Analysis of Performance Degradation of Silica Gels after Extended use Onboard the ISS



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48th International Conference on Environmental Systems


The disassembly of two flight desiccant beds from the Carbon Dioxide Removal Assembly (CDRA) revealed significant discoloration of the silica gel near the bed inlet as well as a coincidental performance loss. This material was analyzed for the presence of chemical contaminants, physical porosity changes, and adsorption performance. The material characteristics are compared against the location in the bed from which they were sampled in order to develop profiles through the bed. Additional testing of the beds prior to disassembly provided more data points. Possible mechanisms for the loss of capacity are provided though no root cause has been confirmed. Extrapolation of the performance loss is used to estimate the required oversizing of the silica gel layer for long-term operation.


Gregory Cmarik, Jacobs ESSSA, NASA/MSFC/ES62
James Knox, NASA/MSFC/ES62
Timothy Huff, NASA/MSFC/EM22
ICES302: Physio-chemical Life Support- Air Revitalization Systems -Technology and Process Development
The 48th International Conference on Environmental Systems was held in Albuquerque, New Mexico, USA on 08 July 2018 through 12 July 2018.


Carbon Dioxide Removal Assembly, CDRA, 4 bed molecular sieve, 4BMS, silica gel, desiccant, contamination