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At least 199 records · Page 11

Packing Optimization of Sorbent Bed Containing Dissimilar and Irregular Shaped Media

The Fire Cartridge is a packed bed air filter with two different and separate layers of media designed to provide respiratory protection from combustion products after a fire event on the International Space Station (ISS). The first layer of media is a carbon monoxide catalyst and the second layer of media is universal carbon. During development of Fire Cartridge prototypes, the two media beds were noticed to have shifted inside the cartridge. The movement of media within the cartridge can cause mixing of the bed layers, air voids, and channeling, which could cause preferential air flow and allow contaminants to pass through without removal. An optimally packed bed mitigates these risks and ensures effective removal of contaminants from the air. In order to optimally pack each layer, vertical, horizontal, and orbital agitations were investigated and a packed bulk density was calculated for each method. Packed bulk density must be calculated for each media type to accommodate variations in particle size, shape, and density. Additionally, the optimal vibration parameters must be re-evaluated for each batch of media due to variations in particle size distribution between batches. For this application it was determined that orbital vibrations achieve an optimal pack density and the two media layers can be packed by the same method. Another finding was media with a larger size distribution of particles achieve an optimal bed pack easier than media with a smaller size distribution of particles.

Holland, Nathan↗

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

Advanced Environmental Control and Life Support System (ECLSS) design is critical for human 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 reuse of onboard atmosphere components is required. Current systems utilize space vacuum to fully regenerate adsorbent beds, but this is not sustainable thus necessitating a closed-loop system. 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 for use in future systems.

Cmarik, Gregory E.↗

(Preliminary) Effects of Ball Milling Zeolite Powders for Use in Additively Manufactured Solid Sorbents

Zeolite 13X is favorable to be used as an adsorbent in carbon dioxide (CO2) removal from the spacecraft cabin air. Reducing the size of the zeolite particles and particle size distribution is thought to increase the capacity of CO2 adsorption of the zeolite 13X powder, and potentially increase its manufacturability as a paste for additive manufacturing or slip casting. This paper will go into detail on the process of using ball milling in order to reduce particle size and particle size distribution of commercial zeolite 13X powder, as well as to characterize CO2 adsorption and manufacturability of the milled powder. Both dry and wet ball milling was analyzed during the experiment. Studies were also ran on the amount of time the powder was milled, rotational speed of the milling machine, ball to powder ratio, ball to jar ratio, and ethanol to powder ratio. The processed powder was then characterized through laser diffraction, SEM, and surface measurement techniques to show that particle size and particle size distribution could be reduced, and to show the effect of the reduced particle size and particle size distribution on CO2 adsorption and manufacturability.

zeolite↗

Improving Multifunctional Sorbent Technology for Carbon Dioxide Adsorption

The MultiSORB system aims to improve life support on the ISS and other craft such as the Orion capsule via new technologies that enable more efficient CO2 adsorption. This means that life support systems can function with less power and greater reliability while still processing nominal quantities of CO2. The technologies explored in this poster include the use of zeolite paste in the creation of novel geometries, along with the use of state of the art heating/cooling systems such as titanium heat pipes.

MultiSORB↗

CACTUS: CO 2 Aerogel Capture Towards Utilization and Sequestration

The CACTUS project aimed to develop a novel solid sorbent and sorption module prototype for direct air capture (DAC) of carbon dioxide, by a moisture-swing adsorption (MSA) mechanism. Because MSA uses changes in humidity, not temperature to switch the sorbent from capturing CO 2 to releasing concentrated CO 2 it is > 4X more energy-efficient than the thermal swing process. The goal was to develop a sorbent with a CO 2 capture capacity of 1 mmol CO 2 /g sorbent (or 0.75 mmol CO 2 /g structured sorbent), at a projected scaled cost of < $\$$15/kg sorbent and demonstration of a path to < $\$$100/ton CO 2 . At the end of the project, we achieved 0.8 mmol CO 2 /g sorbent powders, 0.37 mmol CO 2 /g structured sorbent (50% of target), at a projected cost of $\$$29/kg sorbent and an estimated cost of $\$$160/ton CO 2 . The key innovation was SRI’s patented polymer aerogel synthesis platform, which was adapted to produce a nanoporous aerogel with a high density of CO 2 -adsorbing quaternary ammonium groups. This research discovered a new ammonium polymer sorbent and identified a chemical path for its fabrication. The new process solved the monomer immiscibility challenge encountered with the initial method (ammonium is hydrophilic and the crosslinker is hydrophobic). The team fabricated structured sorbent sheets consisting of a non-woven porous substrate impregnated with ammonium polymer and demonstrated its operation in custom made breakthrough test setup MSA DAC built at SRI, and which operates similarly to the envisioned large-scale CO 2 capture plant, to provide data for techno-economic analysis (TEA). TEA sensitivity analysis indicated that ∼$\$$100/ton CO 2 can be achieved if the target capacity of 0.75 mmol CO 2 /g structured sorbent is met. Also identified routes to decrease sorbent manufacturing cost to ∼$\$$19/kg by reducing amounts and recycling the organic solvents. More work is needed on transitioning process manufacturing from powders (which showed a capacity of up to 0.8 mmol/g sorbent) to structured sheets which showed a capacity of 0.37 mmol CO 2 /g structured sorbent (or 0.44 mmol/g sorbent if one excludes the inert porous substrate). This is likely due to different micro/nano-structure of the sorbent and material processing constraints at the laboratory scale. Sorbent cycling studies (> 100 cycles) are needed to investigate its performance stability over time.

