Sample records for oxygen-enriched combustion system

  1. Review of Membrane Oxygen Enrichment for Efficient Combustion

    NASA Astrophysics Data System (ADS)

    Ariono, Danu; Kusuma Wardani, Anita

    2017-07-01

    Oxygen enrichment from air is a simple way of increasing the efficiency of combustion process, as in oxy-combustion. Oxy-combustion has become one of the most attracting combustion technologies because of its potential to address both pollutant reduction and CO2 capture. In oxy-combustion, the fuel and recycled flue gas are combusted with oxygen enriched air (OEA). By using OEA, many benefits can be obtained, such as increasing available heat, improving ignition characteristics, flue gas reduction, increasing productivity, energy efficiency, turndown ratio, and flame stability. Membrane-based gas separation for OEA production becomes an attractive technology over the conventional technology due to the some advantages, including low capital cost, low energy consumption, compact size, and modularity. A single pass through membrane usually can enrich O2 concentration in the air up to 35% and a 50% concentration can be achieved with a double pass of membrane. The use of OEA in the combustion process eliminates the presence of nitrogen in the flue gas. Hence, the flue gas is mainly composed of CO2 and condensable water that can be easily separated. This paper gives an overview of oxy-combustion with membrane technology for oxygen enrichment process. Special attention is given to OEA production and the effect of OEA to the efficiency of combustion.

  2. Variable oxygen/nitrogen enriched intake air system for internal combustion engine applications

    DOEpatents

    Poola, Ramesh B.; Sekar, Ramanujam R.; Cole, Roger L.

    1997-01-01

    An air supply control system for selectively supplying ambient air, oxygen enriched air and nitrogen enriched air to an intake of an internal combustion engine includes an air mixing chamber that is in fluid communication with the air intake. At least a portion of the ambient air flowing to the mixing chamber is selectively diverted through a secondary path that includes a selectively permeable air separating membrane device due a differential pressure established across the air separating membrane. The permeable membrane device separates a portion of the nitrogen in the ambient air so that oxygen enriched air (permeate) and nitrogen enriched air (retentate) are produced. The oxygen enriched air and the nitrogen enriched air can be selectively supplied to the mixing chamber or expelled to atmosphere. Alternatively, a portion of the nitrogen enriched air can be supplied through another control valve to a monatomic-nitrogen plasma generator device so that atomic nitrogen produced from the nitrogen enriched air can be then injected into the exhaust of the engine. The oxygen enriched air or the nitrogen enriched air becomes mixed with the ambient air in the mixing chamber and then the mixed air is supplied to the intake of the engine. As a result, the air being supplied to the intake of the engine can be regulated with respect to the concentration of oxygen and/or nitrogen.

  3. Study on Characteristics of Co-firing Ammonia/Methane Fuels under Oxygen Enriched Combustion Conditions

    NASA Astrophysics Data System (ADS)

    Xiao, Hua; Wang, Zhaolin; Valera-Medina, Agustin; Bowen, Philip J.

    2018-06-01

    Having a background of utilising ammonia as an alternative fuel for power generation, exploring the feasibility of co-firing ammonia with methane is proposed to use ammonia to substitute conventional natural gas. However, improvement of the combustion of such fuels can be achieved using conditions that enable an increase of oxygenation, thus fomenting the combustion process of a slower reactive molecule as ammonia. Therefore, the present study looks at oxygen enriched combustion technologies, a proposed concept to improve the performance of ammonia/methane combustion. To investigate the characteristics of ammonia/methane combustion under oxygen enriched conditions, adiabatic burning velocity and burner stabilized laminar flame emissions were studied. Simulation results show that the oxygen enriched method can help to significantly enhance the propagation of ammonia/methane combustion without changing the emission level, which would be quite promising for the design of systems using this fuel for practical applications. Furthermore, to produce low computational-cost flame chemistry for detailed numerical analyses for future combustion studies, three reduced combustion mechanisms of the well-known Konnov's mechanism were compared in ammonia/methane flame simulations under practical gas turbine combustor conditions. Results show that the reduced reaction mechanisms can provide good results for further analyses of oxygen enriched combustion of ammonia/methane. The results obtained in this study also allow gas turbine designers and modellers to choose the most suitable mechanism for further combustion studies and development.

  4. Simulation and experiment for oxygen-enriched combustion engine using liquid oxygen to solidify CO2

    NASA Astrophysics Data System (ADS)

    Liu, Yongfeng; Jia, Xiaoshe; Pei, Pucheng; Lu, Yong; Yi, Li; Shi, Yan

    2016-01-01

    For capturing and recycling of CO2 in the internal combustion engine, Rankle cycle engine can reduce the exhaust pollutants effectively under the condition of ensuring the engine thermal efficiency by using the techniques of spraying water in the cylinder and optimizing the ignition advance angle. However, due to the water spray nozzle need to be installed on the cylinder, which increases the cylinder head design difficulty and makes the combustion conditions become more complicated. In this paper, a new method is presented to carry out the closing inlet and exhaust system for internal combustion engines. The proposed new method uses liquid oxygen to solidify part of cooled CO2 from exhaust system into dry ice and the liquid oxygen turns into gas oxygen which is sent to inlet system. The other part of CO2 is sent to inlet system and mixed with oxygen, which can reduce the oxygen-enriched combustion detonation tendency and make combustion stable. Computing grid of the IP52FMI single-cylinder four-stroke gasoline-engine is established according to the actual shape of the combustion chamber using KIVA-3V program. The effects of exhaust gas recirculation (EGR) rate are analyzed on the temperatures, the pressures and the instantaneous heat release rates when the EGR rate is more than 8%. The possibility of enclosing intake and exhaust system for engine is verified. The carbon dioxide trapping device is designed and the IP52FMI engine is transformed and the CO2 capture experiment is carried out. The experimental results show that when the EGR rate is 36% for the optimum EGR rate. When the liquid oxygen of 35.80-437.40 g is imported into the device and last 1-20 min, respectively, 21.50-701.30 g dry ice is obtained. This research proposes a new design method which can capture CO2 for vehicular internal combustion engine.

  5. Compact Analyzer/Controller For Oxygen-Enrichment System

    NASA Technical Reports Server (NTRS)

    Puster, Richard L.; Singh, Jag J.; Sprinkle, Danny R.

    1990-01-01

    System controls hypersonic air-breathing engine tests. Compact analyzer/controller developed, built, and tested in small-scale wind tunnel prototype of the 8' HTT (High-Temperature Tunnel). Monitors level of oxygen and controls addition of liquid oxygen to enrich atmosphere for combustion. Ensures meaningful ground tests of hypersonic engines in range of speeds from mach 4 to mach 7.

  6. Test Would Quantify Combustion Oxygen From Different Sources

    NASA Technical Reports Server (NTRS)

    Tapphorn, Ralph M.

    1993-01-01

    Proposed isotope-enrichment scheme enables determination of contributions of dual sources of oxygen for combustion. Liquid oxygen or other artificial stream enriched with O(18) to about 1 percent by weight. Combustion products analyzed by mass spectrometer to measure relative abundances of H2O(18) and H2O(16). From relative abundances of water products measured, one computes relative contribution of oxygen extracted from stream compared to other source of oxygen in combustion process. Used to determine contributions of natural oxygen in air and liquid oxygen supplied in separate stream mixed with air or sent directly into combustion chamber.

  7. Low NOx combustion using cogenerated oxygen and nitrogen streams

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kobayashi, Hisashi; Bool, Lawrence E; Snyder, William J

    Combustion of hydrocarbon fuel is achieved with less formation of NOx by feeding the fuel into a slightly oxygen-enriched atmosphere, and separating air into oxygen-rich and nitrogen-rich streams which are fed separately into the combustion device.

  8. MHD performance calculations with oxygen enrichment

    NASA Technical Reports Server (NTRS)

    Pian, C. C. P.; Staiger, P. J.; Seikel, G. R.

    1979-01-01

    The impact of oxygen enrichment of the combustion air on the generator and overall plant performance was studied for the ECAS-scale MHD/steam plants. A channel optimization technique is described and the results of generator performance calculations using this technique are presented. Performance maps were generated to assess the impact of various generator parameters. Directly and separately preheated plant performance with varying O2 enrichment was calculated. The optimal level of enrichment was a function of plant type and preheat temperature. The sensitivity of overall plant performance to critical channel assumptions and oxygen plant performance characteristics was also examined.

  9. Automatic calibration and control system for a combined oxygen and combustibles analyzer

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Woolbert, G.D.; Jewett, S.Y.; Robertson, J.W. Jr.

    1989-08-01

    This patent describes an automatic, periodically calibrating system for continuous output of calibrated signals from a combined oxygen and combustibles analyzer. It comprises: a combined oxygen and combustibles analyzer for sensing a level of oxygen and a level of combustibles in a volatile atmosphere and for producing a first sample signal indicative of the oxygen level and a second sample signal indicative of the combustibles level; means for introducing zero and span calibration test gases into the analyzer; means for periodically calibrating the analyzer. This including: a data control unit; a timer unit; a mechanical unit, means for calculating zeromore » and span values for oxygen and combustibles, means for comparing the calculated zero and span values for oxygen and combustibles to the preset alarm limits for oxygen and combustibles, means for activating an operator alarm, means for calculating oxygen and combustibles drift adjustments, a memory unit; and means for applying the oxygen and combustibles drift adjustments concurrently to the first and second sample signals, according to predetermined mathematical relationship, to obtain calibrated output signals indicative of the oxygen and combustibles level in the volatile atmosphere.« less

  10. Guide for Oxygen Hazards Analyses on Components and Systems

    NASA Technical Reports Server (NTRS)

    Stoltzfus, Joel M.; Dees, Jesse; Poe, Robert F.

    1996-01-01

    Because most materials, including metals, will burn in an oxygen-enriched environment, hazards are always present when using oxygen. Most materials will ignite at lower temperatures in an oxygen-enriched environment than in air, and once ignited, combustion rates are greater in the oxygen-enriched environment. Many metals burn violently in an oxygen-enriched environment when ignited. Lubricants, tapes, gaskets, fuels, and solvents can increase the possibility of ignition in oxygen systems. However, these hazards do not preclude the use of oxygen. Oxygen may be safely used if all the materials in a system are not flammable in the end-use environment or if ignition sources are identified and controlled. These ignition and combustion hazards necessitate a proper oxygen hazards analysis before introducing a material or component into oxygen service. The objective of this test plan is to describe the White Sands Test Facility oxygen hazards analysis to be performed on components and systems before oxygen is introduced and is recommended before implementing the oxygen component qualification procedure. The plan describes the NASA Johnson Space Center White Sands Test Facility method consistent with the ASTM documents for analyzing the hazards of components and systems exposed to an oxygen-enriched environment. The oxygen hazards analysis is a useful tool for oxygen-system designers, system engineers, and facility managers. Problem areas can be pinpointed before oxygen is introduced into the system, preventing damage to hardware and possible injury or loss of life.

  11. Carbon dioxide remediation via oxygen-enriched combustion using dense ceramic membranes

    DOEpatents

    Balachandran, Uthamalingam; Bose, Arun C.; McIlvried, Howard G.

    2001-01-01

    A method of combusting pulverized coal by mixing the pulverized coal and an oxidant gas to provide a pulverized coal-oxidant gas mixture and contacting the pulverized coal-oxidant gas mixture with a flame sufficiently hot to combust the mixture. An oxygen-containing gas is passed in contact with a dense ceramic membrane of metal oxide material having electron conductivity and oxygen ion conductivity that is gas-impervious until the oxygen concentration on one side of the membrane is not less than about 30% by volume. An oxidant gas with an oxygen concentration of not less than about 30% by volume and a CO.sub.2 concentration of not less than about 30% by volume and pulverized coal is contacted with a flame sufficiently hot to combust the mixture to produce heat and a flue gas. One dense ceramic membrane disclosed is selected from the group consisting of materials having formulae SrCo.sub.0.8 Fe.sub.0.2 O.sub.x, SrCo.sub.0.5 FeO.sub.x and La.sub.0.2 Sr.sub.0.8 Co.sub.0.4 Fe.sub.0.6 O.sub.x.

  12. MSW oxy-enriched incineration technology applied in China: combustion temperature, flue gas loss and economic considerations.

    PubMed

    Fu, Zhe; Zhang, Shihong; Li, Xiangpeng; Shao, Jingai; Wang, Ke; Chen, Hanping

    2015-04-01

    To investigate the application prospect of MSW oxy-enriched incineration technology in China, the technical and economical analyses of a municipal solid waste (MSW) grate furnace with oxy-fuel incineration technology in comparison to co-incineration with coal are performed. The rated capacity of the grate furnace is 350 tonnes MSW per day. When raw MSW is burned, the amount of pure oxygen injected should be about 14.5 wt.% under 25% O2 oxy-fuel combustion conditions with the mode of oxygen supply determined by the actual situation. According to the isothermal combustion temperature (Ta), the combustion effect of 25% O2 oxy-enriched incineration (α = 1.43) is identical with that of MSW co-incineration with 20% mass ratio of coal (α = 1.91). However, the former is better than the latter in terms of plant cost, flue gas loss, and environmental impact. Despite the lower costs of MSW co-incineration with mass ratio of 5% and 10% coal (α = 1.91), 25% O2 oxy-enriched incineration (α = 1.43) is far more advantageous in combustion and pollutant control. Conventional combustion flue gas loss (q2) for co-incineration with 0% coal, 20% coal, 10% coal, 5% coal are around 17%, 13%, 14% and 15%, respectively, while that under the condition of 25% O2 oxy-enriched combustion is approximately 12% (α = 1.43). Clearly, q2 of oxy-enriched incineration is less than other methods under the same combustion conditions. High moisture content presents challenges for MSW incineration, therefore it is necessary to dry MSW prior to incineration, and making oxy-enriched incineration technology achieves higher combustion temperature and lower flue gas loss. In conclusion, based on technical and economical analysis, MSW oxy-enriched incineration retains obvious advantages and demonstrates great future prospects for MSW incineration in China. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. A Brief Study on Toxic Combustion Products of the Polymers Used in High-Pressure Oxygen Systems

    NASA Technical Reports Server (NTRS)

    Hshieh, Fu-Yu; Beeson, Harold D.

    2005-01-01

    One likely cause of polymer ignition in a high-pressure oxygen system is the adiabatic-compression heating of polymers caused by pneumatic impact. Oxidative pyrolysis or combustion of polymers in a high-pressure oxygen system could generate toxic gases. This paper investigates the feasibility of using the NASA pneumatic-impact system to conduct adiabatic-compression combustion tests and determines the toxic combustion products produced from the burning of five selected polymers. Five polymers commonly used in high-pressure oxygen systems, Zytel(Registered TradeMark) 42 (Nylon 6/6), Buna N (nitrile rubber), Witon(Registered TradeMark) A (copolymer of vinylidene fluoride and hexafluoropropylene), Neoflon(Registered TradeMark) (polychlorotrifluoroethylene), and Teflon(Registered TradeMark) (polytetrafluoroethylene), were tested in the NASA pneumatic-impact test system at 17.2-MPa oxygen pressure. The polymers were ignited and burned; combustion products were collected in a stainless-steel sample bottle and analyzed using various methods. The results show that the NASA pneumatic-impact system is an appropriate test system to conduct adiabatic-compression combustion tests and to collect combustion products for further chemical analysis. The composition of the combustion product gas generated from burning the five selected polymers are presented and discussed.

  14. A Preliminary Study on the Toxic Combustion Products Testing of Polymers Used in High-Pressure Oxygen Systems

    NASA Technical Reports Server (NTRS)

    Hshieh, Fu-Yu; Beeson, Harold D.

    2004-01-01

    One likely cause of polymer ignition in a high-pressure oxygen system is adiabatic-compression heating of polymers caused by pneumatic impact. Oxidative _ pyrolysis or combustion of polymers in a high-pressure oxygen system could generate toxic gases. This paper reports the preliminary results of toxic combustion product testing of selected polymers in a pneumatic-impact test system. Five polymers commonly used in high-pressure oxygen systems, Nylon 6/6, polychlorotrifluoroethylene (CTFE), polytetrafluoroethylene (PTFE), fluoroelastomer (Viton(TradeMark) A), and nitrile rubber (Buna N), were tested in a pneumatic-impact test system at 2500- or 3500-psia oxygen pressure. The polymers were ignited and burned, then combustion products were collected in a stainless-steel sample bottle and analyzed by GC/MS/IRD, GC/FID, and GC/Methanizer/FID. The results of adiabatic-compression tests show that combustion of hydrocarbon polymers, nitrogen-containing polymers, and halogenated polymers in high-pressure oxygen systems are relatively complete. Toxicity of the combustion product gas is presumably much lower than the combustion product gas generated from ambient-pressure oxygen (or air) environments. The NASA-Lewis equilibrium code was used to determine the composition of combustion product gas generated from a simulated, adiabatic-compression test of nine polymers. The results are presented and discussed.

  15. Multi-stage combustion using nitrogen-enriched air

    DOEpatents

    Fischer, Larry E.; Anderson, Brian L.

    2004-09-14

    Multi-stage combustion technology combined with nitrogen-enriched air technology for controlling the combustion temperature and products to extend the maintenance and lifetime cycles of materials in contact with combustion products and to reduce pollutants while maintaining relatively high combustion and thermal cycle efficiencies. The first stage of combustion operates fuel rich where most of the heat of combustion is released by burning it with nitrogen-enriched air. Part of the energy in the combustion gases is used to perform work or to provide heat. The cooled combustion gases are reheated by additional stages of combustion until the last stage is at or near stoichiometric conditions. Additional energy is extracted from each stage to result in relatively high thermal cycle efficiency. The air is enriched with nitrogen using air separation technologies such as diffusion, permeable membrane, absorption, and cryogenics. The combustion method is applicable to many types of combustion equipment, including: boilers, burners, turbines, internal combustion engines, and many types of fuel including hydrogen and carbon-based fuels including methane and coal.

  16. Long term analysis of the biomass content in the feed of a waste-to-energy plant with oxygen-enriched combustion air.

    PubMed

    Fellner, Johann; Cencic, Oliver; Zellinger, Günter; Rechberger, Helmut

    2011-10-01

    Thermal utilization of municipal solid waste and commercial wastes has become of increasing importance in European waste management. As waste materials are generally composed of fossil and biogenic materials, a part of the energy generated can be considered as renewable and is thus subsidized in some European countries. Analogously, CO(2) emissions of waste incinerators are only partly accounted for in greenhouse gas inventories. A novel approach for determining these fractions is the so-called balance method. In the present study, the implementation of the balance method on a waste-to-energy plant using oxygen-enriched combustion air was investigated. The findings of the 4-year application indicate on the one hand the general applicability and robustness of the method, and on the other hand the importance of reliable monitoring data. In particular, measured volume flows of the flue gas and the oxygen-enriched combustion air as well as corresponding O(2) and CO(2) contents should regularly be validated. The fraction of renewable (biogenic) energy generated throughout the investigated period amounted to between 27 and 66% for weekly averages, thereby denoting the variation in waste composition over time. The average emission factor of the plant was approximately 45 g CO(2) MJ(-1) energy input or 450 g CO(2) kg(-1) waste incinerated. The maximum error of the final result was about 16% (relative error), which was well above the error (<8%) of the balance method for plants with conventional oxygen supply.

  17. Sooting Limits Of Diffusion Flames With Oxygen-Enriched Air And Diluted Fuel

    NASA Technical Reports Server (NTRS)

    Sunderland, P. B.; Urban, D. L.; Stocker, D. P.; Chao, B. H.; Axelbaum, R. L.

    2003-01-01

    Oxygen-enhanced combustion permits certain benefits and flexibility that are not otherwise available in the design of practical combustors, as discussed by Baukal. The cost of pure and enriched oxygen has declined to the point that oxygen-enhanced combustion is preferable to combustion in air for many applications. Carbon sequestration is greatly facilitated by oxygen enrichment because nitrogen can be eliminated from the product stream. For example, when natural gas (or natural gas diluted with CO2) is burned in pure oxygen, the only significant products are water and CO2. Oxygen-enhanced combustion also has important implications for soot formation, as explored in this work. We propose that soot inception in nonpremixed flames requires a region where C/O ratio, temperature, and residence time are above certain critical values. Soot does not form at low temperatures, with the threshold in nonpremixed flames ranging from about 1250-1650 K, a temperature referred to here as the critical temperature for soot inception, Tc. Soot inception also can be suppressed when residence time is short (equivalently, when the strain rate in counterflow flames is high). Soot induction times of 0.8-15 ms were reported by Tesner and Shurupov for acetylene/nitrogen mixtures at 1473 K. Burner stabilized spherical microgravity flames are employed in this work for two main reasons. First, this configuration offers unrestricted control over convection direction. Second, in steady state these flames are strain-free and thus can yield intrinsic sooting limits in diffusion flames, similar to the way past work in premixed flames has provided intrinsic values of C/O ratio associated with soot inception limits.

  18. Diesel engine experiments with oxygen enrichment, water addition and lower-grade fuel

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Sekar, R.R.; Marr, W.W.; Cole, R.L.

    1990-01-01

    The concept of oxygen enriched air applied to reciprocating engines is getting renewed attention in the context of the progress made in the enrichment methods and the tougher emissions regulations imposed on diesel and gasoline engines. An experimental project was completed in which a direct injection diesel engine was tested with intake oxygen levels of 21% -- 35%. Since an earlier study indicated that it is necessary to use a cheaper fuel to make the concept economically attractive, a less refined fuel was included in the test series. Since a major objection to the use of oxygen enriched combustion airmore » had been the increase in NO{sub x} emissions, a method must be found to reduce NO{sub x}. Introduction of water into the engine combustion process was included in the tests for this purpose. Fuel emulsification with water was the means used here even though other methods could also be used. The teat data indicated a large increase in engine power density, slight improvement in thermal efficiency, significant reductions in smoke and particulate emissions and NO{sub x} emissions controllable with the addition of water. 15 refs., 10 figs., 2 tabs.« less

  19. Oxygen-enriched air for MHD power plants

    NASA Technical Reports Server (NTRS)

    Ebeling, R. W., Jr.; Cutting, J. C.; Burkhart, J. A.

    1979-01-01

    Cryogenic air-separation process cycle variations and compression schemes are examined. They are designed to minimize net system power required to supply pressurized, oxygen-enriched air to the combustor of an MHD power plant with a coal input of 2000 MWt. Power requirements and capital costs for oxygen production and enriched air compression for enrichment levels from 13 to 50% are determined. The results are presented as curves from which total compression power requirements can be estimated for any desired enrichment level at any delivery pressure. It is found that oxygen enrichment and recuperative heating of MHD combustor air to 1400 F yields near-term power plant efficiencies in excess of 45%. A minimum power compression system requires 167 MW to supply 330 lb of oxygen per second and costs roughly 100 million dollars. Preliminary studies show MHD/steam power plants to be competitive with plants using high-temperature air preheaters burning gas.

  20. The effect of oxygen enrichment on soot formation and thermal radiation in turbulent, non-premixed methane flames

    DOE PAGES

    Shaddix, Christopher R.; Williams, Timothy C.

    2016-07-12

    Non-premixed oxy-fuel combustion of natural gas is used in industrial applications where high-intensity heat is required, such as glass manufacturing and metal forging and shaping. In these applications, the high flame temperatures achieved by oxy-fuel combustion increase radiative heat transfer to the surfaces of interest and soot formation within the flame is desired for further augmentation of radiation. However, the high cost of cryogenic air separation has limited the penetration of oxy-fuel combustion technologies. New approaches to air separation are being developed that may reduce oxygen production costs, but only for intermediate levels of oxygen enrichment of air. To determinemore » the influence of oxygen enrichment on soot formation and radiation, we developed a non-premixed coannular burner in which oxygen concentrations and oxidizer flow rates can be independently varied, to distinguish the effects of turbulent mixing intensity from oxygen enrichment on soot formation and flame radiation. Local radiation intensities, soot concentrations, and soot temperatures have been measured using a thin-film thermopile, planar laser-induced incandescence (LII), and two-color imaging pyrometry, respectively. The measurements show that soot formation increases as the oxygen concentration decreases from 100% to 50%, helping to moderate a decrease in overall flame radiation. An increase in turbulence intensity has a marked effect on flame height, soot formation and thermal radiation, leading to decreases in all of these. The soot temperature decreases with a decrease in the oxygen concentration and increases with an increase in turbulent mixing intensity. Altogether, the results suggest that properly designed oxygen-enriched burners that enhance soot formation for intermediate levels of oxygen purity may be able to achieve thermal radiation intensities as high as 85% of traditional oxy-fuel burners utilizing high-purity oxygen.« less

  1. The effect of oxygen enrichment on soot formation and thermal radiation in turbulent, non-premixed methane flames

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Shaddix, Christopher R.; Williams, Timothy C.

    Non-premixed oxy-fuel combustion of natural gas is used in industrial applications where high-intensity heat is required, such as glass manufacturing and metal forging and shaping. In these applications, the high flame temperatures achieved by oxy-fuel combustion increase radiative heat transfer to the surfaces of interest and soot formation within the flame is desired for further augmentation of radiation. However, the high cost of cryogenic air separation has limited the penetration of oxy-fuel combustion technologies. New approaches to air separation are being developed that may reduce oxygen production costs, but only for intermediate levels of oxygen enrichment of air. To determinemore » the influence of oxygen enrichment on soot formation and radiation, we developed a non-premixed coannular burner in which oxygen concentrations and oxidizer flow rates can be independently varied, to distinguish the effects of turbulent mixing intensity from oxygen enrichment on soot formation and flame radiation. Local radiation intensities, soot concentrations, and soot temperatures have been measured using a thin-film thermopile, planar laser-induced incandescence (LII), and two-color imaging pyrometry, respectively. The measurements show that soot formation increases as the oxygen concentration decreases from 100% to 50%, helping to moderate a decrease in overall flame radiation. An increase in turbulence intensity has a marked effect on flame height, soot formation and thermal radiation, leading to decreases in all of these. The soot temperature decreases with a decrease in the oxygen concentration and increases with an increase in turbulent mixing intensity. Altogether, the results suggest that properly designed oxygen-enriched burners that enhance soot formation for intermediate levels of oxygen purity may be able to achieve thermal radiation intensities as high as 85% of traditional oxy-fuel burners utilizing high-purity oxygen.« less

  2. Nitrogen enriched combustion of a natural gas internal combustion engine to reduce NO.sub.x emissions

    DOEpatents

    Biruduganti, Munidhar S.; Gupta, Sreenath Borra; Sekar, R. Raj; McConnell, Steven S.

    2008-11-25

    A method and system for reducing nitrous oxide emissions from an internal combustion engine. An input gas stream of natural gas includes a nitrogen gas enrichment which reduces nitrous oxide emissions. In addition ignition timing for gas combustion is advanced to improve FCE while maintaining lower nitrous oxide emissions.

  3. Method and apparatus for reducing cold-phase emissions by utilizing oxygen-enriched intake air

    DOEpatents

    Poola, Ramesh B.; Sekar, Ramanujam R.; Stork, Kevin C.

    1997-01-01

    An oxygen-enriched air intake control system for an internal combustion engine includes air directing apparatus to control the air flow into the intake of the engine. During normal operation of the engine, ambient air flowing from an air filter of the engine flows through the air directing apparatus into the intake of the engine. In order to decrease the amount of carbon monoxide (CO) and hydrocarbon (HC) emissions that tend to be produced by the engine during a short period of time after the engine is started, the air directing apparatus diverts for a short period of time following the start up of the engine at least a portion of the ambient air from the air filter through a secondary path. The secondary path includes a selectively permeable membrane through which the diverted portion of the ambient air flows. The selectively permeable membrane separates nitrogen and oxygen from the diverted air so that oxygen enriched air containing from about 23% to 25% oxygen by volume is supplied to the intake of the engine.

  4. FIELD DEMONSTRATION OF THE LINDE OXYGEN COMBUSTION SYSTEM ON THE EPA MOBILE INCINERATOR

    EPA Science Inventory

    This paper summarizes the various system performance tests and the long-term operating experience of the LINDE Oxygen Combustion System installed on the U.S. Environmental Protection Agency's Mobile Incineration System (MIS) when it was in operation at the Denney Farm site in sou...

  5. Combustion Of Porous Graphite Particles In Oxygen Enriched Air

    NASA Technical Reports Server (NTRS)

    Delisle, Andrew J.; Miller, Fletcher J.; Chelliah, Harsha K.

    2003-01-01

    Combustion of solid fuel particles has many important applications, including power generation and space propulsion systems. The current models available for describing the combustion process of these particles, especially porous solid particles, include various simplifying approximations. One of the most limiting approximations is the lumping of the physical properties of the porous fuel with the heterogeneous chemical reaction rate constants [1]. The primary objective of the present work is to develop a rigorous modeling approach that could decouple such physical and chemical effects from the global heterogeneous reaction rates. For the purpose of validating this model, experiments with porous graphite particles of varying sizes and porosity are being performed under normal and micro gravity.

  6. Quantitative measurement of oxygen in microgravity combustion

    NASA Technical Reports Server (NTRS)

    Silver, Joel A.

    1995-01-01

    This research combines two innovations in an experimental system which should result in a new capability for quantitative, nonintrusive measurement of major combustion species. Using a newly available vertical cavity surface-emitting diode laser (VCSEL) and an improved spatial scanning method, we plan to measure the temporal and spatial profiles of the concentrations and temperatures of molecular oxygen in a candle flame and in a solid fuel (cellulose sheet) system. The required sensitivity for detecting oxygen is achieved by the use of high frequency wavelength modulation spectroscopy (WMS). Measurements will be performed in the NASA Lewis 2.2-second Drop Tower Facility. The objective of this research is twofold. First, we want to develop a better understanding of the relative roles of diffusion and reaction of oxygen in microgravity combustion. As the primary oxidizer species, oxygen plays a major role in controlling the observed properties of flames, including flame front speed (in solid or liquid flames), extinguishment characteristics, flame size, and flame temperature. The second objective is to develop better diagnostics based on diode laser absorption which can be of real value in microgravity combustion research. We will also demonstrate diode lasers' potential usefulness for compact, intrinsically-safe monitoring sensors aboard spacecraft. Such sensors could be used to monitor any of the major cabin gases as well as important pollutants.

  7. Hybrid membrane--PSA system for separating oxygen from air

    DOEpatents

    Staiger, Chad L [Albuquerque, NM; Vaughn, Mark R [Albuquerque, NM; Miller, A Keith [Albuquerque, NM; Cornelius, Christopher J [Blackburg, VA

    2011-01-25

    A portable, non-cryogenic, oxygen generation system capable of delivering oxygen gas at purities greater than 98% and flow rates of 15 L/min or more is described. The system consists of two major components. The first component is a high efficiency membrane capable of separating argon and a portion of the nitrogen content from air, yielding an oxygen-enriched permeate flow. This is then fed to the second component, a pressure swing adsorption (PSA) unit utilizing a commercially available, but specifically formulated zeolite compound to remove the remainder of the nitrogen from the flow. The system is a unique gas separation system that can operate at ambient temperatures, for producing high purity oxygen for various applications (medical, refining, chemical production, enhanced combustion, fuel cells, etc . . . ) and represents a significant advance compared to current technologies.

  8. An investigation of co-combustion municipal sewage sludge with biomass in a 20kW BFB combustor under air-fired and oxygen-enriched condition.

    PubMed

    Kumar, Rajesh; Singh, Ravi Inder

    2017-12-01

    The behavior of municipal sewage sludge (MSS) with biomass (Guar stalks (GS), Mustard Husk (MH), Prosopis Juliflora Wood (PJW)) has been investigated in a 20kW bubbling fluidized bed (BFB) combustor under both air-fired (A-F) and oxygen-enriched (O-E) conditions. The work presented is divided into three parts, first part cover the thermogravimetric analysis (TGA), second part cover the experimental investigation of BFB combustor, and third part covers the ash analysis. TGA was performed with a ratio of 50%MSS/50%biomass (GS, MH, PJW) and results show that 50%MSS/50%GS has highest combustion characteristic factor (CCF). The experimental investigation of BFB combustor was performed for two different ratios of MSS/biomass (50%/50% and 25%/75%) and the combustion characteristics of blends were distinctive under both A-F and O-E condition. Despite 50%MSS/50%GS showing the highest combustion performance in TGA analysis, it formed agglomerates during burning in BFB. Due to this formation of large amount of agglomerates, de-fluidization was observed in the combustor bed after 65-75min in A-F conditions. The rate of de-fluidization increased under O-E condition. The de-fluidization problem disappeared when the share of MSS was reduced to 25%, but small amounts of the agglomerate were still present in the bed. With oxygen enhancement, the combustion efficiency of BFB combustor was improved and flue gasses were found within permissible limit. The maximum conceivable combustion efficiency (97.1%) for BFB combustor was accomplished by using 50% MSS/50%PJW under O-E condition. Results show that a ratio of 25%MSS/75%biomass combusted successfully inside the BFB combustor and extensive work is required for efficient utilization of significant share of MSS with biomass. SEM/EDS analyses were performed for agglomerate produced and for the damaged heater to study the surface morphology and compositions. The elemental heterogeneity of fly ash generated during MSS/biomass combustion

  9. Quantitative Measurement of Oxygen in Microgravity Combustion

    NASA Technical Reports Server (NTRS)

    Silver, Joel A.

    1997-01-01

    A low-gravity environment, in space or in ground-based facilities such as drop towers, provides a unique setting for studying combustion mechanisms. Understanding the physical phenomena controlling the ignition and spread of flames in microgravity has importance for space safety as well as for better characterization of dynamical and chemical combustion processes which are normally masked by buoyancy and other gravity-related effects. Due to restrictions associated with performing measurements in reduced gravity, diagnostic methods which have been applied to microgravity combustion studies have generally been limited to capture of flame emissions on film or video, laser Schlieren imaging and (intrusive) temperature measurements using thermocouples. Given the development of detailed theoretical models, more sophisticated diagnostic methods are needed to provide the kind of quantitative data necessary to characterize the properties of microgravity combustion processes as well as provide accurate feedback to improve the predictive capabilities of the models. When the demands of space flight are considered, the need for improved diagnostic systems which are rugged, compact, reliable, and operate at low power becomes apparent. The objective of this research is twofold. First, we want to develop a better understanding of the relative roles of diffusion and reaction of oxygen in microgravity combustion. As the primary oxidizer species, oxygen plays a major role in controlling the observed properties of flames, including flame front speed (in solid or liquid flames), extinguishment characteristics, flame size and flame temperature. The second objective is to develop better diagnostics based on diode laser absorption which can be of real value in both microgravity combustion research and as a sensor on-board Spacelab as either an air quality monitor or as part of a fire detection system. In our prior microgravity work, an eight line-of-sight fiber optic system measured

  10. Oxygen Compatibility of Brass-Filled PTFE Compared to Commonly Used Fluorinated Polymers for Oxygen Systems

    NASA Technical Reports Server (NTRS)

    Herald, Stephen D.; Frisby, Paul M.; Davis, Samuel Eddie

    2009-01-01

    Safe and reliable seal materials for high-pressure oxygen systems sometimes appear to be extinct species when sought out by oxygen systems designers. Materials that seal well are easy to find, but these materials are typically incompatible with oxygen, especially in cryogenic liquid form. This incompatibility can result in seals that leak, or much worse, seals that easily ignite and burn during use. Materials that are compatible with oxygen are easy to find, such as the long list of compatible metals, but these metallic materials are limiting as seal materials. A material that seals well and is oxygen compatible has been the big game in the designer's safari. Scientists at the Materials Combustion Research Facility (MCRF), part of NASA/Marshall Space Flight Center (MSFC), are constantly searching for better materials and processes to improve the safety of oxygen systems. One focus of this effort is improving the characteristics of polymers used in the presence of an oxygen enriched environment. Very few systems can be built which contain no polymeric materials; therefore, materials which have good impact resistance, low heat of combustion, high auto-ignition temperature and that maintain good mechanical properties are essential. The scientists and engineers at the Materials Combustion Research Facility, in cooperation with seal suppliers, are currently testing a new formulation of polytetrafluoroethylene (PTFE) with Brass filler. This Brass-filled PTFE is showing great promise as a seal and seat material for high pressure oxygen systems. Early research has demonstrated very encouraging results, which could rank this material as one of the best fluorinated polymers ever tested. This paper will compare the data obtained for Brass-filled PTFE with other fluorinated polymers, such as TFE-Teflon (PTFE) , Kel-F 81, Viton A, Viton A-500, Fluorel , and Algoflon . A similar metal filled fluorinated polymer, Salox-M , was tested in comparison to Brass-filled PTFE to

  11. Chemical-Looping Combustion and Gasification of Coals and Oxygen Carrier Development: A Brief Review

    DOE PAGES

    Wang, Ping; Means, Nicholas; Shekhawat, Dushyant; ...

    2015-09-24

    Chemical-looping technology is one of the promising CO 2 capture technologies. It generates a CO 2 enriched flue gas, which will greatly benefit CO 2 capture, utilization or sequestration. Both chemical-looping combustion (CLC) and chemical-looping gasification (CLG) have the potential to be used to generate power, chemicals, and liquid fuels. Chemical-looping is an oxygen transporting process using oxygen carriers. Recently, attention has focused on solid fuels such as coal. Coal chemical-looping reactions are more complicated than gaseous fuels due to coal properties (like mineral matter) and the complex reaction pathways involving solid fuels. The mineral matter/ash and sulfur in coalmore » may affect the activity of oxygen carriers. Oxygen carriers are the key issue in chemical-looping processes. Thermogravimetric analysis (TGA) has been widely used for the development of oxygen carriers (e.g., oxide reactivity). Two proposed processes for the CLC of solid fuels are in-situ Gasification Chemical-Looping Combustion (iG-CLC) and Chemical-Looping with Oxygen Uncoupling (CLOU). The objectives of this review are to discuss various chemical-looping processes with coal, summarize TGA applications in oxygen carrier development, and outline the major challenges associated with coal chemical-looping in iG-CLC and CLOU.« less

  12. Fire extinguishing agents for oxygen-enriched atmospheres

    NASA Astrophysics Data System (ADS)

    Plugge, M. A.; Wilson, C. W.; Zallen, D. M.; Walker, J. L.

    1985-12-01

    Fire-suppression agent requirements for extinguishing fires in oxygen-enriched atmospheres were determined employing small-, medium-, large-, and full-scale test apparatuses. The small- and medium-scale tests showed that a doubling of the oxygen concentration required five times more HALON for extinguishment. For fires of similar size and intensity, the effect of oxygen enrichment of the diluent volume in the HC-131A was not as grate as in the smaller compartments of the B-52 which presented a higher damage scenario. The full-scale tests showed that damage to the airframe was as important a factor in extinguishment as oxygen enrichment.

  13. Enhancing SNCR-aided combustion with oxygen addition

    DOEpatents

    Kobayashi, Hisashi; Wu, Kuang Tsai; Bool, III, Lawrence E.

    2004-03-09

    NOx emissions from combustion are reduced, NOx reduction efficiency by SNCR is improved, and other efficiencies are realized, by injecting oxygen into a fuel-rich combustion zone under controlled conditions.

  14. Flammability and sensitivity of materials in oxygen-enriched atmospheres; Proceedings of the Fourth International Symposium, Las Cruces, NM, Apr. 11-13, 1989. Volume 4

    NASA Technical Reports Server (NTRS)

    Stoltzfus, Joel M. (Editor); Benz, Frank J. (Editor); Stradling, Jack S. (Editor)

    1989-01-01

    The present volume discusses the ignition of nonmetallic materials by the impact of high-pressure oxygen, the promoted combustion of nine structural metals in high-pressure gaseous oxygen, the oxygen sensitivity/compatibility ranking of several materials by different test methods, the ignition behavior of silicon greases in oxygen atmospheres, fire spread rates along cylindrical metal rods in high-pressure oxygen, and the design of an ignition-resistant, high pressure/temperature oxygen valve. Also discussed are the promoted ignition of oxygen regulators, the ignition of PTFE-lined flexible hoses by rapid pressurization with oxygen, evolving nonswelling elastomers for high-pressure oxygen environments, the evaluation of systems for oxygen service through the use of the quantitative fault-tree analysis, and oxygen-enriched fires during surgery of the head and neck.

  15. A simplified method for determining heat of combustion of natural gas

    NASA Technical Reports Server (NTRS)

    Singh, Jag J.; Chegini, Hoshang; Mall, Gerald H.

    1987-01-01

    A simplified technique for determination of the heat of combustion of natural gas has been developed. It is a variation of the previously developed technique wherein the carrier air, in which the test sample was burnt, was oxygen enriched to adjust the mole fraction of oxygen in the combustion product gases up to that in the carrier air. The new technique eliminates the need for oxygen enrichment of the experimental mixtures and natural gas samples and has been found to predict their heats of combustion to an uncertainty of the order of 1 percent.

  16. Oxygen enhanced switching to combustion of lower rank fuels

    DOEpatents

    Kobayashi, Hisashi; Bool, III, Lawrence E.; Wu, Kuang Tsai

    2004-03-02

    A furnace that combusts fuel, such as coal, of a given minimum energy content to obtain a stated minimum amount of energy per unit of time is enabled to combust fuel having a lower energy content, while still obtaining at least the stated minimum energy generation rate, by replacing a small amount of the combustion air fed to the furnace by oxygen. The replacement of oxygen for combustion air also provides reduction in the generation of NOx.

  17. Experimental evaluation of oxygen-enriched air and emulsified fuels in a six-cylinder diesel engine

    NASA Astrophysics Data System (ADS)

    Sekar, R. R.; Marr, W. W.; Cole, R. L.; Marciniak, T. J.; Longman, D. E.

    1993-01-01

    The objectives of this investigation are to (1) determine the technical feasibility of using oxygen-enriched air to increase the efficiency of and reduce emissions from diesel engines, (2) examine the effects of water-emulsified fuel on the formation of nitrogen oxides in oxygen-enriched combustion, and (3) investigate the use of lower-grade fuels in high-speed diesel engines by emulsifying the fuel with water. These tests, completed on a Caterpillar model 3406B, six-cylinder engine are a scale-up from previous, single-cylinder-engine tests. The engine was tested with (1) intake-air oxygen levels up to 30%, (2) water content up to 20% of the fuel, (3) three fuel-injection timings, and (4) three fuel-flow rates (power levels). The Taguchi technique for experimental design was used to minimize the number of experimental points in the test matrix. Four separate test matrices were run to cover two different fuel-flow-rate strategies and two different fuels (No. 2 diesel and No. 6 diesel). A liquid-oxygen tank located outside the test cell supplied the oxygen for the tests. The only modification of the engine was installation of a pressure transducer in one cylinder. All tests were run at 1800 rpm, which corresponds to the synchronous speed of a 60-Hz generator. Test results show that oxygen enrichment results in power increases of 50% or more while significantly decreasing the levels of smoke and particulates emitted. The increase in power was accompanied by a small increase in thermal efficiency. Maximum engine power was limited by the test-cell dynamometer capacity and the capacity of the fuel-injection pump. Oxygen enrichment increases nitrogen-oxide emissions significantly. No adverse effects of oxygen enrichment on the turbocharger were observed. The engine operated successfully with No. 6 fuel, but it operated at a lower thermal efficiency and emitted more smoke and particulates than with No. 2 fuel.

  18. Effect of Oxygen Enrichment in Propane Laminar Diffusion Flames under Microgravity and Earth Gravity Conditions

    NASA Astrophysics Data System (ADS)

    Bhatia, Pramod; Singh, Ravinder

    2017-06-01

    Diffusion flames are the most common type of flame which we see in our daily life such as candle flame and match-stick flame. Also, they are the most used flames in practical combustion system such as industrial burner (coal fired, gas fired or oil fired), diesel engines, gas turbines, and solid fuel rockets. In the present study, steady-state global chemistry calculations for 24 different flames were performed using an axisymmetric computational fluid dynamics code (UNICORN). Computation involved simulations of inverse and normal diffusion flames of propane in earth and microgravity condition with varying oxidizer compositions (21, 30, 50, 100 % O2, by mole, in N2). 2 cases were compared with the experimental result for validating the computational model. These flames were stabilized on a 5.5 mm diameter burner with 10 mm of burner length. The effect of oxygen enrichment and variation in gravity (earth gravity and microgravity) on shape and size of diffusion flames, flame temperature, flame velocity have been studied from the computational result obtained. Oxygen enrichment resulted in significant increase in flame temperature for both types of diffusion flames. Also, oxygen enrichment and gravity variation have significant effect on the flame configuration of normal diffusion flames in comparison with inverse diffusion flames. Microgravity normal diffusion flames are spherical in shape and much wider in comparison to earth gravity normal diffusion flames. In inverse diffusion flames, microgravity flames were wider than earth gravity flames. However, microgravity inverse flames were not spherical in shape.

  19. Tri-metallic ferrite oxygen carriers for chemical looping combustion

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Siriwardane, Ranjani V.; Fan, Yueying

    The disclosure provides a tri-metallic ferrite oxygen carrier for the chemical looping combustion of carbonaceous fuels. The tri-metallic ferrite oxygen carrier comprises Cu.sub.xFe.sub.yMn.sub.zO.sub.4-.delta., where Cu.sub.xFe.sub.yMn.sub.zO.sub.4-.delta. is a chemical composition. Generally, 0.5.ltoreq.x.ltoreq.2.0, 0.2.ltoreq.y.ltoreq.2.5, and 0.2.ltoreq.z.ltoreq.2.5, and in some embodiments, 0.8.ltoreq.x.ltoreq.1.2, y.ltoreq.1.2, and z.gtoreq.0.8. The tri-metallic ferrite oxygen carrier may be used in various applications for the combustion of carbonaceous fuels, including as an oxygen carrier for chemical looping combustion.

  20. Sensor for oxygen-combustibles gas mixtures

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Isenberg, A.O.

    1981-08-25

    A molten carbonate electrochemical cell is described which operates at a temperature between 400/sup 0/ and 700/sup 0/ C. It used to remove O/sub 2/ in combination with CO/sub 2/ from an oxygen/combustibles gas mixture to provide a low temperature measurement of the oxygen content of the gas mixture.

  1. Combustion of bulk titanium in oxygen

    NASA Technical Reports Server (NTRS)

    Clark, A. F.; Moulder, J. C.; Runyan, C. C.

    1975-01-01

    The combustion of bulk titanium in one atmosphere oxygen is studied using laser ignition and several analytical techniques. These were high-speed color cinematography, time and space resolved spectra in the visible region, metallography (including SEM) of specimens quenched in argon gas, X-ray and chemical product analyses, and a new optical technique, the Hilbert transform method. The cinematographic application of this technique for visualizing phase objects in the combustion zone is described. The results indicate an initial vapor phase reaction immediately adjacent to the molten surface but as the oxygen uptake progresses the evaporation approaches the point of congruency and a much reduced evaporation rate. This and the accumulation of the various soluble oxides soon drive the reaction zone below the surface where gas formation causes boiling and ejection of particles. The buildup of rutile cuts off the oxygen supply and the reaction ceases.

  2. Polymer-Oxygen Compatibility Testing: Effect of Oxygen Aging on Ignition and Combustion Properties

    NASA Technical Reports Server (NTRS)

    Waller, Jess M.; Haas, Jon P.; Wilson, D. Bruce; Fries, Joseph (Technical Monitor)

    2000-01-01

    The oxygen compatibility of six polymers used in oxygen service was evaluated after exposure for 48 hours to oxygen pressures ranging from 350 to 6200 kPa (50 to 900 psia), and temperatures ranging from 50 to 250 C (122 to 302 F). Three elastomers were tested: CR rubber (C873-70), FKM fluorocarbon rubber (Viton A), and MPQ silicone rubber (MIL-ZZ-765, Class 2); and three thermoplastics were tested: polyhexamethylene adipamide (Zytel 42), polytetrafluoroethylene (Teflon TFE), and polychlorotrifluoroethylene (Neoflon CTFE M400H). Post-aging changes in mass, dimensions, tensile strength, elongation at break, and durometer hardness were determined. Also, the compression set was determined for the three elastomers. Results show that the properties under investigation were more sensitive to oxygen pressure at low to moderate temperatures, and more sensitive to temperature at low to moderate oxygen pressures. Inspection of the results also suggested that both chain scissioning and cross-linking processes were operative, consistent with heterogeneous oxidation. Attempts are underway to verify conclusively the occurrence of heterogeneous oxidation using a simple modulus profiling technique. Finally, the effect of aging at 620 kpa (90 psia) and 121 C (250 F) on ignition and combustion resistance was determined. As expected, aged polymers were less ignitable and combustible (had higher AlTs and lower heats of combustion). Special attention was given to Neoflon CTFE. More specifically, the effect of process history (compression versus extrusion molding) and percent crystallinity (quick- versus slow-quenched) on the AIT, heat of combustion, and impact sensitivity of Neoflon CTFE was investigated. Results show the AIT, heat of combustion, and impact sensitivity to be essentially independent of Neoflon CTFE process history and structure.

  3. Promoted Combustion Test Data Re-Examined

    NASA Technical Reports Server (NTRS)

    Lewis, Michelle; Jeffers, Nathan; Stoltzfus, Joel

    2010-01-01

    Promoted combustion testing of metallic materials has been performed by NASA since the mid-1980s to determine the burn resistance of materials in oxygen-enriched environments. As the technolo gy has advanced, the method of interpreting, presenting, and applying the promoted combustion data has advanced as well. Recently NASA changed the bum criterion from 15 cm (6 in.) to 3 cm (1.2 in.). This new burn criterion was adopted for ASTM G 124, Standard Test Method for Determining the Combustion Behavior- of Metallic Materials in Oxygen-Enriched Atmospheres. Its effect on the test data and the latest method to display the test data will be discussed. Two specific examples that illustrate how this new criterion affects the burn/no-bum thresholds of metal alloys will also be presented.

  4. Oxy Coal Combustion at the US EPA

    EPA Science Inventory

    Oxygen enriched coal (oxy-coal) combustion is a developing, and potentially a strategically key technology intended to accommodate direct CO2 recovery and sequestration. Oxy-coal combustion is also intended for retrofit application to existing power plants. During oxy-coal comb...

  5. Exhaust heated hydrogen and oxygen producing catalytic converter for combustion engine

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Schreiber, E.T.

    1977-07-26

    A steam generator is provided in operative association with a source of water and the exhaust system of a combustion engine including an air induction system provided with primary fuel inlet structure and supplemental fuel inlet structure. The steam generator derives its heat for converting water into steam from the exhaust system of the combustion engine and the steam generator includes a steam outlet communicated with and opening into one end of an elongated tubular housing disposed in good heat transfer relation with the exhaust system of the combustion engine and having a gas outlet at its other end communicatedmore » with the supplemental fuel inlet of the induction system. The tubular housing has iron filings disposed therein and is in such heat transfer relation with the exhaust system of the combustion engine so as to elevate the temperature of steam passing therethrough and to heat the iron filings to the extent that passage of the heated steam over the heated filings will result in hydrogen and oxygen gas being produced in the tubular housing for subsequent passage to the supplemental fuel inlet of the combustion engine induction system.« less

  6. Fire extinguishment in oxygen enriched atmospheres

    NASA Technical Reports Server (NTRS)

    Robertson, A. F.; Rappaport, M. W.

    1973-01-01

    Current state-of-the-art of fire suppression and extinguishment techniques in oxygen enriched atmosphere is reviewed. Four classes of extinguishment action are considered: cooling, separation of reactants, dilution or removal of fuel, and use of chemically reactive agents. Current practice seems to show preference for very fast acting water spray applications to all interior surfaces of earth-based chambers. In space, reliance has been placed on fire prevention methods through the removal of ignition sources and use of nonflammable materials. Recommendations are made for further work related to fire suppression and extinguishment in oxygen enriched atmospheres, and an extensive bibliography is appended.

  7. TECHNOLOGY DEMONSTRATION SUMMARY: THE AMERICAN COMBUSTION PYRETRON THERMAL DESTRUCTION SYSTEM AT THE U.S. EPA'S COMBUSTION FACILITY

    EPA Science Inventory

    The American Combustion Pyretron Thermal Destruction System at the U.S. EPA's Combustion Research Facility. Under the auspices of the Superfund Innovative Technology Evaluation, or SITE, program, a critical assessment was made of the American Combustion Pyretron™ oxygen enha...

  8. Oxygen enrichment and its application to life support systems for workers in high-altitude areas

    PubMed Central

    Li, Yongling; Liu, Yingshu

    2014-01-01

    Background: Workers coming from lowland regions are at risk of developing acute mountain sickness (AMS) when working in low oxygen high-altitude areas. Objectives: The aim of this study was to improve the conditions that lead to hypoxia and ensure the safety of the high-altitude workers. We analyzed the influence of low atmospheric pressure on the oxygen enrichment process in high-altitude areas using an engineering method called low-pressure swing adsorption (LPSA). Methods: Fourteen male subjects were screened and divided into three groups by type of oxygen supply system used: (1) oxygen cylinder group; (2) LPSA oxygen dispersal group; and (3) control group. These tests included arterial oxygen saturation (SaO2), pulse rate (PR), breaths per minute (BPM), and blood pressure (BP). Results: The results showed that after supplying oxygen using the LPSA method at the tunnel face, the SaO2 of workers increased; the incidence of acute mountain sickness, PR, and BPM significantly decreased. Conclusions: The LPSA life support system was found to be a simple, convenient, efficient, reliable, and applicable approach to ensure proper working conditions at construction sites in high-altitude areas. PMID:25000108

  9. Oxygen Transport Membrane Reactors for Oxy-Fuel Combustion and Carbon Capture Purposes

    NASA Astrophysics Data System (ADS)

    Falkenstein-Smith, Ryan L.

    This thesis investigates oxygen transport membrane reactors (OTMs) for the application of oxy-fuel combustion. This is done by evaluating the material properties and oxygen permeability of different OTM compositions subjected to a variety of operating conditions. The scope of this work consists of three components: (1) evaluate the oxygen permeation capabilities of perovskite-type materials for the application of oxy-fuel combustion; (2) determine the effects of dual-phase membrane compositions on the oxygen permeation performance and membrane characteristics; and (3) develop a new method for estimating the oxygen permeation performance of OTMs utilized for the application of oxy-fuel combustion. SrSc0.1Co0.9O3-delta (SSC) is selected as the primary perovskite-type material used in this research due to its reported high ionic and electronic conductive properties and chemical stability. SSC's oxygen ion diffusivity is investigated using a conductivity relaxation technique and thermogravimetric analysis. Material properties such as chemical structure, morphology, and ionic and electronic conductivity are examined by X-ray diffraction (XRD), Scanning Electron Microscope (SEM), and conductivity testing using a four-probe method, respectively. Oxygen permeation tests study the oxygen permeability OTMs under modified membrane temperatures, sweeping gas flow rates, sweeping gas compositions, membrane configurations, and membrane compositions. When utilizing a pure CO2 sweeping gas, the membrane composition was modified with the addition of Sm0.2Ce0.8O1.9-delta (SDC) at varying wt.% to improve the membranes mechanical stability. A newly developed method to evaluate the oxygen permeation performance of OTMs is also presented by fitting OTM's oxygen permeability to the methane fraction in the sweeping gas composition. The fitted data is used to estimate the overall performance and size of OTMs utilized for the application of oxy-fuel combustion. The findings from this

  10. A System for Controlling the Oxygen Content of a Gas Produced by Combustion

    NASA Technical Reports Server (NTRS)

    Singh, J. J.; Davis, W. T.; Puster, R. L. (Inventor)

    1984-01-01

    A mixture of air, CH4 and OH(2) is burned in a combustion chamber to produce a product gas in the test section. The OH(2) content of the product gas is compared with the OH(2) content of reference air in an OH(2) sensor. If there is a difference an error signal is produced at the output of a control circuit which by the means of a solenoid valve, regulates the flow of OH(2) into the combustion chamber to make the error signal zero. The product gas in the test section has the same oxygen content as air.

  11. Combustion and Performance Analyses of Coaxial Element Injectors with Liquid Oxygen/Liquid Methane Propellants

    NASA Technical Reports Server (NTRS)

    Hulka, J. R.; Jones, G. W.

    2010-01-01

    Liquid rocket engines using oxygen and methane propellants are being considered by the National Aeronautics and Space Administration (NASA) for in-space vehicles. This propellant combination has not been previously used in a flight-qualified engine system, so limited test data and analysis results are available at this stage of early development. NASA has funded several hardware-oriented activities with oxygen and methane propellants over the past several years with the Propulsion and Cryogenic Advanced Development (PCAD) project, under the Exploration Technology Development Program. As part of this effort, the NASA Marshall Space Flight Center has conducted combustion, performance, and combustion stability analyses of several of the configurations. This paper summarizes the analyses of combustion and performance as a follow-up to a paper published in the 2008 JANNAF/LPS meeting. Combustion stability analyses are presented in a separate paper. The current paper includes test and analysis results of coaxial element injectors using liquid oxygen and liquid methane or gaseous methane propellants. Several thrust chamber configurations have been modeled, including thrust chambers with multi-element swirl coax element injectors tested at the NASA MSFC, and a uni-element chamber with shear and swirl coax injectors tested at The Pennsylvania State University. Configurations were modeled with two one-dimensional liquid rocket combustion analysis codes, the Rocket Combustor Interaction Design and Analysis (ROCCID), and the Coaxial Injector Combustion Model (CICM). Significant effort was applied to show how these codes can be used to model combustion and performance with oxygen/methane propellants a priori, and what anchoring or calibrating features need to be applied or developed in the future. This paper describes the test hardware configurations, presents the results of all the analyses, and compares the results from the two analytical methods

  12. New method for determining heats of combustion of gaseous hydrocarbons

    NASA Technical Reports Server (NTRS)

    Singh, J. J.; Sprinkle, D. R.; Puster, R. L.

    1985-01-01

    As a spin off of a system developed for monitoring and controlling the oxygen concentration in the Langley 8-foot High Temperature Tunnel, a highly accurate on-line technique was developed for determining heats of combustion of natural gas samples. It is based on measuring the ratio m/n, where m is the (volumetric) flowrate of oxygen required to enrich the carrier air in which the test gas flowing at the rate n is burned, such that the mole fraction of oxygen in the combustion product gases equals that in the carrier air. The m/n ratio is directly related to the heats of combustion of the saturated hydrocarbons present in the natural gas. A measurement of the m/n ratio for the test gas can provide a direct means of determination of its heat of combustion by using the calibration graph relating the m/n values for pure saturated hydrocarbons with their heats of combustion. The accuracy of the technique is determine solely by the accuracy with which the flowrates m and n can be measured and is of the order of 2 percent in the present study. The theoretical principles and experimental results are discussed.

  13. The oxygen isotope enrichment of leaf-exported assimilates--does it always reflect lamina leaf water enrichment?

    PubMed

    Gessler, Arthur; Brandes, Elke; Keitel, Claudia; Boda, Sonja; Kayler, Zachary E; Granier, André; Barbour, Margaret; Farquhar, Graham D; Treydte, Kerstin

    2013-10-01

    The oxygen stable isotope composition of plant organic matter (OM) (particularly of wood and cellulose in the tree ring archive) is valuable in studies of plant-climate interaction, but there is a lack of information on the transfer of the isotope signal from the leaf to heterotrophic tissues. We studied the oxygen isotopic composition and its enrichment above source water of leaf water over diel courses in five tree species covering a broad range of life forms. We tracked the transfer of the isotopic signal to leaf water-soluble OM and further to phloem-transported OM. Observed leaf water evaporative enrichment was consistent with values predicted from mechanistic models taking into account nonsteady-state conditions. While leaf water-soluble OM showed the expected (18)O enrichment in all species, phloem sugars were less enriched than expected from leaf water enrichment in Scots pine (Pinus sylvestris), European larch (Larix decidua) and Alpine ash (Eucalyptus delegatensis). Oxygen atom exchange with nonenriched water during phloem loading and transport, as well as a significant contribution of assimilates from bark photosynthesis, can explain these phloem (18)O enrichment patterns. Our results indicate species-specific uncoupling between the leaf water and the OM oxygen isotope signal, which is important for the interpretation of tree ring data. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

  14. Test methods for determining the suitability of metal alloys for use in oxygen-enriched environments

    NASA Technical Reports Server (NTRS)

    Stoltzfus, Joel M.; Gunaji, Mohan V.

    1991-01-01

    Materials are more flammable in oxygen rich environments than in air. When the structural elements of a system containing oxygen ignite and burn, the results are often catastrophic, causing loss of equipment and perhaps even human lives. Therefore, selection of the proper metallic and non-metallic materials for use in oxygen systems is extremely important. While test methods for the selection of non-metallic materials have been available for years, test methods for the selection of alloys have not been available until recently. Presented here are several test methods that were developed recently at NASA's White Sands Test Facility (WSTF) to study the ignition and combustion of alloys, including the supersonic and subsonic speed particle impact tests, the frictional heating and coefficient of friction tests, and the promoted combustion test. These test methods are available for commercial use.

  15. Fate of hazardous air pollutants in oxygen-fired coal combustion with different flue gas recycling.

    PubMed

    Zhuang, Ye; Pavlish, John H

    2012-04-17

    Experiments were performed to characterize transformation and speciation of hazardous air pollutants (HAPs), including SO(2)/SO(3), NO(x), HCl, particulate matter, mercury, and other trace elements in oxygen-firing bituminous coal with recirculation flue gas (RFG) from 1) an electrostatic precipitator outlet or 2) a wet scrubber outlet. The experimental results showed that oxycombustion with RFG generated a flue gas with less volume and containing HAPs at higher levels, while the actual emissions of HAPs per unit of energy produced were much less than that of air-blown combustion. NO(x) reduction was achieved in oxycombustion because of the elimination of nitrogen and the destruction of NO in the RFG. The elevated SO(2)/SO(3) in flue gas improved sulfur self-retention. SO(3) vapor could reach its dew point in the flue gas with high moisture, which limits the amount of SO(3) vapor in flue gas and possibly induces material corrosion. Most nonvolatile trace elements were less enriched in fly ash in oxycombustion than air-firing because of lower oxycombustion temperatures occurring in the present study. Meanwhile, Hg and Se were found to be enriched on submicrometer fly ash at higher levels in oxy-firing than in air-blown combustion.

  16. DEMONSTRATION BULLETIN: THE PYRETRON OXYGEN BURNER, AMERICAN COMBUSTION TECHNOLOGIES, INC.

    EPA Science Inventory

    The Pyretron is a burner which is designed to allow for the injection of oxygen into the combustion air stream for the purpose of increasing the efficiency of a hazardous waste incinerator. The SITE demonstration of the Pyretron took place at the U.S. EPA's Combustion Re...

  17. Combustion Dynamics and Stability Modeling of a Liquid Oxygen/RP-2 Oxygen-Rich Staged Combustion Preburner and Thrust Chamber Assembly with Gas-Centered Swirl Coaxial Injector Elements

    NASA Technical Reports Server (NTRS)

    Casiano, M. J.; Kenny, R. J.; Protz, C. S.; Garcia, C. P.; Simpson, S. P.; Elmore, J. L.; Fischbach, S. R.; Giacomoni, C. B.; Hulka, J. R.

    2016-01-01

    The Combustion Stability Tool Development (CSTD) project, funded by the Air Force Space and Missile Systems Center, began in March 2015 supporting a renewed interest in the development of a liquid oxygen/hydrocarbon, oxygen-rich combustion engine. The project encompasses the design, assembly, and hot-fire testing of the NASA Marshall Space Flight Center 40-klbf Integrated Test Rig (MITR). The test rig models a staged-combustion configuration by combining an oxygen-rich preburner (ORPB), to generate hot gas, with a thrust chamber assembly (TCA) using gas-centered swirl coaxial injector elements. There are five separately designed interchangeable injectors in the TCA that each contain 19- or 27- injector elements. A companion paper in this JANNAF conference describes the design characteristics, rationale, and fabrication issues for all the injectors. The data acquired from a heavily instrumented rig encompasses several injectors, several operating points, and stability bomb tests. Another companion paper in this JANNAF conference describes this test program in detail. In this paper, dynamic data from the hot-fire testing is characterized and used to identify the responses in the ORPB and TCA. A brief review of damping metrics are discussed and applied as a measure of stability margin for damped acoustic modes. Chug and longitudinal combustion stability models and predictions are described which includes new dynamic models for compressible flow through an orifice and a modification to incorporate a third feed line for inclusion of the fuel-film coolant. Flow-acoustics finite element modeling is used to investigate the anticipated TCA acoustics, the effects of injector element length on stability margin, and the potential use of an ORPB orifice trip ring for improving longitudinal stability margin.

  18. Performance and Stability Analyses of Rocket Combustion Devices Using Liquid Oxygen/Liquid Methane Propellants

    NASA Technical Reports Server (NTRS)

    Hulka, James R.; Jones, G. W.

    2010-01-01

    Liquid rocket engines using oxygen and methane propellants are being considered by the National Aeronautics and Space Administration (NASA) for in-space vehicles. This propellant combination has not been previously used in flight-qualified engine systems, so limited test data and analysis results are available at this stage of early development. NASA has funded several hardware-oriented programs with oxygen and methane propellants over the past several years with the Propulsion and Cryogenic Advanced Development (PCAD) project, under the Exploration Technology Development Program. As part of this effort, NASA Marshall Space Flight Center has conducted combustion, performance, and combustion stability analyses of several of the configurations on these programs. This paper summarizes these analyses. Test and analysis results of impinging and coaxial element injectors using liquid oxygen and liquid methane propellants are included. Several cases with gaseous methane are included for reference. Several different thrust chamber configurations have been modeled, including thrust chambers with multi-element like-on-like and swirl coax element injectors tested at NASA MSFC, and a unielement chamber with shear and swirl coax injectors tested at The Pennsylvania State University. Configurations were modeled with two one-dimensional liquid rocket combustion analysis codes, the Rocket Combustor Interaction Design and Analysis (ROCCID), and the Coaxial Injector Combustion Model (CICM). Significant effort was applied to show how these codes can be used to model combustion and performance with oxygen/methane propellants a priori, and what anchoring or calibrating features need to be applied or developed in the future. This paper describes the test hardware configurations, presents the results of all the analyses, and compares the results from the two analytical methods.

  19. Experimental and theoretical study of iron and mild steel combustion in oxygen flows

    NASA Astrophysics Data System (ADS)

    El-Rabii, Hazem; Kazakov, Kirill A.; Muller, Maryse

    2017-03-01

    The effects of oxygen flow speed and pressure on the iron and mild steel combustion are investigated experimentally and theoretically. The studied specimens are vertical cylindrical rods subjected to an axial oxygen flow and ignited at the upper end by laser irradiation. Three main stages of the combustion process have been identified experimentally: (1) induction period, during which the rod is heated until an intensive metal oxidation begins at its upper end; (2) static combustion, during which a laminar liquid "cap'' slowly grows on the upper rod end, and, after the liquid cap detachment from the sample; (3) dynamic combustion, which is characterized by a rapid metal consumption and turbulent liquid motions. An analytical description of these stages is given. In particular, a model of the dynamic combustion is constructed based on the turbulent oxygen transport through the liquid metal-oxide flow. This model yields a simple expression for the fraction of metal burned in the process and allows one to calculate the normal propagation speed of the solid metal-liquid interface as a function of the oxygen flow speed and pressure. A comparison of the theory with the experimental results is made, and its potential application is mentioned.

  20. THE SITE DEMONSTRATION OF THE AMERICAN COMBUSTION PYRETRON OXYGEN-ENHANCED BURNER

    EPA Science Inventory

    A demonstration of the American Combustion PyretronTM oxygen-enhanced burner ws conducted under the Superfund Innovative Technology Evaluation (SITE) program. The Demonstration was conducted at the U.S. EPA's Combustion Research Facility (CRF) in Jefferson, Arkansas....

  1. Oxygen Handling and Cooling Options in High Temperature Electrolysis Plants

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Manohar S. Sohal; J. Stephen Herring

    2008-07-01

    Idaho National Laboratory is working on a project to generate hydrogen by high temperature electrolysis (HTE). In such an HTE system, safety precautions need to be taken to handle high temperature oxygen at ~830°C. This report is aimed at addressing oxygen handling in a HTE plant.. Though oxygen itself is not flammable, most engineering material, including many gases and liquids, will burn in the presence of oxygen under some favorable physicochemical conditions. At present, an absolute set of rules does not exist that can cover all aspects of oxygen system design, material selection, and operating practices to avoid subtle hazardsmore » related to oxygen. Because most materials, including metals, will burn in an oxygen-enriched environment, hazards are always present when using oxygen. Most materials will ignite in an oxygen-enriched environment at a temperature lower than that in air, and once ignited, combustion rates are greater in the oxygen-enriched environment. Even many metals, if ignited, burn violently in an oxygen-enriched environment. However, these hazards do not preclude the operations and systems involving oxygen. Oxygen can be safely handled and used if all the materials in a system are not flammable in the end-use environment or if ignition sources are identified and controlled. In fact, the incidence of oxygen system fires is reported to be low with a probability of about one in a million. This report is a practical guideline and tutorial for the safe operation and handling of gaseous oxygen in high temperature electrolysis system. The intent is to provide safe, practical guidance that permits the accomplishment of experimental operations at INL, while being restrictive enough to prevent personnel endangerment and to provide reasonable facility protection. Adequate guidelines are provided to govern various aspects of oxygen handling associated with high temperature electrolysis system to generate hydrogen. The intent here is to present

  2. Waste plastics as supplemental fuel in the blast furnace process: improving combustion efficiencies.

    PubMed

    Kim, Dongsu; Shin, Sunghye; Sohn, Seungman; Choi, Jinshik; Ban, Bongchan

    2002-10-14

    The possibility of using waste plastics as a source of secondary fuel in a blast furnace has been of recent interest. The success of this process, however, will be critically dependent upon the optimization of operating systems. For instance, the supply of waste plastics must be reliable as well as economically attractive compared with conventional secondary fuels such as heavy oil, natural gas and pulverized coal. In this work, we put special importance on the improvement of the combustibility of waste plastics as a way to enhance energy efficiency in a blast furnace. As experimental variables to approach this target, the effects of plastic particle size, blast temperature, and the level of oxygen enrichment were investigated using a custom-made blast model designed to simulate a real furnace. Lastly, the combustion efficiency of the mixture of waste plastics and pulverized coal was tested. The observations made from these experiments led us to the conclusion that with the increase of both blast temperature and the level of oxygen enrichment, and with a decrease in particle size, the combustibility of waste polyethylene could be improved at a given distance from the tuyere. Also it was found that the efficiency of coal combustion decreased with the addition of plastics; however, the combustion efficiency of mixture could be comparable at a longer distance from the tuyere.

