Oxygen recovery will be a key element of advanced Environmental Control and Life Support Systems (ECLSS) on future deep space missions. The Plasma Pyrolysis Assembly (PPA) works in conjunction with a Sabatier Reactor, which is a leading oxygen recovery technology. The function of the PPA is to recover hydrogen from the Sabatier reactor products. The 3rd generation PPA processes the methane, produced by the Sabatier Reactor, at a 4 crew-member flow rate to produce hydrogen, acetylene, other trace gases and solid carbon fines. A Regenerable Carbon Filter (RCF) was developed under a SBIR by Umpqua Research Company to capture the nuisance carbon fines and was put through integrated ground testing with a 3rd generation PPA unit at the NASA Marshall Space Flight Center's ECLSS Environmental Chamber (E-Chamber). The filter system consists of three separate in-series components: a regenerable electrostatic precipitator, a regenerable fibrous media filter, and a passive HEPA filter. Oxidation is used to regenerate the two regenerable components by flowing a small amount of oxygen through the regenerable components at 750 C. The tests consisted of carbon loading from the PPA and regeneration stages. Two different duration carbon loading cycle were performed corresponded to a typical loading cycle of the PPA, 8 hours, before the PPA reactor requires regeneration, and a 20-hour loading cycle to test for performance under longer carbon build up. The effectiveness of regeneration was checked visually inside the electrostatic precipitator component through borescope inspection. In addition, the level of carbon oxidation during regeneration was monitored by measuring gaseous products with a gas chromatograph. The results of the two loading tests and multiple regeneration tests will be presented in this paper.
Berger et al. (Sun,) studied this question.