Regenerable Fine Carbon Particle Filter for Oxygen Recovery Systems

Oxygen in space is recovered through advanced oxygen recovery systems, which generate large amounts of carbon particles that must be removed for proper operation, integration into the habitat, and crew safety. There are multiple oxygen recovery technologies that may be used in the future (e.g., Plasma Pyrolysis Assembly [PPA], Bosch) that each suffer from unique carbon challenges. The PPA generates a small amount of extremely fine carbon (<0.3 µm) in a low-pressure hydrogen stream, while the Bosch process generates a large amount of carbon over a wide range (0.2 – 50 µm) in high-temperature steam. To meet these obstacles, Mainstream Engineering is developing and has demonstrated proof-of-concept operation of a multi-stage fine carbon particle filter. The filter uses an integrated cyclone separator to reduce particulate matter into a fixed collection chamber, followed by a combined inertial and electrostatic precipitator for general load reduction, and a final polishing filter for >99.9% collection efficiency. The system has been modeled through computation fluid dynamics (CFD), rapid prototyped, and validated at relevant carbon loadings and fluid streams, at sub-ambient pressures, and operation independent of gravity. Current work focuses on reducing size, weight, and power, fully validating operation under all conditions (e.g., start-up), evaluating final carbon collection, and speed of filter regeneration. This carbon filter system enables long-term operation and implementation of advanced oxygen recovery systems.