Process Development and Technoeconomic Analysis of Different Integration Methods of Coal-to-Ethylene Glycol Process and Solid Oxide Electrolysis Cells
Qing Yang, Qing Yang, Genyun Chu, Qingchun Yang, Qingchun Yang, Jinliang Zhang, Huairong Zhou, Dawei Zhang
Abstract
The conventional coal-to-ethylene glycol (CtEG) process is criticized for its high CO2 emissions. Because most CtEG projects are located in areas rich in renewable energy such as wind energy and solar energy, two novel green hydrogen-assisted CtEG processes are proposed and analyzed by the integration of solid oxide electrolysis cell (SOEC) technology: the CtEG process integrated with the SOEC technology of only steam electrolysis (SOEC-CtEG) and that of steam and carbon dioxide electrolysis (CoSOEC-CtEG). The effects of the operating temperature, current density, and inlet gas composition on the electrochemical performance of the solid oxide steam electrolytic and coelectrolytic processes are investigated and compared based on their electrochemical and flowsheet-based models. The thermodynamic and technoeconomic advantages of the two proposed processes are manifested by comparison with a conventional process. The results show that the two proposed processes are promising because they increase the carbon utilization efficiency by 26.13 and 22.48%, increase the exergy efficiency by 14.82 and 17.34%, decrease the total capital investment by 23.60 and 19.38%, decrease the levelized production cost by 20.55 and 27.47%, and increase the internal rate of return by 8.85 and 9.18%. In addition, the sensitivity analysis results show that the two proposed processes have stronger antirisk ability than the conventional process.