乙酸甲酯-甲醇-水的热集成萃取精馏工艺

Heat integration extractive distillation process of methyl acetate-methanol-water

首先在50 kPa下用水萃取精馏分离乙酸甲酯、甲醇和水的混合物,得到了高质量分数的乙酸甲酯,之后利用普通精馏分离甲醇和水。使用热集成技术改造该工艺流程,将甲醇单塔精馏改造为并流双效精馏,两塔压力分别为101.325、500.000k Pa。同时采用高温水对萃取精馏塔两股进料预热,以降低萃取精馏塔塔釜的能耗。在操作参数单因素灵敏度分析的基础上,以系统塔釜总能耗及乙酸甲酯质量分数为目标函数,采用响应面方法优化操作参数。结果表明,热集成工艺较之前工艺节能23.43%。

Methyl acetate,methanol and water are separated by vacuum extractive distillation at 50 kPa in Aspen plus with NRTL method. Methyl acetate is obtained at the top of the column,while the mixture of methanol and water are transported to another distillation column. The heat integrated technology is then used to improve the utilization of energy. Thus the traditional methanol column is replaced by two parallel columns with operating pressure at 101. 325 kPa and 500 kPa. At the same time,the high temperature water from extractive distillation column is transported to preheat the feed and solvent streams to accomplish heat integration. Base on the results of single factor analysis,RSM（ response surface methodology） is used to optimize the system with the purity of methyl acetate and the total reboiler duties as functions. The results show that the heat integration process can save 23. 43% of reboiler duties.