甘油萃取精馏制取无水异丙醇的过程模拟

Simulation of isopropanol dehydration via extractive distillation using glycerol as entrainer

采用甘油作为萃取剂,基于NRTL活度系数模型,通过Aspen Plus软件对水-异丙醇共沸体系进行了萃取精馏过程模拟研究,在给定分离对象和分离要求的情况下进行操作参数优化,最终获得的操作参数为:精馏塔塔板数20块,水-异丙醇共沸体系的进料位置为第13块塔板,萃取剂的进料位置为第2块塔板,回流比为0.3,馏出率为0.87;闪蒸罐操作压力为15 k Pa,温度为130℃;汽提塔塔板数为12块,空气流量为75 000 kg/h。此时异丙醇质量分数达到了99.74%,回收率为99.74%;甘油回收的质量分数为99.90%,回收率是99.33%;精馏塔能耗为2 579.2 k W,闪蒸罐能耗为343.6 k W,总能耗为2 922.8 k W。

Process simulation and optimization of extractive distillation for preparation of anhydrous isopropanol using glycerol as entrainer are studied through Aspen Plus software based on NRTL activity coefficients model. The result show that when the separation requirements are reached,the operation parameters are as follows： 20 of stage number of extractive distillation column,13 of the number of feed stage,3 of the number of extractant stage,0. 3 of reflux ratio,0. 87 of the distillate yield,0. 15 k Pa of pressure and 130℃ of temperature for flash,12 of stage number of stripping column and 75 000 kg·h^（-1） of air flow rate for stripping. Under the optimal condition,the mass fraction of isopropanol and extractant can reach 99. 74% and 99. 9%,respectively. The recovery rate of isopropanol and extractant can each reach99. 74% and 99. 33%,respectively. The energy consumption of extractive distillation column is 2 579. 2 k W and that of flash tank is 343. 6 k W.