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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 163 records · Page 9

(abstract) Development of Sorbent Bed Assembly for a Periodic 10K Solid Hydrogen Cryocooler

A closed-cycle 10K sorption cryocooler is being fabricated for microgravity testing during a future space shuttle mission. A critical component of this cryogenic refrigerator is the metal hydride sorbent bed assembly (SBA). The SBA uses hydrides which absorb hydrogen gas at low pressure, (i.e., about 0.25 MPa from liquid hydrogen at 25K and below 0.2 kPa from solid hydrogen near 10K) and subsequently delivers hydrogen at nearly 10 MPa to a storage reservoir to repeat the Joule-Thomson (J-T) expansion process. The SBA includes three independent hydride beds where two contain LaNi(sub 4.8)Sn(sub 0.2) alloy and the third ZrNi. Detailed descriptions will be given for the three beds, which have specialized design features to enhance performance at each step of operation. In particular, two beds must rapidly absorb hydrogen in order for the J-T cold stage to reach 10K within two minutes from a 65K holding temperature. Performance characterization results will be compared to model analyses of the SBA.

applications microgravity↗

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.↗

Characteristics of Post-Sorbent and High Temperature Catalytic Oxidizer Beds After Long-Term On-Orbit Use

Trace contaminants are produced on-orbit by human metabolic processes and equipment off-gassing. These potentially hazardous contaminants are removed by the Trace Contaminant Control Subassembly (TCCS) in the US segment of the International Space Station (ISS). The TCCS has been operating since February 2001. Analysis of on-orbit telemetry data indicated a slow increase in the TCCS system flow resistance over the five years of operation. Two of the packed beds within the TCCS were replaced to return the TCCS to its nominal operation conditions; the high temperature catalytic oxidizer and the post-sorbent bed. Results from the examination of the returned beds are presented along with a discussion about changes to bed service life.

Johnson, Sharon↗

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.↗

Design and Performance of the Sorbent-Based Atmosphere Revitalization System for Orion

Validation and simulations of a real-time dynamic cabin model were conducted on the sorbent-based atmosphere revitalization system for Orion. The dynamic cabin model, which updates the concentration of H2O and CO2 every second during the simulation, was able to predict the steady state model values for H2O and CO2 for long periods of steady metabolic production for a 4-person crew. It also showed similar trends for the exercise periods, where there were quick changes in production rates. Once validated, the cabin model was used to determine the effects of feed flow rate, cabin volume and column volume. A higher feed flow rate reduced the cabin concentrations only slightly over the base case, a larger cabin volume was able to reduce the cabin concentrations even further, and the lower column volume led to much higher cabin concentrations. Finally, the cabin model was used to determine the effect of the amount of silica gel in the column. As the amount increased, the cabin concentration of H2O decreased, but the cabin concentration of CO2 increased.

Ritter, James A.↗

Development and Testing of a Sorbent-Based Atmosphere Revitalization System 2010/2011

Spacecraft being developed for future exploration missions incorporate Environmental Control and Life Support Systems (ECLSS) that limit weight, power, and volume thus requiring systems with higher levels of efficiency while maintaining high dependability and robustness. For air revitalization, an approach that meets those goals utilizes a regenerative Vacuum-Swing Adsorption (VSA) system that removes 100% of the CO2 from the cabin atmosphere as well as 100% of the water. A Sorbent Based Atmosphere Revitalization (SBAR) system is a VSA system that utilizes standard commercial adsorbents that have been proven effective and safe in spacecraft including Skylab and the International Space Station. The SBAR system is the subject of a development, test, and evaluation program that is being conducted at NASA s Marshall Space Flight Center. While previous testing had validated that the technology is a viable option, potential improvements to system design and operation were identified. Modifications of the full-scale SBAR test articles and adsorption cycles have been implemented and have shown significant performance gains resulting in a decrease in the consumables required for a mission as well as improved mission safety. Previous testing had utilized single bed test articles, during this period the test facility was enhanced to allow testing on the full 2-bed SBAR system. The test facility simulates a spacecraft ECLSS and allows testing of the SBAR system over the full range of operational conditions using mission simulations that assess the real-time performance of the SBAR system during scenarios that include the metabolic transients associated with extravehicular activity. Although future manned missions are currently being redefined, the atmosphere revitalization requirements for the spacecraft are expected to be quite similar to the Orion and the Altair vehicles and the SBAR test program addressed validation to the defined mission requirements as well as operation in other potential vehicle architectures. The development program, including test articles, the test facility, and tests and results through early 2011 is discussed.

Miller, Lee A.↗

Investigation of Desiccants and CO2 Sorbents for Advanced Exploration Systems 2016-2017

Advanced Environmental Control and Life Support System (ECLSS) design is critical for manned space flight beyond Earth. Current systems enable extended missions in low-Earth orbit, but for deep-space missions, not only will astronauts be outside the reach of resupply operations from Earth but they will also need to handle malfunctions and compensate for the degradation of materials. These two daunting challenges must be overcome for long-term independent space flight. In order to solve the first, separation and recycling of onboard atmosphere is required. Current systems utilize space vacuum to fully regenerate CO2 sorbent beds, but this is not sustainable. The second challenge stems from material and performance degradation due to operational cycling and on-board contaminants. This report will review the recent work by the ECLSS team at Marshall Space Flight Center towards overcoming these challenges by characterizing materials via novel methods and by assessing new air revitalization systems.

