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1

The Economics of Oxygen Enriched Air Production Via Membranes  

E-print Network

Oxygen enriched air combustion is a recognized approach to energy conservation. Conventional methods of producing oxygen enriched air: Pressure Swing Adsorption and Cryogenics, are energy-intensive and expensive. In this paper the economics of using...

Gollan, A.; Kleper, M. H.

1984-01-01

2

A hybrid process combining oxygen enriched air combustion and membrane separation for post-combustion carbon dioxide capture  

Microsoft Academic Search

For carbon dioxide capture and storage (CCS), similar to a large majority of industrial processes, the separation (i.e. capture) step dominates the costs of the technological chain. Based on a concept of minimal work of concentration, the evaluation of a tentative capture framework which combines an oxygen enrichment step before combustion and a CO2 capture step from flue gas has

Eric Favre; Roda Bounaceur; Denis Roizard

2009-01-01

3

Oxygen Enriched Combustion System Performance Study  

E-print Network

}ched combustlon systems are technically, envlronmentally and economically feasible and offer significant energy savings and/or productivity improvement, and then to verify the performance of selected systems in research furnaces. Tests of several commercial... for 35 - 100 percent oxygen. The absolute levels of the NO x emissions also depended on the furnace temperature. INTRODUCTION Oxygen enriched combustion has been found to have significant energy saving potential in industrial furnace applications...

Chen, S. L.; Kwan, Y.; Abele, A. R.; Silver, L. S.; Kobayashi, H.

4

Reduction of NO{sub x} and particulate emissions by using oxygen-enriched combustion air in a locomotive diesel engine.  

SciTech Connect

This paper discusses operational and emissions results obtained with a locomotive (two-cylinder, EMD 567B) research diesel engine when oxygen-enriched combustion air is used. An operating regime was identified in which particulates and NO{sub x} could be reduced simultaneously when the concentration of intake air oxygen, fueling rate, and injection timing were optimized. Using oxygen from an external source, particulates were reduced by approximately 60% and NO{sub x} emissions were reduced by 15--20% with the optimal operating strategy. Higher gross power, lower peak cylinder pressures, and lower brake-specific fuel consumption were also observed. Gross power was increased by about 15--20% at base peak combustion pressure, and gross brake-specific fuel consumption was decreased by 2--10% with load. The effect of achieving oxygen enrichment by means of an air separation membrane is beyond the scope of the current study.

Poola, R. B.; Sekar, R. R.; Energy Systems; Electro-Motive Div., General Motors Corp.

2003-04-01

5

Studies of MHD generator performance with oxygen enriched coal combustion  

NASA Astrophysics Data System (ADS)

This paper presents calculations made using the Aerodyne PACKAGE (Plasma Analysis, Chemical Kinetics, and Generator Efficiency) computer code which bear on two questions which arise in connection with choices between oxygen enrichment and air preheating to attain the high combustion temperatures needed for open-cycle, coal-fired MHD power generation. The first question is which method produces the highest enthalpy extraction per unit channel length. The second is, in test facilities intended to study tradeoffs between oxygen enrichment and preheated air, can good generator performance be obtained from the same physical channel for different combustor compositions. The answer to the first question is found to depend on what combustor conditions are taken to be comparable. As for the second question, it is found that operation with channel input from off-design combustor conditions can cause serious problems, which can be partially alleviated by changing the channel load factors.

Wormhoudt, J.; Yousefian, V.; Kolb, C. E.; Martinez-Sanchez, M.

1980-07-01

6

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

PubMed

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. PMID:21382872

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

2011-10-01

7

REDUCTION OF NOx EMISSION FROM COAL COMBUSTION THROUGH OXYGEN ENRICHMENT  

SciTech Connect

BOC Process Gas Solutions and Western Research Institute (WRI) conducted a pilot-scale test program to evaluate the impact of oxygen enrichment on the emissions characteristics of pulverized coal. The combustion test facility (CTF) at WRI was used to assess the viability of the technique and determine the quantities of oxygen required for NOx reduction from coal fired boiler. In addition to the experimental work, a series of Computational Fluid Dynamics (CFD) simulations were made of the CTF under comparable conditions. A series of oxygen enrichment test was performed using the CTF. In these tests, oxygen was injected into one of the following streams: (1) the primary air (PA), (2) the secondary air (SA), and (3) the combined primary and secondary air. Emission data were collected from all tests, and compared with the corresponding data from the baseline cases. A key test parameter was the burner stoichiometry ratio. A series of CFD simulation models were devised to mimic the initial experiments in which secondary air was enriched with oxygen. The results from these models were compared against the experimental data. Experimental evidence indicated that oxygen enrichment does appear to be able to reduce NOx levels from coal combustion, especially when operated at low over fire air (OFA) levels. The reductions observed however are significantly smaller than that reported by others (7-8% vs. 25-50%), questioning the economic viability of the technique. This technique may find favor with fuels that are difficult to burn or stabilize at high OFA and produce excessive LOI. While CFD simulation appears to predict NO amounts in the correct order of magnitude and the correct trend with staging, it is sensitive to thermal conditions and an accurate thermal prediction is essential. Furthermore, without development, Fluent's fuel-NO model cannot account for a solution sensitive fuel-N distribution between volatiles and char and thus cannot predict the trends seen in the experiment.

Western Research Institute

2006-07-01

8

Utilization of oxygen-enriched air in diesel engines: Fundamental considerations  

SciTech Connect

Utilization of oxygen-enriched air in diesel engines holds potential for low exhaust smoke and particulate emissions. The majority of the oxygen-enriched-air combustion-related studies so far are experimental in nature, where the observed results are understood on an overall basis. This paper deals with the fundamental considerations associated with the oxygen-enriched air-fuel combustion process to enhance understanding of the concept. The increase in adiabatic flame temperature, the composition of exhaust gases at equilibrium, and also the changes in thermodynamic and transport properties due to oxygen-enrichment of standard intake air are computed. The effects of oxygen-enrichment on fuel evaporation rate, ignition delay, and premixed burnt fraction are also evaluated. Appropriate changes in the ignition delay correlation to reflect the effects of oxygen-enrichment are proposed. The notion of oxygen-enrichment of standard intake air as being akin to leaning of the fuel-air mixture is refuted on the basis of the fundamentally different requirements for the oxygen-enriched combustion process.

Lahiri, D.; Mehta, P.S. [Indian Inst. of Tech., Madras (India); Poola, R.B.; Sekar, R. [Argonne National Lab., IL (United States)

1997-09-01

9

Simulation studies of diesel engine performance with oxygen enriched air and water emulsified fuels  

SciTech Connect

A computer simulation code of a turbocharged, turbocompound diesel engine was modified to study the effects of using oxygen-enriched combustion air and water-emulsified diesel fuels. Oxygen levels of 21 percent to 40 percent by volume in the combustion air were studied. Water content in the fuel was varied from 0 percent to 50 percent mass. Simulation studies and a review and analysis of previous work in this area led to the following conclusions about expected engine performance and emissions: the power density of the engine is significantly increased by oxygen enrichment. Ignition delay and particulate emissions are reduced. Combustion temperatures and No{sub x} emissions are increased with oxygen enrichment but could be brought back to the base levels by introducing water in the fuel. The peak cylinder pressure which increases with the power output level might result in mechanical problems with engine components. Oxygen enrichment also provides an opportunity to use cheaper fuel such as No. 6 diesel fuel. Overall, the adverse effects of oxygen enrichment could be countered by the addition of water and it appears that an optimum combination of water content, oxygen level, and base diesel fuel quality may exist. This could yield improved performance and emissions characteristics compared to a state-of-the-art diesel engine. 9 refs., 8 figs.

Assanis, D.N.; Baker, D. (Illinois Univ., Urbana, IL (USA)); Sekar, R.R.; Siambekos, C.T.; Cole, R.L.; Marciniak, T.J. (Argonne National Lab., IL (USA))

1990-01-01

10

Diesel cogeneration plant using oxygen enriched air and emulsified fuels  

SciTech Connect

The investigation of oxygen-enriched combustion of alternative fuels in diesel engines at Argonne National Laboratory (ANL) is based on information gathered from two previous Department of Energy programs. The first was the slow-speed diesel engine program which used fuels such as coal-water slurry and coal derived liquid fuels in a slow speed diesel engine. The second was the development of membrane oxygen separation equipment. The results of these programs indicated that using the new membrane oxygen enrichment technology with medium- and high-speed diesel engines would do two things. First, oxygen enrichment could reduce some emissions from stationary diesel engines, particularly smoke, particulates and hydrocarbons while significantly increasing power output. The second, was that it might be possible to use less expensive liquid fuels such as No. 4, No. 6 and residual oil emulsified with water in medium- to high-speed diesel engines. The water would (1) help to eliminate the undesirable increase in nitrogen oxide production when enriched oxygen is used, and (2) by reducing the viscosity of the heavier liquid fuels, make them easier to use in smaller industrial cogeneration applications. This program consists of four steps: preliminary feasibility study, exploratory experiments, system development, and demonstration and commercialization of an industrial cogeneration system. 3 refs., 13 figs.

Marciniak, T.J.; Cole, R.L.; Sekar, R.R.; Stodolsky, F. (Argonne National Lab., IL (USA)); Eustis, J.N. (USDOE, Washington, DC (USA))

1990-01-01

11

Utilizing intake-air oxygen-enrichment technology to reduce cold- phase emissions  

SciTech Connect

Oxygen-enriched combustion is a proven, serious considered technique to reduce exhaust hydrocarbons (HC) and carbon monoxide (CO) emissions from automotive gasoline engines. This paper presents the cold-phase emissions reduction results of using oxygen-enriched intake air containing about 23% and 25% oxygen (by volume) in a vehicle powered by a spark-ignition (SI) engine. Both engineout and converter-out emissions data were collected by following the standard federal test procedure (FTP). Converter-out emissions data were also obtained employing the US Environmental Protection Agency`s (EPA`s) ``Off-Cycle`` test. Test results indicate that the engine-out CO emissions during the cold phase (bag 1) were reduced by about 46 and 50%, and HC by about 33 and 43%, using nominal 23 and 25% oxygen-enriched air compared to ambient air (21% oxygen by volume), respectively. However, the corresponding oxides of nitrogen (NO{sub x}) emissions were increased by about 56 and 79%, respectively. Time-resolved emissions data indicate that both HC and CO emissions were reduced considerably during the initial 127 s of the cold-phase FTP, without any increase in NO, emissions in the first 25 s. Hydrocarbon speciation results indicate that all major toxic pollutants, including ozone-forming specific reactivity factors, such as maximum incremental reactivity (NUR) and maximum ozone incremental reactivity (MOIR), were reduced considerably with oxygen-enrichment. Based on these results, it seems that using oxygen-enriched intake air during the cold-phase FTP could potentially reduce HC and CO emissions sufficiently to meet future emissions standards. Off-cycle, converter-out, weighted-average emissions results show that both HC and CO emissions were reduced by about 60 to 75% with 23 or 25% oxygen-enrichment, but the accompanying NO{sub x}, emissions were much higher than those with the ambient air.

Poola, R.B.; Ng, H.K.; Sekar, R.R. [Argonne National Lab., IL (United States); Baudino, J.H. [Autoresearch Labs., Inc., Chicago, IL (United States); Colucci, C.P. [National Renewable Energy Lab., Golden, CO (United States)

1995-12-31

12

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

Microsoft Academic Search

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

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

1993-01-01

13

Demonstration of oxygen-enriched combustion system on a light-duty vehicle to reduce cold-start emissions  

SciTech Connect

The oxygen content in the ambient air drawn by combustion engines can be increased by polymer membranes. The authors have previously demonstrated that 23 to 25% (concentration by volume) oxygen-enriched intake air can reduce hydrocarbons (HC), carbon monoxide (CO), air toxics, and ozone-forming potential (OFP) from flexible-fueled vehicles (FFVs) that use gasoline or M85. When oxygen-enriched air was used only during the initial start-up and warm-up periods, the emission levels of all three regulated pollutants [CO, nonmethane hydrocarbons (NMHC), and NO{sub x}] were lower than the U.S. EPA Tier II (year 2004) standards (without adjusting for catalyst deterioration factors). In the present work, an air separation membrane module was installed on the intake of a 2.5-L FFV and tested at idle and free acceleration to demonstrate the oxygen-enrichment concept for initial start-up and warm-up periods. A bench-scale, test set-up was developed to evaluate the air separation membrane characteristics for engine applications. On the basis of prototype bench tests and from vehicle tests, the additional power requirements and module size for operation of the membrane during the initial period of the cold-phase, FTP-75 cycle were evaluated. A prototype membrane module (27 in. long, 3 in. in diameter) supplying about 23% oxygen-enriched air in the engine intake only during the initial start-up and warm-up periods of a 2.5-L FFV requires additional power (blower) of less than one horsepower. With advances in air separation membranes to develop compact modules, oxygen enrichment of combustion air has the potential of becoming a more practical technique for controlling exhaust emissions from light-duty vehicles.

Sekar, R.; Poola, R.B.

1997-08-01

14

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

DOEpatents

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.

Poola, Ramesh B. (Woodridge, IL); Sekar, Ramanujam R. (Naperville, IL); Stork, Kevin C. (Chicago, IL)

1997-01-01

15

Application of oxygen-enriched combustion for locomotive diesel engines. Phase 1  

SciTech Connect

A thermodynamic simulation is used to study the effects of oxygen-enriched intake air on the performance and nitrogen oxide (NO) emissions of a locomotive diesel engine. The parasitic power of the air separation membrane required to supply the oxygen-enriched air is also estimated. For a given constraint on peak cylinder pressure, the gross and net power outputs of an engine operating under different levels of oxygen enrichment are compared with those obtained when a high-boost turbocharged engine is used. A 4% increase in peak cylinder pressure can result in an increase in net engine power of approximately 13% when intake air with an oxygen content of 28% by volume is used and fuel injection timing is retarded by 4 degrees. When the engine is turbocharged to a higher inlet boost, the same increase in peak cylinder pressure improves power by only 4%. If part of the significantly higher exhaust enthalpies available as a result of oxygen enrichment are recovered, the power requirements of the air separator membrane can be met, resulting in substantial net power improvements. Oxygen enrichment reduces particulate and visible smoke emissions but increases NO emissions. However, a combination of retarded fuel injection timing and post-treatment of exhaust gases may be adequate to meet the locomotive diesel engine NO{sub x} standards. Exhaust gas after-treatment and heat recovery would be required to realize the full potential of oxygen enrichment. Economic analysis shows that oxygen-enrichment technology is economically feasible and provides high returns on investment. The study also indicates the strong influence of membrane parasitic requirements and exhaust energy recovery on economic benefits. To obtain an economic advantage while using a membrane with higher parasitic power requirements, it is necessary to recover a part of the exhaust energy.

Poola, R.B.; Sekar, R.R.; Assanis, D.N.

1996-09-01

16

Experimental and analytical study to model temperature profiles and stoichiometry in oxygen-enriched in-situ combustion  

E-print Network

EXPERIMENTAL AND ANALYTICAL STUDY TO MODEL TEMPERATURE PROFILES AND STOICHIOMETRY IN OXYGEN-ENRICHED IN-SITU COMBUSTION A Dissertation by JOSE RAMON RODRIGUEZ Submitted to the Office of Graduate Studies of Texas A... AND STOICHIOMETRY IN OXYGEN-ENRICHED IN-SITU COMBUSTION A Dissertation by JOSE RAMON RODRIGUEZ Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of DOCTOR...

Rodriguez, Jose Ramon

2004-09-30

17

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

DOEpatents

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.

Balachandran, Uthamalingam (Hinsdale, IL); Bose, Arun C. (Pittsburgh, PA); McIlvried, Howard G. (Pittsburgh, PA)

2001-01-01

18

Novel Membranes and Processes for Oxygen Enrichment  

SciTech Connect

The overall goal of this project is to develop a membrane process that produces air containing 25-35% oxygen, at a cost of $25-40/ton of equivalent pure oxygen (EPO2). Oxygen-enriched air at such a low cost will allow existing air-fueled furnaces to be converted economically to oxygen-enriched furnaces, which in turn will improve the economic and energy efficiency of combustion processes significantly, and reduce the cost of CO{sub 2} capture and sequestration from flue gases throughout the U.S. manufacturing industries. During the 12-month Concept Definition project: We identified a series of perfluoropolymers (PFPs) with promising oxygen/nitrogen separation properties, which were successfully made into thin film composite membranes. The membranes showed oxygen permeance as high as 1,200 gpu and oxygen/nitrogen selectivity of 3.0, and the permeance and selectivity were stable over the time period tested (60 days). We successfully scaled up the production of high-flux PFP-based membranes, using MTR's commercial coaters. Two bench-scale spiral-wound modules with countercurrent designs were made and parametric tests were performed to understand the effect of feed flow rate and pressure, permeate pressure and sweep flow rate on the membrane module separation properties. At various operating conditions that modeled potential industrial operating conditions, the module separation properties were similar to the pure-gas separation properties in the membrane stamps. We also identified and synthesized new polymers [including polymers of intrinsic microporosity (PIMs) and polyimides] with higher oxygen/nitrogen selectivity (3.5-5.0) than the PFPs, and made these polymers into thin film composite membranes. However, these membranes were susceptible to severe aging; pure-gas permeance decreased nearly six-fold within two weeks, making them impractical for industrial applications of oxygen enrichment. We tested the effect of oxygen-enriched air on NO{sub x} emissions using a Bloom baffle burner at GTI. The results are positive and confirm that oxygen-enriched combustion can be carried out without producing higher levels of NOx than normal air firing, if lancing of combustion air is used and the excess air levels are controlled. A simple economic study shows that the membrane processes can produce O{sub 2} at less than $40/ton EPO{sub 2} and an energy cost of 1.1-1.5 MMBtu/ton EPO{sub 2}, which are very favorable compared with conventional technologies such as cryogenics and vacuum pressure swing adsorption processes. The benefits of integrated membrane processes/combustion process trains have been evaluated, and show good savings in process costs and energy consumption, as well as reduced CO{sub 2} emissions. For example, if air containing 30% oxygen is used in natural gas furnaces, the net natural gas savings are an estimated 18% at a burner temperature of 2,500 F, and 32% at a burner temperature of 3,000 F. With a 20% market penetration of membrane-based oxygen-enriched combustion in all combustion processes by 2020, the energy savings would be 414-736 TBtu/y in the U.S. The comparable net cost savings are estimated at $1.2-2.1 billion per year by 2020, calculated as the value of fuel savings subtracted from the cost of oxygen production. The fuel savings of 18%-32% by the membrane/oxygen-enriched combustion corresponds to an 18%-32% reduction in CO{sub 2} emissions, or 23-40 MM ton/y less CO{sub 2} from natural gas-fired furnaces by 2020. In summary, results from this project (Concept Definition phase) are highly promising and clearly demonstrate that membrane processes can produce oxygen-enriched air in a low cost manner that will lower operating costs and energy consumption in industrial combustion processes. Future work will focus on proof-of-concept bench-scale demonstration in the laboratory.

Lin, Haiqing

2011-11-15

19

Efficiency evaluation of oxygen enrichment in energy conversion processes  

SciTech Connect

The extent to which energy conversion efficiencies can be increased by using oxygen or oxygen-enriched air for combustion was studied. Combustion of most fuels with oxygen instead of air was found to have five advantages: increases combustion temperature and efficiency, improves heat transfer at high temperatures, reduces nitrous oxide emissions, permits a high ration of exhaust gas recirculation and allows combustion of certain materials not combustible in air. The same advantages, although to a lesser degree, are apparent with oxygen-enriched air. The cost-effectiveness of the process must necessarily be improved by about 10% when using oxygen instead of air before such use could become justifiable on purely economic terms. Although such a modest increase appears to be attainable in real situations, this study ascertained that it is not possible to generally assess the economic gains. Rather, each case requires its own evaluation. For certain processes industry has already proven that the use of oxygen leads to more efficient plant operation. Several ideas for essentially new applications are described. Specifically, when oxygen is used with exhaust gas recirculation in external or internal combustion engines. It appears also that the advantages of pulse combustion can be amplified further if oxygen is used. When burning wet fuels with oxygen, direct steam generation becomes possible. Oxygen combustion could also improve processes for in situ gasification of coals, oil shales, peats, and other wet fuels. Enhanced oil recovery by fire flooding methods might also become more effective if oxygen is used. The cold energy contained in liquid oxygen can be substantially recovered in the low end of certain thermodynamic cycles. Further efforts to develop certain schemes for using oxygen for combustion appear to be justified from both the technical and economic viewpoints.

Bomelburg, H.J.

1983-12-01

20

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

DOEpatents

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.

Poola, Ramesh B. (Woodridge, IL); Sekar, Ramanujam R. (Naperville, IL); Cole, Roger L. (Elmhurst, IL)

1997-01-01

21

Waste to energy operability enhancement under waste uncertainty via oxygen enrichment.  

PubMed

Waste to energy (WTE) performance is evaluated by maximization of electrical energy production and throughput, while maintaining low operational costs and complying with emission limits. Uncertainty in the quantities, composition and heating values of received wastes, pose severe operability problems and impair performance and emissions. The present work demonstrates and quantifies the possibility of improving WTE efficiency under feedstock uncertainty via oxygen enrichment of the combustion air. Acting essentially as a nitrogen depletion mechanism, oxygen enrichment has reverse effects compared to excess air (EA); synergistic use provides extended capabilities for performance improvement, without impairing final emissions, while satisfying capacity constraints. Increased oxygen enrichment is required at higher EA to maintain temperature. Lower charging rates of rich wastes (plastics, paper, etc.) or diminishing heating values, require higher oxygen enrichment or lower EA. The opposite holds for lower charging rates of poor wastes (biodegradables, biosludge, inerts, etc.) or rising heating values. The results establish the possibility of nominal designs to respond to feedstock variations and may be useful for low range excess air operation (low cost) or adiabatic operation (high EA, combustor temperature controlled by large fluegas volumes). The vector formulation facilitates digital coding for applications featuring multiple waste mixture variability. A 700000 tpa WTE facility in Athens, now under public-private-partnership contract tender is investigated. PMID:25036380

Tsiliyannis, Christos Aristeides

2014-08-19

22

Phenomena of fault-arc propagation on cables and wires for space applications in vacuum and oxygen-enriched atmosphere and air  

Microsoft Academic Search

Investigations of fault arc propagation on spacecraft cables under spacecraft specific conditions, e.g. vacuum, normal and oxygen enriched atmosphere have been performed. Typical patterns of fault arc extinction have been identified and their consequences with respect to causes of damages are discussed. The results indicate that for a given test current and test voltage the behavior of the arc and

F. R. Frontzek; D. Koenig; M. D. Judd; H. J. Reher

1994-01-01

23

COMBUSTION OF COAL IN AN OPPOSED FLOW DIFFUSION BURNER  

E-print Network

rank, particle size, heat of combustion, porosity, and otherheat transfer from high temperature product gases or the combustionheat loss, it is not possible to burn coal samples in air, but oxygen enrichment is required to sustain combustion.

Chin, W.K.

2010-01-01

24

Taguchi methods applied to oxygen-enriched diesel engine experiments  

SciTech Connect

This paper describes a test series conducted on a six-cylinder diesel engine to study the impacts of controlled factors (i.e., oxygen content of the combustion air, water content of the fuel, fuel rate, and fuel-injection timing) on engine emissions using Taguchi methods. Three levels of each factor were used in the tests. Only the main effects of the factors were examined; no attempt was made to analyze the interactions among the factors. It was found that, as in the case of the single-cylinder engine tests, oxygen in the combustion air was very effective in reducing particulate and smoke emissions. Increases in NO{sub x} due to the oxygen enrichment observed in the single-cylinder tests also occurred in the present six-cylinder tests. Water in the emulsified fuel was found to be much less effective in decreasing NO{sub x} emissions for the six-cylinder engine than it was for the single-cylinder engine.

Marr, W.W.; Sekar, R.R.; Cole, R.L.; Marciniak, T.J. [Argonne National Lab., IL (United States); Longman, D.E. [Autoresearch Labs., Inc., Chicago, IL (United States)

1992-12-01

25

Taguchi methods applied to oxygen-enriched diesel engine experiments  

SciTech Connect

This paper describes a test series conducted on a six-cylinder diesel engine to study the impacts of controlled factors (i.e., oxygen content of the combustion air, water content of the fuel, fuel rate, and fuel-injection timing) on engine emissions using Taguchi methods. Three levels of each factor were used in the tests. Only the main effects of the factors were examined; no attempt was made to analyze the interactions among the factors. It was found that, as in the case of the single-cylinder engine tests, oxygen in the combustion air was very effective in reducing particulate and smoke emissions. Increases in NO[sub x] due to the oxygen enrichment observed in the single-cylinder tests also occurred in the present six-cylinder tests. Water in the emulsified fuel was found to be much less effective in decreasing NO[sub x] emissions for the six-cylinder engine than it was for the single-cylinder engine.

Marr, W.W.; Sekar, R.R.; Cole, R.L.; Marciniak, T.J. (Argonne National Lab., IL (United States)); Longman, D.E. (Autoresearch Labs., Inc., Chicago, IL (United States))

1992-01-01

26

Evaluation of oxygen-enrichment system for alternative fuel vehicles  

SciTech Connect

This report presents results on the reduction in exhaust emissions achieved by using oxygen-enriched intake air on a flexible fuel vehicle (FFV) that used Indolene and M85 as test fuels. The standard federal test procedure (FTP) and the US Environmental Protection Agency`s (EPA`s) off-cycle (REP05) test were followed. The report also provides a review of literature on the oxygen membrane device and design considerations. It presents information on the sources and contributions of cold-phase emissions to the overall exhaust emissions from light-duty vehicles (LDVs) and on the various emission standards and present-day control technologies under consideration. The effects of oxygen-enriched intake air on FTP and off-cycle emissions are discussed on the basis of test results. Conclusions are drawn from the results and discussion, and different approaches for the practical application of this technology in LDVs are recommended.

Poola, R.B.; Sekar, R.R.; Ng, H.K.

1995-12-01

27

Demonstration of oxygen-enriched air staging at Owens-Brockway glass containers. Final technical report for the period April 1, 1995--February 28, 1997  

SciTech Connect

The overall objective of this program was to demonstrate the use of a previously developed combustion modification technology to reduce NO{sub x} emissions from sideport regenerative container glass melters. Specific objectives were to: acquire baseline operating data on the host sideport furnace, evaluate secondary oxidant injection strategies based on earlier endport furnace results and through modeling of a single port pair, retrofit and test one port pair (the test furnace has six port pairs) with a flexible OEAS system, and select the optimal system configuration, use the results from tests with one port pair to design, retrofit, and test OEAS on the entire furnace (six port pairs), and analyze test results, prepare report, and finalize the business plan to commercialize OEAS for sideport furnaces.

Rue, D.; Abbasi, H.

1997-10-01

28

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

NASA Astrophysics Data System (ADS)

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.

Koenig, Dieter

1994-01-01

29

AIR EMISSIONS FROM SCRAP TIRE COMBUSTION  

EPA Science Inventory

The report discusses air emissions from two types of scrap tire combustion: uncontrolled and controlled. Uncontrolled sources are open tire fires, which produce many unhealthful products of incomplete combustion and release them directly into the atmosphere. Controlled combustion...

30

Fire extinguishment in oxygen enriched atmospheres  

NASA Technical Reports Server (NTRS)

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.

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

1973-01-01

31

Reduction of combustion by-products in WTE plants: O2 enrichment of underfire air in the MARTIN SYNCOM process.  

PubMed

The SYNCOM process involves oxygen enrichment of underfire air, recirculation of flue gas and a combustion control system using infrared thermography of the waste layer on the grate. At the demonstration plant in Coburg, operational reliability and plant availability using SYNCOM could be proven under real disposal conditions with a waste throughput of 7 t/h. Oxygen enrichment of the underfire air promotes the destruction of pollutants due to the high oxygen partial pressures and temperatures. This is then reflected in very low residual amounts of organic combustion by-products in the bottom ash and flue gas from the SYNCOM unit. The flue gas concentrations of organic pollutants are reduced, as compared with conventional operation, by over 35% (for CO, total hydrocarbons and PCDD/F) at the boiler outlet. As the flue gas flow is reduced by oxygen enrichment and flue gas recirculation, the resulting reduction in terms of kg of pollutant per Mg of waste is even higher. In the bottom ash, the level of organic residues is reduced, by 45% in the case of loss on ignition and by 55% in the case of TOC and dioxins (I-TE of PCDD/F). This is due to the higher oxygen partial pressures and the fuel bed temperature which is increased by 135 to 1200 degrees C. Other important features of the process include more intense sintering and thus improved immobilization of the bottom ash, as well as reduced flue gas and fly ash flows. PMID:11219678

Gohlke, O; Busch, M

2001-01-01

32

Properties of air and combustion products of fuel with air  

NASA Technical Reports Server (NTRS)

Thermodynamic and transport properties have been calculated for air, the combustion products of natural gas and air, and combustion products of ASTM-A-1 jet fuel and air. Properties calculated include: ratio of specific heats, molecular weight, viscosity, specific heat, thermal conductivity, Prandtl number, and enthalpy.

Poferl, D. J.; Svehla, R. A.

1975-01-01

33

Turbulent Methane-Air Combustion  

NASA Technical Reports Server (NTRS)

This study is aimed at enhancing the understanding of turbulent premixed methane-air combustion. Such understanding is essential since: (1) many industries are now pursuing lighter hydrocarbon alternative fuels and the use of premixed flames to reduce pollutant emissions, and (2) the characteristic dimensions and flow rates of most industrial combustors are often large for flows to be turbulent. The specific objectives of the study are: (1) to establish the effects of process variables (e.g., flow rate, fuel/air ratio, chlorinated hydro-carbons, and pressure) on the emissions and flow structure (velocity distribution, streamlines, vorticity and flame shape), and (2) to develop a mechanistic model to explain the observed trends. This includes the acquisition of Dantec FlowMap Particle Image Velocimeter. The design and fabrication of the premixed burner has also been completed. The study is now at the stage of testing of equipment and analytical instruments. The presentation will give details on the tasks completed and on the current and future plans. The project is progressing well and all activities are on schedule. The outlook for the success of the project is bright.

Yaboah, Yaw D.; Njokwe, Anny; James, LaShanda

1996-01-01

34

A simplified method for determining heat of combustion of natural gas  

NASA Technical Reports Server (NTRS)

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.

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

1987-01-01

35

Combustion air can become a problem  

SciTech Connect

Improper air combustion in a well-sealed house can result in an inadequate supply of oxygen and dangerous or fatal carbon monoxide levels. An opening for outside combustion air can prevent ''air starvation'' and if properly located and sized, can save energy by improving the furnace efficiency. This opening will also keep cold outside air from entering when the furnace is not in use, and prevent a blockage when in use, if properly designed. Possible indicators of inadequate combustion air in oil-fueled homes are: chimney smoke is black-colored, fuel smell in house, soot accumulation, popping, banging, or late ignition in the furnace. In natural gas-fueled homes: excessive moisture collecting on windows and walls, frequent headaches, burning feeling in nose and eyes. (JMT)

Not Available

1982-01-01

36

Combustion engine. [for air pollution control  

NASA Technical Reports Server (NTRS)

An arrangement for an internal combustion engine is provided in which one or more of the cylinders of the engine are used for generating hydrogen rich gases from hydrocarbon fuels, which gases are then mixed with air and injected into the remaining cylinders to be used as fuel. When heavy load conditions are encountered, hydrocarbon fuel may be mixed with the hydrogen rich gases and air and the mixture is then injected into the remaining cylinders as fuel.

Houseman, J. (inventor)

1977-01-01

37

System for heat recovery for combustion machine including compressor for combustion air  

Microsoft Academic Search

A system for waste heat recovery is disclosed. It comprises a combustion machine with a compressor for the combustion air and means like a heat exchanger and\\/or a recirculation duct, to transfer heat, contained in the combustion gases after their expansion in the machine, to the combustion air flow before its entry into the compressor. Water is introduced into the

Collet

1984-01-01

38

Fixed-bed performance for production of oxygen-enriched carbon dioxide stream by perovskite-type ceramic sorbent  

Microsoft Academic Search

This paper reports on an experimental study on production of oxygen-enriched carbon dioxide stream by a fixed-bed packed with a perovskite-type ceramic sorbent La0.1Sr0.9Co0.5Fe0.5O3??, which can adsorb oxygen from air. Oxygen-enriched carbon dioxide stream is produced by passing carbon dioxide into the fixed-bed saturated with oxygen. Fixed-bed experiments were performed to study the oxygen separation performance of this sorbent. The

Qing Yang; Jerry Y. S. Lin

2006-01-01

39

Furnace Controls Using High Temperature Preheated Combustion Air  

E-print Network

FURNACE CONTROLS USING HIGH TEMPERATURE PREHEATED COMBUSTION AIR Jeffrey M. Gonzalez Wilfred J. Rebello GTE Products Corporation PAR Enterprises, Inc. Towanda, Pennsylvania Fairfax, Virginia ABSTRACT GTE Products Corporation (Towanda... available ratio control apparatus. Various control sys (I) was the development of a different way of looking at combustion. As preheated combustion air temperatures increase, excess air Industrial furnaces generally utilize air as the basic source...

Gonzales, J. M.; Rebello, W. J.

1981-01-01

40

Pulverised Coal Combustion Under Transient Cloud Conditions in a Drop Tube Furnace  

Microsoft Academic Search

A low volatile coal was burned with oxygen-enriched air in a drop tube furnace at 1223 and 1523 K, either as single particles or as small batches added as a pulse. The particle temperatures and burnout times at the two furnace temperatures were recorded for each test. The ignition \\/ combustion processes were recorded by pyrometer and video camera. The

B. R. STANMORE; Y.-C. CHOI; R. GADIOU; O. CHARON; P. GILOT

2000-01-01

41

Emission Controls Using Different Temperatures of Combustion Air  

PubMed Central

The effort of many manufacturers of heat sources is to achieve the maximum efficiency of energy transformation chemically bound in the fuel to heat. Therefore, it is necessary to streamline the combustion process and minimize the formation of emission during combustion. The paper presents an analysis of the combustion air temperature to the heat performance and emission parameters of burning biomass. In the second part of the paper the impact of different dendromass on formation of emissions in small heat source is evaluated. The measured results show that the regulation of the temperature of the combustion air has an effect on concentration of emissions from the combustion of biomass. PMID:24971376

Holubcik, Michal; Papucik, Stefan

2014-01-01

42

Emission controls using different temperatures of combustion air.  

PubMed

The effort of many manufacturers of heat sources is to achieve the maximum efficiency of energy transformation chemically bound in the fuel to heat. Therefore, it is necessary to streamline the combustion process and minimize the formation of emission during combustion. The paper presents an analysis of the combustion air temperature to the heat performance and emission parameters of burning biomass. In the second part of the paper the impact of different dendromass on formation of emissions in small heat source is evaluated. The measured results show that the regulation of the temperature of the combustion air has an effect on concentration of emissions from the combustion of biomass. PMID:24971376

Nosek, Radovan; Holub?ík, Michal; Papu?ík, Štefan

2014-01-01

43

Pulse combustion forced-air heating  

SciTech Connect

During the mid-to-late 1970's, the producers and distributors of natural gas fuels were predicting, based on known reserves, that the United States would have serious shortages of this resource by the late 1980's and critical shortages by the late 1990's. At the same time, estimates on the production costs for new natural gas were skyrocketing. There was every indication that in the future natural gas demand could exceed supplies and costs would increase dramatically. These circumstances created a serious need for engineering innovation to conserve this dwindling natural resource. The development and commercialization of one such engineering innovation, the pulse combustion furnace, is discussed. This new warm air heating system will significantly reduce the amount of natural gas required to perform a given space heating function when compared to similar equipment generally available for the same function today.

Stephens, R.L. Jr.

1983-07-01

44

Proceedings of air toxic reduction and combustion modeling  

SciTech Connect

This book contains proceedings of Air Toxic Reduction and Combustion Modelling. Topics include modeling of furnaces, burners, combustors, gaseous flames, spray combustion, coal and coal slurry combustion. Both fundamental and applied studies in the area of pollution control, including NO[sub x], and efficiency are of interest. Systems of special interest included furnaces and boilers, gas turbine combustion, internal combustion engines and other power generation systems. Fundamental and applied, as well as numerical and experimental studies were of interest, with emphasis on the evolution of toxic metals and the modeling of rotary-kiln and fluidized-bed incinerators.

Gupta, A.K. (Univ. of Maryland, MD (United States)); Presser, G. (National Inst. of Standards and Technology (United States)); Axelbaum, R.L. (Washington Univ. (United States))

1992-01-01

45

Asthma aggravation, combustion, and stagnant air  

PubMed Central

BACKGROUND—The relationship between current concentrations of ambient air pollution and adverse health effects is controversial. We report a meteorological index of air stagnation that is associated with daily visits to the emergency department for asthma in two urban areas.?METHODS—Data on daily values of a stagnation persistence index and visits to the emergency department for asthma were collected for approximately two years in Spokane, Washington, USA and for 15months in Seattle, Washington, USA. The stagnation persistence index represents the number of hours during the 24 hour day when surface wind speeds are less than the annual hourly median value, an index readily available for most urban areas. Associations between the daily stagnation persistence index and daily emergency department visits for asthma were tested using a generalised additive Poisson regression model. A factor analysis of particulate matter (PM2.5) composition was performed to identify the pollutants associated with increased asthma visits.?RESULTS—The relative rate of the association between a visit to the emergency department for asthma and the stagnation persistence index was 1. 12 (95% CI 1.05 to 1.19) in Spokane and 1.21 (95% CI 1.09 to 1.35) in Seattle for an increase of 11 and 10 hours, respectively, of low wind speed in a given day. The stagnation persistence index was only correlated with one set of factor loadings; that cluster included the stagnation persistence index, carbon monoxide, and organic/elemental carbon.?CONCLUSION—Increased air stagnation was shown to be a surrogate for accumulation of the products of incomplete combustion, including carbon monoxide and fine particulate levels of organic and elemental carbon, and was more strongly associated with asthma aggravation than any one of the measured pollutants.?? PMID:10817794

Norris, G.; Larson, T.; Koenig, J.; Claiborn, C.; Sheppard, L.; Finn, D.

2000-01-01

46

Basic Considerations in the Combustion of Hydrocarbon Fuels with Air  

NASA Technical Reports Server (NTRS)

Basic combustion research is collected, collated, and interpreted as it applies to flight propulsion. The following fundamental processes are treated in separate chapters: atomization and evaporation of liquid fuels, flow and mixing processes in combustion chambers, ignition and flammability of hydrocarbon fuels, laminar flame propagation, turbulent flames, flame stabilization, diffusion flames, oscillations in combustors, and smoke and coke formation in the combustion of hydrocarbon-air mixtures. Theoretical background, basic experimental data, and practical significance to flight propulsion are presented.

Barnett, Henry C; Hibbard, Robert R

1957-01-01

47

Air flow measuring device for internal combustion engines  

Microsoft Academic Search

An air\\/fuel ratio compensating device is provided for association with an internal combustion engine having a fuel control valve, air suction pipe means and pedal accelerator means , the compensating device including an area flow metal system made up of a flow detection valve positioned upstream in the air suction pipe means and operatively associated with the fuel control valve,

K. Kimata; T. Nakazeki; Y. Yasuda

1980-01-01

48

Air flow measuring device for internal combustion engines  

Microsoft Academic Search

An air\\/fuel ratio compensating device is provided for association with an internal combustion engine having a fuel control valve, air suction pipe means and pedal accelerator means, the compensating device including an area flow metal system made up of a flow detection valve positioned upstream in the air suction pipe means and operatively associated with the fuel control valve, a

K. Kimata; T. Nakazeki; Y. Yasuda

1983-01-01

49

AIR EMISSIONS FROM COMBUSTION OF SOLVENT REFINED COAL  

EPA Science Inventory

The report gives details of a Solvent Refined Coal (SRC) combustion test at Georgia Power Company's Plant Mitchell, March, May, and June 1977. Flue gas samples were collected for modified EPA Level 1 analysis; analytical results are reported. Air emissions from the combustion of ...

50

Influence of residential wood combustion on local air quality.  

PubMed

The importance of wood combustion to local air quality was estimated by measuring different air pollutants and conducting chemical mass balance modelling. PM10, PM2.5, PAHs and VOC concentrations in ambient air were measured in a typical Finnish residential area. Measurements were conducted in January-March 2006. For some compounds, wood combustion was clearly the main local source at this site. The effect of wood combustion was more clearly seen for organic compounds than for fine particle mass. For fine particles, background concentrations dominated. However, very high, short-lived concentration peaks were detected, when the wind direction and other weather conditions were favourable. For organic compounds, the effect of wood combustion was seen in diurnal and in two-week average concentrations. PAH-concentrations were often several times higher at the residential area than in the background. Benzene concentrations showed similar diurnal pattern as the use of wood and benzene/toluene ratios indicated that wood combustion is the most important source. A chemical mass balance model was used for studying the effect of wood combustion on the measured concentrations of VOCs. Model results showed that the main local sources for VOCs at Kurkimäki are wood combustion and traffic. Wood combustion was clearly the most important source for many compounds (e.g., benzene). PMID:18272205

Hellén, H; Hakola, H; Haaparanta, S; Pietarila, H; Kauhaniemi, M

2008-04-15

51

Adaptive air\\/fuel ratio controller for internal combustion engine  

Microsoft Academic Search

An air\\/fuel ratio controller for an internal combustion engine including two memories each having numbers stored at locations addressed by engine operating points with the locations addressed by the engine operating points being updated during closed loop operation in accord with the value of a closed loop adjustment of the air\\/fuel ratio. Each memory location in the first memory is

A. F. Chiesa; D. G. Evans; J. R. Norford; J. A. Zahorchak

1982-01-01

52

Removal of trichlorobenzene using 'oxygen-enriched' highly active absorbent.  

PubMed

Fly ash, industry lime and an additive, Ca(ClO2)2 (C) were used to prepare the 'oxygen-enriched' highly active absorbent (HAA). The influencing factors for removal of 1,2,4-trichlorobenzene (TCB) using this absorbent such as reaction temperature, simulating gas flow rate, oxygen content, etc. were studied in a self-designed reactor. The optimum experimental conditions of removing 1,2,4-TCB are that the content of an oxidizing additive in the absorbent is 3% (wt), simulating gas flow rate is 100 mL/min, reaction temperature is 250 degrees C, and the content of oxygen in simulating gas is 6%. The maximum removal efficiency is 81.71% in 10 mins. The absorption capacity of the absorbent is 0.000111 g/g. The reaction products were determined by gas chromatograph/mass spectrometer (GC/ MS), 2,6-Bis-[1,1-Dimethylethyl]-4-methyl-Phenol is considered to be the major intermediate product. The reaction route was revealed. PMID:21473266

Zhao, Yi; He, Peng; Zhang, Yu-Hai; Ma, Shuangchen

2011-01-01

53

BIBLIOGRAPHY ON INTERNAL COMBUSTION ENGINES 1. F. Obert, Internal Combustion Engines and Air Pollution, Intext Educational Publishers, 1973  

E-print Network

BIBLIOGRAPHY ON INTERNAL COMBUSTION ENGINES 1. F. Obert, Internal Combustion Engines and Air, The Internal Combustion Engine, International Textbook Company, 1961. (A basic text now out of print and somewhat dated.) 3. C.F. Taylor, The Internal Combustion Engine in Theory and Practice. Volumes I and II, M

Goldwasser, Shafi

54

Catalytic Igniter to Support Combustion of Ethanol-Water\\/Air Mixtures in Internal Combustion Engines  

Microsoft Academic Search

Lean ethanol-water\\/air mixtures have potential for reducing NOx and CO emissions in internal combustion engines. Igniting such mixtures is not possible with conventional ignition sources. An improved catalytic ignition source is being developed to aid in the combustion of aqueous ethanol. The operating principle is homogeneous charge compression ignition in a catalytic pre-chamber, followed by torch ignition of the main

Dan Cordon; Eric Clarke; Steven Beyerlein; Judi Steciak

55

Closed loop air cooling system for combustion turbines  

DOEpatents

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.