  3. Combustion Stability Analyses of Coaxial Element Injectors with Liquid Oxygen/Liquid Methane Propellants

    NASA Technical Reports Server (NTRS)

    Hulka, J. R.

    2010-01-01

    Liquid rocket engines using oxygen and methane propellants are being considered by the National Aeronautics and Space Administration (NASA) for in-space vehicles. This propellant combination has not been previously used in a flight-qualified engine system, so limited test data and analysis results are available at this stage of early development. NASA has funded several hardware-oriented activities with oxygen and methane propellants over the past several years with the Propulsion and Cryogenic Advanced Development (PCAD) project, under the Exploration Technology Development Program. As part of this effort, the NASA Marshall Space Flight Center has conducted combustion stability analyses of several of the configurations. This paper presents test data and analyses of combustion stability from the recent PCAD-funded test programs at the NASA MSFC. These test programs used swirl coaxial element injectors with liquid oxygen and liquid methane propellants. Oxygen was injected conventionally in the center of the coaxial element, and swirl was provided by tangential entry slots. Injectors with 28-element and 40-element patterns were tested with several configurations of combustion chambers, including ablative and calorimeter spool sections, and several configurations of fuel injection design. Low frequency combustion instability (chug) occurred with both injectors, and high-frequency combustion instability occurred at the first tangential (1T) transverse mode with the 40-element injector. In most tests, a transition between high-amplitude chug with gaseous methane flow and low-amplitude chug with liquid methane flow was readily observed. Chug analyses of both conditions were conducted using techniques from Wenzel and Szuch and from the Rocket Combustor Interactive Design and Analysis (ROCCID) code. The 1T mode instability occurred in several tests and was apparent by high-frequency pressure measurements as well as dramatic increases in calorimeter-measured heat flux

  4. Combustion Processes in the Aerospace Environment

    NASA Technical Reports Server (NTRS)

    Huggett, Clayton

    1969-01-01

    The aerospace environment introduces new and enhanced fire hazards because the special atmosphere employed may increase the frequency and intensity of fires, because the confinement associated with aerospace systems adversely affects the dynamics of fire development and control, and because the hostile external environments limit fire control and rescue operations. Oxygen enriched atmospheres contribute to the fire hazard in aerospace systems by extending the list of combustible fuels, increasing the probability of ignition, and increasing the rates of fire spread and energy release. A system for classifying atmospheres according to the degree of fire hazard, based on the heat capacity of the atmosphere per mole of oxygen, is suggested. A brief exploration of the dynamics of chamber fires shows that such fires will exhibit an exponential growth rate and may grow to dangerous size in a very short time. Relatively small quantities of fuel and oxygen can produce a catastrophic fire in a closed chamber.

  5. Guide for Oxygen Compatibility Assessments on Oxygen Components and Systems

    NASA Technical Reports Server (NTRS)

    Rosales, Keisa R.; Shoffstall, Michael S.; Stoltzfus, Joel M.

    2007-01-01

    Understanding and preventing fire hazards is necessary when designing, maintaining, and operating oxygen systems. Ignition risks can be minimized by controlling heat sources and using materials that will not ignite or will not support burning in the end-use environment. Because certain materials are more susceptible to ignition in oxygen-enriched environments, a compatibility assessment should be performed before the component is introduced into an oxygen system. This document provides an overview of oxygen fire hazards and procedures that are consistent with the latest versions of American Society for Testing and Materials (ASTM) Standards G63 (1999) and G94 (2005) to address fire hazards associated with oxygen systems. This document supersedes the previous edition, NASA Technical Memorandum 104823, Guide for Oxygen Hazards Analyses on Components and Systems (1996). The step-by-step oxygen compatibility assessment method described herein (see Section 4) enables oxygen-system designers, system engineers, and facility managers to determine areas of concern with respect to oxygen compatibility and, ultimately, prevent damage to a system or injury to personnel.

  6. An Elementary Overview of the Selection of Materials for Service in Oxygen-Enriched Environments

    NASA Technical Reports Server (NTRS)

    Davis, Samuel Eddie

    2012-01-01

    The process for selecting materials for use in oxygen or oxygen-enriched environments is one that continues to be investigated by many industries due to the importance to those industries of oxygen systems. There are several excellent resources available to assist oxygen systems design engineers and end-users, with the most comprehensive being ASTM MNL-36, Safe Use of Oxygen and Oxygen Systems: Handbook for Design, Operation and Maintenance, 2nd Edition. ASTM also makes available several standards for oxygen systems. However, the ASTM publications are extremely detailed, and typically designed for professionals who already possess a working knowledge of oxygen systems. No notable resource exists, whether an ASTM or other organizational publication, which can be used to educate engineers or technicians who have no prior knowledge of the nuances of oxygen system design and safety. This paper will fill the void for information needed by organizations that design or operate oxygen systems. The information in this paper is not new information, but is a concise and easily understood summary of selecting materials for oxygen systems. This paper will serve well as an employee s first introduction to oxygen system materials selection, and probably the employee s first introduction to ASTM.

  7. Photographic Study of Combustion in a Rocket Engine I : Variation in Combustion of Liquid Oxygen and Gasoline with Seven Methods of Propellant Injection

    NASA Technical Reports Server (NTRS)

    Bellman, Donald R; Humphrey, Jack C

    1948-01-01

    Motion pictures at camera speeds up to 3000 frames per second were taken of the combustion of liquid oxygen and gasoline in a 100-pound-thrust rocket engine. The engine consisted of thin contour and injection plates clamped between two clear plastic sheets forming a two-dimensional engine with a view of the entire combustion chamber and nozzle. A photographic investigation was made of the effect of seven methods of propellant injection on the uniformity of combustion. From the photographs, it was found that the flame front extended almost to the faces of the injectors with most of the injection methods, all the injection systems resulted in a considerable nonuniformity of combustion, and luminosity rapidly decreased in the divergent part of the nozzle. Pressure vibration records indicated combustion vibrations that approximately corresponded to the resonant frequencies of the length and the thickness of the chamber. The combustion temperature divided by the molecular weight of the combustion gases as determined from the combustion photographs was about 50 to 70 percent of the theoretical value.

  8. A new bomb-combustion system for tritium extraction.

    PubMed

    Marsh, Richard I; Croudace, Ian W; Warwick, Phillip E; Cooper, Natasha; St-Amant, Nadereh

    2017-01-01

    Quantitative extraction of tritium from a sample matrix is critical to efficient measurement of the low-energy pure beta emitter. Oxidative pyrolysis using a tube furnace (Pyrolyser) has been adopted as an industry standard approach for the liberation of tritium (Warwick et al. in Anal Chim Acta 676:93-102, 2010) however pyrolysis of organic-rich materials can be problematic. Practically, the mass of organic rich sample combusted is typically limited to <1 g to minimise the possibility of incomplete combustion. This can have an impact on both the limit of detection that can be achieved and how representative the subsample is of the bulk material, particularly in the case of heterogeneous soft waste. Raddec International Ltd (Southampton, UK), in conjunction with GAU-Radioanalytical, has developed a new high-capacity oxygen combustion bomb (the Hyperbaric Oxidiser; HBO 2 ) to address this challenge. The system is capable of quantitatively combusting samples of 20-30 g under an excess of oxygen, facilitating rapid extraction of total tritium from a wide range sample types.

  9. Oil shale retorting and combustion system

    DOEpatents

    Pitrolo, Augustine A.; Mei, Joseph S.; Shang, Jerry Y.

    1983-01-01

    The present invention is directed to the extraction of energy values from l shale containing considerable concentrations of calcium carbonate in an efficient manner. The volatiles are separated from the oil shale in a retorting zone of a fluidized bed where the temperature and the concentration of oxygen are maintained at sufficiently low levels so that the volatiles are extracted from the oil shale with minimal combustion of the volatiles and with minimal calcination of the calcium carbonate. These gaseous volatiles and the calcium carbonate flow from the retorting zone into a freeboard combustion zone where the volatiles are burned in the presence of excess air. In this zone the calcination of the calcium carbonate occurs but at the expense of less BTU's than would be required by the calcination reaction in the event both the retorting and combustion steps took place simultaneously. The heat values in the products of combustion are satisfactorily recovered in a suitable heat exchange system.

  10. Application of Oxygen-Enriched Aeration in the Production of Bacitracin by Bacillus licheniformis

    PubMed Central

    Flickinger, M. C.; Perlman, D.

    1979-01-01

    The physiological effects of controlling the dissolved oxygen tension at 0.01, 0.02, and 0.05 atm by the use of oxygen-enriched aeration were investigated during growth and bacitracin production by Bacillus licheniformis ATCC 10716. Up to a 2.35-fold increase in the final antibiotic yield and a 4-fold increase in the rate of bacitracin synthesis were observed in response to O2-enriched aeration. The increase in antibiotic production was accompanied by increased respiratory activity and an increase in the specific productivity of the culture from 1.3 to 3.6 g of antibiotic per g of cell mass produced. Oxygen enrichment of the aeration decreased medium carbohydrate uptake and the maximum specific growth rate of B. licheniformis from 0.6 h−1 to as low as 0.15 h−1, depending upon the level of enrichment and the conditions of oxygen transfer rate (impeller speed). The response of this culture to O2 enrichment suggests that this method of controlling the dissolved oxygen tension for antibiotic-producing cultures may simulate conditions that would occur if the carbon source were fed slowly, as is often employed to optimize antibiotic production. Analysis of the biologically active bacitracins produced by B. licheniformis ATCC 10716 suggested that the ratio of biologically active peptides was not changed by O2 enrichment, nor were any new biologically active compounds formed. Images PMID:34361

  11. Additively Manufactured Metals in Oxygen Systems Project

    NASA Technical Reports Server (NTRS)

    Tylka, Jonathan

    2015-01-01

    Metals produced by additive manufacturing methods, such as Powder Bed Fusion Technology, are now mature enough to be considered for qualification in human spaceflight oxygen systems. The mechanical properties of metals produced through AM processes are being systematically studied. However, it is unknown whether AM metals in oxygen applications may present an increased risk of flammability or ignition as compared to wrought metals of the same metallurgical composition due to increased porosity. Per NASA-STD-6001B materials to be used in oxygen system applications shall be based on flammability and combustion test data, followed by a flammability assessment. Without systematic flammability and ignition testing in oxygen there is no credible method for NASA to accurately evaluate the risk of using AM metals in oxygen systems.

  12. NOx reduction in combustion with concentrated coal streams and oxygen injection

    DOEpatents

    Kobayashi, Hisashi; Bool, III, Lawrence E.; Snyder, William J.

    2004-03-02

    NOx formation in the combustion of solid hydrocarbonaceous fuel such as coal is reduced by obtaining, from the incoming feed stream of fuel solids and air, a stream having a ratio of fuel solids to air that is higher than that of the feed steam, and injecting the thus obtained stream and a small amount of oxygen to a burner where the fuel solids are combusted.

  13. Oxygen index: An approximate value for the evaluation of combustion characteristics

    NASA Technical Reports Server (NTRS)

    Zartmann, I.; Reinwardt, D.; Franke, A.

    1986-01-01

    The oxygen index has gained international recognition for the determination of combustion characteristics of plastic material. The amounts of oxygen and nitrogen were more accurately determined for existing test equipment in order to specify the oxygen index as precisely and as reproducible as possible. Parameters are outlined such as the size of the ignition flame, ignition of test pieces, test piece sizes and test temperature. The minimum oxygen index was determined by the dimension and duration of the fire. The results are sufficiently accurate for factory operating conditions and are also reproducible.

  14. Testing metals and alloys for use in oxygen systems

    NASA Technical Reports Server (NTRS)

    Stoltzfus, Joel M.

    1986-01-01

    When oxygen is present in high concentrations or large quantities, as in oxygen-based life-support systems, the likelihood of combustion and the probable intensity of a conflagration increase, together with the severity of the damage caused. Even stainless steel will burn vigorously when ignited in a 1000-psi oxygen environment. The hazards involved in the use of oxygen increase with system operation at the elevated temperatures typical of propulsion systems. Fires in oxygen systems are generally catastrophic, causing a threat to life in manned vehicles. When mechanical components of a mechanism generate friction heat in the presence of oxygen, many commonly used metal alloys ignite and burn. Attention is presently given to frictional heating, particle impact, and flame propagation tests conducted in oxygen environments.

  15. Powdered aluminum and oxygen rocket propellants: Subscale combustion experiments

    NASA Technical Reports Server (NTRS)

    Meyer, Mike L.

    1993-01-01

    Aluminum combined with oxygen has been proposed as a potential lunar in situ propellant for ascent/descent and return missions for future lunar exploration. Engine concepts proposed to use this propellant have not previously been demonstrated, and the impact on performance from combustion and two-phase flow losses could only be estimated. Therefore, combustion tests were performed for aluminum and aluminum/magnesium alloy powders with oxygen in subscale heat-sink rocket engine hardware. The metal powder was pneumatically injected, with a small amount of nitrogen, through the center orifice of a single element O-F-O triplet injector. Gaseous oxygen impinged on the fuel stream. Hot-fire tests of aluminum/oxygen were performed over a mixture ratio range of 0.5 to 3.0, and at a chamber pressure of approximately 480 kPa (70 psia). The theoretical performance of the propellants was analyzed over a mixture ratio range of 0.5 to 5.0. In the theoretical predictions the ideal one-dimensional equilibrium rocket performance was reduced by loss mechanisms including finite rate kinetics, two-dimensional divergence losses, and boundary layer losses. Lower than predicted characteristic velocity and specific impulse performance efficiencies were achieved in the hot-fire tests, and this was attributed to poor mixing of the propellants and two-phase flow effects. Several tests with aluminum/9.8 percent magnesium alloy powder did not indicate any advantage over the pure aluminum fuel.

  16. Oxy-fuel combustion with integrated pollution control

    DOEpatents

    Patrick, Brian R [Chicago, IL; Ochs, Thomas Lilburn [Albany, OR; Summers, Cathy Ann [Albany, OR; Oryshchyn, Danylo B [Philomath, OR; Turner, Paul Chandler [Independence, OR

    2012-01-03

    An oxygen fueled integrated pollutant removal and combustion system includes a combustion system and an integrated pollutant removal system. The combustion system includes a furnace having at least one burner that is configured to substantially prevent the introduction of air. An oxygen supply supplies oxygen at a predetermine purity greater than 21 percent and a carbon based fuel supply supplies a carbon based fuel. Oxygen and fuel are fed into the furnace in controlled proportion to each other and combustion is controlled to produce a flame temperature in excess of 3000 degrees F. and a flue gas stream containing CO2 and other gases. The flue gas stream is substantially void of non-fuel borne nitrogen containing combustion produced gaseous compounds. The integrated pollutant removal system includes at least one direct contact heat exchanger for bringing the flue gas into intimated contact with a cooling liquid to produce a pollutant-laden liquid stream and a stripped flue gas stream and at least one compressor for receiving and compressing the stripped flue gas stream.

  17. HIGH ARSENIC CONCENTRATIONS AND ENRICHED SULFUR AND OXYGEN ISOTOPES IN A FRACTURED-BEDROCK GROUND-WATER SYSTEM

    EPA Science Inventory

    Elevated arsenic concentrations are coincident with enriched sulfur and oxygen isotopes of sulfate in bedrock ground water within Kelly's Cove watershed, Northport, Maine, USA. Interpretation of the data is complicated by the lack of correlations between sulfate concentrations an...

  18. Injection Principles from Combustion Studies in a 200-Pound-Thrust Rocket Engine Using Liquid Oxygen and Heptane

    NASA Technical Reports Server (NTRS)

    Heidmann, M. F.; Auble, C. M.

    1955-01-01

    The importance of atomizing and mixing liquid oxygen and heptane was studied in a 200-pound-thrust rocket engine. Ten injector elements were used with both steel and transparent chambers. Characteristic velocity was measured over a range of mixture ratios. Combustion gas-flow and luminosity patterns within the chamber were obtained by photographic methods. The results show that, for efficient combustion, the propellants should be both atomized and mixed. Heptane atomization controlled the combustion rate to a much larger extent than oxygen atomization. Induced mixing, however, was required to complete combustion in the smallest volume. For stable, high-efficiency combustion and smooth engine starts, mixing after atomization was most promising.

  19. Hot-Fire Test Results of an Oxygen/RP-2 Multi-Element Oxidizer-Rich Staged-Combustion Integrated Test Article

    NASA Technical Reports Server (NTRS)

    Hulka, J. R.; Protz, C. S.; Garcia, C. P.; Casiano, M. J.; Parton, J. A.

    2016-01-01

    As part of the Combustion Stability Tool Development project funded by the Air Force Space and Missile Systems Center, the NASA Marshall Space Flight Center was contracted to assemble and hot-fire test a multi-element integrated test article demonstrating combustion characteristics of an oxygen/hydrocarbon propellant oxidizer-rich staged-combustion engine thrust chamber. Such a test article simulates flow through the main injectors of oxygen/kerosene oxidizer-rich staged combustion engines such as the Russian RD-180 or NK-33 engines, or future U.S.-built engine systems such as the Aerojet-Rocketdyne AR-1 engine or the Hydrocarbon Boost program demonstration engine. For the thrust chamber assembly of the test article, several configurations of new main injectors, using relatively conventional gas-centered swirl coaxial injector elements, were designed and fabricated. The design and fabrication of these main injectors are described in a companion paper at this JANNAF meeting. New ablative combustion chambers were fabricated based on hardware previously used at NASA for testing at similar size and pressure. An existing oxygen/RP-1 oxidizer-rich subscale preburner injector from a previous NASA-funded program, along with existing and new inter-connecting hot gas duct hardware, were used to supply the oxidizer-rich combustion products to the oxidizer circuit of the main injector of the thrust chamber. Results from independent hot-fire tests of the preburner injector in a combustion chamber with a sonic throat are described in companion papers at this JANNAF conference. The resulting integrated test article - which includes the preburner, inter-connecting hot gas duct, main injector, and ablative combustion chamber - was assembled at Test Stand 116 at the East Test Area of the NASA Marshall Space Flight Center. The test article was well instrumented with static and dynamic pressure, temperature, and acceleration sensors to allow the collected data to be used for

  20. Coal Combustion Behavior in New Ironmaking Process of Top Gas Recycling Oxygen Blast Furnace

    NASA Astrophysics Data System (ADS)

    Zhou, Zhenfeng; Xue, Qingguo; Tang, Huiqing; Wang, Guang; Wang, Jingsong

    2017-10-01

    The top gas recycling oxygen blast furnace (TGR-OBF) is a new ironmaking process which can significantly reduce the coke ratio and emissions of carbon dioxide. To better understand the coal combustion characteristics in the TGR-OBF, a three dimensional model was developed to simulate the lance-blowpipe-tuyere-raceway of a TGR-OBF. The combustion characteristics of pulverized coal in TGR-OBF were investigated. Furthermore, the effects of oxygen concentration and temperature were also analyzed. The simulation results show that the coal burnout increased by 16.23% compared to that of the TBF. The oxygen content has an obvious effect on the burnout. At 70% oxygen content, the coal burnout is only 21.64%, with a decrease of 50.14% compared to that of TBF. Moreover, the effect of oxygen temperature is also very obvious.

  1. Comparison of waste combustion and waste electrolysis - A systems analysis

    NASA Technical Reports Server (NTRS)

    Holtzapple, Mark T.; Little, Frank E.

    1989-01-01

    A steady state model of a closed environmental system has been developed which includes higher plant growth for food production, and is designed to allow wastes to be combusted or electrolyzed. The stoichiometric equations have been developed to evaluate various trash compositions, food items (both stored and produced), metabolic rates, and crew sizes. The advantages of waste electrolysis versus combustion are: (1) oxygen is not required (which reduces the load on the oxygen producing system); (2) the CO2 and H2 products are produced in pure form (reducing the load on the separators); and (3) nitrogen is converted to nitrate (which is directly usable by plants). Weight tradeoff studies performed using this model have shown that waste electrolysis reduces the life support weight of a 4-person crew by 1000 to 2000 kg.

  2. Skin oxygen tension is improved by immersion in oxygen-enriched water.

    PubMed

    Reading, S A; Yeomans, M; Levesque, C

    2013-12-01

    The perceived health and physiologic functioning of skin depends on adequate oxygen availability. Economical and easily used therapeutic approaches to increase skin oxygenation could improve the subjective appearance of the skin as well as support the management of some cutaneous conditions related to chronic hypoxic ischaemia (e.g. ulcerative wounds). We have tested the hypothesis that the O2 partial pressure of skin (PskO2 ) increases during immersion in water enriched with high levels of dissolved oxygen. A commercially available device was used to produce water containing 45 to 65 mg L(-1) of dissolved O2 . Young adults (YA; n = 7), older adults (OA; n = 13) and older adults with diabetes (OAD; n = 11) completed different experiments that required them to immerse their feet in tap water (<2 mg L(-1) of O2 ; control) or O2 -enriched water (O2 -H2 O; experimental) for 30 min. Transcutaneous oximetry was used to measure PskO2 for 20 min pre- and post-immersion. Pre-immersion mean (standard deviation) PskO2 on the plantar surface of the big toe was 75 (10), 67 (10) and 65 (10) mmHg in YA, OA and OAD, respectively. Post-immersion PskO2 was 244 (25), 193 (28) and 205 (28) mmHg for the same groups. We also show that post-immersion PskO2 varies by location and with advancing age. Water is an effective vehicle for transporting dissolved O2 across the skin surface and could be used as a basis for development of economical therapeutic approaches that improve skin oxygen tension to support skin health and function. © 2013 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

  3. Importance of atomic oxygen in preheating zone in plasma-assisted combustion of a steady-state premixed burner flame

    NASA Astrophysics Data System (ADS)

    Zaima, K.; Akashi, H.; Sasaki, K.

    2015-09-01

    It is widely believed that electron impact processes play essential roles in plasma-assisted combustion. However, the concrete roles of high-energy electrons have not been fully understood yet. In this work, we examined the density of atomic oxygen in a premixed burner flame with the superposition of dielectric barrier discharge (DBD). The density of atomic oxygen in the reaction zone was not affected by the superposition of DBD, indicating that the amount of atomic oxygen produced by combustion reactions was much larger than that produced by electron impact processes. On the other hand, in the preheating zone, we observed high-frequency oscillation of the density of atomic oxygen at the timings of the pulsed current of DBD. The oscillation suggests the rapid consumption of additional atomic oxygen by combustion reactions. A numerical simulation using Chemkin indicates the shortened ignition delay time when adding additional atomic oxygen in the period of low-temperature oxidation. The present results reveals the importance of atomic oxygen, which is produced by the effect of high-energy electrons, in the preheating zone in plasma-assisted combustion of the steady-state premixed burner flame.

  4. New type of microengine using internal combustion of hydrogen and oxygen

    NASA Astrophysics Data System (ADS)

    Svetovoy, Vitaly B.; Sanders, Remco G. P.; Ma, Kechun; Elwenspoek, Miko C.

    2014-03-01

    Microsystems become part of everyday life but their application is restricted by lack of strong and fast motors (actuators) converting energy into motion. For example, widespread internal combustion engines cannot be scaled down because combustion reactions are quenched in a small space. Here we present an actuator with the dimensions 100 × 100 × 5 μm3 that is using internal combustion of hydrogen and oxygen as part of its working cycle. Water electrolysis driven by short voltage pulses creates an extra pressure of 0.5-4 bar for a time of 100-400 μs in a chamber closed by a flexible membrane. When the pulses are switched off this pressure is released even faster allowing production of mechanical work in short cycles. We provide arguments that this unexpectedly fast pressure decrease is due to spontaneous combustion of the gases in the chamber. This actuator is the first step to truly microscopic combustion engines.

  5. Chemicl-looping combustion of coal with metal oxide oxygen carriers

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Siriwardane, R.; Tian, H.; Richards, G.

    2009-01-01

    The combustion and reoxidation properties of direct coal chemical-looping combustion (CLC) over CuO, Fe2O3, Co3O4, NiO, and Mn2O3 were investigated using thermogravimetric analysis (TGA) and bench-scale fixed-bed flow reactor studies. When coal is heated in either nitrogen or carbon dioxide (CO2), 50% of weight loss was observed because of partial pyrolysis, consistent with the proximate analysis. Among various metal oxides evaluated, CuO showed the best reaction properties: CuO can initiate the reduction reaction as low as 500 °C and complete the full combustion at 700 °C. In addition, the reduced copper can be fully reoxidized by air at 700 °C.more » The combustion products formed during the CLC reaction of the coal/metal oxide mixture are CO2 and water, while no carbon monoxide was observed. Multicycle TGA tests and bench-scale fixed-bed flow reactor tests strongly supported the feasibility of CLC of coal by using CuO as an oxygen carrier. Scanning electron microscopy (SEM) images of solid reaction products indicated some changes in the surface morphology of a CuO-coal sample after reduction/oxidation reactions at 800 °C. However, significant surface sintering was not observed. The interactions of fly ash with metal oxides were investigated by X-ray diffraction and thermodynamic analysis. Overall, the results indicated that it is feasible to develop CLC with coal by metal oxides as oxygen carriers.« less

  6. Regenerable mixed copper-iron-inert support oxygen carriers for solid fuel chemical looping combustion process

    DOEpatents

    Siriwardane, Ranjani V.; Tian, Hanjing

    2016-12-20

    The disclosure provides an oxygen carrier for a chemical looping cycle, such as the chemical looping combustion of solid carbonaceous fuels, such as coal, coke, coal and biomass char, and the like. The oxygen carrier is comprised of at least 24 weight % (wt %) CuO, at least 10 wt % Fe2O3, and an inert support, and is typically a calcine. The oxygen carrier exhibits a CuO crystalline structure and an absence of iron oxide crystalline structures under XRD crystallography, and provides an improved and sustained combustion reactivity in the temperature range of 600.degree. C.-1000.degree. C. particularly for solid fuels such as carbon and coal.

  7. The effect of intraoral suction on oxygen-enriched surgical environments: a mechanism for reducing the risk of surgical fires.

    PubMed

    VanCleave, Andrea M; Jones, James E; McGlothlin, James D; Saxen, Mark A; Sanders, Brian J; Vinson, LaQuia A

    2014-01-01

    In this study, a mechanical model was applied in order to replicate potential surgical fire conditions in an oxygen-enriched environment with and without high-volume suction typical for dental surgical applications. During 41 trials, 3 combustion events were measured: an audible pop, a visible flash of light, and full ignition. In at least 11 of 21 trials without suction, all 3 conditions were observed, sometimes with an extent of fire that required early termination of the experimental trial. By contrast, in 18 of 20 with-suction trials, ignition did not occur at all, and in the 2 cases where ignition did occur, the fire was qualitatively a much smaller, candle-like flame. Statistically comparing these 3 combustion events in the no-suction versus with-suction trials, ignition (P = .0005), audible pop (P = .0211), and flash (P = .0092) were all significantly more likely in the no-suction condition. These results suggest a possible significant and new element to be added to existing surgical fire safety protocols toward making surgical fires the "never-events" they should be.

  8. Intramolecular distribution of stable nitrogen and oxygen isotopes of nitrous oxide emitted during coal combustion.

    PubMed

    Ogawa, Mitsuteru; Yoshida, Naohiro

    2005-11-01

    The intramolecular distribution of stable isotopes in nitrous oxide that is emitted during coal combustion was analyzed using an isotopic ratio mass spectrometer equipped with a modified ion collector system (IRMS). The coal was combusted in a test furnace fitted with a single burner and the flue gases were collected at the furnace exit following removal of SO(x), NO(x), and H2O in order to avoid the formation of artifact nitrous oxide. The nitrous oxide in the flue gases proved to be enriched in 15N relative to the fuel coal. In air-staged combustion experiments, the staged air ratio was controlled over a range of 0 (unstaged combustion), 20%, and 30%. As the staged air ratio increased, the delta15N and delta18O of the nitrous oxide in the flue gases became depleted. The central nitrogen of the nitrous oxide molecule, N(alpha), was enriched in 15N relative to that occupying the end position of the molecule, N(beta), but this preference, expressed as delta15N(alpha)-delta15N(beta), decreased with the increase in the staged air ratio. Thermal decomposition and hydrogen reduction experiments carried out using a tube reactor allowed qualitative estimates of the kinetic isotope effects that occurred during the decomposition of the nitrous oxide and quantitative estimates of the extent to which the nitrous oxide had decomposed. The site preference of nitrous oxide increased with the extent of the decomposition reactions. Assuming that no site preference exists in nitrous oxide before decomposition, the behavior of nitrous oxide in the test combustion furnace was analyzed using the Rayleigh equation based on a single distillation model. As a result, the extent of decomposition of nitrous oxide was estimated as 0.24-0.26 during the decomposition reaction governed by the thermal decomposition and as 0.35-0.38 during the decomposition reaction governed by the hydrogen reduction in staged combustion. The intramolecular distribution of nitrous oxide can be a valuable

  9. Particulate Formation from a Copper Oxide-Based Oxygen ...

    EPA Pesticide Factsheets

    Attrition behavior and particle loss of a copper oxide-based oxygen carrier from a methane chemical looping combustion (CLC) process was investigated in a fluidized bed reactor. The aerodynamic diameters of most elutriated particulates, after passing through a horizontal settling duct, range between 2 and 5 μm. A notable number of submicron particulates are also identified. Oxygen carrier attrition was observed to lead to increased CuO loss resulting from the chemical looping reactions, i.e., Cu is enriched in small particles generated primarily from fragmentation in the size range of 10-75 μm. Cyclic reduction and oxidation reactions in CLC have been determined to weaken the oxygen carrier particles, resulting in increased particulate emission rates when compared to oxygen carriers without redox reactions. The generation rate for particulates < 10 μm was found to decrease with progressive cycles over as-prepared oxygen carrier particles and then reach a steady state. The surface of the oxygen carrier is also found to be coarsened due to a Kirkendall effect, which also explains the enrichment of Cu on particle surfaces and in small particles. As a result, it is important to collect and reprocess small particles generated from chemical looping processes to reduce oxygen carrier loss. The redox reactions associated with chemical looping combustion play an important role in particle attrition in the fluidized bed. Reaction-induced local stresses, due to the r

  10. Deuterium enrichment by selective photoinduced dissociation of a multihalogenated organic compound

    DOEpatents

    Marling, John B.; Herman, Irving P.

    1981-01-01

    A method for deuterium enrichment by photoinduced dissociation which uses as the deuterium source a multihalogenated organic compound selected from the group consisting of a dihalomethane, a trihalomethane, a 1,2-dihaloethene, a trihaloethene, a tetrahaloethane and a pentahaloethane. The multihalogenated organic compound is subjected to intense infrared radiation at a preselected wavelength to selectively excite and thereby induce dissociation of substantially only those molecules containing deuterium to provide a deuterium enriched dissociation product. The deuterium enriched product may be combusted with oxygen to provide deuterium enriched water. The deuterium depleted undissociated molecules may be redeuterated by treatment with a deuterium source such as water.

  11. The balance model of oxygen enrichment of atmospheric air

    NASA Astrophysics Data System (ADS)

    Popov, Alexander

    2013-04-01

    The study of turnover of carbon and oxygen is an important line of scientific investigation. This line takes on special significance in conditions of soil degradation, which leads to the excess content of carbon dioxide and, as result, decrease of oxygen in the atmosphere. The aim of this article is a statement the balance model of oxygen enrichment of atmospheric air (ratio O/C) depending on consumption and assimilation by plants of dissolved organic matter (DOM) and the value of the oxidation-reduction potential (Eh). Basis of model was the following: green vascular plants are facultative heterotrophic organisms with symbiotic digestion and nutrition. According to the trophology viewpoint, the plant consumption of organic compounds broadens greatly a notion about the plant nutrition and ways of its regulation. In particular, beside the main known cycle of carbon: plant - litter - humus - carbon dioxide - plant, there is the second carbon cycle (turnover of organic compounds): plant - litter - humus - DOM - plant. The biogeochemical meaning of consumption of organic compounds by plants is that plants build the structural and functional blocks of biological macromolecules in their bodies. It provides receiving of a certain "energy payoff" by plants, which leads to increase of plant biomass by both an inclusion of allochthonous organic molecules in plant tissues, and positive effect of organic compounds on plant metabolic processes. One more of powerful ecological consequence of a heterotrophic nutrition of green plants is oxygen enrichment of atmospheric air. As the organic molecules in the second biological cycle of carbon are built in plants without considerable chemical change, the atmospheric air is enriched on that amount of oxygen, which would be required on oxidation of the organic molecules absorbed by plants, in result. It was accepted that: plant-soil system was climax, the plant community was grassy, initial contents of carbon in phytomass was accepted

  12. 99 Tc NMR determination of the oxygen isotope content in 18 O-enriched water.

    PubMed

    Tarasov, Valerii P; Kirakosyan, Gayana А; German, Konstantin E

    2018-03-01

    99 Tc NMR has been suggested as an original method of evaluating the content of oxygen isotopes in oxygen-18-enriched water, a precursor for the production of radioisotope fluorine-18 used in positron emission tomography. To this end, solutions of NH 4 TcO 4 or NaTcO 4 (up to 0.28 mol/L) with natural abundance of oxygen isotopes in virgin or recycled 18 O-enriched water have been studied by 99 Tc NMR. The method is based on 16 O/ 17 O/ 18 O intrinsic isotope effects in the 99 Tc NMR chemical shifts, and the statistical distribution of oxygen isotopes in the coordination sphere of TcO 4 - and makes it possible to quantify the composition of enriched water by measuring the relative intensities of the 99 Tc NMR signals of the Tc 16 O 4-n 18 O n - isotopologues. Because the oxygen exchange between TcO 4 - and enriched water in neutral and alkaline solutions is characterized by slow kinetics, gaseous HCl was bubbled through a solution for a few seconds to achieve the equilibrium distribution of oxygen isotopes in the Tc coordination sphere without distortion of the oxygen composition of the water. Pertechnetate ion was selected as a probe due to its high stability in solutions and the significant 99 Tc NMR shift induced by a single 16 O→ 18 O substitution (-0.43 ± 0.01 ppm) in TcO 4 - and spin coupling constant 1 J( 99 Tc- 17 O) (131.46 Hz) favourable for the observation of individual signals of Tc 16 O 4-n 18 O n - isotopologues. Copyright © 2017 John Wiley & Sons, Ltd.

  13. Nitrogen spark denoxer

    DOEpatents

    Ng, Henry K.; Novick, Vincent J.; Sekar, Ramanujam R.

    1997-01-01

    A NO.sub.X control system for an internal combustion engine includes an oxygen enrichment device that produces oxygen and nitrogen enriched air. The nitrogen enriched air contains molecular nitrogen that is provided to a spark plug that is mounted in an exhaust outlet of an internal combustion engine. As the nitrogen enriched air is expelled at the spark gap of the spark plug, the nitrogen enriched air is exposed to a pulsating spark that is generated across the spark gap of the spark plug. The spark gap is elongated so that a sufficient amount of atomic nitrogen is produced and is injected into the exhaust of the internal combustion engine. The injection of the atomic nitrogen into the exhaust of the internal combustion engine causes the oxides of nitrogen to be reduced into nitrogen and oxygen such that the emissions from the engine will have acceptable levels of NO.sub.X. The oxygen enrichment device that produces both the oxygen and nitrogen enriched air can include a selectively permeable membrane.

  14. From orbital debris capture systems through internal combustion engines on Mars

    NASA Technical Reports Server (NTRS)

    1991-01-01

    The investigation and conceptualization of an orbital debris collector was the primary area of design. In addition, an alternate structural design for Space Station Freedom and systems supporting resource utilization at Mars and the moon were studied. Hardware for production of oxygen from simulate Mars atmosphere was modified to permit more reliable operation at low pressures (down to 10 mb). An internal combustion engine was altered to study how Mars atmosphere could be used as a diluent to control combustion temperatures and avoid excess Mars propellant production requirements that would result from either methane-rich or oxygen-rich, methane-oxygen combustion. An elastic loop traction system that could be used for lunar construction vehicles was refined to permit testing. A parabolic heat rejection radiator system was designed and built to determine whether it was capable of increasing heat rejection rates during lunar daytime operation. In addition, an alternate space station truss design, utilizing a pre-integrated concept, was studied and found to reduce estimate extravehicular activity (EVA) time and increase the structural integrity when compared to the original Warren truss concept. An orbital-debris-capturing spacecraft design which could be mated with the Orbital Maneuvering Vehicle was studied. The design identified Soviet C-1B boosters as the best targets of opportunity in Earth orbits between an altitude of 900 km and 1100 km and at an inclination of 82.9 deg. A dual robot pallet, which could be spun to match the tumbling rate of the C-1B booster, was developed as the conceptual design.

  15. Design and Fabrication of Oxygen/RP-2 Multi-Element Oxidizer-Rich Staged Combustion Thrust Chamber Injectors

    NASA Technical Reports Server (NTRS)

    Garcia, C. P.; Medina, C. R.; Protz, C. S.; Kenny, R. J.; Kelly, G. W.; Casiano, M. J.; Hulka, J. R.; Richardson, B. R.

    2016-01-01

    As part of the Combustion Stability Tool Development project funded by the Air Force Space and Missile Systems Center, the NASA Marshall Space Flight Center was contracted to assemble and hot-fire test a multi-element integrated test article demonstrating combustion characteristics of an oxygen/hydrocarbon propellant oxidizer-rich staged-combustion engine thrust chamber. Such a test article simulates flow through the main injectors of oxygen/kerosene oxidizer-rich staged combustion engines such as the Russian RD-180 or NK-33 engines, or future U.S.-built engine systems such as the Aerojet-Rocketdyne AR-1 engine or the Hydrocarbon Boost program demonstration engine. On the current project, several configurations of new main injectors were considered for the thrust chamber assembly of the integrated test article. All the injector elements were of the gas-centered swirl coaxial type, similar to those used on the Russian oxidizer-rich staged-combustion rocket engines. In such elements, oxidizer-rich combustion products from the preburner/turbine exhaust flow through a straight tube, and fuel exiting from the combustion chamber and nozzle regenerative cooling circuits is injected near the exit of the oxidizer tube through tangentially oriented orifices that impart a swirl motion such that the fuel flows along the wall of the oxidizer tube in a thin film. In some elements there is an orifice at the inlet to the oxidizer tube, and in some elements there is a sleeve or "shield" inside the oxidizer tube where the fuel enters. In the current project, several variations of element geometries were created, including element size (i.e., number of elements or pattern density), the distance from the exit of the sleeve to the injector face, the width of the gap between the oxidizer tube inner wall and the outer wall of the sleeve, and excluding the sleeve entirely. This paper discusses the design rationale for each of these element variations, including hydraulic, structural

  16. Method and device for determining heats of combustion of gaseous hydrocarbons

    NASA Technical Reports Server (NTRS)

    Singh, Jag J. (Inventor); Sprinkle, Danny R. (Inventor); Puster, Richard L. (Inventor)

    1988-01-01

    A method and device is provided for a quick, accurate and on-line determination of heats of combustion of gaseous hydrocarbons. First, the amount of oxygen in the carrier air stream is sensed by an oxygen sensing system. Second, three individual volumetric flow rates of oxygen, carrier stream air, and hydrocrabon test gas are introduced into a burner. The hydrocarbon test gas is fed into the burner at a volumetric flow rate, n, measured by a flowmeter. Third, the amount of oxygen in the resulting combustion products is sensed by an oxygen sensing system. Fourth, the volumetric flow rate of oxygen is adjusted until the amount of oxygen in the combustion product equals the amount of oxygen previously sensed in the carrier air stream. This equalizing volumetric flow rate is m and is measured by a flowmeter. The heat of combustion of the hydrocrabon test gas is then determined from the ratio m/n.

  17. Enhanced activity and stability of La-doped CeO2 monolithic catalysts for lean-oxygen methane combustion.

    PubMed

    Zhu, Wenjun; Jin, Jianhui; Chen, Xiao; Li, Chuang; Wang, Tonghua; Tsang, Chi-Wing; Liang, Changhai

    2018-02-01

    Effective utilization of coal bed methane is very significant for energy utilization and environment protection. Catalytic combustion of methane is a promising way to eliminate trace amounts of oxygen in the coal bed methane and the key to this technology is the development of high-efficiency catalysts. Herein, we report a series of Ce 1-x La x O 2-δ (x = 0-0.8) monolithic catalysts for the catalytic combustion of methane, which are prepared by citric acid method. The structural characterization shows that the substitution of La enhance the oxygen vacancy concentration and reducibility of the supports and promote the migration of the surface oxygen, as a result improve the catalytic activity of CeO 2 . M-Ce 0.8 La 0.2 O 2-δ (monolithic catalyst, Ce 0.8 La 0.2 O 2-δ coated on cordierite honeycomb) exhibits outstanding activity for methane combustion, and the temperature for 10 and 90% methane conversion are 495 and 580 °C, respectively. Additionally, Ce 0.8 La 0.2 O 2-δ monolithic catalyst presents excellent stability at high temperature. These Ce 1-x La x O 2-δ monolithic materials with a small amount of La incorporation therefore show promises as highly efficient solid solution catalysts for lean-oxygen methane combustion. Graphical abstract ᅟ.

  18. High Pressure and High Temperature State of Oxygen Enriched Ice

    NASA Astrophysics Data System (ADS)

    LI, M.; Zhang, S.; Jeanloz, R.; Militzer, B.

    2016-12-01

    Interior models for Uranus and Neptune include a hydrogen/helium/water outer envelope and a core of rock and metal at the center, with superionic water-rich ice proposed as comprising an intermediate layer. Here we consider an oxygen-enriched ice, such as H2O2 hydrogen peroxide (± water), that could form through chemical reaction between water-rich and underlying rocky (i.e., oxygen-rich) layers. As oxygen and its compounds (e.g., H2O, SiO2) form metallic fluids at pressures above 100-150 GPa, the problem amounts to considering oxygen alloying of semiconducting or metallic water. The density of H2O2 is 1.45 g/cc at ambient pressure and 0° C, increasing to 1.71 g/cc in the solid state at about -20° C. There are no Hugoniot data beyond 30 GPa, so we estimated Hugoniots for H2O2 with different initial densities, using both a mixing model based on Hugoniot data for H2O2 and 1/2 O2 (molar volume summation under pressure) and ab initio calculations for unreacted H2O2. The results agree with each other to pressures of about 200 GPa, and the ab initio calculations show evidence of a superionic state at temperatures as low as 500 K, much lower than for water ice. Hydrogen peroxide is expected to be liquid along planetary isentropes for Uranus and Neptune, suggesting that H2O2 may not be present as a pure compound in these planets. Instead, oxygen-enriched H2O ice may be the relevant form of water and oxygen, and might be produced in the laboratory by way of dynamic compression of H2O2 or laser-heating of statically compressed H2O + O2 and/or H2O2.

  19. Dry low combustion system with means for eliminating combustion noise

    DOEpatents

    Verdouw, Albert J.; Smith, Duane; McCormick, Keith; Razdan, Mohan K.

    2004-02-17

    A combustion system including a plurality of axially staged tubular premixers to control emissions and minimize combustion noise. The combustion system includes a radial inflow premixer that delivers the combustion mixture across a contoured dome into the combustion chamber. The axially staged premixers having a twist mixing apparatus to rotate the fluid flow and cause improved mixing without causing flow recirculation that could lead to pre-ignition or flashback.

  20. Chemical Looping Combustion Reactions and Systems

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Sarofim, Adel; Lighty, JoAnn; Smith, Philip

    2014-03-01

    Chemical Looping Combustion (CLC) is one promising fuel-combustion technology, which can facilitate economic CO{sub 2} capture in coal-fired power plants. It employs the oxidation/reduction characteristics of a metal, or oxygen carrier, and its oxide, the oxidizing gas (typically air) and the fuel source may be kept separate. This topical report discusses the results of four complementary efforts: (5.1) the development of process and economic models to optimize important design considerations, such as oxygen carrier circulation rate, temperature, residence time; (5.2) the development of high-performance simulation capabilities for fluidized beds and the collection, parameter identification, and preliminary verification/uncertainty quantification; (5.3) themore » exploration of operating characteristics in the laboratoryscale bubbling bed reactor, with a focus on the oxygen carrier performance, including reactivity, oxygen carrying capacity, attrition resistance, resistance to deactivation, cost and availability; and (5.4) the identification of kinetic data for copper-based oxygen carriers as well as the development and analysis of supported copper oxygen carrier material. Subtask 5.1 focused on the development of kinetic expressions for the Chemical Looping with Oxygen Uncoupling (CLOU) process and validating them with reported literature data. The kinetic expressions were incorporated into a process model for determination of reactor size and oxygen carrier circulation for the CLOU process using ASPEN PLUS. An ASPEN PLUS process model was also developed using literature data for the CLC process employing an iron-based oxygen carrier, and the results of the process model have been utilized to perform a relative economic comparison. In Subtask 5.2, the investigators studied the trade-off between modeling approaches and available simulations tools. They quantified uncertainty in the high-performance computing (HPC) simulation tools for CLC bed applications

  1. PROGRESS IN DETAILED KINETIC MODELING OF THE COMBUSTION OF OXYGENATED COMPONENTS OF BIOFUELS

    PubMed Central

    Sy Tran, Luc; Sirjean, Baptiste; Glaude, Pierre-Alexandre; Fournet, René; Battin-Leclerc, Frédérique

    2013-01-01

    Due to growing environmental concerns and diminishing petroleum reserves, a wide range of oxygenated species has been proposed as possible substitutes to fossil fuels: alcohols, methyl esters, acyclic and cyclic ethers. After a short review the major detailed kinetic models already proposed in the literature for the combustion of these molecules, the specific classes of reactions considered for modeling the oxidation of acyclic and cyclic oxygenated molecules respectively, are detailed. PMID:23700355

  2. Pressurized chemical-looping combustion of coal with an iron ore-based oxygen carrier

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Xiao, Rui; Song, Min; Zhang, Shuai

    2010-06-15

    Chemical-looping combustion (CLC) is a new combustion technology with inherent separation of CO{sub 2}. Most of the previous investigations on CLC of solid fuels were conducted under atmospheric pressure. A pressurized CLC combined cycle (PCLC-CC) system is proposed as a promising coal combustion technology with potential higher system efficiency, higher fuel conversion, and lower cost for CO{sub 2} sequestration. In this study pressurized CLC of coal with Companhia Valedo Rio Doce (CVRD) iron ore was investigated in a laboratory fixed bed reactor. CVRD iron ore particles were exposed alternately to reduction by 0.4 g of Chinese Xuzhou bituminous coal gasifiedmore » with 87.2% steam/N{sub 2} mixture and oxidation with 5% O{sub 2} in N{sub 2} at 970 C. The operating pressure was varied between 0.1 MPa and 0.6 MPa. First, control experiments of steam coal gasification over quartz sand were performed. H{sub 2} and CO{sub 2} are the major components of the gasification products, and the operating pressure influences the gas composition. Higher concentrations of CO{sub 2} and lower fractions of CO, CH{sub 4}, and H{sub 2} during the reduction process with CVRD iron ore was achieved under higher pressures. The effects of pressure on the coal gasification rate in the presence of the oxygen carrier were different for pyrolysis and char gasification. The pressurized condition suppresses the initial coal pyrolysis process while it also enhances coal char gasification and reduction with iron ore in steam, and thus improves the overall reaction rate of CLC. The oxidation rates and variation of oxygen carrier conversion are higher at elevated pressures reflecting higher reduction level in the previous reduction period. Scanning electron microscope and energy-dispersive X-ray spectroscopy (SEM-EDX) analyses show that particles become porous after experiments but maintain structure and size after several cycles. Agglomeration was not observed in this study. An EDX analysis

  3. Oxygen transport membrane reactor based method and system for generating electric power

    DOEpatents

    Kelly, Sean M.; Chakravarti, Shrikar; Li, Juan

    2017-02-07

    A carbon capture enabled system and method for generating electric power and/or fuel from methane containing sources using oxygen transport membranes by first converting the methane containing feed gas into a high pressure synthesis gas. Then, in one configuration the synthesis gas is combusted in oxy-combustion mode in oxygen transport membranes based boiler reactor operating at a pressure at least twice that of ambient pressure and the heat generated heats steam in thermally coupled steam generation tubes within the boiler reactor; the steam is expanded in steam turbine to generate power; and the carbon dioxide rich effluent leaving the boiler reactor is processed to isolate carbon. In another configuration the synthesis gas is further treated in a gas conditioning system configured for carbon capture in a pre-combustion mode using water gas shift reactors and acid gas removal units to produce hydrogen or hydrogen-rich fuel gas that fuels an integrated gas turbine and steam turbine system to generate power. The disclosed method and system can also be adapted to integrate with coal gasification systems to produce power from both coal and methane containing sources with greater than 90% carbon isolation.

  4. On the influence of singlet oxygen molecules on characteristics of HCCI combustion: A numerical study

    NASA Astrophysics Data System (ADS)

    Starik, A. M.; Kozlov, V. E.; Titova, N. S.

    2013-08-01

    Mechanisms of homogeneous charge compression ignition (HCCI) combustion enhancement are investigated numerically when excited O2(a 1Δg) molecules are produced at different points in the compression stroke. The analysis is conducted with the use of an extended kinetic model involving the submechanism of nitric oxide formation in the presence of singlet oxygen O2(a 1Δg) or O2(b 1Σg +) molecules in the methane-air mixture. It is demonstrated that the abundance of excited O2(a 1Δg) molecules in the mixture even in a small amounts intensifies the ignition and combustion and allows one to control the ignition event in the HCCI engine. Such a method of energy supply in the HCCI engine is much more effective in advancement of combustion timing than mere heating of the mixture, because it leads to acceleration of the chain-branching mechanism. The excitation of O2 molecules to the a 1Δg electronic state makes it possible to organise the successful combustion in the cylinder at diminished initial temperature of the mixture and increase the effective energy released during HCCI combustion. The advance in the value of this energy is much higher than the energy needed for the excitation of oxygen molecules. Moreover, in this case, the output concentration of NO and CO can be reduced significantly.

  5. Intrinsic and metal-doped gallium oxide based high-temperature oxygen sensors for combustion processes

    NASA Astrophysics Data System (ADS)

    Rubio, Ernesto Javier

    Currently, there is enormous interest in research, development and optimization of the combustion processes for energy harvesting. Recent statistical and economic analyses estimated that by improving the coal-based firing/combustion processes in the power plants, savings up to $450-500 million yearly can be achieved. Advanced sensors and controls capable of withstanding extreme environments such as high temperatures, highly corrosive atmospheres, and high pressures are critical to such efficiency enhancement and cost savings. For instance, optimization of the combustion processes in power generation systems can be achieved by sensing, monitoring and control of oxygen, which is a measure of the completeness of the process and can lead to enhanced efficiency and reduced greenhouse gas emissions. However, despite the fact that there exists a very high demand for advanced sensors, the existing technologies suffer from poor 'response and recovery times' and 'long-term stability.' Motivated by the aforementioned technological challenges, the present work was focused on high-temperature (≥700 °C) oxygen sensors for application in power generation systems. The objective of the present work is to investigate nanostructured gallium oxide (2O3) based sensors for oxygen sensing, where we propose to conduct in-depth exploration of the role of refractory metal (tungsten, W, in this case) doping into 2O 3 to enhance the sensitivity, selectivity, stability ("3S" criteria) and reliability of such sensors while keeping cost economical. Tungsten (W) doped gallium oxide (2O3) thin films were deposited via rf-magnetron co-sputtering of W-metal and Ga2O3-ceramic targets. Films were produced by varying the sputtering power applied to the W-target in order to achieve variable W content into 2O3 films while substrate temperature was kept constant at 500 °C. Chemical composition, chemical valence states, microstructure and crystal structure of as-grown and post-annealed W-doped 2O3

  6. Burning of CP Titanium (Grade 2) in Oxygen-Enriched Atmospheres

    NASA Technical Reports Server (NTRS)

    Stoltzfus, Joel M.; Jeffers, Nathan; Gallus, Timothy D.

    2012-01-01

    The flammability in oxygen-enriched atmospheres of commercially pure (CP) titanium rods as a function of diameter and test gas pressure was determined. Test samples of varying diameters were ignited at the bottom and burned upward in 70% O2/balance N2 and in 99.5+% O2 at various pressures. The burning rate of each ignited sample was determined by observing the apparent regression rate of the melting interface (RRMI) of the burning samples. The burning rate or RRMI increased with decreasing test sample diameter and with increasing test gas pressure and oxygen concentration

  7. Attrition Rate of Oxygen Carriers in Chemical Looping Combustion Systems

    NASA Astrophysics Data System (ADS)

    Feilen, Harry Martin

    This project developed an evaluation methodology for determining, accurately and rapidly, the attrition resistance of oxygen carrier materials used in chemical looping technologies. Existing test protocols, to evaluate attrition resistance of granular materials, are conducted under non-reactive and ambient temperature conditions. They do not accurately reflect the actual behavior under the unique process conditions of chemical looping, including high temperatures and cyclic operation between oxidizing and reducing atmospheres. This project developed a test method and equipment that represented a significant improvement over existing protocols. Experimental results obtained from this project have shown that hematite exhibits different modes of attrition, including both due to mechanical stresses and due to structural changes in the particles due to chemical reaction at high temperature. The test methodology has also proven effective in providing reactivity changes of the material with continued use, a property, which in addition to attrition, determines material life. Consumption/replacement cost due to attrition or loss of reactivity is a critical factor in the economic application of the chemical looping technology. This test method will allow rapid evaluation of a wide range of materials that are best suited for this technology. The most important anticipated public benefit of this project is the acceleration of the development of chemical looping technology for lowering greenhouse gas emissions from fossil fuel combustion.

  8. Possible central nervous system oxygen toxicity seizures among US recreational air or enriched air nitrox open circuit diving fatalities 2004-2013.

    PubMed

    Buzzacott, P; Denoble, P J

    2017-01-01

    The first diver certification programme for recreational 'enriched air nitrox' (EAN) diving was released in 1985. Concerns were expressed that many EAN divers might suffer central nervous system (CNS) oxygen toxicity seizures and drown. US fatalities on open-circuit scuba occurring between 2004-2013, where the breathing gas was either air or EAN, were identified. Causes of death and preceding circumstances were examined by a medical examiner experienced in diving autopsies. Case notes were searched for witnessed seizures at elevated partial pressures of oxygen. The dataset comprised 344 air divers (86%) and 55 divers breathing EAN (14%). EAN divers' fatal dives were deeper than air divers' (28 msw vs 18 msw, p < 0.0001). Despite this, of the 249 cases where a cause of death was established, only three EAN divers were considered to have possibly died following CNS oxygen toxicity seizures at depth (ppO2 132, 142 and 193 kPa). The analysis of recreational diving fatalities in the US over 10 years found just one death likely from CNS oxygen toxicity among EAN divers. A further two possible, although unlikely, cases were also found. Fears of commonplace CNS oxygen toxicity seizures while EAN diving have not apparently been realized.

  9. Burning of solids in oxygen-rich environments in normal and reduced gravity. [combustion of cellulose acetates

    NASA Technical Reports Server (NTRS)

    Andracchio, C. R.; Cochran, T. H.

    1974-01-01

    An experimental program was conducted to investigate the combustion characteristics of solids burning in a weightless environment. The combustion characteristics of thin cellulose acetate material were obtained from specimens burned in supercritical as well as in low pressure oxygen atmospheres. Flame spread rates were measured and found to depend on material thickness and pressure in both normal gravity (1-g) and reduced gravity (0-g). A gravity effect on the burning process was also observed; the ratio of 1-g to 0-g flame spread rate becomes larger with increasing material thickness. Qualitative results on the combustion characteristics of metal screens (stainless steel, Inconel, copper, and aluminum) burning in supercritical oxygen and normal gravity are also presented. Stainless steel (300 sq mesh) was successfully ignited in reduced gravity; no apparent difference in the flame spread pattern was observed between 1-g and 0-g.

  10. Measurement and modelling of oxygenated organic compounds from smoldering combustion of biomass

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    McKenzie, L.M.; Richards, G.N.

    Biomass fires emit a myriad of compounds, some of which are toxic and/or globally significant as photochemically reactive, tropospheric trace gases, greenhouse gases and precursors to stratospheric ozone-destroying radicals. 35 oxygenated organic compounds in condensed (-45{degrees}C) smoke from 29 bench scale fires of ponderosa pine sapwood, needles, bark, litter, duff, and humus have been identified and quantified. These fires ranged from flaming to low intensity smoldering. In addition, five low intensity fires of intact ponderosa pine forest floor (litter, duff, and humus) were carried out on a larger scale in a combustion chamber. The condensates were analyzed by gas chromatography/massmore » spectrometry and the gas phase was analyzed by gas chromatography/flame ionization detection. Acetic acid, vinyl acetate and acetol were major condensable emissions. The dependence of oxygenated organic emissions on fuel chemistry and combustion efficiency has been investigated, along with correlations between emissions. Molar emission ratios of individual compounds to CO have been calculated and used to estimate possible exposure levels for wildland firefighters.« less

  11. Methanol Droplet Combustion in Oxygen-Inert Environments in Microgravity

    NASA Technical Reports Server (NTRS)

    Nayagam, Vedha; Dietrich, Daniel L.; Hicks, Michael C.; Williams, Forman A.

    2013-01-01

    The Flame Extinguishment (FLEX) experiment that is currently underway in the Combustion Integrated Rack facility onboard the International Space Station is aimed at understanding the effects of inert diluents on the flammability of condensed phase fuels. To this end, droplets of various fuels, including alkanes and alcohols, are burned in a quiescent microgravity environment with varying amounts of oxygen and inert diluents to determine the limiting oxygen index (LOI) for these fuels. In this study we report experimental observations of methanol droplets burning in oxygen-nitrogen-carbon dioxide and oxygen-nitrogen-helium gas mixtures at 0.7 and 1 atmospheric pressures. The initial droplet size varied between approximately 1.5 mm and 4 mm to capture both diffusive extinction brought about by insufficient residence time at the flame and radiative extinction caused by excessive heat loss from the flame zone. The ambient oxygen concentration varied from a high value of 30% by volume to as low as 12%, approaching the limiting oxygen index for the fuel. The inert dilution by carbon dioxide and helium varied over a range of 0% to 70% by volume. In these experiments, both freely floated and tethered droplets were ignited using symmetrically opposed hot-wire igniters and the burning histories were recorded onboard using digital cameras, downlinked later to the ground for analysis. The digital images yielded droplet and flame diameters as functions of time and subsequently droplet burning rate, flame standoff ratio, and initial and extinction droplet diameters. Simplified theoretical models correlate the measured burning rate constant and the flame standoff ratio reasonably well. An activation energy asymptotic theory accounting for time-dependent water dissolution or evaporation from the droplet is shown to predict the measured diffusive extinction conditions well. The experiments also show that the limiting oxygen index for methanol in these diluent gases is around 12% to

  12. Extravehicular mobility unit subcritical liquid oxygen storage and supply system

    NASA Technical Reports Server (NTRS)

    Anderson, John; Martin, Timothy; Hodgson, ED

    1992-01-01

    The storage of life support oxygen in the Extravehicular Mobility Unit in the liquid state offers some advantages over the current method of storing the oxygen as a high pressure gas. Storage volume is reduced because of the increased density associated with liquid. The lower storage and operating pressures also reduce the potential for leakage or bursting of the storage tank. The potential for combustion resulting from adiabatic combustion of the gas within lines and components is substantially reduced. Design constraints on components are also relaxed due to the lower system pressures. A design study was performed to determine the requirements for a liquid storage system and prepare a conceptual design. The study involved four tasks. The first was to identify system operating requirements that influence or direct the design of the system. The second was to define candidate storage system concepts that could possibly satisfy the requirements. An evaluation and comparison of the candidate concepts was conducted in the third task. The fourth task was devoted to preparing a conceptual design of the recommended storage system and to evaluate concerns with integration of the concept into the EMU. The results are presented.

  13. High arsenic concentrations and enriched sulfur and oxygen isotopes in a fractured-bedrock ground-water system

    USGS Publications Warehouse

    Lipfert, G.; Sidle, W.C.; Reeve, A.S.; Ayuso, R.A.; Boyce, A.J.

    2007-01-01

    Ground water with high arsenic concentrations (up to 26.6????mol L- 1) has sulfate enriched in 34S and 18O in the fractured-bedrock, ground-water system of the Kelly's Cove watershed, Northport, Maine, USA. The ranges of sulfur and oxygen isotope values in aqueous sulfate, ??34S[SO4] and ??18O[SO4], at the Kelly's Cove watershed are + 3.4 to + 4.9??? and - 2.0 to + 6.7???, respectively. These isotope values are strikingly similar to those of the Goose River, Maine watershed which has ??34S[SO4] and ??18O[SO4] ranges of + 3.7 to + 4.6 ??? and - 2.6 to + 7.5???, respectively. In both systems, high arsenic concentrations occur with high ??34S[SO4] and ??18O[SO4] values, yet redox conditions and underlying rock types are quite different. The isotope values of sulfide minerals, ??34S[min], from four bedrock cores vary over short distances and range from - 5.1 to + 7.5???. The ??34S[SO4] values are controlled by the ??34S[min] values with minor input of atmospheric SO4. The much narrower range in ??34S[SO4] values than ??34S[min] values is probably due to sufficient ground-water mixing at a scale greater than the ??34S[min] variability. The ??34S[SO4] values are about 2??? higher than the average ??34S[min] value and fall within the range of ??34S[min] values, indicating only minor fractionation due to bacterial reduction of SO4. The highest ??18O[SO4] values were measured in the downgradient, confined, arsenic-rich ground water. High ??18O[SO4] values there cannot be due to aeration by atmospheric oxygen, but may arise from reoxidation of reduced SO4 products. The enrichment factors of ??18O in SO4 compared to H2O, + 7.2 to + 15.5???, in the Kelly's Cove ground water and the negligible 34S enrichment is very similar to those derived from experimental data of anaerobic sulfide oxidation in the presence of Mn and Fe oxides. Sea level at the Kelly's Cove watershed was approximately 80??m above present sea level about 13 000??years before present, imposing reducing

  14. Reduction behavior and kinetics of vanadium-titanium sinters under high potential oxygen enriched pulverized coal injection

    NASA Astrophysics Data System (ADS)

    Ma, Jin-fang; Wang, Guang-wei; Zhang, Jian-liang; Li, Xin-yu; Liu, Zheng-jian; Jiao, Ke-xin; Guo, Jian

    2017-05-01

    In this work, the reduction behavior of vanadium-titanium sinters was studied under five different sets of conditions of pulverized coal injection with oxygen enrichment. The modified random pore model was established to analyze the reduction kinetics. The results show that the reduction rate of sinters was accelerated by an increase of CO and H2 contents. Meanwhile, with the increase in CO and H2 contents, the increasing range of the medium reduction index (MRE) of sinters decreased. The increasing oxygen enrichment ratio played a diminishing role in improving the reduction behavior of the sinters. The reducing process kinetic parameters were solved using the modified random role model. The results indicated that, with increasing oxygen enrichment, the contents of CO and H2 in the reducing gas increased. The reduction activation energy of the sinters decreased to between 20.4 and 23.2 kJ/mol.

  15. Ames Hybrid Combustion Facility

    NASA Technical Reports Server (NTRS)

    Zilliac, Greg; Karabeyoglu, Mustafa A.; Cantwell, Brian; Hunt, Rusty; DeZilwa, Shane; Shoffstall, Mike; Soderman, Paul T.; Bencze, Daniel P. (Technical Monitor)

    2003-01-01

    The report summarizes the design, fabrication, safety features, environmental impact, and operation of the Ames Hybrid-Fuel Combustion Facility (HCF). The facility is used in conducting research into the scalability and combustion processes of advanced paraffin-based hybrid fuels for the purpose of assessing their applicability to practical rocket systems. The facility was designed to deliver gaseous oxygen at rates between 0.5 and 16.0 kg/sec to a combustion chamber operating at pressures ranging from 300 to 900. The required run times were of the order of 10 to 20 sec. The facility proved to be robust and reliable and has been used to generate a database of regression-rate measurements of paraffin at oxygen mass flux levels comparable to those of moderate-sized hybrid rocket motors.

  16. Combustion-gas recirculation system

    DOEpatents

    Baldwin, Darryl Dean

    2007-10-09

    A combustion-gas recirculation system has a mixing chamber with a mixing-chamber inlet and a mixing-chamber outlet. The combustion-gas recirculation system may further include a duct connected to the mixing-chamber inlet. Additionally, the combustion-gas recirculation system may include an open inlet channel with a solid outer wall. The open inlet channel may extend into the mixing chamber such that an end of the open inlet channel is disposed between the mixing-chamber inlet and the mixing-chamber outlet. Furthermore, air within the open inlet channel may be at a pressure near or below atmospheric pressure.

  17. Sorbent-based Oxygen Production for Energy Systems

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Sethi, Vijay

    Project DE-FE0024075 deals with the development of a moderate-temperature sorbent-based oxygen production technology. Sorbent-based oxygen production process utilizes oxygen-storage properties of Perovskites to (1) adsorb oxygen from air in a solid sorbent, and (2) release the adsorbed oxygen into a sweep gas such as CO 2 and/or steam for gasification systems or recycled flue gas for oxy-combustion systems. Pure oxygen can be produced by the use of vacuum instead of a sweep gas to affect the pressure swing. By developing more efficient and stable, higher sorption capacity, newer class of materials operating at moderate temperatures this process represents a majormore » advancement in air separation technology. Newly developed perovskite ceramic sorbent materials with order-disorder transition have a higher O 2 adsorption capacity, potentially 200 °C lower operating temperatures, and up to two orders of magnitude faster desorption rates than those used in earlier development efforts. The performance advancements afforded by the new materials lead to substantial savings in capital investment and operational costs. Cost of producing oxygen using sorbents could be as much as 26% lower than VPSA and about 13% lower than a large cryogenic air separation unit. Cost advantage against large cryogenic separation is limited because sorbent-based separation numbers up sorbent modules for achieving the larger capacity.« less

  18. Effect of administration of water enriched in O2 by injection or electrolysis on transcutaneous oxygen pressure in anesthetized pigs.

    PubMed

    Charton, Antoine; Péronnet, François; Doutreleau, Stephane; Lonsdorfer, Evelyne; Klein, Alexis; Jimenez, Liliana; Geny, Bernard; Diemunsch, Pierre; Richard, Ruddy

    2014-01-01

    Oral administration of oxygenated water has been shown to improve blood oxygenation and could be an alternate way for oxygen (O2) supply. In this experiment, tissue oxygenation was compared in anesthetized pigs receiving a placebo or water enriched in O2 by injection or a new electrolytic process. Forty-two pigs randomized in three groups received either mineral water as placebo or water enriched in O2 by injection or the electrolytic process (10 mL/kg in the stomach). Hemodynamic parameters, partial pressure of oxygen in the arterial blood (PaO2), skin blood flow, and tissue oxygenation (transcutaneous oxygen pressure, or TcPO2) were monitored during 90 minutes of general anesthesia. Absorption and tissue distribution of the three waters administered were assessed using dilution of deuterium oxide. Mean arterial pressure, heart rate, PaO2, arteriovenous oxygen difference, and water absorption from the gut were not significantly different among the three groups. The deuterium to protium ratio was also similar in the plasma, skin, and muscle at the end of the protocol. Skin blood flow decreased in the three groups. TcPO2 slowly decreased over the last 60 minutes of the experiment in the three groups, but when compared to the control group, the values remained significantly higher in animals that received the water enriched in O2 by electrolysis. In this protocol, water enriched in O2 by electrolysis lessened the decline of peripheral tissue oxygenation. This observation is compatible with the claim that the electrolytic process generates water clathrates which trap O2 and facilitate O2 diffusion along pressure gradients. Potential applications of O2-enriched water include an alternate method of oxygen supply.

