Hydrogen Purification in Support of Plasma Pyrolysis of Sabatier Derived Methane

The use of microwave regenerative sorption media for purification of hydrogen has been studied. The Sabatier Assembly recovers oxygen from carbon dioxide while consuming hydrogen and producing methane and water. The Plasma Pyrolysis Assembly (PPA) is being developed to recover most of the hydrogen from the methane. Acetylene and smaller amounts of other hydrocarbons are produced as byproducts of PPA operation. The present project is directed toward purifying the hydrogen product gas using sorption media and subsequently thermally regenerating the media using microwave power. The penetrative nature of microwave heating is utilized to efficiently drive gas desorption from the physical sorbents. Microwave heating drives off captured contaminants from a sorbent bed (which is held at relative vacuum) during regeneration. A series of molecular sieves, activated carbons and high surface area forms of alumina and silica were evaluated as candidate sorbent materials. Additionally, water vapor removal with the use of silica gel was evaluated. As a result of this research, hydrogen recovery from Sabatier methane is improved, thereby further closing the air-loop. Such increases in efficiency are necessary for crewed deep space exploration missions.