Huber, D.J.; Briesch, M.S.

1998-07-21

56

COMBUSTION CONTROL OF TRACE ORGANIC AIR POLLUTANTS FROM MUNICIPAL WASTE COMBUSTORS  

EPA Science Inventory

The US Environmental Protection Agency (EPA) is considering the use of combustion techniques for controlling air emissions of chlorinated dioxins, chlorinated furans, and other trace organics from municipal waste combustion (MWC) facilities. Recommendations for good combustion pr...

57

Indoor air quality environmental information handbook: Combustion sources  

SciTech Connect

This environmental information handbook was prepared to assist both the non-technical reader (i.e., homeowner) and technical persons (such as researchers, policy analysts, and builders/designers) in understanding the current state of knowledge regarding combustion sources of indoor air pollution. Quantitative and descriptive data addressing the emissions, indoor concentrations, factors influencing indoor concentrations, and health effects of combustion-generated pollutants are provided. In addition, a review of the models, controls, and standards applicable to indoor air pollution from combustion sources is presented. The emphasis is on the residential environment. The data presented here have been compiled from government and privately-funded research results, conference proceedings, technical journals, and recent publications. It is intended to provide the technical reader with a comprehensive overview and reference source on the major indoor air quality aspects relating to indoor combustion activities, including tobacco smoking. In addition, techniques for determining potential concentrations of pollutants in residential settings are presented. This is an update of a 1985 study documenting the state of knowledge of combustion-generated pollutants in the indoor environment. 191 refs., 51 figs., 71 tabs.

Not Available

1990-06-01

58

Combustion performance evaluation of air staging of palm oil blends.  

PubMed

The problems of global warming and the unstable price of petroleum oils have led to a race to develop environmentally friendly biofuels, such as palm oil or ethanol derived from corn and sugar cane. Biofuels are a potential replacement for fossil fuel, since they are renewable and environmentally friendly. This paper evaluates the combustion performance and emission characteristics of Refined, Bleached, and Deodorized Palm Oil (RBDPO)/diesel blends B5, B10, B15, B20, and B25 by volume, using an industrial oil burner with and without secondary air. Wall temperature profiles along the combustion chamber axis were measured using a series of thermocouples fitted axially on the combustion chamber wall, and emissions released were measured using a gas analyzer. The results show that RBDPO blend B25 produced the maximum emission reduction of 56.9% of CO, 74.7% of NOx, 68.5% of SO(2), and 77.5% of UHC compared to petroleum diesel, while air staging (secondary air) in most cases reduces the emissions further. However, increasing concentrations of RBDPO in the blends also reduced the energy released from the combustion. The maximum wall temperature reduction was 62.7% for B25 at the exit of the combustion chamber. PMID:22296110

Mohd Jaafar, Mohammad Nazri; Eldrainy, Yehia A; Mat Ali, Muhammad Faiser; Wan Omar, W Z; Mohd Hizam, Mohd Faizi Arif

2012-02-21

59

Combustion Air Preheat on Steam Cracker Furnaces  

E-print Network

Beginning in 1978, Exxon has started up nine large new steam cracking furnaces with various levels of air preheat, and has seven more under construction. Sources of heat have included process streams, flue gas and gas turbine exhaust. Several...

Kenney, W. F.

1983-01-01

60

REFINERY PROCESS HEATER NOX CONTROL BY STAGED COMBUSTION AIR LANCES  

EPA Science Inventory

The paper gives results of tests of a natural-draft petroleum-refinery crude-oil process heater, modified to reduce oxides of nitrogen (NOx) emissions by installing staged-combustion air lances. Baseline nitric oxide (NO) emissions firing refinery gas before modification were mea...

61

Effect of Combustion Air Preheat on a Forged Furnace Productivity  

E-print Network

A basic thermal analysis of a gas fired forge furnace can determine the fuel savings from exhaust energy recovery/combustion air preheat on a furnace operating at a single condition, for example, high fire. What this analysis is not able...

Ward, M. E.; Bohn, J.; Davis, S. R.; Knowles, D.

1984-01-01

62

Oxygen Enrichment in the Process and Chemical Industries  

E-print Network

an air oxidation step (Table 1). Some Organic Intermediates Produced by Air Oxidation: ? Adipic Acid ? Acetaldehyde ? Acetic Acid ? Acrylonitrile ? Acrylic Acid ? Acetone ? Ethylene Oxide ? Formaldehyde ? Maleic Anhydride ? Phenol... an air oxidation step (Table 1). Some Organic Intermediates Produced by Air Oxidation: ? Adipic Acid ? Acetaldehyde ? Acetic Acid ? Acrylonitrile ? Acrylic Acid ? Acetone ? Ethylene Oxide ? Formaldehyde ? Maleic Anhydride ? Phenol...

Milne, R. T.

1984-01-01

63

Particulate emissions from combustion of biomass in conventional combustion (air) and oxy-combustion conditions  

NASA Astrophysics Data System (ADS)

Oxy-fuel combustion is a viable technology for new and existing coal-fired power plants, as it facilitates carbon capture and thereby, can reduce carbon dioxide emissions. The use of biomass as an energy source is another popular strategy to reduce carbon dioxide emissions as they are considered nearly carbon dioxide neutral. If the use of biomass is combined with oxy-fuel combustion, negative net emissions of carbon dioxide are possible. This work examined the particulate emissions from combustion of pulverized biomass residues burning in either conventional or oxy-fuel environments. Combustion of three biomasses (olive residue, corn residue, and torrefied pine sawdust) occurred in a laboratory-scale laminar-flow drop tube furnace (DTF) heated to 1400 K. The O2 mole fraction was increased from 20% to 60% in N2 environments while a range of 30% to 60% O2 mole fractions were used in CO2 environments to represent plausible dry oxy-fuel combustion conditions. Submicron particulate matter (PM1) emission yields of all three fuels were typically lower in O2/CO2 environments than in O2/N2 environments. When the oxygen mole fraction was increased, the PM1 yields typically increased. The mass fractions of submicron particulate matter (PM1/PM18) collected from biomass combustion were higher than those of coal combustion. PM 1 constituted approximately 50 wt% of the collected ash particles in PM18 in each environment, whereas the corresponding submicron emissions from coal constituted approximately 20 wt%. Changing the background gas had little effect on the chemical composition of the PM1 particles. Unlike the submicron particles collected from coal which contained high amounts of silicon and aluminum, high amounts of alkalis (potassium, calcium, and sodium) and chlorine were the major elements observed in PM1 from the biomasses. In addition, phosphorous and sulfur also existed in high amounts in PM1 of corn residue. Super-micron particles (PM1-18) yields exhibited no clear trend when the background gas was changed or when the oxygen mole fraction was increased. The composition of these particles reflected the bulk ash composition of the parent fuels. Olive residue resulted in by far the largest particulate yields, while torrefied pine sawdust had the lowest. The yields of these two biomasses were analogous with the ash contents of the parent fuels. The particulate yields of corn residue, however, were lower than expected when compared to the parent fuel's ash content. This was attributed to the high phosphorous and sulfur contents of this fuel which might have increased its deposition tendencies in the laboratory furnace.

Ruscio, Amanda Deanne

64

Fuel-Air Mixing and Combustion in Scramjets. Chapter 6  

NASA Technical Reports Server (NTRS)

At flight speeds, the residence time for atmospheric air ingested into a scramjet inlet and exiting from the engine nozzle is on the order of a millisecond. Therefore, fuel injected into the air must efficiently mix within tens of microseconds and react to release its energy in the combustor. The overall combustion process should be mixing controlled to provide a stable operating environment; in reality, however, combustion in the upstream portion of the combustor, particularly at higher Mach numbers, is kinetically controlled where ignition delay times are on the same order as the fluid scale. Both mixing and combustion time scales must be considered in a detailed study of mixing and reaction in a scramjet to understand the flow processes and to ultimately achieve a successful design. Although the geometric configuration of a scramjet is relatively simple compared to a turbomachinery design, the flow physics associated with the simultaneous injection of fuel from multiple injector configurations, and the mixing and combustion of that fuel downstream of the injectors is still quite complex. For this reason, many researchers have considered the more tractable problem of a spatially developing, primarily supersonic, chemically reacting mixing layer or jet that relaxes only the complexities introduced by engine geometry. All of the difficulties introduced by the fluid mechanics, combustion chemistry, and interactions between these phenomena can be retained in the reacting mixing layer, making it an ideal problem for the detailed study of supersonic reacting flow in a scramjet. With a good understanding of the physics of the scramjet internal flowfield, the designer can then return to the actual scramjet geometry with this knowledge and apply engineering design tools that more properly account for the complex physics. This approach will guide the discussion in the remainder of this section.

Drummond, J. Philip; Diskin, Glenn S.; Cutler, Andrew D.

2006-01-01

65

Species measurements in a hypersonic, hydrogen-air, combustion wake  

SciTech Connect

A continuously sampling, time-of-flight mass spectrometer has been used to measure relative species concentrations in a two-dimensional, hydrogen-air combustion wake at mainstream Mach numbers exceeding 5. The experiments, in a free piston shock tunnel, yielded distributions of hydrogen, oxygen, nitrogen, water, and nitric oxide at stagnation enthalpies ranging from 5.6 MJ/kg to 12.2 MJ/kg and at a distance of approximately 100s times the thickness of the initial hydrogen jet. The amount of hydrogen mixed in stoichiometric proportions was approximately independent of the stagnation enthalpy, despite the fact that the proportion of hydrogen in the wake was increased with stagnation enthalpy. Roughly 50% of the mixed hydrogen underwent combustion at the highest enthalpy. The proportion of hydrogen reacting to water could be approximately predicted using reaction rates based on mainstream temperatures.

Skinner, K.A.; Stalker, R.J. [Univ. of Queensland, Brisbane, Queensland (Australia)] [Univ. of Queensland, Brisbane, Queensland (Australia)

1996-09-01

66

Combustion of stratified hydrogen-air mixtures in the 10.7 m 3 combustion test facility cylinder  

Microsoft Academic Search

This paper presents preliminary results from hydrogen concentration gradient combustion experiments in a 10.7 m3 cylinder. These gradients, also referred to as stratified mixtures, were formed from dry mixtures of hydrogen and air at atmospheric temperature. Combustion pressures, burn fractions and flame speeds in concentration gradients were compared with combustion of well-mixed gases containing equivalent amounts of hydrogen. The studied

D. R. Whitehouse; D. R. Greig; G. W. Koroll

1996-01-01

67

A new approach to oxygen enriched high temperature blast generation  

SciTech Connect

When increasing fuel injection in a blast furnace in order to reduce coke consumption and/or to increase production, the blast furnace operator tries to keep similar raceway conditions, for instance, an equivalent flame temperature. To compensate for the cooling effect due to the higher injection rate, two solutions can be selected or combined: to raise the temperature of the blast and/or to increase the level of oxygen in the blast. Whatever the choice, the Blast Furnace manager will certainly try to reduce the resulting investment and operating costs to a minimum. Air Liquide and Kvaerner Davy are trying to provide a new way to address these needs by offering a new technology for blast heating. A higher blast temperature will not only allow a higher fuel injection at tuyere level, a lower coke consumption, but also a lower oxygen consumption. Air Liquide and Kvaerner Davy are now able to offer a new heat regenerator with major advantages over conventional stoves. This new device can be used as a permanent substitute for a stove, or as a temporary one during repair, or stove improvement. It can also be added to an existing set of stoves to increase the average blast temperature.

Queille, P.H.; Macauley, D.

1996-12-31

68

RESEARCH AREA -- MUNICIPAL WASTE COMBUSTION (AIR POLLUTION TECHNOLOGY BRANCH, AIR POLLUTION PREVENTION AND CONTROL DIVISION, NRMRL)  

EPA Science Inventory

The municipal waste combustion (MWC) program supports the development of revised rules for air pollutant emissions from the MWC source category. Basic research is performed on MWC pollutant formation and control mechanisms for acid gas, trace organic, and trace metal emissions. T...

69

Combustion Air Preheat Should Be More Than Simply Recycling Energy  

E-print Network

pair of equa tions which, when used together, explains why combus tion air preheat is more than simply recycling energy. Reference {I} shows that, by making certain assump tions, 0.173 [G~ 4 G~~ 4] (1)+ For fired heaters, TT the average...} shows the amount of heat absorbed in the radiant zone must equal the heat given up by the flue gas in dropping from the adiabatic flame temperature, T F , of the combustion process to the "bridgewall" temperature, T R . - 4 WTFe pf I W C (2) 1 c...

Grantom, R. L.

1980-01-01

70

In-Depth Experimental Study of Solid-Waste Destruction by High Temperature Air Combustion  

Microsoft Academic Search

The objective of this article is to investigate the application of high temperature air combustion in thermal destruction of solid waste. The secondary air was preheated at different temperatures and burned with low calorific value and high content of diluted inert gas released from solid waste. It was discovered that the combustion with the higher preheated secondary air temperature had

P. Suvarnakuta; S. Patumsawad; S. Kerdsuwan

2009-01-01

71

Apparatus for controlling inlet air flow in a turbocharged internal combustion engine  

Microsoft Academic Search

This patent describes an apparatus for controlling inlet air flow in an internal combustion engine having a turbo-supercharger. The turbo-supercharge having a turbine driven by a pressure of an exhaust gas and an air compressor actuated by the turbine and connected to a combustion chamber of the engine through at least two intake passages so that inlet air compressed thereby

Mizutani

1988-01-01

72

Adaptive air/fuel ratio controller for internal combustion engine  

SciTech Connect

An air/fuel ratio controller for an internal combustion engine including two memories each having numbers stored at locations addressed by engine operating points with the locations addressed by the engine operating points being updated during closed loop operation in accord with the value of a closed loop adjustment of the air/fuel ratio. Each memory location in the first memory is updated during operation of the engine at the corresponding operating point in accord with an update time constant having a value so that the number stored tracks adjustment value producing the predetermined desired closed loop air/fuel ratio during varying values of engine operating parameters. Each memory location in the second memory is updated during operation of the engine at the corresponding operating point in accord with an update time constant having a value so that the number stored is the average of the values producing the predetermined closed loop air/fuel ratio during varying values of engine operating parameters. The first memory is used during closed loop operation to preset the closed loop adjustment at least when the engine first operates at an operating point and the second memory is utilized during open loop operation to adjust the air/fuel ratio by an amount determined at least in part by the number stored in the second memory at locations addressed by the engine operating point.

Chiesa, A.F.; Evans, D.G.; Norford, J.R.; Zahorchak, J.A.

1982-01-12

73

Experimental and Numerical Studies on Methane\\/Air Combustion in a Micro Swiss-Roll Combustor  

Microsoft Academic Search

To understand effects of an air groove on working characteristics of micro Swiss-roll combustors, combustion of premixed CH4\\/air is conducted in 2 micro Swiss-roll combustors, one with an air groove and the other without. Experimental results show that stable combustion of premixed CH4\\/air in 2 combustors can be achieved and the flame is kept in combustor's center. An air groove

Junwei Li; Beijing Zhong; Ningfei Wang; Zhijun Wei

2010-01-01

74

Future Directions of Supersonic Combustion Research: Air Force/NASA Workshop on Supersonic Combustion  

NASA Technical Reports Server (NTRS)

The Air Force Office of Scientific Research, the Air Force Wright Laboratory Aero Propulsion and Power Directorate, and the NASA Langley Research Center held a joint supersonic combustion workshop on 14-16 May 1996. The intent of this meeting was to: (1) examine the current state-of-the-art in hydrocarbon and/or hydrogen fueled scramjet research; (2) define the future direction and needs of basic research in support of scramjet technology; and (3) when appropriate, help transition basic research findings to solve the needs of developmental engineering programs in the area of supersonic combustion and fuels. A series of topical sessions were planned. Opening presentations were designed to focus and encourage group discussion and scientific exchange. The last half-day of the workshop was set aside for group discussion of the issues that were raised during the meeting for defining future research opportunities and directions. The following text attempts to summarize the discussions that took place at the workshop.

Tishkoff, Julian M.; Drummond, J. Philip; Edwards, Tim; Nejad, Abdollah S.

1997-01-01

75

Effect of combustion chamber shape on air flow field in a D. I. diesel engine  

Microsoft Academic Search

The behaviour of two combustion chambers, a toroidal and a turbulent one, has been compared. The engine performance in terms of imep and exhaust emissions were measured. Laser Doppler Anemometry technique was used to characterize the fluids dynamic aspect of combustion system. The axial asymmetry introduced in combustion chamber shape causes strong differences in the air flow field at the

C. Bertoli; F. E. Corcione; G. Police; G. Valentino

1987-01-01

76

Considerations of Air Flow in Combustion Chambers of High-Speed Compression-Ignition Engines  

NASA Technical Reports Server (NTRS)

The air flow in combustion chambers is divided into three fundamental classes - induced, forced, and residual. A generalized resume is given of the present status of air flow investigations and of the work done at this and other laboratories to determine the direction and velocity of air movement in auxiliary and integral combustion chambers. The effects of air flow on engine performance are mentioned to show that although air flow improves the combustion efficiency, considerable induction, friction, and thermal losses must be guarded against.

Spanogle, J A; Moore, C S

1932-01-01

77

Comparative kinetic calculations of turbulent combustion of air mixtures of hydrogen and methane  

Microsoft Academic Search

The authors compare several mathematical models describing the combustion kinetics of hydrogen-air and methane-air mixtures under conditions of turbulence in the flame propagation region. The process considered is based on homogeneous combustion with jet stabilization of the flame. The participation of 18 elements and compounds in a total of 35 reactions occurring in both forward and reverse directions is tabulated.

V. Ya. Basevich; V. P. Volodin; S. M. Kogarko; N. I. Peregudov

1986-01-01

78

NUMERICAL ANALYSIS OF FLOW VELOCITY DISTRIBUTION IN HIGH TEMPERATURE AIR COMBUSTION FURNACE  

Microsoft Academic Search

The three-dimensional velocity distribution in a small scale high temperature air combustion furnace was numerically simulated with a developed CFD program. Three case for an isothermal flow configuration were predicted under the conditions of three different velocity ratios of fuel to air injection. The flow fields of iso- thermal calculations are compare to those of a combusting flow. It is

Li-Jun WANG; Zong-Shu ZOU; Jiu-ju CAI; Yu-Ling HAO

79

Identification of combustion losses and air flow control in power plants burning inhomogeneous fuels  

Microsoft Academic Search

Combustion air flow control has a strong effect on the efficiency of a power plant. When using homogeneous fuels such as oil and natural gas the control can be based on an assumption that certain volumetric or mass flow of the fuel needs always a certain air flow for complete combustion. But with inhomogeneous fuels and in multi-fuel boilers this

Kari Lehtomäki; Reijo Ramu

80

Investigation of Ignition and Combustion Processes of Diesel Engines Operating with Turbulence and Air-storage Chambers  

NASA Technical Reports Server (NTRS)

The flame photographs obtained with combustion-chamber models of engines operating respectively, with turbulence chamber and air-storage chambers or cells, provide an insight into the air and fuel movements that take place before and during combustion in the combustion chamber. The relation between air velocity, start of injection, and time of combustion was determined for the combustion process employing a turbulence chamber.

Petersen, Hans

1938-01-01

81

Intake air flow rate control system for an internal combustion engine of an automotive vehicle  

Microsoft Academic Search

Disclosed is an intake air flow rate control system for an internal combustion engine, including a means for detecting acceleration and deceleration of the vehicle and controlling the air flow rate in response to required air flow rate which is varied by acceleration and deceleration of the vehicle. The means temporarily operates to vary the air flow rate at the

Ikeuva

1983-01-01

82

Combustion Gas Turbine Power Enhancement by Refrigeration of Inlet Air  

E-print Network

Combustion gas turbines have gained widespread acceptance for mechanical drive and power generation applications. One key drawback of a combustion turbine is that its specific output and thermal efficiency vary quite significantly with variations...

Meher-Homji, C. B.; Mani, G.

1983-01-01

83

APTI (Air Pollution Training Institute) course 427: combustion evaluation, instructor's guide  

SciTech Connect

This Instructor's Guide is used in conjunction with Course No. 427, 'Combustion Evaluation' as applied to air pollution control situations. The teaching guide was prepared by the EPA Air Pollution Training Institute (APTI) to assist instructors in presenting course No. 427. The guide contains sections on the following topics: combustion fundamentals, fuel properties, combustion system design, pollutant emission calculations, combustion control, gas, oil, and burning, solid waste and wood burning, incineration of wastes, sewage sludge incineration, flame and catalytic incineration, waste gas flares, hazardous waste combustion, NOx control, improved combustion systems. Note: There is also a Student Workbook to be used for homework and in-class problem solving (EPA-450/2-80-064) and a Student Manual for reference and additional subject material (EPA-450/2-80-063).

Beard, J.T.; Iachetta, F.A.; Lilleleht, L.U.

1980-02-01

84

APTI (Air Pollution Training Institute) Course 427: combustion evaluation, student manual  

SciTech Connect

This Student Manual is used in conjunction with Course No. 427, 'Combustion Evaluation' as applied to air pollution control situations. This manual was prepared by the EPA Air Pollution Training Institute (APTI) to supplement the course lecture materials and to present detailed reference information on the following topics: combustion fundamentals, fuel properties, combustion system design, pollutant emission evaluations, combustion control, gas, oil, and coal burning, solid waste and wood burning, incineration of wastes, sewage sludge incineration, waste gas flares, hazardous waste combustion, NOx control, and improved combustion systems. Note: There is also an Instructor's Guide to be used in conducting the training course - (EPA-450/2-80-065) and a Student Workbook to be used for homework and in-class problem solving - (EPA-450/2-80-64).

Beard, J.T.; Iachetta, F.A.; Lilleleht, L.U.

1980-02-01

85

Thermal and emission characteristics of high temperature air combustion: A technical review  

Microsoft Academic Search

High temperature air combustion (HiTAC) is proved to be a promising combustion technology for industrial applications. HiTAC is more advantageous than conventional combustion technologies for several reasons: decreased energy consumption, enhanced heat transfer, the uniformity of temperature distribution, decreased CO2 emission, low NOX and CO emissions. This article provides a comprehensive picture of the recent research and developments in HiTAC.

Zhenjun Cao; Jin Chaohua

2010-01-01

86

Sooting and disruption in spherically symmetrical combustion of decane droplets in air  

NASA Technical Reports Server (NTRS)

The paper presents the results of experiments on the burning of individual 1-2 mm decane droplets in air at room temperature and atmospheric pressure. The NASA Lewis 2.2 s drop tower was used as well as a newly designed droplet-combustion apparatus that promotes nearly spherically symmetrical combustion. Unanticipated disruptions related to sooting behavior were encountered.

Dryer, F. L.; Williams, F. A.; Haggard, J. B., Jr.; Shaw, B. D.

1987-01-01

87

THE INFLUENCE OF AIR DISTRIBUTION RATE ON PARTICLE EMISSIONS IN FIXED BED COMBUSTION OF BIOMASS  

Microsoft Academic Search

Combustion of biomass under fixed-bed conditions will generate both coarse and fine particles that have a negative effect on technical performance or pose health hazards. It is therefore important to reduce the emissions of these particles that are already in the combustion process. The aim of this study was to experimentally investigate how different air supply strategies affect the particle

HENRIK WIINIKKA; RIKARD GEBART

2005-01-01

88

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)

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.

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

1989-01-01

89

Investigation into Oxygen-Enriched Bottom-Blown Stibnite and Direct Reduction  

NASA Astrophysics Data System (ADS)

The direct oxidation of stibnite (Sb2S3) using a gas mixture of nitrogen-oxygen was investigated in a pilot plant. Steady-state pilot operation of 5 and 10 t/d was normally observed during the pilot test of 100 days, and a cleaning experiment of high-antimony molten slag from oxygen-enriched bottom-blown was tested by direct reduction in a laboratory-scale electric furnace. Autogenous smelting was achieved without adding any other fuel, which guaranteed the feasibility and advantage of oxygen-enriched bottom-blown stibnite. Through analysis and calculation, the sulfur dioxide concentration in offgas was more than 8 pct, which meets the requirement for the preparation of sulfuric acid. In the reduction experiment, the effects of added CaO, the ratio of coal ( ? = actual weight of coal/theoretical weight of coal), and the slag type on the reduction procedure were considered. The residual slag obtained after reduction averaged less than 1 g/ton Au and less than 1 wt pct Sb. The metal phase contained iron less than 3 wt pct, and the recoveries of Au in the metal phase were more than 98 pct. This process shows significant environmental and economic benefits compared with previous processes.

Liu, Wei; Luo, Honglin; Qing, Wenqing; Zheng, Yongxing; Yang, Kang; Han, Junwei

2014-08-01

90

Suppression of premixed combustion dynamics utilizing microjet air injection  

E-print Network

The problem of thermoacoustic instability in continuous combustion systems is a major challenge in the field of propulsion and power generation. With the current environmental and political pressure that is being placed ...

Hudgins, Duane Edward

2008-01-01

91

Selling cold air DSM incentives lead to combustion turbine inlet air cooling opportunities for ESCOs  

SciTech Connect

Declining capacity margins and increasing competition among many electric utilities are putting new pressures on utility demand-side management (DSM) planners and the demand-side resource plans they develop. Most of this pressure has resulted from utilities` experiences with DSM programs that have not produced the impacts initially anticipated. Therefore, when responding to solicitations for demand-side resources, energy service companies (ESCOs) and other DSM contractors have been forced to focus increasingly on the measurability and reliability of the DSM packages they offer utilities. This paper proposes that combustion turbine (CT) inlet air cooling could be packaged as a demand-side resource to help utilities and ESCOs avoid the measurability and reliability problems of some other types of DSM programs. With CT inlet air cooling, in which ice is produced off-peak and stored for increasing CT capacity during summer peak periods by cooling the inlet air temperature, two utilities have obtained a reliable 67 MW (combined) resource for a total cost of about $15.4 million, or $230 per kW. Because this technology`s ability to meet peak demands is the result of predictable physical properties, the certainty of the impact of CT inlet air cooling is an attractive feature to electric utilities that are facing new competitive pressures to scrutinize the economics of all their DSM programs. This paper shows that minor modifications to existing DSM incentive mechanisms, such as PSE and G`s Standard Offer, could provide the necessary financing framework to lead to a boom in the CT inlet air cooling DSM market for ESCOs and other DSM contractors.

Sullivan, J.; Ebeling, J.A. [Burns and McDonnell Engineering Co., Kansas City, MO (United States)

1994-12-31

92

Combustion Velocity of Benzine-Benzol-Air Mixtures in High-Speed Internal-Combustion Engines  

NASA Technical Reports Server (NTRS)

The present paper describes a device whereby rapid flame movement within an internal-combustion engine cylinder may be recorded and determined. By the aid of a simple cylindrical contact and an oscillograph the rate of combustion within the cylinder of an airplane engine during its normal operation may be measured for gas intake velocities of from 30 to 35 m/s and for velocities within the cylinder of from 20 to 25 m/s. With it the influence of mixture ratios, of turbulence, of compression ratio and kind of fuel on combustion velocity may be determined. Besides the determination of the influence of the above factors on combustion velocity, the degree of turbulence may also be determined. As a unit of reference in estimating the degree of turbulence, the intake velocity of the charge is chosen.

Schnauffer, Kurt

1932-01-01

93

ANALYSIS OF A FUEL-AIR COMBUSTION MIXTURE BY INFRARED SPECTROSCOPY. Progress Report  

Microsoft Academic Search

A method of analysis is described for the products resulting from the ; incomplete combustion of a mixture of liquid hydrocarbon fuel and excess air. ; Gas sample generally is found to consist of air, unburned fuel, carbon dioxide, ; carbon monoxide, ethylene, and acetylene. These are first determined ; simultaneously by infrared absorptiometry. Then the sample is passed nitrogen

J. S. Whittick; R. F. Muraca

1959-01-01

94

Combustion of Gaseous Fuels with High Temperature Air in Normal- and Micro-gravity Conditions  

NASA Technical Reports Server (NTRS)

The objective of this study is determine the effect of air preheat temperature on flame characteristics in normal and microgravity conditions. We have obtained qualitative (global flame features) and some quantitative information on the features of flames using high temperature combustion air under normal gravity conditions with propane and methane as the fuels. This data will be compared with the data under microgravity conditions. The specific focus under normal gravity conditions has been on determining the global flame features as well as the spatial distribution of OH, CH, and C2 from flames using high temperature combustion air at different equivalence ratio.

Wang, Y.; Gupta, A. K.

2001-01-01

95

The adsorption of NO on YSZ(1 1 1) and oxygen-enriched YSZ(1 1 1) surfaces  

NASA Astrophysics Data System (ADS)

The reaction of NOx gases with yttria-stabilised zirconia (YSZ) surfaces, and in particular the oxygen enriched surfaces, is complex and of importance for gas sensing applications. In this letter the binding energy, vibrational frequencies, density of states, magnetic moments, electron localization, and charge transfer are presented for all stable configurations of NO on YSZ(1 1 1) and oxygen-enriched YSZ + O(1 1 1) surfaces, determined using density functional theory calculations. Complementary ab initio molecular dynamics simulations revealed the adsorption characteristics of NO at 298 and 773 K. Our findings can be used to assist in explaining the reactions of NOx gases that occur on electrochemical gas sensors.

Breedon, M.; Spencer, M. J. S.; Miura, N.

2014-02-01

96

Characteristics of Gaseous Diffusion Flames with High Temperature Combustion Air in Microgravity  

NASA Technical Reports Server (NTRS)

The characteristics of gaseous diffusion flames have been obtained using high temperature combustion air under microgravity conditions. The time resolved flame images under free fall microgravity conditions were obtained from the video images obtained. The tests results reported here were conducted using propane as the fuel and about 1000 C combustion air. The burner included a 0.686 mm diameter central fuel jet injected into the surrounding high temperature combustion air. The fuel jet exit Reynolds number was 63. Several measurements were taken at different air preheats and fuel jet exit Reynolds number. The resulting hybrid color flame was found to be blue at the base of the flame followed by a yellow color flame. The length and width of flame during the entire free fall conditions has been examined. Also the relative flame length and width for blue and yellow portion of the flame has been examined under microgravity conditions. The results show that the flame length decreases and width increases with high air preheats in microgravity condition. In microgravity conditions the flame length is larger with normal temperature combustion air than high temperature air.

Ghaderi, M.; Gupta, A. K.

2003-01-01

97

Swozzle based burner tube premixer including inlet air conditioner for low emissions combustion  

DOEpatents

A burner for use in a combustion system of a heavy-duty industrial gas turbine includes a fuel/air premixer having an air inlet, a fuel inlet, and an annular mixing passage. The fuel/air premixer mixes fuel and air into a uniform mixture for injection into a combustor reaction zone. The burner also includes an inlet flow conditioner disposed at the air inlet of the fuel/air premixer for controlling a radial and circumferential distribution of incoming air. The pattern of perforations in the inlet flow conditioner is designed such that a uniform air flow distribution is produced at the swirler inlet annulus in both the radial and circumference directions. The premixer includes a swozzle assembly having a series of preferably air foil shaped turning vanes that impart swirl to the airflow entering via the inlet flow conditioner. Each air foil contains internal fuel flow passages that introduce natural gas fuel into the air stream via fuel metering holes that pass through the walls of the air foil shaped turning vanes. By injecting fuel in this manner, an aerodynamically clean flow field is maintained throughout the premixer. By injecting fuel via two separate passages, the fuel/air mixture strength distribution can be controlled in the radial direction to obtain optimum radial concentration profiles for control of emissions, lean blow outs, and combustion driven dynamic pressure activity as machine and combustor load are varied.

Tuthill, Richard Sterling (Bolton, CT); Bechtel, II, William Theodore (Scotia, NY); Benoit, Jeffrey Arthur (Scotia, NY); Black, Stephen Hugh (Duanesburg, NY); Bland, Robert James (Clifton Park, NY); DeLeonardo, Guy Wayne (Scotia, NY); Meyer, Stefan Martin (Troy, NY); Taura, Joseph Charles (Clifton Park, NY); Battaglioli, John Luigi (Glenville, NY)

2002-01-01

98

Stable products and some kinetic features of dichlorosilane-air combustion  

Microsoft Academic Search

The ignition and combustion of silanes is important in the manufacturing of solid products used in the microelectronics industry. In this study, the amounts of Hâ, HCl, and HâO in the reaction products of the combustion of dichlorosilane-air mixtures containing from 1 to 100% of dichlorosilane were determined. The explosion concentration limits (2.4 and 94%) were estimated under standard conditions

R. G. Aivazyan; V. V. Azatyan; V. I. Kalachev; T. A. Sinelnikova

1995-01-01

99

The Effect of Air\\/Fuel Ratio on Properties and Reactivity of Combustion Soots  

Microsoft Academic Search

The dependence of specific properties of black carbon (BC) soots on fuel type and combustion conditions has been studied, and the effects of these properties on soot particle hydration and reaction with ozone determined. Series of soots were prepared from n-hexane, diesel and JP8 aircraft fuels, utilizing a flow combustion system designed for accurate control of the air\\/fuel ratio in

A. R. Chughtai; J. M. Kim; D. M. Smith

2002-01-01

100

Retene-a molecular marker of wood combustion in ambient air  

NASA Astrophysics Data System (ADS)

The use of wood as a fuel has increased since the oil embargo in 1973. Several studies have shown that wood combustion may make a significant contribution to air pollution. Using 14C as a tracer for contemporary carbonaceous materials, 30-70% of the atmospheric carbon has been shown to originate from wood combustion in areas affected by this source1-3. Other studies have shown that emissions from wood combustion contain large amounts of particles4-6 and organic compounds, one class being poly cyclic aromatic hydrocarbons (PAH)7-11. However, these compounds are also formed by combustion of other carbonaceous materials. In our studies on PAH in wood combustion emissions and in ambient air in wood-heated residential areas, we have identified several PAH compounds which may be related to combustion of coniferous wood. These are alkylated phenanthrene compounds with the main compound 1-methyl-7-isopropylphenanthrene (trivial name retene) formed by thermal degradation of resin compounds in the wood.

Ramdahl, Thomas

1983-12-01

101

Recombination of Hydrogen-Air Combustion Products in an Exhaust Nozzle  

NASA Technical Reports Server (NTRS)

Thrust losses due to the inability of dissociated combustion gases to recombine in exhaust nozzles are of primary interest for evaluating the performance of hypersonic ramjets. Some results for the expansion of hydrogen-air combustion products are described. Combustion air was preheated up to 33000 R to simulate high-Mach-number flight conditions. Static-temperature measurements using the line reversal method and wall static pressures were used to indicate the state of the gas during expansion. Results indicated substantial departure from the shifting equilibrium curve beginning slightly downstream of the nozzle throat at stagnation pressures of 1.7 and 3.6 atmospheres. The results are compared with an approximate method for determining a freezing point using an overall rate equation for the oxidation of hydrogen.

Lezberg, Erwin A.; Lancashire, Richard B.

1961-01-01

102

Air and oxy-fuel combustion characteristics of biomass\\/lignite blends in TGA-FTIR  

Microsoft Academic Search

Pyrolysis and combustion behavior of indigenous lignite, olive residue and their 50\\/50wt.% blend in air and oxy-fuel conditions were investigated by using thermogravimetric analyser (TGA) combined with Fourier-transform infrared (FTIR) spectrometer. Pyrolysis tests were carried out in nitrogen and carbon dioxide environments which are the main diluting gasses of air and oxy-fuel environment, respectively. Pyrolysis results of the parent fuels

Nur Sena Yuzbasi; Nevin Selçuk

2011-01-01

103

Experimental investigation of fuel combustion in counterflowing high-temperature air flow  

Microsoft Academic Search

The possibility of using high-energy synthetic hydrocarbon fuels, borane fuels, as well as borohydrocarbon fuels are currently being studied for use by various kinds of aircraft with jet engines. The problem addressed in this work included experimental determination of the geometric characteristics of the vaporization and combustion zones of borohydrocarbon fuel sprayed in a counterflowing air flow and comparing them

Y. M. Annushkin; A. N. Knyazev; N. S. Loshenkova

1983-01-01

104

BATTERY POWERED PM-10 INDOOR AIR SAMPLERS APPLIED TO UNVENTED THIRD WORLD RESIDENTIAL COMBUSTION SOURCES  

EPA Science Inventory

The paper discusses a battery-powered PM-10 indoor air sampler applied to unvented Third World residential combustion sources. (NOTE: Specialized PM-10 sampling systems have been developed and used in support of a joint U.S. EPA/People's Republic of China Institute of Environment...

105

HAZARDOUS AIR POLLUTANTS FROM THE COMBUSTION OF AN EMULSIFIED HEAVY FUEL OIL IN A FIRETUBE BOILER  

EPA Science Inventory

The report gives results of measuring emissions of hazardous air pollutants (HAPs) from the combustion flue gases of a No. 6 fuel oil, both with and without an emulsifying agent, in a 2.5 million Btu/hr (732 kW) firetube boiler with the purpose of determining the impacts of the e...

106

Control of air toxin particulate and vapor emissions after coal combustion utilizing calcium magnesium acetate  

Microsoft Academic Search

Major environmental issues are now coming to the forefront in all parts of the globe with increased public awareness of the human health effects and the possible effects on our global environment. Modern control technologies, when implemented, have significantly reduced air pollution emissions that are a result of coal combustion during this century. However, the emissions have not been completely

Judith Irene Shuckerow; Judith Anne Steciak; Donald L. Wise; Yiannis A. Levendis; Girard A. Simons; Joseph D. Gresser; Edgar B. Gutoff; C. David Livengood

1996-01-01

107

Method and apparatus for regulating the fuel-air ratio in internal combustion engines  

Microsoft Academic Search

A method and an apparatus for regulating the fuel-air ratio of the operational mixture of an internal combustion engine and for monitoring the operational readiness of a lambda sensor controlling the regulating apparatus and functioning according to the principle of ionic conduction in fixed electrolytes. A constant reference voltage which approximately corresponds to the average sensor output voltage is connected

U. Drews; W. Mohrle; P. Werner

1982-01-01

108

Device for regulating the fuel-air ratio in internal combustion engines  

Microsoft Academic Search

A device is proposed for regulating the fuel-air ratio in the operating mixture of an internal combustion engine and for monitoring the operational readiness of a lambda sensor controlling the regulating device and functioning by the principle of ion conduction in solid electrolytes. The lambda sensor has an adjustable, constant reference voltage switched opposite to it. The reference voltage approximately

U. Drews; W. Mohrle; P. Werner

1983-01-01

109

Air pollution from aircraft. [jet exhaust - aircraft fuels/combustion efficiency  

NASA Technical Reports Server (NTRS)

A model which predicts nitric oxide and carbon monoxide emissions from a swirl can modular combustor is discussed. A detailed analysis of the turbulent fuel-air mixing process in the swirl can module wake region is reviewed. Hot wire anemometry was employed, and gas sampling analysis of fuel combustion emissions were performed.

Heywood, J. B.; Chigier, N. A.

1975-01-01

110

PIC (PRODUCTS OF INCOMPLETE COMBUSTION) FORMATION UNDER PYROLYTIC AND STARVED AIR CONDITIONS  

EPA Science Inventory

A comprehensive program of laboratory studies based on the non-flame mode of thermal decomposition produced much data on PIC (Products of Incomplete Combustion) formation, primarily under pyrolytic and starved air conditions. Most significantly, laboratory results from non-flame ...

111

Experimental investigation of wood combustion in a fixed bed with hot air.  

PubMed

Waste combustion on a grate with energy recovery is an important pillar of municipal solid waste (MSW) management in the Netherlands. In MSW incinerators fresh waste stacked on a grate enters the combustion chamber, heats up by radiation from the flame above the layer and ignition occurs. Typically, the reaction zone starts at the top of the waste layer and propagates downwards, producing heat for drying and devolatilization of the fresh waste below it until the ignition front reaches the grate. The control of this process is mainly based on empiricism. MSW is a highly inhomogeneous fuel with continuous fluctuating moisture content, heating value and chemical composition. The resulting process fluctuations may cause process control difficulties, fouling and corrosion issues, extra maintenance, and unplanned stops. In the new concept the fuel layer is ignited by means of preheated air (T>220 °C) from below without any external ignition source. As a result a combustion front will be formed close to the grate and will propagate upwards. That is why this approach is denoted by upward combustion. Experimental research has been carried out in a batch reactor with height of 4.55 m, an inner diameter of 200 mm and a fuel layer height up to 1m. Due to a high quality two-layer insulation adiabatic conditions can be assumed. The primary air can be preheated up to 350 °C, and the secondary air is distributed via nozzles above the waste layer. During the experiments, temperatures along the height of the reactor, gas composition and total weight decrease are continuously monitored. The influence of the primary air speed, fuel moisture and inert content on the combustion characteristics (ignition rate, combustion rate, ignition front speed and temperature of the reaction zone) is evaluated. The upward combustion concept decouples the drying, devolatilization and burnout phase. In this way the moisture and inert content of the waste have almost no influence on the combustion process. In this paper an experimental comparison between conventional and reversed combustion is presented. PMID:24125795

Markovic, Miladin; Bramer, Eddy A; Brem, Gerrit

2014-01-01

112

Copper contamination effects on hydrogen-air combustion under SCRAMJET (supersonic combustion ramjet) testing conditions  

SciTech Connect

Two forms of copper catalytic reactions (homogeneous and heterogeneous) in hydrogen flames were found in a literature survey. Hydrogen atoms in flames recombine into hydrogen molecules through catalytic reactions, and these reactions which affect the timing of the combustion process. Simulations of hydrogen flames with copper contamination were conducted by using a modified general chemical kinetics program (GCKP). Results show that reaction times of hydrogen flames are shortened by copper catalytic reactions, but ignition times are relatively insensitive to the reactions. The reduction of reaction time depends on the copper concentration, copper phase, particle size (if copper is in the condensed phase), and initial temperature and pressure. The higher the copper concentration of the smaller the particle, the larger the reduction in reaction time. For a supersonic hydrogen flame (Mach number = 4.4) contaminated with 200 ppm of gaseous copper species, the calculated reaction times are reduced by about 9%. Similar reductions in reaction time are also computed for heterogeneous copper contamination. Under scramjet testing conditions, the change of combustion timing appears to be tolerable (less than 5%) if the Mach number is lower than 3 or the copper contamination is less than 100 ppm. The higher rate the Mach number, the longer the reaction time and the larger the copper catalytic effects. 7 tabs., 8 figs., 34 refs.

Chang, S.L.; Lottes, S.A.; Berry, G.F.

1990-01-01

113

Numerical Study of Contaminant Effects on Combustion of Hydrogen, Ethane, and Methane in Air  

NASA Technical Reports Server (NTRS)

A numerical study was performed to assess the effects of vitiated air on the chemical kinetics of hydrogen, ethane, and methane combustion with air. A series of calculations in static reacting systems was performed, where the initial temperature was specified and reactions occurred at constant pressure. Three different types of test flow contaminants were considered: NP, H2O, and a combustion of H2O and CO2. These contaminants are present in the test flows of facilities used for hypersonic propulsion testing. The results were computed using a detailed reaction mechanism and are presented in terms of ignition and reaction times. Calculations were made for a wide range of contaminant concentrations, temperatures and pressures. The results indicate a pronounced kinetic effect over a range of temperatures, especially with NO contamination and, to a lesser degree, with H2O contamination. In all cases studied, CO2 remained kinetically inert, but had a thermodynamic effect on results by acting as a third body. The largest effect is observed with combustion using hydrogen fuel, less effect is seen with combustion of ethane, and little effect of contaminants is shown with methane combustion.

Lai, H. T.; Thomas, S. R.

