Simulation and Optimization of Heat-integrated Pressure Swing Distillation for Separation of Methyl Acetate and Methanol
YANG Jin-bei YU Mei-qiong ZHENG Zhi-gong QIU Ting
Fuqing Branch, Fujian Normal University Fuqing Branch, Fujian Normal University CNOOC Shandong Chemical Engineering Co. Ltd, Jinan College of Chemistry and Chemical Engineering, Fuzhou University
Abstract：Heat-integrated pressure swing distillation for separation of methyl acetate and methanol was investigated based on the pressure-sensitivity of azeotropic composition. The separation process was simulated by Aspen Plus software using the thermodynamic model NRTL with binary parameters between two components obtained by experimental data of vapor liquid equilibrium (VLE). The influences of number of theoretical plates, feeding location and reflux ratio on the separation efficiency and energy consumption of high-pressure distillation and atmospheric distillation columns were analyzed. The results show that they are efficiently separated by heat-integrated pressure swing distillation, and the optimal conditions are as follows: for high-pressure column, the pressure is 909 kPa, number of theoretical plates 32, feeding location at the 21th plate, and reflux ratio 4.2, the purity of methyl acetate reaches 99.8% at the bottom of tower; for atmospheric pressure column, the pressure is 101 kPa, number of theoretical plates 30, feeding location at the 20th plate, and reflux ratio 4.6, the purity of methanol reaches 99.0% at the bottom of tower. The heat-integrated pressure swing distillation can save energy by 45.8% compared with conventional one, and the former is also more attractive than the extractive distillation using water as an entrainer for separation of azeotropic system.
2013, Vol. 13 
