Feasibility Demonstration of a Solid Oxide Electrolyzer with an Embedded Sabatier Reactor for Oxygen Regeneration

Solid Oxide Electrolysis (SOE) with an embedded Sabatier reactor is an innovative and efficient concept for regenerative air revitalization. The concept safely eliminates handling of hydrogen, and works regardless of gravity and pressure environments with no moving parts and no multi-phase flows. It also is efficient because it requires no expendables from Earth while being compact with minimal impact on mass. The consequence is significant because SOE is an inherently suitable technology (and possibly the only technology) for enabling 100% oxygen regeneration from carbon dioxide and water vapor, two byproducts of crew activity that must be managed. To investigate the feasibility of this concept, a Sabatier reactor was successfully embedded into a single SOE cell. Experiments were conducted by inputting into the cell a mixture of CO₂, water vapor, CO and hydrogen in ratios indicative of a pre-electrolyzed stream of metabolically produced byproducts (CO₂ and H₂ O) of nominal crew activity. The cell successfully produced methane in both Sabatier and electrolysis modes. Further, results suggest that, depending upon flow rate, methane production can be increased if simultaneous electrolysis is performed in the embedded Sabatier reactor. Finally, results suggest that the electrolysis performance of the embedded Sabatier reactor achieves the same magnitude of common SOE cells.