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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS2006

Rapid Cycling CO2 and H2O Removal System for EMU

NASA's planned future missions set stringent demands on the design of the Portable Life Support Systems (PLSS), requiring dramatic reductions in weight, decreased reliance on supplies and greater flexibility on the types of missions. Use of regenerable systems that reduce weight and volume of the EMU is of critical importance to NASA, both for low orbit operations and for long duration manned missions. The CO2 and humidity control unit in the existing PLSS design is relatively large, since it has to remove 8 hours worth of CO2. If the sorbent regeneration can be carried out during the extravehicular activity (EVA) with a relatively high regeneration frequency, the size of the sorbent canister and weight can be significantly reduced. TDA Research, Inc. (TDA) is developing a compact, regenerable sorbent-based system to control CO2 and humidity in the space suit ventilation loop. The sorbent can be regenerated using space vacuum during the EVA, eliminating all duration-limiting elements in the life support system. This paper summarizes the results of the sorbent development and testing, and evaluation efforts. The results of a preliminary system analysis are also included, showing the size and volume reductions provided by the new system.

Alptekin, Gokhan↗
NASA NTRS2017

Development of Trace Contaminant Control Prototypes for the Primary Life Support System (PLSS)

Results are presented on the development of Trace Contaminant Control (TCC) Prototypes for use in Extravehicular Activities (EVAs), and more specifically in the Primary Life Support System (PLSS). The current TC-control technology involves the use of a packed bed of acid-impregnated granular charcoal, which is non-regenerable, and the carbon-based sorbent under development in this project can be regenerated by exposure to vacuum at room temperature. Data on sorption and desorption of ammonia and formaldehyde, which are major TCs of concern, as well as pressure-drop calculations were used to design and test 1/6-scale and full-scale trace contaminant control system (TCCS) prototypes. Carbon sorbents were fabricated in both the granular and foam-supported forms. Sorbent performance was tested for ammonia sorption and vacuum regeneration in 1/6-scale, and pressure-drop characteristics were measured at flow rates relevant to the PLSS application.

Wojtowicz, Marek↗
NASA NTRS2008

Development and Testing of a Sorbent-Based Atmosphere Revitalization System for the Crew Exploration Vehicle 2007/2008

The design of a Vacuum-Swing Adsorption (VSA) system to remove metabolic water and metabolic carbon dioxide from the Orion Crew Exploration Vehicle (CEV) atmosphere is presented. The approach for Orion is a VSA system that removes not only 100 percent of the metabolic CO2 from the atmosphere, but also 100% of the metabolic water as well, a technology approach that has not been used in previous spacecraft life support systems. The design and development of the Sorbent Based Atmosphere Regeneration (SBAR) system, including test articles, a facility test stand, and full-scale testing in late 2007 and early 2008 is discussed.

Knox, James C.↗
NASA NTRS2016

Development of a Microwave Regenerative Sorbent-Based Hydrogen Purifier

This paper describes the design and fabrication of a Microwave Regenerative Sorbent-based Hydrogen Purifier (MRSHP). This unique microwave powered technology was developed for the purification of a hydrogen stream produced by the Plasma Pyrolysis Assembly (PPA). The PPA is a hydrogen recovery (from methane) post processor for NASA's Sabatier-based carbon dioxide reduction process. Embodied in the Carbon dioxide Reduction Assembly (CRA), currently aboard the International Space Station (ISS), the Sabatier reaction employs hydrogen to catalytically recover oxygen, in the form of water, from respiratory carbon dioxide produced by the crew. This same approach is base-lined for future service in the Air Revitalization system on extended missions into deep space where resupply is not practical. Accordingly, manned exploration to Mars may only become feasible with further closure of the air loop as afforded by the greater hydrogen recovery permitted by the PPA with subsequent hydrogen purification. By utilizing the well-known high sorbate loading capacity of molecular sieve 13x, coupled with microwave dielectric heating phenomenon, MRSHP technology is employed as a regenerative filter for a contaminated hydrogen gas stream. By design, freshly regenerated molecular sieve 13x contained in the MRSHP will remove contaminants from the effluent of a 1-CM scale PPA for several hours prior to breakthrough. By reversing flow and pulling a relative vacuum the MRSHP prototype then uses 2.45 GHz microwave power, applied through a novel coaxial antenna array, to rapidly heat the sorbent bed and drive off the contaminants in a short duration vacuum/thermal contaminant desorption step. Finally, following rapid cooling via room temperature cold plates, the MRSHP is again ready to serve as a hydrogen filter.