1995-01-01

114

Chaotic dynamics in premixed hydrogen\\/air channel flow combustion  

Microsoft Academic Search

The complex oscillatory behaviour observed in fuel-lean premixed hydrogen\\/air atmospheric pressure flames in an open planar channel with prescribed wall temperature is investigated by means of direct numerical simulations, employing detailed chemistry descriptions and species transport, and nonlinear dynamics analysis. As the inflow velocity is varied, the sequence of transitions includes harmonic single frequency oscillations, intermittency, mixed mode oscillations, and

Gianmarco Pizza; Christos E. Frouzakis; John Mantzaras

2011-01-01

115

Chaotic dynamics in premixed hydrogen\\/air channel flow combustion  

Microsoft Academic Search

The complex oscillatory behaviour observed in fuel-lean premixed hydrogen\\/air atmospheric pressure flames in an open planar channel with prescribed wall temperature is investigated by means of direct numerical simulations, employing detailed chemistry descriptions and species transport, and nonlinear dynamics analysis. As the inflow velocity is varied, the sequence of transitions includes harmonic single frequency oscillations, intermittency, mixed mode oscillations, and

Gianmarco Pizza; Christos E. Frouzakis; John Mantzaras

2012-01-01

116

GASEOUS EMISSIONS FROM EXCESS AIR COMBUSTION OF EXPLOSIVES AND PROPELLANTS  

EPA Science Inventory

The purpose of this short-term project was to determine the levels of nitric oxide (NO), nitrogen dioxide (NO2), and carbon monoxide (CO) in the off-gases from the open burning of explosives in excess air. The ultimate goal is to reduce the level of NO(x), CO, and particulates em...

117

Combustion characteristics of pulverized coal and air/gas premixed flame in a double swirl combustor  

SciTech Connect

An experimental work was performed to investigate the co-firing of pulverized coal and premixed gas/air streams in a double swirl combustor. The results showed that the NOx emissions are affected by the relative rates of thermal NOx formation and destruction via the pyrolysis of the fuel-N species in high temperature fuel-rich zones. Various burner designs were tested in order to vary the temperature history and the residence time across both coal and gas flames inside the furnace. It was found that by injecting the coal with a gas/air mixture as a combined central jet surrounded by a swirled air stream, a double flame envelope develops with high temperature fuel-rich conditions in between the two reaction zones such that the pyrolysis reactions to N{sub 2} are accelerated. A further reduction in the minimum NOx emissions, as well as in the minimum CO concentrations, was reported for the case where the coal particles are fed with the gas/air mixture in the region between the two swirled air streams. On the other hand, allocating the gas/air mixture around the swirled air-coal combustion zone provides an earlier contact with air and retards the NOx reduction mechanism in such a way that the elevated temperatures around the coal particles allow higher overall NOx emissions. The downstream impingement of opposing air jets was found more efficient than the impinging of particle non-laden premixed flames for effective NOx reduction. In both cases, there is an upstream flow from the stagnation region to the coal primary combustion region, but with the case of air impingement, the hot fuel-rich zone develops earlier. The optimum configuration was found by impinging all jets of air and coal-gas/air mixtures that pronounced minimum NOx and CO concentrations of 310 and 480ppm, respectively.

Kamal, M.M. [Ain Shams University, Cairo (Egypt). Faculty of Education

2009-07-01

118

Air toxic emissions from the combustion of coal: Identifying and quantifying hazardous air pollutants from US coals  

SciTech Connect

This report addresses the key air toxic emissions likely to emanate from continued and expanded use of domestic coal. It identifies and quantifies those trace elements specified in the US 1990 Clean Air Act Amendments, by tabulating selected characterization data on various source coals by region, state, and rank. On the basis of measurements by various researchers, this report also identifies those organic compounds likely to be derived from the coal combustion process (although their formation is highly dependent on specific boiler configurations and operating conditions).

Szpunar, C.B.

1992-09-01

119

Catalytic Combustion of Propane\\/Air Mixtures on Platinum  

Microsoft Academic Search

A honeycomb catalyst of platinum (4.2 kg\\/m loading) over cordierite, with y-alumina washcoat, 2.4 × 2.4 cm in crosssection, 7·6 cm long and with characteristic channel diameter of 1·4 mm was used in a steady flow reactor. Measurements were made with CaHs\\/air mixtures at 650 to 800 K inlet temperatures, 110 KPa pressure, 10 to 40 m\\/s inlet velocity, 0·19 to 0·32 equivalence ratios,

C. BRUNO; P. M. Walsh; D. A. SANTAVICCA; N. SINHA; Y. YAW; F. V. BRACCO

1983-01-01

120

Utilization of ventilation air methane as a supplementary fuel at a circulating fluidized bed combustion boiler  

SciTech Connect

Ventilation air methane (VAM) accounts for 60-80% of the total emissions from underground coal mining activities in China, which is of serious greenhouse gas concerns as well as a waste of valuable fuel sources. This contribution evaluates the use of the VAM utilization methods as a supplementary fuel at a circulating fluidized bed combustion boiler. The paper describes the system design and discusses some potential technical challenges such as methane oxidation rate, corrosion, and efficiency. Laboratory experimentation has shown that the VAM can be burnt completely in circulated fluidized bed furnaces, and the VAM oxidation does not obviously affect the boiler operation when the methane concentration is less than 0.6%. The VAM decreased the incomplete combustion loss for the circulating fluidized bed combustion furnace. The economic benefit from the coal saving insures that the proposed system is more economically feasible. 17 refs., 3 figs., 1 tab.

Changfu You; Xuchang Xu [Tsinghua University, Beijing (China). Key Laboratory for Thermal Science and Power Engineering of Ministry of Education

2008-04-01

121

Multipathway human health risk assessment concerning air emissions from combustion of Orimulsion fuel  

SciTech Connect

A multipathway human health risk assessment was conducted concerning air emissions from the combustion of Orimulsion. Exposure was considered for nearby residents who might be exposed by oral, dermal or inhalation pathways, including ingestion of analytes that may be present in meat and agricultural products from nearby areas. Occupational exposure were evaluated via the same intake pathways, except for potential ingestion of food products. Pathways included airborne exposures, deposition on crops, exposures to soils, and uptake by livestock and plants. Livestock intake included ingestion of analytes retained by plants and inhalation of soil-bound particulates. Analytes of potential concern included compounds identified as combustion products of the orimulsion fuel. Air concentrations of analytes, and the areal distribution of these concentrations resulting from stack emissions, were predicted using transport and deposition models. A worst cast scenario for air and cumulative soil concentrations was considered to represent the entire facility project lifetime (20 years) for dry deposition as well as predicted air concentrations occurring at continuous 100% facility operating capacity. Potential exposures to sulfuric acid mist and lead were shown to be much less than levels protective of human populations. Based upon the airborne emissions estimates and the deposition estimates for other constituents of interest, as well as the strongly conservative estimates of the potential for human intake, local health risks contributed from the combustion of Orimulsion fuel at the facility were judged to be negligible.

Teaf, C.M.; Coleman, R.M.; Manning, M.J.; Covert, D.J.; Phelps, J.L.

1995-12-31

122

Premixed CH4/O2-enriched air combustion: Identification of thermal, chemical and aerodynamic effects  

NASA Astrophysics Data System (ADS)

This work contributes to the evaluation of a new innovative process focused on the reduction of the cost of a post-combustion capture of CO2 in a Carbon Capture and Storage system (CCS). The process based on the separation of dried fumes composed mainly by CO2 and N2 by using membranes, which should lead to a lower energetic separation cost than amines. But the membranes become efficient if the upstream CO2 concentration is higher than 30% at their entrance that requires enriching the oxidizer flow by O2. To maintain the exhaust temperature compatible with materials thermal resistance, the reactants are diluted by a recirculation of a part of the flue gases (like N2/O2/CO2). But, the chemical kinetic, the energetic efficiencies, the radiation transfer, the transport and thermal properties of the flow can be affected by CO2. The objective of this work will be to identify the behaviour of the combustion of premixed CH4/O2-enriched air, both diluted in N2 and CO2 and to determine the combustion parameters. This allows to recover the CH4/air conditions in terms of CO2 concentration in reactants, O2 excess, dilution rate, temperature of the reactants, etc. Experiments are performed on the laminar premixed flame using counterflow burner. To characterize the combustion behaviour, the flammability limits are determined and flame thickness and position are measured from PLIF-OH diagnostic. Further, CHEMKIN simulations are performed to check the validity of the GRI3.0 chemical kinetic mechanism for premixed CH4/air synthetic combustion and identify the leading phenomena.

Most, J.-M.; Dahikar, S.; Pal, S.; Claverie, A.; Denis, D.; Pillier, L.; de Persis, S.

2012-11-01

123

Numerical study of contaminant effects on combustion of hydrogen, ethane, and methane in air  

NASA Technical Reports Server (NTRS)

A numerical study was performed to assess the effects of vitiated air on the chemical kinetics of hydrogen, ethane, and methane combustion with air. A series of calculations in static reacting systems was performed, where the initial temperature was specified and reactions occurred at constant pressure. Three different types of test flow contaminants were considered: NO, H2O, and a combination of H2O and CO2. These contaminants are present in the test flows of facilities used for hypersonic propulsion testing. The results were computed using a detailed reaction mechanism and are presented in terms of ignition and reaction times. Calculations were made for a wide range of contaminant concentrations, temperatures and pressures. The results indicate a pronounced kinetic effect over a range of temperatures, especially with NO contamination and, to a lesser degree, with H2O contamination. In all cases studied, CO2 remained kinetically inert, but had a thermodynamically effect on results by acting as a third body. The largest effect is observed with combustion using hydrogen fuel, less effect is seen with combustion of ethane, and little effect of contaminants is shown with methane combustion.

Lai, H. T.; Thomas, S. R.

1995-01-01

124

Investigation on combustion characteristics and NO formation of methane with swirling and non-swirling high temperature air  

NASA Astrophysics Data System (ADS)

Combustion characteristics of methane jet flames in an industrial burner working in high temperature combustion regime were investigated experimentally and numerically to clarify the effects of swirling high temperature air on combustion. Speziale-Sarkar-Gatski (SSG) Reynolds stress model, Eddy-Dissipation Model (EDM), Discrete Ordinates Method (DTM) combined with Weighted-Sum-of-Grey Gases Model (WSGG) were employed for the numerical simulation. Both Thermal-NO and Prompt-NO mechanism were considered to evaluate the NO formation. Temperature distribution, NO emissions by experiment and computation in swirling and non-swirling patterns show combustion characteristics of methane jet flames are totally different. Non-swirling high temperature air made high NO formation while significant NO prohibition were achieved by swirling high temperature air. Furthermore, velocity fields, dimensionless major species mole fraction distributions and Thermal-NO molar reaction rate profiles by computation interpret an inner exhaust gas recirculation formed in the combustion zone in swirling case.

Li, Xing; Jia, Li

2014-10-01

125

Hazardous air pollutant emissions from gas-fired combustion sources: emissions and the effects of design and fuel type  

Microsoft Academic Search

Air emissions from gas-fired combustion devices such as boilers, process heaters, gas turbines and stationary reciprocating engines contain hazardous air pollutants (HAPs) subjected to consideration under the federal clean air act (CAA). This work presents a recently completed major research project to develop an understanding of HAP emissions from gas-fired boilers and process heaters and new HAP emission factors based

Glenn C England; Thomas P McGrath; Lee Gilmer; James G Seebold; Miriam Lev-On; Timothy Hunt

2001-01-01

126

Unique, clean-air, continuous-flow, high-stagnation-temperature facility for supersonic combustion research  

NASA Technical Reports Server (NTRS)

Accurate, spatially-resolved measurements can be conducted of a model supersonic combustor in a clean air/continuous flow supersonic combustion facility whose long run times will allow not only the point-by-point mapping of flow field variables with laser diagnostics but facilitate the simulation of steady-state combustor conditions. The facility will provide a Mach 2 freestream with static pressures in the 1 to 1/6 atm range, and stagnation temperatures of up to 2000 K.

Krauss, R. H.; Mcdaniel, J. C., Jr.; Scott, J. E., Jr.; Whitehurst, R. B., III; Segal, C.

1988-01-01

127

Catalytic Combustion of Propane/Air Mixtures on Platinum  

NASA Technical Reports Server (NTRS)

A honeycomb catalyst of platinum (4.2 kg/cu m loading) over cordierite, with gamma-alumina washcoat, a cross section of 2.4 x 2.4 sq cm, a length of 7.6 cm, and a characteristic channel diameter of 1.4 mm is used as a steady flow reactor. Measurements are made with C3H8/air mixtures at 650 to 800 K inlet temperatures, 110 KPa pressure, 10 to 40 m/s inlet velocity, 0.19 to 0.32 equivalence ratios, and approximately 1.5 mole percent water content. The measured quantities are the substrate tempeature at ten axial locations, the exhaust gas temperature, the exhaust concentrations of CO, CO2, O2, and total hydrocarbons, and the pressure drop across the monolith. The measured quantities are compared with those computed with a two-dimensional steady-state model for axial and radial convection and diffusion of mass, momentum, energy and homogeneous (three overall reactions) and heterogeneous (infinitely fast) reactions. It is found that, under the tested conditions, most of the fuel is converted to CO2 and H2O at the surface. Gas-phase reactions tend rapidly to become more important as the temperature and equivalence ratio are increased and the flow velocity is decreased. Surface fuel conversion is much more rapid than fuel diffusion, resulting in diffusion-controlled oxidation.

Bruno, C.; Walsh, P. M.; Santavicca, D. A.; Sinha, N.; Bracco, F. V.; Yaw, Y.

1983-01-01

128

Analytical evaluation of effect of equivalence ratio inlet-air temperature and combustion pressure on performance of several possible ram-jet fuels  

NASA Technical Reports Server (NTRS)

The results of an analytical investigation of the theoretical air specific impulse performance and adiabatic combustion temperatures of several possible ram-jet fuels over a range of equivalence ratios, inlet-air temperatures, and combustion pressures, is presented herein. The fuels include octane-1, 50-percent-magnesium slurry, boron, pentaborane, diborane, hydrogen, carbon, and aluminum. Thermal effects from high combustion temperatures were found to effect considerably the combustion performance of all the fuels. An increase in combustion pressure was beneficial to air specific impulse at high combustion temperatures. The use of these theoretical data in engine operation and in the evaluation of experimental data is described.

Tower, Leonard K; Gammon, Benson E

1953-01-01

129

Flatness-based embedded control of air-fuel ratio in combustion engines  

NASA Astrophysics Data System (ADS)

A nonlinear controller is designed for air-fuel ratio control in combustion engines, making use of differential flatness theory and of the Derivative-free nonlinear Kalman Filter. It is proven that the air-fuel ratio system is a differentially flat one and admits dynamic feedback linearization. Using a change of variables that is based on differential flatness theory it is shown that the air-fuel ratio system can be transformed to the linear canonical form, for which the design of a state feedback controller is easier. Moreover, to compensate for modeling uncertainties and external disturbances the Derivative-free nonlinear Kalman Filter is designed as a disturbance observer. The estimation of the perturbations that effect the air-fuel systems enables their compensation through the inclusion of an additional term in the feedback control law. The efficiency of the proposed nonlinear feedback control scheme is tested through simulation experiments.

Rigatos, Gerasimos; Siano, Pierluigi; Arsie, Ivan

2014-10-01

130

Combustion  

NASA Technical Reports Server (NTRS)

An overview of the emissions related research being conducted as part of the Fundamental Aeronautics Subsonics Fixed Wing Project is presented. The overview includes project metrics, milestones, and descriptions of major research areas. The overview also includes information on some of the emissions research being conducted under NASA Research Announcements. Objective: Development of comprehensive detailed and reduced kinetic mechanisms of jet fuels for chemically-reacting flow modeling. Scientific Challenges: 1) Developing experimental facilities capable of handling higher hydrocarbons and providing benchmark combustion data. 2) Determining and understanding ignition and combustion characteristics, such as laminar flame speeds, extinction stretch rates, and autoignition delays, of jet fuels and hydrocarbons relevant to jet surrogates. 3) Developing comprehensive kinetic models for jet fuels.

Bulzan, Dan

2007-01-01

131

Combustion  

NSDL National Science Digital Library

In this chemistry activity, learners discover that the weight of the product of combustion is greater than that of the starting material. Learners will compare the weight of steel wool before and after it is heated. Learners are asked to consider why the steel wool weighs more (oxidation) as well as write the balanced chemical equation for the burning of steel. This activity uses an open flame; adult supervision is recommended. The resource includes notes for educators and extension ideas.

House, The S.

2014-01-28

132

Experimental plan for the assessment of air toxic emissions from a pilot-scale combustion unit  

SciTech Connect

The operation of a 500-pound-per-hour pilot-scale combustion unit will be characterized in terms of the formation, distribution, and fate of toxic substances. The coal fired during the air toxics testing will be the same coal batch that had been fired in a full-scale utility boiler during a recent assessment of air toxic emissions. A description of the pilot unit and expected operating conditions during the air toxics testing is provided, along with a summary of the test plan. This test plan is designed to obtain the necessary data on the concentration of trace elements associated with the vapor phase, particulate phase, and particulate size fraction enabling a comparison of these results form the pilot unit and the full-scale utility. Calculation of material balances around the pilot combustion unit, the baghouse, and the overall system as well as baghouse removal efficiencies will be performed. Based on the results of this air toxics characterization effort, an assessment will be made of the value of the pilot unit as a facility for the evaluation of sampling and analytical improvements, development of continuous emissions monitors, and future control systems evaluations.

Hargis, R.A.; Pennline, H.W. [Dept. of Energy, Pittsburgh, PA (United States). Pittsburgh Energy Technology Center

1995-12-31

133

Initiation of diffusion combustion in a supersonic flow of H2 air mixture by electrical-discharge-excited oxygen molecules  

NASA Astrophysics Data System (ADS)

The methodology of arranging a stable combustion in a diffusion mode in a supersonic non-premixed H2-air flow at a short distance and at a low air temperature due to excitation of O2 molecules to the a 1?g and b\\,^{1}\\!\\Sigma _g^+ states in the electrical discharge is considered. It is shown that for initiation of combustion in this case, it is sufficient to subject the oxygen molecules to an electrical discharge in a thin (with a thickness of 0.5-1 cm) layer located between hydrogen and air streams. It is shown that the mechanism of combustion enhancement is caused by accelerating the chain reactions due to the abundance of excited oxygen molecules in a shear layer and has a non-thermal character. This paper was presented at the Third International Symposium on Nonequilibrium Processes, Combustion, and Atmospheric Phenomena (Dagomys, Sochi, Russia, 25-29 June 2007).

Starik, A. M.; Titova, N. S.; Bezgin, L. V.; Kopchenov, V. I.

2008-06-01

134

Numerical modelling of air supply and air flow pattern of a room that contains a gas appliance with open combustion chamber  

Microsoft Academic Search

SUMMARY In the last decade, quite a few carbon-monoxide intoxications occurred in Hungary due to the inadequate operation of gas appliances with open combustion chamber, connected to chimneys. These cases emphasized the importance of faultless air supply of the appliances and the safe removal of the incipient flue gases. This problem gave reason for the modelling of air supply, temperature

Lajos Barn; Róbert God

135

Study of effects of injector geometry on fuel-air mixing and combustion  

NASA Technical Reports Server (NTRS)

An implicit finite-difference method has been developed for computing the flow in the near field of a fuel injector as part of a broader study of the effects of fuel injector geometry on fuel-air mixing and combustion. Detailed numerical results have been obtained for cases of laminar and turbulent flow without base injection, corresponding to the supersonic base flow problem. These numerical results indicated that the method is stable and convergent, and that significant savings in computer time can be achieved, compared with explicit methods.

Bangert, L. H.; Roach, R. L.

1977-01-01

136

Interaction of the burning spherical droplets in oxygen-enriched turbulent environment  

SciTech Connect

Three-dimensional numerical studies on the interaction of vaporizing and burning droplets were conducted to understand the burning characteristics of multiple droplets in a turbulent environment. The burning droplets characteristics, such as lifetime, surface temperature, vaporization, reaction, and burning rate were examined for various oxygen mole-fractions and geometrical arrangements of droplets. Results from a single droplet combustion test were first verified and validated against existing experimental data. Results indicate that turbulent intensity has a moderate effect on droplet burning rate, but not as prominent an effect as the oxygen mole-fraction. At high oxygen mole-fractions, droplet lifetime was short due to enhanced burning. It is shown that evaporation processes of multiple droplets are notably affected by the inter-space distance between droplets both in streamwise and spanwise directions. The burning rate as a function of oxygen mole-fraction and inter-space distance is determined and can be used as a guideline for future studies on spray combustion. (author)

Cho, Chong Pyo [Automobile Energy and Environment Research Center, Korea Institute of Energy Research, 71-2 Jangdong, Yuseonggu, Daejeon, 305-343 (Korea); Kim, Ho Young; Yoon, Sam S. [Department of Mechanical Engineering, Korea University, Anamdong, 5-Ga, Sungbukgu, Seoul, 136-701 (Korea)

2009-01-15

137

Promoted Combustion Test Data Re-Examined  

NASA Technical Reports Server (NTRS)

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.

Lewis, Michelle; Jeffers, Nathan; Stoltzfus, Joel

2010-01-01

138

Fuel-air mixing and combustion in a two-dimensional Wankel engine  

NASA Technical Reports Server (NTRS)

A two-equation turbulence model, an algebraic grid generalization method, and an approximate factorization time-linearized numerical technique are used to study the effects of mixture stratification at the intake port and gaseous fuel injection on the flow field and fuel-air mixing in a two-dimensional rotary engine model. The fuel distribution in the combustion chamber is found to be a function of the air-fuel mixture fluctuations at the intake port. It is shown that the fuel is advected by the flow field induced by the rotor and is concentrated near the leading apex during the intake stroke, while during compression, the fuel concentration is highest near the trailing apex and is lowest near the rotor. It is also found that the fuel concentration near the trailing apex and rotor is small except at high injection velocities.

Shih, T. I.-P.; Schock, H. J.; Ramos, J. I.

1987-01-01

139

Megacity and country emissions from combustion sources-Buenos Aires-Argentina  

NASA Astrophysics Data System (ADS)

Historic time series (1970-2006) emissions of greenhouse gases and air pollutants arising from stationary and mobile combustion sources were estimated at national level for Argentina and at regional level for the metropolitan area of Buenos Aires (MABA). All emissions were estimated using a bottom-up approach following the IPCC good practice guidance. For mobile sources, national emissions include all transport categories. Regional emissions account thus far only for on-road. For national emissions, methodologies and guidance by the IPCC were employed, applying the highest possible tier and using: i)country-specific emission factors for carbon and sulphur and technology-based information for other species, ii)activity data from energy balance series (1970-2007), and iii)complementary information concerning the non-energy use of fuels. Regional emissions in 2006 were estimated in-depth using a technology-based approach for the city of Buenos Aires (CBA) and the 24 neighboring districts composing the MABA. A regional emissions factors database was developed to better characterize Latin American fleets and driving conditions employing COPERT III-IV algorithms and emission factors measured in dynamometers and circulating vehicles in Argentina, Brazil, Chile and Colombia. Past emissions were back estimated from 2005 to 1970 using the best available information, which differs greatly among categories, spatial disaggregation and time periods. The time series of stationary and mobile combustion sources at the national and regional level allowed the identification of distinct patterns. National greenhouse gas emissions in 2006 amounted to ~ 150 million ton CO2-equivalent, 70% of which were contributed by stationary sources. On-road transport was the major contributor within mobile sources (28.1 %). The increasing emissions trends are dominated by on-road transport, agriculture and residential categories while the variability is largely associated with energy industries. National emissions of air pollutants were in the order: CO > NOx > HCNM > SO2. The small decrease in CO emissions of ~3% is associated with fuel switching from gasoline to compressed natural gas in road-transport, while the marked increase in SO2 emissions of ~34% can be linked to fuel switching from liquid fuels to natural gas in stationary combustion. With regards to regional emissions, mobile sources constitute the ‘high’ emitter. Our estimates for on-road mobile emissions point out the role of MABA and of the City of Buenos Aires as a concentrated site of pollutant emissions (ton CO km-2, year 2000): 0.7 (country-wise) << 122 (MABA) < 815 (CBA), being traffic the main source of pollutants in urban agglomerations.

Dawidowski, L.; Gomez, D.; Matranga, M.; D'Angiola, A.; Oreggioni, G.

2010-12-01

140

The composition of combustion products formed from gasoline-hydrogen-air mixtures in a constant-volume spherical chamber  

Microsoft Academic Search

The experimental unit, procedure for testing, and the results and reliability of the determination of the composition of combustion\\u000a products formed from gasoline-hydrogen-air (containing 0–100% hydrogen), gasoline-air, and isooctane-hydrogen-air mixtures\\u000a in a constant-volume chamber are described. Studies were performed at initial mixture temperatures of 20–70°C and a 0.1 MPa\\u000a pressure.

L. N. Bortnikov; D. A. Pavlov; M. M. Rusakov; A. P. Shaikin

2011-01-01

141

The combustion of high-velocity air-propane flow, initiated by a longitudinal-and-transverse DC discharge  

Microsoft Academic Search

Results are given of experimental investigations of the combustion of a supersonic air-propane flow, initiated by a longitudinal-and-transverse\\u000a dc discharge, in an aerodynamic channel with a backward-facing step. Several modes of combustion are revealed, which depend\\u000a on the initial conditions associated both with the discharge parameters such as current, duration and so on and with the parameters\\u000a of supersonic flow

A. P. Ershov; S. A. Kamenshchikov; A. A. Logunov; V. A. Chernikov

2009-01-01

142

Uncertainty for data with non-detects: Air toxic emissions from combustion  

SciTech Connect

Air toxic emission factor datasets often contain one or more points below a single or multiple detection limits and such datasets are referred to as 'censored.' Conventional methods used to deal with censored datasets include removing non-detects, replacing the censored points with zero, half of the detection limit, or the detection limit. However, the estimated means of the censored dataset by conventional methods are usually biased. Maximum likelihood estimation (MLE) and bootstrap simulation have been demonstrated as a statistically robust method to quantify variability and uncertainty of censored datasets and can provide asymptotically unbiased mean estimates. The MLE/bootstrap method is applied to 16 cases of censored air toxic emission factors, including benzene, formaldehyde, benzo(a)pyrene, mercury, arsenic, cadmium, total chromium, chromium VI and lead from coal, fuel oil, and/or wood waste external combustion sources. The proportion of censored values in the emission factor data ranges from 4 to 80%. Key factors that influence the estimated uncertainty in the mean of censored data are sample size and inter-unit variability. The largest range of uncertainty in the mean was obtained for the external coal combustion benzene emission factor, with 95 confidence interval of the mean equal to minus 93 to plus 411%.

Zhao, Y.C.; Frey, H.C. [CALTECH, Pasadena, CA (United States). Division of Chemical & Chemical Engineering

2006-12-15

143

Thermodynamic and transport combustion properties of hydrocarbons with air. Part 1: Properties in SI units  

NASA Technical Reports Server (NTRS)

Thermodynamic and transport combustion properties were calculated for a wide range of conditions for the reaction of hydrocarbons with air. Three hydrogen-carbon atom ratios (H/C = 1.7, 2.0, 2.1) were selected to represent the range of aircraft fuels. For each of these H/C ratios, combustion properties were calculated for the following conditions: Equivalence ratio: 0, 0.25, 0.5, 0.75, 1.0, 1.25 Water - dry air mass ratio: 0, 0.03 Pressure, kPa: 1.01325, 10.1325, 101.325, 1013.25, 5066.25 (or in atm: 0.01, 0.1, 1, 10, 50) Temperature, K: every 10 degrees from 200 to 900 K; every 50 degrees from 900 to 3000 K Temperature, R: every 20 degrees from 360 to 1600 R; very 100 degrees from 1600 to 5400 R. The properties presented are composition, density, molecular weight, enthalphy, entropy, specific heat at constant pressure, volume derivatives, isentropic exponent, velocity of sound, viscosity, thermal conductivity, and Prandtl number. Property tables are based on composites that were calculated by assuming both: (1) chemical equilibrium (for both homogeneous and heterogeneous phases) and (2) constant compositions for all temperatures. Properties in SI units are presented in this report for the Kelvin temperature schedules.

Gordon, S.

1982-01-01

144

Bus application of oxygen-enrichment technology and diesel-electric hybrid systems  

Microsoft Academic Search

The amendments to the Clean Air Act (CAA) mandate very strict limits on particulate, smoke, and other emissions from city buses. The use of alternative fuels, such as compressed natural gas (CNG) or methanol, can help transit operators, such as the Chicago Transit Authority (CTA), meet the mandated limits. However, the capital investment needed to convert the fueling infrastructure and

R. R. Sekar; W. W. Marr

1993-01-01

145

Projections of air toxic emissions from coal-fired utility combustion: Input for hazardous air pollutant regulators  

SciTech Connect

The US Environmental Protection Agency (EPA) is required by the 1990 CAAA to promulgate rules for all ``major`` sources of any of these HAPs. According to the HAPs section of the new Title III, any stationary source emitting 10 tons per year (TPY) of one HAP or 25 TPY of a combination of HAPs will be considered and designated a major source. In contrast to the original National Emission Standards for Hazardous Air Pollutants (NESHAP), which were designed to protect public health to ``an ample margin of safety,`` the new Title III, in its first phase, will regulate by industrial category those sources emitting HAPs in excess of the 10/25-TPY threshold levels, regardless of health risks. The trace elements normally associated with coal mineral matter and the various compounds formed during coal combustion have the potential to produce hazardous air toxic emissions from coal-fired electric utilities. Under Title III, the EPA is required to perform certain studies, prior to any regulation of electric utilities; these studies are currently underway. Also, the US Department of Energy (DOE) maintains a vested interest in addressing those energy policy questions affecting electric utility generation, coal mining, and steel producing critical to this country`s economic well-being, where balancing the costs to the producers and users of energy with the benefits of environmental protection to the workers and the general populace remains of significant concern.

Szpunar, C.B.

1993-08-01

146

Computer program for obtaining thermodynamic and transport properties of air and products of combustion of ASTM-A-1 fuel and air  

NASA Technical Reports Server (NTRS)

A computer program for determining desired thermodynamic and transport property values by means of a three-dimensional (pressure, fuel-air ratio, and either enthalpy or temperature) interpolation routine was developed. The program calculates temperature (or enthalpy), molecular weight, viscosity, specific heat at constant pressure, thermal conductivity, isentropic exponent (equal to the specific heat ratio at conditions where gases do not react), Prandtl number, and entropy for air and a combustion gas mixture of ASTM-A-1 fuel and air over fuel-air ratios from zero to stoichiometric, pressures from 1 to 40 atm, and temperatures from 250 to 2800 K.

Hippensteele, S. A.; Colladay, R. S.

1978-01-01

147

An analytical study of the hydrogen-air reaction mechanism with application to scramjet combustion  

NASA Technical Reports Server (NTRS)

A chemical kinetic mechanism for the combustion of hydrogen has been assembled and optimized by comparing the observed behavior as determined in shock tube and flame studies with that predicted by the mechanism. The reactions contained in the mechanism reflect the current state of knowledge of the chemistry of the hydrogen/air system, and the assigned rate coefficients are consistent with accepted values. It was determined that the mechanism is capable of satisfactorily reproducing the experimental results for a range of conditions relevant to scramjet combustion. Calculations made with the reaction mechanism for representative scramjet combustor conditions at Mach 8, 16, and 25 showed that chemical kinetic effects can be important and that combustor models which use nonequilibrium chemistry should be used in preference to models that assume equilibrium chemistry. For the conditions examined the results also showed the importance of including the HO2 chemistry in the mechanism. For Mach numbers less than 16, the studies suggest that an ignition source will most likely be required to overcome slow ignition chemistry. At Mach 25, the initial temperature and pressure was high enough that ignition was rapid and the presence of an ignition source did not significantly affect reaction rates.

Jachimowski, Casimir J.

1988-01-01

148

Review of Air Vitiation Effects on Scramjet Ignition and Flameholding Combustion Processes  

NASA Technical Reports Server (NTRS)

This paper offers a detailed review and analysis of more than 100 papers on the physics and chemistry of scramjet ignition and flameholding combustion processes, and the known effects of air vitiation on these processes. The paper attempts to explain vitiation effects in terms of known chemical kinetics and flame propagation phenomena. Scaling methodology is also examined, and a highly simplified Damkoehler scaling technique based on OH radical production/destruction is developed to extrapolate ground test results, affected by vitiation, to flight testing conditions. The long term goal of this effort is to help provide effective means for extrapolating ground test data to flight, and thus to reduce the time and expense of both ground and flight testing.

Pellett, G. L.; Bruno, Claudio; Chinitz, W.

2002-01-01

149

Heat transfer and pressure distributions on hemisphere-cylinders in methane-air combustion products at Mach 7  

NASA Technical Reports Server (NTRS)

Heat-transfer and pressure distributions were measured over the surfaces of three hemisphere-cylinder models tested at a nominal Mach number of 7 in the Langley 8-foot high-temperature structures tunnel which uses methane-air products of combustion as a test medium. The results showed that the heat-transfer and pressure distributions over the surface of the models were in good agreement with experimental data obtained in air and also with theoretical predictions.

Weinstein, I.

1973-01-01

150

Extinguishment of methane diffusion flames by inert gases in coflow air and oxygen-enriched microgravity environments  

Microsoft Academic Search

Extinguishment of laminar coflow diffusion flames in microgravity (?g) have been studied experimentally and computationally. The ?g experiments were conducted using a methane cup-burner flame aboard the NASA Reduced-Gravity Aircraft. Transient computations with full methane chemistry and a gray-gas radiation model were performed to reveal the flame structure and extinguishment processes. In ?g, as an inert gas (N2, He, or

Fumiaki Takahashi; Gregory T. Linteris; Viswanath R. Katta

2011-01-01

151

Pressure distribution and heat exchange in a gasdynamic model with combustion over which a high-enthalpy air stream flows  

Microsoft Academic Search

In [I-3], on gasdynamic models with combustion in high-enthalpy oncoming air, we obtained the force characteristics, determined the completeness of hydrogen burning made a comparison of experimental and calculated data, and developed a physical picture of the flow in the internal channels of the models. The purpose of [I-3] was an investigation primarily of the total effect from hydrogen burning:

V. K. Baev; V. V. Shumskii; M. I. Yaroslavtsev

1985-01-01

152

A New Type of Steady and Stable, Laminar, Premixed Flame in Ultra-Lean, Hydrogen-Air Combustion  

E-print Network

A New Type of Steady and Stable, Laminar, Premixed Flame in Ultra-Lean, Hydrogen-Air Combustion of laminar flame that is steady and stable beside flat flames and flame balls. Direct numerical simulations are performed of flames that develop into steadily and stably propagating cells. These cells were the original

Geddes, Cameron Guy Robinson

153

Combustion Air Preheat and Radiant Heat Transfer in Fired Heaters - A Graphical Method for Design and Operating Analysis  

E-print Network

heat transfer efficiency thereby enabling the transfer of the same amount of energy from a lower total heat release in the radiant box. This paper presents a graphical procedure that can be used (1) to estimate fuel savings obtained by combustion air...

Grantom, R. L.

1981-01-01

154

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

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. PMID:24887118

Ochoa-González, Raquel; Díaz-Somoano, Mercedes; Martínez-Tarazona, M Rosa

2014-07-15

155

Ab initio atomistic thermodynamics study on the sulfur tolerance mechanism of the oxygen-enriched yttria-stabilized zirconia surface  

NASA Astrophysics Data System (ADS)

The first-principles method based on density functional theory (DFT) is used to investigate the reaction mechanism for the adsorption of H2S on the oxygen-enriched yttria-stabilized zirconia (YSZ + O) (111) surface. It is found that the H2S dissociation processes have low energy barriers (< 0.5 eV) and high exothermicities (2.5 eV), and the dissociative S atoms may result in the poisoning of the YSZ + O surface by forming the SO and the hyposulfite (SO22 -) species with very strong bonds to the surface. In addition, using the ab initio atomistic thermodynamics method, the surface regeneration or de-sulfurization process of a sulfur-poisoned (i.e. sulfur-covered) YSZ + O(111) surface is studied. According to the phase diagram, the adsorbed atomic sulfur can be oxidized to SO2 and removed from the YSZ + O surface by introducing oxidizing reagents, e.g. O2 and H2O.

Chu, Xingli; Zhang, Yanxing; Li, Shasha; Yang, Zongxian

2014-04-01

156

Hybrid membrane--PSA system for separating oxygen from air  

DOEpatents

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.

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

2011-01-25

157

Operation regimes in catalytic combustion: H{sub 2}/air mixtures near Pt  

SciTech Connect

The influence of a platinum catalyst on flammability limits and operation windows for catalytic and catalyst-assisted homogeneous oxidation is studied, for the first time to the authors` knowledge, as a function of H{sub 2} in air composition in a stagnation-point flow geometry. The results show that the coupling between the homogeneous and heterogeneous chemistries leads to relatively easy startup, the coexistence of catalytically (partially) and homogeneously (completely) ignited branches under certain conditions, and the expansion of the fuel-lean and rich flammability limits. A strategy to attain virtually any desired operation regime is discussed. It is shown that synergism between homogeneous and heterogeneous chemistries leads to higher combustion efficiency and lower fuel emissions at elevated temperatures for fuel-lean mixtures only. Analysis of the flammability limits indicates that heat generated by surface reactions is primarily responsible for expansion of the flammability limits. Finally, a direct transition to flames occurs over a wide range of composition upon catalytic ignition in the absence of surface heat loss.

Park, Y.K.; Bui, P.A.; Vlachos, D.G. [Univ. of Massachusetts, Amherst, MA (United States). Dept. of Chemical Engineering] [Univ. of Massachusetts, Amherst, MA (United States). Dept. of Chemical Engineering

1998-09-01

158

A New Type of Steady and Stable, Laminar, Premixed Flame in Ultra-Lean, Hydrogen-Air Combustion  

SciTech Connect

Ultra-lean, hydrogen-air mixtures are found to support another kind of laminar flame that is steady and stable beside flat flames and flame balls. Direct numerical simulations are performed of flames that develop into steadily and stably propagating cells. These cells were the original meaning of the word"flamelet'' when they were observed in lean flammability studies conducted early in the development of combustion science. Several aspects of these two-dimensional flame cells are identified and are contrasted with the properties of one-dimensional flame balls and flat flames. Although lean hydrogen-air flames are subject to thermo-diffusive effects, in this case the result is to stabilize the flame rather than to render it unstable. The flame cells may be useful as basic components of engineering models for premixed combustion when the other types of idealized flames are inapplicable.

Grcar, Joseph F; Grcar, Joseph F

2008-06-30

159

Pyrolysis and Combustion Behavior of Ternary Fuel Blends in Air and Oxy-Fuel Conditions by Using TGA-FTIR  

Microsoft Academic Search

Pyrolysis and combustion tests of imported coal, an indigenous lignite, petcoke, and their 60\\/30\\/10 wt.% ternary blends were carried out in air and oxy-fuel conditions by using thermogravimetry analysis–Fourier transform infrared (TGA-FTIR). Pyrolysis results of the blend and its parent fuels show that weight loss profiles display similar trends up to 700 °C in both nitrogen and carbon dioxide atmospheres. However,

N. S. Yüzba??; N. Selçuk

2012-01-01

160

Higher borides and oxygen-enriched Mg–B–O inclusions as possible pinning centers in nanostructural magnesium diboride and the influence of additives on their formation  

Microsoft Academic Search

The study of high pressure (2GPa) synthesized MgB2-based materials allows us to conclude that higher borides (with near MgB12 stoichiometry) and oxygen-enriched Mg–B–O inclusions can be pinning centers in nanostructural magnesium diboride matrix (with average grain sizes of 15–37nm). It has been established that additions of Ti or SiC as well as manufacturing temperature can affect the size, amount and

Tatiana Prikhna; Wolfgang Gawalek; Yaroslav Savchuk; Vasiliy Tkach; Nikolay Danilenko; Michael Wendt; Jan Dellith; Harold Weber; Michael Eisterer; Viktor Moshchil; Nina Sergienko; Artem Kozyrev; Peter Nagorny; Andrey Shapovalov; Vladimir Melnikov; Sergey Dub; Doris Litzkendorf; Tobias Habisreuther; Christa Schmidt; Athanasios Mamalis; Vladimir Sokolovsky; Vladimir Sverdun; Fridrich Karau; Alexandra Starostina

2010-01-01

161

MERCURY AND AIR TOXIC ELEMENT IMPACTS OF COAL COMBUSTION BY-PRODUCT DISPOSAL AND UTILIZATION  

SciTech Connect

On April 3, 2003, a project kickoff meeting was held at the U.S. Department of Energy National Energy Technology Laboratory. As a result of this meeting and follow-up communications, a final work plan was developed, and a schedule of laboratory tasks was developed. Work for the remainder of the second quarter of this project focused on sample collection, initiating laboratory tests, and performing literature searchers. The final project partner, the North Dakota Industrial Commission, signed its contract for participation in the project. This effort will focus on the evaluation of coal combustion by-products (CCBs) for their potential to release mercury and other air toxic elements under different controlled laboratory conditions and will investigate the release of these same air toxic elements in select disposal and utilization field settings to understand the impact of various emission control technologies. The information collected will be evaluated and interpreted together with past Energy & Environmental Research Center (EERC) data and similar data from other studies. Results will be used to determine if mercury release from CCBs, both as currently produced and produced with mercury and other emission controls in place, is a realistic environmental issue. The proposed work will evaluate the impact of mercury and other air toxics on the disposal and/or utilization of CCBs. The project will provide data on the environmental acceptability of CCBs expected to be produced in systems with emission controls for typical disposal and utilization scenarios. The project will develop baseline information on release mechanisms of select elements in both conventional CCBs and modified or experimental CCBs. The modified or experimental CCBs will be selected to represent CCBs from systems that have improved emission controls. Controlling these emissions has high potential to change the chemical characteristics and environmental performance of CCBs. Development of reliable methods to determine the release of mercury from CCBs will provide a means of evaluating the environmental risk associated with CCB management practices. Using appropriate methods to develop a data set of currently produced CCBs and CCBs produced under experimental/simulated conditions will provide a baseline for the CCB industry to understand the impact of various emission control technologies.

Debra F. Pflughoeft-Hassett

2003-07-01

162

Mercury and Air Toxic Element Impacts of Coal Combustion By-Product Disposal and Utilizaton  

SciTech Connect

The University of North Dakota Energy & Environmental Research Center (EERC) conducted a multiyear study to evaluate the impact of mercury and other air toxic elements (ATEs) on the management of coal combustion by-products (CCBs). The ATEs evaluated in this project were arsenic, cadmium, chromium, lead, nickel, and selenium. The study included laboratory tasks to develop measurement techniques for mercury and ATE releases, sample characterization, and release experiments. A field task was also performed to measure mercury releases at a field site. Samples of fly ash and flue gas desulfurization (FGD) materials were collected preferentially from full-scale coal-fired power plants operating both without and with mercury control technologies in place. In some cases, samples from pilot- and bench-scale emission control tests were included in the laboratory studies. Several sets of 'paired' baseline and test fly ash and FGD materials collected during full-scale mercury emission control tests were also included in laboratory evaluations. Samples from mercury emission control tests all contained activated carbon (AC) and some also incorporated a sorbent-enhancing agent (EA). Laboratory release experiments focused on measuring releases of mercury under conditions designed to simulate CCB exposure to water, ambient-temperature air, elevated temperatures, and microbes in both wet and dry conditions. Results of laboratory evaluations indicated that: (1) Mercury and sometimes selenium are collected with AC used for mercury emission control and, therefore, present at higher concentrations than samples collected without mercury emission controls present. (2) Mercury is stable on CCBs collected from systems both without and with mercury emission controls present under most conditions tested, with the exception of vapor-phase releases of mercury exposed to elevated temperatures. (3) The presence of carbon either from added AC or from unburned coal can result in mercury being sorbed onto the CCB when exposed to ambient-temperature air. The environmental performance of the mercury captured on AC used as a sorbent for mercury emission control technologies indicated that current CCB management options will continue to be sufficiently protective of the environment, with the potential exception of exposure to elevated temperatures. The environmental performance of the other ATEs investigated indicated that current management options will be appropriate to the CCBs produced using AC in mercury emission controls.

David Hassett; Loreal Heebink; Debra Pflughoeft-Hassett; Tera Buckley; Erick Zacher; Mei Xin; Mae Sexauer Gustin; Rob Jung

2007-03-31

163

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

NASA Technical Reports Server (NTRS)

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.

Carson, G. T., Jr.

