Energy-efficient heterogeneous azeotropic distillation coupling with pressure swing distillation for the separation of IPA/DIPE/Water mixture

Abstract

Isopropyl alcohol/diisopropylether/water mixture is commonly produced in the IPA production process. Improvement of the separation of water-rich mixture is crucial to achieve green production of IPA. Conventional extractive distillation proposed in recent literature was reproduced by revised VLLE binary parameters to ensure the accuracy of simulation results. A newly proposed energy-efficient process is developed based on the idea of liquid-liquid separation coupling with pressure-swing distillation in this work. Thorough consideration in different distillation regions on the complex residue curve map and optimization of the process parameters using sequential iterative method lead to a simple configuration of separation process without needing of foreign component as entrainer. Further heat-integrated strategies are analyzed and implemented in the proposed system to ensure the good energy-efficiency of the process. The final heat-integrated novel design flowsheet can save up to 33.0% in total operating cost and 23.0% in total annual cost as compared to extractive-distillation system proposed in recent literature, showing the potential of this energy-efficient configuration applied on mixture with the most complicated residue curve map.