Novel heat pump and heat integration assisted pressure swing distillation for separating methyl cyclohexane and n-butyl alcohol to save energy and reduce CO2 emissions

Aiming at the problem of high investment and energy consumption in separating the azeotropes, the feasibility and economy of pressure swing distillation processes combined with heat integration and heat pump technology for separating methylcyclohexane and n-butanol alcohol mixture were analyzed and discussed. The CO2 emissions, total annual cost and energy consumption are used as the evaluation indicators to assess the three modified pressure swing distillation processes. To obtain the optimal operation parameters of processes, the sequential iterative program is designed, which aims at the minimum total annual cost. In this work, heat integration pressure swing distillation and heat pump pressure swing distillation processes are compared with conventional pressure swing distillation in economic, energy-saving and ecological performance. The results show that the modified processes, whether heat integration pressure swing distillation or heat pump pressure swing distillation, significantly improves the economy and energy efficiency. Compared to the conventional pressure swing distillation process, the heat integration pressure swing distillation process can reduce CO2 emissions by 32.99%, total energy consumption by 32.99% and total annual cost by 23.61%. The heat pump pressure swing distillation process has the optimal economy and the least energy consumption among the three separation processes, which can reduce the total annual cost by 44.03%, the total energy consumption by 54.27% and the CO2 emission by 89.98%.