Wheeler, Richard R., Jr.↗
NASA NTRSDate not supplied

Ammonia-Removal Efficiency By Full-Scale Carbon-Based Trace-Contaminant Sorbent Monoliths Integrated With the Rapid-Cycle Amine (RCA) Swing Bed

Results are presented on full-scale performance testing of vacuum-regenerable, carbon based sorbent monoliths for trace-contaminant (TC) removal integrated with the Rapid-Cycle Amine (RCA) swing bed for use in the Portable Life Support System (PLSS) during Extravehicular Activities (EVAs). The current state-of-art in TC-control technology involves the use of a packed bed of acid-impregnated granular charcoal, which is difficult to regenerate. The carbon-based sorbent under development in this project can be regenerated by exposure to vacuum at room temperature. Data on cyclic sorption-desorption of ammonia, which is a major TC of concern, were collected in a simulated PLSS ventilation loop which involved the RCA placed upstream of the Trace Contaminant Control System (TCCS). Results of testing involving pressure-swing operation of the integrated TCCS/RCA system indicate ammonia-removal efficiency exceeding 80% throughout multiple sorption-desorption cycles. This paper presents an overview of the TCCS research, the favorable results obtained, and provides insight into future work needed to further the technology development.

Marek A Wójtowicz↗
NASA NTRS2006

Development and Testing of a Sorbent-Based Atmosphere Revitalization System for the Crew Exploration Vehicle

The design of a vacuum-swing adsorption process to remove metabolic water, metabolic carbon dioxide, and metabolic and equipment generated trace contaminant gases from the Crew Exploration Vehicle (CEV) atmosphere is presented. For the CEV, the approach is taken that all metabolic water must be removed by the Sorbent-Based Atmosphere Revitalization System (SBAR), a technology approach that has not been used in previous spacecraft life support systems. Design and development of a prototype SBAR, a facility test stand, and subsequent testing of the SBAR is discussed.

Knox, James C.↗
NASA NTRS2016

Co-Adsorption of Ammonia and Formaldehyde on Regenerable Carbon Sorbents for the Primary Life Support System (PLSS)

Results are presented on the development of a reversible carbon sorbent for trace-contaminant (TC) removal for use in Extravehicular Activities (EVAs), and more specifically in the Primary Life Support System (PLSS). The current TC-control technology involves the use of a packed bed of acid-impregnated granular charcoal, which is deemed non-regenerable, while the carbon-based sorbent under development in this project can be regenerated by exposure to vacuum at room temperature. Data on concurrent sorption and desorption of ammonia and formaldehyde, which are major TCs of concern, are presented in this paper. A carbon sorbent was fabricated by dry impregnation of a reticulated carbon-foam support with polyvinylidene chloride, followed by carbonization and thermal oxidation in air. Sorbent performance was tested for ammonia and formaldehyde sorption and vacuum regeneration, with and without water present in the gas stream. It was found that humidity in the gas phase enhanced ammonia-sorption capacity by a factor larger than two. Co-adsorption of ammonia and formaldehyde in the presence of water resulted in strong formaldehyde sorption (to the point that it was difficult to saturate the sorbent on the time scales used in this study). In the absence of humidity, adsorption of formaldehyde on the carbon surface was found to impair ammonia sorption in subsequent runs; in the presence of water, however, both ammonia and formaldehyde could be efficiently removed from the gas phase by the sorbent. The efficiency of vacuum regeneration could be enhanced by gentle heating to temperatures below 60 deg.

Wojtowicz, Marek A.↗
NASA NTRS2007

High-Temperature Desulfurization of Heavy Fuel-Derived Reformate Gas Streams for SOFC Applications

Desulfurization of the hot reformate gas produced by catalytic partial oxidation or autothermal reforming of heavy fuels, such as JP-8 and jet fuels, is required prior to using the gas in a solid oxide fuel cell (SOFC). Development of suitable sorbent materials involves the identification of sorbents with favorable sulfidation equilibria, good kinetics, and high structural stability and regenerability at the SOFC operating temperatures (650 to 800 C). Over the last two decades, a major barrier to the development of regenerable desulfurization sorbents has been the gradual loss of sorbent performance in cyclic sulfidation and regeneration at such high temperatures. Mixed oxide compositions based on ceria were examined in this work as regenerable sorbents in simulated reformate gas mixtures and temperatures greater than 650 C. Regeneration was carried out with dilute oxygen streams. We have shown that under oxidative regeneration conditions, high regeneration space velocities (greater than 80,000 h(sup -1)) can be used to suppress sulfate formation and shorten the total time required for sorbent regeneration. A major finding of this work is that the surface of ceria and lanthanan sorbents can be sulfided and regenerated completely, independent of the underlying bulk sorbent. This is due to reversible adsorption of H2S on the surface of these sorbents even at temperatures as high as 800 C. La-rich cerium oxide formulations are excellent for application to regenerative H2S removal from reformate gas streams at 650 to 800 C. These results create new opportunities for compact sorber/regenerator reactor designs to meet the requirements of solid oxide fuel cell systems at any scale.

