Quantification of Methane Generation using a Solid Oxide Electrolyzer with an Electrode-based Sabatier Reactor for Oxygen Regeneration

Solid Oxide Electrolysis with an embedded Sabatier reactor is being developed for regenerative air revitalization. In a previous effort, an embedded Sabatier reactor was demonstrated using a nickel-based electrode in a SOE cell. To explore the performance potential, new experiments were performed at various operating temperatures and inlet gas compositions. Successful methane and oxygen regeneration was achieved. The gas compositions fed to the cell were a mixture of carbon dioxide, water, carbon monoxide, and hydrogen in ratios indicative of a previously electrolyzed stream of metabolically produced by-products (carbon dioxide and water vapor) of nominal crew activity. The composition was varied by simulating various degrees of oxygen regeneration by upstream electrolysis cells. All results are presented and compared to previous testing where applicable. Carbon deposition was observed in the inlet tube to the cell. Theory is presented that confirm carbon deposition did not occur inside the test cell.