Sensitivity Analysis and Rigorous Simulation of the Three-Phase Distillation Process of Ethanol/Ethyl Acetate/Water Mixture Based on Conceptual Design Principles

The three-phase distillation operation is one of the most advanced distillation methods for the separation of azeotropic mixtures. In this study, the optimization and rigorous design of the three-phase distillation process of the highly non-ideal mixture of ethanol/ethyl acetate/water was carried out based on conceptual design principles. Initially, the possibility of separating this highly complex mixture (at different concentrations) with four azeotropic points and three distillation regions was evaluated using different purification patterns. According to the results, it was determined that the second distillation region (the region where the stable component is ethanol) is the best one for the separation. Then, the effect of operating pressure and reflux ratio on the conceptual design of the three-phase column was investigated in the optimal distillation region. In the following, based on the conceptual design results, the rigorous simulation of the process was performed. Subsequently, the operational and design variables were optimized using the distinct and simultaneous sensitivity analysis methods. Based on optimized values, ethanol with a purity of 98.7 mol% was separated with a duty of 4754.14 kW. Finally, with the rigorous design of the column, it was revealed that to reach the mentioned purity, the packed columns with Mellapak 64x packing are smaller in size than the tray columns with sieve trays.