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Results for “Catalytic Oxidizer”

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 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1992

Catalytic oxidation for treatment of ECLSS and PMMS waste streams

Catalytic oxidation was added to the baseline multifiltration technology for use on the Space Station Freedom in order to convert low-molecular weight organic waste components such as alcohols, aldehydes, ketones, amides, and thiocarbamides to CO2 at low temperature (121 C), thereby reducing the total organic carbon (TOC) to below 500 ppb. The rate of reaction for the catalytic oxidation of aqueous organics to CO2 and water depends primarily upon the catalyst, temperature, and concentration of reactants. This paper describes a kinetic study conducted to determine the impact of each of these parameters upon the reaction rate. The results indicate that a classic kinetic model, the Langmuir-Hinshelwood rate equation for heterogeneous catalysis, can accurately represent the functional dependencies of this rate.

Akse, James R.↗
NASA NTRSDate not supplied

Development of a Microlith® Catalytic Oxidizer for Exploration Trace Contaminant Control

The state-of-the-art in long mission duration spacecraft trace contaminant control processes rely on high-temperature catalytic oxidation for light contaminant removal. Target compounds for oxidation include metabolic methane, carbon monoxide, and low molecular weight volatile organics such as formaldehyde and methanol. Precision Combustion, Inc. and NASA Marshall Space Flight Center have been developing and testing prototype high temperature catalytic oxidizers based on PCI’s patented Microlith® technology to meet the requirements of future spaceflight exploration missions. To this end, our latest generation Microlith oxidizer, featuring an integrated heat recuperator, was subjected to endurance testing to simulate catalyst ageing over a Mars transit mission duration. Periodic reactor health testing indicates our approach results in a robust contaminant control solution for exploration missions beyond low earth orbit. Based on the demonstrated performance of this unit, a next-generation prototype was designed to meet exploration contaminant load control demands while upgrading the prototype form and fit to match flight-compatible interfaces. Prototype design considerations intended to reduce power consumption, impacting process thermal and hydraulic performance, are discussed herein.

Trace Contaminant Control↗
NASA NTRS1980

Direct /TEM/ observation of the catalytic oxidation of amorphous carbon by Pd particles

The catalytic oxidation of amorphous carbon substrates by Pd particles is observed by in situ transmission electron microscopy. Various modes of selective attack of the carbon substrate in the immediate neighborhood of Pd particles are observed, which can be correlated with different degrees of particle mobility. Using amorphous substrates we have been able to demonstrate that the particle-substrate interaction is influenced by the structure of the particle. This has not previously been noted.

Moorhead, R. D.↗
NASA NTRSDate not supplied

Performance of Flight Compatible Microlith® Catalytic Oxidizer for Exploration Trace Contaminant Control

Precision Combustion, Inc. (PCI) and NASA Marshall Space Flight Center have been developing, characterizing, and optimizing prototype high temperature catalytic oxidizers based on PCI’s patented Microlith® technology and long-term endurance test data to meet the requirements of future spaceflight exploration missions. Based on the demonstrated performance (20,000+ hours) of a subscale prototype, a next-generation prototype was designed to meet exploration contaminant load control demands while upgrading the prototype form and fit to match flight-compatible interfaces. Prototype design considerations intended to minimize power consumption, impacting process thermal and hydraulic performance, are discussed herein. We also report on performance characteristics of the catalytic oxidizer and future efforts for component packaging and light-weighting.

Trace Contaminants↗
NASA NTRS1971

Vacuum distillation: vapor filtered-catalytic oxidation water reclamation system utilizing radioisotopes

The development of a functional model water reclamation system is discussed. The system produces potable water by distillation from the urine and respiration-perspiration condensate at the normal rate generated by four men. Basic processes employed are vacuum distillation, vapor filtration, vapor phase catalytic oxidation, and condensation. The system is designed to use four 75-watt isotope heaters for distillation thermal input, and one 45-watt isotope for the catalytic oxidation unit. The system is capable of collecting and storing urine, and provides for stabilizing the urine by chemical pretreatment. The functional model system is designed for operation in a weightless condition with liquid-vapor phase separators for the evaporator still, and centrifugal separators for urine collection and vapor condensation. The system provides for storing and dispensing reclaimed potable water. The system operates in a batch mode for 40 days, with urine residues accumulating in the evaporator. The evaporator still and residue are removed to storage and replaced with a fresh still for the next 40-day period.

