Monolithic Sorbents for Carbon Dioxide Removal 2006-01-2193

The NASA objective of expanding the human experience into the far reaches of space will require the development of regenerable life support systems. On-board carbon dioxide (CO₂) removal units play a key role in such systems ensuring high quality cabin air for crew members. Similar but more compact units are needed for extravehicular activities (space suit). The use of monolithic (e.g., honeycomb-shaped) rather than granular sorbents has the potential to result in a CO₂-removal system that possesses substantial weight, size, and power-requirement advantages over current systems (improved CO₂ adsorption and lower pressure drop). The subject of this study was the use and manufacture of lightweight, porous carbon monoliths with controlled pore characteristics that will serve as support for the sorbent material (e.g., liquid amines). The objective was to demonstrate the technical feasibility of the above approach. Several high surface area, high pore volume carbon monoliths were produced, and the pressure-drop advantage of monolithic sorbents over granular material was demonstrated. Thermal conductivity of monolithic carbon was measured and found to be significantly higher than the currently used polymer-based amine support. Preliminary testing of sorbent performance with respect to CO₂ adsorption capacity was performed and promising results were obtained.