation were studied. The optimum process parameters were obtained. Aimed at mass fraction of ethanol and toluene was above 0.998 in the products, the optimum process parameters were obtained, as follows solvent feeding position 16, ethanol and toluene mixture feeding-position 32, solvent ratio 1.2, reflux ratio 1.6 and the solvent feed-temperature about 30℃. The simulation results may be used to guide analysis and design of actual industrial plant.