  19. Effect of administration of water enriched in O2 by injection or electrolysis on transcutaneous oxygen pressure in anesthetized pigs

    PubMed Central

    Charton, Antoine; Péronnet, François; Doutreleau, Stephane; Lonsdorfer, Evelyne; Klein, Alexis; Jimenez, Liliana; Geny, Bernard; Diemunsch, Pierre; Richard, Ruddy

    2014-01-01

    Background Oral administration of oxygenated water has been shown to improve blood oxygenation and could be an alternate way for oxygen (O2) supply. In this experiment, tissue oxygenation was compared in anesthetized pigs receiving a placebo or water enriched in O2 by injection or a new electrolytic process. Methods Forty-two pigs randomized in three groups received either mineral water as placebo or water enriched in O2 by injection or the electrolytic process (10 mL/kg in the stomach). Hemodynamic parameters, partial pressure of oxygen in the arterial blood (PaO2), skin blood flow, and tissue oxygenation (transcutaneous oxygen pressure, or TcPO2) were monitored during 90 minutes of general anesthesia. Absorption and tissue distribution of the three waters administered were assessed using dilution of deuterium oxide. Results Mean arterial pressure, heart rate, PaO2, arteriovenous oxygen difference, and water absorption from the gut were not significantly different among the three groups. The deuterium to protium ratio was also similar in the plasma, skin, and muscle at the end of the protocol. Skin blood flow decreased in the three groups. TcPO2 slowly decreased over the last 60 minutes of the experiment in the three groups, but when compared to the control group, the values remained significantly higher in animals that received the water enriched in O2 by electrolysis. Conclusions In this protocol, water enriched in O2 by electrolysis lessened the decline of peripheral tissue oxygenation. This observation is compatible with the claim that the electrolytic process generates water clathrates which trap O2 and facilitate O2 diffusion along pressure gradients. Potential applications of O2-enriched water include an alternate method of oxygen supply. PMID:25210438

  20. Development of modified poly(perfluoropropyleneoxide) urethane systems for use in liquid oxygen and in enriched 100 percent oxygen atmosphere

    NASA Technical Reports Server (NTRS)

    Harrison, E. S.

    1973-01-01

    This program consisted of two separate though related phases. The initial phase was directed toward improving the mechanical and adhesive properties of the very highly fluorinated-polyurethane resin system derived from the hydroxyl-terminated polyperfluoropropylene oxide and 6-chloro-2,4,5-trifluoro-m-phenylene diisocyanate. Various new curing agents for this system were investigated, with the goal of providing a more thermally stable crosslink (cure) mechanism to provide wider applicability and fuller utilization of the outstanding oxygen resistance of the PFPO system. Complete resistance to liquid- and gaseous-oxygen impact at presures as high as 1035 N/sq cm were attained with the use of the PFPO resin castings. The second corollary phase was directed toward investigating the feasibility and optimization of the allophanate cured, urethane extended polymer derived from hydroxyl-terminated polyperfluoropropyleneoxide and 6-chloro-2,4,5-trifluoro-m-phenylene diisocyanate, as the adhesive system for use in a weld-bond configuration for liquid oxygen tankage. The synthesis and application procedures of the adhesive system to insure liquid oxygen compatibility (under 10 kg-m loading), and the development of procedures and techniques to provide high quality weld-bonded joint configurations were studied.

  1. Coal combustion system

    DOEpatents

    Wilkes, Colin; Mongia, Hukam C.; Tramm, Peter C.

    1988-01-01

    In a coal combustion system suitable for a gas turbine engine, pulverized coal is transported to a rich zone combustor and burned at an equivalence ratio exceeding 1 at a temperature above the slagging temperature of the coal so that combustible hot gas and molten slag issue from the rich zone combustor. A coolant screen of water stretches across a throat of a quench stage and cools the combustible gas and molten slag to below the slagging temperature of the coal so that the slag freezes and shatters into small pellets. The pelletized slag is separated from the combustible gas in a first inertia separator. Residual ash is separated from the combustible gas in a second inertia separator. The combustible gas is mixed with secondary air in a lean zone combustor and burned at an equivalence ratio of less than 1 to produce hot gas motive at temperature above the coal slagging temperature. The motive fluid is cooled in a dilution stage to an acceptable turbine inlet temperature before being transported to the turbine.

  2. NO.sub.x reduction method

    DOEpatents

    Sekar, Ramanujam R.; Hoppie, Lyle O.

    1996-01-01

    A method of reducing oxides of nitrogen (NO.sub.X) in the exhaust of an internal combustion engine includes producing oxygen enriched air and nitrogen enriched air by an oxygen enrichment device. The oxygen enriched air may be provided to the intake of the internal combustion engine for mixing with fuel. In order to reduce the amount of NO.sub.X in the exhaust of the internal combustion engine, the molecular nitrogen in the nitrogen enriched air produced by the oxygen enrichment device is subjected to a corona or arc discharge so as to create a plasma and as a result, atomic nitrogen. The resulting atomic nitrogen then is injected into the exhaust of the internal combustion engine causing the oxides of nitrogen in the exhaust to be reduced into nitrogen and oxygen. In one embodiment of the present invention, the oxygen enrichment device that produces both the oxygen and nitrogen enriched air can include a selectively permeable membrane.

  3. Constraining the Final Fates of Massive Stars by Oxygen and Iron Enrichment History in the Galaxy

    NASA Astrophysics Data System (ADS)

    Suzuki, Akihiro; Maeda, Keiichi

    2018-01-01

    Recent observational studies of core-collapse supernovae suggest that only stars with zero-age main-sequence masses smaller than 16–18 {M}ȯ explode when they are red supergiants, producing Type IIP supernovae. This may imply that more massive stars produce other types of supernovae or they simply collapse to black holes without giving rise to bright supernovae. This failed supernova hypothesis can lead to significantly inefficient oxygen production because oxygen abundantly produced in inner layers of massive stars with zero-age main-sequence masses around 20–30 {M}ȯ might not be ejected into the surrounding interstellar space. We first assume an unspecified population of oxygen injection events related to massive stars and obtain a model-independent constraint on how much oxygen should be released in a single event and how frequently such events should happen. We further carry out one-box galactic chemical enrichment calculations with different mass ranges of massive stars exploding as core-collapse supernovae. Our results suggest that the model assuming that all massive stars with 9–100 {M}ȯ explode as core-collapse supernovae is still most appropriate in explaining the solar abundances of oxygen and iron and their enrichment history in the Galaxy. The oxygen mass in the Galaxy is not explained when assuming that only massive stars with zero-age main-sequence masses in the range of 9–17 {M}ȯ contribute to the galactic oxygen enrichment. This finding implies that a good fraction of stars more massive than 17 {M}ȯ should eject their oxygen layers in either supernova explosions or some other mass-loss processes.

  4. Combustibles sensor

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Pebler, A.R.

    1980-02-26

    A gaseous mixture of oxygen and fuel (Combustibles) is supplied to first and second electrodes disposed on opposite surfaces of an oxygen ion conductive solid electrolyte member wherein the electrodes are composed of different materials each exhibiting a different catalytic action on the gaseous mixture at a given temperature. The difference in oxygen potentials established at the respective electrodes as a result of the dissimilar catalytic action produces oxygen ion conductivity in the solid electrolyte cell which produces an electrical signal the magnitude of which is indicative of the combustible present in the mixture, I.E., methane, hydrogen, carbon monoxide, etc.

  5. Fabrication and processing of next-generation oxygen carrier materials for chemical looping combustion

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Nadarajah, Arunan

    Among numerous methods of controlling the global warming effect, Chemical Looping Combustion is known to be the most viable option currently. A key factor to a successful chemical looping process is the presence of highly effective oxygen carriers that enable fuel combustion by going through oxidation and reduction in the presence of air and fuel respectively. In this study, CaMnO 3-δ was used as the base material and doped on the A-site (Sr or La) and B-site (Fe, Ti, Zn and Al) by 10 mol % of dopants. Solid state reaction followed by mechanical extrusion (optimized paste formula) was usedmore » as the preparation method A series of novel doped perovskite-type oxygen carrier particles (Ca xLa (Or Sa) 1-x Mn 1-yByO 3-δ (B-site = Fe, Ti, Al, or Zr)) were synthesized by the proposed extrusion formula. The produced samples were characterized with XRD, SEM, BET and TGA techniques. According to the results obtained from TGA analysis, the oxygen capacity of the samples ranged between 1.2 for CLMZ and 1.75 for CSMF. Reactivity and oxygen uncoupling behaviors of the prepared samples were also evaluated using a fluidized bed chemical looping reactor using methane as the fuel at four different temperatures (800, 850, 900, 950 °C). All of the oxygen carriers showed oxygen uncoupling behavior and they were able to capture and release oxygen. Mass-based conversion of the perovskites was calculated and temperature increase proved to increase the mass-based conversion rate in all of the samples under study. Gas yield was calculated at 950 °C as well, and results showed that CLMZ, CM and CSMF showed 100% gas yields and CLMF and CSMZ showed approximately 85% yield in fluidized bed reactor, which is a high and acceptable quantity. Based on extended reactor tests the modified calcium manganese perovskite structures (CSMF) can be a good candidate for future pilot tests.« less

  6. ENVIRONMENTAL TECHNOLOGY VERIFICATION REPORT, NOX CONTROL TECHNOLOGIES, CATALYTICA COMBUSTION SYSTEMS, INC., XONON FLAMELESS COMBUSTION SYSTEM

    EPA Science Inventory

    The Environmental Technology Verification report discusses the technology and performance of the Xonon Cool Combustion System manufactured by Catalytica Energy Systems, Inc., formerly Catalytica Combustion Systems, Inc., to control NOx emissions from gas turbines that operate wit...

  7. High-pressure calorimeter chamber tests for liquid oxygen/kerosene (LOX/RP-1) rocket combustion

    NASA Technical Reports Server (NTRS)

    Masters, Philip A.; Armstrong, Elizabeth S.; Price, Harold G.

    1988-01-01

    An experimental program was conducted to investigate the rocket combustion and heat transfer characteristics of liquid oxygen/kerosene (LOX/RP-1) mixtures at high chamber pressures. Two water-cooled calorimeter chambers of different combustion lengths were tested using 37- and 61-element oxidizer-fuel-oxidizer triplet injectors. The tests were conducted at nominal chamber pressures of 4.1, 8.3, and 13.8 MPa abs (600, 1200, and 2000 psia). Heat flux Q/A data were obtained for the entire calorimeter length for oxygen/fuel mixture ratios of 1.8 to 3.3. Test data at 4.1 MPa abs compared favorably with previous test data from another source. Using an injector with a fuel-rich outer zone reduced the throat heat flux by 47 percent with only a 4.5 percent reduction in the characteristic exhaust velocity efficiency C* sub eff. The throat heat transfer coefficient was reduced approximately 40 percent because of carbon deposits on the chamber wall.

  8. Dilute Oxygen Combustion Phase IV Final Report

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Riley, M.F.

    2003-04-30

    Novel furnace designs based on Dilute Oxygen Combustion (DOC) technology were developed under subcontract by Techint Technologies, Coraopolis, PA, to fully exploit the energy and environmental capabilities of DOC technology and to provide a competitive offering for new furnace construction opportunities. Capital cost, fuel, oxygen and utility costs, NOx emissions, oxide scaling performance, and maintenance requirements were compared for five DOC-based designs and three conventional air5-fired designs using a 10-year net present value calculation. A furnace direct completely with DOC burners offers low capital cost, low fuel rate, and minimal NOx emissions. However, these benefits do not offset the costmore » of oxygen and a full DOC-fired furnace is projected to cost $1.30 per ton more to operate than a conventional air-fired furnace. The incremental cost of the improved NOx performance is roughly $6/lb NOx, compared with an estimated $3/lb. NOx for equ8pping a conventional furnace with selective catalytic reduction (SCCR) technology. A furnace fired with DOC burners in the heating zone and ambient temperature (cold) air-fired burners in the soak zone offers low capital cost with less oxygen consumption. However, the improvement in fuel rate is not as great as the full DOC-fired design, and the DOC-cold soak design is also projected to cost $1.30 per ton more to operate than a conventional air-fired furnace. The NOx improvement with the DOC-cold soak design is also not as great as the full DOC fired design, and the incremental cost of the improved NOx performance is nearly $9/lb NOx. These results indicate that a DOC-based furnace design will not be generally competitive with conventional technology for new furnace construction under current market conditions. Fuel prices of $7/MMBtu or oxygen prices of $23/ton are needed to make the DOC furnace economics favorable. Niche applications may exist, particularly where access to capital is limited or floor space

  9. Effects of argon enriched low-oxygen atmospheres and of high-oxygen atmospheres on the kinetics of polyphenoloxidase (PPO).

    PubMed

    O'Beirne, David; Murphy, Eileen; Ni Eidhin, Deirdre

    2011-01-01

    The reported benefits of enrichment of air atmospheres with argon or oxygen for control of enzymatic browning were investigated by determining the effects of these atmospheres on PPO kinetics. Kinetics of purified apple PPO and a commercially available mushroom PPO were studied in an in vitro model system. Enrichment with argon produced greater inhibitory effects than the current industry practice of enrichment with nitrogen. Km(app) values (mM) for apple PPO in 3%O(2)/97%Ar, 3%O(2)/97%N(2), and air, were 133, 87, and 48, respectively. The data indicate that inhibition by both gases is competitive, and also support the hypothesis that the greater inhibitory effect of argon was proportional to the size of the Van der Waals radius of argon against nitrogen (1.91 Å against 1.54 Å). Much smaller inhibitory effects were observed in the presence of 80% O(2) (Km(app) 57 mM), and the nature of this inhibition was less clear. The results suggest that the benefits of argon enrichment may be relatively small, and may require critical enzyme, substrate, and gas levels to be successful. However, these benefits may be exploitable commercially in some fresh-cut products, and may allow less anoxic atmospheres to be used. Practical Application: Control of enzymatic browning without sulfites continues to be a challenge in some fresh-cut products. While sporadic benefits of these atmospheres in control of enzymatic browning have been reported, results have been inconsistent in commercial practice. The results suggest that the benefits of argon enrichment may be relatively small, and may require critical enzyme, substrate, and gas levels to be successful. However, these benefits may be exploitable commercially in some fresh-cut products, and allow less anoxic atmospheres to be used.

  10. Analysis of the laser ignition of methane/oxygen mixtures in a sub-scale rocket combustion chamber

    NASA Astrophysics Data System (ADS)

    Wohlhüter, Michael; Zhukov, Victor P.; Sender, Joachim; Schlechtriem, Stefan

    2017-06-01

    The laser ignition of methane/oxygen mixtures in a sub-scale rocket combustion chamber has been investigated numerically and experimentally. The ignition test case used in the present paper was generated during the In-Space Propulsion project (ISP-1), a project focused on the operation of propulsion systems in space, the handling of long idle periods between operations, and multiple reignitions under space conditions. Regarding the definition of the numerical simulation and the suitable domain for the current model, 2D and 3D simulations have been performed. Analysis shows that the usage of a 2D geometry is not suitable for this type of simulation, as the reduction of the geometry to a 2D domain significantly changes the conditions at the time of ignition and subsequently the flame development. The comparison of the numerical and experimental results shows a strong discrepancy in the pressure evolution and the combustion chamber pressure peak following the laser spark. The detailed analysis of the optical Schlieren and OH data leads to the conclusion that the pressure measurement system was not able to capture the strong pressure increase and the peak value in the combustion chamber during ignition. Although the timing in flame development following the laser spark is not captured appropriately, the 3D simulations reproduce the general ignition phenomena observed in the optical measurement systems, such as pressure evolution and injector flow characteristics.

  11. The oxycoal process with cryogenic oxygen supply.

    PubMed

    Kather, Alfons; Scheffknecht, Günter

    2009-09-01

    Due to its large reserves, coal is expected to continue to play an important role in the future. However, specific and absolute CO2 emissions are among the highest when burning coal for power generation. Therefore, the capture of CO2 from power plants may contribute significantly in reducing global CO2 emissions. This review deals with the oxyfuel process, where pure oxygen is used for burning coal, resulting in a flue gas with high CO2 concentrations. After further conditioning, the highly concentrated CO2 is compressed and transported in the liquid state to, for example, geological storages. The enormous oxygen demand is generated in an air-separation unit by a cryogenic process, which is the only available state-of-the-art technology. The generation of oxygen and the purification and liquefaction of the CO2-enriched flue gas consumes significant auxiliary power. Therefore, the overall net efficiency is expected to be lowered by 8 to 12 percentage points, corresponding to a 21 to 36% increase in fuel consumption. Oxygen combustion is associated with higher temperatures compared with conventional air combustion. Both the fuel properties as well as limitations of steam and metal temperatures of the various heat exchanger sections of the steam generator require a moderation of the temperatures during combustion and in the subsequent heat-transfer sections. This is done by means of flue gas recirculation. The interdependencies among fuel properties, the amount and the temperature of the recycled flue gas, and the resulting oxygen concentration in the combustion atmosphere are investigated. Expected effects of the modified flue gas composition in comparison with the air-fired case are studied theoretically and experimentally. The different atmosphere resulting from oxygen-fired combustion gives rise to various questions related to firing, in particular, with regard to the combustion mechanism, pollutant reduction, the risk of corrosion, and the properties of the fly

  12. The oxycoal process with cryogenic oxygen supply

    NASA Astrophysics Data System (ADS)

    Kather, Alfons; Scheffknecht, Günter

    2009-09-01

    Due to its large reserves, coal is expected to continue to play an important role in the future. However, specific and absolute CO2 emissions are among the highest when burning coal for power generation. Therefore, the capture of CO2 from power plants may contribute significantly in reducing global CO2 emissions. This review deals with the oxyfuel process, where pure oxygen is used for burning coal, resulting in a flue gas with high CO2 concentrations. After further conditioning, the highly concentrated CO2 is compressed and transported in the liquid state to, for example, geological storages. The enormous oxygen demand is generated in an air-separation unit by a cryogenic process, which is the only available state-of-the-art technology. The generation of oxygen and the purification and liquefaction of the CO2-enriched flue gas consumes significant auxiliary power. Therefore, the overall net efficiency is expected to be lowered by 8 to 12 percentage points, corresponding to a 21 to 36% increase in fuel consumption. Oxygen combustion is associated with higher temperatures compared with conventional air combustion. Both the fuel properties as well as limitations of steam and metal temperatures of the various heat exchanger sections of the steam generator require a moderation of the temperatures during combustion and in the subsequent heat-transfer sections. This is done by means of flue gas recirculation. The interdependencies among fuel properties, the amount and the temperature of the recycled flue gas, and the resulting oxygen concentration in the combustion atmosphere are investigated. Expected effects of the modified flue gas composition in comparison with the air-fired case are studied theoretically and experimentally. The different atmosphere resulting from oxygen-fired combustion gives rise to various questions related to firing, in particular, with regard to the combustion mechanism, pollutant reduction, the risk of corrosion, and the properties of the fly

  13. System approach to the analysis of an integrated oxy-fuel combustion power plant

    NASA Astrophysics Data System (ADS)

    Ziębik, Andrzej; Gładysz, Paweł

    2014-09-01

    Oxy-fuel combustion (OFC) belongs to one of the three commonly known clean coal technologies for power generation sector and other industry sectors responsible for CO2 emissions (e.g., steel or cement production). The OFC capture technology is based on using high-purity oxygen in the combustion process instead of atmospheric air. Therefore flue gases have a high concentration of CO2. Due to the limited adiabatic temperature of combustion some part of CO2 must be recycled to the boiler in order to maintain a proper flame temperature. An integrated oxy-fuel combustion power plant constitutes a system consisting of the following technological modules: boiler, steam cycle, air separation unit, cooling water and water treatment system, flue gas quality control system and CO2 processing unit. Due to the interconnections between technological modules, energy, exergy and ecological analyses require a system approach. The paper present the system approach based on the `input-output' method to the analysis of the: direct energy and material consumption, cumulative energy and exergy consumption, system (local and cumulative) exergy losses, and thermoecological cost. Other measures like cumulative degree of perfection or index of sustainable development are also proposed. The paper presents a complex example of the system analysis (from direct energy consumption to thermoecological cost) of an advanced integrated OFC power plant.

  14. Carbon and oxygen isotopic composition of coal and carbon dioxide derived from laboratory coal combustion: A preliminary study

    USGS Publications Warehouse

    Warwick, Peter D.; Ruppert, Leslie F.

    2016-01-01

    The concentration of carbon dioxide (CO2) in the atmosphere has dramatically increased from the start of the industrial revolution in the mid-1700s to present levels exceeding 400 ppm. Carbon dioxide derived from fossil fuel combustion is a greenhouse gas and a major contributor to on-going climate change. Carbon and oxygen stable isotope geochemistry is a useful tool to help model and predict the contributions of anthropogenic sources of CO2 in the global carbon cycle. Surprisingly few studies have addressed the carbon and oxygen isotopic composition of CO2 derived from coal combustion. The goal of this study is to document the relationships between the carbon and oxygen isotope signatures of coal and signatures of the CO2 produced from laboratory coal combustion in atmospheric conditions.Six coal samples were selected that represent various geologic ages (Carboniferous to Tertiary) and coal ranks (lignite to bituminous). Duplicate splits of the six coal samples were ignited and partially combusted in the laboratory at atmospheric conditions. The resulting coal-combustion gases were collected and the molecular composition of the collected gases and isotopic analyses of δ13C of CO2, δ13C of CH4, and δ18O of CO2 were analysed by a commercial laboratory. Splits (~ 1 g) of the un-combusted dried ground coal samples were analyzed for δ13C and δ18O by the U.S. Geological Survey Reston Stable Isotope Laboratory.The major findings of this preliminary work indicate that the isotopic signatures of δ13C (relative to the Vienna Pee Dee Belemnite scale, VPDB) of CO2 resulting from coal combustion are similar to the δ13CVPDB signature of the bulk coal (− 28.46 to − 23.86 ‰) and are not similar to atmospheric δ13CVPDB of CO2 (~ − 8 ‰, see http://www.esrl.noaa.gov/gmd/outreach/isotopes/c13tellsus.html). The δ18O values of bulk coal are strongly correlated to the coal dry ash yields and appear to have little or no influence on the δ18O values of CO2

  15. Oxide Protective Coats for Ir/Re Rocket Combustion Chambers

    NASA Technical Reports Server (NTRS)

    Fortini, Arthur; Tuffias, Robert H.

    2003-01-01

    An improved material system has been developed for rocket engine combustion chambers for burning oxygen/ hydrogen mixtures or novel monopropellants, which are highly oxidizing at operating temperatures. The baseline for developing the improved material system is a prior iridium/rhenium system for chambers burning nitrogen tetroxide/monomethyl hydrazine mixtures, which are less oxidizing. The baseline combustion chamber comprises an outer layer of rhenium that provides structural support, plus an inner layer of iridium that acts as a barrier to oxidation of the rhenium. In the improved material system, the layer of iridium is thin and is coated with a thermal fatigue-resistant refractory oxide (specifically, hafnium oxide) that serves partly as a thermal barrier to decrease the temperature and thus the rate of oxidation of the rhenium. The oxide layer also acts as a barrier against the transport of oxidizing species to the surface of the iridium. Tests in which various oxygen/hydrogen mixtures were burned in iridium/rhenium combustion chambers lined with hafnium oxide showed that the operational lifetimes of combustion chambers of the improved material system are an order of magnitude greater than those of the baseline combustion chambers.

  16. An Improved Approach for Analyzing the Oxygen Compatibility of Solvents and other Oxygen-Flammable Materials for Use in Oxygen Systems

    NASA Technical Reports Server (NTRS)

    Harper, Susan A.; Juarez, Alfredo; Peralta, Stephen F.; Stoltzfus, Joel; Arpin, Christina Pina; Beeson, Harold D.

    2016-01-01

    Solvents used to clean oxygen system components must be assessed for oxygen compatibility, as incompatible residue or fluid inadvertently left behind within an oxygen system can pose a flammability risk. The most recent approach focused on solvent ignition susceptibility to assess the flammability risk associated with these materials. Previous evaluations included Ambient Pressure Liquid Oxygen (LOX) Mechanical Impact Testing (ASTM G86) and Autogenous Ignition Temperature (AIT) Testing (ASTM G72). The goal in this approach was to identify a solvent material that was not flammable in oxygen. As environmental policies restrict the available options of acceptable solvents, it has proven difficult to identify one that is not flammable in oxygen. A more rigorous oxygen compatibility approach is needed in an effort to select a new solvent for NASA applications. NASA White Sands Test Facility proposed an approach that acknowledges oxygen flammability, yet selects solvent materials based on their relative oxygen compatibility ranking, similar to that described in ASTM G63-99. Solvents are selected based on their ranking with respect to minimal ignition susceptibility, damage and propagation potential, as well as their relative ranking when compared with other solvent materials that are successfully used in oxygen systems. Test methods used in this approach included ASTM G86 (Ambient Pressure LOX Mechanical Impact Testing and Pressurized Gaseous Oxygen (GOX) Mechanical Impact Testing), ASTM G72 (AIT Testing), and ASTM D240 (Heat of Combustion (HOC) Testing). Only four solvents were tested through the full battery of tests for evaluation of oxygen compatibility: AK-225G as a baseline comparison, Solstice PF, L-14780, and Vertrel MCA. Baseline solvent AK-225G exhibited the lowest HOC and highest AIT of solvents tested. Nonetheless, Solstice PF, L-14780, and Vertrel MCA HOCs all fell well within the range of properties that are associated with proven oxygen system materials

  17. Analytical chemical kinetic investigation of the effects of oxygen, hydrogen, and hydroxyl radicals on hydrogen-air combustion

    NASA Technical Reports Server (NTRS)

    Carson, G. T., Jr.

    1974-01-01

    Quantitative values were computed which show the effects of the presence of small amounts of oxygen, hydrogen, and hydroxyl radicals on the finite-rate chemical kinetics of premixed hydrogen-air mixtures undergoing isobaric autoignition and combustion. The free radicals were considered to be initially present in hydrogen-air mixtures at equivalence ratios of 0.2, 0.6, 1.0, and 1.2. Initial mixture temperatures were 1100 K, 1200 K, and 1500 K, and pressures were 0.5, 1.0, 2.0, and 4.0 atm. Of the radicals investigated, atomic oxygen was found to be the most effective for reducing induction time, defined as the time to 5 percent of the total combustion temperature rise. The reaction time, the time between 5 percent and 95 percent of the temperature rise, is not decreased by the presence of free radicals in the initial hydrogen-air mixture. Fuel additives which yield free radicals might be used to effect a compact supersonic combustor design for efficient operation in an otherwise reaction-limited combustion regime.

  18. Metal ferrite oxygen carriers for chemical looping combustion of solid fuels

    DOEpatents

    Siriwardane, Ranjani V.; Fan, Yueying

    2017-01-31

    The disclosure provides a metal ferrite oxygen carrier for the chemical looping combustion of solid carbonaceous fuels, such as coal, coke, coal and biomass char, and the like. The metal ferrite oxygen carrier comprises MFe.sub.xO.sub.y on an inert support, where MFe.sub.xO.sub.y is a chemical composition and M is one of Mg, Ca, Sr, Ba, Co, Mn, and combinations thereof. For example, MFe.sub.xO.sub.y may be one of MgFe.sub.2O.sub.4, CaFe.sub.2O.sub.4, SrFe.sub.2O.sub.4, BaFe.sub.2O.sub.4, CoFe.sub.2O.sub.4, MnFeO.sub.3, and combinations thereof. The MFe.sub.xO.sub.y is supported on an inert support. The inert support disperses the MFe.sub.xO.sub.y oxides to avoid agglomeration and improve performance stability. In an embodiment, the inert support comprises from about 5 wt. % to about 60 wt. % of the metal ferrite oxygen carrier and the MFe.sub.xO.sub.y comprises at least 30 wt. % of the metal ferrite oxygen carrier. The metal ferrite oxygen carriers disclosed display improved reduction rates over Fe.sub.2O.sub.3, and improved oxidation rates over CuO.

  19. Identification of combustion intermediates in low-pressure premixed pyridine/oxygen/argon flames.

    PubMed

    Tian, Zhenyu; Li, Yuyang; Zhang, Taichang; Zhu, Aiguo; Qi, Fei

    2008-12-25

    Combustion intermediates of two low-pressure premixed pyridine/oxygen flames with respective equivalence ratios of 0.56 (C/O/N = 1:4.83:0.20) and 2.10 (C/O/N = 1:1.29:0.20) have been identified with tunable synchrotron vacuum ultraviolet (VUV) photoionization and molecular-beam mass spectrometry techniques. About 80 intermediates in the rich flame and 60 intermediates in the lean flame, including nitrogenous, oxygenated, and hydrocarbon intermediates, have been identified by measurements of photoionization mass spectra and photoionization efficiency spectra. Some radicals and new nitrogenous intermediates are identified in the present work. The experimental results are useful for studying the conversion of volatile nitrogen compounds and understanding the formation mechanism of NO(x) in flames of nitrogenous fuels.

  20. Laser Schlieren and ultraviolet diagnostics of rocket combustion

    NASA Technical Reports Server (NTRS)

    Fisher, S. C.

    1985-01-01

    A low pressure oxygen/hydrogen turbine drive combustor hot-fire test series was conducted on the Turbine Drive Combustor Technology Program. The first objective was to gather data on an axisymmetric combustion system to support anchoring of a new combustion/fluid dynamics computer code under development on the same contract. The second objective was to gain insight into low mixture ratio combustion characteristics of coaxial injector elements.

  1. Effect of oxygen atoms dissociated by non-equilibrium plasma on flame of methane oxygen and argon pre-mixture gas

    NASA Astrophysics Data System (ADS)

    Akashi, Haruaki; Yoshinaga, Tomokazu; Sasaki, Koichi

    2014-10-01

    For more efficient way of combustion, plasma-assisted combustion has been investigated by many researchers. But it is very difficult to clarify the effect of plasma even on the flame of methane. Because there are many complex chemical reactions in combustion system. Sasaki et al. has reported that the flame length of methane and air premixed burner shortened by irradiating microwave power. They also measured emission from Second Positive Band System of nitrogen during the irradiation. The emission indicates existence of high energy electrons which are accelerated by the microwave. The high energy electrons also dissociate oxygen molecules easily and oxygen atom would have some effects on the flame. But the dissociation ratio of oxygen molecules by the non-equilibrium plasma is significantly low, compared to that in the combustion reaction. To clarify the effect of dissociated oxygen atoms on the flame, dependence of dissociation ratio of oxygen on the flame has been examined using CHEMKIN. It is found that in the case of low dissociation ratio of 10-6, the ignition of the flame becomes slightly earlier. It is also found that in the case of high dissociation ratio of 10-3, the ignition time becomes significantly earlier by almost half. This work was supported by KAKENHI (22340170).

  2. Combustion engine system

    NASA Technical Reports Server (NTRS)

    Houseman, John (Inventor); Voecks, Gerald E. (Inventor)

    1986-01-01

    A flow through catalytic reactor which selectively catalytically decomposes methanol into a soot free hydrogen rich product gas utilizing engine exhaust at temperatures of 200 to 650 C to provide the heat for vaporizing and decomposing the methanol is described. The reactor is combined with either a spark ignited or compression ignited internal combustion engine or a gas turbine to provide a combustion engine system. The system may be fueled entirely by the hydrogen rich gas produced in the methanol decomposition reactor or the system may be operated on mixed fuels for transient power gain and for cold start of the engine system. The reactor includes a decomposition zone formed by a plurality of elongated cylinders which contain a body of vapor permeable, methanol decomposition catalyst preferably a shift catalyst such as copper-zinc.

  3. Combustion-wave ignition for rocket engines

    NASA Technical Reports Server (NTRS)

    Liou, Larry C.

    1992-01-01

    The combustion wave ignition concept was experimentally studied in order to verify its suitability for application in baffled sections of a large booster engine combustion chamber. Gaseous oxygen/gaseous methane (GOX/GH4) and gaseous oxygen/gaseous hydrogen (GOX/GH2) propellant combinations were evaluated in a subscale combustion wave ignition system. The system included four element tubes capable of carrying ignition energy simultaneously to four locations, simulating four baffled sections. Also, direct ignition of a simulated Main Combustion Chamber (MCC) was performed. Tests were conducted over a range of mixture ratios and tube geometries. Ignition was consistently attained over a wide range of mixture ratios. And at every ignition, the flame propagated through all four element tubes. For GOX/GH4, the ignition system ignited the MCC flow at mixture ratios from 2 to 10 and for GOX/GH2 the ratios is from 2 to 13. The ignition timing was found to be rapid and uniform. The total ignition delay when using the MCC was under 11 ms, with the tube-to-tube, as well as the run-to-run, variation under 1 ms. Tube geometries were found to have negligible effect on the ignition outcome and timing.

  4. Method and system for the removal of oxides of nitrogen and sulfur from combustion processes

    DOEpatents

    Walsh, John V.

    1987-12-15

    A process for removing oxide contaminants from combustion gas, and employing a solid electrolyte reactor, includes: (a) flowing the combustion gas into a zone containing a solid electrolyte and applying a voltage and at elevated temperature to thereby separate oxygen via the solid electrolyte, (b) removing oxygen from that zone in a first stream and removing hot effluent gas from that zone in a second stream, the effluent gas containing contaminant, (c) and pre-heating the combustion gas flowing to that zone by passing it in heat exchange relation with the hot effluent gas.

  5. H2-O2 combustion powered steam-MHD central power systems

    NASA Technical Reports Server (NTRS)

    Seikel, G. R.; Smith, J. M.; Nichols, L. D.

    1974-01-01

    Estimates are made for both the performance and the power costs of H2-O2 combustion powered steam-MHD central power systems. Hydrogen gas is assumed to be transmitted by pipe from a remote coal gasifier into the city and converted to electricity in a steam MHD plant having an integral gaseous oxygen plant. These steam MHD systems appear to offer an attractive alternative to both in-city clean fueled conventional steam power plants and to remote coal fired power plants with underground electric transmission into the city.

  6. Combustor nozzle for a fuel-flexible combustion system

    DOEpatents

    Haynes, Joel Meier [Niskayuna, NY; Mosbacher, David Matthew [Cohoes, NY; Janssen, Jonathan Sebastian [Troy, NY; Iyer, Venkatraman Ananthakrishnan [Mason, OH

    2011-03-22

    A combustor nozzle is provided. The combustor nozzle includes a first fuel system configured to introduce a syngas fuel into a combustion chamber to enable lean premixed combustion within the combustion chamber and a second fuel system configured to introduce the syngas fuel, or a hydrocarbon fuel, or diluents, or combinations thereof into the combustion chamber to enable diffusion combustion within the combustion chamber.

  7. Technology evaluation report: SITE (Superfund Innovative Technology Evaluation) program demonstration test. The American Combustion Pyretron Thermal Destruction System at the US EPA's (Environmental Protection Agency's) combustion research facility

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Waterland, L.; Lee, J.W.

    1989-04-01

    A series of demonstration tests of the American Combustion, Inc., Thermal Destruction System was performed under the SITE program. This oxygen-enhanced combustion system was retrofit to the rotary-kiln incinerator at EPA's Combustion Research Facility. The system's performance was tested firing contaminated soil from the Stringfellow Superfund Site, both alone and mixed with a coal tar waste (KO87). Comparative performance with conventional incinerator operation was also tested. Compliance with the incinerator performance standards of 99.99% principal organic hazardous constituents (POHC) destruction and removal efficiency and particulate emissions of less than 180 mg/dscm at 7% O2 was measured for all tests. Themore » Pyretron system was capable of in-compliance performance at double the mixed waste feedrate and at a 60% increase in batch waste charge mass than possible with conventional incineration. Scrubber blowdown and kiln ash contained no detectable levels of any of the POHCs chosen.« less

  8. Carbon monoxide and oxygen combustion experiments: A demonstration of Mars in situ propellants

    NASA Technical Reports Server (NTRS)

    Linne, Diane L.

    1991-01-01

    The feasibility of using carbon monoxide and oxygen as rocket propellants was examined both experimentally and theoretically. The steady-state combustion of carbon monoxide and oxygen was demonstrated for the first time in a subscale rocket engine. Measurements of experimental characteristic velocity, vacuum specific impulse, and thrust coefficient efficiency were obtained over a mixture ratio range of 0.30 to 2.0 and a chamber pressures of 1070 and 530 kPa. The theoretical performance of the propellant combination was studied parametrically over the same mixture ratio range. In addition to one dimensional ideal performance predictions, various performance reduction mechanisms were also modeled, including finite-rate kinetic reactions, two-dimensional divergence effects and viscous boundary layer effects.

  9. Lunar and Planetary Science XXXV: Special Session: Oxygen in the Solar System, II

    NASA Technical Reports Server (NTRS)

    2004-01-01

    The Special Session: Oxygen in the Solar System, II, included the following reports:Evolution of Oxygen Isotopes in the Solar Nebula; Disequilibrium Melting of Refractory Inclusions: A Mechanism for High-Temperature Oxygen; Isotope Exchange in the Solar Nebula; Oxygen Isotopic Compositions of the Al-rich Chondrules in the CR Carbonaceous Chondrites: Evidence for a Genetic Link to Ca-Al-rich Inclusions and for Oxygen Isotope Exchange During Chondrule Melting; Nebular Formation of Fayalitic Olivine: Ineffectiveness of Dust Enrichment; Water in Terrestrial Planets: Always an Oxidant?; Oxygen Barometry of Basaltic Glasses Based on Vanadium Valence Determination Using Synchrotron MicroXANES; A New Oxygen Barometer for Solar System Basaltic Glasses Based on Vanadium Valence; The Relationship Between Clinopyroxene Fe3+ Content and Oxygen Fugacity ; and Olivine-Silicate Melt Partitioning of Iridium.

  10. A conceptual design of catalytic gasification fuel cell hybrid power plant with oxygen transfer membrane

    NASA Astrophysics Data System (ADS)

    Shi, Wangying; Han, Minfang

    2017-09-01

    A hybrid power generation system integrating catalytic gasification, solid oxide fuel cell (SOFC), oxygen transfer membrane (OTM) and gas turbine (GT) is established and system energy analysis is performed. In this work, the catalytic gasifier uses steam, recycled anode off-gas and pure oxygen from OTM system to gasify coal, and heated by hot cathode off-gas at the same time. A zero-dimension SOFC model is applied and verified by fitting experimental data. Thermodynamic analysis is performed to investigate the integrated system performance, and system sensitivities on anode off-gas back flow ratio, SOFC fuel utilization, temperature and pressure are discussed. Main conclusions are as follows: (1) System overall electricity efficiency reaches 60.7%(HHV) while the gasifier operates at 700 °C and SOFC at 850 °C with system pressure at 3.04 bar; (2) oxygen enriched combustion simplify the carbon-dioxide capture process, which derives CO2 of 99.2% purity, but results in a penalty of 6.7% on system electricity efficiency; (3) with SOFC fuel utilization or temperature increasing, the power output of SOFC increases while GT power output decreases, and increasing system pressure can improve both the performance of SOFC and GT.

  11. 14 CFR 25.833 - Combustion heating systems.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Combustion heating systems. 25.833 Section 25.833 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... Combustion heating systems. Combustion heaters must be approved. [Amdt. 25-72, 55 FR 29783, July 20, 1990...

  12. 14 CFR 25.833 - Combustion heating systems.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Combustion heating systems. 25.833 Section 25.833 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... Combustion heating systems. Combustion heaters must be approved. [Amdt. 25-72, 55 FR 29783, July 20, 1990...

  13. 14 CFR 25.833 - Combustion heating systems.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Combustion heating systems. 25.833 Section 25.833 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... Combustion heating systems. Combustion heaters must be approved. [Amdt. 25-72, 55 FR 29783, July 20, 1990...

  14. 14 CFR 25.833 - Combustion heating systems.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Combustion heating systems. 25.833 Section 25.833 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... Combustion heating systems. Combustion heaters must be approved. [Amdt. 25-72, 55 FR 29783, July 20, 1990...

  15. 14 CFR 25.833 - Combustion heating systems.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Combustion heating systems. 25.833 Section 25.833 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... Combustion heating systems. Combustion heaters must be approved. [Amdt. 25-72, 55 FR 29783, July 20, 1990...

  16. Particulate Formation from a Copper Oxide-Based Oxygen Carrier in Chemical Looping Combustion for CO2 Capture

    EPA Science Inventory

    Attrition behavior and particle loss of a copper oxide-based oxygen carrier from a methane chemical looping combustion (CLC) process was investigated in a fluidized bed reactor. The aerodynamic diameters of most elutriated particulates, after passing through a horizontal settling...

  17. Combustion process for synthesis of carbon nanomaterials from liquid hydrocarbon

    DOEpatents

    Diener, Michael D.; Alford, J. Michael; Nabity, James; Hitch, Bradley D.

    2007-01-02

    The present invention provides a combustion apparatus for the production of carbon nanomaterials including fullerenes and fullerenic soot. Most generally the combustion apparatus comprises one or more inlets for introducing an oxygen-containing gas and a hydrocarbon fuel gas in the combustion system such that a flame can be established from the mixed gases, a droplet delivery apparatus for introducing droplets of a liquid hydrocarbon feedstock into the flame, and a collector apparatus for collecting condensable products containing carbon nanomaterials that are generated in the combustion system. The combustion system optionally has a reaction zone downstream of the flame. If this reaction zone is present the hydrocarbon feedstock can be introduced into the flame, the reaction zone or both.

  18. Effect of diluted and preheated oxidizer on the emission of methane flameless combustion

    NASA Astrophysics Data System (ADS)

    Hosseini, Seyed Ehsan; Salehirad, Saber; Wahid, M. A.; Sies, Mohsin Mohd; Saat, Aminuddin

    2012-06-01

    In combustion process, reduction of emissions often accompanies with output efficiency reduction. It means, by using current combustion technique it is difficult to obtainlow pollution and high level of efficiency in the same time. In new combustion system, low NOxengines and burners are studied particularly. Recently flameless or Moderate and Intensive Low oxygen Dilution (MILD) combustion has received special attention in terms of low harmful emissions and low energy consumption. Behavior of combustion with highly preheated air was analyzed to study the change of combustion regime and the reason for the compatibility of high performance and low NOx production. Sustainability of combustion under low oxygen concentration was examined when; the combustion air temperature was above the self-ignition temperature of the fuel. This paper purposes to analyze the NOx emission quantity in conventional combustion and flameless combustion by Chemical Equilibrium with Applications (CEA) software.

  19. Investigation of reactions in a fluidized bed reactor during chemical looping combustion of coal/steam with copper oxide-iron oxide-alumina oxygen carrier

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Siriwardane, Ranjani; Benincosa, William; Riley, Jarrett

    This paper presents data on conversion of two different coals with a chemical looping oxygen carrier, CuO-Fe 2O 3-alumina, and over a range of conditions including steam and various levels of reduction of the oxygen carrier. Reactions of coal/steam/CuO-Fe 2O 3-alumina oxygen carrier and coal/steam/partially reduced CuO-Fe 2O 3-alumina oxygen carrier were investigated with Wyodak coal and Illinois #6 coal in a fluidized bed reactor. Temperature programmed reaction studies indicated that the oxygen carrier enhanced the steam gasification/combustion rates of both coals. Rates of gasification/combustion were higher with Wyodak coal (sub bituminous) than that with Illinois #6 coal (bituminous). Inmore » addition to the increase in reaction rates, the total moles of carbon that were gasified and combusted from coal/steam increased in the presence of the oxygen carrier. The reduced oxygen carrier promoted the water-gas shift reaction when reacted with synthesis gas in the presence of steam, but the reverse water gas shift reaction was observed when steam was not present. The partially reduced oxygen carrier enhanced the production of H 2 from coal/steam, which was different from the observations with un-reduced oxygen carrier. Water splitting reaction to produce H 2 was also observed with the reduced oxygen carrier. CuO-Fe 2O 3-alumina reacted with coal during the temperature ramp to 850 °C even in the absence of steam due to the chemical-looping oxygen uncoupling (CLOU) reaction. Here, the fourier transform infra-red (FTIR) analysis indicated the presence of volatile aromatics during the temperature ramp and these may have also contributed to the reactions with the oxygen carrier in the absence of steam. Increasing steam concentration had a negative effect on the CLOU reaction.« less

  20. Investigation of reactions in a fluidized bed reactor during chemical looping combustion of coal/steam with copper oxide-iron oxide-alumina oxygen carrier

    DOE PAGES

    Siriwardane, Ranjani; Benincosa, William; Riley, Jarrett; ...

    2016-10-06

    This paper presents data on conversion of two different coals with a chemical looping oxygen carrier, CuO-Fe 2O 3-alumina, and over a range of conditions including steam and various levels of reduction of the oxygen carrier. Reactions of coal/steam/CuO-Fe 2O 3-alumina oxygen carrier and coal/steam/partially reduced CuO-Fe 2O 3-alumina oxygen carrier were investigated with Wyodak coal and Illinois #6 coal in a fluidized bed reactor. Temperature programmed reaction studies indicated that the oxygen carrier enhanced the steam gasification/combustion rates of both coals. Rates of gasification/combustion were higher with Wyodak coal (sub bituminous) than that with Illinois #6 coal (bituminous). Inmore » addition to the increase in reaction rates, the total moles of carbon that were gasified and combusted from coal/steam increased in the presence of the oxygen carrier. The reduced oxygen carrier promoted the water-gas shift reaction when reacted with synthesis gas in the presence of steam, but the reverse water gas shift reaction was observed when steam was not present. The partially reduced oxygen carrier enhanced the production of H 2 from coal/steam, which was different from the observations with un-reduced oxygen carrier. Water splitting reaction to produce H 2 was also observed with the reduced oxygen carrier. CuO-Fe 2O 3-alumina reacted with coal during the temperature ramp to 850 °C even in the absence of steam due to the chemical-looping oxygen uncoupling (CLOU) reaction. Here, the fourier transform infra-red (FTIR) analysis indicated the presence of volatile aromatics during the temperature ramp and these may have also contributed to the reactions with the oxygen carrier in the absence of steam. Increasing steam concentration had a negative effect on the CLOU reaction.« less

  1. Effect of temperature on reduction of CaSO{sub 4} oxygen carrier in chemical-looping combustion of simulated coal gas in a fluidized bed reactor

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Song, Q.L.; Xiao, R.; Deng, Z.Y.

    2008-12-15

    Chemical-looping combustion (CLC) is a promising combustion technology for gaseous and solid fuel with efficient use of energy and inherent separation of CO{sub 2}. The concept of a coal-fueled CLC system using, calcium sulfate (CaSO{sub 4}) as oxygen carrier is proposed in this study. Reduction tests of CaSO{sub 4} oxygen carrier with simulated coal gas were performed in a laboratory-scale fluidized bed reactor in the temperature range of 890-950{degree}C. A high concentration of CO{sub 2} was obtained at the initial reduction period. CaSO{sub 4} oxygen carrier exhibited high reactivity initially and decreased gradually at the late period of reduction. Themore » sulfur release during the reduction of CaSO{sub 4} as oxygen carrier was also observed and analyzed. H{sub 2} and CO{sub 2} conversions were greatly influenced by reduction temperature. The oxygen carrier conversion and mass-based reaction rates during the reduction at typical temperatures were compared. Higher temperatures would enhance reaction rates and result in high conversion of oxygen carrier. An XRD patterns study indicated that CaS was the dominant product of reduction and the variation of relative intensity with temperature is in agreement with the solid conversion. ESEM analysis indicated that the surface structure of oxygen carrier particles changed significantly from impervious to porous after reduction. EDS analysis also demonstrated the transfer of oxygen from the oxygen carrier to the fuel gas and a certain amount of sulfur loss and CaO formation on the surface at higher temperatures. The reduction kinetics of CaSO{sub 4} oxygen carrier was explored with the shrinking unreacted-core model. The apparent kinetic parameters were obtained, and the kinetic equation well predicted the experimental data. Finally, some basic considerations on the use of CaSO{sub 4} oxygen carrier in a CLC system for solid fuels were discussed.« less

  2. The Search for Nonflammable Solvent Alternatives for Cleaning Aerospace Oxygen Systems

    NASA Technical Reports Server (NTRS)

    Mitchell, Mark A.; Lowrey, Nikki

    2012-01-01

    To obtain a high degree of cleanliness without risk of corrosion or hazardous reactivity, hydrochlorofluorocarbon (HCFC)-225 is used for cleaning and cleanliness verification of oxygen system components used on NASA fs bipropellant launch vehicles, associated test stands and support equipment. HCFC-225 is a Class II Ozone Depleting Substance (ODS ]II) that was introduced to replace chlorofluorocarbon (CFC)-113, a Class I ODS solvent that is now banned. To meet environmental regulations to eliminate the use of ozone depleting substances, a replacement solvent is required for HCFC ]225 that is effective at removing oils, greases, and particulate from large oxygen system components, is compatible with materials used in the construction of these systems, and is nonflammable and non ]reactive in enriched oxygen environments. A solvent replacement is also required for aviator fs breathing oxygen systems and other related equipment currently cleaned and verified with HCFC ]225 and stockpiled CFC -113. Requirements and challenges in the search for nonflammable replacement solvents are discussed.

  3. Beryllium particle combustion

    NASA Technical Reports Server (NTRS)

    Prentice, J. L.

    1972-01-01

    A two-year study of the combustion efficiency of single beryllium droplets burning in a variety of oxidizers (primarily mixtures of oxygen/argon and oxygen/nitrogen) is summarized. An advanced laser heating technique was used to acquire systematic quantitative data on the burning of single beryllium droplets at atmospheric pressure. The research confirmed the sensitivity of beryllium droplet combustion to the chemistry of environmental species and provides experimental documentation for the nitrogen-induced droplet fragmentation of burning beryllium droplets.

  4. Test System to Study the Ignition of Metals by Polymers in Oxygen

    NASA Technical Reports Server (NTRS)

    Shoffstall, Michael S.; Stoltzfus, Joel M.; Fries, Joseph (Technical Monitor)

    2000-01-01

    A new test system that uses Laser energy to ignite a polymer promoter has been developed at the NASA White Sands Test Facility. It will facilitate the study of the spread of fire from a burning polymer material to the metal surrounding it. The system can be used to answer questions regarding the effects of configuration on ignition and combustion. The data obtained from this test could also be used to develop mathematical models for analyzing the effects of configuration on ignition and combustion. The system features a 10,000-psi (69-MPa) test chamber with sight glass windows on either end and a 25-watt carbon dioxide Laser for an ignition source. The test system can be used with gaseous oxygen, nitrogen or any mixture of the two gases. To minimize the effect of preheating the metallic, the polymer is ignited with a minimal amount of Laser energy. Igniting the polymer in this fashion also simplifies the thermodynamic analysis of the ignition and propagation reactions. The system is very robust, versatile and straightforward to use. Depending on the test pressure and configuration, the test system operator can perform as many as 20 tests per day. Test results verify that ignition and combustion of the metallic sample is not only dependent on pressure, material type and temperature, but configuration of both the polymer promoter and metallic sample. Both 6061 aluminum and 316 stainless steel 0.25-inch (6.35-mm) diameter rods with a standard 0-ring groove were tested with Buna-N, Silicone, Teflon and Viton 0-rings. The system ignited all four types of 0-rings in oxygen at pressures ranging from ambient to 10,000 psi (69 MPa). However, neither the stainless steel nor the aluminum rods on which the O-rings were mounted ignited in any test conditions. Future testing may be done on the 0.25-inch (6.35-mm) rod and O-ring configuration to evaluate the lack of ignition in these tests. Future configurations may include a plug of polymer in the base of the sample and replicas

  5. Proposed fast-response oxygen monitoring and control system for the Langley 8-foot high-temperature tunnel

    NASA Technical Reports Server (NTRS)

    Singh, J. J.; Davis, W. T.; Puster, R. L.

    1983-01-01

    A fast-response oxygen monitoring and control system, based on a Y2O3-stabilized ZrO2 sensor, was developed and tested in the laboratory. The system is capable of maintaining oxygen concentration in the CH4-O2-air combustion product gases at 20.9 + or - 1.0 percent. If the oxygen concentration in the exhaust stream differs from that in normal air by 25 percent or more, an alarm signal is provided for automatic tunnel shutdown. The overall prototype system response time was reduced from about 1 sec in the original configuration to about 0.2 sec. The basis of operation and the results of laboratory tests of the system are described.

  6. Recovery Act: Novel Oxygen Carriers for Coal-fueled Chemical Looping

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Pan, Wei-Ping; Cao, Yan

    2012-11-30

    Chemical Looping Combustion (CLC) could totally negate the necessity of pure oxygen by using oxygen carriers for purification of CO{sub 2} stream during combustion. It splits the single fuel combustion reaction into two linked reactions using oxygen carriers. The two linked reactions are the oxidation of oxygen carriers in the air reactor using air, and the reduction of oxygen carriers in the fuel reactor using fuels (i.e. coal). Generally metal/metal oxides are used as oxygen carriers and operated in a cyclic mode. Chemical looping combustion significantly improves the energy conversion efficiency, in terms of the electricity generation, because it improvesmore » the reversibility of the fuel combustion process through two linked parallel processes, compared to the conventional combustion process, which is operated far away from its thermo-equilibrium. Under the current carbon-constraint environment, it has been a promising carbon capture technology in terms of fuel combustion for power generation. Its disadvantage is that it is less mature in terms of technological commercialization. In this DOE-funded project, accomplishment is made by developing a series of advanced copper-based oxygen carriers, with properties of the higher oxygen-transfer capability, a favorable thermodynamics to generate high purity of CO{sub 2}, the higher reactivity, the attrition-resistance, the thermal stability in red-ox cycles and the achievement of the auto-thermal heat balance. This will be achieved into three phases in three consecutive years. The selected oxygen carriers with final-determined formula were tested in a scaled-up 10kW coal-fueled chemical looping combustion facility. This scaled-up evaluation tests (2-day, 8-hour per day) indicated that, there was no tendency of agglomeration of copper-based oxygen carriers. Only trace-amount of coke or carbon deposits on the copper-based oxygen carriers in the fuel reactor. There was also no evidence to show the sulphidization of

  7. On the progressive enrichment of the oxygen isotopic composition of water along a leaf.

    PubMed

    Farquhar, G. D.; Gan, K. S.

    2003-06-01

    A model has been derived for the enrichment of heavy isotopes of water in leaves, including progressive enrichment along the leaf. In the model, lighter water is preferentially transpired leaving heavier water to diffuse back into the xylem and be carried further along the leaf. For this pattern to be pronounced, the ratio of advection to diffusion (Péclet number) has to be large in the longitudinal direction, and small in the radial direction. The progressive enrichment along the xylem is less than that occurring at the sites of evaporation in the mesophyll, depending on the isolation afforded by the radial Péclet number. There is an upper bound on enrichment, and effects of ground tissue associated with major veins are included. When transpiration rate is spatially nonuniform, averaging of enrichment occurs more naturally with transpiration weighting than with area-based weighting. This gives zero average enrichment of transpired water, the modified Craig-Gordon equation for average enrichment at the sites of evaporation and the Farquhar and Lloyd (In Stable Isotopes and Plant Carbon-Water Relations, pp. 47-70. Academic Press, New York, USA, 1993) prediction for mesophyll water. Earlier results on the isotopic composition of evolved oxygen and of retro-diffused carbon dioxide are preserved if these processes vary in parallel with transpiration rate. Parallel variation should be indicated approximately by uniform carbon isotope discrimination across the leaf.

  8. Combined O2/combustibles solid electrolyte gas monitoring device

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Hickam, W.M.; Lin, C.; Zomp, J.M.

    1980-11-04

    A circuit means in combination with a conventional oxygen ion conductive solid electrolyte cell establishes the cell in a voltage mode for the purposes of measuring excess oxygen and developing a voltage signal indicative thereof, and switching the cell to a current mode of operation in response to an excess combustible environment wherein current drawn by the cell to pump oxygen for combustible reaction with the excess combustibles environment is measured as an indication of the combustibles content of the gas.

  9. Transition nozzle combustion system

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kim, Won-Wook; McMahan, Kevin Weston; Maldonado, Jaime Javier

    The present application provides a combustion system for use with a cooling flow. The combustion system may include a head end, an aft end, a transition nozzle extending from the head end to the aft end, and an impingement sleeve surrounding the transition nozzle. The impingement sleeve may define a first cavity in communication with the head end for a first portion of the cooling flow and a second cavity in communication with the aft end for a second portion of the cooling flow. The transition nozzle may include a number of cooling holes thereon in communication with the secondmore » portion of the cooling flow.« less

  10. Detailed Kinetic Mechanism of the Combustion of Homogeneous Gaseous Mixtures with Participation of Oxygen-containing Oxidants

    NASA Astrophysics Data System (ADS)

    Baevich, V. Ya

    1987-05-01

    The kinetic mechanisms of the oxidation and combustion of hydrogen, methane, methyl alcohol, acetylene, ethylene, ethane, and methylamine, using oxygen as well as hydrogen peroxide and nitric acid as oxidants, are discussed. The calculated and experimental data obtained under static conditions, in a flow, during flame propagation, and in shock tubes are compared. The bibliography includes 184 references.

  11. Internal and surface phenomena in metal combustion

    NASA Technical Reports Server (NTRS)

    Dreizin, Edward L.; Molodetsky, Irina E.; Law, Chung K.

    1995-01-01

    Combustion of metals has been widely studied in the past, primarily because of their high oxidation enthalpies. A general understanding of metal combustion has been developed based on the recognition of the existence of both vapor-phase and surface reactions and involvement of the reaction products in the ensuing heterogeneous combustion. However, distinct features often observed in metal particle combustion, such as brightness oscillations and jumps (spearpoints), disruptive burning, and non-symmetric flames are not currently understood. Recent metal combustion experiments using uniform high-temperature metal droplets produced by a novel micro-arc technique have indicated that oxygen dissolves in the interior of burning particles of certain metals and that the subsequent transformations of the metal-oxygen solutions into stoichiometric oxides are accompanied with sufficient heat release to cause observed brightness and temperature jumps. Similar oxygen dissolution has been observed in recent experiments on bulk iron combustion but has not been associated with such dramatic effects. This research addresses heterogeneous metal droplet combustion, specifically focusing on oxygen penetration into the burning metal droplets, and its influence on the metal combustion rate, temperature history, and disruptive burning. A unique feature of the experimental approach is the combination of the microgravity environment with a novel micro-arc Generator of Monodispersed Metal Droplets (GEMMED), ensuring repeatable formation and ignition of uniform metal droplets with controllable initial temperature and velocity. The droplet initial temperatures can be adjusted within a wide range from just above the metal melting point, which provides means to ignite droplets instantly upon entering an oxygen containing environment. Initial droplet velocity will be set equal to zero allowing one to organize metal combustion microgravity experiments in a fashion similar to usual microgravity

  12. Effect of fuel zinc content on toxicological responses of particulate matter from pellet combustion in vitro.

    PubMed

    Uski, O; Jalava, P I; Happo, M S; Torvela, T; Leskinen, J; Mäki-Paakkanen, J; Tissari, J; Sippula, O; Lamberg, H; Jokiniemi, J; Hirvonen, M-R

    2015-04-01

    Significant amounts of transition metals such as zinc, cadmium and copper can become enriched in the fine particle fraction during biomass combustion with Zn being one of the most abundant transition metals in wood combustion. These metals may have an important role in the toxicological properties of particulate matter (PM). Indeed, many epidemiological studies have found associations between mortality and PM Zn content. The role of Zn toxicity on combustion PM was investigated. Pellets enriched with 170, 480 and 2300 mg Zn/kg of fuel were manufactured. Emission samples were generated using a pellet boiler and the four types of PM samples; native, Zn-low, Zn-medium and Zn-high were collected with an impactor from diluted flue gas. The RAW 264.7 macrophage cell line was exposed for 24h to different doses (15, 50,150 and 300 μg ml(-1)) of the emission samples to investigate their ability to cause cytotoxicity, to generate reactive oxygen species (ROS), to altering the cell cycle and to trigger genotoxicity as well as to promote inflammation. Zn enriched pellets combusted in a pellet boiler produced emission PM containing ZnO. Even the Zn-low sample caused extensive cell cycle arrest and there was massive cell death of RAW 264.7 macrophages at the two highest PM doses. Moreover, only the Zn-enriched emission samples induced a dose dependent ROS response in the exposed cells. Inflammatory responses were at a low level but macrophage inflammatory protein 2 reached a statistically significant level after exposure of RAW 264.7 macrophages to ZnO containing emission particles. ZnO content of the samples was associated with significant toxicity in almost all measured endpoints. Thus, ZnO may be a key component producing toxicological responses in the PM emissions from efficient wood combustion. Zn as well as the other transition metals, may contribute a significant amount to the ROS responses evoked by ambient PM. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. Experimental study of biomass gasification with oxygen-enriched air in fluidized bed gasifier.

    PubMed

    Liu, Lingqin; Huang, Yaji; Cao, Jianhua; Liu, Changqi; Dong, Lu; Xu, Ligang; Zha, Jianrui

    2018-06-01

    Considering the universality, renewability and cleanness of biomass, an experimental research is carried out using rice straw in a two-stage fluidized bed. The experimental analysis identified the relevant parameters in the operation of the two-stage fluidized bed to investigate the properties of biomass enriched air gasification. Results show that higher gasification temperature is conducive to enhance the gasification performance. An increasing ER is shown to go against adding gas heat value. When oxygen concentration increases from 21% to 45%, the gas heating value increases from 4.00MJ/kg to 5.24MJ/kg and the gasification efficiency increases from 29.60% to 33.59%, which shows higher oxygen concentration is conducive to higher quality gas and higher gasification efficiency. A secondary oxygen injection leads to reduction of tar concentration from 15.78g/Nm 3 to 10.24g/Nm 3 . The optimal secondary oxygen ratio is about 33.00%. When the secondary oxygen ratio increased to 46.86%, monocyclic aromatics reduced from 28.17% to 19.65% and PAHs increased from 34.97% to 44.05%, leading to the increase aromatization of tar. Copyright © 2018 Elsevier B.V. All rights reserved.

  14. Jet plume injection and combustion system for internal combustion engines

    DOEpatents

    Oppenheim, A.K.; Maxson, J.A.; Hensinger, D.M.

    1993-12-21

    An improved combustion system for an internal combustion engine is disclosed wherein a rich air/fuel mixture is furnished at high pressure to one or more jet plume generator cavities adjacent to a cylinder and then injected through one or more orifices from the cavities into the head space of the cylinder to form one or more turbulent jet plumes in the head space of the cylinder prior to ignition of the rich air/fuel mixture in the cavity of the jet plume generator. The portion of the rich air/fuel mixture remaining in the cavity of the generator is then ignited to provide a secondary jet, comprising incomplete combustion products which are injected into the cylinder to initiate combustion in the already formed turbulent jet plume. Formation of the turbulent jet plume in the head space of the cylinder prior to ignition has been found to yield a higher maximum combustion pressure in the cylinder, as well as shortening the time period to attain such a maximum pressure. 24 figures.

  15. Jet plume injection and combustion system for internal combustion engines

    DOEpatents

    Oppenheim, Antoni K.; Maxson, James A.; Hensinger, David M.

    1993-01-01

    An improved combustion system for an internal combustion engine is disclosed wherein a rich air/fuel mixture is furnished at high pressure to one or more jet plume generator cavities adjacent to a cylinder and then injected through one or more orifices from the cavities into the head space of the cylinder to form one or more turbulent jet plumes in the head space of the cylinder prior to ignition of the rich air/fuel mixture in the cavity of the jet plume generator. The portion of the rich air/fuel mixture remaining in the cavity of the generator is then ignited to provide a secondary jet, comprising incomplete combustion products which are injected into the cylinder to initiate combustion in the already formed turbulent jet plume. Formation of the turbulent jet plume in the head space of the cylinder prior to ignition has been found to yield a higher maximum combustion pressure in the cylinder, as well as shortening the time period to attain such a maximum pressure.

  16. Gas analysis system for the Eight Foot High Temperature Tunnel

    NASA Technical Reports Server (NTRS)

    Leighty, Bradley D.; Davis, Patricia P.; Upchurch, Billy T.; Puster, Richard L.

    1992-01-01

    This paper describes the development of a gas collection and analysis system that is to be installed in the Eight-Foot High Temperature Tunnel (8' HTT) at NASA's Langley Research Center. This system will be used to analyze the test gas medium that results after burning a methane-air mixture to achieve the proper tunnel test parameters. The system consists of a sampling rake, a gas sample storage array, and a gas chromatographic system. Gas samples will be analyzed after each run to assure that proper combustion takes place in the tunnel resulting in a correctly balanced composition of the test gas medium. The proper ratio of gas species is critically necessary in order for the proper operation and testing of scramjet engines in the tunnel. After a variety of methane-air burn conditions have been analyzed, additional oxygen will be introduced into the combusted gas and the enriched test gas medium analyzed. The pre/post enrichment sets of data will be compared to verify that the gas species of the test gas medium is correctly balanced for testing of air-breathing engines.

  17. The Effects of Gravity on Combustion and Structure Formation During Combustion Synthesis in Gasless Systems

    NASA Technical Reports Server (NTRS)

    Varma, Arvind; Mukasyan, Alexander; Pelekh, Aleksey

    1997-01-01

    There have been relatively few publications examining the role of gravity during combustion synthesis (CS), mostly involving thermite systems. The main goal of this research was to study the influence of gravity on the combustion characteristics of heterogeneous gasless systems. In addition, some aspects of microstructure formation processes which occur during gasless CS were also studied. Four directions for experimental investigation have been explored: (1) the influence of gravity force on the characteristic features of heterogeneous combustion wave propagation (average velocity, instantaneous velocities, shape of combustion front); (2) the combustion of highly porous mixtures (with porosity greater than that for loose powders), which cannot be obtained in normal gravity; (3) the effect of gravity on sample expansion during combustion, in order to produce highly porous materials under microgravity conditions; and (4) the effect of gravity on the structure formation mechanism during the combustion synthesis of poreless composite materials.

  18. Leaner Lifted-Flame Combustion Enabled by the Use of an Oxygenated Fuel in an Optical CI Engine

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Gehmlich, Ryan K.; Dumitrescu, Cosmin E.; Wang, Yefu

    Leaner lifted-flame combustion (LLFC) is a mixing-controlled combustion strategy for compression-ignition engines that does not produce soot because the equivalence ratio at the lift-off length, Φ(H), is less than or equal to approximately two. In addition to preventing soot formation, LLFC can simultaneously control emissions of nitrogen oxides because it is tolerant to the use of exhaust-gas recirculation for lowering in-cylinder temperatures. LLFC can be achieved through the use of oxygenated fuels and enhanced fuel/charge-gas mixing upstream of the lift-off length. Enhanced mixing can be obtained via higher injection pressures, smaller injector orifice diameters, lower intake-manifold and coolant temperatures, and/ormore » more retarded injection timings. This study focuses on the effects of an oxygenated fuel blend (T50) made up of 50% by volume tri-propylene glycol mono-methyl ether with a #2 ULSD emissions-certification fuel (CFA), compared against baseline testing of the CFA fuel without the oxygenate. Experimental measurements include crank-angle resolved natural luminosity (NL) and chemiluminescence (CL) imaging diagnostics. EGR is simulated by adding nitrogen and carbon dioxide to the intake charge to produce a 16% intake-oxygen mole fraction (XO2), and results are compared against cases with no charge dilution (i.e., 21% XO2). Initial experiments with a two-hole tip achieved soot-free LLFC at low loads with the T50 fuel, 240 MPa injection pressure, 50 °C intake-manifold temperature (IMT), 95 °C coolant temperature, and -5 crank-angle degree (CAD) after top-dead-center (ATDC) start of combustion (SOC) timing. The strategy was extended to more moderate loads by employing a 6-hole injector tip, where lowering the IMT to 30 °C, reducing the coolant temperature to 85 °C, and retarding the SOC timing to +5 CAD ATDC resulted in sustained LLFC at both 21% and 16% XO2 at up to 6.2 bar gross indicated mean effective pressure (gIMEP) with T50. The

  19. Leaner Lifted-Flame Combustion Enabled by the Use of an Oxygenated Fuel in an Optical CI Engine

    DOE PAGES

    Gehmlich, Ryan K.; Dumitrescu, Cosmin E.; Wang, Yefu; ...

    2016-04-05

    Leaner lifted-flame combustion (LLFC) is a mixing-controlled combustion strategy for compression-ignition engines that does not produce soot because the equivalence ratio at the lift-off length, Φ(H), is less than or equal to approximately two. In addition to preventing soot formation, LLFC can simultaneously control emissions of nitrogen oxides because it is tolerant to the use of exhaust-gas recirculation for lowering in-cylinder temperatures. LLFC can be achieved through the use of oxygenated fuels and enhanced fuel/charge-gas mixing upstream of the lift-off length. Enhanced mixing can be obtained via higher injection pressures, smaller injector orifice diameters, lower intake-manifold and coolant temperatures, and/ormore » more retarded injection timings. This study focuses on the effects of an oxygenated fuel blend (T50) made up of 50% by volume tri-propylene glycol mono-methyl ether with a #2 ULSD emissions-certification fuel (CFA), compared against baseline testing of the CFA fuel without the oxygenate. Experimental measurements include crank-angle resolved natural luminosity (NL) and chemiluminescence (CL) imaging diagnostics. EGR is simulated by adding nitrogen and carbon dioxide to the intake charge to produce a 16% intake-oxygen mole fraction (XO2), and results are compared against cases with no charge dilution (i.e., 21% XO2). Initial experiments with a two-hole tip achieved soot-free LLFC at low loads with the T50 fuel, 240 MPa injection pressure, 50 °C intake-manifold temperature (IMT), 95 °C coolant temperature, and -5 crank-angle degree (CAD) after top-dead-center (ATDC) start of combustion (SOC) timing. The strategy was extended to more moderate loads by employing a 6-hole injector tip, where lowering the IMT to 30 °C, reducing the coolant temperature to 85 °C, and retarding the SOC timing to +5 CAD ATDC resulted in sustained LLFC at both 21% and 16% XO2 at up to 6.2 bar gross indicated mean effective pressure (gIMEP) with T50. The

  20. Apparatus for photocatalytic destruction of internal combustion engine emissions during cold start

    DOEpatents

    Janata, Jiri; McVay, Gary L.; Peden, Charles H.; Exarhos, Gregory J.

