萃取精馏分离苯/环己烷共沸体系模拟与优化

以糠醛作为萃取剂分别使用常规萃取精馏、隔壁塔萃取精馏和差压热集成萃取精馏对苯和环己烷体系进行分离研究,使用流程模拟软件Aspen Plus V8.4进行模拟分析,对初步设计的三稳态流程,分别进行灵敏度分析,使用多目标遗传算法对过程进行整体优化以获得最优结构参数。结果表明,隔壁塔萃取精馏和差压热集成萃取精馏相对于常规萃取精馏所需再沸器热负荷可分别减小21.5%和15.7%。对三工艺流程进行经济性分析,发现与常规流程相比,隔壁塔萃取精馏的年总费用下降了6.0%,而差压热集成萃取精馏年总费用增加了50.8%,为萃取精馏分离苯/环己烷共沸体系工业化设计提供了理论依据和设计参考。

Simulation and optimization of extractive distillation for separation of azeotropic benzene/cyclohexane system

The separation of benzene and cyclohexane with furfural as entrainer was studied using conventional extractive distillation, extractive dividing wall column distillation and heat integrated pressure-swing extractive distillation. The three whole processes were simulated by commercial process simulator Aspen Plus V8.4. The sensitive analyses of all steady-state designs were carried out and the optimal flow sheets with minimum energy requirements have been established using the multi-objective genetic algorithm with constrains. Compared with the conventional configuration, the extractive dividing wall column distillation and heat integrated pressure-swing extractive distillation process with minimum heat duty of the reboiler presented the energy savings of 21.5% and 15.7%, respectively. The economic analysis was carried out to evaluate the economic feasibility of the three processes. The results clearly demonstrated that when compared with the conventional extractive distillation process, the total annual cost was reduced by 6.0% in the extractive dividing wall column and increased by 50.8% in the heat integrated pressure-swing extractive distillation, which provided a theory basis and design reference for the industrial design for extractive distillation process to separate azeotropic benzene and cyclohexane system.