Electrolyte Membrane Hydrogen Recovery for Advanced Oxygen Recovery Architecture

NASA’s endeavor to further enable long duration manned space exploration requires further closure of the oxygen loop of the life support system than is currently realized aboard the International Space Station. Currently, oxygen is recovered from crew generated carbon dioxide via the use of a Sabatier carbon dioxide reduction system coupled with water electrolysis. Water is electrolyzed to form oxygen for crew consumption as well as hydrogen. The hydrogen is reacted with carbon dioxide forming water and waste methane gas. Since hydrogen is lost from the desired closed loop system in the form of methane, there is insufficient hydrogen available to fully react all of the carbon dioxide, resulting in a net loss of oxygen from the loop. In order to further close the oxygen loop, NASA has been developing an advanced Plasma Pyrolysis technology that further converts the waste methane to higher order hydrocarbons in order to better utilize the hydrogen for oxygen recovery. This Plasma Pyrolysis produces a product gas stream that consists of hydrogen, hydrocarbons, and a significant concentration of carbon monoxide. In order for this Plasma Pyrolysis technology to be feasible, there must be a means to separate the hydrogen from the other compounds for recycle to the Sabatier reactor. Sustainable Innovations’ signature electrochemical cell architecture provides a solution to NASA’s search for regenerative separation technology enabling maximum hydrogen recovery from a stream containing water vapor, carbon monoxide (CO), and hydrocarbons including methane, acetylene, ethane, and ethylene, among others. Separation of hydrogen from mixed gaseous streams presents a significant technical challenge for various NASA applications in addition to posing a significant opportunity for commercial uses. Sustainable Innovations is developing a technology that extracts hydrogen from a mixed stream by electro-oxidization of the hydrogen and subsequent electro-reduction of the resultant protons in a separate chamber. The process, when combined with an electrochemical cell architecture that is engineered to tolerate high differential pressure, can be used to separate and compress hydrogen in a single step. The process is proven to be efficient, quiet, and highly reliable. It requires no reciprocating compressor, so it is largely maintenance free.