Design and control of an energy-efficient triple-column pressure swing distillation configuration for separation of acetone-methanol-hexane mixture

Although several studies on the design of ternary mixtures with multiple binary azeotropes can be easily found in the existing literature, there are only a few recent design studies dealing with ternary mixtures including both binary and ternary azeotropes. In this study, two alternative triple-column pressure swing distillation (PSD) configurations are proposed for acetone-methanol-hexane mixture including three binary and one ternary minimum boiling homogeneous azeotropes. They are compared based on total annual cost by analyzing ternary maps at different pressures. Results show that methanol-acetone-hexane (M-A-H) separation sequence obtained by a column configuration operating at 0.5, 1 and 5 bar has a better economic performance compared to acetone-methanol-hexane (A-M-H) separation sequence. Moreover, the fully heat-integrated M-A-H configuration results in a further saving of 13.8%. Furthermore, the plantwide control structure of the heat-integrated M-A-H configuration including a pressure-compensated temperature controller shows a good performance against disturbances in feed flowrate and composition.