萃取精馏分离邻二甲苯-苯乙烯过程的模拟

Simulation of Separating o-Xylene-Styrene by Extractive Distillation

选用N-甲基吡咯烷酮作为萃取剂,采用Wilson模型作为气液平衡的计算模型,利用化工流程模拟软件,对萃取精馏分离邻二甲苯-苯乙烯的过程进行模拟。考察了溶剂和原料的进料位置、萃取剂与原料的质量比(溶剂比)、回流比和理论塔板数对苯乙烯回收率和萃取精馏塔塔釜热负荷的影响,并通过正交实验设计得到较优的精馏操作参数。在满足产品中苯乙烯含量为99%(w)的条件下,正交优化的结果为:溶剂进料位置第6块塔板、原料进料位置第72块塔板、溶剂比9、回流比8、理论塔板数140。在该条件下,苯乙烯回收率为95.46%,热负荷为4.611 7 GJ/h,综合评价最好。

An extractive distillation process with two columns and N-methyl pyrrolidone as the extractant for separating o-xylene-styrene mixture was simulated by using process simulation software and Wilson model. The effects of feeding positions of the solvent and mixture, reflux ratio, solvent ratio and theoretical plate number on the recovery rate of styrene and the thermal load of the reboiler were studied. The optimum process parameters were obtained by an orthogonal experiment design. Aimed at styrene mass fraction of 99% in the products, under the optimum process conditions of solvent feeding position 6^th, o-xylene-styrene mixture feeding position 72^nd, solvent ratio 9, reflux ratio 8 and theoretical plate number 140, the recovery rate and thermal load were 95.46% and 4.611 7 GJ/h, respectively.