基于先进萃取精馏工艺的乙腈-水共沸物分离过程模拟

以甘油与乙二醇的混合溶剂(摩尔比为6∶1)为萃取剂，分别采用常规萃取精馏(CED)、减压萃取精馏(LPED)、隔壁塔萃取精馏(EDWC)和结合预浓缩段和溶剂回收段的萃取精馏(CPRED)等方法对乙腈 水体系进行精馏分离；并利用Aspen Plus软件对4种工艺流程进行稳态模拟，以年总费用(TAC)最小为目标，采用序贯模块法对各流程的工艺参数进行优化以获得最优结构参数。结果表明：与常规萃取精馏流程的TAC相比，减压萃取精馏的TAC下降了392%，结合预浓缩段和溶剂回收段的萃取精馏的TAC下降了10.57%，而隔壁塔萃取精馏的TAC增加了1003%；从环保角度分析，结合预浓缩段和溶剂回收段合成的萃取精馏流程CO2排放量最少，而隔壁塔萃取精馏流程CO2排放量最多。

Process Simulations on the Separation of Acetonitrile and Water Mixtures by Extractive Distillation

The separation of acetonitrile and water using the mixture of glycerol and ethylene glycol (n(glycerol)∶n(ethylene glycol)=6∶1) as extractant is studied by employing conventional extractive distillation (CED), low pressure extractive distillation (LPED), extractive dividing wall column distillation (EDWC), combining the preconcentration and recovery section in one column for extractive distillation (CPRED). The four processes were simulated and optimized by using Aspen Plus software, in which total annual cost (TAC) and a sequential iterative strategy were used to find the optimal extractive distillation systems. The results revealed that compared with the CED process, the TAC is reduced by 392% and 1057% in LPED and CPRED, while the TAC is increased by 1003% in EDWC. In addition, the EDWC emits the most amount of CO2 (974.46 kg/h), while the CPRED emits the least CO2 (73444 kg/h). Overall, the presented study provides a theory basis for the industrial design of extractive distillation process to separate acetonitrile and water mixture.