Conceptual design of sustainable extractive distillation processes combining preconcentration and extractive distillation functions for separating ternary multi-azeotropic mixture

Azeotropic mixtures with a large content of one component are often encountered. Several energy -efficient three-column extractive distillation processes with integrated distillation column (TCED-IDC) are conceptually designed for separating ternary multi-azeotropic mixtures with a large content of one component on the basis of the corresponding four-column extractive distillation (FCED) processes. The energy consumption and economic advantages of the TCED-IDC processes which realize the integration of extractive distillation function and preconcentration function are demonstrated by two cases, metha-nol/acetonitrile/benzene ternary azeotrope with chlorobenzene as solvent (Case1) and methyl acetate/ ethyl acetate/methanol ternary azeotrope with dimethyl sulfoxide as solvent (Case2). The economic sav-ings resulting from the integration of preconcentration function and extractive distillation function depend heavily on feed compositions and azeotropic compositions. In terms of assumed feed composi-tions, the TCED-IDC process can achieve 27.61%/21.64% economic costs reduction in Case1 and 49.66%/1.73% economic costs reduction in Case2 compared to the TCED process and the FCED process. (c) 2022 Elsevier Ltd. All rights reserved.

Automated summary

In this study, an efficient three-column extractive distillation process (TCED-IDC) was designed for separating ternary multi-azeotropic mixtures with a large content of one component. The energy and economic advantages of the TCED-IDC processes were demonstrated through two case studies.