Conceptual design, optimization, and carbon emission analysis for the acrylonitrile/acetonitrile/water separation processes

Abstract

In this work, we firstly report on the rigorous design, optimization, and carbon emission analysis of the processes separating acrylonitrile (AN), acetonitrile (AC), and water. Two bi-sectional processes, which integrate heterogeneous extractive distillation with hybrid extraction-distillation (the HHED process), and that with pressure swing distillation (the HPSD process), are proposed. Compared with the existing configuration, operation using 30% less entrainer amount is found feasible for both processes, leading to 9.8% energy saving. Also, the optimized HHED process saves 4.8% total annual cost (TAC) and 5.8% carbon emission from the optimized HPSD process. Besides, implementing a vapor recompression cycle on the optimized HHED process reduces 31.1% CO2 emission but increases 6.6% of TAC. On the other hand, the heat-integrated HPSD process with an economizer design does not outperform the non-integrated HHED process. Finally, separation using heterogeneous azeotropic distillation or hybrid extraction-distillation process in single is conceptually rejected. Through this work, the industrial guidance could be provided.