正戊烷-正戊烯萃取精馏过程模拟计算

SIMULATION OF n-PENTANE AND 1-PENTENE EXTRACTIVE DISTILLATION PROCESS

随着乙烯工业的不断发展,对其副产物裂解C 5馏分进行分离利用以提高C 5馏分的附加值成为未来发展的趋势。以正戊烷-正戊烯体系为例,使用常见的3种萃取剂乙腈、甲乙酮和N-甲基吡咯烷酮对其进行萃取精馏过程模拟计算,在规定纯度(质量分数不小于95%)与回收率(不小于90%)的条件下对不同萃取剂模拟能耗进行了对比,建立了相应的数学模型,进行了萃取过程的分析与优化,进一步考察了塔板数、原料和萃取剂进料位置、操作回流比、萃取剂用量等因素的影响。结果表明,使用N-甲基吡咯烷酮作为萃取剂更为合理,优化的操作条件为:理论塔板数65块,原料与萃取剂进料位置分别在第45块和第5块塔板处,回流比3.7,萃取剂流量1030 kg/h。在该条件下,所得正戊烷纯度在95%以上,回收率大于91%。

With the continuous development of ethylene industry,the separation and utilization of by-product cracking C 5 component to improve the added value of C 5 has become the trend of development in the future.Taking n-pentane 1-pentene system as an example,the extractive distillation process of n-pentane 1-pentene system was simulated using three common extractants,such as acetonitrile,N-methylpyrrolidone and 2-butanone,the simulated energy consumption of different extractants was compared under the conditions of specified purity(≥95%)and recovery(≥90%),the corresponding mathematical model was established,and the extraction process was analyzed and optimized.The effects of other factors such as the number of trays,reflux ratio,feed position and extractant dosage were further optimized.The results showed that N-methylpyrrolidone was more reasonable as extractant.The optimized operation conditions were as follows:the number of theoretical trays was 65,the feeding positions of raw materials and extractants were at the 45 th and 5 th trays respectively,the reflux ratio was 3.7,and the extractant flow rate was 1030 kg/h.Under these conditions,the purity of n-pentane was over 95%,and the recovery was over 91%.