Energy-efficient extractive pressure-swing distillation with integrated preconcentration column and natural decanter for ternary heterogeneous mixtures

This study proposes novel processes for the separation of ternary heterogeneous mixtures by incorporating a natural decanter into the intensified extractive distillation process with integrated preconcentration column (IED-IPC). The proposed method is demonstrated through two case studies: water/benzene/isopropanol and water/ethyl acetate /methanol, categorized as Serafimov's class 2.0-2b and 3.1–2, respectively. Thermodynamic analysis is conducted to illustrate the theoretical benefits of integrating the natural decanter into the IED-IPC and reducing operating pressure is preferred. Correspondingly, the heterogeneous azeotropic-assisted IED (i.e., HAIED-IPC) and pressure-swing enhanced HAIED-IPC (i.e., HAIEPSD-IPC) processes are developed. Next, the rigorous optimization is conducted by parallel genetic algorithms followed by economic and environmental performance comparison. The results show that compared to IED-IPC, in terms of energy cost, HAIED-IPC and HAIEPSD-IPC achieve 12.47 %/31.39 % reductions in first case and 15.16 %/24.89 % in second case. Additionally, HAIED-IPC and HAIEPSD-IPC achieve 12.35 %/24.71 % total anual cost (TAC) reduction and 16.67 %/33.39 % CO2 emissions reduction in first case while 10.53 %/14.20 % TAC reduction and 15.31 %/25.27 % CO2 emissions reduction in second case. In comparison with heat-integrated pressure-swing heterogeneous azeotropic distillation, HAIED-IPC and HAIEPSD-IPC also achieve 15.32 % and 18.87 %TAC reductions in second case, further underscoring the advantages of the proposed methods. These results highlight the significant benefits of integrating natural decanter and pressure swing configuration in the IED-IPC for the separation of ternary heterogeneous mixtures.