Sustainable separation of ternary azeotropic mixtures based on enhanced extractive distillation/pervaporation structure and multi-objective optimization

Abstract

The development of an efficient separation and purification process for ternary aqueous azeotropes is very important to balance their economic and environmental benefits. Based on the high efficiency of extractive distillation in azeotrope separation and the low consumption of pervaporation technology, it is essential to study the feasibility of the coupling process and its advantages when compared with the single distillation process. Considering a tetrahydrofuran/toluene/water azeotropic system, suitable extractants for the process of extracting and rectifying azeotropes were selected by analyzing the phase equilibrium and intermolecular interaction bonding mechanism. Implementing the non-dominated sorting genetic algorithm with economic cost and gas emissions (CO2, SO2 and NOx) as the multi-objective for process optimization, the optimal parameters and process scheme of extractive distillation and coupling process were obtained. In addition, different azeotrope feed compositions were analyzed to further judge the separation effect of the coupling process. Based on the multi-objective optimization algorithm, it was found that the coupled process was better than the single extractive distillation process economically and environmentally, which has significance for the separation of ternary aqueous azeotropes.