Marshall Space Flight Center, Alabama
A novel, short-contact-time Microlith Sabatier reactor system for CO2 reduction offers a significant advance in support of manned spaceflight. Compared to the current and prospective alternatives (including microchannels), the reactor is much smaller and lighter, more energy and resource efficient, and more durable. In the spacecraft cabin atmosphere revitalization system (ARS), the utilization of CO2 to produce life support consumables such as O2 and H2O, via the Sabatier process as part of the CO2 Reduction Assembly (CRA), is an important function.
This innovation is an integrated, stand-alone system consisting of a Microlith-based CO2 methanation reactor, water separation and recovery system, and automatic control software for ground demonstration. The system efficiently achieves high CO2 conversion and high CH4 selectivity for optimum water generation. The apparatus is capable of operating at high throughput while maintaining targeted performance of close-to-equilibrium CO2 conversion. The specific mass and volume of the reactor are much lower compared to the state-of-the-art metrics.
H2 and CO2 (reactants) enter the system, and their flow rates are automatically controlled. The catalyst within the reactor promotes the conversion of the reactants to H2O and CH4. Since the reaction is exothermic, a thermal management approach is implemented to maintain reactor operating temperature and to avoid catalyst deactivation. The product H2O is separated from the CH4 via a condenser and separator system to provide two single-phase product streams.
This innovation utilizes a novel thermal management approach to enable self-sustained operation without additional power requirements. A full support system including mass flow controllers, valves, heat exchanger, and water condensation and separation system was developed. The reactor and system were integrated with a newly developed automatic control system that enables single pushbutton start and steady-state operation with minimal user interface.