    1998-01-01

    A method and apparatus for the destruction of emissions from an internal combustion engine wherein a substrate coated with TiO.sub.2 is exposed to a light source in the exhaust system of an internal combustion engine thereby catalyzing oxidation/reduction reactions between gaseous hydrocarbons, carbon monoxide, nitrogen oxides and oxygen in the exhaust of the internal combustion engine.

  1. Thermal ignition combustion system

    DOEpatents

    Kamo, R.; Kakwani, R.M.; Valdmanis, E.; Woods, M.E.

    1988-04-19

    The thermal ignition combustion system comprises means for providing walls defining an ignition chamber, the walls being made of a material having a thermal conductivity greater than 20 W/m C and a specific heat greater than 480 J/kg C with the ignition chamber being in constant communication with the main combustion chamber, means for maintaining the temperature of the walls above a threshold temperature capable of causing ignition of a fuel, and means for conducting fuel to the ignition chamber. 8 figs.

  2. Thermal ignition combustion system

    DOEpatents

    Kamo, Roy; Kakwani, Ramesh M.; Valdmanis, Edgars; Woods, Melvins E.

    1988-01-01

    The thermal ignition combustion system comprises means for providing walls defining an ignition chamber, the walls being made of a material having a thermal conductivity greater than 20 W/m.degree. C. and a specific heat greater than 480 J/kg.degree. C. with the ignition chamber being in constant communication with the main combustion chamber, means for maintaining the temperature of the walls above a threshold temperature capable of causing ignition of a fuel, and means for conducting fuel to the ignition chamber.

  3. Effect of 13C enrichment and sugar type on analysis of sugars by gas chromatography/combustion/isotope ratio mass spectrometry.

    PubMed

    Baumann, Karen; Dignac, Marie-France; Bardoux, Gérard; Rumpel, Cornelia

    2012-09-15

    The objective of this investigation was to test gas-chromatographic compound-specific analysis for studies on the isotopic composition of (13)C-enriched sugar molecules. The effects of (13)C enrichment and type of sugar (C5, C6) will provide valuable information on isotopic correction for future studies employing (13)C-enriched sugars. Five sugar solutions of xylose, mannose and glucose with (13)C enrichments ranging between 1.1 and 1.5 atom-% were prepared. The (13)C enrichments of the initial sugars were measured by elemental analyser/isotope ratio mass spectrometry (EA/IRMS); (13)C enrichments for derivatised sugars were obtained by gas chromatography/combustion/IRMS (GC/C/IRMS). The linear relationships between the (13)C enrichments of the initial sugars and the values for the derivatised sugars were sugar-type dependent. Corrections for GC/C/IRMS values took into account the kinetic isotope effect (KIE) of the derivatising agent associated with the coefficient (K(d)) and a newly introduced second coefficient (K(c)) associated with the KIE of the sugar. While K(d) was constant, K(c) varied with sugar type. During derivatisation acetate groups with (12)C and sugars with more (13)C reacted faster. Coefficients for the specific ranges of (13)C enrichments under study have to be assessed and the reactions of different sugar types have to be taken into account to avoid underestimation of (13)C enrichment of up to 9% (C5) or overestimation of up to 4% (C6). Copyright © 2012 John Wiley & Sons, Ltd.

  4. Dynamic Exergy Method for Evaluating the Control and Operation of Oxy-Combustion Boiler Island Systems.

    PubMed

    Jin, Bo; Zhao, Haibo; Zheng, Chuguang; Liang, Zhiwu

    2017-01-03

    Exergy-based methods are widely applied to assess the performance of energy conversion systems; however, these methods mainly focus on a certain steady-state and have limited applications for evaluating the control impacts on system operation. To dynamically obtain the thermodynamic behavior and reveal the influences of control structures, layers and loops, on system energy performance, a dynamic exergy method is developed, improved, and applied to a complex oxy-combustion boiler island system for the first time. The three most common operating scenarios are studied, and the results show that the flow rate change process leads to less energy consumption than oxygen purity and air in-leakage change processes. The variation of oxygen purity produces the largest impact on system operation, and the operating parameter sensitivity is not affected by the presence of process control. The control system saves energy during flow rate and oxygen purity change processes, while it consumes energy during the air in-leakage change process. More attention should be paid to the oxygen purity change because it requires the largest control cost. In the control system, the supervisory control layer requires the greatest energy consumption and the largest control cost to maintain operating targets, while the steam control loops cause the main energy consumption.

  5. On-line measurement of heat of combustion

    NASA Technical Reports Server (NTRS)

    Chaturvedi, S. K.; Chegini, H.

    1988-01-01

    An experimental method for an on-line measurement of heat of combustion of a gaseous hydrocarbon fuel mixture of unknown composition is developed. It involves combustion of a test gas with a known quantity of air to achieve a predetermined oxygen concentration level in the combustion products. This is accomplished by a feedback controller which maintains the gas volumetric flow rate at a level consistent with the desired oxygen concentration in the products. The heat of combustion is determined from a known correlation with the gas volumetric flow rate. An on-line microcomputer accesses the gas volumetric flow data, and displays the heat of combustion values at desired time intervals.

  6. Effects of mesh type on a non-premixed model in a flameless combustion simulation

    NASA Astrophysics Data System (ADS)

    Komonhirun, Seekharin; Yongyingsakthavorn, Pisit; Nontakeaw, Udomkiat

    2018-01-01

    Flameless combustion is a recently developed combustion system, which provides zero emission product. This phenomenon requires auto-ignition by supplying high-temperature air with low oxygen concentration. The flame is vanished and colorless. Temperature of the flameless combustion is less than that of a conventional case, where NOx reactions can be well suppressed. To design a flameless combustor, the computational fluid dynamics (CFD) is employed. The designed air-and-fuel injection method can be applied with the turbulent and non-premixed models. Due to the fact that nature of turbulent non-premixed combustion is based on molecular randomness, inappropriate mesh type can lead to significant numerical errors. Therefore, this research aims to numerically investigate the effects of mesh type on flameless combustion characteristics, which is a primary step of design process. Different meshes, i.e. tetrahedral, hexagonal are selected. Boundary conditions are 5% of oxygen and 900 K of air-inlet temperature for the flameless combustion, and 21% of oxygen and 300 K of air-inlet temperature for the conventional case. The results are finally presented and discussed in terms of velocity streamlines, and contours of turbulent kinetic energy and viscosity, temperature, and combustion products.

  7. Apparatus for photocatalytic destruction of internal combustion engine emissions during cold start

    DOEpatents

    Janata, J.; McVay, G.L.; Peden, C.H.; Exarhos, G.J.

    1998-07-14

    A method and apparatus are disclosed for the destruction of emissions from an internal combustion engine wherein a substrate coated with TiO{sub 2} is exposed to a light source in the exhaust system of an internal combustion engine thereby catalyzing oxidation/reduction reactions between gaseous hydrocarbons, carbon monoxide, nitrogen oxides and oxygen in the exhaust of the internal combustion engine. 4 figs.

  8. X-33 Combustion-Wave Ignition System Tested

    NASA Technical Reports Server (NTRS)

    Liou, Larry C.

    1999-01-01

    The NASA Lewis Research Center, in cooperation with Rocketdyne, the Boeing Company, tested a novel rocket engine ignition system, called the combustion-wave ignition system, in its Research Combustion Laboratory. This ignition system greatly simplifies ignition in rocket engines that have a large number of combustors. The particular system tested was designed and fabricated by Rocketdyne for the national experimental spacecraft, X-33, which uses Rocketdyne s aerospike rocket engines. The goal of the tests was to verify the system design and define its operational characteristics. Results will contribute to the eventual successful flight of X-33. Furthermore, the combustion-wave ignition system, after it is better understood and refined on the basis of the test results and, later, flight-proven onboard X-33, could become an important candidate engine ignition system for our Nation s next-generation reusable launch vehicle.

  9. Solid Fuel - Oxygen Fired Combustion for Production of Nodular Reduced Iron to Reduce CO2 Emissions and Improve Energy Efficiencies

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Donald R. Fosnacht; Richard F. Kiesel; David W. Hendrickson

    2011-12-22

    The current trend in the steel industry is an increase in iron and steel produced in electric arc furnaces (EAF) and a gradual decline in conventional steelmaking from taconite pellets in blast furnaces. In order to expand the opportunities for the existing iron ore mines beyond their blast furnace customer base, a new material is needed to satisfy the market demands of the emerging steel industry while utilizing the existing infrastructure and materials handling capabilities. This demand creates opportunity to convert iron ore or other iron bearing materials to Nodular Reduced Iron (NRI) in a recently designed Linear Hearth Furnacemore » (LHF). NRI is a metallized iron product containing 98.5 to 96.0% iron and 2.5 to 4% C. It is essentially a scrap substitute with little impurity that can be utilized in a variety of steelmaking processes, especially the electric arc furnace. The objective of this project was to focus on reducing the greenhouse gas emissions (GHG) through reducing the energy intensity using specialized combustion systems, increasing production and the use of biomass derived carbon sources in this process. This research examined the use of a solid fuel-oxygen fired combustion system and compared the results from this system with both oxygen-fuel and air-fuel combustion systems. The solid pulverized fuels tested included various coals and a bio-coal produced from woody biomass in a specially constructed pilot scale torrefaction reactor at the Coleraine Minerals Research Laboratory (CMRL). In addition to combustion, the application of bio-coal was also tested as a means to produce a reducing atmosphere during key points in the fusion process, and as a reducing agent for ore conversion to metallic iron to capture the advantage of its inherent reduced carbon footprint. The results from this study indicate that the approaches taken can reduce both greenhouse gas emissions and the associated energy intensity with the Linear Hearth Furnace process for

  10. Pyrolysis reactor and fluidized bed combustion chamber

    DOEpatents

    Green, Norman W.

    1981-01-06

    A solid carbonaceous material is pyrolyzed in a descending flow pyrolysis reactor in the presence of a particulate source of heat to yield a particulate carbon containing solid residue. The particulate source of heat is obtained by educting with a gaseous source of oxygen the particulate carbon containing solid residue from a fluidized bed into a first combustion zone coupled to a second combustion zone. A source of oxygen is introduced into the second combustion zone to oxidize carbon monoxide formed in the first combustion zone to heat the solid residue to the temperature of the particulate source of heat.

  11. Improvement of wound healing by regulated oxygen-enriched negative pressure-assisted wound therapy in a rabbit model.

    PubMed

    Li, Y Z; Hu, X D; Lai, X M; Li, Y F; Lei, Y

    2018-01-01

    Development of drug therapies and other techniques for wound care have resulted in significant improvement of the cure rate and shortening of the healing time for wounds. A modified technique of regulated oxygen-enriched negative pressure-assisted wound therapy (RO-NPT) has been reported. To evaluate the efficacy and impact of RO-NPT on wound recovery and inflammation. Infected wounds were established on 40 adult female white rabbits, which were then randomized to one of four groups: O 2 group, regulated negative pressure-assisted wound therapy (RNPT) group, regulated oxygen-enriched negative pressure-assisted wound therapy (RO-NPT) group and healthy control (HC) group. Each day, the O 2 group was treated with a constant oxygen supply (1 L/min) to the wound, while the RNPT group was treated with continuous regulated negative pressure (70 ± 5 mmHg) and the RNPT + O 2 group was treated with both. The HC group was treated with gauze dressing alone, which was changed every day. Leucocyte count, colony count and wound-healing rate were calculated. Levels of tumour necrosis factor (TNF)-α, interleukin (IL)-1β and IL-8 were evaluated by ELISA. RO-RNPT significantly decreased bacterial count and TNF-α level, and increased the wound-healing rate. IL-1β, IL-8 and leucocyte count had a tendency to increase in the early phase of inflammation and a tendency to decrease in the later phase of inflammation in the RO-RNPT group. RO-NPT therapy assisted wound recovery and inflammation control compared with the RNPT and oxygen-enriched therapies. RO-NPT therapy also increased levels of IL-1β and IL-8 and attenuated expression of TNF-α in the early phase of inflammation. © 2017 British Association of Dermatologists.

  12. Highly time-resolved imaging of combustion and pyrolysis product concentrations in solid fuel combustion: NO formation in a burning cigarette.

    PubMed

    Zimmermann, Ralf; Hertz-Schünemann, Romy; Ehlert, Sven; Liu, Chuan; McAdam, Kevin; Baker, Richard; Streibel, Thorsten

    2015-02-03

    The highly dynamic, heterogeneous combustion process within a burning cigarette was investigated by a miniaturized extractive sampling probe (microprobe) coupled to photoionization mass spectrometry using soft laser single photon ionization (SPI) for online real-time detection of molecular ions of combustion and pyrolysis products. Research cigarettes smoked by a smoking machine are used as a reproducible model system for solid-state biomass combustion, which up to now is not addressable by current combustion-diagnostic tools. By combining repetitively recorded online measurement sequences from different sampling locations in an imaging approach, highly time- and space-resolved quantitative distribution maps of, e.g., nitrogen monoxide, benzene, and oxygen concentrations were obtained at a near microscopic level. The obtained quantitative distribution maps represent a time-resolved, movie-like imaging of the respective compound's formation and destruction zones in the various combustion and pyrolysis regions of a cigarette during puffing. Furthermore, spatially resolved kinetic data were ascertainable. The here demonstrated methodology can also be applied to various heterogenic combustion/pyrolysis or reaction model systems, such as fossil- or biomass-fuel pellet combustion or to a positional resolved analysis of heterogenic catalytic reactions.

  13. Development of fire resistant electronic configurations for use in oxygen enriched environments

    NASA Technical Reports Server (NTRS)

    Smith, F. J.

    1975-01-01

    Design concepts for electronic black boxes and modules were tested in oxygen enriched atmospheres, and it was found that various types of sealed configurations would generally eliminate any flammability hazard. The type of configuration and its construction was found to be of more importance in the elimination of flammability hazards in electronic configurations than the types of materials utilized in them. The design concepts developed for fire hazard free electronic configurations for use in manned space programs are applicable for the design of electronic hardware for any use or environment.

  14. High performance electrodes in vanadium redox flow batteries through oxygen-enriched thermal activation

    NASA Astrophysics Data System (ADS)

    Pezeshki, Alan M.; Clement, Jason T.; Veith, Gabriel M.; Zawodzinski, Thomas A.; Mench, Matthew M.

    2015-10-01

    The roundtrip electrochemical energy efficiency is improved from 63% to 76% at a current density of 200 mA cm-2 in an all-vanadium redox flow battery (VRFB) by utilizing modified carbon paper electrodes in the high-performance no-gap design. Heat treatment of the carbon paper electrodes in a 42% oxygen/58% nitrogen atmosphere increases the electrochemically wetted surface area from 0.24 to 51.22 m2 g-1, resulting in a 100-140 mV decrease in activation overpotential at operationally relevant current densities. An enriched oxygen environment decreases the amount of treatment time required to achieve high surface area. The increased efficiency and greater depth of discharge doubles the total usable energy stored in a fixed amount of electrolyte during operation at 200 mA cm-2.

  15. Energy Efficient Engine (E3) combustion system component technology performance report

    NASA Technical Reports Server (NTRS)

    Burrus, D. L.; Chahrour, C. A.; Foltz, H. L.; Sabla, P. E.; Seto, S. P.; Taylor, J. R.

    1984-01-01

    The Energy Efficient Engine (E3) combustor effort was conducted as part of the overall NASA/GE E3 Program. This effort included the selection of an advanced double-annular combustion system design. The primary intent of this effort was to evolve a design that meets the stringent emissions and life goals of the E3, as well as all of the usual performance requirements of combustion systems for modern turbofan engines. Numerous detailed design studies were conducted to define the features of the combustion system design. Development test hardware was fabricated, and an extensive testing effort was undertaken to evaluate the combustion system subcomponents in order to verify and refine the design. Technology derived from this effort was incorporated into the engine combustion hardware design. The advanced engine combustion system was then evaluated in component testing to verify the design intent. What evolved from this effort was an advanced combustion system capable of satisfying all of the combustion system design objectives and requirements of the E3.

  16. Combustion synthesis of complex oxides

    NASA Astrophysics Data System (ADS)

    Ming, Qimin

    Advanced ceramic materials have numerous applications in electronic engineering, chemical engineering, and semiconductor industry. The synthesis of these materials at an economical cost is the bottleneck in the application of these materials. Self-propagating High-temperature Synthesis (SHS) is a new technique for producing these materials for exothermic systems by a combustion wave that propagates and produces high purity products. The full potential of SHS to produce advanced materials has not yet been utilized. In this study, we used SHS to prepare two types of complex oxides: La 1-xSrxCrO3, La0.89Sr0.1 MnO3, powders, used to make interconnect and cathode of solid oxide fuel cells; and chromium- and gallium-doped La1-xSr xFeO3-delta, mixed ionic and electronic conductive powders used to manufacture ceramic membranes for oxygen separation. A thermodynamic feasibility analysis shows that the oxidation of Cr is the main source of heat generation of La1-xSrxCrO 3, which maintains a stable reaction front. Replacing part of the metallic Cr in the reaction mixture by its oxides decreases the combustion temperature and front propagating velocity and modifies the product morphology. The oxygen needed for the Cr oxidation is provided by the decomposition of CrO3 , SrO2, or NaClO4. The predicted and observed combustion temperatures are in reasonable agreement. TG/DTA analyses of La1-xSrxCrO3 indicated that SHS stability was strongly affected by the transport of oxygen between the two regions, in which oxygen was generated by the decomposition of either NaClO4 or CrO3 and that in which it was consumed by the oxidation of Cr. Partial melting at the high combustion temperature during SHS of La 1-xSrxMnO3 increased product homogeneity. The electrical conductivity at 1000°C in air of SHS-produced cathode material (of 180 O-1·cm-1) matches that of the commercial product made by other processes. However, the SHS process provides much higher productivity and decreases processing

  17. Influence of the Structure of a Solid-Fuel Mixture on the Thermal Efficiency of the Combustion Chamber of an Engine System

    NASA Astrophysics Data System (ADS)

    Futko, S. I.; Koznacheev, I. A.; Ermolaeva, E. M.

    2014-11-01

    On the basis of thermodynamic calculations, the features of the combustion of a solid-fuel mixture based on the glycidyl azide polymer were investigated, the thermal cycle of the combustion chamber of a model engine system was analyzed, and the efficiency of this chamber was determined for a wide range of pressures in it and different ratios between the components of the combustible mixture. It was established that, when the pressure in the combustion chamber of an engine system increases, two maxima arise successively on the dependence of the thermal efficiency of the chamber on the weight fractions of the components of the combustible mixture and that the first maximum shifts to the side of smaller concentrations of the glycidyl azide polymer with increase in the pressure in the chamber; the position of the second maximum is independent of this pressure, coincides with the minimum on the dependence of the rate of combustion of the mixture, and corresponds to the point of its structural phase transition at which the mole fractions of the carbon and oxygen atoms in the mixture are equal. The results obtained were interpreted on the basis of the Le-Chatelier principle.

  18. Fuel properties to enable lifted-flame combustion

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kurtz, Eric

    The Fuel Properties to Enable Lifted-Flame Combustion project responded directly to solicitation DE-FOA-0000239 AOI 1A, Fuels and Lubricants for Advanced Combustion Regimes. This subtopic was intended to encompass clean and highly-efficient, liquid-fueled combustion engines to achieve extremely low engine-out nitrogen oxides (NOx) and particulate matter (PM) as a target and similar efficiency as state-of-the-art direct injection diesel engines. The intent of this project was to identify how fuel properties can be used to achieve controllable Leaner Lifted Flame Combustion (LLFC) with low NOx and PM emissions. Specifically, this project was expected to identify and test key fuel properties to enablemore » LLFC and their compatibility with current fuel systems and to enhance combustion models to capture the effect of fuel properties on advanced combustion. Successful demonstration of LLFC may reduce the need for after treatment devices, thereby reducing costs and improving thermal efficiency. The project team consisted of key technical personnel from Ford Motor Company (FMC), the University of Wisconsin-Madison (UW), Sandia National Laboratories (SNL) and Lawrence Livermore National Laboratories (LLNL). Each partner had key roles in achieving project objectives. FMC investigated fuel properties relating to LLFC and sooting tendency. Together, FMC and UW developed and integrated 3D combustion models to capture fuel property combustion effects. FMC used these modeling results to develop a combustion system and define fuel properties to support a single-cylinder demonstration of fuel-enabled LLFC. UW investigated modeling the flame characteristics and emissions behavior of different fuels, including those with different cetane number and oxygen content. SNL led spray combustion experiments to quantify the effect of key fuel properties on combustion characteristics critical for LLFC, as well as single cylinder optical engine experiments to improve fundamental

  19. SnO2 promoted by alkali metal oxides for soot combustion: The effects of surface oxygen mobility and abundance on the activity

    NASA Astrophysics Data System (ADS)

    Rao, Cheng; Shen, Jiating; Wang, Fumin; Peng, Honggen; Xu, Xianglan; Zhan, Hangping; Fang, Xiuzhong; Liu, Jianjun; Liu, Wenming; Wang, Xiang

    2018-03-01

    In this study, SnO2-based catalysts promoted by different alkali metal oxides with a Sn/M (M = Li, Na, K, Cs) molar ratio of 9/1 have been prepared for soot combustion. In comparison with the un-modified SnO2 support, the activity of the modified catalysts has been evidently enhanced, following the sequence of CsSn1-9 > KSn1-9 > NaSn1-9 > LiSn1-9 > SnO2. As testified by Raman, H2-TPR, soot-TPR-MS, XPS and O2-TPD results, the incorporation of various alkali metal oxides can induce the formation of more abundant and mobile oxygen species on the surface of the catalysts. Moreover, quantified results have proved that the amount of the surface active oxygen species is nearly proportional to the activity of the catalysts. CsSn1-9, the catalyst promoted by cesium oxide, owns the largest amount of surface mobile oxygen species, thus having the highest activity among all the studied catalysts. It is concluded that the amount of surface active and mobile oxygen species is the major factor determining the activity of the catalysts for soot combustion.

  20. Carbon deposition model for oxygen-hydrocarbon combustion, volume 1

    NASA Technical Reports Server (NTRS)

    Hernandez, R.; Ito, J. I.; Niiya, K. Y.

    1987-01-01

    Presented are details of the design, fabrication, and testing of subscale hardware used in the evaluation of carbon deposition characteristics of liquid oxygen and three hydrocarbon fuels for both main chamber and preburner/gas generator operating conditions. In main chamber conditions, the deposition of carbon on the combustion chamber wall was investigated at mixture ratios of 2.0 to 4.0 and at pressures of 1000 to 1500 psia. No carbon deposition on the chamber walls was detected at these main chamber mixture ratios. In preburner/gas generator operating conditions, the deposition of carbon on the turbine simulator tubes was evaluated at mixture ratios of 0.20 to 0.60 and at chamber pressures of 720 to 1650 psia. The results of the tests showed carbon deposition rate to be a strong function of mixture ratio and a weak function of chamber pressure. Further analyses evaluated the operational consequences of carbon deposition on preburner/gas generator performance. The report is in two volumes, of which this is Volume 1 covering the main body of the report plus Appendixes A through D.

  1. Carbon Deposition Model for Oxygen-Hydrocarbon Combustion, Volume 2

    NASA Technical Reports Server (NTRS)

    Hernandez, R.; Ito, J. I.; Niiya, K. Y.

    1987-01-01

    Presented are details of the design, fabrication, and testing of subscale hardware used in the evaluation of carbon deposition characteristics of liquid oxygen and three hydrocarbon fuels for both main chamber and preburner/gas generator operating conditions. In main chamber conditions, the deposition of carbon on the combustion chamber wall was investigated at mixture ratios of 2.0 to 4.0 and at chamber pressures of 1000 to 1500 psia. No carbon deposition on chamber walls was detected at these main chamber mixture ratios. In preburner/gas generator operating conditions, the deposition of carbon on the turbine simulator tubes was evaluated at mixture ratios of 0.20 to 0.60 and at chamber pressures of 720 to 1650 psia. The results of the tests showed carbon deposition rate to be a strong function of mixture ratio and a weak function of chamber pressure. Further analyses evaluated the operational concequences of carbon deposition on preburner/gas generator performance. This is Volume 2 of the report, which contains data plots of all the test programs.

  2. WASTE COMBUSTION SYSTEM ANALYSIS

    EPA Science Inventory

    The report gives results of a study of biomass combustion alternatives. The objective was to evaluate the thermal performance and costs of available and developing biomass systems. The characteristics of available biomass fuels were reviewed, and the performance parameters of alt...

  3. 16. VIEW OF THE ENRICHED URANIUM RECOVERY SYSTEM. ENRICHED URANIUM ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    16. VIEW OF THE ENRICHED URANIUM RECOVERY SYSTEM. ENRICHED URANIUM RECOVERY PROCESSED RELATIVELY PURE MATERIALS AND SOLUTIONS AND SOLID RESIDUES WITH RELATIVELY LOW URANIUM CONTENT. URANIUM RECOVERY INVOLVED BOTH SLOW AND FAST PROCESSES. (4/4/66) - Rocky Flats Plant, General Manufacturing, Support, Records-Central Computing, Southern portion of Plant, Golden, Jefferson County, CO

  4. Reduced No.sub.x combustion method

    DOEpatents

    Delano, Mark A.

    1991-01-01

    A combustion method enabling reduced NO.sub.x formation wherein fuel and oxidant are separately injected into a combustion zone in a defined velocity relation, combustion gases are aspirated into the oxidant stream prior to intermixture with the fuel, and the fuel is maintained free from contact with oxygen until the intermixture.

  5. System and method for engine combustion

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Sczomak, David P.; Gallon, Robert J.; Solomon, Arun S.

    A combustion system for use with one or more cylinder bores of an internal combustion engine includes at least one cylinder head defining first and second intake ports in fluid communication with the one or more cylinder bores. A flap is adjustably connected to the at least one cylinder head. The flap includes a first flap portion cooperating with the first intake port extending from an arm and a second flap portion cooperating with the second intake port extending from the arm and disposed adjacent the first flap portion. A controller in electrical communication with an actuator monitors the conditionmore » of the engine and actuates the flap to position the first and second flap portions between first and second positions to create a first combustion condition and a second combustion condition.« less

  6. Reducing NOx Emissions for a 600 MWe Down-Fired Pulverized-Coal Utility Boiler by Applying a Novel Combustion System.

    PubMed

    Ma, Lun; Fang, Qingyan; Lv, Dangzhen; Zhang, Cheng; Chen, Yiping; Chen, Gang; Duan, Xuenong; Wang, Xihuan

    2015-11-03

    A novel combustion system was applied to a 600 MWe Foster Wheeler (FW) down-fired pulverized-coal utility boiler to solve high NOx emissions, without causing an obvious increase in the carbon content of fly ash. The unit included moving fuel-lean nozzles from the arches to the front/rear walls and rearranging staged air as well as introducing separated overfire air (SOFA). Numerical simulations were carried out under the original and novel combustion systems to evaluate the performance of combustion and NOx emissions in the furnace. The simulated results were found to be in good agreement with the in situ measurements. The novel combustion system enlarged the recirculation zones below the arches, thereby strengthening the combustion stability considerably. The coal/air downward penetration depth was markedly extended, and the pulverized-coal travel path in the lower furnace significantly increased, which contributed to the burnout degree. The introduction of SOFA resulted in a low-oxygen and strong-reducing atmosphere in the lower furnace region to reduce NOx emissions evidently. The industrial measurements showed that NOx emissions at full load decreased significantly by 50%, from 1501 mg/m3 (O2 at 6%) to 751 mg/m3 (O2 at 6%). The carbon content in the fly ash increased only slightly, from 4.13 to 4.30%.

  7. Effect of dissolved oxygen concentration (microaerobic and aerobic) on selective enrichment culture for bioaugmentation of acidic industrial wastewater.

    PubMed

    Quan, Ying; Han, Hui; Zheng, Shaokui

    2012-09-01

    The successful application of bioaugmentation is largely dependent on the selective enrichment of culture with regards to pH, temperature, salt, or specific toxic organic pollutants. In this study, we investigated the effect of dissolved oxygen (DO) concentrations (aerobic, >2 mg L(-1); microaerobic, <1 mg L(-1)) on yeast enrichment culture for bioaugmentation of acidic industrial wastewater (pH 3.9-4.7). Clone library analyses revealed that the yeast community shifted in response to different DO levels, and that Candida humilis and Candida pseudolambica were individually dominant in the aerobic and microaerobic enrichment cultures. This would significantly influence the isolation results, and further hinder bioaugmentation due to differences in DO environments during the enrichment and application periods. However, differences in the selective enrichment culture cannot be predicted based on differences in pollutant removal performance. Thus, DO concentrations (aerobic/microaerobic) should be considered a secondary selective pressure to achieve successful bioaugmentation. Copyright © 2012 Elsevier Ltd. All rights reserved.

  8. Effect of combustion temperature on the emission of trace elements under O2/CO2 atmosphere during coal combustion

    NASA Astrophysics Data System (ADS)

    Qu, Chengrui; Zhang, Mo; Mann, Michael. D.

    2018-03-01

    The effect of combustion temperature on the emission of trace elementswas studied under O2/CO2 atmosphere during coal combustion in a laboratory scale fluidized bed combustor. The elemental composition of fine fly ash particles collected with a low pressure impactor(LPI)was quantified by X-Ray F1uorescence Spectrometer (XRF). The elemental composition of coal and bottom ash was quantified byinductively coupled plasma-atomic emission spectroscopy (ICP-AES). The results indicate that the contents of Mn, Zn, Cd and Cr in the fly ash increase with the rise of combustion temperature. It is found that the enrichment of Zn and Cd is greater in the submicrometer particles than the supermicrometer particles, but Mn and Cr do not enrich in the submicrometer particles. Mn, Zn, Cd and Cr display one peak around 0.1 μm. The relative enrichment factor (Rij) of four elements is in the order of Zn, Cd, Mn and Cr. Zn and Cd are mostly retained in fly ashwhileMn and Cr are retained in both the fly ash and bottom ash.

  9. Cavity Coupled Aeroramp Injector Combustion Study

    DTIC Science & Technology

    2009-06-01

    Fluorescence RC-18 Propulsion Research Cell 18 at Wright-Patterson Air Force Base Scramjet Supersonic Combustion Ramjet TDLAS Tunable Diode Laser...aerothrottle starting device. There were also mass flow meters on the vitiator oxygen and natural gas supplies. The ethylene fuel used in the DMSJ...PSI System 10 Hz Health Monitoring System ~0.75 Hz Sensors A/D Converters Buffer Database/Console 5 Hz 22 Figure 16: Nominal

  10. Multi-Point Combustion System: Final Report

    NASA Technical Reports Server (NTRS)

    Goeke, Jerry; Pack, Spencer; Zink, Gregory; Ryon, Jason

    2014-01-01

    A low-NOx emission combustor concept has been developed for NASA's Environmentally Responsible Aircraft (ERA) program to meet N+2 emissions goals for a 70,000 lb thrust engine application. These goals include 75 percent reduction of LTO NOx from CAEP6 standards without increasing CO, UHC, or smoke from that of current state of the art. An additional key factor in this work is to improve lean combustion stability over that of previous work performed on similar technology in the early 2000s. The purpose of this paper is to present the final report for the NASA contract. This work included the design, analysis, and test of a multi-point combustion system. All design work was based on the results of Computational Fluid Dynamics modeling with the end results tested on a medium pressure combustion rig at the UC and a medium pressure combustion rig at GRC. The theories behind the designs, results of analysis, and experimental test data will be discussed in this report. The combustion system consists of five radially staged rows of injectors, where ten small scale injectors are used in place of a single traditional nozzle. Major accomplishments of the current work include the design of a Multipoint Lean Direct Injection (MLDI) array and associated air blast and pilot fuel injectors, which is expected to meet or exceed the goal of a 75 percent reduction in LTO NOx from CAEP6 standards. This design incorporates a reduced number of injectors over previous multipoint designs, simplified and lightweight components, and a very compact combustor section. Additional outcomes of the program are validation that the design of these combustion systems can be aided by the use of Computational Fluid Dynamics to predict and reduce emissions. Furthermore, the staging of fuel through the individually controlled radially staged injector rows successfully demonstrated improved low power operability as well as improvements in emissions over previous multipoint designs. Additional comparison

  11. Simulation of Combustion Systems with Realistic g-Jitter

    NASA Technical Reports Server (NTRS)

    Mell, W. E.; McGrattan, K. B.; Nakamura, Y.; Baum, H. R.

    2001-01-01

    A number of facilities are available for microgravity combustion experiments: aircraft, drop towers, sounding rockets, the space shuttle, and, in the future, the International Space Station (ISS). Acceleration disturbances or g-jitter about the background level of reduced gravity exist in all these microgravity facilities. While g-jitter is routinely measured, a quantitative comparison of the quality of g-jitter among the different microgravity facilities, in terms of its affects on combustion experiments, has not been compiled. Low frequency g-jitter (< 1 Hz) has been repeatedly observed to disturb a number of combustion systems. Guidelines regarding tolerable levels of acceleration disturbances for combustion experiments have been developed for use in the design of ISS experiments. The validity of these guidelines, however, remains unknown. In this project a transient, 3-D numerical model is under development to simulate the effects of realistic g-jitter on a number of combustion systems. The measured acceleration vector or some representation of it can be used as input to the simulation.

  12. Visualization of turbulent combustion of TNT detonation products in a steel vessel

    NASA Astrophysics Data System (ADS)

    Wolański, P.; Gut, Z.; Trzciński, W. A.; Szymańczyk, L.; Paszula, J.

    Mixing and afterburning of TNT detonation products in a steel vessel are recorded by the use of the Schlieren visualization system and high speed photography. The vessel is filled with air or 50% oxygen enriched air. Overpressure histories at the vessel wall are also recorded by using pressure transducers. In these experiments nitrogen, air or 50% oxygen enriched air are used as vessel fillers. The Oppenheim-Kuhl theory of thermodynamics of closed systems is applied to estimate the released energy on the basis of pressure histories.

  13. Combustion of diesel fuel from a toxicological perspective. I. Origin of incomplete combustion products.

    PubMed

    Scheepers, P T; Bos, R P

    1992-01-01

    Since the use of diesel engines is still increasing, the contribution of their incomplete combustion products to air pollution is becoming ever more important. The presence of irritating and genotoxic substances in both the gas phase and the particulate phase constituents is considered to have significant health implications. The quantity of soot particles and the particle-associated organics emitted from the tail pipe of a diesel-powered vehicle depend primarily on the engine type and combustion conditions but also on fuel properties. The quantity of soot particles in the emissions is determined by the balance between the rate of formation and subsequent oxidation. Organics are absorbed onto carbon cores in the cylinder, in the exhaust system, in the atmosphere and even on the filter during sample collection. Diesel fuel contains polycyclic aromatic hydrocarbons (PAHs) and some alkyl derivatives. Both groups of compounds may survive the combustion process. PAHs are formed by the combustion of crankcase oil or may be resuspended from engine and/or exhaust deposits. The conversion of parent PAHs to oxygenated and nitrated PAHs in the combustion chamber or in the exhaust system is related to the vast amount of excess combustion air that is supplied to the engine and the high combustion temperature. Whether the occurrence of these derivatives is characteristic for the composition of diesel engine exhaust remains to be ascertained. After the emission of the particles, their properties may change because of atmospheric processes such as aging and resuspension. The particle-associated organics may also be subject to (photo)chemical conversions or the components may change during sampling and analysis. Measurement of emissions of incomplete combustion products as determined on a chassis dynamometer provides knowledge of the chemical composition of the particle-associated organics. This knowledge is useful as a basis for a toxicological evaluation of the health hazards of

  14. In-water gas combustion for thrust production

    NASA Astrophysics Data System (ADS)

    Teslenko, V. S.; Drozhzhin, A. P.; Medvedev, R. N.

    2017-07-01

    The paper presents the results of experimental study for hydrodynamic processes occurring during combustion of a stoichiometric mixture propane-oxygen in combustion chambers with different configurations and submerged into water. The pulses of force acting upon a thrust wall were measured for different geometries: cylindrical, conic, hemispherical, including the case of gas combustion near a flat thrust wall. After a single charge of stoichiometric mixture propane-oxygen is burnt near the thrust wall, the process of cyclic generation of force pulses develops. The first pulse is generated due to pressure growth during gas combustion, and the following pulses are the result of hydrodynamic pulsations of the gaseous cavity. Experiments demonstrated that efficient generation of thrust occurs if all bubble pulsations are used during combustion of a single gas combustion. In the series of experiments, the specific impulse on the thrust wall was in the range 104-105 s (105-106 m/s) with account for positive and negative components of impulse.

  15. AKR1C1 as a Biomarker for Differentiating the Biological Effects of Combustible from Non-Combustible Tobacco Products.

    PubMed

    Woo, Sangsoon; Gao, Hong; Henderson, David; Zacharias, Wolfgang; Liu, Gang; Tran, Quynh T; Prasad, G L

    2017-05-03

    Smoking has been established as a major risk factor for developing oral squamous cell carcinoma (OSCC), but less attention has been paid to the effects of smokeless tobacco products. Our objective is to identify potential biomarkers to distinguish the biological effects of combustible tobacco products from those of non-combustible ones using oral cell lines. Normal human gingival epithelial cells (HGEC), non-metastatic (101A) and metastatic (101B) OSCC cell lines were exposed to different tobacco product preparations (TPPs) including cigarette smoke total particulate matter (TPM), whole-smoke conditioned media (WS-CM), smokeless tobacco extract in complete artificial saliva (STE), or nicotine (NIC) alone. We performed microarray-based gene expression profiling and found 3456 probe sets from 101A, 1432 probe sets from 101B, and 2717 probe sets from HGEC to be differentially expressed. Gene Set Enrichment Analysis (GSEA) revealed xenobiotic metabolism and steroid biosynthesis were the top two pathways that were upregulated by combustible but not by non-combustible TPPs. Notably, aldo-keto reductase genes, AKR1C1 and AKR1C2 , were the core genes in the top enriched pathways and were statistically upregulated more than eight-fold by combustible TPPs. Quantitative real time polymerase chain reaction (qRT-PCR) results statistically support AKR1C1 as a potential biomarker for differentiating the biological effects of combustible from non-combustible tobacco products.

  16. AKR1C1 as a Biomarker for Differentiating the Biological Effects of Combustible from Non-Combustible Tobacco Products

    PubMed Central

    Woo, Sangsoon; Gao, Hong; Henderson, David; Zacharias, Wolfgang; Liu, Gang; Tran, Quynh T.; Prasad, G.L.

    2017-01-01

    Smoking has been established as a major risk factor for developing oral squamous cell carcinoma (OSCC), but less attention has been paid to the effects of smokeless tobacco products. Our objective is to identify potential biomarkers to distinguish the biological effects of combustible tobacco products from those of non-combustible ones using oral cell lines. Normal human gingival epithelial cells (HGEC), non-metastatic (101A) and metastatic (101B) OSCC cell lines were exposed to different tobacco product preparations (TPPs) including cigarette smoke total particulate matter (TPM), whole-smoke conditioned media (WS-CM), smokeless tobacco extract in complete artificial saliva (STE), or nicotine (NIC) alone. We performed microarray-based gene expression profiling and found 3456 probe sets from 101A, 1432 probe sets from 101B, and 2717 probe sets from HGEC to be differentially expressed. Gene Set Enrichment Analysis (GSEA) revealed xenobiotic metabolism and steroid biosynthesis were the top two pathways that were upregulated by combustible but not by non-combustible TPPs. Notably, aldo-keto reductase genes, AKR1C1 and AKR1C2, were the core genes in the top enriched pathways and were statistically upregulated more than eight-fold by combustible TPPs. Quantitative real time polymerase chain reaction (qRT-PCR) results statistically support AKR1C1 as a potential biomarker for differentiating the biological effects of combustible from non-combustible tobacco products. PMID:28467356

  17. Ash particulate formation from pulverized coal under oxy-fuel combustion conditions.

    PubMed

    Jia, Yunlu; Lighty, JoAnn S

    2012-05-01

    Aerosol particulates are generated by coal combustion. The amount and properties of aerosol particulates, specifically size distribution and composition, can be affected by combustion conditions. Understanding the formation of these particles is important for predicting emissions and understanding potential deposition. Oxy-fuel combustion conditions utilize an oxygen-enriched gas environment with CO(2). The high concentration of CO(2) is a result of recycle flue gas which is used to maintain temperature. A hypothesis is that high CO(2) concentration reduces the vaporization of refractory oxides from combustion. A high-temperature drop-tube furnace was used under different oxygen concentrations and CO(2) versus N(2) to study the effects of furnace temperature, coal type, and gas phase conditions on particulate formation. A scanning mobility particle sizer (SMPS) and aerodynamic particle sizer (APS) were utilized for particle size distributions ranging from 14.3 nm to 20 μm. In addition, particles were collected on a Berner low pressure impactor (BLPI) for elemental analysis using scanning electron microscopy and energy dispersive spectroscopy. Three particle size modes were seen: ultrafine (below 0.1 μm), fine (0.1 to 1.0 μm), and coarse (above 1 μm). Ultrafine mass concentrations were directly related to estimated particle temperature, increasing with increasing temperature. For high silicon and calcium coals, Utah Skyline and PRB, there was a secondary effect due to CO(2) and the hypothesized reaction. Illinois #6, a high sulfur coal, had the highest amount of ultrafine mass and most of the sulfur was concentrated in the ultrafine and fine modes. Fine and coarse mode mass concentrations did not show a temperature or CO(2) relationship. (The table of contents graphic and abstract graphic are adapted from ref 27.). © 2012 American Chemical Society

  18. Dry low NOx combustion system with pre-mixed direct-injection secondary fuel nozzle

    DOEpatents

    Zuo, Baifang; Johnson, Thomas; Ziminsky, Willy; Khan, Abdul

    2013-12-17

    A combustion system includes a first combustion chamber and a second combustion chamber. The second combustion chamber is positioned downstream of the first combustion chamber. The combustion system also includes a pre-mixed, direct-injection secondary fuel nozzle. The pre-mixed, direct-injection secondary fuel nozzle extends through the first combustion chamber into the second combustion chamber.

  19. Nano-Enriched and Autonomous Sensing Framework for Dissolved Oxygen.

    PubMed

    Shehata, Nader; Azab, Mohammed; Kandas, Ishac; Meehan, Kathleen

    2015-08-14

    This paper investigates a nano-enhanced wireless sensing framework for dissolved oxygen (DO). The system integrates a nanosensor that employs cerium oxide (ceria) nanoparticles to monitor the concentration of DO in aqueous media via optical fluorescence quenching. We propose a comprehensive sensing framework with the nanosensor equipped with a digital interface where the sensor output is digitized and dispatched wirelessly to a trustworthy data collection and analysis framework for consolidation and information extraction. The proposed system collects and processes the sensor readings to provide clear indications about the current or the anticipated dissolved oxygen levels in the aqueous media.

  20. Promoted Ignition and Burning Tests of Stainless Steel in Flowing and Nonflowing Oxygen

    NASA Technical Reports Server (NTRS)

    Forsyth, Elliot T.; Maes, Miguel; Stoltzfus, Joel M.; Bachelier, Frederic

    2003-01-01

    The Industry-Sponsored Metals Combustion Test Program 96-1 was coordinated through Wendell Hull & Associates, Inc. on behalf of several contributing companies, and all design and testing was performed at the NASA White Sands Test Facility. Phase I of this test program studied the threshold pressure for self-sustained burning of various types and sizes of stain less steel rods in nonflowing oxygen, as observed in Standard Test Method for Determining the Combustion Behavior of Metallic Materials in Oxygen-Enriched Atmospheres (ASTM G 124-95). Phase II studied the ignition and propagation of burning of 316L stainless steel rods and pipe in flowing gaseous oxygen. The test sample configurations were chosen to replicate previous promoted ignition and burning tests as well as to represent geometries and cross-sectional thicknesses common in industrial piping applications. The gas pressw'es and velocities for the test matrix were selected to generally compare with CGA G-4.4 guidelines for the use of stain less steel in oxygen service. This paper summarizes the results from the Phase I nonflowing oxygen tests and presents in detail the results of the Phase II flowing oxygen tests. The maximum sample burn-length is shown as a function of test pressure in Phase 1 and also as a function of gas velocity in Phase IT. These results indicate that flowing oxygen, under the given test conditions, significantly affects maximum sample burn length as compared to nonflowing oxygen. Supplementary flowing oxygen test data on stainless steel rods from a follow-up test program are consistent with these results and are presented herein.

  1. Sorbent control of trace metals in sewage sludge combustion and incineration

    NASA Astrophysics Data System (ADS)

    Naruse, I.; Yao, H.; Mkilaha, I. S. N.

    2003-05-01

    Coal and wastes combustion have become an important issue not only in terms of energy generation but also environmental conservation. The need for alternative fuels and wastes management has made the two energy sources of importance. However, the utilization of the two is faced with problems of impurity trace metals in the fuel. These metals usually speciate during combustion or incineration leading to generation of fumes and subsequently particles. This paper reports on the study aimed at understanding the speciation of trace metals and their emission from combustion systems as particulates. Experiments carried out using a down-flow furnace and theoretical study carried out using lead, chromium and cadmium as basic metals had shown that their speciation and subsequent emission is controlled by both chemical composition and physical properties of the fuel. The physical and chemical and physical properties of the fuel and their respective compounds and the operating conditions of the incineration and combustion system control the enrichment of the particles with trace metals.

  2. Method and apparatus for detecting combustion instability in continuous combustion systems

    DOEpatents

    Benson, Kelly J.; Thornton, Jimmy D.; Richards, George A.; Straub, Douglas L.

    2006-08-29

    An apparatus and method to sense the onset of combustion stability is presented. An electrode is positioned in a turbine combustion chamber such that the electrode is exposed to gases in the combustion chamber. A control module applies a voltage potential to the electrode and detects a combustion ionization signal and determines if there is an oscillation in the combustion ionization signal indicative of the occurrence of combustion stability or the onset of combustion instability. A second electrode held in a coplanar but spaced apart manner by an insulating member from the electrode provides a combustion ionization signal to the control module when the first electrode fails. The control module broadcasts a notice if the parameters indicate the combustion process is at the onset of combustion instability or broadcasts an alarm signal if the parameters indicate the combustion process is unstable.

  3. Combustion of solid fuel slabs with gaseous oxygen in a hybrid motor analog

    NASA Technical Reports Server (NTRS)

    Chiaverini, Martin J.; Harting, George C.; Lu, Yeu-Cherng; Kuo, Kenneth K.; Serin, Nadir; Johnson, David K.

    1995-01-01

    Using a high-pressure, two-dimensional hybrid motor, an experimental investigation was conducted on fundamental processes involved in hybrid rocket combustion. HTPB (Hydroxyl-terminated Polybutadiene) fuel cross-linked with diisocyanate was burned with gaseous oxygen (GOX) under various operating conditions. Large-amplitude pressure oscillations were encountered in earlier test runs. After identifying the source of instability and decoupling the GOX feed-line system and combustion chamber, the pressure oscillations were drastically reduced from plus or minus 20% of the localized mean pressure to an acceptable range of plus or minus 1.5%. Embedded fine--wire thermocouples indicated that the surface temperature of the burning fuel was around 1000 K depending upon axial locations and operating conditions. Also, except near the leading edge region, the subsurface thermal wave profiles in the upstream locations are thicker than those in the downstream locations since the solid-fuel regression rate, in general, increases with distance along the fuel slab. The recovered solid fuel slabs in the laminar portion of the boundary layer exhibited smooth surfaces, indicating the existence of a liquid melt layer on the burning fuel surface in the upstream region. After the transition section, which displayed distinct transverse striations, the surface roughness pattern became quite random and very pronounced in the downstream turbulent boundary-layer region. Both real-time X-ray radiography and ultrasonic pulse echo techniques were used to determine the instantaneous web thicknesses and instantaneous solid-fuel regression rates over certain portions of the fuel slabs. Globally averaged and axially dependent but time-averaged regression rates were also obtained and presented. Several tests were conducted using, simultaneously, one translucent fuel slab and one fuel slab processed with carbon black powder. The addition of carbon black did not affect the measured regression rates or

  4. Heterogeneity and O-16-Enrichments in Oxygen Isotope Ratios of Olivine from Chondrules in the Mokoia CV3 Chondrite

    NASA Technical Reports Server (NTRS)

    Jones, R. H.; Leshin, L. A.; Guan, Y.

    2002-01-01

    Two chondrules from Mokoia contain olivine in which oxygen isotopes are extremely heterogeneous, with some grains highly enriched in O-16. These data provide an important link between CAIs and chondrules. Additional information is contained in the original extended abstract.

  5. DEMONSTRATION BULLETIN: CELLO PULSE COMBUSTION BURNER SYSTEM/SONOTECH INC.

    EPA Science Inventory

    Sonotech, Inc. (Sonotech), of Atlanta, GA, the developer of the Cello® pulse combustion burner, claims that its burner system can be beneficial to a variety of combustion processes. The system incorporates a combustor that can be tuned to induce large amplitude sonic pulsation...

  6. Method and system for controlled combustion engines

    DOEpatents

    Oppenheim, A. K.

    1990-01-01

    A system for controlling combustion in internal combustion engines of both the Diesel or Otto type, which relies on establishing fluid dynamic conditions and structures wherein fuel and air are entrained, mixed and caused to be ignited in the interior of a multiplicity of eddies, and where these structures are caused to sequentially fill the headspace of the cylinders.

  7. Assessment of Literature Related to Combustion Appliance Venting Systems

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Rapp, V. H.; Less, B. D.; Singer, B. C.

    In many residential building retrofit programs, air tightening to increase energy efficiency is often constrained by safety concerns with naturally vented combustion appliances. Tighter residential buildings more readily depressurize when exhaust equipment is operated, making combustion appliances more prone to backdraft or spill combustion exhaust into the living space. Several measures, such as installation guidelines, vent sizing codes, and combustion safety diagnostics, are in place with the intent to prevent backdrafting and combustion spillage, but the diagnostics conflict and the risk mitigation objective is inconsistent. This literature review summarizes the metrics and diagnostics used to assess combustion safety, documents theirmore » technical basis, and investigates their risk mitigations. It compiles information from the following: codes for combustion appliance venting and installation; standards and guidelines for combustion safety diagnostics; research evaluating combustion safety diagnostics; research investigating wind effects on building depressurization and venting; and software for simulating vent system performance.« less

  8. Free-radicals aided combustion with scramjet applications

    NASA Technical Reports Server (NTRS)

    Yang, Yongsheng; Kumar, Ramohalli

    1992-01-01

    Theoretical and experimental investigations aimed at altering 'nature-prescribed' combustion rates in hydrogen/hydrocarbon reactions with (enriched) air are presented. The intent is to anchor flame zones in supersonic streams, and to ensure proper and controllable complete combustion in scramjets. The diagnostics are nonintrusive through IR thermograms and acoustic emissions in the control and free-radicals altered flame zones.

  9. Acoustically Forced Coaxial Hydrogen/Liquid Oxygen Jet Flames

    DTIC Science & Technology

    2016-05-15

    Briefing Charts 3. DATES COVERED (From - To) 25 April 2016 - 15 May 2016 4. TITLE AND SUBTITLE Acoustically Forced Coaxial Hydrogen / Liquid Oxygen Jet...area code) N/A Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std. 239.18 1 Acoustically Forced Coaxial Hydrogen / Liquid Oxygen Jet Flames...propellants be stored in condensed form – e.g., kerosene, liquid oxygen in rockets • Combustion systems can no longer be designed to meet modern

  10. Emissions of Parent, Nitro, and Oxygenated Polycyclic Aromatic Hydrocarbons from Residential Wood Combustion in Rural China

    PubMed Central

    SHEN, Guofeng; TAO, Shu; WEI, Siye; ZHANG, Yanyan; WANG, Rong; WANG, Bin; LI, Wei; SHEN, Huizhong; HUANG, Ye; CHEN, Yuanchen; CHEN, Han; YANG, Yifeng; WANG, Wei; WANG, Xilong; LIU, Wenxin; SIMONICH, Staci L. M.

    2012-01-01

    Residential wood combustion is one of the important sources of air pollution in developing countries. Among the pollutants emitted, parent polycyclic aromatic hydrocarbons (pPAHs) and their derivatives, including nitrated and oxygenated PAHs (nPAHs and oPAHs), are of concern because of their mutagenic and carcinogenic effects. In order to evaluate their impacts on regional air quality and human health, emission inventories, based on realistic emission factors (EFs), are needed. In this study, the EFs of 28 pPAHs (EFPAH28), 9 nPAHs (EFPAHn9) and 4 oPAHs (EFPAHo4) were measured for residential combustion of 27 wood fuels in rural China. The measured EFPAH28, EFPAHn9, and EFPAHo4 for brushwood were 86.7±67.6, 3.22±1.95×10−2, and 5.56±4.32 mg/kg, which were significantly higher than 12.7±7.0, 8.27±5.51×10−3, and 1.19±1.87 mg/kg for fuel wood combustion (p < 0.05). Sixteen U.S. EPA priority pPAHs contributed approximately 95% of the total of the 28 pPAHs measured. EFs of pPAHs, nPAHs, and oPAHs were positively correlated with one another. Measured EFs varied obviously depending on fuel properties and combustion conditions. The EFs of pPAHs, nPAHs, and oPAHs were significantly correlated with modified combustion efficiency and fuel moisture. Nitro-naphthalene and 9-fluorenone were the most abundant nPAHs and oPAHs identified. Both nPAHs and oPAHs showed relatively high tendencies to be present in the particulate phase than pPAHs due to their lower vapor pressures. The gas-particle partitioning of freshly emitted pPAHs, nPAHs and oPAHs was primarily controlled by organic carbon absorption. PMID:22765266

  11. Neutrophil Leukocyte: Combustive Microbicidal Action and Chemiluminescence

    PubMed Central

    Allen, Robert C.

    2015-01-01

    Neutrophil leukocytes protect against a varied and complex array of microbes by providing microbicidal action that is simple, potent, and focused. Neutrophils provide such action via redox reactions that change the frontier orbitals of oxygen (O2) facilitating combustion. The spin conservation rules define the symmetry barrier that prevents direct reaction of diradical O2 with nonradical molecules, explaining why combustion is not spontaneous. In burning, the spin barrier is overcome when energy causes homolytic bond cleavage producing radicals capable of reacting with diradical O2 to yield oxygenated radical products that further participate in reactive propagation. Neutrophil mediated combustion is by a different pathway. Changing the spin quantum state of O2 removes the symmetry restriction to reaction. Electronically excited singlet molecular oxygen (1O2 *) is a potent electrophilic reactant with a finite lifetime that restricts its radius of reactivity and focuses combustive action on the target microbe. The resulting exergonic dioxygenation reactions produce electronically excited carbonyls that relax by light emission, that is, chemiluminescence. This overview of neutrophil combustive microbicidal action takes the perspectives of spin conservation and bosonic-fermionic frontier orbital considerations. The necessary principles of particle physics and quantum mechanics are developed and integrated into a fundamental explanation of neutrophil microbicidal metabolism. PMID:26783542

  12. Hybrid lean premixing catalytic combustion system for gas turbines

    DOEpatents

    Critchley, Ian L.

    2003-12-09

    A system and method of combusting a hydrocarbon fuel is disclosed. The system combines the accuracy and controllability of an air staging system with the ultra-low emissions achieved by catalytic combustion systems without the need for a pre-heater. The result is a system and method that is mechanically simple and offers ultra-low emissions over a wide range of power levels, fuel properties and ambient operating conditions.

  13. Combustion system CFD modeling at GE Aircraft Engines

    NASA Technical Reports Server (NTRS)

    Burrus, D.; Mongia, H.; Tolpadi, Anil K.; Correa, S.; Braaten, M.

    1995-01-01

    This viewgraph presentation discusses key features of current combustion system CFD modeling capabilities at GE Aircraft Engines provided by the CONCERT code; CONCERT development history; modeling applied for designing engine combustion systems; modeling applied to improve fundamental understanding; CONCERT3D results for current production combustors; CONCERT3D model of NASA/GE E3 combustor; HYBRID CONCERT CFD/Monte-Carlo modeling approach; and future modeling directions.

  14. Combustion system CFD modeling at GE Aircraft Engines

    NASA Astrophysics Data System (ADS)

    Burrus, D.; Mongia, H.; Tolpadi, Anil K.; Correa, S.; Braaten, M.

    1995-03-01

    This viewgraph presentation discusses key features of current combustion system CFD modeling capabilities at GE Aircraft Engines provided by the CONCERT code; CONCERT development history; modeling applied for designing engine combustion systems; modeling applied to improve fundamental understanding; CONCERT3D results for current production combustors; CONCERT3D model of NASA/GE E3 combustor; HYBRID CONCERT CFD/Monte-Carlo modeling approach; and future modeling directions.

  15. Combustion system for hybrid solar fossil fuel receiver

    DOEpatents

    Mehos, Mark S.; Anselmo, Kenneth M.; Moreno, James B.; Andraka, Charles E.; Rawlinson, K. Scott; Corey, John; Bohn, Mark S.

    2004-05-25

    A combustion system for a hybrid solar receiver comprises a pre-mixer which combines air and fuel to form an air-fuel mixture. The mixture is introduced tangentially into a cooling jacket. A burner plenum is fluidically connected to the cooling jacket such that the burner plenum and the cooling jacket are arranged in thermal contact with one another. The air-fuel mixture flows through the cooling jacket cooling the burner plenum to reduce pre-ignition of the air-fuel mixture in the burner plenum. A combustion chamber is operatively associated with and open to the burner plenum to receive the air-fuel mixture from the burner plenum. An igniter is operatively positioned in the combustion chamber to combust the air-fuel mixture, releasing heat. A recuperator is operatively associated with the burner plenum and the combustion chamber and pre-heats the air-fuel mixture in the burner plenum with heat from the combustion chamber. A heat-exchanger is operatively associated and in thermal contact with the combustion chamber. The heat-exchanger provides heat for the hybrid solar receiver.

  16. Guide for Oxygen Component Qualification Tests

    NASA Technical Reports Server (NTRS)

    Bamford, Larry J.; Rucker, Michelle A.; Dobbin, Douglas

    1996-01-01

    Although oxygen is a chemically stable element, it is not shock sensitive, will not decompose, and is not flammable. Oxygen use therefore carries a risk that should never be overlooked, because oxygen is a strong oxidizer that vigorously supports combustion. Safety is of primary concern in oxygen service. To promote safety in oxygen systems, the flammability of materials used in them should be analyzed. At the NASA White Sands Test Facility (WSTF), we have performed configurational tests of components specifically engineered for oxygen service. These tests follow a detailed WSTF oxygen hazards analysis. The stated objective of the tests was to provide performance test data for customer use as part of a qualification plan for a particular component in a particular configuration, and under worst-case conditions. In this document - the 'Guide for Oxygen Component Qualification Tests' - we outline recommended test systems, and cleaning, handling, and test procedures that address worst-case conditions. It should be noted that test results apply specifically to: manual valves, remotely operated valves, check valves, relief valves, filters, regulators, flexible hoses, and intensifiers. Component systems are not covered.

  17. Analysis of pressure spectra measurements in a ducted combustion system

    NASA Astrophysics Data System (ADS)

    Miles, J. H.

    1980-11-01

    Combustion noise propagation in an operating ducted liquid fuel combustion system is studied in relation to the development of combustion noise prediction and suppression techniques. The presence of combustor emissions in the duct is proposed as the primary mechanism producing the attenuation and dispersion of combustion noise propagating in an operating liquid fuel combustion system. First, a complex mathematical model for calculating attenuation and dispersion taking into account mass transfer, heat transfer, and viscosity effects due to the presence of liquid fuel droplets or solid soot particles is discussed. Next, a simpler single parameter model for calculating pressure auto-spectra and cross-spectra which takes into account dispersion and attenuation due to heat transfer between solid soot particles and air is developed. Then, auto-spectra and cross-spectra obtained from internal pressure measurements in a combustion system consisting of a J-47 combustor can, a spool piece, and a long duct are presented. Last, analytical results obtained with the single parameter model are compared with the experimental measurements. The single parameter model results are shown to be in excellent agreement with the measurements.

  18. Characterisation of acoustic energy content in an experimental combustion chamber with and without external forcing

    NASA Astrophysics Data System (ADS)

    Webster, S.; Hardi, J.; Oschwald, M.

    2015-03-01

    The influence of injection conditions on rocket engine combustion stability is investigated for a sub-scale combustion chamber with shear coaxial injection elements and the propellant combination hydrogen-oxygen. The experimental results presented are from a series of tests conducted at subcritical and supercritical pressures for oxygen and for both ambient and cryogenic temperature hydrogen. The stability of the system is characterised by the root mean squared amplitude of dynamic combustion chamber pressure in the upper part of the acoustic spectrum relevant for high frequency combustion instabilities. Results are presented for both unforced and externally forced combustion chamber configurations. It was found that, for both the unforced and externally forced configurations, the injection velocity had the strongest influence on combustion chamber stability. Through the use of multivariate linear regression the influence of hydrogen injection temperature and hydrogen injection mass flow rate were best able to explain the variance in stability for dependence on injection velocity ratio. For unforced tests turbulent jet noise from injection was found to dominate the energy content of the signal. For the externally forced configuration a non-linear regression model was better able to predict the variance, suggesting the influence of non-linear behaviour. The response of the system to variation of injection conditions was found to be small; suggesting that the combustion chamber investigated in the experiment is highly stable.

  19. ISS Expedition 18 Fluids and Combustion Facility (FCF) Combustion Integration Rack (CIR) Passive Rack Isolation System (

    NASA Image and Video Library

    2009-01-05

    ISS018-E-017796 (5 Jan. 2009) --- Astronaut Sandra Magnus, Expedition 18 flight engineer, works on the Fluids and Combustion Facility (FCF) Combustion Integration Rack (CIR) Passive Rack Isolation System (PaRIS) in the Destiny laboratory of the International Space Station.

  20. Ash characterization in laboratory-scale oxy-coal combustor

    EPA Science Inventory

    Oxygen enriched coal (oxy-coal) combustion is a developing technology. During oxy-coal combustion, combustion air is separated and the coal is burned in a mixture of oxygen and recycled flue gas. The resulting effluent must be further processed before the C02 can be compressed, t...

  1. System and method for reducing combustion dynamics in a combustor

    DOEpatents

    Uhm, Jong Ho; Ziminsky, Willy Steve; Johnson, Thomas Edward; Srinivasan, Shiva; York, William David

    2016-11-29

    A system for reducing combustion dynamics in a combustor includes an end cap that extends radially across the combustor and includes an upstream surface axially separated from a downstream surface. A combustion chamber is downstream of the end cap, and tubes extend from the upstream surface through the downstream surface. Each tube provides fluid communication through the end cap to the combustion chamber. The system further includes means for reducing combustion dynamics in the combustor. A method for reducing combustion dynamics in a combustor includes flowing a working fluid through tubes that extend axially through an end cap that extends radially across the combustor and obstructing at least a portion of the working fluid flowing through a first set of the tubes.

  2. 76 FR 16646 - Circadian, Inc., Clean Energy Combustion, Inc. (n/k/a Clean Energy Combustion Systems, Inc...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-24

    .... (n/k/a Clean Energy Combustion Systems, Inc.), Collectible Concepts Group, Inc., Communitronics of America, Inc. (n/k/a RPM Advantage, Inc.), and ConSyGen, Inc., Order of Suspension of Trading March 22..., Inc. (n/k/a Clean Energy Combustion Systems, Inc.) because it has not filed any periodic reports since...

  3. Solid waste management of a chemical-looping combustion plant using Cu-based oxygen carriers.

    PubMed

    García-Labiano, Francisco; Gayán, Pilar; Adánez, Juan; De Diego, Luis F; Forero, Carmen R

    2007-08-15

    Waste management generated from a Chemical-Looping Combustion (CLC) plant using copper-based materials is analyzed by two ways: the recovery and recycling of the used material and the disposal of the waste. A copper recovery process coupled to the CLC plant is proposed to avoid the loss of active material generated by elutriation from the system. Solid residues obtained from a 10 kWth CLC prototype operated during 100 h with a CuO-Al2O3 oxygen carrier prepared by impregnation were used as raw material in the recovery process. Recovering efficiencies of approximately 80% were obtained in the process, where the final products were an eluate of Cu(NO3)2 and a solid. The eluate was used for preparation of new oxygen carriers by impregnation, which exhibited high reactivity for reduction and oxidation reactions as well as adequate physical and chemical properties to be used in a CLC plant. The proposed recovery process largely decreases the amount of natural resources (Cu and Al203) employed in a CLC power plant as well as the waste generated in the process. To determine the stability of the different solid streams during deposition in a landfill, these were characterized with respect to their leaching behavior according to the European Union normative. The solid residue finally obtained in the CLC plant coupled to the recovery process (composed by Al2O3 and CuAl2O4) can be classified as a stable nonreactive hazardous waste acceptable at landfills for nonhazardous wastes.

  4. Liquid Methane/Liquid Oxygen Propellant Conditioning Feed System (PCFS) Test Rigs

    NASA Technical Reports Server (NTRS)

    Skaff, A.; Grasl, S.; Nguyen, C.; Hockenberry S.; Schubert, J.; Arrington, L.; Vasek, T.

    2008-01-01

    As part of their Propulsion and Cryogenic Advanced Development (PCAD) program, NASA has embarked upon an effort to develop chemical rocket engines which utilize non-toxic, cryogenic propellants such as liquid oxygen (LO2) and liquid methane (LCH4). This effort includes the development and testing of a 100 lbf Reaction Control Engine (RCE) that will be used to evaluate the performance of a LO2/LCH4 rocket engine over a broad range of propellant temperatures and pressures. This testing will take place at NASA-Glenn Research Center's (GRC) Research Combustion Laboratory (RCL) test facility in Cleveland, OH, and is currently scheduled to begin in late 2008. While the initial tests will be performed at sea level, follow-on testing will be performed at NASA-GRC's Altitude Combustion Stand (ACS) for altitude testing. In support of these tests, Sierra Lobo, Inc. (SLI) has designed, developed, and fabricated two separate portable propellant feed systems under the Propellant Conditioning and Feed System (PCFS) task: one system for LCH4, and one for LO2. These systems will be capable of supplying propellants over a large range of conditions from highly densified to several hundred pounds per square inch (psi) saturated. This paper presents the details of the PCFS design and explores the full capability of these propellant feed systems.

  5. Unique phase identification of trimetallic copper iron manganese oxygen carrier using simultaneous differential scanning calorimetry/thermogravimetric analysis during chemical looping combustion reactions with methane

    DOE PAGES

    Benincosa, William; Siriwardane, Ranjani; Tian, Hanjing; ...

    2017-07-05

    Chemical looping combustion (CLC) is a promising combustion technology that generates heat and sequestration-ready carbon dioxide that is undiluted by nitrogen from the combustion of carbonaceous fuels with an oxygen carrier, or metal oxide. This process is highly dependent on the reactivity and stability of the oxygen carrier. The development of oxygen carriers remains one of the major barriers for commercialization of CLC. Synthetic oxygen carriers, consisting of multiple metal components, have demonstrated enhanced performance and improved CLC operation compared to single metal oxides. However, identification of the complex mixed metal oxide phases that form after calcination or during CLCmore » reactions has been challenging. Without an understanding of the dominant metal oxide phase, it is difficult to determine reaction parameters and the oxygen carrier reduction pathway, which are necessary for CLC reactor design. This is particularly challenging for complex multi-component oxygen carriers such as copper iron manganese oxide (CuFeMnO 4). This study aims to differentiate the unique phase formation of a highly reactive, complex trimetallic oxygen carrier, CuFeMnO 4, from its single and bimetallic counterparts using thermochemical and reaction data obtained from simultaneous differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) during temperature programmed reductions (TPR) with methane. DSC/TGA experiments during TPR with methane provides heat flow data and corresponding reaction rate data that can be used to determine reaction routes and mechanisms during methane reduction. Furthermore, non-isothermal TPR data provides the advantage of distinguishing reactions that may not be observable in isothermal analysis. The detailed thermochemical and reaction data, obtained during TPR with methane, distinguished a unique reduction pathway for CuFeMnO 4 that differed from its single and bimetallic counterparts. This is remarkable since X

  6. Unique phase identification of trimetallic copper iron manganese oxygen carrier using simultaneous differential scanning calorimetry/thermogravimetric analysis during chemical looping combustion reactions with methane

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Benincosa, William; Siriwardane, Ranjani; Tian, Hanjing

    Chemical looping combustion (CLC) is a promising combustion technology that generates heat and sequestration-ready carbon dioxide that is undiluted by nitrogen from the combustion of carbonaceous fuels with an oxygen carrier, or metal oxide. This process is highly dependent on the reactivity and stability of the oxygen carrier. The development of oxygen carriers remains one of the major barriers for commercialization of CLC. Synthetic oxygen carriers, consisting of multiple metal components, have demonstrated enhanced performance and improved CLC operation compared to single metal oxides. However, identification of the complex mixed metal oxide phases that form after calcination or during CLCmore » reactions has been challenging. Without an understanding of the dominant metal oxide phase, it is difficult to determine reaction parameters and the oxygen carrier reduction pathway, which are necessary for CLC reactor design. This is particularly challenging for complex multi-component oxygen carriers such as copper iron manganese oxide (CuFeMnO 4). This study aims to differentiate the unique phase formation of a highly reactive, complex trimetallic oxygen carrier, CuFeMnO 4, from its single and bimetallic counterparts using thermochemical and reaction data obtained from simultaneous differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) during temperature programmed reductions (TPR) with methane. DSC/TGA experiments during TPR with methane provides heat flow data and corresponding reaction rate data that can be used to determine reaction routes and mechanisms during methane reduction. Furthermore, non-isothermal TPR data provides the advantage of distinguishing reactions that may not be observable in isothermal analysis. The detailed thermochemical and reaction data, obtained during TPR with methane, distinguished a unique reduction pathway for CuFeMnO 4 that differed from its single and bimetallic counterparts. This is remarkable since X

  7. Effect of breathing oxygen-enriched air on exercise performance in patients with precapillary pulmonary hypertension: randomized, sham-controlled cross-over trial.