99 GENERAL AND MISCELLANEOUS↗

Direct Air Capture Using Trapped Small Amines in Hierarchical Nanoporous Capsules on Porous Electrospun Fibers (Final Technical Report)

This report summarizes the carbon capture research and development conducted by The State University of New York at Buffalo (UB) and GTI Energy (GTI) for award “DE-FE0031969: Direct Air Capture Using Trapped Small Amines in Hierarchical Nanoporous Capsules on Porous Electrospun Fibers” sponsored by the U.S. Department of Energy (DOE). The objective of this project is to develop an innovative sorbent structure of trapped small amines in HNC embedded in PEF for DAC. This involves tailoring both sorbent and PEF materials to achieve a compact system for DAC with high capacity for CO 2 at concentrations typically available in air and at near ambient conditions. An innovative sorbent structure of trapped small amines in hierarchical nanoporous capsules (HNC) embedded in porous electrospun fibers (PEF) was developed for direct air capture (DAC). This involves tailoring both sorbent and PEF materials to achieve a compact system for DAC with high capacity for CO 2 at concentrations typically available in air and at near ambient conditions. An interfacial polymerization process was developed, which utilized loaded amines inside mesoporous silica and trimesoyl chloride (TMC) dissolved in organic solvents as the precursors, to generate a polyamide (PA) coating layer on mesoporous silica and thus trap amines. Reaction conditions, including TMC concentration, organic solvents, reaction time, etc., for interfacial polymerization were optimized to effectively trap loaded amines, and cyclic heating-cooling operation was conducted to evaluate the coating quality. Larger pore volume mesoporous silica was also synthesized to increase amine loading and thus increase CO 2 capacity. The optimized sorbent material exhibited CO 2 capacity as high as 4.88 mmol/g under humid DAC conditions and negligible loss (<1%) during 10 cyclic heating-cooling operations. The optimized PA-coated sorbent also showed fast adsorption and desorption kinetics, with <20% t1/2 increase compared to uncoated sorbent. PEF fabrication conditions, including organic solvents for dissolving core and shell polymers, voltage, distance from the nozzle to the collection panel, etc. were adjusted to better incorporate HNC. After incorporating the optimized sorbent material into PEF, the structured sorbent had a CO 2 capacity of approximately 4.0 mmol/g under humid DAC conditions, with capacity loss of 0.17% per cycle and t1/2 increase less than 10%. A techno-economic analysis (TEA) for the process design for a DAC system based on our developed sorbent structure of trapped small amines in HNC embedded in PEF was conducted. The process design included process description and major equipment sizing and energy and mass balances in addition to scale-up research results and estimated capture cost. Aspen Adsorption Simulator was used to fit the experimentally measured breakthrough curves and extract equilibrium and kinetic data of the optimized sorbent. Our results indicated that for a DAC plant with CO 2 productivity of 3,000 tonne/year, the levelized cost of CO 2 capture was $\$$612/tonne, with the largest contribution of 44.33% from the fixed operation cost. Increasing CO 2 productivity, while maintaining similar fixed operation cost, is expected to significantly reduce the CO 2 capture cost. A sensitivity study was also conducted to understand the influence of total plant cost, sorbent cost, CO 2 concentration in the feed, sorbent mat lifetime, sorbent regeneration electricity, and adsorption blower pressure drop on the levelized cost of CO 2 capture, revealing a capture cost range of $\$$520-870/tonne.

36 MATERIALS SCIENCE↗

Multicomponent gas sorption Joule-Thomson refrigeration

The present invention relates to a cryogenic Joule-Thomson refrigeration capable of pumping multicomponent gases with a single stage sorption compressor system. Alternative methods of pumping a multicomponent gas with a single stage compressor are disclosed. In a first embodiment, the sorbent geometry is such that a void is defined near the output of the sorption compressor. When the sorbent is cooled, the sorbent primarily adsorbs the higher boiling point gas such that the lower boiling point gas passes through the sorbent to occupy the void. When the sorbent is heated, the higher boiling point gas is desorbed at high temperature and pressure and thereafter propels the lower boiling point gas out of the sorption compressor. A mixing chamber is provided to remix the constituent gases prior to expansion of the gas through a Joule-Thomson valve. Other methods of pumping a multicomponent gas are disclosed. For example, where the sorbent is porous and the low boiling point gas does not adsorb very well, the pores of the sorbent will act as a void space for the lower boiling point gas. Alternatively, a mixed sorbent may be used where a first sorbent component physically adsorbs the high boiling point gas and where the second sorbent component chemically absorbs the low boiling point gas.

