Process design and optimization of the reactive-extractive distillation process assisted with reaction heat recovery via side vapor recompression for the separation of water-containing ternary azeotropic mixture

Abstract

To facilitate the high-energy-consumption separation of water-containing azeotropes, a reactive-extractive coupled distillation (RED) method has been proven as an effective approach. However, the reaction heat has not been fully utilized and the entrainer recovery column can be further improved in thermodynamics. For these purposes, different intensified methods have been developed in this study. Firstly, two published RED processes are conducted in IPA/DIPE/water system. To improve thermodynamic performance, a flash-coupled double-column reactive-extractive distillation (FL-DCRED) process is developed. These three processes are optimized to minimize total annual cost (TAC) via the particle swarm optimization algorithm. To fully utilize the reaction heat, a side-vapor-recompression and heat-integrated DCRED (SVRHI-DCRED) process is further designed by analyzing the temperature-enthalpy (T-H) diagram. Various evaluation methods are employed to assess the economic, environmental, thermodynamic effects, and energy recoverability of each process. The SVRHI-DCRED process is the most superior process across all indexes, which are 29.5%, 56.5%, 206.3% lower with respect to the DCRED process regarding TAC, CO2 emission, and maximum energy recoverability index, respectively. The thermodynamic efficiency is elevated from 38.27% to 43.10% via exergy analysis. The SVRHI configuration could be applicable to other processes with highly exothermic reaction for obtaining a more energy-efficient and economically advantageous process.