基于分壁式精馏塔的甲醇-碳酸二甲酯分离新工艺研究

Study on new separation process of methanol and dimethyl carbonate by extractive dividing wall column

提出了利用分壁式萃取精馏塔分离甲醇-碳酸二甲酯共沸物的新工艺,分析并建立了分壁式萃取精馏塔的热力学等效模型,利用Aspen Plus对该塔进行模拟和参数优化。主塔理论板数为36块,侧线精馏段理论板数为5块,隔板底端在主塔第27块塔板上,原料进料在第15块板,萃取剂进料在第3块板,回流比为1.2,溶剂比为1.2,在此参数下对分壁式萃取精馏塔进行严格模拟,可得到质量分数99.58%的碳酸二甲酯和99.82%的甲醇,回收萃取剂的质量分数可达到100%。与常规萃取精馏工艺相比,再沸器热负荷降低16.01%,冷凝器热负荷降低13.47%。

A new separation process of methanol and dimethyl carbonate by extractive dividing wall column is put forward. Thermodynamical equivalent process of extractive dividing wall column is analyzed and established. Simulation and optimization for extractive dividing wall column are conducted. The results are as follows：36 of main column theoretical plate number ,5 of side rectification section ,bottom of dividing wall placed at 27 stage of main column, 15 of feed stage,3 of extractant feed stage, 1.2 of reflux ratio and 1.2 of ratio of solvent to feed. Under this condition, rigorous simulation of extractive dividing wall column is carried out. Mass fraction of products is 99. 58% for dimethyl carbonate and 99.82% for methanol. The extractant can be 100% recovered. Compared with conventional extractive distillation process ,reboiler duty saving of extractive dividing wall column is 16. 01% and condenser duty saving is 13.47%.