Comparing and controlling of three batch distillation column configurations for separating tertiary zeotropic mixtures

Abstract

This paper concerns the simulation and control of multi-vessel batch distillation configurations for separating tertiary zeotropic mixtures. Three configurations, namely, conventional middle vessel, modified middle vessel and rectifier column were selected. Unlike the previous works, a detailed model without assumptions of constant level, pressure and boilup rate was used. This model was simulated in Aspen Hysys 2009 software. In addition, a control structure which has one pressure and one/two level controllers was selected for each configuration. The results indicate that the selected control structure has an acceptable performance and the modified middle vessel configuration needs the least batch time and energy consumption. Finally, the performances of level control and temperature control strategies were compared. The results show that the level control strategy has better dynamic performance and needs lower batch time, but with uncertain feed composition, the temperature control structure is preferred.