Jones, Jack A.↗

Evaluation of Technologies to Mitigate the Presence of Gaseous Elemental Mercury in Waste Disposal Containers

A study was conducted to evaluate sorbent technologies that can mitigate the presence of elemental mercury (Hg⁰) in waste containers for mercury-contaminated debris (MCD). Decontamination and demolition (D&D) activities at the Y-12 National Security Complex (Y-12) and other U.S. Department of Energy (DOE) Oak Ridge Reservation (ORR) facilities generate MCD requiring offsite disposal. The debris is packaged in appropriate waste containers and may be temporarily stored onsite prior to transport for treatment and/or disposal. During transportation of loads that had no visible liquid Hg at the point of origin, temperature changes can cause Hg⁰ to evaporate, condense, and form droplets on container walls. Furthermore, vibration during transportation could cause beads of Hg to be released from the debris, container walls, and ceiling, resulting in pools of liquid Hg⁰ on the container floor. Waste acceptance criteria (WAC) limitations for commercial disposal facilities, the Nevada National Security Site (NNSS), and ORR mixed low-level waste landfills prohibit the presence of any free liquids in containers identified as a solid waste form. Potential solutions to mitigate the presence of residual liquids that could be formed through vapor condensation include the use of sorbents or similar materials to capture and stabilize volatile Hg⁰ vapors and thus ensure compliance with landfill WAC requirements. This report summarizes data from small-scale laboratory experiments conducted to evaluate sorbent materials for Hg⁰ vapor suppression and sorption of liquid Hg⁰ that could form under relevant transportation and disposal conditions. A series of experiments was conducted to evaluate commercial sorbent materials and their effectiveness for Hg⁰ sorption across a temperature range from 19.4°C to 60°C. The impact of residual moisture on sorption was investigated under relevant conditions, and leaching tests were performed to assess the stability of Hg⁰ captured sorbent materials. The results provide estimates for sorbent quantities needed for a given Hg⁰ mass loading based on experimental results exposing sorbents to gaseous and liquid Hg⁰ at various mass ratios. Overall, sorbents that were most effective for Hg⁰ vapor suppression were brominated activated carbons, mackinawite-based sorbents coated on vermiculite, and sulfur-modified granular activated carbon. Elevated temperatures and moisture conditions did not result in significant increases of Hg⁰ headspace concentrations, and the materials also demonstrated high sorption capacities for the sorption of liquid Hg⁰.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

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↗

Reversible Ammonia Sorption for the Primary Life Support System (PLSS)

Results are presented on the development of regenerable trace-contaminant (TC) sorbent for use in Extravehicular Activities (EVAs), and more specifically in the Primary Life Support System (PLSS). Since ammonia is the most important TC to be captured, data presented in this paper are limited to ammonia sorption, with results relevant to other TCs to be reported at a later time. The currently available TC-control technology involves the use of a packed bed of acid-impregnated granular charcoal. The sorbent is non-regenerable, and its use is associated with appreciable pressure drop, i.e. power consumption. The objective of this work is to demonstrate the feasibility of using vacuum-regenerable sorbents for PLSS application. In this study, several carbon sorbent monoliths were fabricated and tested. Multiple adsorption/vacuum-regeneration cycles were demonstrated at room temperature, as well as carbon surface conditioning that enhances ammonia sorption without impairing sorbent regeneration. Depending on sorbent monolith geometry, the reduction in pressure drop with respect to granular sorbent was found to be between 50% and two orders of magnitude. Resistive heating of the carbon sorbent monolith was demonstrated by applying voltage to the opposite ends of the monolith.

Wojtowicz, Marek A.↗

Abstract for CRADA between NETL and the AZ Board of Regents on behalf of Arizona State University

Arizona State University (ASU) and the National Energy Technology Laboratory (NETL) will collaborate on the development and scale up of sorbent composites that efficiently capture carbon dioxide (CO 2 ) directly from air under an awarded project from the Department of Energy’s Direct Air Capture (DAC) Pre-Commercialization Technology Prize. For DAC to be considered a viable technology for decarbonization, the cost of carbon removal needs to decrease below the proposed carbon tax incentive outlined in the recent Inflation Reduction Act (IRA) (Section 45 Q), which is set at $\$$180 per ton of CO 2 . Achieving this goal requires the development of a cost-effective, environmentally friendly sorbent with high CO 2 sorption capacity and efficient kinetics under DAC conditions as the overall cost of CO 2 captured is highly sensitive to factors such as sorbent cost and sorbent lifetime. ASU has developed a sorbent technology that can potentially reduce CO 2 removal costs by DAC. NETL has expertise in DAC TEA and LCA development and DAC sorbent testing. The collaboration between ASU and NETL aims to accelerate development and deployment of ASU’s technology by quantifying the performance, cost and lifecycle impacts of ASU’s technology and validating sorbent performance.

54 ENVIRONMENTAL SCIENCES↗