Subscale Testbed for Characterizing Regenerable Adsorbents used in Air Revitalization of Spacecraft Atmospheres

A sub-scale testbed for characterizing the dynamic performance of regenerable adsorbents for filtering trace contaminants (TCs) from cabin atmospheres was built and tested. Regenerable adsorbents employed in pressure-swing adsorption (PSA) systems operate in a dynamic environment, where they undergo repeated loading / regeneration cycles. Adsorbents have a given chemical specificity for non-methane TCs depending on their composition, and on the humidity and temperature at which they operate. However, their ability to filter TCs is also affected by contact time, cycle time, regeneration vacuum quality and thermal conditioning. The test stand supplies gases of known composition and humidity to an adsorbent bed during the loading half-cycle, and allows automated sampling of inlet (pre-bed) and outlet (post-bed) gas concentrations by a gas chromatograph (GC) and a CO₂ analyzer, The filter bed is designed for vacuum swing regeneration during short cycles (6 min) using high quality (<0.5 torr) vacuum. The test stand will be used to catalog the chemical specificity and dynamic performance of candidate adsorbents for future atmosphere revitalization (AR) technologies using environmental ranges (e.g. relative humidities, temperatures, and target TC loads) found in manned spacecraft.