四氢呋喃-甲醇-乙酸甲酯-水热集成双溶剂萃取精馏工艺

Heat integrated double solvent extractive distillation process of tetrahydrofuran-methanol-methyl acetate-water

针对四氢呋喃-甲醇-乙酸甲酯-水四元物系中存在多个二元共沸物的特点,本工作提出了常规双溶剂萃取和热集成双溶剂萃取两种精馏工艺。基于WILSON方程计算得到热力学数据,并对萃取剂进行了筛选。结果表明,对于四氢呋喃-甲醇和乙酸甲酯-甲醇共沸物系,选用水作为萃取剂最为合适;而对于四氢呋喃-水和乙酸甲酯-水共沸物系,则选用乙二醇作为萃取剂最为合适,且总溶剂比为0.65,乙二醇和水的比例为1.3。在此基础上,以能耗和年总费用(TAC)作为精馏工艺的评价指标,对提出的常规双溶剂萃取和热集成双溶剂萃取精馏工艺进行了模拟,并利用夹点分析技术对双溶剂萃取精馏系统的换热网络进行了优化。研究结果表明,优化后的换热网络其冷公用工程消耗降低44.12%,热公用工程消耗节约42.49%。与常规双溶剂萃取精馏工艺相比,热集成双溶剂萃取精馏工艺其能耗降低约43.29%,节省TAC约26.89%,热力学效率提高了3.25%。可见,热集成双溶剂萃取精馏工艺用于分离以上四元共沸物系,具有较好的技术经济优势。

According to the characteristics of multiple binary azeotropes in the tetrahydrofuran-methanol-methyl acetate-water quaternary system, two distillation processes, conventional double solvent extractive distillation, and heat integrated double solvent extractive distillation were proposed. The solvent was selected based on the thermodynamic data calculated by the WILSON equation. The results showed that water was the most suitable solvent for tetrahydrofuran-methanol and methyl acetate-methanol azeotropes, and ethylene glycol was the most suitable solvent for tetrahydrofuran-water and methyl acetate-water azeotropes, the total solvent ratio was 0.65 and the ratio of ethylene glycol to water was 1.3. On this basis, taking energy consumption and total annual cost(TAC) as the evaluation indexes of the distillation process, the proposed conventional double solvent extractive distillation and heat integrated double solvent extractive distillation were simulated. The heat exchange network of the double solvent extractive distillation system was optimized by pinch analysis technology. The results showed that the cold utility consumption of the optimized heat exchange network was reduced by 44.12%, and the heat utility consumption was saved by 42.49%. Compared with the conventional double solvent extractive distillation process, the energy consumption of heat integrated double solvent extractive distillation process was reduced by about 43.29%, TAC was saved by approximately 26.89%, and the thermodynamic efficiency was increased by 3.25%. It can be seen that the heat-integrated double solvent extractive distillation process has better technical and economic advantages for separating the above quaternary system.