An Advanced CO2 Removal System using Regenerable Solid Amines

The collection and concentration of CO2 using thermally regenerated solid amine systems has been previously demonstrated in NASA development programs over the last 30 years. Most recently UTAS is developing a NAVY CO2 removal system using thermally regenerated amines for a crew of approximately 125 persons. Our Advanced CO2 Removal System incorporates lessons learned from over 35 years of experience with solid amines, coupled with recent high TRL design features.

Our approach incorporates a passive means of water vapor recover, using desiccant materials in thermally linked sorbent beds, upstream of the solid amine sorbent beds, to affect an approximate 90% nominal water (humidity) recovery with minimal power. The residual water vapor and CO2 are subsequently removed by SA9T amine sorbent in a second set of sorbent beds. The dry, CO2 free effluent is then used to regenerate the desiccant beds using a simple sweep gas desorption.

When the amine beds are loaded with CO2 to their design capacity, they are heated to approximately 60 degrees C, while simultaneously drawing a vacuum to desorb the CO2 and residual water vapor. The residual water vapor is removed from the CO2 product stream via sorbent beds, or a condensing heat exchanger, depending on the subsequent downstream processing requirements of the CO2. The concentrated CO2 can then be dumped overboard or sent to a CO2 reduction system such as Sabatier.

A significant advantage to utilizing solid amines is that they are relatively insensitive to incoming water vapor and therefore large desiccant beds are not required upstream of the CO2 sorbent beds. Additionally, the passive nature of the water recovery and moderate regeneration temperature of the amine, result in reduced power requirements compared to the state of the art CO2 removal systems.

This paper presents the current development status of a TRL4 system.