Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “Sorbent”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS2015

Sorbent Structural Impacts Due to Humidity on Carbon Dioxide Removal Sorbents for Advanced Exploration Systems

The Life Support Systems Project (LSSP) under the Advanced Exploration Systems (AES) program builds upon the work performed under the AES Atmosphere Resource Recovery and Environmental Monitoring (ARREM) project focusing on the numerous technology development areas. The CO2 removal and associated air drying development efforts are focused on improving the current state-of-the-art system on the International Space Station (ISS) utilizing fixed beds of sorbent pellets by seeking more robust pelletized sorbents, evaluating structured sorbents, and examining alternate bed configurations to improve system efficiency and reliability. A component of the CO2 removal effort encompasses structural stability testing of existing and emerging sorbents. Testing will be performed on dry sorbents and sorbents that have been conditioned to three humidity levels. This paper describes the sorbent structural stability screening efforts in support of the LSS Project within the AES Program.

Watson, David↗
NASA NTRS2016

Sorbent Structural Testing on Carbon Dioxide Removal Sorbents for Advanced Exploration Systems

Long term space missions require carbon dioxide removal systems that can function with minimal downtime required for maintenance, low power consumption and maximum efficiency for CO2 removal. A major component of such a system are the sorbents used for the CO2 and desiccant beds. Sorbents must not only have adequate CO2 and H2O removal properties, but they must have the mechanical strength to prevent structural breakdown due to pressure and temperature changes during operation and regeneration, as well as resistance to breakdown due to moisture in the system from cabin air. As part of the studies used to select future CO2 sorbent materials, mechanical tests are performed on various zeolite sorbents to determine mechanical performance while dry and at various humidified states. Tests include single pellet crush, bulk crush and attrition tests. We have established a protocol for testing sorbents under dry and humid conditions, and previously tested the sorbents used on the International Space Station carbon dioxide removal assembly. This paper reports on the testing of a series of commercial sorbents considered as candidates for use on future exploration missions.

Watson, David↗
NASA NTRS1973

CO2 removal by solid amine sorbents. 1: Experimental studies of amine resin IR-45 with regard to spacecraft applications. 2: Computer program for predicting the transient performance of solid amine sorbent systems

The sorbent behavior of solid amine resin IR-45 with regard to potential use in regenerative CO2-removal systems for manned spacecraft is considered. Measurements of equilibrium sorption capacity of IR-45 for water and for CO2 are reported, and the dynamic mass transfer behavior of IR-45 beds is studied under conditions representative of those expected in a manned spacecraft. A digital computer program was written for the transient performance prediction of CO2 removal systems comprised of solid amine beds. Also evaluated are systems employing inorganic molecular-sieve sorbents. Tests show that there is definitely an effect of water loading on the absorption rate.

Wright, R. M.↗
NASA NTRS2013

Regenerable Sorbent for CO2 Removal

A durable, high-capacity regenerable sorbent can remove CO2 from the breathing loop under a Martian atmosphere. The system design allows near-ambient temperature operation, needs only a small temperature swing, and sorbent regeneration takes place at or above 8 torr, eliminating the potential for Martian atmosphere to leak into the regeneration bed and into the breathing loop. The physical adsorbent can be used in a metabolic, heat-driven TSA system to remove CO2 from the breathing loop of the astronaut and reject it to the Martian atmosphere. Two (or more) alternating sorbent beds continuously scrub and reject CO2 from the spacesuit ventilation loop. The sorbent beds are cycled, alternately absorbing CO2 from the vent loop and rejecting the adsorbed material into the environment at a high CO2 partial pressure (above 8 torr). The system does not need to run the adsorber at cryogenic temperatures, and uses a much smaller temperature swing. The sorbent removes CO2 via a weak chemical interaction. The interaction is strong enough to enable CO2 adsorption even at 3 to 7.6 torr. However, because the interaction between the surface adsorption sites and the CO2 is relatively weak, the heat input needed to regenerate the sorbent is much lower than that for chemical absorbents. The sorbent developed in this project could potentially find use in a large commercial market in the removal of CO2 emissions from coal-fired power plants, if regulations are put in place to curb carbon emissions from power plants.

