Feasibility exploration and performance assessment of extractive distillation processes for separation of different high concentration feed compositions based on multi-objective optimization

Abstract

The separation of azeotropic mixtures with high concentration composition has received increasing attention in recent years. This paper investigates the feasibility of different distillation processes to separate the ternary mixtures with a high concentration composition when the high-concentration composition is stable node or non-stable node. When the high concentration composition is stable node, the conventional three-column ED process (CTC), the four-column ED process with a preconcentration column (FCPC) and the three-column ED process with a combined distillation column (TCDC) can separate the mixtures. When the high concentration composition is non-stable node, only the CTC can separate the mixtures. Taking the NPA/THF/water system in which NPA and water are stable nodes, THF is non-stable node as an example, the results show that the TCDC process gets the best energy saving and cost reduction. Compared with the CTC processes of 0.8 water /0.1 NPA /0.1THF and 0.8 NPA /0.1 water /0.1THF systems, the TCDC processes reduce the energy consumption by 53.53 % /46.01%, the TAC by 57.49% /57.43%, the CO2 emissions by 60.12%/57.52% and the entropy generation 57.74%/45.31%.