Economic and Environmental Assessment of a Novel Integrated Three-Column Extractive Distillation Process for Recycling Organics from Wastewater

Abstract

For diluted wastewater with azeotropes discharged from chemical plants, it is important to design a sustainable extractive distillation process to achieve efficient separation. By separating the dilute wastewater containing isopropanol and acetonitrile, it is proved that the four-column extractive distillation processes with a preconcentration column and a novel threecolumn process containing an integrated column with preconcentration and solvent recovery function can achieve energy conservation and cost reduction. At the same time, heat integration and heat pump-assisted technologies were further used to intensify the proposed processes. The proposed processes are evaluated in terms of economy, energy consumption, and CO 2 emissions. The results display that the double heat pump-assisted extractive distillation process can obtain 75.10% energy saving and the heat integration of the extractive distillation process with a preheater can save 69.45% cost, compared with the conventional extractive distillation process.