Alptekin, Gokhan↗
NASA NTRSDate not supplied

Trace Contaminant Control Test Bed for Evaluation of TCC Prototypes with Vacuum Regenerable and Non-Regenerable Sorbents

A new Space Suit Exploration Portable Life Support System (xPLSS) is being designed, built, integrated, and tested into the Extra-Vehicular Mobility Unit (xEMU). The Trace Contaminant Control (TCC) system is a component in the oxygen ventilation loop of xPLSS that removes contaminants generated by the crewmembers’ metabolic processes. The primary trace contaminants that must be removed include ammonia (NH3), carbon monoxide (CO), formaldehyde (CH2O), and methyl mercaptan (CH3SH). The current state-of-the-art TCC sorbent is non-regenerable activated carbon. As a non-regenerable sorbent, its use negatively impacts the logistics for future missions. Thus, an ideal solution can be a vacuum-regenerable sorbent integrated with the xPLSS CO2/H2O removal system. To test new designs and sorbents, XploSafe has constructed a recirculating test bed that mimics the environment within the xPLSS by providing concentrations of the trace contaminant analytes generated at the operating temperature, humidity, pressure, and flow rates of the xPLSS. This system can perform regeneration or desorption by exposing the sorbent to a pressure swing from 4.3 psia to <1 torr over approximately 2 minutes. Using this test system, XploSafe evaluated various TCC prototypes constructed using rapid prototyping techniques and identified a process that allows vacuum regenerative TCC designs to be quickly examined for flow, pressure drop, and performance. By using toluene as a segregate for volatile organics, this test system was evaluated using both vacuum regenerable and non-regenerable sorbents to demonstrate the operational effectiveness of these sorbents in maintaining the concentrations of the trace contaminant analytes below the 7-day Spacecraft Maximum Allowable Concentrations.

Nicholas Materer↗
NASA NTRS2017

CO2 Capacity Sorbent Analysis Using Volumetric Measurement Approach

In support of air revitalization system sorbent selection for future space missions, Ames Research Center (ARC) has performed CO2 capacity tests on various solid sorbents to complement structural strength tests conducted at Marshall Space Flight Center (MSFC). The materials of interest are: Grace Davison Grade 544 13X, Honeywell UOP APG III, LiLSX VSA-10, BASF 13X, and Grace Davison Grade 522 5A. CO2 capacity was for all sorbent materials using a Micromeritics ASAP 2020 Physisorption Volumetric Analysis machine to produce 0C, 10C, 25C, 50C, and 75C isotherms. These data are to be used for modeling data and to provide a basis for continued sorbent research. The volumetric analysis method proved to be effective in generating consistent and repeatable data for the 13X sorbents, but the method needs to be refined to tailor to different sorbents.

Air Revitalization↗
NASA NTRS2016

Investigation of Desiccants and CO2 Sorbents for Advanced Exploration Systems 2015-2016

Design of advanced carbon dioxide removal systems begins with the study of sorbents. Specifically, new CO2 sorbents and desiccants need to be studied to enable greater productivity from existing and future spaceflight systems. This presentation will discuss the studies used as input for selecting future CO2 sorbent materials. Also, the adjoining issues of understanding the effects of water co-adsorption and material selection for desiccant beds will be discussed. Current sorbents for CO2 removal are based on 5A zeolites, but a transition to sorbents derived from 13X will be necessary as CO2 levels in cabin air become leaner. Unfortunately, these 13X zeolites are more susceptible to long-term performance loss due to water co-adsorption than 5A due at achievable regeneration temperatures. A study on how impactful the presence of trace water will be to the cyclic operation of small-scale beds will be discussed. Also, methods to recover the performance of beds in a space environment after a major moisture adsorption event will be discussed. The information obtained from the water co-adsorption studies will play a major part in selecting a CO2 sorbent for advanced removal systems. Pellet structural properties play another major role in the selection process. One factor for long-term, hands-off operation of a system is pellet integrity. Maintaining integrity means preventing pellet fracture and the generation of fines due to various thermal and mechanical means which would eventually clog filters or damage downstream systems. Either of these problems require significant shutdowns and maintenance operations and must be avoided. Therefore, study of high-integrity pellets and design of new pellets will be 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 NTRS2017

CO2 Capacity Sorbent Analysis Using Volumetric Measurement Approach

In support of air revitalization system sorbent selection for future space missions, Ames Research Center (ARC) has performed CO2 capacity tests on various solid sorbents to complement structural strength tests conducted at Marshall Space Flight Center (MSFC). The materials of interest are: Grace Davison Grade 544 13X, Honeywell UOP APG III, LiLSX VSA-10, BASF 13X, and Grace Davison Grade 522 5A. CO2 capacity was for all sorbent materials using a Micromeritics ASAP 2020 Physisorption Volumetric Analysis machine to produce 0 C, 10 C, 25 C, 50 C, and 75 C isotherms. These data are to be used for modeling data and to provide a basis for continued sorbent research. The volumetric analysis method proved to be effective in generating consistent and repeatable data for the 13X sorbents, but the method needs to be refined to tailor to different sorbents.

