Side-stream extractive distillation is extensively employed to separate azeotropic mixtures since its energy-efficient benefits. Nevertheless, its economic effect is not always obvious due to the introduction of expensive high-pressure steam. In this article, a conventional triple-column extractive distillation process is firstly researched for separating n-hexane/ethyl acetate/acetonitrile mixture. To effectively decrease the requirement for high-pressure steam and achieve a reduction in economic costs of side-stream extractive distillation, three innovative side-stream extractive distillation processes with intermediate reboiler are proposed. A multi-objective genetic method is applied to optimize the four processes with total annual cost (TAC) and entropy production as two objective functions. Additionally, due to the presence of intermediate reboiler, heat integration design is implemented to the three side-stream extractive distillation processes with intermediate reboiler. Compared to the triple-column extractive distillation process, the heat integration of the three side-stream extractive distillation processes with intermediate reboiler exhibit better performance considering economy, energy-efficient, and entropy production. It indicates that the heat integration of the double side-stream extractive distillation process with intermediate reboiler can reduce 20.10% of TAC, 29.65% of energy consumption, and 35.63% of entropy production, respectively.

中文翻译：

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基于多目标优化的中间再沸器分离多共沸物侧流萃取精馏新工艺节能设计


侧流萃取蒸馏因其节能优势而被广泛用于分离共沸混合物。然而，由于引入昂贵的高压蒸汽，其经济效果并不总是明显。本文首先研究了传统的三塔萃取精馏工艺用于分离正己烷/乙酸乙酯/乙腈混合物。为了有效降低对高压蒸汽的需求，降低侧流萃取精馏的经济成本，提出了三种带有中间再沸器的创新侧流萃取精馏工艺。采用多目标遗传方法以年总成本（TAC）和熵产生作为两个目标函数来优化四个过程。另外，由于中间再沸器的存在，对带有中间再沸器的三个侧流萃取精馏工艺进行了热集成设计。与三塔萃取精馏工艺相比，三个侧流萃取精馏工艺与中间再沸器的热集成在经济性、节能性和熵产方面表现出更好的性能。结果表明，双侧流萃取精馏工艺与中间再沸器的热集成可分别减少TAC 20.10%、能耗29.65%、熵产35.63%。