Flytzani-Stephanopoulos, Maria↗
NASA NTRS2011

Performance Evaluation of Engineered Structured Sorbents for Atmosphere Revitalization Systems On Board Crewed Space Vehicles and Habitats

Engineered structured (ES) sorbents are being developed to meet the technical challenges of future crewed space exploration missions. ES sorbents offer the inherent performance and safety attributes of zeolite and other physical adsorbents but with greater structural integrity and process control to improve durability and efficiency over packed beds. ES sorbent techniques that are explored include thermally linked and pressure-swing adsorption beds for water-save dehumidification and sorbent-coated metal meshes for residual drying, trace contaminant control, and carbon dioxide control. Results from sub-scale performance evaluations of a thermally linked pressure-swing adsorbent bed and an integrated sub-scale ES sorbent system are discussed.

Howard, David F.↗
NASA NTRS2015

NASA - Johnson Space Center's New Capabilities for Air Purification

NASA has some unique and challenging air purification problems that cannot be adequately met with COTS technology: 1) ammonia removal from air, 2) hydrazine removal from air, 3) CO conversion to CO2 in low temperature, high humidity environments. NASA has sponsored the development of new sorbents and new catalysts. These new sorbents and catalysts work better than COTS technology for our application. If attendees have a need for an effective ammonia sorbent, an effective hydrazine sorbent, or an effective CO conversion catalyst, we should learn to see if NASA sponsored technology development can help.

Graf, John↗
NASA NTRS2010

Carbon Dioxide Control System for a Mars Space Suit Life Support System

Carbon dioxide (CO2) control during Extravehicular Activities (EVAs) on Mars will be challenging. Lithium hydroxide (LiOH) canisters have impractical logistics penalties, and regenerable metal oxide (MetOx) canisters weigh too much. Cycling bed systems and permeable membranes that are regenerable in space vacuum cannot vent on Mars due to the high partial pressure of CO2 in the atmosphere. Although sweep gas regeneration is under investigation, the feasibility, logistics penalties, and failure modes associated with this technique have not been fully determined. TDA Research, Inc. is developing a durable, high-capacity regenerable adsorbent that can remove CO2 from the space suit ventilation loop. The system design allows sorbent regeneration at or above 6 torr, eliminating the potential for Martian atmosphere to leak into the regeneration bed and into the ventilation loop. Regeneration during EVA eliminates the consumable requirement related to the use of LiOH canisters and the mission duration limitations imposed by MetOx system. The concept minimizes the amount of consumable to be brought from Earth and makes the mission more affordable, while providing great operational flexibility during EVA. The feasibility of the concept has been demonstrated in a series of bench-scale experiments and a preliminary system analysis. Results indicate that sorbent regeneration can be accomplished by applying a 14 C temperature swing, while regenerating at 13 torr (well above the Martian atmospheric pressure), withstanding over 1,000 adsorption/regeneration cycles. This paper presents the latest results from these sorbent and system development efforts.

Alptekin, Gokhan↗
NASA NTRS2011

Carbon Dioxide Control System for a Mars Space Suit Life Support System

Carbon dioxide (CO2) control during Extravehicular Activities (EVAs) on Mars will be challenging. Lithium hydroxide (LiOH) canisters have impractical logistics penalties, and regenerable metal oxide (MetOx) canisters weigh too much. Cycling bed systems and permeable membranes that are regenerable in space vacuum cannot vent on Mars due to the high partial pressure of CO2 in the atmosphere. Although sweep gas regeneration is under investigation, the feasibility, logistics penalties, and failure modes associated with this technique have not been fully determined. TDA Research, Inc. is developing a durable, high-capacity regenerable adsorbent that can remove CO2 from the space suit ventilation loop. The system design allows sorbent regeneration at or above 6 torr, eliminating the potential for Martian atmosphere to leak into the regeneration bed and into the ventilation loop. Regeneration during EVA minimizes the amount of consumables to be brought from Earth and makes the mission more affordable, while providing great operational flexibility during EVA. The feasibility of the concept has been demonstrated in a series of bench-scale experiments and a preliminary system analysis. This paper presents the latest results from these sorbent and system development efforts.