    PubMed

    Ulrich, Silvia; Hasler, Elisabeth D; Saxer, Stéphanie; Furian, Michael; Müller-Mottet, Séverine; Keusch, Stephan; Bloch, Konrad E

    2017-04-14

    The purpose of the current trial was to test the hypothesis that breathing oxygen-enriched air increases exercise performance of patients with pulmonary arterial or chronic thrombo-embolic pulmonary hypertension (PAH/CTEPH) and to investigate involved mechanisms. Twenty-two patients with PAH/CTEPH, eight women, means ± SD 61 ± 14 years, resting mPAP 35 ± 9mmHg, PaO2 ambient air >7.3 kPa, underwent four bicycle ergospirometries to exhaustion on different days, while breathing oxygen-enriched (FiO2 0.50, hyperoxia) or ambient air (FiO2 0.21, normoxia) using progressively increased or constant load protocols (with 75% maximal work rate under FiO2 0.21), according to a randomized, sham-controlled, single-blind, cross-over design. ECG, pulmonary gas-exchange, arterial blood gases, cerebral and quadriceps muscle tissue oxygenation (CTO and QMTO) by near-infrared spectroscopy were measured. In ramp exercise, maximal work rate increased from 113 ± 38 W with normoxia to 132 ± 48 W with hyperoxia, mean difference 19.7 (95% CI 10.5-28.9) W, P < 0.001. Constant load exercise endurance increased from 571 ± 443 to 1242 ± 514 s, mean difference 671 (95% CI 392-951) s, P < 0.001. At end-exercise with hyperoxia PaO2, CTO, QMTO, and PaCO2 were increased, and ventilatory equivalents for CO2 were reduced while the physiological dead space/tidal volume ratio remained unchanged. In patients with PAH/CTEPH, breathing oxygen-enriched air provides major increases in exercise performance. This is related to an improved arterial oxygenation that promotes oxygen availability in muscles and brain and to a reduction of the excessive ventilatory response to exercise thereby enhancing ventilatory efficiency. Patients with PAH/CTEPH may therefore benefit from oxygen therapy during daily physical activities and training. clinicaltrials.gov Identifier: NCT01748474. Published on behalf of the European Society of Cardiology. All rights reserved. © The

  8. Thermodynamic Analysis of Oxygen-Enriched Direct Smelting of Jamesonite Concentrate

    NASA Astrophysics Data System (ADS)

    Zhang, Zhong-Tang; Dai, Xi; Zhang, Wen-Hai

    2017-12-01

    Thermodynamic analysis of oxygen-enriched direct smelting of jamesonite concentrate is reported in this article. First, the occurrence state of lead, antimony and other metallic elements in the smelting process was investigated theoretically. Then, the verification test was carried out. The results indicate that lead and antimony mainly exist in the alloy in the form of metallic lead and metallic antimony. Simultaneously, lead and antimony were also oxidized into the slag in the form of lead-antimony oxide. Iron and copper could be oxidized into the slag in the form of oxides in addition to combining with antimony in the alloy, while zinc was mainly oxidized into the slag in the form of zinc oxide. The verification test indicates that the main phases in the alloy contain metallic lead, metallic antimony and a small amount of Cu2Sb, FeSb2 intermetallic compounds, and the slag is mainly composed of kirschsteinite, fayalite and zinc oxide, in agreement with the thermodynamic analysis.

  9. Fuel-rich catalytic combustion: A soot-free technique for in situ hydrogen-like enrichment

    NASA Technical Reports Server (NTRS)

    Brabbs, T. A.; Olson, S. L.

    1985-01-01

    An experimental program on the catalytic oxidation of iso-octane demonstrated the feasibility of the two-stage combustion system for reducing particulate emissions. With a fuel-rich (phi = 4.8 to 7.8) catalytic combustion preburner as the first stage the combustion process was soot free at reactor outlet temperatures of 1200 K or less. Although soot was not measured directly, its absence was indicated. Reaction products collected at two positions downstream of the catalyst bed were analyzed on a gas chromatograph. Comparison of these products indicated that pyrolysis of the larger molecules continued along the drift tube and that benzene formation was a gas-phase reaction. The effective hydrogen-carbon ratio calculated from the reaction products increased by 20 to 68 percent over the range of equivalence ratios tested. The catalytic partial oxidation process also yielded a large number of smaller-containing molecules. The fraction of fuel carbon in compounds having two or fewer carbon atoms ranged from 30 percent at 1100 K to 80 percent at 1200 K.

  10. Alkali injection system with controlled CO.sub.2 /O.sub.2 ratios for combustion of coal

    DOEpatents

    Berry, Gregory F.

    1988-01-01

    A high temperature combustion process for an organic fuel containing sulfur n which the nitrogen of air is replaced by carbon dioxide for combination with oxygen with the ratio of CO.sub.2 /O.sub.2 being controlled to generate combustion temperatures above 2000 K. for a gas-gas reaction with SO.sub.2 and an alkali metal compound to produce a sulfate and in which a portion of the carbon-dioxide rich gas is recycled for mixing with oxygen and/or for injection as a cooling gas upstream from heating exchangers to limit fouling of the exchangers, with the remaining carbon-dioxide rich gas being available as a source of CO.sub.2 for oil recovery and other purposes.

  11. 21 CFR 173.350 - Combustion product gas.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... FOR HUMAN CONSUMPTION (CONTINUED) SECONDARY DIRECT FOOD ADDITIVES PERMITTED IN FOOD FOR HUMAN CONSUMPTION Specific Usage Additives § 173.350 Combustion product gas. The food additive combustion product... this section for the purpose of removing and displacing oxygen in accordance with the following...

  12. 21 CFR 173.350 - Combustion product gas.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... FOR HUMAN CONSUMPTION (CONTINUED) SECONDARY DIRECT FOOD ADDITIVES PERMITTED IN FOOD FOR HUMAN CONSUMPTION Specific Usage Additives § 173.350 Combustion product gas. The food additive combustion product... this section for the purpose of removing and displacing oxygen in accordance with the following...

  13. 21 CFR 173.350 - Combustion product gas.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... FOR HUMAN CONSUMPTION (CONTINUED) SECONDARY DIRECT FOOD ADDITIVES PERMITTED IN FOOD FOR HUMAN CONSUMPTION Specific Usage Additives § 173.350 Combustion product gas. The food additive combustion product... this section for the purpose of removing and displacing oxygen in accordance with the following...

  14. 21 CFR 173.350 - Combustion product gas.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... FOR HUMAN CONSUMPTION (CONTINUED) SECONDARY DIRECT FOOD ADDITIVES PERMITTED IN FOOD FOR HUMAN CONSUMPTION Specific Usage Additives § 173.350 Combustion product gas. The food additive combustion product... this section for the purpose of removing and displacing oxygen in accordance with the following...

  15. Annual Report: DOE Advanced Combustion Systems & Fuels R&D; Light-Duty Diesel Combustion

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Busch, Stephen

    Despite compliance issues in previous years, automakers have demonstrated that the newest generation of diesel power trains are capable of meeting all federal and state regulations (EPA, 2016). Diesels continue to be a cost-effective, efficient, powerful propulsion source for many light- and medium-duty vehicle applications (Martec, 2016). Even modest reductions in the fuel consumption of light- and medium duty diesel vehicles in the U.S. will eliminate millions of tons of CO2 emissions per year. Continued improvement of diesel combustion systems will play an important role in reducing fleet fuel consumption, but these improvements will require an unprecedented scientific understanding ofmore » how changes in engine design and calibration affect the mixture preparation, combustion, and pollutant formation processes that take place inside the cylinder. The focus of this year’s research is to provide insight into the physical mechanisms responsible for improved thermal efficiency observed with a stepped-lip piston. Understanding how piston design can influence efficiency will help engineers develop and optimize new diesel combustion systems.« less

  16. Highly Efficient Oxygen-Storage Material with Intrinsic Coke Resistance for Chemical Looping Combustion-Based CO2 Capture.

    PubMed

    Imtiaz, Qasim; Kurlov, Alexey; Rupp, Jennifer Lilia Marguerite; Müller, Christoph Rüdiger

    2015-06-22

    Chemical looping combustion (CLC) and chemical looping with oxygen uncoupling (CLOU) are emerging thermochemical CO2 capture cycles that allow the capture of CO2 with a small energy penalty. Here, the development of suitable oxygen carrier materials is a key aspect to transfer these promising concepts to practical installations. CuO is an attractive material for CLC and CLOU because of its high oxygen-storage capacity (20 wt %), fast reaction kinetics, and high equilibrium partial pressure of oxygen at typical operating temperatures (850-1000 °C). However, despite its promising characteristics, its low Tammann temperature requires the development of new strategies to phase-stabilize CuO-based oxygen carriers. In this work, we report a strategy based on stabilization by co-precipitated ceria (CeO2-x ), which allowed us to increase the oxygen capacity, coke resistance, and redox stability of CuO-based oxygen carriers substantially. The performance of the new oxygen carriers was evaluated in detail and compared to the current state-of-the-art materials, that is, Al2 O3 -stabilized CuO with similar CuO loadings. We also demonstrate that the higher intrinsic oxygen uptake, release, and mobility in CeO2-x -stabilized CuO leads to a three times higher carbon deposition resistance compared to that of Al2 O3 -stabilized CuO. Moreover, we report a high cyclic stability without phase intermixing for CeO2-x -supported CuO. This was accompanied by a lower reduction temperature compared to state-of-the-art Al2 O3 -supported CuO. As a result of its high resistance towards carbon deposition and fast oxygen uncoupling kinetics, CeO2-x -stabilized CuO is identified as a very promising material for CLC- and CLOU-based CO2 capture architectures. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Predictive Evaluations of Oxygen-Rich Hydrocarbon Combustion Gas-Centered Swirl Coaxial Injectors using a Flamelet-Based 3-D CFD Simulation Approach

    NASA Technical Reports Server (NTRS)

    Richardson, Brian R.; Braman, Kalem; West, Jeff

    2016-01-01

    NASA Marshall Space Flight Center (MSFC) has embarked upon a joint project with the Air Force to improve the state-of-the-art of space application combustion device design and operational understanding. One goal of the project is to design, build and hot-fire test a 40,000 pound-thrust Oxygen/Rocket Propellant-2 (RP-2) Oxygen-Rich staged engine at MSFC. The overall project goals afford the opportunity to test multiple different injector designs and experimentally evaluate the any effect on the engine performance and combustion dynamics. To maximize the available test resources and benefits, pre-test, combusting flow, Computational Fluid Dynamics (CFD) analysis was performed on the individual injectors to guide the design. The results of the CFD analysis were used to design the injectors for specific, targeted fluid dynamic features and the analysis results also provided some predictive input for acoustic and thermal analysis of the main Thrust Chamber Assembly (TCA). MSFC has developed and demonstrated the ability to utilize a computationally efficient, flamelet-based combustion model to guide the pre-test design of single-element Gas Centered Swirl Coaxial (GCSC) injectors. Previous, Oxygen/RP-2 simulation models utilizing the Loci-STREAM flow solver, were validated using single injector test data from the EC-1 Air Force test facility. The simulation effort herein is an extension of the validated, CFD driven, single-injector design approach applied to single injectors which will be part of a larger engine array. Time-accurate, Three-Dimensional, CFD simulations were performed for five different classes of injector geometries. Simulations were performed to guide the design of the injector to achieve a variety of intended performance goals. For example, two GCSC injectors were designed to achieve stable hydrodynamic behavior of the propellant circuits while providing the largest thermal margin possible within the design envelope. While another injector was designed

  18. Droplet Combustion Experiments Aboard the International Space Station

    NASA Astrophysics Data System (ADS)

    Dietrich, Daniel L.; Nayagam, Vedha; Hicks, Michael C.; Ferkul, Paul V.; Dryer, Frederick L.; Farouk, Tanvir; Shaw, Benjamin D.; Suh, Hyun Kyu; Choi, Mun Y.; Liu, Yu Cheng; Avedisian, C. Thomas; Williams, Forman A.

    2014-10-01

    This paper summarizes the first results from isolated droplet combustion experiments performed on the International Space Station (ISS). The long durations of microgravity provided in the ISS enable the measurement of droplet and flame histories over an unprecedented range of conditions. The first experiments were with heptane and methanol as fuels, initial droplet droplet diameters between 1.5 and 5.0 m m, ambient oxygen mole fractions between 0.1 and 0.4, ambient pressures between 0.7 and 3.0 a t m and ambient environments containing oxygen and nitrogen diluted with both carbon dioxide and helium. The experiments show both radiative and diffusive extinction. For both fuels, the flames exhibited pre-extinction flame oscillations during radiative extinction with a frequency of approximately 1 H z. The results revealed that as the ambient oxygen mole fraction was reduced, the diffusive-extinction droplet diameter increased and the radiative-extinction droplet diameter decreased. In between these two limiting extinction conditions, quasi-steady combustion was observed. Another important measurement that is related to spacecraft fire safety is the limiting oxygen index (LOI), the oxygen concentration below which quasi-steady combustion cannot be supported. This is also the ambient oxygen mole fraction for which the radiative and diffusive extinction diameters become equal. For oxygen/nitrogen mixtures, the LOI is 0.12 and 0.15 for methanol and heptane, respectively. The LOI increases to approximately 0.14 (0.14 O 2/0.56 N 2/0.30 C O 2) and 0.17 (0.17 O 2/0.63 N 2/0.20 C O 2) for methanol and heptane, respectively, for ambient environments that simulated dispersing an inert-gas suppressant (carbon dioxide) into a nominally air (1.0 a t m) ambient environment. The LOI is approximately 0.14 and 0.15 for methanol and heptane, respectively, when helium is dispersed into air at 1 atm. The experiments also showed unique burning behavior for large heptane droplets. After the

  19. Preburner of Staged Combustion Rocket Engine

    NASA Technical Reports Server (NTRS)

    Yost, M. C.

    1978-01-01

    A regeneratively cooled LOX/hydrogen staged combustion assembly system with a 400:1 expansion area ratio nozzle utilizing an 89,000 Newton (20,000 pound) thrust regeneratively cooled thrust chamber and 175:1 tubular nozzle was analyzed, assembled, and tested. The components for this assembly include two spark/torch oxygen-hydrogen igniters, two servo-controlled LOX valves, a preburner injector, a preburner combustor, a main propellant injector, a regeneratively cooled combustion chamber, a regeneratively cooled tubular nozzle with an expansion area ratio of 175:1, an uncooled heavy-wall steel nozzle with an expansion area ratio of 400:1, and interconnecting ducting. The analytical effort was performed to optimize the thermal and structural characteristics of each of the new components and the ducting, and to reverify the capabilities of the previously fabricated components. The testing effort provided a demonstration of the preburner/combustor chamber operation, chamber combustion efficiency and stability, and chamber and nozzle heat transfer.

  20. Thermal Model of the Promoted Combustion Test

    NASA Technical Reports Server (NTRS)

    Jones, Peter D.

    1996-01-01

    Flammability of metals in high pressure, pure oxygen environments, such as rocket engine turbopumps, is commonly evaluated using the Promoted Combustion Test (PCT). The PCT emphasizes the ability of an ignited material to sustain combustion, as opposed to evaluating the sample's propensity to ignite in the first place. A common arrangement is a rod of the sample material hanging in a chamber in which a high pressure, pure oxygen environment is maintained. An igniter of some energetically combusting material is fixed to the bottom of the rod and fired. This initiates combustion, and the sample burns and melts at its bottom tip. A ball of molten material forms, and this ball detaches when it grows too large to be supported by surface tension with the rod. In materials which do not sustain combustion, the combustion then extinguishes. In materials which do sustain combustion, combustion re-initiates from molten residue left on the bottom of the rod, and the melt ball burns and grows until it detaches again. The purpose of this work is development of a PCT thermal simulation model, detailing phase change, melt detachment, and the several heat transfer modes. Combustion is modeled by a summary rate equation, whose parameters are identified by comparison to PCT results. The sensitivity of PCT results to various physical and geometrical parameters is evaluated. The identified combustion parameters may be used in design of new PCT arrangements, as might be used for flammability assessment in flow-dominated environments. The Haynes 214 nickel-based superalloy, whose PCT results are applied here, burns heterogeneously (fuel and oxidizer are of different phases; combustion takes place on the fuel surface). Heterogeneous combustion is not well understood. (In homogeneous combustion, the metal vaporizes, and combustion takes place in an analytically treatable cloud above the surface). Thermal modeling in heterogeneous combustion settings provides a means for linking test

  1. Microgravity combustion discipline working group summary of requirements for noncontact temperature measurements

    NASA Technical Reports Server (NTRS)

    Sacksteder, Kurt

    1988-01-01

    Current efforts of the Microgravity Combustion Working Group are summarized and the temperature measurement requirements for the combustion studies are defined. Many of the combustion systems that are studied in the low gravity environment are near-limit systems, that is, systems that are acting near the limit of flammability in terms of oxygen concentration or fuel concentration. Systems of this type are normally weak in the sense that there is a delicate balance between the heat released in the flame and the heat required to sustain the flame. Intrusive or perturbative temperature measurement probes can be inaccurate in these situations and in the limiting case extinguish the flame. Noncontact techniques then become the only way to obtain the required measurements. Noncontact measurement requirements for each of the three thermodynamic phases are described in terms of spatial and temporal resolution and temperature range.

  2. Characteristic Study of Shenmu Bituminous Coal Combustion with Online TG-MS-FTIR

    NASA Astrophysics Data System (ADS)

    Pan, Guanfu

    2018-01-01

    The combustion characteristics of Shenmu bituminous pulverized coal (SBC) were comprehensively investigated with a combined TG-MS-FTIR system by considering the effect of particle size, heating rate and total flowrate. The combustion products were accurately quantified by normalization and numerical analysis of MS results. The results indicate that the decrease of the particle size, heating rate and total flowrate result in lower ignition and burnout temperatures. The activation energy tends to be lower with smaller particle size, lower heating rate and total flowrate. The MS and FTIR results demonstrate that lower concentrations of different products, such as NO, NO2, HCN, CH4 and SO2 were produced with smaller particle size, slower heating rate and lower total flowrate. The decrease of particle size would lead to more contact area with oxygen and slower heating rate could provide more sufficient time for the diffusion. High total flowrate would reduce the oxygen adsorbability on the coal particle surface and shorten the residence time of oxygen, which makes the ignition difficult to occur. This work will guide to understand the combustion kinetics of pulverized coals and be beneficial to control the formation of pollutants.

  3. National Combustion Code Used To Study the Hydrogen Injector Design for Gas Turbines

    NASA Technical Reports Server (NTRS)

    Iannetti, Anthony C.; Norris, Andrew T.; Shih, Tsan-Hsing

    2005-01-01

    Hydrogen, in the gas state, has been proposed to replace Jet-A (the fuel used for commercial jet engines) as a fuel for gas turbine combustion. For the combustion of hydrogen and oxygen only, water is the only product and the main greenhouse gas, carbon dioxide, is not produced. This is an obvious benefit of using hydrogen as a fuel. The situation is not as simple when air replaces oxygen in the combustion process. (Air is mainly a mixture of oxygen, nitrogen, and argon. Other components comprise a very small part of air and will not be mentioned.) At the high temperatures found in the combustion process, oxygen reacts with nitrogen, and this produces nitrogen oxide compounds, or NOx--the main component of atmospheric smog. The production of NOx depends mainly on two variables: the temperature at which combustion occurs, and the length of time that the products of combustion stay, or reside, in the combustor. Starting from a lean (excess air) air-to-fuel ratio, the goal of this research was to minimize hot zones caused by incomplete premixing and to keep the residence time short while producing a stable flame. The minimization of these two parameters will result in low- NOx hydrogen combustion.

  4. Distributed combustion in a cyclonic burner

    NASA Astrophysics Data System (ADS)

    Sorrentino, Giancarlo; Sabia, Pino; de Joannon, Mara; Cavaliere, Antonio; Ragucci, Raffaele

    2017-11-01

    Distributed combustion regime occurs in several combustion technologies were efficient and environmentally cleaner energy conversion are primary tasks. For such technologies (MILD, LTC, etc…), working temperatures are enough low to boost the formation of several classes of pollutants, such as NOx and soot. To access this temperature range, a significant dilution as well as preheating of reactants is required. Such conditions are usually achieved by a strong recirculation of exhaust gases that simultaneously dilute and pre-heat the fresh reactants. However, the intersection of low combustion temperatures and highly diluted mixtures with intense pre-heating alters the evolution of the combustion process with respect to traditional flames, leading to significant features such as uniformity and distributed ignition. The present study numerically characterized the turbulence-chemistry and combustion regimes of propane/oxygen mixtures, highly diluted in nitrogen, at atmospheric pressure, in a cyclonic combustor under MILD Combustion operating conditions. The velocity and mixing fields were obtained using CFD with focus on mean and fluctuating quantities. The flow-field information helped differentiate between the impact of turbulence levels and dilution ones. The integral length scale along with the fluctuating velocity is critical to determine Damköhler and Karlovitz numbers. Together these numbers identify the combustion regime at which the combustor is operating. This information clearly distinguishes between conventional flames and distributed combustion. The results revealed that major controllers of the reaction regime are dilution and mixing levels; both are significantly impacted by lowering oxygen concentration through entrainment of hot reactive species from within the combustor, which is important in distributed combustion. Understanding the controlling factors of distributed regime is critical for the development and deployment of these novel combustion

  5. On-Line Measurement of Heat of Combustion of Gaseous Hydrocarbon Fuel Mixtures

    NASA Technical Reports Server (NTRS)

    Sprinkle, Danny R.; Chaturvedi, Sushil K.; Kheireddine, Ali

    1996-01-01

    A method for the on-line measurement of the heat of combustion of gaseous hydrocarbon fuel mixtures has been developed and tested. The method involves combustion of a test gas with a measured quantity of air to achieve a preset concentration of oxygen in the combustion products. This method involves using a controller which maintains the fuel (gas) volumetric flow rate at a level consistent with the desired oxygen concentration in the combustion products. The heat of combustion is determined form a known correlation with the fuel flow rate. An on-line computer accesses the fuel flow data and displays the heat of combustion measurement at desired time intervals. This technique appears to be especially applicable for measuring heats of combustion of hydrocarbon mixtures of unknown composition such as natural gas.

  6. Determination of fluorine, chlorine and bromine in household products by means of oxygen bomb combustion and ion chromatography.

    PubMed

    Zhang, Shuai; Zhao, Tianbo; Wang, Jia; Qu, Xiaoling; Chen, Wei; Han, Yin

    2013-01-01

    A method for routine determination of fluorine, chlorine and bromine in household products was developed and validated. In this work, halogen analyses were made based on oxygen bomb combustion followed by ion chromatography (IC). The chromatographic analysis was performed by an IonPac AS19 hydroxide-selective anion-exchange column, a reagent free ion chromatograph eluent generator and an anion self-regenerating suppressor in 10 min. The response was linear (r ≥ 0.9995) in the entire investigated domain. The limit of detection for the halogens was in the range of 2 to 9 × 10(-3) mg/L and the limit of quantification was lower than 8 mg/Kg with 20 µL of injection volume. The certified reference material of ERM-EC 681k was pretreated using an oxygen bomb combustion procedure to demonstrate the precision of the proposed method. The quantitative analysis results obtained by IC for the target elements were 797 ± 9 mg/Kg chlorine and 786 ± 25 mg/Kg bromine, which were in good agreement with the certified values of 800 ± 4 mg/Kg chlorine, 770 ± 5 mg/Kg bromine for ERM-EC 681k, respectively. This validated method was successfully applied for the analysis of fluorine, chlorine and bromine in household product samples, and the variation of halogen contained among the tested samples was remarkable.

  7. Simulation of Combustion Systems with Realistic g-jitter

    NASA Technical Reports Server (NTRS)

    Mell, William E.; McGrattan, Kevin B.; Baum, Howard R.

    2003-01-01

    In this project a transient, fully three-dimensional computer simulation code was developed to simulate the effects of realistic g-jitter on a number of combustion systems. The simulation code is capable of simulating flame spread on a solid and nonpremixed or premixed gaseous combustion in nonturbulent flow with simple combustion models. Simple combustion models were used to preserve computational efficiency since this is meant to be an engineering code. Also, the use of sophisticated turbulence models was not pursued (a simple Smagorinsky type model can be implemented if deemed appropriate) because if flow velocities are large enough for turbulence to develop in a reduced gravity combustion scenario it is unlikely that g-jitter disturbances (in NASA's reduced gravity facilities) will play an important role in the flame dynamics. Acceleration disturbances of realistic orientation, magnitude, and time dependence can be easily included in the simulation. The simulation algorithm was based on techniques used in an existing large eddy simulation code which has successfully simulated fire dynamics in complex domains. A series of simulations with measured and predicted acceleration disturbances on the International Space Station (ISS) are presented. The results of this series of simulations suggested a passive isolation system and appropriate scheduling of crew activity would provide a sufficiently "quiet" acceleration environment for spherical diffusion flames.

  8. System and method for cooling a combustion gas charge

    DOEpatents

    Massey, Mary Cecelia; Boberg, Thomas Earl

    2010-05-25

    The present invention relates to a system and method for cooling a combustion gas charge prior. The combustion gas charge may include compressed intake air, exhaust gas, or a mixture thereof. An evaporator is provided that may then receive a relatively high temperature combustion gas charge and discharge at a relatively lower temperature. The evaporator may be configured to operate with refrigeration cycle components and/or to receive a fluid below atmospheric pressure as the phase-change cooling medium.

  9. Simulation of low temperature combustion mechanism of different combustion-supporting agents in close-coupled DOC and DPF system.

    PubMed

    Jiao, Penghao; Li, Zhijun; Li, Qiang; Zhang, Wen; He, Li; Wu, Yue

    2018-07-01

    In the coupled Diesel Oxidation Catalyst (DOC) and Diesel Particular Filter (DPF) system, soot cannot be completely removed by only using the passive regeneration. And DPF active regeneration is necessary. The research method in this paper is to spray different kinds of combustion-supporting agents to the DOC in the front of the DPF. Therefore, the low temperature combustion mechanism of different kinds of combustion-supporting agents in DOC was studied, in order to grasp the law of combustion in DOC, and the influence of follow-up emission on DPF removal of soot. During the study, CH 4 H 2 mixture and diesel (n-heptane + toluene) were used as combustion-supporting agents respectively. The simplified mechanisms of two kinds of gas mixtures used as the combustion-supporting agents in DPF have been constructed and testified in the paper. In this paper, the combustion and emission conditions of the two combustion-supporting agents were analyzed so as to meet the practical requirements of different working conditions. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  10. Performance and Stability Analyses of Rocket Thrust Chambers with Oxygen/Methane Propellants

    NASA Technical Reports Server (NTRS)

    Hulka, James R.; Jones, Gregg W.

    2010-01-01

    Liquid rocket engines using oxygen and methane propellants are being considered by the National Aeronautics and Space Administration (NASA) for future in-space vehicles. This propellant combination has not been previously used in flight-qualified engine systems developed by NASA, so limited test data and analysis results are available at this stage of early development. As part of activities for the Propulsion and Cryogenic Advanced Development (PCAD) project funded under the Exploration Technology Development Program, the NASA Marshall Space Flight Center (MSFC) has been evaluating capability to model combustion performance and stability for oxygen and methane propellants. This activity has been proceeding for about two years and this paper is a summary of results to date. Hot-fire test results of oxygen/methane propellant rocket engine combustion devices for the modeling investigations have come from several sources, including multi-element injector tests with gaseous methane from the 1980s, single element tests with gaseous methane funded through the Constellation University Institutes Program, and multi-element injector tests with both gaseous and liquid methane conducted at the NASA MSFC funded by PCAD. For the latter, test results of both impinging and coaxial element injectors using liquid oxygen and liquid methane propellants are included. Configurations were modeled with two one-dimensional liquid rocket combustion analysis codes, the Rocket Combustor Interactive Design and Analysis code and the Coaxial Injector Combustion Model. Special effort was focused on how these codes can be used to model combustion and performance with oxygen/methane propellants a priori, and what anchoring or calibrating features need to be applied, improved or developed in the future. Low frequency combustion instability (chug) occurred, with frequencies ranging from 150 to 250 Hz, with several multi-element injectors with liquid/liquid propellants, and was modeled using

  11. 46 CFR 62.35-35 - Starting systems for internal-combustion engines.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 2 2013-10-01 2013-10-01 false Starting systems for internal-combustion engines. 62.35-35 Section 62.35-35 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE... Starting systems for internal-combustion engines. The starting systems for propulsion engines and for prime...

  12. 46 CFR 62.35-35 - Starting systems for internal-combustion engines.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 2 2014-10-01 2014-10-01 false Starting systems for internal-combustion engines. 62.35-35 Section 62.35-35 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE... Starting systems for internal-combustion engines. The starting systems for propulsion engines and for prime...

  13. 46 CFR 62.35-35 - Starting systems for internal-combustion engines.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Starting systems for internal-combustion engines. 62.35-35 Section 62.35-35 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE... Starting systems for internal-combustion engines. The starting systems for propulsion engines and for prime...

  14. 46 CFR 62.35-35 - Starting systems for internal-combustion engines.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 2 2011-10-01 2011-10-01 false Starting systems for internal-combustion engines. 62.35-35 Section 62.35-35 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE... Starting systems for internal-combustion engines. The starting systems for propulsion engines and for prime...

  15. 46 CFR 62.35-35 - Starting systems for internal-combustion engines.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 2 2012-10-01 2012-10-01 false Starting systems for internal-combustion engines. 62.35-35 Section 62.35-35 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE... Starting systems for internal-combustion engines. The starting systems for propulsion engines and for prime...

  16. Combustion systems and power plants incorporating parallel carbon dioxide capture and sweep-based membrane separation units to remove carbon dioxide from combustion gases

    DOEpatents

    Wijmans, Johannes G [Menlo Park, CA; Merkel, Timothy C [Menlo Park, CA; Baker, Richard W [Palo Alto, CA

    2011-10-11

    Disclosed herein are combustion systems and power plants that incorporate sweep-based membrane separation units to remove carbon dioxide from combustion gases. In its most basic embodiment, the invention is a combustion system that includes three discrete units: a combustion unit, a carbon dioxide capture unit, and a sweep-based membrane separation unit. In a preferred embodiment, the invention is a power plant including a combustion unit, a power generation system, a carbon dioxide capture unit, and a sweep-based membrane separation unit. In both of these embodiments, the carbon dioxide capture unit and the sweep-based membrane separation unit are configured to be operated in parallel, by which we mean that each unit is adapted to receive exhaust gases from the combustion unit without such gases first passing through the other unit.

  17. Oxygen transport membrane based advanced power cycle with low pressure synthesis gas slip stream

    DOEpatents

    Kromer, Brian R.; Litwin, Michael M.; Kelly, Sean M.

    2016-09-27

    A method and system for generating electrical power in which a high pressure synthesis gas stream generated in a gasifier is partially oxidized in an oxygen transport membrane based reactor, expanded and thereafter, is combusted in an oxygen transport membrane based boiler. A low pressure synthesis gas slip stream is split off downstream of the expanders and used as the source of fuel in the oxygen transport membrane based partial oxidation reactors to allow the oxygen transport membrane to operate at low fuel pressures with high fuel utilization. The combustion within the boiler generates heat to raise steam to in turn generate electricity by a generator coupled to a steam turbine. The resultant flue gas can be purified to produce a carbon dioxide product.

  18. Premixed flame propagation in combustible particle cloud mixtures

    NASA Technical Reports Server (NTRS)

    Seshadri, K.; Yang, B.

    1993-01-01

    The structures of premixed flames propagating in combustible systems, containing uniformly distributed volatile fuel particles, in an oxidizing gas mixtures is analyzed. The experimental results show that steady flame propagation occurs even if the initial equivalence ratio of the combustible mixture based on the gaseous fuel available in the particles, phi(u) is substantially larger than unity. A model is developed to explain these experimental observations. In the model it is presumed that the fuel particles vaporize first to yield a gaseous fuel of known chemical composition which then reacts with oxygen in a one-step overall process. It is shown that the interplay of vaporization kinetics and oxidation process, can result in steady flame propagation in combustible mixtures where the value of phi(u) is substantially larger than unity. This prediction is in agreement with experimental observations.

  19. Fuelling the palaeoatmospheric oxygen debate: how much atmospheric oxygen is required for ignition and propagation of smouldering fires?

    NASA Astrophysics Data System (ADS)

    Belcher, Claire M.; Hadden, Rory; McElwain, Jennifer C.; Rein, Guillermo

    2010-05-01

    Fire is a natural process integral to ecosystems at a wide range of temporal and spatial scales and is a key driver of change in the Earth system. Fire has been a major influence on Earth's systems since the Carboniferous. Whilst, climate is considered the ultimate control on global vegetation, fire is now known to play a key role in determining vegetation structure and composition, such that many of the world's ecosystems can be considered fire-dependant. Products of fire include chars, soots and aromatic hydrocarbon species all of which can be traced in ancient through to modern sediments. Atmospheric oxygen has played a key role in the development of life on Earth, with the rise of oxygen in the Precambrian being closely linked to biological evolution. Variations in the concentration of atmospheric oxygen throughout the Phanerozoic are predicted from models based on geochemical cycling of carbon and sulphur. Such models predict that low atmospheric oxygen concentrations prevailed in the Mesozoic (251-65ma) and have been hypothesised to be the primary driver of at least two of the ‘big five' mass extinction events in the Phanerozoic. Here we assess the levels of atmospheric oxygen required to ignite a fire and infer the likely levels of atmospheric oxygen to support smouldering combustion. Smouldering fire dynamics and its effects on ecosystems are very different from flaming fires. Smouldering fires propagate slowly, are usually low in temperature and represent a flameless form of combustion. These fires creep through organic layers of forest ground and peat lands and are responsible for a large fraction of the total biomass consumed in wildfires globally and are also a major contributor of carbon dioxide to the atmosphere. Once ignited, they can persist for long periods of time (months, years) spreading over very extensive areas of forest and deep into soil. Smouldering fires are therefore, the oldest continuously burning fires on Earth. We have combined

  20. Apparent Km of mitochondria for oxygen computed from Vmax measured in permeabilized muscle fibers is lower in water enriched in oxygen by electrolysis than injection.

    PubMed

    Zoll, Joffrey; Bouitbir, Jamal; Sirvent, Pascal; Klein, Alexis; Charton, Antoine; Jimenez, Liliana; Péronnet, François R; Geny, Bernard; Richard, Ruddy

    2015-01-01

    It has been suggested that oxygen (O2) diffusion could be favored in water enriched in O2 by a new electrolytic process because of O2 trapping in water superstructures (clathrates), which could reduce the local pressure/content relationships for O2 and facilitate O2 diffusion along PO2 gradients. Mitochondrial respiration was compared in situ in saponin-skinned fibers isolated from the soleus muscles of Wistar rats, in solution enriched in O2 by injection or the electrolytic process 1) at an O2 concentration decreasing from 240 µmol/L to 10 µmol/L (132 mmHg to 5 mmHg), with glutamate-malate or N, N, N', N'-tetramethyl-p-phenylenediamine dihydrochloride (TMPD)-ascorbate (with antimycin A) as substrates; and 2) at increasing adenosine diphosphate (ADP) concentration with glutamate-malate as substrate. As expected, maximal respiration decreased with O2 concentration and, when compared to glutamate-malate, the apparent Km O2 of mitochondria for O2 was significantly lower with TMPD-ascorbate with both waters. However, when compared to the water enriched in O2 by injection, the Km O2 was significantly lower with both electron donors in water enriched in O2 by electrolysis. This was not associated with any increase in the sensitivity of mitochondria to ADP; no significant difference was observed for the Km ADP between the two waters. In this experiment, a higher affinity of the mitochondria for O2 was observed in water enriched in O2 by electrolysis than by injection. This observation is consistent with the hypothesis that O2 diffusion can be facilitated in water enriched in O2 by the electrolytic process.

  1. Effect of combustion-chamber pressure and nozzle expansion ratio on theoretical performance of several rocket propellant systems

    NASA Technical Reports Server (NTRS)

    Morrell, Virginia E

    1956-01-01

    Theoretical calculations of specific impulse to determine the separate effects of increasing the combustion-chamber pressure and the nozzle expansion ratio on the performance of the propellants, hydrogen-fluorine, hydrogen-oxygen, ammonia-fluorine and AN-F-58 fuel - white fuming nitric acid (95 percent). The results indicate that an increase in specific impulse obtainable with an increase in combustion-chamber pressure is almost entirely caused by the increased expansion ratio through the nozzle.

  2. Medical Oxygen Safety

    MedlinePlus

    ... to the air a patient uses to breathe. Fire needs oxygen to burn. If a fire should start in an oxygen-enriched area, the ... Homes where medical oxygen is used need specific fire safety rules to keep people safe from fire ...

  3. Combustion characteristics and arsenic retention during co-combustion of agricultural biomass and bituminous coal.

    PubMed

    Zhou, Chuncai; Liu, Guijian; Wang, Xudong; Qi, Cuicui; Hu, Yunhu

    2016-08-01

    A combination of thermogravimetric analysis (TG) and laboratory-scale circulated fluidized bed combustion experiment was conducted to investigate the thermochemical, kinetic and arsenic retention behavior during co-combustion bituminous coal with typical agricultural biomass. Results shown that ignition performance and thermal reactivity of coal could be enhanced by adding biomass in suitable proportion. Arsenic was enriched in fly ash and associated with fine particles during combustion of coal/biomass blends. The emission of arsenic decreased with increasing proportion of biomass in blends. The retention of arsenic may be attributed to the interaction between arsenic and fly ash components. The positive correlation between calcium content and arsenic concentration in ash suggesting that the arsenic-calcium interaction may be regarded as the primary mechanism for arsenic retention. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Particle-bound reactive oxygen species (PB-ROS) emissions and formation pathways in residential wood smoke under different combustion and aging conditions

    NASA Astrophysics Data System (ADS)

    Zhou, Jun; Zotter, Peter; Bruns, Emily A.; Stefenelli, Giulia; Bhattu, Deepika; Brown, Samuel; Bertrand, Amelie; Marchand, Nicolas; Lamkaddam, Houssni; Slowik, Jay G.; Prévôt, André S. H.; Baltensperger, Urs; Nussbaumer, Thomas; El-Haddad, Imad; Dommen, Josef

    2018-05-01

    Wood combustion emissions can induce oxidative stress in the human respiratory tract by reactive oxygen species (ROS) in the aerosol particles, which are emitted either directly or formed through oxidation in the atmosphere. To improve our understanding of the particle-bound ROS (PB-ROS) generation potential of wood combustion emissions, a suite of smog chamber (SC) and potential aerosol mass (PAM) chamber experiments were conducted under well-determined conditions for different combustion devices and technologies, different fuel types, operation methods, combustion regimes, combustion phases, and aging conditions. The PB-ROS content and the chemical properties of the aerosols were quantified by a novel ROS analyzer using the DCFH (2',7'-dichlorofluorescin) assay and a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS). For all eight combustion devices tested, primary PB-ROS concentrations substantially increased upon aging. The level of primary and aged PB-ROS emission factors (EFROS) were dominated by the combustion device (within different combustion technologies) and to a greater extent by the combustion regimes: the variability within one device was much higher than the variability of EFROS from different devices. Aged EFROS under bad combustion conditions were ˜ 2-80 times higher than under optimum combustion conditions. EFROS from automatically operated combustion devices were on average 1 order of magnitude lower than those from manually operated devices, which indicates that automatic combustion devices operated at optimum conditions to achieve near-complete combustion should be employed to minimize PB-ROS emissions. The use of an electrostatic precipitator decreased the primary and aged ROS emissions by a factor of ˜ 1.5 which is however still within the burn-to-burn variability. The parameters controlling the PB-ROS formation in secondary organic aerosol were investigated by employing a regression model, including the fractions of

  5. A new test method for the assessment of the arc tracking properties of wire insulation in air, oxygen enriched atmospheres and vacuum

    NASA Technical Reports Server (NTRS)

    Koenig, Dieter

    1994-01-01

    Development of a new test method suitable for the assessment of the resistance of aerospace cables to arc tracking for different specific environmental and network conditions of spacecraft is given in view-graph format. The equipment can be easily adapted for tests at different realistic electrical network conditions incorporating circuit protection and the test system works equally well whatever the test atmosphere. Test results confirm that pure Kapton insulated wire has bad arcing characteristics and ETFE insulated wire is considerably better in air. For certain wires, arc tracking effects are increased at higher oxygen concentrations and significantly increased under vacuum. All tests on different cable insulation materials and in different environments, including enriched oxygen atmospheres, resulted in a more or less rapid extinguishing of all high temperature effects at the beginning of the post-test phase. In no case was a self-maintained fire initiated by the arc.

  6. Low NO[sub x], cogeneration process and system

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Bell, R.D.

    1993-07-06

    A process is described for low NO[sub x] cogeneration to produce electricity and useful heat, which comprises: providing fuel and oxygen to an internal combustion engine connected to drive an electric generator, to thereby generate electricity; recovering from said engine an exhaust stream including elevated NO[sub x] levels and combined oxygen; adding to said exhaust stream sufficient fuel to create a fuel-rich mixture, the quantity of fuel being sufficient to react with the available oxygen and reduce the NO[sub x], in said exhaust stream; providing said fuel-enriched exhaust stream to a thermal reactor and reacting therein said fuel, NO[sub x]more » and available oxygen, to provide a heated oxygen-depleted stream; cooling said oxygen-depleted stream by passing same through a first heat exchanger; adding conversion oxygen to said cooled stream from said heat exchanger, and passing the cooled oxygen-augmented stream over a first catalyst bed operated at a temperature of about 750 to 1,250 F under overall reducing conditions, the quantity of conversion oxygen added being in stoichiometric excess of the amount of NO[sub x], but less than the amount of combustibles; whereby the NO[sub x] is first oxidized to NO[sub 2], and then the NO[sub 2] is reduced by the excess combustibles; cooling said stream from said first catalyst bed to a temperature of about 450 to 650 F by passing said stream through a second heat exchanger; adding air to the resulting cooled stream to produce a further cooled stream at a temperature of about 400 to 600 F, and having a stoichiometric excess of oxygen; and passing said stream having said stoichiometric excess of oxygen over an oxidizing catalyst bed at said temperature of 400 to 600 F to oxidize remaining excess combustibles, to thereby provide an effluent stream having environmentally safe characteristics.« less

  7. Measured and Predicted Vapor Liquid Equilibrium of Ethanol-Gasoline Fuels with Insight on the Influence of Azeotrope Interactions on Aromatic Species Enrichment and Particulate Matter Formation in Spark Ignition Engines

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Ratcliff, Matthew A; McCormick, Robert L; Burke, Stephen

    A relationship has been observed between increasing ethanol content in gasoline and increased particulate matter (PM) emissions from direct injection spark ignition (DISI) vehicles. The fundamental cause of this observation is not well understood. One potential explanation is that increased evaporative cooling as a result of ethanol's high HOV may slow evaporation and prevent sufficient reactant mixing resulting in the combustion of localized fuel rich regions within the cylinder. In addition, it is well known that ethanol when blended in gasoline forms positive azeotropes which can alter the liquid/vapor composition during the vaporization process. In fact, it was shown recentlymore » through a numerical study that these interactions can retain the aromatic species within the liquid phase impeding the in-cylinder mixing of these compounds, which would accentuate PM formation upon combustion. To better understand the role of the azeotrope interactions on the vapor/liquid composition evolution of the fuel, distillations were performed using the Advanced Distillation Curve apparatus on carefully selected samples consisting of gasoline blended with ethanol and heavy aromatic and oxygenated compounds with varying vapor pressures, including cumene, p-cymene, 4-tertbutyl toluene, anisole, and 4-methyl anisole. Samples collected during the distillation indicate an enrichment of the heavy aromatic or oxygenated additive with an increase in initial ethanol concentration from E0 to E30. A recently developed distillation and droplet evaporation model is used to explore the influence of dilution effects versus azeotrope interactions on the aromatic species enrichment. The results suggest that HOV-cooling effects as well as aromatic species enrichment behaviors should be considered in future development of predictive indices to forecast the PM potential of fuels containing oxygenated compounds with comparatively high HOV.« less

  8. Focused RBCC Experiments: Two-Rocket Configuration Experiments and Hydrocarbon/Oxygen Rocket Ejector Experiments

    NASA Technical Reports Server (NTRS)

    Santoro, Robert J.; Pal, Sibtosh

    2003-01-01

    This addendum report documents the results of two additional efforts for the Rocket Based Combined Cycle (RBCC) rocket-ejector mode research work carried out at the Penn State Propulsion Engineering Research Center in support of NASA s technology development efforts for enabling 3 d generation Reusable Launch Vehicles (RLV). The tasks reported here build on an earlier NASA MSFC funded research program on rocket ejector investigations. The first task investigated the improvements of a gaseous hydrogen/oxygen twin thruster RBCC rocket ejector system over a single rocket system. The second task investigated the performance of a hydrocarbon (liquid JP-7)/gaseous oxygen single thruster rocket-ejector system. To gain a systematic understanding of the rocket-ejector s internal fluid mechanic/combustion phenomena, experiments were conducted with both direct-connect and sea-level static diffusion and afterburning (DAB) configurations for a range of rocket operating conditions. For all experimental conditions, overall system performance was obtained through global measurements of wall static pressure profiles, heat flux profiles and engine thrust. Detailed mixing and combustion information was obtained through Raman spectroscopy measurements of major species (gaseous oxygen, hydrogen, nitrogen and water vapor) for the gaseous hydrogen/oxygen rocket ejector experiments.

  9. Combustion flame-plasma hybrid reactor systems, and chemical reactant sources

    DOEpatents

    Kong, Peter C

    2013-11-26

    Combustion flame-plasma hybrid reactor systems, chemical reactant sources, and related methods are disclosed. In one embodiment, a combustion flame-plasma hybrid reactor system comprising a reaction chamber, a combustion torch positioned to direct a flame into the reaction chamber, and one or more reactant feed assemblies configured to electrically energize at least one electrically conductive solid reactant structure to form a plasma and feed each electrically conductive solid reactant structure into the plasma to form at least one product is disclosed. In an additional embodiment, a chemical reactant source for a combustion flame-plasma hybrid reactor comprising an elongated electrically conductive reactant structure consisting essentially of at least one chemical reactant is disclosed. In further embodiments, methods of forming a chemical reactant source and methods of chemically converting at least one reactant into at least one product are disclosed.

  10. Updating the conceptual model for fine particle mass emissions from combustion systems.

    PubMed

    Robinson, Allen L; Grieshop, Andrew P; Donahue, Neil M; Hunt, Sherri W

    2010-10-01

    Atmospheric transformations determine the contribution of emissions from combustion systems to fine particulate matter (PM) mass. For example, combustion systems emit vapors that condense onto existing particles or form new particles as the emissions are cooled and diluted. Upon entering the atmosphere, emissions are exposed to atmospheric oxidants and sunlight, which causes them to evolve chemically and physically, generating secondary PM. This review discusses these transformations, focusing on organic PM. Organic PM emissions are semi-volatile at atmospheric conditions and thus their partitioning varies continuously with changing temperature and concentration. Because organics contribute a large portion of the PM mass emitted by most combustion sources, these emissions cannot be represented using a traditional, static emission factor. Instead, knowledge of the volatility distribution of emissions is required to explicitly account for changes in gas-particle partitioning. This requires updating how PM emissions from combustion systems are measured and simulated from combustion systems. Secondary PM production often greatly exceeds the direct or primary PM emissions; therefore, secondary PM must be included in any assessment of the contribution of combustion systems to ambient PM concentrations. Low-volatility organic vapors emitted by combustion systems appear to be very important secondary PM precursors that are poorly accounted for in inventories and models. The review concludes by discussing the implications that the dynamic nature of these PM emissions have on source testing for emission inventory development and regulatory purposes. This discussion highlights important linkages between primary and secondary PM, which could lead to simplified certification test procedures while capturing the emission components that contribute most to atmospheric PM mass.

  11. Apparent Km of mitochondria for oxygen computed from Vmax measured in permeabilized muscle fibers is lower in water enriched in oxygen by electrolysis than injection

    PubMed Central

    Zoll, Joffrey; Bouitbir, Jamal; Sirvent, Pascal; Klein, Alexis; Charton, Antoine; Jimenez, Liliana; Péronnet, François R; Geny, Bernard; Richard, Ruddy

    2015-01-01

    Background It has been suggested that oxygen (O2) diffusion could be favored in water enriched in O2 by a new electrolytic process because of O2 trapping in water superstructures (clathrates), which could reduce the local pressure/content relationships for O2 and facilitate O2 diffusion along PO2 gradients. Materials and methods Mitochondrial respiration was compared in situ in saponin-skinned fibers isolated from the soleus muscles of Wistar rats, in solution enriched in O2 by injection or the electrolytic process 1) at an O2 concentration decreasing from 240 µmol/L to 10 µmol/L (132 mmHg to 5 mmHg), with glutamate–malate or N, N, N′, N′-tetramethyl-p-phenylenediamine dihydrochloride (TMPD)–ascorbate (with antimycin A) as substrates; and 2) at increasing adenosine diphosphate (ADP) concentration with glutamate–malate as substrate. Results As expected, maximal respiration decreased with O2 concentration and, when compared to glutamate–malate, the apparent Km O2 of mitochondria for O2 was significantly lower with TMPD–ascorbate with both waters. However, when compared to the water enriched in O2 by injection, the Km O2 was significantly lower with both electron donors in water enriched in O2 by electrolysis. This was not associated with any increase in the sensitivity of mitochondria to ADP; no significant difference was observed for the Km ADP between the two waters. Conclusion In this experiment, a higher affinity of the mitochondria for O2 was observed in water enriched in O2 by electrolysis than by injection. This observation is consistent with the hypothesis that O2 diffusion can be facilitated in water enriched in O2 by the electrolytic process. PMID:26203225

  12. An analysis of combustion studies in shock expansion tunnels and reflected shock tunnels

    NASA Technical Reports Server (NTRS)

    Jachimowski, Casimir J.

    1992-01-01

    The effect of initial nonequilibrium dissociated air constituents on the combustion of hydrogen in high-speed flows for a simulated Mach 17 flight condition was investigated by analyzing the results of comparative combustion experiments performed in a reflected shock tunnel test gas and in a shock expansion tunnel test gas. The results were analyzed and interpreted with a one-dimensional quasi-three-stream combustor code that includes finite rate combustion chemistry. The results of this study indicate that the combustion process is kinetically controlled in the experiments in both tunnels and the presence of the nonequilibrium partially dissociated oxygen in the reflected shock tunnel enhances the combustion. Methods of compensating for the effect of dissociated oxygen are discussed.

  13. Oxygen transport membrane system and method for transferring heat to catalytic/process reactors

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kelly, Sean M.; Kromer, Brian R.; Litwin, Michael M.

    A method and apparatus for producing heat used in a synthesis gas production process is provided. The disclosed method and apparatus include a plurality of tubular oxygen transport membrane elements adapted to separate oxygen from an oxygen containing stream contacting the retentate side of the membrane elements. The permeated oxygen is combusted with a hydrogen containing synthesis gas stream contacting the permeate side of the tubular oxygen transport membrane elements thereby generating a reaction product stream and radiant heat. The present method and apparatus also includes at least one catalytic reactor containing a catalyst to promote the steam reforming reactionmore » wherein the catalytic reactor is surrounded by the plurality of tubular oxygen transport membrane elements. The view factor between the catalytic reactor and the plurality of tubular oxygen transport membrane elements radiating heat to the catalytic reactor is greater than or equal to 0.5« less

  14. Oxygen transport membrane system and method for transferring heat to catalytic/process reactors

    DOEpatents

    Kelly, Sean M; Kromer, Brian R; Litwin, Michael M; Rosen, Lee J; Christie, Gervase Maxwell; Wilson, Jamie R; Kosowski, Lawrence W; Robinson, Charles

    2014-01-07

    A method and apparatus for producing heat used in a synthesis gas production is provided. The disclosed method and apparatus include a plurality of tubular oxygen transport membrane elements adapted to separate oxygen from an oxygen containing stream contacting the retentate side of the membrane elements. The permeated oxygen is combusted with a hydrogen containing synthesis gas stream contacting the permeate side of the tubular oxygen transport membrane elements thereby generating a reaction product stream and radiant heat. The present method and apparatus also includes at least one catalytic reactor containing a catalyst to promote the stream reforming reaction wherein the catalytic reactor is surrounded by the plurality of tubular oxygen transport membrane elements. The view factor between the catalytic reactor and the plurality of tubular oxygen transport membrane elements radiating heat to the catalytic reactor is greater than or equal to 0.5.

  15. U enrichment and Th/U fractionation in Archean boninites: Implications for paleo-ocean oxygenation and U cycling at juvenile subduction zones

    NASA Astrophysics Data System (ADS)

    Manikyamba, C.; Said, Nuru; Santosh, M.; Saha, Abhishek; Ganguly, Sohini; Subramanyam, K. S. V.

    2018-05-01

    Phanerozoic boninites record enrichments of U over Th, giving Th/U: 0.5-1.6, relative to intraoceanic island arc tholeiites (IAT) where Th/U averages 2.6. Uranium enrichment is attributed to incorporation of shallow, oxidized fluids, U-rich but Th-poor, from the slab into the melt column of boninites which form in near-trench to forearc settings of suprasubduction zone ophiolites. Well preserved Archean komatiite-tholeiite, plume-derived, oceanic volcanic sequences have primary magmatic Th/U ratios of 4.4-3.6, and Archean convergent margin IAT volcanic sequences, having REE and HFSE compositions similar to Phanerozoic IAT equivalents, preserve primary Th/U of 4-3.6. The best preserved Archean boninites of the 3.0 Ga Olondo and 2.7 Ga Gadwal greenstone belts, hosted in convergent margin ophiolite sequences, also show relative enrichments of U over Th, with low average Th/U ∼3 relative to coeval IAT, and Phanerozoic counterparts which are devoid of crustal contamination and therefore erupted in an intraoceanic setting, with minimal contemporaneous submarine hydrothermal alteration. Later enrichment of U is unlikely as Th-U-Nb-LREE patterns are coherent in these boninites whereas secondary effects induce dispersion of Th/U ratios. The variation in Th/U ratios from Archean to Phanerozoic boninites of greenstone belts to ophiolitic sequences reflect on genesis of boninitic lavas at different tectono-thermal regimes. Consequently, if the explanation for U enrichment in Phanerozoic boninites also applies to Archean examples, the implication is that U was soluble in oxygenated Archean marine water up to 600 Ma before the proposed great oxygenation event (GOE) at ∼2.4 Ga. This interpretation is consistent with large Ce anomalies in some hydrothermally altered Archean volcanic sequences aged 3.0-2.7 Ga.

  16. New potentials for conventional aircraft when powered by hydrogen-enriched gasoline

    NASA Technical Reports Server (NTRS)

    Menard, W. A.; Moynihan, P. I.; Rupe, J. H.

    1976-01-01

    Hydrogen enrichment for aircraft piston engines is under study in a new NASA program. The objective of the program is to determine the feasibility of inflight injection of hydrogen in general aviation aircraft engines to reduce fuel consumption and to lower emission levels. A catalytic hydrogen generator will be incorporated as part of the air induction system of a Lycoming turbocharged engine and will generate hydrogen by breaking down small amounts of the aviation gasoline used in the normal propulsion system. This hydrogen will then be mixed with gasoline and compressed air from the turbocharger before entering the engine combustion chamber. The special properties of the hydrogen-enriched gasoline allow the engine to operate at ultralean fuel/air ratios, resulting in higher efficiencies and hence less fuel consumption. This paper summarizes the results of a systems analysis study. Calculations assuming a Beech Duke aircraft indicate that fuel savings on the order of 20% are possible. An estimate of the potential for the utilization of hydrogen enrichment to control exhaust emissions indicates that it may be possible to meet the 1979 Federal emission standards.

  17. Determination of Local Experimental Heat-Transfer Coefficients on Combustion Side of an Ammonia-Oxygen Rocket

    NASA Technical Reports Server (NTRS)

    Liebert, Curt H.; Ehlers, Robert C.

    1961-01-01

    Local experimental heat-transfer coefficients were measured in the chamber and throat of a 2400-pound-thrust ammonia-oxygen rocket engine with a nominal chamber pressure of 600 pounds per square inch absolute. Three injector configurations were used. The rocket engine was run over a range of oxidant-fuel ratio and chamber pressure. The injector that achieved the best performance also produced the highest rates of heat flux at design conditions. The heat-transfer data from the best-performing injector agreed well with the simplified equation developed by Bartz at the throat region. A large spread of data was observed for the chamber. This spread was attributed generally to the variations of combustion processes. The spread was least evident, however, with the best-performing injector.

  18. Hot-Fire Test Results of Liquid Oxygen/RP-2 Multi-Element Oxidizer-Rich Preburners

    NASA Technical Reports Server (NTRS)

    Protz, C. S.; Garcia, C. P.; Casiano, M. J.; Parton, J. A.; Hulka, J. R.

    2016-01-01

    As part of the Combustion Stability Tool Development project funded by the Air Force Space and Missile Systems Center, the NASA Marshall Space Flight Center was contracted to assemble and hot-fire test a multi-element integrated test article demonstrating combustion characteristics of an oxygen/hydrocarbon propellant oxidizer-rich staged-combustion engine thrust chamber. Such a test article simulates flow through the main injectors of oxygen/kerosene oxidizer-rich staged combustion engines such as the Russian RD-180 or NK-33 engines, or future U.S.-built engine systems such as the Aerojet-Rocketdyne AR-1 engine or the Hydrocarbon Boost program demonstration engine. To supply the oxidizer-rich combustion products to the main injector of the integrated test article, existing subscale preburner injectors from a previous NASA-funded oxidizer-rich staged combustion engine development program were utilized. For the integrated test article, existing and newly designed and fabricated inter-connecting hot gas duct hardware were used to supply the oxidizer-rich combustion products to the oxidizer circuit of the main injector of the thrust chamber. However, before one of the preburners was used in the integrated test article, it was first hot-fire tested at length to prove it could provide the hot exhaust gas mean temperature, thermal uniformity and combustion stability necessary to perform in the integrated test article experiment. This paper presents results from hot-fire testing of several preburner injectors in a representative combustion chamber with a sonic throat. Hydraulic, combustion performance, exhaust gas thermal uniformity, and combustion stability data are presented. Results from combustion stability modeling of these test results are described in a companion paper at this JANNAF conference, while hot-fire test results of the preburner injector in the integrated test article are described in another companion paper.

  19. Evaluation and Improvement of Liquid Propellant Rocket Chugging Analysis Techniques. Part 2: a Study of Low Frequency Combustion Instability in Rocket Engine Preburners Using a Heterogeneous Stirred Tank Reactor Model. Final Report M.S. Thesis - Aug. 1987

    NASA Technical Reports Server (NTRS)

    Bartrand, Timothy A.

    1988-01-01

    During the shutdown of the space shuttle main engine, oxygen flow is shut off from the fuel preburner and helium is used to push the residual oxygen into the combustion chamber. During this process a low frequency combustion instability, or chug, occurs. This chug has resulted in damage to the engine's augmented spark igniter due to backflow of the contents of the preburner combustion chamber into the oxidizer feed system. To determine possible causes and fixes for the chug, the fuel preburner was modeled as a heterogeneous stirred tank combustion chamber, a variable mass flow rate oxidizer feed system, a constant mass flow rate fuel feed system and an exit turbine. Within the combustion chamber gases were assumed perfectly mixed. To account for liquid in the combustion chamber, a uniform droplet distribution was assumed to exist in the chamber, with mean droplet diameter determined from an empirical relation. A computer program was written to integrate the resulting differential equations. Because chamber contents were assumed perfectly mixed, the fuel preburner model erroneously predicted that combustion would not take place during shutdown. The combustion rate model was modified to assume that all liquid oxygen that vaporized instantaneously combusted with fuel. Using this combustion model, the effect of engine parameters on chamber pressure oscillations during the SSME shutdown was calculated.

  20. Combustion noise

    NASA Technical Reports Server (NTRS)

    Strahle, W. C.

    1977-01-01

    A review of the subject of combustion generated noise is presented. Combustion noise is an important noise source in industrial furnaces and process heaters, turbopropulsion and gas turbine systems, flaring operations, Diesel engines, and rocket engines. The state-of-the-art in combustion noise importance, understanding, prediction and scaling is presented for these systems. The fundamentals and available theories of combustion noise are given. Controversies in the field are discussed and recommendations for future research are made.

  1. Flow Friction or Spontaneous Ignition?

    NASA Technical Reports Server (NTRS)

    Stoltzfus, Joel M.; Gallus, Timothy D.; Sparks, Kyle

    2012-01-01

    "Flow friction," a proposed ignition mechanism in oxygen systems, has proved elusive in attempts at experimental verification. In this paper, the literature regarding flow friction is reviewed and the experimental verification attempts are briefly discussed. Another ignition mechanism, a form of spontaneous combustion, is proposed as an explanation for at least some of the fire events that have been attributed to flow friction in the literature. In addition, the results of a failure analysis performed at NASA Johnson Space Center White Sands Test Facility are presented, and the observations indicate that spontaneous combustion was the most likely cause of the fire in this 2000 psig (14 MPa) oxygen-enriched system.

  2. Thermal analysis and kinetics of coal during oxy-fuel combustion

    NASA Astrophysics Data System (ADS)

    Kosowska-Golachowska, Monika

    2017-08-01

    The pyrolysis and oxy-fuel combustion characteristics of Polish bituminous coal were studied using non-isothermal thermogravimetric analysis. Pyrolysis tests showed that the mass loss profiles were almost similar up to 870°C in both N2 and CO2 atmospheres, while further mass loss occurred in CO2 atmosphere at higher temperatures due to char-CO2 gasification. Replacement of N2 in the combustion environment by CO2 delayed the combustion of bituminous coal. At elevated oxygen levels, TG/DTG profiles shifted through lower temperature zone, ignition and burnout temperatures decreased and mass loss rate significantly increased and complete combustion was achieved at lower temperatures and shorter times. Kinetic analysis for the tested coal was performed using Kissinger-Akahira-Sunose (KAS) method. The activation energies of bituminous coal combustion at the similar oxygen content in oxy-fuel with that of air were higher than that in air atmosphere. The results indicated that, with O2 concentration increasing, the activation energies decreased.

  3. Combustion of liquid fuels in a flowing combustion gas environment at high pressures

    NASA Technical Reports Server (NTRS)

    Canada, G. S.; Faeth, G. M.

    1975-01-01

    The combustion of fuel droplets in gases which simulate combustion chamber conditions was considered both experimentally and theoretically. The fuel droplets were simulated by porous spheres and allowed to gasify in combustion gases produced by a burner. Tests were conducted for pressures of 1-40 atm, temperatures of 600-1500 K, oxygen concentrations of 0-13% (molar) and approach Reynolds numbers of 40-680. The fuels considered in the tests included methanol, ethanol, propanol-1, n-pentane, n-heptane and n-decane. Measurements were made of both the rate of gasification of the droplet and the liquid surface temperature. Measurements were compared with theory, involving various models of gas phase transport properties with a multiplicative correction for the effect of forced convection.

  4. Internet of Things Based Combustible Ice Safety Monitoring System Framework

    NASA Astrophysics Data System (ADS)

    Sun, Enji

    2017-05-01

    As the development of human society, more energy is requires to meet the need of human daily lives. New energies play a significant role in solving the problems of serious environmental pollution and resources exhaustion in the present world. Combustible ice is essentially frozen natural gas, which can literally be lit on fire bringing a whole new meaning to fire and ice with less pollutant. This paper analysed the advantages and risks on the uses of combustible ice. By compare to other kinds of alternative energies, the advantages of the uses of combustible ice were concluded. The combustible ice basic physical characters and safety risks were analysed. The developments troubles and key utilizations of combustible ice were predicted in the end. A real-time safety monitoring system framework based on the internet of things (IOT) was built to be applied in the future mining, which provide a brand new way to monitoring the combustible ice mining safety.

  5. Apparatus and method for gas turbine active combustion control system

    NASA Technical Reports Server (NTRS)

    Knobloch, Aaron (Inventor); Mancini, Alfred Albert (Inventor); Myers, William J. (Inventor); Fortin, Jeffrey B. (Inventor); Umeh, Chukwueloka (Inventor); Kammer, Leonardo C. (Inventor); Shah, Minesh (Inventor)

    2011-01-01

    An Active Combustion Control System and method provides for monitoring combustor pressure and modulating fuel to a gas turbine combustor to prevent combustion dynamics and/or flame extinguishments. The system includes an actuator, wherein the actuator periodically injects pulsed fuel into the combustor. The apparatus also includes a sensor connected to the combustion chamber down stream from an inlet, where the sensor generates a signal detecting the pressure oscillations in the combustor. The apparatus controls the actuator in response to the sensor. The apparatus prompts the actuator to periodically inject pulsed fuel into the combustor at a predetermined sympathetic frequency and magnitude, thereby controlling the amplitude of the pressure oscillations in the combustor by modulating the natural oscillations.

  6. Promoted Metals Combustion at Ambient and Elevated Temperatures

    NASA Technical Reports Server (NTRS)

    Engel, Carl D.; Herald, Stephen D.; Davis, S. Eddie

    2005-01-01

    Promoted combustion testing of materials, Test 17 of NASA STD-6001, has been used to assess metal propensity to burn in oxygen rich environments. An igniter is used at the bottom end of a rod to promote ignition, and if combustion is sustained, the burning progresses from the bottom to the top of the rod. The physical mechanisms are very similar to the upward flammability test, Test 1 of NASA STD-6001. The differences are in the normal environmental range of pressures, oxygen content, and sample geometry. Upward flammability testing of organic materials can exhibit a significant transitional region between no burning to complete quasi-state burning. In this transitional region, the burn process exhibits a probabilistic nature. This transitional region has been identified for metals using the promoted combustion testing method at ambient initial temperatures. The work given here is focused on examining the transitional region and the quasi-steady burning region both at conventional ambient testing conditions and at elevated temperatures. A new heated promoted combustion facility and equipment at Marshall Space Flight Center have just been completed to provide the basic data regarding the metals operating temperature limits in contact with oxygen rich atmospheres at high pressures. Initial data have been obtained for Stainless Steel 304L, Stainless Steel 321, Haynes 214, and Inconel 718 at elevated temperatures in 100-percent oxygen atmospheres. These data along with an extended data set at ambient initial temperature test conditions are examined. The pressure boundaries of acceptable, non-burning usage is found to be lowered at elevated temperature.

  7. Update for combustion properties of wood components

    Treesearch

    Mark Dietenberger

    2002-01-01

    The combustion properties of various biomass and wood materials from various references and from our laboratory were reanalysed. The net heat of combustion for cellulosic materials was found to be 13.23 kJ/g times the ratio of stoichiometric oxygen mass to fuel mass, r[subscript]o, regardless of the material composition. Bomb calorimeter data for original, charred and...

  8. Device to lower NOx in a gas turbine engine combustion system

    DOEpatents

    Laster, Walter R; Schilp, Reinhard; Wiebe, David J

    2015-02-24

    An emissions control system for a gas turbine engine including a flow-directing structure (24) that delivers combustion gases (22) from a burner (32) to a turbine. The emissions control system includes: a conduit (48) configured to establish fluid communication between compressed air (22) and the combustion gases within the flow-directing structure (24). The compressed air (22) is disposed at a location upstream of a combustor head-end and exhibits an intermediate static pressure less than a static pressure of the combustion gases within the combustor (14). During operation of the gas turbine engine a pressure difference between the intermediate static pressure and a static pressure of the combustion gases within the flow-directing structure (24) is effective to generate a fluid flow through the conduit (48).

