萃取精馏分离甲醇和碳酸二甲酯二元共沸物

Separation of Azeotropic DMC-MEOH Mixture by Extractive Distillation

在对三塔萃取精馏分析的基础上,提出了以邻二甲苯为萃取剂,两塔分离甲醇和碳酸二甲酯共沸物的萃取精馏新流程.考察了进料配比、回流比等操作参数对萃取精馏性能的影响,并采用共沸和非共沸两种进料方式,考察了三塔体系和两塔体系在操作条件和分离性能上的差异.利用ASPEN软件对两种流程进行了优化分析和模拟放大研究.实验和模拟结果表明:两种分离流程均可实现甲醇与碳酸二甲酯的有效分离.两塔体系省去了一个塔,降低了设备费用,简化了操作,能量的消耗略有增加.考虑到低品位的能量容易取得以及萃取剂可以回收利用等因素,两塔体系具有较高的工业利用价值.

Analyzing the three-column system of extractive distillation, two-column system adopting o-xylene as an extraction agent for separation of azeotropic methanol-dimethyl carbonate mixture is developed. The influence of the operation parameters, such as the feed conditions, the reflux ratio and the extractant to feed ratio on the extractive distillation efficiency is investigated. The difference of separation capability between three-column system and two-column system is also investigated under the conditions of azeotropic feed and non-azeotropic feed. The simulation and optimization are carried out with ASPEN plus software. The results show that these two routes enable to realize separation of azeotropic DMC-MEOH mixture. Compared with three-column system, the device cost is reduced and the operation gets simplified, while the consumption of extractant and energy is slightly increased in the two-column system. Since the lower grade heat can be obtained easily and the extractant can be recycled, the two-column system shows a wider industrial foreground.