1974-01-01

164

Development of Electrophoretic Process for Coating T-53 Air Diffuser, Exhaust Diffuser, and Combustion Chamber Housing with 'Sermetel W' (Trade Name).  

National Technical Information Service (NTIS)

The report covers activities accomplished to develop an electrophoretic coating method for the application of 'SERMETEL W' to all critical surfaces of the exhaust diffuser, air diffuser and combustion chamber housing of the T-53 engine. 'SERMETEL W' has b...

K. A. Gebler

1967-01-01

165

Numerical Investigation of Fuel Dilution Effects on the Performance of the Conventional and the Highly Preheated and Diluted Air Combustion Furnaces  

Microsoft Academic Search

This numerical study investigates the effects of using a diluted fuel (50% natural gas and 50% N2) in an industrial furnace under several cases of conventional combustion (air with 21% O2 at 300 and 1273 K) and the highly preheated and diluted air (1273 K with 10% O2 and 90% N2) combustion (HPDAC) conditions using an in-house computer program. It

Kiomars Abbasi Khazaei; Ali Asghar Hamidi; Masoud Rahimi

2009-01-01

166

CHARACTERIZATION OF AIR EMISSIONS FROM THE SIMULATED OPEN COMBUSTION OF FIBERGLASS MATERIALS  

EPA Science Inventory

The report identifies and quantifies a broad range of pollutants that are discharged during small-scale, simulated, open combustion of fiberglass, and reports these emissions relative to the mass of fiberglass material combusted. Two types of fiberglass materials (representing t...

167

CHARACTERIZATION OF AIR EMISSIONS FROM THE SIMULATED OPEN COMBUSTION OF FIBERGLASS MATERIALS  

EPA Science Inventory

The report identifies and quantifies a broad range of pollutants that are discharged during small-scale, simulated, open combustion of fiberglass, and reports these emissions relative to the mass of fiberglass material combusted. wo types of fiberglass materials (representing the...

168

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)

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.

Kelly, H. N.; Wieting, A. R.

1984-01-01

169

Experimental study on premixed CH{sub 4}/air mixture combustion in micro Swiss-roll combustors  

SciTech Connect

Excess enthalpy combustion is a promising approach to stabilize flame in micro-combustors. Using a Swiss-roll combustor configuration, excess enthalpy combustion can be conveniently achieved. In this work, three types of Swiss-roll combustors with double spiral-shaped channels were designed and fabricated. The combustors were tested using methane/air mixtures of various equivalence ratios. Both temperature distributions and extinction limits were determined for each combustor configuration at different methane mass flow rates. Results indicate that the Swiss-roll combustors developed in the current study greatly enhance combustion stability in center regions of the combustors. At the same time, excess enthalpy combustors of the Swiss-roll configuration significantly extend the extinction limits of methane/air mixtures. In addition, the effects of combustor configurations and thermal insulation arrangements on temperature distributions and extinction limits were evaluated. With heat losses to the environment being significant, the use of thermal insulations further enhances the flame stability in center regions of the Swiss-roll combustors and extends flammable ranges. (author)

Zhong, Bei-Jing; Wang, Jian-Hua [Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Engineering Mechanics, Tsinghua University, Beijing 100084 (China)

2010-12-15

170

Combustion control  

Microsoft Academic Search

This patent describes an improved method of operating in a combustion process which is regulated by maintaining a preselected feed forward relationship of fuel input and air input. It comprises: establishing a fuel\\/air input peak relationship for the approximately stoichiometric condition which produces the maximum infrared radiation; selecting a desired operating fuel\\/air ratio based on a result of the fuel\\/air

Zabielski

1990-01-01

171

NO emission of oxygen-enriched CH 4\\/O 2\\/N 2 premixed flames under electric field  

Microsoft Academic Search

This work investigates the electric field effect on nitrogen oxide (NO) pollutant formation and emission composition of premixed flames in order to provide better insight on the mechanism of controlling the combustion process by electro-physical means. The present study aims to investigate experimentally the effect of radial DC electric field on premixed laminar methane flame. The electric field effect on

Eugene V. Vega; Sung Su Shin; Ki Yong Lee

2007-01-01

172

Model test on underground coal gasification (UCG) with low-pressure fire seepage push-through. Part I: Test conditions and air fire seepage  

SciTech Connect

The technology of a pushing-through gallery with oxygen-enriched fire-seepage combustion was studied during shaft-free UCG in this article, and the main experiment parameters were probed. The test results were analyzed in depth. The patterns of variation and development were pointed out for the fire source moving speed, temperature field, leakage rate, the expanding diameter for the gasification gallery, and blasting pressure. Test results showed that, with the increase in the wind-blasting volume, the moving velocity for the fire source speeded up, and the average temperature for the gallery continuously rose. Under the condition of oxygen-enriched air blasting, when O{sub 2} contents stood at 90%, the moving speed for the fire source was 4-5 times that of air blasting. In the push-through process, the average leakage rate for the blasting was 82.23%, with the average discharge volume of 3.43 m{sup 3}/h and average gallery diameter of 7.87 cm. With the proceeding of firepower seepage, the extent of dropping for the leakage rate increased rapidly, and the drop rate for the blasting pressure gradually heightened.

Yang, L.H. [China University of Mining & Technology, Xuzhou (China)

2008-07-01

173

Higher borides and oxygen-enriched Mg-B-O inclusions as possible pinning centers in nanostructural magnesium diboride and the influence of additives on their formation  

NASA Astrophysics Data System (ADS)

The study of high pressure (2 GPa) synthesized MgB 2-based materials allows us to conclude that higher borides (with near MgB 12 stoichiometry) and oxygen-enriched Mg-B-O inclusions can be pinning centers in nanostructural magnesium diboride matrix (with average grain sizes of 15-37 nm). It has been established that additions of Ti or SiC as well as manufacturing temperature can affect the size, amount and distribution of these inclusions in the material structure and thus, influence critical current density. The superconducting behavior of materials with near MgB 12 stoichiometry of matrix is discussed.

Prikhna, Tatiana; Gawalek, Wolfgang; Savchuk, Yaroslav; Tkach, Vasiliy; Danilenko, Nikolay; Wendt, Michael; Dellith, Jan; Weber, Harold; Eisterer, Michael; Moshchil, Viktor; Sergienko, Nina; Kozyrev, Artem; Nagorny, Peter; Shapovalov, Andrey; Melnikov, Vladimir; Dub, Sergey; Litzkendorf, Doris; Habisreuther, Tobias; Schmidt, Christa; Mamalis, Athanasios; Sokolovsky, Vladimir; Sverdun, Vladimir; Karau, Fridrich; Starostina, Alexandra

2010-10-01

174

Development of the utilization of combustible gas produced in existing sanitary landfills: Investigation of effects of air inclusion  

NASA Astrophysics Data System (ADS)

The effects of nitrogen and oxygen on landfill gas operations are discussed. A combustible gas mixture composed of methane and carbon dioxide is generated in municipal solid waste landfills. A consequence of the collection of this fuel gas is the inclusion of some air in the collected product. The effects include increased collected and purification costs, reduction in the quality of the fuel gas produced, corrosion, explosion hazards, and interference with odorant systems. The scope of such effects was determined by using landfill data of a gas recovery site as a basis. Useful supplemental fuel gas may be recovered despite the inclusion of air. Recommendations are made for establishing limits for nitrogen and oxygen content and minimizing the costs associated with their presence.

1983-01-01

175

Effects of percentage of blockage and flameholder downstream counterbores on lean combustion limits of premixed, prevaporized propane-air mixture  

NASA Technical Reports Server (NTRS)

Lean combustion limits were determined for a premixed prevaporized propane air mixture with flat plate flame stabilizers. Experiments were conducted in a constant area flame tube combustor utilizing flameholders of varying percentages of blockage and downstream counterbores. Combustor inlet air velocity at ambient conditions was varied from 4 to 9 meters per second. Flameholders with a center hole and four half holes surrounding it were tested with 63, 73, and 85 percent blockage and counterbore diameters of 112 and 125 percent of the thru hole diameter, in addition to the no counterbore configuration. Improved stability was obtained by using counterbore flameholders and higher percentages of blockage. Increases in mixture velocity caused the equivalence ratio at blowout to increase in all cases.

Fernandez, M. A. B.

1983-01-01

176

Health effects of air pollution due to coal combustion in the Chestnut Ridge Region of Pennsylvania: results of cross-sectional analysis in adults  

Microsoft Academic Search

Respiratory questionnaires (ATS-DLD-78) were administered to 5557 adult women in a rural area of Western Pennsylvania to evaluate the health effects of air pollution resulting from coal combustion. Air pollution data were derived from 17 air quality monitor sites and stratified to define low, medium, and high pollution areas. The means of 4 yr (1975-1978) annual averages for sulfur dioxide

M. B. Schenker; F. E. Speizer; J. M. Samet; J. Gruhl; S. Batterman

2009-01-01

177

76 FR 12923 - National Emission Standards for Hazardous Air Pollutants for Reciprocating Internal Combustion...  

Federal Register 2010, 2011, 2012, 2013

...telephone number for the Air Docket is (202) 566-1742...National Technology Transfer and Advancement Act...through the Technology Transfer Network Web site (TTN Web...exchange in various areas of air pollution...

2011-03-09

178

Numerical simulation of air and oxy-fuel combustion of single coal particles using the reactive implicit continuous-fluid Eulerian (RICE) method  

NASA Astrophysics Data System (ADS)

The paper presents the mathematical model of air and oxy-fuel combustion of single coal particles. The combustion process has been treated as a spherically-symmetric one. The 1-dimensional time-dependent conservation equations governing the process have been numerically solved using the RICE method. The presence of a coal particle, which was treated as a discrete Lagrange particle, has modified the boundary conditions at the gas-solid interface. Numerical results show good agreement with the experimental results.

Lewtak, Robert

2013-10-01

179

CHARACTERIZATION OF INCIDENTAL CARBONACEOUS NANOPARTICLES IN AMBIENT AIR AND COMBUSTION EXHAUST  

EPA Science Inventory

The most important result of this research is one of the most complete datasets to date on the presence of C60 in the aerosol phase in the natural environment. This study expects that C60 fullerenes will not be found at detectable levels in combustion exhaust, ambient carbo...

180

ENVIRONMENTAL CONTROL OF TOXIC METAL AIR EMISSIONS FROM THE COMBUSTION OF COAL AND WASTES  

EPA Science Inventory

The paper is concerned with the partitioning of toxic metals (e.g., arsenic, selenium, mercury, chromium, lead, and cadmium) during combustion, and with the mitigation of their effect on the environment using high-temperature sorbents. The paper is divided into three parts: (1) t...

181

Quantitative Analysis of Spectral Interference of Spontaneous Raman Scattering in High-Pressure Fuel-Rich H2-Air Combustion  

NASA Technical Reports Server (NTRS)

We present a theoretical study of the spectral interferences in the spontaneous Raman scattering spectra of major combustion products in 30-atm fuel-rich hydrogen-air flames. An effective methodology is introduced to choose an appropriate line-shape model for simulating Raman spectra in high-pressure combustion environments. The Voigt profile with the additive approximation assumption was found to provide a reasonable model of the spectral line shape for the present analysis. The rotational/vibrational Raman spectra of H2, N2, and H2O were calculated using an anharmonic-oscillator model using the latest collisional broadening coefficients. The calculated spectra were validated with data obtained in a 10-atm fuel-rich H2-air flame and showed excellent agreement. Our quantitative spectral analysis for equivalence ratios ranging from 1.5 to 5.0 revealed substantial amounts of spectral cross-talk between the rotational H2 lines and the N2 O-/Q-branch; and between the vibrational H2O(0,3) line and the vibrational H2O spectrum. We also address the temperature dependence of the spectral cross-talk and extend our analysis to include a cross-talk compensation technique that removes the nterference arising from the H2 Raman spectra onto the N2, or H2O spectra.

Kojima, Jun; Nguyen, Quang-Viet

2004-01-01

182

Influence Analysis of Air Flow Momentum on Concentrate Dispersion and Combustion in Copper Flash Smelting Furnace by CFD Simulation  

NASA Astrophysics Data System (ADS)

The Outokumpu flash smelting process is a very successful technology for copper extraction from sulfide concentrate. Numerical simulation has been used for several decades in the analysis and evaluation of the smelting process. However, significant delay in the particle ignition was found in computations of flash furnaces that had great expansion in their productivity. A study was thereafter carried out to investigate how the gaseous flows influence the particle dispersion and combustion. A momentum ratio was defined to describe the effective portion of the pressure forces caused by the lateral and the vertical gaseous flows. Simulations were carried out with Fluent 6.3 (Fluent Inc. The software package is now known as Ansys Fluent of Ansys Inc.) for cases with different momentum ratios as well as of the same momentum value. A detailed analysis and discussion of influences of the gaseous momentum on the particle dispersion are presented. The result reveals that a large momentum ratio combined with large amount of distribution air is helpful for good particle dispersions and thus quicker combustions. Also the process air is found to perform a constraint influence on the particle dispersions, particularly for those of medium and small sizes.

Zhou, Jun; Zhou, Jieming; Chen, Zhuo; Mao, Yongning

2014-09-01

183

Spatially and Temporally Resolved Measurements of Velocity in a H2-air Combustion-Heated Supersonic Jet  

NASA Technical Reports Server (NTRS)

This paper presents simultaneous measurements at multiple points of two orthogonal components of flow velocity using a single-shot interferometric Rayleigh scattering (IRS) technique. The measurements are performed on a large-scale Mach 1.6 (Mach 5.5 enthalpy) H2-air combustion jet during the 2007 test campaign in the Direct Connect Supersonic Combustion Test facility at NASA Langley Research Center. The measurements are performed simultaneously with CARS (Coherent Anti-stokes Raman Spectroscopy) using a combined CARS-IRS instrument with a common path 9-nanosecond pulsed, injection-seeded, 532-nm Nd:YAG laser probe pulse. The paper summarizes the measurements of velocities along the core of the vitiated air flow as well as two radial profiles. The average velocity measurement near the centerline at the closest point from the nozzle exit compares favorably with the CFD calculations using the VULCAN code. Further downstream, the measured axial velocity shows overall higher values than predicted with a trend of convergence at further distances. Larger discrepancies are shown in the radial profiles.

Bivolaru, Daniel; Cutler, Andrew D.; Danehy, Paul M.; Gaffney, Richard L.; Baurle, Robert a.

2009-01-01

184

Exposure risk to carcinogenic PAHs in indoor-air during biomass combustion whilst cooking in rural India  

NASA Astrophysics Data System (ADS)

In India, a vast majority of rural household burns unprocessed biomass, as an energy source, to cook food. The biomass is burnt indoors in conventionally homemade clay-stoves, called 'Chulha', which results in the generation of a variety of airborne products along with polycyclic aromatic hydrocarbons (PAHs) in an uncontrolled manner. We report here the concentrations and profile of carcinogenic PAHs, co-sampled with respirable suspended particulate matter, in rural indoors during burning of biomass vis-à-vis liquified petroleum gas as the energy source. There is a limited data on the subject in the literature. The seasonal variation has also been studied. Sampling was done in breathing zone and in surrounding areas concurrent with cooking on chulha. PAHs were extracted in methylene chloride and analyzed over HPLC after column clean up on silica gel. Our study revealed that the concentrations of carcinogenic PAHs were fairly high in breathing zone and in surrounding areas while cooking over chulha in rural India. PAHs concentrations increased substantially during biomass combustion. Concentrations were high during CDC combustion and low during LPG combustion or the non-cooking period. This trend was conserved in both the seasons. Concentrations of total PAHs were greater in winter as compared to summer and greatest in the breathing zone. Di-benz( a,h)anthracene, benzo( k)-fluoranthene and chrysene contributed maximum. Benzo( a)pyrene contributed moderately. Maximum concentrations of indoor air benzo( a)pyrene (>1.5 ?g/m 3) were found in breathing zone in winter. The daily exposure to high concentrations of carcinogenic PAHs in indoor air environment while cooking food could be impacting for chronic pulmonary illnesses in rural Indian women.

Bhargava, Anuj; Khanna, R. N.; Bhargava, S. K.; Kumar, Sushil

185

Air toxics evaluation of ABB Combustion Engineering Low-Emission Boiler Systems  

SciTech Connect

The specific goals of the program are to identify air toxic compounds that might be emmitted from the new boiler with its various Air Pollution Control device for APCD alternatives in levels of regulatory concern. For the compounds thought to be of concern, potential air toxic control methodologies will be suggested and a Test Protocol will be written to be used in the Proof of Concept and full scale tests. The following task was defined: Define Replations and Standards; Identify Air Toxic Pollutants of Interest to Interest to Utility Boilers; Assesment of Air Toxic By-Products; State of the Art Assessment of Toxic By-Product Control Technologies; and Test Protocol Definition.

Wesnor, J.D. [ABB/Combustion Engineering, Inc., Windsor, CT (United States)

1993-10-26

186

Effects of EGR, water/N2/CO2 injection and oxygen enrichment on the availability destroyed due to combustion for a range of conditions and fuels  

E-print Network

................................................................................................................. xiii I INTRODUCTION.................................................................................................... 1 Availability or Exergy................................................................................... 1 Description... and aims at quantifying the availability that is lost. Availability or Exergy Availability or Exergy represents the work potential of any system as it comes into equilibrium with the environment. No system can extract work greater than...

Sivadas, Hari Shanker

2009-06-02

187

Operation and maintenance of DOE/PETC Combustion Test Facilities. Final activity report, December 20, 1982-January 18, 1985  

SciTech Connect

On December 20, 1982, Management and Technical Services Company/General Electric (MATSCO/GE) began to operate, modify and maintain the Combustion Test Facilities at the Pittsburgh Energy Technology Center (PETC). The work is divided into three main programs: Alternate Fuels/In-House Research, Flue Gas Cleanup Research and Development, and Advanced Research and Technology Development. The objectives of the initial programs were to (1) retrofit the boilers with minimum modifications; (2) prepare CWM with coal concentrations that result in acceptable mixing, handling, and transport characteristics; (3) achieve stable CWM flames in boilers without supplemental fuel assistance; and (4) establish CWM combustion characteristics. In the 700-HP CTF, investigations into the effects on combustion of methanol addition, coal particle size, and oxygen enrichment of the combustion air were pursued, as well as evaluation of various burners, reduction of NO/sub x/ emissions through the introduction of staged air, and evaluation of anthracite CWM combustion. Work at the 100-HP CTF focused on investigation of coal particle size, use of various coal and petroleum by-products, the effects of long-term ash deposition in the boiler, and new burner nozzle adaptations. In December, 1983, MATSCO/GE assumed responsibilities of operation, modification, and maintenance of the Coal-Fired Flue Gas Cleanup Test Facility. The Dry Combined Flue Gas Cleanup PDU was completely built and shaken down, and formal testing of lime slurry injection into the flue gas for SO/sub 2//NO/sub x/ reduction was initiated. In the Copper Oxide Continuous Life Cycle PDU, construction of the furnace was completed and construction of the absorber and regenerator units was begun. 15 figs., 10 tabs.

Not Available

1985-01-01

188

Estimation of Fuel Savings by Recuperation of Furnace Exhausts to Preheat Combustion Air  

E-print Network

EXHAUST MEI'HANE BURNER FURNACE .. GAS 'ID hv ST.ACK J) 1 I J) -I ] d) AIR 77?F Figure 1 System :Schmatic l'Tithout Recuperator cp JI1E'rHANER-"'Y--".~1 BURNER FURNACE AIR .c-....-.... EXHAUST GA~ 'ID STibHANE BURNER FURNACE .. GAS 'ID hv ST.ACK J) 1 I J) -I ] d) AIR 77?F Figure 1 System :Schmatic l'Tithout Recuperator cp JI1E'rHANER-"'Y--".~1 BURNER FURNACE AIR .c-....-.... EXHAUST GA~ 'ID STib< Figure 2 System Schematic...

Rebello, W. J.; Kohnken, K. H.; Phipps, H. R., Jr.

1980-01-01

189

Air-cooled type intercooler for a supercharged internal combustion engine  

SciTech Connect

A vehicle is described comprising an engine room having a radiator grille at a front end, an engine room hood lock support at a position behind the radiator grille, a bumper located below the radiator grille, and an air dam skirt located below the bumper. A transversely extending chamber-like space is formed between the radiator grille, the hood lock support, the bumper and the air dam skirt. An engine body is provided within the engine room. A supercharging system is in fluid communication with the engine body. The supercharging system comprises a pair of turbochargers arranged in parallel. An intercooler is provided in the chamber-like space. The cooler comprises an inlet tank in fluid communication with the supercharger system for receiving compressed air therefrom, an outlet tank in fluid communication with the engine body for introducing cool air into the engine body, and a radiator core arranged between the inlet tank and the outlet rank. The radiator core comprises horizontally juxtaposed and vertically extending heat exchanger pipes between which air can pass in order to cool compressed air in the heat exchanger pipes. The radiator core has a length in the horizontal direction which is greater than a height of the radiator core in the vertical direction. The air passing over the air dam skirt, below the bumper, is directed onto the vertically extending heat exchanger pipes of the intercooler.

Saito, T.; Kotani, A.

1987-10-27

190

75 FR 9647 - National Emission Standards for Hazardous Air Pollutants for Reciprocating Internal Combustion...  

Federal Register 2010, 2011, 2012, 2013

...with the start of fuel flow to the engine and ends...operating temperature and air to fuel flows as indicated by the manufacturers...a catalyst is used to control emissions; startup does...happen before the engine air and fuel flows are normal and thus...

2010-03-03

191

CONTROL OF AIR EMISSIONS FROM HAZARDOUS WASTE COMBUSTION SOURCES: FIELD EVALUATIONS OF PILOT-SCALE AIR POLLUTION CONTROL DEVICES  

EPA Science Inventory

Pilot scale air pollution control devices supplied by Hydro-Sonic Systems, ETS, Inc., and Vulcan Engineering Company were installed at the ENSCO, Inc. Incinerator in El Dorado, Arkansas, in the spring of 1984. Each of these units treated an uncontrolled slipstream of the incinera...

192

Reduction of the NOx emission of a closed combustion chamber by changing to air flows with swirl  

Microsoft Academic Search

From a study of NOx production in flames it follows that NOx emission differs for various combustion chambers. In addition to increasing the combustion chamber temperature or the volume flow into the combustion chamber, it is essential to find another way of reducing the production of NOx in the combustion process. In this paper the effect of swirl on NOx

R. Hatami

1981-01-01

193

Combustion Tests of Rocket Motor Washout Material: Focus on Air toxics Formation Potential and Asbestos Remediation  

SciTech Connect

The objective of this investigation is to determine the suitability of cofiring as a recycle / reuse option to landfill disposal for solid rocket motor washout residue. Solid rocket motor washout residue (roughly 55% aluminum powder, 40% polybutadiene rubber binder, 5% residual ammonium perchlorate, and 0.2-1% asbestos) has been fired in Sandia's MultiFuel Combustor (MFC). The MFC is a down-fired combustor with electrically heated walls, capable of simulating a wide range of fuel residence times and stoichiometries. This study reports on the fate of AP-based chlorine and asbestos from the residue following combustion.

G. C. Sclippa; L. L. Baxter; S. G. Buckley

1999-02-01

194

Experimental investigation of pressure and blockage effects on combustion limits in H{sub 2}-air-steam mixtures  

SciTech Connect

Experiments with hydrogen-air-steam mixtures, such as those found within a containment system following a reactor accident, were conducted in the Heated Detonation Tube (43 cm diameter and 12 m long) to determine the region of benign combustion; i.e., the region between the flammability limits and the deflagration-to-detonation transition limits. Obstacles were used to accelerate the flame; these include 30% blockage ratio annular rings, and alternate rings and disks of 60% blockage ratio. The initial conditions were 110 {degree}C and one or three atmospheres pressure. A benign burning region exists for rich mixtures, but is generally smaller than for lean mixtures. Effects of the different obstacles and of the different pressures are discussed.

Sherman, M.P.; Berman, M. [Sandia National Labs., Albuquerque, NM (United States); Beyer, R.F. [Westinghouse Electric Corp., Pittsburgh, PA (US)

1993-06-01

195

The promising chemical kinetics for the simulation of propane-air combustion with KIVA-II code  

NASA Technical Reports Server (NTRS)

The development of chemical kinetics for the simulation of propane-air combustion with the use of computer code KIVA-II since 1989 is summarized here. In order to let readers understand the general feature well, a brief description of the KIVA-II code, specially related with the chemical reactions is also given. Then the results of recent work with 20 reaction mechanism is presented. It is also compared with the 5 reaction mechanism. It may be expected that the numerical stability of the 20 reaction mechanism is better as compared to that of 5 reaction mechanism, but the CPU time of the CRAY computer is much longer. Details are presented in the paper.

Ying, S. J.; Gorla, Rama S. R.; Kundu, Krishna P.

1993-01-01

196

VITRIFICATION OF MUNICIPAL SOLID WASTE COMBUSTION AIR POLLUTION CONTROL RESIDUES USING CORNING, INC. PROCESS  

EPA Science Inventory

A demonstration was conducted to vitrify municipal solid waste (MSW) combustor air pollution control residue (APC) under the USEPA Municipal Waste Innovative Technology Evaluation Program. uplicate demonstration was conducted using a process developed by Corning Inc. in a cold cr...

197

76 FR 12863 - National Emission Standards for Hazardous Air Pollutants for Reciprocating Internal Combustion...  

Federal Register 2010, 2011, 2012, 2013

...and required quality assurance or control activities, you must monitor continuously...and required quality assurance or control activities in data averages and...use a throttle to regulate intake air flow to control power during normal...

2011-03-09

198

Biomass combustion and indoor air pollution: the bright and dark sides of small is beautiful  

NASA Astrophysics Data System (ADS)

About half the world's households cook and/or heat daily with biomass fuels. At small scale, biomass combustion releases significant amounts of particulates, carbon monoxide, and hydrocarbons, the latter with significant concentrations of polycyclic aromatic hydrocarbons. Preliminary measurements in kitchens of developing-country villages have established airborne concentrations of these healthdamaging pollutants that are orders of magnitude above urban levels or relevant standards. Particle size measurements and dose calculations lead to significant concerns about potential health hazards. The few epidemiological studies are consistent with such effects although more work is clearly needed. These findings may have significant implications for the planning of rural energy development in a number of countries. In particular, they may relate directly to the question of the optimum balance between centralized and decentralized systems.

Smith, Kirk R.

1986-01-01

199

Combustion rate limits of hydrogen plus hydrocarbon fuel: Air diffusion flames from an opposed jet burner technique  

NASA Technical Reports Server (NTRS)

Combustion of H2/hydrocarbon (HC) fuel mixtures may be considered in certain volume-limited supersonic airbreathing propulsion applications. Effects of HC addition to H2 were evaluated, using a recent argon-bathed, coaxial, tubular opposed jet burner (OJB) technique to measure the extinction limits of counterflow diffusion flames. The OJB flames were formed by a laminar jet of (N2 and/or HC)-diluted H2 mixture opposed by a similar jet of air at ambient conditions. The OJB data, derived from respective binary mixtures of H2 and methane, ethylene, or propane HCs, were used to characterize BLOWOFF and RESTORE. BLOWOFF is a sudden breaking of the dish-shaped OJB flame to a stable torus or ring shape, and RESTORE marks sudden restoration of the central flame by radial inward flame propagation. BLOWOFF is a measure of kinetically-limited flame reactivity/speed under highly stretched, but relatively ideal impingement flow conditions. RESTORE measures inward radial flame propagation rate, which is sensitive to ignition processes in the cool central core. It is concluded that relatively small molar amounts of added HC greatly reduce the reactivity characteristics of counterflow hydrogen-air diffusion flames, for ambient initial conditions.

Pellett, Gerald L.; Guerra, Rosemary; Wilson, Lloyd G.; Reeves, Ronald N.; Northam, G. Burton

1987-01-01

200

Indoor air exposure to coal and wood combustion emissions associated with a high lung cancer rate in Xuan Wei, China  

SciTech Connect

Residents of Xuan Wei County in China have unusually high lung cancer mortality that cannot be attributed to tobacco use or occupational exposure. They are exposed to smoke from unvented, open pit coal or wood fires (often used for cooking and heating). The variation in lung cancer rates among communes within the county suggests that indoor combustion of smoky coal may be the prime determinant of lung cancer. To characterize the air in Xuan Wei homes, samples of air particles and semivolatile organic compounds were collected from homes located in two communes; one commune has a high rate of lung cancer, and the other has a low rate. Samples collected in the commune where the lung cancer rate is high and where smoky coal is the predominant fuel contained high concentrations of small particles with high organic content; organic extracts of these samples were mutagenic. Samples from homes in the wood-burning commune, which has a low rate of lung cancer, consisted mostly of larger particles of lower organic content and mutagenicity. The smoky coal sample was a mouse skin carcinogen and was a more potent initiator of skin tumors in comparison to the wood or smokeless coal sample.

Mumford, J.L.; Chapman, R.S.; Harris, D.B. (Environmental Protection Agency, Research Triangle Park, NC (USA)); He, X.Z.; Cao, S.R.; Xian, Y.L.; Li, X.M. (Institute of Environmental Health and Engineering, Beijing (China))

1989-01-01

201

Indoor air exposure to coal and wood combustion emissions associated with a high lung cancer rate in Xuan Wei, China  

SciTech Connect

Residents of Xuan Wei County in China have unusually high lung cancer mortality that cannot be attributed to tobacco use or occupational exposure. They are exposed to smoke from unvented, open pit coal or wood fires (often used for cooking and heating). The variation in lung cancer rates among communes within the county suggests that indoor combustion of smoky coal may be the prime determinant of lung cancer. To characterize the air in Xuan Wei homes, samples of the air particles and semivolatile organic compounds were collected from homes located in two communes; one commune has a high rate of lung cancer, and the other has a low rate. Samples collected in the commune where the lung cancer rate is high and where smoky coal is the predominant fuel contained high concentrations of small particles with high organic content; organic extracts of these samples were mutagenic. Samples from homes in the wood-burning commune, which has a low rate of lung cancer, consisted mostly of larger particles of lower organic content and mutagenicity. The smoky coal sample was a mouse skin carcinogen and was a more potent initiator of skin tumors in comparison to the wood or smokeless coal sample.

Mumford, J.L.; Chapman, R.S.; Harris, D.B.; He, X.Z.; Cac, S.R.

1989-01-01

202

Coal characterisation for NO x prediction in air-staged combustion of pulverised coals  

Microsoft Academic Search

A series of world-traded coal samples has been tested using the Imperial College high temperature wire mesh apparatus (HTWM) in order to assess the relationship between high temperature (1600°C) char nitrogen content and NOx formation in Hemweg Power Station (in the Netherlands) using deep furnace air staging. A linear relationship between high temperature char nitrogen and NOx formation has been

C. K. Man; J. R. Gibbins; J. G. Witkamp; J. Zhang

2005-01-01

203

Theoretical performance analysis of a constant velocity MHD generator for combustion products of hydrocarbon and air  

Microsoft Academic Search

Calculations are performed along a constant velocity, dc, MHD generator utilizing stoichiometric products of hydrocarbon and air. The gas is assumed to be in thermal equilibrium and representable by a Boltzman distribution so that the degree of ionization can be determined by means of the Saha equation. Variations in pressure, temperature, gaseous electrical conductivity, density, entropy, enthalpy, number density, degree

Blecher

1961-01-01

204

Research Opportunities for Cancer Associated with Indoor Air Pollution from Solid-Fuel Combustion  

EPA Science Inventory

Background: Indoor air pollution (IAP) derived largely from the use of solid fuels for cooking and heating affects about 3 billion people worldwide, resulting in substantial adverse health outcomes, including cancer. Women and children from developing countries are the most expos...

205

INDOOR AIR SAMPLING AND MUTAGENICITY STUDIES RELATED TO EMISSIONS FROM UNVENTED COAL COMBUSTION  

EPA Science Inventory

The purpose of the study is to develop sampling strategies and bioassay methods for indoor air in homes. The work reported here was conducted to prepare for a joint U.S.-China field study in Xuan Wei County, Yunnan Province, southern China, where the residents traditionally burn ...

206

BOOK REVIEW: Turbulent Combustion  

Microsoft Academic Search

The book Turbulent Combustion by Norbert Peters is a concise monograph on single-phase gaseous low Mach number turbulent combustion. It is compiled from the author's review papers on this topic plus some additional material. Norbert Peters characterizes turbulent combustion both by the way fuel and air are mixed and by the ratio of turbulent and chemical time scales. This approach

Norbert Peters

2001-01-01

207

Combustion & Health  

E-print Network

FFCOMBUSTION & HEALTH Winifred J. Hamilton, PhD, SM Clear Air Through Energy Efficiency (CATEE) Galveston, TX October 9?11, 2012 FFCOMBUSTION & HEALTH FFCOMBUSTION: THE THREAT ? Biggest threat to world ecosystems (and to human health...) ? Combustion of fossil fuels for ? Electricity ? Industrial processes ? Vehicle propulsion ? Cooking and heat ? Other ? Munitions ? Fireworks ? Light ? Cigarettes, hookahs? FFCOMBUSTION & HEALTH FFCOMBUSTION: THE THREAT ? SCALE (think health...

Hamilton, W.

2012-01-01

208

Combustion Characteristics of Pulverized Coal and Air\\/Gas Premixed Flame in a Double Swirl Combustor  

Microsoft Academic Search

An experimental work was performed to investigate the co-firing of pulverized coal and premixed gas\\/air streams in a double swirl combustor. The results showed that the NOx emissions are affected by the relative rates of thermal NOx formation and destruction via the pyrolysis of the fuel-N species in high temperature fuel-rich zones. Various burner designs were tested in order to

M. M. Kamal

2008-01-01

209

Numerical simulation of turbulent propane–air combustion with nonhomogeneous reactants  

Microsoft Academic Search

High-resolution two-dimensional numerical simulations have been performed for premixed turbulent propane–air flames propagating into regions of nonhomogeneous reactant stoichiometry. Simulations include complex chemical kinetics, realistic molecular transport, and fully resolved hydrodynamics (no turbulence model). Aerothermochemical conditions (pressure, temperature, stoichiometry, and turbulence velocity scale) approach those in an automotive gasoline direct-injection (GDI) engine at a low-speed, part-load operating condition. Salient findings

D. C. Haworth; R. J. Blint; B. Cuenot; T. J. Poinsot

2000-01-01

210

Studies on the mixing of liquid jets and pre-atomized sprays in confined swirling air flows for lean direct injection combustion  

NASA Astrophysics Data System (ADS)

A lean direct injection (LDI) combustion concept was introduced recently to obtain both low NOsbx emissions and high performance for advanced aircraft gas turbine engines. It was reported that pollutant emissions, especially NOsbx, in a lean combustion mode depend significantly on the degree of mixing (mixedness) of supplied air and liquid fuel droplets. From a viewpoint of environmental protection, therefore, uniform mixing of fuel and air in a very short period of time, i.e., well-stirred mixing, is crucially important in the LDI combustion mode. In the present study, as the first stage toward understanding the combustion phenomena in a lean direct injection (LDI) mode, the hydrodynamic behavior of liquid jets and pre-atomized sprays in confined swirling air flows is investigated. Laser-based flow visualization and image analysis techniques are applied to analyze the instantaneous motion of the mixing process of the jets and pre-atomized sprays. Statistical analysis system (SAS) software is utilized to analyze the experimental data, and correlate experimental parameters. Statistical parameters, such as centrality, degree of spread, and total area ratio of particles, are defined in this study, and used to quantify the mixedness (degree of mixing) of liquid particles in confined geometry. Two empirical equations are obtained to predict jet intact lengths and spray angles, respectively, in confined swirling air flows. It is found that initial jet characteristics, such as intact length and spray angle, determine the mixing of the liquid particles resulting from the jet. It is verified that image analysis is feasible in quantitative determination of the mixedness of liquid particles. Even though substantial improvements in liquid fuel injector systems are required before they can be considered adequate for LDI combustion at high pressure and high temperature, the results and ideas obtained from the present study will help engineers find better mixing methods for LDI combustors.

Huh, Jun-Young

211

Combustion and NOx emission characteristics with respect to staged-air damper opening in a 600 MWe down-fired pulverized-coal furnace under deep-air-staging conditions.  

PubMed

Deep-air-staging combustion conditions, widely used in tangential-fired and wall-arranged furnaces to significantly reduce NOx emissions, are premature up to now in down-fired furnaces that are designed especially for industry firing low-volatile coals such as anthracite and lean coal. To uncover combustion and NOx emission characteristics under deep-air-staging conditions within a newly operated 600 MWe down-fired furnace and simultaneously understand the staged-air effect on the furnace performance, full-load industrial-size measurements taken of gas temperatures and species concentrations in the furnace, CO and NOx emissions in flue gas, and carbon in fly ash were performed at various staged-air damper openings of 10%, 20%, 30%, and 50%. Increasing the staged-air damper opening, gas temperatures along the flame travel (before the flame penetrating the staged-air zone) increased initially but then decreased, while those in the staged-air zone and the upper part of the hopper continuously decreased and increased, respectively. On opening the staged-air damper to further deepen the air-staging conditions, O2 content initially decreased but then increased in both two near-wall regions affected by secondary air and staged air, respectively, whereas CO content in both two regions initially increased but then decreased. In contrast to the conventional understanding about the effects of deep-air-staging conditions, here increasing the staged-air damper opening to deepen the air-staging conditions essentially decreased the exhaust gas temperature and carbon in fly ash and simultaneously increased both NOx emissions and boiler efficiency. In light of apparently low NOx emissions and high carbon in fly ash (i.e., 696-878 mg/m(3) at 6% O2 and 9.81-13.05%, respectively) developing in the down-fired furnace under the present deep-air-staging conditions, further adjustments such as enlarging the staged-air declination angle to prolong pulverized-coal residence times in the furnace should be considered to improve the deep-air-staging combustion configuration. PMID:24274316

Kuang, Min; Li, Zhengqi; Wang, Zhihua; Jing, Xinjing; Liu, Chunlong; Zhu, Qunyi; Ling, Zhongqian

2014-01-01

212

Characterization of flame front surfaces in turbulent premixed methane/air combustion  

SciTech Connect

A detailed experimental investigation of the application of fractal geometry concepts in determining the turbulent burning velocity in the wrinkled flame regime of turbulent premixed combustion was conducted. The fractal dimension and cutoff scales were determined for six different turbulent flames in the wrinkled flame regime, where the turbulence intensity, turbulent length scale, and equivalence ratio were varied. Unlike previous reports, it has proved possible to obtain the fractal dimension and inner and outer cutoffs from individual flame images. From this individual data, the pdf distributions of all three fractal parameters, along with the distribution of the predicted increase in surface area, may be determined. The analysis of over 300 flame images for each flame condition provided a sufficient sample size to accurately define the pdf distributions and their means. However, the predicted S{sub T}/S{sub L}, calculated using fractal parameters, was significantly below the measured values. For conical flames, a geometrical modification factor was employed to predict S{sub T}/S{sub L}, however, this did little to improve the predictions. There appeared to be no dependence of the predicted S{sub T}/S{sub L} on the approach flow turbulence. The cutoffs did not seem to vary significantly with any of the length scales in the approach flow turbulence, although the fractal dimension did appear to have a weak dependence on u{prime}/S{sub L} and Re{sub {lambda}}. The probable reasons that fractal geometry does not correctly predict S{sub T}/S{sub L} are that S{sub T}/S{sub L} = A{sub w}/A{sub 0} does not hold in wrinkled turbulent premixed flames, that the flame front surface cannot be described by a single scaling exponent, or that these are not wrinkled flames. S{sub T} = turbulent burning velocity, S{sub L} = laminar burning velocity, A{sub w} = wrinkled flame surface area, and A{sub 0} = flow cross section area.

Smallwood, G.J.; Guelder, Oe.L.; Snelling, D.R. [National Research Council Canada, Ottawa, Ontario (Canada)] [National Research Council Canada, Ottawa, Ontario (Canada); Deschamps, B.M. [Inst. Francais du Petrole, Rueil-Malmaison (France)] [Inst. Francais du Petrole, Rueil-Malmaison (France); Goekalp, I. [CNRS, Orleans (France)] [CNRS, Orleans (France)

1995-06-01

213

Flamelet modelling of propane--air chemistry in turbulent non-premixed combustion  

SciTech Connect

This short paper describes the application of the flamelet modelling approach to the prediction of the species concentration field in a turbulent propane-air flame. The structure of the laminar flamelet, the microscopic element in the model, is computed using a semi-global expression for fuel disappearance in conjunction with an established reaction scheme for the oxidation of CO and H/sub 2/. Detailed predictions for a turbulent jet-flame are compared with available experimental data. The significant measure of non-equilibrium which the flamelet introduces leads to substantial improvements in the prediction of CO, H/sub 2/, and C/sub 3/H/sub 8/ mass fractions in comparison with the simplest alternative model, that of full chemical equilibrium.

Askari-Sardhai, A.; Liew, S.K.; Moss, J.B.

1985-01-01

214

Atomization and combustion characteristics of antimisting fuels using JT8D and air-boost injectors  

NASA Technical Reports Server (NTRS)

The atomization levels of antimisting fuels are presently determined for a JT8D fuel injector, a low emission airblast JT8D injector, and an air-boost injector, at operating conditions simulating engine operating conditions. The effects of the use of antimisting kerosene (AMK) on component performance are also studied in the case of an in-service JT8D engine. The use of the AMK fuel causes a decline in the quality of the spray, most notably as a large increase in the Sauter mean diameter for all three injector types. In addition, the idle patternation data obtained indicate that the low emission injector fuel distribution changed from a hollow cone Jet A spray having no fuel at its center to a semihollow spray cone in the case of AMK; this change could disrupt the combustor primary zone recirculation pattern.

Kennedy, J. B.; Florentino, A. J.

1986-01-01

215

Advection fog formation and aerosols produced by combustion-originated air pollution  

NASA Technical Reports Server (NTRS)

The way in which pollutants produced by the photochemical reaction of NO(X) and SO(X) affect the quality of the human environment through such phenomena as the formation of advection fog is considered. These pollutants provide the major source of condensation nuclei for the formation of fog in highways, airports and seaports. Results based on the monodisperse, multicomponent aerosol model show that: (1) condensation nuclei can grow and form a dense fog without the air having attained supersaturation; (2) the mass concentration range for NO(X) is one-third that of SO(X); and (3) the greater the mass concentration, the particle concentration, and the radius of condensation nuclei, the denser the fog that is formed.

Hung, R. J.; Liaw, G. S.; Vaughan, O. H., Jr.

1980-01-01

216

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

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. PMID:23162229

Topaz, Moris

2012-05-01

217

The effect of low-NO{sub x} combustion on residual carbon in fly ash and its adsorption capacity for air entrainment admixtures in concrete  

SciTech Connect

Fly ash from pulverized coal combustion contains residual carbon that can adsorb the air-entraining admixtures (AEAs) added to control the air entrainment in concrete. This is a problem that has increased by the implementation of low-NO{sub x} combustion technologies. In this work, pulverized fuel has been combusted in an entrained flow reactor to test the impact of changes in operating conditions and fuel type on the AEA adsorption of ash and NO{sub x} formation. Increased oxidizing conditions, obtained by improved fuel-air mixing or higher excess air, decreased the AEA requirements of the produced ash by up to a factor of 25. This was due to a lower carbon content in the ash and a lower specific AEA adsorptivity of the carbon. The latter was suggested to be caused by changes in the adsorption properties of the unburned char and a decreased formation of soot, which was found to have a large AEA adsorption capacity based on measurements on a carbon black. The NO{sub x} formation increased by up to three times with more oxidizing conditions and thus, there was a trade-off between the AEA requirements of the ash and NO{sub x} formation. The type of fuel had high impact on the AEA adsorption behavior of the ash. Ashes produced from a Columbian and a Polish coal showed similar AEA requirements, but the specific AEA adsorptivity of the carbon in the Columbian coal ash was up to six times higher. The AEA requirements of a South African coal ash was unaffected by the applied operating conditions and showed up to 12 times higher AEA adsorption compared to the two other coal ashes. This may be caused by larger particles formed by agglomeration of the primary coal particles in the feeding phase or during the combustion process, which gave rise to increased formation of soot. (author)

Pedersen, K.H.; Jensen, A.D.; Dam-Johansen, K. [Department of Chemical and Biochemical Engineering, Technical University of Denmark, Building 229, DK-2800 Kgs. Lyngby (Denmark)

2010-02-15

218

Thermochemical nonequilibrium and radiative interactions in supersonic hydrogen-air combustion  

NASA Technical Reports Server (NTRS)

The two-dimensional, elliptic Navier-Stokes equations are used to investigate supersonic flows with nonequilibrium chemistry and thermodynamics, coupled with radiation, for hydrogen-air systems. The chemistry source term in the species equation is treated implicitly to alleviate the stiffness associated with fast reactions. The explicit, unsplit MacCormack finite-difference scheme is used to advance the governing equations in time, until convergence is achieved. The specific problem considered is the premixed, expanding flow in a supersonic nozzle. The reacting flow consists of seven species, one of which is the inert N2 molecule. The thermal state of the gas is modeled with one translational-rotational temperature and five vibrational temperatures. The harmonic oscillator model is used in the formulation for vibrational relaxation. The tangent slab approximation is used in the radiative flux formulation. A pseudo-gray model is used to represent the absorption-emission characteristics of the participating species. Results obtained for specific conditions indicate the presence of nonequilibrium in the expansion region. This reduces the radiative interactions and can have a significant influence on the flowfield.

