萃取精馏制取无水乙醇过程不同节能方案的对比

Simulation and comparison of different energy saving schemes in extractive distillation process of ethanol-water system

以乙二醇为萃取剂从乙醇-水体系制取无水乙醇产品。基于流程模拟软件,对常规萃取精馏过程以及双效萃取精馏、分割式热泵萃取精馏、隔壁塔萃取精馏和内部热集成萃取精馏等4种节能工艺进行模拟及优化。设计规定如下:无水乙醇中乙醇质量分数不低于99.5%,回收的萃取剂中乙二醇质量分数不低于99.9%,废水中的质量分数为99.5%以上。在相同的设计基础和设计要求下,获得各流程最优的操作参数,并从节能效果及经济性分析对比4种节能工艺。结果显示:相比于常规萃取精馏过程,虽然内部热集成萃取精馏工艺可将能耗降低14.1%,节能效果最佳,但双效萃取精馏过程总成本最低,年均总成本可降低7.2%,是最具经济性的工艺过程。本研究为乙醇-水体系萃取精馏分离工艺的工业化提供了设计基础和理论依据。

Anhydrous ethanol was produced from the ethanol-water mixture using ethylene glycol as the extractant.Using the process simulation software,the conventional extractive distillation process and four different types of energy saving technologies were simulated and optimized,including double-effect distillation,vapor recompression distillation,dividing wall column distillation and internally heat integrated distillation.The design specification was as follows:the purity of ethanol should be no less than 99.5%,the purity of recovered ethylene glycol should be no less than 99.9%,and the purity of waste water should be greater than 99.5%.Under the same design basis and requirements,the optimum operating parameters of each process were obtained,and different processes were compared from the energy saving effect and economic analysis.The results revealed that although the internally heat integrated distillation technology was the most energy efficient process reducing the energy consumption by 14.1%compared with the conventional extractive distillation process,the most economic technology was double-effect extractive distillation process decreasing the total annual cost by 7.2%.This study provides the theoretical basis and design parameters for the industrialization of the extractive distillation process to produce anhydrous ethanol from the ethanol-water system.