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    热集成及热泵强化低共熔溶剂萃取精馏分离异丙醇-水

    Heat integration and heat pump intensified extractive distillation for isopropanol-water separation using deep eutectic solvents as entrainer

    • 摘要: 低共熔溶剂(DESs)作为一种新型环境友好溶剂,在萃取精馏中展现出巨大潜力。通过Aspen Plus流程模拟软件设计并优化了以DESs(氯化胆碱/三甘醇,物质的量比为1∶3)为萃取剂的异丙醇-水萃取精馏分离工艺。以年度总费用(TAC)最小为目标,采用序贯迭代法对进料位置、萃取剂用量、萃取剂温度、理论板数和回流比进行优化。模拟结果表明,与以传统溶剂乙二醇(EG)为萃取剂的工艺相比,该工艺所需的塔板数、回流比显著减小,TAC可降低20.95%。为进一步挖掘节能潜力,构建了结合热集成与热泵的两种强化工艺。全面的对比分析表明,热集成-热泵辅助萃取精馏工艺较以EG为萃取剂的传统工艺的能耗、TAC及有效能损失分别降低了46.35%、31.10% 和39.33%。DESs在经济性与环境友好性方面展现出替代传统萃取剂的潜力。

       

      Abstract: As a new type of environment-friendly solvent, deep eutectic solvents (DESs) have great potential in extractive distillation. In this study, the separation of isopropanol and water by extractive distillation using DESs (ChCl/TEG, molar ratio was 1∶3) as entrainer was designed and optimized by Aspen Plus. Targeting minimization of total annual cost (TAC), sequential iterative optimization was applied to key variables including feed stage location, entrainer flow rate, entrainer temperature, number of theoretical stages, and reflux ratio. Compared with the process using traditional solvent ethylene glycol (EG) as entrainer, the proposed process required significantly fewer theoretical stages and lower reflux ratio, reducing TAC by 20.95%. To achieve further energy saving, two processes combined with heat integration and heat pump were established. A comprehensive comparative analysis demonstrated that the heat integration and heat pump intensified extractive distillation process achieves significant reductions of 46.35% in energy consumption, 31.10% in TAC, and 39.33% in exergy loss compared to the conventional process using EG as the solvent. The results indicate that DESs exhibit considerable potential to replace conventional solvents due to their superior economic and environmental benefits.

       

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