Carbon dioxide (CO2) removal from crewed spacecraft atmospheres is critical to maintaining crew health and performance. In the past, non-regenerable technologies, such as lithium hydroxide (LiOH) canisters have been used. Such technologies may not be feasible for long-duration missions due to the mass and volume requirements associated with long-term use. Regenerable technologies for CO2 removal are currently in use on the ISS (4 Bed CO2 Removal (4BCO2), Carbon Dioxide Removal Assembly (CDRA) and Vozdukh). However, these current methods of CO2 removal that utilize adsorbent beds are inefficient at lower partial pressures of CO2, only perform in batch operations, may require frequent maintenance, and may experience degradation over constant use. Therefore, it is necessary to explore new technologies that increase reliability and performance, as well as reducing the mass and power required for CO2 removal. Ionic liquid-based CO2 removal systems are a promising solution to these challenges. Specifically, a scrubber-stripper setup enables a continuous loop of ionic liquid to remove and recover CO2 from a cabin atmosphere. This work presents a system-level V-HAB model of a of an ionic liquid scrubber-stripper setup, which implements a novel component-level hollow fiber gas-liquid contactor model that can be utilized for both CO2 absorption into and desorption from the ionic liquid. This model underwent validation via comparison to empirical data in a trio of cases: isolated gas-liquid contactor in the scrubbing orientation, lab scale scrubber-stripper, and planned full scale scrubber-stripper. Through the implementation and future development of these models, ionic liquid-based CO2 removal systems can be assessed for use in crewed habitats.
Singh et al. (2024) studied this question.