Huang, Roger↗
NASA NTRS2007

Development of a Rapid Cycling CO(sub 2) and H(sub 2)O Removal Sorbent

The National Aeronautics and Space Administration (NASA) planned future missions set stringent demands on the design of the Portable Life Support System (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 Extravehicular Mobility Unit (EMU) is of critical importance to NASA, both for low orbit operations and for long duration manned missions. The carbon dioxide and humidity control unit in the existing PLSS design is relatively large, since it has to remove and store 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. The progress of regenerable CO2 and humidity control is leading us towards the use of a rapid cycling amine system. TDA Research, Inc. is developing compact, regenerable sorbent materials to control CO2 and humidity in the space suit ventilation loop. The sorbent can be regenerated using space vacuum during the EVA, eliminating all carbon dioxide and humidity duration-limiting elements in the life support system. The material also has applications in other areas of space exploration such as the Orion spacecraft and other longer duration exploration missions requiring regenerable technologies. This paper summarizes the results of the sorbent development, testing, and evaluation efforts to date. The results of a preliminary system analysis are also included, showing the size and volume reductions for PLSS provided by the new system.

Paul, Heather↗
NASA NTRS2007

Development of a Rapid Cycling CO2 and H2O Removal Sorbent

The National Aeronautics and Space Administration (NASA) planned future missions set stringent demands on the design of the Portable Life Support System (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 Extravehicular Mobility Unit (EMU) is of critical importance to NASA, both for low orbit operations and for long duration manned missions. The carbon dioxide and humidity control unit in the existing PLSS design is relatively large, since it has to remove and store eight hours worth of carbon dioxide (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. is developing compact, regenerable sorbent materials to control CO2 and humidity in the space suit ventilation loop. The sorbent can be regenerated using space vacuum during the EVA, eliminating all CO2 and humidity duration-limiting elements in the life support system. The material also has applications in other areas of space exploration including long duration exploration missions requiring regenerable technologies and possibly the Crew Exploration Vehicle (CEV) spacecraft. This paper summarizes the results of the sorbent development, testing, and evaluation efforts to date.

Alptekin, Gokhan↗
NASA NTRS1988

High temperature regenerative H.sub.2 S sorbents

Efficient, regenerable sorbents for removal of H.sub.2 S from high temperature gas streams comprise porous, high surface area particles. A first class of sorbents comprise a thin film of binary oxides that form a eutectic at the temperature of the gas stream coated onto a porous, high surface area refractory support. The binary oxides are a mixture of a Group VB or VIB metal oxide with a Group IB, IIB or VIII metal oxide such as a film of V-Zn-O, V-Cu-O, Cu-Mo-O, Zn-Mo-O or Fe-Mo-O coated on an alumina support. A second class of sorbents consist of particles of unsupported mixed oxides in the form of highly dispersed solid solutions of solid compounds characterized by small crystallite size, high porosity and relatively high surface area. The mixed oxide sorbents contain one Group IB, IIB or VIIB metal oxide such as copper, zinc or manganese and one or more oxides of Groups IIIA, VIB or VII such as aluminum, iron or molybdenum. The presence of iron or aluminum maintains the Group IB, IIB or VIIB metal in its oxidized state. Presence of molybdenum results in eutectic formation at sulfidation temperature and improves the efficiency of the sorbent.

Flytani-Stephanopoulos, Maria↗
NASA NTRS2010

Sorbent, Sublimation, and Icing Modeling Methods: Experimental Validation and Application to an Integrated MTSA Subassembly Thermal Model

This paper details the validation of modeling methods for the three core components of a Metabolic heat regenerated Temperature Swing Adsorption (MTSA) subassembly, developed for use in a Portable Life Support System (PLSS). The first core component in the subassembly is a sorbent bed, used to capture and reject metabolically produced carbon dioxide (CO2). The sorbent bed performance can be augmented with a temperature swing driven by a liquid CO2 (LCO2) sublimation heat exchanger (SHX) for cooling the sorbent bed, and a condensing, icing heat exchanger (CIHX) for warming the sorbent bed. As part of the overall MTSA effort, scaled design validation test articles for each of these three components have been independently tested in laboratory conditions. Previously described modeling methodologies developed for implementation in Thermal Desktop and SINDA/FLUINT are reviewed and updated, their application in test article models outlined, and the results of those model correlations relayed. Assessment of the applicability of each modeling methodology to the challenge of simulating the response of the test articles and their extensibility to a full scale integrated subassembly model is given. The independent verified and validated modeling methods are applied to the development of a MTSA subassembly prototype model and predictions of the subassembly performance are given. These models and modeling methodologies capture simulation of several challenging and novel physical phenomena in the Thermal Desktop and SINDA/FLUINT software suite. Novel methodologies include CO2 adsorption front tracking and associated thermal response in the sorbent bed, heat transfer associated with sublimation of entrained solid CO2 in the SHX, and water mass transfer in the form of ice as low as 210 K in the CIHX.