Chandrasekhar, R.; Tiwari, S. N.

1992-01-01

219

Characterization of air emissions from the simulated open combustion of fiberglass materials. Final report, January 1992-August 1993  

SciTech Connect

The exposure of persons to fiberglass combustion emissions from structural fires, fires at waste landfills, and fires at demolition sites has become an issue of increasing concern. The study identifies and quantifies a broad range of pollutants that are discharged during small-scale, simulated, open combustion of fiberglass and reports these emissions relative to the mass of fiberglass material combusted. Two types of fiberglass materials (representing the boating and building materials industries) were combusted in a controlled outbuilding designed to simulate open burning. Volatile, semivolatile, and particulate-bound organics were collected and analyzed by gas chromatography/mass spectrometry (GC/MS).

Lutes, C.C.; Ryan, J.V.

1993-12-01

220

Gu, X., Haq, M. Z., Lawes, M. and Woolley, R. (2000), "Laminar Burning Velocity and Markstein Lengths of Methane-Air Mixtures", Combustion and Flame, 121:41-58  

E-print Network

Metghalchi, M. and Keck, J. C. (1982), "Burning Velocities of Air with Methanol, Isooctane and Indolene by retaining a fraction of the combustion products from a previous experiment. Figure 1 Bomb schematic

221

Experiment investigations on the performance of a centrally fuel rich swirl coal combustion burner: Influence of primary air ratio - article no. A39  

SciTech Connect

A three-component particle-dynamics anemometer is used to measure, in the near-burner region, the influence of the primary air ratio on the gas/particle two phase characteristics for a centrally fuel rich swirl coal combustion burner, on a gas/particle two phase test facility. Velocities, particle volume flux profiles and particle relative number concentrations were obtained. With a low primary air ratio, the axial velocities for gas and particles on the chamber axis are always small and easily reach the negative, and the central recirculation zone is easily formed and much closer to the outlet of the burner. In each cross-section, in the radius range from Rair ratio is higher than that with a low primary air ratio. The influence of gas/particle flow characteristics with a different primary air ratio on combustion has been analyzed.

Chen, Z.C.; Li, Z.Q.; Jing, J.P.; Wei, H.D.; Chen, L.Z.; Wu, S.H.; Yao, Y. [Harbin Institute of Technology, Harbin (China)

2008-07-01

222

Air pollution from household solid fuel combustion in India: an overview of exposure and health related information to inform health research priorities  

PubMed Central

Environmental and occupational risk factors contribute to nearly 40% of the national burden of disease in India, with air pollution in the indoor and outdoor environment ranking amongst leading risk factors. It is now recognized that the health burden from air pollution exposures that primarily occur in the rural indoors, from pollutants released during the incomplete combustion of solid fuels in households, may rival or even exceed the burden attributable to urban outdoor exposures. Few environmental epidemiological efforts have been devoted to this setting, however. We provide an overview of important available information on exposures and health effects related to household solid fuel use in India, with a view to inform health research priorities for household air pollution and facilitate being able to address air pollution within an integrated rural–urban framework in the future. PMID:21987631

Balakrishnan, Kalpana; Ramaswamy, Padmavathi; Sambandam, Sankar; Thangavel, Gurusamy; Ghosh, Santu; Johnson, Priscilla; Mukhopadhyay, Krishnendu; Venugopal, Vidhya; Thanasekaraan, Vijayalakshmi

2011-01-01

223

MUNICIPAL WASTEWATER SLUDGE COMBUSTION TECHNOLOGY  

EPA Science Inventory

The publication describes and evaluates the various municipal sludge combustion systems. It also emphasizes the necessity for considering and evaluating the costs involved in the total sludge management train, including dewatering, combustion, air pollution control, and ash dispo...

224

Twenty-Seventh Symposium (International) on Combustion/The Combustion Institute, 1998/pp. 10571064 UNSTEADY FLAMELET MODELING OF TURBULENT HYDROGEN-AIR  

E-print Network

and the mixture fraction field. Transient effects occurring in steady jet diffusion flames are discussed in terms­1064 UNSTEADY FLAMELET MODELING OF TURBULENT HYDROGEN-AIR DIFFUSION FLAMES H. PITSCH, M. CHEN and N. PETERS-air diffusion flame. An unsteady flamelet is solved interactively with a CFD solver for the tur- bulent flow

Pitsch, Heinz

225

Overfeed fixed-bed combustion of wood  

Microsoft Academic Search

Research on the combustion of wood on a fixed grate with a separate supply of combustion air is described in this paper. From the layer of the wood on the grate, only fixed carbon was burned in the primary combustion chamber in the presence of primary air, whereas the volatiles were burned subsequently in the secondary combustion chamber in the

Janez Oman; Matija Tuma

1999-01-01

226

Air  

MedlinePLUS

... do to protect yourself from dirty air . Indoor air pollution and outdoor air pollution Air can be polluted indoors and it can ... this chart to see what things cause indoor air pollution and what things cause outdoor air pollution! Indoor ...

227

Combustion Air Control  

E-print Network

The results of boiler control improvement projects may be disappointing due to unrealistic expectations and a failure to recognize the study and analysis required to ensure success. Early recognition of the need for data collection and boiler...

Hughart, C. L.

1979-01-01

228

Hazardous air pollutants from the combustion of an emulsified heavy fuel oil in a firetube boiler. Final report, May-November 1995  

SciTech Connect

The report gives results of measuring emissions of hazardous air pollutants (HAPS) from the combustion flue gases of a No. 6 fuel oil, both with and without an emulsifying agent, in a 2.5 million Btu/hr (732 kW) firetube boiler with the purpose determining the impacts of the emulsifier on HAP emissions. The boiler flue gases were sampled and analyzed for both metal and organic HAPs, and the effects of the emulsification on criteria emissions such as carbon dioxide (CO), nitrogen oxides (NOx), and particulate matter (PM) were also measured.

Miller, C.A.

1996-02-01

229

Regulating Low-NOx and High-Burnout Deep-Air-Staging Combustion under Real-Furnace Conditions in a 600 MWe Down-Fired Supercritical Boiler by Strengthening the Staged-Air Effect.  

PubMed

A 600 MWe down-fired pulverized-coal supercritical boiler, which was equipped with a deep-air-staging combustion system for reducing the particularly high NOx emissions, suffered from the well-accepted contradiction between low NOx emissions and high carbon in fly ash, in addition to excessively high gas temperatures in the hopper that jeopardized the boiler's safe operations. Previous results uncovered that under low-NOx conditions, strengthening the staged-air effect by decreasing the staged-air angle and simultaneously increasing the staged-air damper opening alleviated the aforementioned problems to some extent. To establish low-NOx and high-burnout circumstances and control the aforementioned hopper temperatures, a further staged-air retrofit with horizontally redirecting staged air through an enlarged staged-air slot area was performed to greatly strengthen the staged-air effect. Full-load industrial-size measurements were performed to confirm the availability of this retrofit. The present data were compared with those published results before the retrofit. High NOx emissions, low carbon in fly ah, and high hopper temperatures (i.e., levels of 1036 mg/m(3) at 6% O2, 3.72%, and about 1300 °C, respectively) appeared under the original conditions with the staged-air angle of 45° and without overfire air (OFA) application. Applying OFA and reducing the angle to 20° achieved an apparent NOx reduction and a moderate hopper temperature decrease while a sharp increase in carbon in fly ash (i.e., levels of 878 mg/m(3) at 6% O2, about 1200 °C, and 9.81%, respectively). Fortunately, the present staged-air retrofit was confirmed to be applicable in regulating low-NOx, high-burnout, and low hopper temperature circumstances (i.e., levels of 867 mg/m(3) at 6% O2, 5.40%, and about 1100 °C, respectively). PMID:25256210

Kuang, Min; Wang, Zhihua; Zhu, Yanqun; Ling, Zhongqian; Li, Zhengqi

2014-10-21

230

Fluidized coal combustion  

NASA Technical Reports Server (NTRS)

Fluidized-bed coal combustion process, in which pulverized coal and limestone are burned in presence of forced air, may lead to efficient, reliable boilers with low sulfur dioxide and nitrogen dioxide emissions.

Moynihan, P. I.; Young, D. L.

1979-01-01

231

A Novel High-Heat Transfer Low-NO{sub x} Natural Gas Combustion System. Final Technical Report  

SciTech Connect

A novel high-heat transfer low NO(sub x) natural gas combustion system. The objectives of this program are to research, develop, test, and commercialize a novel high-heat transfer low-NO{sub x} natural gas combustion system for oxygen-, oxygen-enriched air, and air-fired furnaces. This technology will improve the process efficiency (productivity and product quality) and the energy efficiency of high-temperature industrial furnaces by at least 20%. GTI's high-heat transfer burner has applications in high-temperature air, oxygen-enriched air, and oxygen furnaces used in the glass, metals, cement, and other industries. Development work in this program is focused on using this burner to improve the energy efficiency and productivity of glass melting furnaces that are major industrial energy consumers. The following specific project objectives are defined to provide a means of achieving the overall project objectives. (1) Identify topics to be covered, problems requiring attention, equipment to be used in the program, and test plans to be followed in Phase II and Phase III. (2) Use existing codes to develop models of gas combustion and soot nucleation and growth as well as a thermodynamic and parametric description of furnace heat transfer issues. (3) Conduct a parametric study to confirm the increase in process and energy efficiency. (4) Design and fabricate a high-heat transfer low-NOx natural gas burners for laboratory, pilot- and demonstration-scale tests. (5) Test the high-heat transfer burner in one of GTI's laboratory-scale high-temperature furnaces. (6) Design and demonstrate the high-heat transfer burner on GTI's unique pilot-scale glass tank simulator. (7) Complete one long term demonstration test of this burner technology on an Owens Corning full-scale industrial glass melting furnace. (8) Prepare an Industrial Adoption Plan. This Plan will be updated in each program Phase as additional information becomes available. The Plan will include technical and economic analyses, energy savings and waste reduction predictions, evaluation of environmental effects, and outline issues concerning manufacturing, marketing, and financing. Combustion Tec, Owens Corning, and GTI will all take active roles in defining this Plan. During Phase I, the first three objectives were addressed and completed along with the design component of the fourth objective. In Phase II, the fabrication component of the fourth objective was completed along with objectives five and six. Results of the Phase I work were reported in the Phase I Final Report and are summarized in this Final Technical Report. Work for Phase II was divided in four specific Tasks. Results of the Phase II work were reported in the Phase II Final Report and are also summarized in this Final Technical Report. No Phase III Final Report was prepared, so this Final Technical Report presents the results of Phase III commercial demonstration efforts. A description of each Task in Phases I, II, and III is presented in this report.

Abbasi, H.

2004-01-01

232

Experimental and numerical study of the accuracy of flame-speed measurements for methane/air combustion in a slot burner  

SciTech Connect

Measuring the velocities of premixed laminar flames with precision remains a controversial issue in the combustion community. This paper studies the accuracy of such measurements in two-dimensional slot burners and shows that while methane/air flame speeds can be measured with reasonable accuracy, the method may lack precision for other mixtures such as hydrogen/air. Curvature at the flame tip, strain on the flame sides and local quenching at the flame base can modify local flame speeds and require corrections which are studied using two-dimensional DNS. Numerical simulations also provide stretch, displacement and consumption flame speeds along the flame front. For methane/air flames, DNS show that the local stretch remains small so that the local consumption speed is very close to the unstretched premixed flame speed. The only correction needed to correctly predict flame speeds in this case is due to the finite aspect ratio of the slot used to inject the premixed gases which induces a flow acceleration in the measurement region (this correction can be evaluated from velocity measurement in the slot section or from an analytical solution). The method is applied to methane/air flames with and without water addition and results are compared to experimental data found in the literature. The paper then discusses the limitations of the slot-burner method to measure flame speeds for other mixtures and shows that it is not well adapted to mixtures with a Lewis number far from unity, such as hydrogen/air flames. (author)

Selle, L.; Ferret, B. [Universite de Toulouse, INPT, UPS, IMFT, Institut de Mecanique des Fluides de Toulouse (France); CNRS, IMFT, Toulouse (France); Poinsot, T. [Universite de Toulouse, INPT, UPS, IMFT, Institut de Mecanique des Fluides de Toulouse (France); CNRS, IMFT, Toulouse (France); CERFACS, Toulouse (France)

2011-01-15

233

Combuster. [low nitrogen oxide formation  

NASA Technical Reports Server (NTRS)

A combuster is provided for utilizing a combustible mixture containing fuel and air, to heat a load fluid such as water or air, in a manner that minimizes the formation of nitrogen oxide. The combustible mixture passes through a small diameter tube where the mixture is heated to its combustion temperature, while the load fluid flows past the outside of the tube to receive heat. The tube is of a diameter small enough that the combustible mixture cannot form a flame, and yet is not subject to wall quench, so that combustion occurs, but at a temperature less than under free flame conditions. Most of the heat required for heating the combustible mixture to its combustion temperature, is obtained from heat flow through the walls of the pipe to the mixture.

Mckay, R. A. (inventor)

1978-01-01

234

Combustion characteristics and flame stability at the microscale: a CFD study of premixed methane\\/air mixtures  

Microsoft Academic Search

A two-dimensional elliptic, computational fluid dynamics (CFD) model of a microburner is solved to study the effects of microburner dimensions, conductivity and thickness of wall materials, external heat losses, and operating conditions on combustion characteristics and flame stability. We have found that the wall conductivity and thickness are very important as they determine the upstream heat transfer, which is necessary

D. G. Norton; D. G. Vlachos

2003-01-01

235

Combustion of Micropowdered Biomass  

NASA Astrophysics Data System (ADS)

Combustion of finely powdered biomass has the potential to replace heating oil, which accounts for a significant fraction of US oil consumption, in heating, cooling and local power generation applications. When ground to 30-150 micron powders and dispersed in air, wood and other biomass can undergo deflagrating combustion, as occurs with gaseous and dispersed liquid fuels. Combustion is very nearly complete, and in contrast to sugar/starch or cellulose-derived ethanol, nearly all of the available plant mass is converted to usable energy so the economics are much more promising. We are exploring the fundamental combustion science of biomass powders in this size range. In particular, we are examining how powder size, powder composition (including the fraction of volatile organics) and other parameters affect the combustion regime and the combustion products.

Geil, Ethan; Thorne, Robert

2009-03-01

236

Carbon black enriched combustion  

SciTech Connect

A process for combustion of carbon black enriched gaseous hydrocarbon fuels is described comprising: entraining a plurality of carbon black particles in a carrier fluid, forming a carbon black/carrier fluid mixture; injecting said carbon black/carrier fluid mixture through a center nozzle of a fluid injector into a combustion chamber, said fluid injector having an outer nozzle concentrically disposed around said center nozzle forming an annular chamber between said center nozzle and said outer nozzle; injecting at least a first portion of a gaseous hydrocarbon fuel through said annular chamber into said combustion chamber forming a carbon black enriched gaseous hydrocarbon fuel; mixing said carbon black enriched gaseous hydrocarbon fuel with combustion air, forming a fuel/air mixture; and igniting said fuel/air mixture.

Joshi, M.L.; Tester, M.E.

1993-06-29

237

Quantifying the effects of exposure to indoor air pollution from biomass combustion on acute respiratory infections in developing countries.  

PubMed Central

Acute respiratory infections (ARI) are the leading cause of burden of disease worldwide and have been causally linked with exposure to pollutants from domestic biomass fuels in developing countries. We used longitudinal health data coupled with detailed monitoring and estimation of personal exposure from more than 2 years of field measurements in rural Kenya to estimate the exposure-response relationship for particulates < 10 microm diameter (PM(10)) generated from biomass combustion. Acute respiratory infections and acute lower respiratory infections are concave, increasing functions of average daily exposure to PM(10), with the rate of increase declining for exposures above approximately 1,000-2,000 microg/m(3). This first estimation of the exposure-response relationship for the high-exposure levels characteristic of developing countries has immediate and important consequences for international public health policies, energy and combustion research, and technology transfer efforts that affect more than 2 billion people worldwide. PMID:11401759

Ezzati, M; Kammen, D M

2001-01-01

238

Effect of heat recirculation on the self-sustained catalytic combustion of propane/air mixtures in a quartz reactor  

SciTech Connect

The self-sustained catalytic combustion of propane is experimentally studied in a two-pass, quartz heat-recirculation reactor (HRR) and compared to that in a no (heat) recirculation reactor (NRR). Structured monolithic reactors with Pt/{gamma}-Al{sub 2}O{sub 3}, LaMnO{sub 3}/{gamma}-Al{sub 2}O{sub 3}, and Pt doped perovskite catalysts have been compared in the HRR and NRR configurations. Heat recirculation enhances combustion stability, by widening the operating window of self-sustained operation, and changes the mode of stability loss from blowout to extinction. It is found that thermal shields (upstream and downstream of the monolith) play no role in the stability of a HRR but increase the stability of a NRR. The stability of a HRR follows this trend: Pt/{gamma}-Al{sub 2}O{sub 3} > doped perovskite > LaMnO{sub 3}/{gamma}-Al{sub 2}O{sub 3}. Finally, a higher cell density monolith enlarges the operating window of self-sustained combustion, and allows further increase of the power density of the process. (author)

Scarpa, A. [Dipartimento di Ingegneria Chimica, Universita degli Studi di Napoli ''Federico II'', P.le V. Tecchio 80, 80125 Naples (Italy); Department of Chemical Engineering, Center for Catalytic Science and Technology (CCST), and Center for Composite Materials (CCM), University of Delaware, 150 Academy Street, Newark, DE 19716 (United States); Pirone, R. [Istituto di Ricerche sulla Combustione-CNR, P.le V. Tecchio 80, 80125 Naples (Italy); Russo, G. [Dipartimento di Ingegneria Chimica, Universita degli Studi di Napoli ''Federico II'', P.le V. Tecchio 80, 80125 Naples (Italy); Vlachos, D.G. [Department of Chemical Engineering, Center for Catalytic Science and Technology (CCST), and Center for Composite Materials (CCM), University of Delaware, 150 Academy Street, Newark, DE 19716 (United States)

2009-05-15

239

EFFECTS OF CHANGING COALS ON THE EMISSIONS OF METAL HAZARDOUS AIR POLLUTANTS FROM THE COMBUSTION OF PULVERIZED COAL  

EPA Science Inventory

The report discusses tests conducted at EPA's Air Pollution Prevention and Control Division to evaluate the effects of changing coals on emissions of metal hazardous air pollutants from coal-fired boilers. Six coals were burned in a 29 kW (100,000 Btu/hr) down-fired combustor und...

240

Species and velocity visualization of unseeded heated air and combusting hydrogen jets using laser and flashlamp sources  

NASA Technical Reports Server (NTRS)

Three techniques for the visualization of species and/or velocity in unseeded H2/air flames and heated air jets are described and preliminary image data are presented. The techniques described are: (1) simultaneous ArF laser imaging of H2, O2, and Rayleigh cross-section weighted density in an H2, O2, and Rayleigh cross-section weighted density in an H2/air flame; (2) ultraviolet flashlamp imaging of O2, OH, and Rayleigh cross-section weighted density in an H2/air flame; and (3) Raman Excitation plus Laser Induced Electronic Fluorescence velocimetry in heater air flows, up to static temperatures of 700 K. Application of these techniques, individually or in combination, should provide useful insight into mixing and reacting flows containing H2, O2, N2 and reaction intermediates such as OH.

Diskin, Glenn S.; Lempert, Walter R.; Miles, Richard B.

1990-01-01

241

Detonation cell size measurements in high-temperature hydrogen-air-steam mixtures at the BNL high-temperature combustion facility  

SciTech Connect

The High-Temperature Combustion Facility (HTCF) was designed and constructed with the objective of studying detonation phenomena in mixtures of hydrogen-air-steam at initially high temperatures. The central element of the HTCF is a 27-cm inner-diameter, 21.3-m long cylindrical test vessel capable of being heating to 700K {+-} 14K. A unique feature of the HTCF is the {open_quotes}diaphragmless{close_quotes} acetylene-oxygen gas driver which is used to initiate the detonation in the test gas. Cell size measurements have shown that for any hydrogen-air-steam mixture, increasing the initial mixture temperature, in the range of 300K to 650K, while maintaining the initial pressure of 0.1 MPa, decreases the cell size and thus makes the mixture more detonable. The effect of steam dilution on cell size was tested in stoichiometric and off-stoichiometric (e.g., equivalence ratio of 0.5) hydrogen-air mixtures. Increasing the steam dilution in hydrogen-air mixtures at 0.1 MPa initial pressure increases the cell size, irrespective of initial temperature. It is also observed that the desensitizing effect of steam diminished with increased initial temperature. A 1-dimensional, steady-state Zel`dovich, von Neumann, Doring (ZND) model, with full chemical kinetics, has been used to predict cell size for hydrogen-air-steam mixtures at different initial conditions. Qualitatively the model predicts the overall trends observed in the measured cell size versus mixture composition and initial temperature and pressure. It was found that the proportionality constant used to predict detonation cell size from the calculated ZND model reaction zone varies between 10 and 100 depending on the mixture composition and initial temperature. 32 refs., 35 figs.

Ciccarelli, G.; Ginsberg, T.; Boccio, J.L. [and others

1997-11-01

242

Formation mechanisms of combustion chamber deposits  

E-print Network

Combustion chamber deposits are found in virtually all internal combustion engines after a few hundred hours of operation. Deposits form on cylinder, piston, and head surfaces that are in contact with fuel-air mixture ...

O'Brien, Christopher J. (Christopher John)

2001-01-01

243

Efficient gas hot-air furnace and heating process  

Microsoft Academic Search

This patent describes space heating apparatus in which fuel gas is burned and heat is transferred from the resulting combustion gases to a cool air stream to produce heated air. It comprises a combustion chamber, the chamber comprising an inlet for receiving combustion air and a burner for burning fuel gas in the combustion air to produce combustion gases; and

Astle; W. B. Jr

1991-01-01

244

14 CFR 23.859 - Combustion heater fire protection.  

Code of Federal Regulations, 2013 CFR

...exceeds safe limits. (C) The combustion airflow becomes inadequate for safe...warn the crew when any heater whose heat output is essential for safe operation...crew. (f) Air intakes. Each combustion and ventilating air intake must...

2013-01-01

245

14 CFR 23.859 - Combustion heater fire protection.  

Code of Federal Regulations, 2012 CFR

...exceeds safe limits. (C) The combustion airflow becomes inadequate for safe...warn the crew when any heater whose heat output is essential for safe operation...crew. (f) Air intakes. Each combustion and ventilating air intake must...

2012-01-01

246

14 CFR 23.859 - Combustion heater fire protection.  

Code of Federal Regulations, 2011 CFR

...exceeds safe limits. (C) The combustion airflow becomes inadequate for safe...warn the crew when any heater whose heat output is essential for safe operation...crew. (f) Air intakes. Each combustion and ventilating air intake must...

2011-01-01

247

14 CFR 23.859 - Combustion heater fire protection.  

...exceeds safe limits. (C) The combustion airflow becomes inadequate for safe...warn the crew when any heater whose heat output is essential for safe operation...crew. (f) Air intakes. Each combustion and ventilating air intake must...

2014-01-01

248

14 CFR 23.859 - Combustion heater fire protection.  

Code of Federal Regulations, 2010 CFR

...exceeds safe limits. (C) The combustion airflow becomes inadequate for safe...warn the crew when any heater whose heat output is essential for safe operation...crew. (f) Air intakes. Each combustion and ventilating air intake must...

2010-01-01

249

Environmental control implications of generating electric power from coal. 1977 technology status report. Appendix D. Assessment of NO/sub x/ control technology for coal fired utility boilers. [Low-excess-air, staged combustion, flu gas recirculation and burner design  

SciTech Connect

An NOx control technology assessment study was conducted to examine the effectiveness of low-excess-air firing, staged combustion, flue gas recirculation, and current burner/boiler designs as applied to coal-fired utility boilers. Significant variations in NOx emissions exist with boiler type, firing method, and coal type, but a relative comparison of emissions control performance, cost, and operational considerations is presented for each method. The study emphasized the numerous operational factors that are of major importance to the user in selecting and implementing a combustion modification technique. Staged combustion and low-excess-air operation were identified as the most cost-effective methods for existing units. Close control of local air/fuel ratios and rigorous combustion equipment maintenance are essential to the success of both methods. Flue gas recirculation is relatively ineffective and has the added concern of tube erosion. More research is needed to resolve potential corrosion concerns with low-NOx operating modes. Low-NOx burners in conjunction with a compartmentalized windbox are capable of meeting a 0.6-lb/million Btu emission level on new units. Advanced burner designs are being developed to meet research emission goals of approximately 0.25 lb/MBtu.

Not Available

1977-12-01

250

Simplified Two-Time Step Method for Calculating Combustion Rates and Nitrogen Oxide Emissions for Hydrogen/Air and Hydorgen/Oxygen  

NASA Technical Reports Server (NTRS)

A simplified single rate expression for hydrogen combustion and nitrogen oxide production was developed. Detailed kinetics are predicted for the chemical kinetic times using the complete chemical mechanism over the entire operating space. These times are then correlated to the reactor conditions using an exponential fit. Simple first order reaction expressions are then used to find the conversion in the reactor. The method uses a two-time step kinetic scheme. The first time averaged step is used at the initial times with smaller water concentrations. This gives the average chemical kinetic time as a function of initial overall fuel air ratio, temperature, and pressure. The second instantaneous step is used at higher water concentrations (> 1 x 10(exp -20) moles/cc) in the mixture which gives the chemical kinetic time as a function of the instantaneous fuel and water mole concentrations, pressure and temperature (T4). The simple correlations are then compared to the turbulent mixing times to determine the limiting properties of the reaction. The NASA Glenn GLSENS kinetics code calculates the reaction rates and rate constants for each species in a kinetic scheme for finite kinetic rates. These reaction rates are used to calculate the necessary chemical kinetic times. This time is regressed over the complete initial conditions using the Excel regression routine. Chemical kinetic time equations for H2 and NOx are obtained for H2/air fuel and for the H2/O2. A similar correlation is also developed using data from NASA s Chemical Equilibrium Applications (CEA) code to determine the equilibrium temperature (T4) as a function of overall fuel/air ratio, pressure and initial temperature (T3). High values of the regression coefficient R2 are obtained.

Molnar, Melissa; Marek, C. John

2005-01-01

251

CO{sub 2} emission abatement in IGCC power plants by semiclosed cycles: Part B -- With air-blown combustion and CO{sub 2} physical absorption  

SciTech Connect

This paper analyzes the fundamentals of IGCC power plants with carbon dioxide removal systems, by a cycle configuration alternative to the one discussed in Part A (with oxygen-blown combustion). The idea behind this proposal is to overcome the major drawbacks of the previous solution (large oxygen consumption and re-design of the gas turbine unit), by means of a semiclosed cycle using air as the oxidizer. Consequently, combustion gases are largely diluted by nitrogen and cannot be simply compressed to produce liquefied CO{sub 2} for storage or disposal. However, CO{sub 2} concentration remains high enough to make separation possible by a physical absorption process. It requires a re-pressurization of the flow subtracted from the cycle, with relevant consequences on the plant energy balance. The configuration and the thermodynamic performance of this plant concept are extensively addressed in the paper. As in the first part, the influence of the pressure ratio is discussed, but values similar to the ones adopted in commercial heavy-duty machines provide here acceptable performance. Proper attention was paid to the impact of the absorption process on the energy consumption. The resulting net overall efficiency is again in the 38--39% range, with assumptions fully comparable to the ones of Part A. Finally, the authors demonstrate that the present scheme enables the use of unmodified machines, but large additional equipment is required for exhausts treatment and CO{sub 2} separation. A final comparison between the two semiclosed cycle concepts is therefore addressed.

Chiesa, P.; Lozza, G.

1999-10-01

252

Seasonal mercury concentrations measured in rural air in Southern Poland. Contribution from local and regional coal combustion  

NASA Astrophysics Data System (ADS)

The concentration of total atmospheric gaseous mercury (TGM) and total particulate mercury (TPM) have been measured during one summer campaign (19-29 August 2003) and one winter campaign (26 January-3 February 2004) at a rural site in Poland. Mercury deposition was also measured using bulk samplers. The measurement campaigns were performed in a typical agricultural area of Southern Poland where 85% of the houses use low capacity domestic heating units (DHUs) fuelled with hard coal during the cold season. An average TGM value of 1.63±0.35ngm was obtained in the summer campaign, whereas a 2.5 times higher TGM concentration was found during winter. The mean TPM concentration during summer was 0.11±0.05ngm while 10 times higher values were obtained during the winter campaign. The mercury deposition was also found to be much higher during winter in comparison to summer. The summer TGM values are at the same level as the annual average TGM at background locations in most West European countries including Scandinavia. The higher TGM values in winter are most likely due to the use of DHUs in the local area. However, both summer and winter TPM concentrations and mercury deposition fluxes are much higher than in most neighbouring West European countries. This probably reflects the regional use of coal combustion for electric energy production and in low-capacity DHUs.

Zielonka, Urszula; Hlawiczka, Stanislaw; Fudala, Janina; Wängberg, Ingvar; Munthe, John

253

Study of a blast-furnace smelting technology which involves the injection of pulverized-coal fuel, natural gas, and an oxygen-enriched blast into the hearth  

SciTech Connect

Studies were made of features of a blast-furnace smelting technology that involves the injection of natural gas (NG), oxygen (O{sub 2}) and pulverized-coal fuel (PCF) into the hearth. The technology has been implemented in the compensation and overcompensation regimes, which has made it possible to maintain or improve the gas dynamics of the furnace, the conditions for the reduction of iron oxides, the heating of the charge, and PCF combustion in the tuyere zone as PCF consumption is increased and coke use is decreased. Under the given conditions, with the blast having an oxygen content of 25.64-25.7%, the hearth injection of 131-138 kg PCF and 65-69 m{sup 3} NG for each ton of pig iron has made it possible to reduce coke consumption by 171-185 kg/ton pig (30.2-32.7%), reduce the consumption of comparison fuel by 36-37 kg/ton (5.2-5.3%), and lower the production cost of the pig iron by 43-49 hryvnas/ton (3.7-6.4%). Here, furnace productivity has increased 3.8-6.5%, while the quality of the conversion pig iron remains the same as before. Measures are being implemented to further increase the level and efficiency of PCF use.

Ryzhenkov, A.N.; Yaroshevskii, S.L.; Zamuruev, V.P.; Popov, V.E.; Afanas'eva, Z.K.

2006-05-15

254

Modelling inhalation exposure to combustion-related air pollutants in residential buildings: Application to health impact assessment.  

PubMed

Buildings in developed countries are becoming increasingly airtight as a response to stricter energy efficiency requirements. At the same time, changes are occurring to the ways in which household energy is supplied, distributed and used. These changes are having important impacts on exposure to indoor air pollutants in residential buildings and present new challenges for professionals interested in assessing the effects of housing on public health. In many circumstances, models are the most appropriate way with which to examine the potential outcomes of future environmental and/or building interventions and policies. As such, there is a need to consider the current state of indoor air pollution exposure modelling. Various indoor exposure modelling techniques are available, ranging from simple statistical regression and mass-balance approaches, to more complex multizone and computational fluid dynamics tools that have correspondingly large input data requirements. This review demonstrates that there remain challenges which limit the applicability of current models to health impact assessment. However, these issues also present opportunities for better integration of indoor exposure modelling and epidemiology in the future. The final part of the review describes the application of indoor exposure models to health impact assessments, given current knowledge and data, and makes recommendations aimed at improving model predictions in the future. PMID:20875687

Milner, James; Vardoulakis, Sotiris; Chalabi, Zaid; Wilkinson, Paul

2011-01-01

255

Seasonal, anthropogenic, air mass, and meteorological influences on the atmospheric concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs): Evidence for the importance of diffuse combustion sources  

SciTech Connect

Sampling programs were undertaken to establish air polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F) concentrations at a semirural site on the northwest coast of England in autumn and summer and to investigate factors causing their variability. Changing source inputs, meteorological parameters, air masses, and the impact of a festival when it is customary to light fireworks and bonfires were investigated. Various lines of evidence from the study point to diffuse, combustion-related sources being a major influence on ambient air concentrations. Higher PCDD/F concentrations were generally associated with air masses that had originated and moved over land, particularly during periods of low ambient temperature. Low concentrations were associated with air masses that had arrived from the Atlantic Ocean/Irish Sea to the west of the sampling site and had little or no contact with urban/industrialized areas. Concentrations in the autumn months were 2 to 10 times higher than those found in the summer.

Lee, R.G.M.; Green, N.J.L.; Lohmann, R.; Jones, K.C. [Lancaster Univ. (United Kingdom)] [Lancaster Univ. (United Kingdom)

1999-09-01

256

Combustion noise  

NASA Technical Reports Server (NTRS)

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.

Strahle, W. C.

1977-01-01

257

The 33rd JANNAF Combustion Subcommittee Meeting. Volume 2  

NASA Technical Reports Server (NTRS)

This volume, the second of four volumes, is a collection of 48 unclassified/unlimited papers which were presented at the 33rd Joint Army-Navy-NASA-Air Force (JANNAF) Combustion Subcommittee Meeting conjunction with the Propulsion Systems Hazards Subcommittee held 4-8 November 1996 at the Naval Postgraduate School, Monterey, CA. The JANNAF papers contained in this volume review many areas of solid propellant combustion to include combustion fundamentals, combustion instability fundamentals and combustion instability applied to motors, AP combustion, Nitramine combustion, metal combustion, kinetics and spectroscopy and combustion topics of broad general interest.

Fry, Ronald S. (Editor); Gannaway, Mary T. (Editor)

1996-01-01

258

DNS analysis of partially premixed combustion in spray and gaseousturbulent flame-bases stabilized in hot air  

Microsoft Academic Search

Direct numerical simulations of weakly turbulent-lifted flame bases\\u000d\\u000a\\u0009are examined in the case of both gaseous and spray fuel jet injection.\\u000d\\u000a\\u0009Simplified transport properties and an adjustable single-step chemistry\\u000d\\u000a\\u0009that matches the flame response to equivalence ratio are used. The\\u000d\\u000a\\u0009flames are stabilized within a coflowing stream of heated air. The\\u000d\\u000a\\u0009properties of the zone where burning starts are found

Pascale Domingo; Luc Vervisch; J. Reveillon

2005-01-01

259

Spherical combustion clouds in explosions  

NASA Astrophysics Data System (ADS)

This study explores the properties of spherical combustion clouds in explosions. Two cases are investigated: (1) detonation of a TNT charge and combustion of its detonation products with air, and (2) shock dispersion of aluminum powder and its combustion with air. The evolution of the blast wave and ensuing combustion cloud dynamics are studied via numerical simulations with our adaptive mesh refinement combustion code. The code solves the multi-phase conservation laws for a dilute heterogeneous continuum as formulated by Nigmatulin. Single-phase combustion (e.g., TNT with air) is modeled in the fast-chemistry limit. Two-phase combustion (e.g., Al powder with air) uses an induction time model based on Arrhenius fits to Boiko's shock tube data, along with an ignition temperature criterion based on fits to Gurevich's data, and an ignition probability model that accounts for multi-particle effects on cloud ignition. Equations of state are based on polynomial fits to thermodynamic calculations with the Cheetah code, assuming frozen reactants and equilibrium products. Adaptive mesh refinement is used to resolve thin reaction zones and capture the energy-bearing scales of turbulence on the computational mesh (ILES approach). Taking advantage of the symmetry of the problem, azimuthal averaging was used to extract the mean and rms fluctuations from the numerical solution, including: thermodynamic profiles, kinematic profiles, and reaction-zone profiles across the combustion cloud. Fuel consumption was limited to ˜ 60-70 %, due to the limited amount of air a spherical combustion cloud can entrain before the turbulent velocity field decays away. Turbulent kinetic energy spectra of the solution were found to have both rotational and dilatational components, due to compressibility effects. The dilatational component was typically about 1 % of the rotational component; both seemed to preserve their spectra as they decayed. Kinetic energy of the blast wave decayed due to the pressure field. Turbulent kinetic energy of the combustion cloud decayed due to enstrophy overline{? 2} and dilatation overline{? 2}.

Kuhl, A. L.; Bell, J. B.; Beckner, V. E.; Balakrishnan, K.; Aspden, A. J.

2013-05-01

260

REFERENCE GUIDELINE FOR INDUSTRIAL BOILER MANUFACTURERS TO CONTROL POLLUTION WITH COMBUSTION MODIFICATION  

EPA Science Inventory

The report describes combustion modification methods that are available to boiler manufacturers for controlling air pollutant emissions from industrial size fossil-fuel-fired steam boilers. The methods discussed include reduction of excess air, staged combustion, air register adj...

261

A fluidized-bed combustion process with inherent CO 2 separation; application of chemical-looping combustion  

Microsoft Academic Search

For combustion with CO2 capture, chemical-looping combustion has the advantage that no energy is lost for the separation of CO2. In chemical-looping combustion oxygen is transferred from the combustion air to the gaseous fuel by means of an oxygen carrier. The fuel and the combustion air are never mixed, and the gases from the oxidation of the fuel, CO2 and

Anders Lyngfelt; Bo Leckner; Tobias Mattisson

2001-01-01

262

If you interested in receiving the pdf of one or more article on this list, please send you request to Lynn Zaltsman at zaltsmanl@seas.wustl.edu  

E-print Network

(314) 935-7560 axelbaum@wustl.edu PUBLICATIONS Peer-Reviewed Articles and Book Chapters 1. Lengyel, M. and Axelbaum, R.L. "Stability of spray combustion for water/alcohols mixtures in oxygen- enriched air

Subramanian, Venkat

263

Internal combustion engine using premixed combustion of stratified charges  

DOEpatents

During a combustion cycle, a first stoichiometrically lean fuel charge is injected well prior to top dead center, preferably during the intake stroke. This first fuel charge is substantially mixed with the combustion chamber air during subsequent motion of the piston towards top dead center. A subsequent fuel charge is then injected prior to top dead center to create a stratified, locally richer mixture (but still leaner than stoichiometric) within the combustion chamber. The locally rich region within the combustion chamber has sufficient fuel density to autoignite, and its self-ignition serves to activate ignition for the lean mixture existing within the remainder of the combustion chamber. Because the mixture within the combustion chamber is overall premixed and relatively lean, NO.sub.x and soot production are significantly diminished.

Marriott, Craig D. (Rochester Hills, MI); Reitz, Rolf D. (Madison, WI

2003-12-30

264

Indoor Air Pollution from Biomass Combustion and its Adverse Health Effects in Central India: An Exposure-Response Study  

PubMed Central

Background: Some of the highest exposures to air pollutants in developing countries occur inside homes where biofuels are used for daily cooking. Inhalation of these pollutants may cause deleterious effects on health. Objectives: To assess the respiratory and other morbidities associated with use of various types of cooking fuels in rural area of Nagpur and to study the relationship between the duration of exposure (exposure index [EI]) and various morbidities. Materials and Methods: A total of 760 non-smoking, non-pregnant women aged 15 years and above (mean age 32.51 ? 14.90 years) exposed to domestic smoke from cooking fuels from an early age, working in poorly ventilated kitchen were selected and on examination presented with various health problems. Exposure was calculated as the average hours spent daily for cooking multiplied by the number of years. Symptoms were enquired by means of a standard questionnaire adopted from that of the British Medical Research Council. Lung function was assessed by the measurement of peak expiratory flow rate (PEFR). PEFR less than 80% of the predicted was considered as abnormal pulmonary function. Results and Conclusions: Symptoms like eye irritation, headache, and diminution of vision were found to be significantly higher in biomass users (P < 0.05). Abnormal pulmonary function, chronic bronchitis, and cataract in biomass users was significantly higher than other fuel users (P < 0.05). Moreover an increasing trend in prevalence of symptoms/morbid conditions was observed with increase in EI. The presence of respiratory symptoms/morbid conditions was associated with lower values of both observed and percent predicted PEFR (P < 0.05 to 0.001). Thus women exposed to biofuels smoke suffer more from health problems and respiratory illnesses when compared with other fuel users. PMID:24019602

Sukhsohale, Neelam D; Narlawar, Uday W; Phatak, Mrunal S

2013-01-01

265

Coal combustion system  

DOEpatents

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.

Wilkes, Colin (Lebanon, IN); Mongia, Hukam C. (Carmel, IN); Tramm, Peter C. (Indianapolis, IN)

1988-01-01

266

ON THE COMBUSTION CHARACTERISTICS OF SAWDUST IN A CYCLONE COMBUSTOR  

Microsoft Academic Search

This paper discusses experimental results on the combustion characteristics of sawdust in a cyclone combustor in which sawdust and air are injected into the combustion chamber through two tangential inlets. Data obtained for flow visualization under isothermal flow conditions, flame stability, combustion temperature mapping and combustion-product composition analyses are presented. It is observed that sawdust particles, except for the very

Bundit Fungtammasan; Prajak Jittrepit

267

Prediction of temperature front in a gas turbine combustion chamber  

Microsoft Academic Search

Numerical computation has been applied to investigate the temperature field in a gas turbine combustion chamber. The simulation assumed that pressure imbalance conditions of air flow between primary and secondary inlets occur. The combustion chamber under study is part of a 70MW gas turbine from an operating combined cycle power plant. The combustion was simulated with normal fuel–air flow rate

F. Z. Sierra; J. Kubiak; G. González; G. Urquiza

2005-01-01

268

Antipollution combustion chamber  

SciTech Connect

The invention concerns a combustion chamber for turbojet engines. The combustion chamber is of the annular type and consists of two coaxial flame tubes opening into a common dilution and mixing zone. The inner tube is designed for low operating ratings of the engine, the outer tube for high ratings. Air is injected as far upstream as possible into the dilution zone, to enhance the homogenization of the gaseous flow issuing from the two tubes prior to their passage into the turbine and to assure the optimum radial distribution of temperatures. The combustion chamber according to the invention finds application in a particularly advantageous manner in turbojet engines used in aircraft propulsion because of the reduced emission of pollutants it affords.

Caruel, J.E.; Gastebois, P.M.

1981-01-27

269

Catalytic combustion with steam injection  

NASA Technical Reports Server (NTRS)

The effects of steam injection on (1) catalytic combustion performance, and (2) the tendency of residual fuel to burn in the premixing duct upstream of the catalytic reactor were determined. A petroleum residual, no. 2 diesel, and a blend of middle and heavy distillate coal derived fuels were tested. Fuel and steam were injected together into the preheated airflow entering a 12 cm diameter catalytic combustion test section. The inlet air velocity and pressure were constant at 10 m/s and 600 kPa, respectively. Steam flow rates were varied from 24 percent to 52 percent of the air flow rate. The resulting steam air mixture temperatures varied from 630 to 740 K. Combustion temperatures were in the range of 1200 to 1400 K. The steam had little effect on combustion efficiency or emissions. It was concluded that the steam acts as a diluent which has no adverse effect on catalytic combustion performance for no. 2 diesel and coal derived liquid fuels. Tests with the residual fuel showed that upstream burning could be eliminated with steam injection rates greater than 30 percent of the air flow rate, but inlet mixture temperatures were too low to permit stable catalytic combustion of this fuel.

