Design and optimization of heat pump assisted reactive extractive distillation for separating benzene/n-propanol/water ternary azeotropes

In the chemical industry, wastewater often contains ternary azeotropic mixtures with multiple azeotropes, presenting challenges for separation due to their complex phase equilibrium. This work investigates the separation of a benzene/n-propanol/water mixture, which contains three binary azeotropes and one ternary azeotrope, using a reactive extractive distillation process. Firstly, the separation sequence is designed using ternary phase diagrams. Then, a multi-objective genetic algorithm is employed to optimize the total annual cost, CO2 emissions and extraction efficiency as objective functions. Subsequently, mechanical vapor recompression heat pump is designed for application in double column reactive extractive distillation process. Finally, feed preheating and heat exchanger network is designed for the heat pump assisted reactive extractive distillation process. The results indicate that the application of mechanical vapor recompression heat pump in the reactive extractive distillation process can significantly improve both economic and environmental performance. The double column reactive extractive distillation process, which is designed with heat pump, feed preheating and heat exchanger network, demonstrated optimal economic and environmental performance. Compared to conventional double column reactive extractive distillation processes, the total annual cost is reduced by 25.6%, and CO2 emissions is decreased by 52.0%. © 2024 Elsevier B.V.