以NMP为萃取剂,对正己烷-甲基环戊烷共沸物体系进行分离研究。提出了传统双塔萃取精馏耦合成隔壁塔的新工艺。选取了常规的2组分双塔萃取精馏流程(ED)和隔壁萃取精馏(EDWC)流程,对共沸体系进行了分离研究。借助改进非支配排序遗传算法(NSGA-Ⅱ)对稳态工艺进行优化设计,以年总费用(TAC)与二氧化碳排放量($E_{\text{CO}_2}$)为目标变量,进行多目标参数优化。结果表明,各操作变量之间耦合性高。2个目标变量呈一定的竞争关系,随着二氧化碳排放量的增加,TAC在逐步降低。当优化至200代时,目标变量年总费用TAC与二氧化碳排放量$E_{\text{CO}_2}$基本稳定不发生变化,选取了第200代中TAC最小的一组Pareto最优前沿解作为优化后的最优解。与传统的双塔萃取精馏相比,萃取精馏隔壁塔节约TAC 6.72%,减少二氧化碳排放量4.56%,说明采用EDWC技术分离正己烷-甲基环戊烷是一种有效的节能降本方法。

Using NMP as an extractant,a separation study is conducted on the n-hexane/methylcyclopentane azeotropic system.A novel process coupling traditional dual-column extractive distillation into one dividing-wall column is proposed.Conventional dual-component dual-column extractive distillation process and dividing-wall column extractive distillation process are selected to study the separation of the azeotropic system.An improved non-dominated sorting genetic algorithm (NSGA-Ⅱ) is utilized to optimize and design the steady-state process,and the total annual cost (TAC) and carbon dioxide emission ($E_{\text{CO}_2}$) are taken as the objective variables for multi-objective parameter optimization.The results show that there are high coupling degrees among the operational variables,and there exists a competitive relationship between the two objective variables.As carbon dioxide emission increases,TAC decreases gradually.When the optimization reaches the 200th generation,both TAC and $E_{\text{CO}_2}$ become stable and change hardly.A set of Pareto optimal front solutions with the minimum TAC from the 200th generation is selected as the optimal solution after optimization.TAC of the dividing-wall column extractive distillation process is 6.72% less than that of the traditional dual-column extractive distillation process,and $E_{\text{CO}_2}$ is 4.56% less,demonstrating that using dividing-wall column extractive distillation process for the separation of n-hexane/methylcyclopentane is an effective method for energy saving and cost reduction.