Energy-efficient heterogeneous triple-column azeotropic distillation process for recovery of ethyl acetate and methanol from wastewater

The challenging separation of ethyl acetate (EtAC) and methanol (MeOH) from wastewater involves two azeotropes and a distillation boundary. Although extractive distillation (ED) has been explored, the heterogeneous region within the ternary azeotropic mixture has been overlooked, which suggests the possibility of using a decanter to cross the distillation boundary when the feed composition is present in the heterogeneous region. This study introduces a novel heterogeneous triple-column distillation (NHTCD) that eliminates the external solvent injection, simplifying the complex ED processes. The NHTCD process is developed via a systematic approach, comprising conceptual design based on thermodynamic insights and process optimization to determine the optimum configuration. Furthermore, heat integration (HI) and heat pump-vapor recompression (HP-VR) techniques were explored for energy conservation. Evaluation of energy, economic, and environmental (3E) aspects shows that the hybrid HP-VR with HI NHTCD process outperforms ED, achieving 87 %, 57 %, and 86 % reductions in energy, economic, and environmental emissions, respectively.