Microlith-based Structured Sorbent for Carbon Dioxide, Humidity, and Trace Contaminant Control in Manned Space Habitats

Abstract

To support continued manned space exploration, the development of atmosphere revitalization systems that are lightweight, compact, durable, and power efficient is a key challenge. The systems should be adaptable for use in a variety of habitats and should offer operational functionality to either expel removed constituents or capture them for closedloop recovery. As mission durations increase and exploration goals reach beyond low earth orbit, the need for regenerable adsorption processes for continuous removal of CO 2 and trace contaminants from cabin air becomes critical. Precision Combustion, Inc. (PCI) and NASA -Marshall (MSFC) have been developing an Engineered Structured Sorbents (ESS) approach based on PCI's patented Microlith ® technology to meet the requirements of future, extended human spaceflight explorations. This technology offers the inherent performance and safety attributes of zeolite and other sorbents with greater structural integrity, regenerability, and process control, thereby providing potential durability and efficiency improvements over current state-of-the-art systems. The major advantages of the ESS explored in this study are realized through the use of metal substrates to provide structural integrity (i.e., less partition of sorbents) and enhanced thermal control during the sorption process. The Microlith technology also offers a unique internal resistive heating capability that shows potential for short regeneration time and reduced power requirement compared to conventional systems. This paper presents the design, development, and performance results of the integrated adsorber modules for removing CO 2 , water vapor, and trace chemical contaminants. A related effort that utilizes the adsorber modules for sorption of toxic industrial chemicals is also discussed. Finally, the development of a 4-person two-leg ESS system for continuous CO 2 removal is also presented. Nomenclature

Ionic-Liquid-Based Contactors for Carbon Dioxide Removal from Simulated Spacecraft Cabin Atmospheres

“…Several regenerable sorbent materials have been researched for CO 2 removal from space habitat atmospheres, which include zeolite-coated Microlith mesh substrates [13], zeolite sorbent materials [3]- [6], [13]- [15], liquid and solid amines [16]- [17], and ionic liquids [18]. Implementations for treatment of spacecraft cabin or spacesuit atmospheres include the CO 2 Removal and Compression System (CRCS) [19], the CO 2 And Moisture Removal Amine Swing-bed (CAMRAS) [16], the Rapid Cycling Amine (RCA) system [17], Supported Ionic Liquid Membranes (SILMs) [20]- [23], and water walls, a novel passive concept in which a supported water wall absorbs gases from the I cabin atmosphere for provision to algae [24].…”

Compact, Lightweight Adsorber and Sabatier Reactor for CO2 Capture and Reduction for Consumable and Propellant Production

“…26 These units were designed to provide the required removal rate of metabolic-generated CO 2 for one crew member (i.e., 1 kg CO 2 /day) and have been characterized by NASA Marshall. Utilizing the sub-scale test data furnished by NASA Marshall, PCI scaled-up and sized the required adsorbent beds for the CO 2 removal module and the moisture American Institute of Aeronautics and Astronautics 6 removal module for the targeted 4-crew member.…”

“…26 Then, for each adsorber module, the housing dimension was optimized to achieve maximum overall volumetric efficiency with uniform reactant flow distribution and minimal recirculation zones. A total of four full-scale adsorber modules, consisting of two CO 2 adsorber modules and two moisture removal modules, were delivered to NASA Marshall for performance validation.…”