(85a) Internally Heat-Integrated Pressure-Swing Distillation for Non-Ideal Separation Using Computational Fluid Dynamics

This study presents the computational fluid dynamics (CFD) simulation to design internally heat-integrated pressure-swing distillation (HIPSD) systems with improved energy efficiency for azeotropic distillation. A pinch analysis was applied to determine the optimal operating pressure of the HIPSD in a double annular column configuration to achieve adequate heat transfer and circumvent distillation boundaries. To separate a highly azeotropic ternary mixture of butyl acetate, butanol, and water, a single unit of HIPSD and a decanter are employed. Different design alternatives are explored for various initial feed compositions. In each sequence, the CFD method was used to calculate the heat transfer rate inside the HIPSD, leading to a reduction of total utility consumption by 9.72% and 15.44%. The reboiler and condenser duty in the HIPSD were also reduced by up to 48.65%. Furthermore, the internal heat integration improves the separation efficiency in the condenser of the high-pressure column, allowing for zero reflux.