Alptekin, Gokhan↗
NASA NTRSDate not supplied

Improvements in Ionic Liquid Technology for Carbon Dioxide Removal Applications

Carbon dioxide removal from cabin air continues to be of vital importance for future space missions. Current and proposed approaches have employed solid sorbents, hollow fiber membrane separators, and direct liquid sorbent contactors. Recent developments in ionic liquids have potential to improve performance in all three of these technologies. Efficient encapsulation of ionic liquids by polymeric shell can enable their use in a solid sorbent-like configuration without significant integration intervention to the current space technology. Poly(ionic liquid)-ionic liquid membranes have the potential to cross over the Robeson selectivity-permeability upper bound, and thereby outperform traditional membranes used in hollow fibers. Advances in ionic liquid chemistry enables performance improvements in liquid sorbent contactors owing to the tunable gravimetric CO2 capacity, reaction enthalpy and liquid viscosity. This paper will describe recent work in each of these areas.

Ionic Liquid,Carbon Dioxide,Air Revitalization↗
NASA NTRS2019

Monolithic Trace-Contaminant Sorbents Fabricated from 3D-Printed Polymer Precursors

The current trace-contaminant (TC) removal technology for use in Extravehicular Activities (EVAs) involves the use of a packed bed of acid-impregnated granular charcoal, which is difficult to regenerate. In this paper, results are presented on the development of vacuum-regenerable TC sorbents for use in the Portable Life Support System (PLSS). The sorbents are derived from 3D-printed polymer monoliths (e.g., honeycomb structures), which are then carbonized and activated in order to develop porosity, and also to enhance the TC-sorption capacity. Results are presented on the following aspects of carbon-sorbent development: (1) precursor selection; (2) monolith fabrication; (3) shape retention and strength; (4) carbon surface and porosity characterization; (5) TC-sorption capacity and vacuum-regeneration; (6) pressure drop; and (7) sub-scale sorbent prototype. The use of predominantly microporous monolithic carbon is associated with the following benefits: (a) high TC-sorption capacity; (b) low pressure drop; (c) rapid vacuum (pressure-swing) desorption due to thin monolith walls and low pressure drop; (d) good thermal management (high thermal conductivity and low adsorption/desorption thermal effects associated with physisorption); and (e) good resistance to dusty environments.

Portable Life Support System (PLSS)↗
NASA NTRS2011

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

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 CO2 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 CO2, 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 CO2 removal is also presented.

Junaedi, Christian↗
NASA NTRS2015

Development of a Test for Evaluation of the Hydrothermal Stability of Sorbents Used in Closed-Loop CO2 Removal Systems

The International Space Station Carbon Dioxide Removal Assembly uses zeolite 5A molecular sieve material packed into beds for the capture of cabin CO2. The beds are cyclically heated to drive off the CO2 and restore the removal capacity. Over time, the sorbent material has been found to break down resulting in dust that restricts flow through the beds. Humidity adsorbed in the 5A zeolite when it is heated is a suspected cause of this sorbent degradation. To evaluate the impact of adsorbed water during thermal cycling, the Hydrothermal Stability Test was developed. The test configuration provides comparative side-by-side flow restriction data for two sorbent materials at specifically controlled humidity levels. While the initial focus of the testing is on 5A zeolite materials currently used on the ISS, the system will also be used to evaluate future candidate materials. This paper describes the approach, the test system, current results, and future testing.

Knox, James C.↗
NASA NTRS2006

Development and Verification of a Finite-Difference Model of the Sorbent-Based Atmosphere Revitalization System for the Crew Exploration

A vacuum-swing adsorption (VSA) process to remove metabolic water, metabolic carbon dioxide, and metabolic and equipment generated trace contaminant gases from the Crew Exploration Vehicle (CEV) atmosphere is being designed. For the CEV, the approach is taken that all metabolic water must be removed by the Sorbent-Based Atmosphere Revitalization System (SBAR), a technology approach that has not been used in previous spacecraft life support systems. To support the design of the SBAR, a Finite Difference computer model has been developed. In addition, examination of the competitive adsorption aspects of water and carbon dioxide on various sorbents is being investigated in order to both refine the computer simulation and gain understanding of the VSA process

Ritter, James↗