Carbon Dioxide Deposition for Removal of Volatile Organic Compounds (CDep VOC)

Atmospheric management for space missions requires an integrated workflow of carbon dioxide (CO2) removal and conversion. The CO2 removal system can trap and concentrate specific volatile organic compounds (VOCs) in spacecraft cabin air along with carbon dioxide. These VOC contaminants, namely carbon disulfide, carbonyl sulfide, and octafluoropropane, can be detrimental when using catalytic packed beds for oxygen recovery, affecting performance and lifetime. Therefore, a VOC mitigation system between the CO2 removal and CO2 conversion system is required to purify the CO2. Cold surface generation via cryocoolers can separate CO2 from VOCs due to the deposition and sublimation temperature differences between the species. NASA Ames Research Center has been developing CO2 cold surface deposition (CDep) technology for CO2 capture from air. This technology was adapted into a new test system for VOC mitigation to remove contaminants from captured CO2, dubbed CDep VOC. Design of the full-scale benchtop test has been completed, and the build is in progress, with the goal to achieve successful separation of trace VOCs from CO2 as well as passive pressurization for immediate use in an oxygen recovery system.