  9. Metal-air flow batteries using oxygen enriched electrolyte

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Zheng, Jian-ping; Andrei, Petru; Shellikeri, Annadanesh

    A metal air flow battery includes an electrochemical reaction unit and an oxygen exchange unit. The electrochemical reaction unit includes an anode electrode, a cathode electrode, and an ionic conductive membrane between the anode and the cathode, an anode electrolyte, and a cathode electrolyte. The oxygen exchange unit contacts the cathode electrolyte with oxygen separate from the electrochemical reaction unit. At least one pump is provided for pumping cathode electrolyte between the electrochemical reaction unit and the oxygen exchange unit. A method for producing an electrical current is also disclosed.

  10. Metal-air flow batteries using oxygen enriched electrolyte

    DOEpatents

    Zheng, Jian-ping; Andrei, Petru; Shellikeri, Annadanesh; Chen, Xujie

    2017-08-01

    A metal air flow battery includes an electrochemical reaction unit and an oxygen exchange unit. The electrochemical reaction unit includes an anode electrode, a cathode electrode, and an ionic conductive membrane between the anode and the cathode, an anode electrolyte, and a cathode electrolyte. The oxygen exchange unit contacts the cathode electrolyte with oxygen separate from the electrochemical reaction unit. At least one pump is provided for pumping cathode electrolyte between the electrochemical reaction unit and the oxygen exchange unit. A method for producing an electrical current is also disclosed.

  11. FY2017 Advanced Combustion Systems and Fuels Annual Progress Report

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    None, None

    The Advanced Combustion Systems and Fuels Program supports VTO’s goal and focuses early-stage research and development (R&D) to improve understanding of the combustion processes, fuel properties, and emission control technologies while generating knowledge and insight necessary for industry to develop the next generation of engines.

  12. Combustion characteristics of paper and sewage sludge in a pilot-scale fluidized bed.

    PubMed

    Yu, Yong-Ho; Chung, Jinwook

    2015-01-01

    This study characterizes the combustion of paper and sewage sludge in a pilot-scale fluidized bed. The highest temperature during combustion within the system was found at the surface of the fluidized bed. Paper sludge containing roughly 59.8% water was burned without auxiliary fuel, but auxiliary fuel was required to incinerate the sewage sludge, which contained about 79.3% water. The stability of operation was monitored based on the average pressure and the standard deviation of pressure fluctuations. The average pressure at the surface of the fluidized bed decreased as the sludge feed rate increased. However, the standard deviation of pressure fluctuations increased as the sludge feed rate increased. Finally, carbon monoxide (CO) emissions decreased as oxygen content increased in the flue gas, and nitrogen oxide (NOx) emissions were also tied with oxygen content.

  13. Characterization of Oxy-combustion Impacts in Existing Coal-fired Boilers

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Adams, Bradley; Davis, Kevin; Senior, Constance

    Reaction Engineering International (REI) managed a team of experts from University of Utah, Siemens Energy, Praxair, Vattenfall AB, Sandia National Laboratories, Brigham Young University (BYU) and Corrosion Management Ltd. to perform multi-scale experiments, coupled with mechanism development, process modeling and CFD modeling, for both applied and fundamental investigations. The primary objective of this program was to acquire data and develop tools to characterize and predict impacts of CO{sub 2} flue gas recycle and burner feed design on flame characteristics (burnout, NO{sub x}, SO{sub x}, mercury and fine particle emissions, heat transfer) and operational concerns (fouling, slagging and corrosion) inherent inmore » the retrofit of existing coal-fired boilers for oxy-coal combustion. Experimental work was conducted at Sandia National Laboratories’ Entrained Flow Reactor, the University of Utah Industrial Combustion Research Facility, and Brigham Young University. Process modeling and computational fluid dynamics (CFD) modeling was performed at REI. Successful completion of the project objectives resulted in the following key deliverables: 1) Multi-scale test data from 0.1 kW bench-scale, 100 kW and 200 kW laboratory-scale, and 1 MW semi-industrial scale combustors that describe differences in flame characteristics, fouling, slagging and corrosion for coal combustion under air-firing and oxygen-firing conditions, including sensitivity to oxy-burner design and flue gas recycle composition. 2) Validated mechanisms developed from test data that describe fouling, slagging, waterwall corrosion, heat transfer, char burnout and sooting under coal oxy-combustion conditions. The mechanisms were presented in a form suitable for inclusion in CFD models or process models. 3) Principles to guide design of pilot-scale and full-scale coal oxy-firing systems and flue gas recycle configurations, such that boiler operational impacts from oxy-combustion retrofits are minimized

  14. Droplet Combustion Experiment movie

    NASA Technical Reports Server (NTRS)

    2003-01-01

    The Droplet Combustion Experiment (DCE) was designed to investigate the fundamental combustion aspects of single, isolated droplets under different pressures and ambient oxygen concentrations for a range of droplet sizes varying between 2 and 5 mm. The DCE principal investigator was Forman Williams, University of California, San Diego. The experiment was part of the space research investigations conducted during the Microgravity Science Laboratory-1 mission (STS-83, April 4-8 1997; the shortened mission was reflown as MSL-1R on STS-94). Advanced combustion experiments will be a part of investigations plarned for the International Space Station. (1.1 MB, 12-second MPEG, screen 320 x 240 pixels; downlinked video, higher quality not available)A still JPG composite of this movie is available at http://mix.msfc.nasa.gov/ABSTRACTS/MSFC-0300164.html.

  15. Transient combustion in hybrid rockets

    NASA Astrophysics Data System (ADS)

    Karabeyoglu, Mustafa Arif

    1998-09-01

    Hybrid rockets regained interest recently as an alternative chemical propulsion system due to their advantages over the solid and liquid systems that are currently in use. Development efforts on hybrids revealed two important problem areas: (1) low frequency instabilities and (2) slow transient response. Both of these are closely related to the transient behavior which is a poorly understood aspect of hybrid operation. This thesis is mainly involved with a theoretical study of transient combustion in hybrid rockets. We follow the methodology of identifying and modeling the subsystems of the motor such as the thermal lags in the solid, boundary layer combustion and chamber gasdynamics from a dynamic point of view. We begin with the thermal lag in the solid which yield the regression rate for any given wall heat flux variation. Interesting phenomena such as overshooting during throttling and the amplification and phase lead regions in the frequency domain are discovered. Later we develop a quasi-steady transient hybrid combustion model supported with time delays for the boundary layer processes. This is integrated with the thermal lag system to obtain the thermal combustion (TC) coupled response. The TC coupled system with positive delays generated low frequency instabilities. The scaling of the instabilities are in good agreement with actual motor test data. Finally, we formulate a gasdynamic model for the hybrid chamber which successfully resolves the filling/emptying and longitudinal acoustic behavior of the motor. The TC coupled system is later integrated to the gasdynamic model to obtain the overall response (TCG coupled system) of gaseous oxidizer motors with stiff feed systems. Low frequency instabilities were also encountered for the TCG coupled system. Apart from the transient investigations, the regression rate behavior of liquefying hybrid propellants such as solid cryogenic materials are also studied. The theory is based on the possibility of enhancement

  16. Improve Your Boiler's Combustion Efficiency: Office of Industrial Technologies (OIT) Steam Energy Tips No.4

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Not Available

    2002-03-01

    Operating your boiler with an optimum amount of excess air will minimize heat loss up the stack and improve combustion efficiency. Combustion efficiency is a measure of how effectively the heat content of a fuel is transferred into usable heat. The stack temperature and flue gas oxygen (or carbon dioxide) concentrations are primary indicators of combustion efficiency. Given complete mixing, a precise or stoichiometric amount of air is required to completely react with a given quantity of fuel. In practice, combustion conditions are never ideal, and additional or ''excess'' air must be supplied to completely burn the fuel. The correctmore » amount of excess air is determined from analyzing flue gas oxygen or carbon dioxide concentrations. Inadequate excess air results in unburned combustibles (fuel, soot, smoke, and carbon monoxide) while too much results in heat lost due to the increased flue gas flow--thus lowering the overall boiler fuel-to-steam efficiency. The table relates stack readings to boiler performance. On well-designed natural gas-fired systems, an excess air level of 10% is attainable. An often stated rule of thumb is that boiler efficiency can be increased by 1% for each 15% reduction in excess air or 40 F reduction in stack gas temperature.« less

  17. Catalytic Effect of Pd Clusters in the Poly( N-vinyl-2-pyrrolidone) Combustion

    NASA Astrophysics Data System (ADS)

    Schiavo, L.; De Nicola, S.; Carotenuto, G.

    2018-01-01

    Pd(0) is able to catalyze oxygen-involving reactions because of its capability to convert molecular oxygen to the very reactive atomic form. Consequently, the embedding of a little amount of Pd(0) clusters in polymeric phases can be technologically exploited to enhance the incineration kinetic of these polymers. The effect of nanostructuration on the Pd(0) catalytic activity in the polymer incineration reaction has been studied using poly( N-vinyl-2-pyrrolidone) ( \\overline{Mw} = 10,000 gmol-1) as polymeric model system. A change in the PVP incineration kinetic mechanism with significant increase in the reaction rate was experimentally found. The kinetic of the Pd(0)-catalyzed combustion has been studied by isothermal thermogravimetric analysis. After a short induction time, the combustion in presence of Pd(0) clusters shifted to a zero-order kinetic from a second-order kinetic control, which is operative in pure PVP combustion reaction. In addition, the activation energy resulted much lowered compared to the pure PVP incineration case (from 300 to 260 kJ/mol).

  18. Liquid Methane/Oxygen Injector Study for Mars Ascent Engines

    NASA Technical Reports Server (NTRS)

    Trinh, Huu Phuoc

    1999-01-01

    As a part of the advancing technology of the cryogenic propulsion system for the Mars exploration mission, this effort aims at evaluating propellant injection concepts for liquid methane/liquid oxygen (LOX) rocket engines. Split-triplet and unlike impinging injectors were selected for this study. A total of four injector configurations were tested under combustion conditions in a modular combustor test article (MCTA), equipped with optically accessible windows, at MSFC. A series of forty hot-fire tests, which covered a wide range of engine operating conditions with the chamber pressure ranging from 320 to 510 and the mixture ratio from 1.5 to 3.5, were conducted. The test matrix also included a variation in the combustion chamber length for the purpose of investigating its effects on the combustion performance and stability. Initial assessments of the test results showed that the injectors provided stable combustion and there were no injector face overheating problems under all operating conditions. The Raman scattering signal measurement method was successfully demonstrated for the hydrocarbon/oxygen reactive flow field. The near-injector face flow field was visually observed through the use of an infrared camera. Chamber wall temperature, high frequency chamber pressure, and average throat section heat flux were also recorded throughout the test series. Assessments of the injector performance are underway.

  19. Development of Novel Fe-Based Coating Systems for Internal Combustion Engines

    NASA Astrophysics Data System (ADS)

    Bobzin, K.; Öte, M.; Königstein, T.; Dröder, K.; Hoffmeister, H.-W.; Mahlfeld, G.; Schläfer, T.

    2018-04-01

    Nowadays, combustion engines are the most common way to power vehicles. Thereby, losses occur due to cooling, exhaust gas and friction. With regard to frictional losses, highest potentials for optimization can be found in the tribological system of the inner surface of combustion chamber and piston ring. Besides friction, corrosive stress increases, e.g., due to utilization of exhaust gas recovery. In order to save energy, reduce emissions and enhance the life span of combustion engines, the demand for innovative coating material systems, especially for the inner surface of combustion chamber, increases. This study focuses on the development of innovative iron-based coating materials for the combustion chamber. As a first step, the plasma transferred wire arc and rotating single wire arc (RSW) technologies were compared using 0.8% C-steel as a reference. Subsequently, RSW was used for coating deposition using an innovative iron-based feedstock material. In order to improve wear and corrosion resistance, boron and chromium were added to the feedstock material. After deposition, different honing topographies were manufactured and compared under tribological load. Furthermore, electrochemical corrosion tests were conducted using an electrolyte simulating the exhaust gas concentrate. Especially with regard to corrosion, the novel coating system FeCrBMn showed promising results.

  20. Thermochemical conversion of biomass in smouldering combustion across scales: The roles of heterogeneous kinetics, oxygen and transport phenomena.

    PubMed

    Huang, Xinyan; Rein, Guillermo

    2016-05-01

    The thermochemical conversion of biomass in smouldering combustion is investigated here by combining experiments and modeling at two scales: matter (1mg) and bench (100g) scales. Emphasis is put on the effect of oxygen (0-33vol.%) and oxidation reactions because these are poorly studied in the literature in comparison to pyrolysis. The results are obtained for peat as a representative biomass for which there is high-quality experimental data published previously. Three kinetic schemes are explored, including various steps of drying, pyrolysis and oxidation. The kinetic parameters are found using the Kissinger-Genetic Algorithm method, and then implemented in a one-dimensional model of heat and mass transfer. The predictions are validated with thermogravimetric and bench-scale experiments and then analyzed to unravel the role of heterogeneous reaction. This is the first time that the influence of oxygen on biomass smouldering is explained in terms of both chemistry and transport phenomena across scales. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  1. 76 FR 12550 - Lavatory Oxygen Systems

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-08

    ... Lavatory Oxygen Systems AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Interim final rule... related to the provisioning of supplemental oxygen inside lavatories. This action is necessitated by other mandatory actions that temporarily render such oxygen systems inoperative. DATES: This interim rule is...

  2. Modeling of Plasma Assisted Combustion

    NASA Astrophysics Data System (ADS)

    Akashi, Haruaki

    2012-10-01

    Recently, many experimental study of plasma-assisted combustion has been done. However, numerous complex reactions in combustion of hydrocarbons are preventing from theoritical study for clarifying inside the plasma-assisted combustion, and the effect of plasma-assist is still not understood. Shinohara and Sasaki [1,2] have reported that the shortening of flame length by irradiating microwave without increase of gas temperature. And they also reported that the same phenomena would occur when applying dielectric barrier discharges to the flame using simple hydrocarbon, methane. It is suggested that these phenomena may result by the electron heating. To clarify this phenomena, electron behavior under microwave and DBD was examined. For the first step of DBD plasma-assisted combustion simulation, electron Monte Carlo simulation in methane, oxygen and argon mixture gas(0.05:0.14:0.81) [2] has been done. Electron swarm parameters are sampled and electron energy distribution function (EEDF)s are also determined. In the combustion, gas temperature is higher(>1700K), so reduced electric field E/N becomes relatively high(>10V/cm/Torr). The electrons are accelerated to around 14 eV. This result agree with the optical emission from argon obtained by the experiment of reference [2]. Dissociation frequency of methane and oxygens are obtained in high. This might be one of the effect of plasma-assist. And it is suggested that the electrons should be high enough to dissociate methane, but plasma is not needed.[4pt] [1] K. Shinohara et al, J. Phys. D:Appl. Phys., 42, 182008 (1-7) (2009).[0pt] [2] K. Sasaki, 64th Annual Gaseous Electronic Conference, 56, 15 CT3.00001(2011).

  3. Functioning of a Shallow-Water Sediment System during Experimental Warming and Nutrient Enrichment

    PubMed Central

    Alsterberg, Christian; Sundbäck, Kristina; Hulth, Stefan

    2012-01-01

    Effects of warming and nutrient enrichment on intact unvegetated shallow-water sediment were investigated for 5 weeks in the autumn under simulated natural field conditions, with a main focus on trophic state and benthic nitrogen cycling. In a flow-through system, sediment was exposed to either seawater at ambient temperature or seawater heated 4°C above ambient, with either natural or nutrient enriched water. Sediment–water fluxes of oxygen and inorganic nutrients, nitrogen mineralization, and denitrification were measured. Warming resulted in an earlier shift to net heterotrophy due to increased community respiration; primary production was not affected by temperature but (slightly) by nutrient enrichment. The heterotrophic state was, however, not further strengthened by warming, but was rather weakened, probably because increased mineralization induced a shortage of labile organic matter. Climate-related warming of seawater during autumn could therefore, in contrast to previous predictions, induce shorter but more intensive heterotrophic periods in shallow-water sediments, followed by longer autotrophic periods. Increased nitrogen mineralization and subsequent effluxes of ammonium during warming suggested a preferential response of organisms driving nitrogen mineralization when compared to sinks of ammonium such as nitrification and algal assimilation. Warming and nutrient enrichment resulted in non-additive effects on nitrogen mineralization and denitrification (synergism), as well as on benthic fluxes of phosphate (antagonism). The mode of interaction appears to be related to the trophic level of the organisms that are the main drivers of the affected processes. Despite the weak response of benthic microalgae to both warming and nutrient enrichment, the assimilation of nitrogen by microalgae was similar in magnitude to rates of nitrogen mineralization. This implies a sustained filter function and retention capacity of nutrients by the sediment. PMID

  4. [Study on expert system of infrared spectral characteristic of combustible smoke agent].

    PubMed

    Song, Dong-ming; Guan, Hua; Hou, Wei; Pan, Gong-pei

    2009-05-01

    The present paper studied the application of expert system in prediction of infrared spectral characteristic of combustible anti-infrared smoke agent. The construction of the expert system was founded, based on the theory of minimum free energy and infrared spectral addition. After the direction of smoke agent was input, the expert system could figure out the final combustion products. Then infrared spectrogram of smoke could also be simulated by adding the spectra of all of the combustion products. Meanwhile, the screening index of smoke was provided in the wave bands of 3-5 im and 8-14 microm. FTIR spectroscope was used to investigate the performance of one kind of HC smoke. The combustion products calculated by the expert system were coincident with the actual data, and the simulant infrared spectrum was also similar to the real one of the smoke. The screening index given by the system was consistent with the known facts. It was showed that a new approach was offered for the fast discrimination of varieties of directions of smoke agent.

  5. 14 CFR 23.1445 - Oxygen distribution system.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Oxygen distribution system. 23.1445 Section... Equipment § 23.1445 Oxygen distribution system. (a) Except for flexible lines from oxygen outlets to the... used for any oxygen line that is normally pressurized during flight. (b) Nonmetallic oxygen...

  6. 14 CFR 23.1445 - Oxygen distribution system.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Oxygen distribution system. 23.1445 Section... Equipment § 23.1445 Oxygen distribution system. (a) Except for flexible lines from oxygen outlets to the... used for any oxygen line that is normally pressurized during flight. (b) Nonmetallic oxygen...

  7. 14 CFR 23.1445 - Oxygen distribution system.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Oxygen distribution system. 23.1445 Section... Equipment § 23.1445 Oxygen distribution system. (a) Except for flexible lines from oxygen outlets to the... used for any oxygen line that is normally pressurized during flight. (b) Nonmetallic oxygen...

  8. 14 CFR 23.1445 - Oxygen distribution system.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Oxygen distribution system. 23.1445 Section... Equipment § 23.1445 Oxygen distribution system. (a) Except for flexible lines from oxygen outlets to the... used for any oxygen line that is normally pressurized during flight. (b) Nonmetallic oxygen...

  9. Solid fuel combustion system for gas turbine engine

    DOEpatents

    Wilkes, Colin; Mongia, Hukam C.

    1993-01-01

    A solid fuel, pressurized fluidized bed combustion system for a gas turbine engine includes a carbonizer outside of the engine for gasifying coal to a low Btu fuel gas in a first fraction of compressor discharge, a pressurized fluidized bed outside of the engine for combusting the char residue from the carbonizer in a second fraction of compressor discharge to produce low temperature vitiated air, and a fuel-rich, fuel-lean staged topping combustor inside the engine in a compressed air plenum thereof. Diversion of less than 100% of compressor discharge outside the engine minimizes the expense of fabricating and maintaining conduits for transferring high pressure and high temperature gas and incorporation of the topping combustor in the compressed air plenum of the engine minimizes the expense of modifying otherwise conventional gas turbine engines for solid fuel, pressurized fluidized bed combustion.

  10. Oxygen concentration sensor for an internal combustion engine

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Nakajima, T.; Okada, Y.; Mieno, T.

    1988-09-29

    This patent describes an oxygen concentration sensor, comprising: an oxygen ion conductive solid electrolyte member forming a gas diffusion restricted region into which a measuring gas is introduced; a pair of electrodes sandwiching the solid electrolyte member; pump current supply means applying a pump voltage to the pair of electrodes through a current detection element to generate a pump current; and a heater element connected to the solid electrolyte member for heating the solid electrolyte member for heating the solid electrolyte member when a heater current is supplied from a heater current source; wherein the oxygen concentration sensor detects anmore » oxygen concentration in the measuring gas in terms of a current value of the pump current supplied through the current detection element and controls oxygen concentration in the gas diffusion restricted region by conducting oxygen ions through the solid electrolyte member in accordance to the flow of the pump current; and wherein the current detection element is connected to the electrode of the pair of electrodes facing the gas diffusion restricted region for insuring that the current value is representative of the pump current and possible leakage current from the heater current.« less

  11. Real gas CFD simulations of hydrogen/oxygen supercritical combustion

    NASA Astrophysics Data System (ADS)

    Pohl, S.; Jarczyk, M.; Pfitzner, M.; Rogg, B.

    2013-03-01

    A comprehensive numerical framework has been established to simulate reacting flows under conditions typically encountered in rocket combustion chambers. The model implemented into the commercial CFD Code ANSYS CFX includes appropriate real gas relations based on the volume-corrected Peng-Robinson (PR) equation of state (EOS) for the flow field and a real gas extension of the laminar flamelet combustion model. The results indicate that the real gas relations have a considerably larger impact on the flow field than on the detailed flame structure. Generally, a realistic flame shape could be achieved for the real gas approach compared to experimental data from the Mascotte test rig V03 operated at ONERA when the differential diffusion processes were only considered within the flame zone.

  12. Mercury Adsorption and Oxidation over Cobalt Oxide Loaded Magnetospheres Catalyst from Fly Ash in Oxyfuel Combustion Flue Gas.

    PubMed

    Yang, Jianping; Zhao, Yongchun; Chang, Lin; Zhang, Junying; Zheng, Chuguang

    2015-07-07

    Cobalt oxide loaded magnetospheres catalyst from fly ash (Co-MF catalyst) showed good mercury removal capacity and recyclability under air combustion flue gas in our previous study. In this work, the Hg(0) removal behaviors as well as the involved reactions mechanism were investigated in oxyfuel combustion conditions. Further, the recyclability of Co-MF catalyst in oxyfuel combustion atmosphere was also evaluated. The results showed that the Hg(0) removal efficiency in oxyfuel combustion conditions was relative high compared to that in air combustion conditions. The presence of enriched CO2 (70%) in oxyfuel combustion atmosphere assisted the mercury oxidation due to the oxidation of function group of C-O formed from CO2. Under both atmospheres, the mercury removal efficiency decreased with the addition of SO2, NO, and H2O. However, the enriched CO2 in oxyfuel combustion atmosphere could somewhat weaken the inhibition of SO2, NO, and H2O. The multiple capture-regeneration cycles demonstrated that the Co-MF catalyst also present good regeneration performance in oxyfuel combustion atmosphere.

  13. Oxygen- and Nitrogen-Enriched 3D Porous Carbon for Supercapacitors of High Volumetric Capacity.

    PubMed

    Li, Jia; Liu, Kang; Gao, Xiang; Yao, Bin; Huo, Kaifu; Cheng, Yongliang; Cheng, Xiaofeng; Chen, Dongchang; Wang, Bo; Sun, Wanmei; Ding, Dong; Liu, Meilin; Huang, Liang

    2015-11-11

    Efficient utilization and broader commercialization of alternative energies (e.g., solar, wind, and geothermal) hinges on the performance and cost of energy storage and conversion systems. For now and in the foreseeable future, the combination of rechargeable batteries and electrochemical capacitors remains the most promising option for many energy storage applications. Porous carbonaceous materials have been widely used as an electrode for batteries and supercapacitors. To date, however, the highest specific capacitance of an electrochemical double layer capacitor is only ∼200 F/g, although a wide variety of synthetic approaches have been explored in creating optimized porous structures. Here, we report our findings in the synthesis of porous carbon through a simple, one-step process: direct carbonization of kelp in an NH3 atmosphere at 700 °C. The resulting oxygen- and nitrogen-enriched carbon has a three-dimensional structure with specific surface area greater than 1000 m(2)/g. When evaluated as an electrode for electrochemical double layer capacitors, the porous carbon structure demonstrated excellent volumetric capacitance (>360 F/cm(3)) with excellent cycling stability. This simple approach to low-cost carbonaceous materials with unique architecture and functionality could be a promising alternative to fabrication of porous carbon structures for many practical applications, including batteries and fuel cells.

  14. PROPULSE 980: A Hydrogen Peroxide Enrichment System

    NASA Technical Reports Server (NTRS)

    Boxwell, Robert; Bromley, G.; Wanger, Robert; Pauls, Dan; Maynard, Bryon; McNeal, Curtis; Dumbacher, D. L. (Technical Monitor)

    2000-01-01

    The PROPULSE 980 unit is a transportable processing plant that enriches aerospace grade hydrogen peroxide from 90% to 98% final concentration. The unit was developed by Degussa-H Is, in cooperation with Orbital, NASA Marshall Space Center, and NASA Stennis Space Center. The system is a self-contained unit that houses all of the process equipment, instrumentation and controls to perform the concentration operation nearly autonomously. It is designed to produce non-bulk quantities of 98% hydrogen peroxide. The enrichment unit design also maintains system, personnel and environmental safety during all aspects of the enrichment process and final product storage. As part of the Propulse 980 checkout and final buyoff, it will be disassembled at the Degussa-H Is Corporation plant in Theodore, AL, transported to the Stennis Space Center, reassembled and subjected to a series of checkout tests to verify design objectives have been met. This paper will summarize the basic project elements and provide an update on the present status of the project.

  15. Heater for Combustible-Gas Tanks

    NASA Technical Reports Server (NTRS)

    Ingle, Walter B.

    1987-01-01

    Proposed heater for pressurizing hydrogen, oxygen, or another combustible liquid or gas sealed in immersion cup in pressurized tank. Firmly supported in finned cup, coiled rod transfers heat through liquid metal to gas tank. Heater assembly welded or bolted to tank flange.

  16. SITE TECHNOLOGY CAPSULE: SONOTECH PULSE COMBUSTION SYSTEM

    EPA Science Inventory

    Sonotech has targeted waste incineration as a potential application for this technology. Based on bench-scale rotary-kiln simulator tests, Sonotech proposed a demonstration under the SITE program to evaluate the Sonotech pulse combustion system on a larger scale at EPA's IRF in J...

  17. Tripropellant combustion process

    NASA Technical Reports Server (NTRS)

    Kmiec, T. D.; Carroll, R. G.

    1988-01-01

    The addition of small amounts of hydrogen to the combustion of LOX/hydrocarbon propellants in large rocket booster engines has the potential to enhance the system stability. Programs being conducted to evaluate the effects of hydrogen on the combustion of LOX/hydrocarbon propellants at supercritical pressures are described. Combustion instability has been a problem during the development of large hydrocarbon fueled rocket engines. At the higher combustion chamber pressures expected for the next generation of booster engines, the effect of unstable combustion could be even more destructive. The tripropellant engine cycle takes advantage of the superior cooling characteristics of hydrogen to cool the combustion chamber and a small amount of the hydrogen coolant can be used in the combustion process to enhance the system stability. Three aspects of work that will be accomplished to evaluate tripropellant combustion are described. The first is laboratory demonstration of the benefits through the evaluation of drop size, ignition delay and burning rate. The second is analytical modeling of the combustion process using the empirical relationship determined in the laboratory. The third is a subscale demonstration in which the system stability will be evaluated. The approach for each aspect is described and the analytical models that will be used are presented.

  18. Fuels and Combustion | Transportation Research | NREL

    Science.gov Websites

    determining if and at what levels biomass-derived oxygenates may be commercially feasible in drop-in fuels experiments examine combustion across a wide range of temperatures, pressures, and levels of dilution, and

  19. Preliminary tests of an advanced high-temperature combustion system

    NASA Technical Reports Server (NTRS)

    Wear, J. D.; Trout, A. M.; Smith, J. M.; Jacobs, R. E.

    1983-01-01

    A combustion system has been developed to operate efficiently and with good durability at inlet pressures to 4.05 MPa (40 atm), inlet air temperatures to 900 K, and exhaust gas temperatures to 2480 K. A preliminary investigation of this system was conducted at inlet pressures to 0.94 MPa (9 atm), a nominal inlet air temperature of 560 K, and exhaust gas temperatures to 2135 K. A maximum combustion efficiency of 98.5 percent was attained at a fuel-air ratio of 0.033; the combustion efficiency decreased to about 90 percent as the fuel-air ratio was increased to 0.058. An average liner metal temperature of 915 K, 355 kelvins greater than the nominal inlet air temperature, was reached with an average exhaust gas temperature of 2090 K. The maximum local metal temperature at this condition was about 565 kelvins above the nominal inlet air temperature and decreased to 505 kelvins above with increasing combustor pressure. Tests to determine the isothermal total pressure loss of the combustor showed a liner loss of 1.1 percent and a system loss of 6.5 percent.

  20. Computational Combustion

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Westbrook, C K; Mizobuchi, Y; Poinsot, T J

    2004-08-26

    Progress in the field of computational combustion over the past 50 years is reviewed. Particular attention is given to those classes of models that are common to most system modeling efforts, including fluid dynamics, chemical kinetics, liquid sprays, and turbulent flame models. The developments in combustion modeling are placed into the time-dependent context of the accompanying exponential growth in computer capabilities and Moore's Law. Superimposed on this steady growth, the occasional sudden advances in modeling capabilities are identified and their impacts are discussed. Integration of submodels into system models for spark ignition, diesel and homogeneous charge, compression ignition engines, surfacemore » and catalytic combustion, pulse combustion, and detonations are described. Finally, the current state of combustion modeling is illustrated by descriptions of a very large jet lifted 3D turbulent hydrogen flame with direct numerical simulation and 3D large eddy simulations of practical gas burner combustion devices.« less

  1. Advancements in Dual-Pump Broadband CARS for Supersonic Combustion Measurements

    NASA Technical Reports Server (NTRS)

    Tedder, Sarah Augusta Umberger

    2010-01-01

    Space- and time-resolved measurements of temperature and species mole fractions of nitrogen, oxygen, and hydrogen were obtained with a dual-pump coherent anti-Stokes Raman spectroscopy (CARS) system in hydrogen-fueled supersonic combustion free jet flows. These measurements were taken to provide time-resolved fluid properties of turbulent supersonic combustion for use in the creation and verification of computational fluid dynamic (CFD) models. CFD models of turbulent supersonic combustion flow currently facilitate the design of air-breathing supersonic combustion ramjet (scramjet) engines. Measurements were made in supersonic axi-symmetric free jets of two scales. First, the measurement system was tested in a laboratory environment using a laboratory-scale burner (approx.10 mm at nozzle exit). The flow structures of the laboratory-burner were too small to be resolved with the CARS measurements volume, but the composition and temperature of the jet allowed the performance of the system to be evaluated. Subsequently, the system was tested in a burner that was approximately 6 times larger, whose length scales are better resolved by the CARS measurement volume. During both these measurements, weaknesses of the CARS system, such as sensitivity to vibrations and beam steering and inability to measure temperature or species concentrations in hydrogen fuel injection regions were indentified. Solutions were then implemented in improved CARS systems. One of these improved systems is a dual-pump broadband CARS technique called, Width Increased Dual-pump Enhanced CARS (WIDECARS). The two lowest rotational energy levels of hydrogen detectable by WIDECARS are H2 S(3) and H2 S(4). The detection of these lines gives the system the capability to measure temperature and species concentrations in regions of the flow containing pure hydrogen fuel at room temperature. WIDECARS is also designed for measurements of all the major species (except water) in supersonic combustion flows

  2. A Low-Pressure Oxygen Storage System for Oxygen Supply in Low-Resource Settings.

    PubMed

    Rassool, Roger P; Sobott, Bryn A; Peake, David J; Mutetire, Bagayana S; Moschovis, Peter P; Black, Jim Fp

    2017-12-01

    Widespread access to medical oxygen would reduce global pneumonia mortality. Oxygen concentrators are one proposed solution, but they have limitations, in particular vulnerability to electricity fluctuations and failure during blackouts. The low-pressure oxygen storage system addresses these limitations in low-resource settings. This study reports testing of the system in Melbourne, Australia, and nonclinical field testing in Mbarara, Uganda. The system included a power-conditioning unit, a standard oxygen concentrator, and an oxygen store. In Melbourne, pressure and flows were monitored during cycles of filling/emptying, with forced voltage fluctuations. The bladders were tested by increasing pressure until they ruptured. In Mbarara, the system was tested by accelerated cycles of filling/emptying and then run on grid power for 30 d. The low-pressure oxygen storage system performed well, including sustaining a pressure approximately twice the standard working pressure before rupture of the outer bag. Flow of 1.2 L/min was continuously maintained to a simulated patient during 30 d on grid power, despite power failures totaling 2.9% of the total time, with durations of 1-176 min (mean 36.2, median 18.5). The low-pressure oxygen storage system was robust and durable, with accelerated testing equivalent to at least 2 y of operation revealing no visible signs of imminent failure. Despite power cuts, the system continuously provided oxygen, equivalent to the treatment of one child, for 30 d under typical power conditions for sub-Saharan Africa. The low-pressure oxygen storage system is ready for clinical field trials. Copyright © 2017 by Daedalus Enterprises.

  3. NCC: A Multidisciplinary Design/Analysis Tool for Combustion Systems

    NASA Technical Reports Server (NTRS)

    Liu, Nan-Suey; Quealy, Angela

    1999-01-01

    A multi-disciplinary design/analysis tool for combustion systems is critical for optimizing the low-emission, high-performance combustor design process. Based on discussions between NASA Lewis Research Center and the jet engine companies, an industry-government team was formed in early 1995 to develop the National Combustion Code (NCC), which is an integrated system of computer codes for the design and analysis of combustion systems. NCC has advanced features that address the need to meet designer's requirements such as "assured accuracy", "fast turnaround", and "acceptable cost". The NCC development team is comprised of Allison Engine Company (Allison), CFD Research Corporation (CFDRC), GE Aircraft Engines (GEAE), NASA Lewis Research Center (LeRC), and Pratt & Whitney (P&W). This development team operates under the guidance of the NCC steering committee. The "unstructured mesh" capability and "parallel computing" are fundamental features of NCC from its inception. The NCC system is composed of a set of "elements" which includes grid generator, main flow solver, turbulence module, turbulence and chemistry interaction module, chemistry module, spray module, radiation heat transfer module, data visualization module, and a post-processor for evaluating engine performance parameters. Each element may have contributions from several team members. Such a multi-source multi-element system needs to be integrated in a way that facilitates inter-module data communication, flexibility in module selection, and ease of integration.

  4. New potentials for conventional aircraft when powered by hydrogen-enriched gasoline

    NASA Technical Reports Server (NTRS)

    Menard, W. A.; Moynihan, P. I.; Rupe, J. H.

    1976-01-01

    Hydrogen enrichment for aircraft piston engines is under study in a new NASA program. The objective of the program is to determine the feasibility of inflight injection of hydrogen in general aviation aircraft engines to reduce fuel consumption and to lower emission levels. A catalytic hydrogen generator will be incorporated as part of the air induction system of a Lycoming turbocharged engine and will generate hydrogen by breaking down small amounts of the aviation gasoline used in the normal propulsion system. This hydrogen will then be mixed with gasoline and compressed air from the turbocharger before entering the engine combustion chamber. The paper summarizes the results of a systems analysis study. Calculations assuming a Beech Duke aircraft indicate that fuel savings on the order of 20% are possible. An estimate of the potential for the utilization of hydrogen enrichment to control exhaust emissions indicates that it may be possible to meet the 1979 Federal emission standards.

  5. Results from study of potential early commercial MHD power plants and from recent ETF design work. [Engineering Test Facility

    NASA Technical Reports Server (NTRS)

    Hals, F.; Kessler, R.; Swallom, D.; Westra, L.; Zar, J.; Morgan, W.; Bozzuto, C.

    1980-01-01

    The study deals with different 'moderate technology' entry-level commercial MHD power plants. Two of the reference plants are based on combustion of coal with air preheated in a high-temperature regenerative air heater separately fired with a low-BTU gas produced in a gasifier integrated with the power plant. The third reference plant design is based on the use of oxygen enriched combustion air. Performance calculations show that an overall power plant efficiency of the order of 44% can be reached with the use of oxygen enrichment.

  6. Chemical looping combustion: A new low-dioxin energy conversion technology.

    PubMed

    Hua, Xiuning; Wang, Wei

    2015-06-01

    Dioxin production is a worldwide concern because of its persistence and carcinogenic, teratogenic, and mutagenic effects. The pyrolysis-chemical looping combustion process of disposing solid waste is an alternative to traditional solid waste incineration developed to reduce the dioxin production. Based on the equilibrium composition of the Deacon reaction, pyrolysis gas oxidized by seven common oxygen carriers, namely, CuO, NiO, CaSO4, CoO, Fe2O3, Mn3O4, and FeTiO3, is studied and compared with the pyrolysis gas directly combusted by air. The result shows that the activity of the Deacon reaction for oxygen carriers is lower than that for air. For four typical oxygen carriers (CuO, NiO, Fe2O3, and FeTiO3), the influences of temperature, pressure, gas composition, and tar on the Deacon reaction are discussed in detail. According to these simulation results, the dioxin production in China, Europe, the United States, and Japan is predicted for solid waste disposal by the pyrolysis-chemical looping combustion process. Thermodynamic analysis results in this paper show that chemical looping combustion can reduce dioxin production in the disposal of solid waste. Copyright © 2015. Published by Elsevier B.V.

  7. Numerical study of influence of molecular diffusion in the Mild combustion regime

    NASA Astrophysics Data System (ADS)

    Mardani, Amir; Tabejamaat, Sadegh; Ghamari, Mohsen

    2010-09-01

    In this paper, the importance of molecular diffusion versus turbulent transport in the moderate or intense low-oxygen dilution (Mild) combustion mode has been numerically studied. The experimental conditions of Dally et al. [Proc. Combust. Inst. 29 (2002) 1147-1154] were used for modelling. The EDC model was used to describe the turbulence-chemistry interaction. The DRM-22 reduced mechanism and the GRI 2.11 full mechanism were used to represent the chemical reactions of an H2/methane jet flame. The importance of molecular diffusion for various O2 levels, jet Reynolds numbers and H2 fuel contents was investigated. Results show that the molecular diffusion in Mild combustion cannot be ignored in comparison with the turbulent transport. Also, the method of inclusion of molecular diffusion in combustion modelling has a considerable effect on the accuracy of numerical modelling of Mild combustion. By decreasing the jet Reynolds number, decreasing the oxygen concentration in the airflow or increasing H2 in the fuel mixture, the influence of molecular diffusion on Mild combustion increases.

  8. Detection and control of combustion instability based on the concept of dynamical system theory.

    PubMed

    Gotoda, Hiroshi; Shinoda, Yuta; Kobayashi, Masaki; Okuno, Yuta; Tachibana, Shigeru

    2014-02-01

    We propose an online method of detecting combustion instability based on the concept of dynamical system theory, including the characterization of the dynamic behavior of combustion instability. As an important case study relevant to combustion instability encountered in fundamental and practical combustion systems, we deal with the combustion dynamics close to lean blowout (LBO) in a premixed gas-turbine model combustor. The relatively regular pressure fluctuations generated by thermoacoustic oscillations transit to low-dimensional intermittent chaos owing to the intermittent appearance of burst with decreasing equivalence ratio. The translation error, which is characterized by quantifying the degree of parallelism of trajectories in the phase space, can be used as a control variable to prevent LBO.

  9. Detection and control of combustion instability based on the concept of dynamical system theory

    NASA Astrophysics Data System (ADS)

    Gotoda, Hiroshi; Shinoda, Yuta; Kobayashi, Masaki; Okuno, Yuta; Tachibana, Shigeru

    2014-02-01

    We propose an online method of detecting combustion instability based on the concept of dynamical system theory, including the characterization of the dynamic behavior of combustion instability. As an important case study relevant to combustion instability encountered in fundamental and practical combustion systems, we deal with the combustion dynamics close to lean blowout (LBO) in a premixed gas-turbine model combustor. The relatively regular pressure fluctuations generated by thermoacoustic oscillations transit to low-dimensional intermittent chaos owing to the intermittent appearance of burst with decreasing equivalence ratio. The translation error, which is characterized by quantifying the degree of parallelism of trajectories in the phase space, can be used as a control variable to prevent LBO.

  10. The E-3 Test Facility at Stennis Space Center: Research and Development Testing for Cryogenic and Storable Propellant Combustion Systems

    NASA Technical Reports Server (NTRS)

    Pazos, John T.; Chandler, Craig A.; Raines, Nickey G.

    2009-01-01

    This paper will provide the reader a broad overview of the current upgraded capabilities of NASA's John C. Stennis Space Center E-3 Test Facility to perform testing for rocket engine combustion systems and components using liquid and gaseous oxygen, gaseous and liquid methane, gaseous hydrogen, hydrocarbon based fuels, hydrogen peroxide, high pressure water and various inert fluids. Details of propellant system capabilities will be highlighted as well as their application to recent test programs and accomplishments. Data acquisition and control, test monitoring, systems engineering and test processes will be discussed as part of the total capability of E-3 to provide affordable alternatives for subscale to full scale testing for many different requirements in the propulsion community.

  11. Sulfur evolution in chemical looping combustion of coal with MnFe2O4 oxygen carrier.

    PubMed

    Wang, Baowen; Gao, Chuchang; Wang, Weishu; Zhao, Haibo; Zheng, Chuguang

    2014-05-01

    Chemical looping combustion (CLC) of coal has gained increasing attention as a novel combustion technology for its advantages in CO2 capture. Sulfur evolution from coal causes great harm from either the CLC operational or environmental perspective. In this research, a combined MnFe2O4 oxygen carrier (OC) was synthesized and its reaction with a typical Chinese high sulfur coal, Liuzhi (LZ) bituminous coal, was performed in a thermogravimetric analyzer (TGA)-Fourier transform infrared (FT-IR) spectrometer. Evolution of sulfur species during reaction of LZ coal with MnFe2O4 OC was systematically investigated through experimental means combined with thermodynamic simulation. TGA-FTIR analysis of the LZ reaction with MnFe2O4 indicated MnFe2O4 exhibited the desired superior reactivity compared to the single reference oxides Mn3O4 or Fe2O3, and SO2 produced was mainly related to oxidization of H2S by MnFe2O4. Experimental analysis of the LZ coal reaction with MnFe2O4, including X-ray diffraction and X-ray photoelectron spectroscopy analysis, verified that the main reduced counterparts of MnFe2O4 were Fe3O4 and MnO, in good agreement with the related thermodynamic simulation. The obtained MnO was beneficial to stabilize the reduced MnFe2O4 and avoid serious sintering, although the oxygen in MnO was not fully utilized. Meanwhile, most sulfur present in LZ coal was converted to solid MnS during LZ reaction with MnFe2O4, which was further oxidized to MnSO4. Finally, the formation of both MnS and such manganese silicates as Mn2SiO4 and MnSiO3 should be addressed to ensure the full regeneration of the reduced MnFe2O4. Copyright © 2014 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.

  12. System and method for reducing combustion dynamics in a combustor

    DOEpatents

    Uhm, Jong Ho; Johnson, Thomas Edward; Zuo, Baifang; York, William David

    2015-09-01

    A system for reducing combustion dynamics in a combustor includes an end cap having an upstream surface axially separated from a downstream surface, and tube bundles extend from the upstream surface through the downstream surface. A divider inside a tube bundle defines a diluent passage that extends axially through the downstream surface, and a diluent supply in fluid communication with the divider provides diluent flow to the diluent passage. A method for reducing combustion dynamics in a combustor includes flowing a fuel through tube bundles, flowing a diluent through a diluent passage inside a tube bundle, wherein the diluent passage extends axially through at least a portion of the end cap into a combustion chamber, and forming a diluent barrier in the combustion chamber between the tube bundle and at least one other adjacent tube bundle.

  13. Performance and Stability Characteristics of a Uni-Element Swirl Injector for Oxygen-Rich Stage Combustion Cycles

    NASA Technical Reports Server (NTRS)

    Pal, S.; Kalitan, D.; Woodward, R. D.; Santoro, R. J.

    2004-01-01

    A uni-element liquid propellant combustion performance and instability study for liquid RP-1 and hot oxygen-rich pre-burner products was conducted, at a chamber pressure of about 1000 psi. using flush and recessed swirl injectors. High-frequency pressure transducer measurements were analyzed to yield the characteristic frequencies which were compared to expected frequencies of the chamber. Modes, which were discovered to be present within the main chamber included, the first longitudinal, detected at approximately 1950 Hz, and the second longitudinal mode at approximately 3800 Hz. An additional first longitudinal quarter wave mode was measured at a frequency of approximately 23000 Hz for the recessed swirl injector configuration. The characteristic instabilities resulting from these experiments were relatively weak averaging 0.2% to 0.3% of the chamber pressure.

  14. Oxygen fires, materials compatibility and system contaminants

    NASA Astrophysics Data System (ADS)

    Barter, Simon A.; Hillen, Lance W.

    An evaluation is made of aircraft fires initiated by oxygen systems, giving attention to such systems' mechanical design and materials-selection factors. While many oxygen compatibility tests are conducted on single components, operational systems become contaminated through frequent use and occasional abuse; it is therefore essential for the designer to have information about the oxygen compatibility of the entire spectrum of potential contaminants and their various combinations. Valve designs are noted to be especially sensitive to system contamination. Gaseous oxygen fire severity is fundamentally determined by the period of oxygen flow. There is a clear need for an automatic shut-off device which would operate when abnormal flow conditions occur.

  15. Design and experimental investigation of an oxy-fuel combustion system for magnetohydrodynamic power extraction

    NASA Astrophysics Data System (ADS)

    Hernandez, Manuel Johannes

    A general consensus in the scientific and research community is the need to restrict carbon emissions in energy systems. Therefore, extensive research efforts are underway to develop the next generation of energy systems. In the field of power generation, researchers are actively investigating novel methods to produce electricity in a cleaner, efficient form. Recently, Oxy-Combustion for magnetohydrodynamic power extraction has generated significant interest, since the idea was proposed as a method for clean power generation in coal and natural gas power plants. Oxy-combustion technologies have been proposed to provide high enthalpy, electrically conductive flows for direct conversion of electricity. Direct power extraction via magnetohydrodynamics (MHD) can occur as a consequence of the motion of "seeded" combustion products in the presence of magnetic fields. However, oxy-combustion technologies for MHD power extraction has not been demonstrated in the available literature. Furthermore, there are still fundamental unexplored questions remaining, associated with this technology, for MHD power extraction. In this present study, previous magnetohydrodynamic combustion technologies and technical issues in this field were assessed to develop a new combustion system for electrically conductive flows. The research aims were to fully understand the current-state-of-the-art of open-cycle magnetohydrodynamic technologies and present new future directions and concepts. The design criteria, methodology, and technical specifications of an advanced cooled oxy-combustion technology are presented in this dissertation. The design was based on a combined analytical, empirical, and numerical approach. Analytical one-dimensional (1D) design tools initiated design construction. Design variants were analyzed and vetted against performance criteria through the application of computational fluid dynamics modeling. CFD-generated flow fields permitted insightful visualization of the

  16. A Novel Layered Sedimentary Rocks Structure of the Oxygen-Enriched Carbon for Ultrahigh-Rate-Performance Supercapacitors.

    PubMed

    Zhang, Lin-Lin; Li, Huan-Huan; Shi, Yan-Hong; Fan, Chao-Ying; Wu, Xing-Long; Wang, Hai-Feng; Sun, Hai-Zhu; Zhang, Jing-Ping

    2016-02-17

    In this paper, gelatin as a natural biomass was selected to successfully prepare an oxygen-enriched carbon with layered sedimentary rocks structure, which exhibited ultrahigh-rate performance and excellent cycling stability as supercapacitors. The specific capacitance reached 272.6 F g(-1) at 1 A g(-1) and still retained 197.0 F g(-1) even at 100 A g(-1) (with high capacitance retention of 72.3%). The outstanding electrochemical performance resulted from the special layered structure with large surface area (827.8 m(2) g(-1)) and high content of oxygen (16.215 wt %), which effectively realized the synergistic effects of the electrical double-layer capacitance and pseudocapacitance. Moreover, it delivered an energy density of 25.3 Wh kg(-1) even with a high power density of 34.7 kW kg(-1) and ultralong cycling stability (with no capacitance decay even over 10,000 cycles at 2 A g(-1)) in a symmetric supercapacitor, which are highly desirable for their practical application in energy storage devices and conversion.

  17. Controlled temperature expansion in oxygen production by molten alkali metal salts

    DOEpatents

    Erickson, Donald C.

    1985-06-04

    A continuous process is set forth for the production of oxygen from an oxygen containing gas stream, such as air, by contacting a feed gas stream with a molten solution of an oxygen acceptor to oxidize the acceptor and cyclically regenerating the oxidized acceptor by releasing oxygen from the acceptor wherein the oxygen-depleted gas stream from the contact zone is treated sequentially to temperature reduction by heat exchange against the feed stream so as to condense out entrained oxygen acceptor for recycle to the process, combustion of the gas stream with fuel to elevate its temperature and expansion of the combusted high temperature gas stream in a turbine to recover power.

  18. Controlled temperature expansion in oxygen production by molten alkali metal salts

    DOEpatents

    Erickson, D.C.

    1985-06-04

    A continuous process is set forth for the production of oxygen from an oxygen containing gas stream, such as air, by contacting a feed gas stream with a molten solution of an oxygen acceptor to oxidize the acceptor and cyclically regenerating the oxidized acceptor by releasing oxygen from the acceptor wherein the oxygen-depleted gas stream from the contact zone is treated sequentially to temperature reduction by heat exchange against the feed stream so as to condense out entrained oxygen acceptor for recycle to the process, combustion of the gas stream with fuel to elevate its temperature and expansion of the combusted high temperature gas stream in a turbine to recover power. 1 fig.

  19. Spectral modeling of radiation in combustion systems

    NASA Astrophysics Data System (ADS)

    Pal, Gopalendu

    Radiation calculations are important in combustion due to the high temperatures encountered but has not been studied in sufficient detail in the case of turbulent flames. Radiation calculations for such problems require accurate, robust, and computationally efficient models for the solution of radiative transfer equation (RTE), and spectral properties of radiation. One more layer of complexity is added in predicting the overall heat transfer in turbulent combustion systems due to nonlinear interactions between turbulent fluctuations and radiation. The present work is aimed at the development of finite volume-based high-accuracy thermal radiation modeling, including spectral radiation properties in order to accurately capture turbulence-radiation interactions (TRI) and predict heat transfer in turbulent combustion systems correctly and efficiently. The turbulent fluctuations of temperature and chemical species concentrations have strong effects on spectral radiative intensities, and TRI create a closure problem when the governing partial differential equations are averaged. Recently, several approaches have been proposed to take TRI into account. Among these attempts the most promising approaches are the probability density function (PDF) methods, which can treat nonlinear coupling between turbulence and radiative emission exactly, i.e., "emission TRI". The basic idea of the PDF method is to treat physical variables as random variables and to solve the PDF transport equation stochastically. The actual reacting flow field is represented by a large number of discrete stochastic particles each carrying their own random variable values and evolving with time. The mean value of any function of those random variables, such as the chemical source term, can be evaluated exactly by taking the ensemble average of particles. The local emission term belongs to this class and thus, can be evaluated directly and exactly from particle ensembles. However, the local absorption term

  20. Solar Energy Systems for Lunar Oxygen Generation

    NASA Technical Reports Server (NTRS)

    Colozza, Anthony J.; Heller, Richard S.; Wong, Wayne A.; Hepp, Aloysius F.

    2010-01-01

    An evaluation of several solar concentrator-based systems for producing oxygen from lunar regolith was performed. The systems utilize a solar concentrator mirror to provide thermal energy for the oxygen production process. Thermal energy to power a Stirling heat engine and photovoltaics are compared for the production of electricity. The electricity produced is utilized to operate the equipment needed in the oxygen production process. The initial oxygen production method utilized in the analysis is hydrogen reduction of ilmenite. Utilizing this method of oxygen production a baseline system design was produced. This baseline system had an oxygen production rate of 0.6 kg/hr with a concentrator mirror size of 5 m. Variations were performed on the baseline design to show how changes in the system size and process (rate) affected the oxygen production rate. An evaluation of the power requirements for a carbothermal lunar regolith reduction reactor has also been conducted. The reactor had a total power requirement between 8,320 to 9,961 W when producing 1000 kg/year of oxygen. The solar concentrator used to provide the thermal power (over 82 percent of the total energy requirement) would have a diameter of less than 4 m.

  1. Handbook of infrared radiation from combustion gases

    NASA Technical Reports Server (NTRS)

    Ludwig, C. B.; Malkmus, W.; Reardon, J. E.; Thomson, J. A. L.; Goulard, R. (Editor)

    1973-01-01

    The treatment of radiant emission and absorption by combustion gases are discussed. Typical applications include: (1) rocket combustion chambers and exhausts, (2) turbojet engines and exhausts, and (3) industrial furnaces. Some mention is made of radiant heat transfer problems in planetary atmospheres, in stellar atmospheres, and in reentry plasmas. Particular consideration is given to the temperature range from 500K to 3000K and the pressure range from 0.001 atmosphere to 30 atmospheres. Strong emphasis is given to the combustion products of hydrocarbon fuels with oxygen, specifically to carbon dioxide, water vapor, and carbon monoxide. In addition, species such as HF, HC1, CN, OH, and NO are treated.

  2. Seventh International Workshop on Microgravity Combustion and Chemically Reacting Systems. Rev. 1

    NASA Technical Reports Server (NTRS)

    Sacksteder, Kurt (Compiler)

    2003-01-01

    The Seventh International Workshop on Microgravity Combustion and Chemically Reacting Systems was planned for June 3-6, 2003, in Cleveland, Ohio, near the NASA John H. Glenn Research Center at Lewis Field. The new name for the workshop is based on the decision to broaden our scope to encompass support for future space exploration through basic and applied research in reacting systems that in some cases may not look like combustion. The workshop has been lengthened to 4 days with focus sessions on spacecraft fire safety and exploration-related research. We believe that the microgravity combustion science community is almost uniquely positioned to make substantial contributions to this new effort.

  3. Staged fluidized-bed combustion and filter system

    DOEpatents

    Mei, Joseph S.; Halow, John S.

    1994-01-01

    A staged fluidized-bed combustion and filter system for substantially reducing the quantity of waste through the complete combustion into ash-type solids and gaseous products. The device has two fluidized-bed portions, the first primarily as a combustor/pyrolyzer bed, and the second as a combustor/filter bed. The two portions each have internal baffles to define stages so that material moving therein as fluidized beds travel in an extended route through those stages. Fluidization and movement is achieved by the introduction of gases into each stage through a directional nozzle. Gases produced in the combustor/pyrolyzer bed are permitted to travel into corresponding stages of the combustor/filter bed through screen filters that permit gas flow but inhibit solids flow. Any catalyst used in the combustor/filter bed is recycled. The two beds share a common wall to minimize total volume of the system. A slightly modified embodiment can be used for hot gas desulfurization and sorbent regeneration. Either side-by-side rectangular beds or concentric beds can be used. The system is particularly suited to the processing of radioactive and chemically hazardous waste.

  4. High-throughput simultaneous determination of plasma water deuterium and 18-oxygen enrichment using a high-temperature conversion elemental analyzer with isotope ratio mass spectrometry.

    PubMed

    Richelle, M; Darimont, C; Piguet-Welsch, C; Fay, L B

    2004-01-01

    This paper presents a high-throughput method for the simultaneous determination of deuterium and oxygen-18 (18O) enrichment of water samples isolated from blood. This analytical method enables rapid and simple determination of these enrichments of microgram quantities of water. Water is converted into hydrogen and carbon monoxide gases by the use of a high-temperature conversion elemental analyzer (TC-EA), that are then transferred on-line into the isotope ratio mass spectrometer. Accuracy determined with the standard light Antartic precipitation (SLAP) and Greenland ice sheet precipitation (GISP) is reliable for deuterium and 18O enrichments. The range of linearity is from 0 up to 0.09 atom percent excess (APE, i.e. -78 up to 5725 delta per mil (dpm)) for deuterium enrichment and from 0 up to 0.17 APE (-11 up to 890 dpm) for 18O enrichment. Memory effects do exist but can be avoided by analyzing the biological samples in quintuplet. This method allows the determination of 1440 samples per week, i.e. 288 biological samples per week. Copyright 2004 John Wiley & Sons, Ltd.

  5. System and method for reducing combustion dynamics in a combustor

    DOEpatents

    Uhm, Jong Ho; Johnson, Thomas Edward; Zuo, Baifang; York, William David

    2013-08-20

    A system for reducing combustion dynamics in a combustor includes an end cap having an upstream surface axially separated from a downstream surface, and tube bundles extend through the end cap. A diluent supply in fluid communication with the end cap provides diluent flow to the end cap. Diluent distributors circumferentially arranged inside at least one tube bundle extend downstream from the downstream surface and provide fluid communication for the diluent flow through the end cap. A method for reducing combustion dynamics in a combustor includes flowing fuel through tube bundles that extend axially through an end cap, flowing a diluent through diluent distributors into a combustion chamber, wherein the diluent distributors are circumferentially arranged inside at least one tube bundle and each diluent distributor extends downstream from the end cap, and forming a diluent barrier in the combustion chamber between at least one pair of adjacent tube bundles.

  6. LOX/Hydrocarbon Combustion Instability Investigation

    NASA Technical Reports Server (NTRS)

    Jensen, R. J.; Dodson, H. C.; Claflin, S. E.

    1989-01-01

    The LOX/Hydrocarbon Combustion Instability Investigation Program was structured to determine if the use of light hydrocarbon combustion fuels with liquid oxygen (LOX) produces combustion performance and stability behavior similar to the LOX/hydrogen propellant combination. In particular methane was investigated to determine if that fuel can be rated for combustion instability using the same techniques as previously used for LOX/hydrogen. These techniques included fuel temperature ramping and stability bomb tests. The hot fire program probed the combustion behavior of methane from ambient to subambient temperatures. Very interesting results were obtained from this program that have potential importance to future LOX/methane development programs. A very thorough and carefully reasoned documentation of the experimental data obtained is contained. The hot fire test logic and the associated tests are discussed. Subscale performance and stability rating testing was accomplished using 40,000 lb. thrust class hardware. Stability rating tests used both bombs and fuel temperature ramping techniques. The test program was successful in generating data for the evaluation of the methane stability characteristics relative to hydrogen and to anchor stability models. Data correlations, performance analysis, stability analyses, and key stability margin enhancement parameters are discussed.

  7. Closed loop air cooling system for combustion turbines

    DOEpatents

    Huber, David John; Briesch, Michael Scot

    1998-01-01

    Convective cooling of turbine hot parts using a closed loop system is disclosed. Preferably, the present invention is applied to cooling the hot parts of combustion turbine power plants, and the cooling provided permits an increase in the inlet temperature and the concomitant benefits of increased efficiency and output. In preferred embodiments, methods and apparatus are disclosed wherein air is removed from the combustion turbine compressor and delivered to passages internal to one or more of a combustor and turbine hot parts. The air cools the combustor and turbine hot parts via convection and heat is transferred through the surfaces of the combustor and turbine hot parts.

  8. Closed loop air cooling system for combustion turbines

    DOEpatents

    Huber, D.J.; Briesch, M.S.

    1998-07-21

    Convective cooling of turbine hot parts using a closed loop system is disclosed. Preferably, the present invention is applied to cooling the hot parts of combustion turbine power plants, and the cooling provided permits an increase in the inlet temperature and the concomitant benefits of increased efficiency and output. In preferred embodiments, methods and apparatus are disclosed wherein air is removed from the combustion turbine compressor and delivered to passages internal to one or more of a combustor and turbine hot parts. The air cools the combustor and turbine hot parts via convection and heat is transferred through the surfaces of the combustor and turbine hot parts. 1 fig.

  9. Bulk oxygen vacancies enriched TiO2 and its enhanced visible photocatalytic performance

    NASA Astrophysics Data System (ADS)

    Xu, Liming; Ma, Xujun; Sun, Na; Chen, Feng

    2018-05-01

    Via a vacuum thermal treatment, oxygen vacancy (Ov) was introduced into TiO2 bulk lattice during the phase transformation from amorphous TiO2 to anatase. High-resolution transmission electron microscopy (HRTEM), Raman spectra and X-ray diffraction (XRD) confirm the involvement of Ov causes more violent changes in both bulk and surface structure. Electron paramagnetic resonance (EPR) demonstrated as-obtained V350 gets about a 40-times enhanced Ov signal compared with pure TiO2 (A350) and a 10-times larger signal than that of common Ov modified TiO2 (A450-V350), which clearly illustrates the high concentration of Ov in its bulk lattice. The much enriched Ovs in both bulk and surface lattices of TiO2 help V350 get an enhanced capacity in either visible light harvest or photocarriers generation. And a much higher visible photocatalytic activity for Aicd Orange 7 degradation was finally achieved by V350.

  10. Low emission U-fired boiler combustion system

    DOEpatents

    Ake, Terence; Beittel, Roderick; Lisauskas, Robert A.; Reicker, Eric

    2000-01-01

    At least one main combustion chamber contains at least one pulverized coal burner. Each pulverized coal burner is operatively arranged for minimizing NO.sub.X production and for maintaining a predetermined operating temperature to liquefy ash within the combustion chamber. The combustion chamber includes a slag drain for removing slag from the combustion chamber. A slag screen is positioned in a generally U-shaped furnace flow pattern. The slag screen is positioned between the combustion chamber and a radiant furnace. The radiant furnace includes a reburning zone for in-furnace No.sub.X reduction. The reburning zone extends between a reburning fuel injection source and at least one overfire air injection port for injecting air.

  11. Selective enrichment of a methanol-utilizing consortium using pulp & paper mill waste streams

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Gregory R. Mockos; William A. Smith; Frank J. Loge

    Efficient utilization of carbon inputs is critical to the economic viability of the current forest products sector. Input carbon losses occur in various locations within a pulp mill, including losses as volatile organics and wastewater . Opportunities exist to capture this carbon in the form of value-added products such as biodegradable polymers. Waste activated sludge from a pulp mill wastewater facility was enriched for 80 days for a methanol-utilizing consortium with the goal of using this consortium to produce biopolymers from methanol-rich pulp mill waste streams. Five enrichment conditions were utilized: three high-methanol streams from the kraft mill foul condensatemore » system, one methanol-amended stream from the mill wastewater plant, and one methanol-only enrichment. Enrichment reactors were operated aerobically in sequencing batch mode at neutral pH and 25°C with a hydraulic residence time and a solids retention time of four days. Non-enriched waste activated sludge did not consume methanol or reduce chemical oxygen demand. With enrichment, however, the chemical oxygen demand reduction over 24 hour feed/decant cycles ranged from 79 to 89 %, and methanol concentrations dropped below method detection limits. Neither the non-enriched waste activated sludge nor any of the enrichment cultures accumulated polyhydroxyalkanoates (PHAs) under conditions of nitrogen sufficiency. Similarly, the non-enriched waste activated sludge did not accumulate PHAs under nitrogen limited conditions. By contrast, enriched cultures accumulated PHAs to nearly 14% on a dry weight basis under nitrogen limited conditions. This indicates that selectively-enriched pulp mill waste activated sludge can serve as an inoculum for PHA production from methanol-rich pulp mill effluents.« less

  12. Device and method for separating oxygen isotopes

    DOEpatents

    Rockwood, Stephen D.; Sander, Robert K.

    1984-01-01

    A device and method for separating oxygen isotopes with an ArF laser which produces coherent radiation at approximately 193 nm. The output of the ArF laser is filtered in natural air and applied to an irradiation cell where it preferentially photodissociates molecules of oxygen gas containing .sup.17 O or .sup.18 O oxygen nuclides. A scavenger such as O.sub.2, CO or ethylene is used to collect the preferentially dissociated oxygen atoms and recycled to produce isotopically enriched molecular oxygen gas. Other embodiments utilize an ArF laser which is narrowly tuned with a prism or diffraction grating to preferentially photodissociate desired isotopes. Similarly, desired mixtures of isotopic gas can be used as a filter to photodissociate enriched preselected isotopes of oxygen.

  13. Gasdynamic modeling and parametric study of mesoscale internal combustion swing engine/generator systems

    NASA Astrophysics Data System (ADS)

    Gu, Yongxian

    The demand of portable power generation systems for both domestic and military applications has driven the advances of mesoscale internal combustion engine systems. This dissertation was devoted to the gasdynamic modeling and parametric study of the mesoscale internal combustion swing engine/generator systems. First, the system-level thermodynamic modeling for the swing engine/generator systems has been developed. The system performance as well as the potentials of both two- and four-stroke swing engine systems has been investigated based on this model. Then through parameterc studies, the parameters that have significant impacts on the system performance have been identified, among which, the burn time and spark advance time are the critical factors related to combustion process. It is found that the shorter burn time leads to higher system efficiency and power output and the optimal spark advance time is about half of the burn time. Secondly, the turbulent combustion modeling based on levelset method (G-equation) has been implemented into the commercial software FLUENT. Thereafter, the turbulent flame propagation in a generic mesoscale combustion chamber and realistic swing engine chambers has been studied. It is found that, in mesoscale combustion engines, the burn time is dominated by the mean turbulent kinetic energy in the chamber. It is also shown that in a generic mesoscale combustion chamber, the burn time depends on the longest distance between the initial ignition kernel to its walls and by changing the ignition and injection locations, the burn time can be reduced by a factor of two. Furthermore, the studies of turbulent flame propagation in real swing engine chambers show that the combustion can be enhanced through in-chamber turbulence augmentation and with higher engine frequency, the burn time is shorter, which indicates that the in-chamber turbulence can be induced by the motion of moving components as well as the intake gas jet flow. The burn time

  14. Future fundamental combustion research for aeropropulsion systems

    NASA Technical Reports Server (NTRS)

    Mularz, E. J.

    1985-01-01

    Physical fluid mechanics, heat transfer, and chemical kinetic processes which occur in the combustion chamber of aeropropulsion systems were investigated. With the component requirements becoming more severe for future engines, the current design methodology needs the new tools to obtain the optimum configuration in a reasonable design and development cycle. Research efforts in the last few years were encouraging but to achieve these benefits research is required into the fundamental aerothermodynamic processes of combustion. It is recommended that research continues in the areas of flame stabilization, combustor aerodynamics, heat transfer, multiphase flow and atomization, turbulent reacting flows, and chemical kinetics. Associated with each of these engineering sciences is the need for research into computational methods to accurately describe and predict these complex physical processes. Research needs in each of these areas are highlighted.

  15. Dual-reporter surrogate systems for efficient enrichment of genetically modified cells.

    PubMed

    Ren, Chonghua; Xu, Kun; Liu, Zhongtian; Shen, Juncen; Han, Furong; Chen, Zhilong; Zhang, Zhiying

    2015-07-01

    Isolation of genetically modified cells generated by designed nucleases are challenging, since they are often phenotypically indistinguishable from their parental cells. To efficiently enrich genetically modified cells, we developed two dual-reporter surrogate systems, namely NHEJ-RPG and SSA-RPG based on NHEJ and SSA repair mechanisms, respectively. Repair and enrichment efficiencies of these two systems were compared using different nucleases. In both CRISPR-Cas9- and ZFNs-induced DSB repair studies, we found that the efficiency and sensitivity of the SSA-RPG reporter with direct repeat length more than 200 bp were much higher than the NHEJ-RPG reporter. By utilizing the SSA-RPG reporter, we achieved the enrichment for indels in several endogenous loci with 6.3- to 34.8-fold of non-selected cells. Thus, the highly sensitive SSA-RPG reporter can be used for activity validation of designed nucleases and efficient enrichment of genetically modified cells. Besides, our systems offer alternative enrichment choices either by puromycin selection or FACS.

  16. Performance of PAHs emission from bituminous coal combustion.

    PubMed

    Yan, Jian-Hua; You, Xiao-Fang; Li, Xiao-Dong; Ni, Ming-Jiang; Yin, Xue-Feng; Cen, Ke-Fa

    2004-12-01

    Carcinogenic and mutagenic polycyclic aromatic hydrocarbons (PAHs) generated in coal combustion have caused great environmental health concern. Seventeen PAHs (16 high priority PAHs recommended by USEPA plus Benzo[e]pyrene) present in five raw bituminous coals and released during bituminous coal combustion were studied. The effects of combustion temperature, gas atmosphere, and chlorine content of raw coal on PAHs formation were investigated. Two additives (copper and cupric oxide) were added when the coal was burned. The results indicated that significant quantities of PAHs were produced from incomplete combustion of coal pyrolysis products at high temperature, and that temperature is an important causative factor of PAHs formation. PAHs concentrations decrease with the increase of chlorine content in oxygen or in nitrogen atmosphere. Copper and cupric oxide additives can promote PAHs formation (especially the multi-ring PAHs) during coal combustion.

