萃取精馏和变压精馏分离苯-乙醇的模拟研究

Simulation Study on Separation of Benzene-Ethanol by Extractive Distillation and Pressure Swing Distillation

采用Aspen Plus化工流程模拟软件,通过NRTL热力学模型,分别进行苯和乙醇混合物的萃取精馏和变压精馏分离模拟研究。萃取精馏采用丙三醇为萃取剂,萃取精馏塔以33为理论塔板数、28为混合物进料位置、2为萃取剂进料位置、1.1为回流比、3.0为溶剂比(萃取剂用量与混合物进料量比值);溶剂回收塔以5为理论塔板数、3为进料位置、1.0为回流比时,分离得到苯和乙醇的质量分数均为99.62%。变压精馏由常压塔(101.325 kPa)和高压塔(520 kPa)串联而成,常压塔以18为理论塔板数、8为进料位置、3.0为回流比;高压塔以16为理论塔板数、10为进料位置、3.0为回流比时,可得到乙醇和苯质量分数分别为99.52%和99.01%。

The extractive distillation and pressure swing distillation separation of benzene and ethanol mixture were studied by NRTL thermodynamic model using Aspen Plus chemical process simulation software,respectively.Glycerol was used as the extractant for extractive distillation.In the extractive distillation column,33 was the theoretical plate number,28 was the feed position of the mixture,2 was the feed position of the extractant,1.1 was the reflux ratio,and 3.0 was the solvent ratio(the ratio of the amount of the extractant to the amount of the mixture).In the solvent recovery column,5 was the theoretical plate number,3 was the feed position,and 1.0 was the reflux ratio.The mass fractions of benzene and ethanol obtained through separation were both 99.62%.The pressure swing distillation was composed of the atmospheric tower(101.325 kPa)and the high-pressure tower(520 kPa)in series.In the atmospheric tower,18 was the theoretical plate number,8 was the feed position,and 3.0 was the reflux ratio.In the high-pressure tower,16 was the theoretical plate number,10 was the feed position,and 3.0 was the reflux ratio.The mass fractions of ethanol and benzene were obtained as 99.52%and 99.01%,respectively.