Abstract:

In the industrial production process, ethyl acetate/ethanol/water ternary azeotropic system containing a large amount of water is often encountered. Extractive distillation is a common means to achieve effective separation of azeotropes. For the separation of ternary azeotropes with one large component content, the introduction of preconcentration can significantly improve the process economy. In this paper, conventional three-columns extractive distillation (TCED), four-columns extractive distillation with pre-separation (FCED), and three-columns extractive distillation process with one integrated distillation column with both preconcentration and solvent recovery functions (TCED-IDC) are established for the separation of ethyl acetate/ethanol/water ternary azeotropic systems containing large amounts of water. Following that, the processes proposed are optimized to minimize the total annual cost (TAC) by using genetic algorithms with penalty function. The economic optimization results shows that the TCED-IDC can save 27.1% of TAC and 29.7% of energy consumption compared with the conventional TCED process, and 9.9% of TAC and 13.0% of energy consumption compared with the FCED process considering preconcentration.

Key words: waste water, simulation, azeotrope, extractive distillation, preconcentration, solvent recovery

摘要：

在工业生产过程中经常遇到含有大量水的乙酸乙酯/乙醇/水三元共沸体系，萃取精馏是实现共沸物有效分离的常见手段。对于某一组分含量较大的三元共沸物的萃取精馏分离，预分离的引入能够显著提升过程经济性。针对含有大量水的乙酸乙酯/乙醇/水三元共沸体系的分离，建立了常规三塔萃取精馏、含有预分离的四塔萃取精馏以及预分离塔与萃取剂回收塔耦合的三塔萃取精馏流程，并以年度总费用（TAC）最小为优化目标采用考虑惩罚函数的遗传算法对各流程进行经济优化以获得最优的操作参数和经济费用。经济优化结果表明，预分离塔与萃取剂回收塔耦合的三塔萃取精馏流程与常规的三塔萃取精馏流程相比，可节省27.1%的TAC与29.7%的能量消耗。同时，与含有预分离的四塔萃取精馏流程相比，预分离与萃取剂回收功能的耦合可降低9.9%的TAC与13.0%的能量消耗。

关键词: 废水, 模拟, 共沸物, 萃取精馏, 预分离, 萃取剂回收