Bower, Chad↗
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 NTRS2014

Carbon-Based Regenerable Sorbents for the Combined Carbon Dioxide and Ammonia Removal for the Primary Life Support System (PLSS)

Results are presented on the development of reversible sorbents for the combined carbon dioxide and trace-contaminant (TC) removal for use in Extravehicular Activities (EVAs). Since ammonia is the most important TC to be captured, data on TC sorption presented in this paper are limited to ammonia, with results relevant to other TCs to be reported at a later time. The currently available life support systems use separate units for carbon dioxide, trace contaminants, and moisture control, and the long-term objective is to replace the above three modules with a single one. Furthermore, 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. The objective of this study was to demonstrate the feasibility of using carbon sorbents for the reversible, concurrent sorption of carbon dioxide and ammonia. Several carbon sorbents were fabricated and tested, and multiple adsorption/vacuum-regeneration cycles were demonstrated at room temperature, and also a carbon surface conditioning technique that enhances the combined carbon dioxide and ammonia sorption without impairing sorbent regeneration.

Wojtowicz, Marek A.↗
NASA NTRS2004

Waste-Heat-Driven Cooling Using Complex Compound Sorbents

Improved complex-compound sorption pumps are undergoing development for use as prime movers in heat-pump systems for cooling and dehumidification of habitats for humans on the Moon and for residential and commercial cooling on Earth. Among the advantages of sorption heat-pump systems are that they contain no moving parts except for check valves and they can be driven by heat from diverse sources: examples include waste heat from generation of electric power, solar heat, or heat from combustion of natural gas. The use of complex compound sorbents in cooling cycles is not new in itself: Marketing of residential refrigerators using SrCl2 was attempted in the 1920s and 30s and was abandoned because heat- and mass-transfer rates of the sorbents were too low. Addressing the issue that gave rise to the prior abandonment of complex compound sorption heat pumps, the primary accomplishment of the present development program thus far has been the characterization of many candidate sorption media, leading to large increases in achievable heat- and mass-transfer rates. In particular, two complex compounds (called "CC260-1260" and "CC260-2000") were found to be capable of functioning over the temperature range of interest for the lunar-habitat application and to offer heat- and mass-transfer rates and a temperature-lift capability adequate for that application. Regarding the temperature range: A heat pump based on either of these compounds is capable of providing a 95-K lift from a habitable temperature to a heat-rejection (radiator) temperature when driven by waste heat at an input temperature .500 K. Regarding the heat- and mass-transfer rates or, more precisely, the power densities made possible by these rates: Power densities observed in tests were 0.3 kilowatt of cooling per kilogram of sorbent and 2 kilowatts of heating per kilogram of sorbent. A prototype 1-kilowatt heat pump based on CC260-2000 has been built and demonstrated to function successfully.

Rocketfeller, Uwe↗
NASA NTRS2016

Long Duration Sorbent Testbed

The Long Duration Sorbent Testbed (LDST) is a flight experiment demonstration designed to expose current and future candidate carbon dioxide removal system sorbents to an actual crewed space cabin environment to assess and compare sorption working capacity degradation resulting from long term operation. An analysis of sorbent materials returned to Earth after approximately one year of operation in the International Space Station's (ISS) Carbon Dioxide Removal Assembly (CDRA) indicated as much as a 70% loss of working capacity of the silica gel desiccant material at the extreme system inlet location, with a gradient of capacity loss down the bed. The primary science objective is to assess the degradation of potential sorbents for exploration class missions and ISS upgrades when operated in a true crewed space cabin environment. A secondary objective is to compare degradation of flight test to a ground test unit with contaminant dosing to determine applicability of ground testing.

Howard, David F.↗
NASA NTRS2017

Novel Liquid Sorbent C02 Removal System for Microgravity Applications

Removing Carbon Dioxide (CO2) from a spacecraft environment for deep space exploration requires a robust system that is low in weight, power, and volume. Current state-of-the-art microgravity compatible CO2 removal systems, such as the carbon dioxide removal assembly (CDRA), utilize solid sorbents that demand high power usage due to high desorption temperatures and a large volume to accommodate for their comparatively low capacity for CO2. Additionally, solid sorbent systems contain several mechanical components that significantly reduce reliability and contribute to a large overall mass. A liquid sorbent based system has been evaluated as an alternative is proposed to consume 65% less power, weight, and volume than solid based CO2 scrubbers. This paper presents the design of a liquid sorbent CO2 removal system for microgravity applications.

Rogers, Tanya↗