Improved process design and optimization of 200 kt/a ethylene glycol production using coal-based syngas

Abstract

Ethylene glycol (EG) production via coal-based syngas has been demonstrated to be an attractive process with a higher conversion and lower energy consumption. However, few researches are focused on the improved design of the reactors and separation strategies that involved in the syngas-to-EG process (STEP). In this work, the improved design and optimization of key techniques in 200kt/a EG production using syngas are investigated. We propose a new four-stage fixed bed tube-type CO coupling reactor (CCR) and the reaction temperature and product DMO distribution along the pipe are suggested. Then, the recovery of renewable methanol is carried out by the application of three-stage membrane separation configuration (TSMSC) instead of conventional two-column distillation. Furthermore, conventional double columns distillation is replaced by dividing-wall columns (DWCs) in the separation of mixtures DMO-DMC-methanol. The comparisons of energy consumption and total annualized cost (TAC) between the proposed technologies and conventional processes verify the superiority of the implement of TSMSC and DWCs. Eventually, the optimization of key operational parameters of the STEP is achieved with a higher EG yield and a lower energy consumption, which demonstrates that the proposed STEP flowsheet could provide a more effective and economical solution to EG production. The methodology proposed in this work may provide some theoretical guidance to the improved design of reactors and separations alternatives in chemical production processes.