A computational study on the separation of acetonitrile and water azeotropic mixture using pressure swing distillation

In this study, a computational study has been performed to separate over 99.9 mol% of acetonitrile from binary azeotropic mixture of acetonitrile and water using a Pressure Swing Distillation process (PSD). The PSD process is used to separate azeotropic mixtures using the difference between the relative volatilities and azeotropic compositions by changing the system pressure. Non-Random Two Liquid (NRTL) model for liquid phase and the Peng-Robinson equation for vapor phase are used. An optimization study for the reflux ratio and feed stage locations which minimize the total reboiler heat duties are studied. Since the PSD process consists of two columns, i.e. high pressure (HP) and low pressure (LP), the effect of column sequences on the optimum process conditions is also reported.