加盐NMP法萃取精馏分离裂解碳五馏分

利用Aspen Plus流程模拟软件,以含NaSCN的N-甲基吡咯烷酮(NMP)为萃取剂,对加盐NMP法萃取精馏分离裂解碳五馏分(C5)的过程进行模拟计算。考察了萃取剂中盐含量、萃取剂进塔温度、回流比及萃取剂与C5进料的质量比(溶剂比)等因素对分离效果的影响。模拟结果表明,当萃取剂中NaSCN质量分数为2.17%、萃取剂进塔温度为40℃时,第一萃取精馏塔需要的理论塔板数由未加盐时的80块减少到60块,溶剂比由3.45降到1.77;当第二萃取精馏塔在回流比为2,需要的理论板数由未加盐时的120块减少到92块,溶剂比由7.90降到7.76;采用加盐NMP法萃取精馏分离C5,异戊二烯、双环戊二烯和间戊二烯的纯度分别为99.90%,98.90%,90.30%,收率分别为98.86%,94.99%,98.93%,比传统的二甲基甲酰胺法和NMP法均有所提高。

Separation of Cracking C5 Fraction Through Extractive Distillation with Added Salt N-Methyl Pyrrolidone

Extractive distillation with added salt N-methyl pyrrolidone(NMP)as extractant for separation of cracking C5 was simulated by using Aspen Plus software.Effects of NaSCN content in extractant,extractant temperature at the inlet,reflux ratio and mass ratio of extractant to C5 feed(solvent ratio)on the separation effect were investigated.When mass fraction of NaSCN in extractant was 2.17% and extractant temperature at the inlet was 40 ℃,compared with conventional extractive distillation without NaSCN additive,application of the added salt NMP method could reduce both theoretical plate number and solvent ratio of the first extractive distillation column from 80 to 60 and from 3.45 to 1.77 respectively,and decrease both theoretical plate number and solvent ratio of the second extractive distillation column from 120 to 92 and from 7.90 to 7.76 respectively.At the same time recoveries of isoprene,dicyclopentadiene and 1,3-pentadiene could reach 98.86%,94.99% and 98.93% respectively,and their purities was 99.90%,98.90% and 90.30% respectively.The recoveries and purities were higher than those obtained by conventional dimethylformamide or NMP methods.