Anderson, D. N.; Tacina, R. R.

1982-01-01

270

Utilization of coal mine ventilation exhaust as combustion air in gas-fired turbines for electric and/or mechanical power generation. Semi-annual topical report, June 1995--August 1995  

SciTech Connect

Methane emitted during underground coal mining operations is a hazard that is dealt with by diluting the methane with fresh air and exhausting the contaminated air to the atmosphere. Unfortunately this waste stream may contain more than 60% of the methane resource from the coal, and in the atmosphere the methane acts as a greenhouse gas with an effect about 24.5 times greater than CO{sub 2}. Though the waste stream is too dilute for normal recovery processes, it can be used as combustion air for a turbine-generator, thereby reducing the turbine fuel requirements while reducing emissions. Preliminary analysis indicates that such a system, built using standard equipment, is economically and environmentally attractive, and has potential for worldwide application.

NONE

1995-12-01

271

Microgravity Smoldering Combustion Takes Flight  

NASA Technical Reports Server (NTRS)

The Microgravity Smoldering Combustion (MSC) experiment lifted off aboard the Space Shuttle Endeavour in September 1995 on the STS-69 mission. This experiment is part of series of studies focused on the smolder characteristics of porous, combustible materials in a microgravity environment. Smoldering is a nonflaming form of combustion that takes place in the interior of combustible materials. Common examples of smoldering are nonflaming embers, charcoal briquettes, and cigarettes. The objective of the study is to provide a better understanding of the controlling mechanisms of smoldering, both in microgravity and Earth gravity. As with other forms of combustion, gravity affects the availability of air and the transport of heat, and therefore, the rate of combustion. Results of the microgravity experiments will be compared with identical experiments carried out in Earth's gravity. They also will be used to verify present theories of smoldering combustion and will provide new insights into the process of smoldering combustion, enhancing our fundamental understanding of this frequently encountered combustion process and guiding improvement in fire safety practices.

1996-01-01

272

Promoted Combustion of Metals in a High-Pressure, Flowing Oxygen Environment  

NASA Technical Reports Server (NTRS)

Traditional promoted combustion testing has used 0.125 inch diameter samples that are ignited in a pressurized, oxygen-enriched environment. Many years of testing this sample size have yielded useful data regarding threshold pressure, or the minimum oxygen pressure required to support self-sustained combustion. However, when a material is tested in a flowing system, the threshold pressure changes. White Sands Test Facility has developed a test system to burn samples in flowing gaseous oxygen. Current sample configurations are 0.5 inch diameter rods and 1.25 inch diameter pipes with pressures ranging up to 2000 psi and gas velocities reaching 200 ft/s. This paper describes the test apparatus, modifications made as the result of a fire, and a description of the tests currently being performed.

Maes, M. J.; Stoltzfus, J. M.

2001-01-01

273

21 CFR 173.350 - Combustion product gas.  

...following prescribed conditions: (a) The food additive is manufactured by the controlled combustion in air of butane, propane, or natural gas. The combustion equipment shall be provided with an absorption-type filter capable of removing...

2014-04-01

274

Improved Combustion Efficiencies - Control Systems for Process Heaters and Boilers  

E-print Network

are discussed and the need for modern control is stressed. Modern control systems offered by leading manufacturers are discussed in detail. Modern combustion control systems are designed to provide safe and proper combustion, desired air/fuel ratio, reduced...

Varma, A. C.; Prengle, H. W.

1979-01-01

275

Flameless Combustion for Gas Turbines  

NASA Astrophysics Data System (ADS)

An experimental study of a novel flameless combustor for gas turbine engines is presented. Flameless combustion is characterized by distributed flame and even temperature distribution for high preheat air temperature and large amount of recirculating low oxygen exhaust gases. Extremely low emissions of NOx, CO, and UHC are reported. Measurements of the flame chemiluminescence, CO and NOx emissions, acoustic pressure, temperature and velocity fields as a function of the preheat temperature, inlet air mass flow rate, exhaust nozzle contraction ratio, and combustor chamber diameter are described. The data indicate that larger pressure drop promotes flameless combustion and low NOx emissions at the same flame temperature. High preheated temperature and flow rates also help in forming stable combustion and therefore are favorable for flameless combustion.

Gutmark, Ephraim; Li, Guoqiang; Overman, Nick; Cornwell, Michael; Stankovic, Dragan; Fuchs, Laszlo; Milosavljevic, Vladimir

2006-11-01

276

Controlling Indoor Air Pollution.  

ERIC Educational Resources Information Center

Discusses the health risks posed by indoor air pollutants, such as airborne combustion products, toxic chemicals, and radioactivity. Questions as to how indoor air might be regulated. Calls for new approaches to environmental protection. (TW)

Nero, Anthony V, Jr.

1988-01-01

277

Determining Heats of Combustion of Gaseous Hydrocarbons  

NASA Technical Reports Server (NTRS)

Enrichment-oxygen flow rate-ratio related to heat of combustion. Technique developed for determining heats of combustion of natural-gas samples. Based on measuring ratio m/n, where m is (volmetric) flow rate of oxygen required to enrich carrier air in which test gas flowing at rate n is burned, such that mole fraction of oxygen in combustion-product gases equals that in carrier air. The m/n ratio directly related to heats of combustion of saturated hydrocarbons present in natural gas.

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

1987-01-01

278

The effects of spark ignition parameters on the lean burn limit of natural gas combustion in an internal combustion engine  

E-print Network

A full factorial experiment was conducted to determine the effects of internal combustion engine ignition parameters on the air-fuel ratio (A/F) lean limit of combustion with compressed natural gas (CNG). Spark electrical characteristics (voltage...

Chlubiski, Vincent Daniel

2012-06-07

279

Combustion-gas recirculation system  

DOEpatents

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.

Baldwin, Darryl Dean (Lacon, IL)

2007-10-09

280

Advanced Burners and Combustion Controls for Industrial Heat Recovery Systems  

E-print Network

of the air pressure regardless of the temperature. The result is a decrease in air/fuel ratio (richer) as combustion air temperature increases and is illustrated in Figure 6. A mass flow ratio control system can be used to correct air/fuel ratios as air... of the air pressure regardless of the temperature. The result is a decrease in air/fuel ratio (richer) as combustion air temperature increases and is illustrated in Figure 6. A mass flow ratio control system can be used to correct air/fuel ratios as air...

Ferri, J. L.

281

Difference Between IR Radiation Spectra of Ethanol in Free Diffusion Combustion Regime and Regime Influenced by an Air Flow in Modeling of a Fire Tornado  

NASA Astrophysics Data System (ADS)

Results of experimental investigations of liquid fuel combustion in the regime of a twisted jet (model of a fire tornado) are presented. Flame radiation spectra were registered. In the chosen spectral range of registration (2.2-4.8 ?m), six spectral intervals were clearly traced in which the main portion of radiated energy was concentrated. Using the ratio of the sums of spectral intensities in the vicinities of the 6th and 3rd maxima, we successfully distinguished the regimes of modeled fire tornado and free diffusion fuel combustion.

Sherstobitov, M. V.; Tsvyk, R. Sh.

2013-06-01

282

Survey of Hydrogen Combustion Properties  

NASA Technical Reports Server (NTRS)

This literature digest of hydrogen-air combustion fundamentals presents data on flame temperature, burning velocity, quenching distance, flammability limits, ignition energy, flame stability, detonation, spontaneous ignition, and explosion limits. The data are assessed, recommended values are given, and relations among various combustion properties are discussed. New material presented includes: theoretical treatment of variation in spontaneous ignition lag with temperature, pressure, and composition, based on reaction kinetics of hydrogen-air composition range for 0.01 to 100 atmospheres and initial temperatures of 0 degrees to 1400 degrees k.

Drell, Isadore L; Belles, Frank E

1958-01-01

283

COâ emission abatement in IGCC power plants by semiclosed cycles: Part B -- With air-blown combustion and COâ physical absorption  

Microsoft Academic Search

This paper analyzes the fundamentals of IGCC power plants with carbon dioxide removal systems, by a cycle configuration alternative to the one discussed in Part A (with oxygen-blown combustion). The idea behind this proposal is to overcome the major drawbacks of the previous solution (large oxygen consumption and re-design of the gas turbine unit), by means of a semiclosed cycle

P. Chiesa; G. Lozza

1999-01-01

284

Injection, atomization, ignition and combustion of liquid fuels in high-speed air streams. Annual scientific report 1 December 81-31 December 82  

Microsoft Academic Search

A simulation approach to studying hot flow subsonic cross-stream fuel injection problems in a less complex and costly cold flow facility was developed. A typical ramjet combustion chamber fuel injection problem was posed where ambient temperature fuel (Kerosene) is injected into a hot airstream. This case was transformed through two new similarity parameters involving injection and freestream properties to a

Schetz

1983-01-01

285

Shortcomings in USEPA's Approach for Predicting Risk Due to Consumption of Animal Food Products Impacted by Air Emissions from Hazardous Waste Combustion Facilities: A Case Study Involving Phthalates  

Microsoft Academic Search

As a part of the permitting process for hazardous waste combustion facilities, regulatory agencies are now conducting site-specific, multipathway risk assessments. In accordance with the approach established by the USEPA, the Texas Natural Resource Conservation Commission uses a prospective risk assessment paradigm whereby site-specific activity pattern and land use information is used to determine plausible exposure scenarios and pathways. A

Roberta L. Grant; Rosita J. Rodriguez; Chris S. Hofelt; Laurie C. Haws

2002-01-01

286

Jet plume injection and combustion system for internal combustion engines  

DOEpatents

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.

Oppenheim, Antoni K. (Kensington, CA); Maxson, James A. (Berkeley, CA); Hensinger, David M. (Albany, CA)

1993-01-01

287

Jet plume injection and combustion system for internal combustion engines  

DOEpatents

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.

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

1993-12-21

288

Biofuels Combustion  

NASA Astrophysics Data System (ADS)

This review describes major features of current research in renewable fuels derived from plants and from fatty acids. Recent and ongoing fundamental studies of biofuel molecular structure, oxidation reactions, and biofuel chemical properties are reviewed, in addition to combustion applications of biofuels in the major types of engines in which biofuels are used. Biofuels and their combustion are compared with combustion features of conventional petroleum-based fuels. Two main classes of biofuels are described, those consisting of small, primarily alcohol, fuels (particularly ethanol, n-butanol, and iso-pentanol) that are used primarily to replace or supplement gasoline and those derived from fatty acids and used primarily to replace or supplement conventional diesel fuels. Research efforts on so-called second- and third-generation biofuels are discussed briefly.

Westbrook, Charles K.

2013-04-01

289

Biofuels combustion.  

PubMed

This review describes major features of current research in renewable fuels derived from plants and from fatty acids. Recent and ongoing fundamental studies of biofuel molecular structure, oxidation reactions, and biofuel chemical properties are reviewed, in addition to combustion applications of biofuels in the major types of engines in which biofuels are used. Biofuels and their combustion are compared with combustion features of conventional petroleum-based fuels. Two main classes of biofuels are described, those consisting of small, primarily alcohol, fuels (particularly ethanol, n-butanol, and iso-pentanol) that are used primarily to replace or supplement gasoline and those derived from fatty acids and used primarily to replace or supplement conventional diesel fuels. Research efforts on so-called second- and third-generation biofuels are discussed briefly. PMID:23298249

Westbrook, Charles K

2013-01-01

290

EGR control device for internal combustion engine  

Microsoft Academic Search

This patent describes an EGR control device for an internal combustion engine comprising an EGR control valve installed in EGR passageway communicating with an exhaust system and an intake system of an internal combustion engine, an oxygen sensor for detecting the oxygen content of the intake air installed in the downstream of the opening of the EGR passageway in the

M. Nishida; N. Inoue; Y. Asayama; H. Suzuki

1988-01-01

291

Turbulent Combustion in SDF Explosions  

SciTech Connect

A heterogeneous continuum model is proposed to describe the dispersion and combustion of an aluminum particle cloud in an explosion. It combines the gas-dynamic conservation laws for the gas phase with a continuum model for the dispersed phase, as formulated by Nigmatulin. Inter-phase mass, momentum and energy exchange are prescribed by phenomenological models. It incorporates a combustion model based on the mass conservation laws for fuel, air and products; source/sink terms are treated in the fast-chemistry limit appropriate for such gasdynamic fields, along with a model for mass transfer from the particle phase to the gas. The model takes into account both the afterburning of the detonation products of the C-4 booster with air, and the combustion of the Al particles with air. The model equations were integrated by high-order Godunov schemes for both the gas and particle phases. Numerical simulations of the explosion fields from 1.5-g Shock-Dispersed-Fuel (SDF) charge in a 6.6 liter calorimeter were used to validate the combustion model. Then the model was applied to 10-kg Al-SDF explosions in a an unconfined height-of-burst explosion. Computed pressure histories are compared with measured waveforms. Differences are caused by physical-chemical kinetic effects of particle combustion which induce ignition delays in the initial reactive blast wave and quenching of reactions at late times. Current simulations give initial insights into such modeling issues.

Kuhl, A L; Bell, J B; Beckner, V E

2009-11-12

292

Solvent and pressure influences on air separation of liquid crystalline triheptyl cellulose composite ethyl cellulose membranes  

SciTech Connect

Air separation of a cholesteric liquid crystalline triheptyl cellulose/ethyl cellulose (3/97) binary composite membrane prepared from tetrahydrofuran, chloroform, and dichloromethane solutions was studied at different pressure differences across the membrane by the variable volume method. With an increasing pressure difference in the range from 0.06 to 0.42 MPa, the flux and the oxygen concentration of the oxygen-enriched air through the membrane both increase. The air separation capability depends on the boiling point of the membrane-forming solvent and the membrane thickness. 15 refs., 4 figs., 1 tab.

Li, X.G.; Huang, M.R.; Lin, G.; Yang, P.C. (Tianjin Inst. of Textile Science and Technology (China))

1994-03-01

293

Theoretical nitric oxide production incidental to autoignition and combustion of several fuels homogeneously dispersed in air under some typical hypersonic flight conditions  

NASA Technical Reports Server (NTRS)

A reaction package of 100 chemical reactions and attendant reaction rate constants defined for the autoignition and combustion of four carbonaceous fuels, CH4, CH3OH, C2H6, and C2H5OH. Definition of the package was made primarily by means of comparison between trial calculations and experimental data for the autoignition of CH4. Autoignition and combustion of each of these four fuels was calculated under three sets of conditions realistic for hypersonic flight applications, for comparison to hydrogen fuel, particularly with respect to formation of nitric oxide. Results show that, for all of the fuels including hydrogen, if NO production is a significant problem, compromise must be made between approaching equilibrium heat release and approaching equilibrium NO concentration.

Bahn, G. S.

1974-01-01

294

Stabilization of propane combustion in a supersonic air flow using a nonequilibrium longitudinal discharge and a coaxial local low-pressure zone  

Microsoft Academic Search

The results of the experimental investigation of the flow in the vicinity of an electric-discharge module having a low aerodynamic\\u000a drag and intended for igniting hydrocarbon fuel and stabilizing its burning in a supersonic flow at low initial static temperature\\u000a and pressure are presented. The distinctive feature of the module is that the combustion zone is not attached to the

B. G. Efimov; V. V. Ivanov; V. V. Skvortsov; M. A. Starodubtsev

2010-01-01

295

Turbulent combustion  

SciTech Connect

Turbulent combustion is the dominant process in heat and power generating systems. Its most significant aspect is to enhance the burning rate and volumetric power density. Turbulent mixing, however, also influences the chemical rates and has a direct effect on the formation of pollutants, flame ignition and extinction. Therefore, research and development of modern combustion systems for power generation, waste incineration and material synthesis must rely on a fundamental understanding of the physical effect of turbulence on combustion to develop theoretical models that can be used as design tools. The overall objective of this program is to investigate, primarily experimentally, the interaction and coupling between turbulence and combustion. These processes are complex and are characterized by scalar and velocity fluctuations with time and length scales spanning several orders of magnitude. They are also influenced by the so-called {open_quotes}field{close_quotes} effects associated with the characteristics of the flow and burner geometries. The authors` approach is to gain a fundamental understanding by investigating idealized laboratory flames. Laboratory flames are amenable to detailed interrogation by laser diagnostics and their flow geometries are chosen to simplify numerical modeling and simulations and to facilitate comparison between experiments and theory.

Talbot, L.; Cheng, R.K. [Lawrence Berkeley Laboratory, CA (United States)

1993-12-01

296

2002 Spring Technical Meeting Central States Section / The Combustion Institute  

E-print Network

Motors Research & Development Center Local Fuel-Air Ratio Measurements in Internal Combustion Engines Research Laboratory A Multi-dimensional Combustion Model for Gasoline Direct-Injection Engine Design 10 Emissions from Small Utility Engines 12:00 PM Lunch & Business Meeting SESSION A.2: Multiphase Combustion

Tennessee, University of

297

A Study of In Situ Combustion in a Segregated System  

Microsoft Academic Search

Some of the field pilot studies made to date have indicated that forward combustion proceeds in a segregated manner in oil reservoirs and that surfaces at which combustion is occurring develop both parallel and perpendicular to the general direction of air injection. Although mathematical studies of combustion in a segregated system have been made, no experiments involving such a system

Chakib Khelil

1969-01-01

298

Post-Combustion CO2 Capture 11 -13 July 2010  

E-print Network

Post-Combustion CO2 Capture Workshop 11 - 13 July 2010 Tufts European Center Talloires, France Institute | | Clean Air Task Force | | Asia Clean Energy Innovation Initiative | #12;Post-Combustion CO2 Capture Workshop 11 - 13 July 2010 Talloires, France PROCEEDINGS: Post-Combustion CO2 Capture Workshop

299

Catalyzing the Combustion of Coal  

NASA Technical Reports Server (NTRS)

Reaction rate of coal in air can be increased by contacting or coating coal with compound such as calcium acetate. The enhanced reaction rate generates more heat, reducing furnace size. Increase in combustion rate is about 26 percent, and internal pollutants in powerplant are reduced.

Humphrey, M. F.; Dokko, W.

1982-01-01

300

Modelling Spontaneous Combustion of Coal  

Microsoft Academic Search

Spontaneous combustion of coal is an important problem in mining and storage, in terms of both safety and economics. This is because coal reacts with oxygen in the air and an exothermic reaction occurs, even in ambient conditions. The heat of the reaction accumulates and the reaction becomes progressively faster and thermal runaway may take place to the point of

Ahmet ARISOY; B. Basil BEAMISH

301

INDUCED SECONDARY COMBUSTION IN WOODSTOVES  

EPA Science Inventory

The paper provides information useful for woodstove designers concerned with reducing emissions. A dual-chamber woodstove was modified to induce secondary combustion by utilizing an ignition source and forced flow of secondary air. The ignition source was an electric glow plug in...

302

Energy conservation in industrial operations - method and economics of improved combustion efficiencies. Topical report. Combustion-control systems for process heaters and boilers  

Microsoft Academic Search

The importance and applications of modern combustion control systems for retrofitting existing boilers and heaters to increase combustion efficiency are discussed. The conventionally used heater control system and its deficiencies are discussed in detail and the need for modern control systems is stressed. Modern combustion control systems are designed to provide safe and efficient combustion and desired air\\/fuel ratio, reducing

A. C. Varma; H. W. Jr. Prengle

1979-01-01

303

Preparation and characterization of nano- and non-nanoscale Co?O? spinels obtained from different methods and study of their performance in combustion of aromatics from polluted air-A comparison with Pt/?-Al?O? performance.  

PubMed

This article reports the development of oxidative precipitation (OP) method for synthesis of Co(3)O(4) as an environmental catalyst and comparison of its performance with that of obtained from conventional sol gel combustion (SG) method and industrial Pt/?-Al(2)O(3) in remediation of toluene from air. Catalytic studies were carried out in a fixed bed reactor at 100-350°C under atmospheric pressure. Co(3)O(4) (OP) showed the highest activity in combustion of toluene. The half conversion temperature of toluene (T(50%)) was 160, 258, and 229°C on Co(3)O(4) (OP), Co(3)O(4) (SG) and Pt/?-Al(2)O(3), respectively. The higher activity of Co(3)O(4) (OP) was ascribed to nanostructure and reducibility of catalytic sites at lower temperatures, approved by TPR results. The study confirmed that preparation method has a large influence on the chemical-physical properties and activity of the catalyst. The study indicated that oxidative precipitation method could be a promising method to synthesize environmental catalysts considering the simplicity and needless to calcine catalyst at higher temperatures. PMID:22755518

Hosseini, Seyedali; Niaei, Aligholi; Salari, Dariush

2012-01-01

304

Advanced Combustion  

SciTech Connect

The activity reported in this presentation is to provide the mechanical and physical property information needed to allow rational design, development and/or choice of alloys, manufacturing approaches, and environmental exposure and component life models to enable oxy-fuel combustion boilers to operate at Ultra-Supercritical (up to 650{degrees}C & between 22-30 MPa) and/or Advanced Ultra-Supercritical conditions (760{degrees}C & 35 MPa).

Holcomb, Gordon R. [NETL

2013-03-11

305

MONITORING STRATEGIES FOR FLUIDIZED BED COMBUSTION COAL PLANTS  

EPA Science Inventory

Air and water monitoring strategies for commercial-size Fluidized Bed Combustion (FBC) coal plants are presented. This is one of five reports developing air and water monitoring strategies for advanced coal combustion (FBC), coal conversion (coal gasification and liquefaction), a...

306

APPLICATION OF COMBUSTION MODIFICATIONS TO INDUSTRIAL COMBUSTION EQUIPMENT (DATA SUPPLEMENT A)  

EPA Science Inventory

The supplement provides raw data from a study of the effects of combustion modifications on air pollutant emissions from a variety of industrial combustion equipment. Tested were 22 units, including refinery process heaters; clay and cement kilns; steel and aluminum furnaces; boi...

307

APPLICATION OF COMBUSTION MODIFICATIONS TO INDUSTRIAL COMBUSTION EQUIPMENT (DATA SUPPLEMENT B)  

EPA Science Inventory

The supplement provides raw data from a study of the effects of combustion modifications on air pollutant emissions from a variety of industrial combustion equipment. Tested were 22 units, including refinery process heaters; clay and cement kilns; steel and aluminum furnaces; boi...

308

Energy Efficient Process Heating: Managing Air Flow Kevin Carpenter and Kelly Kissock  

E-print Network

inlet combustion air consists of fundamental heat exchanger and combustion efficiency equations as combustion air, ventilation air, and infiltration air. Figure 1 shows a process heating system with the majorEnergy Efficient Process Heating: Managing Air Flow Kevin Carpenter and Kelly Kissock Department

Kissock, Kelly

309

Stationary Engineers Apprenticeship. Related Training Modules. 16.1-16.5 Combustion.  

ERIC Educational Resources Information Center

This learning module, one in a series of 20 related training modules for apprentice stationary engineers, deals with combustion. Addressed in the individual instructional packages included in the module are the following topics: the combustion process, types of fuel, air and flue gases, heat transfer during combustion, and wood combustion. Each…

Lane Community Coll., Eugene, OR.

310

E-Alerts: Combustion, engines, and propellants (reciprocation and rotating combustion engines). E-mail newsletter  

SciTech Connect

Design, performance, and testing of reciprocating and rotating engines of various configurations for all types of propulsion. Includes internal and external combustion engines; engine exhaust systems; engine air systems components; engine structures; stirling and diesel engines.

NONE

1999-04-01

311

Mass air flow meter  

Microsoft Academic Search

This patent describes improvement in a mass air flow meter for internal combustion engines having a hollow elongated body having a venturi therein, a sample tube associated with the body for receiving a flow of sample air therethrough, the entire air source for an engine being split into a main flow path through the venturi and into a sampling path

1991-01-01

312

Oscillating combustion from a premix fuel nozzle  

SciTech Connect

Stringent emissions requirements for stationary gas turbines have produced new challenges in combustor design. In the past, very low NOx pollutant emissions have been achieved through various combustion modifications, such as steam or water injection, or post-combustion cleanup methods such as selective catalytic reduction (SCR). An emerging approach to NOx abatement is lean premix combustion. Lean premix combustion avoids the cost and operational problems associated with other NOx control methods. By premixing fuel and air at very low equivalence ratios, the high temperatures which produce NOx are avoided. The challenges of premix combustion include avoiding flashback, and ensuring adequate fuel/air premixing. In addition, the combustion must be stable. The combustor should not operate so close to extinction that a momentary upset will extinguish the flame (static stability), and the flame should not oscillate (dynamic stability). Oscillations are undesirable because the associated pressure fluctuations can shorten component lifetime. Unfortunately, experience has shown that premix fuel nozzles burning natural gas are susceptible to oscillations. Eliminating these oscillations can be a costly and time consuming part of new engine development. As part of the U.S. Department of Energy`s Advanced Turbine Systems Program, the Morgantown Energy Technology Center (METC) is investigating the issue of combustion oscillations produced by lean premix fuel nozzles. METC is evaluating various techniques to stabilize oscillating combustion in gas turbines. Tests results from a premix fuel nozzle using swirl stabilization and a pilot flame are reported here.

Richards, G.A.; Yip, M.J.

1995-08-01

313

Got Dirty Air?  

NSDL National Science Digital Library

Students are introduced to the concepts of air pollution and technologies that have been developed by engineers to reduce air pollution. Students develop an understanding of visible air pollutants with an incomplete combustion demonstration, a "smog in a jar" demonstration, construction of simple particulate matter collectors and by exploring engineering roles related to air pollution. Next, students develop awareness and understanding of the daily air quality and trends in air quality using the Air Quality Index (AQI) listed in the newspaper. Finally, students build and observe a variety of simple models in order to develop an understanding of how engineers use these technologies to clean up and prevent air pollution.

Integrated Teaching And Learning Program

314

Meteorological Effects on Air/Fuel Ratio  

E-print Network

METEOROLOGICAL EFFECTS ON AIR/FUEL RATIO John L. Ferri GTE Products Corporation Towanda, Pennsylvania ABSTRACT Air is a convenient and inexpensive source of oxygen for most combustion processes. However, the oxygen content of the air...METEOROLOGICAL EFFECTS ON AIR/FUEL RATIO John L. Ferri GTE Products Corporation Towanda, Pennsylvania ABSTRACT Air is a convenient and inexpensive source of oxygen for most combustion processes. However, the oxygen content of the air...

Ferri, J. L.

1984-01-01

315

Biomass Burning versus Fossil Fuel Combustion Signatures of Air Masses Transported from Asia to the U.S. West Coast during ITCT2k2  

Microsoft Academic Search

The goal of the Intercontinental Transport and Chemical Transformation experiment in 2002 (ITCT2k2) was to study the transport of air pollution from Asia across the Pacific Ocean, and the implications for the background atmospheric composition at the surface in North America. During research flights of the NOAA WP-3 research aircraft on May 5 and 17, strong enhancements of carbon monoxide

J. de Gouw; O. Cooper; C. Warneke; P. Hudson; C. Brock; F. Fehsenfeld; J. Holloway; G. Huebler; D. Murphy; J. Nowak; D. Parrish; T. Ryerson; E. Atlas

2003-01-01

316

Development of Electrophoretic Process for Coating T-53 Air Diffuser, Exhaust Diffuser, and Combustion Chamber Housing with 'Sermetel (Trade Name) W'.  

National Technical Information Service (NTIS)

This report covers activities accomplished during Phase IV of a ten (10) month program to develop an electrophoretic coating method for the application of a corrosion-resistant coating to all critical surfaces of the exhaust diffuser, air diffuser and com...

K. A. Gebler

1968-01-01

317

A car air-conditioning system based on an absorption refrigeration cycle using energy from exhaust gas of an internal combustion engine  

Microsoft Academic Search

Energy from the exhaust gas of an internal combus- tion engine is used to power an absorption refriger- ation system to air-condition an ordinary passenger car. The theoretical design is verified by a unit that is tested under both laboratory and road-test condi- tions. For the latter, the unit is installed in a Nissan 1400 truck and the results indicate

G Vicatos; J Gryzagoridis; S Wang

2008-01-01

318

Noncircular jets in combustion systems  

SciTech Connect

Combustion dynamics of burners with corners were studied using Planar Laser Induced Fluorescence (PLIF). The same effect of sharp corners on the air flow dynamics, shown earlier in cold flow tests, was found in the reacting flow of a flame. The sharp corners interrupted the coherent structures generated in an axisymmetric shear flow. The combustion at the flat sections of the flame occurred in periodic, coherent large scale structures, but was continuous and homogeneous in the vertices' sections. The azimuthal structure of the noncircular flame changed in a similar pattern as in nonreacting flows. Combined regions of small and large scale mixing in the same flow, a unique feature of burners having sharp corners, are beneficial for combustion applications. 14 references.

Gutmark, E.; Schadow, K.C.; Parr, T.P.; Parr, D.M.; Wilson, K.J.

1987-06-01

319

Combustion selective temperature dilution  

SciTech Connect

In a gas turbine engine having a hot gas flowing in an annular path partially defined by inner and outer liners of a combustor and inner and outer vane shrouds, the combustor including at its upstream end injectors for admitting an original mixture of air and fuel to the upstream end of the combustor for burning of the mixture in the combustor, the improvement is described comprising: circumferentially spaced-apart stationary turbine vanes disposed in the hot gas flow path downstream of the combustor; circumferentially spaced-apart dilution apertures disposed in the combustor downstream of the injectors, upstream of the turbine vanes and in axial alignment with leading edges of the turbine vanes, for admitting dilution air into the combustor for mixing with the original mixture to promote partial mixing thereof; and circumferentially spaced dilution apertures for admitting dilution air into the combustor to promote partial mixing with the original mixture. The first and second apertures are axially located in a secondary combustion zone of the combustor and upstream of the turbine vanes to induce partial mixing of the dilution air with the hot gases for generating a preselected circumferential temperature gradient in the hot gas for providing a flow of hot gas at a relatively higher temperature through the gaps and a flow of hot gas at relatively lower temperature upon the turbine vanes.

Vdoviak, J.W.; Weinstein, B.

1988-03-29

320

Internal combustion engine  

SciTech Connect

An internal combustion engine is disclosed which includes active cylinders being always active and inactive cylinders being inactive when the engine load is below a predetermined value. The engine has an intake passage divided into first and second branches connected to active and inactive cylinders, respectively. The second branch is provided near its inlet with a stop valve and is connected through an egr valve to the engine exhaust passage and also through an air valve to air source. A sensor is located in the exhaust passage for providing a feedback signal to ensure that the fuel supplied to the engine is maintained at a desired air/fuel ratio. Control means is provided to close the stop valve, open the egr valve, and cut off the flow of fuel for the inactive cylinders. Means is provided to close the egr valve, open the air valve, and determined the amount of fuel to the engine regardless of the feedback signal from the sensor under extremely low load conditions.

Etoh, Y.; Tanaka, T.

1982-03-23

321

Air pollution from aircraft  

NASA Technical Reports Server (NTRS)

A series of fundamental problems related to jet engine air pollution and combustion were examined. These include soot formation and oxidation, nitric oxide and carbon monoxide emissions mechanisms, pollutant dispension, flow and combustion characteristics of the NASA swirl can combustor, fuel atomization and fuel-air mixing processes, fuel spray drop velocity and size measurement, ignition and blowout. A summary of this work, and a bibliography of 41 theses and publications which describe this work, with abstracts, is included.

Heywood, J. B.; Fay, J. A.; Chigier, N. A.

1979-01-01

322

Pressurized Fluidized Bed Combustion of Sewage Sludge  

NASA Astrophysics Data System (ADS)

A conceptual design of an energy recovering system from sewage sludge was proposed. This system consists of a pressurized fluidized bed combustor, a gas turbine, and a heat exchanger for preheating of combustion air. Thermal efficiency was estimated roughly as 10-25%. In order to know the combustion characteristics of the sewage sludge under the elevated pressure condition, combustion tests of the dry and wet sewage sludge were carried out by using laboratory scale pressurized fluidized bed combustors. Combustibility of the sewage sludge was good enough and almost complete combustion was achieved in the combustion of the actual wet sludge. CO emission and NOx emission were marvelously low especially during the combustion of wet sewage sludge regardless of high volatile and nitrogen content of the sewage sludge. However, nitrous oxide (N2O) emission was very high. Hence, almost all nitrogen oxides were emitted as the form of N2O. From these combustion tests, we judged combustion of the sewage sludge with the pressurized fluidized bed combustor is suitable, and the conceptual design of the power generation system is available.

Suzuki, Yoshizo; Nojima, Tomoyuki; Kakuta, Akihiko; Moritomi, Hiroshi

323

Effect of Air-Flow Distribution and Total-Pressure Loss on Performance of One-Sixth Segment of Turbojet Combuster  

NASA Technical Reports Server (NTRS)

An investigation has been conducted on a one-sixth segment of an annular turbojet combustor to determine the effects of modification in air-flow distribution and total-pressure loss on the performance of the segment. The performance features investigated during this series of determinations were the altitude operational limits and the temperature-rise efficiency. Altitude operational limits of the combustor segment, for the 19XB engine using the original combustor-basket design were approximately 38,000 feet at 17,000 rpm and 26,000 feet at 10,000 rpm. The altitude operational limits were approximately 50,000 feet at 17,000 rpm and 38,000 feet at 10,000 rpm for a combustor-basket design in which the air-passage area in the basket was redistributed so as to admit gradually no more than 20 percent of the air along the first half of the basket. In this case the total pressure loss through the combustor segment was not appreciably changed from the total-pressure loss for the original combustor basket design. Altitude operational limits of the combustor segment for the 19XB engine were above 52,000 feet at 17,000 rpm and were approximately 23,000 feet at 10,000 rpm for a combustor-basket design in which the distribution of the air-passage area in the basket was that of the original design but where the total-pressure loss was increased to 19 times the inlet reference kinetic pressure at an inlet-to-outlet density ratio of 2.4. The total-pressure loss for the original design was 14 times the inlet kinetic reference pressure at an inlet-to-outlet density ratio of 2.4.

Hill, Francis U.; Mark, Herman

1947-01-01

324

The reduction of gas phase air toxics from combustion and incineration sources using the GE-MITSUI-BE activated coke process  

SciTech Connect

The dry desulfurization, denitrification and air toxics removal process using activated coke (AC) was originally researched and developed during the 1960s by Bergbau Forschung (BF), now called Deutsche Montan Technologies. Mitsui Mining Company (MMC) signed a licensing agreement with BF in 1982 to investigate, test and adapt the system to the facilities in Japan. Japanese regulations are stricter than in the U.S. toward SO{sub x}/NO{sub x} pollutants, as well as flyash emissions from the utility industry, oil refineries and other industries. This process is installed on flour coal-fired boilers and Fluidized Catalytic Cracker (FCC) units. These plants were constructed by MCC in Japan and Uhde GmbH in Germany. General Electric Environmental Systems, Inc. (GEESI) signed a license agreement in 1992 with MMC and Mitsui and Company, Ltd. of Tokyo. Under this agreement, GEESI will market, design, fabricate and install the Mitsui-BF press for flue gas cleaning applications in North America. MMC also developed a technology to produce AC used in the dry DeSO{sub x}/DeNO{sub x}/Air Toxics removal process based on their own metallurgical coke manufacturing technology. This paper provides information on the details of MMC`s AC used in the dry DeSO{sub x}/DeNO{sub x}/Air Toxics removal process.

Olson, D.G. [GE Environmental Systems, Lebanon, PA (United States)

1995-12-31

325

Combustion chemistry  

SciTech Connect

This research is concerned with the development and use of sensitivity analysis tools to probe the response of dependent variables to model input variables. Sensitivity analysis is important at all levels of combustion modeling. This group`s research continues to be focused on elucidating the interrelationship between features in the underlying potential energy surface (obtained from ab initio quantum chemistry calculations) and their responses in the quantum dynamics, e.g., reactive transition probabilities, cross sections, and thermal rate coefficients. The goals of this research are: (i) to provide feedback information to quantum chemists in their potential surface refinement efforts, and (ii) to gain a better understanding of how various regions in the potential influence the dynamics. These investigations are carried out with the methodology of quantum functional sensitivity analysis (QFSA).

Brown, N.J. [Lawrence Berkeley Laboratory, CA (United States)

1993-12-01

326

Dynamic stability, blowoff, and flame characteristics of oxy-fuel combustion  

E-print Network

Oxy-fuel combustion is a promising technology to implement carbon capture and sequestration for energy conversion to electricity in power plants that burn fossil fuels. In oxy-fuel combustion, air separation is used to ...

Shroll, Andrew Philip

2011-01-01

327

73 FR 3568 - Standards of Performance for Stationary Spark Ignition Internal Combustion Engines and National...  

Federal Register 2010, 2011, 2012, 2013

...as appropriate. Combustion turbine means all equipment, including but not limited to the turbine, the fuel, air, lubrication and exhaust gas systems, control systems...any simple cycle combustion turbine, any...

2008-01-18

328

71 FR 33804 - Standards of Performance for Stationary Spark Ignition Internal Combustion Engines and National...  

Federal Register 2010, 2011, 2012, 2013

...as appropriate. Combustion turbine means all equipment, including but not limited to the turbine, the fuel, air, lubrication and exhaust gas systems, control systems...any simple cycle combustion turbine, any...

2006-06-12

329

Solid waste combustion for alpha waste incineration  

SciTech Connect

Radioactive waste incinerator development at the Savannah River Laboratory has been augmented by fundamental combustion studies at the University of South Carolina. The objective was to measure and model pyrolysis and combustion rates of typical Savannah River Plant waste materials as a function of incinerator operating conditions. The analytical models developed in this work have been incorporated into a waste burning transient code. The code predicts maximum air requirement and heat energy release as a function of waste type, package size, combustion chamber size, and temperature. Historically, relationships have been determined by direct experiments that did not allow an engineering basis for predicting combustion rates in untested incinerators. The computed combustion rates and burning times agree with measured values in the Savannah River Laboratory pilot (1 lb/hr) and full-scale (12 lb/hr) alpha incinerators for a wide variety of typical waste materials.

Orloff, D.I.

1981-02-01

330

Waste combustion in boilers and industrial furnaces  

SciTech Connect

This publication contains technical papers published as they were presented at a recent specialty conference sponsored by the Air & Waste Management Association, titled Waste Combustion in Boilers and Industrial Furnaces, held March 26-27, 1996, in Kansas City, Missouri. Papers touch on compilance concerns for air pollution, air monitoring methodologies, risk assessment, and problems related to public anxiety. Separate abstracts have been indexed into the database from this proceedings.

NONE

1996-12-31

331

31st JANNAF Combustion Subcommittee Meeting. Volume 2  

NASA Technical Reports Server (NTRS)

This volume, the second of four volumes, is a collection of 36 unclassified/unlimited papers which were presented at the 31st Joint Army-Navy-NASA-Air Force (JANNAF) Combustion Subcommittee Meeting in conjunction with the Exhaust Plume Technology Subcommittee and SPIRITS User Group Meeting held 17-21 October 1994 at the Lockheed Missiles and Space Company, Sunnyvale, California. Specific subjects discussed include solid propellant combustion instability and unsteady combustion, rocket motors, guns and marine combustion characteristics, solid propellant formulation and solid and gas phase combustion kinetics.

Gannaway, Mary T. (editor)

1994-01-01

332

Review of problems in application of supersonic combustion  

NASA Technical Reports Server (NTRS)

The problem of air-breathing engines capable of flying at very high Mach numbers is described briefly. Possible performance of supersonic combustion ramjets is outlined briefly and the supersonic combustion process is described. Two mechanisms of combustion are outlined: one is supersonic combustion controlled by convection process, and the second is controlled by diffusion. The parameters related to the combustion process are discussed in detail. Data and analyses of reaction rates and mixing phenomena are represented; the flame mechanism is discussed, and experimental results are presented.

Ferri, A.

1977-01-01

333

On-line measurement of heat of combustion  

NASA Technical Reports Server (NTRS)

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.

Chaturvedi, S. K.; Chegini, H.

1988-01-01

334

Straw combustion in a fixed bed combustor  

Microsoft Academic Search

Straw and herbaceous energy crops are key biomass materials for greenhouse gas neutral energy production. Combustion of straw and two herbaceous crops was investigated in a fixed-bed reactor for a range of air flow-rates (234–1170kg\\/m2h). The fixed bed tests simulate the moving bed combustion where the distance along a grate corresponds to the time on the fixed bed. Measured temperatures,

Adela Khor; Changkook Ryu; Yao-bin Yang; Vida N. Sharifi; Jim Swithenbank

2007-01-01

335

Internal combustion engine and method for control  

DOEpatents

In one exemplary embodiment of the invention an internal combustion engine includes a piston disposed in a cylinder, a valve configured to control flow of air into the cylinder and an actuator coupled to the valve to control a position of the valve. The internal combustion engine also includes a controller coupled to the actuator, wherein the controller is configured to close the valve when an uncontrolled condition for the internal engine is determined.

Brennan, Daniel G

2013-05-21

336

An approach to optimum combustion control using parallel type and cross-limiting type technique  

Microsoft Academic Search

In the paper, a new approach to the combustion control by introducing the parallel type air–fuel combustion control and cross-limiting type (or lead-lag type) combustion control technique designed in one control system in a boiler is presented. This new approached combustion control system is designed in such way that controlled the air–fuel ratio in furnace in parallel way for small

Madan Bhowmick; Satish Chandra Bera

337

Combustion Byproducts Recycling Consortium  

SciTech Connect

Each year, over 100 million tons of solid byproducts are produced by coal-burning electric utilities in the United States. Annual production of flue gas desulfurization (FGD) byproducts continues to increase as the result of more stringent sulfur emission restrictions. In addition, stricter limits on NOx emissions mandated by the 1990 Clean Air Act have resulted in utility burner/boiler modifications that frequently yield higher carbon concentrations in fly ash, which restricts the use of the ash as a cement replacement. Controlling ammonia in ash is also of concern. If newer, “clean coal” combustion and gasification technologies are adopted, their byproducts may also present a management challenge. The objective of the Combustion Byproducts Recycling Consortium (CBRC) is to develop and demonstrate technologies to address issues related to the recycling of byproducts associated with coal combustion processes. A goal of CBRC is that these technologies, by the year 2010, will lead to an overall ash utilization rate from the current 34% to 50% by such measures as increasing the current rate of FGD byproduct use and increasing in the number of uses considered “allowable” under state regulations. Another issue of interest to the CBRC would be to examine the environmental impact of both byproduct utilization and disposal. No byproduct utilization technology is likely to be adopted by industry unless it is more cost-effective than landfilling. Therefore, it is extremely important that the utility industry provide guidance to the R&D program. Government agencies and privatesector organizations that may be able to utilize these materials in the conduct of their missions should also provide input. The CBRC will serve as an effective vehicle for acquiring and maintaining guidance from these diverse organizations so that the proper balance in the R&D program is achieved.

