Design of a Stand-alone Solid Oxide Electrolysis Stack with Embedded Sabatier Reactors for 100% Oxygen Regeneration

Solid oxide electrolysis with embedded Sabatier reactors is being developed to regenerate all the oxygen required by a crew, eliminating any resupply needs. Metabolically produced carbon dioxide and water are electrolyzed at high temperature to produce pure dry oxygen. Carbon monoxide and hydrogen byproducts are converted to methane and water in the embedded Sabatier reactor. As it is embedded in the electrolyzer, the water is further electrolyzed to produce additional oxygen. A demonstration unit has been designed at full scale with a design production rate equivalent to that required to support one third of one person's oxygen requirements. Stack design was configured to enable the electrolyzer and Sabatier stacks to operate at their respective temperatures. Thermal modeling was performed to support internal heater sizing, insulation design, and evaluate touch temperatures. The unit was built and tested. Modeling and initial testing results are presented.