加压-常压与常压-加压变压精馏工艺分离甲醇-碳酸二甲酯的比较

Comparison of Pressurized Atmospheric and Atmospheric Pressure Variable Pressure Distillation Processes for Separating Methanol Dimethyl Carbonate

探讨了加压-常压与常压-加压两种变压精馏工艺对分离甲醇-碳酸二甲酯的影响。通过Aspen Plus模拟计算发现,在指定甲醇和碳酸二甲酯产品纯度的前提下,采用相同塔板数的高压塔和常压塔,两种工艺的能耗有显著差别;加压-常压工艺比常压-加压工艺的再沸器负荷高20%以上,应该选用常压-加压工艺分离甲醇-碳酸二甲酯。在设计变压精馏系统时,如若改变高压塔和低压塔次序能实现共沸物的分离,需要对两种工艺进行能耗或经济性分析,选取更优的工艺。

This article explores the effects of two pressure swing distillation processes,pressure-atmospheric and atmospheric-pressure,on the separation of methanol dimethyl carbonate.Through Aspen Plus simulation calculations,it was found that under the premise of specifying the purity of methanol and dimethyl carbonate products,there is a significant difference in energy consumption between high-pressure and atmospheric-pressure towers with the same number of trays;the reboiler load of the pressure-atmospheric process is more than 20%higher than that of the atmospheric-pressure process.Therefore,the atmospheric-pressure process should be used to separate methanol dimethyl carbonate.When designing a pressure swing distillation system,if changing the order of the high-pressure and low-pressure towers can achieve the separation of azeotropes,it is necessary to conduct energy consumption or economic analysis on the two processes and select the more optimal one.