Advanced Supported Liquid Membranes for Carbon Dioxide Control in Cabin Applications

Date

2016-07-10

Journal Title

Journal ISSN

Volume Title

Publisher

46th International Conference on Environmental Systems

Abstract

The development of new, robust, life support systems is critical to NASA’s continued progress in space exploration. One vital function is maintaining the carbon dioxide (CO2) concentration in the cabin at levels that do not impair the health or performance of the crew. The CO2 removal assembly (CDRA) is the current CO2 control technology on-board the International Space Station (ISS). Although the CDRA has met the ISS needs to date, the repeated cycling of the molecular sieve sorbent causes it to break down into small particles that clog filters or generate dust in the cabin. This reduces reliability and increases maintenance requirements.

Another approach that has potential advantages over the current system is a membrane that separates CO2 from air. In this approach, cabin air contacts one side of the membrane while other side of the membrane is maintained at low pressure to create a driving force for CO2 transport across the membrane. In this application, the primary power requirement is for the pump that creates the low pressure and then pumps the CO2 to the oxygen recovery system.

For a membrane to be practical, it must have high CO2 permeation rate and excellent selectivity for CO2 over air. Unfortunately, conventional gas separation membranes do not have adequate CO2 permeability and selectivity to meet the needs of this application. However, the required performance could be obtained with a supported liquid membrane (SLM), which consists of a microporous material filled with a liquid that selectively reacts with CO2 over air. In a recently completed Phase II SBIR project, Reaction Systems, Inc. fabricated an SLM that is close to meeting permeability and selectivity objectives for use in the advanced space suit portable life support system. This paper describes work carried out to evaluate its potential for use in spacecraft cabin application.

Description

United States
Reaction Systems, Inc.
NASA
302
ICES302: Physio-chemical Life Support- Air Revitalization Systems -Technology and Process Development
Vienna, Austria
David T. Wickham, Reaction Systems, Inc., USA
Jeffrey R. Engel, Reaction Systems, Inc., USA
The 46th International Conference on Environmental Systems was held in Vienna, Austria, USA on 10 July 2016 through 14 July 2016.
Kevin J. Gleason, Reaction Systems, Inc., USA
Cinda Chullen, NASA Johnson Space Center, USA

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Keywords

carbon dioxide (CO2), CO2 removal assembly (CDRA), CO2 control technology, International Space Station (ISS), molecular sieve sorbent, low pressure, CO2 transport, CO2 permeation, membranes, CO2 selectivity, Reaction Systems, supported liquid membrane (SLM)

Citation