Novel approach to integrate CO2 utilization coupled with direct methane conversion to C2 products using solid oxide electrolysis cell

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Vol. 444; p. 136619
• Main Authors: Kyun Kim, Seong, Kwon, Young-il, Beom Kim, Yeong, Jung, Jongyun, Kang, Sanggyu, Hoon Joo, Jong
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15-09-2022
• Subjects: CO2 reduction; Oxidative coupling of methane; Process intensification; Thermal management; ASU; OCV; GHSV; C2H4 and C2H6; CO2; GDC; DRT; Process intensification; Oxidative coupling of methane; MFC; LSGM; EIS; SOECs; MNW; OCM; STFC; Thermal management; SEM; CO2 reduction; MIEC; WIP
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2022.136619

•Efficient integration of CO2 electrolysis and OCM in single reactor was proposed.•Heat demand of SOEC can be compensated from waste heat of OCM process.•C2 yield of 25.4% at 825 ℃ coupled with CO2 electrolysis at 850 ℃ was achieved, simultaneously.
Solid oxide electrolysis cells (SOECs) based on oxygen ion-conducting electrolytes driven at high temperatures have been considered promising candidates for CO2 utilization and energy storage to mitigate environmental problems because of their high current density and efficiency. Additionally, SOECs have potential to integrate with processes that require high-temperature pure oxygen produced at anode and CO2 utilization at cathode. Despite this advantage, CO2 utilization via SOEC has been extensively studied only for the practical use and development of CO2 electrolysis electrodes. In this study, we propose novel strategy that synergistically integrates both CO2 electrolysis and OCM in single apparatus. A previous study on OCM using SOEC resulted in low C2 yield, highlighting the difficulty to develop anode electrode that satisfies the MIEC property to promote the oxygen evolution reaction as well as the catalytic activity to improve CH4 conversion and C2 selectivity. Herein, CO2 electrolysis coupled with the OCM reaction (C2 yield of 25.4% at 825 °C) was achieved through reactor capable of independently controlling operating conditions of two reactions in one apparatus. Furthermore, thermodynamic simulation analysis demonstrated that the conversion efficiency of the proposed OCM-SOEC system is superior to that of the conventional OCM-air separation unit (ASU) system.