Energy-efficient heterogeneous triple-column azeotropic distillation process for recovery of ethyl acetate and methanol from wastewater
Ao Yang, Shirui Sun, Zong Yang Kong, Shuangshuang Zhu, Jaka Sunarso, Weifeng Shen
Abstract
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.