正、反向萃取精馏分离丙酮-甲醇体系的模拟研究

选择水、氯苯作为正、反向萃取剂来分离丙酮-甲醇共沸物系，规定原料液进料流率为540 kmol/h，进料温度为320 K，各塔的操作压力均为101.325 kPa，通过Aspen Plus进行流程模拟，得到摩尔分数为99.5%的产品。以最小全年总费用（TAC）为目标、序贯迭代搜索法为优化方法对不同萃取剂下的各塔进行灵敏度分析，规定塔顶轻组分摩尔分数为99.5%、摩尔回收率为99.99%，得到的优化结果显示：正向萃取中萃取精馏塔的理论塔板数、原料进料位置和萃取剂进料位置分别为76块、64块和45块，萃取剂回收塔的理论塔板数、进料位置分别为25块、14块；反向萃取中萃取精馏塔的理论塔板数、原料进料位置和萃取剂进料位置分别为52块、40块和24块，萃取剂回收塔的理论塔板数、进料位置分别为25块、7块。通过TAC计算表算出两种萃取剂下工艺流程所需的经济费用，结果为正向萃取流程费用26 658 942.69元/a，反向萃取流程费用25 466 172.02元/a。

Simulation of the separation of acetone-methanol systems by positive and reverse extractive distillation

Water and chlorobenzene have been employed as positive and reverse extractants to separate the acetone-methanol azeotrope system. It was stipulated that the feed rate of liquid raw material was 540 kmol/h, the feed temperature was 320 K, and the operating pressure of each tower was 101.325 kPa. Process simulation using Aspen Plus gave a product with a molar purity of 99.5%, and with the minimum total cost (TAC) as the goal, a sequential iterative search for the optimized sensitivity of the tower was carried out for different extraction solvents. The molar concentration of the light component at the top was 99.5% and Moore recovery was 99.99%. For positive extraction, the optimization results are theoretical plate number of the rectifying column of 76, with raw material feeding location at block 64 and extraction agent feeding location at block 45, and theoretical plate number of the extraction solvent recovery tower of 25 with feed position at block 14. For reverse extraction, the theoretical number of trays is 52, the feeding position of the raw materials is 40 and the feeding position of the extractant is 24, and the theoretical number of trays of the extractant recovery tower is 25 with feeding position of 7. TAC calculations were used to calculate the economic cost of the process for the two extraction agents. The results showed that the forward extraction process cost 26.66 million yuan/year and the reverse extraction process cost 25.47 million yuan/year.