  17. Droplet Combustion Experiment Operates

    NASA Technical Reports Server (NTRS)

    2003-01-01

    Fuel ignites and burns in the Droplet Combustion Experiment (DCE) on STS-94 on July 12, 1997, MET:11/07:00 (approximate). DCE used various fuels -- in drops ranging from 1 mm (0.04 inches) to 5 mm (0.2 inches) -- and mixtures of oxidizers and inert gases to learn more about the physics of combustion in the simplest burning configuration, a sphere. The DCE was designed to investigate the fundamental combustion aspects of single, isolated droplets under different pressures and ambient oxygen concentrations for a range of droplet sizes varying between 2 and 5 mm. The experiment elapsed time is shown at the bottom of the composite image. The DCE principal investigator was Forman Williams, University of California, San Diego. The experiment was part of the space research investigations conducted during the Microgravity Science Laboratory-1R mission (STS-94, July 1-17 1997). Advanced combustion experiments will be a part of investigations plarned for the International Space Station. (119KB JPEG, 658 x 982 pixels; downlinked video, higher quality not available) The MPG from which this composite was made is available at http://mix.msfc.nasa.gov/ABSTRACTS/MSFC-0300171.html.

  18. Combustion Fundamentals Research

    NASA Technical Reports Server (NTRS)

    1983-01-01

    Increased emphasis is placed on fundamental and generic research at Lewis Research Center with less systems development efforts. This is especially true in combustion research, where the study of combustion fundamentals has grown significantly in order to better address the perceived long term technical needs of the aerospace industry. The main thrusts for this combustion fundamentals program area are as follows: analytical models of combustion processes, model verification experiments, fundamental combustion experiments, and advanced numeric techniques.

  19. A comprehensive evaluation of the influence of air combustion and oxy-fuel combustion flue gas constituents on Hg(0) re-emission in WFGD systems.

    PubMed

    Ochoa-González, Raquel; Díaz-Somoano, Mercedes; Martínez-Tarazona, M Rosa

    2014-07-15

    This paper evaluates the influence of the main constituents of flue gases from coal combustion (CO2, O2, N2 and water vapor), in air and oxy-fuel combustion conditions on the re-emission of Hg(0) in wet scrubbers. It was observed that the concentration of water vapor does not affect the re-emission of mercury, whereas O2 and CO2 have a notable influence. High concentrations of O2 in the flue gas prevent the re-emission of Hg(0) due to the reaction of oxygen with the metals present in low oxidation states. High concentrations of CO2, which cause a decrease in the pH and the redox potential of gypsum slurries, reduce the amount of Hg(0) that is re-emitted. As a consequence, the high content of CO2 in oxy-fuel combustion may decrease the re-emission of Hg(0) due to the solubility of CO2 in the suspension and the decrease in the pH. It was also found that O2 affects the stabilization of Hg(2+) species in gypsum slurries. The results of this study confirm that the amount of metals present in limestone as well as the redox potential and pH of the slurries in wet desulphurization plants need to be strictly controlled to reduce Hg(0) re-emissions from power plants operating under oxy-fuel combustion conditions. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. Torrefaction of empty fruit bunches under biomass combustion gas atmosphere.

    PubMed

    Uemura, Yoshimitsu; Sellappah, Varsheta; Trinh, Thanh Hoai; Hassan, Suhaimi; Tanoue, Ken-Ichiro

    2017-11-01

    Torrefaction of oil palm empty fruit bunches (EFB) under combustion gas atmosphere was conducted in a batch reactor at 473, 523 and 573K in order to investigate the effect of real combustion gas on torrefaction behavior. The solid mass yield of torrefaction in combustion gas was smaller than that of torrefaction in nitrogen. This may be attributed to the decomposition enhancement effect by oxygen and carbon dioxide in combustion gas. Under combustion gas atmosphere, the solid yield for torrefaction of EFB became smaller as the temperature increased. The representative products of combustion gas torrefaction were carbon dioxide and carbon monoxide (gas phase) and water, phenol and acetic acid (liquid phase). By comparing torrefaction in combustion gas with torrefaction in nitrogen gas, it was found that combustion gas can be utilized as torrefaction gas to save energy and inert gas. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Japanese RDF-fired power generation system and fundamental research on RDF combustion

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Narukawa, Kimihito; Goto, Hidenori; Chen, Y.

    1997-12-31

    Power generation from refuse derived fuel (RDF) is one of the new technologies for municipal solid waste (MSW) management. This technology is strongly attracting the attention of the Japanese government. The results of a feasibility study of this system in Japan is presented. To develop this highly efficient RDF-fired CFB generating process, combustibility and dechlorination characteristics of RDF were investigated by both the thermo-balance technique and combustion tests with an electric furnace. RDF combustion tests by a bench scale CFBC were carried out and then the following experimental results were obtained: (1) RDF can be combusted almost completely even inmore » small scale CFBC; (2) HCl and N{sub 2}O emissions are quite low at any conditions; and (3) NO{sub x} emissions are a little higher in single stage combustion, however they are reduced at 50% air bias ratio. Some of the results can be explained by a RDF combustion model.« less

  2. Vapor hydrogen and oxygen isotopes reflect water of combustion in the urban atmosphere.

    PubMed

    Gorski, Galen; Strong, Courtenay; Good, Stephen P; Bares, Ryan; Ehleringer, James R; Bowen, Gabriel J

    2015-03-17

    Anthropogenic modification of the water cycle involves a diversity of processes, many of which have been studied intensively using models and observations. Effective tools for measuring the contribution and fate of combustion-derived water vapor in the atmosphere are lacking, however, and this flux has received relatively little attention. We provide theoretical estimates and a first set of measurements demonstrating that water of combustion is characterized by a distinctive combination of H and O isotope ratios. We show that during periods of relatively low humidity and/or atmospheric stagnation, this isotopic signature can be used to quantify the concentration of water of combustion in the atmospheric boundary layer over Salt Lake City. Combustion-derived vapor concentrations vary between periods of atmospheric stratification and mixing, both on multiday and diurnal timescales, and respond over periods of hours to variations in surface emissions. Our estimates suggest that up to 13% of the boundary layer vapor during the period of study was derived from combustion sources, and both the temporal pattern and magnitude of this contribution were closely reproduced by an independent atmospheric model forced with a fossil fuel emissions data product. Our findings suggest potential for water vapor isotope ratio measurements to be used in conjunction with other tracers to refine the apportionment of urban emissions, and imply that water vapor emissions associated with combustion may be a significant component of the water budget of the urban boundary layer, with potential implications for urban climate, ecohydrology, and photochemistry.

  3. Oxygen cycling in the northern Benguela Upwelling System: Modelling oxygen sources and sinks

    NASA Astrophysics Data System (ADS)

    Schmidt, Martin; Eggert, Anja

    2016-12-01

    This paper elucidates the oxygen dynamics in the northern Benguela Upwelling System by means of process oriented, numerical modelling. Owing to the complex physical-biological interaction in this system, a coupled hydrodynamic-biogeochemical model is required to grasp the various aspects of the oxygen dynamics. We used high-resolution atmospheric fields derived from observations to force our model, available since 1999. The model results represent a 15 years, consistent data set of realistic hydrographic and ecosystem variables, including oxygen distribution patterns. After a concise description of the main aspects of the model, we use the model data to analyse the components contributing to the oxygen dynamics, namely, the ocean circulation, the exchange between ocean and atmosphere as well as the local biogeochemical oxygen cycling in the system. We thoroughly validate the model with available field observations and remote sensing data. The strengths of coastal upwelling, which controls the nutrient supply to the euphotic zone, as well as the poleward undercurrent that carries oxygen and nutrients to the shelf in the northern Benguela Upwelling System are well reproduced in the model. Among the biological oxygen sinks, mineralisation in the sediment, respiration of zooplankton and nitrification in the water column are important. We also found that vertical migration of zooplankton in response to the oxygen conditions provides a regulating feedback, which may prevent a complete deoxygenation of suboxic waters. As long as oxygen or nitrate are available in the bottom waters, the activities of chemolithoautotrophic sulphur bacteria on the sediment surface keep the redoxcline within the sediment and prevent the release of hydrogen sulphide into the water column. By horizontal integration of the simulated ocean-atmosphere oxygen flux, it can be shown that the Kunene upwelling cell between 16 ° S and 18 ° S is a boundary between the equatorial ocean, characterise by

  4. Updating the Conceptual Model for Fine Particle Mass Emissions from Combustion Systems Allen L. Robinson.

    PubMed

    Robinson, Allen L; Grieshop, Andrew P; Donahue, Neil M; Hunt, Sherri W

    2010-10-01

    Atmospheric transformations determine the contribution of emissions from combustion systems to fine particulate matter (PM) mass. For example, combustion systems emit vapors that condense onto existing particles or form new particles as the emissions are cooled and diluted. Upon entering the atmosphere, emissions are exposed to atmospheric oxidants and sunlight, which causes them to evolve chemically and physically, generating secondary PM. This review discusses these transformations, focusing on organic PM. Organic PM emissions are semi -volatile at atmospheric conditions and thus their partitioning varies continuously with changing temperature and concentration. Because organics contribute a large portion of the PM mass emitted by most combustion sources, these emissions cannot be represented using a traditional, static emission factor. Instead, knowledge of the volatility distribution of emissions is required to explicitly account for changes in gas-particle partitioning. This requires updating how PM emissions from combustion systems are measured and simulated from combustion systems. Secondary PM production often greatly exceeds the direct or primary PM emissions; therefore, secondary PM must be included in any assessment of the contribution of combustion systems to ambient PM concentrations. Low-volatility organic vapors emitted by combustion systems appear to be very important secondary PM precursors that are poorly accounted for in inventories and models. The review concludes by discussing the implications that the dynamic nature of these PM emissions have on source testing for emission inventory development and regulatory purposes. This discussion highlights important linkages between primary and secondary PM, which could lead to simplified certification test procedures while capturing the emission components that contribute most to atmospheric PM mass.

  5. Toxic-Waste Disposal by Combustion in Containers

    NASA Technical Reports Server (NTRS)

    Houseman, J.; Stephens, J. B.; Moynihan, P. I.; Compton, L. E.; Kalvinskas, J. J.

    1986-01-01

    Chemical wastes burned with minimal handling in storage containers. Technique for disposing of chemical munitions by burning them inside shells applies to disposal of toxic materials stored in drums. Fast, economical procedure overcomes heat-transfer limitations of conventional furnace designs by providing direct contact of oxygenrich combustion gases with toxic agent. No need to handle waste material, and container also decontaminated in process. Oxygen-rich torch flame cuts burster well and causes vaporization and combustion of toxic agent contained in shell.

  6. Fluidized-bed calciner with combustion nozzle and shroud

    DOEpatents

    Wielang, Joseph A.; Palmer, William B.; Kerr, William B.

    1977-01-01

    A nozzle employed as a burner within a fluidized bed is coaxially enclosed within a tubular shroud that extends beyond the nozzle length into the fluidized bed. The open-ended shroud portion beyond the nozzle end provides an antechamber for mixture and combustion of atomized fuel with an oxygen-containing gas. The arrangement provides improved combustion efficiency and excludes bed particles from the high-velocity, high-temperature portions of the flame to reduce particle attrition.

  7. Analysis of pressure spectra measurements in a ducted combustion system. Ph.D. Thesis - Toledo Univ.

    NASA Technical Reports Server (NTRS)

    Miles, J. H.

    1980-01-01

    Combustion noise propagation in an operating ducted liquid fuel combustion system is studied in relation to the development of combustion noise prediction and suppression techniques. The presence of combustor emissions in the duct is proposed as the primary mechanism producing the attenuation and dispersion of combustion noise propagating in an operating liquid fuel combustion system. First, a complex mathematical model for calculating attenuation and dispersion taking into account mass transfer, heat transfer, and viscosity effects due to the presence of liquid fuel droplets or solid soot particles is discussed. Next, a simpler single parameter model for calculating pressure auto-spectra and cross-spectra which takes into account dispersion and attenuation due to heat transfer between solid soot particles and air is developed. Then, auto-spectra and cross-spectra obtained from internal pressure measurements in a combustion system consisting of a J-47 combustor can, a spool piece, and a long duct are presented. Last, analytical results obtained with the single parameter model are compared with the experimental measurements. The single parameter model results are shown to be in excellent agreement with the measurements.

  8. Spatially monitoring oxygen level in 3D microfabricated cell culture systems using optical oxygen sensing beads

    PubMed Central

    Wang, Lin; Acosta, Miguel A.; Leach, Jennie B.; Carrier, Rebecca L.

    2013-01-01

    Capability of measuring and monitoring local oxygen concentration at the single cell level (tens of microns scale) is often desirable but difficult to achieve in cell culture. In this study, biocompatible oxygen sensing beads were prepared and tested for their potential for real-time monitoring and mapping of local oxygen concentration in 3D micro-patterned cell culture systems. Each oxygen sensing bead is composed of a silica core loaded with both an oxygen sensitive Ru(Ph2phen3)Cl2 dye and oxygen insensitive Nile blue reference dye, and a poly-dimethylsiloxane (PDMS) shell rendering biocompatibility. Human intestinal epithelial Caco-2 cells were cultivated on a series of PDMS and type I collagen based substrates patterned with micro-well arrays for 3 or 7 days, and then brought into contact with oxygen sensing beads. Using an image analysis algorithm to convert florescence intensity of beads to partial oxygen pressure in the culture system, tens of microns-size oxygen sensing beads enabled the spatial measurement of local oxygen concentration in the microfabricated system. Results generally indicated lower oxygen level inside wells than on top of wells, and local oxygen level dependence on structural features of cell culture surfaces. Interestingly, chemical composition of cell culture substrates also appeared to affect oxygen level, with type-I collagen based cell culture systems having lower oxygen concentration compared to PDMS based cell culture systems. In general, results suggest that oxygen sensing beads can be utilized to achieve real-time and local monitoring of micro-environment oxygen level in 3D microfabricated cell culture systems. PMID:23443975

  9. Spatially monitoring oxygen level in 3D microfabricated cell culture systems using optical oxygen sensing beads.

    PubMed

    Wang, Lin; Acosta, Miguel A; Leach, Jennie B; Carrier, Rebecca L

    2013-04-21

    Capability of measuring and monitoring local oxygen concentration at the single cell level (tens of microns scale) is often desirable but difficult to achieve in cell culture. In this study, biocompatible oxygen sensing beads were prepared and tested for their potential for real-time monitoring and mapping of local oxygen concentration in 3D micro-patterned cell culture systems. Each oxygen sensing bead is composed of a silica core loaded with both an oxygen sensitive Ru(Ph2phen3)Cl2 dye and oxygen insensitive Nile blue reference dye, and a poly-dimethylsiloxane (PDMS) shell rendering biocompatibility. Human intestinal epithelial Caco-2 cells were cultivated on a series of PDMS and type I collagen based substrates patterned with micro-well arrays for 3 or 7 days, and then brought into contact with oxygen sensing beads. Using an image analysis algorithm to convert florescence intensity of beads to partial oxygen pressure in the culture system, tens of microns-size oxygen sensing beads enabled the spatial measurement of local oxygen concentration in the microfabricated system. Results generally indicated lower oxygen level inside wells than on top of wells, and local oxygen level dependence on structural features of cell culture surfaces. Interestingly, chemical composition of cell culture substrates also appeared to affect oxygen level, with type-I collagen based cell culture systems having lower oxygen concentration compared to PDMS based cell culture systems. In general, results suggest that oxygen sensing beads can be utilized to achieve real-time and local monitoring of micro-environment oxygen level in 3D microfabricated cell culture systems.

  10. Oxygen diffusion in zircon

    NASA Astrophysics Data System (ADS)

    Watson, E. B.; Cherniak, D. J.

    1997-05-01

    Oxygen diffusion in natural, non-metamict zircon was characterized under both dry and water-present conditions at temperatures ranging from 765°C to 1500°C. Dry experiments were performed at atmospheric pressure by encapsulating polished zircon samples with a fine powder of 18O-enriched quartz and annealing the sealed capsules in air. Hydrothermal runs were conducted in cold-seal pressure vessels (7-70 MPa) or a piston cylinder apparatus (400-1000 MPa) on zircon samples encapsulated with both 18O-enriched quartz and 18O water. Diffusive-uptake profiles of 18O were measured in all samples with a particle accelerator, using the 18O(p, α) 15N reaction. For dry experimental conditions at 1100-1500°C, the resulting oxygen diffusivities (24 in all) are well described by: D dry (m 2/s) = 1.33 × 10 -4exp(-53920/T) There is no suggestion of diffusive anisotropy. Under wet conditions at 925°C, oxygen diffusion shows little or no dependence upon P H 2O in the range 7-1000 MPa, and is insensitive to total pressure as well. The results of 27 wet experiments at 767-1160°C and 7-1000 MPa can be described a single Arrhenius relationship: D wet (m 2/s) = 5.5 × 10 -12exp(-25280/T) The insensitivity of oxygen diffusion to P H 2O means that applications to geologic problems can be pursued knowing only whether the system of interest was 'wet' (i.e., P H 2O > 7MPa ) or 'dry'. Under dry conditions (presumably rare in the crust), zircons are extremely retentive of their oxygen isotopic signatures, to the extent that δ 18O would be perturbed at the center of a 200 μm zircon only during an extraordinarily hot and protracted event (e.g., 65 Ma at 900°C). Under wet conditions, δ 18O may or may not be retained in the central regions of individual crystals, cores or overgrowth rims, depending upon the specific thermal history of the system.

  11. Methods and systems for combustion dynamics reduction

    DOEpatents

    Kraemer, Gilbert Otto [Greer, SC; Varatharajan, Balachandar [Cincinnati, OH; Srinivasan, Shiva [Greer, SC; Lynch, John Joseph [Wilmington, NC; Yilmaz, Ertan [Albany, NY; Kim, Kwanwoo [Greer, SC; Lacy, Benjamin [Greer, SC; Crothers, Sarah [Greenville, SC; Singh, Kapil Kumar [Rexford, NY

    2009-08-25

    Methods and systems for combustion dynamics reduction are provided. A combustion chamber may include a first premixer and a second premixer. Each premixer may include at least one fuel injector, at least one air inlet duct, and at least one vane pack for at least partially mixing the air from the air inlet duct or ducts and fuel from the fuel injector or injectors. Each vane pack may include a plurality of fuel orifices through which at least a portion of the fuel and at least a portion of the air may pass. The vane pack or packs of the first premixer may be positioned at a first axial position and the vane pack or packs of the second premixer may be positioned at a second axial position axially staggered with respect to the first axial position.

  12. Vapor hydrogen and oxygen isotopes reflect water of combustion in the urban atmosphere

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Gorski, Galen; Strong, Courtenay; Good, Stephen P.

    Anthropogenic modification of the water cycle involves a diversity of processes, many of which have been studied intensively using models and observations. Some effective tools for measuring the contribution and fate of combustion-derived water vapor in the atmosphere are lacking, however, and this flux has received relatively little attention. We provide theoretical estimates and a first set of measurements demonstrating that water of combustion is characterized by a distinctive combination of H and O isotope ratios. Furthermore, we show that during periods of relatively low humidity and/or atmospheric stagnation, this isotopic signature can be used to quantify the concentration ofmore » water of combustion in the atmospheric boundary layer over Salt Lake City. Combustion-derived vapor concentrations vary between periods of atmospheric stratification and mixing, both on multiday and diurnal timescales, and respond over periods of hours to variations in surface emissions. Our estimates suggest that up to 13% of the boundary layer vapor during the period of study was derived from combustion sources, and both the temporal pattern and magnitude of this contribution were closely reproduced by an independent atmospheric model forced with a fossil fuel emissions data product. These findings suggest potential for water vapor isotope ratio measurements to be used in conjunction with other tracers to refine the apportionment of urban emissions, and imply that water vapor emissions associated with combustion may be a significant component of the water budget of the urban boundary layer, with potential implications for urban climate, ecohydrology, and photochemistry.« less

  13. Vapor hydrogen and oxygen isotopes reflect water of combustion in the urban atmosphere

    DOE PAGES

    Gorski, Galen; Strong, Courtenay; Good, Stephen P.; ...

    2015-03-02

    Anthropogenic modification of the water cycle involves a diversity of processes, many of which have been studied intensively using models and observations. Some effective tools for measuring the contribution and fate of combustion-derived water vapor in the atmosphere are lacking, however, and this flux has received relatively little attention. We provide theoretical estimates and a first set of measurements demonstrating that water of combustion is characterized by a distinctive combination of H and O isotope ratios. Furthermore, we show that during periods of relatively low humidity and/or atmospheric stagnation, this isotopic signature can be used to quantify the concentration ofmore » water of combustion in the atmospheric boundary layer over Salt Lake City. Combustion-derived vapor concentrations vary between periods of atmospheric stratification and mixing, both on multiday and diurnal timescales, and respond over periods of hours to variations in surface emissions. Our estimates suggest that up to 13% of the boundary layer vapor during the period of study was derived from combustion sources, and both the temporal pattern and magnitude of this contribution were closely reproduced by an independent atmospheric model forced with a fossil fuel emissions data product. These findings suggest potential for water vapor isotope ratio measurements to be used in conjunction with other tracers to refine the apportionment of urban emissions, and imply that water vapor emissions associated with combustion may be a significant component of the water budget of the urban boundary layer, with potential implications for urban climate, ecohydrology, and photochemistry.« less

  14. Vapor hydrogen and oxygen isotopes reflect water of combustion in the urban atmosphere

    PubMed Central

    Gorski, Galen; Strong, Courtenay; Good, Stephen P.; Bares, Ryan; Ehleringer, James R.; Bowen, Gabriel J.

    2015-01-01

    Anthropogenic modification of the water cycle involves a diversity of processes, many of which have been studied intensively using models and observations. Effective tools for measuring the contribution and fate of combustion-derived water vapor in the atmosphere are lacking, however, and this flux has received relatively little attention. We provide theoretical estimates and a first set of measurements demonstrating that water of combustion is characterized by a distinctive combination of H and O isotope ratios. We show that during periods of relatively low humidity and/or atmospheric stagnation, this isotopic signature can be used to quantify the concentration of water of combustion in the atmospheric boundary layer over Salt Lake City. Combustion-derived vapor concentrations vary between periods of atmospheric stratification and mixing, both on multiday and diurnal timescales, and respond over periods of hours to variations in surface emissions. Our estimates suggest that up to 13% of the boundary layer vapor during the period of study was derived from combustion sources, and both the temporal pattern and magnitude of this contribution were closely reproduced by an independent atmospheric model forced with a fossil fuel emissions data product. Our findings suggest potential for water vapor isotope ratio measurements to be used in conjunction with other tracers to refine the apportionment of urban emissions, and imply that water vapor emissions associated with combustion may be a significant component of the water budget of the urban boundary layer, with potential implications for urban climate, ecohydrology, and photochemistry. PMID:25733906

  15. Carbon deposition model for oxygen-hydrocarbon combustion. Task 6: Data analysis and formulation of an empirical model

    NASA Technical Reports Server (NTRS)

    Makel, Darby B.; Rosenberg, Sanders D.

    1990-01-01

    The formation and deposition of carbon (soot) was studied in the Carbon Deposition Model for Oxygen-Hydrocarbon Combustion Program. An empirical, 1-D model for predicting soot formation and deposition in LO2/hydrocarbon gas generators/preburners was derived. The experimental data required to anchor the model were identified and a test program to obtain the data was defined. In support of the model development, cold flow mixing experiments using a high injection density injector were performed. The purpose of this investigation was to advance the state-of-the-art in LO2/hydrocarbon gas generator design by developing a reliable engineering model of gas generator operation. The model was formulated to account for the influences of fluid dynamics, chemical kinetics, and gas generator hardware design on soot formation and deposition.

  16. Methane combustion reactivity during the metal→metallic oxide transformation of Pd-Pt catalysts: Effect of oxygen pressure

    NASA Astrophysics Data System (ADS)

    Qi, Wenjie; Ran, Jingyu; Zhang, Zhien; Niu, Juntian; Zhang, Peng; Fu, Lijuan; Hu, Bo; Li, Qilai

    2018-03-01

    Density functional theory combined with kinetic models were used to probe different kinetics consequences by which methane activation on different oxygen chemical potential surfaces as oxygen pressure increased. The metallic oxide → metal transformation temperature of Pd-Pt catalysts increased with the increase of the Pd content or/and O2 pressure. The methane conversion rate on Pt catalyst increased and then decreased to a constant value when increasing the O2 pressure, and Pd catalyst showed a poor activity performance in the case of low O2 pressure. Moreover, its activity increased as the oxygen chemical potential for O2 pressure increased in the range of 2.5-10 KPa. For metal clusters, the Csbnd H bond and Odbnd O bond activation steps occurred predominantly on *-* site pairs. The methane conversion rate was determined by O2 pressure because the adsorbed O atoms were rapidly consumed by other adsorbed species in this kinetic regime. As the O2 pressure increased, the metallic active sites for methane activation were decreased and there was no longer lack of adsorbed O atoms, resulting in the decrease of the methane conversion rate. Furthermore, when the metallic surfaces were completely covered by adsorbed oxygen atoms at higher oxygen chemical potentials, Pt catalyst showed a poor activity due to a high Csbnd H bond activation barrier on O*sbnd O*. In the case of high O2 pressure, Pd atoms preferred to segregate to the active surface of Pd-Pt catalysts, leading to the formation of PdO surfaces. The increase of Pd segregation promoted a subsequent increase in active sites and methane conversion rate. The PdO was much more active than metallic and O* saturated surfaces for methane activation, inferred from the theory and experimental study. Pd-rich bimetallic catalyst (75% molar Pd) showed a dual high methane combustion activity on O2-poor and O2-rich conditions.

  17. Reference Concepts for a Space-Based Hydrogen-Oxygen Combustion, Turboalternator, Burst Power System

    DTIC Science & Technology

    1990-07-01

    The tanks are aluminum surrounded by multifoil insulation—4 cm for hydrogen and 2 cm for oxygen. The tanks are cooled using a reverse Brayton ...Laboratory 2385 Revere Beach Parkway Everett, MA 02149 Major P. Talty HQ USAF/RD-D Washington, DC 20330-5042 Owen Taylor Westinghouse R&D

  18. The Combustion Experiment on the Sample Analysis at Mars (SAM) Instrument Suite on the Curiosity Rover

    NASA Technical Reports Server (NTRS)

    Stern, J. C.; Malespin, C. A.; Eigenbrode, J. L.; Graham, H. V.; Archer, P. D., Jr.; Brunner, A. E.; Freissinet, C.; Franz, H. B.; Fuentes, J.; Glavin, D. P.; hide

    2014-01-01

    The combustion experiment on the Sample Analysis at Mars (SAM) suite on Curiosity will heat a sample of Mars regolith in the presence of oxygen and measure composition of the evolved gases using quadrupole mass spectrometry (QMS) and tunable laser spectrometry (TLS). QMS will enable detection of combustion products such as CO, CO2, NO, and other oxidized species, while TLS will enable precise measurements of the abundance and carbon isotopic composition (delta(sup 13)C) of the evolved CO2 and hydrogen isotopic composition (deltaD) of H2O. SAM will perform a two-step combustion to isolate combustible materials below approx.550 C and above approx.550 C. The combustion experiment on SAM, if properly designed and executed, has the potential to answer multiple questions regarding the origins of volatiles seen thus far in SAM evolved gas analysis (EGA) on Mars. Constraints imposed by SAM and MSL time and power resources, as well as SAM consumables (oxygen gas), will limit the number of SAM combustion experiments, so it is imperative to design an experiment targeting the most pressing science questions. Low temperature combustion experiments will primarily target the quantification of carbon (and nitrogen) contributed by SAM wet chemistry reagants MTBSTFA (N-Methyl-N-tert-butyldimethylsilyltrifluoroacetamide) and DMF (Dimethylformamide), which have been identified in the background of blank and sample runs and may adsorb to the sample while the cup is in the Sample Manipulation System (SMS). In addition, differences between the sample and "blank" may yield information regarding abundance and delta(sup 13)C of bulk (both organic and inorganic) martian carbon. High temperature combustion experiments primarily aim to detect refractory organic matter, if present in Cumberland fines, as well as address the question of quantification and deltaD value of water evolution associated with hydroxyl hydrogen in clay minerals.

  19. Selective Enrichment of a Methanol-Utilizing Consortium Using Pulp and Paper Mill Waste Streams

    NASA Astrophysics Data System (ADS)

    Mockos, Gregory R.; Smith, William A.; Loge, Frank J.; Thompson, David N.

    Efficient utilization of carbon inputs is critical to the economic viability of the current forest products sector. Input carbon losses occur in various locations within a pulp mill, including losses as volatile organics and wastewater. Opportunities exist to capture this carbon in the form of value-added products such as biodegradable polymers. Wasteactivated sludge from a pulp mill wastewater facility was enriched for 80 days for a methanol-utilizing consortium with the goal of using this consortium to produce biopolymers from methanol-rich pulp mill waste streams. Five enrichment conditions were utilized: three high-methanol streams from the kraft mill foul condensate system, one methanol-amended stream from the mill wastewater plant, and one methanol-only enrichment. Enrichment reactors were operated aerobically in sequencing batch mode at neutral pH and 25°C with a hydraulic residence time and a solids retention time of 4 days. Non-enriched waste activated sludge did not consume methanol or reduce chemical oxygen demand. With enrichment, however, the chemical oxygen demand reduction over 24-h feed/ decant cycles ranged from 79 to 89%, and methanol concentrations dropped below method detection limits. Neither the non-enriched waste-activated sludge nor any of the enrichment cultures accumulated polyhydroxyalkanoates (PHAs) under conditions of nitrogen sufficiency. Similarly, the non-enriched waste activated sludge did not accumulate PHAs under nitrogen-limited conditions. By contrast, enriched cultures accumulated PHAs to nearly 14% on a dry weight basis under nitrogen-limited conditions. This indicates that selectively enriched pulp mill waste activated sludge can serve as an inoculum for PHA production from methanol-rich pulp mill effluents.

  20. Cascade heat recovery with coproduct gas production

    DOEpatents

    Brown, William R.; Cassano, Anthony A.; Dunbobbin, Brian R.; Rao, Pradip; Erickson, Donald C.

    1986-01-01

    A process for the integration of a chemical absorption separation of oxygen and nitrogen from air with a combustion process is set forth wherein excess temperature availability from the combustion process is more effectively utilized to desorb oxygen product from the absorbent and then the sensible heat and absorption reaction heat is further utilized to produce a high temperature process stream. The oxygen may be utilized to enrich the combustion process wherein the high temperature heat for desorption is conducted in a heat exchange preferably performed with a pressure differential of less than 10 atmospheres which provides considerable flexibility in the heat exchange.

  1. Chemical composition and properties of ashes from combustion plants using Miscanthus as fuel.

    PubMed

    Lanzerstorfer, Christof

    2017-04-01

    Miscanthus giganteus is one of the energy crops considered to show potential for a substantial contribution to sustainable energy production. In the literature there is little data available about the chemical composition of ashes from the combustion of Miscanthus and practically no data about their physical properties. However, for handling, treatment and utilization of the ashes this information is important. In this study ashes from two biomass combustion plants using Miscanthus as fuel were investigated. The density of the ashes was 2230±35kg/m 3 , which was similar to the density of ashes from straw combustion. Also the bulk densities were close to those reported for straw ashes. The flowability of the ashes was a little worse than the flowability of ashes from wood combustion. The measured heavy metal concentrations were below the usual limits for utilization of the ashes as soil conditioner. The concentrations in the bottom ash were similar to those reported for ash from forest residue combustion plants. In comparison with cyclone fly ashes from forest residue combustion the measured heavy metal concentrations in the cyclone fly ash were considerably lower. Cl - , S and Zn were enriched in the cyclone fly ash which is also known for ashes from wood combustion. In comparison with literature data obtained from Miscanthus plant material the concentrations of K, Cl - and S were lower. This can be attributed to the fact that the finest fly ash is not collected by the cyclone de-dusting system of the Miscanthus combustion plants. Copyright © 2016. Published by Elsevier B.V.

  2. Systems and methods of storing combustion waste products

    DOEpatents

    Chen, Shen-En; Wang, Peng; Miao, Xiexing; Feng, Qiyan; Zhu, Qianlin

    2016-04-12

    In one aspect, methods of storing one or more combustion waste products are described herein. Combustion waste products stored by a method described herein can include solid combustion waste products such as coal ash and/or gaseous combustion products such as carbon dioxide. In some embodiments, a method of storing carbon dioxide comprises providing a carbon dioxide storage medium comprising porous concrete having a macroporous and microporous pore structure and flowing carbon dioxide captured from a combustion flue gas source into the pore structure of the porous concrete.

  3. 14 CFR 23.1445 - Oxygen distribution system.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Oxygen distribution system. 23.1445 Section... Equipment § 23.1445 Oxygen distribution system. Link to an amendment published at 76 FR 75762, December 2, 2011. (a) Except for flexible lines from oxygen outlets to the dispensing units, or where shown to be...

  4. [Catalytic performance of Ce/Zr series catalysts on soot combustion].

    PubMed

    Zhu, Ling; Wang, Xue-Zhong; Hao, Zheng-Ping

    2005-09-01

    Catalytic performances of Ce/Zr series catalysts (Ce(x)Zr(1-x)O2) on soot combustion and the influence of feed gas were investigated by TG and TPO. The catalytic activity is high, and affects by the Ce/Zr ratio. The concentration of O2 affects the speed-limited step during the process of soot combustion. H2O showed no effect on the catalytic activity for soot combustion on Ce(0.5)Zr(0.5)O2. NO could promote soot combustion by presenting NO2, a more powerful oxidant than O2, and the ignition temperature of soot decreased 30 degrees C. Results of TG and TPO show that the beta species oxygen on the catalyst take part in the combustion process.

  5. Combustion of solid carbon rods in zero and normal gravity

    NASA Technical Reports Server (NTRS)

    Spuckler, C. M.; Kohl, F. J.; Miller, R. A.; Stearns, C. A.; Dewitt, K. J.

    1979-01-01

    In order to investigate the mechanism of carbon combustion, spectroscopic carbon rods were resistance ignited and burned in an oxygen environment in normal and zero gravity. Direct mass spectrometric sampling was used in the normal gravity tests to obtain concentration profiles of CO2, CO, and O2 as a function of distance from the carbon surface. The experimental concentrations were compared to those predicted by a stagnant film model. Zero gravity droptower tests were conducted in order to assess the effect of convection on the normal gravity combustion process. The ratio of flame diameter to rod diameter as a function of time for oxygen pressures of 5, 10, 15, and 20 psia was obtained for three different diameter rods. It was found that this ratio was inversely proportional to both the oxygen pressure and the rod diameter.

  6. Extraterrestrial surface propulsion systems

    NASA Astrophysics Data System (ADS)

    Ash, Robert L.; Blackstock, Dexter L.; Barnhouse, K.; Charalambous, Z.; Coats, J.; Danagan, J.; Davis, T.; Dickens, J.; Harris, P.; Horner, G.

    Lunar traction systems, Mars oxygen production, and Mars methane engine operation were the three topics studied during 1992. An elastic loop track system for lunar construction operations was redesigned and is being tested. A great deal of work on simulating the lunar environment to facilitate traction testing has been reported. Operation of an oxygen processor under vacuum conditions has been the focus of another design team. They have redesigned the processor facility. This included improved seals and heat shields. Assuming methane and oxygen can be produced from surface resources on Mars, a third design team has addressed the problem of using Mars atmospheric carbon dioxide to control combustion temperatures in an internal combustion engine. That team has identified appropriate tests and instrumentation. They have reported on the test rig that they designed and the computer-based system for acquiring data.

  7. Extraterrestrial surface propulsion systems

    NASA Technical Reports Server (NTRS)

    Ash, Robert L.; Blackstock, Dexter L.; Barnhouse, K.; Charalambous, Z.; Coats, J.; Danagan, J.; Davis, T.; Dickens, J.; Harris, P.; Horner, G.

    1992-01-01

    Lunar traction systems, Mars oxygen production, and Mars methane engine operation were the three topics studied during 1992. An elastic loop track system for lunar construction operations was redesigned and is being tested. A great deal of work on simulating the lunar environment to facilitate traction testing has been reported. Operation of an oxygen processor under vacuum conditions has been the focus of another design team. They have redesigned the processor facility. This included improved seals and heat shields. Assuming methane and oxygen can be produced from surface resources on Mars, a third design team has addressed the problem of using Mars atmospheric carbon dioxide to control combustion temperatures in an internal combustion engine. That team has identified appropriate tests and instrumentation. They have reported on the test rig that they designed and the computer-based system for acquiring data.

  8. Monopropellant combustion system

    NASA Technical Reports Server (NTRS)

    Berg, Gerald R. (Inventor); Mueller, Donn C. (Inventor); Parish, Mark W. (Inventor)

    2005-01-01

    An apparatus and method are provided for decomposition of a propellant. The propellant includes an ionic salt and an additional fuel. Means are provided for decomposing a major portion of the ionic salt. Means are provided for combusting the additional fuel and decomposition products of the ionic salt.

  9. Turbulence in a gaseous hydrogen-liquid oxygen rocket combustion chamber

    NASA Technical Reports Server (NTRS)

    Lebas, J.; Tou, P.; Ohara, J.

    1975-01-01

    The intensity of turbulence and the Lagrangian correlation coefficient for a LOX-GH2 rocket combustion chamber was determined from experimental measurements of tracer gas diffusion. A combination of Taylor's turbulent diffusion theory and a numerical method for solving the conservation equations of fluid mechanics was used to calculate these quantities. Taylor's theory was extended to consider the inhomogeneity of the turbulence field in the axial direction of the combustion chamber, and an exponential function was used to represent the Lagrangian correlation coefficient. The results indicate that the value of the intensity of turbulence reaches a maximum of 14% at a location about 7" downstream from the injector. The Lagrangian correlation coefficient associated with this value is given by the above exponential expression where alpha = 10,000/sec.

  10. Smoldering Combustion Experiments in Microgravity

    NASA Technical Reports Server (NTRS)

    Walther, David C.; Fernandez-Pello, A. Carlos; Urban, David L.

    1997-01-01

    The Microgravity Smoldering Combustion (MSC) experiment is part of a study of the smolder characteristics of porous combustible materials in a microgravity environment. Smoldering is a non-flaming form of combustion that takes place in the interior of porous materials and takes place in a number of processes ranging from smoldering of porous insulation materials to high temperature synthesis of metals. The objective of the study is to provide a better understanding of the controlling mechanisms of smolder, both in microgravity and normal-gravity. As with many forms of combustion, gravity affects the availability of oxidizer and transport of heat, and therefore the rate of combustion. Microgravity smolder experiments, in both a quiescent oxidizing environment, and in a forced oxidizing flow have been conducted aboard the NASA Space Shuttle (STS-69 and STS-77 missions) to determine the effect of the ambient oxygen concentration and oxidizer forced flow velocity on smolder combustion in microgravity. The experimental apparatus is contained within the NASA Get Away Special Canister (GAS-CAN) Payload. These two sets of experiments investigate the propagation of smolder along the polyurethane foam sample under both diffusion driven and forced flow driven smoldering. The results of the microgravity experiments are compared with identical ones carried out in normal gravity, and are used to verify present theories of smolder combustion. The results of this study will provide new insights into the smoldering combustion process. Thermocouple histories show that the microgravity smolder reaction temperatures (Ts) and propagation velocities (Us) lie between those of identical normal-gravity upward and downward tests. These observations indicate the effect of buoyancy on the transport of oxidizer to the reaction front.

  11. A sustained-arc ignition system for internal combustion engines

    NASA Technical Reports Server (NTRS)

    Birchenough, A. G.

    1977-01-01

    A sustained-arc ignition system was developed for internal combustion engines. It produces a very-long-duration ignition pulse with an energy in the order of 100 millijoules. The ignition pulse waveform can be controlled to predetermined actual ignition requirements. The design of the sustained-arc ignition system is presented in the report.

  12. Dust-bathing behavior of laying hens in enriched colony housing systems and an aviary system

    PubMed Central

    Louton, H.; Bergmann, S.; Reese, S.; Erhard, M. H.; Rauch, E.

    2016-01-01

    The dust-bathing behavior of Lohmann Selected Leghorn hens was compared in 4 enriched colony housing systems and in an aviary system. The enriched colony housing systems differed especially in the alignment and division of the functional areas dust bath, nest, and perches. Forty-eight-hour video recordings were performed at 3 time-points during the laying period, and focal animal sampling and behavior sampling methods were used to analyze the dust-bathing behavior. Focal animal data included the relative fractions of dust-bathing hens overall, of hens bathing in the dust-bath area, and of those bathing on the wire floor throughout the day. Behavior data included the number of dust-bathing bouts within a predefined time range, the duration of 1 bout, the number of and reasons for interruptions, and the number of and reasons for the termination of dust-bathing bouts. Results showed that the average duration of dust bathing varied between the 4 enriched colony housing systems compared with the aviary system. The duration of dust-bathing bouts was shorter than reported under natural conditions. A positive correlation between dust-bathing activity and size of the dust-bath area was observed. Frequently, dust baths were interrupted and terminated by disturbing influences such as pecking by other hens. This was especially observed in the enriched colony housing systems. In none of the observed systems, neither in the enriched colony housing nor in the aviary system, were all of the observed dust baths terminated “normally.” Dust bathing behavior on the wire mesh rather than in the provided dust-bath area generally was observed at different frequencies in all enriched colony housing systems during all observation periods, but never in the aviary system. The size and design of the dust-bath area influenced the prevalence of dust-bathing behavior in that small and subdivided dust-bath areas reduced the number of dust-bathing bouts but increased the incidence of sham dust

  13. Study on the laser irradiation characteristics of NEPE propellant in different oxygen concentrations

    NASA Astrophysics Data System (ADS)

    Xiang, Hengsheng; Chen, Xiong; Zhou, Changsheng

    2016-01-01

    The ignition and combustion characteristics of nitrate ester plasticized polyether (NEPE) propellant in different oxygen concentrations ambient gases were studied by the application of CO2 laser, infrared thermometer and high speed camera. The flame intensity data of the propellant was collected by the photodiode; propellant flame temperature was measured by infrared thermometer. The experimental results show that the time which NEPE propellant spend to be stable combustion will get shorter with the increase of oxygen concentration; the flame peak temperature measured by infrared thermometer increases with the increase of oxygen concentration when the oxygen concentration is less than 30% by volume, then decreases with the increase of oxygen concentration.

  14. Oxygen index evaluation of fire-retardant-treated wood

    Treesearch

    Robert H. White

    1979-01-01

    The applicability of using the oxygen index test (ASTM D 2863-76) to obtain an indication of the relative flammability of fire-retardant- treated wood products was investigated. The oxygen index is the minimum percentage oxygen that is required to maintain flaming combustion of a specimen under specified laboratory conditions. Within the plastics industry, the test is...

  15. Flammability of Heterogeneously Combusting Metals

    NASA Technical Reports Server (NTRS)

    Jones, Peter D.

    1998-01-01

    Most engineering materials, including some metals, most notably aluminum, burn in homogeneous combustion. 'Homogeneous' refers to both the fuel and the oxidizer being in the same phase, which is usually gaseous. The fuel and oxidizer are well mixed in the combustion reaction zone, and heat is released according to some relation like q(sub c) = delta H(sub c)c[((rho/rho(sub 0))]exp a)(exp -E(sub c)/RT), Eq. (1) where the pressure exponent a is usually close to unity. As long as there is enough heat released, combustion is sustained. It is useful to conceive of a threshold pressure beyond which there is sufficient heat to keep the temperature high enough to sustain combustion, and beneath which the heat is so low that temperature drains away and the combustion is extinguished. Some materials burn in heterogeneous combustion, in which the fuel and oxidizer are in different phases. These include iron and nickel based alloys, which burn in the liquid phase with gaseous oxygen. Heterogeneous combustion takes place on the surface of the material (fuel). Products of combustion may appear as a solid slag (oxide) which progressively covers the fuel. Propagation of the combustion melts and exposes fresh fuel. Heterogeneous combustion heat release also follows the general form of Eq.(1), except that the pressure exponent a tends to be much less than 1. Therefore, the increase in heat release with increasing pressure is not as dramatic as it is in homogeneous combustion. Although the concept of a threshold pressure still holds in heterogeneous combustion, the threshold is more difficult to identify experimentally, and pressure itself becomes less important relative to the heat transfer paths extant in any specific application. However, the constants C, a, and E(sub c) may still be identified by suitable data reduction from heterogeneous combustion experiments, and may be applied in a heat transfer model to judge the flammability of a material in any particular actual

  16. New potentials for conventional aircraft when powered by hydrogen-enriched gasoline

    NASA Technical Reports Server (NTRS)

    Menard, W. A.; Moynihan, P. I.; Rupe, J. H.

    1976-01-01

    Overall system efficiency and performance of a Beech Model 20 Duke aircraft was studied to provide analytical representations of an aircraft piston engine system, including all essential components required for onboard hydrogen generation. Lower emission levels and a 20% reduction in fuel consumption may be obtained by using a catalytic hydrogen generator, incorporated as part of the air induction system, to generate hydrogen by breaking down small amounts of the aviation gasoline used in the normal propulsion system. This hydrogen is then mixed with gasoline and compressed air from the turbocharger before entering the engine combustion chamber. The special properties of the hydrogen-enriched gasoline allow the engine to operate at ultra lean fuel/air ratios, resulting in higher efficiencies.

  17. Co-firing coal and biomass blends and their influence on the post-combustion CO2 capture installation

    NASA Astrophysics Data System (ADS)

    Więckol-Ryk, Angelika; Smoliński, Adam

    2017-10-01

    Co-firing of biomass with coal for energy production is a well-known technology and plays an important role in the electricity sector. The post-combustion capture integrated with biomass-fired power plants (Bio-CCS) seems to be a new alternative for reducing greenhouse gas emissions. This study refers to the best known and advanced technology for post-combustion CO2 capture (PCC) based on a chemical absorption in monoethanolamine (MEA). The co-firing of hard coal with four types of biomass was investigated using a laboratory fixed bed reactor system. The comparison of gaseous products emitted from the combustion of coal and different biomass blends were determined using gas chromatography. Research proved that co-firing of biomass in fossil fuel power plants is beneficial for PCC process. It may also reduce the corrosion of CO2 capture installation. The oxygen concentration in the flue gases from hard coal combustion was comparable with the respective value for a fuel blend of biomass content of 20% w/w. It was also noted that an increase in biomass content in a sample from 20 to 40 % w/w increased the concentration of oxygen in the flue gas streams. However, this concentration should not have a significant impact on the rate of amine oxidative degradation.

  18. Internal and Surface Phenomena in Heterogenous Metal Combustion

    NASA Technical Reports Server (NTRS)

    Dreizin, Edward L.

    1997-01-01

    The phenomenon of gas dissolution in burning metals was observed in recent metal combustion studies, but it could not be adequately explained by the traditional metal combustion models. The research reported here addresses heterogeneous metal combustion with emphasis on the processes of oxygen penetration inside burning metal and its influence on the metal combustion rate, temperature history, and disruptive burning. The unique feature of this work is the combination of the microgravity environment with a novel micro-arc generator of monodispersed metal droplets, ensuring repeatable formation and ignition of uniform metal droplets with a controllable initial temperature and velocity. Burning droplet temperature is measured in real time with a three wavelength pyrometer. In addition, particles are rapidly quenched at different combustion times, cross-sectioned, and examined using SEM-based techniques to retrieve the internal composition history of burning metal particles. When the initial velocity of a spherical particle is nearly zero, the microgravity environment makes it possible to study the flame structure, the development of flame nonsymmetry, and correlation of the flame shape with the heterogeneous combustion processes.

  19. Technique for in-place welding of aluminum backed up by a combustible material

    NASA Technical Reports Server (NTRS)

    Spagnuolo, A. C.

    1971-01-01

    Welding external aluminum jacket, tightly wrapped around inner layer of wood composition fiberboard, in oxygen free environment prevents combustion and subsequent damage to underlying fiberboard. Technique also applies to metal cutting in similar assemblies without disassembly to remove combustible materials from welding heat proximity.

  20. Improved wound management by regulated negative pressure-assisted wound therapy and regulated, oxygen- enriched negative pressure-assisted wound therapy through basic science research and clinical assessment.

    PubMed

    Topaz, Moris

    2012-05-01

    Regulated negative pressure-assisted wound therapy (RNPT) should be regarded as a state-of-the-art technology in wound treatment and the most important physical, nonpharmaceutical, platform technology developed and applied for wound healing in the last two decades. RNPT systems maintain the treated wound's environment as a semi-closed, semi-isolated system applying external physical stimulations to the wound, leading to biological and biochemical effects, with the potential to substantially influence wound-host interactions, and when properly applied may enhance wound healing. RNPT is a simple, safe, and affordable tool that can be utilized in a wide range of acute and chronic conditions, with reduced need for complicated surgical procedures, and antibiotic treatment. This technology has been shown to be effective and safe, saving limbs and lives on a global scale. Regulated, oxygen-enriched negative pressure-assisted wound therapy (RO-NPT) is an innovative technology, whereby supplemental oxygen is concurrently administered with RNPT for their synergistic effect on treatment and prophylaxis of anaerobic wound infection and promotion of wound healing. Understanding the basic science, modes of operation and the associated risks of these technologies through their fundamental clinical mechanisms is the main objective of this review.

  1. Progress towards an Optimization Methodology for Combustion-Driven Portable Thermoelectric Power Generation Systems

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Krishnan, Shankar; Karri, Naveen K.; Gogna, Pawan K.

    2012-03-13

    Enormous military and commercial interests exist in developing quiet, lightweight, and compact thermoelectric (TE) power generation systems. This paper investigates design integration and analysis of an advanced TE power generation system implementing JP-8 fueled combustion and thermal recuperation. Design and development of a portable TE power system using a JP-8 combustor as a high temperature heat source and optimal process flows depend on efficient heat generation, transfer, and recovery within the system are explored. Design optimization of the system required considering the combustion system efficiency and TE conversion efficiency simultaneously. The combustor performance and TE sub-system performance were coupled directlymore » through exhaust temperatures, fuel and air mass flow rates, heat exchanger performance, subsequent hot-side temperatures, and cold-side cooling techniques and temperatures. Systematic investigation of this system relied on accurate thermodynamic modeling of complex, high-temperature combustion processes concomitantly with detailed thermoelectric converter thermal/mechanical modeling. To this end, this work reports on design integration of systemlevel process flow simulations using commercial software CHEMCADTM with in-house thermoelectric converter and module optimization, and heat exchanger analyses using COMSOLTM software. High-performance, high-temperature TE materials and segmented TE element designs are incorporated in coupled design analyses to achieve predicted TE subsystem level conversion efficiencies exceeding 10%. These TE advances are integrated with a high performance microtechnology combustion reactor based on recent advances at the Pacific Northwest National Laboratory (PNNL). Predictions from this coupled simulation established a basis for optimal selection of fuel and air flow rates, thermoelectric module design and operating conditions, and microtechnology heat-exchanger design criteria. This paper will discuss

  2. Flame Suppression Agent, System and Uses

    NASA Technical Reports Server (NTRS)

    Parrish, Clyde F. (Inventor)

    2013-01-01

    Aqueous droplets encapsulated in a flame retardant polymer are useful in suppressing combustion. Upon exposure to a flame, the encapsulated aqueous droplets rupture and vaporize, removing heat and displacing oxygen to retard the combustion process. The polymer encapsulant, through decomposition, may further add free radicals to the combustion atmosphere, thereby further retarding the combustion process. The encapsulated aqueous droplets may be used as a replacement to halon, water mist and dry powder flame suppression systems.

  3. Low energy consumption method for separating gaseous mixtures and in particular for medium purity oxygen production

    DOEpatents

    Jujasz, Albert J.; Burkhart, James A.; Greenberg, Ralph

    1988-01-01

    A method for the separation of gaseous mixtures such as air and for producing medium purity oxygen, comprising compressing the gaseous mixture in a first compressor to about 3.9-4.1 atmospheres pressure, passing said compressed gaseous mixture in heat exchange relationship with sub-ambient temperature gaseous nitrogen, dividing the cooled, pressurized gaseous mixture into first and second streams, introducing the first stream into the high pressure chamber of a double rectification column, separating the gaseous mixture in the rectification column into a liquid oxygen-enriched stream and a gaseous nitrogen stream and supplying the gaseous nitrogen stream for cooling the compressed gaseous mixture, removing the liquid oxygen-enriched stream from the low pressure chamber of the rectification column and pumping the liquid, oxygen-enriched steam to a predetermined pressure, cooling the second stream, condensing the cooled second stream and evaporating the oxygen-enriched stream in an evaporator-condenser, delivering the condensed second stream to the high pressure chamber of the rectification column, and heating the oxygen-enriched stream and blending the oxygen-enriched stream with a compressed blend-air stream to the desired oxygen concentration.

  4. Laser systems for the combustion research facility - Diana

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Miller, C.K.; Lavasek, J.W.; Jones, E.D.

    1982-03-01

    A 5-Joule/pulse, 1.8-..mu..s-pulse-width, 10-ppS flashlamp-pumped tunable-dye-laser system, called Diana, has been built for use in experiments to be performed at the Combustion Research Facility, Sandia National Laboratories, Livermore. Design specifications for the system and details of construction are described, and it is noted that performance of the laser meets or exceeds all design criteria. Areas for further performance improvements are discussed, and updates are suggested to enhance system usefulness.

  5. Constant-Pressure Combustion Charts Including Effects of Diluent Addition

    NASA Technical Reports Server (NTRS)

    Turner, L Richard; Bogart, Donald

    1949-01-01

    Charts are presented for the calculation of (a) the final temperatures and the temperature changes involved in constant-pressure combustion processes of air and in products of combustion of air and hydrocarbon fuels, and (b) the quantity of hydrocarbon fuels required in order to attain a specified combustion temperature when water, alcohol, water-alcohol mixtures, liquid ammonia, liquid carbon dioxide, liquid nitrogen, liquid oxygen, or their mixtures are added to air as diluents or refrigerants. The ideal combustion process and combustion with incomplete heat release from the primary fuel and from combustible diluents are considered. The effect of preheating the mixture of air and diluents and the effect of an initial water-vapor content in the combustion air on the required fuel quantity are also included. The charts are applicable only to processes in which the final mixture is leaner than stoichiometric and at temperatures where dissociation is unimportant. A chart is also included to permit the calculation of the stoichiometric ratio of hydrocarbon fuel to air with diluent addition. The use of the charts is illustrated by numerical examples.

  6. Highly Turbulent Counterflow Flames: A Laboratory Scale Benchmark for Practical Combustion Systems

    NASA Astrophysics Data System (ADS)

    Gomez, Alessandro

    2013-11-01

    Since the pioneering work of Weinberg's group at Imperial College in the `60s, the counterflow system has been the workhorse of laminar flame studies. Recent developments have shown that it is also a promising benchmark for highly turbulent (Ret ~ 1000) nonpremixed and premixed flames of direct relevance to gasturbine combustion. Case studies will demonstrate the versatility of the system in mimicking real flame effects, such as heat loss and flame stratification in premixed flames, and the compactness of the combustion region. The system may offer significant advantages from a computational viewpoint, including: a) aerodynamic flame stabilization near the interface between the two opposed jets, with ensuing simplifications in the prescription of boundary conditions; b) a fiftyfold reduction of the domain of interest as compared to conventional nonpremixed jet flames at the same Reynolds number; and c) millisecond mean residence times, which is particularly useful for DNS/LES computational modeling, and for soot suppression in the combustion of practical fuels.

  7. Evaluation of char combustion models: measurement and analysis of variability in char particle size and density

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Maloney, Daniel J; Monazam, Esmail R; Casleton, Kent H

    Char samples representing a range of combustion conditions and extents of burnout were obtained from a well-characterized laminar flow combustion experiment. Individual particles from the parent coal and char samples were characterized to determine distributions in particle volume, mass, and density at different extent of burnout. The data were then compared with predictions from a comprehensive char combustion model referred to as the char burnout kinetics model (CBK). The data clearly reflect the particle- to-particle heterogeneity of the parent coal and show a significant broadening in the size and density distributions of the chars resulting from both devolatilization and combustion.more » Data for chars prepared in a lower oxygen content environment (6% oxygen by vol.) are consistent with zone II type combustion behavior where most of the combustion is occurring near the particle surface. At higher oxygen contents (12% by vol.), the data show indications of more burning occurring in the particle interior. The CBK model does a good job of predicting the general nature of the development of size and density distributions during burning but the input distribution of particle size and density is critical to obtaining good predictions. A significant reduction in particle size was observed to occur as a result of devolatilization. For comprehensive combustion models to provide accurate predictions, this size reduction phenomenon needs to be included in devolatilization models so that representative char distributions are carried through the calculations.« less

  8. Enrichment Assay Methods Development for the Integrated Cylinder Verification System

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Smith, Leon E.; Misner, Alex C.; Hatchell, Brian K.

    2009-10-22

    International Atomic Energy Agency (IAEA) inspectors currently perform periodic inspections at uranium enrichment plants to verify UF6 cylinder enrichment declarations. Measurements are typically performed with handheld high-resolution sensors on a sampling of cylinders taken to be representative of the facility's entire product-cylinder inventory. Pacific Northwest National Laboratory (PNNL) is developing a concept to automate the verification of enrichment plant cylinders to enable 100 percent product-cylinder verification and potentially, mass-balance calculations on the facility as a whole (by also measuring feed and tails cylinders). The Integrated Cylinder Verification System (ICVS) could be located at key measurement points to positively identify eachmore » cylinder, measure its mass and enrichment, store the collected data in a secure database, and maintain continuity of knowledge on measured cylinders until IAEA inspector arrival. The three main objectives of this FY09 project are summarized here and described in more detail in the report: (1) Develop a preliminary design for a prototype NDA system, (2) Refine PNNL's MCNP models of the NDA system, and (3) Procure and test key pulse-processing components. Progress against these tasks to date, and next steps, are discussed.« less

  9. Particulate matter emissions, and metals and toxic elements in airborne particulates emitted from biomass combustion: The importance of biomass type and combustion conditions.

    PubMed

    Zosima, Angela T; Tsakanika, Lamprini-Areti V; Ochsenkühn-Petropoulou, Maria Th

    2017-05-12

    The aim of this study was to investigate the impact of biomass combustion with respect to burning conditions and fuel types on particulate matter emissions (PM 10 ) and their metals as well as toxic elements content. For this purpose, different lab scale burning conditions were tested (20 and 13% O 2 in the exhaust gas which simulate an incomplete and complete combustion respectively). Furthermore, two pellet stoves (8.5 and 10 kW) and one open fireplace were also tested. In all cases, 8 fuel types of biomass produced in Greece were used. Average PM 10 emissions ranged at laboratory-scale combustions from about 65 to 170 mg/m 3 with flow oxygen at 13% in the exhaust gas and from 85 to 220 mg/m 3 at 20% O 2 . At pellet stoves the emissions were found lower (35 -85 mg/m 3 ) than the open fireplace (105-195 mg/m 3 ). The maximum permitted particle emission limit is 150 mg/m 3 . Metals on the PM 10 filters were determined by several spectrometric techniques after appropriate digestion or acid leaching of the filters, and the results obtained by these two methods were compared. The concentration of PM 10 as well as the total concentration of the metals on the filters after the digestion procedure appeared higher at laboratory-scale combustions with flow oxygen at 20% in the exhaust gas and even higher at fireplace in comparison to laboratory-scale combustions with 13% O 2 and pellet stoves. Modern combustion appliances and appropriate types of biomass emit lower PM 10 emissions and lower concentration of metals than the traditional devices where incomplete combustion conditions are observed. Finally, a comparison with other studies was conducted resulting in similar results.

  10. Production and application of O2 enriched air produced by fresh and salt water desorption in chemical plants.

    PubMed

    Galli, F; Previtali, D; Bozzano, G; Bianchi, C L; Manenti, F; Pirola, C

    2018-07-01

    Oxygen enriched air intensifies oxidation processes since smaller reactors reach the same conversion of typical unit operations that employ simple air as reactant. However, the cost to produce pure oxygen or oxygen enriched air with traditional methods, i.e. cryogenic separation or membrane technologies, may be unaffordable. Here, we propose a new continuous technology for gas mixture separation, focusing on the production of oxygen enriched air as a case study. This operation is an absorption-desorption process that takes advantage of the higher oxygen solubility in water compared to nitrogen. In a pressurized solubilisation tank, water absorbs air. Subsequently, reducing pressure desorbs oxygen enriched air. PRO/II 9.3 (Simsci-Scheider Electrics) simulated, optimized, and calculated the capital and operative expenses of this technology. Moreover, we tested for the first time salt water instead of distilled water as appealing possibility for chemical plant near sea and ocean. We varied the inlet water flowrate between 5 and 15 m 3 /h. The optimum operative absortion unit pressure is 15-35 barg. After degassing, water may be recycled. With salt water, the extracted quantity of enriched air decreases compared with the desorption from fresh water (20% less), while the concentration of oxygen is independent from the salt concentration. The cost of enriched air at the optimum condition is 2-3.35 EUR/Nm 3 . Copyright © 2018 Elsevier Ltd. All rights reserved.

  11. An Experimental Study of Unconfined Hydrogen/Oxygen and Hydrogen/Air Explosions

    NASA Technical Reports Server (NTRS)

    Richardson, Erin; Skinner, Troy; Blackwood, James; Hays, Michael; Bangham, Mike; Jackson, Austin

    2014-01-01

    Development tests are being conducted to characterize unconfined Hydrogen/air and Hydrogen/Oxygen blast characteristics. Most of the existing experiments for these types of explosions address contained explosions, like shock tubes. Therefore, the Hydrogen Unconfined Combustion Test Apparatus (HUCTA) has been developed as a gaseous combustion test device for determining the relationship between overpressure, impulse, and flame speed at various mixture ratios for unconfined reactions of hydrogen/oxygen and hydrogen/air. The system consists of a central platform plumbed to inject and mix component gasses into an attached translucent bag or balloon while monitoring hydrogen concentration. All tests are ignited with a spark with plans to introduce higher energy ignition sources in the future. Surrounding the platform are 9 blast pressure "Pencil" probes. Two high-speed cameras are used to observe flame speed within the combustion zone. The entire system is raised approx. 6 feet off the ground to remove any ground reflection from the measurements. As of this writing greater than 175 tests have been performed and include Design of Experiments test sets. Many of these early tests have used bags or balloons between approx. 340L and approx. 1850L to quantify the effect of gaseous mixture ratio on the properties of interest. All data acquisition is synchronized between the high-speed cameras, the probes, and the ignition system to observe flame and shock propagation. Successful attempts have been made to couple the pressure profile with the progress of the flame front within the combustion zone by placing a probe within the bag. Overpressure and impulse data obtained from these tests are used to anchor engineering analysis tools, CFD models and in the development of blast and fragment acceleration models.

  12. The READY program: Building a global potential energy surface and reactive dynamic simulations for the hydrogen combustion.

    PubMed

    Mogo, César; Brandão, João

    2014-06-30

    READY (REActive DYnamics) is a program for studying reactive dynamic systems using a global potential energy surface (PES) built from previously existing PESs corresponding to each of the most important elementary reactions present in the system. We present an application to the combustion dynamics of a mixture of hydrogen and oxygen using accurate PESs for all the systems involving up to four oxygen and hydrogen atoms. Results at the temperature of 4000 K and pressure of 2 atm are presented and compared with model based on rate constants. Drawbacks and advantages of this approach are discussed and future directions of research are pointed out. Copyright © 2014 Wiley Periodicals, Inc.

  13. Final Technical Report: Vibrational Spectroscopy of Transient Combustion Intermediates Trapped in Helium Nanodroplets

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Douberly, Gary Elliott

    The objective of our experimental research program is to isolate and stabilize transient intermediates and products of prototype combustion reactions. This will be accomplished by Helium Nanodroplet Isolation, a novel technique where liquid helium droplets freeze out high energy metastable configurations of a reacting system, permitting infrared spectroscopic characterizations of products and intermediates that result from hydrocarbon radical reactions with molecular oxygen and other small molecules relevant to combustion environments. The low temperature (0.4 K) and rapid cooling associated with He droplets provides a perfectly suited medium to isolate and probe a broad range of molecular radical and carbene systemsmore » important to combustion chemistry. The sequential addition of molecular species to He droplets often leads to the stabilization of high-energy, metastable cluster configurations that represent regions of the potential energy surface far from the global minimum. Single and double resonance IR laser spectroscopy techniques, along with Stark and Zeeman capabilities, are being used to probe the structural and dynamical properties of these systems.« less

  14. Compression ignition engine having fuel system for non-sooting combustion and method

    DOEpatents

    Bazyn, Timothy; Gehrke, Christopher

    2014-10-28

    A direct injection compression ignition internal combustion engine includes a fuel system having a nozzle extending into a cylinder of the engine and a plurality of spray orifices formed in the nozzle. Each of the spray orifices has an inner diameter dimension of about 0.09 mm or less, and define inter-orifice angles between adjacent spray orifice center axes of about 36.degree. or greater such that spray plumes of injected fuel from each of the spray orifices combust within the cylinder according to a non-sooting lifted flame and gas entrainment combustion pattern. Related methodology is also disclosed.

  15. Supercomputer modeling of hydrogen combustion in rocket engines

    NASA Astrophysics Data System (ADS)

    Betelin, V. B.; Nikitin, V. F.; Altukhov, D. I.; Dushin, V. R.; Koo, Jaye

    2013-08-01

    Hydrogen being an ecological fuel is very attractive now for rocket engines designers. However, peculiarities of hydrogen combustion kinetics, the presence of zones of inverse dependence of reaction rate on pressure, etc. prevents from using hydrogen engines in all stages not being supported by other types of engines, which often brings the ecological gains back to zero from using hydrogen. Computer aided design of new effective and clean hydrogen engines needs mathematical tools for supercomputer modeling of hydrogen-oxygen components mixing and combustion in rocket engines. The paper presents the results of developing verification and validation of mathematical model making it possible to simulate unsteady processes of ignition and combustion in rocket engines.

  16. Safety Standard for Oxygen and Oxygen Systems: Guidelines for Oxygen System Design, Materials Selection, Operations, Storage, and Transportation

    NASA Technical Reports Server (NTRS)

    1996-01-01

    NASA's standard for oxygen system design, materials selection, operation, and transportation is presented. Minimum guidelines applicable to NASA Headquarters and all NASA Field Installations are contained.

  17. Mars oxygen production system design

    NASA Technical Reports Server (NTRS)

    Cotton, Charles E.; Pillow, Linda K.; Perkinson, Robert C.; Brownlie, R. P.; Chwalowski, P.; Carmona, M. F.; Coopersmith, J. P.; Goff, J. C.; Harvey, L. L.; Kovacs, L. A.

    1989-01-01

    The design and construction phase is summarized of the Mars oxygen demonstration project. The basic hardware required to produce oxygen from simulated Mars atmosphere was assembled and tested. Some design problems still remain with the sample collection and storage system. In addition, design and development of computer compatible data acquisition and control instrumentation is ongoing.

  18. Mars oxygen production system design

    NASA Technical Reports Server (NTRS)

    1988-01-01

    This report summarizes the design and construction of the Mars oxygen demonstration project. The basic hardware required to produce oxygen from simulated Mars atmosphere has been assembled and tested. Some design problems still remain with the sample collection and storage system. In addition, design and development of computer data acquisition and control instrumentation is continuing.

  19. Biofilm spatial organization by the emerging pathogen Campylobacter jejuni: comparison between NCTC 11168 and 81-176 strains under microaerobic and oxygen-enriched conditions.

    PubMed

    Turonova, Hana; Briandet, Romain; Rodrigues, Ramila; Hernould, Mathieu; Hayek, Nabil; Stintzi, Alain; Pazlarova, Jarmila; Tresse, Odile

    2015-01-01

    During the last years, Campylobacter has emerged as the leading cause of bacterial foodborne infections in developed countries. Described as an obligate microaerophile, Campylobacter has puzzled scientists by surviving a wide range of environmental oxidative stresses on foods farm to retail, and thereafter intestinal transit and oxidative damage from macrophages to cause human infection. In this study, confocal laser scanning microscopy (CLSM) was used to explore the biofilm development of two well-described Campylobacter jejuni strains (NCTC 11168 and 81-176) prior to or during cultivation under oxygen-enriched conditions. Quantitative and qualitative appraisal indicated that C. jejuni formed finger-like biofilm structures with an open ultrastructure for 81-176 and a multilayer-like structure for NCTC 11168 under microaerobic conditions (MAC). The presence of motile cells within the biofilm confirmed the maturation of the C. jejuni 81-176 biofilm. Acclimation of cells to oxygen-enriched conditions led to significant enhancement of biofilm formation during the early stages of the process. Exposure to these conditions during biofilm cultivation induced an even greater biofilm development for both strains, indicating that oxygen demand for biofilm formation is higher than for planktonic growth counterparts. Overexpression of cosR in the poorer biofilm-forming strain, NCTC 11168, enhanced biofilm development dramatically by promoting an open ultrastructure similar to that observed for 81-176. Consequently, the regulator CosR is likely to be a key protein in the maturation of C. jejuni biofilm, although it is not linked to oxygen stimulation. These unexpected data advocate challenging studies by reconsidering the paradigm of fastidious requirements for C. jejuni growth when various subpopulations (from quiescent to motile cells) coexist in biofilms. These findings constitute a clear example of a survival strategy used by this emerging human pathogen.

  20. Relationships between composition and pulmonary toxicity of prototype particles from coal combustion and pyrolysis

    EPA Science Inventory

    The hypothesis that health effects associated with coal combustion fly-ash particles are exacerbated by the simultaneous presence of iron and soot was tested through two sets of experiments. The first set created prototype particles from complete and partial combustion, or oxygen...

