Increased Oxygen Recovery Using Plasma Pyrolysis Technology and Electrochemical Hydrogen Separation

Currently on the International Space Station, approximately 50% of the oxygen (O2) for the crew is recovered from metabolic carbon dioxide (CO2). Maximum O2 recovery is required to reduce resupply mass for long-duration manned missions. O2 recovery is constrained by the limited availability of reactant hydrogen (H2) from water (H2O) electrolysis, and Sabatier-produced methane (CH4) is vented as a waste product resulting in a continuous loss of reactant H2. The Plasma Pyrolysis Assembly (PPA) has the potential to substantially increase O2recovery by post-processing the Sabatier-produced methane to recover H2. The PPA decomposes CH4 into predominately H¬2 and acetylene (C2H2). A separation system is needed to purify the H¬2 from the PPA stream before it is recycled back to the Sabatier reactor. Two sub-scale electrochemical H2 separation systems, developed by Skyre, Incorporated, were delivered to NASA for evaluation. This report details the results of Phase I testing and evaluation of the C2H2 removal systems.