Knox, Jim↗

Sorbent-Based Atmosphere Revitalization System

The present invention is a sorbent-based atmosphere revitalization (SBAR) system using treatment beds each having a bed housing, primary and secondary moisture adsorbent layers, and a primary carbon dioxide adsorbent layer. Each bed includes a redirecting plenum between moisture adsorbent layers, inlet and outlet ports connected to inlet and outlet valves, respectively, and bypass ports connected to the redirecting plenums. The SBAR system also includes at least one bypass valve connected to the bypass ports. An inlet channel connects inlet valves to an atmosphere source. An outlet channel connects the bypass valve and outlet valves to the atmosphere source. A vacuum channel connects inlet valves, the bypass valve and outlet valves to a vacuum source. In use, one bed treats air from the atmosphere source while another bed undergoes regeneration. During regeneration, the inlet, bypass, and outlet valves sequentially open to the vacuum source, removing accumulated moisture and carbon dioxide.

Knox, James C↗

Characterization of Sorbents for Controlling Ammonia in Spacecraft Cabin Air

The trace contaminant control system (TCCS) utilizes packed beds of Barnebey-Sutcliffe (B-S) Type 3032 to remove ammonia from ISS (International Space Station) cabin air. BS Type 3032, an acid-impregnated activated carbon, is no longer produced and must be replaced. The adsorptive capacities of Calgon Carbon Ammonasorb II and Molecular Products Chemsorb® 1425 for ammonia were measured using moist (40% RH (Relative Humidity)) spacecraft simulated gas streams. These candidate replacement sorbents had 66% greater ammonia removal capacities at low (5 ppm) ammonia concentrations than B-S Type 3032.

Monje, Oscar↗

Zeolite Degradation: An Investigation of CO2 Capacity Loss of 13x Sorbent

System testing of the Carbon Dioxide Removal and Compression System (CRCS) has revealed that sufficient CO2 removal capability was not achieved with the designed system. Subsystem component analysis of the zeolite bed revealed that the sorbent material suffered significant degradation and CO2 loading capacity loss. In an effort to find the root cause of this degradation, various factors were investigated to try to reproduce the observed performance loss. These factors included contamination by vacuum pump oil, o-ring vacuum grease, loadingunloading procedures, and operations. This paper details the experiments that were performed and their results.

ECLSS↗

Redesign of Carbon Dioxide Removal System for Multifunctional Sorbent Bed Testing

Carbon dioxide removal is a key function of Environmental Control and Life Support System (ECLSS) on the International Space System (ISS). Currently, this system uses pellet beds however they have known issues such as flow channeling and uneven heating. The Multifunction Sorbent (MultiSorb) project is developing 3D-printed zeolite beds with embedded heaters to address these issues. This poster lays out the steps in modifying the Carbon Dioxide Removal and Compression System (CRCS) to test the MultiSorb beds.

MultiSORB↗

Unveiling the porosity effect of superbase ionic liquid-modified carbon sorbents in CO 2 capture from air

Direct air capture (DAC) of CO 2 represents one of the most promising technologies to achieve negative carbon emissions. In this work, the superbase ionic liquids (ILs)-modified carbon substrates were developed for DAC of CO 2 by harnessing the strong CO 2 binding capability of IL and the ordered porous channels of the carbon supports. Detailed porosity analysis revealed that the IL with an aromatic cation and an oxygenate anion preferred to fill the micropores, and a thin layer was created on the surface of the mesopores. Strong π-π interaction between the IL layer and the carbon surface was disclosed by wide-angle X-ray scattering (WAXS) analysis, leading to enhanced thermal stability of the IL phase. For the same lL coating amount, the DAC of CO 2 evaluation revealed that a larger mesopore size and pore volume in the carbon/IL composite materials led to higher CO 2 uptake capacity by exposing more active sites to integrate CO 2 from diluted sources. Further, the thermodynamic analysis confirmed the critical role of IL coating in providing strong chemisorption sites and significantly improved selectivity to enrich the diluted CO 2 from the air atmosphere. This work provides guidance on leveraging the scaffolds' surface properties and porosities of the scaffolds to optimize DAC of CO 2 behavior.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Spatially Mapping the CO 2 Alkaline Sorbent Diffuse Microenvironment Using Operando Raman Spectroscopy

When designing a chemical process, the local balance of transport and kinetics, collectively referred to as the diffuse microenvironment, plays a critical role in performance but is difficult to directly observe. This work demonstrates a method of two-dimensional spatial chemical mapping of the diffuse microenvironment in the context of alkali metal hydroxide direct air capture of carbon dioxide using a custom operando gas-absorption flow cell along with confocal Raman spectroscopy. Notably, we observe the concentration boundary layer near the gas–liquid interface and elucidate the interplay of carbonate and bicarbonate ions within it while inferring local hydroxide depletion through continuum modeling. These first of their kind observations provide a technique to compare the performance of direct air capture solvents based on diffuse microenvironment dynamics while also providing metrics important for air contactor design such as boundary layer thickness. Overall, this work showcases a new experimental platform to study interfacial diffuse microenvironments in and outside of the field of direct air capture of carbon dioxide.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