Electrical-driven self-heat recuperative pressure-swing azeotropic distillation to minimize process cost and CO2 emission: Process electrification and simultaneous optimization

Abstract

Azeotropic separation by pressure-swing distillation (PSD) is one of the most costly processes in the chemical industry. To minimize process cost and CO2 emission, process electrification based on self-heat recuperation technology (SHRT) has been implemented in many thermal-driven processes. Enlightened by these facts, a novel electrical-driven PSD-SHRT process is proposed and compared with conventional thermal-driven PSD (PSD-CONV) and PSDs integrated with heat integration and heat pump. Two typical binary systems – tetrahydrofuran (THF)/water with minimum-boiling azeotrope and acetone/chloroform with maximum-boiling azeotrope – are selected to investigate the potential economic and environmental benefits of process electrification. To make a fair comparison, all the processes are optimized to a minimum in total annualized cost (TAC) based on a simulation-based optimization framework combining Aspen Plus (process simulator) and MATLAB (external optimizer). The optimization results indicate PSD-SHRT to be the lowest in both TAC and CO2 emission of all the alternative processes. In THF/water system, PSD-SHRT triumphs over PSD-CONV by 23.72% in TAC and 83.67% in CO2 emission, respectively. Corresponding values increase to 47.82% and 92.90% in the acetone/chloroform system. These improvements verify the significant advantages of process electrification and also encourage more originations to introduce SHRT into other processes.