Ziemkiewicz, Paul; Vandivort, Tamara; Pflughoeft-Hassett, Debra; Chugh, Y Paul; Hower, James

2008-08-31

338

Characteristics of non-premixed oxygen-enhanced combustion: I. The presence of appreciable oxygen at the location of maximum temperature  

SciTech Connect

The presence of appreciable molecular oxygen at the location of maximum temperature has been observed in non-premixed oxygen-enhanced combustion (OEC) processes, specifically in flames having a high stoichiometric mixture fraction (Z{sub st}) produced with diluted fuel and oxygen-enrichment. For conventional fuel-air flames, key features of the flame are consistent with the flame sheet approximation (FSA). In particular, the depletion of O{sub 2} at the location of maximum temperature predicted by the FSA correlates well with the near-zero O{sub 2} concentration measured at this location for conventional fuel-air flames. In contradistinction, computational analysis with detailed kinetics demonstrates that for OEC flames at high Z{sub st}: (1) there is an appreciable concentration of O{sub 2} at the location of maximum temperature and (2) the maximum temperature is not coincident with the location of global stoichiometry, O{sub 2} depletion, or maximum heat release. We investigate these phenomena computationally in three non-premixed ethylene flames at low, moderate, and high Z{sub st}, but with equivalent adiabatic flame temperatures. Results demonstrate that the location of O{sub 2} depletion occurs in the vicinity of global stoichiometry for flames of any Z{sub st} and that the presence of appreciable O{sub 2} at the location of maximum temperature for high Z{sub st} flames is caused by a shift in the location of maximum temperature relative to the location of O{sub 2} depletion. This shifting is attributed to: (1) finite-rate multi-step chemistry resulting in exothermic heat release that is displaced from the location of O{sub 2} depletion and (2) the relative location of the heat release region with respect to the fuel and oxidizer boundaries in mixture fraction space. A method of superposition involving a variation of the flame sheet approximation with two heat sources is shown to be sufficient in explaining this phenomenon. (author)

Skeen, S.A.; Axelbaum, R.L. [Department of Energy, Environmental, and Chemical Engineering, Washington University in St. Louis, One Brookings Drive, Box 1180, St. Louis, MO 63130 (United States); Yablonsky, G. [Department of Energy, Environmental, and Chemical Engineering, Washington University in St. Louis, One Brookings Drive, Box 1180, St. Louis, MO 63130 (United States); Parks College, Saint Louis University, St. Louis, MO 63103 (United States)

2009-11-15

339

Results from study of potential early commercial MHD power plants and from recent ETF design work. [Engineering Test Facility  

NASA Technical Reports Server (NTRS)

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.

Hals, F.; Kessler, R.; Swallom, D.; Westra, L.; Zar, J.; Morgan, W.; Bozzuto, C.

1980-01-01

340

Fluids and Combustion Facility: Combustion Integrated Rack Modal Model Correlation  

NASA Technical Reports Server (NTRS)

The Fluids and Combustion Facility (FCF) is a modular, multi-user, two-rack facility dedicated to combustion and fluids science in the US Laboratory Destiny on the International Space Station. FCF is a permanent facility that is capable of accommodating up to ten combustion and fluid science investigations per year. FCF research in combustion and fluid science supports NASA's Exploration of Space Initiative for on-orbit fire suppression, fire safety, and space system fluids management. The Combustion Integrated Rack (CIR) is one of two racks in the FCF. The CIR major structural elements include the International Standard Payload Rack (ISPR), Experiment Assembly (optics bench and combustion chamber), Air Thermal Control Unit (ATCU), Rack Door, and Lower Structure Assembly (Input/Output Processor and Electrical Power Control Unit). The load path through the rack structure is outlined. The CIR modal survey was conducted to validate the load path predicted by the CIR finite element model (FEM). The modal survey is done by experimentally measuring the CIR frequencies and mode shapes. The CIR model was test correlated by updating the model to represent the test mode shapes. The correlated CIR model delivery is required by NASA JSC at Launch-10.5 months. The test correlated CIR flight FEM is analytically integrated into the Shuttle for a coupled loads analysis of the launch configuration. The analysis frequency range of interest is 0-50 Hz. A coupled loads analysis is the analytical integration of the Shuttle with its cargo element, the Mini Payload Logistics Module (MPLM), in the Shuttle cargo bay. For each Shuttle launch configuration, a verification coupled loads analysis is performed to determine the loads in the cargo bay as part of the structural certification process.

McNelis, Mark E.; Suarez, Vicente J.; Sullivan, Timothy L.; Otten, Kim D.; Akers, James C.

2005-01-01

341

Catalytic combustion of residual fuels  

NASA Technical Reports Server (NTRS)

A noble metal catalytic reactor was tested using two grades of petroleum derived residual fuels at specified inlet air temperatures, pressures, and reference velocities. Combustion efficiencies greater than 99.5 percent were obtained. Steady state operation of the catalytic reactor required inlet air temperatures of at least 800 K. At lower inlet air temperatures, upstream burning in the premixing zone occurred which was probably caused by fuel deposition and accumulation on the premixing zone walls. Increasing the inlet air temperature prevented this occurrence. Both residual fuels contained about 0.5 percent nitrogen by weight. NO sub x emissions ranged from 50 to 110 ppm by volume at 15 percent excess O2. Conversion of fuel-bound nitrogen to NO sub x ranged from 25 to 50 percent.

Bulzan, D. L.; Tacina, R. R.

1981-01-01

342

Combustion Fundamentals Research  

NASA Technical Reports Server (NTRS)

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.

1983-01-01

343

Combustion instability modeling and analysis  

SciTech Connect

It is well known that the two key elements for achieving low emissions and high performance in a gas turbine combustor are to simultaneously establish (1) a lean combustion zone for maintaining low NO{sub x} emissions and (2) rapid mixing for good ignition and flame stability. However, these requirements, when coupled with the short combustor lengths used to limit the residence time for NO formation typical of advanced gas turbine combustors, can lead to problems regarding unburned hydrocarbons (UHC) and carbon monoxide (CO) emissions, as well as the occurrence of combustion instabilities. The concurrent development of suitable analytical and numerical models that are validated with experimental studies is important for achieving this objective. A major benefit of the present research will be to provide for the first time an experimentally verified model of emissions and performance of gas turbine combustors. The present study represents a coordinated effort between industry, government and academia to investigate gas turbine combustion dynamics. Specific study areas include development of advanced diagnostics, definition of controlling phenomena, advancement of analytical and numerical modeling capabilities, and assessment of the current status of our ability to apply these tools to practical gas turbine combustors. The present work involves four tasks which address, respectively, (1) the development of a fiber-optic probe for fuel-air ratio measurements, (2) the study of combustion instability using laser-based diagnostics in a high pressure, high temperature flow reactor, (3) the development of analytical and numerical modeling capabilities for describing combustion instability which will be validated against experimental data, and (4) the preparation of a literature survey and establishment of a data base on practical experience with combustion instability.

Santoro, R.J.; Yang, V.; Santavicca, D.A. [Pennsylvania State Univ., University Park, PA (United States); Sheppard, E.J. [Tuskeggee Univ., Tuskegee, AL (United States). Dept. of Aerospace Engineering

1995-12-31

344

Active Combustion Control for Aircraft Gas Turbine Engines  

NASA Technical Reports Server (NTRS)

Lean-burning combustors are susceptible to combustion instabilities. Additionally, due to non-uniformities in the fuel-air mixing and in the combustion process, there typically exist hot areas in the combustor exit plane. These hot areas limit the operating temperature at the turbine inlet and thus constrain performance and efficiency. Finally, it is necessary to optimize the fuel-air ratio and flame temperature throughout the combustor to minimize the production of pollutants. In recent years, there has been considerable activity addressing Active Combustion Control. NASA Glenn Research Center's Active Combustion Control Technology effort aims to demonstrate active control in a realistic environment relevant to aircraft engines. Analysis and experiments are tied to aircraft gas turbine combustors. Considerable progress has been shown in demonstrating technologies for Combustion Instability Control, Pattern Factor Control, and Emissions Minimizing Control. Future plans are to advance the maturity of active combustion control technology to eventual demonstration in an engine environment.

DeLaat, John C.; Breisacher, Kevin J.; Saus, Joseph R.; Paxson, Daniel E.

2000-01-01

345

Study of streamwise vorticity-stirred combustion  

SciTech Connect

Experiments were conducted to establish the effects of the introduction of streamwise vorticity in combusting flows modeling those developed within small gas turbine engines. The objective of the effort was to determine whether this combustion concept has the potential for improving the volumetric heat release rates that characterize these engines. Water flow-visualization tests were performed to evolve lobed mixer configurations that, while generating vortex arrays within both the primary and secondary streams, would also provide rapid intermixing between the streams. These experiments resulted in the definition of enhanced-mixing configurations that were characterized, according to air bubble and dye trajectories, by strong interactions between the two streams. These interactions induced a substantial vertical interchange of primary and secondary fluids. Intermingling of the two fluids occurred throughout a region covering 80 percent of the height of the duct within distances from the lobe mixer trailing edge ranging from approximately one-half to one duct height. Combustion experiments were carried out in a high-pressure (7 atm) combustion apparatus using lobe-mixer combinations that exhibited the ability to induce rapid interchange between the primary and secondary streams. Direct observation and gas sampling were employed to characterize the fuel-air ratio distribution effected by the mixers. Flame geometries were compared with those developed during shear-layer combustion occurring downstream from a conventional splitter plate. The results show that the lobed mixers induce a rapid relocation of the fuel-air mixture entering the combustion test section. As contrasted with the 5- to 7-degree flame front angles that occurred during shear layer combustion, the flame front angles developed during combustion using the lobed mixers were more than twice as great, attaining levels approaching 20 degrees.

Peschke, W.T.; Mcvey, J.B.

1993-12-01

346

A laboratory scale supersonic combustive flow system  

SciTech Connect

A laboratory scale supersonic flow system [Combustive Flow System (CFS)] which utilizes the gaseous products of methane-air and/or liquid fuel-air combustion has been assembled to provide a propulsion type exhaust flow field for various applications. Such applications include providing a testbed for the study of planar two-dimensional nozzle flow fields with chemistry, three-dimensional flow field mixing near the exit of rectangular nozzles, benchmarking the predictive capability of various computational fluid dynamic codes, and the development and testing of advanced diagnostic techniques. This paper will provide a detailed description of the flow system and data related to its operation.

Sams, E.C.; Zerkle, D.K.; Fry, H.A.; Wantuck, P.J.

1995-02-01

347

Constant-Pressure Combustion Charts Including Effects of Diluent Addition  

NASA Technical Reports Server (NTRS)

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.

Turner, L Richard; Bogart, Donald

1949-01-01

348

Granular bed air heater  

Microsoft Academic Search

An apparatus and process for the transfer of heat from a hot exhaust fluid stream as, for example, produced by a combustion process, into an incoming air stream, to heat the incoming air stream close to the temperature of the exhaust stream. Such high heat transfer efficiency has heretofore not been practiced due to the fact that these exhaust streams

1982-01-01

349

Combustion intensity and distribution relation to noise generation  

NASA Technical Reports Server (NTRS)

Experiments with several different flame holder geometries were conducted to investigate the degree to which combustion roughness can be altered by altering the flame intensity and flame distribution in a ducted combustion system. The effect of admitting primary air through a plane-slotted or a slotted-swirl vane flame holder was compared and the combustion roughness and noise was contrasted with that obtained with a closed front-end perforated can. The slotted front-end burners produced much smoother burning and less noise than the closed front-end can. No advantage was apparent with swirl vs nonswirl when approximately the same inlet flow distribution was maintained. Preheated inlet air provided somewhat smoother combustion as compared with ambient temperature air. The combustion roughness with methyl alcohol was briefly compared with that of isooctane; indications are that it burns more smoothly, but more detailed studies are needed to substantiate these indications.

Plett, E. G.; Leshner, M. D.; Summerfield, M.

1975-01-01

350

Investigation of Transient Combustion Characteristics in a Single Tubular Combustor  

NASA Technical Reports Server (NTRS)

An investigation was conducted to determine the combustion response to rapid fuel-flow changes in a single tubular combustor at two simulated altitude-rotor speed conditions of 25,000 feet-70 percent rated engine speed and 50,000 feet-70 percent rated engine speed. Limiting rates of change of fuel flow (acceleration limits) were determined and the effects of certain combustion air flow variables on the transient combustion characteristics were studied with the aid of rapid-response instrumentation.

Donlon, Richard H; Mccafferty, Richard J; Straight, David M

1954-01-01

351

A combustion setup to precisely reference ?13C and ?2H isotope ratios of pure CH4 to produce isotope reference gases of ?13C-CH4 in synthetic air  

NASA Astrophysics Data System (ADS)

Isotope records of atmospheric CH4 can be used to infer changes in the biochemistry of CH4. One factor limiting quantitative estimates of changes in the biogeochemistry of CH4 are the uncertainties of the isotope measurements due to the lack of a unique isotope reference gas, certified for ?13C-CH4 or ?2H-CH4. We present a method to produce isotope reference gases for CH4 in synthetic airs that are precisely anchored to the VPDB and VSMOW scale and contain ?13C-CH4 values typical for the modern and glacial atmosphere. We quantitatively combusted two pure CH4 gases from fossil and biogenic sources and determined the ?13C and ?2H values of the produced CO2 and H2O relative to the VPDB and VSMOW scale within a very small analytical uncertainty of 0.04‰ and 0.7‰, respectively. We found isotope ratios of -39.56‰ and -56.37‰ for ?13C and -170.1‰ and -317.4‰ for ?2H in the fossil and biogenic CH4, respectively. We used both CH4 types as parental gases from which we mixed two filial CH4 gases. Their ?13C was determined to be -42.21‰ and -47.25‰, representing glacial and present atmospheric ?13C-CH4. The ?2H isotope ratios of the filial CH4 gases were found with -193.1‰ and -237.1‰, respectively. Next, we mixed aliquots of the filial CH4 gases with ultrapure N2/O2 (CH4 ≤ 2 ppb) producing two isotope reference gases of synthetic air with CH4 mixing ratios near atmospheric values. We show that our method is reproducible and does not introduce isotopic fractionation for ?13C within the uncertainties of our detection limit (we cannot conclude this for ?2H because our system is currently not prepared for ?2H-CH4 measurements in air samples). The general principle of our method can be applied to produce synthetic isotope reference gases targeting ?2H-CH4 or other gas species.

Sperlich, P.; Guillevic, M.; Buizert, C.; Jenk, T. M.; Sapart, C. J.; Schaefer, H.; Blunier, T.

2012-05-01

352

Large-scale coherent structures as drivers of combustion instability  

SciTech Connect

The role of flow coherent structures as drivers of combustion instabilities in a dump combustor was studied. Results of nonreacting tests in air and water flows as well as combustion experiments in a diffusion flame and dump combustor are discussed to provide insight into the generation process of large-scale structures in the combustor flow and their interaction with the combustion process. It is shown that the flow structures, or vortices, are formed by interaction between the flow instabilities and the chamber acoustic resonance. When these vortices dominate the reacting flow, the combustion is confined to their cores, leading to periodic heat release, which may result in the driving of high amplitude pressure oscillations. These oscillations are typical to the occurrence of combustion instabilities for certain operating conditions. The basic understanding of the interaction between flow dynamics and the combustion process opens up the possibility for rational control of combustion-induced pressure oscillations. 42 references.

Schadow, K.C.; Gutmark, E.; Parr, T.P.; Parr, D.M.; Wilson, K.J.

1987-06-01

353

Relationship between pulmonary function and indoor air pollution from coal combustion among adult residents in an inner-city area of southwest China.  

PubMed

Few studies evaluate the amount of particulate matter less than 2.5 mm in diameter (PM2.5) in relation to a change in lung function among adults in a population. The aim of this study was to assess the association of coal as a domestic energy source to pulmonary function in an adult population in inner-city areas of Zunyi city in China where coal use is common. In a cross-sectional study of 104 households, pulmonary function measurements were assessed and compared in 110 coal users and 121 non-coal users (?18 years old) who were all nonsmokers. Several sociodemographic factors were assessed by questionnaire, and ventilatory function measurements including forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), the FEV1/FVC ratio, and peak expiratory flow rate (PEFR) were compared between the 2 groups. The amount of PM2.5 was also measured in all residences. There was a significant increase in the relative concentration of PM2.5 in the indoor kitchens and living rooms of the coal-exposed group compared to the non-coal-exposed group. In multivariate analysis, current exposure to coal smoke was associated with a 31.7% decrease in FVC, a 42.0% decrease in FEV1, a 7.46% decrease in the FEV1/FVC ratio, and a 23.1% decrease in PEFR in adult residents. The slope of lung function decrease for Chinese adults is approximately a 2-L decrease in FVC, a 3-L decrease in FEV1, and an 8 L/s decrease in PEFR per count per minute of PM2.5 exposure. These results demonstrate the harmful effects of indoor air pollution from coal smoke on the lung function of adult residents and emphasize the need for public health efforts to decrease exposure to coal smoke. PMID:25296361

Jie, Y; Houjin, H; Xun, M; Kebin, L; Xuesong, Y; Jie, X

2014-11-01

354

Modeling the internal combustion engine  

NASA Technical Reports Server (NTRS)

A flexible and computationally economical model of the internal combustion engine was developed for use on large digital computer systems. It is based on a system of ordinary differential equations for cylinder-averaged properties. The computer program is capable of multicycle calculations, with some parameters varying from cycle to cycle, and has restart capabilities. It can accommodate a broad spectrum of reactants, permits changes in physical properties, and offers a wide selection of alternative modeling functions without any reprogramming. It readily adapts to the amount of information available in a particular case because the model is in fact a hierarchy of five models. The models range from a simple model requiring only thermodynamic properties to a complex model demanding full combustion kinetics, transport properties, and poppet valve flow characteristics. Among its many features the model includes heat transfer, valve timing, supercharging, motoring, finite burning rates, cycle-to-cycle variations in air-fuel ratio, humid air, residual and recirculated exhaust gas, and full combustion kinetics.

Zeleznik, F. J.; Mcbride, B. J.

1985-01-01

355

Stoichiometric Experiments with Alkane Combustion: A Classroom Demonstration  

ERIC Educational Resources Information Center

A simple, effective demonstration of the concept of limiting and excess reagent is presented. Mixtures of either air/methane (from a gas line) or air/butane (from a disposable cigarette lighter) contained in a plastic 2 L soda bottles are ignited. The mixtures combust readily when air/fuel ratios are stoichiometric, but not at a 2-fold excess of…

Zhilin, Denis M.

2012-01-01

356

Internal combustion engine  

SciTech Connect

An internal combustion engine is disclosed which comprises a plurality of cylinders split into first and second groups, the first group of cylinders held in operation independently of engine load conditions, the second group of cylinders having no supply of fuel and fresh air so as to be placed out of operation when the engine is under low load conditions, an exhaust passage connected to the exhaust ports of the first and second groups of cylinders, a sensor provided within the exhaust passage for detecting the oxygen concentration of the exhaust gases passing through the exhaust passage, control means responsive to an output of the sensor for controlling the air/fuel ratio of a mixture produced in each cylinder to an optimum value, an exahust gas purifier provided in the exhaust passage for purifying the exhaust gases passing through the exhaust passage, an exhaust gas recirculation passage having its one end connected to the intake passage of the second group of cylinders and the other end connected to the exhaust passage in arrear of the exhaust gas purifier, and valve means provided in the egr passage which is open to allow recirculation of exhaust gases through the egr passage when the engine is under low load conditions.

Iizuka, H.; Sugasawa, F.

1980-11-04

357

Synthetic and Jet Fuels Pyrolysis for Cooling and Combustion Applications.  

E-print Network

of supersonic combustion ramjet (SCRamjet) [1]. For such high velocity, the total temperature of external air combustion chamber and at proposing some parameters to enable the control of such a complex technology, considering the flow velocity, can reach 1650 K at Mach 6 and 4950 K at Mach 12. This produces a dramatic

Boyer, Edmond

358

Coal combustion and its pollution control in China  

Microsoft Academic Search

Coal combustion will continue to be a major component of energy production in the foreseeable future, owing to its abundance in China. A primary challenge will be to seek ways to utilize the coal resources in an environmentally acceptable manner. This paper presents the coal combustion scenario and its related air pollution in China. Some commonly used technologies for removing

C. F. You; X. C. Xu

2010-01-01

359

40 CFR 60.3062 - What is an air curtain incinerator?  

Code of Federal Regulations, 2011 CFR

...integrated combustion chamber (fire box) or open pit or trench (trench burner) in which combustion occurs. For the purpose...only, air curtain incinerators include both firebox and trench burner units. (b) Air curtain incinerators...

2011-07-01

360

40 CFR 60.2970 - What is an air curtain incinerator?  

Code of Federal Regulations, 2010 CFR

...integrated combustion chamber (fire box) or open pit or trench (trench burner) in which combustion occurs. For the purpose...only, air curtain incinerators include both firebox and trench burner units. (b) Air curtain incinerators...

2010-07-01

361

40 CFR 60.3062 - What is an air curtain incinerator?  

Code of Federal Regulations, 2010 CFR

...integrated combustion chamber (fire box) or open pit or trench (trench burner) in which combustion occurs. For the purpose...only, air curtain incinerators include both firebox and trench burner units. (b) Air curtain incinerators...

2010-07-01

362

40 CFR 60.2970 - What is an air curtain incinerator?  

Code of Federal Regulations, 2011 CFR

...integrated combustion chamber (fire box) or open pit or trench (trench burner) in which combustion occurs. For the purpose...only, air curtain incinerators include both firebox and trench burner units. (b) Air curtain incinerators...

2011-07-01

363

In-line air filter apparatus  

SciTech Connect

This patent describes an internal combustion engine disposed within an engine compartment of a motor vehicle. This paper describes improvement in an in-line air filter apparatus for providing filtered air having reduced pressure drop across the filter and reduced turbulence to the engine air intake hose of the internal combustion engine. It comprises an ambient air intake disposed at the front of and within the engine compartment of the motor vehicle having the internal combustion engine; an air filter housing having an ambient air intake end at a front end thereof, attached to the ambient air intake and disposed within the engine compartment of the motor vehicle and a filtered air outlet end of the opposite, rear end thereof, and a medial housing portion disposed therebetween; a tubular air filter element longitudinally disposed and enclosed within the air filter housing from passage of ambient air to be filtered therethrough.

Stanhope, K.C.; Simms, P.E.

1992-06-30

364

Low NOx combustion system for heavy oil  

SciTech Connect

As a result of the increasing demand for white oil as one of countermeasures for pollution control and as a fuel for motor vehicle, coupled with the increasing import of heavy crude oil, heavy oils such as asphalt and distillation residue have become surplus in Japan. It is difficult by the conventional low NOx technology to control the NOx emission from the industrial small and medium capacity boilers, which use heavy oil as their fuels. The authors have been developing and improving NOx control technologies for boilers such as low NOx burners, two-stage combustion methods and so on. They have developed a new combustion system for heavy oil, which generates less NOx and soot than conventional systems, by applying the knowledge, obtained in the course of their development of Coal Partial Combustor (CPC). The conventional low NOx combustion method for oil firing boilers has been developed based on decreasing the flame temperature and delaying the combustion reaction. In the system, however, the heavy oil shall be combusted in the intense reducing atmosphere at the high flame temperature between 1,500 C and 1,600 C, and then the combustions gas shall be cooled and oxidized by two-stage combustion air. With this system, NOx emission can be suppressed below 100ppm (converted as O{sub 2}=4%).

Kurata, Chikatoshi; Sasaki, Hideki

1999-07-01

365

Coal-water slurry fuel internal combustion engine and method for operating same  

DOEpatents

An internal combustion engine fueled with a coal-water slurry is described. About 90 percent of the coal-water slurry charge utilized in the power cycle of the engine is directly injected into the main combustion chamber where it is ignited by a hot stream of combustion gases discharged from a pilot combustion chamber of a size less than about 10 percent of the total clearance volume of main combustion chamber with the piston at top dead center. The stream of hot combustion gases is provided by injecting less than about 10 percent of the total coal-water slurry charge into the pilot combustion chamber and using a portion of the air from the main combustion chamber that has been heated by the walls defining the pilot combustion chamber as the ignition source for the coal-water slurry injected into the pilot combustion chamber.

McMillian, Michael H. (Fairmont, WV)

1992-01-01

366

Oil shale retorting and combustion system  

DOEpatents

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.

Pitrolo, Augustine A. (Fairmont, WV); Mei, Joseph S. (Morgantown, WV); Shang, Jerry Y. (Fairfax, VA)

1983-01-01

367

Combustion Technology Development for an Advanced Glass Melting System  

E-print Network

Concept feasibility of an innovative technology for glass production has recently been demonstrated. It is based on suspension heating of the glass-forming batch minerals while entrained in a combustion flow of preheated air and natural gas...

Stickler, D. B.; Westra, L.; Woodroffe, J.; Jeong, K. M.; Donaldson, L. W.

368

The combustion process  

NASA Technical Reports Server (NTRS)

The effect of thermodynamic, chemical, and physical properties on the combustion of materials is discussed. The mechanisms which produce and support combustion of various materials are examined. The effects of free radical reactions, convection and gravitational effects on combustion rates, and changes in flame propagation due to size and shape of surfaces are described.

Downs, W. R.

1971-01-01

369

Combustion synthesis and nanomaterials  

Microsoft Academic Search

The recent developments and trends in combustion science towards the synthesis of nanomaterials are discussed. Different modifications made to conventional combustion approaches for preparation of nanomaterials are critically analyzed. Special attention is paid to various applications of combustion synthesized nanosized products.

Singanahally T. Aruna; Alexander S. Mukasyan

2008-01-01

370

Controlling dioxins from municipal waste combustion  

SciTech Connect

Improved combustion practices and air pollution control research within the past decade have made MWCs a minor- and diminishing -source of dioxins in the environment. This article describes air pollution controls which have reduced the amount of dioxin releases. Topics include: dioxin and furan formation; controlling dioxin emissions; effective control in units with scrubber/baghouses; reducing APC system temperatures; effectiveness of activated carbon injection; reductions at existing facilities with ESPs; will reducing the feed chlorine work?. 35 refs., 5 figs.

Hasselriis, F.

1995-07-01

371

Catalytic Unmixed Combustion of Coal with Zero Pollution  

Microsoft Academic Search

GE Global Research is developing an innovative energy-based technology for coal combustion with high efficiency and near-zero pollution. This Unmixed Combustion of coal (UMC-Coal) technology simultaneously converts coal, steam and air into two separate streams of high pressure COâ-rich gas for sequestration, and high-temperature, high-pressure vitiated air for producing electricity in gas turbine expanders. The UMC process utilizes an oxygen

George Rizeq; Parag Kulkarni; Raul Subia; Wei Wei

2005-01-01

372

Pilot scale combustion evaluation of waste and alternate fuels, phase 3  

Microsoft Academic Search

The results of three studies which evaluated the combustion of waste products and alternate fuels are presented. The first evaluated a distributed air staging concept for NOx control in pulverized coal fired systems. The second evaluated combustion control techniques and NO emissions when firing coal\\/oil mixtures. The third evaluated emissions and combustion characteristics of refuse derived fuel (RDF) cofired with

R. A. Brown; C. F. Busch

1980-01-01

373

Millwright Apprenticeship. Related Training Modules. 10.1-10.5 Combustion.  

ERIC Educational Resources Information Center

This packet, part of the instructional materials for the Oregon apprenticeship program for millwright training, contains five modules covering combustion. The modules provide information on the following topics: the combustion process, types of fuel, air and fuel gases, heat transfer, and combustion in wood. Each module consists of a goal,…

Lane Community Coll., Eugene, OR.

374

Wick-type liquid-metal combustion. Annual report, 15 October 1988-14 October 1989  

Microsoft Academic Search

An experimental and theoretical investigation was conducted to study the wick combustion of lithium and sulfur hexafluoride. A single-line laser induced fluorescence thermometry with Li2 as fluorescence species was developed. The calibration experiments yielded promising results; refinements, however, are needed before the technique can be applied to combustion flame measurements. Wick combustion of ethanol and hexane in air as well

L. D. Chen; H. Y. Lyu; K. Y. Hsu

1989-01-01

375

AN OVERVIEW OF EPA'S COMBUSTION RESEARCH PROGRAM  

EPA Science Inventory

The Air Pollution Technology Branch (APTB) of the U.S. Environmental Protection Agency's National Risk Management Research Laboratory, located in Research Triangle Park, North Carolina, performs a variety of combustion related research. Currently APTB's focus is on mercury from c...

376

Combustion characteristics of gas turbine alternative fuels  

NASA Technical Reports Server (NTRS)

An experimental investigation was conducted to obtain combustion performance values for specific heavyend, synthetic hydrocarbon fuels. A flame tube combustor modified to duplicate an advanced gas turbine engine combustor was used for the tests. Each fuel was tested at steady-state operating conditions over a range of mass flow rates, fuel-to-air mass ratio, and inlet air temperatures. The combustion pressure, as well as the hardware, were kept nearly constant over the program test phase. Test results were obtained in regards to geometric temperature pattern factors as a function of combustor wall temperatures, the combustion gas temperature, and the combustion emissions, both as affected by the mass flow rate and fuel-to-air ratio. The synthetic fuels were reacted in the combustor such that for most tests their performance was as good, if not better, than the baseline gasoline or diesel fuel tests. The only detrimental effects were that at high inlet air temperature conditions, fuel decomposition occurred in the fuel atomizing nozzle passages resulting in blockage. And the nitrogen oxide emissions were above EPA limits at low flow rate and high operating temperature conditions.

Rollbuhler, R. James

1987-01-01

377

Coal combustion on environment pollution in China  

Microsoft Academic Search

China is the biggest country of coal production and consumption and coal combustion is the biggest pollution for China's air pollution. The status coal production, processing and utilization, atmosphere environment pollution in China is analyzed in this paper, and discuss the way to dealing with the problem. Coal cleaning and coal briquette being the basis of the clean coal technology

Qiang Zhou; Yuegang Tang

2011-01-01

378

Global reaction schemes for hydrocarbon combustion  

Microsoft Academic Search

Global reaction schemes for the combustion of alkane hydrocarbons up to butane in mixtures with air in premixed and diffusion flames have been derived using analysis of flame structures. The schemes include two competing fuel breakdown reactions, and equilibrium assumptions have been used to derive initial estimates of the forms of the rate expressions. The deduced four-step reaction mechanism is

W. P. Jones; R. P. Lindstedt

1988-01-01

379

SOURCE ASSESSMENT: RESIDENTIAL COMBUSTION OF COAL  

EPA Science Inventory

The report summarizes the assessment of air emissions from the residential combustion of anthracite, bituminous, and lignite coals, with emphasis on bituminous coals. Approximately 2.6 million metric tons of coal were burned as a primary source of heat in an estimated 493,018 hou...

380

Modeling coal combustion behavior in an ironmaking blast furnace raceway: model development and applications  

SciTech Connect

A numerical model has been developed and validated for the investigation of coal combustion phenomena under blast furnace operating conditions. The model is fully three-dimensional, with a broad capacity to analyze significant operational and equipment design changes. The model was used in a number of studies, including: Effect of cooling gas type in coaxial lance arrangements. It was found that oxygen cooling improves coal burnout by 7% compared with natural gas cooling under conditions that have the same amount of oxygen enrichment in the hot blast. Effect of coal particle size distribution. It was found that during two similar periods of operation at Port Kembla's BF6, a difference in PCI capability could be attributed to the difference in coal size distribution. Effect of longer tuyeres. Longer tuyeres were installed at Port Kembla's BF5, leading to its reline scheduled for March 2009. The model predicted an increase in blast velocity at the tuyere nose due to the combustion of volatiles within the tuyere, with implications for tuyere pressure drop and PCI capability. Effect of lance tip geometry. A number of alternate designs were studied, with the best-performing designs promoting the dispersion of the coal particles. It was also found that the base case design promoted size segregation of the coal particles, forcing smaller coal particles to one side of the plume, leaving larger coal particles on the other side. 11 refs., 15 figs., 4 tabs.

Maldonado, D.; Austin, P.R.; Zulli, P.; Guo B. [BlueScope Steel Research Laboratories, Port Kembla, NSW (Australia)

2009-03-15

381

Oxy-Combustion Boiler Material Development  

SciTech Connect

Under U.S. Department of Energy Cooperative Agreement No. DE-NT0005262 Foster Wheeler North America Corp conducted a laboratory test program to determine the effect of oxy-combustion on boiler tube corrosion. In this program, CFD modeling was used to predict the gas compositions that will exist throughout and along the walls of air-fired and oxy-fired boilers operating with low to high sulfur coals. Test coupons of boiler tube materials were coated with deposits representative of those coals and exposed to the CFD predicted flue gases for up to 1000 hours. The tests were conducted in electric tube furnaces using oxy-combustion and air-fired flue gases synthesized from pressurized cylinders. Following exposure, the test coupons were evaluated to determine the total metal wastage experienced under air and oxy-combustions conditions and materials recommendations were made. Similar to air-fired operation, oxy-combustion corrosion rates were found to vary with the boiler material, test temperature, deposit composition, and gas composition. Despite this, comparison of air-fired and oxy-fired corrosion rates showed that oxy-firing rates were, for the most part, similar to, if not lower than those of air-firing; this finding applied to the seven furnace waterwall materials (wrought and weld overlay) and the ten superheater/reheater materials (wrought and weld overlay) that were tested. The results of the laboratory oxy-combustion tests, which are based on a maximum bulk flue gas SO{sub 2} level of 3200 ppmv (wet) / 4050 ppmv (dry), suggest that, from a corrosion standpoint, the materials used in conventional subcritical and supercritical, air-fired boilers should also be suitable for oxy-combustion retrofits. Although the laboratory test results are encouraging, they are only the first step of a material evaluation process and it is recommended that follow-on corrosion tests be conducted in coal-fired boilers operating under oxy-combustion to provide longer term (one to two year) data. The test program details and data are presented herein.

Michael Gagliano; Andrew Seltzer; Hans Agarwal; Archie Robertson; Lun Wang

2012-01-31

382

Oxy-Combustion Boiler Material Development  

SciTech Connect

Under U.S. Department of Energy Cooperative Agreement No. DE-NT0005262 Foster Wheeler North America Corp conducted a laboratory test program to determine the effect of oxy-combustion on boiler tube corrosion. In this program, CFD modeling was used to predict the gas compositions that will exist throughout and along the walls of air-fired and oxy-fired boilers operating with low to high sulfur coals. Test coupons of boiler tube materials were coated with deposits representative of those coals and exposed to the CFD predicted flue gases for up to 1000 hours. The tests were conducted in electric tube furnaces using oxy-combustion and air-fired flue gases synthesized from pressurized cylinders. Following exposure, the test coupons were evaluated to determine the total metal wastage experienced under air and oxy-combustions conditions and materials recommendations were made. Similar to air-fired operation, oxy-combustion corrosion rates were found to vary with the boiler material, test temperature, deposit composition, and gas composition. Despite this, comparison of air-fired and oxy-fired corrosion rates showed that oxy-firing rates were, for the most part, similar to, if not lower than those of air-firing; this finding applied to the seven furnace waterwall materials (wrought and weld overlay) and the ten superheater/reheater materials (wrought and weld overlay) that were tested. The results of the laboratory oxy-combustion tests, which are based on a maximum bulk flue gas SO2 level of 3200 ppmv (wet) / 4050 ppmv (dry), suggest that, from a corrosion standpoint, the materials used in conventional subcritical and supercritical, air-fired boilers should also be suitable for oxy-combustion retrofits. Although the laboratory test results are encouraging, they are only the first step of a material evaluation process and it is recommended that follow-on corrosion tests be conducted in coal-fired boilers operating under oxy-combustion to provide longer term (one to two year) data. The test program details and data are presented herein.

Gagliano, Michael; Seltzer, Andrew; Agarwal, Hans; Robertson, Archie; Wang, Lun

2012-01-31

383

Performance calculations for 1000 MWe MHD/steam power plants  

NASA Technical Reports Server (NTRS)

The effects of MHD generator operating conditions and constraints on the performance of MHD/steam power plants are investigated. Power plants using high temperature combustion air preheat (2500 F) and plants using intermediate temperature preheat (1100 F) with oxygen enrichment are considered. Variations of these two types of power plants are compared on the basis of fixed total electrical output (1000 MWe). Results are presented to show the effects of generator plant length and level of oxygen enrichment on the plant thermodynamic efficiency and on the required generator mass flow rate. Factors affecting the optimum levels of oxygen enrichment are analyzed. It is shown that oxygen enrichment can reduce magnet stored energy requirement.

Pian, C. C. P.

1981-01-01

384

Low emission U-fired boiler combustion system  

DOEpatents

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.

Ake, Terence (North Brookfield, MA); Beittel, Roderick (Worcester, MA); Lisauskas, Robert A. (Shrewsbury, MA); Reicker, Eric (Barre, MA)

2000-01-01

385

JANNAF 36th Combustion Subcommittee Meeting. Volume 1  

NASA Technical Reports Server (NTRS)

Volume 1, the first of three volumes is a compilation of 47 unclassified/unlimited-distribution technical papers presented at the Joint Army-Navy-NASA-Air Force (JANNAF) 36th Combustion Subcommittee held jointly with the 24th Airbreathing Propulsion Subcommittee and 18th Propulsion Systems Hazards Subcommittee. The meeting was held on 18-21 October 1999 at NASA Kennedy Space Center and The DoubleTree Oceanfront Hotel, Cocoa Beach, Florida. Solid phase propellant combustion topics covered in this volume include cookoff phenomena in the pre- and post-ignition phases, solid rocket motor and gun propellant combustion, aluminized composite propellant combustion, combustion modeling and combustion instability and instability measurement techniques.

Fry, Ronald S. (Editor); Gannaway, Mary T. (Editor)

1999-01-01

386

AIR POLLUTION TECHNOLOGY BRANCH (AIR POLLUTION PREVENTION AND CONTROL DIVISION, NRMRL)  

EPA Science Inventory

Fundamental and applied combustion research has been conducted by the Air Pollution Prevention and Control Division's Air Pollution Technology Branch (APTB)and its predecessors since EPA's inception. APTB has been instrumental in the development and successful application of flue...

387

NOx Emission Reduction by Oscillating Combustion  

SciTech Connect

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 efficiency 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 attributes of oscillating combustion and on the results of an earlier project at GTI and Air Liquide, to determine which applications for oscillating combustion would show the greatest probability for technical success and greatest probability for market acceptability. The market study indicated that furnaces in the steel, glass, and metal melting industries would perform well in both categories. These findings guided the selection of burners for laboratory testing and, with the results of the laboratory testing, guided the selection of field test sites.

John C. Wagner

2004-03-31

388

NOx Emission Reduction by Oscillating combustion  

SciTech Connect

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 efficiency 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 attributes of oscillating combustion and on the results of an earlier project at GTI and Air Liquide, to determine which applications for oscillating combustion would show the greatest probability for technical success and greatest probability for market acceptability. The market study indicated that furnaces in the steel, glass, and metal melting industries would perform well in both categories. These findings guided the selection of burners for laboratory testing and, with the results of the laboratory testing, guided the selection of field test sites.

Institute of Gas Technology

2004-01-30

389

Combustion of coal dust-air mixtures  

Microsoft Academic Search

Coal dust flammability studies are essential in order to evaluate propagation limit concentrations and the fundamental burning velocity as a function of dust concentration. This work presents such data for Pittsburgh seam bituminous coal dust using a relatively large scale horizontal flammability apparatus, the Gravity Tumbler Flammability Tube (GTFT). The reported lean limit (based on propagating a steady-state constant pressure

Slezak

1984-01-01

390

Staged combustion of rice straw in a fluidized bed  

SciTech Connect

Staged combustion of rice straw has been investigated using an atmospheric bubbling fluidized bed combustor. The combustor has a 300 mm ID and a 3300 mm height. Secondary air was introduced in the freeboard at 1500 mm above the primary air distributor. Rice straw was fed as cylindrical pellets of a 12 mm diameter and 10-15 mm lengths. The obtained results indicate that staged combustion appears an effective technique to reduce NO{sub x} emissions, in particular, at higher operating temperatures. Typically, at 850 C bed temperature, NO{sub x} concentration is reduced by about 50% when 30% of fed air is introduced as secondary air. Staged operation has a slight, non-monotonic effect on SO{sub 2} emission. Combustion efficiency improves with increasing secondary air ratio reaching a maximum value that is mainly attributed to a reduction in fixed carbon loss. With further increase in secondary air ratio, combustion efficiency, however, decreases again since entrained fixed carbon and exhausted carbon monoxide tend to increase. The range of secondary air ratio, over which combustion efficiency improves, expands at higher operating temperatures. (author)

Okasha, F. [Department of Mechanical Engineering, Mansoura University (Egypt)

2007-10-15

391

Rapid Deployment of Rich Catalytic Combustion  

SciTech Connect

The overall objective of this research under the Turbines Program is the deployment of fuel flexible rich catalytic combustion technology into high-pressure ratio industrial gas turbines. The resulting combustion systems will provide fuel flexibility for gas turbines to burn coal derived synthesis gas or natural gas and achieve NO{sub x} emissions of 2 ppmvd or less (at 15 percent O{sub 2}), cost effectively. This advance will signify a major step towards environmentally friendly electric power generation and coal-based energy independence for the United States. Under Phase 1 of the Program, Pratt & Whitney (P&W) performed a system integration study of rich catalytic combustion in a small high-pressure ratio industrial gas turbine with a silo combustion system that is easily scalable to a larger multi-chamber gas turbine system. An implementation plan for this technology also was studied. The principal achievement of the Phase 1 effort was the sizing of the catalytic module in a manner which allowed a single reactor (rather than multiple reactors) to be used by the combustion system, a conclusion regarding the amount of air that should be allocated to the reaction zone to achieve low emissions, definition of a combustion staging strategy to achieve low emissions, and mechanical integration of a Ceramic Matrix Composite (CMC) combustor liner with the catalytic module.

Richard S. Tuthill

2004-06-10

392

Analysis of cyclic combustion of the coal-water suspension  

NASA Astrophysics Data System (ADS)

Combustion technology of the coal-water suspension creates a number of new possibilities to organize the combustion process fulfilling contemporary requirements, e.g. in the environment protection. Therefore the in-depth analysis is necessary to examine the technical application of coal as a fuel in the form of suspension. The research undertakes the complex investigations of the continuous coal-water suspension as well as cyclic combustion. The cyclic nature of fuel combustion results from the movement of the loose material in the flow contour of the circulating fluidized bed (CFB): combustion chamber, cyclone and downcomer. The experimental results proved that the cyclic change of oxygen concentration around fuel, led to the vital change of both combustion mechanisms and combustion kinetics. The mathematical model of the process of fuel combustion has been presented. Its original concept is based on the allowance for cyclic changes of concentrations of oxygen around the fuel. It enables the prognosis for change of the surface and the centre temperatures as well as mass loss of the fuel during combustion in air, in the fluidized bed and during the cyclic combustion.

Kijo-Kleczkowska, Agnieszka

2011-04-01

393

Identification of biomass co-combustion operating point using image processing  

NASA Astrophysics Data System (ADS)

Thermal power and excess air coefficient are one of key parameters that characterize operating point of combustion process. In practice, they are hard to determine directly. The k-nearest neighbor (k-NN) regression algorithm was applied where some flame image geometric parameters were used as predictors. The model was assessed by carrying out several combustion tests for nine different settings of the laboratory combustion facility. Thermal power and excess air coefficient were kept constant and set independently for known biomass content.

Kotyra, Andrzej; Wójcik, Waldemar; Iskakova, Aigul; Zhussupbektov, Sarsenbek

2014-08-01

394

Real-time combustion controller  

DOEpatents

A method and system are disclosed for regulating the air to fuel ratio supplied to a burner to maximize the combustion efficiency. Optical means are provided in close proximity to the burner for directing a beam of radiation from hot gases produced by the burner to a plurality of detectors. Detectors are provided for sensing the concentration of, inter alia, CO, CO{sub 2}, and H{sub 2}O. The differences between the ratios of CO to CO{sub 2} and H{sub 2}O to CO are compared with a known control curve based on those ratios for air to fuel ratios ranging from 0.85 to 1.30. The fuel flow is adjusted until the difference between the ratios of CO to CO{sub 2} and H{sub 2}O to CO fall on a desired set point on the control curve. 20 figs.

Lindner, J.S.; Shepard, W.S.; Etheridge, J.A.; Jang, P.R.; Gresham, L.L.

1997-02-04

395

Real-time combustion controller  

DOEpatents

A method and system of regulating the air to fuel ratio supplied to a burner to maximize the combustion efficiency. Optical means are provided in close proximity to the burner for directing a beam of radiation from hot gases produced by the burner to a plurality of detectors. Detectors are provided for sensing the concentration of, inter alia, CO, CO.sub.2, and H.sub.2 O. The differences between the ratios of CO to CO.sub.2 and H.sub.2 O to CO are compared with a known control curve based on those ratios for air to fuel ratios ranging from 0.85 to 1.30. The fuel flow is adjusted until the difference between the ratios of CO to CO.sub.2 and H.sub.2 O to CO fall on a desired set point on the control curve.

