(607c) New PSA Cycle for CO2 Removal during Closed-Loop Human Space Exploration Missions

Authors: 
Erden, H., University of South Carolina
Ebner, A. D., University of South Carolina
Ritter, J. A., University of South Carolina

The objective of this presentation is to provide modeling and/or experimental details about the development of a novel PSA cycle that can be used for enriching and recovering CO2 from a spacecraft cabin that is suitable for use in a Sabatier reactor. This novel PSA cycle will utilize a combination of equalization, cocurrent depressurization and heavy reflux cycle steps to facilitate heavy component enrichment and recovery. Preliminary results obtained with the group’s dynamic adsorption process simulator (DAPS) revealed that a novel PSA cycle design utilizing 13X zeolite is indeed capable of enriching a dry gas stream of N2 containing 3500 ppm of CO2 to over 95 vol% CO2 at high recovery with a similar removal rate to that of NASA’s current 5A zeolite system, which utilizes a temperature swing adsorption (TSA) cycle. Implications from these results potentially reach far beyond the needs of NASA and begin to hint at the extreme concentration of CO2 from ambient air at relatively high recovery or the extreme concentration of any dilute species from a light gas stream using a simple PSA cycle. This presentation will discuss the most recent results obtained from DAPS and/or a multi-bed PSA system currently being modified for this unique application. This presentation will also discuss the most recent DAPS results obtained with a packed bed of commercial beaded adsorbent and/or a bed filled with a corrugated structured adsorbent that will facilitate higher mass transfer kinetics and lower flow resistance, thereby allowing for higher flow rates with significant bed size reduction.