Honegger, R. J.↗
NASA NTRS2004

Electrochemical, H2O2-Boosted Catalytic Oxidation System

An improved water-sterilizing aqueous-phase catalytic oxidation system (APCOS) is based partly on the electrochemical generation of hydrogen peroxide (H2O2). This H2O2-boosted system offers significant improvements over prior dissolved-oxygen water-sterilizing systems in the way in which it increases oxidation capabilities, supplies H2O2 when needed, reduces the total organic carbon (TOC) content of treated water to a low level, consumes less energy than prior systems do, reduces the risk of contamination, and costs less to operate. This system was developed as a variant of part of an improved waste-management subsystem of the life-support system of a spacecraft. Going beyond its original intended purpose, it offers the advantage of being able to produce H2O2 on demand for surface sterilization and/or decontamination: this is a major advantage inasmuch as the benign byproducts of this H2O2 system, unlike those of systems that utilize other chemical sterilants, place no additional burden of containment control on other spacecraft air- or water-reclamation systems.

Akse, James R.↗
NASA NTRS1987

Rare isotope studies involving catalytic oxidation of CO over platinum-tin oxide

Results of studies utilizing normal and rare oxygen isotopes in the catalytic oxidation of carbon monoxide over a platinum-tin oxide catalyst substrate are presented. Chemisorption of labeled carbon monoxide on the catalyst followed by thermal desorption yielded a carbon dioxide product with an oxygen-18 composition consistent with the formation of a carbonate-like intermediate in the chemisorption process. The efficacy of a method developed for the oxygen-18 labeling of the platinum-tin oxide catalyst surface for use in closed cycle pulsed care isotope carbon dioxide lasers is demonstrated for the equivalent of 10 to the 6th power pulses at 10 pulses per second.

Upchurch, Billy T.↗
NASA NTRS1991

Catalytic oxidation for treatment of ECLSS and PMMS waste streams

It is shown that catalytic oxidation is an effective technique for the removal of trace organic contaminants in a multifiltration potable processor's effluent. Essential elements of this technology are devices that deliver oxygen to the influent, and remove gaseous reaction byproducts from the effluent, via hollow-tube, gas-permeable membranes. Iodine, which poisons existing catalysis, is removed by a small deiodination bed prior to catalytic reactor entrance. The catalyst used is a mixture of Pt and Ru deposited on carbon, operating at 125-160 C and 39-90 psi pressures.

Akse, James R.↗
NASA NTRS1981

Determination of a kinetic region in catalytic oxidation of carbon monoxide

The catalytic activity of cupric oxide activated with ceric oxide in a braod interval of volumetric velocities was investigated. It was determined that for practical catalysts used in the diffuse region, dilution of the active substance by an inert diluent increases the effectiveness of the catalysts.

Sultanov, M. Y.↗
NASA NTRS1974

Catalytic oxidation of trace levels of methane in oxygen in a tubular reactor

An experimental investigation of catalytic oxidation of trace levels of methane in oxygen was conducted in a tubular reactor. Two noble metal solid catalysts were explored: a 1-percent platinum on gamma alumina and a 0.5-percent rhodium on gamma alumina. For each catalyst the activity was determined as a function of temperature, pressure, space velocity, and methane concentration. The rhodium catalyst was considerably more active than the platinum catalyst. For each catalyst mass transfer had a pronounced effect upon activity at low space velocity.

Warshay, M.↗
NASA NTRS1972

Development of a sorber trace contaminant control system including pre- and post-sorbers for a catalytic oxidizer

A general methodology was developed for spacecraft contaminant control system design. Elements considered for contaminant control were catalytic oxidation with isotope or electrical heat and pre- and post-sorbers, charcoal with regeneration and non-regeneration, and reactive constituents. A technique is described for sizing a charcoal bed for a multiple contaminant load.

Olcott, T. M.↗
NASA NTRS2005

Thermal Catalytic Oxidation of Airborne Contaminants by a Reactor Using Ultra-Short Channel Length, Monolithic Catalyst Substrates

Contaminated air, whether in a crewed spacecraft cabin or terrestrial work and living spaces, is a pervasive problem affecting human health, performance, and well being. The need for highly effective, economical air quality processes spans a wide range of terrestrial and space flight applications. Typically, air quality control processes rely on absorption-based processes. Most industrial packed-bed adsorption processes use activated carbon. Once saturated, the carbon is either dumped or regenerated. In either case, the dumped carbon and concentrated waste streams constitute a hazardous waste that must be handled safely while minimizing environmental impact. Thermal catalytic oxidation processes designed to address waste handling issues are moving to the forefront of cleaner air quality control and process gas decontamination processes. Careful consideration in designing the catalyst substrate and reactor can lead to more complete contaminant destruction and poisoning resistance. Maintenance improvements leading to reduced waste handling and process downtime can also be realized. Performance of a prototype thermal catalytic reaction based on ultra-short waste channel, monolith catalyst substrate design, under a variety of process flow and contaminant loading conditions, is discussed.

Perry, J. L.↗
NASA NTRS2007

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↗