Lindner, Jeffrey S. (Starkville, MS); Shepard, W. Steve (Starkville, MS); Etheridge, John A. (Starkville, MS); Jang, Ping-Rey (Starkville, MS); Gresham, Lawrence L. (Starkville, MS)

1997-01-01

396

Simulated Altitude Investigation of Stewart-Warner Model 906-B Combustion Heater  

NASA Technical Reports Server (NTRS)

An investigation has been conducted to determine thermal and pressure-drop performance and the operational characteristics of a Stewart-Warner model 906-B combustion heater. The performance tests covered a range of ventilating-air flows from 500 to 3185 pounds per hour, combustion-air pressure drops from 5 to 35 inches of water, and pressure altitudes from sea level to 41,000 feet. The operational characteristics investigated were the combustion-air flows for sustained combustion and for consistent ignition covering fuel-air ratios ranging from 0.033 to 0.10 and pressure altitudes from sea level to 45,000 feet. Rated heat output of 50,000 Btu per hour was obtained at pressure altitudes up to 27,000 feet for ventilating-air flows greater than 800 pounds per hour; rated output was not obtained at ventilating-air flow below 800 pounds per hour at any altitude. The maximum heater efficiency was found to be 60.7 percent at a fuel-air ratio of 0.050, a sea-level pressure altitude, a ventilating-air temperature of 0 F, combustion-air temperature of 14 F, a ventilating-air flow of 690 pounds per hour, and a combustion-air flow of 72.7 pounds per hour. The minimum combustion-air flow for sustained combustion at a pressure altitude of 25,000 feet was about 9 pounds per hour for fuel-air ratios between 0.037 and 0.099 and at a pressure altitude of 45,000 feet increased to 18 pounds per hour at a fuel-air ratio of 0.099 and 55 pounds per hour at a fuel-air ratio of 0.036. Combustion could be sustained at combustion-air flows above values of practical interest. The maximum flow was limited, however, by excessively high exhaust-gas temperature or high pressure drop. Both maximum and minimum combustion-air flows for consistent ignition decrease with increasing pressure altitude and the two curves intersect at a pressure altitude of approximately 25,000 feet and a combustion-air flow of approximately 28 pounds per hour.

Ebersbach, Frederick R.; Cervenka, Adolph J.

1947-01-01

397

Integration of air separation membrane and coalescing filter for use on an inlet air system of an engine  

SciTech Connect

An intake air separation system suitable for combustion air of an internal combustion engine. An air separation device of the system includes a plurality of fibers, each fiber having a tube with a permeation barrier layer on the outer surface thereof and a coalescing layer on the inner surface thereof, to restrict fluid droplets from contacting the permeation barrier layer.

Moncelle, Michael E. (Bloomington, IL)

2003-01-01

398

Tripropellant combustion process  

NASA Technical Reports Server (NTRS)

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.

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

1988-01-01

399

Liquid fuel combustion within silicon-carbide coated carbon foam  

SciTech Connect

Combustion of kerosene inside porous inert medium (PIM) has been investigated with the goal of reducing the emissions of nitric oxides (NO{sub x}), carbon monoxide (CO) and soot. Silicon-carbide (SiC) coated carbon foam is used as PIM to attain high structural strength. The two-zone porous burner design consists of preheat and combustion sections. Different PIM configurations were tested by stacking together square porous pieces of 2.5 cm thickness. Two types of fuel injectors are considered: (i) in the air-assist injector, approximately 5% of the combustion air is used for atomization and the remaining air enters as the primary co-flow around the injector, and (ii) in the swirling-air injector, all of the combustion air enters the injector to create a swirling flow around the fuel jet to enhance atomization and fuel-air premixing. The distance between the injector and PIM inlet is a key operational parameter, which was varied in experiments with both injectors over a range of equivalence ratios and heat release rates. The NO{sub x} and CO emissions were measured to optimize the PIM configuration with minimum emissions. Results show stable combustion over a wide operating range. Three combustor operational regimes are identified depending upon the injector location. (author)

Vijaykant, S.; Agrawal, Ajay K. [Department of Mechanical Engineering, University of Alabama, Tuscaloosa, AL 35487 (United States)

2007-10-15

400

Considerations on Mixing and Combustion of a Scramjet Engine  

NASA Astrophysics Data System (ADS)

The main purpose of this study is to reveal a transition mechanism between two typical combustion modes called ‘weak-combustion’ and ‘intensive-combustion’ observed in the firing tests of scramjet engines at Mach 4, 6 and 8 conditions of Ramjet Engine Test Facility (RJTF). For this purpose, flow structures in the combustor and their changes during the transition of the combustion mode are investigated by cold flow tests as well as numerical simulations. These results and the firing test results led us to conclude 1) that transition from ‘weak mode’ to ‘intensive mode’ is the consequence of the mutual interaction between enhancement of fuel/air mixing as well as combustion within the boundary layer and the growth of the boundary layer separation area and 2) that in the present engine principal fuel/air mixing and combustion strongly depend on the occurrence of large-scale boundary layer separation, thus the resulting principal combustion is characterized to be subsonic combustion within the separated boundary layer.

Sunami, Tetsuji; Kodera, Masatoshi; Nakahashi, Kazuhiro

401

Exhaust gas recirculation system for internal combustion engine  

Microsoft Academic Search

An internal combustion engine is provided with an exhaust gas recirculating passage for communicating the intake passage and the exhaust passage thereof. The recirculating passage is provided with a valve for controlling the amount of recirculated exhaust gas. A fundamental air-fuel ratio control value for regulating the air-fuel ratio of the intake gas to a predetermined value is corrected by

S. Yoshioka; Y. Nomoto; T. Oda; K. Yokooku

1984-01-01

402

Exhaust gas recirculation system for an internal combustion engine  

Microsoft Academic Search

In an internal combustion engine having an intake passage provided therein with a throttle valve for controlling intake flow of air or an air-fuel mixture passing therethrough toward engine cylinders and an exhaust passage, an exhaust gas recirculation system comprises first means for conducting a portion of the exhaust gases from the exhaust passage into the intake passage downstream of

Higashi

1984-01-01

403

Lithium combustion: A review. Final report, Feb-Jun 90  

SciTech Connect

This review deals with the chemical reactions, ignition, and combustion of lithium in air and in the components of air, including oxygen, nitrogen, water, and carbon dioxide. It was found that lithium reacts vigorously with these substances. In addition, a review of extinguishing lithium fires is included. Of the extinguishing agents, carbon has been found to be the most effective.

Rhein, R.A.

1990-12-01

404

TOXIC SUBSTANCES FROM COAL COMBUSTION-A COMPREHENSIVE ASSESSMENT  

Microsoft Academic Search

The Clean Air Act Amendments of 1990 identify a number of hazardous air pollutants (HAPs) as candidates for regulation. Should regulations be imposed on HAP emissions from coal-fired power plants, a sound understanding of the fundamental principles controlling the formation and partitioning of toxic species during coal combustion will be needed. With support from the National Energy Technology Laboratory (NETL),

C. L. Senior; F. Huggins; G. P. Huffman; N. Shah; N. Yap; J. O. L. Wendt; W. Seames; M. R. Ames; A. F. Sarofim; S. Swenson; J. S. Lighty; A. Kolker; R. Finkelman; C. A. Palmer; S. J. Mroczkowski; J. J. Helble; R. Mamani-Paco; R. Sterling; G. Dunham; S. Miller

2001-01-01

405

Subsonic and supersonic combustion using noncircular injectors  

NASA Astrophysics Data System (ADS)

Nonreacting and combustion tests were performed for subsonic, sonic, and supersonic conditions using noncircular injectors in a gas generator combustor. The noncircular injectors, including square, equilateral-, and isosceles-triangular nozzles, were compared to a circular injector. The flowfields of the jets were mapped with hot-wire anemometry and visualized using spark schlieren photography. The combustion characteristics were visualized by high-speed photography and thermal imaging, and the temperature distribution was measured by a rake of thermocouples. The present tests conducted at high Reynolds and Mach numbers confirmed earlier results obtained for the low range of these numbers, i.e., the combination of large-scale mixing at the flat sides with the fine-scale mixing at the vertices is benefical for combustion. Large-scale structures provide bulk mixing between the fuel and air, whereas fine-scale mixing contributes to the reaction rate and to better flameholding characteristics.

Gutmark, E.; Schadow, K. C.; Wilson, K. J.

1991-04-01

406

ASRM combustion instability studies  

NASA Technical Reports Server (NTRS)

The objectives of this task were to measure and compare the combustion response characteristics of the selected propellant formulation for the Space Shuttle Advanced Solid Rocket Motor (ASRM) with those of the current Redesigned Solid Rocket Motor (RSRM) formulation. Tests were also carried out to characterize the combustion response of the selected propellant formulation for the ASRM igniter motor.

Strand, L. D.

1992-01-01

407

Fifteenth combustion research conference  

SciTech Connect

The BES research efforts cover chemical reaction theory, experimental dynamics and spectroscopy, thermodynamics of combustion intermediates, chemical kinetics, reaction mechanisms, combustion diagnostics, and fluid dynamics and chemically reacting flows. 98 papers and abstracts are included. Separate abstracts were prepared for the papers.

NONE

1993-06-01

408

Apparatus and technique for supercharging combustion engines  

SciTech Connect

A method of compressing the air supply to the carburetion system of a variable speed engine operated by the combustion of an air fuel mixture therein is described comprising: interconnecting the discharge outlet of a single stage, high speed centrifugal air compressor with the carburetion system of the engine, interconnecting the power output shaft of a variable speed electric motor with the impeller of the compressor through a differential transmission, the compressor having an inlet which opens into ambient atmosphere of the compressor for the intake of air therefrom, electrically activating the motor to drive the impeller and deliver compressed air to the carburetion system of the engine, the motor and the transmission being adapted to rotate the impeller within a range of 30,000 revolutions per minute or greater, and the speed of the motor being controlled so as to vary the speed of the impeller within the aforesaid range, commensurate with the speed of the engine.

Cook, G.F.

1988-02-16

409

Properties of air and combustion products of fuels with air  

NASA Technical Reports Server (NTRS)

Thermodynamic and transport properties include ratio of specific heats, molecular weight, viscosity, heat capacity, thermal conductivity, and Prandtl number. Properties are calculated from 300 to 2500 degrees K and for pressures of three and ten atmospheres.

Lewandowski, K.; Poferl, D. J.; Svevla, R.

1969-01-01

410

Combustion Enhancement Using a Silent Discharge Plasma Reactor  

NASA Astrophysics Data System (ADS)

Electric fields affect flame propagation speed, stability, and combustion chemistry. External electrodes, arc discharges, and plasma jets have been used to combust gas mixtures outside their flammability limits. Experiments with silent electrical discharges (SEDs) and propagating flames have shown that flame propagation velocity is actually decreased (combustion retarded) when an SED is applied directly to the flame region, but velocity is increased (combustion promoted) when applied to the unburned gas mixture upstream of a flame. More recent work has proposed electric arc/microwave-driven plasma-generating fuel nozzles to produce dissociated fuel or ionized fuel for aircraft gas turbine engine combustor mixers. In contrast to prior works, we have used a silent discharge plasma (SDP) reactor to break up large fuel molecules into smaller molecules and create free radicals/active species in a gas stream before the fuel is mixed with an oxidizer and combusted. A cylindrical SDP reactor was used to 'activate' propane before mixing it with air and igniting the combustible gas mixture. With the plasma, the physical appearance of the flame changes and substantial changes in mass spectrometer fragmentation peaks for fuel and combustion products are observed (i.e., combustion is enhanced). Results of changes in the degree of combustion will be discussed in terms of variations in the plasma specific energy.

Rosocha, Louis; Platts, David; Coates, Don; Stange, Sy

2003-10-01

411

Effects of inlet distortion on gas turbine combustion chamber exit temperature profiles  

NASA Astrophysics Data System (ADS)

Damage to a nozzle guide vane or blade, caused by non-uniform temperature distributions at the combustion chamber exit, is deleterious to turbine performance and can lead to expensive and time consuming overhaul and repair. A test rig was designed and constructed for the Allison 250-C20B combustion chamber to investigate the effects of inlet air distortion on the combustion chamber's exit temperature fields. The rig made use of the engine's diffuser tubes, combustion case, combustion liner, and first stage nozzle guide vane shield. Rig operating conditions simulated engine cruise conditions, matching the quasi-non-dimensional Mach number, equivalence ratio and Sauter mean diameter. The combustion chamber was tested with an even distribution of inlet air and a 4% difference in airflow at either side. An even distribution of inlet air to the combustion chamber did not create a uniform temperature profile and varying the inlet distribution of air exacerbated the profile's non-uniformity. The design of the combustion liner promoted the formation of an oval-shaped toroidal vortex inside the chamber, creating localized hot and cool sections separated by 90° that appeared in the exhaust. Uneven inlet air distributions skewed the oval vortex, increasing the temperature of the hot section nearest the side with the most mass flow rate and decreasing the temperature of the hot section on the opposite side. Keywords: Allison 250, Combustion, Dual-Entry, Exit Temperature Profile, Gas Turbine, Pattern Factor, Reverse Flow.

Maqsood, Omar Shahzada

412

Common Excess Air Trends in Industrial Boilers with Single-Point Positioning Control and Strategies to Optimize Efficiency  

E-print Network

Common Excess Air Trends in Industrial Boilers with Single-Point Positioning Control and Strategies mechanically linking the fuel valve and combustion air damper. To match combustion air flow with fuel input air control in boilers and methods to quantify both boiler efficiency as a function of excess air

Kissock, Kelly

413

A model for premixed combustion oscillations  

SciTech Connect

Combustion oscillations are receiving renewed research interest due to increasing application of lean premix (LPM) combustion to gas turbines. A simple, nonlinear model for premixed combustion is described; it was developed to explain experimental results and to provide guidance for developing active control schemes based on nonlinear concepts. The model can be used to quickly examine instability trends associated with changes in equivalence ratio, mass flow rate, geometry, ambient conditions, etc. The model represents the relevant processes occurring in a fuel nozzle and combustor analogous to current LPM turbine combustors. Conservation equations for the nozzle and combustor are developed from simple control volume analysis, providing ordinary differential equations that can be solved on a PC. Combustion is modeled as a stirred reactor, with bimolecular reaction between fuel and air. Although focus is on the model, it and experimental results are compared to understand effects of inlet air temperature and open loop control schemes. The model shows that both are related to changes in transport time.

Janus, M.C.; Richards, G.A.

1996-03-01

414

Mass air flow engine control system with mass air event integrator  

Microsoft Academic Search

This patent describes a mass air flow metering system of the type responsive to the mass of air flowing into an internal combustion engine. It comprises: a mass air flow sensor providing an output signal V{sub {ital out}} responsive to mass air flow; an analog to digital converter connected to receive the output signal V{sub {ital out}} which produces a

H. E. Weissler; B. G. Shirley

1991-01-01

415

Air Pollution: History Air Pollution: Any atmospheric constituent present as a result of  

E-print Network

Air Pollution: History Air Pollution: Any atmospheric constituent present as a result, or materials. Before 1200 AD · Air pollution results from wood burning, tanning, decaying trash, smelting = industrial revolution ­ x100 increase in G.B. coal combustion between 1800-1900 estimated air pollution in G

Weber, Rodney

416

Characteristics of the thermal regime of circular tube combustion chambers with combined wall cooling  

NASA Astrophysics Data System (ADS)

The thermal characteristics of circular tube gas turbine engine combustion chambers cooled by external blowing and the creation of an internal air-enclosed sheet are investigated. Combustion chamber wall temperatures were measured as a function of air flow parameters and fuel type (kerosene or natural gas) for two flame tube configurations. It is found that kerosene combustion leads to a higher wall temperature than natural gas, while increased air temperature increases wall temperature and air pressure is observed to have no effect in the range studied. It is also observed that the gas delivery scheme has little influence on wall temperature, while the influence of the air excess coefficient and the entrance velocity are shown to depend on flame tube air intake geometry. Results indicate that local combustion chamber wall temperatures may be lowered by creating additional flame tube openings or by drilling existing ones.

Didenko, V. I.; Khristich, V. A.; Liubchik, G. N.; Shevchenko, A. M.

1980-03-01

417

Design factors for stable lean premix combustion  

SciTech Connect

The Advanced Turbine Systems (ATS) program includes the development of low-emission combustors. Low emissions have already been achieved by premixing fuel and air to avoid the hot gas pockets produced by nozzles without premixing. While the advantages of premixed combustion have been widely recognized, turbine developers using premixed nozzles have experienced repeated problems with combustion oscillations. Left uncontrolled, these oscillations can lead to pressure fluctuations capable of damaging engine hardware. Elimination of such oscillations is often difficult and time consuming - particularly when oscillations are discovered in the last stages of engine development. To address this issue, METC is studying oscillating combustion from lean premixing fuel nozzles. These tests are providing generic information on the mechanisms that contribute to oscillating behavior in gas turbines. METC is also investigating the use of so-called {open_quotes}active{close_quotes} control of combustion oscillations. This technique periodically injects fuel pulses into the combustor to disrupt the oscillating behavior. Recent results on active combustion control are presented in Gemmen et al. (1995) and Richards et al. (1995). This paper describes the status of METC efforts to avoid oscillations through simple design changes.

Richards, G.; Yip, M.; Gemmen, R.

1995-12-31

418

Reproductive adaptation in Drosophila exposed to oxygen-enriched atmospheres  

NASA Technical Reports Server (NTRS)

Ten successive generations of a Drosophila melanogaster population were exposed to an atmospheric mix of 50% oxygen/50% nitrogen at standard pressure. This atmospheric mix has been shown to be toxic to this species and causes significantly shortened life span. By the fifth generation, survivorship and life span for the first 25-30 days were identical to control populations and total life span was shorter by only a few days. Egg-laying rates were stable in the experimental populations but below those of the controls. Hatching success was identical between experimental and control populations. Even though the egg-laying rates were lower in 50% oxygen, it was concluded that the population had adapted and could maintain a stable population in these conditions. The near-normal life spans, normal hatching rates, and overall population stability, exhibited following five generations of adaptation, were considered sufficient to allow continued reproduction in spite of a reduced egg-laying rate.

Kloek, G.; Winkle, L.

1979-01-01

419

Large-scale coherent structures as drivers of combustion instability  

SciTech Connect

The role of flow coherent structures as drivers of combustion instabilities in a dump combustor was studied. Results of nonreacting tests in air and water flows as well as combustion experiments in a diffusion flame and dump combustor are discussed to provide insight into the generation process of large-scale structures in the combustor flows and their interaction with the combustion process. It is shown that the flow structures, or vortices, are formed by interaction between the flow instabilities and the chamber acoustic resonance. When these vortices dominate the reacting flow, the combustion is confined initially to the circumference of their cores and further downstream proceeds into their core, leading to periodic heat release, which may result in the driving of high amplitude pressure oscillations. These oscillations are typical to the occurrence of combustion instabilities for certain operating conditions.

Schadow, K.C.; Gutmark, E.; Parr, T.P.; Wilson, K.J.; Crump, J.E. (Naval Weapons Center, China Lake, CA (USA). Research Dept.)

1989-01-01

420

Method and apparatus for reducing automotive pollution  

Microsoft Academic Search

Apparatus for reduction of pollutant emissions by internal combustion engines includes a tapered, coaxial multiconical structure used as a gas separator. The gas separator is used to provide oxygen enriched air to an engine, thus providing a reduction in the amount of nitrogen provided thereto. The resulting exhaust gas includes fewer oxides of nitrogen, reduced quantities of hydrocarbons, and decreased

Brettler

1982-01-01

421

Process and apparatus for the instantaneous combustion of diafanous liquid petroleum, diesel or similar fuels  

SciTech Connect

A process and apparatus for the production of heat, equivalent in clarity and cleanliness to that of propane, butane or natural gas, but at a lower cost and without the problems or dangers of storage nor risks of fire or explosion during handling, by means of the instantaneous combustion of diafanous liquid petroleum, diesel or other similar combustible fuels mixed with compressed air in an environment which is neither contaminated nor degraded. Thus, it is possible to regulate the flow and simultaneously divide each volume of combustible liquid into particles so small that they distribute and integrate themslves homogenously in a volume of air proportionally adequate for proper combustion.

Mendoza, F.C.

1980-10-07

422

Comparison of combustion efficiencies for ramjet engines  

NASA Technical Reports Server (NTRS)

Four different combustion efficiencies commonly used for assessing ramjet engines are compared. The mixture ratios cover a range from stoichiometric to an equivalence ratio of 0.2, and the polyethylene/air propellant system is used. The ratio of effective to ideal temperature rise is taken as reference efficiency. As might be expected, major differences can be observed near stoichiometric and down to equilvalence ratios of 0.5. These are quantitatively demonstrated.

Bergmann, J. W.

1984-01-01

423

Modelling and experiments of straw combustion in a grate furnace  

Microsoft Academic Search

A two-dimensional mathematical model for the combustion of straw in a cross-current, moving bed was developed as part of a tool for optimizing operating conditions and design parameters. To verify the model and to increase the understanding of straw bed combustion, laboratory fixed-bed experiments were performed in a 15cm diameter and 137cm long vertical reactor. Air was introduced through the

R. P van der Lans; L. T Pedersen; A Jensen; P Glarborg; K Dam-Johansen

2000-01-01

424

Combustion of liquid fuel in the counter-swirled jets of a gas turbine plant annular combustion chamber  

NASA Astrophysics Data System (ADS)

Tests were carried out on an annular combustion chamber rig with a stabilizer of the type used in the GTN-25 gas turbine plant to determine the feasibility of burning a liquid fuel (diesel fuel, GOST 4749-73) in a combustion chamber of this type. Very high performance was obtained for a number of important characteristics of the microflame combustion process in counterswirled jets where all the air was supplied through the front unit of the chamber. However, the tests did not make it possible to solve some of the problems which arise when operating under full-scale conditions, such as the required high combustion efficiency under variable operating conditions of a gas turbine plant; elimination of soot formation at the walls of the stabilizer and the internal surfaces of the pipes supplying fuel to the atomizers; and a decrease in smoking under conditions of excess air factor.

Tumanovskii, A. G.; Semichastnyi, N. N.; Sokolov, K. Iu.

1986-03-01

425

The combustion rate of volatiles in a fluidized bed combustor  

SciTech Connect

The combustion rate of coal volatiles within the dense phase is controlled by the rate of mixing with oxygen from the fluidizing air. Multiple discrete diffusion flame and plume models for volatiles combustion assume that this rate is determined by a radial dispersion coefficient, which characterizes the lateral mixing rate at the boundary between a plume of volatiles rising through the bed and the adjacent oxygen-containing region. The radial dispersion of tracer gas has been resolved into plume meandering and turbulent components, and the combustion rate of volatiles was assumed to be controlled by the turbulent dispersion coefficient. This paper investigates the applicability of the plume model with these turbulent dispersion coefficients to the prediction of the combustion rate of volatiles within the bed. Tracer gas and combustion experiments were performed at 850--900 C in the same fluidized bed. Nitrogen tracer gas and volatiles (simulated by propane) were injected through a single injector at the base of the air-fluidized bed. Time-resolved oxygen concentrations were measured in-situ by a Zirconia oxygen sensor for resolution into the radial dispersion components. The radial dispersion coefficient for volatiles combustion rate was deduced by fitting plume model predictions to measurements of the heat release rate within the bed. The turbulent radial dispersion was compared to the radial dispersion for combustion. Within experimental error, the turbulent radial dispersion coefficient could be used in the plume model to predict the in-bed combustion rate of volatiles only for the 1.55mm sand particles. For the 0.78 and 0.55mm sand particles, the turbulent dispersion coefficient was substantially lower than the combustion dispersion coefficient. This was attributed to the occurrence of clouded bubbles in the beds of smaller sand particles, to which the plume model cannot be applied. For small particle sizes, a different volatiles combustion model needs to be developed.

Stubington, J.F.; Clough, S.J. [Univ. of New South Wales, Sydney, New South Wales (Australia)

1997-12-31

426

Gas turbine combustion instability  

SciTech Connect

Combustion oscillations are a common problem in development of LPM (lean premix) combustors. Unlike earlier, diffusion style combustors, LPM combustors are especially susceptible to oscillations because acoustic losses are smaller and operation near lean blowoff produces a greater combustion response to disturbances in reactant supply, mixing, etc. In ongoing tests at METC, five instability mechanisms have been identified in subscale and commercial scale nozzle tests. Changes to fuel nozzle geometry showed that it is possible to stabilize combustion by altering the timing of the feedback between acoustic waves and the variation in heat release.

Richards, G.A.; Lee, G.T.

1996-09-01

427

Oxy-coal Combustion Studies  

SciTech Connect

The objective of this project is to move toward the development of a predictive capability with quantified uncertainty bounds for pilot-scale, single-burner, oxy-coal operation. This validation research brings together multi-scale experimental measurements and computer simulations. The combination of simulation development and validation experiments is designed to lead to predictive tools for the performance of existing air fired pulverized coal boilers that have been retrofitted to various oxy-firing configurations. In addition, this report also describes novel research results related to oxy-combustion in circulating fluidized beds. For pulverized coal combustion configurations, particular attention is focused on the effect of oxy-firing on ignition and coal-flame stability, and on the subsequent partitioning mechanisms of the ash aerosol. To these ends, the project has focused on the following: â?¢ The development of reliable Large Eddy Simulations (LES) of oxy-coal flames using the Direct Quadrature Method of Moments (DQMOM) (Subtask 3.1). The simulations were validated for both non-reacting particle-laden jets and oxy-coal flames. â?¢ The modifications of an existing oxy-coal combustor to allow operation with high levels of input oxygen to enable in-situ laser diagnostic measurements as well as the development of strategies for directed oxygen injection (Subtask 3.2). Flame stability was quantified for various burner configurations. One configuration that was explored was to inject all the oxygen as a pure gas within an annular oxygen lance, with burner aerodynamics controlling the subsequent mixing. â?¢ The development of Particle Image Velocimetry (PIV) for identification of velocity fields in turbulent oxy-coal flames in order to provide high-fidelity data for the validation of oxy-coal simulation models (Subtask 3.3). Initial efforts utilized a laboratory diffusion flame, first using gas-fuel and later a pulverized-coal flame to ensure the methodology was properly implemented and that all necessary data and image-processing techniques were fully developed. Success at this stage of development led to application of the diagnostics in a large-scale oxy-fuel combustor (OFC). â?¢ The impact of oxy-coal-fired vs. air-fired environments on SO{sub x} (SO{sub 2}, SO{sub 3}) emissions during coal combustion in a pilot-scale circulating fluidized-bed (CFB) (Subtask 3.4). Profiles of species concentration and temperature were obtained for both conditions, and profiles of temperature over a wide range of O{sub 2} concentration were studied for oxy-firing conditions. The effect of limestone addition on SO{sub 2} and SO{sub 3} emissions were also examined for both air- and oxy- firing conditions. â?¢ The investigation of O{sub 2}/CO{sub 2} and O{sub 2}/N{sub 2} environments on SO{sub 2 emissions during coal combustion in a bench-scale single-particle fluidized-bed reactor (Subtask 3.5). Moreover, the sulfation mechanisms of limestone in O{sub 2}/CO{sub 2} and O{sub 2}/N{sub 2} environments were studied, and a generalized gassolid and diffusion-reaction single-particle model was developed to study the effect of major operating variables. â?¢ The investigation of the effect of oxy-coal combustion on ash formation, particle size distributions (PSD), and size-segregated elemental composition in a drop-tube furnace and the 100 kW OFC (Subtask 3.6). In particular, the effect of coal type and flue gas recycle (FGR, OFC only) was investigated.

J. Wendt; E. Eddings; J. Lighty; T. Ring; P. Smith; J. Thornock; Y. Jia, W. Morris; J. Pedel; D. Rezeai; L. Wang; J. Zhang; K. Kelly

2012-01-01

428

Sandia Combustion Research: Technical review  

SciTech Connect

This report contains reports from research programs conducted at the Sandia Combustion Research Facility. Research is presented under the following topics: laser based diagnostics; combustion chemistry; reacting flow; combustion in engines and commercial burners; coal combustion; and industrial processing. Individual projects were processed separately for entry onto the DOE databases.

NONE

1995-07-01

429

Combustion Technology Outreach  

NASA Technical Reports Server (NTRS)

Lewis' High Speed Research (HSR) Propulsion Project Office initiated a targeted outreach effort to market combustion-related technologies developed at Lewis for the next generation of supersonic civil transport vehicles. These combustion-related innovations range from emissions measurement and reduction technologies, to diagnostics, spray technologies, NOx and SOx reduction of burners, noise reduction, sensors, and fuel-injection technologies. The Ohio Aerospace Institute and the Great Lakes Industrial Technology Center joined forces to assist Lewis' HSR Office in this outreach activity. From a database of thousands of nonaerospace firms considered likely to be interested in Lewis' combustion and emission-related technologies, the outreach team selected 41 companies to contact. The selected companies represent oil-gas refineries, vehicle/parts suppliers, and manufacturers of residential furnaces, power turbines, nonautomobile engines, and diesel internal combustion engines.

1995-01-01

430

COMBUSTION - RISK MANAGEMENT  

EPA Science Inventory

This research involves the characterization of waste combustion systems and their emissions along with the development and evaluation of techniques to prevent emissions formation and/or control their release. This area addresses incinerators and industrial systems burning wastes...

431

Pulsed atmospheric fluidized bed combustion  

SciTech Connect

The design of the Pulsed Atmospheric Fluidized Bed Combustor (PAFBC) as described in the Quarterly Report for the period April--June, 1992 was reviewed and minor modifications were included. The most important change made was in the coal/limestone preparation and feed system. Instead of procuring pre-sized coal for testing of the PAFBC, it was decided that the installation of a milling system would permit greater flexibility in the testing with respect to size distributions and combustion characteristics in the pulse combustor and the fluid bed. Particle size separation for pulse combustor and fluid bed will be performed by an air classifier. The modified process flow diagram for the coal/limestone handling system is presented in Figure 1. The modified process flow diagrams of the fluidized bed/steam cycle and ash handling systems are presented in Figures 2 and 3, respectively.

Not Available

1992-10-01

432

Solid fuel combustion system for gas turbine engine  

DOEpatents

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.

Wilkes, Colin (Lebanon, IN); Mongia, Hukam C. (Carmel, IN)

1993-01-01

433

Investigation of shock-induced combustion past blunt projectiles  

NASA Technical Reports Server (NTRS)

A numerical study is conducted to simulate shock-induced combustion in premixed hydrogen-air mixtures at various free-stream conditions and parameters. Two-dimensional axisymmetric, reacting viscous flow over blunt projectiles is computed to study shock-induced combustion at Mach 5.11 and Mach 6.46 in hydrogen-air mixture. A seven-species, seven reactions finite rate hydrogen-air chemical reaction mechanism is used combined with a finite-difference, shock-fitting method to solve the complete set of Navier-Stokes and species conservation equations. The study has allowed an improved understanding of the physics of shock-induced combustion over blunt projectiles and the numerical results can now be explained more readily with one-dimensional wave-interaction model.

Ahuja, J. K.; Tiwari, S. N.

1996-01-01

434

Turbine-driven air-powered flare  

Microsoft Academic Search

This patent describes an air powered flare in which the blower or fan which provides the primary combustion air, is driven by a steam turbine, and the exhaust steam from the turbine is inserted into the stack to be mixed with the compressed primary air moving upwardly to a burner at the top of the flare stack. The mixture of

R. D. Reed; R. E. Schwartz; R. K. Noble

1977-01-01

435

Introduction Air Quality and Nitrogen Dioxide  

E-print Network

Introduction Air Quality and Nitrogen Dioxide Air pollution can be defined as "the presence worldwide" WHO Air quality guidelines for particulate matter, ozone, nitrogen dioxide and sulphur dioxide and motor vehicles. Nitrogen Dioxide is produced in a number of combustion processes. Nitrogen dioxide can

436

75 FR 35519 - Primary National Ambient Air Quality Standard for Sulfur Dioxide  

Federal Register 2010, 2011, 2012, 2013

...power plants and other fossil fuel combustion facilities...metropolitan air quality statistics, and therefore...the key air quality statistic from that period to...the key air quality statistics are...

2010-06-22

437

Combustion Assisted Gravity Drainage (CAGD): An In-Situ Combustion Method to Recover Heavy Oil and Bitumen from Geologic Formations using a Horizontal Injector/Producer Pair  

E-print Network

, air was injected through dual parallel wells in a mature steam chamber. Laboratory results showed that the process can effectively create self-sustained combustion front in the previously steam-operated porous media. A maximum temperature of 617º...

Rahnema, Hamid

2012-11-21

438

Particulate emissions from residential wood combustion: Final report: Norteast regional Biomass Program  

SciTech Connect

The objective of this study was to provide a resource document for the Northeastern states when pursuing the analysis of localized problems resulting from residential wood combustion. Specific tasks performed include assigning emission rates for total suspended particulates (TSP) and benzo(a)pyrene (BaP) from wood burning stoves, estimating the impact on ambient air quality from residential wood combustion and elucidating the policy options available to Northeastern states in their effort to limit any detrimental effects resulting from residential wood combustion. Ancillary tasks included providing a comprehensive review on the relevant health effects, indoor air pollution and toxic air pollutant studies. 77 refs., 11 figs., 25 tabs.

Not Available

1987-01-01

439

Gas turbine control system having optimized ignition air flow control  

Microsoft Academic Search

This patent describes apparatus for generating an ignition enabling signal for use with a given combustion turbine, wherein a turbine speed signal is given and wherein the combustion turbine includes ignition means for igniting the turbine in response to an ignition enabling signal. It comprises: sensor means for sensing the temperature of ambient air and for generating an ambient air

S. E. Mumford; W. L. McCarty

1992-01-01

440

Air Resources Laboratory Research and Development  

E-print Network

in the respiratory system. PM2.5 is emitted directly into the air from combustion processes (burning of fossil fuels hair), are especially dangerous to human health because they can be inhaled into and accumulate

441

Effects of Air Pollution Control on Climate  

E-print Network

Urban air pollution and climate are closely connected due to shared generating processes (e.g., combustion) for emissions of the driving gases and aerosols. They are also connected because the atmospheric lifecycles of ...

Prinn, Ronald G.

442

Ignition and combustion: Low compression ratio, high output diesel  

NASA Technical Reports Server (NTRS)

The feasibility of converting a spark ignition aircraft engine GTSI0-520 to compression ignition without increasing the peak combustion pressure of 1100 lbs/sq.in. was determined. The final contemplated utilized intake air heating at idle and light load and a compression ratio of about 10:1 with a small amount of fumigation (the addition of about 15% fuel into the combustion air before the cylinder). The engine used was a modification of a Continental-Teledyne gasoline engine cylinder from the GTSI0-520 supercharged aircraft engine.

1981-01-01

443

Effects of high temperature and combustion on fluidized material attrition in a fluidized bed  

Microsoft Academic Search

This study investigated the effects of high temperature and combustion conditions on the attrition of fluidized material in\\u000a a fluidized bed. Silica sand was fluidized in air at an atmospheric pressure between 873 K and 1,073 K. The operating parameters\\u000a evaluated in investigating the attrition rate of fluidized material included particle size, temperature and both combustion\\u000a and non-combustion conditions. Experimental

Chiou-Liang Lin; Ming-Yen Wey

2003-01-01

444

Co-combustion of pellets from Soma lignite and waste dusts of furniture works  

SciTech Connect

In this work, volatiles and char combustion behaviors of the fuel pellets prepared from a low quality lignite and the dusts of furniture works and their various blends were investigated in an experimental fixed bed combustion system through which air flowed by natural convection. Combustion data obtained for varied bed temperatures, mass of pellets, and blend compositions has showed that ignition times of the pellets decreased and volatiles combustion rates tended to increase with the burning temperature. It was concluded that some synergy had existed between lignite and lower ratios of furniture work dusts, which was indicated by a prompt effect on the volatiles combustion rates. Char combustion rates of blend pellets have depended predominantly on the amount of lignite in the blend. The amounts of combustion residues of the pellets were considerably higher than those calculated from individual ash contents of the raw materials and related to lignite ratio in the blends.

Deveci, N.D.; Yilgin, M.; Pehlivan, D. [Firat University, Elazig (Turkey). Faculty of Engineering

2008-07-01

445

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

NASA Technical Reports Server (NTRS)

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.

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

1996-01-01

446

Advanced Subsonic Combustion Rig  

NASA Technical Reports Server (NTRS)

Researchers from the NASA Lewis Research Center have obtained the first combustion/emissions data under extreme future engine operating conditions. In Lewis' new world-class 60-atm combustor research facility--the Advanced Subsonic Combustion Rig (ASCR)--a flametube was used to conduct combustion experiments in environments as extreme as 900 psia and 3400 F. The greatest challenge for combustion researchers is the uncertainty of the effects of pressure on the formation of nitrogen oxides (NOx). Consequently, U.S. engine manufacturers are using these data to guide their future combustor designs. The flametube's metal housing has an inside diameter of 12 in. and a length of 10.5 in. The flametube can be used with a variety of different flow paths. Each flow path is lined with a high-temperature, castable refractory material (alumina) to minimize heat loss. Upstream of the flametube is the injector section, which has an inside diameter of 13 in. and a length of 0.5-in. It was designed to provide for quick changeovers. This flametube is being used to provide all U.S. engine manufacturers early assessments of advanced combustion concepts at full power conditions prior to engine production. To date, seven concepts from engine manufacturers have been evaluated and improved. This collaborated development can potentially give U.S. engine manufacturers the competitive advantage of being first in the market with advanced low-emission technologies.

Lee, Chi-Ming

1998-01-01

447

Environmentally conscious coal combustion  

SciTech Connect

This is the final report of a one-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The objective of this project was to evaluate the environmental impacts of home-scale coal combustion on the Navajo Reservation and develop strategies to reduce adverse health effects associated with home-scale coal combustion. Principal accomplishments of this project were: (1) determination of the metal and gaseous emissions of a representative stove on the Navajo Reservation; (2) recognition of cyclic gaseous emissions in combustion in home-scale combustors; (3) `back of the envelope` calculation that home-scale coal combustion may impact Navajo health; and (4) identification that improved coal stoves require the ability to burn diverse feedstocks (coal, wood, biomass). Ultimately the results of Navajo home-scale coal combustion studies will be extended to the Developing World, particularly China, where a significant number (> 150 million) of households continue to heat their homes with low-grade coal.

Hickmott, D.D.; Brown, L.F.; Currier, R.P. [and others

1997-08-01

448

Co-combustion performance of poultry wastes and natural gas in the advanced Swirling Fluidized Bed Combustor (SFBC).  

PubMed

Co-combustion of poultry wastes with natural gas in an advanced Swirling Fluidized Bed Combustor (SFBC) has been carried out to investigate the performance of poultry wastes combustion. Wastes burnt were poultry litter, poultry manure and sawdust. This paper presents the effect of three different wastes, excess air ratio, and secondary/total air ratio on the combustion characteristics. These characteristics include temperature distributions, carbon combustion efficiency, major gaseous pollutants emissions and heat recovery efficiency. The results indicate that, with the given moisture and ash contents in wastes, the excess air and the secondary air play important roles in achieving stable combustion. The carbon combustion efficiency could increase by 8-10% when the excess air is increased to 25% with the secondary air being at 20% and having a low injection height. However, the carbon combustion efficiency for the sawdust, which is 92% on average, is much higher than that of the poultry litter and manure, which is 81% and 76% on average, respectively. Differences regarding temperature distribution and pollutants emission were also observed with different combinations of the excess air, the secondary air and the secondary air injection height. The NO(x) emission was very low even though the materials contain high levels of nitrogen. In addition, the heat recovery efficiency aiming at the commercial use of the SFBC system for the farm industries was also evaluated. PMID:15925760

Zhu, S; Lee, S W

2005-01-01

449

Co-combustion of textile residues with cardboard and waste wood in a packed bed  

SciTech Connect

The combustible fraction of the municipal waste is mostly bio-derived. Energy recovery of the wastes that cannot be economically recycled is a key part of sustainable energy policy and waste management. Textile residues have high energy content. When burned alone in a packed bed system, however, their combustion efficiency is low due to the irregular propagation of the ignition front and the low burning rates. In order to achieve more efficient combustion of textile residues, a series of co-combustion tests were carried out for various mixture compositions and air flow rates in a packed bed combustor. The combustion performance of these materials was evaluated by using quantitative measures such as ignition rate, burning rate and equivalence ratio. Co-combustion of textile residues with cardboard for a textile fraction of up to 30% achieved satisfactorily high burning rate and low unburned carbon content in the bottom ash. The mixture was more resistant to convective cooling by air, which significantly expanded the range of air flow rate for combustion at high burning rates. In co-combustion with a material that has a very low ignition front speed such as waste wood, the propagation of the ignition front was governed by textile residues. Therefore, the co-combustion of textile residues can be better performed with a material having similar ignition front speeds, in which the two materials simultaneously burn at the ignition front. (author)

Ryu, Changkook; Phan, Anh N; Sharifi, Vida N; Swithenbank, Jim [Sheffield University Waste Incineration Centre (SUWIC), Department of Chemical and Process Engineering, The University of Sheffield, Mappin Street, Sheffield S1 3JD (United Kingdom)

2007-11-15

450

External combustion engine having a combustion expansion chamber  

NASA Astrophysics Data System (ADS)

This patent application discloses an external combustion engine having a combustion expansion chamber. The engine includes a combustion chamber for generating a high-pressure, energized gas from a monopropellant fuel, and a cylinder for receiving the energized gas through a rotary valve to perform work on a cylinder disposed therein. A baffle plate is positioned between the combustion area and expansion area for reducing the pressure of the gas. The combustion area and expansion area are separated by a baffle plate having a flow area which is sufficiently large to eliminate the transmission of pressure pulsations from the combustion area to the expansion area while being small enough to provide for substantially complete combustion in the combustion area. The engine is particularly well suited for use in a torpedo.

Duva, Anthony W.

1993-03-01

451

Combustible structural composites and methods of forming combustible structural composites  

DOEpatents

Combustible structural composites and methods of forming same are disclosed. In an embodiment, a combustible structural composite includes combustible material comprising a fuel metal and a metal oxide. The fuel metal is present in the combustible material at a weight ratio from 1:9 to 1:1 of the fuel metal to the metal oxide. The fuel metal and the metal oxide are capable of exothermically reacting upon application of energy at or above a threshold value to support self-sustaining combustion of the combustible material within the combustible structural composite. Structural-reinforcing fibers are present in the composite at a weight ratio from 1:20 to 10:1 of the structural-reinforcing fibers to the combustible material. Other embodiments and aspects are disclosed.

Daniels, Michael A.; Heaps, Ronald J.; Steffler, Eric D.; Swank, W. David

2013-04-02

452

Combustible structural composites and methods of forming combustible structural composites  

DOEpatents

Combustible structural composites and methods of forming same are disclosed. In an embodiment, a combustible structural composite includes combustible material comprising a fuel metal and a metal oxide. The fuel metal is present in the combustible material at a weight ratio from 1:9 to 1:1 of the fuel metal to the metal oxide. The fuel metal and the metal oxide are capable of exothermically reacting upon application of energy at or above a threshold value to support self-sustaining combustion of the combustible material within the combustible structural composite. Structural-reinforcing fibers are present in the composite at a weight ratio from 1:20 to 10:1 of the structural-reinforcing fibers to the combustible material. Other embodiments and aspects are disclosed.

Daniels, Michael A. (Idaho Falls, ID); Heaps, Ronald J. (Idaho Falls, ID); Steffler, Eric D (Idaho Falls, ID); Swank, William D. (Idaho Falls, ID)

2011-08-30

453

Design and Operation of the Synthesis Gas Generator System for Reformed Propane and Glycerin Combustion  

E-print Network

components indicated………………………………………………. 8 Figure 5 - Air dryer (left) and custom flow separator (right) in line before air controller…………………………. 9 Figure 6 – Image of transformer powering igniter ………………………………………………………………………………… 10 Figure 7 - General Motors... rig……………………………………………………………… 20 Figure 16 - Air control system with important features indicated…………………………………………………………. 2