Automated hybrid distillation sequence synthesis framework of mixed azeotropes and nonazeotropes

Distillation technology is a crucial, energy-intensive component of energy-supply systems, thereby motivating the improved design of distillation systems. This study investigated an automated framework for synthesizing hybrid distillation sequences, providing a systematic approach for the design and optimization of distillation sequences involving azeotropes. The proposed method separated mixed azeotropes and nonazeotropes by replacing the simple columns in the superstructure of a conventional distillation sequence with extractive distillation columns. The automated calculation of the superstructures was implemented by calling the external interface of the process simulator. The results of these calculations were used to formulate a mixed-integer linear programming problem that was optimized with the objective function of the total annualized cost (TAC). Finally, the optimal solution and all feasible alternatives were obtained. Moreover, the reliability and efficiency of the proposed framework were demonstrated through two case studies. The results show that the separation position of the azeotrope in the sequence and the presence or absence of heat integration significantly impact the TAC of the system. However, using an existing component versus an external component as an entrainer makes very little difference in the TAC for the optimal sequences.