Design and multi-objective optimization of novel side-stream reactive-extractive distillation process with intermediate reboiler for recovering ethanol and 1,4-dioxane from wastewater

Abstract

Conventional distillation methods cannot separate ternary mixtures containing multiple azeotropes. This article designs two reaction distillation processes to recovery ethanol and 1,4-dioxane from wastewater, and a novel side-stream reactive-extractive distillation process with intermediate reboiler (SREDIR) process for the first time is proposed to separate this mixture. Taking economy and entropy generation as objective functions, multi-objective genetic algorithm is used to optimize the processes. It is concluded that all the proposed reaction distillation processes are energy-saving than the existing extractive distillation process for recoverying ethanol and 1,4-dioxane from wastewater. This existing process is an indirect extractive distillation process with DMSO as entrainer with heat integration (IED-DMSO-HI) process. Compared with IED-DMSO-HI process, the SREDIR process is economic since its total annual cost is reduced by 64.30%. However, the total entropy generation of SREDIR process is increased by 16.06%. Therefore, if there are high thermodynamic requirements for the separation process, reactive distillation requires careful consideration.