  1. Modification of NASA Langley 8 foot high temperature tunnel to provide a unique national research facility for hypersonic air-breathing propulsion systems

    NASA Technical Reports Server (NTRS)

    Kelly, H. N.; Wieting, A. R.

    1984-01-01

    A planned modification of the NASA Langley 8-Foot High Temperature Tunnel to make it a unique national research facility for hypersonic air-breathing propulsion systems is described, and some of the ongoing supporting research for that modification is discussed. The modification involves: (1) the addition of an oxygen-enrichment system which will allow the methane-air combustion-heated test stream to simulate air for propulsion testing; and (2) supplemental nozzles to expand the test simulation capability from the current nominal Mach number to 7.0 include Mach numbers 3.0, 4.5, and 5.0. Detailed design of the modifications is currently underway and the modified facility is scheduled to be available for tests of large scale propulsion systems by mid 1988.

  2. An innovative system for supplying air and fuel mixture to a combustion chamber of an engine

    NASA Astrophysics Data System (ADS)

    Saikumar, G. R. Bharath

    2018-04-01

    Conventional carburetors are being used since decades to ensure that the desired ratio of air and fuel enters the combustion chamber for combustion for the purpose of generating power in an Spark Ignition(SI) internal combustion engine. However to increase the efficiency, the carburetor system is gradually being replaced by fuel injection systems. Fuel injection systems use injectors to supply pressurized fuel into the combustion chamber. Owing to the high initial and maintenance cost, carburetors are still ruling in the low cost vehicle domain. An innovative concept is conceived, which is an alternative method to the carburetor system to supply the air and fuel mixture to a combustion chamber of an engine. This system comprises of an inner hollow cylinder with minute holes drilled along its length with an outer cylinder capable of sliding along its length or its longitudinal axis. This system is placed in the venturi instead of the conventional carburetor system. Fuel enters from the bottom inlet of the inner cylinder and flows out through the holes provided along its length. The fuel flow from the inner cylinder is dependent on the size and the number of holes exposed at that instance by the sliding outer cylinder which in turn is connected to the throttle or accelerator.

  3. Effect [of] co-combustion of sewage sludge and biomass on combustion behavior and emissions in pulverized fuel systems

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Spliethoff, H.; Hein, K.R.G.

    1999-07-01

    Biomass not only has a considerable potential as an additional fuel source but also shows a reasonable cost level in comparison to other renewable energies. The practicable fuel types are both residual material from forestry and agriculture, such as wood or straw, and especially cultivated reproducible feedstock such as Miscanthus Sinensis, whole cereal plants, poplars, or willows. Besides as single fuel, it is also considered to be sensible to utilize biomass in co-combustion in existing firing systems, such as pc-fired power stations. Biomass or sewage sludge utilized as additional fuel in coal combustion systems has consequences on combustion behavior, emissions,more » corrosion and residual matter. The effects of burning sewage sludge and agricultural residuals such as straw and manure as well as specially grown energy plants in combination with coal were studied in a 0.5 MW pulverized fuel test facility and a 20 kW electrically heated combustor. A major aspect of the investigations had been the required preparation and milling of the additional fuels. The investigations showed that in co-combustion of straw with coal, a grinding of 6 mm and finer is sufficient. The definitely coarser milling degree of biomass delays combustion and is observable by in-flame measurements. The investigations reveal that biomass addition has a positive effect on emissions. Since biomass in most cases contains considerably less sulphur than coal, an increasing biomass share in the thermal output makes the SO{sub 2} emissions decrease proportionally. In addition, SO{sub 2} can partly be captured in the ash by the alkaline-earth fractions of the biomass ash. As for sewage sludge, the emissions of SO{sub 2} correlate with the sulphur content of the fuel and, hence, rise with an increasing share of this biomass. Independently from the type, biomass shows a considerably stronger release of volatile matter. This latter fact may have a positive impact on NOx emissions when NOx

  4. Performance Evaluation of an Oxygen Sensor as a Function of the Samaria Doped Ceria Film Thickness

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Sanghavi, Rahul P.; Nandasiri, Manjula I.; Kuchibhatla, Satyanarayana V N T

    The current demand in the automobile industry is in the control of air-fuel mixture in the combustion engine of automobiles. Oxygen partial pressure can be used as an input parameter for regulating or controlling systems in order to optimize the combustion process. Our goal is to identify and optimize the material system that would potentially function as the active sensing material for such a device that monitors oxygen partial pressure in these systems. We have used thin film samaria doped ceria (SDC) as the sensing material for the sensor operation, exploiting the fact that at high temperatures, oxygen vacancies generatedmore » due to samarium doping act as conducting medium for oxygen ions which hop through the vacancies from one side to the other contributing to an electrical signal. We have recently established that 6 atom % Sm doping in ceria films has optimum conductivity. Based on this observation, we have studied the variation in the overall conductivity of 6 atom % samaria doped ceria thin films as a function of thickness in the range of 50 nm to 300 nm at a fixed bias voltage of 2 volts. A direct proportionality in the increase in the overall conductivity is observed with the increase in sensing film thickness. For a range of oxygen pressure values from 1 mTorr to 100 Torr, a tolerable hysteresis error, good dynamic response and a response time of less than 10 seconds was observed« less

  5. Cascade heat recovery with coproduct gas production

    DOEpatents

    Brown, W.R.; Cassano, A.A.; Dunbobbin, B.R.; Rao, P.; Erickson, D.C.

    1986-10-14

    A process for the integration of a chemical absorption separation of oxygen and nitrogen from air with a combustion process is set forth wherein excess temperature availability from the combustion process is more effectively utilized to desorb oxygen product from the absorbent and then the sensible heat and absorption reaction heat is further utilized to produce a high temperature process stream. The oxygen may be utilized to enrich the combustion process wherein the high temperature heat for desorption is conducted in a heat exchange preferably performed with a pressure differential of less than 10 atmospheres which provides considerable flexibility in the heat exchange. 4 figs.

  6. Ignition delays, heats of combustion, and reaction rates of aluminum alkyl derivatives used as ignition and combustion enhancers for supersonic combustors

    NASA Technical Reports Server (NTRS)

    Ryan, T. W., III; Harlowe, W. W.; Schwab, S.

    1992-01-01

    The work was based on adapting an apparatus and procedure developed at Southwest Research Institute for rating the ignition quality of fuels for diesel engines. Aluminum alkyls and various Lewis-base adducts of these materials, both neat and mixed 50/50 with pure JP-10 hydrocarbon, were injected into the combustion bomb using a high-pressure injection system. The bomb was pre-charged with air that was set at various initial temperatures and pressures for constant oxygen density. The ignition delay times were determined for the test materials at these different initial conditions. The data are presented in absolute terms as well as comparisons with the parent alkyls. The relative heats of reaction of the various test materials were estimated based on a computation of the heat release, using the pressure data recorded during combustion in the bomb. In addition, the global reaction rates for each material were compared at a selected tmperature and pressure.

  7. A nonlinear dynamical system for combustion instability in a pulse model combustor

    NASA Astrophysics Data System (ADS)

    Takagi, Kazushi; Gotoda, Hiroshi

    2016-11-01

    We theoretically and numerically study the bifurcation phenomena of nonlinear dynamical system describing combustion instability in a pulse model combustor on the basis of dynamical system theory and complex network theory. The dynamical behavior of pressure fluctuations undergoes a significant transition from steady-state to deterministic chaos via the period-doubling cascade process known as Feigenbaum scenario with decreasing the characteristic flow time. Recurrence plots and recurrence networks analysis we adopted in this study can quantify the significant changes in dynamic behavior of combustion instability that cannot be captured in the bifurcation diagram.

  8. Formation and emission of large furans and oxygenated hydrocarbons from flames.

    PubMed

    Johansson, K Olof; Dillstrom, Tyler; Monti, Matteo; El Gabaly, Farid; Campbell, Matthew F; Schrader, Paul E; Popolan-Vaida, Denisia M; Richards-Henderson, Nicole K; Wilson, Kevin R; Violi, Angela; Michelsen, Hope A

    2016-07-26

    Many oxygenated hydrocarbon species formed during combustion, such as furans, are highly toxic and detrimental to human health and the environment. These species may also increase the hygroscopicity of soot and strongly influence the effects of soot on regional and global climate. However, large furans and associated oxygenated species have not previously been observed in flames, and their formation mechanism and interplay with polycyclic aromatic hydrocarbons (PAHs) are poorly understood. We report on a synergistic computational and experimental effort that elucidates the formation of oxygen-embedded compounds, such as furans and other oxygenated hydrocarbons, during the combustion of hydrocarbon fuels. We used ab initio and probabilistic computational techniques to identify low-barrier reaction mechanisms for the formation of large furans and other oxygenated hydrocarbons. We used vacuum-UV photoionization aerosol mass spectrometry and X-ray photoelectron spectroscopy to confirm these predictions. We show that furans are produced in the high-temperature regions of hydrocarbon flames, where they remarkably survive and become the main functional group of oxygenates that incorporate into incipient soot. In controlled flame studies, we discovered ∼100 oxygenated species previously unaccounted for. We found that large alcohols and enols act as precursors to furans, leading to incorporation of oxygen into the carbon skeletons of PAHs. Our results depart dramatically from the crude chemistry of carbon- and oxygen-containing molecules previously considered in hydrocarbon formation and oxidation models and spearhead the emerging understanding of the oxidation chemistry that is critical, for example, to control emissions of toxic and carcinogenic combustion by-products, which also greatly affect global warming.

  9. Formation and emission of large furans and oxygenated hydrocarbons from flames

    PubMed Central

    Johansson, K. Olof; Dillstrom, Tyler; Monti, Matteo; El Gabaly, Farid; Campbell, Matthew F.; Schrader, Paul E.; Popolan-Vaida, Denisia M.; Richards-Henderson, Nicole K.; Wilson, Kevin R.; Violi, Angela; Michelsen, Hope A.

    2016-01-01

    Many oxygenated hydrocarbon species formed during combustion, such as furans, are highly toxic and detrimental to human health and the environment. These species may also increase the hygroscopicity of soot and strongly influence the effects of soot on regional and global climate. However, large furans and associated oxygenated species have not previously been observed in flames, and their formation mechanism and interplay with polycyclic aromatic hydrocarbons (PAHs) are poorly understood. We report on a synergistic computational and experimental effort that elucidates the formation of oxygen-embedded compounds, such as furans and other oxygenated hydrocarbons, during the combustion of hydrocarbon fuels. We used ab initio and probabilistic computational techniques to identify low-barrier reaction mechanisms for the formation of large furans and other oxygenated hydrocarbons. We used vacuum-UV photoionization aerosol mass spectrometry and X-ray photoelectron spectroscopy to confirm these predictions. We show that furans are produced in the high-temperature regions of hydrocarbon flames, where they remarkably survive and become the main functional group of oxygenates that incorporate into incipient soot. In controlled flame studies, we discovered ∼100 oxygenated species previously unaccounted for. We found that large alcohols and enols act as precursors to furans, leading to incorporation of oxygen into the carbon skeletons of PAHs. Our results depart dramatically from the crude chemistry of carbon- and oxygen-containing molecules previously considered in hydrocarbon formation and oxidation models and spearhead the emerging understanding of the oxidation chemistry that is critical, for example, to control emissions of toxic and carcinogenic combustion by-products, which also greatly affect global warming. PMID:27410045

  10. Measurement of Muscle Protein Fractional Synthetic Rate by Capillary Gas Chromatography/Combustion Isotope Ratio Mass Spectrometry

    PubMed Central

    Yarasheski, Kevin E.; Smith, Kenneth; Rennie, Michael J.; Bier, Dennis M.

    2014-01-01

    The measurement of skeletal muscle protein fractional synthetic rate using an infusion of (1-13C)leucine and measuring the isotopic abundance of the tracer in skeletal muscle protein by preparative gas chromatography (GC)/ninhydrin isotope ratio mass spectrometry (IRMS) is laborious and subject to errors owing to contamination by 12C. The purpose of this study was to compare muscle (13C)leucine enrichment measured with the conventional preparative GC/ninhydrin IRMS approach to a new, continuous-flow technique using capillary GC/combustion IRMS. Quadriceps muscles were removed from four Sprague–Dawley rats after each was infused at a different rate with (1-13C)leucine for 6–8 h. Muscle leucine enrichment (at.% excess) measured by both methods differed by less than 4%, except at low (13C)leucine enrichments (<0.03 at.% excess). In addition, capillary GC/combustion IRMS was used to assess muscle (13C)leucine enrichment and fractional muscle protein synthesis rate in ten normal young men and women infused with (1,2-13C2)leucine for 12–14 h. This approach reduced the variability of the isotope abundance measure and gave estimates of muscle protein synthesis rate (0.050 ± 0.011% h−1 (mean ± SEM); range = 0.023–0.147% h−1) that agree with published values determined using the standard analytical approach. The measurement of (13C)leucine enrichment from skeletal muscle protein by capillary GC/combustion IRMS provides a simple, acceptable and practical alternative to preparative GC/ninhydrin IRMS. PMID:1420371

  11. Soot agglomeration in isolated, free droplet combustion

    NASA Technical Reports Server (NTRS)

    Choi, M. Y.; Dryer, F. L.; Green, G. J.; Sangiovanni, J. J.

    1993-01-01

    Under the conditions of an isolated, free droplet experiment, hollow, carbonaceous structures, called soot spheres, were observed to form during the atmospheric pressure, low Reynolds number combustion of 1-methylnaphthalene. These structures which are agglomerates composed of smaller spheroidal units result from both thermophoretic effects induced by the envelope flame surrounding each drop and aerodynamic effects caused by changes in the relative gas/drop velocities. A chemically reacting flow model was used to analyze the process of sootshell formation during microgravity droplet combustion. The time-dependent temperature and gas property field surrounding the droplet was determined, and the soot cloud location for microgravity combustion of n-heptane droplets was predicted. Experiments showed that the sooting propensity of n-alkane fuel droplets can be varied through diluent substitution, oxygen-index variations, and ambient pressure reductions.

  12. Combustion response to acoustic perturbation in liquid rocket engines

    NASA Astrophysics Data System (ADS)

    Ghafourian, Akbar

    An experimental study of the effect of acoustic perturbations on combustion behavior of a model liquid propellant rocket engine has been carried out. A pair of compression drivers were used to excite transverse and longitudinal acoustic fields at strengths of up to 156.6 dB and 159.5 dB respectively in the combustion chamber of the experimental rocket engine. Propellant simulants were injected into the combustion chamber through a single element shear coaxial injector. Water and air were used in cold flow studies and ethanol and oxygen-enriched air were used as fuel and oxidizer in reacting hot flow studies. In cold flow studies an imposed transverse acoustic field had a more pronounced effect on the spray pattern than a longitudinal acoustic fields. A transverse acoustic field widened the spray by as much as 33 percent and the plane of impingement of the spray with chamber walls moved up closer to the injection plane. The behavior was strongly influenced by the gas phase velocity but was less sensitive to changes in the liquid phase velocity. In reacting hot flow studies the effects of changes in equivalence ratio, excitation amplitude, excitation frequency, liquid and gas phase velocity and chamber pressure on the response of the injector to imposed high frequency transverse acoustic excitation were measured. Reducing the equivalence ratio from 7.4 to 3.8 increased the chamber pressure response to the imposed excitation at 3000 Hz. Increasing the excitation amplitude from 147 dB to 155.6 dB at 3000 Hz increased the chamber pressure response to the excitation. In the frequency range of 1240 Hz to 3220 Hz, an excitation frequency of 3000 Hz resulted in the largest response of the chamber pressure indicating the importance of fluid dynamic coupling. Increasing the liquid phase velocity from 9.2 m/sec to 22.7 m/sec, did not change the amplitude of the chamber pressure response to excitation. This implied the importance of local equivalence ratio and not the overall

  13. The influence of systemic hemodynamics and oxygen transport on cerebral oxygen saturation in neonates after the Norwood procedure.

    PubMed

    Li, Jia; Zhang, Gencheng; Holtby, Helen; Guerguerian, Anne-Marie; Cai, Sally; Humpl, Tilman; Caldarone, Christopher A; Redington, Andrew N; Van Arsdell, Glen S

    2008-01-01

    Ischemic brain injury is an important morbidity in neonates after the Norwood procedure. Its relationship to systemic hemodynamic oxygen transport is poorly understood. Sixteen neonates undergoing the Norwood procedure were studied. Continuous cerebral oxygen saturation was measured by near-infrared spectroscopy. Continuous oxygen consumption was measured by respiratory mass spectrometry. Pulmonary and systemic blood flow, systemic vascular resistance, oxygen delivery, and oxygen extraction ratio were derived with measurements of arterial, and superior vena cava and pulmonary venous gases and pressures at 2- to 4-hour intervals during the first 72 hours in the intensive care unit. Mean cerebral oxygen saturation was 66% +/- 12% before the operation, reduced to 51% +/- 13% on arrival in the intensive care unit, and remained low during the first 8 hours; it increased to 56% +/- 9% at 72 hours, still significantly lower than the preoperative level (P < .05). Postoperatively, cerebral oxygen saturation was closely and positively correlated with systemic arterial pressure, arterial oxygen saturation, and arterial oxygen tension and negatively with oxygen extraction ratio (P < .0001 for all). Cerebral oxygen saturation was moderately and positively correlated with systemic blood flow and oxygen delivery (P < .0001 for both). It was weakly and positively correlated with pulmonary blood flow (P = .001) and hemoglobin (P = .02) and negatively correlated with systemic vascular resistance (P = .003). It was not correlated with oxygen consumption (P > .05). Cerebral oxygen saturation decreased significantly in neonates during the early postoperative period after the Norwood procedure and was significantly influenced by systemic hemodynamic and metabolic events. As such, hemodynamic interventions to modify systemic oxygen transport may provide further opportunities to reduce the risk of cerebral ischemia and improve neurodevelopmental outcomes.

  14. Metallized Gelled Propellants: Oxygen/RP-1/aluminum Rocket Combustion Experiments

    NASA Technical Reports Server (NTRS)

    Palaszewski, Bryan; Zakany, James S.

    1995-01-01

    A series of combustion experiments were conducted to measure the specific impulse, Cstar-, and specific-impulse efficiencies of a rocket engine using metallized gelled liquid propellants. These experiments used a small 20- to 40-1bf (89- to 178-N) thrust, modular engine consisting of an injector, igniter, chamber and nozzle. The fuels used were traditional liquid RP-1 and gelled RP-1 with 0-, 5-, and 55-wt% loadings of aluminum and gaseous oxygen was the oxidizer. Ten different injectors were used during the testing: 6 for the baseline 02/RP-1 tests and 4 for the gelled fuel tests which covered a wide range of mixture ratios. At the peak of the Isp versus oxidizer-to-fuel ratio (O/F) data, a range of 93 to 99% Cstar efficiency was reached with ungelled 02/RP-1. A Cstar efficiency range of 75 to 99% was obtained with gelled RP-l (0-wt% RP-1/Al) while the metallized 5-wt% RP-1/Al delivered a Cstar efficiency of 94 to 99% at the peak Isp in the O/F range tested. An 88 to 99% Cstar efficiency was obtained at the peak Isp of the gelled RP1/Al with 55-wt% Al. Specific impulse efficiencies for the 55-wt% RP-1/Al of 67%-83% were obtained at a 2.4:1 expansion ratio. Injector erosion was evident with the 55-wt% testing, while there was little or no erosion seen with the gelled RP-1 with 0- and 5-wt% Al. A protective layer of gelled fuel formed in the firings that minimized the damage to the rocket injector face. This effect may provide a useful technique for engine cooling. These experiments represent a first step in characterizing the performance of and operational issues with gelled RP-1 fuels.

  15. NOx Emission Reduction by Oscillating combustion

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Institute of Gas Technology

    2004-01-30

    High-temperature, natural gas-fired furnaces, especially those fired with preheated air, produce large quantities of NO{sub x} per ton of material processed. Regulations on emissions from industrial furnaces are becoming increasingly more stringent. In addition, competition is forcing operators to make their furnaces more productive and/or efficient. Switching from preheated air to industrial oxygen can increase efficiency and reduce NO{sub x}, but oxygen is significantly more costly than air and may not be compatible with the material being heated. What was needed, and what was developed during this project, is a technology that reduces NO{sub x} emissions while increasing furnace efficiencymore » for both air- and oxy-fired furnaces. Oscillating combustion is a retrofit technology that involves the forced oscillation of the fuel flow rate to a furnace. These oscillations create successive, fuel-rich and fuel-lean zones within the furnace. Heat transfer from the flame to the load increases due to the more luminous fuel-rich zones, a longer overall flame length, and the breakup of the thermal boundary layer. The increased heat transfer shortens heat up times, thereby increasing furnace productivity, and reduces the heat going up the stack, thereby increasing efficiency. The fuel-rich and fuel-lean zones also produce substantially less NO{sub x} than firing at a constant excess air level. The longer flames and higher heat transfer rate reduces overall peak flame temperature and thus reduces additional NO{sub x} formation from the eventual mixing of the zones and burnout of combustibles from the rich zones. This project involved the development of hardware to implement oscillating combustion on an industrial scale, the laboratory testing of oscillating combustion on various types of industrial burners, and the field testing of oscillating combustion on several types of industrial furnace. Before laboratory testing began, a market study was conducted, based on the

  16. NOx Emission Reduction by Oscillating Combustion

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    John C. Wagner

    2004-03-31

    High-temperature, natural gas-fired furnaces, especially those fired with preheated air, produce large quantities of NO{sub x} per ton of material processed. Regulations on emissions from industrial furnaces are becoming increasingly more stringent. In addition, competition is forcing operators to make their furnaces more productive and/or efficient. Switching from preheated air to industrial oxygen can increase efficiency and reduce NO{sub x}, but oxygen is significantly more costly than air and may not be compatible with the material being heated. What was needed, and what was developed during this project, is a technology that reduces NO{sub x} emissions while increasing furnace efficiencymore » for both air- and oxy-fired furnaces. Oscillating combustion is a retrofit technology that involves the forced oscillation of the fuel flow rate to a furnace. These oscillations create successive, fuel-rich and fuel-lean zones within the furnace. Heat transfer from the flame to the load increases due to the more luminous fuel-rich zones, a longer overall flame length, and the breakup of the thermal boundary layer. The increased heat transfer shortens heat up times, thereby increasing furnace productivity, and reduces the heat going up the stack, thereby increasing efficiency. The fuel-rich and fuel-lean zones also produce substantially less NO{sub x} than firing at a constant excess air level. The longer flames and higher heat transfer rate reduces overall peak flame temperature and thus reduces additional NO{sub x} formation from the eventual mixing of the zones and burnout of combustibles from the rich zones. This project involved the development of hardware to implement oscillating combustion on an industrial scale, the laboratory testing of oscillating combustion on various types of industrial burners, and the field testing of oscillating combustion on several types of industrial furnace. Before laboratory testing began, a market study was conducted, based on the

  17. The Supernova Triggered Formation and Enrichment of Our Solar System

    NASA Astrophysics Data System (ADS)

    Gritschneder, M.; Lin, D. N. C.; Murray, S. D.; Yin, Q.-Z.; Gong, M.-N.

    2012-01-01

    We investigate the enrichment of the pre-solar cloud core with short-lived radionuclides, especially 26Al. The homogeneity and the surprisingly small spread in the ratio 26Al/27Al observed in the overwhelming majority of calcium-aluminium-rich inclusions in a vast variety of primitive chondritic meteorites places strong constraints on the formation of the solar system. Freshly synthesized radioactive 26Al has to be included and well mixed within 20 kyr. After discussing various scenarios including X-winds, asymptotic giant branch stars, and Wolf-Rayet stars, we come to the conclusion that triggering the collapse of a cold cloud core by a nearby supernova (SN) is the most promising scenario. We then narrow down the vast parameter space by considering the pre-explosion survivability of such a clump as well as the cross-section necessary for sufficient enrichment. We employ numerical simulations to address the mixing of the radioactively enriched SN gas with the pre-existing gas and the forced collapse within 20 kyr. We show that a cold clump of 10 M ⊙ at a distance of 5 pc can be sufficiently enriched in 26Al and triggered into collapse fast enough—within 18 kyr after encountering the SN shock—for a range of different metallicities and progenitor masses, even if the enriched material is assumed to be distributed homogeneously in the entire SN bubble. In summary, we envision an environment for the birthplace of the solar system 4.567 Gyr ago similar to the situation of the pillars in M16 nowadays, where molecular cloud cores adjacent to an H II region will be hit by an SN explosion in the future. We show that the triggered collapse and formation of the solar system as well as the required enrichment with radioactive 26Al are possible in this scenario.

  18. Oxygen isotope exchange between refractory inclusion in Allende and solar nebula gas.

    PubMed

    Yurimoto, H; Ito, M; Nagasawa, H

    1998-12-04

    A calcium-aluminum-rich inclusion (CAI) from the Allende meteorite was analyzed and found to contain melilite crystals with extreme oxygen-isotope composition (approximately 5 percent oxygen-16 enrichment relative to terrestrial oxygen-16). Some of the melilite is also anomalously enriched in oxygen-16 compared with oxygen isotopes measured in other CAIs. The oxygen isotopic variation measured among the minerals (melilite, spinel, and fassaite) indicates that crystallization of the CAI started from oxygen-16-rich materials that were probably liquid droplets in the solar nebula, and oxygen isotope exchange with the surrounding oxygen-16-poor nebular gas progressed through the crystallization of the CAI. Additional oxygen isotope exchange also occurred during subsequent reheating events in the solar nebula.

  19. Oxygen isotope exchange between refractory inclusion in allende and solar nebula Gas

    PubMed

    Yurimoto; Ito; Nagasawa

    1998-12-04

    A calcium-aluminum-rich inclusion (CAI) from the Allende meteorite was analyzed and found to contain melilite crystals with extreme oxygen-isotope compositions ( approximately 5 percent oxygen-16 enrichment relative to terrestrial oxygen-16). Some of the melilite is also anomalously enriched in oxygen-16 compared with oxygen isotopes measured in other CAIs. The oxygen isotopic variation measured among the minerals (melilite, spinel, and fassaite) indicates that crystallization of the CAI started from oxygen-16-rich materials that were probably liquid droplets in the solar nebula, and oxygen isotope exchange with the surrounding oxygen-16-poor nebular gas progressed through the crystallization of the CAI. Additional oxygen isotope exchange also occurred during subsequent reheating events in the solar nebula.

  20. Fuel/oxidizer-rich high-pressure preburners. [staged-combustion rocket engine

    NASA Technical Reports Server (NTRS)

    Schoenman, L.

    1981-01-01

    The analyses, designs, fabrication, and cold-flow acceptance testing of LOX/RP-1 preburner components required for a high-pressure staged-combustion rocket engine are discussed. Separate designs of injectors, combustion chambers, turbine simulators, and hot-gas mixing devices are provided for fuel-rich and oxidizer-rich operation. The fuel-rich design addresses the problem of non-equilibrium LOX/RP-1 combustion. The development and use of a pseudo-kinetic combustion model for predicting operating efficiency, physical properties of the combustion products, and the potential for generating solid carbon is presented. The oxygen-rich design addresses the design criteria for the prevention of metal ignition. This is accomplished by the selection of materials and the generation of well-mixed gases. The combining of unique propellant injector element designs with secondary mixing devices is predicted to be the best approach.

  1. TG-FTIR analysis on pyrolysis and combustion of marine sediment

    NASA Astrophysics Data System (ADS)

    Oudghiri, Fatiha; Allali, Nabil; Quiroga, José María; Rodríguez-Barroso, María Rocío

    2016-09-01

    In this paper, the pyrolysis and combustion of sediment have been compared using thermogravimetric analysis (TG) coupled with Fourier transform infrared spectrometry (TG-FTIR) analysis. The TG results showed that both the pyrolysis and combustion of sediment presented four weight loss stages, each. The evolving gaseous products during pyrolysis were H2O, CO2 and hydrocarbons, while combustion yielded considerable amounts of CO2, in addition to H2O, CO, Cdbnd C, Cdbnd O and NH3. Comparing the pyrolysis and combustion TG-FTIR curves, it is possible to evaluate the effect of oxygen presence in the temperature range of 200-600 °C, which increases the volatilisation rate of organic matter in sediment. For the better detection of organic and inorganic matter in sediment by TG-FTIR analysis it is recommended to work in combustion mode of sediment.

  2. Oxygen production System Models for Lunar ISRU

    NASA Technical Reports Server (NTRS)

    Santiago-Maldonado, Edgardo

    2007-01-01

    In-Situ Resource Utilization (ISRU) seeks to make human space exploration feasible; by using available resources from a planet or the moon to produce consumables, parts, and structures that otherwise would be brought from Earth. Producing these in situ reduces the mass of such that must be launched and doing so allows more payload mass' for each mission. The production of oxygen from lunar regolith, for life support and propellant, is one of the tasks being studied under ISRU. NASA is currently funding three processes that have shown technical merit for the production of oxygen from regolith: Molten Salt Electrolysis, Hydrogen Reduction of Ilmenite, and Carbothermal Reduction. The ISRU program is currently developing system models of, the , abovementioned processes to: (1) help NASA in the evaluation process to select the most cost-effective and efficient process for further prototype development, (2) identify key parameters, (3) optimize the oxygen production process, (4) provide estimates on energy and power requirements, mass and volume.of the system, oxygen production rate, mass of regolith required, mass of consumables, and other important parameters, and (5) integrate into the overall end-to-end ISRU system model, which could be integrated with mission architecture models. The oxygen production system model is divided into modules that represent unit operations (e.g., reactor, water electrolyzer, heat exchanger). Each module is modeled theoretically using Excel and Visual Basic for Applications (VBA), and will be validated using experimental data from on-going laboratory work. This modularity (plug-n-play) feature of each unit operation allows the use of the same model on different oxygen production systems simulations resulting in comparable results. In this presentation, preliminary results for mass, power, volume will be presented along with brief description of the oxygen production system model.

  3. Large Eddy Simulations of Colorless Distributed Combustion Systems

    NASA Astrophysics Data System (ADS)

    Abdulrahman, Husam F.; Jaberi, Farhad; Gupta, Ashwani

    2014-11-01

    Development of efficient and low-emission colorless distributed combustion (CDC) systems for gas turbine applications require careful examination of the role of various flow and combustion parameters. Numerical simulations of CDC in a laboratory-scale combustor have been conducted to carefully examine the effects of these parameters on the CDC. The computational model is based on a hybrid modeling approach combining large eddy simulation (LES) with the filtered mass density function (FMDF) equations, solved with high order numerical methods and complex chemical kinetics. The simulated combustor operates based on the principle of high temperature air combustion (HiTAC) and has shown to significantly reduce the NOx, and CO emissions while improving the reaction pattern factor and stability without using any flame stabilizer and with low pressure drop and noise. The focus of the current work is to investigate the mixing of air and hydrocarbon fuels and the non-premixed and premixed reactions within the combustor by the LES/FMDF with the reduced chemical kinetic mechanisms for the same flow conditions and configurations investigated experimentally. The main goal is to develop better CDC with higher mixing and efficiency, ultra-low emission levels and optimum residence time. The computational results establish the consistency and the reliability of LES/FMDF and its Lagrangian-Eulerian numerical methodology.

  4. Ignition and combustion of bulk metals in a microgravity environment

    NASA Technical Reports Server (NTRS)

    Branch, Melvyn C.; Daily, J. W.; Abbud-Madrid, Angel

    1994-01-01

    Knowledge of the oxidation, ignition, and combustion of bulk metals is important for fire safety in the production, management, and utilization of liquid and gaseous oxygen for ground based and space applications. This report summarizes research under NASA support to investigate the ignition and combustion characteristics of bulk metals under varying gravity conditions. Metal ignition and combustion have not been studied previously under these conditions and the results are important not only for improved fire safety but also to increase knowledge of basic ignition and combustion mechanisms. The studies completed to date have led to the development of a clean and reproducible ignition source and diagnostic techniques for combustion measurements and have provided normal gravity combustion data on ten different pure metals. Metal specimens were ignited using a xenon short-arc lamp and measurements were made of the radiant energy flux, surface temperature history, spectroscopy of surface and gas products, and surface morphology and chemistry. Elevated gravity was provided by the University of Colorado Geotechnical Centrifuge.

  5. Stagnation point reverse flow combustor for a combustion system

    NASA Technical Reports Server (NTRS)

    Zinn, Ben T. (Inventor); Neumeier, Yedidia (Inventor); Seitzman, Jerry M. (Inventor); Jagoda, Jechiel (Inventor); Hashmonay, Ben-Ami (Inventor)

    2007-01-01

    A combustor assembly includes a combustor vessel having a wall, a proximate end defining an opening and a closed distal end opposite said proximate end. A manifold is carried by the proximate end. The manifold defines a combustion products exit. The combustion products exit being axially aligned with a portion of the closed distal end. A plurality of combustible reactant ports is carried by the manifold for directing combustible reactants into the combustion vessel from the region of the proximate end towards the closed distal end.

  6. Oxygen Penalty for Waste Oxidation in an Advanced Life Support System: A Systems Approach

    NASA Technical Reports Server (NTRS)

    Pisharody, Suresh; Wignarajah, K.; Fisher, John

    2002-01-01

    Oxidation is one of a number of technologies that are being considered for waste management and resource recovery from waste materials generated on board space missions. Oxidation processes are a very effective and efficient means of clean and complete conversion of waste materials to sterile products. However, because oxidation uses oxygen there is an "oxygen penalty" associated either with resupply of oxygen or with recycling oxygen from some other source. This paper is a systems approach to the issue of oxygen penalty in life support systems and presents findings on the oxygen penalty associated with an integrated oxidation-Sabatier-Oxygen Generation System (OGS) for waste management in an Advanced Life Support System. The findings reveal that such an integrated system can be operated to form a variety of useful products without a significant oxygen penalty.

  7. Computational fluid dynamics study of pulverized coal combustion in blast furnace raceway

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Shen, Y.S.; Maldonado, D.; Guo, B.Y.

    In this work, a numerical model is used to study the flow and coal combustion along the coal plume in a large-scale setting simulating the lance-blowpipe-tuyere-raceway region of a blast furnace. The model formulation is validated against the measurements in terms of burnout for both low and high volatile coals. The typical phenomena related to coal combustion along the coal plume are simulated and analyzed. The effects of some operational parameters on combustion behavior are also investigated. The results indicate that oxygen as a cooling gas gives a higher coal burnout than methane and air. The underlying mechanism of coalmore » combustion is explored. It is shown that under the conditions examined, coal burnout strongly depends on the availability of oxygen and residence time. Moreover, the influences of two related issues, i.e. the treatment of volatile matter (VM) and geometric setting in modeling, are investigated. The results show that the predictions of final burnouts using three different VM treatments are just slightly different, but all comparable to the measurements. However, the influence of the geometric setting is not negligible when numerically examining the combustion of pulverized coal under blast furnace conditions.« less

  8. 77 FR 11385 - Security Considerations for Lavatory Oxygen Systems

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-27

    ... Considerations for Lavatory Oxygen Systems AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Interim... considerations for lavatory oxygen systems (77 FR 12550). The interim final rule addresses a security... oxygen systems installed inside the lavatories of most transport category airplanes. As a result, the FAA...

  9. Combustion of Na 2B 4O 7 + Mg + C to synthesis B 4C powders

    NASA Astrophysics Data System (ADS)

    Guojian, Jiang; Jiayue, Xu; Hanrui, Zhuang; Wenlan, Li

    2009-09-01

    Boron carbide powder was fabricated by combustion synthesis (CS) method directly from mixed powders of borax (Na 2B 4O 7), magnesium (Mg) and carbon. The adiabatic temperature of the combustion reaction of Na 2B 4O 7 + 6 Mg + C was calculated. The control of the reactions was achieved by selecting reactant composition, relative density of powder compact and gas pressure in CS reactor. The effects of these different influential factors on the composition and morphologies of combustion products were investigated. The results show that, it is advantageous for more Mg/Na 2B 4O 7 than stoichiometric ratio in Na 2B 4O 7 + Mg + C system and high atmosphere pressure in the CS reactor to increase the conversion degree of reactants to end product. The final product with the minimal impurities' content could be fabricated at appropriate relative density of powder compact. At last, boron carbide without impurities could be obtained after the acid enrichment and distilled water washing.

  10. Hydrothermal carbonization of typical components of municipal solid waste for deriving hydrochars and their combustion behavior.

    PubMed

    Lin, Yousheng; Ma, Xiaoqian; Peng, Xiaowei; Yu, Zhaosheng

    2017-11-01

    In this work, five typical components were employed as representative pseudo-components to indirectly complete previous established simulation system during hydrothermal carbonization (HTC) of municipal solid waste. The fuel characteristics and combustion behavior of HTC-derived hydrochars were evaluated. Results clearly illustrated that the energy ranks of hydrochars were upgraded after HTC. For paper and wood, superior combustion performances of their hydrochars could achieve under suitable conditions. While for food, none positive enrichments on combustion loss rate were observed for hydrochars due to its high solubilization and decomposition under hot compressed water. It was noteworthy that a new weight loss peak was detected for paper and food, suggesting that new compounds were formed. For rubber, the HTC process made the properties of styrene butadiene rubber more close to natural rubber. Therefore, the first peak of hydrochars became significantly intense. While for plastic, only physical changes of polypropylene and polyethylene were observed. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Combustion Control System Design of Diesel Engine via ASPR based Output Feedback Control Strategy with a PFC

    NASA Astrophysics Data System (ADS)

    Mizumoto, Ikuro; Tsunematsu, Junpei; Fujii, Seiya

    2016-09-01

    In this paper, a design method of an output feedback control system with a simple feedforward input for a combustion model of diesel engine will be proposed based on the almost strictly positive real-ness (ASPR-ness) of the controlled system for a combustion control of diesel engines. A parallel feedforward compensator (PFC) design scheme which renders the resulting augmented controlled system ASPR will also be proposed in order to design a stable output feedback control system for the considered combustion model. The effectiveness of our proposed method will be confirmed through numerical simulations.

  12. A system using solid ceramic oxygen electrolyte cells to measure oxygen fugacities in gas-mixing systems

    NASA Technical Reports Server (NTRS)

    Williams, R. J.; Mullins, O.

    1976-01-01

    Details are given for the construction and operation of a 101.3 kN/sq m (1 atmosphere) redox control system. A solid ceramic oxygen electrolyte cell is used to monitor the oxygen fugacity in the furnace. The system consists of a vertical quench, gas mixing furnace with heads designed for mounting the electrolyte cell and with facilities for inserting and removing the samples. The system also contains the high input impedance electronics necessary for measurements, a simplified version of a gas mixing apparatus, and devices for experiments under controlled rates of change relative to temperature and redox state. The calibration and maintenance of the system are discussed.

  13. JSC systems using solid ceramic oxygen electrolyte cells to measure oxygen fugacites in gas-mixing systems

    NASA Technical Reports Server (NTRS)

    Williams, R. J.; Mullins, O.

    1981-01-01

    Details are given for the construction and operation of a 101.3 KN/sq meter (1 atmosphere) redox control system. A solid ceramic oxygen electrolyte cell is used to monitor the oxygen fugacity in the furnace. The system consists of a vertical quench gas mixing furnace with heads designed for mounting the electrolyte cell and with facilities for inserting and removing the samples, a simplified version of a gas mixing apparatus, and devices for experiments under controlled rates of change of temperature. A thermogravimetric analysis system employing these techniques of redox control and measurement is also described. The calibration and maintenance of the system are discussed.

  14. Air liquefaction and enrichment system propulsion in reusable launch vehicles

    NASA Astrophysics Data System (ADS)

    Bond, W. H.; Yi, A. C.

    1994-07-01

    A concept is shown for a fully reusable, Earth-to-orbit launch vehicle with horizontal takeoff and landing, employing an air-turborocket for low speed and a rocket for high-speed acceleration, both using liquid hydrogen for fuel. The turborocket employs a modified liquid air cycle to supply the oxidizer. The rocket uses 90% pure liquid oxygen as its oxidizer that is collected from the atmosphere, separated, and stored during operation of the turborocket from about Mach 2 to 5 or 6. The takeoff weight and the thrust required at takeoff are markedly reduced by collecting the rocket oxidizer in-flight. This article shows an approach and the corresponding technology needs for using air liquefaction and enrichment system propulsion in a single-stage-to-orbit (SSTO) vehicle. Reducing the trajectory altitude at the end of collection reduces the wing area and increases payload. The use of state-of-the-art materials, such as graphite polyimide, in a direct substitution for aluminum or aluminum-lithium alloy, is critical to meet the structure weight objective for SSTO. Configurations that utilize 'waverider' aerodynamics show great promise to reduce the vehicle weight.

  15. Status on the Verification of Combustion Stability for the J-2X Engine Thrust Chamber Assembly

    NASA Technical Reports Server (NTRS)

    Casiano, Matthew; Hinerman, Tim; Kenny, R. Jeremy; Hulka, Jim; Barnett, Greg; Dodd, Fred; Martin, Tom

    2013-01-01

    Development is underway of the J -2X engine, a liquid oxygen/liquid hydrogen rocket engine for use on the Space Launch System. The Engine E10001 began hot fire testing in June 2011 and testing will continue with subsequent engines. The J -2X engine main combustion chamber contains both acoustic cavities and baffles. These stability aids are intended to dampen the acoustics in the main combustion chamber. Verification of the engine thrust chamber stability is determined primarily by examining experimental data using a dynamic stability rating technique; however, additional requirements were included to guard against any spontaneous instability or rough combustion. Startup and shutdown chug oscillations are also characterized for this engine. This paper details the stability requirements and verification including low and high frequency dynamics, a discussion on sensor selection and sensor port dynamics, and the process developed to assess combustion stability. A status on the stability results is also provided and discussed.

  16. Mechanistic Models for Ignition and Combustion of Metallic Powders in Different Environments

    DTIC Science & Technology

    2010-09-17

    relevant chemical species (e.g. oxygen inward or aluminum outward) using Eq. (8.1), which requires as coefficients a pre-exponent and an activation...same experimental configuration was employed to study ignition of aluminum particles in different oxidizers. For oxygen / nitrogen gas mixtures , both...different durations are shown for all environments. The profiles measured for Al combustion in oxygen / nitrogen mixtures are collected in Figs. 10.3

  17. Mechanism of influence water vapor on combustion characteristics of propane-air mixture

    NASA Astrophysics Data System (ADS)

    Larionov, V. M.; Mitrofanov, G. A.; Sachovskii, A. V.; Kozar, N. K.

    2016-01-01

    The article discusses the results of an experimental study of the effect of water vapor at the flame temperature. Propane-butane mixture with air is burning on a modified Bunsen burner. Steam temperature was varied from 180 to 260 degrees. Combustion parameters changed by steam temperature and its proportion in the mixture with the fuel. The fuel-air mixture is burned in the excess air ratio of 0.1. It has been established that the injection of steam changes the characteristics of combustion fuel-air mixture and increase the combustion temperature. The concentration of CO in the combustion products is substantially reduced. Raising the temperature in the combustion zone is associated with increased enthalpy of the fuel by the added steam enthalpy. Reducing the concentration of CO is caused by decrease in the average temperature in the combustion zone by applying steam. Concentration of active hydrogen radicals and oxygen increases in the combustion zone. That has a positive effect on the process of combustion.

  18. Detonation engine fed by acetylene-oxygen mixture

    NASA Astrophysics Data System (ADS)

    Smirnov, N. N.; Betelin, V. B.; Nikitin, V. F.; Phylippov, Yu. G.; Koo, Jaye

    2014-11-01

    The advantages of a constant volume combustion cycle as compared to constant pressure combustion in terms of thermodynamic efficiency has focused the search for advanced propulsion on detonation engines. Detonation of acetylene mixed with oxygen in various proportions is studied using mathematical modeling. Simplified kinetics of acetylene burning includes 11 reactions with 9 components. Deflagration to detonation transition (DDT) is obtained in a cylindrical tube with a section of obstacles modeling a Shchelkin spiral; the DDT takes place in this section for a wide range of initial mixture compositions. A modified ka-omega turbulence model is used to simulate flame acceleration in the Shchelkin spiral section of the system. The results of numerical simulations were compared with experiments, which had been performed in the same size detonation chamber and turbulent spiral ring section, and with theoretical data on the Chapman-Jouguet detonation parameters.

  19. The Diesel Combustion Collaboratory: Combustion Researchers Collaborating over the Internet

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    C. M. Pancerella; L. A. Rahn; C. Yang

    2000-02-01

    The Diesel Combustion Collaborator (DCC) is a pilot project to develop and deploy collaborative technologies to combustion researchers distributed throughout the DOE national laboratories, academia, and industry. The result is a problem-solving environment for combustion research. Researchers collaborate over the Internet using DCC tools, which include: a distributed execution management system for running combustion models on widely distributed computers, including supercomputers; web-accessible data archiving capabilities for sharing graphical experimental or modeling data; electronic notebooks and shared workspaces for facilitating collaboration; visualization of combustion data; and video-conferencing and data-conferencing among researchers at remote sites. Security is a key aspect of themore » collaborative tools. In many cases, the authors have integrated these tools to allow data, including large combustion data sets, to flow seamlessly, for example, from modeling tools to data archives. In this paper the authors describe the work of a larger collaborative effort to design, implement and deploy the DCC.« less

  20. 36th International Symposium on Combustion (ISOC2016)

    DTIC Science & Technology

    2016-12-01

    GREENHOUSE GASES / IC ENGINE COMBUSTION I GAS TURBINE COMBUSTION I NOVEL COMBUSTION CONCEPTS, TECHNOLOGIES AND SYSTEMS 15. SUBJECT TERMS Reaction...pollutants and greenhouse gases; IC engine combustion; Gas turbine combustion; Novel combustion concepts, technologies and systems 16. SECURITY...PLENARY LECTURE TRANSFER (15 min) am Turbulent Flames IC Engines Laminar Flames Reaction Kinetics Gas Turbines Soot Solid Fuels/Pollutants

  1. Reduction of gaseous pollutant emissions from gas turbine combustors using hydrogen-enriched jet fuel

    NASA Technical Reports Server (NTRS)

    Clayton, R. M.

    1976-01-01

    Recent progress in an evaluation of the applicability of the hydrogen enrichment concept to achieve ultralow gaseous pollutant emission from gas turbine combustion systems is described. The target emission indexes for the program are 1.0 for oxides of nitrogen and carbon monoxide, and 0.5 for unburned hydrocarbons. The basic concept utilizes premixed molecular hydrogen, conventional jet fuel, and air to depress the lean flammability limit of the mixed fuel. This is shown to permit very lean combustion with its low NOx production while simulataneously providing an increased flame stability margin with which to maintain low CO and HC emission. Experimental emission characteristics and selected analytical results are presented for a cylindrical research combustor designed for operation with inlet-air state conditions typical for a 30:1 compression ratio, high bypass ratio, turbofan commercial engine.

  2. Formation and emission of large furans and oxygenated hydrocarbons from flames

    DOE PAGES

    Johansson, K. Olof; Dillstrom, Tyler; Monti, Matteo; ...

    2016-07-07

    Many oxygenated hydrocarbon species formed during combustion, such as furans, are highly toxic and detrimental to human health and the environment. These species may also increase the hygroscopicity of soot and strongly influence the effects of soot on regional and global climate. However, large furans and associated oxygenated species have not previously been observed in flames, and their formation mechanism and interplay with polycyclic aromatic hydrocarbons (PAHs) are poorly understood. We report on a synergistic computational and experimental effort that elucidates the formation of oxygen-embedded compounds, such as furans and other oxygenated hydrocarbons, during the combustion of hydrocarbon fuels. Wemore » used ab initio and probabilistic computational techniques to identify low-barrier reaction mechanisms for the formation of large furans and other oxygenated hydrocarbons. We used vacuum-UV photoionization aerosol mass spectrometry and X-ray photoelectron spectroscopy to confirm these predictions. We show that fura ns are produced in the high- Temperature regions of hydrocarbon flames, where they remarkably survive and become the main functional group of oxygenates that incorporate into incipient soot. In controlled flame studies, we discovered ~100 oxygenated species previously unaccounted for. We found that large alcohols and enols act as precursors to furans, leading to incorporation of oxygen into the carbon skeletons of PAHs. Our results depart dramatically from the crude chemistry of carbonand oxygen-containing molecules previously considered in hydrocarbon formation and oxidation models and spearhead the emerging understanding of the oxidation chemistry that is critical, for example, to control emissions of toxic and carcinogenic combustion by-products, which also greatly affect global warming.« less

  3. Enhancement of burning velocity by dissociated oxygen atoms

    NASA Astrophysics Data System (ADS)

    Akashi, Haruaki; Yoshinaga, Tomokazu; Sasaki, Koichi

    2015-09-01

    Green technology, such as preventing global warming, has been developed for years. Researches on plasma assisted combustion is one of the technologies and have been done for investigating more efficient combustion, more efficient use of fossil fuel with plasmas or applying electric fields. In the ignition time delay analyses with the dissociated oxygen atoms which is generated by non-equilibrium plasma had significant effect on the ignition time. In this paper, dissociated oxygen could effect on burning velocity or not has been examined using CHEMKIN. As a result, no effect can be seen with dissociation degree of lower than 10-3. But there is an effect on the enhancement of burning velocity with higher degree of 10-3. At the dissociation degree of 5×10-2, the burning velocity is enhanced at a factor of 1.24. And it is found that the distributions of each species in front of preheat zone are completely different. The combustion process is proceeded several steps in advance, and generation of H2O, CO and CO2 can be seen before combustion in higher dissociation case. This work was supported by KAKENHI (22340170).

  4. Particle behavior and char burnout mechanisms under pressurized combustion conditions

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Bauer, C.M.; Spliethoff, H.; Hein, K.R.G.

    Combined cycle systems with coal-fired gas turbines promise highest cycle efficiencies for this fuel. Pressurized pulverized coal combustion, in particular, yields high cycle efficiencies due to the high flue gas temperatures possible. The main problem, however, is to ensure a flue gas clean enough to meet the high gas turbine standards with a dirty fuel like coal. On the one hand, a profound knowledge of the basic chemical and physical processes during fuel conversion under elevated pressures is required whereas on the other hand suitable hot gas cleaning systems need to be developed. The objective of this work was tomore » provide experimental data to enable a detailed description of pressurized coal combustion processes. A series of experiments were performed with two German hvb coals, Ensdorf and Goettelborn, and one German brown coal, Garzweiler, using a semi-technical scale pressurized entrained flow reactor. The parameters varied in the experiments were pressure, gas temperature and bulk gas oxygen concentration. A two-color pyrometer was used for in-situ determination of particle surface temperatures and particle sizes. Flue gas composition was measured and solid residue samples taken and subsequently analyzed. The char burnout reaction rates were determinated varying the parameters pressure, gas temperature and initial oxygen concentration. Variation of residence time was achieved by taking the samples at different points along the reaction zone. The most influential parameters on char burnout reaction rates were found to be oxygen partial pressure and fuel volatile content. With increasing pressure the burn-out reactions are accelerated and are mostly controlled by product desorption and pore diffusion being the limiting processes. The char burnout process is enhanced by a higher fuel volatile content.« less

  5. Oxygen-Methane Thruster

    NASA Technical Reports Server (NTRS)

    Pickens, Tim

    2012-01-01

    An oxygen-methane thruster was conceived with integrated igniter/injector capable of nominal operation on either gaseous or liquid propellants. The thruster was designed to develop 100 lbf (approximately 445 N) thrust at vacuum conditions and use oxygen and methane as propellants. This continued development included refining the design of the thruster to minimize part count and manufacturing difficulties/cost, refining the modeling tools and capabilities that support system design and analysis, demonstrating the performance of the igniter and full thruster assembly with both gaseous and liquid propellants, and acquiring data from this testing in order to verify the design and operational parameters of the thruster. Thruster testing was conducted with gaseous propellants used for the igniter and thruster. The thruster was demonstrated to work with all types of propellant conditions, and provided the desired performance. Both the thruster and igniter were tested, as well as gaseous propellants, and found to provide the desired performance using the various propellant conditions. The engine also served as an injector testbed for MSFC-designed refractory combustion chambers made of rhenium.

  6. Droplet Combustion Experiment on STS-94

    NASA Technical Reports Server (NTRS)

    2003-01-01

    Fuel ignites and burns in the Droplet Combustion Experiment (DCE) on STS-94 on July 12, 1997, MET:11/07:00 (approximate). DCE used various fuels -- in drops ranging from 1 mm (0.04 inches) to 5 mm (0.2 inches) -- and mixtures of oxidizers and inert gases to learn more about the physics of combustion in the simplest burning configuration, a sphere. The DCE was designed to investigate the fundamental combustion aspects of single, isolated droplets under different pressures and ambient oxygen concentrations for a range of droplet sizes varying between 2 and 5 mm. The experiment elapsed time is shown at the bottom of the composite image. The DCE principal investigator was Forman Williams, University of California, San Diego. The experiment was part of the space research investigations conducted during the Microgravity Science Laboratory-1R mission (STS-94, July 1-17 1997). Advanced combustion experiments will be a part of investigations plarned for the International Space Station. (1.3MB, 13-second MPEG, screen 320 x 240 pixels; downlinked video, higher quality not available) A still JPG composite of this movie is available at http://mix.msfc.nasa.gov/ABSTRACTS/MSFC-0300170.html.

  7. COMPARISON OF FEMTOSECOND AND NANOSECOND TWO PHOTON ABSORPTION LASER INDUCED FLUORESCENCE (TALIF) OF ATOMIC OXYGEN IN ATMOSPHERIC PRESSURE PLASMAS

    DTIC Science & Technology

    2016-08-01

    OXYGEN IN ATMOSPHERIC PRESSURE PLASMAS James D. Scofield (AFRL/RQQE) and James R. Gord (AFRL/RQTC) Electrical Systems Branch, Power and Control...Division (AFRL/RQQE) Combustion Branch, Turbine Engine Division (AFRL/RQTC) Jacob B. Schmidt and Sukesh Roy Spectral Energies LLC Brian Sands...LASER-INDUCED FLUORESCENCE (TALIF) OF ATOMIC OXYGEN IN ATMOSPHERIC PRESSURE PLASMAS 5a. CONTRACT NUMBER In-house 5b. GRANT NUMBER 5c. PROGRAM

  8. Fireside corrosion in oxy-fuel combustion of coal

    DOE PAGES

    Holcomb, Gordon R.; Tylczak, Joseph; Meier, Gerald H.; ...

    2011-08-01

    Oxy-fuel combustion is based on burning fossil fuels in a mixture of recirculated flue gas and oxygen, rather than in air. An optimized oxy-combustion power plant will have ultra-low emissions since the flue gas that results from oxy-fuel combustion consists almost entirely of CO2 and water vapor. Once the water vapor is condensed, it is relatively easy to sequester the CO2 so that it does not escape into the atmosphere. A variety of laboratory tests comparing air-firing to oxy-firing conditions, and tests examining specific simpler combinations of oxidants, were conducted at 650-700 C. Alloys studied included model Fe-Cr and Ni-Crmore » alloys, commercial ferritic steels, austenitic steels, and nickel base superalloys. Furthermore, the observed corrosion behavior shows accelerated corrosion even with sulfate additions that remain solid at the tested temperatures, encapsulation of ash components in outer iron oxide scales, and a differentiation between oxy-fuel combustion flue gas recirculation choices.« less

  9. Elements of oxygen production systems using Martian atmosphere

    NASA Technical Reports Server (NTRS)

    Ash, R. L.; Huang, J.-K.; Johnson, P. B.; Sivertson, W. E., Jr.

    1986-01-01

    Hardware elements have been studied in terms of their applicability to Mars oxygen production systems. Various aspects of the system design are discussed and areas requiring further research are identified. Initial work on system reliability is discussed and a methodology for applying expert system technology to the oxygen processor is described.

  10. Multiuser Droplet Combustion Apparatus Developed to Conduct Combustion Experiments

    NASA Technical Reports Server (NTRS)

    Myhre, Craig A.

    2001-01-01

    A major portion of the energy produced in the world today comes from the combustion or burning of liquid hydrocarbon fuels in the form of droplets. However, despite vigorous scientific examinations for over a century, researchers still lack a full understanding of many fundamental combustion processes of liquid fuels. Understanding how these fuel droplets ignite, spread, and extinguish themselves will help us develop more efficient ways of energy production and propulsion, as well as help us deal better with the problems of combustion-generated pollution and fire hazards associated with liquid combustibles. The ability to conduct more controlled experiments in space, without the complication of gravity, provides scientists with an opportunity to examine these complicated processes closely. The Multiuser Droplet Combustion Apparatus (MDCA) supports this continued research under microgravity conditions. The objectives are to improve understanding of fundamental droplet phenomena affected by gravity, to use research results to advance droplet combustion science and technology on Earth, and to address issues of fire hazards associated with liquid combustibles on Earth and in space. MDCA is a multiuser facility designed to accommodate different combustion science experiments. The modular approach permits the on-orbit replacement of droplet combustion principal investigator experiments such as different fuels, droplet-dispensing needles, and droplet-tethering mechanisms. Large components such as the avionics, diagnostics, and base-plate remain on the International Space Station to reduce the launch mass of new experiments. MDCA is also designed to operate in concert with ground systems on Earth to minimize the involvement of the crew during orbit.

  11. Navier-Stokes Entropy Controlled Combustion Instability Analysis for Liquid Propellants

    NASA Technical Reports Server (NTRS)

    Chung, T. J.; Yoon, W. S.

    1990-01-01

    Navier-Stokes solutions are used to calculate oscillatory components of pressure, velocity, and density, which in turn provide necessary data to compute energy growth factors to determine combustion instability. It is shown that wave instabilities are associated with changes in entropy and the space and time averages of oscillatory components of pressure, velocity and density, together with the mean flow field in the energy equation. Compressible laminar and turbulent flows and reacting flows with hydrogen/oxygen combustion are considered. The SSME combustion/thrust chamber is used for illustration of the theory. The analysis shows that the increase of mean pressure and disturbances consistently results in the increase of instability. It is shown that adequate combustion instability analysis requires at least third order nonlinearity in energy growth or decay.

  12. Regeneratively Cooled Liquid Oxygen/Methane Technology Development

    NASA Technical Reports Server (NTRS)

    Robinson, Joel W.; Greene, Christopher B.; Stout, Jeffrey

    2012-01-01

    The National Aeronautics & Space Administration (NASA) has identified Liquid Oxygen (LOX)/Liquid Methane (LCH4) as a potential propellant combination for future space vehicles based upon exploration studies. The technology is estimated to have higher performance and lower overall systems mass compared to existing hypergolic propulsion systems. NASA-Marshall Space Flight Center (MSFC) in concert with industry partner Pratt & Whitney Rocketdyne (PWR) utilized a Space Act Agreement to test an oxygen/methane engine system in the Summer of 2010. PWR provided a 5,500 lbf (24,465 N) LOX/LCH4 regenerative cycle engine to demonstrate advanced thrust chamber assembly hardware and to evaluate the performance characteristics of the system. The chamber designs offered alternatives to traditional regenerative engine designs with improvements in cost and/or performance. MSFC provided the test stand, consumables and test personnel. The hot fire testing explored the effective cooling of one of the thrust chamber designs along with determining the combustion efficiency with variations of pressure and mixture ratio. The paper will summarize the status of these efforts.

  13. THE SUPERNOVA TRIGGERED FORMATION AND ENRICHMENT OF OUR SOLAR SYSTEM

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Gritschneder, M.; Lin, D. N. C.; Murray, S. D.

    2012-01-20

    We investigate the enrichment of the pre-solar cloud core with short-lived radionuclides, especially {sup 26}Al. The homogeneity and the surprisingly small spread in the ratio {sup 26}Al/{sup 27}Al observed in the overwhelming majority of calcium-aluminium-rich inclusions in a vast variety of primitive chondritic meteorites places strong constraints on the formation of the solar system. Freshly synthesized radioactive {sup 26}Al has to be included and well mixed within 20 kyr. After discussing various scenarios including X-winds, asymptotic giant branch stars, and Wolf-Rayet stars, we come to the conclusion that triggering the collapse of a cold cloud core by a nearby supernovamore » (SN) is the most promising scenario. We then narrow down the vast parameter space by considering the pre-explosion survivability of such a clump as well as the cross-section necessary for sufficient enrichment. We employ numerical simulations to address the mixing of the radioactively enriched SN gas with the pre-existing gas and the forced collapse within 20 kyr. We show that a cold clump of 10 M{sub Sun} at a distance of 5 pc can be sufficiently enriched in {sup 26}Al and triggered into collapse fast enough-within 18 kyr after encountering the SN shock-for a range of different metallicities and progenitor masses, even if the enriched material is assumed to be distributed homogeneously in the entire SN bubble. In summary, we envision an environment for the birthplace of the solar system 4.567 Gyr ago similar to the situation of the pillars in M16 nowadays, where molecular cloud cores adjacent to an H II region will be hit by an SN explosion in the future. We show that the triggered collapse and formation of the solar system as well as the required enrichment with radioactive {sup 26}Al are possible in this scenario.« less

  14. Heat of Combustion of the Product Formed by the Reaction of Acetylene, Ethylene, and Diborane

    NASA Technical Reports Server (NTRS)

    Tannenbaum, Stanley

    1957-01-01

    The net heat of combustion of the product formed by the reaction of diborane with a mixture of acetylene and ethylene was found to be 20,440 +/- 150 Btu per pound for the reaction of liquid fuel to gaseous carbon dioxide, gaseous water, and solid boric oxide. The measurements were made in a Parr oxygen-bomb calorimeter, and the combustion was believed to be 98 percent complete. The estimated net-heat of combustion for complete combustion would therefore be 20,850 +/- 150 Btu per pound.

  15. Silylated Derivatives Retain Carbon and Alter Expected 13C-Tracer Enrichments Using Continuous Flow-Combustion-Isotope Ratio Mass Spectrometry

    PubMed Central

    Shinebarger, Steven R.; Haisch, Michael; Matthews, Dwight E.

    2008-01-01

    Continuous-flow inlets from oxidation reactors are commonly used systems for biological sample introduction into isotope ratio mass spectrometers (IRMS) to measure 13C enrichment above natural abundance. Because the samples must be volatile enough to pass through a gas chromatograph, silylated derivatization reactions are commonly used to modify biological molecules to add the necessary volatility. Addition of a t-butyldimethylsilyl (TBDMS) group is a common derivatization approach. However, we have found that samples do not produce the expected increment in measured 13C abundance as the TBDMS derivatives. We have made measurements of 13C enrichment of leucine and glutamate standards of known 13C enrichment using derivatives without silicon (N-acetyl n-propyl ester), with silicon (TBDMS), and an intermediate case. The measurements of 13C in amino acids derivatized without silicon were as expected. The 13C enrichment measurements using the TBDMS derivative were higher than expected, but could be corrected to produce the expected 13C enrichment measurement by IRMS if one carbon was removed per silicon. We postulate that the silicon in the derivative forms silicon carbide compounds in the heated cupric oxide reactor, rather than forming silicon dioxide. Doing so reduces the amount of CO2 formed from the carbon in the sample. Silylated derivatives retain carbon with the silicon and must be used carefully and with correction factors to measure 13C enrichments by continuous-flow IRMS. PMID:12510745

  16. Combustion influences on natural abundance nitrogen isotope ratio in soil and plants following a wildfire in a sub-alpine ecosystem.

    PubMed

    Huber, Edith; Bell, Tina L; Adams, Mark A

    2013-11-01

    This before-and-after-impact study uses the natural abundance N isotope ratio (δ(15)N) to investigate the effects of a wildfire on sub-alpine ecosystem properties and processes. We measured the (15)N signatures of soil, charred organic material, ash and foliage in three sub-alpine plant communities (grassland, heathland and woodland) in south-eastern Australia. Surface bulk soil was temporarily enriched in (15)N immediately after wildfire compared to charred organic material and ash in all plant communities. We associated the enrichment of bulk soil with fractionation of N during combustion and volatilization of N, a process that also explains the sequential enrichment of (15)N of unburnt leaves > ash > charred organic material in relation to duration and intensity of heating. The rapid decline in (15)N of bulk soil to pre-fire values indicates that depleted ash, containing considerable amounts of total N, was readily incorporated into the soil. Foliar δ(15)N also increased with values peaking 1 year post-fire. Foliar enrichment was foremost coupled with the release of enriched NH4(+) into the soil owing to isotopic discrimination during volatilization of soluble N and combustion of organic material. The mode of post-fire regeneration influenced foliar (15)N enrichment in two species indicating use of different sources of N following fire. The use of natural abundance of (15)N in soil, ash and foliage as a means of tracing transformation of N during wildfire has established the importance of combustion products as an important, albeit temporary source of inorganic N for plants regenerating after wildfire.

  17. RELATIONSHIPS BETWEEN COMPOSITION AND PULMONARY TOXICITY OF PROTOTYPE PARTICLES FROM COAL COMBUSTION AND PYROLYSIS (MONTREAL, CANADA)

    EPA Science Inventory

    The hypothesis that health effects associated with coal combustion fly-ash particles are exacerbated by the simultaneous presence of iron and soot was tested through two sets of experiments. The first set created prototype particles from complete and partial combustion, or oxygen...

  18. Molten salt synthesis of nitrogen and oxygen enriched hierarchically porous carbons derived from biomass via rapid microwave carbonization for high voltage supercapacitors

    NASA Astrophysics Data System (ADS)

    Cheng, Yinfeng; Li, Baoqiang; Huang, Yanjuan; Wang, Yaming; Chen, Junchen; Wei, Daqing; Feng, Yujie; Jia, Dechang; Zhou, Yu

    2018-05-01

    Nitrogen and oxygen enriched hierarchically porous carbons (NOHPCs) derived from biomass have been successfully prepared by rapid microwave carbonization coupled with molten salt synthesis method in only 4 min. ZnCl2 plays important roles as microwave absorber, chemical activation agent and porogen in this process. NOHPC-1:10 sample possesses the maximum specific surface area of 1899 m2 g-1 with a pore volume of 1.16 cm3 g-1 and mesopore ratio of 70%, as well as nitrogen content of 5.30 wt% and oxygen content of 14.12 wt%. When evaluated as an electrode in a three-electrode system with 6 M KOH electrolyte, the material exhibits a high specific capacitance of 276 F g-1 at 0.2 A g-1, with a good rate capability of 90.9% retention at 10 A g-1. More importantly, the symmetric supercapacitor based on NOHPC-1:10 in 1 M Na2SO4 electrolyte exhibits a high energy density of 13.9 Wh kg-1 at a power density of 120 W kg-1 in a wide voltage window of 0-1.6 V, an excellent cycling stability with 95% of capacitance retention after 10,000 cycles. Our strategy provides a facile and rapid way for the preparation of advanced carbon materials derived from biomass towards energy storage applications.

  19. Combustion Instability in an Acid-Heptane Rocket with a Pressurized-Gas Propellant Pumping System

    NASA Technical Reports Server (NTRS)

    Tischler, Adelbert O.; Bellman, Donald R.

    1951-01-01

    Results of experimental measurements of low-frequency combustion instability of a 300-pound thrust acid-heptane rocket engine were compared to the trends predicted by an analysis of combustion instability in a rocket engine with a pressurized-gas propellant pumping system. The simplified analysis, which assumes a monopropellant model, was based on the concept of a combustion the delay occurring from the moment of propellant injection to the moment of propellant combustion. This combustion time delay was experimentally measured; the experimental values were of approximately half the magnitude predicted by the analysis. The pressure-fluctuation frequency for a rocket engine with a characteristic length of 100 inches and operated at a combustion-chamber pressure of 280 pounds per square inch absolute was 38 cycles per second; the analysis indicated. a frequency of 37 cycles per second. Increasing combustion-chamber characteristic length decreased the pressure-fluctuation frequency, in conformity to the analysis. Increasing the chamber operating pressure or increasing the injector pressure drop increased the frequency. These latter two effects are contrary to the analysis; the discrepancies are attributed to the conflict between the assumptions made to simplify the analysis and the experimental conditions. Oxidant-fuel ratio had no apparent effect on the experimentally measured pressure-fluctuation frequency for acid-heptane ratios from 3.0 to 7.0. The frequencies decreased with increased amplitude of the combustion-chamber pressure variations. The analysis indicated that if the combustion time delay were sufficiently short, low-frequency combustion instability would be eliminated.

  20. Combustion characteristics of fine- and micro-pulverized coal in the mixture of O{sub 2}/CO{sub 2}

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Xiangyong Huang; Xiumin Jiang; Xiangxin Han

    The effects of oxygen concentration, particle size, and heating rate on the coal combustion characteristics under an O{sub 2}/CO{sub 2} atmosphere were investigated. The results indicated that the oxygen concentration played the most important role. As the oxygen concentration increases, the ignition and burnout temperatures decrease and the comprehensive combustion property index S increases. Moreover, the improvement of the oxygen concentration intensified the effects of the other factors. The ignition mechanism changes from hetero-homogeneous type to homogeneous type as the oxygen concentration increases. The ignition and burnout temperatures decrease slightly as the mean particle size decreases, and the index Smore » increases measurably as the mean particle size decreases. The heating rate has different effects on the ignition temperature, burnout temperature, and index S at different oxygen concentrations. 19 refs., 9 figs., 2 tabs.« less