Thermodynamic Intrinsic Insights and Process Design for High-Efficiency Separation of Quaternary System with Three Azeotropes and Three Homologues

Pyridine compounds play a vital role in the field of biology and medicine as organic solvents, reagents, and precursors. The existing research focuses on separating binary systems consisting of water and single pyridine homologue. However, industrial pyridine wastewater combines with multiple azeotropes and homologues. As such, a novel approach for the simultaneous recovery of various pyridine homologues is developed based on heterogeneous azeotropic distillation (HAD). By investigating the coexistence of the complex azeotropic-homologue system, a suitable separation configuration is proposed. Through a systematic analysis of the intrinsic thermodynamic principles, it becomes feasible to achieve extremely high product purity directly after phase separation, thereby reducing the requirement of a distillation column. Additionally, an indirect shared condenser and decenter for the two-column method is proposed to further minimize energy consumption. The findings indicate that the triple-column heterogeneous azeotropic distillation sharing a decanter and condenser (TCHAD-SDC) process demonstrates superior separation capabilities after global optimization. Furthermore, this approach offers innovative concepts and solutions for the effective separation of complex industrial systems involving multiple azeotropes and homologues.