Sabatier Reactor System Integration with Microwave Plasma Methane Pyrolysis Post-Processor for Closed-Loop Hydrogen Recovery

Abstract

The Carbon Dioxide Reduction Assembly (CRA) designed and developed for the International Space Station (ISS) represents the state-of-the-art in carbon dioxide reduction (CDRe) technology. The CRA produces water and methane by reducing carbon dioxide with hydrogen via the Sabatier reaction. The water is recycled to the Oxygen Generation Assembly (OGA) and the methane is vented overboard resulting in a net loss of hydrogen. The proximity to earth and the relative ease of logistics resupply from earth allow for a semi-closed system on ISS. However, long-term manned space flight beyond low earth orbit (LEO) dictates a more thoroughly closed-loop system involving significantly higher recovery of hydrogen, and subsequent recovery of oxygen, to minimize costs associated with logistics resupply beyond LEO. The open-loop ISS system for CDRe can be made closed-loop for follow-on missions by further processing methane to recover hydrogen. For this purpose, a process technology has been developed that employs a microwave-generated plasma to reduce methane to hydrogen and acetylene resulting in 75% theoretical recovery of hydrogen. In 2009, a 1-man equivalent Plasma Pyrolysis Assembly (PPA) was delivered to the National Aeronautics and Space Administration (NASA) for technical evaluation. The PPA has been integrated with a Sabatier Development Unit (SDU). The integrated process configuration incorporates a sorbent bed to eliminate residual carbon dioxide and water vapor in the Sabatier methane product stream before it enters the PPA. This paper provides detailed information on the stand-alone and integrated performance of both the PPA and SDU. Additionally, the integrated test stand design and anticipated future work are discussed.

Integrated Atmosphere Resource Recovery and Environmental Monitoring Technology Demonstration for Deep Space Exploration

“…While the degree of closure is not complete in that a CH 4 product is produced, this product may be either used by other systems, propulsion for instance, or further processed to recover more hydrogen (H 2 ) via a plasma pyrolysis process. 13 Work to advance the Bosch process to viability may provide the highest degree of resource recovery if dicated by future exploration mission objectives.…”

Evaluation of Sorbents for Acetylene Separation in Atmosphere Revitalization Loop Closure

“…CH 4 = Methane CM = Crew Member CO 2 = Carbon Dioxide CRA = Carbon Dioxide Reduction Assembly MSFC = Marshall Space Flight Center OGA = Oxygen Generation Assembly PCI = Precision Combustion, Inc. PPA = Plasma Pyrolysis Assembly QMS = Quadrapole Mass Spectrometer VVS = Venturi Vacuum System µGC = Micro-Gas Chromatograph…”

“…2 During this testing, the PPA was integrated with a CRA development unit and showed promising results. If used in flight, the PPA has the potential to increase oxygen recovery by more than 300 lbm per crew member (CM) per year, beyond CRA alone.…”

Series Bosch System Development

“…Testing of development-level hardware for the SOA system suggests that only about 42% O 2 recovery is actually achieved. 1 This results in a loss of over 153 kg O 2 per crew member (CM) per year. For a crew of four, and assuming $55,000 to launch one kilogram of mass to ISS ($25,000 per pound), this translates to annual launch costs of over $37.8M, when resupplied as water.…”