乙腈法萃取精馏分离丁烯工艺研究
Butene Extractive Distillation Process by Acetonitrile

针对乙腈(ACN)法萃取精馏C4中丁烯的工艺存在较多不确定因素, 对其分离过程的影响因素进行了详细研究．采用ProⅡ对ACN法丁烯萃取精馏工艺进行模拟, 利用ACN法丁烯萃取精馏实验数据对流程模拟中的热力学模型进行修正, 对比发现模拟数据与实验数据吻合较好, 相对误差小于7.5% ．通过萃取精馏实验研究了理论板数、溶剂比、回流比、压力和溶剂中聚合物、水含量等因素对萃取精馏工艺的影响, 结合流程模拟数据, 得出了ACN法丁烯萃取精馏适宜的工艺条件：理论板数85～95, 溶剂比为10～12, 回流比为2.5～3.0, 操作压力为表压400～500 kPa, 溶剂中聚合物质量分数小于0.5% 、适宜水质量分数为5.0% ～6.0% ．在优化的工艺条件下, 塔釜烷烃质量分数低于0.5% , 塔顶烯烃质量分数低于0.9% , 烯烃的收率达到95% 以上．
Inflences on separation of the butene from C4 by extractive distillation with acetonitrile was studied because of many uncertain factors in the process. ProⅡ software was used to simulate the butene extractive distillation process by acetonitrile, and thermodynamic model was revised. It was found by comparison that the simulated results match well with experiment results with a relative error of less than 7.5%. The effects of some related parameters were analyzed systematically in the extractive distillation experiments, such as theoretical tray, extractant ratio, reflux ratio, pressure, and polymer and water concentrations in solvent. Combined with simulated data, the optimal processing parameters for separating the butene from C4 by acetonitrile were obtained, with the theoretical tray of 85―95, extractant ratio of 10―12, reflux ratio of 2.5―3.0, operating pressure of 400―500 kPa(G), optimum water content in solvent of 5.0%―6.0%(mass fraction) and polymer content in solvent being less than 0.5%(mass fraction). Under these circumstances, the alkane contents in the bottom product and the olefin content in the overhead product are lower than 0.5% and 0.9% , respectively, and the olefin yield can reach above 95%