• Coupled SOFC-SOEC system
• Oxygen
• SOEC
• SOFC

The decarbonization of energy-intensive industrial sectors remains a significant challenge due to their reliance on fossil fuels for high-temperature process heat. In industries with inherent process-related CO2 emissions, Carbon Capture, Utilization, and Storage technologies are essential. Among these, oxyfuel combustion enhances CO2 capture efficiency, though its implementation is currently limited by the high cost of oxygen. A promising solution involves an integrated system that couples a Solid Oxide Electrolysis Cell (SOEC) with a Solid Oxide Fuel Cell (SOFC) to produce high-purity oxygen.
This study investigates such a system with the primary objective of identifying the plant configuration that most efficiently meets a specified oxygen production target from an exergetic perspective. A thermodynamic model was developed using Ebsilon Professional and emplyed to perform a sensitivity analysis. Assuming negligible pressure losses, results indicate that efficient oxygen production is achieved with high water-hydrogen recirculation rates (corresponding to low utilization factors in the electrochemical components) and low current densities. However, when pressure losses are taken into account, operating at higher current densities (thus reducing the active surface area of the SOEC and SOFC) becomes advantageous, improving both efficiency and overall system feasibility.